研究者業績

大栗 真宗

オオグリ マサムネ  (Masamune Oguri)

基本情報

所属
千葉大学 先進科学センター 教授
学位
博士(理学)(2004年7月 東京大学)

研究者番号
60598572
ORCID ID
 https://orcid.org/0000-0003-3484-399X
J-GLOBAL ID
201801017753358631
researchmap会員ID
B000310867

外部リンク

学歴

 3

論文

 345
  • Yuichi Harikane, Masami Ouchi, Masamune Oguri, Yoshiaki Ono, Kimihiko Nakajima, Yuki Isobe, Hiroya Umeda, Ken Mawatari, Yechi Zhang
    Astrophysical Journal, Supplement Series 265(1) 2023年3月1日  
    We conduct a comprehensive study on dropout galaxy candidates at z ∼ 9-16 using the first 90 arcmin2 James Webb Space Telescope (JWST) Near Infrared Camera images taken by the early release observations (ERO) and early release science programs. With the JWST simulation images, we find that a number of foreground interlopers are selected with a weak photo-z determination (Δχ 2 > 4). We thus carefully apply a secure photo-z selection criterion (Δχ 2 > 9) and conventional color criteria with confirmations of the ERO Near Infrared Spectrograph spectroscopic redshifts, and obtain a total of 23 dropout galaxies at z ∼ 9-16, including two candidates at z phot = 16.25 − 0.46 + 0.24 and 16.41 − 0.55 + 0.66 . We perform thorough comparisons of dropout galaxies found in our work with recent JWST studies, and conclude that our galaxy sample is reliable enough for statistical analyses. We derive the UV luminosity functions at z ∼ 9-16, and confirm that our UV luminosity functions at z ∼ 9 and 12 agree with those determined by other Hubble Space Telescope and JWST studies. The cosmic star formation rate (SFR) density decreases from z ∼ 9 to 12, and perhaps to 16, but the densities at z ∼ 12-16 are higher than the constant star formation efficiency model. Interestingly, there are six bright galaxy candidates at z ∼ 10-16 with M UV < −19.5 mag and M * ∼ 108−9 M ⊙. Because a majority (∼80%) of these galaxies show no signatures of active galactic nuclei in their morphologies, the high cosmic SFR densities and the existence of these UV-luminous galaxies are explained by the lack of suppression of star formation by the UV background radiation at the pre-reionization epoch and/or an efficient UV radiation production by a top-heavy initial mass function with Population III-like star formation.
  • Eros Vanzella, Adélaïde Claeyssens, Brian Welch, Angela Adamo, Dan Coe, Jose M. Diego, Guillaume Mahler, Gourav Khullar, Vasily Kokorev, Masamune Oguri, Swara Ravindranath, Lukas J. Furtak, Tiger Yu Yang Hsiao, Abdurro’uf, Nir Mandelker, Gabriel Brammer, Larry D. Bradley, Maruša Bradač, Christopher J. Conselice, Pratika Dayal, Mario Nonino, Felipe Andrade-Santos, Rogier A. Windhorst, Nor Pirzkal, Keren Sharon, S. E. de Mink, Seiji Fujimoto, Adi Zitrin, Jan J. Eldridge, Colin Norman
    Astrophysical Journal 945(1) 2023年3月1日  
    Star cluster formation in the early universe and its contribution to reionization remains largely unconstrained to date. Here we present JWST/NIRCam imaging of the most highly magnified galaxy known at z ∼ 6, the Sunrise arc. We identify six young massive star clusters (YMCs) with measured radii spanning from ∼20 down to ∼1 pc (corrected for lensing magnification), estimated stellar masses of ∼106-7 M ⊙, and ages of 1-30 Myr based on SED fitting to photometry measured in eight filters extending to rest frame 7000 Å. The resulting stellar mass surface densities are higher than 1000 M ⊙ pc−2 (up to a few 105 M ⊙ pc−2), and their inferred dynamical ages qualify the majority of these systems as gravitationally bound stellar clusters. The star cluster ages map the progression of star formation along the arc, with two evolved systems (≳10 Myr old) followed by very young clusters. The youngest stellar clusters (<5 Myr) show evidence of prominent Hβ+[O iii] emission based on photometry with equivalent widths larger than >1000 Å rest frame and are hosted in a 200 pc sized star-forming complex. Such a region dominates the ionizing photon production with a high efficiency log ( ξ ion [ Hz erg − 1 ] ) ∼ 25.7 . A significant fraction of the recently formed stellar mass of the galaxy (10%-30%) occurred in these YMCs. We speculate that such sources of ionizing radiation boost the ionizing photon production efficiency, which eventually carves ionized channels that might favor the escape of Lyman continuum radiation. The survival of some of the clusters would make them the progenitors of massive and relatively metal-poor globular clusters in the local universe.
  • Abdurro’uf, Dan Coe, Intae Jung, Henry C. Ferguson, Gabriel Brammer, Kartheik G. Iyer, Larry D. Bradley, Pratika Dayal, Rogier A. Windhorst, Adi Zitrin, Ashish Kumar Meena, Masamune Oguri, Jose M. Diego, Vasily Kokorev, Paola Dimauro, Angela Adamo, Christopher J. Conselice, Brian Welch, Eros Vanzella, Tiger Yu Yang Hsiao, Xinfeng Xu, Namrata Roy, Celia R. Mulcahey
    Astrophysical Journal 945(2) 2023年3月1日  
    We study the spatially resolved stellar populations of 444 galaxies at 0.3 < z < 6.0 in two clusters (WHL 0137-08 and MACS 0647+70) and a blank field, combining imaging data from the Hubble Space Telescope and JWST to perform spatially resolved spectral energy distribution (SED) modeling using piXedfit. The high spatial resolution of the imaging data combined with magnification from gravitational lensing in the cluster fields allows us to resolve a large fraction of our galaxies (109) to subkiloparsec scales. At redshifts around cosmic noon and higher (2.5 ≲ z ≲ 6.0), we find mass-doubling times to be independent of radius, inferred from flat specific star formation rate (sSFR) radial profiles and similarities between the half-mass and half-SFR radii. At lower redshifts (1.5 ≲ z ≲ 2.5), a significant fraction of our star-forming galaxies shows evidence for nuclear starbursts, inferred from a centrally elevated sSFR and a much smaller half-SFR radius compared to the half-mass radius. At later epochs, we find more galaxies suppress star formation in their centers but are still actively forming stars in the disk. Overall, these trends point toward a picture of inside-out galaxy growth consistent with theoretical models and simulations. We also observe a tight relationship between the central mass surface density and global stellar mass with ∼0.38 dex scatter. Our analysis demonstrates the potential of spatially resolved SED analysis with JWST data. Future analysis with larger samples will be able to further explore the assembly of galaxy mass and the growth of their structures.
  • Ashish Kumar Meena, Adi Zitrin, Yolanda Jiménez-Teja, Erik Zackrisson, Wenlei Chen, Dan Coe, Jose M. Diego, Paola Dimauro, Lukas J. Furtak, Patrick L. Kelly, Masamune Oguri, Brian Welch, Abdurro’uf None, Felipe Andrade-Santos, Angela Adamo, Rachana Bhatawdekar, Maruša Bradač, Larry D. Bradley, Tom Broadhurst, Christopher J. Conselice, Pratika Dayal, Megan Donahue, Brenda L. Frye, Seiji Fujimoto, Tiger Yu Yang Hsiao, Vasily Kokorev, Guillaume Mahler, Eros Vanzella, Rogier A. Windhorst
    Astrophysical Journal Letters 944(1) 2023年2月1日  
    We report the discovery of two extremely magnified lensed star candidates behind the galaxy cluster MACS J0647.7+015 using recent multiband James Webb Space Telescope (JWST) NIRCam observations. The star candidates are seen in a previously known, z phot ≃ 4.8 dropout giant arc that straddles the critical curve. The candidates lie near the expected critical curve position, but lack clear counter-images on the other side of it, suggesting these are possibly stars undergoing caustic crossings. We present revised lensing models for the cluster, including multiply imaged galaxies newly identified in the JWST data, and use them to estimate background macro-magnifications of at least ≳90 and ≳50 at the positions of the two candidates, respectively. With these values, we expect effective, caustic-crossing magnifications of ∼[103-105] for the two star candidates. The spectral energy distributions of the two candidates match well the spectra of B-type stars with best-fit surface temperatures of ∼10,000 K, and ∼12,000 K, respectively, and we show that such stars with masses ≳20 M ⊙ and ≳50 M ⊙, respectively, can become sufficiently magnified to be observable. We briefly discuss other alternative explanations and conclude that these objects are likely lensed stars, but also acknowledge that the less-magnified candidate may alternatively reside in a star cluster. These star candidates constitute the second highest-redshift examples to date after Earendel at z phot ≃ 6.2, establishing further the potential of studying extremely magnified stars at high redshifts with JWST. Planned future observations, including with NIRSpec, will enable a more detailed view of these candidates in the near future.
  • Yue Shen, Hsiang Chih Hwang, Masamune Oguri, Nianyi Chen, Tiziana Di Matteo, Yueying Ni, Simeon Bird, Nadia Zakamska, Xin Liu, Yu Ching Chen, Kaitlin M. Kratter
    Astrophysical Journal 943(1) 2023年1月1日  
    The statistics of galactic-scale quasar pairs can elucidate our understanding of the dynamical evolution of supermassive black hole (SMBH) pairs, the duty cycles of quasar activity in mergers, or even the nature of dark matter, but they have been challenging to measure at cosmic noon, the prime epoch of massive galaxy and SMBH formation. Here we measure a double quasar fraction of ∼6.2 ± 0.5 × 10−4 integrated over ∼0.″3-3″ separations (projected physical separations of ∼3-30 kpc at z ∼ 2) in luminous (L bol > 1045.8 erg s−1) unobscured quasars at 1.5 < z < 3.5 using Gaia EDR3-resolved pairs around SDSS DR16 quasars. The measurement was based on a sample of 60 Gaia-resolved double quasars (out of 487 Gaia pairs dominated by quasar+star superpositions) at these separations, corrected for pair completeness in Gaia, which we quantify as functions of pair separation, magnitude of the primary, and magnitude contrast. The double quasar fraction increases toward smaller separations by a factor of ∼5 over these scales. The division between physical quasar pairs and lensed quasars in our sample is currently unknown, requiring dedicated follow-up observations (in particular, deep, subarcsecond-resolution IR imaging for the closest pairs). Intriguingly, at this point, the observed pair statistics are in rough agreement with theoretical predictions both for the lensed quasar population in mock catalogs and for dual quasars in cosmological hydrodynamic simulations. Upcoming wide-field imaging/spectroscopic space missions such as Euclid, CSST, and Roman, combined with targeted follow-up observations, will conclusively measure the abundances and host galaxy properties of galactic-scale quasar pairs, offset AGNs, and subarcsecond lensed quasars across cosmic time.
  • N. Ota, N. T. Nguyen-Dang, I. Mitsuishi, M. Oguri, M. Klein, N. Okabe, M. E. Ramos-Ceja, T. H. Reiprich, F. Pacaud, E. Bulbul, M. Brüggen, A. Liu, K. Migkas, I. Chiu, V. Ghirardini, S. Grandis, Y. T. Lin, H. Miyatake, S. Miyazaki, J. S. Sanders
    Astronomy and Astrophysics 669 A110-A110 2023年1月1日  
    Context. We present the results of a systematic X-ray analysis of optically rich galaxy clusters detected by the Subaru Hyper Suprime-Cam (HSC) survey in the eROSITA Final Equatorial-Depth Survey (eFEDS) field. Aims. Through a joint analysis of the SRG (Spectrum Roentgen Gamma)/eROSITA and Subaru/HSC surveys, we aim to investigate the dynamical status of the optically selected clusters and to derive the cluster scaling relations. Methods. The sample consists of 43 optically selected galaxy clusters with a richness &gt;40 in the redshift range of 0.16–0.89. We systematically analyzed the X-ray images and emission spectra using the eROSITA data. We identified the brightest cluster galaxy (BCG) using the optical and far-infrared databases. We evaluated the cluster’s dynamical status by measuring three quantities: offset between the X-ray peak and BCG position, the gas concentration parameter, and the number of galaxy-density peaks. We investigated the luminosity–temperature and mass–luminosity relations based on eROSITA X-ray spectra and HSC weak-lensing data analyses. Results. Based on these three measurements, we estimated the fraction of relaxed clusters to be 2(&lt; 39)%, which is smaller than that of the X-ray-selected cluster samples. After correcting for a selection bias due to the richness cut, we obtained a shallow L−T slope of 2.1 ± 0.5, which is consistent with the predictions of the self-similar model and the baseline model incorporating a mass–concentration relation. The L−M slope of 1.5 ± 0.3 is in agreement with the above-cited theoretical models as well as the data on the shear-selected clusters in the eFEDs field. Conclusions. Our analysis of high-richness optical clusters yields a small fraction of relaxed clusters and a shallow slope for the luminosity–temperature relation. This suggests that the average X-ray properties of the optical clusters are likely to be different from those observed in the X-ray samples. Thus, the joint eROSITA and HSC observations are a powerful tool in extending the analysis to a larger sample and understanding the selection effect with a view to establish cluster scaling relations.
  • V. Kokorev, G. Brammer, S. Fujimoto, K. Kohno, G. E. Magdis, F. Valentino, S. Toft, P. Oesch, I. Davidzon, F. E. Bauer, D. Coe, E. Egami, M. Oguri, M. Ouchi, M. Postman, J. Richard, J. B. Jolly, K. K. Knudsen, F. Sun, J. R. Weaver, Y. Ao, A. J. Baker, L. Bradley, K. I. Caputi, M. Dessauges-Zavadsky, D. Espada, B. Hatsukade, A. M. Koekemoer, A. M. Muñoz Arancibia, K. Shimasaku, H. Umehata, T. Wang, W. H. Wang
    Astrophysical Journal, Supplement Series 263(2) 2022年12月1日  
    We present a set of multiwavelength mosaics and photometric catalogs in the Atacama Large Millimeter/ submillimeter Array (ALMA) lensing cluster survey fields. The catalogs were built by the reprocessing of archival data from the Complete Hubble Archive for Galaxy Evolution compilation, taken by the Hubble Space Telescope (HST) in the Reionization Lensing Cluster Survey, Cluster Lensing And Supernova survey with Hubble, and Hubble Frontier Fields. Additionally, we have reconstructed the Spitzer Infrared Array Camera 3.6 and 4.5 μm mosaics, by utilizing all the available archival IPAC Infrared Science Archive/Spitzer Heritage Archive exposures. To alleviate the effect of blending in such a crowded region, we have modeled the Spitzer photometry by convolving the HST detection image with the Spitzer point-spread function using the novel GOLFIR software. The final catalogs contain 218,000 sources, covering a combined area of 690 arcmin2, a factor of ∼2 improvement over the currently existing photometry. A large number of detected sources is a result of reprocessing of all available and sometimes deeper exposures, in conjunction with a combined optical–near-IR detection strategy. These data will serve as an important tool in aiding the search of the submillimeter galaxies in future ALMA surveys, as well as follow-ups of the HST dark and high-z sources with JWST. Coupled with the available HST photometry, the addition of the 3.6 and 4.5 μm bands will allow us to place a better constraint on the photometric redshifts and stellar masses of these objects, thus giving us an opportunity to identify high-redshift candidates for spectroscopic follow-ups and to answer the important questions regarding the Epoch of Reionization and formation of the first galaxies. The mosaics, photometric catalogs, and the best-fit physical properties are publicly available at https:// github.com/dawn-cph/alcs-clusters.
  • Brian Welch, Dan Coe, Erik Zackrisson, S. E. de Mink, Swara Ravindranath, Jay Anderson, Gabriel Brammer, Larry Bradley, Jinmi Yoon, Patrick Kelly, Jose M. Diego, Rogier Windhorst, Adi Zitrin, Paola Dimauro, Yolanda Jiménez-Teja, Abdurro’uf, Mario Nonino, Ana Acebron, Felipe Andrade-Santos, Roberto J. Avila, Matthew B. Bayliss, Alex Benítez, Tom Broadhurst, Rachana Bhatawdekar, Maruša Bradač, Gabriel B. Caminha, Wenlei Chen, Jan Eldridge, Ebraheem Farag, Michael Florian, Brenda Frye, Seiji Fujimoto, Sebastian Gomez, Alaina Henry, Tiger Y.Y. Hsiao, Taylor A. Hutchison, Bethan L. James, Meridith Joyce, Intae Jung, Gourav Khullar, Rebecca L. Larson, Guillaume Mahler, Nir Mandelker, Stephan McCandliss, Takahiro Morishita, Rosa Newshore, Colin Norman, Kyle O’Connor, Pascal A. Oesch, Masamune Oguri, Masami Ouchi, Marc Postman, Jane R. Rigby, Russell E. Ryan, Soniya Sharma, Keren Sharon, Victoria Strait, Louis Gregory Strolger, F. X. Timmes, Sune Toft, Michele Trenti, Eros Vanzella, Anton Vikaeus
    Astrophysical Journal Letters 940(1) 2022年11月1日  
    The gravitationally lensed star WHL 0137-LS, nicknamed Earendel, was identified with a photometric redshift z phot = 6.2 ± 0.1 based on images taken with the Hubble Space Telescope. Here we present James Webb Space Telescope (JWST) Near Infrared Camera images of Earendel in eight filters spanning 0.8-5.0 μm. In these higher-resolution images, Earendel remains a single unresolved point source on the lensing critical curve, increasing the lower limit on the lensing magnification to μ > 4000 and restricting the source plane radius further to r < 0.02 pc, or ∼4000 au. These new observations strengthen the conclusion that Earendel is best explained by an individual star or multiple star system and support the previous photometric redshift estimate. Fitting grids of stellar spectra to our photometry yields a stellar temperature of T eff ≃ 13,000-16,000 K, assuming the light is dominated by a single star. The delensed bolometric luminosity in this case ranges from log ( L ) = 5.8 to 6.6 L ⊙, which is in the range where one expects luminous blue variable stars. Follow-up observations, including JWST NIRSpec scheduled for late 2022, are needed to further unravel the nature of this object, which presents a unique opportunity to study massive stars in the first billion years of the universe.
  • Wenlei Chen, Patrick L. Kelly, Masamune Oguri, Thomas J. Broadhurst, Jose M. Diego, Najmeh Emami, Alexei V. Filippenko, Tommaso L. Treu, Adi Zitrin
    Nature 611(7935) 256-259 2022年11月1日  
    The core-collapse supernova of a massive star rapidly brightens when a shock, produced following the collapse of its core, reaches the stellar surface. As the shock-heated star subsequently expands and cools, its early-time light curve should have a simple dependence on the size of the progenitor1 and therefore final evolutionary state. Measurements of the radius of the progenitor from early light curves exist for only a small sample of nearby supernovae2-14, and almost all lack constraining ultraviolet observations within a day of explosion. The several-day time delays and magnifying ability of galaxy-scale gravitational lenses, however, should provide a powerful tool for measuring the early light curves of distant supernovae, and thereby studying massive stellar populations at high redshift. Here we analyse individual rest-frame exposures in the ultraviolet to the optical taken with the Hubble Space Telescope, which simultaneously capture, in three separate gravitationally lensed images, the early phases of a supernova at redshift z ≈ 3 beginning within 5.8 ± 3.1 hours of explosion. The supernova, seen at a lookback time of approximately 11.5 billion years, is strongly lensed by an early-type galaxy in the Abell 370 cluster. We constrain the pre-explosion radius to be [Formula: see text] solar radii, consistent with a red supergiant. Highly confined and massive circumstellar material at the same radius can also reproduce the light curve, but because no similar low-redshift examples are known, this is unlikely.
  • Hironao Miyatake, Sunao Sugiyama, Masahiro Takada, Takahiro Nishimichi, Masato Shirasaki, Yosuke Kobayashi, Rachel Mandelbaum, Surhud More, Masamune Oguri, Ken Osato, Youngsoo Park, Ryuichi Takahashi, Jean Coupon, Chiaki Hikage, Bau Ching Hsieh, Yutaka Komiyama, Alexie Leauthaud, Xiangchong Li, Wentao Luo, Robert H. Lupton, Satoshi Miyazaki, Hitoshi Murayama, Atsushi J. Nishizawa, Paul A. Price, Melanie Simet, Joshua S. Speagle, Michael A. Strauss, Masayuki Tanaka, Naoki Yoshida
    Physical Review D 106(8) 2022年10月15日  
    We present high-fidelity cosmology results from a blinded joint analysis of galaxy-galaxy weak lensing (Δς) and projected galaxy clustering (wp) measured from the Hyper Suprime-Cam Year-1 (HSC-Y1) data and spectroscopic Sloan Digital Sky Survey (SDSS) galaxy catalogs in the redshift range 0.15<z<0.7. We define luminosity-limited samples of SDSS galaxies to serve as the tracers of wp in three spectroscopic redshift bins, and as the lens samples for Δς. For the Δς measurements, we select a single sample of 4×106 source galaxies over 140 deg2 from HSC-Y1 with photometric redshifts (photo z) greater than 0.75, enabling a better handle of photo-z errors by comparing the Δς amplitudes for the three lens redshift bins. The deep, high-quality HSC-Y1 data enable significant detections of the Δς signals, with integrated signal-to-noise ratio S/N∼15 in the range 3≤R/[h-1 Mpc]≤30 for the three lens samples, despite the small area coverage. For cosmological parameter inference, we use an input galaxy-halo connection model built on the dark emulator package (which uses an ensemble set of high-resolution N-body simulations and enables fast, accurate computation of the clustering observables) with a halo occupation distribution that includes nuisance parameters to marginalize over modeling uncertainties. We model the Δς and wp measurements on scales from R≃3 and 2 h-1 Mpc, respectively, up to 30 h-1 Mpc (therefore excluding the baryon acoustic oscillations information) assuming a flat ΛCDM cosmology, marginalizing over about 20 nuisance parameters and demonstrating the robustness of our results to them. With various tests using mock catalogs described in Miyatake et al. [preceding paper, Phys. Rev. D 106, 083519 (2022)10.1103/PhysRevD.106.083519], we show that any bias in the clustering amplitude S8σ8(ωm/0.3)0.5 due to uncertainties in the galaxy-halo connection is less than ∼50% of the statistical uncertainty of S8, unless the assembly biaseffect is unexpectedly large. Our best-fit models have S8=0.795-0.042+0.049 (mode and 68% credible interval) for the flat ΛCDM model; we find tighter constraints on the quantity S8(α=0.17)σ8(ωm/0.3)0.17=0.745-0.031+0.039.
  • Kenneth C. Wong, James H.H. Chan, Dani C.Y. Chao, Anton T. Jaelani, Issha Kayo, Chien Hsiu Lee, Anupreeta More, Masamune Oguri
    Publications of the Astronomical Society of Japan 74(5) 1209-1219 2022年10月1日  
    Abstract We conduct a search for galaxy-scale strong gravitational lens systems in Data Release 4 of the Hyper Suprime-Cam Subaru Strategic Program (HSC SSP), consisting of data taken up to the S21A semester. We select 103191 luminous red galaxies from the Baryon Oscillation Spectroscopic Survey (BOSS) sample that have deep multiband imaging from the HSC SSP and use the YattaLens algorithm to identify lens candidates with blue arc-like features automatically. The candidates are visually inspected and graded based on their likelihood of being a lens. We find eight definite lenses, 28 probable lenses, and 138 possible lenses. The new lens candidates generally have lens redshifts in the range 0.3 ≲ zL ≲ 0.9, a key intermediate redshift range to study the evolution of galaxy structure. Follow-up spectroscopy will confirm these new lenses and measure source redshifts to enable detailed lens modeling.
  • Masamune Oguri, Ryuichi Takahashi
    Physical Review D 106(4) 2022年8月15日  
    We discuss how small-scale density perturbations on the Fresnel scale affect amplitudes and phases of gravitational waves that are magnified by gravitational lensing in geometric optics. We derive equations that connect the small-scale density perturbations with the amplitude and phase fluctuations to show that such perturbative wave optics effects are significantly boosted in the presence of macro model magnifications such that amplitude and phase fluctuations can easily be observed for highly magnified gravitational waves. We discuss expected signals due to microlensing by stars, dark matter substructure, fuzzy dark matter, and primordial black holes.
  • Keiichi Umetsu, Shutaro Ueda, Bau Ching Hsieh, Mario Nonino, I. Non Chiu, Masamune Oguri, Sandor M. Molnar, Anton M. Koekemoer, Sut Ieng Tam
    Astrophysical Journal 934(2) 2022年8月1日  
    We present a detailed weak-lensing and X-ray study of the Frontier Fields galaxy cluster Abell 370, one of the most massive known lenses on the sky, using wide-field BR C z′ Subaru/Suprime-Cam and Chandra X-ray observations. By combining two-dimensional (2D) shear and azimuthally averaged magnification constraints derived from Subaru data, we perform a lensing mass reconstruction in a free-form manner, which allows us to determine both the radial structure and 2D morphology of the cluster mass distribution. In a triaxial framework assuming a Navarro-Frenk-White density profile, we constrain the intrinsic structure and geometry of the cluster halo by forward modeling the reconstructed mass map. We obtain a halo mass M 200 = (1.54 ± 0.29) ×1015 h −1 M ⊙, a halo concentration c 200 = 5.27 ± 1.28, and a minor-major axis ratio q a = 0.62 ± 0.23 with uninformative priors. Using a prior on the line-of-sight alignment of the halo major axis derived from binary merger simulations constrained by multi-probe observations, we find that the data favor a more prolate geometry with lower mass and lower concentration. From triaxial lens modeling with the line-of-sight prior, we find a spherically enclosed gas mass fraction of f gas = (8.4 ± 1.0)% at 0.7 h −1 Mpc ∼ 0.7r 500. When compared to the hydrostatic mass estimate (M HE) from Chandra observations, our triaxial weak-lensing analysis yields spherically enclosed mass ratios of 1 − b ≡ M HE/M WL = 0.56 ± 0.09 and 0.51 ± 0.09 at 0.7 h −1 Mpc with and without using the line-of-sight prior, respectively. Since the cluster is in a highly disturbed dynamical state, this represents the likely maximum level of hydrostatic bias in galaxy clusters.
  • Takashi Hamana, Chiaki Hikage, Masamune Oguri, Masato Shirasaki, Surhud More
    Publications of the Astronomical Society of Japan 74(4) 923-945 2022年8月1日  
    We perform a cosmic shear analysis of Hyper Suprime-Cam Subaru Strategic Program first-year data (HSC-Y1) using complete orthogonal sets of E/B-integrals (COSEBIs) to derive cosmological constraints. We compute E/B-mode COSEBIs from cosmic shear two-point correlation functions measured on an angular range of 4′ < θ < 180′. We perform a standard Bayesian likelihood analysis for cosmological inference from the measured E-mode COSEBIs, including contributions from intrinsic alignments of galaxies as well as systematic effects from point spread function model errors, shear calibration uncertainties, and source redshift distribution errors. We adopt a covariance matrix derived from realistic mock catalogs constructed from full-sky gravitational lensing simulations that fully take account of the survey geometry and measurement noise. For a flat Λ cold dark matter model, we find S8 ≡ σ8√Ω m/0.3 = 0.809-0.026+0.036. We carefully check the robustness of the cosmological results against astrophysical modeling uncertainties and systematic uncertainties in measurements, and find that none of them has a significant impact on the cosmological constraints. We also find that the measured B-mode COSEBIs are consistent with zero. We examine, using mock HSC-Y1 data, the consistency of our S8 constraints with those derived from the other cosmic shear two-point statistics, the power spectrum analysis by Hikage et al. (2019, PASJ, 71, 43) and the two-point correlation function analysis by Hamana et al. (2020, PASJ, 72, 16), which adopt the same HSC-Y1 shape catalog, and find that all the S8 constraints are consistent with each other, although the expected correlations between derived S8 constraints are weak.
  • Sunao Sugiyama, Masahiro Takada, Hironao Miyatake, Takahiro Nishimichi, Masato Shirasaki, Yosuke Kobayashi, Rachel Mandelbaum, Surhud More, Ryuichi Takahashi, Ken Osato, Masamune Oguri, Jean Coupon, Chiaki Hikage, Bau Ching Hsieh, Yutaka Komiyama, Alexie Leauthaud, Xiangchong Li, Wentao Luo, Robert H. Lupton, Hitoshi Murayama, Atsushi J. Nishizawa, Youngsoo Park, Paul A. Price, Melanie Simet, Joshua S. Speagle, Michael A. Strauss, Masayuki Tanaka
    Physical Review D 105(12) 2022年6月15日  
    We present cosmological parameter constraints from a blinded joint analysis of galaxy-galaxy weak lensing, Δς(R), and the projected correlation function, wp(R), measured from the first-year HSC (HSC-Y1) data and SDSS spectroscopic galaxies over 0.15<z<0.7. We use luminosity-limited samples as lens samples for Δς and as large-scale structure tracers for wp in three redshift bins, and use the HSC-Y1 galaxy catalog to define a secure sample of source galaxies at zph>0.75 for the Δς measurements, selected based on their photometric redshifts. As a theoretical template, we use the "minimal bias"model for the cosmological clustering observables for the flat ΛCDM cosmological model. We compare the model predictions with the measurements in each redshift bin on large scales, R>12 and 8h-1 Mpc for Δς(R) and wp(R), respectively, where the perturbation-theory-inspired model is valid. As part of our model, we account for the effect of lensing magnification bias on the Δς measurements. When we employ weak priors on cosmological parameters, without cosmic microwave background (CMB) information, we find S8=0.936-0.086+0.092, σ8=0.85-0.11+0.16, and ωm=0.283-0.035+0.12 (mode and 68% credible interval) for the flat ΛCDM model. Although the central value of S8 appears to be larger than those inferred from other cosmological experiments, we find that the difference is consistent with expected differences due to sample variance, and our results are consistent with the other results to within the statistical uncertainties. When combined with the Planck 2018 likelihood for the primary CMB anisotropy information (TT,TE,EE+lowE), we find S8=0.817-0.021+0.022, σ8=0.892-0.056+0.051, ωm=0.246-0.035+0.045, and the equation-of-state parameter of dark energy, wde=-1.28-0.19+0.20 for the flat wCDM model, which is consistent with the flat ΛCDM model to within the error bars.
  • Fengwu Sun, Eiichi Egami, Seiji Fujimoto, Timothy Rawle, Franz E. Bauer, Kotaro Kohno, Ian Smail, Pablo G. Pérez-González, Yiping Ao, Scott C. Chapman, Francoise Combes, Miroslava Dessauges-Zavadsky, Daniel Espada, Jorge González-López, Anton M. Koekemoer, Vasily Kokorev, Minju M. Lee, Kana Morokuma-Matsui, Alejandra M. Muñoz Arancibia, Masamune Oguri, Roser Pelló, Yoshihiro Ueda, Ryosuke Uematsu, Francesco Valentino, Paul Van Der Werf, Gregory L. Walth, Michael Zemcov, Adi Zitrin
    Astrophysical Journal 932(2) 2022年6月1日  
    We present an ALMA-Herschel joint analysis of sources detected by the ALMA Lensing Cluster Survey (ALCS) at 1.15 mm. Herschel/PACS and SPIRE data at 100-500 μm are deblended for 180 ALMA sources in 33 lensing cluster fields that are detected either securely (141 sources; in our main sample) or tentatively at S/N ≥ 4 with cross-matched HST/Spitzer counterparts, down to a delensed 1.15 mm flux density of ∼0.02 mJy. We performed far-infrared spectral energy distribution modeling and derived the physical properties of dusty star formation for 125 sources (109 independently) that are detected at >2σ in at least one Herschel band. A total of 27 secure ALCS sources are not detected in any Herschel bands, including 17 optical/near-IR-dark sources that likely reside at z = 4.2 ± 1.2. The 16th, 50th, and 84th percentiles of the redshift distribution are 1.15, 2.08, and 3.59, respectively, for ALCS sources in the main sample, suggesting an increasing fraction of z ≃ 1 - 2 galaxies among fainter millimeter sources (f 1150 ∼0.1 mJy). With a median lensing magnification factor of μ=2.6-0.8+2.6, ALCS sources in the main sample exhibit a median intrinsic star formation rate of 94-54+84 M ⊙ yr-1, lower than that of conventional submillimeter galaxies at similar redshifts by a factor of ∼3. Our study suggests weak or no redshift evolution of dust temperature with L IR < 1012 L ⊙ galaxies within our sample at z ≃ 0 - 2. At L IR > 1012 L ⊙, the dust temperatures show no evolution across z ≃ 1-4 while being lower than those in the local universe. For the highest-redshift source in our sample (z = 6.07), we can rule out an extreme dust temperature (>80 K) that was reported for MACS0416 Y1 at z = 8.31.
  • M. E. Ramos-Ceja, M. Oguri, S. Miyazaki, V. Ghirardini, I. Chiu, N. Okabe, A. Liu, T. Schrabback, D. Akino, Y. E. Bahar, E. Bulbul, N. Clerc, J. Comparat, S. Grandis, M. Klein, Y. T. Lin, A. Merloni, I. Mitsuishi, H. Miyatake, S. More, K. Nandra, A. J. Nishizawa, N. Ota, F. Pacaud, T. H. Reiprich, J. S. Sanders
    Astronomy and Astrophysics 661 2022年5月1日  
    Context. The eFEDS survey is a proof-of-concept mini-survey designed to demonstrate the survey science capabilities of SRG/eROSITA. It covers an area of 140 deg2 where ~540 galaxy clusters have been detected out to a redshift of 1.3. The eFEDS field is partly embedded in the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) S19A data release, which covers ~510 deg2, containing approximately 36 million galaxies. This galaxy catalogue has been used to construct a sample of ~180 shear-selected galaxy clusters. The common area to both surveys covers about 90 deg2, making it an ideal region to study galaxy clusters selected in different ways. Aims. The aim of this work is to investigate the effects of selection methods in the galaxy cluster detection by comparing the X-ray selected, eFEDS, and the shear-selected, HSC-SSP S19A, galaxy cluster samples. There are 25 shear-selected clusters in the eFEDS fooprint. Methods. The relation between X-ray bolometric luminosity and weak-lensing mass is investigated (Lbol - M relation), comparing this relation derived from a shear-selected cluster sample to the relation obtained from an X-ray selected sample. Moreover, the dynamical state of the shear-selected clusters is investigated and compared to the X-ray selected sample using X-ray morphological parameters and galaxy distribution. Results. The normalisation of the Lbol â ? ? M relation of the X-ray selected and shear-selected samples is consistent within 1Ï ? -. Moreover, the dynamical state and merger fraction of the shear-selected clusters is not different from the X-ray selected ones. Four shear-selected clusters are undetected in X-rays. A close inspection reveals that one is the result of projection effects, while the other three have an X-ray flux below the ultimate eROSITA detection limit. Finally, 43% of the shear-selected clusters lie in superclusters. Conclusions. Our results indicate that the scaling relation between X-ray bolometric luminosity and true cluster mass of the shear-selected cluster sample is consistent with the eFEDS sample. There is no significant population of X-ray underluminous clusters, indicating that X-ray selected cluster samples are complete and can be used as an accurate cosmological probe.
  • A. Liu, E. Bulbul, V. Ghirardini, T. Liu, M. Klein, N. Clerc, Y. Özsoy, M. E. Ramos-Ceja, F. Pacaud, J. Comparat, N. Okabe, Y. E. Bahar, V. Biffi, H. Brunner, M. Brüggen, J. Buchner, J. Ider Chitham, I. Chiu, K. Dolag, E. Gatuzz, J. Gonzalez, D. N. Hoang, G. Lamer, A. Merloni, K. Nandra, M. Oguri, N. Ota, P. Predehl, T. H. Reiprich, M. Salvato, T. Schrabback, J. S. Sanders, R. Seppi, Q. Thibaud
    Astronomy and Astrophysics 661 2022年5月1日  
    Aims. The eROSITA Final Equatorial-Depth Survey has been carried out during the performance verification phase of the Spectrum- Roentgen-Gamma/eROSITA telescope and was completed in November 2019. This survey is designed to provide the first eROSITAselected sample of clusters and groups and to test the predictions for the all-sky survey in the context of cosmological studies with clusters of galaxies. Methods. In the area of 140 square degrees covered by eFEDS, 542 candidate clusters and groups of galaxies were detected as extended X-ray sources with the eSASS source detection algorithm. We performed imaging and spectral analysis of the 542 cluster candidates with eROSITA X-ray data and studied the properties of the sample. Results. We provide the catalog of candidate galaxy clusters and groups detected by eROSITA in the eFEDS field down to a flux of 10-14 erg s1 cm2 in the soft band (0.5–2 keV) within 10. The clusters are distributed in the redshift range z = [0.01, 1.3] with a median redshift zmedian = 0:35. With eROSITA X-ray data, we measured the temperature of the intracluster medium within two radii, 300 kpc and 500 kpc, and constrained the temperature with > confidence level for 1=5 (102 out of 542) of the sample. The average temperature of these clusters is2 keV. Radial profiles of flux, luminosity, electron density, and gas mass were measured from the precise modeling of the imaging data. The selection function, the purity, and the completeness of the catalog are examined and discussed in detail. The contamination fraction is 1=5 in this sample and is dominated by misidentified point sources. The X-ray luminosity function of the clusters agrees well with the results obtained from other recent X-ray surveys. We also find 19 supercluster candidates in this field, most of which are located at redshifts between 0.1 and 0.5, including one cluster at z0:36 that was presented previously. Conclusions. The eFEDS cluster and group catalog at the final eRASS equatorial depth provides a benchmark proof of concept for the eROSITA All-Sky Survey extended source detection and characterization. We confirm the excellent performance of eROSITA for cluster science and expect no significant deviations from our pre-launch expectations for the final all-sky survey.
  • M. Klein, M. Oguri, J. J. Mohr, S. Grandis, V. Ghirardini, T. Liu, A. Liu, E. Bulbul, J. Wolf, J. Comparat, M. E. Ramos-Ceja, J. Buchner, I. Chiu, N. Clerc, A. Merloni, H. Miyatake, S. Miyazaki, N. Okabe, N. Ota, F. Pacaud, M. Salvato, S. P. Driver
    Astronomy and Astrophysics 661 2022年5月1日  
    Context. In 2019, the eROSITA telescope on board the Russian-German satellite Spectrum-Roentgen-Gamma (SRG) began to perform a deep all-sky X-ray survey with the aim of identifying ~100 000 clusters and groups over the course of four years. As part of its performance verification phase, a ~140 deg2 survey, called eROSITA Final Equatorial-Depth Survey (eFEDS), was performed. With a depth typical of the all-sky survey after four years, it allows tests of tools and methods as well as improved predictions for the all-sky survey. Aims. As part of this effort, a catalog of 542 X-ray selected galaxy group and cluster candidates was compiled. In this paper we present the optical follow-up, with the aim of providing redshifts and cluster confirmation for the full sample. Furthermore, we aim to provide additional information on the dynamical state, richness, and optical center of the clusters. Finally, we aim to evaluate the impact of optical cluster confirmation on the purity and completeness of the X-ray selected sample. Methods. We used optical imaging data from the Hyper Suprime-Cam Subaru Strategic Program and from the Legacy Survey to identify optical counterparts to the X-ray detected cluster candidates. We make use of the multi-component matched filter cluster confirmation tool (MCMF), as well as of the optical cluster finder CAMIRA to derive cluster redshifts and richnesses. MCMF provided the probabilities with which an optical structure would be a chance superposition with the X-ray candidate. These probabilities were used to identify the best optical counterpart as well as to confirm an X-ray candidate as a cluster. The impact of this confirmation process on catalog purity and completeness was estimated using optical to X-ray scaling relations as well as simulations. The resulting catalog was furthermore matched with public group and cluster catalogs. Optical estimators of the cluster dynamical state were constructed based on density maps of the red-sequence galaxies at the cluster redshift. Results. By providing redshift estimates for all 542 candidates, we construct an optically confirmed sample of 477 clusters and groups with a residual contamination of 6%. Of these, 470 (98.5%) are confirmed using MCMF, and 7 systems are added through cross-matching with spectroscopic group catalogs. Using observable-to-observable scaling and the applied confirmation threshold, we predict that 8 ± 2 real systems have been excluded with the MCMF cut required to build this low-contamination sample. This number agrees well with the 7 systems found through cross-matching that were not confirmed with MCMF. The predicted redshift and mass distribution of this catalog agree well with simulations. Thus, we expect that these 477 systems include >99% of all true clusters in the candidate list. Using an MCMF-independent method, we confirm that the catalog contamination of the confirmed subsample is 6 ± 3%. Application of the same method to the full candidate list yields 17 ± 3%, consistent with estimates coming from the fraction of confirmed systems of ~17% and with expectations from simulations of ~20%. We also present a sample of merging cluster candidates based on the derived estimators of the cluster dynamical state.
  • I-Non Chiu, Vittorio Ghirardini, Ang Liu, Sebastian Grandis, Esra Bulbul, Y. Emre Bahar, Johan Comparat, Sebastian Bocquet, Nicolas Clerc, Matthias Klein, Teng Liu, Xiangchong Li, Hironao Miyatake, Joseph Mohr, Surhud More, Masamune Oguri, Nobuhiro Okabe, Florian Pacaud, Miriam E. Ramos-Ceja, Thomas H. Reiprich, Tim Schrabback, Keiichi Umetsu
    ASTRONOMY & ASTROPHYSICS 661 2022年5月  
    We present the first weak-lensing mass calibration and X-ray scaling relations of galaxy clusters and groups selected in the eROSITA Final Equatorial Depth Survey (eFEDS) observed by Spectrum Roentgen Gamma/eROSITA over a contiguous footprint with an area of approximate to 140 deg(2), using the three-year (S19A) weak-lensing data from the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. In this work, we study a sample of 434 optically confirmed galaxy clusters (and groups) at redshift 0.01 less than or similar to z less than or similar to 1.3 with a median of 0.35, of which 313 systems are uniformly covered by the HSC survey to enable the extraction of the weak-lensing shear observable. In a Bayesian population modeling, we perform a blind analysis for the weak-lensing mass calibration by simultaneously modeling the observed count rate eta and the shear profile g(+) of individual clusters through the count-rate-to-mass-and-redshift (eta-M-500-z) relation and the weak-lensing-mass-to-mass-and-redshift (M-WL-M-500-z) relation, respectively, while accounting for the bias in these observables using simulation-based calibrations. As a result, the count-rate-inferred and lensing-calibrated cluster mass is obtained from the joint modeling of the scaling relations, as the ensemble mass spanning a range of 10(13)h(-1)M(circle dot) less than or similar to M-500 less than or similar to 10(15)h(-1)M(circle dot) with a median of approximate to 10(14)h(-1)M(circle dot) for the eFEDS sample. With the mass calibration, we further model the X-ray observable-to-mass-and-redshift relations, including the rest-frame soft-band and bolometric luminosity (L-X and L-b), the emission-weighted temperature T-X, the mass of intra-cluster medium M-g, and the mass proxy Y-X, which is the product of T-X and M-g. Except for L-X with a steeper dependence on the cluster mass at a statistically significant level, we find that the other X-ray scaling relations all show a mass trend that is statistically consistent with the self-similar prediction at a level of less than or similar to 1.7 sigma. Meanwhile, all these scaling relations show no significant deviation from the self-similarity in their redshift scaling. Moreover, no significant redshift-dependent mass trend is present. This work demonstrates the synergy between the eROSITA and HSC surveys in preparation for the forthcoming first-year eROSITA cluster cosmology.
  • Takashi Hamana, Masato Shirasaki, Satoshi Miyazaki, Chiaki Hikage, Masamune Oguri, Surhud More, Robert Armstrong, Alexie Leauthaud, Rachel Mandelbaum, Hironao Miyatake, Atsushi J. Nishizawa, Melanie Simet, Masahiro Takada, Hiroaki Aihara, James Bosch, Yutaka Komiyama, Robert Lupton, Hitoshi Murayama, Michael A. Strauss, Masayuki Tanaka
    Publications of the Astronomical Society of Japan 74(2) 488-491 2022年4月  
    In the original publication of "Cosmological constraints from cosmic shear two-point correlation functions with HSC survey first-year data"[PASJ, 72, 16 (2020); doi: 10.1093/pasj/psz138], we discovered a couple of bugs in the software used for numerical computations. Here we present revised results obtained from corrected computations.
  • Hiroaki Aihara, Yusra Alsayyad, Makoto Ando, Robert Armstrong, James Bosch, Eiichi Egami, Hisanori Furusawa, Junko Furusawa, Sumiko Harasawa, Yuichi Harikane, Bau Ching Hsieh, Hiroyuki Ikeda, Kei Ito, Ikuru Iwata, Tadayuki Kodama, Michitaro Koike, Mitsuru Kokubo, Yutaka Komiyama, Xiangchong Li, Yongming Liang, Yen Ting Lin, Robert H. Lupton, Nate B. Lust, Lauren A. Macarthur, Ken Mawatari, Sogo Mineo, Hironao Miyatake, Satoshi Miyazaki, Surhud More, Takahiro Morishima, Hitoshi Murayama, Kimihiko Nakajima, Fumiaki Nakata, Atsushi J. Nishizawa, Masamune Oguri, Nobuhiro Okabe, Yuki Okura, Yoshiaki Ono, Ken Osato, Masami Ouchi, Yen Chen Pan, Andres A. Plazas Malagon, Paul A. Price, Sophie L. Reed, Eli S. Rykoff, Takatoshi Shibuya, Mirko Simunovic, Michael A. Strauss, Kanako Sugimori, Yasushi Suto, Nao Suzuki, Masahiro Takada, Yuhei Takagi, Tadafumi Takata, Satoshi Takita, Masayuki Tanaka, Shenli Tang, Dan S. Taranu, Tsuyoshi Terai, Yoshiki Toba, Edwin L. Turner, Hisakazu Uchiyama, Bovornpratch Vijarnwannaluk, Christopher Z. Waters, Yoshihiko Yamada, Naoaki Yamamoto, Takuji Yamashita
    Publications of the Astronomical Society of Japan 74(2) 247-272 2022年4月  
    This paper presents the third data release of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP), a wide-field multi-band imaging survey with the Subaru 8.2 m telescope. HSC-SSP has three survey layers (Wide, Deep, and UltraDeep) with different area coverages and depths, designed to address a wide array of astrophysical questions. This third release from HSC-SSP includes data from 278 nights of observing time and covers about 670 deg2 in all five broad-band filters (grizy) at the full depth (∼26 mag at 5σ depending on filter) in the Wide layer. If we include partially observed areas, the release covers 1470 deg2. The Deep and UltraDeep layers have ∼ 80% of the originally planned integration times, and are considered done, as we have slightly changed the observing strategy in order to compensate for various time losses. There are a number of updates in the image processing pipeline. Of particular importance is the change in the sky subtraction algorithm; we subtract the sky on small scales before the detection and measurement stages, which has significantly reduced the number of false detections. Thanks to this and other updates, the overall quality of the processed data has improved since the previous release. However, there are limitations in the data (for example, the pipeline is not optimized for crowded fields), and we encourage the user to check the quality assurance plots as well as a list of known issues before exploiting the data.
  • Xiangchong Li, Hironao Miyatake, Wentao Luo, Surhud More, Masamune Oguri, Takashi Hamana, Rachel Mandelbaum, Masato Shirasaki, Masahiro Takada, Robert Armstrong, Arun Kannawadi, Satoshi Takita, Satoshi Miyazaki, Atsushi J. Nishizawa, Andres A. Plazas Malagon, Michael A. Strauss, Masayuki Tanaka, Naoki Yoshida
    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 74(2) 421-459 2022年4月  
    We present the galaxy shear catalog that will be used for the three-year cosmological weak gravitational lensing analyses using data from the Wide layer of the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP) Survey. The galaxy shapes are measured from the i-band imaging data acquired from 2014 to 2019 and calibrated with image simulations that resemble the observing conditions of the survey based on training galaxy images from the Hubble Space Telescope in the COSMOS region. The catalog covers an area of 433.48 deg(2) of the northern sky, split into six fields. The mean i-band seeing is 0 ''.59. With conservative galaxy selection criteria (e.g., i-band magnitude brighter than 24.5), the observed raw galaxy number density is 22.9 arcmin(-2), and the effective galaxy number density is 19.9 arcmin(-2). The calibration removes the galaxy property-dependent shear estimation bias to the level vertical bar delta m vertical bar < 9 x 10(-3). The bias residual delta m shows no dependence on redshift in the range 0 < z <= 3. We define the requirements for cosmological weak-lensing science for this shear catalog, and quantify potential systematics in the catalog using a series of internal null tests for systematics related to point-spread function modelling and shear estimation. A variety of the null tests are statistically consistent with zero or within requirements, but (i) there is evidence for PSF model shape residual correlations; and (ii) star-galaxy shape correlations reveal additive systematics. Both effects become significant on >1 degrees scales and will require mitigation during the inference of cosmological parameters using cosmic shear measurements.
  • Brian Welch, Dan Coe, Jose M. Diego, Adi Zitrin, Erik Zackrisson, Paola Dimauro, Yolanda Jiménez-Teja, Patrick Kelly, Guillaume Mahler, Masamune Oguri, F. X. Timmes, Rogier Windhorst, Michael Florian, S. E. de Mink, Roberto J. Avila, Jay Anderson, Larry Bradley, Keren Sharon, Anton Vikaeus, Stephan McCandliss, Maruša Bradač, Jane Rigby, Brenda Frye, Sune Toft, Victoria Strait, Michele Trenti, Soniya Sharma, Felipe Andrade-Santos, Tom Broadhurst
    Nature 603(7903) 815-818 2022年3月31日  
    Galaxy clusters magnify background objects through strong gravitational lensing. Typical magnifications for lensed galaxies are factors of a few but can also be as high as tens or hundreds, stretching galaxies into giant arcs1,2. Individual stars can attain even higher magnifications given fortuitous alignment with the lensing cluster. Recently, several individual stars at redshifts between approximately 1 and 1.5 have been discovered, magnified by factors of thousands, temporarily boosted by microlensing3–6. Here we report observations of a more distant and persistent magnified star at a redshift of 6.2 ± 0.1, 900 million years after the Big Bang. This star is magnified by a factor of thousands by the foreground galaxy cluster lens WHL0137–08 (redshift 0.566), as estimated by four independent lens models. Unlike previous lensed stars, the magnification and observed brightness (AB magnitude, 27.2) have remained roughly constant over 3.5 years of imaging and follow-up. The delensed absolute UV magnitude, −10 ± 2, is consistent with a star of mass greater than 50 times the mass of the Sun. Confirmation and spectral classification are forthcoming from approved observations with the James Webb Space Telescope.
  • Rana Misato, Yoshiki Toba, Naomi Ota, Naoaki Yamamoto, Tadayuki Kodama, Nobuhiro Okabe, Masamune Oguri, Ikuyuki Mitsuishi
    Publications of the Astronomical Society of Japan 74(2) 398-406 2022年3月2日  査読有り
    We present herein a systematic X-ray analysis of blue galaxy clusters at z = 0.84 discovered by the Subaru telescope. The sample consisted of 43 clusters identified by combining red-sequence and blue-cloud surveys, covering a wide range of emitter fractions (i.e., 0.3-0.8). The spatial extent of the over-density region of emitter galaxies was approximately 1 Mpc in radius. The average cluster mass was estimated as 0.6(<1.5) × 1014 M⊙ from the stacked weak-lensing measurement. We analyzed the XMM-Newton archival data, and measured the X-ray luminosity of the hot intracluster medium. As a result, diffuse X-ray emission was marginally detected in 14 clusters, yielding an average luminosity of 5 × 1042 erg s-1. To the contrary, it was not significant in 29 clusters. The blue clusters were significantly fainter than the red-dominated clusters, and the X-ray luminosity did not show any meaningful correlation either with emitter fraction or richness. The X-ray surface brightness was low, but the amount of gas mass was estimated to be comparable to that observed in the 1013-1014 M⊙ cluster. Based on the results, we suggest that the blue clusters are at the early formation stage, and the gas is yet to be compressed and heated up to produce appreciable X-rays. Follow-up spectroscopic measurements are essential to clarify the dynamical status and co-evolution of galaxies and hot gas in the blue clusters.
  • Yoshiki Matsuoka, Kazushi Iwasawa, Masafusa Onoue, Takuma Izumi, Nobunari Kashikawa, Michael A. Strauss, Masatoshi Imanishi, Tohru Nagao, Masayuki Akiyama, John D. Silverman, Naoko Asami, James Bosch, Hisanori Furusawa, Tomotsugu Goto, James E. Gunn, Yuichi Harikane, Hiroyuki Ikeda, Rikako Ishimoto, Toshihiro Kawaguchi, Nanako Kato, Satoshi Kikuta, Kotaro Kohno, Yutaka Komiyama, Chien Hsiu Lee, Robert H. Lupton, Takeo Minezaki, Satoshi Miyazaki, Hitoshi Murayama, Atsushi J. Nishizawa, Masamune Oguri, Yoshiaki Ono, Masami Ouchi, Paul A. Price, Hiroaki Sameshima, Naoshi Sugiyama, Philip J. Tait, Masahiro Takada, Ayumi Takahashi, Tadafumi Takata, Masayuki Tanaka, Yoshiki Toba, Yousuke Utsumi, Shiang Yu Wang, Takuji Yamashita
    Astrophysical Journal, Supplement Series 259(1) 2022年3月  
    We present the spectroscopic discovery of 69 quasars at 5.8 < z < 7.0, drawn from the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP) imaging survey data. This is the 16th publication from the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, and it completes identification of all but the faintest candidates (i.e., i-band dropouts with z AB < 24 and y-band detections, and z-band dropouts with y AB < 24) with Bayesian quasar probability PQB>0.1 in the HSC-SSP third public data release (PDR3). The sample reported here also includes three quasars with PQB<0.1 at z ∼6.6, which we selected in an effort to completely cover the reddest point sources with simple color cuts. The number of high-z quasars discovered in SHELLQs has now grown to 162, including 23 type II quasar candidates. This paper also presents identification of seven galaxies at 5.6 < z < 6.7, an [O iii] emitter at z = 0.954, and 31 Galactic cool stars and brown dwarfs. High-z quasars and galaxies compose 75% and 16%, respectively, of all the spectroscopic SHELLQs objects that pass our latest selection algorithm with the PDR3 photometry. That is, a total of 91% of the objects lie at z > 5.6. This demonstrates that the algorithm has very high efficiency, even though we are probing an unprecedentedly low luminosity population down to M 1450 ∼-21 mag.
  • Hung Yu Jian, Lihwai Lin, Bau Ching Hsieh, Kai Yang Lin, Keiichi Umetsu, Carlos Lopez-Coba, Yusei Koyama, Chin Hao Hsu, Yung Chau Su, Yu Yen Chang, Tadayuki Kodama, Yutaka Komiyama, Surhud More, Atsushi J. Nishizawa, Masamune Oguri, Ichi Tanaka
    Astrophysical Journal 926(2) 2022年2月1日  
    We utilize the Hyper Suprime-Cam (HSC) Wide Survey to explore the properties of galaxies located in the voids identified from the Baryon Oscillation Spectroscopic Survey up to z ∼0.7. The HSC reaches i ∼25, allowing us to characterize the void galaxies down to 109.2 solar mass. We find that the revised void galaxy densities, when including faint galaxies in voids defined by bright galaxies, are still underdense compared to the mean density from the entire field. In addition, we classify galaxies into star-forming, quiescent, and green valley populations, and find that void galaxies tend to have slightly higher fractions of star-forming galaxies under the mass and redshift control, although the significance of this result is only moderate (2σ). However, when we focus on the star-forming population, the distribution of the specific star formation rate (sSFR) of void galaxies shows little difference from that of the control galaxies. Similarly, the median sSFR of star-forming void galaxies is also in good agreement with that of the star-forming control galaxies. Moreover, the effective green valley fraction of void galaxies, defined as the number of green valley galaxies over the number of nonquiescent galaxies, is comparable to that of the control ones, supporting the suggestion that void and control galaxies evolve under similar physical processes and quenching frequencies. Our results thus favor a scenario of galaxy assembly bias.
  • Daichi Akino, Dominique Eckert, Nobuhiro Okabe, Mauro Sereno, Keiichi Umetsu, Masamune Oguri, Fabio Gastaldello, I. Non Chiu, Stefano Ettori, August E. Evrard, Arya Farahi, Ben Maughan, Marguerite Pierre, Marina Ricci, Ivan Valtchanov, Ian Mccarthy, Sean Mcgee, Satoshi Miyazaki, Atsushi J. Nishizawa, Masayuki Tanaka
    Publications of the Astronomical Society of Japan 74(1) 175-208 2022年2月1日  
    We present our determination of the baryon budget for an X-ray-selected XXL sample of 136 galaxy groups and clusters spanning nearly two orders of magnitude in mass (M500 ∼1013-1015 M⊙) and the redshift range 0 ≲ z ≲ 1. Our joint analysis is based on the combination of Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) weak-lensing mass measurements, XXL X-ray gas mass measurements, and HSC and Sloan Digital Sky Survey multiband photometry. We carry out a Bayesian analysis of multivariate mass-scaling relations of gas mass, galaxy stellar mass, stellar mass of brightest cluster galaxies (BCGs), and soft-band X-ray luminosity, by taking into account the intrinsic covariance between cluster properties, selection effect, weak-lensing mass calibration, and observational error covariance matrix. The mass-dependent slope of the gas mass-total mass (M500) relation is found to be 1.29-0.10+0.16, which is steeper than the self-similar prediction of unity, whereas the slope of the stellar mass-total mass relation is shallower than unity; 0.85-0.09+0.12. The BCG stellar mass weakly depends on cluster mass with a slope of 0.49-0.10+0.11. The baryon, gas mass, and stellar mass fractions as a function of M500 agree with the results from numerical simulations and previous observations. We successfully constrain the full intrinsic covariance of the baryonic contents. The BCG stellar mass shows the larger intrinsic scatter at a given halo total mass, followed in order by stellar mass and gas mass. We find a significant positive intrinsic correlation coefficient between total (and satellite) stellar mass and BCG stellar mass and no evidence for intrinsic correlation between gas mass and stellar mass. All the baryonic components show no redshift evolution.
  • Hiroki Kawai, Masamune Oguri, Alfred Amruth, Tom Broadhurst, Jeremy Lim
    Astrophysical Journal 925(1) 2022年1月1日  
    Fuzzy dark matter (FDM), a scalar particle coupled to the gravitational field without self-interaction, whose mass range is m ∼10-24-10-20 eV, is one of the promising alternative dark matter candidates to cold dark matter. The quantum interference pattern, which is a unique structure of FDM, can be seen in halos in cosmological FDM simulations. In this paper, we first provide an analytic model of the subgalactic matter power spectrum originating from quantum clumps in FDM halos, in which the density distribution of the FDM is expressed by a superposition of quantum clumps whose size corresponds to the de Broglie wavelength of the FDM. These clumps are assumed to be distributed randomly, such that the ensemble average density follows a halo profile such as the Navarro-Frenk-White profile. We then compare the convergence power spectrum projected along the line of sight around the Einstein radius, which is converted from the subgalactic matter power spectrum, to that measured in the strong lens system SDSS J0252 + 0039. While we find that the current observation provides no useful constraint on the FDM mass, we show that future deep, high spatial resolution observations of strong lens systems can tightly constrain FDM with a mass around 10-22 eV.
  • Shogo Ishikawa, Teppei Okumura, Masamune Oguri, Sheng Chieh Lin
    Astrophysical Journal 922(1) 2021年11月20日  
    We present the clustering analysis of photometric luminous red galaxies (LRGs) at a redshift range of 0.1 ≤ z ≤ 1.05 using 615,317 photometric LRGs selected from the Hyper Suprime-Cam Subaru Strategic Program, covering ∼124 deg2. Our sample covers a broad range of stellar masses and photometric redshifts and enables a halo occupation distribution analysis to study the redshift and stellar-mass dependence of dark halo properties of LRGs. We find a tight correlation between the characteristic dark halo mass to host central LRGs, Mmin, and the number density of LRGs, independently of redshifts, indicating that the formation of LRGs is associated with the global environment. The Mmin of LRGs depends only weakly on the stellar mass M∗ at M∗ ≲ 1010.75 h-2 M⊙ at 0.3 < z < 1.05, in contrast to the case for all photometrically selected galaxies, for which Mmin shows significant dependence on M∗ even at low M∗. The weak stellar-mass dependence is indicative of the dark halo mass being the key parameter for the formation of LRGs, rather than the stellar mass. Our result suggests that the halo mass of ∼1012.5±0.2 h-1 M⊙ is the critical mass for an efficient halo quenching due to the halo environment. We compare our result with the result of the hydrodynamical simulation to find that low-mass LRGs at z ∼ 1 will increase their stellar masses by an order of magnitude from z = 1 to 0 through mergers and satellite accretions, and that a large fraction of massive LRGs at z < 0.9 consist of LRGs that recently migrated from massive green valley galaxies or those that evolved from less massive LRGs through mergers and satellite accretions.
  • Shenli Tang, John D. Silverman, Xuheng Ding, Junyao Li, Khee Gan Lee, Michael A. Strauss, Andy Goulding, Malte Schramm, Lalitwadee Kawinwanichakij, J. Xavier Prochaska, Joseph F. Hennawi, Masatoshi Imanishi, Kazushi Iwasawa, Yoshiki Toba, Issha Kayo, Masamune Oguri, Yoshiki Matsuoka, Masafusa Onoue, Knud Jahnke, Kohei Ichikawa, Tilman Hartwig, Nobunari Kashikawa, Toshihiro Kawaguchi, Kotaro Kohno, Yuichi Matsuda, Tohru Nagao, Yoshiaki Ono, Masami Ouchi, Kazuhiro Shimasaku, Hyewon Suh, Nao Suzuki, Yoshiaki Taniguchi, Yoshihiro Ueda, Naoki Yasuda
    Astrophysical Journal 922(1) 2021年11月20日  
    We report on a spectroscopic program to search for dual quasars using Subaru Hyper Suprime-Cam (HSC) images of SDSS quasars, which represent an important stage during galaxy mergers. Using Subaru/FOCAS and Gemini-N/GMOS, we identify three new physically associated quasar pairs having projected separations less than 20 kpc, out of 26 observed candidates. These include the discovery of the highest-redshift (z = 3.1) quasar pair with a separation <10 kpc. Based on the sample acquired to date, the success rate of identifying physically associated dual quasars is 19% when excluding stars based on their HSC colors. Using the full sample of six spectroscopically confirmed dual quasars, including three previously published, we find that the black holes in these systems have black hole masses (M BH ∼ 108-9 M o˙), bolometric luminosities (log L bol ∼ 44.5-47.5 erg s-1) and Eddington ratios (0.01-0.3) similar to single SDSS quasars. We measure the stellar mass of their host galaxies based on 2D image decomposition of the five-band (grizy) optical emission and assess the mass relation between supermassive black holes (SMBHs) and their hosts. Dual SMBHs appear to have elevated masses relative to their host galaxies. Thus, mergers may not necessarily align such systems onto the local mass relation, as suggested by the Horizon-AGN simulation. This study suggests that dual luminous quasars are triggered by mergers prior to the final coalescence of the two SMBHs, resulting in early mass growth of the black holes relative to their host galaxies.
  • Roohi Dalal, Michael A. Strauss, Tomomi Sunayama, Masamune Oguri, Yen Ting Lin, Song Huang, Youngsoo Park, Masahiro Takada
    Monthly Notices of the Royal Astronomical Society 507(3) 4016-4029 2021年11月1日  
    We study brightest cluster galaxies (BCGs) in ∼5000 galaxy clusters from the Hyper Suprime-Cam (HSC) Subaru Strategic Program. The sample is selected over an area of 830 deg2 and is uniformly distributed in redshift over the range of z = 0.3-1.0. The clusters have stellar masses in the range of 1011.8-1012.9M⊙. We compare the stellar mass of the BCGs in each cluster to what we would expect if their masses were drawn from the mass distribution of the other member galaxies of the clusters. The BCGs are found to be 'special', in the sense that they are not consistent with being a statistical extreme of the mass distribution of other cluster galaxies. This result is robust over the full range of cluster stellar masses and redshifts in the sample, indicating that BCGs are special up to a redshift of z = 1.0. However, BCGs with a large separation from the centre of the cluster are found to be consistent with being statistical extremes of the cluster member mass distribution. We discuss the implications of these findings for BCG formation scenarios.
  • Masamune Oguri, Satoshi Miyazaki, Xiangchong Li, Wentao Luo, Ikuyuki Mitsuishi, Hironao Miyatake, Surhud More, Atsushi J. Nishizawa, Nobuhiro Okabe, Naomi Ota, Andrés A. Plazas Malagón, Yousuke Utsumi
    Publications of the Astronomical Society of Japan 73(4) 817-829 2021年8月1日  
    We use the Hyper Suprime-Cam Subaru Strategic Program S19A shape catalog to construct weak lensing shear-selected cluster samples. From aperture mass maps covering ∼510 deg2 created using a truncated Gaussian filter, we construct a catalog of 187 shear-selected clusters that correspond to mass map peaks with signal-to-noise ratio larger than 4.7. Most of the shear-selected clusters have counterparts in optically selected clusters, from which we estimate the purity of the catalog to be higher than 95%. The sample can be expanded to 418 shear-selected clusters with the same signal-to-noise ratio cut by optimizing the shape of the filter function and by combining weak lensing mass maps created with several different background galaxy selections. We argue that dilution and obscuration effects of cluster member galaxies can be mitigated by using background source galaxy samples and adopting a filter function with its inner boundary larger than about 2'. The large samples of shear-selected clusters that are selected without relying on any baryonic tracer are useful for detailed studies of cluster astrophysics and cosmology.
  • Xiangchong Li, Naoki Yoshida, Masamune Oguri, Shiro Ikeda, Wentao Luo
    Astrophysical Journal 916(2) 2021年8月1日  
    We propose a novel method to reconstruct high-resolution three-dimensional mass maps using data from photometric weak-lensing surveys. We apply an adaptive LASSO algorithm to perform a sparsity-based reconstruction on the assumption that the underlying cosmic density field is represented by a sum of Navarro-Frenk-White halos. We generate realistic mock galaxy shear catalogs by considering the shear distortions from isolated halos for the configurations matched to the Subaru Hyper Suprime-Cam Survey with its photometric redshift estimates. We show that the adaptive method significantly reduces line-of-sight smearing that is caused by the correlation between the lensing kernels at different redshifts. Lensing clusters with lower mass limits of 1014.0 h-1 M o˙, 1014.7 h-1 M o˙, 1015.0 h-1 M o˙ can be detected with 1.5σ confidence at the low (z < 0.3), median (0.3 ≤ z < 0.6), and high (0.6 ≤ z < 0.85) redshifts, respectively, with an average false detection rate of 0.022 deg-2. The estimated redshifts of the detected clusters are systematically lower than the true values by Δz ∼ 0.03 for halos at z ≤ 0.4, but the relative redshift bias is below 0.5% for clusters at 0.4 < z ≤ 0.85. The standard deviation of the redshift estimation is 0.092. Our method enables direct three-dimensional cluster detection with accurate redshift estimates.
  • Masamune Oguri
    Publications of the Astronomical Society of the Pacific 133(1025) 2021年7月1日  
    We present a new approach for fast calculation of gravitational lensing properties, including the lens potential, deflection angles, convergence, and shear, of elliptical Navarro–Frenk–White (NFW) and Hernquist density profiles, by approximating them by superpositions of elliptical density profiles for which simple analytic expressions of gravitational lensing properties are available. This model achieves high fractional accuracy better than 10−4 in the range of the radius normalized by the scale radius of 10−4–103 . These new approximations are ∼300 times faster in solving the lens equation for a point source compared with the traditional approach resorting to expensive numerical integrations, and are implemented in glafic software.
  • N Laporte, A Zitrin, R S Ellis, S Fujimoto, G Brammer, J Richard, M Oguri, G B Caminha, K Kohno, Y Yoshimura, Y Ao, F E Bauer, K Caputi, E Egami, D Espada, J González-López, B Hatsukade, K K Knudsen, M M Lee, G Magdis, M Ouchi, F Valentino, T Wang
    Monthly Notices of the Royal Astronomical Society 505(4) 4838-4846 2021年6月29日  
    <title>ABSTRACT</title> We report the discovery of an intrinsically faint, quintuply-imaged, dusty galaxy MACS0600-z6 at a redshift z = 6.07 viewed through the cluster MACSJ0600.1–2008 (z = 0.46). A ≃ 4σ dust detection is seen at 1.2mm as part of the ALMA Lensing Cluster Survey (ALCS), an on-going ALMA Large programme, and the redshift is secured via [C ii] 158 μm emission described in a companion paper. In addition, spectroscopic follow-up with GMOS/Gemini-North shows a break in the galaxy’s spectrum, consistent with the Lyman break at that redshift. We use a detailed mass model of the cluster and infer a magnification μ ≳ 30 for the most magnified image of this galaxy, which provides an unprecedented opportunity to probe the physical properties of a sub-luminous galaxy at the end of cosmic reionization. Based on the spectral energy distribution, we infer lensing-corrected stellar and dust masses of $\rm {2.9^{+11.5}_{-2.3}\times 10^9}$ and $\rm {4.8^{+4.5}_{-3.4}\times 10^6}$$\rm {M_{\odot } }$, respectively, a star formation rate of $\rm {9.7^{+22.0}_{-6.6} \, M_{\odot } \, yr^{-1 } }$, an intrinsic size of $\rm {0.54^{+0.26}_{-0.14 } }$ kpc, and a luminosity-weighted age of 200 ± 100 Myr. Strikingly, the dust production rate in this relatively young galaxy appears to be larger than that observed for equivalent, lower redshift sources. We discuss if this implies that early supernovae are more efficient dust producers and the consequences for using dust mass as a probe of earlier star formation.
  • Keigo Tanaka, Ryuichi Fujimoto, Nobuhiro Okabe, Ikuyuki Mitsuishi, Hiroki Akamatsu, Naomi Ota, Masamune Oguri, Atsushi J. Nishizawa
    Publications of the Astronomical Society of Japan 73(3) 584-595 2021年6月  査読有り
    We represent a joint X-ray, weak-lensing, and optical analysis of the optically-selected merging cluster, HSC J085024+001536, from the Subaru HSC-SSP survey. Both the member galaxy density and the weak-lensing mass map show that the cluster is composed of southeast and northwest components. The two-dimensional weak-lensing analysis shows that the southeast component is the main cluster, and the sub- and main-cluster mass ratio is $0.32^{+0.75}_{-0.23}$. The northwest subcluster is offset by $\sim700$ kpc from the main cluster center, and their relative line-of-sight velocity is $\sim1300\,{\rm km s^{-1 } }$ from spectroscopic redshifts of member galaxies. The X-ray emission is concentrated around the main cluster, while the gas mass fraction within a sphere of $1'$ radius of the subcluster is only $f_{\mathrm{gas } }=4.0^{+2.3}_{-3.3}\%$, indicating that the subcluster gas was stripped by ram pressure. X-ray residual image shows three arc-like excess patterns, of which two are symmetrically located at $\sim550$ kpc from the X-ray morphological center, and the other is close to the X-ray core. The excess close to the subcluster has a cold-front feature where dense-cold gas and thin-hot gas contact. The two outer excesses are tangentially elongated about $\sim 450-650$ kpc, suggesting that the cluster is merged with a non-zero impact parameter. Overall features revealed by the multi-wavelength datasets indicate that the cluster is at the second impact or later. Since the optically-defined merger catalog is unbiased for merger boost of the intracluster medium, X-ray follow-up observations will pave the way to understand merger physics at various phases.
  • Ryoma Murata, Tomomi Sunayama, Masamune Oguri, Surhud More, Atsushi J. Nishizawa, Takahiro Nishimichi, Ken Osato
    Publications of the Astronomical Society of Japan 73(3) 772 2021年6月1日  
    In the original publication of this article [PASJ, 72, 64 (2020); doi: 10.1093/pasj/psaa041], figure 7 was erroneously inserted in the place of figure 8 during the production process. The PDF and HTML versions of the original article are updated with the correct image upon the publication of this erratum.
  • J. P. Willis, M. Oguri, M. E. Ramos-Ceja, F. Gastaldello, M. Sereno, C. Adami, S. Alis, B. Altieri, L. Chiappetti, P. S. Corasaniti, D. Eckert, S. Ettori, C. Garrel, P. Giles, J. Lefevre, L. Faccioli, S. Fotopoulou, A. Hamabata, E. Koulouridis, M. Lieu, Y. T. Lin, B. Maughan, A. J. Nishizawa, T. Okabe, N. Okabe, F. Pacaud, S. Paltani, M. Pierre, M. Plionis, B. Poggianti, E. Pompei, T. Sadibekova, K. Umetsu, P. Valageas
    Monthly Notices of the Royal Astronomical Society 503(4) 5624-5637 2021年6月1日  
    Large samples of galaxy clusters provide knowledge of both astrophysics in the most massive virialized environments and the properties of the cosmological model that defines our Universe. However, an important issue that affects the interpretation of galaxy cluster samples is the role played by the selection waveband and the potential for this to introduce a bias in the physical properties of clusters thus selected. We aim to investigate waveband-dependent selection effects in the identification of galaxy clusters by comparing the X-ray MultiMirror (XMM) Ultimate Extra-galactic Survey (XXL) and Subaru Hyper Suprime-Cam (HSC) CAMIRA cluster samples identified from a common 22.6 deg2 sky area. We compare 150 XXL and 270 CAMIRA clusters in a common parameter space defined by X-ray aperture brightness and optical richness. We find that 71/150 XXL clusters are matched to the location of a CAMIRA cluster, the majority of which (67/71) display richness values N > 15 that exceed the CAMIRA catalogue richness threshold. We find that 67/270 CAMIRA clusters are matched to the location of an XXL cluster (defined within XXL as an extended X-ray source). Of the unmatched CAMIRA clusters, the majority display low X-ray fluxes consistent with the lack of an XXL counterpart. However, a significant fraction (64/107) CAMIRA clusters that display high X-ray fluxes are not associated with an extended source in the XXL catalogue. We demonstrate that this disparity arises from a variety of effects including the morphological criteria employed to identify X-ray clusters and the properties of the XMM PSF.
  • Seiji Fujimoto, Masamune Oguri, Gabriel Brammer, Yuki Yoshimura, Nicolas Laporte, Jorge Gonzalez-Lopez, Gabriel B. Caminha, Kotaro Kohno, Adi Zitrin, Johan Richard, Masami Ouchi, Franz E. Bauer, Ian Smail, Bunyo Hatsukade, Yoshiaki Ono, Vasily Kokorev, Hideki Umehata, Daniel Schaerer, Kirsten Knudsen, Fengwu Sun, Georgios Magdis, Francesco Valentino, Yiping Ao, Sune Toft, Miroslava Dessauges-Zavadsky, Kazuhiro Shimasaku, Karina Caputi, Haruka Kusakabe, Kana Morokuma-Matsui, Kikuchihara Shotaro, Eiichi Egami, Minju M. Lee, Timothy Rawle, Daniel Espada
    ASTROPHYSICAL JOURNAL 911(2) 2021年4月  
    We present bright [C ii] 158 mu m line detections from a strongly magnified and multiply imaged (mu similar to 20-160) sub-L* (MUV=-19.75-0.44+0.55) Lyman-break galaxy (LBG) at z = 6.0719 +/- 0.0004, drawn from the ALMA Lensing Cluster Survey (ALCS). Emission lines are identified at 268.7 GHz at >= 8 sigma exactly at the positions of two multiple images of the LBG, behind the massive galaxy cluster RXCJ0600-2007. Our lens models, updated with the latest spectroscopy from VLT/MUSE, indicate that a sub region of the LBG crosses the caustic, and is lensed into a long (similar to 6 '') arc with a local magnification of mu similar to 160, for which the [C ii] line is also significantly detected. The source plane reconstruction resolves the interstellar medium (ISM) structure, showing that the [C ii] line is co-spatial with the rest-frame UV continuum at a scale of similar to 300 pc. The [C ii] line properties suggest that the LBG is a rotation-dominated system, whose velocity gradient explains a slight difference in redshifts between the whole LBG and its sub-region. The star formation rate (SFR)-L-[CII] relations, for whole and sub-regions of the LBG, are consistent with those of local galaxies. We evaluate the lower limit of the faint-end of the [C ii] luminosity function at z = 6, finding it to be consistent with predictions from semi-analytical models and from the local SFR-L-[CII] relation with a SFR function at z = 6. These results imply that the local SFR-L-[CII] relation is universal for a wide range of scales, including the spatially resolved ISM, the whole region of the galaxy, and the cosmic scale, even in the epoch of reionization.
  • Yue Shen, Yu-Ching Chen, Hsiang-Chih Hwang, Xin Liu, Nadia Zakamska, Masamune Oguri, Jennifer I-Hsiu Li, Joseph Lazio, Peter Breiding
    NATURE ASTRONOMY 5(6) 569-574 2021年4月  
    Galaxy mergers occur frequently in the early Universe(1) and bring multiple supermassive black holes (SMBHs) into the nucleus, where they may eventually coalesce. Identifying post-merger-scale (that is, less than around a few kpc) dual SMBHs is a critical pathway to understanding their dynamical evolution and successive mergers(2). Whereas serendipitous discovery of -kpc-scale dual SMBHs at z < 1 is possible(3), such systems are elusive at z > 2 but critical in constraining the progenitors of SMBH mergers. The redshift z approximate to 2 also marks the epoch of peak activity of luminous quasars(4), and therefore the probing of this spatial regime at high redshift is of particular importance in understanding the evolution of quasars. However, given stringent resolution requirements, there is currently no confirmed z > 2 (refs. (5-8)). Here, we report two sub-arcsec double quasars at z > 2 that were discovered from a targeted search with a novel astrometric technique, demonstrating a high success rate (greater than or similar to 50%) in this systematic approach. These high-redshift double quasars could be the long-sought kpc-scale dual SMBHs, or sub-arcsec gravitationally lensed quasar images. One of these double quasars (at z = 2.95) was spatially resolved with optical spectroscopy, and slightly favours the scenario of a physical quasar pair with a projected separation of 3.5 kpc (0.46 ''). Follow-up observations of double quasars discovered by this targeted approach will be able to provide observational constraints on kpc-scale dual SMBHs at z > 2.
  • Victoria Strait, Marusa Bradac, Dan Coe, Brian C. Lemaux, Adam C. Carnall, Larry Bradley, Debora Pelliccia, Keren Sharon, Adi Zitrin, Ana Acebron, Chloe Neufeld, Felipe Andrade-Santos, Roberto J. Avila, Brenda L. Frye, Guillaume Mahler, Mario Nonino, Sara Ogaz, Masamune Oguri, Masami Ouchi, Rachel Paterno-Mahler, Daniel P. Stark, Ramesh Mainali, Pascal A. Oesch, Michele Trenti, Daniela Carrasco, William A. Dawson, Christine Jones, Keiichi Umetsu, Benedetta Vulcani
    ASTROPHYSICAL JOURNAL 910(2) 2021年4月  
    We present constraints on the physical properties (including stellar mass, age, and star formation rate) of 207 6 less than or similar to z less than or similar to 8 galaxy candidates from the Reionization Lensing Cluster Survey (RELICS) and Spitzer-RELICS surveys. We measure photometry using T-PHOT and perform spectral energy distribution fitting using EAzY and BAGPIPES. Of the 207 candidates for which we could successfully measure (or place limits on) Spitzer fluxes, 23 were demoted to likely z < 4. Among the high-z candidates, we find intrinsic stellar masses between 1 x 10(6)MM<sub, and rest-frame UV absolute magnitudes between -22.6 and -14.5 mag. While our sample is mostly comprised of galaxies, it extends to. Our sample spans similar to 4 orders of magnitude in stellar mass and star formation rates, and exhibits ages that range from maximally young to maximally old. We highlight 11 z >= 6.5 galaxies with detections in Spitzer/IRAC imaging, several of which show evidence for some combination of evolved stellar populations, large contributions of nebular emission lines, and/or dust. Among these is PLCKG287+32-2013, one of the brightest z similar to 7 candidates known (AB mag 24.9 at 1.6 mu m) with a Spitzer 3.6 mu m flux excess suggesting strong [O iii] + H-beta emission (similar to 1000 A rest-frame equivalent width). We discuss the possible uses and limits of our sample and present a public catalog of Hubble + Spitzer photometry along with physical property estimates for all objects in the sample. Because of their apparent brightnesses, high redshifts, and variety of stellar populations, these objects are excellent targets for follow-up with the James Webb Space Telescope.
  • V. Ghirardini, E. Bulbul, D. N. Hoang, M. Klein, N. Okabe, V. Biffi, M. Brüggen, M. E. Ramos-Ceja, J. Comparat, M. Oguri, T. W. Shimwell, K. Basu, A. Bonafede, A. Botteon, G. Brunetti, R. Cassano, F. De Gasperin, K. Dennerl, E. Gatuzz, F. Gastaldello, H. Intema, A. Merloni, K. Nandra, F. Pacaud, P. Predehl, T. H. Reiprich, J. Robrade, H. Röttgering, J. Sanders, R. J. Van Weeren, W. L. Williams
    Astronomy and Astrophysics 647 2021年3月1日  
    Aims. We examine the X-ray, optical, and radio properties of the member clusters of a new supercluster discovered during the SRG/eROSITA Performance Verification phase. Methods. We analyzed the 140 deg2 eROSITA Final Equatorial Depth Survey (eFEDS) field observed during the Performance Verification phase to a nominal depth of about 2.3 ks. In this field, we detect a previously unknown supercluster consisting of a chain of eight galaxy clusters at z ~ 0.36. The redshifts of these members were determined through Hyper Suprime-Cam photometric measurements. We examined the X-ray morphological and dynamical properties, gas, and total mass out to R500 of the members and compare these with the same properties of the general population of clusters detected in the eFEDS field. We further investigated the gas in the bridge region between the cluster members for a potential WHIM detection. We also used radio follow-up observations with LOFAR and uGMRT to search for diffuse emission and constrain the dynamic state of the system. Results. We do not find significant differences between the morphological parameters and properties of the intra-cluster medium of the clusters embedded in this large-scale filament and those of the eFEDS clusters. We also provide upper limits on the electron number density and mass of the warm-hot intergalactic medium as provided by the eROSITA data. These limits are consistent with previously reported values for the detections in the vicinity of clusters of galaxies. In LOFAR and uGMRT follow-up observations of the northern part of this supercluster, we find two new radio relics and a radio halo that are the result of major merger activity in the system. Conclusions. These early results show the potential of eROSITA to probe large-scale structures such as superclusters and the properties of their members. Our forecasts show that we will be able to detect about 450 superclusters, with approximately 3000 member clusters located in the eROSITADE region at the final eROSITA all-sky survey depth, enabling statistical studies of the properties of superclusters and their constituents embedded in the cosmic web.
  • M. Hilton, C. Sifón, S. Naess, M. Madhavacheril, M. Oguri, E. Rozo, E. Rykoff, S. Adhikari, M. Aguena, S. Aiola, S. Allam, S. Amodeo, A. Amon, J. Annis, B. Ansarinejad, T. M.C. Abbott, C. Aros-Bunster, J. E. Austermann, S. Avila, D. Bacon, N. Battaglia, J. A. Beall, D. T. Becker, G. M. Bernstein, E. Bertin, T. Bhandarkar, S. Bhargava, J. R. Bond, D. Brooks, D. L. Burke, E. Calabrese, M. Carrasco Kind, J. Carretero, S. K. Choi, A. Choi, C. Conselice, L. N. Da Costa, M. Costanzi, D. Crichton, K. T. Crowley, R. Dünner, E. V. Denison, M. J. Devlin, S. R. Dicker, H. T. Diehl, J. P. Dietrich, P. Doel, S. M. Duff, A. J. Duivenvoorden, J. Dunkley, S. Everett, S. Ferraro, A. Ferté, B. Flaugher, J. Frieman, I. Ferrero, P. A. Gallardo, J. García-Bellido, E. Gaztanaga, P. Giles, J. E. Golec, M. B. Gralla, S. Grandis, D. Gruen, D. W. Gerdes, R. A. Gruendl, J. Gschwend, G. Gutierrez, D. Han, W. G. Hartley, M. Hasselfield, J. C. Hill, G. C. Hilton, A. D. Hincks, S. R. Hinton, S. P.P. Ho, K. Honscheid, B. Hoyle, J. Hubmayr, K. M. Huffenberger, J. P. Hughes, A. T. Jaelani, B. Jain, D. J. James, T. Jeltema, S. Kent, K. Knowles, B. J. Koopman, K. Kuehn, O. Lahav, M. Lima, Y. T. Lin, M. Lokken, S. I. Loubser, N. MacCrann, M. A.G. Maia, T. A. Marriage, J. Martin, J. McMahon, P. Melchior
    Astrophysical Journal, Supplement Series 253(1) 2021年3月  
    We present a catalog of 4195 optically confirmed Sunyaev–Zel’dovich (SZ) selected galaxy clusters detected with signal-to-noise ratio >4 in 13,211 deg2 of sky surveyed by the Atacama Cosmology Telescope (ACT). Cluster candidates were selected by applying a multifrequency matched filter to 98 and 150 GHz maps constructed from ACT observations obtained from 2008 to 2018 and confirmed using deep, wide-area optical surveys. The clusters span the redshift range 0.04 < z < 1.91 (median z = 0.52). The catalog contains 222 z > 1 clusters, and a total of 868 systems are new discoveries. Assuming an SZ signal versus mass-scaling relation calibrated from X-ray observations, the sample has a 90% completeness mass limit of M500c > 3.8 × 1014 Me, evaluated at z = 0.5, for clusters detected at signal-to-noise ratio >5 in maps filtered at an angular scale of 2 4. The survey has a large overlap with deep optical weak-lensing surveys that are being used to calibrate the SZ signal mass-scaling relation, such as the Dark Energy Survey (4566 deg2), the Hyper Suprime-Cam Subaru Strategic Program (469 deg2), and the Kilo Degree Survey (825 deg2). We highlight some noteworthy objects in the sample, including potentially projected systems, clusters with strong lensing features, clusters with active central galaxies or star formation, and systems of multiple clusters that may be physically associated. The cluster catalog will be a useful resource for future cosmological analyses and studying the evolution of the intracluster medium and galaxies in massive clusters over the past 10 Gyr.
  • J. D.R. Pierel, S. Rodney, G. Vernardos, M. Oguri, R. Kessler, T. Anguita
    Astrophysical Journal 908(2) 2021年2月20日  
    One of the primary mission objectives of the Roman Space Telescope is to investigate the nature of dark energy with a variety of methods. Observations of Type I supernovae (SNe Ia) will be one of the principal anchors of the Roman cosmology program through traditional luminosity distance measurements. This SNe Ia cosmology program can provide another valuable cosmological probe, without altering the strategy of the mission: time delay cosmography with gravitationally lensed supernova (SN). In this work, we forecast lensed SN cosmology constraints with the Roman Space Telescope, while providing useful tools for future work. Using the anticipated characteristics of the Roman SNe Ia survey, we have constructed mock catalogs of expected resolved lensing systems, as well as strongly lensed Type Ia and core-collapse (CC) SN light curves, including microlensing effects. We predict Roman will find ∼11 lensed SNe Ia and ∼20 CCSNe, depending on the survey strategy. Next, we estimate the time delay precision obtainable with Roman (Ia: ∼2 days, CC: ∼3 days), and use a Fisher matrix analysis to derive projected constraints on H 0,Ω m , and the dark energy equation of state, w, for each SNe Ia survey strategy. A strategy optimized for the discovery of high-redshift SNe Ia is preferred when considering the constraints possible from both SNe Ia and lensed SN cosmology, also delivering ∼1.5 times more lensed SNe than other proposed survey strategies.
  • A. J. Shajib, S. Birrer, T. Treu, M. W. Auger, A. Agnello, T. Anguita, E. J. Buckley-Geer, J. H.H. Chan, T. E. Collett, F. Courbin, C. D. Fassnacht, J. Frieman, I. Kayo, C. Lemon, H. Lin, P. J. Marshall, R. McMahon, A. More, N. D. Morgan, V. Motta, M. Oguri, F. Ostrovski, C. E. Rusu, P. L. Schechter, T. Shanks, S. H. Suyu, G. Meylan, T. M.C. Abbott, S. Allam, J. Annis, S. Avila, E. Bertin, D. Brooks, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, C. E. Cunha, L. N. Da Costa, J. De Vicente, S. Desai, P. Doel, B. Flaugher, P. Fosalba, J. García-Bellido, D. W. Gerdes, D. Gruen, R. A. Gruendl, G. Gutierrez, W. G. Hartley, D. L. Hollowood, B. Hoyle, D. J. James, K. Kuehn, N. Kuropatkin, O. Lahav, M. Lima, M. A.G. Maia, M. March, J. L. Marshall, P. Melchior, F. Menanteau, R. Miquel, A. A. Plazas, E. Sanchez, V. Scarpine, I. Sevilla-Noarbe, M. Smith, M. Soares-Santos, F. Sobreira, E. Suchyta, M. E.C. Swanson, G. Tarle, A. R. Walker
    Monthly Notices of the Royal Astronomical Society 501(2) 2833-2835 2021年2月1日  
    The paper 'Is every strong lens model unhappy in its own way? Uniform modelling of a sample of 13 quadruply+ imaged quasars' was published inMNRAS, 483, 4, 5649-5671 (2019). The coordinate values of the image positions in table 4 were wrongly printed due to a clerical error. At a later stage of writing the manuscript, we have changed the zero-point definition of the lens coordinate systems, but the relative image positions were not accounted for this change of definition while printing out table 4. We provide the updated Table 4 below. This error does not impact any other results of the paper in any way, except for the table itself. We thank Collin Werner and Paul Schechter for helping us identify this error.
  • Nobuhiro Okabe, Simon Dicker, Dominique Eckert, Tony Mroczkowski, Fabio Gastaldello, Yen-Ting Lin, Mark Devlin, Charles E. Romero, Mark Birkinshaw, Craig Sarazin, Cathy Horellou, Tetsu Kitayama, Keiichi Umetsu, Mauro Sereno, Brian S. Mason, John A. ZuHone, Ayaka Honda, Hiroki Akamatsu, I-Non Chiu, Kotaro Kohno, Kai-Yang Lin, Elinor Medezinski, Satoshi Miyazaki, Ikuyuki Mitsuishi, Atsushi J. Nishizawa, Masamune Oguri, Naomi Ota, Florian Pacaud, Marguerite Pierre, Jonathan Sievers, Vernesa Smolcic, Sara Stanchfield, Keigo Tanaka, Ryoichi Yamamoto, Chong Yang, Atsushi Yoshida
    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 501(2) 1701-1732 2021年2月  
    We present results from simultaneous modelling of high angular resolution GBT/MUSTANG-2 90 GHz Sunyaev-Zel'dovich effect (SZE) measurements and XMM-XXL X-ray images of three rich galaxy clusters selected from the HSC-SSP Survey. The combination of high angular resolution SZE and X-ray imaging enables a spatially resolved multicomponent analysis, which is crucial to understand complex distributions of cluster gas properties. The targeted clusters have similar optical richnesses and redshifts, but exhibit different dynamical states in their member galaxy distributions: a single-peaked cluster, a double-peaked cluster, and a cluster belonging to a supercluster. A large-scale residual pattern in both regular Compton-parameter y and X-ray surface brightness distributions is found in the single-peaked cluster, indicating a sloshing mode. The double-peaked cluster shows an X-ray remnant cool core between two SZE peaks associated with galaxy concentrations. The temperatures of the two peaks reach similar to 20-30 keV in contrast to the cool core component of similar to 2 keV, indicating a violent merger. The main SZE signal for the supercluster is elongated along a direction perpendicular to the major axis of the X-ray core, suggesting a minor merger before core passage. The S-X and y distributions are thus perturbed at some level, regardless of the optical properties. We find that the integrated Compton y parameter and the temperature for the major merger are boosted from those expected by the weak-lensing mass and those for the other two clusters show no significant deviations, which is consistent with predictions of numerical simulations.
  • Anton T Jaelani, Cristian E Rusu, Issha Kayo, Anupreeta More, Alessandro Sonnenfeld, John D Silverman, Malte Schramm, Timo Anguita, Naohisa Inada, Daichi Kondo, Paul L Schechter, Khee-Gan Lee, Masamune Oguri, James H H Chan, Kenneth C Wong, Kaiki T Inoue
    Monthly Notices of the Royal Astronomical Society 502(1) 1487-1493 2021年1月20日  
    <title>Abstract</title> We present spectroscopic confirmation of three new two-image gravitationally lensed quasars, compiled from existing strong lens and X-ray catalogs. Images of HSC J091843.27–022007.5 show a red galaxy with two blue point sources at either side, separated by 2.26 arcsec. This system has a source and a lens redshifts zs = 0.804 and zℓ = 0.459, respectively, as obtained by our follow-up spectroscopic data. CXCO J100201.50+020330.0 shows two point sources separated by 0.85 arcsec on either side of an early-type galaxy. The follow-up spectroscopic data confirm the fainter quasar has the same redshift with the brighter quasar from the SDSS fiber spectrum at zs = 2.016. The deflecting foreground galaxy is a typical early-type galaxy at a redshift of zℓ = 0.439. SDSS J135944.21+012809.8 has two point sources with quasar spectra at the same redshift zs = 1.096, separated by 1.05 arcsec, and fits to the HSC images confirm the presence of a galaxy between these. These discoveries demonstrate the power of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP)’s deep imaging and wide sky coverage. Combined with existing X-ray source catalogues and follow-up spectroscopy, the HSC-SSP provides us unique opportunities to find multiple-image quasars lensed by a foreground galaxy.
  • Xiangchong Li, Masamune Oguri, Nobuhiko Katayama, Wentao Luo, Wenting Wang, Jiaxin Han, Hironao Miyatake, Keigo Nakamura, Surhud More
    ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES 251(2) 2020年12月  
    We apply the Fourier Power Function Shapelets (FPFS) shear estimator to the first-year data of the Hyper Suprime-Cam survey to construct a shape catalog. The FPFS shear estimator has been demonstrated to have a multiplicative bias less than 1% in the absence of blending, regardless of complexities of galaxy shapes, smears of point spread functions (PSFs), and contamination from noise. The blending bias is calibrated with realistic image simulations, which include the impact of neighboring objects, using the COSMOS Hubble Space Telescope images. Here we carefully test the influence of PSF model residual on the FPFS shear estimation and the uncertainties in the shear calibration. Internal null tests are conducted to characterize potential systematics in the FPFS shape catalog, and the results are compared with those measured using a catalog where the shapes were estimated using the re-Gaussianization algorithms. Furthermore, we compare various weak-lensing measurements between the FPFS shape catalog and the re-Gaussianization shape catalog and conclude that the weak-lensing measurements between these two shape catalogs are consistent with each other within the statistical uncertainty.
  • I-Non Chiu, Teppei Okumura, Masamune Oguri, Aniket Agrawal, Keiichi Umetsu, Yen-Ting Lin
    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 498(2) 2030-2053 2020年10月  
    We perform a self-calibration of the richness-to-mass (N-M) relation of CAMIRA galaxy clusters with richness N >= 15 at redshift 0.2 <= z < 1.1 by modelling redshift-space two-point correlation functions. These correlation functions are the autocorrelation function xi(cc) of CAMIRA clusters, the autocorrelation function xi(gg) of the CMASS galaxies spectroscopically observed in the Baryon Oscillation Spectroscopic Survey, and the cross-correlation function xi(cg) between these two samples. We focus on constraining the normalization A(N) of the N-M relation with a forward-modelling approach, carefully accounting for the redshift-space distortion, the Finger-of-God effect, and the uncertainty in photometric redshifts of CAMIRA clusters. The modelling also takes into account the projection effect on the halo bias of CAMIRA clusters. The parameter constraints are shown to be unbiased according to validation tests using a large set of mock catalogues constructed from N-body simulations. At the pivotal mass M-500 = 10(14) h(-1) M-circle dot and the pivotal redshift z(piv) = 0.6, the resulting normalization A(N) is constrained as 13.8(-4.2)(+5.8), 13.2(-2.7)(+3.4), and 11.9(-1.9)(+3.0) by modelling xi(cc), xi(cc) + xi(cg), and xi(cc) + xi(cg) +(.) xi(gg), with average uncertainties at levels of 36, 23, and 21 per cent, respectively. We find that the resulting A(N) is statistically consistent with those independently obtained from weak-lensing magnification and from a joint analysis of shear and cluster abundance, with a preference for a lower value at a level of less than or similar to 1.9 sigma. This implies that the absolute mass scale of CAMIRA clusters inferred from clustering is mildly higher than those from the independent methods. We discuss the impact of the selection bias introduced by the cluster finding algorithm, which is suggested to be a subdominant factor in this work.

主要なMISC

 21

主要な書籍等出版物

 2
  • 大栗, 真宗
    朝倉書店 2025年3月 (ISBN: 9784254135336)

主要な担当経験のある科目(授業)

 11

主要な共同研究・競争的資金等の研究課題

 16