研究者業績
基本情報
- 所属
- 千葉大学 先進科学センター 助教(兼任)大学院理学研究院 物理学研究部門 助教
- 学位
- 博士（理学）(2019年3月 東京大学)修士（理学）(2016年3月 東京大学)
- 研究者番号
- 00914277
- ORCID ID
https://orcid.org/0000-0002-7934-2569- J-GLOBAL ID
- 202101012137702608
- researchmap会員ID
- R000025251
主要な研究分野
2経歴
5-
2023年4月 - 現在
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2022年6月 - 2023年3月
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2021年4月 - 2022年6月
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2019年4月 - 2021年3月
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2016年4月 - 2019年3月
学歴
2-
2014年4月 - 2019年3月
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2010年4月 - 2014年3月
受賞
1-
2016年3月
論文
57-
Phys.Rev.D 110(10) 103548-103548 2024年11月15日
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Monthly Notices of the Royal Astronomical Society 528(3) 4513-4527 2024年1月10日ABSTRACT We present cosmological constraints derived from peak counts, minimum counts, and the angular power spectrum of the Subaru Hyper Suprime-Cam first-year (HSC Y1) weak lensing shear catalogue. Weak lensing peak and minimum counts contain non-Gaussian information and hence are complementary to the conventional two-point statistics in constraining cosmology. In this work, we forward-model the three summary statistics and their dependence on cosmology, using a suite of N-body simulations tailored to the HSC Y1 data. We investigate systematic and astrophysical effects including intrinsic alignments, baryon feedback, multiplicative bias, and photometric redshift uncertainties. We mitigate the impact of these systematics by applying cuts on angular scales, smoothing scales, signal-to-noise ratio bins, and tomographic redshift bins. By combining peaks, minima, and the power spectrum, assuming a flat-ΛCDM model, we obtain $S_{8} \equiv \sigma _8\sqrt{\Omega _m/0.3}= 0.810^{+0.022}_{-0.026}$, a 35 per cent tighter constraint than that obtained from the angular power spectrum alone. Our results are in agreement with other studies using HSC weak lensing shear data, as well as with Planck 2018 cosmology and recent CMB lensing constraints from the Atacama Cosmology Telescope and the South Pole Telescope.
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Monthly Notices of the Royal Astronomical Society 527(3) 5974-5987 2024年1月1日We perform the weak lensing mass mapping analysis to identify troughs, which are defined as local minima in the mass map. Since weak lensing probes the projected matter distribution along the line of sight, these troughs can be produced by single or multiple voids projected along the line of sight. To scrutinize the origins of the weak lensing troughs, we systematically investigate the line-of-sight structure of troughs selected from the latest Subaru Hyper Suprime-Cam (HSC) Year 3 weak lensing data covering 433.48 deg2. From a curved sky mass map constructed with the HSC data, we identify 15 troughs with the signal-to-noise ratio higher than 5.7 and address their line-of-sight density structure utilizing redshift distributions of two galaxy samples, photometric luminous red galaxies observed by HSC and spectroscopic galaxies detected by Baryon Oscillation Spectroscopic Survey. While most weak lensing signals due to the troughs are explained by multiple voids aligned along the line of sight, we find that two of the 15 troughs potentially originate from single voids at redshift ∼0.3. The single void interpretation appears to be consistent with our three-dimensional mass mapping analysis. We argue that single voids can indeed reproduce observed weak lensing signals at the troughs if these voids are not spherical but are highly elongated along the line-of-sight direction.
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Phys.Rev.D 108(12) 123541-123541 2023年12月15日
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Physical Review D 108(12) 2023年12月15日We present cosmology results from a blinded joint analysis of cosmic shear, ζ±, galaxy-galaxy weak lensing, Δς(R), and projected galaxy clustering, wp(R), measured from the Hyper Suprime-Cam three-year (HSC-Y3) shape catalog and the Sloan Digital Sky Survey (SDSS) DR11 spectroscopic galaxy catalog - a 3×2 pt cosmology analysis. We define luminosity-cut, and therefore nearly volume-limited, samples of SDSS galaxies to serve as the tracers of wp and as the lens samples for Δς in three spectroscopic redshift bins spanning the range 0.15<z<0.7. For the ζ± and Δς measurements, we use a single sample of about seven million source galaxies over 416 deg2, selected from HSC-Y3 based on having photometric redshifts (photo-z) greater than 0.75. The deep, high-quality HSC-Y3 data enable significant detections of the Δς signals, with integrated signal-to-noise ratio S/N∼24 in the range 3≤R/[h-1 Mpc]≤30 over the three lens samples. ζ± has S/N∼19 in the range 8′≤ ≤50′ and 30′≤ ≤150′ for ζ+ and ζ-, respectively. For cosmological parameter inference, we use the dark emulator package, combined with a halo occupation distribution prescription for the relation between galaxies and halos, to model wp and Δς down to quasinonlinear scales, and we estimate cosmological parameters after marginalizing over nuisance parameters. In our baseline analysis we employ an uninformative flat prior of the residual photo-z error, given by Π(Δzph)=U(-1,1), to model a residual bias in the mean redshift of HSC source galaxies. Comparing the relative lensing amplitudes for Δς in the three redshift bins and for ζ± with the single HSC source galaxy sample allows us to calibrate the photo-z parameter Δzph to the precision of σ(Δzph)≃0.09. With these methods, we obtain a robust constraint on the cosmological parameters for the flat ΛCDM model: S8=σ8(ωm/0.3)0.5=0.763-0.036+0.040, or the best-constrained parameter given by S8′=σ8(ωm/0.3)0.22=0.721±0.028, determined with about 4% fractional precision. Based on multidimensional tension metrics, HSC-Y3 data exhibits about 2.5σ tension with the cosmological constraint inferred by Planck for the ΛCDM model, and hints at a nonzero residual photo-z bias implying that the true mean redshift of the HSC galaxies at z≳0.75 is higher than that implied by the original photo-z estimates.
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Physical Review D 108(12) 2023年12月15日We measure weak lensing cosmic shear power spectra from the 3-year galaxy shear catalog of the Hyper Suprime-Cam (HSC) Subaru Strategic Program imaging survey. The shear catalog covers 416 deg2 of the northern sky, with a mean i-band seeing of 0.59 arcsec and an effective galaxy number density of 15 arcmin-2 within our adopted redshift range. With an i-band magnitude limit of 24.5 mag, and four tomographic redshift bins spanning 0.3≤zph≤1.5 based on photometric redshifts, we obtain a high-significance measurement of the cosmic shear power spectra, with a signal-to-noise ratio of approximately 26.4 in the multipole range 300<ℓ<1800. The accuracy of our power spectrum measurement is tested against realistic mock shear catalogs, and we use these catalogs to get a reliable measurement of the covariance of the power spectrum measurements. We use a robust blinding procedure to avoid confirmation bias, and model various uncertainties and sources of bias in our analysis, including point spread function systematics, redshift distribution uncertainties, the intrinsic alignment of galaxies and the modeling of the matter power spectrum. For a flat ΛCDM model, we find S8σ8(ωm/0.3)0.5=0.776-0.033+0.032, which is in excellent agreement with the constraints from the other HSC Year 3 cosmology analyses, as well as those from a number of other cosmic shear experiments. This result implies a ∼2σ-level tension with the Planck 2018 cosmology. We study the effect that various systematic errors and modeling choices could have on this value, and find that they can shift the best-fit value of S8 by no more than ∼0.5σ, indicating that our result is robust to such systematics.
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Physical Review D 108(12) 2023年12月15日We perform a blinded cosmology analysis with cosmic shear two-point correlation functions measured from more than 25 million galaxies in the Hyper Suprime-Cam three-year shear catalog in four tomographic redshift bins ranging from 0.3 to 1.5. After conservative masking and galaxy selection, the survey covers 416 deg2 of the northern sky with an effective galaxy number density of 15 arcmin-2 over the four redshift bins. The 2PCFs adopted for cosmology analysis are measured in the angular range; 7.1<θ/arcmin<56.6 for ζ+ and 31.2<θ/arcmin<248 for ζ-, with a total signal-to-noise ratio of 26.6. We apply a conservative, wide, flat prior on the photometric redshift errors on the last two tomographic bins, and the relative magnitudes of the cosmic shear amplitude across four redshift bins allow us to calibrate the photometric redshift errors. With this flat prior on redshift errors, we find ωm=0.256-0.044+0.056 and S8σ8ωm/0.3=0.769-0.034+0.031 (both 68% C.I.) for a flat Λ cold dark matter cosmology. We find, after unblinding, that our constraint on S8 is consistent with the Fourier space cosmic shear and the 3×2 pt analyses on the same HSC dataset. We carefully study the potential systematics from astrophysical and systematic model uncertainties in our fiducial analysis using synthetic data, and report no biases (including projection bias in the posterior space) greater than 0.5σ in the estimation of S8. Our analysis hints that the mean redshifts of the two highest tomographic bins are higher than initially estimated. In addition, a number of consistency tests are conducted to assess the robustness of our analysis. Comparing our result with Planck-2018 cosmic microwave background observations, we find a ∼2σ tension for the ΛCDM model.
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Physical Review D 108(12) 2023年12月15日We present cosmological parameter constraints from a blind joint analysis of three two-point correlation functions measured from the Year 3 Hyper Suprime-Cam (HSC-Y3) imaging data, covering about 416 deg2, and the SDSS DR11 spectroscopic galaxies spanning the redshift range [0.15, 0.70]. We subdivide the SDSS galaxies into three luminosity-cut, and therefore nearly volume-limited samples separated in redshift, each of which acts as a large-scale structure tracer characterized by the measurement of the projected correlation function, wp(R). We also use the measurements of the galaxy-galaxy weak-lensing signal Δς(R) for each of these SDSS samples which act as lenses for a secure sample of source galaxies selected from the HSC-Y3 shape catalog based on their photometric redshifts. We combine these measurements with the cosmic shear correlation functions, ζ± measured for our HSC source sample. We model these observables with the minimal bias model of the galaxy clustering observables in the context of a flat ΛCDM cosmology. We use conservative scale cuts, R>12 and 8h-1 Mpc for Δς and wp, respectively, where the minimal bias model is valid, in addition to conservative prior on the residual bias in the mean redshift of the HSC photometric source galaxies. We present various validation tests of our model as well as analysis methods. Our baseline analysis yields S8=0.775-0.038+0.043 (68% C.I.) for the ΛCDM model, after marginalizing over uncertainties in other parameters. Our value of S8 is consistent with that from the Planck 2018 data, but the credible interval of our result is still relatively large. We show that various internal consistency tests based on different splits of the data are passed. Our results are statistically consistent with those of a companion paper, which extends this analysis to smaller scales with an emulator-based halo model, using Δς(R) and wp(R) down to R>3 and 2h-1 Mpc, respectively.
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Physical Review D 108(12) 2023年12月15日We utilize the Sloan Digital Sky Survey Baryon Oscillation Spectroscopic Survey (SDSS-BOSS) galaxies and its overlap with approximately 416 sq degrees of deep grizy-band imaging from the Subaru Hyper Suprime-Cam Survey (HSC). We perform measurements of three two-point correlations which form the basis of the cosmological inference presented in our companion papers, Miyatake et al. and Sugiyama et al. We use three approximately volume limited subsamples of spectroscopic galaxies by their i-band magnitude from the SDSS-BOSS: LOWZ (0.1<z<0.35), CMASS1 (0.43<z<0.55) and CMASS2 (0.55<z<0.7), respectively. We present high signal-to-noise ratio measurements of the projected correlation functions of these galaxies, which is expected to be proportional to the projected matter correlation function on large scales with a proportionality constant dependent on the bias of galaxies. In order to help break the degeneracy between the amplitude of the matter correlation and the bias of these spectroscopic galaxies, we use the distortions of the shapes of fainter galaxies in HSC due to weak gravitational lensing, to measure the galaxy-galaxy lensing signal, which probes the projected galaxy-matter cross-correlation function of the SDSS-BOSS galaxies. We also measure the cosmic shear correlation functions from HSC galaxies which is related to the projected matter correlation function. We demonstrate the robustness of our measurements by subjecting each of them to a variety of systematic tests. Our use of a single sample of HSC source galaxies is crucial to calibrate any residual systematic biases in the inferred redshifts of our galaxies. We also describe the construction of a suite of mocks: (i) spectroscopic galaxy catalogs which obey the clustering and abundance of each of the three SDSS-BOSS subsamples, and (ii) galaxy shape catalogs which obey the footprint of the HSC survey and have been appropriately sheared by the large-scale structure expected in a Λ Cold Dark Matter model. We use these mock catalogs to compute the covariance of each of our observables.
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Astronomy & Astrophysics 672 A51-A51 2023年3月27日Context. Weak lensing mass-mapping is a useful tool for accessing the full distribution of dark matter on the sky, but because of intrinsic galaxy ellipticies, finite fields, and missing data, the recovery of dark matter maps constitutes a challenging, ill-posed inverse problem Aims. We introduce a novel methodology that enables the efficient sampling of the high-dimensional Bayesian posterior of the weak lensing mass-mapping problem, relying on simulations to define a fully non-Gaussian prior. We aim to demonstrate the accuracy of the method to simulated fields, and then proceed to apply it to the mass reconstruction of the HST/ACS COSMOS field. Methods. The proposed methodology combines elements of Bayesian statistics, analytic theory, and a recent class of deep generative models based on neural score matching. This approach allows us to make full use of analytic cosmological theory to constrain the 2pt statistics of the solution, to understand any differences between this analytic prior and full simulations from cosmological simulations, and to obtain samples from the full Bayesian posterior of the problem for robust uncertainty quantification. Results. We demonstrate the method in the κTNG simulations and find that the posterior mean significantly outperfoms previous methods (Kaiser–Squires, Wiener filter, Sparsity priors) both for the root-mean-square error and in terms of the Pearson correlation. We further illustrate the interpretability of the recovered posterior by establishing a close correlation between posterior convergence values and the S/N of the clusters artificially introduced into a field. Finally, we apply the method to the reconstruction of the HST/ACS COSMOS field, which yields the highest-quality convergence map of this field to date. Conclusions. We find the proposed approach to be superior to previous algorithms, scalable, providing uncertainties, and using a fully non-Gaussian prior.
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Monthly Notices of the Royal Astronomical Society 519(2) 2069-2082 2022年12月16日ABSTRACT We present a fast methodology to produce mock observations of the thermal and kinetic Sunyaev–Zel’dovich (SZ) effects based on the dark matter only N-body simulations coupled with the analytic intracluster medium model. The methods employ two different approaches: halo-based pasting (HP) and particle-based pasting (PP). The former pastes gas density and pressure on to haloes and requires only a halo catalogue, and the latter considers the contribution from field particles as well, i.e. particles that do not belong to any haloes and thus utilize the full particle information. Therefore, the PP algorithm incorporates secondary effects beyond the HP algorithm: asphericity of haloes and contribution from diffuse gas. In particular, such a diffuse component is the dominant source of the kinetic SZ effect. As validation of our methods, we have produced 108 all-sky maps with HP and 108 flat-sky maps, which cover $5 \times 5 \, \mathrm{deg}^2$ with both HP and PP, and measured power spectra of the maps. Our method can produce a mock map within a few hours, even for all-sky coverage with a parallel computational environment. The power spectra of HP maps are consistent with the halo model prediction of the thermal SZ effect. On the other hand, the power spectra of PP maps are suppressed due to the halo asphericity but can reproduce better the theoretical prediction for the kinetic SZ effect. We discuss the utility of baryon-pasted mock SZ maps for estimating the covariance matrix of SZ statistics and modelling the selection and projection effects for cluster cosmology.
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Monthly Notices of the Royal Astronomical Society 519(2) 1771-1791 2022年12月9日ABSTRACT Upcoming spectroscopic redshift surveys use emission line galaxies (ELGs) to trace the three-dimensional matter distributions with wider area coverage in the deeper Universe. Since the halos hosting ELGs are young and undergo infall towards more massive halos along filamentary structures, contrary to a widely employed luminous red galaxy sample, the dynamics specific to ELGs should be taken into account to refine the theoretical modelling at non-linear scales. In this paper, we scrutinize the halo occupation distribution (HOD) and clustering properties of ELGs by utilizing IllustrisTNG galaxy formation hydrodynamical simulations. Leveraging stellar population synthesis technique coupled with the photo-ionization model, we compute line intensities of simulated galaxies and construct mock H α and [O ii] ELG catalogues. The line luminosity functions and the relation between the star formation rate and line intensity are well consistent with observational estimates. Next, we measure the HOD and demonstrate that there is a distinct population for the central HOD, which corresponds to low-mass infalling halos. We then perform the statistical inference of HOD parameters from the projected correlation function. Our analysis indicates that the inferred HODs significantly deviate from the HOD measured directly from simulations although the best-fitting model yields a good fit to the projected correlation function. It implies that the information content of the projected correlation function is not adequate to constrain HOD models correctly and thus, it is important to employ mock ELG catalogues to calibrate the functional form of HOD models and add prior information on HOD parameters to robustly determine the HOD.
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Monthly Notices of the Royal Astronomical Society 519(1) 573-584 2022年12月8日ABSTRACT Next-generation weak lensing (WL) surveys, such as by the Vera Rubin Observatory, the Roman Space Telescope, and the Euclid space mission, will supply vast amounts of data probing small, highly non-linear scales. Extracting information from these scales requires higher-order statistics and the controlling of related systematics such as baryonic effects. To account for baryonic effects in cosmological analyses at reduced computational cost, semi-analytic baryonic correction models (BCMs) have been proposed. Here, we study the accuracy of a particular BCM (the A20-BCM) for WL peak counts, a well-studied, simple, and effective higher-order statistic. We compare WL peak counts generated from the full hydrodynamical simulation IllustrisTNG and a baryon-corrected version of the corresponding dark matter-only simulation IllustrisTNG-Dark. We apply galaxy shape noise matching depths reached by DES, KiDS, HSC, LSST, Roman, and Euclid. We find that peak counts from the A20-BCM are (i) accurate at per cent level for peaks with S/N &lt; 4, (ii) statistically indistinguishable from IllustrisTNG in most current and ongoing surveys, but (iii) insufficient for deep future surveys covering the largest solid angles, such as LSST and Euclid. We find that the BCM matches individual peaks accurately, but underpredicts the amplitude of the highest peaks. We conclude that the A20-BCM is a viable substitute for full hydrodynamical simulations in cosmological parameter estimation from beyond-Gaussian statistics for ongoing and future surveys with modest solid angles. For the largest surveys, the A20-BCM must be refined to provide a more accurate match, especially to the highest peaks.
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Journal of Low Temperature Physics 209(5-6) 971-979 2022年12月
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Physical Review D 106(8) 2022年10月21日We present validation tests of emulator-based halo model method for cosmological parameter inference, assuming hypothetical measurements of the projected correlation function of galaxies, $w_{\rm p}(R)$, and the galaxy-galaxy weak lensing, $\Delta\!\Sigma(R)$, from the spectroscopic SDSS galaxies and the Hyper Suprime-Cam Year1 (HSC-Y1) galaxies. To do this, we use \textsc{Dark Emulator} developed in Nishimichi et al. based on an ensemble of $N$-body simulations, which is an emulation package enabling a fast, accurate computation of halo clustering quantities for flat-geometry $w$CDM cosmologies. Adopting the halo occupation distribution, the emulator allows us to obtain model predictions of $\Delta\!\Sigma$ and $w_{\rm p}$ for the SDSS-like galaxies at a few CPU seconds for an input set of parameters. We present performance and validation of the method by carrying out Markov Chain Monte Carlo analyses of the mock signals measured from a variety of mock catalogs that mimic the SDSS and HSC-Y1 galaxies. We show that the halo model method can recover the underlying true cosmological parameters to within the 68\% credible interval, except for the mocks including the assembly bias effect (although we consider the unrealistically-large amplitude of assembly bias effect). Even for the assembly bias mock, we demonstrate that the cosmological parameters can be recovered {\it if} the analysis is restricted to scales $R\gtrsim 10~h^{-1}{\rm Mpc}$. We also show that, by using a single population of source galaxies to infer the relative strengths of $\Delta\!\Sigma$ for multiple lens samples at different redshifts, the joint probes method allows for self-calibration of photometric redshift errors and multiplicative shear bias. Thus we conclude that the emulator-based halo model method can be safely applied to the HSC-Y1 dataset, achieving a precision of $\sigma(S_8)\simeq 0.04$....
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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.
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Space Telescopes and Instrumentation 2022: Ultraviolet to Gamma Ray 12181 2022年8月31日
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Physical Review D 107(10) 103534 2022年8月 査読有りWe present a novel $n$EPT ($n$th-order Eulerian Perturbation Theory) scheme to model the nonlinear density field by the summation up to $n$th-order density fields in perturbation theory. The obtained analytical power spectrum shows excellent agreement with the results from all 20 Dark-Quest suites of $N$-body simulations spreading over a broad range of cosmologies. The agreement is much better than the conventional two-loop Standard Perturbation Theory and would reach out to $k_{\rm max}\simeq 0.4~h/{\rm Mpc}$ at $z=3$ for the best-fitting Planck cosmology, without any free parameters. The method can accelerate the forward modeling of the non-linear cosmological density field, an indispensable probe of cosmic mysteries such as inflation, dark energy, and dark matter.
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Physical Review D 105(12) 2022年6月We present cosmological parameter constraints from a blinded joint analysis of galaxy-galaxy weak lensing, Δ Σ (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 Δ Σ 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 Δ Σ 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 Λ CDM cosmological model. We compare the model predictions with the measurements in each redshift bin on large scales, R >12 and 8 h-1 Mpc for Δ Σ (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 Δ Σ measurements. When we employ weak priors on cosmological parameters, without cosmic microwave background (CMB) information, we find S8=0.93 6-0.086+0.092, σ8=0.8 5-0.11+0.16, and Ωm=0.28 3-0.035+0.12 (mode and 68% credible interval) for the flat Λ CDM 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=0.81 7-0.021+0.022, σ8=0.89 2-0.056+0.051, Ωm=0.24 6-0.035+0.045, and the equation-of-state parameter of dark energy, wde=-1.2 8-0.19+0.20 for the flat w CDM model, which is consistent with the flat Λ CDM model to within the error bars....
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Monthly Notices of the Royal Astronomical Society 512(2) 1730-1750 2022年5月For future surveys of fast radio bursts (FRBs), we clarify information available from cosmic dispersion measures (DMs) through cross-correlation analyses of foreground dark matter haloes (hosting galaxies and galaxy clusters) with their known redshifts. With a halo-model approach, we predict that the cross-correlation with cluster-sized haloes is less affected by the details of gastrophysics, providing robust cosmological information. For less massive haloes, the cross-correlation at angular scales of ${\lt} 10\, \mathrm{arcmin}$ is sensitive to gas expelled from the halo centre due to galactic feedback. Assuming 20 000 FRBs over $20\,000 \, {\rm deg}^2$ with a localization error being 3 arcmin, we expect that the cross-correlation signal at halo masses of 1012-$10^{14}\, {\rm M}_\odot$ can be measured with a level of ${\sim} 1{ { \ \rm per\ cent } }$ precision in a redshift range of 0 < z < 1. Such precise measurements enable one to put a 1.5 per cent level constraint on $\sigma _8\, (\Omega _\mathrm{M}/0.3)^{0.5}$ and a 3 per cent level constraint on (Ωb/0.049)(h/0.67)(fe/0.95) (σ8, ΩM, Ωb, h, and fe are the linear mass variance smoothed at $8\, h^{-1}\mathrm{\,Mpc}$, mean mass density, mean baryon density, the present-day Hubble parameter, and fraction of free electrons in cosmic baryons today, respectively), whereas the gas-to-halo mass relation in galaxies and clusters can be constrained with a level of $10$-$20{ { \ \rm per\ cent } }$. Furthermore the cross-correlation analyses can break the degeneracy among Ωb, h, and fe, inherent in the DM-redshift relation. Our proposal opens new possibilities for FRB cosmology, while it requires extensive galaxy redshift catalogues and further improvement of the halo model....
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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 $\sim\! 80\%$ 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. The data release website is <https://hsc-release.mtk.nao.ac.jp>....
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Monthly Notices of the Royal Astronomical Society 511(1) 1131-1140 2022年3月The high-precision measurement of spatial clustering of emission-line galaxies (ELGs) is a primary objective for upcoming cosmological spectroscopic surveys. The source of strong emission of ELGs is nebular emission from surrounding ionized gas irradiated by massive short-lived stars in star-forming galaxies. As a result, ELGs are more likely to reside in newly formed haloes and this leads to a non-linear relation between ELG number density and matter density fields. In order to estimate the covariance matrix of cosmological observables, it is essential to produce many independent realizations to simulate ELG distributions for large survey volumes. To this end, we present a novel and fast scheme to populate ELGs in dark-matter only N-body simulations based on local density field. This method enables fast production of mock ELG catalogues suitable for verifying analysis methods and quantifying observational systematics in upcoming spectroscopic surveys and can populate ELGs in moderately high-density regions even though the halo structure cannot be resolved due to low resolution. The power spectrum of simulated ELGs is consistent with results of hydrodynamical simulations up to fairly small scales ($\lesssim 1 h \, \mathrm{Mpc}^{-1}$), and the simulated ELGs are more likely to be found in filamentary structures, which is consistent with results of semi-analytic and hydrodynamical simulations. Furthermore, we address the redshift-space power spectrum of simulated ELGs. The measured multipole moments of simulated ELGs clearly exhibit a weaker Finger-of-God effect than those of matter due to infalling motions towards halo centre, rather than random virial motions inside haloes....
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Monthly Notices of the Royal Astronomical Society 2022年3月The high-precision measurement of spatial clustering of emission line galaxies (ELGs) is a primary objective for upcoming cosmological spectroscopic surveys. The source of strong emission of ELGs is nebular emission from surrounding ionized gas irradiated by massive stars and such massive short-lived stars form in star-forming galaxies. As a result, ELGs are more likely to reside in newly-formed halos and this leads to a nonlinear relation between ELG number density and matter density fields. In order to estimate the covariance matrix of cosmological observables, it is essential to produce many independent realisations to simulate ELG distributions for large survey volumes. In order to efficiently generate mock ELG catalogues, we present a novel and fast scheme to populate ELGs to dark-matter only $N$-body simulations based on local density field. This method enables fast production of mock ELG catalogues suitable for upcoming spectroscopic surveys and can populate ELGs in moderately high-density regions even though the halo structure cannot be resolved due to low resolution. The simulated ELGs are more likely to be found in filamentary structures, which is consistent with results of semi-analytic and hydrodynamical simulations. Furthermore, we address the redshift-space power spectrum of simulated ELGs. The measured multipole moments clearly exhibit a weaker Finger-of-God effect due to infalling motion towards halo centre, which is predicted by the simulations....
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Physical Review D 104(10) 2021年11月Perturbation theory of large-scale structures of the Universe at next-to-leading order and next-to-next-to-leading order provides us with predictions of cosmological statistics at subpercent level in the mildly nonlinear regime. Its use to infer cosmological parameters from spectroscopic surveys, however, is hampered by the computational cost of making predictions for a large number of parameters. In order to reduce the running time of the codes, we present a fast scheme in the context of the regularized perturbation theory approach and applied it to power spectra at 2-loop level and bispectra at 1-loop level, including the impact of binning. This method utilizes a Taylor expansion of the power spectrum as a functional of the linear power spectrum around fiducial points at which costly direct evaluation of perturbative diagrams is performed and tabulated. The computation of the predicted spectra for arbitrary cosmological parameters then requires only one-dimensional integrals that can be done within a few minutes. It makes this method suitable for Markov chain Monte-Carlo analyses for cosmological parameter inference....
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The Astrophysical Journal 2021年8月Emission line galaxies (ELGs), more generally star-forming galaxies, are valuable tracers of large-scale structure and therefore main targets of upcoming wide-area spectroscopic galaxy surveys. We propose a fixed-aperture shape estimator of each ELG for extracting the intrinsic alignment (IA) signal, and assess the performance of the method using image simulations of ELGs generated from the IllustrisTNG simulation including observational effects such as the sky background noise. We show that our method enables a significant detection of the IA power spectrum with the linear-scale coefficient AIA ≃ (13-15) ± 3.0 up to z = 2, even from the small simulation volume $\sim 0.009{({h}^{-1}\,\mathrm{Gpc})}^{3}$ , in contrast to the null detection with the standard method. Thus the ELG IA signal, measured with our method, opens up opportunities to exploit cosmology and galaxy physics in high-redshift universe....
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Publications of the Astronomical Society of Japan 2021年8月We study the angular correlation function of star-forming galaxies and properties of their host dark matter halos at z > 1 using the Hyper-Suprime Cam (HSC) Subaru Stragetic Program (SSP) survey. We use [O II] emitters identified using two narrow-band (NB) filters, NB816 and NB921, in the Deep/UltraDeep layers, which respectively cover large angular areas of 16.3 deg2 and 16.9 deg2. Our sample contains 8302 and 9578 [O II] emitters at z = 1.19 (NB816) and z = 1.47 (NB921), respectively. We detect a strong clustering signal over a wide angular range, $0{_{.}^{\circ } } 001$ < θ < 1 °, with bias $b=1.61^{+0.13}_{-0.11}$ (z = 1.19) and $b=2.09^{+0.17}_{-0.15}$ (z = 1.47). We also find a clear deviation of the correlation from a simple power-law form. To interpret the measured clustering signal, we adopt a halo occupation distribution (HOD) model that is constructed to explain the spatial distribution of galaxies selected by star formation rate. The observed correlation function and number density are simultaneously explained by the best-fitting HOD model. From the constrained HOD model, the average mass of halos hosting the [O II] emitters is derived to be $\log {M_{\rm eff}/(h^{-1}\, {M}_{\odot })}=12.70^{+0.09}_{-0.07}$ and $12.61^{+0.09}_{-0.05}$ at z = 1.19 and 1.47, respectively, which will become halos with the present-day mass M ~ 1.5 × 1013 h-1 M⊙. The satellite fraction of the [O II] emitter sample is found to be fsat ~ 0.15. All these values are consistent with previous studies of similar samples, but we obtain tighter constraints even in a larger parameter space due to the larger sample size from the HSC. The results obtained for host halos of [O II] emitters in this paper enable the construction of mock galaxy catalogs and the systematic forecast study of cosmological constraints from upcoming emission line galaxy surveys such as the Subaru Prime Focus Spectrograph survey....
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Physical Review D 104(10) 1-31 2021年7月 査読有りPerturbation theory of large-scale structures of the Universe at next-to-leading order and next-to-next-to-leading order provides us with predictions of cosmological statistics at sub-percent level in the mildly non-linear regime. Its use to infer cosmological parameters from spectroscopic surveys, however, is hampered by the computational cost of making predictions for a large number of parameters. In order to reduce the running time of the codes, we present a fast scheme in the context of the regularized perturbation theory approach and applied it to power spectra at 2-loop level and bispectra at 1-loop level, including the impact of binning. This method utilizes a Taylor expansion of the power spectrum as a functional of the linear power spectrum around fiducial points at which costly direct evaluation of perturbative diagrams is performed and tabulated. The computation of the predicted spectra for arbitrary cosmological parameters then requires only one-dimensional integrals that can be done within a few minutes. It makes this method suitable for Markov chain Monte-Carlo analyses for cosmological parameter inference....
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Publications of the Astronomical Society of Japan 73(3) 772 2021年6月...
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Monthly Notices of the Royal Astronomical Society 2021年4月We study the effect of baryonic processes on weak lensing (WL) observables with a suite of mock WL maps, the κTNG, based on the cosmological hydrodynamic simulations IllustrisTNG. We quantify the baryonic effects on the WL angular power spectrum, one-point probability distribution function (PDF), and number counts of peaks and minima. We also show the redshift evolution of the effects, which is a key to distinguish the effect of baryons from fundamental physics such as dark energy, dark matter, and massive neutrinos. We find that baryonic processes reduce the small-scale power, suppress the tails of the PDF, peak and minimum counts, and change the total number of peaks and minima. We compare our results to existing semi-analytical models and hydrodynamic simulations, and discuss the source of discrepancies. The κTNG suite includes 10 000 realizations of $5 \times 5 \, \mathrm{deg}^2$ maps for 40 source redshifts up to zs = 2.6, well covering the range of interest for existing and upcoming WL surveys. We also produce the κTNG-Dark suite of maps, generated based on the corresponding dark matter-only IllustrisTNG simulations. Our mock maps are not only suitable for developing analytical models that incorporate the effect of baryons, but also particularly useful for studies that rely on mass maps, such as non-Gaussian statistics and machine learning with convolutional neural networks. The suite of mock maps is publicly available at Columbia Lensing (http://columbialensing.org)....
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Journal of Cosmology and Astroparticle Physics 2021(3) 2021年3月We present the 3-dimensional intrinsic alignment power spectra between the projected 2d galaxy shape/spin and the 3d tidal field across 0.1<k/<60 using cosmological hydrodynamical simulation, Illustris-TNG300, at redshifts ranging from 0.3 to 2. The shape-tidal field alignment increases with galaxy mass and the linear alignment coefficient AIA, defined with respect to the primordial tidal field, is found to have weak redshift dependence. We also show a promising detection of the shape/spin-tidal field alignments for stellar mass limited samples and a weak or almost null signal for star-forming galaxies for the TNG300 volume, ∼ 0.01 (h-1 Gpc)3. We further study the morphology and environmental dependence of the intrinsic alignment power spectra. The shape of massive disk- and spheroid-galaxies tend to align with the tidal field. The spin of low mass disks (and spheroids at low redshifts) tend to be parallel with the tidal field, while the spin of massive spheroids and disks tend to be perpendicular to tidal field. The shape and spin of massive centrals align with the tidal field at both small and large scales. Satellites show a radial alignment within the one-halo term region, and low mass satellites have an intriguing alignment signal in the two-halo term region. We also forecast a feasibility to measure the intrinsic alignment power spectrum for spectroscopic and imaging surveys such as Subaru HSC/PFS and DESI. Our results thus suggest that galaxy intrinsic alignment can be used as a promising tool for constraining the galaxy formation models....
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Physical Review D 2021年3月The thermal Sunyaev-Zel'dovich (tSZ) effect is a powerful probe of cosmology. The statistical errors in the tSZ power spectrum measurements are dominated by the presence of massive clusters in a survey volume that are easy to identify on an individual cluster basis. First, we study the impact of super sample covariance (SSC) on the tSZ power spectrum measurements, and find that the sample variance is dominated by the connected non-Gaussian (cNG) covariance arising mainly from Poisson number fluctuations of massive clusters in the survey volume. Second, we find that removing such individually detected, massive clusters from the analysis significantly reduces the cNG contribution, thereby causing the SSC to be a leading source of the sample variance. We then show, based on a Fisher analysis, that the power spectrum measured from the remaining diffuse tSZ effects can be used to obtain tight constraints on cosmological parameters as well as the hydrostatic mass bias parameter. Our method allows the use of both individual tSZ cluster counts and the power spectrum measurements of diffuse tSZ signals for cosmology and intracluster gas physics....
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Monthly Notices of the Royal Astronomical Society 501(1) 833-852 2021年2月We use a suite of N-body simulations to study intrinsic alignments (IA) of halo shapes with the surrounding large-scale structure in the ΛCDM model. For this purpose, we develop a novel method to measure multipole moments of the three-dimensional power spectrum of the E-mode field of halo shapes with the matter/halo distribution, $P_{\delta E}^{(\ell)}(k)$ (or $P^{(\ell)}_{ { \rm h}E}$ ), and those of the auto-power spectrum of the E-mode, $P^{(\ell)}_{EE}(k)$ , based on the E/B-mode decomposition. The IA power spectra have non-vanishing amplitudes over the linear to non-linear scales, and the large-scale amplitudes at k ≲ 0.1 h-1 Mpc are related to the matter power spectrum via a constant coefficient (AIA), similar to the linear bias parameter of galaxy or halo density field. We find that the cross- and auto-power spectra PδE and PEE at non-linear scales, k ≳ 0.1 h-1 Mpc, show different k-dependences relative to the matter power spectrum, suggesting a violation of the non-linear alignment model commonly used to model contaminations of cosmic shear signals. The IA power spectra exhibit baryon acoustic oscillations, and vary with halo samples of different masses, redshifts, and cosmological parameters (Ωm, S8). The cumulative signal-to-noise ratio for the IA power spectra is about 60 per cent of that for the halo density power spectrum, where the super-sample covariance is found to give a significant contribution to the total covariance. Thus our results demonstrate that the IA power spectra of galaxy shapes, measured from imaging and spectroscopic surveys for an overlapping area of the sky, can be used to probe the underlying matter power spectrum, the primordial curvature perturbations, and cosmological parameters, in addition to the standard galaxy density power spectrum....
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Physical Review D 102(6) 2020年9月An accurate theoretical template of the redshift-space galaxy power spectrum, if applicable out to nonlinear scales, enables us to extract more stringent and robust constraints on cosmological parameters from the measured galaxy clustering. In this work, we develop a simulation-based template, so-called emulator, for the redshift-space power spectrum of dark matter halos. Using the redshift-space halo power spectra measured from the DARK QUEST N -body simulation suite that covers 101 flat-geometry w -cold dark matter (w CDM ) cosmologies around the Planck Λ CDM model, we feed these data into a feed-forward neural network to build the fast and accurate emulation of the power spectrum from the linear to nonlinear scales up to k ≃0.6 h Mpc-1 . Our emulator achieves about 1% and 5% fractional accuracies in predicting the monopole and quadrupole moments of the power spectrum, respectively, for halos of ∼1013h-1 M☉ that correspond to host halos of the Sloan Digital Sky Survey (SDSS) LOWZ- and CMASS (constant mass)-like galaxies, where the achieved accuracies are sufficient compared to the statistical errors of SDSS volume. The validation and performance of the emulator are given by the comparison of the emulator predictions with the power spectra directly measured from the simulations for validation sets that are not used in the training. We demonstrate that the emulator outputs can be used to make model predictions for the redshift-space power spectrum of galaxies by employing user-fed models for the halo-galaxy connection, such as the halo occupation distribution. The emulator allows us to easily incorporate the Finger-of-God effect due to the virial motions of galaxies and the Alcock-Paczyński distortions. Our code can compute the redshift-space galaxy power spectrum in a CPU subseconds and is ready to perform the emulator-based cosmological analysis for the exiting and upcoming galaxy redshift surveys....
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Monthly Notices of the Royal Astronomical Society 496(4) 4468-4487 2020年8月An optical cluster finder inevitably suffers from projection effects, where it misidentifies a superposition of galaxies in multiple haloes along the line of sight as a single cluster. Using mock cluster catalogues built from cosmological N-body simulations, we quantify the impact of these projection effects with a particular focus on the observables of interest for cluster cosmology, namely the cluster-lensing and the cluster-clustering signals. We find that 'observed' clusters, I.e. clusters identified by our cluster finder algorithm, exhibit lensing and clustering signals that deviate from expectations based on a statistically isotropic halo model - while both signals agree with halo model expectations on small scales, they show unexpected boosts on large scales by up to a factor of 1.2 or 1.4, respectively. We identify the origin of these boosts as the inherent selection bias of optical cluster finders for clusters embedded within filaments aligned with the line of sight and show that a minority ( $\sim 30{ { \ \rm per\ cent } }$ ) of such clusters within the entire sample is responsible for this observed boost. We discuss the implications of our results on previous studies of optical cluster, as well as prospects for identifying and mitigating projection effects in future cluster cosmology analyses....
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Publications of the Astronomical Society of Japan 72(4) 2020年8月Recent constraints on the splashback radius around optically selected galaxy clusters from the redMaPPer cluster-finding algorithm in the literature have shown that the observed splashback radius is ${\sim}20\%$ smaller than that predicted by N-body simulations. We present analyses on the splashback features around ∼ 3000 optically selected galaxy clusters detected by the independent cluster-finding algorithm CAMIRA over a wide redshift range of 0.1 < zcl < 1.0 from the second public data release of the Hyper Suprime-Cam (HSC) Subaru Strategic Program covering ∼427 deg2 for the cluster catalog. We detect the splashback feature from the projected cross-correlation measurements between the clusters and photometric galaxies over the wide redshift range, including for high-redshift clusters at 0.7 < zcl < 1.0, thanks to deep HSC images. We find that constraints from red galaxy populations only are more precise than those without any color cut, leading to 1σ precisions of ${\sim}15\%$ at 0.4 < zcl < 0.7 and 0.7 < zcl < 1.0. These constraints at 0.4 < zcl < 0.7 and 0.7 < zcl < 1.0 are more consistent with the model predictions (≲1σ) than their $20\%$ smaller values as suggested by the previous studies with the redMaPPer (∼2σ). We also investigate selection effects of the optical cluster-finding algorithms on the observed splashback features by creating mock galaxy catalogs from a halo occupation distribution model, and find such effects to be sub-dominant for the CAMIRA cluster-finding algorithm. We also find that the redMaPPer-like cluster-finding algorithm induces a smaller inferred splashback radius in our mock catalog, especially at lower richness, which can well explain the smaller splashback radii in the literature. In contrast, these biases are significantly reduced when increasing its aperture size. This finding suggests that aperture sizes of optical cluster finders that are smaller than splashback feature scales can induce significant biases on the inferred location of a splashback radius....
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Monthly Notices of the Royal Astronomical Society 2020年7月We present a novel statistic to extract cosmological information in weak lensing data: the lensing minima. We also investigate the effect of baryons on cosmological constraints from peak and minimum counts. Using the MassiveNuS simulations, we find that lensing minima are sensitive to non-Gaussian cosmological information and are complementary to the lensing power spectrum and peak counts. For an LSST-like survey, we obtain 95 per cent credible intervals from a combination of lensing minima and peaks that are significantly stronger than from the power spectrum alone, by 44 per cent, 11 per cent, and 63 per cent for the neutrino mass sum ∑mν, matter density Ωm, and amplitude of fluctuation As, respectively. We explore the effect of baryonic processes on lensing minima and peaks using the hydrodynamical simulations BAHAMAS and Osato15. We find that ignoring baryonic effects would lead to strong (≍4σ) biases in inferences from peak counts, but negligible (≍0.5σ) for minimum counts, suggesting lensing minima are a potentially more robust tool against baryonic effects. Finally, we demonstrate that the biases can in principle be mitigated without significantly degrading cosmological constraints when we model and marginalize the baryonic effects....
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The Astrophysical Journal 895(2) 2020年6月We provide a new fitting formula of the matter bispectrum in the nonlinear regime calibrated by high-resolution cosmological N-body simulations of 41 cold dark matter (wCDM, w = constant) models around the Planck 2015 best-fit parameters. As the parameterization in our fitting function is similar to that in Halofit, our fitting is named BiHalofit. The simulation volume is sufficiently large ( $\gt 10\,{\mathrm{Gpc } }^{3}$ ) to cover almost all measurable triangle bispectrum configurations in the universe. The function is also calibrated using one-loop perturbation theory at large scales ( $k\lt 0.3\,h\,{\mathrm{Mpc } }^{-1}$ ). Our formula reproduced the matter bispectrum to within 10% (15%) accuracy in the Planck 2015 model at wavenumber $k\lt 3\,(10)\,h\,{\mathrm{Mpc } }^{-1}$ and redshifts z = 0-3. The other 40 wCDM models obtained poorer fits, with accuracy approximating 20% at $k\lt 3\,h\,{\mathrm{Mpc } }^{-1}$ and $z=0\mbox{--}1.5$ (the deviation includes the 10%-level sample variance of the simulations). We also provide a fitting formula that corrects the baryonic effects such as radiative cooling and active galactic nucleus feedback, using the latest hydrodynamical simulation IllustrisTNG. We demonstrate that our new formula more accurately predicts the weak-lensing bispectrum than the existing fitting formulae. This formula will assist current and future weak-lensing surveys and cosmic microwave background lensing experiments. Numerical codes of the formula are available, written in Python (https://toshiyan.github.io/clpdoc/html/basic/basic.html#module-basic.bispec), C, and Fortran (http://cosmo.phys.hirosaki-u.ac.jp/takahasi/codes_e.htm)....
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Monthly Notices of the Royal Astronomical Society 492(4) 4780-4804 2020年3月Cross-correlation analysis of the thermal Sunyaev-Zel'dovich (tSZ) effect and weak gravitational lensing (WL) provides a powerful probe of cosmology and astrophysics of the intracluster medium. We present the measurement of the cross-correlation of tSZ and WL from Planck and Subaru Hyper-Suprime Cam. The combination enables us to study cluster astrophysics at high redshift. We use the tSZ-WL cross-correlation and the tSZ autopower spectrum measurements to place a tight constraint on the hydrostatic mass bias, which is a measure of the degree of non-thermal pressure support in galaxy clusters. With the prior on cosmological parameters derived from the analysis of the cosmic microwave background anisotropies by Planck and taking into account foreground contributions both in the tSZ autopower spectrum and the tSZ-WL cross-correlation, the hydrostatic mass bias is estimated to be 26.9^{+8.9}_{-4.4} per cent (68 per cent CL), which is consistent with recent measurements by mass calibration techniques....
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Proceedings of SPIE - The International Society for Optical Engineering 11444 2020年We are studying an improved DIOS (Diffuse Intergalactic Oxygen Surveyor) program, Super DIOS, which is accepted for establishing the Research Group in ISAS/JAXA, for a launch year after 2030. The aim of Super DIOS is an X-ray quantitative exploration of”dark baryon” over several scales from circumgalactic medium, cluster outskirt to warm-hot intergalactic medium along the Cosmic web with mapping redshifted emission lines from mainly oxygen and other ions. These observations play key roles for investigating the physical condition, such as the energy flow and metal circulation, of most baryons in the Universe. This mission will perform wide field X-ray spectroscopy with a field of view of about 0.5-1 degree and energy resolution of a few eV with TES microcalorimeter, but with much improved angular resolution of about 10-15 arcseconds. We will also consider including a small gamma-ray burst monitor and a fast repointing system. We will have an international collaboration with US and Europe for all the onboard instruments.
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Publications of the Astronomical Society of Japan 71(6) 2019年12月This paper presents the second data release of the Hyper Suprime-Cam Subaru Strategic Program, a wide-field optical imaging survey using the 8.2 m Subaru Telescope. The release includes data from 174 nights of observation through 2018 January. The Wide layer data cover about 300 deg^2 in all five broad-band filters (grizy) to the nominal survey exposure (10 min in gr and 20 min in izy). Partially observed areas are also included in the release; about 1100 deg^2 is observed in at least one filter and one exposure. The median seeing in the i-band is {0.^' ' }6}, demonstrating the superb image quality of the survey. The Deep (26 deg^2) and UltraDeep (4 deg^2) data are jointly processed and the UltraDeep-COSMOS field reaches an unprecedented depth of i∼ 28 at 5 σ for point sources. In addition to the broad-band data, narrow-band data are also available in the Deep and UltraDeep fields. This release includes a major update to the processing pipeline, including improved sky subtraction, PSF modeling, object detection, and artifact rejection. The overall data quality has been improved, but this release is not without problems; there is a persistent deblender problem as well as new issues with masks around bright stars. The user is encouraged to review the issue list before utilizing the data for scientific explorations. All the image products as well as catalog products are available for download. The catalogs are also loaded into a database, which provides an easy interface for users to retrieve data for objects of interest. In addition to these main data products, detailed galaxy shape measurements withheld from Public Data Release 1 (PDR1) are now available to the community. The shape catalog is drawn from the S16A internal release, which has a larger area than PDR1 (160 deg^2). All products are available at the data release site, https://hsc-release.mtk.nao.ac.jp/....
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Publications of the Astronomical Society of Japan 71(5) 2019年10月Constraining the relation between the richness N and the halo mass M over a wide redshift range for optically selected clusters is a key ingredient for cluster-related science in optical surveys, including the Subaru Hyper Suprime-Cam (HSC) survey. We measure stacked weak-lensing profiles around 1747 HSC CAMIRA clusters over a redshift range of 0.1 ≤ zcl ≤ 1.0 with N ≥ 15 using the HSC first-year shear catalog covering ˜140 deg2. The exquisite depth and image quality of the HSC survey allow us to measure lensing signals around high-redshift clusters at 0.7 ≤ zcl ≤ 1.0 with a signal-to-noise ratio of 19 within the comoving radius range 0.5≲ R≲ 15 h^{-1}Mpc. We constrain the richness-mass relations P(ln N ∣ M, z) of HSC CAMIRA clusters assuming a log-normal distribution without informative priors on model parameters, by jointly fitting to the lensing profiles and abundance measurements under both Planck and WMAP cosmological models. We show that our model gives acceptable p-values when we add redshift-dependent terms proportional to ln (1 + z) and [ln (1 + z)]2 in the mean and scatter relations of P(ln N ∣ M, z). Such terms presumably originate from the variation of photometric redshift errors as a function of redshift. We show that constraints on the mean relation <M ∣ N> are consistent between the Planck and WMAP models, whereas the scatter values σln M ∣ N for the Planck model are systematically larger than those for the WMAP model. We also show that the scatter values for the Planck model increase toward lower richness values, whereas those for the WMAP model are consistent with constant values as a function of richness. This result highlights the importance of the scatter in the mass-richness relation for cluster cosmology....
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The Astrophysical Journal 884(1) 2019年10月We perform an ensemble of N-body simulations with 20483 particles for 101 flat wCDM cosmological models sampled based on a maximin distance sliced Latin hypercube design. By using the halo catalogs extracted at multiple redshifts in the range of z = [0,1.48], we develop DARK EMULATOR, which enables fast and accurate computations of the halo mass function, halo-matter cross-correlation, and halo autocorrelation as a function of halo masses, redshift, separations, and cosmological models based on principal component analysis and Gaussian process regression for the large-dimensional input and output data vector. We assess the performance of the emulator using a validation set of N-body simulations that are not used in training the emulator. We show that, for typical halos hosting CMASS galaxies in the Sloan Digital Sky Survey, the emulator predicts the halo-matter cross-correlation, relevant for galaxy-galaxy weak lensing, with an accuracy better than 2% and the halo autocorrelation, relevant for galaxy clustering correlation, with an accuracy better than 4%. We give several demonstrations of the emulator. It can be used to study properties of halo mass density profiles such as the concentration-mass relation and splashback radius for different cosmologies. The emulator outputs can be combined with an analytical prescription of halo-galaxy connection, such as the halo occupation distribution at the equation level, instead of using the mock catalogs to make accurate predictions of galaxy clustering statistics, such as galaxy-galaxy weak lensing and the projected correlation function for any model within the wCDM cosmologies, in a few CPU seconds....
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The Astrophysical Journal 875(1) 2019年4月We present weak-lensing measurements using the first-year data from the Hyper Suprime-Cam Strategic Survey Program on the Subaru telescope for eight galaxy clusters selected through their thermal Sunyaev-Zel’dovich (SZ) signal measured at 148 GHz with the Atacama Cosmology Telescope Polarimeter experiment. The overlap between the two surveys in this work is 33.8 square degrees, before masking bright stars. The signal-to-noise ratio of individual cluster lensing measurements ranges from 2.2 to 8.7, with a total of 11.1 for the stacked cluster weak-lensing signal. We fit for an average weak-lensing mass distribution using three different profiles, a Navarro-Frenk-White profile, a dark-matter-only emulated profile, and a full cosmological hydrodynamic emulated profile. We interpret the differences among the masses inferred by these models as a systematic error of 10%, which is currently smaller than the statistical error. We obtain the ratio of the SZ-estimated mass to the lensing-estimated mass (the so-called hydrostatic mass bias 1-b) of {0.74}-0.12+0.13, which is comparable to previous SZ-selected clusters from the Atacama Cosmology Telescope and from the Planck Satellite. We conclude with a discussion of the implications for cosmological parameters inferred from cluster abundances compared to cosmic microwave background primary anisotropy measurements....
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Physical Review D 99(6) 2019年3月We study the accuracy with which cosmological parameters can be determined from a real space power spectrum of matter density contrast at weakly nonlinear scales using analytical approaches. From power spectra measured in N -body simulations and using the Markov chain Monte Carlo technique, the best-fitting cosmological input parameters are determined with several analytical methods as a theoretical template, such as the standard perturbation theory, the regularized perturbation theory, and the effective field theory. We show that at redshift 1, all two-loop level calculations can fit the measured power spectrum down to scales k ∼0.2 h Mpc-1 , and cosmological parameters are successfully estimated in an unbiased way. Introducing the figure of bias (FoB) and figure of merit (FoM) parameter, we determine the validity range of those models and then evaluate their relative performances. With one free parameter, namely the damping scale, the regularized perturbation theory is found to be able to provide the largest FoM parameter while keeping the FoB in the acceptance range....
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Journal of Low Temperature Physics 193(5-6) 1016-1023 2018年12月The updated program of the future Japanese X-ray satellite mission Diffuse Intergalactic Oxygen Surveyor (DIOS), called as Super DIOS, is planned to search for dark baryons in the form of warm-hot intergalactic medium (WHIM) with high-resolution X-ray spectroscopy. The mission will detect redshifted emission lines from OVII, OVIII and other ions, leading to an overall understanding of the physical nature and spatial distribution of dark baryons as a function of cosmological timescale. We have started the conceptual design of the satellite and onboard instruments, focusing on the era of 2030s. The major change will be an improved angular resolution of the X-ray telescope. Super DIOS will have a 10-arcsec resolution, which is an improvement by a factor of about 20 over DIOS. With this resolution, most of the contaminating X-ray sources will be separated, and the level of the diffuse X-ray background will be much reduced after subtraction of point sources. This will give us higher sensitivity to map out the WHIM in emission....
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Physical Review D 2018年10月Gravitational waves from inspiraling compact objects provide us with information of the distance scale since we can infer the absolute luminosity of the source from analysis of the wave form, which is known as standard sirens. The first detection of the gravitational wave signal of the binary black hole merger event by Advanced LIGO has opened up the possibility of utilizing standard sirens as cosmological probe. In order to extract information of the distance-redshift relation, we cross-correlate weak lensing, which is an unbiased tracer of matter distribution in the Universe, with the projected number density of gravitational wave sources. For weak lensing, we employ tomography technique to efficiently obtain information of large-scale structures at wide ranges of redshifts. Making use of the cross-correlations along with the autocorrelations, we present forecast of constraints on four cosmological parameters, i.e., Hubble parameter, matter density, the equation of state parameter of dark energy, and the amplitude of matter fluctuation. To fully explore the ability of cross-correlations, which require large overlapping sky coverage, we consider the specific case with the upcoming surveys by Euclid for weak lensing and Einstein Telescope for standard sirens. We show that cosmological parameters can be tightly constrained solely by these auto- and cross-correlations of standard sirens and weak lensing. For example, the 1 -σ error of Hubble parameter is expected to be σ (H0)=0.33 km s-1 Mpc-1 . Thus, the proposed statistics will be a promising probe into the distance scale....
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Physical Review D 98(2) 2018年7月We investigate the splashback features of dark-matter halos based on cosmic density and velocity fields. Besides the density correlation function binned by the halo orientation angle, which was used in the literature, we introduce, for the first time, the corresponding velocity statistic, alignment momentum correlation function, to take into account the asphericity of halos. Using large-volume, high-resolution N -body simulations, we measure the alignment statistics of density and velocity. On halo scales, x ∼R200 m∼1 h-1 Mpc , we detect a sharp steepening in the momentum correlation associated with the physical halo boundary, or the splashback feature, which is found more prominent than in the density correlation. We also find that the splashback radius determined from the density correlation becomes ∼3.5 % smaller than that from the momentum correlation, with their correlation coefficient being 0.605. Moreover, the orientation-dependent splashback feature due to halo asphericity is measured when the density profile is determined by dark-matter particles, which can be used as a test of collisional cold dark matter since the halo shape is predicted to be rounder in such a model....
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Monthly Notices of the Royal Astronomical Society 477(2) 2128-2140 2018年6月We study the dependence of surface mass density profiles, which can be directly measured by weak gravitational lensing, on the orientation of haloes with respect to the line-of-sight direction, using a suite of N-body simulations. We find that, when major axes of haloes are aligned with the line-of-sight direction, surface mass density profiles have higher amplitudes than those averaged over all halo orientations, over all scales from 0.1 to 100 Mpc h-1 we studied. While the orientation dependence at small scales is ascribed to the halo triaxiality, our results indicate even stronger orientation dependence in the so-called two-halo regime, up to 100 Mpc h-1. The orientation dependence for the two-halo term is well approximated by a multiplicative shift of the amplitude and therefore a shift in the halo bias parameter value. The halo bias from the two-halo term can be overestimated or underestimated by up to ∼ 30 per cent depending on the viewing angle, which translates into the bias in estimated halo masses by up to a factor of 2 from halo bias measurements. The orientation dependence at large scales originates from the anisotropic halo-matter correlation function, which has an elliptical shape with the axis ratio of ∼0.55 up to 100 Mpc h-1. We discuss potential impacts of halo orientation bias on other observables such as optically selected cluster samples and a clustering analysis of large-scale structure tracers such as quasars....
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Monthly Notices of the Royal Astronomical Society 2018年3月Recent detections of the cross-correlation of the thermal Sunyaev-Zel'dovich (tSZ) effect and weak gravitational lensing (WL) enable unique studies of cluster astrophysics and cosmology. In this work, we present constraints on the amplitude of the non-thermal pressure fraction in galaxy clusters, α0, and the amplitude of the matter power spectrum, σ8, using measurements of the tSZ power spectrum from Planck, and the tSZ-WL cross-correlation from Planck and the Red Cluster Sequence Lensing Survey. We fit the data to a semi-analytic model with the covariance matrix using N-body simulations. We find that the tSZ power spectrum alone prefers σ8 ∼ 0.85 and a large fraction of non-thermal pressure (α0 ∼ 0.2-0.3). The tSZ-WL cross-correlation on the other hand prefers a significantly lower σ8 ∼ 0.6 and low α0 ∼ 0.05. We show that this tension can be mitigated by allowing for a steep slope in the stellar mass-halo mass relation, which would cause a reduction of the gas in low-mass haloes. In such a model, the combined data prefer σ8 ∼ 0.7 and α0 ∼ 0.2, consistent with predictions from hydrodynamical simulations....
書籍等出版物
2講演・口頭発表等
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2nd HSC Medium-band Filter Workshop 2024年11月27日
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Theory and Data Analysis Challenges for Cosmological Large-Scale Structure Observations 2024年11月19日
担当経験のある科目(授業)
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2024年12月 - 2025年1月機械学習実践入門 (千葉大学)
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2024年10月 - 2025年1月電磁気学基礎演習1 (千葉大学)
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2024年4月 - 2024年7月先進科学セミナーIIIA（統計力学） (千葉大学)
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2024年4月 - 2024年7月先進科学セミナーIA（微分積分・線形代数） (千葉大学)
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2023年12月 - 2024年1月機械学習実践入門 (千葉大学)
所属学協会
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2023年4月 - 現在
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2019年4月 - 現在
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2019年4月 - 現在
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2016年4月 - 現在
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2016年1月 - 現在
共同研究・競争的資金等の研究課題
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日本学術振興会 科学研究費助成事業 2024年4月 - 2029年3月
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日揮・実吉奨学会 2024年9月 - 2025年8月
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日本学術振興会 科学研究費助成事業 若手研究 2022年4月 - 2025年3月
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日本科学協会 笹川科学研究助成 2024年4月 - 2025年2月
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日本学術振興会 科学研究費助成事業 特別研究員奨励費 2021年4月 - 2023年3月