Updated on 2023/12/22

写真a

 
Takahashi Ryuichi
 
Affiliation
Graduate School of Science and Technology Research Division

Degree

  • 博士(理学)

Research Areas

  • Natural Science / Astronomy

  • Natural Science / Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics

Professional Memberships

  • 日本天文学会

  • 日本物理学会

Papers

  • On weak lensing response functions

    D. Munshi, R. Takahashi, J. D. McEwen

    Journal of Cosmology and Astroparticle Physics   ( 010 )   1 - 21   2022.10

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  • Cosmological inference from an emulator based halo model. II. Joint analysis of galaxy-galaxy weak lensing and galaxy clustering from HSC-Y1 and SDSS

    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, 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 )   083520-1 - 083520-39   2022.10

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  • Cosmological inference from an emulator based halo model. I. Validation tests with HSC and SDSS mock catalogs

    Hironao Miyatake, Yosuke Kobayashi, Masahiro Takada, Takahiro Nishimichi, Masato Shirasaki, Sunao Sugiyama, Ryuichi Takahashi, Ken Osato, Surhud More, Youngsoo Park

    Physical Review D   ( 106 )   083519-1 - 083519-36   2022.10

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  • Separate universe approach to evaluate nonlinear matter power spectrum for nonflat ΛCDM model

    Ryo Terasawa, Ryuichi Takahashi, Takahiro Nishimichi, Masahiro Takada

    Physical Review D   ( 106 )   083504-1 - 083504-18   2022.10

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  • Amplitude and phase fluctuations of gravitational waves magnified by strong gravitational lensing

    Masamune Oguri, Ryuichi Takahashi

    Physical Review D   ( 106 )   043532-1 - 043532-9   2022.8

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  • HSC Year 1 cosmology results with the minimal bias method: HSC×BOSS galaxy-galaxy weak lensing and BOSS galaxy clustering

    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 )   123537-1 - 123537-23   2022.6

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  • A new estimator for phase statistics

    D. Munshi, R. Takahashi, J. D. McEwen, T. D. Kitching, F. R. Bouchet

    Journal of Cosmology and Astroparticle Physics   ( 005 )   1 - 16   2022.5

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  • Probing cosmology and gastrophysics with fast radio bursts: Cross-correlations of dark matter haloes and cosmic dispersion measures

    Masato Shirasaki, Ryuichi Takahashi, Ken Osato, Kunihito Ioka

    2022.2

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  • Cosmological boost factor for dark matter annihilation at redshifts of z=10−100 using the power spectrum approach

    Ryuichi Takahashi, Kazunori Kohri

    2021.11

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    arXiv

  • Impacts of new small-scale N -body simulations on dark matter annihilations constrained from cosmological 21-cm line observations

    Nagisa Hiroshima, Kazunori Kohri, Toyokazu Sekiguchi, Ryuichi Takahashi

    2021.10

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    arXiv

  • Statistical modelling of the cosmological dispersion measure

    Ryuichi Takahashi,Kunihito Ioka, Asuka Mori, Koki Funahashi

    502 ( 2 )   2615 - 2629   2021.4

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  • Power spectrum of halo intrinsic alignments in simulations

    Toshiki Kurita, Masahiro Takada, Takahiro Nishimichi, Ryuichi Takahashi, Ken Osato, Yosuke Kobayashi

    Monthly Notices of the Royal Astronomical Society   ( 501 )   833   2021.2

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    arXiv

  • Constraining primordial non-Gaussianity with postreconstructed galaxy bispectrum in redshift space

    Masato Shirasaki, Naonori S. Sugiyama, Ryuichi Takahashi, Francisco-Shu Kitaura

    Physical Review D   ( 103 )   023506   2021.1

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    arXiv

  • Covariance of the redshift-space matter power spectrum after reconstruction

    Chiaki Hikage, Ryuichi Takahashi, Kazuya Koyama

    Physical Review D   ( 102 )   083514   2020.9

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    arXiv

  • Accurate emulator for the redshift-space power spectrum of dark matter halos and its application to galaxy power spectrum

    Yosuke Kobayashi, Takahiro Nishimichi, Masahiro Takada, Ryuichi Takahashi, Ken Osato

    Physical Review D   ( 102 )   063504   2020.9

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    arXiv

  • Probing Dark Low-mass Halos and Primordial Black Holes with Frequency-dependent Gravitational Lensing Dispersions of Gravitational Waves

    Masamune Oguri, Ryuichi Takahashi

    The Astrophysical Journal   ( 901 )   58   2020.9

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    arXiv

  • Fitting the Nonlinear Matter Bispectrum by the Halofit Approach

    Ryuichi Takahashi, Takahiro Nishimichi, Toshiya Namikawa, Atsushi Taruya, Issha Kayo, Ken Osato, Yosuke Kobayashi, Masato Shirasaki

    The Astrophysical Journal   ( 895 )   113   2020.6

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    arXiv

  • The weak lensing bispectrum induced by gravity

    D. Munshi, T. Namikawa, T. D. Kitching, J. D. McEwen, R. Takahashi, F. R. Bouchet, A. Taruya, B. Bose

    Monthly Notices of the Royal Astronomical Society   ( 493 )   3985   2020.4

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    arXiv

  • Cross-correlation of the thermal Sunyaev-Zel'dovich effect and weak gravitational lensing: Planck and Subaru Hyper Suprime-Cam first-year data

    Ken Osato, Masato Shirasaki, Hironao Miyatake, Daisuke Nagai, Naoki Yoshida, Masamune Oguri, Ryuichi Takahashi

    Monthly Notices of the Royal Astronomical Society   492 ( 4 )   4780 - 4804   2020.3

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  • Perturbation theory for the redshift-space matter power spectra after reconstruction

    Chiaki Hikage, Kazuya Koyama, Ryuichi Takahashi

    Physical Review D   101 ( 4 )   043510   2020.2

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  • Cosmological information content in redshift-space power spectrum of SDSS-like galaxies in the quasinonlinear regime up to k =0.3 h Mpc-1

    Yosuke Kobayashi, Takahiro Nishimichi, Masahiro Takada, Ryuichi Takahashi

    Physical Review D   101 ( 2 )   023510   2020.1

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  • Dark Quest. I. Fast and Accurate Emulation of Halo Clustering Statistics and Its Application to Galaxy Clustering

    Takahiro Nishimichi, Masahiro Takada, Ryuichi Takahashi, Ken Osato, Masato Shirasaki, Taira Oogi, Hironao Miyatake, Masamune Oguri, Ryoma Murata, Yosuke Kobayashi, Naoki Yoshida

    The Astrophysical Journal   884 ( 1 )   2019.10

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  • Mock galaxy shape catalogues in the Subaru Hyper Suprime-Cam Survey

    Masato Shirasaki, Takashi Hamana, Masahiro Takada, Ryuichi Takahashi, Hironao Miyatake

    Monthly Notices of the Royal Astronomical Society   486 ( 1 )   52 - 69   2019.6

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  • CMB lensing bispectrum: Assessing analytical predictions against full-sky lensing simulations

    Toshiya Namikawa, Benjamin Bose, Francois R. Bouchet, Ryuichi Takahashi, Atsushi Taruya

    Physical Review D   99 ( 6 )   063511   2019.3

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  • Covariances for cosmic shear and galaxy-galaxy lensing in the response approach

    Ryuichi Takahashi, Takahiro Nishimichi, Masahiro Takada, Masato Shirasaki, Kosei Shiroyama

    Monthly Notices of the Royal Astronomical Society   482 ( 3 )   4253 - 4277   2019.1

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  • Impact of nonlinear growth of the large-scale structure on CMB B-mode delensing

    Toshiya Namikawa, Ryuichi Takahashi

    Physical Review D   99 ( 2 )   023530   2019.1

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  • Constraints on the Mass–Richness Relation from the Abundance and Weak Lensing of SDSS Clusters

    R. Murata, T. Nishimichi, M. Takada, H. Miyatake, M. Shirasaki, S. More, R. Takahashi, K. Osato

    The Astrophysical Journal   2018.2

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  • The first-year shear catalog of the Subaru Hyper Suprime-Cam Subaru Strategic Program Survey

    R. Mandelbaum, H. Miyatake, T. Hamana, M. Oguri, M. Simet, R. Armstrong, J. Bosch, R. Murata, F. Lanusse, A. Leauthaud, J. Coupon, S. More, M. Takada, S. Miyazaki, J.S. Speagle, M. Shirasaki, C. Sifon, S. Huang, A.J. Nishizawa, E. Medezinski, Y. Okura, N. Okabe, N. Czakon, R. Takahashi, W. Coulton, C. Hikage, Y. Komiyama, R.H. Lupton, M.A. Strauss, M. Tanaka, Y. Utsumi

    Publications of the Astronomical Society of Japan   2018.1

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  • Full-sky Gravitational Lensing Simulation for Large-area Galaxy Surveys and Cosmic Microwave Background Experiments

    R. Takahashi, T. Hamana, M. Shirasaki, T. Namikawa, T. Nishimichi, K. Osato, K. Shiroyama

    The Astrophysical Journal   2017.11

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  • Robust covariance estimation of galaxy-galaxy weak lensing: validation and limitation of jackknife covariance

    M. Shirasaki, M. Takada, H. Miyatake, R. Takahashi, T. Hamana, T. Nishimichi, R. Murata

    Monthly Notices of the Royal Astronomical Society   2017.9

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  • Arrival Time Differences between Gravitational Waves and Electromagnetic Signals due to Gravitational Lensing

    Ryuichi Takahashi

    The Astrophysical Journal   2017.1

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  • The Subaru FMOS galaxy redshift survey (FastSound). IV. New constraint on gravity theory from redshift space distortions at z~1.4

    T. Okumura, C. Hikage, T. Totani, M. Tonegawa, H. Okada, K. Glazebrook, C. Blake, P.G. Ferreira, S. More, A. Taruya, S. Tsujikawa, M. Akiyama, G. Dalton, T. Goto, T. Ishikawa, F. Iwamuro, T. Matsubara, T. Nishimichi, K. Ohta, I. Shimizu, R. Takahashi, N. Takato, N. Tamura, K. Yabe, N. Yoshida

    Publications of the Astronomical Society of Japan   2016.6

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  • Constraints on small-scale cosmological fluctuations from SNe lensing dispersion

    Ido Ben-Dayan, Ryuichi Takahashi

    Monthly Notices of the Royal Astronomical Society   1 ( 455 )   552 - 562   2016.1

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  • Tension in Amplitudes of Cosmological Density Fluctuations Inferred by Cosmic Microwave Background(CMB)and Measured by Large Scale Structure(LSS)

    Takahashi Ryuichi

    Butsuri   71 ( 9 )   598 - 606   2016

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  • Detection of universality of dark matter profile from Subaru weak lensing measurements of 50 massive clusters

    Hiroko Niikura, Masahiro Takada, Nobuhiro Okabe, Rossella Martino, Ryuichi Takahashi

    Publications of the Astronomical Society of Japan   6 ( 67 )   10324   2015.12

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  • Constraints on warm dark matter from weak lensing in anomalous quadruple lenses

    Kaiki Taro Inoue, Ryuichi Takahashi, Tomo Takahashi, Tomoaki Ishiyama

    Monthly Notices of the Royal Astronomical Society   3 ( 448 )   2704 - 2716   2015.4

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  • An optimal survey geometry of weak lensing survey: minimizing supersample covariance

    Ryuichi Takahashi, Shunji Soma, Masahiro Takada and Issha Kayo

    Monthly Notices of the Royal Astronomical Society   4 ( 444 )   3473 - 3487   2014.11

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  • On the systematic errors of cosmological-scale gravity tests using redshift-space distortion: non-linear effects and the halo bias

    Takashi Ishikawa, Tomonori Totani, Takahiro Nishimichi, Ryuichi Takahashi, Naoki Yoshida and Motonari Tonegawa

    Monthly Notices of the Royal Astronomical Society   4 ( 443 )   3359 - 3367   2014.10

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  • Weak lensing by intergalactic ministructures in quadruple lens systems: simulation and detection

    Ryuichi Takahashi and Kaiki Inoue

    Monthly Notices of the Royal Astronomical Society   1 ( 440 )   870 - 888   2014.5

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  • Bias-hardened CMB lensing with polarization

    Toshiya Namikawa, Ryuichi Takahashi

    Monthly Notices of the Royal Astronomical Society   2 ( 438 )   1507 - 1517   2014.2

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  • Bias-hardened CMB lensing

    Toshiya Namikawa, Duncan Hanson, Ryuichi Takahashi

    Monthly Notices of the Royal Astronomical Society   1 ( 431 )   609 - 620   2013.5

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  • Observational Upper Bound on the Cosmic Abundances of Negative-mass Compact Objects and Ellis Wormholes from the Sloan Digital Sky Survey

    Ryuichi Takahashi, Hideki Asada

    The Astrophysical Journal   1 ( 768 )   L16   2013.5

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  • Revising the Halofit Model for the Nonlinear Matter Power Spectrum

    Ryuichi Takahashi, et al.

    The Astrophysical Journal   2 ( 761 )   152   2012.12

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  • Weak lensing by line-of-sight haloes as the origin of flux-ratio anomalies in quadruply lensed QSOs

    Kaiki Inoue and Ryuichi Takahashi

    Monthly Notices of the Royal Astronomical Society   4 ( 426 )   2978 - 2993   2012.11

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  • Probability Distribution Functions of Cosmological Lensing: Convergence, Shear, and Magnification

    Ryuichi Takahashi, et al.

    The Astrophysical Journal   2 ( 742 )   15   2011.11

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  • Non-Gaussian Error Contribution to Likelihood Analysis of the Matter Power Spectrum

    Ryuichi Takahashi, et al.

    The Astrophysical Journal   1 ( 726 )   7   2011.1

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  • Simulations of Baryon Acoustic Oscillations: Likelihood Analysis of the Matter Power Spectrum

    Ryuichi Takahashi, Naoki Yoshida, Masahiro Takada, Takahiko Matsubara, Naoshi Sugiyama, Issha Kayo, Takahiro Nishimichi, Shun Saito, Atsushi Taruya

    Proceedings of the 19th Workshop on General Relativity and Gravitation in Japan   331 - 334   2010.2

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  • Simulations of Wide-Field Weak Lensing Surveys. I. Basic Statistics and Non-Gaussian Effects

    Masanori Sato, Takashi Hamana, Ryuichi Takahashi, Masahiro Takada, Naoki Yoshida, Takahiko Matsubara, Naoshi Sugiyama

    Astrophysical Journal   701   945 - 954   2009.8

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  • Simulations of Baryon Acoustic Oscillations II: Covariance matrix of the matter power spectrum

    Ryuichi Takahashi, Naoki Yoshida, Masahiro Takada, Takahiko Matsubara, Naoshi Sugiyama, Issha Kayo, Atsushi J. Nishizawa, Takahiro Nishimichi, Shun Saito, Atsushi Taruya

    Astrophysical Journal   700   479 - 490   2009.7

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  • Modeling Nonlinear Evolution of Baryon Acoustic Oscillations: Convergence Regime of N-body Simulations and Analytic Models

    Takahiro Nishimichi, Akihito Shirata, Atsushi Taruya, Kazuhiro Yahata, Shun Saito, Yasushi Suto, Ryuichi Takahashi, Naoki Yoshida, Takahiko Matsubara, Naoshi Sugiyama, Issha Kayo, Yipeng Jing, Kohji Yoshikawa

    Publications of the Astronomical Society of Japan   61   321 - 332   2009.4

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  • Optimal Location of Two Laser-Interferometric Detectors for Gravitational Wave Backgrounds at 100-MHz

    Atsushi Nishizawa, Seiji Kawamura, Tomotada Akutsu, Koji Arai, Kazuhiro Yamamoto, Daisuke Tatsumi, Erina Nishida, Masa-aki Sakagami, Takeshi Chiba, Ryuichi Takahashi, Naoshi Sugiyama

    Classical and Quantum Gravity   25   225011-1 - 225011-14   2008.11

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  • Simulations of Baryon Acoustic Oscillations I : Growth of Large-Scale Density Fluctuations

    Ryuichi Takahashi, Naoki Yoshida, Takahiko Matsubara, Naoshi Sugiyama, Issha Kayo, Takahiro Nishimichi, Akihito Shirata, Atsushi Taruya, Shun Saito, Kazuhiro Yahata, Yasushi Suto

    Monthly Notices of the Royal Astronomical Society   389   1675 - 1682   2008.10

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  • Search for a stochastic background of 100-MHz gravitational waves with laser interferometers.

    Akutsu T, Kawamura S, Nishizawa A, Arai K, Yamamoto K, Tatsumi D, Nagano S, Nishida E, Chiba T, Takahashi R, Sugiyama N, Fukushima M, Yamazaki T, Fujimoto MK

    Physical review letters   101 ( 10 )   101101   2008.9

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    PubMed

  • Search for a stochastic background of 100-MHz gravitational waves with laser interferometers

    Tomotada Akutsu, Seiji Kawamura, Atsushi Nishizawa, Koji Arai, Kazuhiro Yamamoto, Daisuke Tatsumi, Shigeo Nagano, Erina Nishida, Takeshi Chiba, Ryuichi Takahashi, Naoshi Sugiyama, Mitsuhiro Fukushima, Toshitaka Yamazaki, Masa-Katsu Fujimoto

    Physical Review Letters   101   101101-1 - 101101-4   2008.9

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  • Third Order Density Perturbation and One-loop Power Spectrum in a Dark Energy Dominated Universe

    Ryuichi Takahashi

    Progress of Theoretical Physics   120   549 - 559   2008.9

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  • Cosmic Microwave Background Weak Lensing Correlation: Analytical And Numerical Study of Non-linearity and Implications for Dark Energy

    Atsushi J. Nishizawa, Eiichiro Komatsu, Naoki Yoshida, Ryuichi Takahashi, Naoshi Sugiyama

    Astrophysical Journal Letter   676   93 - 96   2008.4

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  • Laser-interferometric Detectors for Gravitational Wave Background at 100 MHz : Detector Design and Sensitivity

    Atsushi Nishizawa, Seiji Kawamura, Tomotada Akutsu, Koji Arai, Kazuhiro Yamamoto, Daisuke Tatsumi, Erina Nishida, Masa-aki Sakagami, Takeshi Chiba, Ryuichi Takahashi, Naoshi Sugiyama

    Phyical Review D   77   022002-1 - 022002-9   2008.1

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  • Weak Lensing of Galaxy Clusters in Modified Newtonian Dynamics

    Ryuichi Takahashi, Takeshi Chiba

    Astrophysical Journal   671   45 - 51   2007.12

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  • A Consistency Relation in Cosmology

    Takeshi Chiba, Ryuichi Takahashi

    Physical Review D   75   101301-1 - 101301-5   2007.5

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  • Lensing Effects on Gravitational Waves in a Clumpy Universe -Effects of Inhomogeneity on the Distance-Redshift Relation-

    Chul-Moon Yoo, Ken-ichi Nakao, Hiroshi Kozaki, Ryuichi Takahashi

    Astrophysical Journal   655   691 - 703   2007.2

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  • Weak Lensing of Galaxy Clusters in Relativistic MOND theory

    Ryuichi Takahashi, Takeshi Chiba

    Proceedings of the 16th Workshop on General Relativity and Gravitation in Japan   219 - 222   2007.1

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  • Amplitude and Phase Fluctuations for Gravitational Waves Propagating Through Inhomogeneous Mass Distribution in the Universe

    Ryuichi Takahashi

    AIP Conference Proceedings   873   120 - 124   2006.12

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  • Amplitude and Phase Fluctuations for Gravitational Waves Propagating through Inhomogeneous Mass Distribution in the Universe

    Ryuichi Takahashi

    Astrophysical Journal   644   80 - 85   2006.6

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  • Exact Wave Propagation in a Spacetime with a Cosmic String

    Teruaki Suyama, Takahiro Tanaka, Ryuichi Takahashi

    Physical Review D   73   024026-1 - 024026-15   2006.1

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  • Classifying The Future of Universes with Dark Energy

    Takeshi Chiba, Ryuichi Takahashi, Naoshi Sugiyama

    Classical and Quantum Gravity   22   3745 - 3758   2005.9

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  • Wave Propagation in a Weak Gravitational Field and The Validity of The Thin Lens Approximation

    Teruaki Suyama, Ryuichi Takahashi, Shugo Michikoshi

    Physical Review D   72   043001-1 - 043001-8   2005.8

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  • Scattering of Gravitational Waves by The Weak Gravitational Fields of Lens Objects

    Ryuichi Takahashi, Teruaki Suyama, Shugo Michikoshi

    Astronomy and Astrophysics Letter   438   5 - 9   2005.7

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Review Papers

  • 宇宙密度揺らぎの振幅問題ー標準宇宙論への警告!?ー

    高橋龍一

    日本物理学会誌   71 ( 5 )   598 - 605   2016.9

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Awards

  • 弘前大学学術特別賞

    2019.12

Social Activities

  • 宇宙の“ダーク”な話

    2018.10.21

  • 弘前中央高校出張講義

    2015.12

  • 講演会「宇宙論研究の最前線」

    2012.03

  • 科学者発見プロジェクト

    2011.08 - 2012.03

  • 弘前大学ドリーム講座

    2011.08

  • 講演会「宇宙論研究の最前線」

    2010.03

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