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Faculty of Mathematics

 

Dr Toshiya Namikawa

Career

  • 2019 - Now : Senior Research Associate, DAMTP, University of Cambridge
  • 2018 - 2018: Assistant Researcher (termed Assistant Professor), National Taiwan Univeristy
  • 2014 - 2017: Postdoctoral Researcher (with JSPS fellowship for two years), KIPAC, Stanford University
  • 2013 - 2014: Postdoctoral Researcher, Yukawa Institute for Theoretical Physics, Kyoto University
  • 2010 - 2013: PhD Student, University of Tokyo
  • 2008 - 2010: Master Student, University of Tokyo

Research

Toshiya is a member of the Department of Applied Mathematics and Theoretical Physics, in the Relativity and Gravitation research group. He is working on data-driven cosmology, the intersection between theoretical and observational cosmology. His current interests include B-mode analysis, gravitational lensing of CMB, cosmic birefringence, reionization and non-Gaussianity. He is an active member of several CMB experiments. 

 

Selected Publications

  • T. Namikawa et al. (ACTPol Collaboration), "The Atacama Cosmology Telescope: Constraints on Cosmic Birefringence", Phys. Rev. D, 101, 10465, 2020, arXiv:2001.10465
  • T. Namikawa et al. (POLARBEAR and Subaru-HSC Collaborations), "Evidence for the Cross-correlation between Cosmic Microwave Background Polarization Lensing from POLARBEAR and Cosmic Shear from Subaru Hyper Suprime-Cam", Astrophys. J., 882, 12, 2019, arXiv:1904.02116
  • BICEP2/Keck Array Collaborations, "BICEP2 / Keck Array X: Improved Constraints on Inflationary Gravitational Waves using BICEP2/Keck Data up to the 2015 Season in Conjunction with WMAP/Planck", Phys. Rev. Lett., 121, 221301, 2018, arXiv:1810.05216
  • T. Namikawa, "CMB internal delensing with general optimal estimator for higher-order correlations", Phys. Rev. D, 95, 103514, 2017, arXiv:1703.00169
  • BICEP2/Keck Array Collaborations, "BICEP2 / Keck Array IX: New Bounds on Anisotropies of CMB Polarization Rotation and Implications for Axion-Like Particles and Primordial Magnetic Fields", Phys. Rev. D, 96, 102003, 2017, arXiv:1705.02523
  • BICEP2/Keck Array Collaborations, "BICEP2 / Keck Array VIII: Measurement of Gravitational Lensing from Large-Scale B-mode Polarization", Astrophys. J., 833, 228, 2016, arXiv:1606.01968
  • T. Namikawa, "CMB Lensing bispectrum from Nonlinear Growth of the Large Scale Structure", Phys. Rev. D Rapid Communications, 93, 121301, 2016, arXiv:1604.08578
  • T. Namikawa et al., "Anisotropies of gravitational-wave standard sirens as a new cosmological probe without redshift information", Phys. Rev. Lett., 116, 0121302, 2016, arXiv:1511.04638
  • T. Namikawa et al.. "Bias-Hardened CMB Lensing", Mon. Not. R. Astron. Soc., 431, 609, 2013, arXiv:1209.0091
  • T. Namikawa et al., "Full-sky lensing reconstruction of gradient and curl modes from CMB maps", J. Cosmol. Astropart. Phys., 01, 007, 2012, arXiv:1110.1718

Publications

CMB-S4 Decadal Survey APC White Paper
K Abazajian, G Addison, P Adshead, Z Ahmed, SW Allen, D Alonso, M Alvarez, MA Amin, A Anderson, KS Arnold, C Baccigalupi, K Bailey, D Barkats, D Barron, PS Barry, JG Bartlett, RB Thakur, N Battaglia, E Baxter, R Bean, C Bebek, AN Bender, BA Benson, E Berger, S Bhimani et al.
(2019)
(doi: 10.2172/1556957)
CMB constraints on the stochastic gravitational-wave background at Mpc scales
T Namikawa, S Saga, D Yamauchi, A Taruya
– Physical Review D
(2019)
100,
021303
(doi: 10.1103/PhysRevD.100.021303)
The Simons Observatory: Astro2020 Decadal Project Whitepaper
TSO Collaboration, MH Abitbol, S Adachi, P Ade, J Aguirre, Z Ahmed, S Aiola, A Ali, D Alonso, MA Alvarez, K Arnold, P Ashton, Z Atkins, J Austermann, H Awan, C Baccigalupi, T Baildon, AB Lizancos, D Barron, N Battaglia, R Battye, E Baxter, A Bazarko, JA Beall, R Bean et al.
– Bull. Am. Astron. Soc.
(2019)
51,
147
(link to publication)
CMB-S4 Science Case, Reference Design, and Project Plan
K Abazajian, G Addison, P Adshead, Z Ahmed, SW Allen, D Alonso, M Alvarez, A Anderson, KS Arnold, C Baccigalupi, K Bailey, D Barkats, D Barron, PS Barry, JG Bartlett, RB Thakur, N Battaglia, E Baxter, R Bean, C Bebek, AN Bender, BA Benson, E Berger, S Bhimani, CA Bischoff et al.
(2019)
(link to publication)
CMB-HD: An Ultra-Deep, High-Resolution Millimeter-Wave Survey Over Half the Sky
N Sehgal, S Aiola, Y Akrami, K Basu, M Boylan-Kolchin, S Bryan, S Clesse, F-Y Cyr-Racine, LD Mascolo, S Dicker, T Essinger-Hileman, S Ferraro, GM Fuller, D Han, M Hasselfield, G Holder, B Jain, B Johnson, M Johnson, P Klaassen, M Madhavacheril, P Mauskopf, D Meerburg, J Meyers, T Mroczkowski et al.
– Bulletin of the American Astronomical Society, Vol. 51, Issue 7, id. 6 (2019)
(2019)
(link to publication)
CMB lensing bispectrum: Assessing analytical predictions against full-sky lensing simulations
T Namikawa, B Bose, FR Bouchet, R Takahashi, A Taruya
– Physical Review D
(2019)
99,
063511
(doi: 10.1103/PhysRevD.99.063511)
LiteBIRD: A Satellite for the Studies of B-Mode Polarization and Inflation from Cosmic Background Radiation Detection
M Hazumi, PAR Ade, Y Akiba, D Alonso, K Arnold, J Aumont, C Baccigalupi, D Barron, S Basak, S Beckman, J Borrill, F Boulanger, M Bucher, E Calabrese, Y Chinone, S Cho, A Cukierman, DW Curtis, T de Haan, M Dobbs, A Dominjon, T Dotani, L Duband, A Ducout, J Dunkley et al.
– Journal of Low Temperature Physics
(2019)
194,
443
(doi: 10.1007/s10909-019-02150-5)
Impact of nonlinear growth of the large-scale structure on CMB B-mode delensing
T Namikawa, R Takahashi
– Physical Review D
(2019)
99,
023530
(doi: 10.1103/PhysRevD.99.023530)
Effect of non-Gaussian lensing deflections on CMB lensing measurements
V Böhm, BD Sherwin, J Liu, JC Hill, M Schmittfull, T Namikawa
– Physical Review D
(2018)
98,
123510
(doi: 10.1103/physrevd.98.123510)
Constraints on Primordial Gravitational Waves Using Planck, WMAP, and New BICEP2/ Keck Observations through the 2015 Season
PAR Ade, Z Ahmed, RW Aikin, KD Alexander, D Barkats, SJ Benton, CA Bischoff, JJ Bock, R Bowens-Rubin, JA Brevik, I Buder, E Bullock, V Buza, J Connors, J Cornelison, BP Crill, M Crumrine, M Dierickx, L Duband, C Dvorkin, JP Filippini, S Fliescher, J Grayson, G Hall, M Halpern et al.
– Phys Rev Lett
(2018)
121,
221301
(doi: 10.1103/physrevlett.121.221301)
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Research Group

Relativity and Gravitation

Email

tn334@damtp.cam.ac.uk

Room

B1.09

Telephone

01223 337843

Study at Cambridge

About the University

Research at Cambridge