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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

Receiver development for BICEP Array, a next-generation CMB polarimeter at the South Pole
L Moncelsi, PAR Ade, Z Ahmed, M Amiri, D Barkats, R Basu Thakur, CA Bischoff, JJ Bock, V Buza, JR Cheshire, J Connors, J Cornelison, M Crumrine, AJ Cukierman, EV Denison, M Dierickx, L Duband, M Eiben, S Fatigoni, JP Filippini, N Goeckner-Wald, D Goldfinger, JA Grayson, P Grimes, G Hall et al.
– Proceedings of SPIE the International Society for Optical Engineering
(2020)
11453,
41
(doi: 10.1117/12.2561995)
LiteBIRD satellite: JAXA's new strategic L-class mission for all-sky surveys of cosmic microwave background polarization
M Hazumi, PAR Ade, A Adler, E Allys, K Arnold, D Auguste, J Aumont, R Aurlien, J Austermann, C Baccigalupi, AJ Banday, R Banjeri, RB Barreiro, S Basak, J Beall, D Beck, S Beckman, J Bermejo, P De Bernardis, M Bersanelli, J Bonis, J Borrill, F Boulanger, S Bounissou, M Brilenkov et al.
– Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave
(2020)
11443,
114432f-114432f-20
(doi: 10.1117/12.2563050)
Overview of the Medium and High Frequency Telescopes of the LiteBIRD satellite mission
L Montier, B Mot, P De Bernardis, B Maffei, G Pisano, F Columbro, JE Gudmundsson, S Henrot-Versillé, L Lamagna, J Montgomery, T Prouvé, M Russell, G Savini, S Stever, KL Thompson, M Tsujimoto, C Tucker, B Westbrook, PAR Ade, A Adler, E Allys, K Arnold, D Auguste, J Aumont, R Aurlien et al.
– SPACE TELESCOPES AND INSTRUMENTATION 2020: OPTICAL, INFRARED, AND MILLIMETER WAVE
(2020)
11443,
114432g-114432g-21
(doi: 10.1117/12.2562243)
Concept design of low frequency telescope for CMB B-mode polarization satellite LiteBIRD
Y Sekimoto, PAR Ade, A Adler, E Allys, K Arnold, D Auguste, J Aumont, R Aurlien, J Austermann, C Baccigalupi, AJ Banday, R Banerji, RB Barreiro, S Basak, J Beall, D Beck, S Beckman, J Bermejo, P De Bernardis, M Bersanelli, J Bonis, J Borrill, F Boulanger, S Bounissou, M Brilenkov et al.
– Proceedings of SPIE the International Society for Optical Engineering
(2020)
11453,
37
(doi: 10.1117/12.2561841)
Microwave Multiplexing on the Keck Array
A Cukierman, Z Ahmed, S Henderson, E Young, C Yu, D Barkats, D Brown, S Chaudhuri, J Cornelison, JM D’Ewart, M Dierickx, BJ Dober, J Dusatko, S Fatigoni, JP Filippini, JC Frisch, G Haller, M Halpern, GC Hilton, J Hubmayr, KD Irwin, KS Karkare, E Karpel, SA Kernasovskiy, JM Kovac et al.
– Journal of Low Temperature Physics
(2019)
199,
858
(doi: 10.1007/s10909-019-02296-2)
BICEP2/Keck Array XI: Beam Characterization and Temperature-to-Polarization Leakage in the BK15 Data Set
PAR Ade, Z Ahmed, RW Aikin, 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, JP Filippini, S Fliescher, J Grayson, G Hall, M Halpern, S Harrison, SR Hildebrandt et al.
– The Astrophysical Journal
(2019)
884,
114
(doi: 10.3847/1538-4357/ab391d)
Evidence for the Cross-correlation between Cosmic Microwave Background Polarization Lensing from Polarbear and Cosmic Shear from Subaru Hyper Suprime-Cam
T Namikawa, Y Chinone, H Miyatake, M Oguri, R Takahashi, A Kusaka, N Katayama, S Adachi, M Aguilar, H Aihara, A Ali, R Armstrong, K Arnold, C Baccigalupi, D Barron, D Beck, S Beckman, F Bianchini, D Boettger, J Borrill, K Cheung, L Corbett, KT Crowley, HE Bouhargani, T Elleflot et al.
– Astrophysical Journal
(2019)
882,
62
(doi: 10.3847/1538-4357/ab3424)
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)
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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