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Relativity and Gravitation Group

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

Bicep2/KECK ARRAY VIII: MEASUREMENT OF GRAVITATIONAL LENSING FROM LARGE-SCALE B-MODE POLARIZATION
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, BP Crill, L Duband, C Dvorkin, JP Filippini, S Fliescher, J Grayson, M Halpern, S Harrison, SR Hildebrandt, GC Hilton, H Hui, KD Irwin, J Kang, KS Karkare, E Karpel, JP Kaufman, BG Keating, S Kefeli, SA Kernasovskiy, JM Kovac, CL Kuo, EM Leitch, M Lueker, KG Megerian, T Namikawa, CB Netterfield, HT Nguyen, R O'Brient, RWO Iv, A Orlando, C Pryke, S Richter, R Schwarz, CD Sheehy, ZK Staniszewski, B Steinbach, RV Sudiwala, GP Teply, KL Thompson, JE Tolan, C Tucker, AD Turner, AG Vieregg, AC Weber, DV Wiebe, J Willmert, CL Wong, WLK Wu, KW Yoon
– Astrophysical Journal
(2016)
833,
228
(doi: 10.3847/1538-4357/833/2/228)
Cosmology with the Square Kilometre Array by SKA-Japan
D Yamauchi, K Ichiki, K Kohri, T Namikawa, Y Oyama, T Sekiguchi, H Shimabukuro, K Takahashi, T Takahashi, S Yokoyama, K Yoshikawa
– Publications of the Astronomical Society of Japan
(2016)
68,
psw098
(doi: 10.1093/pasj/psw098)
Testing statistics of the CMB B-mode polarization toward unambiguously establishing quantum fluctuation of the vacuum
M Shiraishi, C Hikage, R Namba, T Namikawa, M Hazumi
– Physical Review D
(2016)
94,
043506
(doi: 10.1103/PhysRevD.94.043506)
LiteBIRD, Lite satellite for the study of B-mode polarization and Inflation from cosmic microwave background Radiation Detection
H Ishino, Y Akiba, K Arnold, D Barron, J Borrill, R Chendra, Y Chinone, S Cho, A Cukierman, T De Haan, M Dobbs, A Dominjon, T Dotani, T Elleflot, J Errard, T Fujino, H Fuke, T Funaki, N Goeckner-Wald, N Halverson, P Harvey, T Hasebe, M Hasegawa, K Hattori, M Hattori, M Hazumi, N Hidehira, C Hill, G Hilton, W Holzapfel, Y Hori, J Hubmayr, K Ichiki, H Imada, J Inatani, M Inoue, Y Inoue, F Irie, K Irwin, H Ishitsuka, O Jeong, H Kanai, K Karatsu, S Kashima, N Katayama, I Kawano, T Kawasaki, B Keating, S Kernasovskiy, R Keskitalo, A Kibayashi, Y Kida, N Kimura, K Kimura, T Kisner, K Kohri, E Komatsu, K Komatsu, CL Kuo, S Kuromiya, A Kusaka, A Lee, D Li, E Linder, M Maki, H Matsuhara, T Matsumura, S Matsuoka, S Matsuura, S Mima, Y Minami, K Mitsuda, M Nagai, T Nagasaki, R Nagata, M Nakajima, S Nakamura, T Namikawa, M Naruse, T Nishibori, K Nishijo, H Nishino, A Noda, T Noguchi, H Ogawa, W Ogburn, S Oguri, I Ohta, N Okada, A Okamoto, T Okamura, C Otani, G Pisano, G Rebeiz, P Richards, S Sakai, Y Sakurai, Y Sato, N Sato, Y Segawa
– Proceedings of SPIE--the International Society for Optical Engineering
(2016)
9904,
99040X
(doi: 10.1117/12.2231995)
BICEP3 performance overview and planned Keck Array upgrade
JA Grayson, PAR Ade, Z Ahmed, KD Alexander, M Amiri, D Barkats, SJ Benton, CA Bischoff, JJ Bock, H Boenish, R Bowens-Rubin, I Buder, E Bullock, V Buza, J Connors, JP Filippini, S Fliescher, M Halpern, S Harrison, GC Hilton, VV Hristov, H Hui, KD Irwin, J Kang, KS Karkare, E Karpel, S Kefeli, SA Kernasovskiy, JM Kovac, CL Kuo, EM Leitch, M Lueker, KG Megerian, V Monticue, T Namikawa, CB Netterfield, HT Nguyen, R O'Brient, RW Ogburn, C Pryke, CD Reintsema, S Richter, R Schwarz, C Sorenson, CD Sheehy, ZK Staniszewski, B Steinbach, GP Teply, KL Thompson, JE Tolan, C Tucker, AD Turner, AG Vieregg, A Wandui, AC Weber, DV Wiebe, J Willmert, WLK Wu, KW Yoon
– Proceedings of SPIE--the International Society for Optical Engineering
(2016)
9914,
99140s-99140s-17
(doi: 10.1117/12.2233894)
BICEP3 focal plane design and detector performance
H Hui, PAR Ade, Z Ahmed, KD Alexander, M Amiri, D Barkats, SJ Benton, CA Bischoff, JJ Bock, H Boenish, R Bowens-Rubin, I Buder, E Bullock, V Buza, J Connors, JP Filippini, S Fliescher, JA Grayson, M Halpern, S Harrison, GC Hilton, VV Hristov, KD Irwin, J Kang, KS Karkare, E Karpel, S Kefeli, SA Kernasovskiy, JM Kovac, CL Kuo, EM Leitch, M Lueker, KG Megerian, V Monticue, T Namikawa, CB Netterfield, HT Nguyen, R O'Brient, RW Ogburn, C Pryke, CD Reintsema, S Richter, R Schwarz, C Sorensen, CD Sheehy, ZK Staniszewski, B Steinbach, GP Teply, KL Thompson, JE Tolan, C Tucker, AD Turner, AG Vieregg, A Wandui, AC Weber, DV Wiebe, J Willmert, WLK Wu, KW Yoon
– SPIE Proceedings
(2016)
9914,
99140t-99140t-11
(doi: 10.1117/12.2232986)
Optical characterization of the BICEP3 CMB polarimeter at the South Pole
KS Karkare, PAR Ade, Z Ahmed, KD Alexander, M Amiri, D Barkats, SJ Benton, CA Bischoff, JJ Bock, H Boenish, R Bowens-Rubin, I Buder, E Bullock, V Buza, J Connors, JP Filippini, ST Fliescher, JA Grayson, M Halpern, SA Harrison, GC Hilton, VV Hristov, H Hui, KD Irwin, JH Kang, E Karpel, S Kefeli, SA Kernasovskiy, JM Kovac, CL Kuo, EM Leitch, M Lueker, KG Megerian, V Monticue, T Namikawa, CB Netterfield, HT Nguyen, R O'Brient, RW Ogburn, CL Pryke, CD Reintsema, S Richter, MT St Germaine, R Schwarz, CD Sheehy, ZK Staniszewski, B Steinbach, GP Teply, KL Thompson, JE Tolan, C Tucker, AD Turner, AG Vieregg, A Wandui, A Weber, J Willmert, CL Wong, WLK Wu, KW Yoon
– SPIE Proceedings
(2016)
9914,
991430
(doi: 10.1117/12.2231747)
Detecting black-hole binary clustering via the second-generation gravitational-wave detectors
T Namikawa, A Nishizawa, A Taruya
– Physical Review D
(2016)
94,
024013
(doi: 10.1103/physrevd.94.024013)
BICEP2/KECK ARRAY. VII. MATRIX BASED E/B SEPARATION APPLIED TO BICEP2 AND THE KECK ARRAY
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, BP Crill, L Duband, C Dvorkin, JP Filippini, S Fliescher, J Grayson, M Halpern, S Harrison, SR Hildebrandt, GC Hilton, H Hui, KD Irwin, J Kang, KS Karkare, E Karpel, JP Kaufman, BG Keating, S Kefeli, SA Kernasovskiy, JM Kovac, CL Kuo, EM Leitch, M Lueker, KG Megerian, T Namikawa, CB Netterfield, HT Nguyen, R O'Brient, RW Ogburn, A Orlando, C Pryke, S Richter, R Schwarz, CD Sheehy, ZK Staniszewski, B Steinbach, RV Sudiwala, GP Teply, KL Thompson, JE Tolan, C Tucker, AD Turner, AG Vieregg, AC Weber, DV Wiebe, J Willmert, CL Wong, WLK Wu, KW Yoon
– The Astrophysical Journal
(2016)
825,
66
(doi: 10.3847/0004-637x/825/1/66)
CMB lensing bispectrum from nonlinear growth of the large scale structure
T Namikawa
– Physical Review D
(2016)
93,
121301
(doi: 10.1103/physrevd.93.121301)
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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