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Department of Applied Mathematics and Theoretical Physics

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

Internal Delensing of Cosmic Microwave Background Polarization B-Modes with the POLARBEAR Experiment
S Adachi, MAO Aguilar Faúndez, Y Akiba, A Ali, K Arnold, C Baccigalupi, D Barron, D Beck, F Bianchini, J Borrill, J Carron, K Cheung, Y Chinone, K Crowley, H El Bouhargani, T Elleflot, J Errard, G Fabbian, C Feng, T Fujino, N Goeckner-Wald, M Hasegawa, M Hazumi, CA Hill, L Howe, N Katayama, B Keating, S Kikuchi, A Kusaka, AT Lee, D Leon, E Linder, LN Lowry, F Matsuda, T Matsumura, Y Minami, T Namikawa, M Navaroli, H Nishino, J Peloton, ATP Pham, D Poletti, G Puglisi, CL Reichardt, Y Segawa, BD Sherwin, M Silva-Feaver, P Siritanasak, R Stompor, O Tajima, S Takatori, D Tanabe, GP Teply, C Vergès, POLARBEAR Collaboration
– Physical review letters
(2020)
124,
131301
(doi: 10.1103/PhysRevLett.124.131301)
CMB-HD: Astro2020 RFI Response
N Sehgal, S Aiola, Y Akrami, KM Basu, M Boylan-Kolchin, S Bryan, CM Casey, S Clesse, F-Y Cyr-Racine, LD Mascolo, S Dicker, T Essinger-Hileman, S Ferraro, G Fuller, N Galitzki, D Han, M Hasselfield, G Holder, B Jain, BR Johnson, M Johnson, P Klaassen, A MacInnis, M Madhavacheril, P Mauskopf, D Meerburg, J Meyers, T Mroczkowski, S Mukherjee, M Münchmeyer, SK Naess, D Nagai, T Namikawa, L Newburgh, N Nguyen, M Niemack, BD Oppenheimer, E Pierpaoli, E Schaan, B Sherwin, A Slosar, D Spergel, E Switzer, P Trivedi, Y-D Tsai, AV Engelen, B Wandelt, E Wollack
(2020)
(link to publication)
Characterizing the Sensitivity of 40 GHz TES Bolometers for BICEP Array
C Zhang, PAR Ade, Z Ahmed, M Amiri, D Barkats, RB Thakur, CA Bischoff, JJ Bock, H Boenish, E Bullock, V Buza, J Cheshire, J Connors, J Cornelison, M Crumrine, A Cukierman, M Dierickx, L Duband, S Fatigoni, JP Filippini, G Hall, M Halpern, S Harrison, S Henderson, SR Hildebrandt, GC Hilton, H Hui, KD Irwin, J Kang, KS Karkare, E Karpel, S Kefeli, JM Kovac, CL Kuo, K Lau, KG Megerian, L Moncelsi, T Namikawa, HT Nguyen, R O’Brient, S Palladino, N Precup, T Prouvé, C Pryke, B Racine, CD Reintsema, S Richter, A Schillaci, B Schmitt, R Schwarz, CD Sheehy, A Soliman, TS Germaine, B Steinbach, RV Sudiwala, KL Thompson, C Tucker, AD Turner, C Umiltà, AG Vieregg, A Wandui, AC Weber, DV Wiebe, J Willmert, WLK Wu, E Yang, KW Yoon, E Young, C Yu
– Journal of Low Temperature Physics
(2020)
199,
968
(doi: 10.1007/s10909-020-02411-8)
Optical Characterization of the Keck Array and BICEP3 CMB Polarimeters from 2016 to 2019
TBICEPK Collaboration, TS Germaine, PAR Ade, Z Ahmed, M Amiri, D Barkats, RB Thakur, CA Bischoff, JJ Bock, H Boenish, E Bullock, V Buza, J Cheshire, J Connors, J Cornelison, M Crumrine, A Cukierman, M Dierickx, L Duband, S Fatigoni, JP Filippini, S Fliescher, JA Grayson, G Hall, M Halpern, S Harrison, SR Hildebrandt, GC Hilton, H Hui, KD Irwin, J Kang, KS Karkare, E Karpel, S Kefeli, SA Kernasovskiy, JM Kovac, CL Kuo, K Lau, EM Leitch, KG Megerian, L Moncelsi, T Namikawa, CB Netterfield, HT Nguyen, R O'Brient, RWO IV, S Palladino, C Pryke, B Racine, CD Reintsema, S Richter, A Schillaci, R Schwarz, CD Sheehy, A Soliman, B Steinbach, RV Sudiwala, KL Thompson, JE Tolan, C Tucker, AD Turner, C Umilta, AG Vieregg, A Wandui, AC Weber, DV Wiebe, J Willmert, CL Wong, WLK Wu, E Yang, KW Yoon, E Young, C Yu, C Zhang
– Journal of Low Temperature Physics
(2020)
199,
824
(doi: 10.1007/s10909-020-02392-8)
Optical Design and Characterization of 40-GHz Detector and Module for the BICEP Array
A Soliman, PAR Ade, Z Ahmed, M Amiri, D Barkats, RB Thakur, CA Bischoff, JJ Bock, H Boenish, E Bullock, V Buza, J Cheshire, J Connors, J Cornelison, M Crumrine, A Cukierman, M Dierickx, L Duband, S Fatigoni, JP Filippini, G Hall, M Halpern, S Harrison, S Henderson, SR Hildebrandt, GC Hilton, H Hui, KD Irwin, J Kang, KS Karkare, E Karpel, S Kefeli, JM Kovac, CL Kuo, K Lau, KG Megerian, L Moncelsi, T Namikawa, HT Nguyen, R O’Brient, S Palladino, T Prouve, N Precup, C Pryke, B Racine, CD Reintsema, S Richter, B Schmitt, R Schwarz, CD Sheehy, A Schillaci, TS Germaine, B Steinbach, RV Sudiwala, KL Thompson, C Tucker, AD Turner, C Umiltà, AG Vieregg, A Wandui, AC Weber, DV Wiebe, J Willmert, WLK Wu, E Yang, KW Yoon, E Young, C Yu, C Zhang
– Journal of Low Temperature Physics
(2020)
199,
1118
(doi: 10.1007/s10909-019-02299-z)
The weak lensing bispectrum induced by gravity
D Munshi, T Namikawa, TD Kitching, JD McEwen, R Takahashi, FR Bouchet, A Taruya, B Bose
– Monthly Notices of the Royal Astronomical Society
(2020)
493,
3985
(doi: 10.1093/mnras/staa296)
Design and Performance of the First BICEP Array Receiver
A Schillaci, PAR Ade, Z Ahmed, M Amiri, D Barkats, RB Thakur, CA Bischoff, JJ Bock, H Boenish, E Bullock, V Buza, J Cheshire, J Connors, J Cornelison, M Crumrine, A Cukierman, M Dierickx, L Duband, S Fatigoni, JP Filippini, G Hall, M Halpern, S Harrison, S Henderson, SR Hildebrandt, GC Hilton, H Hui, KD Irwin, J Kang, KS Karkare, E Karpel, S Kefeli, JM Kovac, CL Kuo, K Lau, KG Megerian, L Moncelsi, T Namikawa, HT Nguyen, R O’Brient, S Palladino, N Precup, T Prouve, C Pryke, B Racine, CD Reintsema, S Richter, BL Schmitt, R Schwarz, CD Sheehy, A Soliman, TS Germaine, B Steinbach, RV Sudiwala, KL Thompson, C Tucker, AD Turner, C Umiltà, AG Vieregg, A Wandui, AC Weber, DV Wiebe, J Willmert, WLK Wu, E Yang, KW Yoon, E Young, C Yu, C Zhang
– Journal of Low Temperature Physics
(2020)
199,
976
(doi: 10.1007/s10909-020-02394-6)
Updated Design of the CMB Polarization Experiment Satellite LiteBIRD
H Sugai, PAR Ade, Y Akiba, D Alonso, K Arnold, J Aumont, J Austermann, C Baccigalupi, AJ Banday, R Banerji, RB Barreiro, S Basak, J Beall, S Beckman, M Bersanelli, J Borrill, F Boulanger, ML Brown, M Bucher, A Buzzelli, E Calabrese, FJ Casas, A Challinor, V Chan, Y Chinone, JF Cliche, F Columbro, A Cukierman, D Curtis, P Danto, P de Bernardis, T de Haan, M De Petris, C Dickinson, M Dobbs, T Dotani, L Duband, A Ducout, S Duff, A Duivenvoorden, JM Duval, K Ebisawa, T Elleflot, H Enokida, HK Eriksen, J Errard, T Essinger-Hileman, F Finelli, R Flauger, C Franceschet, U Fuskeland, K Ganga, JR Gao, R Génova-Santos, T Ghigna, A Gomez, ML Gradziel, J Grain, F Grupp, A Gruppuso, JE Gudmundsson, NW Halverson, P Hargrave, T Hasebe, M Hasegawa, M Hattori, M Hazumi, S Henrot-Versille, D Herranz, C Hill, G Hilton, Y Hirota, E Hivon, R Hlozek, DT Hoang, J Hubmayr, K Ichiki, T Iida, H Imada, K Ishimura, H Ishino, GC Jaehnig, M Jones, T Kaga, S Kashima, Y Kataoka, N Katayama, T Kawasaki, R Keskitalo, A Kibayashi, T Kikuchi, K Kimura, T Kisner, Y Kobayashi, N Kogiso, A Kogut, K Kohri, E Komatsu, K Komatsu, K Konishi
– Journal of Low Temperature Physics
(2020)
199,
1107
(doi: 10.1007/s10909-019-02329-w)
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, M Brown, M Bucher, E Calabrese, P Campeti, A Carones, FJ Casas, A Challinor, V Chan, K Cheung, Y Chinone, JF Cliche, L Colombo, F Columbro, J Cubas, A Cukierman, D Curtis, G D'alessandro, N Dachlythra, M De Petris, C Dickinson, P Diego-Palazuelos, M Dobbs, T Dotani, L Duband, S Duff, JM Duval, K Ebisawa, T Elleflot, HK Eriksen, J Errard, T Essinger-Hileman, F Finelli, R Flauger, C Franceschet, U Fuskeland, M Galloway, K Ganga, JR Gao, R Genova-Santos, M Gerbino, M Gervasi, T Ghigna, E Gjerløw, ML Gradziel, J Grain, F Grupp, A Gruppuso, JE Gudmundsson, T De Haan, NW Halverson, P Hargrave, T Hasebe, M Hasegawa, M Hattori, S Henrot-Versillé, D Herman, D Herranz, CA Hill, G Hilton, Y Hirota, E Hivon, RA Hlozek, Y Hoshino, E De La Hoz, J Hubmayr, K Ichiki, T Iida, H Imada, K Ishimura, H Ishino, G Jaehnig, T Kaga, S Kashima, N Katayama, A Kato
– Proceedings of SPIE the International Society for Optical Engineering
(2020)
11443,
114432f-114432f-20
(doi: 10.1117/12.2563050)
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, M Brown, M Bucher, E Calabrese, P Campeti, A Carones, FJ Casas, A Challinor, V Chan, K Cheung, Y Chinone, JF Cliche, L Colombo, F Columbro, J Cubas, A Cukierman, D Curtis, G D'Alessandro, N Dachlythra, M De Petris, C Dickinson, P Diego-Palazuelos, M Dobbs, T Dotani, L Duband, S Duff, JM Duval, K Ebisawa, T Elleflot, HK Eriksen, J Errard, T Essinger-Hileman, F Finelli, R Flauger, C Franceschet, U Fuskeland, M Galloway, K Ganga, JR Gao, R Genova-Santos, M Gerbino, M Gervasi, T Ghigna, E Gjerløw, ML Gradziel, J Grain, F Grupp, A Gruppuso, JE Gudmundsson, T De Haan, NW Halverson, P Hargrave, T Hasebe, M Hasegawa, M Hattori, M Hazumi, S Henrot-Versille, D Herman, D Herranz, CA Hill, G Hilton, Y Hirota, E Hivon, RA Hlozek, Y Hoshino, E De La Hoz, J Hubmayr, K Ichiki, T Iida, H Imada, K Ishimura, H Ishino, G Jaehnig, T Kaga, S Kashima, N Katayama
– Proceedings of SPIE the International Society for Optical Engineering
(2020)
11453,
37
(doi: 10.1117/12.2561841)
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Research Group

Relativity and Gravitation

Email

tn334@damtp.cam.ac.uk

Room

B1.09

Telephone

01223 337843

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