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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

The Atacama Cosmology Telescope: a measurement of the Cosmic Microwave Background power spectra at 98 and 150 GHz
SK Choi, M Hasselfield, S-PP Ho, B Koopman, M Lungu, MH Abitbol, GE Addison, PAR Ade, S Aiola, D Alonso, M Amiri, S Amodeo, E Angile, JE Austermann, T Baildon, N Battaglia, JA Beall, R Bean, DT Becker, JR Bond, SM Bruno, E Calabrese, V Calafut, LE Campusano, F Carrero, GE Chesmore, H-M Cho, SE Clark, NF Cothard, D Crichton, KT Crowley, O Darwish, R Datta, EV Denison, MJ Devlin, CJ Duell, SM Duff, AJ Duivenvoorden, J Dunkley, R Dünner, T Essinger-Hileman, M Fankhanel, S Ferraro, AE Fox, B Fuzia, PA Gallardo, V Gluscevic, JE Golec, E Grace, M Gralla, Y Guan, K Hall, M Halpern, D Han, P Hargrave, S Henderson, B Hensley, JC Hill, GC Hilton, M Hilton, AD Hincks, R Hložek, J Hubmayr, KM Huffenberger, JP Hughes, L Infante, K Irwin, R Jackson, J Klein, K Knowles, A Kosowsky, V Lakey, D Li, Y Li, Z Li, M Lokken, T Louis, A MacInnis, M Madhavacheril, F Maldonado, M Mallaby-Kay, D Marsden, L Maurin, J McMahon, F Menanteau, K Moodley, T Morton, S Naess, T Namikawa, F Nati, L Newburgh, JP Nibarger, A Nicola, MD Niemack, MR Nolta, J Orlowski-Sherer, LA Page, CG Pappas, B Partridge, P Phakathi, H Prince, R Puddu, FJ Qu, J Rivera, N Robertson, F Rojas, M Salatino, E Schaan, A Schillaci, BL Schmitt, N Sehgal, BD Sherwin, C Sierra, J Sievers, C Sifon, P Sikhosana, S Simon, DN Spergel, ST Staggs, J Stevens, E Storer, DD Sunder, ER Switzer, B Thorne, R Thornton, H Trac, J Treu, C Tucker, LR Vale, AV Engelen, JV Lanen, EM Vavagiakis, K Wagoner, Y Wang, JT Ward, EJ Wollack, Z Xu, F Zago, N Zhu
– Journal of Cosmology and Astroparticle Physics
(2020)
2020,
045
(doi: 10.1088/1475-7516/2020/12/045)
The Atacama Cosmology Telescope: DR4 maps and cosmological parameters
S Aiola, E Calabrese, L Maurin, S Naess, BL Schmitt, MH Abitbol, GE Addison, PAR Ade, D Alonso, M Amiri, S Amodeo, E Angile, JE Austermann, T Baildon, N Battaglia, JA Beall, R Bean, DT Becker, J Richard Bond, SM Bruno, V Calafut, LE Campusano, F Carrero, GE Chesmore, HM Cho, SK Choi, SE Clark, NF Cothard, D Crichton, KT Crowley, O Darwish, R Datta, EV Denison, MJ Devlin, CJ Duell, SM Duff, AJ Duivenvoorden, J Dunkley, R Dünner, T Essinger-Hileman, M Fankhanel, S Ferraro, AE Fox, B Fuzia, PA Gallardo, V Gluscevic, JE Golec, E Grace, M Gralla, Y Guan, K Hall, M Halpern, D Han, P Hargrave, M Hasselfield, JM Helton, S Henderson, B Hensley, J Colin Hill, GC Hilton, M Hilton, AD Hincks, R Hložek, SPP Ho, J Hubmayr, KM Huffenberger, JP Hughes, L Infante, K Irwin, R Jackson, J Klein, K Knowles, B Koopman, A Kosowsky, V Lakey, D Li, Y Li, Z Li, M Lokken, T Louis, M Lungu, A MacInnis, M Madhavacheril, F Maldonado, M Mallaby-Kay, D Marsden, J McMahon, F Menanteau, K Moodley, T Morton, T Namikawa, F Nati, L Newburgh, JP Nibarger, A Nicola, MD Niemack, MR Nolta, J Orlowski-Sherer, LA Page, CG Pappas
– Journal of Cosmology and Astroparticle Physics
(2020)
2020,
047
(doi: 10.1088/1475-7516/2020/12/047)
The Atacama Cosmology Telescope: a CMB lensing mass map over 2100 square degrees of sky and its cross-correlation with BOSS-CMASS galaxies
O Darwish, MS Madhavacheril, BD Sherwin, S Aiola, N Battaglia, JA Beall, DT Becker, JR Bond, E Calabrese, SK Choi, MJ Devlin, J Dunkley, R Dünner, S Ferraro, AE Fox, PA Gallardo, Y Guan, M Halpern, D Han, M Hasselfield, JC Hill, GC Hilton, M Hilton, AD Hincks, SP Patty Ho, J Hubmayr, JP Hughes, BJ Koopman, A Kosowsky, J Van Lanen, T Louis, M Lungu, A MacInnis, L Maurin, J McMahon, K Moodley, S Naess, T Namikawa, F Nati, L Newburgh, JP Nibarger, MD Niemack, LA Page, B Partridge, FJ Qu, N Robertson, A Schillaci, B Schmitt, N Sehgal, C Sifón, DN Spergel, S Staggs, E Storer, A Van Engelen, EJ Wollack
– Monthly Notices of the Royal Astronomical Society
(2020)
500,
2250
(doi: 10.1093/mnras/staa3438)
The Atacama Cosmology Telescope: Weighing Distant Clusters with the Most Ancient Light
MS Madhavacheril, C Sifón, N Battaglia, S Aiola, S Amodeo, JE Austermann, JA Beall, DT Becker, J Richard Bond, E Calabrese, SK Choi, EV Denison, MJ Devlin, SR Dicker, SM Duff, AJ Duivenvoorden, J Dunkley, R Dünner, S Ferraro, PA Gallardo, Y Guan, D Han, J Colin Hill, GC Hilton, M Hilton, J Hubmayr, KM Huffenberger, JP Hughes, BJ Koopman, A Kosowsky, J van Lanen, E Lee, T Louis, A MacInnis, J McMahon, K Moodley, S Naess, T Namikawa, F Nati, L Newburgh, MD Niemack, LA Page, B Partridge, FJ Qu, NC Robertson, M Salatino, E Schaan, A Schillaci, BL Schmitt, N Sehgal, BD Sherwin, SM Simon, DN Spergel, S Staggs, ER Storer, JN Ullom, LR Vale, A van Engelen, EM Vavagiakis, EJ Wollack, Z Xu
– Astrophysical Journal Letters
(2020)
903,
l13
(doi: 10.3847/2041-8213/abbccb)
Weak lensing skew-spectrum
D Munshi, T Namikawa, TD Kitching, JD McEwen, FR Bouchet
– Monthly Notices of the Royal Astronomical Society
(2020)
498,
6057
(doi: 10.1093/mnras/staa2769)
Fitting the Nonlinear Matter Bispectrum by the Halofit Approach
R Takahashi, T Nishimichi, T Namikawa, A Taruya, I Kayo, K Osato, Y Kobayashi, M Shirasaki
– The Astrophysical Journal
(2020)
895,
113
(doi: 10.3847/1538-4357/ab908d)
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 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)
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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