skip to content
Home

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

New Probe of Inflationary Gravitational Waves: Cross-Correlations of Lensed Primary CMB B-Modes with Large-Scale Structure.
T Namikawa, BD Sherwin
– Phys Rev Lett
(2023)
131,
131001
(doi: 10.1103/PhysRevLett.131.131001)
Constraints on Early Dark Energy from Isotropic Cosmic Birefringence
JR Eskilt, L Herold, E Komatsu, K Murai, T Namikawa, F Naokawa
– Physical review letters
(2023)
131,
121001
(doi: 10.1103/PhysRevLett.131.121001)
Tensor-to-scalar ratio forecasts for extended LiteBIRD frequency configurations
U Fuskeland, J Aumont, R Aurlien, C Baccigalupi, AJ Banday, HK Eriksen, J Errard, RT Génova-Santos, T Hasebe, J Hubmayr, H Imada, N Krachmalnicoff, L Lamagna, G Pisano, D Poletti, M Remazeilles, KL Thompson, L Vacher, IK Wehus, S Azzoni, M Ballardini, RB Barreiro, N Bartolo, A Basyrov, D Beck, M Bersanelli, M Bortolami, M Brilenkov, E Calabrese, A Carones, FJ Casas, K Cheung, J Chluba, SE Clark, L Clermont, F Columbro, A Coppolecchia, G D'Alessandro, P De Bernardis, T De Haan, E De La Hoz, M De Petris, S Della Torre, P Diego-Palazuelos, F Finelli, C Franceschet, G Galloni, M Galloway, M Gerbino, M Gervasi, T Ghigna, S Giardiello, E Gjerløw, A Gruppuso, P Hargrave, M Hattori, M Hazumi, LT Hergt, D Herman, D Herranz, E Hivon, TD Hoang, K Kohri, M Lattanzi, AT Lee, C Leloup, F Levrier, AI Lonappan, G Luzzi, B Maffei, E Martínez-González, S Masi, S Matarrese, T Matsumura, M Migliaccio, L Montier, G Morgante, B Mot, L Mousset, R Nagata, T Namikawa, F Nati, P Natoli, S Nerval, A Novelli, L Pagano, A Paiella, D Paoletti, G Pascual-Cisneros, G Patanchon, V Pelgrims, F Piacentini, G Piccirilli, G Polenta, G Puglisi, N Raffuzzi, A Ritacco, JA Rubino-Martin, G Savini, D Scott
– Astronomy & Astrophysics
(2023)
676,
a42
(doi: 10.1051/0004-6361/202346155)
Probing early structure and model-independent neutrino mass with high-redshift CMB lensing mass maps
FJ Qu, BD Sherwin, O Darwish, T Namikawa, MS Madhavacheril
– Physical Review D
(2023)
107,
123540
(doi: 10.1103/physrevd.107.123540)
Cosmic birefringence tomography with polarized Sunyaev Zel'dovich effect
T Namikawa, I Obata
(2023)
(link to publication)
BICEP/Keck. XVII. Line-of-sight Distortion Analysis: Estimates of Gravitational Lensing, Anisotropic Cosmic Birefringence, Patchy Reionization, and Systematic Errors
PAR Ade, Z Ahmed, M Amiri, D Barkats, RB Thakur, CA Bischoff, D Beck, JJ Bock, H Boenish, E Bullock, V Buza, JRC Iv, J Connors, J Cornelison, M Crumrine, A Cukierman, EV Denison, M Dierickx, L Duband, M Eiben, S Fatigoni, JP Filippini, S Fliescher, C Giannakopoulos, N Goeckner-Wald, DC Goldfinger, J Grayson, P Grimes, G Hall, G Halal, M Halpern, E Hand, S Harrison, S Henderson, SR Hildebrandt, J Hubmayr, H Hui, KD Irwin, J Kang, KS Karkare, E Karpel, S Kefeli, SA Kernasovskiy, JM Kovac, CL Kuo, K Lau, EM Leitch, A Lennox, KG Megerian, L Minutolo, L Moncelsi, Y Nakato, T Namikawa, HT Nguyen, R O’Brient, RWO Iv, S Palladino, M Petroff, T Prouve, C Pryke, B Racine, CD Reintsema, S Richter, A Schillaci, R Schwarz, BL Schmitt, CD Sheehy, B Singari, A Soliman, TS Germaine, B Steinbach, RV Sudiwala, GP Teply, KL Thompson, JE Tolan, C Tucker, AD Turner, C Umiltà, C Vergès, AG Vieregg, A Wandui, AC Weber, DV Wiebe, J Willmert, CL Wong, WLK Wu, H Yang, KW Yoon, E Young, C Yu, L Zeng, C Zhang, S Zhang
– Astrophysical Journal
(2023)
949,
43
(doi: 10.3847/1538-4357/acc85c)
Plastic Laminate Antireflective Coatings for Millimeter-Wave Optics in BICEP Array
M Dierickx, PAR Ade, Z Ahmed, M Amiri, D Barkats, R Basu Thakur, CA Bischoff, D Beck, JJ Bock, V Buza, J Cheshire, J Connors, J Cornelison, M Crumrine, A Cukierman, E Denison, L Duband, M Eiben, S Fatigoni, JP Filippini, N Goeckner-Wald, DC Goldfinger, JA Grayson, P Grimes, G Hall, G Halal, M Halpern, E Hand, S Harrison, S Henderson, SR Hildebrandt, GC Hilton, J Hubmayr, H Hui, KD Irwin, J Kang, KS Karkare, S Kefeli, JM Kovac, CL Kuo, K Lau, EM Leitch, A Lennox, KG Megerian, L Minutolo, L Moncelsi, Y Nakato, T Namikawa, HT Nguyen, R O’Brient, S Palladino, M Petroff, N Precup, T Prouve, C Pryke, B Racine, CD Reintsema, D Santalucia, A Schillaci, BL Schmitt, B Singari, A Soliman, TS Germaine, B Steinbach, RV Sudiwala, KL Thompson, C Tucker, AD Turner, C Umiltà, C Verges, AG Vieregg, A Wandui, AC Weber, DV Wiebe, J Willmert, WLK Wu, E Yang, KW Yoon, E Young, C Yu, L Zeng, C Zhang, S Zhang
– Journal of Low Temperature Physics
(2023)
211,
366
(doi: 10.1007/s10909-023-02967-1)
Cosmological gravity probes: Connecting recent theoretical developments to forthcoming observations
S Arai, K Aoki, Y Chinone, R Kimura, T Kobayashi, H Miyatake, D Yamauchi, S Yokoyama, K Akitsu, T Hiramatsu, S Hirano, R Kase, T Katsuragawa, Y Kobayashi, T Namikawa, T Nishimichi, T Okumura, M Shiraishi, M Shirasaki, T Sunayama, K Takahashi, A Taruya, J Tokuda
– Progress of Theoretical and Experimental Physics
(2023)
2023,
072e01
(doi: 10.1093/ptep/ptad052)
New probe of inflationary gravitational waves: cross-correlations of lensed primary CMB B-modes with large-scale structure
T Namikawa, BD Sherwin
(2023)
(link to publication)
The reconstructed CMB lensing bispectrum
A Kalaja, G Orlando, A Bowkis, A Challinor, PD Meerburg, T Namikawa
– Journal of Cosmology and Astroparticle Physics
(2023)
2023,
041
(doi: 10.1088/1475-7516/2023/04/041)
  • <
  • 4 of 16
  • >

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