ORCID Profile
0000-0001-9461-7519
Current Organisation
University of Colorado at Boulder
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Publisher: American Physical Society (APS)
Date: 18-08-2023
Publisher: American Astronomical Society
Date: 20-11-2020
Publisher: American Astronomical Society
Date: 11-08-2015
Publisher: American Astronomical Society
Date: 27-05-2022
Abstract: We report an improved measurement of the degree-scale cosmic microwave background B -mode angular-power spectrum over 670 deg 2 sky area at 150 GHz with P olarbear . In the original analysis of the data, errors in the angle measurement of the continuously rotating half-wave plate, a polarization modulator, caused significant data loss. By introducing an angle-correction algorithm, the data volume is increased by a factor of 1.8. We report a new analysis using the larger data set. We find the measured B -mode spectrum is consistent with the ΛCDM model with Galactic dust foregrounds. We estimate the contamination of the foreground by cross-correlating our data and Planck 143, 217, and 353 GHz measurements, where its spectrum is modeled as a power law in angular scale and a modified blackbody in frequency. We place an upper limit on the tensor-to-scalar ratio r 0.33 at 95% confidence level after marginalizing over the foreground parameters.
Publisher: Springer Science and Business Media LLC
Date: 07-09-2018
Publisher: Springer Science and Business Media LLC
Date: 27-01-2020
DOI: 10.1007/S10909-019-02329-W
Abstract: Recent developments of transition-edge sensors (TESs), based on extensive experience in ground-based experiments, have been making the sensor techniques mature enough for their application on future satellite cosmic microwave background (CMB) polarization experiments. LiteBIRD is in the most advanced phase among such future satellites, targeting its launch in Japanese Fiscal Year 2027 (2027FY) with JAXA’s H3 rocket. It will accommodate more than 4000 TESs in focal planes of reflective low-frequency and refractive medium-and-high-frequency telescopes in order to detect a signature imprinted on the CMB by the primordial gravitational waves predicted in cosmic inflation. The total wide frequency coverage between 34 and 448 GHz enables us to extract such weak spiral polarization patterns through the precise subtraction of our Galaxy’s foreground emission by using spectral differences among CMB and foreground signals. Telescopes are cooled down to 5 K for suppressing thermal noise and contain polarization modulators with transmissive half-wave plates at in idual apertures for separating sky polarization signals from artificial polarization and for mitigating from instrumental 1/ f noise. Passive cooling by using V-grooves supports active cooling with mechanical coolers as well as adiabatic demagnetization refrigerators. Sky observations from the second Sun–Earth Lagrangian point, L2, are planned for 3 years. An international collaboration between Japan, the USA, Canada, and Europe is sharing various roles. In May 2019, the Institute of Space and Astronautical Science, JAXA, selected LiteBIRD as the strategic large mission No. 2.
Publisher: American Astronomical Society
Date: 18-11-2019
Publisher: SPIE
Date: 19-08-2014
DOI: 10.1117/12.2057332
Publisher: American Physical Society (APS)
Date: 09-07-2014
Publisher: American Astronomical Society
Date: 07-2020
Publisher: SPIE
Date: 19-08-2014
DOI: 10.1117/12.2055572
Publisher: American Astronomical Society
Date: 23-10-2017
Publisher: American Physical Society (APS)
Date: 02-04-2014
Publisher: American Physical Society (APS)
Date: 08-12-2015
Publisher: Springer Science and Business Media LLC
Date: 06-01-2016
Publisher: American Astronomical Society
Date: 04-09-2019
Publisher: American Astronomical Society
Date: 14-01-2019
No related grants have been discovered for Satoru Takakura.