Progress Report on the Large-Scale Polarization Explorer
- PDF / 1,134,312 Bytes
- 10 Pages / 439.37 x 666.142 pts Page_size
- 47 Downloads / 182 Views
Progress Report on the Large‑Scale Polarization Explorer L. Lamagna, et al. [full author details at the end of the article] Received: 5 August 2019 / Accepted: 21 March 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract The large-scale polarization explorer (LSPE) is a cosmology program for the measurement of large-scale curl-like features (B-modes) in the polarization of the cosmic microwave background. Its goal is to constrain the background of inflationary gravity waves traveling through the universe at the time of matter-radiation decoupling. The two instruments of LSPE are meant to synergically operate by covering a large portion of the northern microwave sky. LSPE/STRIP is a coherent array of receivers planned to be operated from the Teide Observatory in Tenerife, for the control and characterization of the low-frequency polarized signals of galactic origin; LSPE/ SWIPE is a balloon-borne bolometric polarimeter based on 330 large throughput multi-moded detectors, designed to measure the CMB polarization at 150 GHz and to monitor the polarized emission by galactic dust above 200 GHz. The combined performance and the expected level of systematics mitigation will allow LSPE to constrain primordial B-modes down to a tensor/scalar ratio of 10−2 . We here report the status of the STRIP pre-commissioning phase and the progress in the characterization of the key subsystems of the SWIPE payload (namely the cryogenic polarization modulation unit and the multi-moded TES pixels) prior to receiver integration. Keywords Cosmic microwave background · B-modes · Transition edge sensors · Multi-moded optics
1 Introduction Measurements of the cosmic microwave background (CMB) polarization anisotropies offer strong probes of the standard cosmological model. Linear polarization of the CMB is known to emerge from Thomson scattering off electrons at the last scattering surface in the presence of local quadrupole anisotropies in the scattered radiation field. The polarization pattern observed in the sky is commonly decomposed in a curl-free “E-mode” and a divergence-free “B-mode.” E-modes alone emerge in the presence of the velocity fields around peaks in the baryon-photon fluid at last scattering and thus exhibit a tight correlation with the temperature anisotropies of the CMB. As such, the TE angular cross-power spectrum and the EE power spectrum can be usefully combined with the TT power spectrum to break degeneracies among cosmological parameters, and to constrain specific parameters (e.g. the reionization
13
Vol.:(0123456789)
Journal of Low Temperature Physics
optical depth) otherwise loosely constrained by temperature anisotropies. On the other hand, B-modes at small angular scales are observed as a result of E-to-B leakage due to gravitational lensing, and as such observed in correlation to the line-ofsight integrated lensing potential due to the presence of large-scale structure across the light path to last scattering surface. In addition, a large (degree and above) scale contributi
Data Loading...
