X-ray gamma-ray polarimetry small satellite PolariS

Abstract

PolariS (Polarimetry Satellite) is a Japanese small satellite mission dedicated to polarimetry of X-ray and γ-ray sources. The primary aim of the mission is to perform hard X-ray (10-80 keV) polarimetry of sources brighter than 10 mCrab. For this purpose, PolariS employs three hard X-ray telescopes and scattering type imaging polarimeters. PolariS will measure the X-ray polarization for tens of sources including extragalactic ones mostly for the first time. The second purpose of the mission is γ-ray polarimetry of transient sources, such as γ-ray bursts (GRBs). Wide field polarimeters based on similar concept as that used in the IKAROS/GAP but with higher sensitivity will be used, and polarization measurement of 10 GRBs per year is expected.

Gamma-Ray Polarimetry

“…Due to the large uncertainties in the measurements, any firm conclusion on the hard X-ray origin of the flares was not feasible from these measurements. (Bogomolov et al, 2003), MEGA (Bloser et al, 2006), PHENEX (Gunji et al, 2008), TIGRE (Bhattacharya et al, 2004;O'Neill et al, 1996), PENGUIN-M (Dergachev et al, 2009), GAP (Yonetoku et al, 2006), GRAPE (Bloser et al, 2009), POGO+ (Friis et al, 2018), COSI (Balloon) (Yang et al, 2018), SGD (Aharonian et al, 2018), X-Calibur (Kislat et al, 2018), XL-Calibur (Abarr et al, 2021), IBIS (Ubertini et al, 2003), SPI (Vedrenne et al, 2003), AstroSat (Vadawale et al, 2015), POLAR (Produit et al, 2018), POLAR-2 (Kole, 2019), PING-P (Kotov et al, 2016), PolariS (Hayashida et al, 2014), COSI (SMEX) (Tomsick et al, 2019), LEAP (McConnell et al, 2021), AMEGO (McEnery et al, 2019), e-ASTROGAM (De Angelis et al, 2018) 3 Scattering Polarimetry…”

“…The first flown focal-plane scattering polarimeter was the balloon-borne mission X-Calibur (Beilicke et al, 2014;Guo et al, 2013;Kislat et al, 2018), which will be succeeded by an improved version called XL-Calibur to be launched for the first time in 2022 (Abarr et al, 2021). Other implementations of the principle include the Japanese small satellite PolariS (Polarimetry Satellite, Hayashida et al, 2014) and the Compton X-ray Polarimeter (CXPOL, Chattopadhyay et al, 2013Chattopadhyay et al, , 2014aChattopadhyay et al, 2015) currently under consideration for the next Indian astronomy satellite. All of these polarimeters consist of a compact low-Z scattering element surrounded by high-Z photon detectors, but details of the implementation vary.…”

Development of a hard x-ray focal plane compton polarimeter: a compact polarimetric configuration with scintillators and Si photomultipliers

“…Recent studies [30] suggest that change in polarization because of the hard X-ray mirrors is around ∼ 1 % limiting the sensitivity of the polarimeters at the focal plane of such hard X-ray telescopes to ∼ 1 %. There are few other polarimetric mission proposals based on hard X-ray focal plane Compton polarimeters like X-Calibur [2], PolariS [24] and TSUBAME [55]. Among these, our polarimetric configuration closely resembles with the scattering geometry used in X-Calibur [2], which is under active consideration for NASA's next small satellite mission PolSTAR.…”