Feasibility of Observing Gamma-ray Polarization from Cygnus X-1 Using a CubeSat
Résumé
Instruments flown on CubeSats are small. Meaningful applications of CubeSats in astronomical observations rely on the choice of a particular subject that is feasible for CubeSats. Here we report the result of a feasibility study for observing gamma-ray polarization from Cygnus X-1 using a small Compton polarimeter on board a 3U CubeSat. Silicon detectors and cerium bromide scintillators were employed in the instrument models that we discuss in this study. Through Monte Carlo simulations with a Geant4-based MEGAlib package, we found that, with a 10 Ms on-axis, zenith-direction observation in a low-inclination, low-altitude, Earth-orbit radiation background environment, the minimum detectable polarization degree can be down to about 10% in 160–250 keV, 20% in 250–400 keV, and 65% in 400–2000 keV. A 3U CubeSat dedicated to observing Cygnus X-1 can therefore yield useful information on the polarization state of gamma-ray emissions from the brightest persistent X-ray black hole binary in the sky.
Mots clés
Polarimeters
Astronomical instrumentation
Astrophysical black holes
Gamma-ray astronomy
Gamma-ray detectors
Gamma-ray sources
Gamma-ray telescopes
gamma ray: polarization
gamma ray: emission
beam: polarization
black hole: binary
energy: threshold
numerical calculations: Monte Carlo
semiconductor detector
scintillation counter
trigger
cerium
efficiency
orbit
cesium
background
aluminum
multiple scattering
angular distribution
X-ray