Persistent X-ray emission from ASASSN-15lh: pre-SLSN dense wind? [HEAP]

http://arxiv.org/abs/1801.07517


The persistent soft X-ray emission at the location of the so-far most luminous supernova (SN), ASASSN-15lh (or SN 2015L), with $L \sim 10^{42} \rm erg~ s^{-1}$, is puzzling. We show that it can be explained by radiation from the SN-shock accelerated electrons inverse-Compton scattering the intense UV photons. In this interpretation, the circumstellar medium is derived to be a wind ($n\propto R^{-2}$) with mass-loss rate of $\dot M \gtrsim 3 \times10^{-3}M_\odot(v_{\rm w}/10^3 \rm km\,s^{-1}) yr^{-1}$, and the initial velocity of the bulk SN ejecta is $\lesssim0.03c$. The non-detection in radio is naturally expected due to strong synchrotron self-absorption and free-free absorption in the dense medium. This constraint implies a strong wind ejected just within $\sim10(v_{\rm w}/10^3 \rm km\,s^{-1})^{-1}$ yrs before the explosion of ASASSN-15lh by its progenitor star.

Read this paper on arXiv…

Y. Huang and Z. Li
Wed, 24 Jan 18
11/73

Comments: 6 pages, 3 figures and 1 table. Comments welcome