The Latest Evolution in the X-ray Remnant of SN 1987A
Abstract
Based on our continuing Chandra observations, we present the latest evolution of the X-ray remnant of SN 1987A. We present updated X-ray light curves and the radial expansion rate of the remnant as of 2018 September. The soft-band (0.5 - 2 keV) X-ray flux remained constant from ~2012 (day ∼ 9500 since the explosion) till ∼ 2017 (day ∼ 11000), but showed signs of decrease (by ∼ 15%) in September 2018 (at day ∼ 11500). The hard band X-ray flux continues to increase monotonically. While the X-ray remnant has been expanding at a similar rate (v ∼ 1600 km/s) to that reported by Frank et al. (2016) for the last several years, we find indications for an increase in the expansion rate from the data taken in 2018. Continued Chandra observations will be essential to verify (or dispute) these intriguing developments in the light curves and expansion rate of1987A. Based on our new deep (340 ks) Chandra HETG observation(taken in March 2018), we report on some initial results from our high resolution dispersed spectroscopic study of 1987A. Our preliminary analysis shows that the Kα to Ly α line flux ratios for several ions have decreased considerably(e.g., by ∼ 40% for Si and Mg lines) between 2011 and 2018. Our initial results from the spectral model fits to the broadband dispersed spectrum of SN 1987A indicate significant changes in the thermal condition of its X-ray emitting hot gas. We briefly discuss physical implications of these results in terms of 1987A's evolution in the past seven years.
- Publication:
-
Supernova Remnants: An Odyssey in Space after Stellar Death II
- Pub Date:
- June 2019
- Bibcode:
- 2019sros.confE..26R