Chandra observations of SN 1987A: the soft X-ray light curve revisited

TL;DR

This paper revisits the soft X-ray light curve of SN 1987A using updated Chandra data, revealing a continuous increase in flux and ongoing shock interaction with the equatorial ring.

Contribution

It provides a revised analysis of SN 1987A's X-ray evolution with new data and calibration, challenging previous findings of flux flattening in 2009.

Findings

0.5-2.0 keV fluxes increased since 2009

Forward shock still interacting with equatorial ring

Calibration issues significantly affect flux measurements

Abstract

We report on the present stage of SN 1987A as observed by the Chandra X-ray Observatory. We reanalyze published Chandra observations and add three more epochs of Chandra data to get a consistent picture of the evolution of the X-ray fluxes in several energy bands. We discuss the implications of several calibration issues for Chandra data. Using the most recent Chandra calibration files, we find that the 0.5-2.0 keV band fluxes of SN 1987A have increased by ~6 x 10 ^-13 erg s^-1 cm^-2 per year since 2009. This is in contrast with our previous result that the 0.5-2.0 keV light curve showed a sudden flattening in 2009. Based on our new analysis, we conclude that the forward shock is still in full interaction with the equatorial ring.