Chandra HETG Spectra of SN 1987A at 20 years

TL;DR

This study presents high-resolution X-ray spectra of SN 1987A at 20 years post-explosion, revealing significant changes in plasma temperature and ion velocities over time through detailed spectral analysis.

Contribution

It provides the first high-resolution HETG spectra of SN 1987A at this epoch, showing temporal evolution in plasma temperature and ion kinematics.

Findings

Significant decrease in the highest temperature component from 2004 to 2007.

Lower bulk velocities for Mg and Si ions compared to 2004 observations.

Unprecedented spectral resolution and signal-to-noise in the 6-20 Å bandpass.

Abstract

We have undertaken deep, high-resolution observations of SN 1987A at ~20 years after its explosion with the Chandra HETG and LETG spectrometers. Here we present the HETG X-ray spectra of SN 1987A having unprecedented spectral resolution and signal-to-noise in the 6 A to 20 A bandpass, which includes the H-like and He-like lines of Si, Mg, Ne, as well as O VIII lines and bright Fe XVII lines. In joint analysis with LETG data, we find that there has been a significant decrease from 2004 to 2007 in the average temperature of the highest temperature component of the shocked-plasma emission. Model fitting of the profiles of individual HETG lines yields bulk kinematic velocities of the higher-Z ions, Mg and Si, that are significantly lower than those inferred from the LETG 2004 observations.