Spectral Evolution of the X-Ray Remnant of SN 1987A: A High-Resolution $Chandra$ HETG Study

Abstract

Based on observations with the $Chandra$ X-ray Observatory, we present the latest spectral evolution of the X-ray remnant of SN 1987A (SNR 1987A). We present a high-resolution spectroscopic analysis using our new deep ($\sim$312 ks) $Chandra$ HETG observation taken in March 2018, as well as archival $Chandra$ gratings spectroscopic data taken in 2004, 2007, and 2011 with similarly deep exposures ($\sim$170 - 350 ks). We perform detailed spectral model fits to quantify changing plasma conditions over the last 14 years. Recent changes in electron temperatures and volume emission measures suggest that the shocks moving through the inner ring have started interacting with less dense circumstellar material, probably beyond the inner ring. We find significant changes in the X-ray line flux ratios (among H- and He-like Si and Mg ions) in 2018, consistent with changes in the thermal conditions of the X-ray emitting plasma that we infer based on the broadband spectral analysis. Post-shock electron temperatures suggested by line flux ratios are in the range $\sim$0.8 - 2.5 keV as of 2018. We do not yet observe any evidence of substantial abundance enhancement, suggesting that the X-ray emission component from the reverse-shocked metal-rich ejecta is not yet significant in the observed X-ray spectrum.

Accepted for publication by ApJ. 23 pages, 14 figures, and 3 tables

References in corpus (12)

• HI4PI: A full-sky HI survey based on EBHIS and GASS
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• The Destruction of the Circumstellar Ring of SN 1987A
• Collisionless shock heating of heavy ions in SN 1987A
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• Evolutionary Status of SNR 1987A at the Age of Eighteen
• Chandra LETG Observations of Supernova Remnant 1987A
• Chandra HETG Spectra of SN 1987A at 20 years
• Probing Elemental Abundances in SNR 1987A Using XMM-Newton
• Thermal Emission and Radioactive Lines, but No Pulsar, in the Broadband X-Ray Spectrum of Supernova 1987A
• Final Spitzer IRAC Observations of the Rise and Fall of SN 1987A
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Cited by in corpus (11)

• JWST NIRSpec observations of Supernova 1987A -- from the inner ejecta to the reverse shock
• Additional evidence for a pulsar wind nebula in the heart of SN 1987A from multi-epoch X-ray data and MHD modeling
• Latest Evolution of the X-Ray Remnant of SN 1987A: Beyond the Inner Ring
• Mid-infrared imaging of Supernova 1987A
• Plasma heating and particle acceleration in collisionless shocks through astrophysical observations
• Tracing the ejecta structure of SN 1987A: Insights and diagnostics from 3D MHD simulations
• Discovery of Year-Scale Time Variability from Thermal X-ray Emission in Tycho's Supernova Remnant
• Polarized radio emission unveils the structure of the pre-supernova circumstellar magnetic field and the radio emission in SN1987A
• Unusual X-ray Oxygen Line Ratios of SN 1987A Arising From the Absorption of Galactic Hot Interstellar Medium
• XMM-Newton Observations of the High Temperature Plasma in the Large Magellanic Cloud Supernova Remnant N132D
• Measuring the initial mass of 44Ti in SN 1987A through the 44Sc emission line