ﻻ يوجد ملخص باللغة العربية
Core-collapse supernovae (SNe) expand into a medium created by winds from the pre-SN progenitor. The SN explosion and resulting shock wave(s) heat up the surrounding plasma, giving rise to thermal X-ray emission, which depends on the density of the emitting material. Tracking the variation of the X-ray luminosity over long periods of time thus allows for investigation of the kinematics of the SN shock waves, the structure of the surrounding medium, and the nature of the progenitor star. In this paper X-ray observations of five of the oldest known X-ray supernovae - SN 1970G, SN 1968D, SN 1959D, SN 1957D and SN 1941C - are analyzed, with the aim of reconstructing their light curves over several decades. For those supernovae for which we can extract multi-epoch data, the X-ray luminosity appears to decline with time, although with large error bars. No increase in the X-ray emission from SN 1970G is found at later epochs, contrary to previous reports. All five SNe show X-ray luminosities that are of comparable magnitude. We compare the late-time X-ray luminosities of these SNe to those of supernova remnants (SNRs) in the Galaxy which are a few hundred years old, and find that when the tentative decline is taken into account, the luminosity of the old SNe studied herein could fall below the luminosity of some of the younger SNRs within a few hundred years. However, the X-ray luminosity should begin to increase as the SNe expand in the Sedov phase, thus reaching that of the observed SNRs.
We present the results of a spectral analysis of the central region of the mixed-morphology supernova remnant HB 9. A prior Ginga observation of this source detected a hard X-ray component above 4 keV and the origin of this particular X-ray component
We report a discovery of diffuse X-ray emission around the supernova remnant (SNR) G106.3+2.7, which is associated with VER J2227+608 and HAWC J2227+610 and is known as a candidate for a PeV cosmic ray accelerator (PeVatron). We analyze observational
We present X-ray proper-motion measurements of the forward shock and reverse-shocked ejecta in Tychos supernova remnant, based on three sets of archival Chandra data taken in 2000, 2003, and 2007. We find that the proper motion of the edge of the rem
We present the first dedicated X-ray study of the supernova remnant (SNR) G32.8-0.1 (Kes 78) with Suzaku. X-ray emission from the whole SNR shell has been detected for the first time. The X-ray morphology is well correlated with the emission from the
NuSTAR observed G1.9+0.3, the youngest known supernova remnant in the Milky Way, for 350 ks and detected emission up to $sim$30 keV. The remnants X-ray morphology does not change significantly across the energy range from 3 to 20 keV. A combined fit