Related papers: A Million-Second Chandra View of Cassiopeia A
The expansion structure of supernova remnants (SNRs) is important for understanding not only how heavy elements are distributed into space, but also how supernovae explode. The ejecta expansion structure of the young core-collapse SNR Cas A…
The Vela supernova remnant displays several ejecta, which are fragment-like features protruding beyond the front of its primary blast shock wave. They appear to be "shrapnel", bowshock-shaped relics of the supernova explosion. One of these…
We report the likely detection of near-infrared 2.29 $\mu$m first overtone Carbon Monoxide (CO) emission from the young supernova remnant Cassiopeia A (Cas A). The continuum-subtracted CO filter map reveals CO knots within the ejecta-rich…
Using optical and near-infrared images of the Cassiopeia A (Cas A) supernova remnant covering the time period 1951 to 2022, together with optical spectra of selected filaments, we present an investigation of Cas A's reverse shock velocity…
We present a long-exposure (~10 hr) image of the supernova (SN) remnant Cassiopeia A (Cas A) obtained with the UKIRT 3.8-m telescope using a narrow band filter centered at 1.644 um emission. The passband contains [Fe II] 1.644 um and [Si I]…
We present initial results of a 750 ks Chandra observation of the remnant of Kepler's supernova of AD 1604. The strength and prominence of iron emission, together with the absence of O-rich ejecta, demonstrate that Kepler resulted from a…
We continue our analysis of the Galactic oxygen-rich supernova remnant (SNR) G292.0+1.8, which was observed with the {\it Chandra X-ray Observatory}. The high angular resolution {\it Chandra} data resolve metal-rich ejecta knots as well as…
The supernova remnant Cassiopeia A (Cas A) is one of the few remnants in which it is possible to observe unshocked ejecta. A deep 1.64 micron image of Cas A shows a patch of diffuse emission from unshocked ejecta, as well as brighter…
Recent simulations have shown that asymmetries in the ejecta distribution of supernova remnants (SNR) can still reflect asymmetries from the initial supernova explosion. Thus, their study provides a great means to test and constrain model…
Probably not, but it is interesting nevertheless to investigate just how close Cas A might have come to generating such an event. Focusing on the northeast jet filaments, we analyze the polar regions of the recently acquired very deep 1 Ms…
Cassiopeia A (Cas A) supernova remnant shows strong radiation from radio to gamma-ray bands. The mechanism of gamma-ray radiation in Cas A and its possible contribution to PeV cosmic rays are still under debate. The X-ray imaging reveals an…
We analyze and model the infrared spectrum of the Cassiopeia A supernova remnant, with the aim of determining the masses of various elements in the unshocked ejecta. In this way we complement the survey of the X-ray emitting ejecta of Hwang…
Cassiopeia A (Cas A) as the nearby young remnant of a core-collapse supernova is the best candidate for astrophysical studies in supernova explosion and its environment. We studied hard X-ray emissions from Cas A using the ten-year data of…
We show that the explosive transition of the neutron star (NS) to a quark star (QS) (a Quark Nova) in Cassiopeia A (Cas A) a few days following the SN proper can account for several of the puzzling kinematic and nucleosynthetic features…
We identify a point-symmetric morphology of the supernova remnant (SNR) Cassiopeia A compatible with shaping by at least two, and more likely more than four, pairs of opposite jets, as expected in the jittering jets explosion mechanism…
We present results from two Chandra/ACIS observations of the so-called Vela ``Bullet D'' region on the eastern limb of the Vela supernova remnant. The Bullet D region is a bright X-ray feature, identified by Aschenbach et al. (1995) from…
In the framework of the study of supernova remnants and their complex interaction with the interstellar medium and the circumstellar material, we focus on the galactic supernova remnant W49B. Its morphology exhibits an X-ray bright…
A comparison of X-ray observations of the Cassiopeia A supernova remnant taken in 2000, 2002, and 2004 with the Chandra ACIS-S3 reveals the presence of several small scale features (<= 10 arcsec) which exhibit significant intensity changes…
We model the thermal dust emission from dust grains heated by synchrotron radiation and by particle collisions, under conditions appropriate for four different shocked and unshocked gas components of the Cassiopeia A (Cas A) supernova…
An analysis of a 29 ksec Chandra ACIS-S observation of the young, Cassiopeia-A like supernova remnant in the irregular galaxy NGC 4449 is presented. The observed 0.5-2.1 keV spectrum reveals the likely presence of several emission lines…