Related papers: Cassiopeia A and its Clumpy Presupernova Wind
We study the dust evolution in the supernova remnant Cassiopeia A. We follow the processing of dust grains that formed in the Type II-b supernova by modelling the sputtering of grains. The dust is located in dense ejecta clumps crossed by…
We propose a model for the hard X-ray (> 10 keV) emission observed from the supernova remnant Cas A. Lower hybrid waves are generated in strong (mG) magnetic fields, generally believed to reside in this remnant, by shocks reflected from…
Observations of the B0.2V star tau Scorpii have revealed unusual stellar wind characteristics: red-shifted absorption in the far-ultraviolet O VI resonance doublet up to +250 km/s, and extremely hard X-ray emission implying gas at…
The circumstellar dust shells of intermediate initial-mass (about 1 to 8 solar masses) evolved stars are generated by copious mass loss during the asymptotic giant branch phase. The density structure of their circumstellar shell is the…
We present a comparative analysis of supernova remnant Cassiopeia A based on two deep, narrow-band images covering the [Fe II] 1.644um + [Si I] 1.645um lines obtained in 2013 and 2020 with the same instruments on the UKIRT 3.8m telescope.…
We present Hubble Space Telescope WFC3/IR images of the Cassiopeia A supernova remnant that survey its high-velocity, S-rich debris in the NE jet and SW counterjet regions through [S III] 9069, 9531 and [S II] 10,287 - 10,370 line…
Two images of Cassiopeia A obtained at 24 micrometer with the Spitzer Space Telescope over a one year time interval show moving structures outside the shell of the supernova remnant to a distance of more than 20 arcmin. Individual features…
Near-infrared spectra (0.95 - 2.4 micron) of the Cassiopeia A and Kepler supernova remnants (SNRs) are presented. Low-dispersion (R = 700) spectra were obtained for five bright fast-moving ejecta knots (FMKs) at two locations on the main…
Dense, fast-moving ejecta knots in supernova remnants are prime sites for molecule and dust formation. We present SOFIA far-IR spectrometer FIFI-LS observations of CO-rich knots in Cas A which cover a ~1 square arc minute area of the…
The recent survey of the core-collapse supernova remnant Cassiopeia A (CasA) with the MIRI instrument on board the James Webb Space Telescope (JWST) revealed a large structure in the interior region, referred to as the "Green Monster".…
We investigate the properties of Fe-rich knots on the east limb of the Cassiopeia A supernova remnant using observations with Chandra/ACIS and analysis methods developed in a companion paper. We use the fitted ionization age and electron…
We present the first X-ray expansion measurement of the SNR Cas A. We compared new ROSAT to archived Einstein HRI images with a separation of 17 years. The remnant is seen to be expanding, on average, at a rate of 0.20 %/yr, which is twice…
We compare the radio and soft X-ray brightness as a function of position within the young supernova remnant Cassiopeia A. A moderately strong correlation (r = 0.7) was found between the X-ray emission (corrected for interstellar absorption)…
Using data from the Chandra X-Ray Observatory, we revisited the reverse shock in the supernova remnant (SNR) Cassiopeia A.Based on the spectroscopic of a series of annuli in the northwest (NW) and southeast (SE), we get the radial profiles…
Observations of the ejecta of core-collapse supernovae have shown that dust grains form in over-dense gas clumps in the expanding ejecta. The clumps are later subject to the passage of the reverse shock and a significant amount of the newly…
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…
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…
We report 1405 MHz measurements of the flux density of the approximately 320 year old supernova remnant Cassiopeia A, relative to the flux density of Cygnus A, made between 1995 and 1999. When compared to measurements made between 1957 and…
Using the 3.5-m Herschel Space Observatory, imaging photometry of Cas A has been obtained in six bands between 70 um and 500 um with the PACS and SPIRE instruments, with angular resolutions ranging from 6 to 37". In the outer regions of the…
A very small fraction of (runaway) massive stars have masses exceeding $60$-$70\, \rm M_{\odot}$ and are predicted to evolve as Luminous-Blue-Variable and Wolf-Rayet stars before ending their lives as core-collapse supernovae. Our 2D…