The Cooling of the Central Compact Object in Cas A from 2006 to 2020

B. Posselt, G. G. Pavlov

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7 Scopus citations


We report on the study of six Chandra observations (four epochs) of the Central Compact Object (CCO) in the Cassiopeia A supernova remnant with the ACIS instrument in the subarray mode. This mode minimizes spectrum-distorting instrumental effects such as pileup. The data were taken over a time span of ∼14 yr. If a non-magnetic carbon atmosphere is assumed for this youngest known CCO, then the temperature change is constrained to be Ṫ=-2900±600 K yr-1 or Ṫ=-4500±800 K yr-1 (1σ uncertainties) for constant or varying absorbing hydrogen column density. These values correspond to cooling rates of -1.5% ± 0.3% per 10 yr and -2.3% ± 0.4% per 10 yr, respectively. We discuss an apparent increase in the cooling rate in the last five years and the variations of the inferred absorbing hydrogen column densities between epochs. Considered together, these changes could indicate systematic effects such as caused by, e.g., an imperfect calibration of the increasing contamination of the ACIS filter.

Original languageEnglish (US)
Article number83
JournalAstrophysical Journal
Issue number2
StatePublished - Jun 1 2022

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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