TY - JOUR
T1 - The Cooling of the Central Compact Object in Cas A from 2006 to 2020
AU - Posselt, B.
AU - Pavlov, G. G.
N1 - Funding Information:
The scientific results reported in this paper are based on observations made by the Chandra X-ray Observatory. Support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Number GO0-21049X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. B.P. acknowledges funding from the UK Science and Technology Facilities Council (STFC) Grant Code ST/R505006/1.
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/6/1
Y1 - 2022/6/1
N2 - 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.
AB - 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.
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U2 - 10.3847/1538-4357/ac6dca
DO - 10.3847/1538-4357/ac6dca
M3 - Article
AN - SCOPUS:85133537612
SN - 0004-637X
VL - 932
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 83
ER -