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

Abstract

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 ~ 14 years. If a non-magnetic carbon atmosphere is assumed for this youngest known CCO, then the temperature change is constrained to be $\dot{T}=-2900\pm 600$ K yr${}^{-1}$ or $\dot{T}=-4500\pm 800$ K yr${}^{-1}$ ($1\sigma$ uncertainties) for constant or varying absorbing hydrogen column density. These values correspond to cooling rates of $-1.5\pm 0.3$% per 10yr and $-2.3\pm 0.4$% per 10yr, 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.

Accepted for publication in ApJ, 6 pages, 2 figures, 2 tables

References in corpus (5)

• Evolution of a buried magnetic field in the central compact object neutron stars
• A dedicated Chandra ACIS observation of the central compact object in the Cassiopeia A supernova remnant
• Diffusive nuclear burning in cooling simulations and application to new temperature data of the Cassiopeia A neutron star
• X-ray bounds on cooling, composition, and magnetic field of the Cassiopeia A neutron star and young central compact objects
• Model-independent constraints on superfluidity from the cooling neutron star in Cassiopeia A

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