CXOU J160103.1–513353: another central compact object with a carbon atmosphere?

¹ Institut für Astronomie und Astrophysik, Sand 1, 72076 Tübingen, Germany
e-mail: doroshv@astro.uni-tuebingen.de
² Space Research Institute of the Russian Academy of Sciences, Profsoyuznaya Str. 84/32, Moscow, 117997 Russia
³ Kazan (Volga region) Federal University, Kremlevskaja str., 18, Kazan, 420008, Russia

Received: 20 April 2018
Accepted: 14 June 2018

Abstract

We report on the analysis of XMM-Newton observations of the central compact object CXOU J160103.1–513353 located in the center of the non-thermally emitting supernova remnant (SNR) G330.2+1.0. The X-ray spectrum of the source is well described with either single-component carbon or two-component hydrogen atmosphere models. In the latter case, the observed spectrum is dominated by the emission from a hot component with a temperature ∼3.9 MK, corresponding to the emission from a hotspot occupying ∼1% of the stellar surface (assuming a neutron star with mass M  =  1.5 M_⊙, radius of 12 km, and distance of ∼5 kpc as determined for the SNR). The statistics of the spectra and obtained upper limits on the pulsation amplitude expected for a rotating neutron star with hot spots do not allow us to unambiguously distinguish between these two scenarios. We discuss, however, that while the non-detection of the pulsations can be explained by the unfortunate orientation in CXOU J160103.1–513353, this is not the case when the entire sample of similar objects is considered. We therefore conclude that the carbon atmosphere scenario is more plausible.