The γ-ray Pulsar J0633+0632 in X-rays

Abstract

We analysed Chandra observations of the bright Fermi pulsar J0633+0632 and found evidence of an absorption feature in its spectrum at 804 +42 −26 eV (the errors are at 90% confidence) with equivalent width of 63 +47 −36 eV. In addition, we analysed in detail the X-ray spectral continuum taking into account correlations between the interstellar absorption and the distance to the source. We confirm early findings that the spectrum contains non-thermal and thermal components. The latter is equally well described by the blackbody and magnetised atmosphere models and can be attributed to the emission from the bulk of the stellar surface in both cases. The distance to the pulsar is constrained in a range of 1-4 kpc from the spectral fits. We infer the blackbody surface temperature of 108 +22 −14 eV, while for the atmosphere model, the temperature, as seen by a distant observer, is 53 +12 −7 eV. In the latter case, J0633+0632 is one of the coldest middle-aged isolated neutron stars. Finally, it powers an extended pulsar wind nebula whose shape suggests a high pulsar proper motion. Looking backwards the direction of the presumed proper motion, we found a likely birthplace of the pulsar-the Rosette nebula, a 50-Myr-old active star-forming region located at about 1.5 • from the pulsar. If true, this constrains the distance to the pulsar in the range of 1.2-1.8 kpc.

XMM–Newton observations of a gamma-ray pulsar J0633+0632: pulsations, cooling and large-scale emission

“…We analysed the XMM-Newton observations of the J0633 γray pulsar. We confirmed previous investigations (Ray et al 2011;Danilenko et al 2015) that the pulsar spectrum contains thermal and non-thermal components. The former can be equally well fitted by either the blackbody or magnetized neutron star atmosphere models.…”

“…For these two models, our results are generally consistent with the results of that work, while the parameter uncertainties obtained here are much smaller. To our surprise, we found no evidence of the absorption spectral feature at 0.8 keV in the XMM-Newton data, whose presence in the Chandra data was claimed by Danilenko et al (2015). This becomes clear from examination of the residuals of the spectral fit by a purely continuum spectral model presented in Fig.…”

XMM-Newton and Chandra Observations of the Unidentified Fermi-LAT Source 3FGL J1016.5–6034: A Young Pulsar with a Nebula?

“…The general procedure is outlined e.g., in Section 2.1 of Danilenko et al (2015) and https://asd.gsfc.nasa.gov/ XSPECwiki/statistical_methods_in_XSPEC tended emission partially overlaps with one of MOS 1's damaged CCDs, and MOS2 has fewer net counts than the pn. Following the approach taken by, e.g., Younes et al (2016), we first extracted the background spectrum from the region shown by the dashed white circle in Figure 1.…”

Magnetic neutron star cooling and microphysics

“…Numbers 1 -41 enumerate the entries in Table 3 of Potekhin et al (2015). We have updated the data for object 4 according to Posselt et al (2013) and added objects 42 (XMMU J173203.3−344518, Klochkov et al 2015), 43 (CXOU J181852.0−150213, Klochkov et al 2016), and 44 (PSR J0633+0632, Danilenko et al 2015;Karpova et al 2017). The errorbars and arrows for magnetars are drawn in red color.…”

“…For the thermal luminosity of the neutron star CXO J232327.9+584842 in the supernova remnant Cassiopeia A (object number 4, often dubbed Cas A NS) we have adopted improved observational data onL (Posselt et al 2013). We have supplemented this catalog with three neutron stars with recently measured thermal fluxes: two neutron stars with carbon envelopes (sources 42 and 43, Klochkov et al 2015Klochkov et al , 2016, and one pulsar (source 44, Danilenko et al 2015;Karpova et al 2017; in this case, we adopt the interpretation of the thermal spectrum with the model of a partially ionized magnetized hydrogen atmosphere nsmax, Ho et al 2008). Objects 25 through 41 (red symbols) are magnetars.…”