Nonthermal X-Rays from Supernova Remnant G330.2+1.0 and the Characteristics of its Central Compact Object

• Published in: The Astrophysical journal Vol. 695; no. 1; pp. 431 - 441
• Main Authors: Park, Sangwook, Kargaltsev, Oleg, Pavlov, George G, Mori, Koji, Slane, Patrick O, Hughes, John P, Burrows, David N, Garmire, Gordon P
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 10.04.2009; IOP
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; ISM: individual (SNR G330.2+1.0); Neutron stars; Supernova remnants; X-rays: stars; Compact objects; stars: neutron
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/695/1/431

We present results from our X-ray data analysis of the supernova remnant (SNR) G330.2+1.0 and its central compact object (CCO), CXOU J160103.1-513353 (J1601 hereafter). Using our XMM-Newton and Chandra observations, we find that the X-ray spectrum of J1601 can be described by neutron star atmosphere models (T {infinity} ~ 2.5-5.5 MK). Assuming the distance of d ~ 5 kpc for J1601 as estimated for SNR G330.2+1.0, a small emission region of R ~ 0.4-2 km is implied. X-ray pulsations previously suggested by Chandra are not confirmed by the XMM-Newton data, and are likely not real. However, our timing analysis of the XMM-Newton data is limited by poor photon statistics, and thus pulsations with a relatively low amplitude (i.e., an intrinsic pulsed fraction less than 40%) cannot be ruled out. Our results indicate that J1601 is a CCO similar to that in the Cassiopeia A SNR. X-ray emission from SNR G330.2+1.0 is dominated by power-law continuum ( ~ 2.1-2.5) which primarily originates from thin filaments along the boundary shell. This X-ray spectrum implies synchrotron radiation from shock-accelerated electrons with an exponential roll-off frequency nrolloff ~ 2-3 X 1017 Hz. For the measured widths of the X-ray filaments (D ~ 0.3 pc) and the estimated shock velocity (vs ~ a few X 103 km s-1), a downstream magnetic field B ~ 10-50 mG is derived. The estimated maximum electron energy E max ~ 27-38 TeV suggests that G330.2+1.0 is a candidate TeV g-ray source. We detect faint thermal X-ray emission in G330.2+1.0. We estimate a low preshock density n 0 ~ 0.1 cm-3, which suggests a dominant contribution from an inverse Compton mechanism (than the proton-proton collision) to the prospective g-ray emission. Follow-up deep radio, X-ray, and g-ray observations will be essential to reveal the details of the shock parameters and the nature of particle accelerations in this SNR.