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arXiv · 1805.08870

NuSTAR Detection of a Hard X-ray Source in the Supernova Remnant - Molecular Cloud Interaction Site of IC 443

Shuo Zhang·Xiaping Tang·Xiao Zhang·Lei Sun·Eric V. Gotthelf·Zhi-Yu Zhang·Hui Li·Allen Cheng·Dheeraj Pasham·Frederick K. Baganoff·Kerstin Perez·Charles J. Hailey·Kaya Mori
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Abstract

We report on a broadband study of a complex X-ray source (1SAX J0618.0+2227) associated with the interaction site of the supernova remnant (SNR) IC 443 and ambient molecular cloud (MC) using NuSTAR, XMM_Newton, and Chandra observations. Its X-ray spectrum is composed of both thermal and non-thermal components. The thermal component can be equally well represented by either a thin plasma model with kT=0.19 keV or a blackbody model with kT=0.11 keV. The non-thermal component can be fit with either a power-law with Gamma~1.7 or a cutoff power-law with Gamma~1.5 and a cutoff energy at E_cut~18 keV. Using the newly obtained NuSTAR dataset, we test three possible scenarios for isolated X-ray sources in the SNR-MC interaction site: 1) pulsar wind nebula (PWN); 2) SNR ejecta fragment; 3) shocked molecular clump. We conclude that this source is most likely composed of a SNR ejecta (or a PWN) and surrounding shocked molecular clumps. The nature of this hard X-ray source in the SNR-MC interaction site of IC 443 may shed light on unidentified X-ray sources with hard X-ray spectra in rich environments for star forming regions, such as the Galactic center.

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Shuo Zhang, Xiaping Tang, Xiao Zhang, Lei Sun, Eric V. Gotthelf, Zhi-Yu Zhang, Hui Li, Allen Cheng, Dheeraj Pasham, Frederick K. Baganoff, Kerstin Perez, Charles J. Hailey, Kaya Mori. 2018-05-22. NuSTAR Detection of a Hard X-ray Source in the Supernova Remnant - Molecular Cloud Interaction Site of IC 443. https://doi.org/10.3847/1538-4357%2Faabe7c

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