Detection of hard X-ray point sources above 10 keV in the NuSTAR Galactic Center Survey
Abstract
Beginning in October 2012, NuSTAR Galactic Center Survey has observed ~0.5 1 degree field around the Galactic Center with total exposure of ~1 Msec. The covered field contains a few thousand Chandra X-ray sources (Muno 2009) but their true nature is still unknown. NuSTAR has unambiguously detected more than a dozen hard X-ray point sources above 10 keV, including two known X-ray binaries during their outbursts. We found that all the NuSTAR point sources detected above 10 keV so far have Chandra X-ray counterparts. Hard X-ray detection of these point sources suggests they are either magnetic CVs with kT ~10-30 keV thermal spectra or X-ray binaries with power-law (black hole) or cut-off power-law spectra (neutron star), and they can be spectroscopically identified by jointly analyzing NuSTAR and Chandra/XMM-Newton data. Our preliminary spectral analysis revealed several NuSTAR sources with power-law spectra extending beyond 40 keV, indicating that they are potential black hole candidates. In this poster, we will present our source detection methods, spectral analysis, variability study and IR counterpart searches.
- Publication:
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American Astronomical Society Meeting Abstracts #223
- Pub Date:
- January 2014
- Bibcode:
- 2014AAS...22343803M