The X-ray nature of the nucleus in Seyfert 2 galaxy NGC 7590
Abstract
We present the results of the Chandra high-resolution observation of the Seyfert 2 galaxy NGC 7590. This object was reported to show no X-ray absorption in the low-spatial resolution ASCA data. The XMM-Newton observations show that the X-ray emission of NGC 7590 is dominated by an off-nuclear ultra-luminous X-ray source (ULX) and extended emissions from the host galaxy, and the nucleus is rather weak, likely hosting a Compton-thick AGN. Our recent Chandra observation of NGC 7590 enables us to effectively remove the X-ray contamination from the ULX and the extended component. The nuclear source remains undetected at the flux level of ~ 4 × 10-15 erg cm-2 s-1. Although not detected, the Chandra data give a 2-10 keV flux upper limit of ~ 6.1 × 10-15 erg cm-2 s-1 (at a 3σ level), a factor of three less than the XMM-Newton value, strongly supporting the Compton-thick nature of the nucleus. In addition, we detected five off-nuclear X-ray point sources within the galaxy's D25 ellipse, all with 2 - 10 keV luminosity above 2 × 1038 erg s-1 (assuming the distance of NGC 7590). In particular, the ULX previously identified by ROSAT data is resolved by Chandra into two distinct X-ray sources. Our analysis highlights the importance of high spatial resolution images in discovering and studying ULXs.
- Publication:
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Research in Astronomy and Astrophysics
- Pub Date:
- September 2012
- DOI:
- 10.1088/1674-4527/12/9/005
- arXiv:
- arXiv:1203.5488
- Bibcode:
- 2012RAA....12.1247S
- Keywords:
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- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 8 pages, 5 figures, RAA accepted