The Chandra Local Volume Survey: The X-Ray Point-source Catalog of NGC 300
Abstract
We present the source catalog of a new Chandra ACIS-I observation of NGC 300 obtained as part of the Chandra Local Volume Survey. Our 63 ks exposure covers ~88% of the D 25 isophote (R ≈ 6.3 kpc) and yields a catalog of 95 X-ray point sources detected at high significance to a limiting unabsorbed 0.35-8 keV luminosity of ~1036 erg s-1. Sources were cross-correlated with a previous XMM-Newton catalog, and we find 75 "X-ray transient candidate" sources that were detected by one observatory, but not the other. We derive an X-ray scale length of 1.7 ± 0.2 kpc and a recent star formation rate of 0.12 M ⊙ yr-1 in excellent agreement with optical observations. Deep, multi-color imaging from the Hubble Space Telescope, covering ~32% of our Chandra field, was used to search for optical counterparts to the X-ray sources, and we have developed a new source classification scheme to determine which sources are likely X-ray binaries, supernova remnants, and background active galactic nucleus candidates. Finally, we present the X-ray luminosity functions (XLFs) at different X-ray energies, and we find the total NGC 300 X-ray point-source population to be consistent with other late-type galaxies hosting young stellar populations (lsim 50 Myr). We find that XLF of sources associated with older stellar populations has a steeper slope than the XLF of X-ray sources coinciding with young stellar populations, consistent with theoretical predictions.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 2012
- DOI:
- 10.1088/0004-637X/758/1/15
- arXiv:
- arXiv:1208.1510
- Bibcode:
- 2012ApJ...758...15B
- Keywords:
-
- galaxies: individual: NGC 300;
- galaxies: spiral;
- X-rays: binaries;
- X-rays: galaxies;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 23 pages, 13 figures. Accepted to ApJ