X-Ray Sources in the Dwarf Spheroidal Galaxy Draco
Abstract
We present the spectral analysis of an 87 ks XMM-Newton observation of Draco, a nearby dwarf spheroidal galaxy. Of the approximately 35 robust X-ray source detections, we focus our attention on the brightest of these sources, for which we report X-ray and multiwavelength parameters. While most of the sources exhibit properties consistent with active galactic nuclei, few of them possess the characteristics of low-mass X-ray binaries (LMXBs) and cataclysmic variable (CVs). Our analysis places constraints on the population of X-ray sources with LX > 3 × 1033 erg s-1 in Draco, suggesting that there are no actively accreting black hole and neutron star binaries. However, we find four sources that could be quiescent state LMXBs/CVs associated with Draco. We also place constraints on the central black hole luminosity and on a dark matter decay signal around 3.5 keV.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2016
- DOI:
- 10.3847/0004-637X/821/1/54
- arXiv:
- arXiv:1505.00216
- Bibcode:
- 2016ApJ...821...54S
- Keywords:
-
- dark matter;
- galaxies: dwarf;
- galaxies: individual: Draco dwarf;
- novae;
- cataclysmic variables;
- stars: carbon;
- X-rays: binaries;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- Accepted for publication in ApJ