XMM-Newton observation of a sample of four close dSph galaxies

Abstract

We present the results of the analysis of deep archival \sat\ observations towards the dwarf spheroidal galaxies Draco, Leo I, Ursa Major II and Ursa Minor in the Milky Way neighbourhood. The X-ray source population is characterized and cross-correlated with available databases with the aim to infer their nature. We also investigate if intermediate-mass black holes are hosted in the center of these galaxies. In the case of Draco, we detect 96 high-energy sources, two of them being possibly local stars, while no evidence for any X-ray emitting central compact object is found. Towards the Leo I and UMa II field of view we reveal 116 and 49 X-ray sources, respectively. None of them correlates with the putative central black holes and only one is likely associated with a UMa II local source. The study of the UMi dwarf galaxy shows 54 high-energy sources and a possible association {with a source at the dSph center}. We put an upper limit to the central compact object luminosity of 4.02$\times$10${}^{33}$ erg/s. Furthermore, via the correlation with a radio source near the galactic center, we get that the putative black hole should have a mass of $\left(2.76_{-2.54}^{+32.00}\right)\times 10^6{M}_{\odot }$ and be radiatively inefficient. This confirms a previous result obtained by using Chandra data alone.

MNRAS, in press, tables available on line

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Cited by in corpus (11)

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• Classification of low-luminosity stellar X-ray sources in the field of the Draco dwarf spheroidal galaxy
• XMM-Newton study of X-ray sources in the field of Willman 1 dwarf spheroidal galaxy
• XMM-Newton study of the Sculptor dwarf spheroidal galaxy
• Exploring the evolution of a dwarf spheroidal galaxy with SPH simulations: II. AGN feedback
• Multiwavelength survey of X-ray sources in the Sculptor Dwarf Spheroidal Galaxy
• Searching for Intermediate Mass Black Holes in the Milky Way's galactic halo
• Multi-component, axisymmetric dynamical models of dSphs based on distribution functions: inferences on dark matter and intermediate-mass black holes in Draco and Ursa Minor