ULX – Ultraluminous X-ray sources – Master – MERATE (LC) – Ultraluminous X-ray sources in crowded fields – C. Salvaggio.

Introduction – Ultraluminous X-ray sources (ULXs) are X-ray binaries particularly luminous in the X-ray band, accreting above their Eddington limit. They are usually observed in nearby galaxies, distinct from the nuclear region. In most sources the nature of the accretor, a neutron star or a black hole, is unknown.

The thesis – ULXs catalogs are made using data of X-ray telescopes with different spatial resolution. As a consequence, collections of less luminous objects are sometimes indicated as ULXs. The aim of this thesis is to analyse X-ray data of a sample of galaxies crowded in X-ray sources including a number of ULXs, comparing data taken with different telescopes to distinguish ULXs from collections of non-resolved objects. The resulting population of sources will be studied in detail, both including spectral and temporal analysis. This work will help to identify contaminants in the existent catalogs of ULXs and to better characterize a population of still elusive sources.


[Image credit: NASA/JPL-Caltech]