Fenómenos disruptivos de marea descubiertos por XMM-Newton// tidal disruption candidates from the XMM-Newton

Resumen

According to our current picture of the Universe, it has been suggested that the nucleus of every galaxy hosts a black hole. While it has been demonstrated that active galactic nuclei (AGN) powered by gas accretion onto supermassive black holes (SMBH s) populate the cores of a number of galaxies, confirmation of their lurking in a dormant state within non-active galaxies is difficult to obtain. A complete census of relic SMBHs is fundamental to constrain the accretion history of the Universe. E stablished evidence for the presence of a nuclear SMBH in a handful of non-active galaxies favours the conjecture that most galaxies harbour a SMBH. Unfortunately, the approach used for that cases, that relies on the study of spatially resolved stell ar/gas dynamics, can only be used for 20-30 nearby galaxies even with the high resolution of the Hubble Space Telescope. Alternatively to the stellar dynamics approach, an unavoidable consequence of the existence of remnant SMBHs at the nucleus of op tically non-active galaxies is the detection of flare radiation produced when a star is tidally disrupted and accreted by SMBHs. These tidal disruption events would generate outbursts of EUV/X-ray radiation decaying on a time scale of several months to years. Although active galactic nuclei can also be susceptible to these phenomena, the most unambiguous cases for a stellar disruption come from host galaxies with no - or only faint - permanent activity. The detection of tidal disruption events i s one of the two important methods to detect SMBHs in normal galaxies, and it is not hitherto well explored. Due to the scarcity of detected tidal disruption events, the confirmation and follow-up of each new candidate is needed to strengthen the the ory through observational data, as well as to shed new light on the characteristics of this type of events. The identification of tidal disruption events requires the existence of two large area sensitive surveys performed at different epochs. Give n that earlier X-ray surveys have been hitherto exploited in this topic, the existence of a new catalogue is a prerequisite to detect new candidates. Data obtained with XMM-Newton while the satellite is maneuvering between observation targets have be en processed and source searched. On the order of 18000 sources covering ~45% of the sky have been detected, comprising the current XMM-Newton Slew Survey Source Catalogue. The aim of the work presented in this thesis is to provide a further...