Abstract

We report the results of the analysis of an archive Chandra observation of the Ursa Minor spheroidal galaxy, one of the closest Milky Way satellites, searching for signatures from the intermediate mass black hole possibly hosted in the center of the galaxy. We identified an X-ray source with a detection confidence as low as ≃2.5σ and with an estimated unabsorbed flux in the 0.5-7 keV band of ≃4.9×10-15 erg s-1 cm-2 and at a few arcseconds from the reported center of the galaxy. The source is spatially coincident with a radio object (having flux density of ≃7.1 mJy at 1.4 GHz) already observed in the NRAO VLA Sky Survey. In the accreting black hole scenario, depending on the used fundamental plane relation, one estimates an accretor mass of (2.9-2.7+33.6)×106M⊙ or (11.7-9.7+57.1)×106M⊙. Relaxing the assumption for a flat radio spectrum, the minimum black hole mass would result in the range 5×104M⊙-5×105M⊙, i.e. still consistent with an intermediate mass black hole scenario. The compact object seems to radiate at a very tiny fraction of the associated Eddington luminosity.

Autore Pugliese

• Ingrosso Gabriele , Nucita Achille , De Paolis Francesco

Tutti gli autori

• A.A. Nucita , L. Manni , F. De Paolis , G. Ingrosso

Titolo volume/Rivista

NEW ASTRONOMY

Anno di pubblicazione

2013

ISSN

1384-1076

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

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Numero di citazioni Scopus

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Ultimo Aggiornamento Citazioni

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Settori ERC

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Codici ASJC

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