Free access article

A&A 410, 951-959 (2003)
DOI: 10.1051/0004-6361:20031322

XMM-Newton study of the Serpens star-forming region

T. Preibisch

Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
(Received 23 June 2003 / Accepted 19 August 2003)

Abstract
We analyze a XMM-Newton X-ray observation of the Serpens dark cloud with a total MOS-equivalent exposure time of 57 ksec. We find 45 individual X-ray sources. None of the class 0 protostars, only one of the class I protostars, and two of the flat-spectrum objects in the region are detected in X-rays. The optically invisible flat-spectrum source EC 95, a very young intermediate mass object, is the strongest X-ray source in the Serpens cloud. The analysis of its X-ray spectrum shows that the hydrogen column density towards EC 95 is considerably lower than expected from the extinction determined from near-IR spectroscopy and photometry. Possible reasons for this inconsistency are discussed.

Key words: open clusters and associations: individual: Serpens dark cloud -- stars: formation -- stars: coronae -- stars: low-mass, brown dwarfs -- stars: pre-main sequence -- X-rays: stars

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© ESO 2003

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