EDP Sciences
Free access
Volume 396, Number 3, December IV 2002
Page(s) 787 - 792
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20021391

A&A 396, 787-792 (2002)
DOI: 10.1051/0004-6361:20021391

BL Lac identification for the ultraluminous X-ray source observed in the direction of NGC 4698

L. Foschini1, L. C. Ho2, N. Masetti1, M. Cappi1, M. Dadina1, L. Bassani1, G. Malaguti1, E. Palazzi1, G. Di Cocco1, P. Martini2, S. Ravindranath2, 3, J. B. Stephen1, M. Trifoglio1 and F. Gianotti1

1  Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-CNR) - Sezione di Bologna (Formerly Istituto TeSRE - CNR.) , via Gobetti 101, 40129, Bologna, Italy
2  The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101, USA
3  Department of Astronomy, University of California, Berkeley, CA 94720, USA

(Received 5 August 2002 / Accepted 20 September 2002 )

We report the identification of the optical and radio counterparts of the ultraluminous X-ray (ULX) source XMMU J124825.9+083020 (NGC 4698-ULX1). The optical spectrum taken with the VLT yields a redshift of z=0.43, which implies that the ULX is not associated with the nearby galaxy NGC 4698. The spectral energy distribution calculated from the available data indicates that the source is likely to be a BL Lac object. The possible synchrotron peak at X-ray energies suggests that this source may be a $\gamma$-ray emitter.

Key words: galaxies: active -- galaxies: Seyfert -- galaxies: BL Lacertae objects: general

Offprint request: L. Foschini, foschini@bo.iasf.cnr.it

SIMBAD Objects

© ESO 2002