Forum Springer Astron. Astrophys.
Forum Whats New Search Orders

Astron. Astrophys. 352, 395-398 (1999)

Table of Contents
Available formats: HTML | PDF | (gzipped) PostScript

The extreme high frequency peaked BL Lac 1517+656 *

V. Beckmann 1,2, N. Bade 1 and O. Wucknitz 1

1 Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany
2 Osservatorio Astronomico di Brera, Via Brera 28, 20121 Milano, Italy

Received 18 June 1999 / Accepted 4 October 1999


We present optical spectroscopy data that allowed a measurement of the redshift for the X-ray selected BL Lacertae object 1517+656. With a redshift of [FORMULA] this object has an absolute magnitude of [FORMULA] and is also an extremely powerful radio and X-ray source. Although being a high frequency peaked BL Lac, this object is one of the most luminous BL Lac objects known so far. Being also a candidate for gravitational lensing, this object is of high interest for the BL Lac research. Assuming several cosmological models and a realistic redshift for the lensed object, we find that 1517+656 has a mass [FORMULA] and a high velocity dispersion [FORMULA].

Key words: galaxies: BL Lacertae objects: general – galaxies: BL Lacertae objects: individual: 1517+656 – galaxies: distances and redshifts – cosmology: gravitational lensing

* Based on observations from the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Planck-Institut für Astronomie, Heidelberg, jointly with the Spanish National Commission for Astronomy

Send offprint requests to: V. Beckmann (vbeckmann@hs.uni-hamburg.de)

© European Southern Observatory (ESO) 1999

Online publication: December 2, 1999