The extreme high frequency peaked BL Lac 1517+656

Astronomy & Astrophysics 352, 395 (1999)

V. Beckmann [1][2], N. Bade [1] und O. Wucknitz [1]

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

Abstract

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 z = 0.702 this object has an absolute magnitude of MB = -26.4 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 > 2*1012 solar masses and a high velocity dispersion > 350 km sec-1.

Key words: BL Lacertae objects: general - BL Lacertae objects: individual: 1517+656 - Galaxies: distances and redshifts - Cosmology: gravitational lensing

Contact: Volker Beckmann.

Preprint (compressed PS-File, 70 Kb)

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