ESO very large telescope optical spectroscopy of BL Lacertae objects. I. New redshifts



: Sbarufatti B, Treves A, Falomo R, Heidt J, Kotilainen J, Scarpa R

Publisher: IOP PUBLISHING LTD

: 2005

: Bulletin of the American Astronomical Society

: ASTRONOMICAL JOURNAL

: ASTRON J

: 129

: 2

: 559

: 566

: 8

: 0004-6256

DOI: https://doi.org/10.1086/427138


We report redshift measurements for 12 BL Lacertae objects from a program aimed at obtaining high signal-to-noise ratio (up to similar to500) optical spectroscopy of a mixed sample of objects. The new observations, gathered with the 8 m ESO Very Large Telescope, allowed us to detect weak spectral features down to a line equivalent width as small as similar to1 Angstrom. The new redshifts fall in the 0.2-1.3 interval. For nine objects we observe emission lines from the active nucleus. In the remaining three cases absorption lines from the host galaxy are found. For two objects we also detect absorption lines from intervening systems.



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