2008/10/20 by B. Sbarufatti, Sbarufatti, B., S. Ciprini +13
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.0810.3563
16 pages, 5 figures, 3 tables, accepted for publication on AJ
arxiv created 2008/10/20 · openalex publication_date 2008/10/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present results of an ongoing program at the ESO VLT for spectroscopy of BL Lac objects lacking a firm redshift estimate and here we report on 15 objects. For 11 sources we confirm the BL Lac classification, and we determine new redshifts for 3 objects, 1 with weak emission lines (PKS 1057-79, z=0.569) and 2 with absorptions from the host galaxy (RBS 1752, z=0.449; RBS 1915, z=0.243); moreover a sub Damped Lyman Alpha (sub-DLA) system is detected in the direction of the BL Lac PKS 0823-223 (z>=0.911). For the remaining 8 BL Lacs, from the very absence of absorption lines of the host galaxy, lower limits to the redshift are deduced with zmin in the interval 0.20-0.80. The remaining three sources are reclassified as a FSRQ (PKS 1145-676, z=0.210; TXS 2346+052, z=0.419) and a misclassified galactic star (PMNJ 1323-3652).