A1 Refereed original research article in a scientific journal
EUROPEAN SOUTHERN OBSERVATORY VERY LARGE TELESCOPE OPTICAL SPECTROSCOPY OF BL LACERTAE OBJECTS. III. AN EXTENSION OF THE SAMPLE
Authors: Sbarufatti B, Ciprini S, Kotilainen J, Decarli R, Treves A, Veronesi A, Falomo R
Publisher: IOP PUBLISHING LTD
Publication year: 2009
Journal: Bulletin of the American Astronomical Society
Journal name in source: ASTRONOMICAL JOURNAL
Journal acronym: ASTRON J
Volume: 137
Issue: 1
First page : 337
Last page: 346
Number of pages: 10
ISSN: 0004-6256
DOI: https://doi.org/10.1088/0004-6256/137/1/337
Abstract
We present results of an ongoing program at the European Southern Observatory Very Large Telescope for spectroscopy of BL Lac objects (BLLs) lacking a firm redshift estimate, and here we report on 15 objects. For 11 sources we confirm the BL Lac classification, and determine new redshifts for three objects, one with weak emission lines (PKS 1057 - 79, z = 0.569) and two with absorptions from the host galaxy (RBS 1752, z = 0.449; RBS 1915, z = 0.243); moreover, a subdamped Ly alpha system is detected in the direction of the BL Lac PKS 0823 - 223 (z >= 0.911). For the remaining eight BLLs, from the very absence of absorption lines of the host galaxy, lower limits to the redshift are deduced with z(min) 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).
We present results of an ongoing program at the European Southern Observatory Very Large Telescope for spectroscopy of BL Lac objects (BLLs) lacking a firm redshift estimate, and here we report on 15 objects. For 11 sources we confirm the BL Lac classification, and determine new redshifts for three objects, one with weak emission lines (PKS 1057 - 79, z = 0.569) and two with absorptions from the host galaxy (RBS 1752, z = 0.449; RBS 1915, z = 0.243); moreover, a subdamped Ly alpha system is detected in the direction of the BL Lac PKS 0823 - 223 (z >= 0.911). For the remaining eight BLLs, from the very absence of absorption lines of the host galaxy, lower limits to the redshift are deduced with z(min) 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).
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