ESO VERY LARGE TELESCOPE OPTICAL SPECTROSCOPY OF BL LACERTAE OBJECTS. IV. NEW SPECTRA AND PROPERTIES OF THE FULL SAMPLE




Landoni M, Falomo R, Treves A, Sbarufatti B, Barattini M, Decarli R, Kotilainen J

PublisherIOP PUBLISHING LTD

2013

The Astronomical Journal

ASTRONOMICAL JOURNAL

ASTRON J

ARTN 114

4

145

4

12

0004-6256

DOIhttps://doi.org/10.1088/0004-6256/145/4/114



We present the last chapter of a spectroscopy program aimed at deriving the redshift or a lower limit to the redshift of BL Lac objects using medium-resolution spectroscopy. Here we report new spectra for 33 BL Lac object candidates obtained in 2008-2009, confirming the BL Lac nature of 25 sources and obtaining new redshifts for 5 objects. These new observations are combined with our previous data in order to construct a homogeneous sample of similar to 70 BL Lac objects with high-quality spectroscopy. All these spectra can be accessed at the Web site http://www.oapd.inaf.it/zbllac/. The average spectrum, beaming properties of the full sample, discussion of intervening systems, and future perspectives are addressed.



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