European Southern Observatory Very Large Telescope Optical Spectroscopy of Bl Lacertae Objects. Iii. an Extension of the Sample

نویسندگان

  • B. Sbarufatti
  • S. Ciprini
  • J. Kotilainen
  • R. Decarli
  • A. Treves
  • A. Veronesi
  • R. Falomo
چکیده

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 Lyα 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 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). Key word: BL Lacertae objects: general

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Eso-vlt Optical Spectroscopy of Bl Lac Objects: I. New Redshifts

We report redshift measurements for 12 BL Lacertae objects from a program aimed at obtaining high signal to noise (up to ∼ 500) 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 ∼ 1 ˚ A. The new redshifts fall in the 0.2−1.3 interval. For...

متن کامل

Eso Vlt Optical Spectroscopy of Bl Lacertae Objects. Iii. an Extension of the Sample

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); ...

متن کامل

Eso-vlt Optical Spectroscopy of Bl Lac Objects: Ii. New Redshifts, Featureless Objects and Classification Assessments

We report on ESO Very Large Telescope optical spectroscopy of 42 BL Lacertae objects of unknown redshift. Nuclear emission lines were observed in 12 objects, while for another six we detected absorption features due to their host galaxy. The new high S/N spectra therefore allow us to measure the redshift of 18 sources. Five of the observed objects were reclassified either as stars or quasars, a...

متن کامل

TeV Gamma-Ray Observations of Southern Hemisphere BL Lacertae Objects with CANGAROO-II/III Telescope

Since 1999, several BL Lac objects, such as PKS 2155–304 (z=0.116) and PKS 2005–489 (z=0.072) have been observed with the CANGAROO-II imaging atmospheric Cherenkov telescope. We obtained flux upper limits for these objects. Here we present the results of our observations of these objects, particularly those observed since 2000, and discuss the implications for the emission models and the absorp...

متن کامل

Multiwavelength Observations of a Flare from Markarian 501

We present multiwavelength observations of the BL Lacertae object Markarian 501 (Mrk 501) in 1997 between April 8 and April 19. Evidence of correlated variability is seen in very high energy (VHE; E * 350 GeV) gray observations taken with the Whipple Observatory g-ray telescope, data from the Oriented Scintillation Spectrometer Experiment of the Compton Gamma Ray Observatory, and quick-look res...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2008