Optical imaging and spectroscopy of BL Lac objects

نویسندگان

  • Renato Falomo
  • Marie-Helene Ulrich
چکیده

We present optical images and spectroscopy for a dozen of BL Lac objects. Most of these objects were not previously studied and we give for the first time the properties of their host galaxies. The properties of the new host galaxies are generally consistent with those derived in previous optical studies. We found a case (1101-23) where the external isophotes of the galaxy are clearly boxy. In addition we gathered spectroscopy for several BL Lac objects with unknown redshift and for companion galaxies. This allowed us to derive a tentative redshift for two new BL Lacs and to investigate the environment around PKS 0829+04. These data complement existing data available in the literature on host galaxies of BL Lacs and their (close) environments.

برای دانلود رایگان 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

Optical spectroscopy of BL Lacertae objects . Broad lines , companion galaxies and redshift lower limits

Aims. We present optical spectroscopy of a sample of BL Lac objects, to determine their redshift, to study their broad emission line properties and to characterize their close environment. Methods. Twelve objects were observed using the ESO 3.6m and the NOT 2.5m telescopes, obtaining spectra for the BL Lacs and for nearby sources. Results. For seven objects, nuclear emission lines and/or absorp...

متن کامل

Astronomy and Astrophysics the Extreme High Frequency Peaked Bl Lac 1517+656

We present optical spectroscopy data that allowed a measurement of the redshift for the X-ray selected BL Lacertae object 1517+656. With a redshift of z = 0.702 this object has an absolute magnitude of M B = −26.4 and is also an extremely powerful radio and X-ray source. Although being a high frequency peaked BL Lac, this object is one of the most luminous BL Lac objects known so far. Being als...

متن کامل

A Large Sample of Bl Lacs from Sdss and First

We present a large sample of 501 radio-selected BL Lac candidates from the combination of the Sloan Digital Sky Survey (SDSS) Data Release 5 optical spectroscopy and from the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) radio survey; this is one of the largest BL Lac samples yet assembled, and each object emerges with homogeneous data coverage. Each candidate is detected in the r...

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

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

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...

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

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2000