Related papers: A Search for Low-Luminosity BL Lacertae Objects
This paper concerns the relationship of BLLacs and flat spectrum weak emission-line galaxies. We compare the weak emission-line galaxies and the BLLacs in a sample of 57 flat spectrum objects (Marcha et al. 1996), using high-frequency radio…
We present the radio detection of 18 BL Lac objects from our survey of over 575 square degrees of sky. These 18 objects are located within 20 arcsec of the X-ray position, of which 11 have a measured red-shift. All candidates are radio…
The past 20 years have seen phenomenal progress in our understanding of BL Lac objects. They form part of the blazar class, which are radio-loud AGN whose relativistic jets are aligned along our line of sight. Several critical milestones…
We report on the optical properties of a sample of 30 BL Lac host galaxies in the redshift range $0.03<z<0.2$, as derived from HST observations. All galaxies are fully resolved in the WFPC2 (F702W filter) images, allowing a quantitative…
We present a sample of 386 BL Lacertae (BL Lac) candidates identified from 2860 deg^2 of the Sloan Digital Sky Survey (SDSS) spectroscopic database. The candidates are primarily selected to have quasi-featureless optical spectra and low…
We present the analysis of archival data from ROSAT and ASCA of a serendipitous source PKS 2316-423. According to its featureless non-thermal radio/optical continuum, the object has been assumed as a BL Lac candidate in the literature. It…
We explore the viability of the unification of BL Lacs and FR I radio galaxies by comparing the core emission of radio galaxies with those of BL Lacs, taking advantage of the newly measured optical nuclear luminosity of FR I sources. The…
We present a sample of 723 optically selected BL Lac candidates from the SDSS DR7 spectroscopic database encompassing 8250 deg^2 of sky; our sample constitutes one of the largest uniform BL Lac samples yet derived. Each BL Lac candidate has…
We investigate the environments of galaxies around BL Lac objects and FR I radiogalaxies, the alleged parent populations of misaligned sources. We compare the environment of a sample of 50 BL Lac objects at 0.1<z<0.33 with that of a sample…
TeV-emitting BL Lac type blazars represent the extreme end of the blazar population. They are characterized by relatively weak jets and radiatively inefficient accretion disks. Particles accelerated in these jets experience fewer radiative…
This paper considers the hypothesis that BL Lacertae objects (BLLs) are the beamed remnants of Quasi Stellar Objects. The hypothesis explains why BLLs do not undergo the strong evolution seen in other active galactic nuclei since it…
We investigate the properties of the host galaxies of X-ray selected (high frequency peaked) BL Lac objects using a large and homogeneous data set of high spatial resolution R-band observations of 52 BL Lacs in the EMSS and Slew samples.…
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…
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…
BL Lac objects are an elusive and rare class of active galactic nuclei. For years their evolutionary behavior has appeared inconsistent with the trend observed in the population of AGN at large. The so-called ``negative'' evolution implies…
High-resolution images of 7 newly identified BL Lac objects (among them one BL Lac candidate) at z < 0.2 from the Einstein Slew Survey are presented for the first time. In all cases we were able to resolve the host galaxy. Our 2-dimensional…
Aims. We aim to determine the redshift (or stringent lower limits) of a number of bright BL Lacs objects. Methods. We secured medium resolution optical and near-infrared spectra of 4 bright BL Lac objects of unknown redshift using the…
We present B-band imaging of 18 low redshift (z<0.3) BL Lac objects for which their host galaxies were previously resolved in the R-band and the near-infrared H-band. For a subset of the objects, also U- and V-band imaging is presented.…
Fermi has provided the largest sample of gamma-ray selected blazars to date. In this work we use a uniformly selected set of 211 BL Lacertae (BL Lac) objects detected by it Fermi during its first year of operation. We have obtained redshift…
We address the question of whether or not the properties of all low-luminosity flat spectrum radio sources, not just the obvious BL Lac objects, are consistent with them being the relativistically beamed counterparts of the low radio…