Results 51 to 60 of about 1,386,746 (158)
Long-term Optical Spectroscopic Variability of BL Lacertae Object AO 0235+164
The Astrophysical JournalThe changing-look (CL) phenomenon in active galactic nuclei (AGNs) poses a significant challenge to the unified model. As a special subclass of AGN, blazars provide valuable insights.
W. T. He +3 more
doaj +1 more source
The Astrophysical Journal, 2023 The Fermi fourth catalog of active galactic nuclei (AGNs) data release 3 (4LAC-DR3) contains 3407 AGNs, out of which 755 are flat spectrum radio quasars (FSRQs), 1379 are BL Lacertae objects (BL Lac objects), 1208 are blazars of unknown (BCUs) type ...
A. Agarwal
doaj +1 more source
Flux and Spectral Variability of High-Energy-Peaked BL Lacertae Objects in the 0.3–10 keV Band
GalaxiesBL Lacertae objects (BL Lacs) are active galactic nuclei notable for beamed emission generated in the relativistic jets, forming a small angle with respect to our line-of-sight.
Bidzina Kapanadze
doaj +1 more source
Highly Polarized Optically Selected BL Lacertae Objects [PDF]
The Astrophysical Journal, 2007 9 pages, 3 figures, 2 ...
Smith, Paul S. +4 more
openaire +2 more sources
Rapid Optical Flares in the Blazar OJ 287 on Intraday Timescales with TESS
The Astrophysical Journal, 2023 We have analyzed the optical light curves of the blazar OJ 287 obtained with the Transiting Exoplanet Survey Satellite over about 80 days from 2021 October 13 to December 31, with an unprecedented sampling of 2 minutes.
Shubham Kishore +2 more
doaj +1 more source
On the Cosmological Evolution of BL Lacertae Objects
The Astrophysical Journal, 2002 We study the cosmological evolution of BL Lac objects by applying the Ve/Va analysis to a new sample of 55 objects, presented for the first time in this paper. This sample has been selected from the 239 sources with the brightest X-ray flux (≥4 × 10-13 ergs s-1 cm-2) and relatively bright optical counterparts (B ≤ 20.5) among the ~1600 objects included
A. Caccianiga +4 more
openaire +1 more source
BeppoSAX observations of 1-Jy BL Lacertae objects -- II [PDF]
Monthly Notices of the Royal Astronomical Society, 2004 We present new BeppoSAX LECS and MECS observations, covering the energy range 0.1 - 10 keV (observer's frame), of four BL Lacertae objects selected from the 1 Jy sample. All sources display a flat (alpha_x ~ 0.7) X-ray spectrum, which we interpret as inverse Compton emission.
PADOVANI P. +5 more
openaire +4 more sources
The optical polarization of BL Lacertae objects.
, 1990 We have used the optical polarization properties of BL Lacertae objects to gain insights into the range and physical causes of their extreme and spectacular observed properties. This dissertation consists of three parts.
Jannuzi, Buell Tomasson.
core +4 more sources
ROSAT Observations of BL Lacertae Objects
, 1996 We present soft X-ray spectra of 74 BL Lacertae objects observed with the PSPC detector on board of the ROSAT satellite. The sample contains all BL Lac objects detected during the pointed observation phase as a target or serendipitously. We have investigated the soft X-ray and broad band spectral properties and discuss the consequences for the X-ray ...
Lamer, G., Brunner, H., Staubert, R.
openaire +2 more sources
Classification of Fermi BCUs Using Machine Learning
The Astrophysical Journal, 2023 The Fermi Large Area Telescope (LAT) has detected 6659 γ -ray sources in the incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi-LAT catalog of γ -ray sources and 3743 of them are blazars, including 1517 blazar candidates of uncertain ...
Pei-yu Xiao +12 more
doaj +1 more source