Results 1 to 10 of about 277 (132)
Polarization microvariability of BL Lacertae objects [PDF]
Astronomy and Astrophysics, 2005 Fil: Andruchow, Ileana. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata. Instituto de Astrofisica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronomicas y Geofisicas.
I Andruchow, G E Romero, S A Cellone
exaly +3 more sources
Quasi-periodicities of BL Lacertae objects [PDF]
Astronomy and Astrophysics, 2018 We review the reports of possible year-long quasi-periodicities of BL Lac objects in the γ-ray and optical bands, and present a homogeneous time analysis of the light curves of PKS2155−304, PG1553+113, and BL Lac. Based on results from a survey covering the entire Fermi γ-ray sky we have estimated the fraction of possible quasi-periodic BL Lac objects.
Angela Sandrinelli +2 more
exaly +4 more sources
VHE observations of BL Lacertae objects: 1995–2000
New Astronomy Reviews, 2004 The results of observations of 29 BL Lacertae objects taken with the Whipple Observatory 10 m gamma-ray Telescope between 1995 and 2000 are presented.
exaly +3 more sources
Two-injection Scenario for the Hard X-Ray Excess Observed in Mrk 421
The Astrophysical Journal, 2023 An interesting result that was recently reported for Mrk 421 is the detection of a significant excess at hard X-ray energies, which could provide useful information to investigate particle acceleration and emission mechanisms in the relativistic jet ...
Wen Hu, Da-Hai Yan, Qiang-Lin Hu
doaj +1 more source
The Astrophysical Journal Supplement Series, 2023 This paper presents the results of a detailed X-ray timing and spectral analysis of Mrk 501, which are based mainly on the Swift data obtained during 2021 February–2022 December. The source showed strongly enhanced X-ray activity, characterized by a long-
B. Kapanadze, A. Gurchumelia, M. Aller
doaj +1 more source
An optical view of BL Lacertae objects [PDF]
The Astronomy and Astrophysics Review, 2014 44 pages, 21 figure, to appear in The Astronomy and Astrophysics ...
Falomo, Renato +2 more
openaire +2 more sources
BL Lacertae objects as an evolutionary population [PDF]
Symposium - International Astronomical Union, 1986 If the BL Lac Objects are active nuclei with a beamed component that is dominant when directed at us, their observed luminosity function must comprise a flat faint branch: N(L)dL ∝ L1+1/pdL with p=4.5 (Urry and Shafer 1984). If this is flatter than the LF NP(L) of the parent objects at equal observed L, then we expect the counts of BL Lacs to flatten ...
A. Cavaliere, E. Giallongo, F. Vagnetti
openaire +1 more source
ZBLLAC: A Spectroscopic Database of BL Lacertae Objects [PDF]
The Astrophysical Journal Supplement Series, 2020 Abstract This paper describes the database of optical spectra of BL Lacertae (BLL) objects (Z BLL objects) available at https://web.oapd.inaf.it/zbllac/. At present, it contains calibrated spectra for 295 BLL. For about 35% of them, we report a firm measure of redshift z, while for 35 sources we set a lower limit on z based on the ...
Marco Landoni +3 more
openaire +2 more sources
Gamma-ray Emission and Variability Processes in High-Energy-Peaked BL Lacertae Objects
Universe, 2023 BL Lac objects are active galactic nuclei notable for a beamed nonthermal radiation, which is generated in one of the relativistic jets forming a small angle to the observer’s line-of-sight.
Bidzina Kapanadze
doaj +1 more source
Radio Polarization of BL Lacertae Objects [PDF]
Publications of the Astronomical Society of Japan, 2006 In the present work, using the data base of the University of Michigan Radio Astronomy Observatory (UMRAO) at three radio frequencies (4.8 GHz, 8GHZ, and 14.5 GHz), we studied the polarization properties for 47 BL Lacertae objects: 38 radio selected BL Lac objects, 7 X-ray selected BL Lac objects, and two inter-middle objects (Mkn 421 and Mkn 501), and
Fan, Jun-Hui +8 more
openaire +2 more sources