Related papers: Infrared Variation of Blazars
We present the light curve data of a remarkable blazer 3C 454.3 (z=0.859) in optical, X-ray, and gamma-ray bands. Since January 2008, we have been monitoring this object using the 50 cm MITSuME, a optical telescope, and detected several…
Blazars are characterized by large amplitude and fast variability, indicating that the electron distribution is rapidly changing, often on time scales shorter than the light crossing time. We study the time dependent behavior of the…
Recent monitoring programs of ultra cool field M and L dwarfs (low mass stars or brown dwarfs) have uncovered low amplitude photometric I-band variations which may be associated with an inhomogeneous distribution of photospheric…
The high-frequency-peaked BL Lacertae object RGB J0710+591 was observed in the very high-energy (VHE; E > 100 GeV) wave band by the VERITAS array of atmospheric Cherenkov telescopes. The observations, taken between 2008 December and 2009…
We analyzed the multi-band optical behaviour of the BL Lacertae object, S5 0716+714, during its outburst state from 2014 November - 2015 March. We took data on 23 nights at three observatories, one in India and two in Bulgaria, making…
We present the results of an extensive analysis of the optical, ultraviolet, X-ray and $\gamma$-ray data collected from the observations of the BL Lac objects prototype BL Lacertae carried out over a period of nearly 13 years, between…
The multiwavelength spectra of blazars appear to be dominated by nonthermal emission from a relativistic jet oriented close to the line of sight. The recent detection of many blazars at gamma-ray energies strongly supports this scenario.…
We present the results of photometric observations of three TeV blazars, 3C 66A, S5 0954+658 and BL Lacertae, during the period 2013--2017. Our extensive observations were performed in a total of 360 nights which produced $\sim$6820 image…
We present the results of a multifrequency campaign on the high-redshift (z = 3.1) blazar PKS 0537-286. The source was observed at different epochs from 2006 to 2008 with INTEGRAL and Swift, and nearly simultaneously with ground-based…
Many quasi-simultaneous optical observations of 17 blazars are obtained from previous papers published over the last 19 years in order to investigate the spectral slope variability and understand the radiation mechanism of blazars. The…
The X-ray spectrum of extreme HBL type blazars is located in the synchrotron branch of the broadband spectral energy distribution (SED), at energies below the peak. A joint fit of the extrapolated X-ray spectra together with a host galaxy…
We report on multiwavelength observations of the blazar PKS 0537-441 (z = 0.896) obtained from microwaves through gamma rays by SMA, REM, ATOM, Swift and Fermi during 2008 August-2010 April. Strong variability has been observed in gamma…
We present an extensive study on the X-ray intraday variability of ten TeV-emitting high synchrotron peaked blazars (HBLs): 1ES 0229+200, 1ES 0414+009, PKS 0548-322, 1ES 1101-232, 1H 1219+301, H 1426+428, Mrk 501, 1ES 1959+650, PKS…
We present results of a multi-epoch intra-night optical monitoring of eleven blazars consisting of six BL Lac objects and five radio core-dominated quasars (CDQs). These densely sampled and sensitive R-band CCD observations, carried out…
We study the ensemble optical variability of 276 FSRQs and 86 BL Lacs in the Palomar-QUEST Survey with the goal of searching for common fluctuation properties, examining the range of behavior across the sample, and characterizing the…
We present results based on the observations of the blazar 3C 66A from 2005 November 06 to 2016 February 14 in the BVR and I broadbands using 1.2m telescope of the Mt. Abu InfraRed Observatory (MIRO). The source was observed on 160 nights…
The uncharted territory of the high-redshift ($z\gtrsim3$) Universe holds the key to understand the evolution of quasars. In an attempt to identify the most extreme members of the quasar population, i.e., blazars, we have carried out a…
Blazars with redshifts z<0.1 are likely candidates for detection at energies in the range 300 GeV - 50 TeV with Cerenkov telescopes and scintillator arrays. We present gamma-ray flux predictions for a sample of 15 nearby flat-spectrum radio…
Context: Being dominated by non-thermal emission from aligned relativistic jets, blazars allow us to elucidate the physics of extragalactic jets, and, ltimately, how the energy is extracted from the central black hole in radio-loud active…
Blazars research is one of the hot topics of contemporary extra-galactic astrophysics. That is because these sources are the most abundant type of extra-galactic gamma-ray sources and are suspected to play a central role in multi-messenger…