Related papers: VHE gamma-ray emission of PKS 2155-304: spectral a…
We apply both leptonic and leptohadronic emission scenarios for modelling the multiwavelength photon spectra and the observed variability in the optical, X-ray, and TeV gamma-ray energy bands of blazar PKS 2155-304 while being in a low…
The TeV blazar PKS 2155-304 was monitored with the X-ray satellite ASCA in 1994 May, as part of a multiwavelength campaign from the radio to X-ray bands. At the beginning of the two-day continuous observation, we detected a large flare,…
The close X-ray selected BL Lac PKS 2155-304 has been observed using the University of Durham Mark 6 very high energy (VHE) gamma ray telescope during 1996 September/October/November and 1997 October/November. VHE gamma rays with energy >…
We present results of variability study of a sample of 20 powerful blazars using Fermi/LAT (0.1--300 GeV) observations. We studied decade-long observations applying various analysis tools such as flux distribution, symmetry analysis, and…
We report radio imaging and monitoring observations in the frequency range 0.235 - 2.7 GHz during the flaring mode of PKS 2155-304, one of the brightest BL Lac objects. The high sensitivity GMRT observations not only reveal extended…
Gamma-ray emitting blazars have been the targets of many recent or ongoing monitoring programmes. The resulting multi-wavelength data archives are ideal for studying the quiescent and variable behaviour of the blazar PKS 2155-304. Here,…
We present a comprehensive 20-year multiwavelength variability study of the blazar PKS 2155-304, one of the most luminous and extensively monitored high-frequency-peaked BL Lac objects in the southern hemisphere. Using Fermi-LAT…
In this paper we report on the analysis of all the available optical and very high-energy $\gamma$-ray ($>$200 GeV) data for the BL Lac object PKS 2155$-$304, collected simultaneously with the ATOM and H.E.S.S. telescopes from 2007 until…
With currently available XMM-Newton EPIC pn observations spanned over about 3 years, we present a detailed spectral and temporal variability of the 0.2--10 keV X-ray emission from the X-ray bright BL Lac object PKS 2155-304. The spectral…
Blazars, a subclass of active galactic nuclei (AGN), are known to be bright $\gamma$-ray sources, frequently exhibiting active (flaring) periods. The blazar PKS~2155-304 is a high synchrotron-peaked BL Lac object located at redshift…
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…
PKS 1510-089 (z=0.361) is one of only a handful of flat spectrum radio quasars that have been detected at very high energy (VHE, $E>100\,$GeV) gamma rays. It is a very active source across the entire electromagnetic spectrum. VHE…
The low-frequency peaked BL Lac (LBL) object BL Lacertae was observed with the MAGIC telescope from 2005 August to December (22.2 hr), and from 2006 July to September (26.0 hr). A very high energy (VHE) gamma-ray signal was discovered with…
The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies, providing new opportunities for studies of Active Galactic Nuclei (AGNs) with soft intrinsic spectra and at high…
We have analyzed XMM-Newton observations of the high energy peaked blazar, PKS 2155-304, made on 24 May 2002 in the 0.3 - 10 keV X-ray band. These observations display a mini-flare, a nearly constant flux period and a strong flux increase.…
Optical, near-infrared, and radio observations of the BL Lac object PKS2155-304 were obtained simultaneously with a continuous UV/EUV/X-ray monitoring campaign in 1994 May. Further optical observations were gathered throughout most of 1994.…
We have performed an optical observation campaign on PKS 2155-304, whose aim was to determine the variability properties of this object on very short time scales in several photometric bands. We detected variability on time scales as short…
Spectral variability is the main tool for constraining emission models of BL Lac objects. By means of systematic observations of the BL Lac prototype PKS 2155-304 in the infrared-optical band, we explore variability on the scales of months,…
The blazar 1ES 1101-232 was observed with the High Energy Stereoscopic System (H.E.S.S.) of Atmospheric Cherenkov Telescopes (ACT) in 2004 and 2005, for a live time of 43 hours. VHE (E > 10^11 eV) gamma-rays were detected for the first time…
The MAGIC collaboration observed BL Lacertae for 22.2 hr during 2005 August to December and for 26 hr during 2006 July to September. The source is the historical prototype and eponym of a class of low-frequency peaked BL Lacertae (LBL)…