Related papers: VERITAS Observations of M 87 in 2011/2012
M87 is the first extragalactic source detected in the TeV range that is not a blazar. With the increasing performances of ground-based Cherenkov telescopes, we can now probe the variability in the gamma-ray flux at small timescales, thus…
The radio galaxy M87 is a variable very-high energy (VHE) gamma-ray source, exhibiting three major flares reported in 2005, 2008, and 2010. Despite extensive studies, the origin of the VHE gamma-ray emission is yet to be understood. In this…
Radio-loud active galactic nuclei (AGN) with their jets pointed close to our line of sight constitute the majority of extragalactic $\gamma$-ray sources and significantly contribute to the radiation observed in the even higher energy…
The widespread detection of synchrotron X-ray emission from the jets of low-power, nearby radio galaxies implies the presence of electrons at and above TeV energies. In this paper we explore the possibility that the TeV gamma-rays detected…
The TeV binary system \lsi has a compact object in an eccentric orbit around a Be star about 2 kpc from Earth. \lsi exhibits modulated gamma-ray emission around its 26.5 days orbit, mostly detectable at TeV energies around its apastron…
Active galactic nuclei with misaligned jets have been recently established as a class of high-energy gamma-ray sources. M87, a nearby representative of this class, shows fast TeV variability on timescales less than one day. We present…
VERITAS is an array of four imaging atmospheric Cherenkov telescopes that observes gamma-ray sources in the very high energy range (VHE, E>100 GeV). A large fraction of the known gamma-ray sources are of extragalactic origin and belong to…
The Cygnus region of the Galactic plane contains many known supernova remnants, pulsars, X-ray and GeV gamma-ray emitters which make it a prime candidate for a Very High Energy (VHE) gamma-ray survey in the Northern Hemisphere. The VERITAS…
The VERITAS array of four 12-m imaging atmospheric-Cherenkov telescopes began full-scale operations in 2007, and is one of the world's most sensitive detectors of astrophysical very high energy (VHE; E>100 GeV) gamma rays. Observations of…
Thanks to the Fermi gamma-ray satellite and the current Imaging Atmospheric Cherenkov Telescopes, radio galaxies have arisen as a new class of high- and very-high energy emitters. The favourable orientation of their jets makes radio…
VERITAS is an array of four imaging atmospheric Cherenkov telescopes near Tucson, Arizona and is one of the world's most sensitive detectors of very high energy (VHE: >100 GeV) gamma rays. The scientific reach of VERITAS covers the study of…
We report the detection of very high energy gamma-ray emission from the blazar S3 1227+25 (VER J1230+253) with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). VERITAS observations of the source were triggered by the…
The HAWC observatory recently published their second source catalog with 39 very high energy gamma-ray sources based on 507 days of exposure time. Among these, there were 16 sources that are more than one degree away from any known TeV…
Since the commissioning of the array in Spring 2007, the VERITAS array (sensitive in the 0.1-50 TeV energy range) has acquired over 300 hours of observations investigating the TeV emission from X-ray binary star systems, in particular…
Gamma-ray observations of the Galactic Center (GC) region provide some of the most sensitive measurements of annihilation signals from dark matter in the GeV-TeV mass range. We present the first results from 178 hours of VERITAS…
The existence of intrinsic obscuration of Fanaroff-Riley I objects is a controversial topic. M87, the nearest such object, is puzzling in that although it has very massive central black hole it has a relatively low luminosity, suggesting it…
Outbursts from gamma-ray quasars provide insights on the relativistic jets of active galactic nuclei and constraints on the diffuse radiation fields that fill the Universe. The detection of significant emission above 100 GeV from a distant…
The VERITAS gamma ray observatory (Amado, AZ, veritas.sao.arizona.edu) uses the Imaging Atmospheric Cherenkov Technique (IACT) to study sources of Very High Energy (VHE: E > 100 GeV) gamma rays. Key science results from the first three…
The nearby spiral galaxy M81 harbors in its core a Low-Luminosity AGN (LLAGN), and appears closely related to the more distant and powerful AGNs seen in quasars and radio galaxies. The intrinsic size of this object is unknown due to…
M87 hosts one of the closest jetted active galactic nucleus (AGN) to Earth. Thanks to its vicinity and to the large mass of is central black hole, M87 is the only source in which the jet can be directly imaged down to near-event horizon…