Related papers: Recent Highlights from the VERITAS AGN Discovery P…
During the 2007/2008 season, VERITAS was used for observations at E>200 GeV of several extragalactic non-blazar objects such as galaxy clusters, starburst and interacting galaxies, dwarf galaxies, and nearby galaxies. In these proceedings,…
After more than six and half years in orbit, the ESA space observatory INTEGRAL has provided new, exciting results in the soft gamma-ray energy range (from a few keV to a few MeV). With the discovery of about 700 hard X-Ray sources, it has…
The F-GAMMA-project is the coordinated effort of several observatories to understand the AGN phenomenon and specifically blazars via multi-frequency monitoring in collaboration with the {\sl Fermi}-GST satellite since January 2007. The core…
The density-based clustering algorithm DBSCAN has been applied to the Fermi Large Area Telescope (LAT) dataset of $ E_{\gamma} \geqslant 100$ GeV events with $\lvert b\rvert>10^{\circ}$, in order to search for new very high energy (VHE)…
The analysis of the variability of active galactic nuclei (AGNs) at different wavelengths and the study of possible correlations among different spectral windows are nowadays a major field of inquiry. Optical variability has been largely…
The VERITAS collaboration has approved long-term observations on several distant, hard-spectrum blazars. We present first results from VERITAS long-term observations of 1ES1218+304, 1ES0229+200, and 1ES0414+009. Gamma-ray observations of…
We present new results from the VLBA 2 cm Survey, an imaging survey of active galactic nuclei (AGN) at sub-milliarcsecond resolution. We extend the structural variability monitoring program of more than 130 extragalactic parsec-scale radio…
Clusters of galaxies are one of the few prominent classes of objects predicted to emit gamma rays not yet detected by satellites like EGRET or ground-based Imaging Atmospheric Cherenkov Telescopes (IACTs). The detection of Very High Energy…
We report on VERITAS observations at energies above 200 GeV of known or potential galactic gamma-ray sources. The observed objects comprise pulsars, pulsar wind nebulae, high-mass X-ray binaries and gamma-ray sources with unknown…
The giant radio galaxy M 87 is located at a distance of ~16 Mpc and harbors a supermassive black hole in its center. The structure of its relativistic plasma jet is resolved at radio, optical and X-ray wavelengths. M 87 belongs to the class…
The understanding of acceleration mechanisms in active galactic nuclei (AGN) jets and the measurement of the extragalactic-background-light (EBL) density are closely linked and require the detection of a large sample of very-high-energy…
The VERITAS collaboration reports the detection of very-high-energy (VHE) gamma-ray emission from the high-frequency-peaked BL Lac object 1ES 1218+304 located at a redshift of z=0.182. A gamma-ray signal was detected with high statistical…
We report on the VERITAS discovery of very-high-energy (VHE) gamma- ray emission above 200 GeV from the high-frequency-peaked BL Lac object RXJ0648.7+1516 (GBJ0648+1516), associated with 1FGLJ0648.8+1516. The photon spectrum above 200 GeV…
The Be/X-ray binary system LS V +44 17 (RX J0440.9+4431) is a potential member of the rare class of gamma-ray binaries. The system is comprised of a Be star and a neutron star companion with an orbital period of 150 days. In December of…
The detection of very-high-energy (VHE; $>$100 GeV) $\gamma$-ray radiation from misaligned jetted Active Galactic Nuclei (AGN) challenges the emission models that primarily explain VHE emissions from beamed AGN, i.e., blazars. Using over 16…
During the last year, six new Active Galactic Nuclei (AGN) have been discovered and studied by H.E.S.S. at Very High Energies (VHE). Some of these recent discoveries have been made thanks to new enhanced analysis methods and are presented…
The Very High Energy Gamma Ray Astronomy (VHE) is a rapidly evolving branch of modern astronomy, which covers the range from about 50 GeV to several tens of TeV from the ground. In the past years, the second generation instruments firmly…
Diffuse gamma rays are tracers of cosmic rays, providing information on their origin, interaction and diffusion through a galaxy. M 31 (the Andromeda Galaxy) is the closest spiral galaxy to the Milky Way (d = 780 kpc) and is very well…
This paper summarizes the status of very high-energy (VHE) astronomy, as of early 2003. It concentrates on observations made by gamma-ray telescopes operating at energies above 10 GeV. This field is an exciting one to be working in, with a…
We present the results of our search for highly variable active galactic nuclei (AGNs) the X-ray flux from which changed by more than an order of magnitude during the SRG/eROSITA all-sky survey. Using the eROSITA data obtained in the period…