Related papers: The VERITAS Extragalactic Science Program

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)…

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 distribution of dark matter in the Galaxy, according to state-of-the-art simulations, shows not only a smooth halo component but also a rich substructure where a hierarchy of dark matter subhalos of different masses is found. We present…

Relativistic jets in AGN in general, and in blazars in particular, are the most energetic and among the most powerful astrophysical objects known so far. Their relativistic nature provides them with the ability to emit profusely at all…

The Cygnus region of the galaxy is one of the richest regions of gas and star formation and is the brightest region of diffuse GeV emission in the northern sky. VERITAS has conducted deep observations (approximately 300 hours) in the…

During moonlit nights, observations with ground-based Cherenkov telescopes at very high energies (VHE, $E>100$ GeV) are constrained since the photomultiplier tubes (PMTs) in the telescope camera are extremely sensitive to the background…

This White Paper explores advances in the study of Active Galaxies which will be enabled by new observing capabilities at MeV energies (hard X-rays to gamma-rays; 0.1-1000 MeV), with a focus on multi-wavelength synergies. This spectral…

Imaging Atmospheric Cherenkov Telescopes have long been viewed as potential light collectors to be used for long baseline optical intensity interferometry observations. Intensity interferometry, as implemented with Cherenkov telescopes, is…

We present a summary of the observation strategy of TANAMI (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry), a monitoring program to study the parsec-scale structure and dynamics of relativistic jets in active…

Radio and gamma-ray emission from active galactic nuclei (AGN) are thought to share a common origin, related to the ejection phenomena in the vicinity of supermassive black holes. Thanks to its sensitivity, surveying capability, and broad…

Following the great success of the current Imaging Atmospheric Cherenkov Telescopes, the next generation gamma-ray telescope arrays, Cherenkov Telescope Array (CTA), is being prepared. CTA will have an order of magnitude higher sensitivity…

Fast radio bursts are bright, unresolved and short flashes of radio emission originating from outside the Milky Way. The origin of these mysterious outbursts is unknown, but their high luminosity and short duration has prompted much…

The extragalactic gamma-ray sky is dominated by relativistic jets aligned to the observer's line of sight, i.e., blazars. A few of their misaligned counterparts, e.g., radio galaxies, are also detected with the Fermi-Large Area Telescope…

With the installation of a new 28-m diameter imaging atmospheric Cherenkov telescope in the middle of the array, the H.E.S.S. instrument has entered since 2012 into its Phase II. The fifth large-size telescope is particularly important to…

In any given 24-hour period, the Fermi-LAT detects photons with energies of order 100 GeV not associated with any known VHE emitter. The RA/Dec of these photons frequently falls into the field of view of VERITAS the following evening. A…

EGRET has detected 67 sources associated with active galactic nuclei. With the exception of radio galaxy Cen A, all are classified as belonging to the blazar class of active galactic nuclei. The cumulative exposure from multiple EGRET…

The Fermi Gamma-ray Space Telescope with its main instrument on-board, the Large Area Telescope (LAT), opened a new era in the study of high-energy emission from Active Galactic Nuclei (AGN). When combined with contemporaneous ground- and…

BL Lacertae is the prototype of the blazar subclass known as BL Lac type objects. BL Lacertae object itself is a low-frequency-peaked BL Lac(LBL). Very high energy (VHE) gamma ray emission from this source was discovered in 2005 by MAGIC…

Imaging atmospheric Cherenkov telescopes, such as the Very Energetic Radiation Imaging Tele-scope Array System (VERITAS), are uniquely suited to resolve the detailed morphology ofextended regions of gamma-ray emission. However, standard…

The Fermi Gamma-ray Space Telescope is producing the most detailed inventory of the gamma-ray sky to date. Despite tremendous achievements approximately 25% of all Fermi extragalactic sources in the Second Fermi LAT Catalogue (2FGL) are…