Related papers: Blazar Discoveries with VERITAS
All but three (M87, BL Lac and 3C 279) extragalactic sources detected so far at very high energy (VHE) gamma-rays belong to the class of high-frequency peaked BL Lac (HBL) objects. This suggested to us a systematic scan of candidate sources…
The high-frequency-peaked BL-Lacertae object \objectname{1ES 0806+524}, at redshift z=0.138, was observed in the very-high-energy (VHE) gamma-ray regime by VERITAS between November 2006 and April 2008. These data encompass the two-, and…
We report results from an intensive campaign of multiwavelength observations of the intermediate-frequency-peaked BL Lacertae object W Com (z=0.102) during a strong outburst of very high energy (VHE; E > 180 GeV) gamma-ray emission in June…
Here we present highlights from VERITAS observations of high-frequency-peaked BL Lac objects (HBLs). We discuss the key science motivations for observing these sources -- including performing multiwavelength campaigns critical to…
We conduct a search for periodic emission in the very high-energy gamma-ray band (VHE; E > 100 GeV) from a total of 13 pulsars in an archival VERITAS data set with a total exposure of over 450 hours. The set of pulsars includes many of the…
Observations of the blazars 1ES 0647+250 and 1ES 0806+524 with VERITAS are reported here. These objects are among the favoured candidate extragalactic sources in the very high-energy regime due to the presence of high-energy electrons and…
The Crab Nebula is the brightest source in the very-high-energy (VHE) gamma-ray sky and one of the best studied non-thermal objects. The dominant VHE emission mechanism is believed to be inverse Compton scattering of low energy photons on…
Active galactic nuclei are the most luminous persistent (non-transient, even if often variable) objects in the Universe. They are bright in the entire electromagnetic spectrum. Blazars are a special class where the jets point nearly to our…
Extreme high-energy peaked BL Lac objects (EHBLs) are a new emerging class of blazars. The typical two-hump structured spectral energy distribution (SED) is shifted to higher energies with respect to other more established classes of…
Very high-energy gamma-rays (VHE, E>100 GeV) propagating over cosmological distances can interact with the low-energy photons of the extragalactic background light (EBL) and produce electron-positron pairs. The transparency of the universe…
Extremely High energy peaked BL Lac (EHBL) objects are a special class of blazars with peculiar observational properties at X-ray and $\gamma$--ray energies. The observations of these sources indicate hard X-ray and $\gamma$--ray spectra…
VERITAS, the Very Energetic Radiation Telescope Imaging Array System, is an array of four imaging Atmospheric Cherenkov telescopes in southern Arizona. It is sensitive to gamma rays at energies above 100 GeV. Here, we discuss the results of…
RGB J2243+203 is a blazar at an estimated redshift of greater than 0.39 that has been classified both as an intermediate-frequency-peaked BL Lac object and as a high-frequency-peaked BL Lac object. This source has been detected by VERITAS…
The BL Lacertae object 1ES 1440+122 was observed in the energy range from 85 GeV to 30 TeV by the VERITAS array of imaging atmospheric Cherenkov telescopes. The observations, taken between 2008 May and 2010 June and totalling 53 hours,…
VERITAS is one of the world's most sensitive detectors of astrophysical VHE (E $>$ 100 GeV) gamma rays. This array of four 12-m imaging atmospheric-Cherenkov telescopes has operated for 12 years, and $>$6,000 hours of observations have been…
The emission of very-high-energy photons (VHE, E$>$100 GeV) in active galactic nuclei (AGN) is closely connected with the production of ultra-relativistic particles. Among AGN, the subclass of extreme BL Lacertae are of particular interest…
The extragalactic background light (EBL), a diffuse photon field in the optical and infrared range, is a record of radiative processes over the Universe's history. Spectral measurements of blazars at very high energies ($>$100 GeV) enable…
Blazars are radio-loud Active Galactic Nuclei (AGN) whose jets have a very small angle to our line of sight. Observationally, the radio emission are mostly compact or a compact-core with a 1-sided jet. With 2.5$^{\prime\prime}$ resolution…
We report on the VERITAS detection of very-high-energy (VHE, $E > 100~\mathrm{GeV}$) $\gamma$-ray emission from the optically bright quasar OJ 287 which is located at a redshift of z = 0.306. OJ 287 has been observed to display regular…
The highest-energy blazars exhibit non-thermal radiation extending beyond 1 TeV with high luminosities and strong variabilities, indicating extreme particle acceleration in their relativistic jets. The gamma-ray spectra of blazars contain…