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We present results from a deep VERITAS exposure of the distant (z=0.89) flat-spectrum radio quasar (FSRQ) 4C +55.17. The high flux, hard index and steady emission found by Fermi LAT observations make this blazar a promising very-high-energy (VHE; E>100 GeV) candidate, offering a possibility to clarify the location of FSRQ VHE emission. Non-detection supports the hypothesis that any VHE gamma-rays are produced within and absorbed by the broad-line region while VHE detection would support an emission region outside the broad line region and far from the base of the jet. This FSRQ additionally provides the possible means, by photon-photon pair production, to constrain the currently available extragalactic background light (EBL) models out to the groundbreaking redshift of z=0.89. The log-parabolic model that is fitted to the LAT photons allows an extrapolation of the fit up to VHE while accounting for the gamma-ray absorption by the EBL. The VERITAS upper limit derived from the deep exposure is compared to this extrapolated VHE flux.
The bright gamma-ray quasar 4C +55.17 is a distant source ($z = 0.896$) with a hard spectrum at GeV energies as observed by the Large Area Telescope (LAT) on board the {{it Fermi}} satellite. This source is identified as a good source candidate for v
VERITAS is a state-of-the-art ground-based gamma-ray observatory that operates in the very high-energy (VHE) region of 100 GeV to 50 TeV. The observatory consists of an array of four 12m-diameter imaging atmospheric Cherenkov telescopes located in so
The object 4C 71.07 is a high-redshift blazar whose spectral energy distribution shows a prominent big blue bump and a strong Compton dominance. We present the results of a two-year multiwavelength campaign led by the Whole Earth Blazar Telescope (WE
A decade after the discovery of TeV gamma-rays from the blazar Mrk 421 (Punch et al. 1992), the list of TeV blazars has increased to five BL Lac objects: Mrk 421 (Punch et al. 1992; Petry et al. 1996; Piron et al. 2001), Mrk 501 (Quinn et al. 1996; A
Ground-based $gamma$-ray observatories, such as the VERITAS array of imaging atmospheric Cherenkov telescopes, provide insight into very-high-energy (VHE, $mathrm{E}>100,mathrm{GeV}$) astrophysical transient events. Examples include the evaporation o