P Cogan

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VERITAS, the Very Energetic Radiation Imaging Telescope Array System, is an array of four 12 m diameter imaging atmospheric Cherenkov telescopes for gamma-ray astronomy above 100 GeV currently in operation in Arizona. The VERITAS Collaboration has developed VEGAS, the VERITAS Gamma-ray Analysis Suite, a data-analysis software package for the processing of(More)
VERITAS is an atmospheric Cherenkov telescope array designed to study astrophysical sources of very-high-energy gamma radiation. Located in southern Arizona, USA, the array consists of four 12 m-diameter imaging Cherenkov telescopes. All four telescopes have been deployed at the basecamp of the Whipple Observatory and began full operation in early 2007.(More)
The multiwavelength observation of the nearby radio galaxy M 87 provides a unique opportunity to study in detail processes occurring in Active Galactic Nuclei from radio waves to TeV γ-rays. Here we report the detection of γ-ray emission above 250 GeV from M 87 in spring 2007 with the VERITAS atmospheric Cherenkov telescope array and discuss its correlation(More)
We report the detection of very high-energy γ-ray emission from the intermediate-frequency-peaked BL Lacertae object W Comae (z = 0.102) by VERITAS, an array of four imaging atmospheric-Cherenkov telescopes. The source was observed between January and April 2008. A strong outburst of γ-ray emission was measured in the middle of March, lasting for only four(More)
VERITAS employs a 12m segmented mirror and pixellated photomultiplier tube camera to detect the brief pulse of Cherenkov radiation produced by the extensive air shower initiated by a cosmic high-energy gamma ray. The VERITAS data acquisition system consists of a 500 Mega-Sample-Per-Second custom-built flash ADC system, which samples the Cherenkov light(More)
The first of the four atmospheric Cherenkov telescopes of the VERITAS array has been in operation at the Mt. Hopkins base camp since January 2005. The telescope has met all specifications. We present here a description of the technical performance, including calibration details and a summary of a preliminary analysis of Crab Nebula observations. The(More)
The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 10(12) electron volts and are bright sources of very-high-energy (VHE) gamma-ray emission, it is not yet known where the VHE emission originates. Here we(More)
A 31-year-old veterinarian developed seizures, left hemiparesis, loss of memory, and behavioral disorders 5 months after intensive antirabies vaccination, the longest incubation period yet recorded. Computed tomographic scan revealed a right frontal contrastenhanced mass that extended to the left frontal lobe through the corpus callosum. Brain biopsy showed(More)
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 adequate seed photons. The presence of high-energy electrons is established from the location of the synrchrotron peak(More)
We report results from an intensive multi-wavelength monitoring campaign on the TeV blazar Mrk 421 over the period of 2003–2004. The source was observed simultaneously at TeV energies with the Whipple 10 m telescope and at X-ray energies with Rossi X-ray Timing Explorer (RXTE) during each clear night within the Whipple observing windows. Supporting(More)