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Full-Text Articles in Stars, Interstellar Medium and the Galaxy

A Search For Very High-Energy Gamma Rays From The Missing Link Binary Pulsar J1023+0038 With Veritas, P. T. Reynolds, Et Al Nov 2016

A Search For Very High-Energy Gamma Rays From The Missing Link Binary Pulsar J1023+0038 With Veritas, P. T. Reynolds, Et Al

Physical Sciences Publications

The binary millisecond radio pulsar PSR J1023+0038 exhibits many characteristics similar to the gamma-ray binary system PSR B1259–63/LS 2883, making it an ideal candidate for the study of high-energy nonthermal emission. It has been the subject of multiwavelength campaigns following the disappearance of the pulsed radio emission in 2013 June, which revealed the appearance of an accretion disk around the neutron star. We present the results of very high energy (VHE) gamma-ray observations carried out by the Very Energetic Radiation Imaging Telescope Array System before and after this change of state. Searches for steady and pulsed emission of both data …


Very High Energy Observations Of The Binaries V 404 Cyg And 4u 0115+634 During Giant X-Ray Outbursts, P. T. Reynolds, Et Al Oct 2016

Very High Energy Observations Of The Binaries V 404 Cyg And 4u 0115+634 During Giant X-Ray Outbursts, P. T. Reynolds, Et Al

Physical Sciences Publications

Transient X-ray binaries produce major outbursts in which the X-ray flux can increase over the quiescent level by factors as large as 107. The low-mass X-ray binary V 404 Cyg and the high-mass system 4U 0115+634 underwent such major outbursts in 2015 June and October, respectively. We present here observations at energies above hundreds of GeV with the VERITAS observatory taken during some of the brightest X-ray activity ever observed from these systems. No gamma-ray emission has been detected by VERITAS in 2.5 hr of observations of the microquasar V 404 Cyg from 2015, June 20–21. The upper flux limits …


Tev Gamma-Ray Observations Of The Galactic Center Ridge By Veritas, P. T. Reynolds, Et Al Apr 2016

Tev Gamma-Ray Observations Of The Galactic Center Ridge By Veritas, P. T. Reynolds, Et Al

Physical Sciences Publications

The Galactic Center ridge has been observed extensively in the past by both GeV and TeV gamma-ray instruments revealing a wealth of structure, including a diffuse component and the point sources G0.9+0.1 (a composite supernova remnant) and Sgr A* (believed to be associated with the supermassive black hole located at the center of our Galaxy). Previous very high energy (VHE) gamma-ray observations with the H.E.S.S. experiment have also detected an extended TeV gamma-ray component along the Galactic plane in the >300 GeV gamma-ray regime. Here we report on observations of the Galactic Center ridge from 2010 to 2014 by the …


A Search For Brief Optical Flashes Associated With The Seti Target Kic 8462852, P. T. Reynolds, Et Al Feb 2016

A Search For Brief Optical Flashes Associated With The Seti Target Kic 8462852, P. T. Reynolds, Et Al

Physical Sciences Publications

The F-type star KIC 8462852 has recently been identified as an exceptional target for search for extraterrestrial intelligence (SETI) observations. We describe an analysis methodology for optical SETI, which we have used to analyze nine hours of serendipitous archival observations of KIC 8462852 made with the VERITAS gamma-ray observatory between 2009 and 2015. No evidence of pulsed optical beacons, above a pulse intensity at the Earth of approximately , is found. We also discuss the potential use of imaging atmospheric Cherenkov telescope arrays in searching for extremely short duration optical transients in general.


Exceptionally Bright Tev Flares From The Binary Ls I+61 Degrees 303, P. T. Reynolds, Et Al Jan 2016

Exceptionally Bright Tev Flares From The Binary Ls I+61 Degrees 303, P. T. Reynolds, Et Al

Physical Sciences Publications

The TeV binary system LS I +61° 303 is known for its regular, non-thermal emission pattern that traces the orbital period of the compact object in its 26.5 day orbit around its B0 Ve star companion. The system typically presents elevated TeV emission around apastron passage with flux levels between 5% and 15% of the steady flux from the Crab Nebula (>300 GeV). In this article, VERITAS observations of LS I +61° 303 taken in late 2014 are presented, during which bright TeV flares around apastron at flux levels peaking above 30% of the Crab Nebula flux were detected. …