Related papers: VHE Observations of Galactic binary systems with V…
Gamma-ray binaries are variable sources of GeV-to-TeV photons with the peak in their spectral energy distributions above 100 MeV. There are only five Galactic gamma-ray binaries known and the processes which govern particle acceleration,…
Non-thermal variable emission from radio to very-high energy gamma rays (VHE; >100 GeV) are the prime characteristics of gamma-ray binaries. The underlying physical processes leading to the observed VHE emission are not well understood, as…
Since the commissioning of the array in Spring 2007, the VERITAS array (sensitive in the 0.1-50 TeV energy range) has acquired over 300 hours of observations investigating the TeV emission from X-ray binary star systems, in particular…
The high-mass X-ray binary system LS I +61 303 is well known as a rare example of a variable Galactic GeV and TeV gamma-ray emitter. Despite years of study, many aspects of the system remain unclear; the nature of the compact object, the…
X-ray binaries stand as the brightest X-ray sources in the galaxy, showing both variable X-ray emission and extreme flares. Some of these systems have been recently discovered to be TeV gamma-ray emitters, with the high energy emission…
We report on VERITAS observations at energies above 200 GeV of known or potential galactic gamma-ray sources. The observed objects comprise pulsars, pulsar wind nebulae, high-mass X-ray binaries and gamma-ray sources with unknown…
Gamma-ray blazars are among the most extreme astrophysical sources, harboring phenomena far more energetic than those attainable by terrestrial accelerators. These galaxies are understood to be active galactic nuclei that are powered by…
VERITAS (Very Energetic Radiation Imaging Telescope Array System) is one of the most sensitive currently operating arrays of imaging atmospheric Cherenkov telescopes, which detect very high-energy (VHE; E > 100 GeV) gamma rays. VERITAS is…
HESS J0632+057 has been recently identified as a new gamma-ray binary system. The source, located in the Monoceros region and associated with the massive Be star MWC 148, shows variability from radio to very high energy (VHE) gamma-rays,…
LS I +61 303 is one of only a few high-mass X-ray binaries currently detected at high significance in very high energy gamma-rays. The system was observed over several orbital cycles (between September 2006 and February 2007) with the…
The discovery of very high energy (VHE) gamma-ray emitting X-ray binaries has triggered an intense effort to better understand the particle acceleration, absorption, and emission mechanisms in compact binary systems, which provide variable…
The Be/X-ray binary system LS V +44 17 (RX J0440.9+4431) is a potential member of the rare class of gamma-ray binaries. The system is comprised of a Be star and a neutron star companion with an orbital period of 150 days. In December of…
Several binary systems, composed of a star and a compact object, have been detected in the GeV-TeV range. Several systems have been observed but only a handful of sources have shown emission at those energies. Here, we present the…
The population of binary systems known to emit in the GeV and TeV bands consists of only a few firmly identified Galactic sources. These rare objects constitute extreme particle accelerators operating under varying, but regularly repeating,…
HESS J0632+057 is an unidentified gamma-ray source located in the Monoceros region, probably associated with the massive Be star MWC 148. H.E.S.S. and VERITAS observations in the very high energy (VHE) range combined with Swift X-ray data…
The very-high-energy (VHE; E > 100 GeV) gamma-ray experiment, VERITAS, detected exceptionally bright flares from the high-mass X-ray binary LS I +61$^\circ$ 303 during the period October-December 2014. LS I +61$^\circ$ 303 is a known VHE…
HESS J0632+057 is one of only two unidentified high energy gamma-ray sources which appear to be point-like in nature. It is possibly associated with the massive star MWC 148 and has been suggested to resemble known TeV binary systems like…
Re-observations with the H.E.S.S. telescope array of the very-high-energy (VHE) source HESS J1018-589 A coincident with the Fermi-LAT $\gamma$-ray binary 1FGL J1018.6-5856 have resulted in a source detection significance of more than…
One of the most enigmatic TeV binary systems, LS I +61$^\circ$ 303 exhibits a high degree of flux modulation from radio to TeV wavelengths over a single orbit of the binary system, once every $\sim$26.5 days. The binary system also exhibits…
We present long-term observations of several VHE (E > 100 GeV) blazars with VERITAS, together with contemporaneous Swift and RXTE X-ray data. The observed targets include Mrk 421, Mrk 501, 1ES 2344+514. Strong flux and spectral variability…