A Very High Energy gamma-Ray Survey toward the Cygnus Region of the Galaxy


We present results from deep observations toward the Cygnus region using 300 hr of very high energy (VHE)gamma-ray data taken with the VERITAS Cerenkov telescope array and over 7 yr of high-energy.-ray data taken with the Fermi satellite at an energy above 1 GeV. As the brightest region of diffuse gamma-ray emission in the northern sky, the Cygnus region provides a promising area to probe the origins of cosmic rays. We report the identification of a potential Fermi-LAT counterpart to VER J2031+415 (TeV J2032+4130) and resolve the extended VHE source VER J2019+368 into two source candidates (VER J2018+367* and VER J2020+368*) and characterize their energy spectra. The Fermi-LAT morphology of 3FGL J2021.0+4031e (the Gamma Cygni supernova remnant) was examined, and a region of enhanced emission coincident with VER J2019+407 was identified and jointly fit with the VERITAS data. By modeling 3FGL J2015.6+3709 as two sources, one located at the location of the pulsar wind nebula CTB 87 and one at the quasar QSO J2015+371, a continuous spectrum from 1 GeV to 10 TeV was extracted for VER J2016+371 (CTB 87). An additional 71 locations coincident with Fermi-LAT sources and other potential objects of interest were tested for VHE gamma-ray emission, with no emission detected and upper limits on the differential flux placed at an average of 2.3% of the Crab Nebula flux. We interpret these observations in a multiwavelength context and present the most detailed gamma-ray view of the region to date.

acceleration of particles, cosmic rays, gamma rays: general, ISM: supernova remnants, SOURCE TEV J2032+4130, LARGE-AREA TELESCOPE, X-RAY, SOURCE TEV-J2032+4130, RADIO OBSERVATIONS, GALACTIC PLANE, COSMIC-RAYS, 4TH EDITION, FOLLOW-UP, CATALOG, Astronomy & Astrophysics
Abeysekara, A.U., et al. (2018): A Very High Energy γ-Ray Survey toward the Cygnus Region of the Galaxy. The Astrophysical Journal, 861(1). DOI: https://doi.org/10.3847/1538-4357/aac4a2