TeV Gamma-Ray Observations of the Galactic Center Ridge by VERITAS
Pelassa, V.; Archer, A.; Benbow, W.; Bird, R.; Buchovecky, M.; Bugaev, V.; Falcone, A.; Feng, Q.; Finley, J. P.; Fleischhack, H.; Flinders, A.; Fortson, L.; Furniss, A.; Grube, J.; Hanna, D.; Holder, J.; Humensky, T. B.; Hütten, M.; Johnson, C. A.; Kaaret, P.; Kar, P.; Kelley-Hoskins, N.; Kertzman, M.; Kieda, D.; Krause, M.; Kumar, S.; Lang, M. J.; McArthur, S.; Moriarty, P.; Mukherjee, R.; Ong, R. A.; Park, N.; Pohl, M.; Popkow, A.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Richards, G. T.; Roache, E.; Rousselle, J.; Santander, M.; Sembroski, G. H.; Shahinyan, K.; Tyler, J.; Vassiliev, V. V.; Wakely, S. P.; Weinstein, A.; Wilhelm, A.; Williams, D. A.; Zitzer, B.; Chen, X.; Buckley, J. H.; Cardenzana, J. V.; Cerruti, M.; Ciupik, L.; Connolly, M. P.; Eisch, J. D.; Griffin, S.; Håkansson, N.; McCann, A.; Meagher, K.; Nieto, D.; Staszak, D.; Telezhinsky, I.; Tucci, J. V.; Yusef-Zadeh, F.; Collins-Hughes, E.; Gillanders, G. H.; Gyuk, G.; Krennrich, F.; Smith, A. W.; Millis, J.; Byrum, K.; Ratliff, G.; Weiner, O. M.
United States, Ireland, Germany, Canada
Abstract
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 VERITAS telescope array in the >2 TeV energy range. From these observations we (1) provide improved measurements of the differential energy spectrum for Sgr A* in the >2 TeV gamma-ray regime, (2) provide a detection in the >2 TeV gamma-ray emission from the composite SNR G0.9+0.1 and an improved determination of its multi-TeV gamma-ray energy spectrum, and (3) report on the detection of VER J1746-289, a localized enhancement of >2 TeV gamma-ray emission along the Galactic plane.