Journal article
VERITAS Observations of the Galactic Center Region at Multi-TeV Gamma-Ray Energies
The Astrophysical journal, v 913(2), p115
01 Jun 2021
Abstract
The Galactic Center (GC) region hosts a variety of powerful astronomical sources and rare astrophysical processes that emit a large flux of nonthermal radiation. The inner 375 pc x 600 pc region, called the Central Molecular Zone, is home to the supermassive black hole Sagittarius A*, massive cloud complexes, and particle accelerators such as supernova remnants (SNRs). We present the results of our improved analysis of the very-high-energy gamma-ray emission above 2 TeV from the GC using 125 hr of data taken with the Very Energetic Radiation Imaging Telescope Array System imaging-atmospheric Cerenkov telescope between 2010 and 2018. The central source VER J1745-290, consistent with the position of Sagittarius A*, is detected at a significance of 38 standard deviations above the background level (38 sigma), and we report its spectrum and light curve. Its differential spectrum is consistent with a power law with exponential cutoff, with a spectral index of spectral index of 2.12(-0.17)(+0.22), a flux normalization at 5.3 TeV of 1.27(-0.23)(+0.22) x 10(-13) TeV-1 cm(-2) s(-1), and cutoff energy of 10.0(-2.0)(+4.0) TeV. We also present results on the diffuse emission near the GC, obtained by combining data from multiple regions along the GC ridge, which yield a cumulative significance of 9.5 sigma. The diffuse GC ridge spectrum is best fit by a power law with a hard index of 2.19 +/- 0.20, showing no evidence of a cutoff up to 40 TeV. This strengthens the evidence for a potential accelerator of PeV cosmic rays being present in the GC. We also provide spectra of the other sources in our field of view with significant detections, composite SNR G0.9+0.1, and HESS J1746-285.
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Details
- Title
- VERITAS Observations of the Galactic Center Region at Multi-TeV Gamma-Ray Energies
- Creators
- C. B. Adams - Barnard CollegeW. Benbow - Center for Astrophysics Harvard & SmithsonianA. Brill - Columbia UniversityR. Brose - University of PotsdamM. Buchovecky - University of California, Los AngelesM. Capasso - Barnard CollegeJ. L. Christiansen - California Polytechnic State UniversityA. J. Chromey - Iowa State UniversityM. K. Daniel - Center for Astrophysics Harvard & SmithsonianM. Errando - Washington University in St. LouisA. Falcone - Pennsylvania State UniversityQ. Feng - Barnard CollegeJ. P. Finley - Purdue University West LafayetteL. Fortson - University of MinnesotaA. Furniss - California State University, East BayA. Gent - Georgia Institute of TechnologyG. H. Gillanders - Ollscoil na Gaillimhe – University of GalwayC. Giuri - DESY, Platanenallee 6, D-15738 Zeuthen, GermanyD. Hanna - McGill UniversityO. Hervet - University of California, Santa CruzJ. Holder - University of DelawareG. Hughes - Center for Astrophysics Harvard & SmithsonianT. B. Humensky - Columbia UniversityW. Jin - University of AlabamaP. Kaaret - University of IowaN. Kelley-Hoskins - DESY, Platanenallee 6, D-15738 Zeuthen, GermanyM. Kertzman - DePauw UniversityD. Kieda - University of UtahF. Krennrich - Iowa State UniversityS. Kumar - McGill UniversityM. J. Lang - Ollscoil na Gaillimhe – University of GalwayM. Lundy - McGill UniversityG. Maier - DESY, Platanenallee 6, D-15738 Zeuthen, GermanyP. Moriarty - Ollscoil na Gaillimhe – University of GalwayR. Mukherjee - Barnard CollegeD. Nieto - Universidad Complutense de MadridM. Nievas-Rosillo - DESY, Platanenallee 6, D-15738 Zeuthen, GermanyS. O'Brien - McGill UniversityR. A. Ong - University of California, Los AngelesA. N. Otte - Georgia Institute of TechnologyK. Pfrang - DESY, Platanenallee 6, D-15738 Zeuthen, GermanyM. Pohl - University of PotsdamR. R. Prado - DESY, Platanenallee 6, D-15738 Zeuthen, GermanyE. Pueschel - DESY, Platanenallee 6, D-15738 Zeuthen, GermanyJ. Quinn - University College DublinK. Ragan - McGill UniversityP. T. Reynolds - Munster Technological UniversityD. Ribeiro - Columbia UniversityG. T. Richards - University of DelawareE. Roache - Center for Astrophysics Harvard & SmithsonianJ. L. Ryan - University of California, Los AngelesM. Santander - University of AlabamaS. Schlenstedt - CTAO, Saupfercheckweg 1, D-69117 Heidelberg, GermanyG. H. Sembroski - Purdue University West LafayetteR. Shang - University of California, Los AngelesB. Stevenson - University of California, Los AngelesS. P. Wakely - Fermi National Accelerator LaboratoryA. Weinstein - Iowa State UniversityD. A. Williams - University of California, Santa Cruz
- Publication Details
- The Astrophysical journal, v 913(2), p115
- Publisher
- IOP Publishing Ltd
- Number of pages
- 11
- Grant note
- Helmholtz Association in Germany; Helmholtz Association NSERC in Canada; Natural Sciences and Engineering Research Council of Canada (NSERC) DE-AC02-05CH11231 / U.S. Department of Energy Office of Science User Facility; United States Department of Energy (DOE) U.S. Department of Energy Office of Science; United States Department of Energy (DOE) U.S. Department of Energy's Office of Science; United States Department of Energy (DOE) Smithsonian Institution PHY-1307171; PHY-1607491 / National Science Foundation; National Science Foundation (NSF) U.S. National Science Foundation; National Science Foundation (NSF)
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Physics
- Web of Science ID
- WOS:000657112700001
- Scopus ID
- 2-s2.0-85108159936
- Other Identifier
- 991021869041904721
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Astronomy & Astrophysics