Evidence for long-term Gamma-ray and X-ray variability from the unidentified TeV source HESS J0632+057

Abstract

HESS J0632+057 is one of only two unidentified very-high-energy gamma-ray sources which appear to be point-like within experimental resolution. It is possibly associated with the massive Be star MWC 148 and has been suggested to resemble known TeV binary systems like LS I +61 303 or LS 5039. HESS J0632+057 was observed by VERITAS for 31 hours in 2006, 2008 and 2009. During these observations, no significant signal in gamma rays with energies above 1 TeV was detected from the direction of HESS J0632+057. A flux upper limit corresponding to 1.1% of the flux of the Crab Nebula has been derived from the VERITAS data. The non-detection by VERITAS excludes with a probability of 99.993% that HESS J0632+057 is a steady gamma-ray emitter. Contemporaneous X-ray observations with Swift XRT reveal a factor of 1.8+-0.4 higher flux in the 1-10 keV range than earlier X-ray observations of HESS J0632+057. The variability in the gamma-ray and X-ray fluxes supports interpretation of the ob ject as a gamma-ray emitting binary.

8 pages, 3 figures, Accepted for publication in The Astrophysical Journal

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Cited by in corpus (35)

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• Long-term TeV and X-ray Observations of the Gamma-ray Binary HESS J0632+057
• TeV Gamma-ray Astronomy: A Summary
• Revealing the extended radio emission from the gamma-ray binary HESS J0632+057
• HD 259440: The Proposed Optical Counterpart of the gamma-ray Binary HESS J0632+057
• Discovery of variable VHE gamma-ray emission from the binary system 1FGL J1018.6-5856
• Search for TeV Gamma-Ray Emission from Point-like Sources in the Inner Galactic Plane with a Partial Configuration of the HAWC Observatory
• Swift, XMM-Newton, and NuSTAR observations of PSR J2032+4127/MT91 213
• Probing the Nature of the unidentified TeV Gamma-ray source HESS J0632+057 with Swift
• Binaries with the eyes of CTA
• Detection of VHE γ-rays from HESS J0632+057 during the 2011 February X-ray outburst with the MAGIC Telescopes
• Discovery of the VHE gamma-ray source HESS J1832-093 in the vicinity of SNR G22.7-0.2
• GeV detection of HESS J0632+057
• Observation of the gamma-ray binary HESS J0632+057 with the H.E.S.S., MAGIC, and VERITAS telescopes
• Gamma-ray observations of the Be/pulsar binary 1A 0535+262 during a giant X-ray outburst
• Optical spectroscopy of Be/gamma-ray binaries
• The TeV binary HESS J0632+057 in the low and high X-ray state
• The missing GeV γ-ray binary: Searching for HESS J0632+057 with Fermi-LAT
• Search for radio pulsations in LS I +61 303
• High energy gamma-ray emission from compact galactic sources in the context of observations with the next generation Cherenkov Telescope Arrays
• Fermi Large Area Telescope Observations of the Monoceros Loop Supernova Remnant
• Highlights from VERITAS on VHE Gamma-ray Sources in our Galaxy
• Probing the Properties of the Pulsar Wind in the Gamma-Ray Binary HESS J0632+057 with NuSTAR and VERITAS Observations
• Multi-Wavelength Observation Campaign of the TeV Gamma-Ray Binary HESS J0632+057 with NuSTAR, VERITAS, MDM, and Swift
• Orbital and superorbital variability of LS I +61 303 at low radio frequencies with GMRT and LOFAR
• Investigation of the broadband emission of the gamma-ray binary HESS J0632+057 using an intrabinary shock model
• Multi-wavelength observations of 2HWC J1928+177: dark accelerator or new TeV gamma-ray binary?
• Modeling the GeV emission of HESS J0632+057
• Highlight Talk: Recent Results from VERITAS
• A Decade of TeV Observations of the Gamma-ray Binary HESSJ0632+057 with VERITAS
• The Very Energetic Radiation Imaging Telescope Array System (VERITAS)
• The strange case of HESS J0632+057 and the γ-ray High Mass X-ray Binaries
• Cherenkov Telescope results on gamma-ray binaries
• Expected gamma-ray emission from x-ray binaries