EVIDENCE FOR LONG-TERM GAMMA-RAY AND X-RAY VARIABILITY FROM THE UNIDENTIFIED TeV SOURCE HESS J0632+057

Acciari, V.; Aliu, E.; Arlen, T.; Beilicke, M.; Benbow, W.; Boltuch, D.; Bradbury, S.; Buckley, J.; Bugaev, V.; Byrum, K.; Cannon, A.; Cesarini, A.; Cesarini, A.; Chow, Y.; Ciupik, L.; Cogan, P.; Dickherber, R.; Duke, C.; Ergin, TÜLÜN; Falcone, A.; Fegan, S.; Finley, J.; Finnegan, G.; Fortin, P.; Fortson, L.; Furniss, A.; Gibbs, K.; Gillanders, G.; Grube, J.; Guenette, R.; Gyuk, G.; Hanna, D.; Holder, J.; Horan, D.; Hui, C.; Humensky, T.; Imran, A.; Kaaret, P.; Karlsson, N.; Kertzman, M.; Kieda, D.; Kildea, J.; Konopelko, A.; Krawczynski, H.; Krennrich, F.; Lang, M.; LeBohec, S.; LeBohec, S.; Maier, G.; McCann, A.; McCutcheon, M.; Millis, J.; Millis, J.; Moriarty, P.; Mukherjee, R.; Ong, R.; Otte, A.; Pandel, D.; Perkins, J.; Petry, D.; Pohl, M.; Quinn, J.; Ragan, K.; Reyes, L.; Reynolds, P.; Rose, H.; Schroedter, M.; Sembroski, G.; Smith, A.; Steele, D.; Swordy, S.; Theiling, M.; Toner, J.; Varlotta, A.; Vassiliev, V.; Vincent, S.; Wagner, R.; Wakely, S.; Ward, J.; Weekes, T.; Weinstein, A.; Weisgarber, T.; Williams, D.; Wissel, S.; Wood, M.

doi:10.1088/0004-637x/698/2/l94

EVIDENCE FOR LONG-TERM GAMMA-RAY AND X-RAY VARIABILITY FROM THE UNIDENTIFIED TeV SOURCE HESS J0632+057

Copy For Citation

Acciari V. A., Aliu E., Arlen T., Beilicke M., Benbow W., Boltuch D., ...More

ASTROPHYSICAL JOURNAL LETTERS, vol.698, no.2, 2009 (SCI-Expanded)

Publication Type: Article / Article
Volume: 698 Issue: 2
Publication Date: 2009
Doi Number: 10.1088/0004-637x/698/2/l94
Journal Name: ASTROPHYSICAL JOURNAL LETTERS
Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
Keywords: acceleration of particles, binaries: general, gamma rays: observations, stars: individual (HESS J0632+057, MWC 148), DISCOVERY, EMISSION
Middle East Technical University Affiliated: No

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 hr 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 nondetection by VERITAS excludes with a probability of 99.993% that HESS J0632+057 is a steady gamma-ray emitter. Contemporaneous X-ray observations with the Swift X-Ray Telescope 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 object as a gamma-ray emitting binary.