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.
| Original language | English (Ireland) |
|---|---|
| Pages (from-to) | L94-L97 |
| Number of pages | 4 |
| Journal | ASTROPHYSICAL JOURNAL LETTERS |
| Volume | 698 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 1 Jun 2009 |
Keywords
- Acceleration of particles
- Binaries: general
- Gamma rays: observations
Authors (Note for portal: view the doc link for the full list of authors)
- Authors
- Acciari, VA,Aliu, E,Arlen, T,Beilicke, M,Benbow, W,Boltuch, D,Bradbury, SM,Buckley, JH,Bugaev, V,Byrum, K,Cannon, A,Cesarini, A,Cesarini, A,Chow, YC,Ciupik, L,Cogan, P,Dickherber, R,Duke, C,Ergin, T,Falcone, A,Fegan, SJ,Finley, JP,Finnegan, G,Fortin, P,Fortson, L,Furniss, A,Gibbs, K,Gillanders, GH,Grube, J,Guenette, R,Gyuk, G,Hanna, D,Holder, J,Horan, D,Hui, CM,Humensky, TB,Imran, A,Kaaret, P,Karlsson, N,Kertzman, M,Kieda, D,Kildea, J,Konopelko, A,Krawczynski, H,Krennrich, F,Lang, MJ,LeBohec, S,LeBohec, S,Maier, G,McCann, A,McCutcheon, M,Millis, J,Millis, J,Moriarty, P,Mukherjee, R,Ong, RA,Otte, AN,Pandel, D,Perkins, JS,Petry, D,Pohl, M,Quinn, J,Ragan, K,Reyes, LC,Reynolds, PT,Rose, HJ,Schroedter, M,Sembroski, GH,Smith, AW,Steele, D,Swordy, S,Theiling, M,Toner, JA,Varlotta, A,Vassiliev, V