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Title: Long-term TeV and X-ray observations of the gamma-ray binary HESS J0632+057

Abstract

HESS J0632+057 is the only gamma-ray binary known so far whose position in the sky allows observations with ground-based observatories in both the northern and southern hemispheres. Here we report on long-term observations of HESS J0632+057 conducted with the Very Energetic Radiation Imaging Telescope Array System and High Energy Stereoscopic System Cherenkov telescopes and the X-ray satellite Swift, spanning a time range from 2004 to 2012 and covering most of the system's orbit. The very-high-energy (VHE) emission is found to be variable and is correlated with that at X-ray energies. An orbital period of 315{sub −4}{sup +6} days is derived from the X-ray data set, which is compatible with previous results, P = (321 ± 5) days. The VHE light curve shows a distinct maximum at orbital phases close to 0.3, or about 100 days after periastron passage, which coincides with the periodic enhancement of the X-ray emission. Furthermore, the analysis of the TeV data shows for the first time a statistically significant (>6.5σ) detection at orbital phases 0.6-0.9. The obtained gamma-ray and X-ray light curves and the correlation of the source emission at these two energy bands are discussed in the context of the recent ephemeris obtained for themore » system. Our results are compared to those reported for other gamma-ray binaries.« less

Authors:
;  [1];  [2];  [3]; ;  [4]; ; ;  [5]; ;  [6];  [7];  [8];  [9];  [10];  [11];  [12];  [13];  [14];
  1. Department of Physics and Astronomy, Barnard College, Columbia University, New York, NY 10027 (United States)
  2. Physics Department, McGill University, Montreal, QC H3A 2T8 (Canada)
  3. Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)
  4. DESY, Platanenallee 6, D-15738 Zeuthen (Germany)
  5. Department of Physics, Washington University, St. Louis, MO 63130 (United States)
  6. Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States)
  7. Department of Physics and Astronomy and the Bartol Research Institute, University of Delaware, Newark, DE 19716 (United States)
  8. School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)
  9. Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States)
  10. Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States)
  11. Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States)
  12. School of Physics, National University of Ireland Galway, University Road, Galway (Ireland)
  13. Department of Physics, Purdue University, West Lafayette, IN 47907 (United States)
  14. Department of Physics, Grinnell College, Grinnell, IA 50112-1690 (United States)
Publication Date:
OSTI Identifier:
22348234
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 780; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; BINARY STARS; CHERENKOV COUNTERS; COMPARATIVE EVALUATIONS; CORRELATIONS; DETECTION; EMISSION; GAMMA RADIATION; ORBITS; SATELLITES; SKY; SOUTHERN HEMISPHERE; TELESCOPES; TEV RANGE; VISIBLE RADIATION; X RADIATION

Citation Formats

Aliu, E., Errando, M., Archambault, S., Aune, T., Behera, B., Chen, X., Beilicke, M., Buckley, J. H., Bugaev, V., Benbow, W., Cerruti, M., Berger, K., Bird, R., Bouvier, A., Byrum, K., Ciupik, L., Connolly, M. P., Cui, W., Duke, C., Dumm, J., E-mail: gernot.maier@desy.de, E-mail: afalcone@astro.psu.edu, E-mail: pol.bordas@uni-tuebingen.de, Collaboration: VERITAS Collaboration, H.E.S.S. Collaboration, and others, and. Long-term TeV and X-ray observations of the gamma-ray binary HESS J0632+057. United States: N. p., 2014. Web. doi:10.1088/0004-637X/780/2/168.
Aliu, E., Errando, M., Archambault, S., Aune, T., Behera, B., Chen, X., Beilicke, M., Buckley, J. H., Bugaev, V., Benbow, W., Cerruti, M., Berger, K., Bird, R., Bouvier, A., Byrum, K., Ciupik, L., Connolly, M. P., Cui, W., Duke, C., Dumm, J., E-mail: gernot.maier@desy.de, E-mail: afalcone@astro.psu.edu, E-mail: pol.bordas@uni-tuebingen.de, Collaboration: VERITAS Collaboration, H.E.S.S. Collaboration, & others, and. Long-term TeV and X-ray observations of the gamma-ray binary HESS J0632+057. United States. doi:10.1088/0004-637X/780/2/168.
Aliu, E., Errando, M., Archambault, S., Aune, T., Behera, B., Chen, X., Beilicke, M., Buckley, J. H., Bugaev, V., Benbow, W., Cerruti, M., Berger, K., Bird, R., Bouvier, A., Byrum, K., Ciupik, L., Connolly, M. P., Cui, W., Duke, C., Dumm, J., E-mail: gernot.maier@desy.de, E-mail: afalcone@astro.psu.edu, E-mail: pol.bordas@uni-tuebingen.de, Collaboration: VERITAS Collaboration, H.E.S.S. Collaboration, and others, and. Fri . "Long-term TeV and X-ray observations of the gamma-ray binary HESS J0632+057". United States. doi:10.1088/0004-637X/780/2/168.
@article{osti_22348234,
title = {Long-term TeV and X-ray observations of the gamma-ray binary HESS J0632+057},
author = {Aliu, E. and Errando, M. and Archambault, S. and Aune, T. and Behera, B. and Chen, X. and Beilicke, M. and Buckley, J. H. and Bugaev, V. and Benbow, W. and Cerruti, M. and Berger, K. and Bird, R. and Bouvier, A. and Byrum, K. and Ciupik, L. and Connolly, M. P. and Cui, W. and Duke, C. and Dumm, J., E-mail: gernot.maier@desy.de, E-mail: afalcone@astro.psu.edu, E-mail: pol.bordas@uni-tuebingen.de and Collaboration: VERITAS Collaboration and H.E.S.S. Collaboration and others, and},
abstractNote = {HESS J0632+057 is the only gamma-ray binary known so far whose position in the sky allows observations with ground-based observatories in both the northern and southern hemispheres. Here we report on long-term observations of HESS J0632+057 conducted with the Very Energetic Radiation Imaging Telescope Array System and High Energy Stereoscopic System Cherenkov telescopes and the X-ray satellite Swift, spanning a time range from 2004 to 2012 and covering most of the system's orbit. The very-high-energy (VHE) emission is found to be variable and is correlated with that at X-ray energies. An orbital period of 315{sub −4}{sup +6} days is derived from the X-ray data set, which is compatible with previous results, P = (321 ± 5) days. The VHE light curve shows a distinct maximum at orbital phases close to 0.3, or about 100 days after periastron passage, which coincides with the periodic enhancement of the X-ray emission. Furthermore, the analysis of the TeV data shows for the first time a statistically significant (>6.5σ) detection at orbital phases 0.6-0.9. The obtained gamma-ray and X-ray light curves and the correlation of the source emission at these two energy bands are discussed in the context of the recent ephemeris obtained for the system. Our results are compared to those reported for other gamma-ray binaries.},
doi = {10.1088/0004-637X/780/2/168},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 780,
place = {United States},
year = {2014},
month = {1}
}