Journal article
VERITAS OBSERVATIONS OF THE TeV BINARY LS I +61° 303 DURING 2008-2010
The Astrophysical journal, Vol.738(1), 3
2011
DOI: 10.1088/0004-637X/738/1/3
Abstract
We present the results of observations of the TeV binary LS I +61° 303 with the VERITAS telescope array between 2008 and 2010, at energies above 300 GeV. In the past, both ground-based gamma-ray telescopes VERITAS and MAGIC have reported detections of TeV emission near the apastron phases of the binary orbit. The observations presented here show no strong evidence for TeV emission during these orbital phases; however, during observations taken in late 2010, significant emission was detected from the source close to the phase of superior conjunction (much closer to periastron passage) at a 5.6 standard deviation (5.6σ) post-trials significance. In total, between 2008 October and 2010 December a total exposure of 64.5 hr was accumulated with VERITAS on LS I +61° 303, resulting in an excess at the 3.3σ significance level for constant emission over the entire integrated data set. The flux upper limits derived for emission during the previously reliably active TeV phases (i.e., close to apastron) are less than 5% of the Crab Nebula flux in the same energy range. This result stands in apparent contrast to previous observations by both MAGIC and VERITAS which detected the source during these phases at 10% of the Crab Nebula flux. During the two year span of observations, a large amount of X-ray data were also accrued on LS I +61° 303 by the Swift X-ray Telescope and the Rossi X-ray Timing Explorer Proportional Counter Array. We find no evidence for a correlation between emission in the X-ray and TeV regimes during 20 directly overlapping observations. We also comment on data obtained contemporaneously by the Fermi Large Area Telescope.
Details
- Title: Subtitle
- VERITAS OBSERVATIONS OF THE TeV BINARY LS I +61° 303 DURING 2008-2010
- Creators
- V. A Acciari - Harvard UniversityE Aliu - Columbia UniversityA Cannon - University College DublinA Cesarini - Ollscoil na Gaillimhe – University of GalwayL Ciupik - Adler PlanetariumE COLLINS-HUGHES - University College DublinM. P Connolly - Ollscoil na Gaillimhe – University of GalwayW Cui - Purdue University West LafayetteR Dickherber - Washington University in St. LouisC Duke - Grinnell CollegeM Errando - Columbia UniversityA Falcone - Pennsylvania State UniversityT Arlen - University of California, Los AngelesJ. P Finley - Purdue University West LafayetteG Finnegan - University of UtahL Fortson - University of MinnesotaA Furniss - University of California, Santa CruzN Gaeante - Center for Astrophysics Harvard & SmithsonianD Gall - Purdue University West LafayetteG. H Gillanders - Ollscoil na Gaillimhe – University of GalwayS Godambe - University of UtahS Griffin - McGill UniversityJ Grube - Adler PlanetariumT Aune - University of California, Santa CruzR Guenette - McGill UniversityG Gyuk - Adler PlanetariumD Hanna - McGill UniversityJ Holder - University of DelawareG Hughes - DESY, Platanenallee 6, 15738 Zeuthen, GermanyC. M Hui - University of UtahT. B Humensky - University of ChicagoP Kaaret - University of IowaN Karlsson - University of MinnesotaM Kertzman - DePauw UniversityM Beilicke - Washington University in St. LouisD Kieda - University of UtahH Krawczynski - Washington University in St. LouisF Krennrich - Iowa State UniversityM. J Lang - Ollscoil na Gaillimhe – University of GalwayS Lebohec - University of UtahG Maier - DESY, Platanenallee 6, 15738 Zeuthen, GermanyP Majumdar - University of California, Los AngelesS Mcarthur - Washington University in St. LouisA Mccann - McGill UniversityP Moriarty - Galway-Mayo Institute of TechnologyW Benbow - Harvard UniversityR Mukherjee - Columbia UniversityR. A Ong - University of California, Los AngelesM Orr - Iowa State UniversityA. N Otte - University of California, Santa CruzN Park - University of ChicagoJ. S Perkins - Harvard UniversityM Pohl - University of PotsdamH Prokoph - DESY, Platanenallee 6, 15738 Zeuthen, GermanyJ Quinn - University College DublinK Ragan - McGill UniversityS. M Bradbury - University of LeedsJ. H Buckley - Washington University in St. LouisV Bugaev - Washington University in St. LouisK Byrum - Argonne National Laboratory
- Resource Type
- Journal article
- Publication Details
- The Astrophysical journal, Vol.738(1), 3
- DOI
- 10.1088/0004-637X/738/1/3
- ISSN
- 0004-637X
- eISSN
- 1538-4357
- Publisher
- Institute of Physics (IOP)
- Language
- English
- Date published
- 2011
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199783502771
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