Journal article
VERITAS OBSERVATIONS OF DAY-SCALE FLARING OF M 87 IN 2010 APRIL
The Astrophysical journal, Vol.746(2), 141
2012
DOI: 10.1088/0004-637X/746/2/141
Abstract
VERITAS has been monitoring the very-high-energy (VHE; > 100 GeV) gamma-ray activity of the radio galaxy M 87 since 2007. During 2008, flaring activity on a timescale of a few days was observed with a peak flux of (0.70 ± 0.16) × 10−11 cm−2 s−1 at energies above 350 GeV. In 2010 April, VERITAS detected a flare from M 87 with peak flux of (2.71 ± 0.68) × 10−11 cm−2 s−1 for E > 350 GeV. The source was observed for six consecutive nights during the flare, resulting in a total of 21 hr of good-quality data. The most rapid flux variation occurred on the trailing edge of the flare with an exponential flux decay time of 0.90+0.22−0.15 days. The shortest detected exponential rise time is three times as long, at 2.87+1.65−0.99 days. The quality of the data sample is such that spectral analysis can be performed for three periods: rising flux, peak flux, and falling flux. The spectra obtained are consistent with power-law forms. The spectral index at the peak of the flare is equal to 2.19 ± 0.07. There is some indication that the spectrum is softer in the falling phase of the flare than the peak phase, with a confidence level corresponding to 3.6 standard deviations. We discuss the implications of these results for the acceleration and cooling rates of VHE electrons in M 87 and the constraints they provide on the physical size of the emitting region.
Details
- Title: Subtitle
- VERITAS OBSERVATIONS OF DAY-SCALE FLARING OF M 87 IN 2010 APRIL
- Creators
- E Aliu - Columbia UniversityT Arlen - University of California, Los AngelesA 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 Aune - University of California, Santa CruzJ. P Finley - Purdue University West LafayetteG Finnegan - University of UtahL Fortson - University of MinnesotaA Furniss - University of California, Santa CruzN Galante - Harvard UniversityD Gall - University of IowaS Godambe - University of UtahS Griffin - McGill UniversityJ Grube - Adler PlanetariumR Guenette - McGill UniversityM Beilicke - Washington University in St. LouisG Gyuk - Adler PlanetariumD Hanna - McGill UniversityJ Holder - University of DelawareH Huan - University of ChicagoG Hughes - DESY, Platanenallee 6, 15738 Zeuthen, GermanyC. M Hui - University of UtahT. B Humensky - Columbia UniversityA Imran - Iowa State UniversityP Kaaret - University of IowaN Karlsson - University of MinnesotaW Benbow - Harvard UniversityM Kertzman - DePauw UniversityD 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 UtahA. S Madhavan - Iowa State UniversityG Maier - DESY, Platanenallee 6, 15738 Zeuthen, GermanyP Majumdar - University of California, Los AngelesS Mcarthur - Washington University in St. LouisA Bouvier - University of California, Santa CruzA Mccann - McGill UniversityP Moriarty - Galway-Mayo Institute of TechnologyR Mukherjee - Columbia UniversityP. D Nunez - University of UtahR. A Ong - University of California, Los AngelesM Orr - Iowa State UniversityA. N Otte - Georgia Institute of TechnologyN Park - University of ChicagoJ. S Perkins - University of Maryland, Baltimore CountyA Pichel - Barnard CollegeS. 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.746(2), 141
- DOI
- 10.1088/0004-637X/746/2/141
- ISSN
- 0004-637X
- eISSN
- 1538-4357
- Publisher
- Institute of Physics (IOP)
- Language
- English
- Date published
- 2012
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199725602771
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