"As one of the brightest active blazars in both X-ray and very high energy γ -ray bands, Mrk 501, is very useful for" "physics associated with jets from active galactic nuclei. The ARGO-YBJ experiment has monitored Mrk 501 for γ - rays above 0.3 TeV since 2007 November. The largest flare since 2005 was observed from 2011 October and lasted until about 2012 April. In this paper, a detailed analysis of this event is reported. During the brightest γ -ray flaring episodes from 2011 October 17 to November 22, an excess of the event rate over 6σ is detected by ARGO-YBJ in the direction of Mrk 501, corresponding to an increase of the γ -ray flux above 1 TeV by a factor of 6.6 ± 2.2 from its steady emission. In particular, the γ -ray flux above 8 TeV is detected with a significance better than 4σ . Based on time-dependent synchrotron self-Compton (SSC) processes, the broadband energy spectrum is interpreted as the emission from an electron energy distribution parameterized with a single power-law function with an exponential cutoff at its high-energy end. The average spectral energy distribution for the steady emission is well described by this simple one-zone SSC model. However, the detection of γ -rays above 8 TeV during the flare challenges this model due to the hardness of the spectra. Correlations between X-rays and γ -rays are also investigated."

B., B., 2, ., P., B., 4, ., X. J., B., C., B., et al. (2012). "LONG-TERM MONITORING OF MRK 501 FOR ITS VERY HIGH ENERGY" "γ EMISSION AND A FLARE IN 2011 OCTOBER". THE ASTROPHYSICAL JOURNAL, 758:2, 1-8 [10.1088/0004-637X/758/1/2].

"LONG-TERM MONITORING OF MRK 501 FOR ITS VERY HIGH ENERGY" "γ EMISSION AND A FLARE IN 2011 OCTOBER"

MARI, Stefano Maria;P. Montini8;F. Ruggieri8;
2012-01-01

Abstract

"As one of the brightest active blazars in both X-ray and very high energy γ -ray bands, Mrk 501, is very useful for" "physics associated with jets from active galactic nuclei. The ARGO-YBJ experiment has monitored Mrk 501 for γ - rays above 0.3 TeV since 2007 November. The largest flare since 2005 was observed from 2011 October and lasted until about 2012 April. In this paper, a detailed analysis of this event is reported. During the brightest γ -ray flaring episodes from 2011 October 17 to November 22, an excess of the event rate over 6σ is detected by ARGO-YBJ in the direction of Mrk 501, corresponding to an increase of the γ -ray flux above 1 TeV by a factor of 6.6 ± 2.2 from its steady emission. In particular, the γ -ray flux above 8 TeV is detected with a significance better than 4σ . Based on time-dependent synchrotron self-Compton (SSC) processes, the broadband energy spectrum is interpreted as the emission from an electron energy distribution parameterized with a single power-law function with an exponential cutoff at its high-energy end. The average spectral energy distribution for the steady emission is well described by this simple one-zone SSC model. However, the detection of γ -rays above 8 TeV during the flare challenges this model due to the hardness of the spectra. Correlations between X-rays and γ -rays are also investigated."
2012
B., B., 2, ., P., B., 4, ., X. J., B., C., B., et al. (2012). "LONG-TERM MONITORING OF MRK 501 FOR ITS VERY HIGH ENERGY" "γ EMISSION AND A FLARE IN 2011 OCTOBER". THE ASTROPHYSICAL JOURNAL, 758:2, 1-8 [10.1088/0004-637X/758/1/2].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/122558
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