Veritas observations of day-scale flaring of M 87 in 2010 April

VERITAS has been monitoring the very-high-energy (VHE; >100GeV) 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 350GeV. In 2010 April, VERITAS d...

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Publicado:	2012
Materias:	gamma rays: galaxies
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v746_n2_p_Aliu http://hdl.handle.net/20.500.12110/paper_0004637X_v746_n2_p_Aliu
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_0004637X_v746_n2_p_Aliu
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spelling	paper:paper_0004637X_v746_n2_p_Aliu2023-06-08T14:29:04Z Veritas observations of day-scale flaring of M 87 in 2010 April gamma rays: galaxies VERITAS has been monitoring the very-high-energy (VHE; >100GeV) 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 350GeV. 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 > 350GeV. 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 -0.15days. The shortest detected exponential rise time is three times as long, at 2.87 +1.65 -0.99days. 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. © 2012. The American Astronomical Society. All rights reserved. 2012 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v746_n2_p_Aliu http://hdl.handle.net/20.500.12110/paper_0004637X_v746_n2_p_Aliu
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	gamma rays: galaxies
spellingShingle	gamma rays: galaxies Veritas observations of day-scale flaring of M 87 in 2010 April
topic_facet	gamma rays: galaxies
description	VERITAS has been monitoring the very-high-energy (VHE; >100GeV) 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 350GeV. 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 > 350GeV. 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 -0.15days. The shortest detected exponential rise time is three times as long, at 2.87 +1.65 -0.99days. 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. © 2012. The American Astronomical Society. All rights reserved.
title	Veritas observations of day-scale flaring of M 87 in 2010 April
title_short	Veritas observations of day-scale flaring of M 87 in 2010 April
title_full	Veritas observations of day-scale flaring of M 87 in 2010 April
title_fullStr	Veritas observations of day-scale flaring of M 87 in 2010 April
title_full_unstemmed	Veritas observations of day-scale flaring of M 87 in 2010 April
title_sort	veritas observations of day-scale flaring of m 87 in 2010 april
publishDate	2012
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0004637X_v746_n2_p_Aliu http://hdl.handle.net/20.500.12110/paper_0004637X_v746_n2_p_Aliu
_version_	1768543064872189952

Veritas observations of day-scale flaring of M 87 in 2010 April

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