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

E. Aliu; T. Arlen; T. Aune; M. Beilicke; W. Benbow; A. Bouvier; S. M. Bradbury; J. H. Buckley; V. Bugaev; K. Byrum; A. Cannon; A. Cesarini; L. Ciupik; E. Collins-Hughes; M. P. Connolly; W. Cui; R. Dickherber; C. Duke; M. Errando; A. Falcone; J. P. Finley; G. Finnegan; L. Fortson; A. Furniss; N. Galante; D. Gall; S. Godambe; S. Griffin; J. Grube; R. Guenette; G. Gyuk; D. Hanna; J. Holder; H. Huan; G. Hughes; C. M. Hui; T. B. Humensky; A. Imran; P. Kaaret; N. Karlsson; M. Kertzman; D. Kieda; H. Krawczynski; F. Krennrich; M. J. Lang; S. Lebohec; A. S. Madhavan; G. Maier; P. Majumdar; S. McArthur; A. McCann; P. Moriarty; R. Mukherjee; P. D. Nũez; R. A. Ong; M. Orr; A. N. Otte; N. Park; J. S. Perkins; A. Pichel; M. Pohl; H. Prokoph; J. Quinn; K. Ragan; L. C. Reyes; P. T. Reynolds; E. Roache; H. J. Rose; J. Ruppel; D. B. Saxon; M. Schroedter; G. H. Sembroski; G. D. Entürk; C. Skole; D. Staszak; G. Teić; M. Theiling; S. Thibadeau; K. Tsurusaki; J. Tyler; A. Varlotta; V. V. Vassiliev; S. Vincent; M. Vivier; S. P. Wakely; J. E. Ward; T. C. Weekes; A. Weinstein; T. Weisgarber; D. A. Williams; B. Zitzer

doi:10.1088/0004-637X/746/2/141

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

E. Aliu
, T. Arlen
, T. Aune
, M. Beilicke
, W. Benbow
, A. Bouvier
, S. M. Bradbury
, J. H. Buckley
, V. Bugaev
, K. Byrum
, A. Cannon
, A. Cesarini
, L. Ciupik
, E. Collins-Hughes
, M. P. Connolly
, W. Cui
, R. Dickherber
, C. Duke
, M. Errando
, A. Falcone

J. P. Finley, G. Finnegan, L. Fortson, A. Furniss, N. Galante, D. Gall, S. Godambe, S. Griffin, J. Grube, R. Guenette, G. Gyuk, D. Hanna, J. Holder, H. Huan, G. Hughes, C. M. Hui, T. B. Humensky, A. Imran, P. Kaaret, N. Karlsson, M. Kertzman, D. Kieda, H. Krawczynski, F. Krennrich, M. J. Lang, S. Lebohec, A. S. Madhavan, G. Maier, P. Majumdar, S. McArthur, A. McCann, P. Moriarty, R. Mukherjee, P. D. Nũez, R. A. Ong, M. Orr, A. N. Otte, N. Park, J. S. Perkins, A. Pichel, M. Pohl, H. Prokoph, J. Quinn, K. Ragan, L. C. Reyes, P. T. Reynolds, E. Roache, H. J. Rose, J. Ruppel, D. B. Saxon, M. Schroedter, G. H. Sembroski, G. D. Entürk, C. Skole, D. Staszak, G. Teić, M. Theiling, S. Thibadeau, K. Tsurusaki, J. Tyler, A. Varlotta, V. V. Vassiliev, S. Vincent, M. Vivier, S. P. Wakely, J. E. Ward, T. C. Weekes, A. Weinstein, T. Weisgarber, D. A. Williams, B. Zitzer

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Abstract

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.

Original language	English
Article number	141
Journal	Astrophysical Journal
Volume	746
Issue number	2
DOIs	https://doi.org/10.1088/0004-637X/746/2/141
State	Published - Feb 20 2012

Keywords

gamma rays: galaxies

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10.1088/0004-637X/746/2/141

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Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bouvier, A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Errando, M., ... Zitzer, B. (2012). Veritas observations of day-scale flaring of M 87 in 2010 April. Astrophysical Journal, 746(2), Article 141. https://doi.org/10.1088/0004-637X/746/2/141

@article{e9d9b258c0474b42b02118a74ec7f293,

title = "Veritas observations of day-scale flaring of M 87 in 2010 April",

abstract = "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.",

keywords = "gamma rays: galaxies",

author = "E. Aliu and T. Arlen and T. Aune and M. Beilicke and W. Benbow and A. Bouvier and Bradbury, \{S. M.\} and Buckley, \{J. H.\} and V. Bugaev and K. Byrum and A. Cannon and A. Cesarini and L. Ciupik and E. Collins-Hughes and Connolly, \{M. P.\} and W. Cui and R. Dickherber and C. Duke and M. Errando and A. Falcone and Finley, \{J. P.\} and G. Finnegan and L. Fortson and A. Furniss and N. Galante and D. Gall and S. Godambe and S. Griffin and J. Grube and R. Guenette and G. Gyuk and D. Hanna and J. Holder and H. Huan and G. Hughes and Hui, \{C. M.\} and Humensky, \{T. B.\} and A. Imran and P. Kaaret and N. Karlsson and M. Kertzman and D. Kieda and H. Krawczynski and F. Krennrich and Lang, \{M. J.\} and S. Lebohec and Madhavan, \{A. S.\} and G. Maier and P. Majumdar and S. McArthur and A. McCann and P. Moriarty and R. Mukherjee and Nũez, \{P. D.\} and Ong, \{R. A.\} and M. Orr and Otte, \{A. N.\} and N. Park and Perkins, \{J. S.\} and A. Pichel and M. Pohl and H. Prokoph and J. Quinn and K. Ragan and Reyes, \{L. C.\} and Reynolds, \{P. T.\} and E. Roache and Rose, \{H. J.\} and J. Ruppel and Saxon, \{D. B.\} and M. Schroedter and Sembroski, \{G. H.\} and Ent{\"u}rk, \{G. D.\} and C. Skole and D. Staszak and G. Tei{\'c} and M. Theiling and S. Thibadeau and K. Tsurusaki and J. Tyler and A. Varlotta and Vassiliev, \{V. V.\} and S. Vincent and M. Vivier and Wakely, \{S. P.\} and Ward, \{J. E.\} and Weekes, \{T. C.\} and A. Weinstein and T. Weisgarber and Williams, \{D. A.\} and B. Zitzer",

year = "2012",

month = feb,

day = "20",

doi = "10.1088/0004-637X/746/2/141",

language = "English",

volume = "746",

journal = "Astrophysical Journal",

issn = "0004-637X",

number = "2",

}

Aliu, E, Arlen, T, Aune, T, Beilicke, M, Benbow, W, Bouvier, A, Bradbury, SM, Buckley, JH, Bugaev, V, Byrum, K, Cannon, A, Cesarini, A, Ciupik, L, Collins-Hughes, E, Connolly, MP, Cui, W, Dickherber, R, Duke, C, Errando, M, Falcone, A, Finley, JP, Finnegan, G, Fortson, L, Furniss, A, Galante, N, Gall, D, Godambe, S, Griffin, S, Grube, J, Guenette, R, Gyuk, G, Hanna, D, Holder, J, Huan, H, Hughes, G, Hui, CM, Humensky, TB, Imran, A, Kaaret, P, Karlsson, N, Kertzman, M, Kieda, D, Krawczynski, H, Krennrich, F, Lang, MJ, Lebohec, S, Madhavan, AS, Maier, G, Majumdar, P, McArthur, S, McCann, A, Moriarty, P, Mukherjee, R, Nũez, PD, Ong, RA, Orr, M, Otte, AN, Park, N, Perkins, JS, Pichel, A, Pohl, M, Prokoph, H, Quinn, J, Ragan, K, Reyes, LC, Reynolds, PT, Roache, E, Rose, HJ, Ruppel, J, Saxon, DB, Schroedter, M, Sembroski, GH, Entürk, GD, Skole, C, Staszak, D, Teić, G, Theiling, M, Thibadeau, S, Tsurusaki, K, Tyler, J, Varlotta, A, Vassiliev, VV, Vincent, S, Vivier, M, Wakely, SP, Ward, JE, Weekes, TC, Weinstein, A, Weisgarber, T, Williams, DA & Zitzer, B 2012, 'Veritas observations of day-scale flaring of M 87 in 2010 April', Astrophysical Journal, vol. 746, no. 2, 141. https://doi.org/10.1088/0004-637X/746/2/141

TY - JOUR

T1 - Veritas observations of day-scale flaring of M 87 in 2010 April

AU - Aliu, E.

AU - Arlen, T.

AU - Aune, T.

AU - Beilicke, M.

AU - Benbow, W.

AU - Bouvier, A.

AU - Bradbury, S. M.

AU - Buckley, J. H.

AU - Bugaev, V.

AU - Byrum, K.

AU - Cannon, A.

AU - Cesarini, A.

AU - Ciupik, L.

AU - Collins-Hughes, E.

AU - Connolly, M. P.

AU - Cui, W.

AU - Dickherber, R.

AU - Duke, C.

AU - Errando, M.

AU - Falcone, A.

AU - Finley, J. P.

AU - Finnegan, G.

AU - Fortson, L.

AU - Furniss, A.

AU - Galante, N.

AU - Gall, D.

AU - Godambe, S.

AU - Griffin, S.

AU - Grube, J.

AU - Guenette, R.

AU - Gyuk, G.

AU - Hanna, D.

AU - Holder, J.

AU - Huan, H.

AU - Hughes, G.

AU - Hui, C. M.

AU - Humensky, T. B.

AU - Imran, A.

AU - Kaaret, P.

AU - Karlsson, N.

AU - Kertzman, M.

AU - Kieda, D.

AU - Krawczynski, H.

AU - Krennrich, F.

AU - Lang, M. J.

AU - Lebohec, S.

AU - Madhavan, A. S.

AU - Maier, G.

AU - Majumdar, P.

AU - McArthur, S.

AU - McCann, A.

AU - Moriarty, P.

AU - Mukherjee, R.

AU - Nũez, P. D.

AU - Ong, R. A.

AU - Orr, M.

AU - Otte, A. N.

AU - Park, N.

AU - Perkins, J. S.

AU - Pichel, A.

AU - Pohl, M.

AU - Prokoph, H.

AU - Quinn, J.

AU - Ragan, K.

AU - Reyes, L. C.

AU - Reynolds, P. T.

AU - Roache, E.

AU - Rose, H. J.

AU - Ruppel, J.

AU - Saxon, D. B.

AU - Schroedter, M.

AU - Sembroski, G. H.

AU - Entürk, G. D.

AU - Skole, C.

AU - Staszak, D.

AU - Teić, G.

AU - Theiling, M.

AU - Thibadeau, S.

AU - Tsurusaki, K.

AU - Tyler, J.

AU - Varlotta, A.

AU - Vassiliev, V. V.

AU - Vincent, S.

AU - Vivier, M.

AU - Wakely, S. P.

AU - Ward, J. E.

AU - Weekes, T. C.

AU - Weinstein, A.

AU - Weisgarber, T.

AU - Williams, D. A.

AU - Zitzer, B.

PY - 2012/2/20

Y1 - 2012/2/20

N2 - 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.

AB - 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.

KW - gamma rays: galaxies

UR - https://www.scopus.com/pages/publications/84863156661

U2 - 10.1088/0004-637X/746/2/141

DO - 10.1088/0004-637X/746/2/141

M3 - Article

AN - SCOPUS:84863156661

SN - 0004-637X

VL - 746

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 141

ER -

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

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