The very high energy gamma ray spectra of IES 1959+650 and Mrk 421 as measured with the Whipple 10 m telescope

M. K. Daniel, H. M. Badran, I. H. Bond, P. J. Boyle, S. M. Bradbury, J. H. Buckley, K. Byrum, D. A. Carter-Lewis, O. Celik, P. Cogan, W. Cui, I. De La Calle Perez, C. Duke, A. Falcone, D. J. Fegan, S. J. Fegan, J. P. Finley, L. F. Fortson, S. Gammell, K. GibbsG. H. Gillanders, J. Grube, K. J. Guiterrez, J. Hall, D. Hanna, J. Holder, D. Horan, S. Hughes, T. B. Humensky, I. Jung, G. E. Kenny, M. Kertzman, D. Kieda, J. Kildea, J. Knapp, K. Kosack, H. Krawczynski, F. Krennrich, M. J. Lang, S. Le Bohec, E. Linton, J. Lloyd-Evans, D. Mendoza, A. Merriman, A. Milovanovic, P. Moriarty, T. Nagai, R. A. Ong, R. Pallassini, J. Perkins, D. Petry, M. Pohl, B. Power-Mooney, J. Quinn, M. Quinn, K. Ragan, P. Rebillot, P. T. Reynolds, H. J. Rose, M. Schroedter, G. H. Sembroski, S. P. Swordy, A. Syson, L. Valcarcel, V. V. Vassiliev, R. Wagner, S. P. Wakely, G. Walker, T. C. Weekes, R. J. White, J. Zweerink

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In observations made with the Whipple 10 m telescope, 1ES 1959+650 (z = 0.048) was caught in a high flaring state in May 2002, concurrent with a high X-ray state, and in June 2002, for which there was no corresponding X-ray flare. The spectra for both of those occasions are well fitted by a power law of differential spectral index ∼ -2.8. The relative stability of the spectral index for those flares argues strongly in favour of a two-component model as to the emission zones for the two radiation regimes. Markarian 421 (z = 0.031) was observed to be in a high flaring state, at levels of ≥ 3 Crab, during March and April 2004. The average spectrum over this time period shows evidence for a cut-off in the spectrum at ∼ 5 TeV, similar to a cut-off seen during an equivalently strong episode of flaring activity in 2001. The continued appearance of this feature indicates a long term stability, either in the physical conditions at the source, or in the intervening medium (such as attenuation on the extra-galactic infra-red background radiation).

Original languageEnglish (US)
Title of host publicationHigh Energy Gamma-Ray Astronomy - 2nd International Symposium on High Energy Gamma-Ray Astronomy
Pages462-467
Number of pages6
DOIs
StatePublished - Dec 1 2005
EventInternational Symposium on High Energy Gamma-Ray Astronomy - Heidelberg, Germany
Duration: Jul 26 2004Jul 30 2004

Publication series

NameAIP Conference Proceedings
Volume745
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

OtherInternational Symposium on High Energy Gamma-Ray Astronomy
CountryGermany
CityHeidelberg
Period7/26/047/30/04

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gamma ray spectra
energy spectra
telescopes
flares
cut-off
crabs
background radiation
x rays
attenuation
radiation

Cite this

Daniel, M. K., Badran, H. M., Bond, I. H., Boyle, P. J., Bradbury, S. M., Buckley, J. H., ... Zweerink, J. (2005). The very high energy gamma ray spectra of IES 1959+650 and Mrk 421 as measured with the Whipple 10 m telescope. In High Energy Gamma-Ray Astronomy - 2nd International Symposium on High Energy Gamma-Ray Astronomy (pp. 462-467). (AIP Conference Proceedings; Vol. 745). https://doi.org/10.1063/1.1878446

The very high energy gamma ray spectra of IES 1959+650 and Mrk 421 as measured with the Whipple 10 m telescope. / Daniel, M. K.; Badran, H. M.; Bond, I. H.; Boyle, P. J.; Bradbury, S. M.; Buckley, J. H.; Byrum, K.; Carter-Lewis, D. A.; Celik, O.; Cogan, P.; Cui, W.; De La Calle Perez, I.; Duke, C.; Falcone, A.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fortson, L. F.; Gammell, S.; Gibbs, K.; Gillanders, G. H.; Grube, J.; Guiterrez, K. J.; Hall, J.; Hanna, D.; Holder, J.; Horan, D.; Hughes, S.; Humensky, T. B.; Jung, I.; Kenny, G. E.; Kertzman, M.; Kieda, D.; Kildea, J.; Knapp, J.; Kosack, K.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; Le Bohec, S.; Linton, E.; Lloyd-Evans, J.; Mendoza, D.; Merriman, A.; Milovanovic, A.; Moriarty, P.; Nagai, T.; Ong, R. A.; Pallassini, R.; Perkins, J.; Petry, D.; Pohl, M.; Power-Mooney, B.; Quinn, J.; Quinn, M.; Ragan, K.; Rebillot, P.; Reynolds, P. T.; Rose, H. J.; Schroedter, M.; Sembroski, G. H.; Swordy, S. P.; Syson, A.; Valcarcel, L.; Vassiliev, V. V.; Wagner, R.; Wakely, S. P.; Walker, G.; Weekes, T. C.; White, R. J.; Zweerink, J.

High Energy Gamma-Ray Astronomy - 2nd International Symposium on High Energy Gamma-Ray Astronomy. 2005. p. 462-467 (AIP Conference Proceedings; Vol. 745).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Daniel, MK, Badran, HM, Bond, IH, Boyle, PJ, Bradbury, SM, Buckley, JH, Byrum, K, Carter-Lewis, DA, Celik, O, Cogan, P, Cui, W, De La Calle Perez, I, Duke, C, Falcone, A, Fegan, DJ, Fegan, SJ, Finley, JP, Fortson, LF, Gammell, S, Gibbs, K, Gillanders, GH, Grube, J, Guiterrez, KJ, Hall, J, Hanna, D, Holder, J, Horan, D, Hughes, S, Humensky, TB, Jung, I, Kenny, GE, Kertzman, M, Kieda, D, Kildea, J, Knapp, J, Kosack, K, Krawczynski, H, Krennrich, F, Lang, MJ, Le Bohec, S, Linton, E, Lloyd-Evans, J, Mendoza, D, Merriman, A, Milovanovic, A, Moriarty, P, Nagai, T, Ong, RA, Pallassini, R, Perkins, J, Petry, D, Pohl, M, Power-Mooney, B, Quinn, J, Quinn, M, Ragan, K, Rebillot, P, Reynolds, PT, Rose, HJ, Schroedter, M, Sembroski, GH, Swordy, SP, Syson, A, Valcarcel, L, Vassiliev, VV, Wagner, R, Wakely, SP, Walker, G, Weekes, TC, White, RJ & Zweerink, J 2005, The very high energy gamma ray spectra of IES 1959+650 and Mrk 421 as measured with the Whipple 10 m telescope. in High Energy Gamma-Ray Astronomy - 2nd International Symposium on High Energy Gamma-Ray Astronomy. AIP Conference Proceedings, vol. 745, pp. 462-467, International Symposium on High Energy Gamma-Ray Astronomy, Heidelberg, Germany, 7/26/04. https://doi.org/10.1063/1.1878446
Daniel MK, Badran HM, Bond IH, Boyle PJ, Bradbury SM, Buckley JH et al. The very high energy gamma ray spectra of IES 1959+650 and Mrk 421 as measured with the Whipple 10 m telescope. In High Energy Gamma-Ray Astronomy - 2nd International Symposium on High Energy Gamma-Ray Astronomy. 2005. p. 462-467. (AIP Conference Proceedings). https://doi.org/10.1063/1.1878446
Daniel, M. K. ; Badran, H. M. ; Bond, I. H. ; Boyle, P. J. ; Bradbury, S. M. ; Buckley, J. H. ; Byrum, K. ; Carter-Lewis, D. A. ; Celik, O. ; Cogan, P. ; Cui, W. ; De La Calle Perez, I. ; Duke, C. ; Falcone, A. ; Fegan, D. J. ; Fegan, S. J. ; Finley, J. P. ; Fortson, L. F. ; Gammell, S. ; Gibbs, K. ; Gillanders, G. H. ; Grube, J. ; Guiterrez, K. J. ; Hall, J. ; Hanna, D. ; Holder, J. ; Horan, D. ; Hughes, S. ; Humensky, T. B. ; Jung, I. ; Kenny, G. E. ; Kertzman, M. ; Kieda, D. ; Kildea, J. ; Knapp, J. ; Kosack, K. ; Krawczynski, H. ; Krennrich, F. ; Lang, M. J. ; Le Bohec, S. ; Linton, E. ; Lloyd-Evans, J. ; Mendoza, D. ; Merriman, A. ; Milovanovic, A. ; Moriarty, P. ; Nagai, T. ; Ong, R. A. ; Pallassini, R. ; Perkins, J. ; Petry, D. ; Pohl, M. ; Power-Mooney, B. ; Quinn, J. ; Quinn, M. ; Ragan, K. ; Rebillot, P. ; Reynolds, P. T. ; Rose, H. J. ; Schroedter, M. ; Sembroski, G. H. ; Swordy, S. P. ; Syson, A. ; Valcarcel, L. ; Vassiliev, V. V. ; Wagner, R. ; Wakely, S. P. ; Walker, G. ; Weekes, T. C. ; White, R. J. ; Zweerink, J. / The very high energy gamma ray spectra of IES 1959+650 and Mrk 421 as measured with the Whipple 10 m telescope. High Energy Gamma-Ray Astronomy - 2nd International Symposium on High Energy Gamma-Ray Astronomy. 2005. pp. 462-467 (AIP Conference Proceedings).
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title = "The very high energy gamma ray spectra of IES 1959+650 and Mrk 421 as measured with the Whipple 10 m telescope",
abstract = "In observations made with the Whipple 10 m telescope, 1ES 1959+650 (z = 0.048) was caught in a high flaring state in May 2002, concurrent with a high X-ray state, and in June 2002, for which there was no corresponding X-ray flare. The spectra for both of those occasions are well fitted by a power law of differential spectral index ∼ -2.8. The relative stability of the spectral index for those flares argues strongly in favour of a two-component model as to the emission zones for the two radiation regimes. Markarian 421 (z = 0.031) was observed to be in a high flaring state, at levels of ≥ 3 Crab, during March and April 2004. The average spectrum over this time period shows evidence for a cut-off in the spectrum at ∼ 5 TeV, similar to a cut-off seen during an equivalently strong episode of flaring activity in 2001. The continued appearance of this feature indicates a long term stability, either in the physical conditions at the source, or in the intervening medium (such as attenuation on the extra-galactic infra-red background radiation).",
author = "Daniel, {M. K.} and Badran, {H. M.} and Bond, {I. H.} and Boyle, {P. J.} and Bradbury, {S. M.} and Buckley, {J. H.} and K. Byrum and Carter-Lewis, {D. A.} and O. Celik and P. Cogan and W. Cui and {De La Calle Perez}, I. and C. Duke and A. Falcone and Fegan, {D. J.} and Fegan, {S. J.} and Finley, {J. P.} and Fortson, {L. F.} and S. Gammell and K. Gibbs and Gillanders, {G. H.} and J. Grube and Guiterrez, {K. J.} and J. Hall and D. Hanna and J. Holder and D. Horan and S. Hughes and Humensky, {T. B.} and I. Jung and Kenny, {G. E.} and M. Kertzman and D. Kieda and J. Kildea and J. Knapp and K. Kosack and H. Krawczynski and F. Krennrich and Lang, {M. J.} and {Le Bohec}, S. and E. Linton and J. Lloyd-Evans and D. Mendoza and A. Merriman and A. Milovanovic and P. Moriarty and T. Nagai and Ong, {R. A.} and R. Pallassini and J. Perkins and D. Petry and M. Pohl and B. Power-Mooney and J. Quinn and M. Quinn and K. Ragan and P. Rebillot and Reynolds, {P. T.} and Rose, {H. J.} and M. Schroedter and Sembroski, {G. H.} and Swordy, {S. P.} and A. Syson and L. Valcarcel and Vassiliev, {V. V.} and R. Wagner and Wakely, {S. P.} and G. Walker and Weekes, {T. C.} and White, {R. J.} and J. Zweerink",
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T1 - The very high energy gamma ray spectra of IES 1959+650 and Mrk 421 as measured with the Whipple 10 m telescope

AU - Daniel, M. K.

AU - Badran, H. M.

AU - Bond, I. H.

AU - Boyle, P. J.

AU - Bradbury, S. M.

AU - Buckley, J. H.

AU - Byrum, K.

AU - Carter-Lewis, D. A.

AU - Celik, O.

AU - Cogan, P.

AU - Cui, W.

AU - De La Calle Perez, I.

AU - Duke, C.

AU - Falcone, A.

AU - Fegan, D. J.

AU - Fegan, S. J.

AU - Finley, J. P.

AU - Fortson, L. F.

AU - Gammell, S.

AU - Gibbs, K.

AU - Gillanders, G. H.

AU - Grube, J.

AU - Guiterrez, K. J.

AU - Hall, J.

AU - Hanna, D.

AU - Holder, J.

AU - Horan, D.

AU - Hughes, S.

AU - Humensky, T. B.

AU - Jung, I.

AU - Kenny, G. E.

AU - Kertzman, M.

AU - Kieda, D.

AU - Kildea, J.

AU - Knapp, J.

AU - Kosack, K.

AU - Krawczynski, H.

AU - Krennrich, F.

AU - Lang, M. J.

AU - Le Bohec, S.

AU - Linton, E.

AU - Lloyd-Evans, J.

AU - Mendoza, D.

AU - Merriman, A.

AU - Milovanovic, A.

AU - Moriarty, P.

AU - Nagai, T.

AU - Ong, R. A.

AU - Pallassini, R.

AU - Perkins, J.

AU - Petry, D.

AU - Pohl, M.

AU - Power-Mooney, B.

AU - Quinn, J.

AU - Quinn, M.

AU - Ragan, K.

AU - Rebillot, P.

AU - Reynolds, P. T.

AU - Rose, H. J.

AU - Schroedter, M.

AU - Sembroski, G. H.

AU - Swordy, S. P.

AU - Syson, A.

AU - Valcarcel, L.

AU - Vassiliev, V. V.

AU - Wagner, R.

AU - Wakely, S. P.

AU - Walker, G.

AU - Weekes, T. C.

AU - White, R. J.

AU - Zweerink, J.

PY - 2005/12/1

Y1 - 2005/12/1

N2 - In observations made with the Whipple 10 m telescope, 1ES 1959+650 (z = 0.048) was caught in a high flaring state in May 2002, concurrent with a high X-ray state, and in June 2002, for which there was no corresponding X-ray flare. The spectra for both of those occasions are well fitted by a power law of differential spectral index ∼ -2.8. The relative stability of the spectral index for those flares argues strongly in favour of a two-component model as to the emission zones for the two radiation regimes. Markarian 421 (z = 0.031) was observed to be in a high flaring state, at levels of ≥ 3 Crab, during March and April 2004. The average spectrum over this time period shows evidence for a cut-off in the spectrum at ∼ 5 TeV, similar to a cut-off seen during an equivalently strong episode of flaring activity in 2001. The continued appearance of this feature indicates a long term stability, either in the physical conditions at the source, or in the intervening medium (such as attenuation on the extra-galactic infra-red background radiation).

AB - In observations made with the Whipple 10 m telescope, 1ES 1959+650 (z = 0.048) was caught in a high flaring state in May 2002, concurrent with a high X-ray state, and in June 2002, for which there was no corresponding X-ray flare. The spectra for both of those occasions are well fitted by a power law of differential spectral index ∼ -2.8. The relative stability of the spectral index for those flares argues strongly in favour of a two-component model as to the emission zones for the two radiation regimes. Markarian 421 (z = 0.031) was observed to be in a high flaring state, at levels of ≥ 3 Crab, during March and April 2004. The average spectrum over this time period shows evidence for a cut-off in the spectrum at ∼ 5 TeV, similar to a cut-off seen during an equivalently strong episode of flaring activity in 2001. The continued appearance of this feature indicates a long term stability, either in the physical conditions at the source, or in the intervening medium (such as attenuation on the extra-galactic infra-red background radiation).

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