Investigating broadband variability of the TeV blazar 1ES 1959+650

The VERITAS Collaboration

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We summarize broadband observations of the TeV-emitting blazar 1ES 1959+650, including optical R-band observations by the robotic telescopes Super-LOTIS and iTelescope, UV observations by Swift Ultraviolet and Optical Telescope, X-ray observations by the Swift X-ray Telescope, high-energy gamma-ray observations with the Fermi Large Area Telescope, and very-high-energy (VHE) gamma-ray observations by VERITAS above 315 GeV, all taken between 2012 April 17 and 2012 June 1 (MJD 56034 and 56079). The contemporaneous variability of the broadband spectral energy distribution is explored in the context of a simple synchrotron self Compton (SSC) model. In the SSC emission scenario, we find that the parameters required to represent the high state are significantly different than those in the low state. Motivated by possible evidence of gas in the vicinity of the blazar, we also investigate a reflected emission model to describe the observed variability pattern. This model assumes that the non-thermal emission from the jet is reflected by a nearby cloud of gas, allowing the reflected emission to re-enter the blob and produce an elevated gamma-ray state with no simultaneous elevated synchrotron flux. The model applied here, although not required to explain the observed variability pattern, represents one possible scenario which can describe the observations. As applied to an elevated VHE state of 66% of the Crab Nebula flux, observed on a single night during the observation period, the reflected emission scenario does not support a purely leptonic non-thermal emission mechanism. The reflected emission model does, however, predict a reflected photon field with sufficient energy to enable elevated gamma-ray emission via pion production with protons of energies between 10 and 100 TeV.

Original languageEnglish (US)
Article number89
JournalAstrophysical Journal
Volume797
Issue number2
DOIs
StatePublished - Dec 20 2014

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broadband
gamma rays
telescopes
energy
nonthermal radiation
synchrotrons
ultraviolet telescopes
Crab nebula
robotics
spectral energy distribution
gases
gas
night
crab
pions
x rays
protons
photons

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

The VERITAS Collaboration. / Investigating broadband variability of the TeV blazar 1ES 1959+650. In: Astrophysical Journal. 2014 ; Vol. 797, No. 2.
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abstract = "We summarize broadband observations of the TeV-emitting blazar 1ES 1959+650, including optical R-band observations by the robotic telescopes Super-LOTIS and iTelescope, UV observations by Swift Ultraviolet and Optical Telescope, X-ray observations by the Swift X-ray Telescope, high-energy gamma-ray observations with the Fermi Large Area Telescope, and very-high-energy (VHE) gamma-ray observations by VERITAS above 315 GeV, all taken between 2012 April 17 and 2012 June 1 (MJD 56034 and 56079). The contemporaneous variability of the broadband spectral energy distribution is explored in the context of a simple synchrotron self Compton (SSC) model. In the SSC emission scenario, we find that the parameters required to represent the high state are significantly different than those in the low state. Motivated by possible evidence of gas in the vicinity of the blazar, we also investigate a reflected emission model to describe the observed variability pattern. This model assumes that the non-thermal emission from the jet is reflected by a nearby cloud of gas, allowing the reflected emission to re-enter the blob and produce an elevated gamma-ray state with no simultaneous elevated synchrotron flux. The model applied here, although not required to explain the observed variability pattern, represents one possible scenario which can describe the observations. As applied to an elevated VHE state of 66{\%} of the Crab Nebula flux, observed on a single night during the observation period, the reflected emission scenario does not support a purely leptonic non-thermal emission mechanism. The reflected emission model does, however, predict a reflected photon field with sufficient energy to enable elevated gamma-ray emission via pion production with protons of energies between 10 and 100 TeV.",
author = "{The VERITAS Collaboration} and E. Aliu and S. Archambault and T. Arlen and T. Aune and A. Barnacka and M. Beilicke and W. Benbow and K. Berger and R. Bird and A. Bouvier and Buckley, {J. H.} and V. Bugaev and M. Cerruti and X. Chen and L. Ciupik and E. Collins-Hughes and Connolly, {M. P.} and W. Cui and J. Dumm and Eisch, {J. D.} and A. Falcone and S. Federici and Q. Feng and Finley, {J. P.} and H. Fleischhack and P. Fortin and L. Fortson and A. Furniss and N. Galante and Gillanders, {G. H.} and S. Griffin and Griffiths, {S. T.} and J. Grube and G. Gyuk and N. H{\aa}kansson and D. Hanna and J. Holder and G. Hughes and Z. Hughes and Humensky, {T. B.} and Johnson, {C. A.} and P. Kaaret and P. Kar and M. Kertzman and Y. Khassen and D. Kieda and H. Krawczynski and F. Krennrich and Lang, {M. J.} and Madhavan, {A. S.}",
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Investigating broadband variability of the TeV blazar 1ES 1959+650. / The VERITAS Collaboration.

In: Astrophysical Journal, Vol. 797, No. 2, 89, 20.12.2014.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Investigating broadband variability of the TeV blazar 1ES 1959+650

AU - The VERITAS Collaboration

AU - Aliu, E.

AU - Archambault, S.

AU - Arlen, T.

AU - Aune, T.

AU - Barnacka, A.

AU - Beilicke, M.

AU - Benbow, W.

AU - Berger, K.

AU - Bird, R.

AU - Bouvier, A.

AU - Buckley, J. H.

AU - Bugaev, V.

AU - Cerruti, M.

AU - Chen, X.

AU - Ciupik, L.

AU - Collins-Hughes, E.

AU - Connolly, M. P.

AU - Cui, W.

AU - Dumm, J.

AU - Eisch, J. D.

AU - Falcone, A.

AU - Federici, S.

AU - Feng, Q.

AU - Finley, J. P.

AU - Fleischhack, H.

AU - Fortin, P.

AU - Fortson, L.

AU - Furniss, A.

AU - Galante, N.

AU - Gillanders, G. H.

AU - Griffin, S.

AU - Griffiths, S. T.

AU - Grube, J.

AU - Gyuk, G.

AU - Håkansson, N.

AU - Hanna, D.

AU - Holder, J.

AU - Hughes, G.

AU - Hughes, Z.

AU - Humensky, T. B.

AU - Johnson, C. A.

AU - Kaaret, P.

AU - Kar, P.

AU - Kertzman, M.

AU - Khassen, Y.

AU - Kieda, D.

AU - Krawczynski, H.

AU - Krennrich, F.

AU - Lang, M. J.

AU - Madhavan, A. S.

PY - 2014/12/20

Y1 - 2014/12/20

N2 - We summarize broadband observations of the TeV-emitting blazar 1ES 1959+650, including optical R-band observations by the robotic telescopes Super-LOTIS and iTelescope, UV observations by Swift Ultraviolet and Optical Telescope, X-ray observations by the Swift X-ray Telescope, high-energy gamma-ray observations with the Fermi Large Area Telescope, and very-high-energy (VHE) gamma-ray observations by VERITAS above 315 GeV, all taken between 2012 April 17 and 2012 June 1 (MJD 56034 and 56079). The contemporaneous variability of the broadband spectral energy distribution is explored in the context of a simple synchrotron self Compton (SSC) model. In the SSC emission scenario, we find that the parameters required to represent the high state are significantly different than those in the low state. Motivated by possible evidence of gas in the vicinity of the blazar, we also investigate a reflected emission model to describe the observed variability pattern. This model assumes that the non-thermal emission from the jet is reflected by a nearby cloud of gas, allowing the reflected emission to re-enter the blob and produce an elevated gamma-ray state with no simultaneous elevated synchrotron flux. The model applied here, although not required to explain the observed variability pattern, represents one possible scenario which can describe the observations. As applied to an elevated VHE state of 66% of the Crab Nebula flux, observed on a single night during the observation period, the reflected emission scenario does not support a purely leptonic non-thermal emission mechanism. The reflected emission model does, however, predict a reflected photon field with sufficient energy to enable elevated gamma-ray emission via pion production with protons of energies between 10 and 100 TeV.

AB - We summarize broadband observations of the TeV-emitting blazar 1ES 1959+650, including optical R-band observations by the robotic telescopes Super-LOTIS and iTelescope, UV observations by Swift Ultraviolet and Optical Telescope, X-ray observations by the Swift X-ray Telescope, high-energy gamma-ray observations with the Fermi Large Area Telescope, and very-high-energy (VHE) gamma-ray observations by VERITAS above 315 GeV, all taken between 2012 April 17 and 2012 June 1 (MJD 56034 and 56079). The contemporaneous variability of the broadband spectral energy distribution is explored in the context of a simple synchrotron self Compton (SSC) model. In the SSC emission scenario, we find that the parameters required to represent the high state are significantly different than those in the low state. Motivated by possible evidence of gas in the vicinity of the blazar, we also investigate a reflected emission model to describe the observed variability pattern. This model assumes that the non-thermal emission from the jet is reflected by a nearby cloud of gas, allowing the reflected emission to re-enter the blob and produce an elevated gamma-ray state with no simultaneous elevated synchrotron flux. The model applied here, although not required to explain the observed variability pattern, represents one possible scenario which can describe the observations. As applied to an elevated VHE state of 66% of the Crab Nebula flux, observed on a single night during the observation period, the reflected emission scenario does not support a purely leptonic non-thermal emission mechanism. The reflected emission model does, however, predict a reflected photon field with sufficient energy to enable elevated gamma-ray emission via pion production with protons of energies between 10 and 100 TeV.

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U2 - 10.1088/0004-637X/797/2/89

DO - 10.1088/0004-637X/797/2/89

M3 - Article

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VL - 797

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

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