Very-high-energy γ -ray observations of the Blazar 1ES 2344+514 with VERITAS

C. Allen; S. Archambault; A. Archer; W. Benbow; R. Bird; E. Bourbeau; R. Brose; M. Buchovecky; J. H. Buckley; V. Bugaev; J. V. Cardenzana; M. Cerruti; X. Chen; J. L. Christiansen; M. P. Connolly; W. Cui; M. K. Daniel; J. D. Eisch; A. Falcone; Q. Feng; M. Fernandez-Alonso; J. P. Finley; H. Fleischhack; A. Flinders; L. Fortson; A. Furniss; G. H. Gillanders; S. Griffin; J. Grube; M. Hütten; N. Håkansson; D. Hanna; O. Hervet; J. Holder; G. Hughes; T. B. Humensky; C. A. Johnson; P. Kaaret; P. Kar; N. Kelley-Hoskins; M. Kertzman; D. Kieda; M. Krause; F. Krennrich; S. Kumar; M. J. Lang; G. Maier; S. McArthur; A. McCann; K. Meagher; P. Moriarty; R. Mukherjee; T. Nguyen; D. Nieto; S. O'Brien; A. O'Faoláin de Bhróithe; R. A. Ong; A. N. Otte; N. Park; A. Petrashyk; A. Pichel; M. Pohl; A. Popkow; E. Pueschel; J. Quinn; K. Ragan; P. T. Reynolds; G. T. Richards; E. Roache; A. C. Rovero; C. Rulten; I. Sadeh; M. Santander; G. H. Sembroski; K. Shahinyan; I. Telezhinsky; J. V. Tucci; J. Tyler; S. P. Wakely; A. Weinstein; A. Wilhelm; D. A. Williams

doi:10.1093/mnras/stx1756

Very-high-energy γ -ray observations of the Blazar 1ES 2344+514 with VERITAS

C. Allen, S. Archambault, A. Archer, W. Benbow, R. Bird, E. Bourbeau, R. Brose, M. Buchovecky, J. H. Buckley, V. Bugaev, J. V. Cardenzana, M. Cerruti, X. Chen, J. L. Christiansen, M. P. Connolly, W. Cui, M. K. Daniel, J. D. Eisch, A. Falcone, Q. FengM. Fernandez-Alonso, J. P. Finley, H. Fleischhack, A. Flinders, L. Fortson, A. Furniss, G. H. Gillanders, S. Griffin, J. Grube, M. Hütten, N. Håkansson, D. Hanna, O. Hervet, J. Holder, G. Hughes, T. B. Humensky, C. A. Johnson, P. Kaaret, P. Kar, N. Kelley-Hoskins, M. Kertzman, D. Kieda, M. Krause, F. Krennrich, S. Kumar, M. J. Lang, G. Maier, S. McArthur, A. McCann, K. Meagher, P. Moriarty, R. Mukherjee, T. Nguyen, D. Nieto, S. O'Brien, A. O'Faoláin de Bhróithe, R. A. Ong, A. N. Otte, N. Park, A. Petrashyk, A. Pichel, M. Pohl, A. Popkow, E. Pueschel, J. Quinn, K. Ragan, P. T. Reynolds, G. T. Richards, E. Roache, A. C. Rovero, C. Rulten, I. Sadeh, M. Santander, G. H. Sembroski, K. Shahinyan, I. Telezhinsky, J. V. Tucci, J. Tyler, S. P. Wakely, A. Weinstein, A. Wilhelm, D. A. Williams

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Abstract

We present very-high-energy γ -ray observations of the BL Lac object 1ES 2344+514 taken by the Very Energetic Radiation Imaging Telescope Array System between 2007 and 2015. 1ES 2344+514 is detected with a statistical significance above the background of 20.8σ in 47.2 h (livetime) of observations, making this the most comprehensive very-high-energy study of 1ES 2344+514 to date. Using these observations, the temporal properties of 1ES 2344+514 are studied on short and long times-scales. We fit a constant-flux model to nightly and seasonally binned light curves and apply a fractional variability test to determine the stability of the source on different time-scales. We reject the constant-flux model for the 2007-2008 and 2014-2015 nightly binned light curves and for the long-term seasonally binned light curve at the > 3σ level. The spectra of the time-averaged emission before and after correction for attenuation by the extragalactic background light are obtained. The observed time-averaged spectrum above 200 GeV is satisfactorily fitted (χ²/NDF = 7.89/6) by a power-law function with an index Γ = 2.46 ± 0.06_stat ± 0.20_sys and extends to at least 8 TeV. The extragalactic-backgroundlight- deabsorbed spectrum is adequately fit (χ²/NDF = 6.73/6) by a power-law function with an index Γ = 2.15 ± 0.06_stat ± 0.20_sys while an F-test indicates that the power law with an exponential cut-offfunction provides a marginally better fit (χ²/NDF = 2.56/5) at the 2.1σ level. The source location is found to be consistent with the published radio location and its spatial extent is consistent with a point source.

Original language	English (US)
Pages (from-to)	2117-2123
Number of pages	7
Journal	Monthly Notices of the Royal Astronomical Society
Volume	471
Issue number	2
DOIs	https://doi.org/10.1093/mnras/stx1756
State	Published - Oct 2017

Bibliographical note

Funding Information:
This research is supported by grants from the U.S. Department of Energy Office of Science, the U.S. National Science Foundation and the Smithsonian Institution, and by NSERC in Canada. We acknowledge the excellent work of the technical support staffat the Fred Lawrence Whipple Observatory and at the collaborating institutions in the construction and operation of the instrument. S. O'Brien is funded by a UCD Research Scholarship. The VERITAS Collaboration is grateful to TrevorWeekes for his seminal contributions and leadership in the field of VHE gamma-ray astrophysics, which made this study possible.

Publisher Copyright:
© 2017 The Authors.

Keywords

Astroparticle physics
BL Lacertae objects: individual: 1ES 2344+514 = VER J2347+517
Gamma-rays: galaxies

Publisher link

10.1093/mnras/stx1756

http://bib-pubdb1.desy.de/record/393401/files/stx1756.pdf

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Allen, C., Archambault, S., Archer, A., Benbow, W., Bird, R., Bourbeau, E., Brose, R., Buchovecky, M., Buckley, J. H., Bugaev, V., Cardenzana, J. V., Cerruti, M., Chen, X., Christiansen, J. L., Connolly, M. P., Cui, W., Daniel, M. K., Eisch, J. D., Falcone, A., ... Williams, D. A. (2017). Very-high-energy γ -ray observations of the Blazar 1ES 2344+514 with VERITAS. Monthly Notices of the Royal Astronomical Society, 471(2), 2117-2123. https://doi.org/10.1093/mnras/stx1756

Allen, C, Archambault, S, Archer, A, Benbow, W, Bird, R, Bourbeau, E, Brose, R, Buchovecky, M, Buckley, JH, Bugaev, V, Cardenzana, JV, Cerruti, M, Chen, X, Christiansen, JL, Connolly, MP, Cui, W, Daniel, MK, Eisch, JD, Falcone, A, Feng, Q, Fernandez-Alonso, M, Finley, JP, Fleischhack, H, Flinders, A, Fortson, L, Furniss, A, Gillanders, GH, Griffin, S, Grube, J, Hütten, M, Håkansson, N, Hanna, D, Hervet, O, Holder, J, Hughes, G, Humensky, TB, Johnson, CA, Kaaret, P, Kar, P, Kelley-Hoskins, N, Kertzman, M, Kieda, D, Krause, M, Krennrich, F, Kumar, S, Lang, MJ, Maier, G, McArthur, S, McCann, A, Meagher, K, Moriarty, P, Mukherjee, R, Nguyen, T, Nieto, D, O'Brien, S, O'Faoláin de Bhróithe, A, Ong, RA, Otte, AN, Park, N, Petrashyk, A, Pichel, A, Pohl, M, Popkow, A, Pueschel, E, Quinn, J, Ragan, K, Reynolds, PT, Richards, GT, Roache, E, Rovero, AC, Rulten, C, Sadeh, I, Santander, M, Sembroski, GH, Shahinyan, K, Telezhinsky, I, Tucci, JV, Tyler, J, Wakely, SP, Weinstein, A, Wilhelm, A & Williams, DA 2017, 'Very-high-energy γ -ray observations of the Blazar 1ES 2344+514 with VERITAS', Monthly Notices of the Royal Astronomical Society, vol. 471, no. 2, pp. 2117-2123. https://doi.org/10.1093/mnras/stx1756

@article{e4680782d40449e0a321f97b5cdff252,

title = "Very-high-energy γ -ray observations of the Blazar 1ES 2344+514 with VERITAS",

abstract = "We present very-high-energy γ -ray observations of the BL Lac object 1ES 2344+514 taken by the Very Energetic Radiation Imaging Telescope Array System between 2007 and 2015. 1ES 2344+514 is detected with a statistical significance above the background of 20.8σ in 47.2 h (livetime) of observations, making this the most comprehensive very-high-energy study of 1ES 2344+514 to date. Using these observations, the temporal properties of 1ES 2344+514 are studied on short and long times-scales. We fit a constant-flux model to nightly and seasonally binned light curves and apply a fractional variability test to determine the stability of the source on different time-scales. We reject the constant-flux model for the 2007-2008 and 2014-2015 nightly binned light curves and for the long-term seasonally binned light curve at the > 3σ level. The spectra of the time-averaged emission before and after correction for attenuation by the extragalactic background light are obtained. The observed time-averaged spectrum above 200 GeV is satisfactorily fitted (χ2/NDF = 7.89/6) by a power-law function with an index Γ = 2.46 ± 0.06stat ± 0.20sys and extends to at least 8 TeV. The extragalactic-backgroundlight- deabsorbed spectrum is adequately fit (χ2/NDF = 6.73/6) by a power-law function with an index Γ = 2.15 ± 0.06stat ± 0.20sys while an F-test indicates that the power law with an exponential cut-offfunction provides a marginally better fit (χ2/NDF = 2.56/5) at the 2.1σ level. The source location is found to be consistent with the published radio location and its spatial extent is consistent with a point source.",

keywords = "Astroparticle physics, BL Lacertae objects: individual: 1ES 2344+514 = VER J2347+517, Gamma-rays: galaxies",

author = "C. Allen and S. Archambault and A. Archer and W. Benbow and R. Bird and E. Bourbeau and R. Brose and M. Buchovecky and Buckley, {J. H.} and V. Bugaev and Cardenzana, {J. V.} and M. Cerruti and X. Chen and Christiansen, {J. L.} and Connolly, {M. P.} and W. Cui and Daniel, {M. K.} and Eisch, {J. D.} and A. Falcone and Q. Feng and M. Fernandez-Alonso and Finley, {J. P.} and H. Fleischhack and A. Flinders and L. Fortson and A. Furniss and Gillanders, {G. H.} and S. Griffin and J. Grube and M. H{\"u}tten and N. H{\aa}kansson and D. Hanna and O. Hervet and J. Holder and G. Hughes and Humensky, {T. B.} and Johnson, {C. A.} and P. Kaaret and P. Kar and N. Kelley-Hoskins and M. Kertzman and D. Kieda and M. Krause and F. Krennrich and S. Kumar and Lang, {M. J.} and G. Maier and S. McArthur and A. McCann and K. Meagher and P. Moriarty and R. Mukherjee and T. Nguyen and D. Nieto and S. O'Brien and {O'Faol{\'a}in de Bhr{\'o}ithe}, A. and Ong, {R. A.} and Otte, {A. N.} and N. Park and A. Petrashyk and A. Pichel and M. Pohl and A. Popkow and E. Pueschel and J. Quinn and K. Ragan and Reynolds, {P. T.} and Richards, {G. T.} and E. Roache and Rovero, {A. C.} and C. Rulten and I. Sadeh and M. Santander and Sembroski, {G. H.} and K. Shahinyan and I. Telezhinsky and Tucci, {J. V.} and J. Tyler and Wakely, {S. P.} and A. Weinstein and A. Wilhelm and Williams, {D. A.}",

note = "Funding Information: This research is supported by grants from the U.S. Department of Energy Office of Science, the U.S. National Science Foundation and the Smithsonian Institution, and by NSERC in Canada. We acknowledge the excellent work of the technical support staffat the Fred Lawrence Whipple Observatory and at the collaborating institutions in the construction and operation of the instrument. S. O'Brien is funded by a UCD Research Scholarship. The VERITAS Collaboration is grateful to TrevorWeekes for his seminal contributions and leadership in the field of VHE gamma-ray astrophysics, which made this study possible. Publisher Copyright: {\textcopyright} 2017 The Authors.",

year = "2017",

month = oct,

doi = "10.1093/mnras/stx1756",

language = "English (US)",

volume = "471",

pages = "2117--2123",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press",

number = "2",

}

TY - JOUR

T1 - Very-high-energy γ -ray observations of the Blazar 1ES 2344+514 with VERITAS

AU - Allen, C.

AU - Archambault, S.

AU - Archer, A.

AU - Benbow, W.

AU - Bird, R.

AU - Bourbeau, E.

AU - Brose, R.

AU - Buchovecky, M.

AU - Buckley, J. H.

AU - Bugaev, V.

AU - Cardenzana, J. V.

AU - Cerruti, M.

AU - Chen, X.

AU - Christiansen, J. L.

AU - Connolly, M. P.

AU - Cui, W.

AU - Daniel, M. K.

AU - Eisch, J. D.

AU - Falcone, A.

AU - Feng, Q.

AU - Fernandez-Alonso, M.

AU - Finley, J. P.

AU - Fleischhack, H.

AU - Flinders, A.

AU - Fortson, L.

AU - Furniss, A.

AU - Gillanders, G. H.

AU - Griffin, S.

AU - Grube, J.

AU - Hütten, M.

AU - Håkansson, N.

AU - Hanna, D.

AU - Hervet, O.

AU - Holder, J.

AU - Hughes, G.

AU - Humensky, T. B.

AU - Johnson, C. A.

AU - Kaaret, P.

AU - Kar, P.

AU - Kelley-Hoskins, N.

AU - Kertzman, M.

AU - Kieda, D.

AU - Krause, M.

AU - Krennrich, F.

AU - Kumar, S.

AU - Lang, M. J.

AU - Maier, G.

AU - McArthur, S.

AU - McCann, A.

AU - Meagher, K.

AU - Moriarty, P.

AU - Mukherjee, R.

AU - Nguyen, T.

AU - Nieto, D.

AU - O'Brien, S.

AU - O'Faoláin de Bhróithe, A.

AU - Ong, R. A.

AU - Otte, A. N.

AU - Park, N.

AU - Petrashyk, A.

AU - Pichel, A.

AU - Pohl, M.

AU - Popkow, A.

AU - Pueschel, E.

AU - Quinn, J.

AU - Ragan, K.

AU - Reynolds, P. T.

AU - Richards, G. T.

AU - Roache, E.

AU - Rovero, A. C.

AU - Rulten, C.

AU - Sadeh, I.

AU - Santander, M.

AU - Sembroski, G. H.

AU - Shahinyan, K.

AU - Telezhinsky, I.

AU - Tucci, J. V.

AU - Tyler, J.

AU - Wakely, S. P.

AU - Weinstein, A.

AU - Wilhelm, A.

AU - Williams, D. A.

N1 - Funding Information: This research is supported by grants from the U.S. Department of Energy Office of Science, the U.S. National Science Foundation and the Smithsonian Institution, and by NSERC in Canada. We acknowledge the excellent work of the technical support staffat the Fred Lawrence Whipple Observatory and at the collaborating institutions in the construction and operation of the instrument. S. O'Brien is funded by a UCD Research Scholarship. The VERITAS Collaboration is grateful to TrevorWeekes for his seminal contributions and leadership in the field of VHE gamma-ray astrophysics, which made this study possible. Publisher Copyright: © 2017 The Authors.

PY - 2017/10

Y1 - 2017/10

N2 - We present very-high-energy γ -ray observations of the BL Lac object 1ES 2344+514 taken by the Very Energetic Radiation Imaging Telescope Array System between 2007 and 2015. 1ES 2344+514 is detected with a statistical significance above the background of 20.8σ in 47.2 h (livetime) of observations, making this the most comprehensive very-high-energy study of 1ES 2344+514 to date. Using these observations, the temporal properties of 1ES 2344+514 are studied on short and long times-scales. We fit a constant-flux model to nightly and seasonally binned light curves and apply a fractional variability test to determine the stability of the source on different time-scales. We reject the constant-flux model for the 2007-2008 and 2014-2015 nightly binned light curves and for the long-term seasonally binned light curve at the > 3σ level. The spectra of the time-averaged emission before and after correction for attenuation by the extragalactic background light are obtained. The observed time-averaged spectrum above 200 GeV is satisfactorily fitted (χ2/NDF = 7.89/6) by a power-law function with an index Γ = 2.46 ± 0.06stat ± 0.20sys and extends to at least 8 TeV. The extragalactic-backgroundlight- deabsorbed spectrum is adequately fit (χ2/NDF = 6.73/6) by a power-law function with an index Γ = 2.15 ± 0.06stat ± 0.20sys while an F-test indicates that the power law with an exponential cut-offfunction provides a marginally better fit (χ2/NDF = 2.56/5) at the 2.1σ level. The source location is found to be consistent with the published radio location and its spatial extent is consistent with a point source.

AB - We present very-high-energy γ -ray observations of the BL Lac object 1ES 2344+514 taken by the Very Energetic Radiation Imaging Telescope Array System between 2007 and 2015. 1ES 2344+514 is detected with a statistical significance above the background of 20.8σ in 47.2 h (livetime) of observations, making this the most comprehensive very-high-energy study of 1ES 2344+514 to date. Using these observations, the temporal properties of 1ES 2344+514 are studied on short and long times-scales. We fit a constant-flux model to nightly and seasonally binned light curves and apply a fractional variability test to determine the stability of the source on different time-scales. We reject the constant-flux model for the 2007-2008 and 2014-2015 nightly binned light curves and for the long-term seasonally binned light curve at the > 3σ level. The spectra of the time-averaged emission before and after correction for attenuation by the extragalactic background light are obtained. The observed time-averaged spectrum above 200 GeV is satisfactorily fitted (χ2/NDF = 7.89/6) by a power-law function with an index Γ = 2.46 ± 0.06stat ± 0.20sys and extends to at least 8 TeV. The extragalactic-backgroundlight- deabsorbed spectrum is adequately fit (χ2/NDF = 6.73/6) by a power-law function with an index Γ = 2.15 ± 0.06stat ± 0.20sys while an F-test indicates that the power law with an exponential cut-offfunction provides a marginally better fit (χ2/NDF = 2.56/5) at the 2.1σ level. The source location is found to be consistent with the published radio location and its spatial extent is consistent with a point source.

KW - Astroparticle physics

KW - BL Lacertae objects: individual: 1ES 2344+514 = VER J2347+517

KW - Gamma-rays: galaxies

UR - http://www.scopus.com/inward/record.url?scp=85052528946&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85052528946&partnerID=8YFLogxK

U2 - 10.1093/mnras/stx1756

DO - 10.1093/mnras/stx1756

M3 - Article

AN - SCOPUS:85052528946

SN - 0035-8711

VL - 471

SP - 2117

EP - 2123

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 2

ER -

Very-high-energy γ -ray observations of the Blazar 1ES 2344+514 with VERITAS

Abstract

Bibliographical note

Keywords

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