Deep broadband observations of the distant gamma-ray blazar PKS 1424+240

S. Archambault; T. Aune; B. Behera; M. Beilicke; W. Benbow; K. Berger; R. Bird; J. Biteau; V. Bugaev; K. Byrum; J. V. Cardenzana; M. Cerruti; X. Chen; L. Ciupik; M. P. Connolly; W. Cui; J. Dumm; M. Errando; A. Falcone; S. Federici; Q. Feng; J. P. Finley; H. Fleischhack; L. Fortson; A. Furniss; N. Galante; G. H. Gillanders; S. Griffin; S. T. Griffiths; J. Grube; G. Gyuk; D. Hanna; J. Holder; G. Hughes; T. B. Humensky; C. A. Johnson; P. Kaaret; M. Kertzman; Y. Khassen; D. Kieda; H. Krawczynski; F. Krennrich; S. Kumar; M. J. Lang; A. S. Madhavan; G. Maier; A. McCann; K. Meagher; P. Moriarty; R. Mukherjee; D. Nieto; A. O Faoláin De Bhróithe; R. A. Ong; A. N. Otte; N. Park; M. Pohl; A. Popkow; H. Prokoph; J. Quinn; K. Ragan; J. Rajotte; L. C. Reyes; P. T. Reynolds; G. T. Richards; E. Roache; G. H. Sembroski; K. Shahinyan; D. Staszak; I. Telezhinsky; J. V. Tucci; J. Tyler; A. Varlotta; V. V. Vassiliev; S. Vincent; S. P. Wakely; A. Weinstein; R. Welsing; A. Wilhelm; D. A. Williams; M. Ackermann; M. Ajello; A. Albert; L. Baldini; D. Bastieri; R. Bellazzini; E. Bissaldi; J. Bregeon; R. Buehler; S. Buson; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; E. Cavazzuti; E. Charles; J. Chiang; S. Ciprini; R. Claus; S. Cutini; F. D'Ammando; A. De Angelis; F. De Palma; C. D. Dermer; S. W. Digel; L. Di Venere; P. S. Drell; C. Favuzzi; A. Franckowiak; P. Fusco; F. Gargano; D. Gasparrini; N. Giglietto; F. Giordano; M. Giroletti; I. A. Grenier; S. Guiriec; T. Jogler; M. Kuss; S. Larsson; L. Latronico; F. Longo; F. Loparco; P. Lubrano; G. M. Madejski; M. Mayer; M. N. Mazziotta; P. F. Michelson; T. Mizuno; M. E. Monzani; A. Morselli; S. Murgia; E. Nuss; T. Ohsugi; J. F. Ormes; D. Paneque; J. S. Perkins; F. Piron; G. Pivato; S. Rainò; M. Razzano; A. Reimer; O. Reimer; S. Ritz; M. Schaal; C. Sgrò; E. J. Siskind; P. Spinelli; H. Takahashi; L. Tibaldo; M. Tinivella; E. Troja; G. Vianello; M. Werner; M. Wood

doi:10.1088/2041-8205/785/1/L16

Deep broadband observations of the distant gamma-ray blazar PKS 1424+240

S. Archambault, T. Aune, B. Behera, M. Beilicke, W. Benbow, K. Berger, R. Bird, J. Biteau, V. Bugaev, K. Byrum, J. V. Cardenzana, M. Cerruti, X. Chen, L. Ciupik, M. P. Connolly, W. Cui, J. Dumm, M. Errando, A. Falcone, S. FedericiQ. Feng, J. P. Finley, H. Fleischhack, L. Fortson, A. Furniss, N. Galante, G. H. Gillanders, S. Griffin, S. T. Griffiths, J. Grube, G. Gyuk, D. Hanna, J. Holder, G. Hughes, T. B. Humensky, C. A. Johnson, P. Kaaret, M. Kertzman, Y. Khassen, D. Kieda, H. Krawczynski, F. Krennrich, S. Kumar, M. J. Lang, A. S. Madhavan, G. Maier, A. McCann, K. Meagher, P. Moriarty, R. Mukherjee, D. Nieto, A. O Faoláin De Bhróithe, R. A. Ong, A. N. Otte, N. Park, M. Pohl, A. Popkow, H. Prokoph, J. Quinn, K. Ragan, J. Rajotte, L. C. Reyes, P. T. Reynolds, G. T. Richards, E. Roache, G. H. Sembroski, K. Shahinyan, D. Staszak, I. Telezhinsky, J. V. Tucci, J. Tyler, A. Varlotta, V. V. Vassiliev, S. Vincent, S. P. Wakely, A. Weinstein, R. Welsing, A. Wilhelm, D. A. Williams, M. Ackermann, M. Ajello, A. Albert, L. Baldini, D. Bastieri, R. Bellazzini, E. Bissaldi, J. Bregeon, R. Buehler, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, E. Cavazzuti, E. Charles, J. Chiang, S. Ciprini, R. Claus, S. Cutini, F. D'Ammando, A. De Angelis, F. De Palma, C. D. Dermer, S. W. Digel, L. Di Venere, P. S. Drell, C. Favuzzi, A. Franckowiak, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, I. A. Grenier, S. Guiriec, T. Jogler, M. Kuss, S. Larsson, L. Latronico, F. Longo, F. Loparco, P. Lubrano, G. M. Madejski, M. Mayer, M. N. Mazziotta, P. F. Michelson, T. Mizuno, M. E. Monzani, A. Morselli, S. Murgia, E. Nuss, T. Ohsugi, J. F. Ormes, D. Paneque, J. S. Perkins, F. Piron, G. Pivato, S. Rainò, M. Razzano, A. Reimer, O. Reimer, S. Ritz, M. Schaal, C. Sgrò, E. J. Siskind, P. Spinelli, H. Takahashi, L. Tibaldo, M. Tinivella, E. Troja, G. Vianello, M. Werner, M. Wood

Physics and Astronomy (Twin Cities)

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Abstract

We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope, and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of z ≥ 0.6035, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hr of VERITAS observations over three years, a multiwavelength light curve, and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1 ± 0.3) × 10^-7 photons m^-2 s ^-1 above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02 ± 0.08) × 10^-7 photons m^-2 s^-1 above 120 GeV. The measured differential very high energy (VHE; E ≥ 100 GeV) spectral indices are Γ = 3.8 ± 0.3, 4.3 ± 0.6 and 4.5 ± 0.2 in 2009, 2011, and 2013, respectively. No significant spectral change across the observation epochs is detected. We find no evidence for variability at gamma-ray opacities of greater than τ = 2, where it is postulated that any variability would be small and occur on timescales longer than a year if hadronic cosmic-ray interactions with extragalactic photon fields provide a secondary VHE photon flux. The data cannot rule out such variability due to low statistics.

Original language	English (US)
Article number	785
Journal	Astrophysical Journal Letters
Volume	785
Issue number	1
DOIs	https://doi.org/10.1088/2041-8205/785/1/L16
State	Published - Apr 10 2014

Keywords

BL Lacertae objects
galaxies

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10.1088/2041-8205/785/1/L16

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Archambault, S., Aune, T., Behera, B., Beilicke, M., Benbow, W., Berger, K., Bird, R., Biteau, J., Bugaev, V., Byrum, K., Cardenzana, J. V., Cerruti, M., Chen, X., Ciupik, L., Connolly, M. P., Cui, W., Dumm, J., Errando, M., Falcone, A., ... Wood, M. (2014). Deep broadband observations of the distant gamma-ray blazar PKS 1424+240. Astrophysical Journal Letters, 785(1), Article 785. https://doi.org/10.1088/2041-8205/785/1/L16

Archambault, S, Aune, T, Behera, B, Beilicke, M, Benbow, W, Berger, K, Bird, R, Biteau, J, Bugaev, V, Byrum, K, Cardenzana, JV, Cerruti, M, Chen, X, Ciupik, L, Connolly, MP, Cui, W, Dumm, J, Errando, M, Falcone, A, Federici, S, Feng, Q, Finley, JP, Fleischhack, H, Fortson, L, Furniss, A, Galante, N, Gillanders, GH, Griffin, S, Griffiths, ST, Grube, J, Gyuk, G, Hanna, D, Holder, J, Hughes, G, Humensky, TB, Johnson, CA, Kaaret, P, Kertzman, M, Khassen, Y, Kieda, D, Krawczynski, H, Krennrich, F, Kumar, S, Lang, MJ, Madhavan, AS, Maier, G, McCann, A, Meagher, K, Moriarty, P, Mukherjee, R, Nieto, D, De Bhróithe, AOF, Ong, RA, Otte, AN, Park, N, Pohl, M, Popkow, A, Prokoph, H, Quinn, J, Ragan, K, Rajotte, J, Reyes, LC, Reynolds, PT, Richards, GT, Roache, E, Sembroski, GH, Shahinyan, K, Staszak, D, Telezhinsky, I, Tucci, JV, Tyler, J, Varlotta, A, Vassiliev, VV, Vincent, S, Wakely, SP, Weinstein, A, Welsing, R, Wilhelm, A, Williams, DA, Ackermann, M, Ajello, M, Albert, A, Baldini, L, Bastieri, D, Bellazzini, R, Bissaldi, E, Bregeon, J, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cavazzuti, E, Charles, E, Chiang, J, Ciprini, S, Claus, R, Cutini, S, D'Ammando, F, De Angelis, A, De Palma, F, Dermer, CD, Digel, SW, Di Venere, L, Drell, PS, Favuzzi, C, Franckowiak, A, Fusco, P, Gargano, F, Gasparrini, D, Giglietto, N, Giordano, F, Giroletti, M, Grenier, IA, Guiriec, S, Jogler, T, Kuss, M, Larsson, S, Latronico, L, Longo, F, Loparco, F, Lubrano, P, Madejski, GM, Mayer, M, Mazziotta, MN, Michelson, PF, Mizuno, T, Monzani, ME, Morselli, A, Murgia, S, Nuss, E, Ohsugi, T, Ormes, JF, Paneque, D, Perkins, JS, Piron, F, Pivato, G, Rainò, S, Razzano, M, Reimer, A, Reimer, O, Ritz, S, Schaal, M, Sgrò, C, Siskind, EJ, Spinelli, P, Takahashi, H, Tibaldo, L, Tinivella, M, Troja, E, Vianello, G, Werner, M & Wood, M 2014, 'Deep broadband observations of the distant gamma-ray blazar PKS 1424+240', Astrophysical Journal Letters, vol. 785, no. 1, 785. https://doi.org/10.1088/2041-8205/785/1/L16

@article{0da3b7fc11954aefbfbaa324b4543277,

title = "Deep broadband observations of the distant gamma-ray blazar PKS 1424+240",

abstract = "We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope, and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of z ≥ 0.6035, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hr of VERITAS observations over three years, a multiwavelength light curve, and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1 ± 0.3) × 10-7 photons m-2 s -1 above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02 ± 0.08) × 10-7 photons m-2 s-1 above 120 GeV. The measured differential very high energy (VHE; E ≥ 100 GeV) spectral indices are Γ = 3.8 ± 0.3, 4.3 ± 0.6 and 4.5 ± 0.2 in 2009, 2011, and 2013, respectively. No significant spectral change across the observation epochs is detected. We find no evidence for variability at gamma-ray opacities of greater than τ = 2, where it is postulated that any variability would be small and occur on timescales longer than a year if hadronic cosmic-ray interactions with extragalactic photon fields provide a secondary VHE photon flux. The data cannot rule out such variability due to low statistics.",

keywords = "BL Lacertae objects, galaxies",

author = "S. Archambault and T. Aune and B. Behera and M. Beilicke and W. Benbow and K. Berger and R. Bird and J. Biteau and V. Bugaev and K. Byrum and Cardenzana, {J. V.} and M. Cerruti and X. Chen and L. Ciupik and Connolly, {M. P.} and W. Cui and J. Dumm and M. Errando and A. Falcone and S. Federici and Q. Feng and Finley, {J. P.} and H. Fleischhack 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 D. Hanna and J. Holder and G. Hughes and Humensky, {T. B.} and Johnson, {C. A.} and P. Kaaret and M. Kertzman and Y. Khassen and D. Kieda and H. Krawczynski and F. Krennrich and S. Kumar and Lang, {M. J.} and Madhavan, {A. S.} and G. Maier and A. McCann and K. Meagher and P. Moriarty and R. Mukherjee and D. Nieto and {De Bhr{\'o}ithe}, {A. O Faol{\'a}in} and Ong, {R. A.} and Otte, {A. N.} and N. Park and M. Pohl and A. Popkow and H. Prokoph and J. Quinn and K. Ragan and J. Rajotte and Reyes, {L. C.} and Reynolds, {P. T.} and Richards, {G. T.} and E. Roache and Sembroski, {G. H.} and K. Shahinyan and D. Staszak and I. Telezhinsky and Tucci, {J. V.} and J. Tyler and A. Varlotta and Vassiliev, {V. V.} and S. Vincent and Wakely, {S. P.} and A. Weinstein and R. Welsing and A. Wilhelm and Williams, {D. A.} and M. Ackermann and M. Ajello and A. Albert and L. Baldini and D. Bastieri and R. Bellazzini and E. Bissaldi and J. Bregeon and R. Buehler and S. Buson and Caliandro, {G. A.} and Cameron, {R. A.} and Caraveo, {P. A.} and E. Cavazzuti and E. Charles and J. Chiang and S. Ciprini and R. Claus and S. Cutini and F. D'Ammando and {De Angelis}, A. and {De Palma}, F. and Dermer, {C. D.} and Digel, {S. W.} and {Di Venere}, L. and Drell, {P. S.} and C. Favuzzi and A. Franckowiak and P. Fusco and F. Gargano and D. Gasparrini and N. Giglietto and F. Giordano and M. Giroletti and Grenier, {I. A.} and S. Guiriec and T. Jogler and M. Kuss and S. Larsson and L. Latronico and F. Longo and F. Loparco and P. Lubrano and Madejski, {G. M.} and M. Mayer and Mazziotta, {M. N.} and Michelson, {P. F.} and T. Mizuno and Monzani, {M. E.} and A. Morselli and S. Murgia and E. Nuss and T. Ohsugi and Ormes, {J. F.} and D. Paneque and Perkins, {J. S.} and F. Piron and G. Pivato and S. Rain{\`o} and M. Razzano and A. Reimer and O. Reimer and S. Ritz and M. Schaal and C. Sgr{\`o} and Siskind, {E. J.} and P. Spinelli and H. Takahashi and L. Tibaldo and M. Tinivella and E. Troja and G. Vianello and M. Werner and M. Wood",

year = "2014",

month = apr,

day = "10",

doi = "10.1088/2041-8205/785/1/L16",

language = "English (US)",

volume = "785",

journal = "Astrophysical Journal Letters",

issn = "2041-8205",

publisher = "IOP Publishing Ltd.",

number = "1",

}

TY - JOUR

T1 - Deep broadband observations of the distant gamma-ray blazar PKS 1424+240

AU - Archambault, S.

AU - Aune, T.

AU - Behera, B.

AU - Beilicke, M.

AU - Benbow, W.

AU - Berger, K.

AU - Bird, R.

AU - Biteau, J.

AU - Bugaev, V.

AU - Byrum, K.

AU - Cardenzana, J. V.

AU - Cerruti, M.

AU - Chen, X.

AU - Ciupik, L.

AU - Connolly, M. P.

AU - Cui, W.

AU - Dumm, J.

AU - Errando, M.

AU - Falcone, A.

AU - Federici, S.

AU - Feng, Q.

AU - Finley, J. P.

AU - Fleischhack, H.

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 - Hanna, D.

AU - Holder, J.

AU - Hughes, G.

AU - Humensky, T. B.

AU - Johnson, C. A.

AU - Kaaret, P.

AU - Kertzman, M.

AU - Khassen, Y.

AU - Kieda, D.

AU - Krawczynski, H.

AU - Krennrich, F.

AU - Kumar, S.

AU - Lang, M. J.

AU - Madhavan, A. S.

AU - Maier, G.

AU - McCann, A.

AU - Meagher, K.

AU - Moriarty, P.

AU - Mukherjee, R.

AU - Nieto, D.

AU - De Bhróithe, A. O Faoláin

AU - Ong, R. A.

AU - Otte, A. N.

AU - Park, N.

AU - Pohl, M.

AU - Popkow, A.

AU - Prokoph, H.

AU - Quinn, J.

AU - Ragan, K.

AU - Rajotte, J.

AU - Reyes, L. C.

AU - Reynolds, P. T.

AU - Richards, G. T.

AU - Roache, E.

AU - Sembroski, G. H.

AU - Shahinyan, K.

AU - Staszak, D.

AU - Telezhinsky, I.

AU - Tucci, J. V.

AU - Tyler, J.

AU - Varlotta, A.

AU - Vassiliev, V. V.

AU - Vincent, S.

AU - Wakely, S. P.

AU - Weinstein, A.

AU - Welsing, R.

AU - Wilhelm, A.

AU - Williams, D. A.

AU - Ackermann, M.

AU - Ajello, M.

AU - Albert, A.

AU - Baldini, L.

AU - Bastieri, D.

AU - Bellazzini, R.

AU - Bissaldi, E.

AU - Bregeon, J.

AU - Buehler, R.

AU - Buson, S.

AU - Caliandro, G. A.

AU - Cameron, R. A.

AU - Caraveo, P. A.

AU - Cavazzuti, E.

AU - Charles, E.

AU - Chiang, J.

AU - Ciprini, S.

AU - Claus, R.

AU - Cutini, S.

AU - D'Ammando, F.

AU - De Angelis, A.

AU - De Palma, F.

AU - Dermer, C. D.

AU - Digel, S. W.

AU - Di Venere, L.

AU - Drell, P. S.

AU - Favuzzi, C.

AU - Franckowiak, A.

AU - Fusco, P.

AU - Gargano, F.

AU - Gasparrini, D.

AU - Giglietto, N.

AU - Giordano, F.

AU - Giroletti, M.

AU - Grenier, I. A.

AU - Guiriec, S.

AU - Jogler, T.

AU - Kuss, M.

AU - Larsson, S.

AU - Latronico, L.

AU - Longo, F.

AU - Loparco, F.

AU - Lubrano, P.

AU - Madejski, G. M.

AU - Mayer, M.

AU - Mazziotta, M. N.

AU - Michelson, P. F.

AU - Mizuno, T.

AU - Monzani, M. E.

AU - Morselli, A.

AU - Murgia, S.

AU - Nuss, E.

AU - Ohsugi, T.

AU - Ormes, J. F.

AU - Paneque, D.

AU - Perkins, J. S.

AU - Piron, F.

AU - Pivato, G.

AU - Rainò, S.

AU - Razzano, M.

AU - Reimer, A.

AU - Reimer, O.

AU - Ritz, S.

AU - Schaal, M.

AU - Sgrò, C.

AU - Siskind, E. J.

AU - Spinelli, P.

AU - Takahashi, H.

AU - Tibaldo, L.

AU - Tinivella, M.

AU - Troja, E.

AU - Vianello, G.

AU - Werner, M.

AU - Wood, M.

PY - 2014/4/10

Y1 - 2014/4/10

N2 - We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope, and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of z ≥ 0.6035, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hr of VERITAS observations over three years, a multiwavelength light curve, and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1 ± 0.3) × 10-7 photons m-2 s -1 above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02 ± 0.08) × 10-7 photons m-2 s-1 above 120 GeV. The measured differential very high energy (VHE; E ≥ 100 GeV) spectral indices are Γ = 3.8 ± 0.3, 4.3 ± 0.6 and 4.5 ± 0.2 in 2009, 2011, and 2013, respectively. No significant spectral change across the observation epochs is detected. We find no evidence for variability at gamma-ray opacities of greater than τ = 2, where it is postulated that any variability would be small and occur on timescales longer than a year if hadronic cosmic-ray interactions with extragalactic photon fields provide a secondary VHE photon flux. The data cannot rule out such variability due to low statistics.

AB - We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope, and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of z ≥ 0.6035, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hr of VERITAS observations over three years, a multiwavelength light curve, and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1 ± 0.3) × 10-7 photons m-2 s -1 above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02 ± 0.08) × 10-7 photons m-2 s-1 above 120 GeV. The measured differential very high energy (VHE; E ≥ 100 GeV) spectral indices are Γ = 3.8 ± 0.3, 4.3 ± 0.6 and 4.5 ± 0.2 in 2009, 2011, and 2013, respectively. No significant spectral change across the observation epochs is detected. We find no evidence for variability at gamma-ray opacities of greater than τ = 2, where it is postulated that any variability would be small and occur on timescales longer than a year if hadronic cosmic-ray interactions with extragalactic photon fields provide a secondary VHE photon flux. The data cannot rule out such variability due to low statistics.

KW - BL Lacertae objects

KW - galaxies

UR - http://www.scopus.com/inward/record.url?scp=84897391193&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84897391193&partnerID=8YFLogxK

U2 - 10.1088/2041-8205/785/1/L16

DO - 10.1088/2041-8205/785/1/L16

M3 - Article

AN - SCOPUS:84897391193

SN - 2041-8205

VL - 785

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

IS - 1

M1 - 785

ER -

Deep broadband observations of the distant gamma-ray blazar PKS 1424+240

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