- Main
DEEP BROADBAND OBSERVATIONS OF THE DISTANT GAMMA-RAY BLAZAR PKS 1424+240
- 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, A O'Faoláin;
- 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
- et al.
Published Web Location
https://doi.org/10.1088/2041-8205/785/1/l16Abstract
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. © 2014. The American Astronomical Society. All rights reserved..
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