Abstract
Multiwavelength observations of the high-frequency-peaked blazar 1ES 2344+514 were performed from 2007 October to 2008 January. The campaign represents the first contemporaneous data on the object at very high energy (VHE, E 100 GeV) gamma-ray, X-ray, and UV energies. Observations with VERITAS in VHE gamma-rays yield a strong detection of 20s with 633 excess events in a total exposure of 18.1 hr live time. A strong VHE gamma-ray flare on 2007 December 7 is measured at F( 300 GeV) = (6.76 + - 0.62) x 10(-11) photons cm(-2) s(-1), corresponding to 48% of the Crab Nebula flux. Excluding this flaring episode, nightly variability at lower fluxes is observed with a time-averaged mean of F( 300 GeV) = (1.06 + - 0.09) x 10(-11) photons cm(-2) s(-1) (7.6% of the Crab Nebula flux). The differential photon spectrum between 390 GeV and 8.3 TeV for the time-averaged observations excluding 2007 December 7 is well described by a power law with a photon index of G = 2.78 + - 0.09(stat) + - 0.15(syst). On the flaring night of 2007 December 7 the measured VHE gamma-ray photon index was Gamma = 2.43 + - 0.22(stat) + - 0.15(syst). Over the full period of VERITAS observations contemporaneous X-ray and UV data were taken with Swift and RXTE. The measured 2-10 keV flux ranged by a factor of similar to 7 during the campaign. On 2007 December 8 the highest ever observed X-ray flux from 1ES 2344+514 was measured by Swift X-ray Telescope at a flux of F(2-10 keV) = (6.28 + - 0.31) x 10(-11) erg cm(-2) s(-1). Evidence for a correlation between the X-ray flux and VHE. -ray flux on nightly timescales is indicated with a Pearson correlation coefficient of r = 0.60 + - 0.11. Contemporaneous spectral energy distributions (SEDs) of 1ES 2344+514 are presented for two distinct flux states. A one-zone synchrotron self-Compton (SSC) model describes both SEDs using parameters consistent with previous SSC modeling of 1ES 2344+514 from non-contemporaneous observations.
| Original language | English (Ireland) |
|---|---|
| Journal | Astrophysical Journal |
| Volume | 738 |
| Publication status | Published - 1 Sep 2011 |
Authors (Note for portal: view the doc link for the full list of authors)
- Authors
- Acciari, VA,Aliu, E,Arlen, T,Aune, T,Beilicke, M,Benbow, W,Boltuch, D,Bugaev, V,Cannon, A,Ciupik, L,Cogan, P,Colin, P,Dickherber, R,Falcone, A,Fegan, SJ,Finley, JP,Fortin, P,Fortson, LF,Furniss, A,Gall, D,Gillanders, GH,Grube, J,Guenette, R,Gyuk, G,Hanna, D,Holder, J,Horan, D,Hui, CM,Humensky, TB,Imran, A,Kaaret, P,Karlsson, N,Kertzman, M,Kieda, D,Kildea, J,Konopelko, A,Krawczynski, H,Krennrich, F,Lang, MJ,LeBohec, S,Maier, G,Moriarty, P,Mukherjee, R,Ong, RA,Otte, AN,Pandel, D,Perkins, JS,Pichel, A,Pohl, M,Quinn, J,Ragan, K,Reynolds, PT,Rose, HJ,Schroedter, M,Sembroski, GH,Smith, AW,Steele, D,Swordy, SP,Theiling, M,Toner, JA,Varlotta, A,Vassiliev, VV,Vincent, S,Wagner, R,Wakely, SP,Ward, JE,Weekes, TC,Weinstein, A,Weisgarber, T,Williams, DA,Wissel, S,Wood, M,Zitzer, B