Multiwavelength Observations of the Very High Energy Blazar 1ES 2344+514

• Published in: The Astrophysical journal Vol. 738; no. 2; pp. 169 - jQuery1323903887270='48'
• Main Authors: Acciari, V. A, 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, S. J, Finley, J. P, Fortin, P, Fortson, L. F, Furniss, A, Gall, D, Gillanders, G. H, Grube, J, Guenette, R, Gyuk, G, Hanna, D, Holder, J, Horan, D, Hui, C. M, Humensky, T. B, Imran, A, Kaaret, P, Karlsson, N, Kertzman, M, Kieda, D, Kildea, J, Konopelko, A, Krawczynski, H, Krennrich, F, Lang, M. J, LeBohec, S, Maier, G, Moriarty, P, Mukherjee, R, Ong, R. A, Otte, A. N, Pandel, D, Perkins, J. S, Pichel, A, Pohl, M, Quinn, J, Ragan, K, Reynolds, P. T, Rose, H. J, Schroedter, M, Sembroski, G. H, Smith, A. W, Steele, D, Swordy, S. P, Theiling, M, Toner, J. A, Varlotta, A, Vassiliev, V. V, Vincent, S, Wagner, R, Wakely, S. P, Ward, J. E, Weekes, T. C, Weinstein, A, Weisgarber, T, Williams, D. A, Wissel, S, Wood, M, Zitzer, B
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 10.09.2011; IOP
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Correlation coefficient; Crab nebula; Variability; Spectral energy distribution; Blazar; BL Lacertae objects; Correlations; Cosmic radio sources; Multifrequency observation; Models; Modelling; Power law; Very high energy; individual (IES 2344+514)
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/738/2/169

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) Delta *g-ray, X-ray, and UV energies. Observations with VERITAS in VHE Delta *g-rays yield a strong detection of 20 Delta *s with 633 excess events in a total exposure of 18.1 hr live time. A strong VHE Delta *g-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 Delta *G = 2.78 ? 0.09stat ? 0.15syst. On the flaring night of 2007 December 7 the measured VHE Delta *g-ray photon index was Delta *G = 2.43 ? 0.22stat ? 0.15syst. 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 ~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 Delta *g-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.