MULTIWAVELENGTH OBSERVATIONS OF THE VERY HIGH ENERGY BLAZAR 1ES 2344+514

作者：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

来源：Astrophysical Journal, 2011, 738(2): 169.

DOI：10.1088/0004-637X/738/2/169

• BL Lacertae objects: individual (IES 2344+514)

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.

• 出版日期2011-9-10