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

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 20{sigma} 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{sup -11} photons cm{sup -2} s{sup -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{sup -11} photons cm{sup -2} s{sup -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 {Gamma} = 2.78 {+-} 0.09{sub stat} {+-} 0.15{sub syst}. On the flaring night of 2007 December 7 the measured VHE {gamma}-ray photon index was {Gamma} = 2.43 {+-} 0.22{sub stat} {+-} 0.15{sub syst}. Over the fullmore » 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 {approx}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{sup -11} erg cm{sup -2} s{sup -1}. Evidence for a correlation between the X-ray flux and VHE {gamma}-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.« less

Authors:
;  [1]; ;  [2]; ;  [3]; ;  [4]; ; ;  [5];  [6]; ;  [7];  [8];  [9];  [10]; ;  [11];  [12]
  1. Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States)
  2. Department of Physics and Astronomy and the Bartol Research Institute, University of Delaware, Newark, DE 19716 (United States)
  3. Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)
  4. Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States)
  5. Department of Physics, Washington University, St. Louis, MO 63130 (United States)
  6. School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)
  7. Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States)
  8. Physics Department, McGill University, Montreal, QC H3A 2T8 (Canada)
  9. Physics Department, University of Utah, Salt Lake City, UT 84112 (United States)
  10. Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States)
  11. Department of Physics, Purdue University, West Lafayette, IN 47907 (United States)
  12. Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States)
Publication Date:
OSTI Identifier:
21584860
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 738; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/738/2/169; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BL LACERTAE OBJECTS; CRAB NEBULA; ENERGY SPECTRA; GAMMA RADIATION; PHOTONS; SIMULATION; X RADIATION; BOSONS; COSMIC RADIO SOURCES; ELECTROMAGNETIC RADIATION; ELEMENTARY PARTICLES; IONIZING RADIATIONS; MASSLESS PARTICLES; NEBULAE; RADIATIONS; SPECTRA; SUPERNOVA REMNANTS

Citation Formats

Acciari, V A, Benbow, W, Aliu, E, Boltuch, D, Arlen, T, Fegan, S J, Aune, T, Furniss, A, Beilicke, M, Bugaev, V, Dickherber, R, Cannon, A, Ciupik, L, Fortson, L F, Cogan, P, Colin, P, Falcone, A, Finley, J P, Gall, D, and Fortin, P. MULTIWAVELENGTH OBSERVATIONS OF THE VERY HIGH ENERGY BLAZAR 1ES 2344+514. United States: N. p., 2011. Web. doi:10.1088/0004-637X/738/2/169; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Acciari, V A, Benbow, W, Aliu, E, Boltuch, D, Arlen, T, Fegan, S J, Aune, T, Furniss, A, Beilicke, M, Bugaev, V, Dickherber, R, Cannon, A, Ciupik, L, Fortson, L F, Cogan, P, Colin, P, Falcone, A, Finley, J P, Gall, D, & Fortin, P. MULTIWAVELENGTH OBSERVATIONS OF THE VERY HIGH ENERGY BLAZAR 1ES 2344+514. United States. https://doi.org/10.1088/0004-637X/738/2/169; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Acciari, V A, Benbow, W, Aliu, E, Boltuch, D, Arlen, T, Fegan, S J, Aune, T, Furniss, A, Beilicke, M, Bugaev, V, Dickherber, R, Cannon, A, Ciupik, L, Fortson, L F, Cogan, P, Colin, P, Falcone, A, Finley, J P, Gall, D, and Fortin, P. 2011. "MULTIWAVELENGTH OBSERVATIONS OF THE VERY HIGH ENERGY BLAZAR 1ES 2344+514". United States. https://doi.org/10.1088/0004-637X/738/2/169; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@article{osti_21584860,
title = {MULTIWAVELENGTH OBSERVATIONS OF THE VERY HIGH ENERGY BLAZAR 1ES 2344+514},
author = {Acciari, V A and Benbow, W and Aliu, E and Boltuch, D and Arlen, T and Fegan, S J and Aune, T and Furniss, A and Beilicke, M and Bugaev, V and Dickherber, R and Cannon, A and Ciupik, L and Fortson, L F and Cogan, P and Colin, P and Falcone, A and Finley, J P and Gall, D and Fortin, P},
abstractNote = {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 20{sigma} 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{sup -11} photons cm{sup -2} s{sup -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{sup -11} photons cm{sup -2} s{sup -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 {Gamma} = 2.78 {+-} 0.09{sub stat} {+-} 0.15{sub syst}. On the flaring night of 2007 December 7 the measured VHE {gamma}-ray photon index was {Gamma} = 2.43 {+-} 0.22{sub stat} {+-} 0.15{sub 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 {approx}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{sup -11} erg cm{sup -2} s{sup -1}. Evidence for a correlation between the X-ray flux and VHE {gamma}-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.},
doi = {10.1088/0004-637X/738/2/169; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},
url = {https://www.osti.gov/biblio/21584860}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 738,
place = {United States},
year = {Sat Sep 10 00:00:00 EDT 2011},
month = {Sat Sep 10 00:00:00 EDT 2011}
}