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Title: Gamma-Ray Emission From Two Blazars Behind The Galactic Plane: B2013+370 And B2023+336

Abstract

B2013+370 and B2023+336 are two blazars at low-galactic latitude that were previously proposed to be the counterparts for the EGRET unidentified sources 3EG J2016+3657 and 3EG J2027+3429. Gamma-ray emission associated with the EGRET sources has been detected by the Fermi Gammaray Space Telescope, and the two sources, 1FGL J2015.7+3708 and 1FGL J2027.6+3335, have been classified as unidentified in the 1-year catalog. This analysis of the Fermi-LAT data collected during 31 months reveals that the 1FGL sources are spatially compatible with the blazars, and are significantly variable, supporting the hypothesis of extragalactic origin for the gamma-ray emission. The gammaray light curves are compared with 15 GHz radio light curves from the 40-m telescope at the Owens Valley Radio Observatory (OVRO). Simultaneous variability is seen in both bands for the two blazar candidates. The study is completed with the X-ray analysis of 1FGL J2015.7+3708 using Swift observations that were triggered in August 2010 by a Fermi-detected are. The resulting spectral energy distribution shows a two-component structure typical of blazars. We also identify a second source in the field of view of 1FGL J2027.6+3335 with similar characteristics to the known LAT pulsars. This study gives solid evidence favoring blazar counterparts for these twomore » unidentified EGRET and Fermi sources, supporting the hypothesis that a number of unidentified gamma-ray sources at low galactic latitudes are indeed of extragalactic origin.« less

Authors:
 [1];  [1];  [2];  [1];  [3];  [4];  [5];  [1];  [2];  [2]
  1. Columbia Univ., New York, NY (United States)
  2. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  3. Ohio Univ., Athens, OH (United States)
  4. Ecole Polytechnique, Palaiseau (France)
  5. Columbia Univ., New York, NY (United States). Columbia Astrophysics Lab.
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1356760
Grant/Contract Number:  
AC02-76SF00515
Resource Type:
Accepted Manuscript
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 746; Journal Issue: 2; Journal ID: ISSN 0004-637X
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS

Citation Formats

Kara, E., Errando, M., Max-Moerbeck, W., Aliu, E., Böttcher, M., Fortin, P., Halpern, J. P., Mukherjee, R., Readhead, A. C. S., and Richards, J. L. Gamma-Ray Emission From Two Blazars Behind The Galactic Plane: B2013+370 And B2023+336. United States: N. p., 2012. Web. doi:10.1088/0004-637X/746/2/159.
Kara, E., Errando, M., Max-Moerbeck, W., Aliu, E., Böttcher, M., Fortin, P., Halpern, J. P., Mukherjee, R., Readhead, A. C. S., & Richards, J. L. Gamma-Ray Emission From Two Blazars Behind The Galactic Plane: B2013+370 And B2023+336. United States. doi:10.1088/0004-637X/746/2/159.
Kara, E., Errando, M., Max-Moerbeck, W., Aliu, E., Böttcher, M., Fortin, P., Halpern, J. P., Mukherjee, R., Readhead, A. C. S., and Richards, J. L. Thu . "Gamma-Ray Emission From Two Blazars Behind The Galactic Plane: B2013+370 And B2023+336". United States. doi:10.1088/0004-637X/746/2/159. https://www.osti.gov/servlets/purl/1356760.
@article{osti_1356760,
title = {Gamma-Ray Emission From Two Blazars Behind The Galactic Plane: B2013+370 And B2023+336},
author = {Kara, E. and Errando, M. and Max-Moerbeck, W. and Aliu, E. and Böttcher, M. and Fortin, P. and Halpern, J. P. and Mukherjee, R. and Readhead, A. C. S. and Richards, J. L.},
abstractNote = {B2013+370 and B2023+336 are two blazars at low-galactic latitude that were previously proposed to be the counterparts for the EGRET unidentified sources 3EG J2016+3657 and 3EG J2027+3429. Gamma-ray emission associated with the EGRET sources has been detected by the Fermi Gammaray Space Telescope, and the two sources, 1FGL J2015.7+3708 and 1FGL J2027.6+3335, have been classified as unidentified in the 1-year catalog. This analysis of the Fermi-LAT data collected during 31 months reveals that the 1FGL sources are spatially compatible with the blazars, and are significantly variable, supporting the hypothesis of extragalactic origin for the gamma-ray emission. The gammaray light curves are compared with 15 GHz radio light curves from the 40-m telescope at the Owens Valley Radio Observatory (OVRO). Simultaneous variability is seen in both bands for the two blazar candidates. The study is completed with the X-ray analysis of 1FGL J2015.7+3708 using Swift observations that were triggered in August 2010 by a Fermi-detected are. The resulting spectral energy distribution shows a two-component structure typical of blazars. We also identify a second source in the field of view of 1FGL J2027.6+3335 with similar characteristics to the known LAT pulsars. This study gives solid evidence favoring blazar counterparts for these two unidentified EGRET and Fermi sources, supporting the hypothesis that a number of unidentified gamma-ray sources at low galactic latitudes are indeed of extragalactic origin.},
doi = {10.1088/0004-637X/746/2/159},
journal = {Astrophysical Journal},
number = 2,
volume = 746,
place = {United States},
year = {2012},
month = {2}
}

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