TY - JOUR
T1 - Extreme blazars studied with Fermi-lat and Suzaku
T2 - 1es 0347-121 and blazar candidate HESS j1943+213
AU - Tanaka, Y. T.
AU - Stawarz,
AU - Finke, J.
AU - Cheung, C. C.
AU - Dermer, C. D.
AU - Kataoka, J.
AU - Bamba, A.
AU - Dubus, G.
AU - De Naurois, M.
AU - Wagner, S. J.
AU - Fukazawa, Y.
AU - Thompson, D. J.
PY - 2014/6/1
Y1 - 2014/6/1
N2 - We report on our study of high-energy properties of two peculiar TeV emitters: the "extreme blazar" 1ES 0347-121 and the "extreme blazar candidate" HESS J1943+213 located near the Galactic plane. Both objects are characterized by quiescent synchrotron emission with flat spectra extending up to the hard X-ray range, and both were reported to be missing GeV counterparts in the Fermi Large Area Telescope (LAT) two-year Source Catalog. We analyze a 4.5 yr accumulation of the Fermi-LAT data, resulting in the detection of 1ES 0347-121 in the GeV band, as well as in improved upper limits for HESS J1943+213. We also present the analysis results of newly acquired Suzaku data for HESS J1943+213. The X-ray spectrum is well represented by a single power law extending up to 25 keV with photon index 2.00 ± 0.02 and a moderate absorption in excess of the Galactic value, which is in agreement with previous X-ray observations. No short-term X-ray variability was found over the 80 ks duration of the Suzaku exposure. Under the blazar hypothesis, we modeled the spectral energy distributions of 1ES 0347-121 and HESS J1943+213, and we derived constraints on the intergalactic magnetic field strength and source energetics. We conclude that although the classification of HESS J1943+213 has not yet been determined, the blazar hypothesis remains the most plausible option since, in particular, the broadband spectra of the two analyzed sources along with the source model parameters closely resemble each other, and the newly available Wide-field Infrared Survey Explorer and UKIRT Infrared Deep Sky Survey data for HESS J1943+213 are consistent with the presence of an elliptical host at the distance of approximately ∼600 Mpc.
AB - We report on our study of high-energy properties of two peculiar TeV emitters: the "extreme blazar" 1ES 0347-121 and the "extreme blazar candidate" HESS J1943+213 located near the Galactic plane. Both objects are characterized by quiescent synchrotron emission with flat spectra extending up to the hard X-ray range, and both were reported to be missing GeV counterparts in the Fermi Large Area Telescope (LAT) two-year Source Catalog. We analyze a 4.5 yr accumulation of the Fermi-LAT data, resulting in the detection of 1ES 0347-121 in the GeV band, as well as in improved upper limits for HESS J1943+213. We also present the analysis results of newly acquired Suzaku data for HESS J1943+213. The X-ray spectrum is well represented by a single power law extending up to 25 keV with photon index 2.00 ± 0.02 and a moderate absorption in excess of the Galactic value, which is in agreement with previous X-ray observations. No short-term X-ray variability was found over the 80 ks duration of the Suzaku exposure. Under the blazar hypothesis, we modeled the spectral energy distributions of 1ES 0347-121 and HESS J1943+213, and we derived constraints on the intergalactic magnetic field strength and source energetics. We conclude that although the classification of HESS J1943+213 has not yet been determined, the blazar hypothesis remains the most plausible option since, in particular, the broadband spectra of the two analyzed sources along with the source model parameters closely resemble each other, and the newly available Wide-field Infrared Survey Explorer and UKIRT Infrared Deep Sky Survey data for HESS J1943+213 are consistent with the presence of an elliptical host at the distance of approximately ∼600 Mpc.
KW - X-rays: galaxies
KW - galaxies: active
KW - galaxies: jets
KW - gamma rays: galaxies
KW - radiation mechanisms: non-thermal
UR - http://www.scopus.com/inward/record.url?scp=84901029956&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84901029956&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/787/2/155
DO - 10.1088/0004-637X/787/2/155
M3 - Article
AN - SCOPUS:84901029956
SN - 0004-637X
VL - 787
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 155
ER -