期刊
ASTRONOMY & ASTROPHYSICS
卷 529, 期 -, 页码 -出版社
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201116545
关键词
galaxies: active; BL Lacertae objects: individual: IGR J19443+2117; gamma rays: general
资金
- German Ministry for Education and Research (BMBF)
- Max Planck Society
- French Ministry for Research
- CNRS-IN2P3
- CNRS
- U.K. Science and Technology Facilities Council (STFC)
- IPNP of the Charles University
- Polish Ministry of Science and Higher Education
- South African Department of Science and Technology
- National Research Foundation
- University of Namibia
- CAPES Foundation, Ministry of Education of Brazil
- Erasmus Mundus, External Cooperation Window
- European Community [ERC-StG-200911]
- Science and Technology Facilities Council [ST/F002963/1, ST/I001573/1, PP/E001319/1, PP/E001645/2] Funding Source: researchfish
Context. The H. E. S. S. Cherenkov telescope array has been surveying the Galactic plane for new VHE (>100 GeV) gamma-ray sources. Aims. We report on a newly detected point-like source, HESS J1943+213. This source coincides with an unidentified hard X-ray source IGR J19443+2117, which was proposed to have radio and infrared counterparts. Methods. We combine new H. E. S. S., Fermi/LAT and Nancay Radio Telescope observations with pre-existing non-simultaneous multi-wavelength observations of IGR J19443+2117 and discuss the likely source associations as well as the interpretation as an active galactic nucleus, a gamma-ray binary or a pulsar wind nebula. Results. HESS J1943+213 is detected at the significance level of 7.9 sigma (post-trials) at RA(J2000) = 19(h)43(m)55(s) +/- 1(stat)(s) +/- 1(sys)(s), Dec(J2000) = +21 degrees 18'8 '' +/- 17(stat)'' +/- 20(sys)''. The source has a soft spectrum with photon index Gamma = 3.1 +/- 0.3(stat) +/- 0.2(sys) and a flux above 470 GeV of (1.3 +/- 0.2(stat) +/- 0.3(sys)) x 10(-12) cm(-2) s(-1). There is no Fermi/LAT counterpart down to a flux limit of 6 x 10(-9) cm(-2) s(-1) in the 0.1-100 GeV energy range (95% confidence upper limit calculated for an assumed power-law model with a photon index Gamma = 2.0). The data from radio to VHE gamma-rays do not show any significant variability. Conclusions. The lack of a massive stellar counterpart disfavors the binary hypothesis, while the soft VHE spectrum would be very unusual in case of a pulsar wind nebula. In addition, the distance estimates for Galactic counterparts places them outside of the Milky Way. All available observations favor an interpretation as an extreme, high-frequency peaked BL Lac object with a redshift z > 0.14. This would be the first time a blazar is detected serendipitously from ground-based VHE observations, and the first VHE AGN detected in the Galactic Plane.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据