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Title: HESS J1427−608: AN UNUSUAL HARD, UNBROKEN γ -RAY SPECTRUM IN A VERY WIDE ENERGY RANGE

Abstract

We report the detection of a GeV γ -ray source that spatially overlaps and is thus very likely associated with the unidentified very high energy (VHE) γ -ray source HESS J1427−608 with the Pass 8 data recorded by the Fermi Large Area Telescope . The photon spectrum of this source is best described by a power law with an index of 1.85 ± 0.17 in the energy range of 3–500 GeV, and the measured flux connects smoothly with that of HESS J1427−608 at a few hundred gigaelectronvolts. This source shows no significant extension and time variation. The broadband GeV to TeV emission over four decades of energies can be well fitted by a single power-law function with an index of 2.0, without obvious indication of spectral cutoff toward high energies. Such a result implies that HESS J1427−608 may be a PeV particle accelerator. We discuss the possible nature of HESS J1427−608 according to the multiwavelength spectral fittings. Given the relatively large errors, either a leptonic or a hadronic model can explain the multiwavelength data from radio to VHE γ -rays. The inferred magnetic field strength is a few micro-Gauss, which is smaller than the typical values of supernova remnants (SNRs)more » and is consistent with some pulsar wind nebulae (PWNe). On the other hand, the flat γ -ray spectrum is slightly different from typical PWNe but is similar to that of some known SNRs.« less

Authors:
;  [1]; ; ; ; ; ;  [2]
  1. Department of Physics and Institute of Theoretical Physics, Nanjing Normal University, Nanjing 210046 (China)
  2. Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)
Publication Date:
OSTI Identifier:
22664029
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 835; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATORS; COSMIC GAMMA SOURCES; DETECTION; EMISSION; GAMMA RADIATION; GAMMA SOURCES; GAMMA SPECTRA; GEV RANGE; MAGNETIC FIELDS; NEBULAE; PEV RANGE; PHOTONS; PULSARS; SUPERNOVA REMNANTS; TELESCOPES; TEV RANGE; VARIATIONS

Citation Formats

Guo, Xiao-Lei, Gao, Wei-Hong, Xin, Yu-Liang, Liao, Neng-Hui, Yuan, Qiang, He, Hao-Ning, Fan, Yi-Zhong, and Liu, Si-Ming, E-mail: yuanq@pmo.ac.cn, E-mail: gaoweihong@njnu.edu.cn, E-mail: liusm@pmo.ac.cn. HESS J1427−608: AN UNUSUAL HARD, UNBROKEN γ -RAY SPECTRUM IN A VERY WIDE ENERGY RANGE. United States: N. p., 2017. Web. doi:10.3847/1538-4357/835/1/42.
Guo, Xiao-Lei, Gao, Wei-Hong, Xin, Yu-Liang, Liao, Neng-Hui, Yuan, Qiang, He, Hao-Ning, Fan, Yi-Zhong, & Liu, Si-Ming, E-mail: yuanq@pmo.ac.cn, E-mail: gaoweihong@njnu.edu.cn, E-mail: liusm@pmo.ac.cn. HESS J1427−608: AN UNUSUAL HARD, UNBROKEN γ -RAY SPECTRUM IN A VERY WIDE ENERGY RANGE. United States. doi:10.3847/1538-4357/835/1/42.
Guo, Xiao-Lei, Gao, Wei-Hong, Xin, Yu-Liang, Liao, Neng-Hui, Yuan, Qiang, He, Hao-Ning, Fan, Yi-Zhong, and Liu, Si-Ming, E-mail: yuanq@pmo.ac.cn, E-mail: gaoweihong@njnu.edu.cn, E-mail: liusm@pmo.ac.cn. Fri . "HESS J1427−608: AN UNUSUAL HARD, UNBROKEN γ -RAY SPECTRUM IN A VERY WIDE ENERGY RANGE". United States. doi:10.3847/1538-4357/835/1/42.
@article{osti_22664029,
title = {HESS J1427−608: AN UNUSUAL HARD, UNBROKEN γ -RAY SPECTRUM IN A VERY WIDE ENERGY RANGE},
author = {Guo, Xiao-Lei and Gao, Wei-Hong and Xin, Yu-Liang and Liao, Neng-Hui and Yuan, Qiang and He, Hao-Ning and Fan, Yi-Zhong and Liu, Si-Ming, E-mail: yuanq@pmo.ac.cn, E-mail: gaoweihong@njnu.edu.cn, E-mail: liusm@pmo.ac.cn},
abstractNote = {We report the detection of a GeV γ -ray source that spatially overlaps and is thus very likely associated with the unidentified very high energy (VHE) γ -ray source HESS J1427−608 with the Pass 8 data recorded by the Fermi Large Area Telescope . The photon spectrum of this source is best described by a power law with an index of 1.85 ± 0.17 in the energy range of 3–500 GeV, and the measured flux connects smoothly with that of HESS J1427−608 at a few hundred gigaelectronvolts. This source shows no significant extension and time variation. The broadband GeV to TeV emission over four decades of energies can be well fitted by a single power-law function with an index of 2.0, without obvious indication of spectral cutoff toward high energies. Such a result implies that HESS J1427−608 may be a PeV particle accelerator. We discuss the possible nature of HESS J1427−608 according to the multiwavelength spectral fittings. Given the relatively large errors, either a leptonic or a hadronic model can explain the multiwavelength data from radio to VHE γ -rays. The inferred magnetic field strength is a few micro-Gauss, which is smaller than the typical values of supernova remnants (SNRs) and is consistent with some pulsar wind nebulae (PWNe). On the other hand, the flat γ -ray spectrum is slightly different from typical PWNe but is similar to that of some known SNRs.},
doi = {10.3847/1538-4357/835/1/42},
journal = {Astrophysical Journal},
number = 1,
volume = 835,
place = {United States},
year = {Fri Jan 20 00:00:00 EST 2017},
month = {Fri Jan 20 00:00:00 EST 2017}
}