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Title: HESS J1640–465 AND HESS J1641–463: TWO INTRIGUING TeV SOURCES IN LIGHT OF NEW FERMI -LAT OBSERVATIONS

We report on γ-ray analysis of the region containing the bright TeV source HESS J1640-465 and the closeby TeV source HESS J1641-463 using 64 months of observationswith the Fermi Large Area Telescope (LAT). Previously only one GeV source was reported in this region and was associated with HESS J1640-465. With an increased dataset and the improved sensitivity afforded by the reprocessed data (P7REP) of the LAT, we now report the detection, morphological study and spectral analysis of two distinct sources above 100 MeV. The softest emission in this region comes from the TeV source HESS J1641-463 which is well fitted with a power law of index Γ = 2.47 ± 0.05 ± 0.06 and presents no significant γ-ray signal above 10 GeV, which contrasts with its hard spectrum at TeV energies. The Fermi-LAT spectrum of the second TeV source, HESS J1640-465 is well described by a power-law shape of index Γ = 1.99 ± 0.04 ± 0.07 that links up naturally with the spectral data points obtained by the High Energy Stereoscopic System (H.E.S.S.). These new results provide new constraints concerning the identification of these two puzzling γ-ray sources.
Authors:
ORCiD logo [1] ;  [1] ;  [2] ; ORCiD logo [2] ;  [1] ;  [1]
  1. Univ. Bordeaux (France)
  2. Univ. Paris Diderot (France)
Publication Date:
Grant/Contract Number:
AC02-76SF00515
Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal. Letters
Additional Journal Information:
Journal Volume: 794; Journal Issue: 1; Journal ID: ISSN 2041-8213
Publisher:
Institute of Physics (IOP)
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS
OSTI Identifier:
1356449

Lemoine-Goumard, M., Grondin, M. -H., Acero, F., Ballet, J., Laffon, H., and Reposeur, T.. HESS J1640–465 AND HESS J1641–463: TWO INTRIGUING TeV SOURCES IN LIGHT OF NEW FERMI -LAT OBSERVATIONS. United States: N. p., Web. doi:10.1088/2041-8205/794/1/L16.
Lemoine-Goumard, M., Grondin, M. -H., Acero, F., Ballet, J., Laffon, H., & Reposeur, T.. HESS J1640–465 AND HESS J1641–463: TWO INTRIGUING TeV SOURCES IN LIGHT OF NEW FERMI -LAT OBSERVATIONS. United States. doi:10.1088/2041-8205/794/1/L16.
Lemoine-Goumard, M., Grondin, M. -H., Acero, F., Ballet, J., Laffon, H., and Reposeur, T.. 2014. "HESS J1640–465 AND HESS J1641–463: TWO INTRIGUING TeV SOURCES IN LIGHT OF NEW FERMI -LAT OBSERVATIONS". United States. doi:10.1088/2041-8205/794/1/L16. https://www.osti.gov/servlets/purl/1356449.
@article{osti_1356449,
title = {HESS J1640–465 AND HESS J1641–463: TWO INTRIGUING TeV SOURCES IN LIGHT OF NEW FERMI -LAT OBSERVATIONS},
author = {Lemoine-Goumard, M. and Grondin, M. -H. and Acero, F. and Ballet, J. and Laffon, H. and Reposeur, T.},
abstractNote = {We report on γ-ray analysis of the region containing the bright TeV source HESS J1640-465 and the closeby TeV source HESS J1641-463 using 64 months of observationswith the Fermi Large Area Telescope (LAT). Previously only one GeV source was reported in this region and was associated with HESS J1640-465. With an increased dataset and the improved sensitivity afforded by the reprocessed data (P7REP) of the LAT, we now report the detection, morphological study and spectral analysis of two distinct sources above 100 MeV. The softest emission in this region comes from the TeV source HESS J1641-463 which is well fitted with a power law of index Γ = 2.47 ± 0.05 ± 0.06 and presents no significant γ-ray signal above 10 GeV, which contrasts with its hard spectrum at TeV energies. The Fermi-LAT spectrum of the second TeV source, HESS J1640-465 is well described by a power-law shape of index Γ = 1.99 ± 0.04 ± 0.07 that links up naturally with the spectral data points obtained by the High Energy Stereoscopic System (H.E.S.S.). These new results provide new constraints concerning the identification of these two puzzling γ-ray sources.},
doi = {10.1088/2041-8205/794/1/L16},
journal = {The Astrophysical Journal. Letters},
number = 1,
volume = 794,
place = {United States},
year = {2014},
month = {9}
}