H.E.S.S. detection of TeV emission from the interaction region between the supernova remnant G349.7+0.2 and a molecular cloud

H.E.S.S. Collaboration

doi:10.1051/0004-6361/201425070

H.E.S.S. detection of TeV emission from the interaction region between the supernova remnant G349.7+0.2 and a molecular cloud

H.E.S.S. Collaboration

Universität Hamburg
Max-Planck-Institut für Kernphysik
Dublin Institute for Advanced Studies
National Academy of Sciences of Armenia
Yerevan Physics Institute
Humboldt-Universität zu Berlin
University of Namibia
Durham University
University of Amsterdam
Jagiellonian University
Center for Astrophysics | Harvard & Smithsonian
Linnaeus University, Växjö
Ruhr-University Bochum
University of Amsterdam
University of Innsbruck
Ip Paris
University of California at Santa Cruz
North-West University
Centre national de la recherche scientifique
Sorbonne Université
University of Tübingen
Laboratoire Univers et Particules de Montpellier
Universite Paris-Saclay
University of Warsaw
Institute for Nuclear Physics
University of the Witwatersrand, Johannesburg
Landessternwarte Heidelberg
Stockholm University
University of Adelaide
Astroparticule and Cosmol APC
LTHE (UMR 5564 CNRS/IRD/Université de Grenoble)
University of Leicester
Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences
University of Potsdam
Université Savoie Mont Blanc
c/o DESY
Univ. Bordeaux
Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen
Nicolaus Copernicus University
University of the Free State

Research output: Contribution to journal › Article › peer-review

Abstract

G349.7+0.2 is a young Galactic supernova remnant (SNR) located at the distance of 11.5 kpc and observed across the entire electromagnetic spectrum from radio to high energy (HE; 0.1 GeV < E < 100 GeV) γ-rays. Radio and infrared observations indicate that the remnant is interacting with a molecular cloud. In this paper, the detection of very high energy (VHE, E > 100 GeV) γ-ray emission coincident with this SNR with the High Energy Stereoscopic System (H.E.S.S.) is reported. This makes it one of the farthest Galactic SNR ever detected in this domain. An integral flux F (E > 400 GeV) = (6.5 ± 1.1_stat ± 1.3_syst) × 10^-13 ph cm^-2 s^-1 corresponding to ∼0.7% of that of the Crab Nebula and to a luminosity of ∼10³⁴ erg s^-1 above the same energy threshold, and a steep photon index Γ_VHE = 2.8 ± 0.27stat ± 0.20_syst are measured. The analysis of more than 5 yr of Fermi-LAT data towards this source shows a power-law like spectrum with a best-fit photon index Γ_HE = 2.2 ± 0.04_stat-0.31 ^+0.13 _sys. The combined γ-ray spectrum of G349.7+0.2 can be described by either a broken power-law (BPL) or a power-law with exponential (or sub-exponential) cutoff(PLC). In the former case, the photon break energy is found at E_br,γ = 55_-30 ⁺⁷⁰GeV, slightly higher than what is usually observed in the HE/VHE γ-ray emitting middle-aged SNRs known to be interacting with molecular clouds. In the latter case, the exponential (respectively sub-exponential) cutoff energy is measured at E_cut,γ = 1.4_-0.55 ^+1.6 (respectively 0.35_-0.21 ^+0.75) TeV. A pion-decay process resulting from the interaction of the accelerated protons and nuclei with the dense surrounding medium is clearly the preferred scenario to explain the γ-ray emission. The BPL with a spectral steepening of 0.5-1 and the PLC provide equally good fits to the data. The product of the average gas density and the total energy content of accelerated protons and nuclei amounts to n_H W_p ∼ 5 × 10⁵¹ erg cm^-3.

Original language	English
Article number	A100
Journal	Astronomy and Astrophysics
Volume	574
DOIs	https://doi.org/10.1051/0004-6361/201425070
Publication status	Published - 1 Feb 2015

Keywords

Gamma rays: General
ISM: clouds
ISM: supernova remnants

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10.1051/0004-6361/201425070

Cite this

@article{59754e7e3ef94456a76fb38bcd54abb8,

title = "H.E.S.S. detection of TeV emission from the interaction region between the supernova remnant G349.7+0.2 and a molecular cloud",

abstract = "G349.7+0.2 is a young Galactic supernova remnant (SNR) located at the distance of 11.5 kpc and observed across the entire electromagnetic spectrum from radio to high energy (HE; 0.1 GeV < E < 100 GeV) γ-rays. Radio and infrared observations indicate that the remnant is interacting with a molecular cloud. In this paper, the detection of very high energy (VHE, E > 100 GeV) γ-ray emission coincident with this SNR with the High Energy Stereoscopic System (H.E.S.S.) is reported. This makes it one of the farthest Galactic SNR ever detected in this domain. An integral flux F (E > 400 GeV) = (6.5 ± 1.1stat ± 1.3syst) × 10-13 ph cm-2 s-1 corresponding to ∼0.7\% of that of the Crab Nebula and to a luminosity of ∼1034 erg s-1 above the same energy threshold, and a steep photon index ΓVHE = 2.8 ± 0.27stat ± 0.20syst are measured. The analysis of more than 5 yr of Fermi-LAT data towards this source shows a power-law like spectrum with a best-fit photon index ΓHE = 2.2 ± 0.04stat-0.31 +0.13 sys. The combined γ-ray spectrum of G349.7+0.2 can be described by either a broken power-law (BPL) or a power-law with exponential (or sub-exponential) cutoff(PLC). In the former case, the photon break energy is found at Ebr,γ = 55-30 +70GeV, slightly higher than what is usually observed in the HE/VHE γ-ray emitting middle-aged SNRs known to be interacting with molecular clouds. In the latter case, the exponential (respectively sub-exponential) cutoff energy is measured at Ecut,γ = 1.4-0.55 +1.6 (respectively 0.35-0.21 +0.75) TeV. A pion-decay process resulting from the interaction of the accelerated protons and nuclei with the dense surrounding medium is clearly the preferred scenario to explain the γ-ray emission. The BPL with a spectral steepening of 0.5-1 and the PLC provide equally good fits to the data. The product of the average gas density and the total energy content of accelerated protons and nuclei amounts to nH Wp ∼ 5 × 1051 erg cm-3.",

keywords = "Gamma rays: General, ISM: clouds, ISM: supernova remnants",

author = "\{H.E.S.S. Collaboration\} and A. Abramowski and F. Aharonian and \{Ait Benkhali\}, F. and Akhperjanian, \{A. G.\} and Ang{\"u}ner, \{E. O.\} and M. Backes and S. Balenderan and A. Balzer and A. Barnacka and Y. Becherini and \{Becker Tjus\}, J. and D. Berge and S. Bernhard and K. Bernl{\"o}hr and E. Birsin and J. Biteau and M. B{\"o}ttcher and C. Boisson and J. Bolmont and P. Bordas and J. Bregeon and F. Brun and P. Brun and M. Bryan and T. Bulik and S. Carrigan and S. Casanova and Chadwick, \{P. M.\} and N. Chakraborty and R. Chalme-Calvet and Chaves, \{R. C.G.\} and M. Chr{\'e}tien and S. Colafrancesco and G. Cologna and J. Conrad and C. Couturier and Y. Cui and Davids, \{I. D.\} and B. Degrange and C. Deil and P. DeWilt and A. Djannati-Ata{\"i} and W. Domainko and A. Donath and Drury, \{L. O.C.\} and G. Dubus and K. Dutson and J. Dyks and M. Dyrda and S. Fegan",

note = "Publisher Copyright: {\textcopyright} ESO 2015.",

year = "2015",

month = feb,

day = "1",

doi = "10.1051/0004-6361/201425070",

language = "English",

volume = "574",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

}

TY - JOUR

T1 - H.E.S.S. detection of TeV emission from the interaction region between the supernova remnant G349.7+0.2 and a molecular cloud

AU - H.E.S.S. Collaboration

AU - Abramowski, A.

AU - Aharonian, F.

AU - Ait Benkhali, F.

AU - Akhperjanian, A. G.

AU - Angüner, E. O.

AU - Backes, M.

AU - Balenderan, S.

AU - Balzer, A.

AU - Barnacka, A.

AU - Becherini, Y.

AU - Becker Tjus, J.

AU - Berge, D.

AU - Bernhard, S.

AU - Bernlöhr, K.

AU - Birsin, E.

AU - Biteau, J.

AU - Böttcher, M.

AU - Boisson, C.

AU - Bolmont, J.

AU - Bordas, P.

AU - Bregeon, J.

AU - Brun, F.

AU - Brun, P.

AU - Bryan, M.

AU - Bulik, T.

AU - Carrigan, S.

AU - Casanova, S.

AU - Chadwick, P. M.

AU - Chakraborty, N.

AU - Chalme-Calvet, R.

AU - Chaves, R. C.G.

AU - Chrétien, M.

AU - Colafrancesco, S.

AU - Cologna, G.

AU - Conrad, J.

AU - Couturier, C.

AU - Cui, Y.

AU - Davids, I. D.

AU - Degrange, B.

AU - Deil, C.

AU - DeWilt, P.

AU - Djannati-Ataï, A.

AU - Domainko, W.

AU - Donath, A.

AU - Drury, L. O.C.

AU - Dubus, G.

AU - Dutson, K.

AU - Dyks, J.

AU - Dyrda, M.

AU - Fegan, S.

PY - 2015/2/1

Y1 - 2015/2/1

N2 - G349.7+0.2 is a young Galactic supernova remnant (SNR) located at the distance of 11.5 kpc and observed across the entire electromagnetic spectrum from radio to high energy (HE; 0.1 GeV < E < 100 GeV) γ-rays. Radio and infrared observations indicate that the remnant is interacting with a molecular cloud. In this paper, the detection of very high energy (VHE, E > 100 GeV) γ-ray emission coincident with this SNR with the High Energy Stereoscopic System (H.E.S.S.) is reported. This makes it one of the farthest Galactic SNR ever detected in this domain. An integral flux F (E > 400 GeV) = (6.5 ± 1.1stat ± 1.3syst) × 10-13 ph cm-2 s-1 corresponding to ∼0.7% of that of the Crab Nebula and to a luminosity of ∼1034 erg s-1 above the same energy threshold, and a steep photon index ΓVHE = 2.8 ± 0.27stat ± 0.20syst are measured. The analysis of more than 5 yr of Fermi-LAT data towards this source shows a power-law like spectrum with a best-fit photon index ΓHE = 2.2 ± 0.04stat-0.31 +0.13 sys. The combined γ-ray spectrum of G349.7+0.2 can be described by either a broken power-law (BPL) or a power-law with exponential (or sub-exponential) cutoff(PLC). In the former case, the photon break energy is found at Ebr,γ = 55-30 +70GeV, slightly higher than what is usually observed in the HE/VHE γ-ray emitting middle-aged SNRs known to be interacting with molecular clouds. In the latter case, the exponential (respectively sub-exponential) cutoff energy is measured at Ecut,γ = 1.4-0.55 +1.6 (respectively 0.35-0.21 +0.75) TeV. A pion-decay process resulting from the interaction of the accelerated protons and nuclei with the dense surrounding medium is clearly the preferred scenario to explain the γ-ray emission. The BPL with a spectral steepening of 0.5-1 and the PLC provide equally good fits to the data. The product of the average gas density and the total energy content of accelerated protons and nuclei amounts to nH Wp ∼ 5 × 1051 erg cm-3.

AB - G349.7+0.2 is a young Galactic supernova remnant (SNR) located at the distance of 11.5 kpc and observed across the entire electromagnetic spectrum from radio to high energy (HE; 0.1 GeV < E < 100 GeV) γ-rays. Radio and infrared observations indicate that the remnant is interacting with a molecular cloud. In this paper, the detection of very high energy (VHE, E > 100 GeV) γ-ray emission coincident with this SNR with the High Energy Stereoscopic System (H.E.S.S.) is reported. This makes it one of the farthest Galactic SNR ever detected in this domain. An integral flux F (E > 400 GeV) = (6.5 ± 1.1stat ± 1.3syst) × 10-13 ph cm-2 s-1 corresponding to ∼0.7% of that of the Crab Nebula and to a luminosity of ∼1034 erg s-1 above the same energy threshold, and a steep photon index ΓVHE = 2.8 ± 0.27stat ± 0.20syst are measured. The analysis of more than 5 yr of Fermi-LAT data towards this source shows a power-law like spectrum with a best-fit photon index ΓHE = 2.2 ± 0.04stat-0.31 +0.13 sys. The combined γ-ray spectrum of G349.7+0.2 can be described by either a broken power-law (BPL) or a power-law with exponential (or sub-exponential) cutoff(PLC). In the former case, the photon break energy is found at Ebr,γ = 55-30 +70GeV, slightly higher than what is usually observed in the HE/VHE γ-ray emitting middle-aged SNRs known to be interacting with molecular clouds. In the latter case, the exponential (respectively sub-exponential) cutoff energy is measured at Ecut,γ = 1.4-0.55 +1.6 (respectively 0.35-0.21 +0.75) TeV. A pion-decay process resulting from the interaction of the accelerated protons and nuclei with the dense surrounding medium is clearly the preferred scenario to explain the γ-ray emission. The BPL with a spectral steepening of 0.5-1 and the PLC provide equally good fits to the data. The product of the average gas density and the total energy content of accelerated protons and nuclei amounts to nH Wp ∼ 5 × 1051 erg cm-3.

KW - Gamma rays: General

KW - ISM: clouds

KW - ISM: supernova remnants

UR - https://www.scopus.com/pages/publications/84961299965

U2 - 10.1051/0004-6361/201425070

DO - 10.1051/0004-6361/201425070

M3 - Article

AN - SCOPUS:84961299965

SN - 0004-6361

VL - 574

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

M1 - A100

ER -

H.E.S.S. detection of TeV emission from the interaction region between the supernova remnant G349.7+0.2 and a molecular cloud

Abstract

Keywords

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