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Title: FERMI LAT DISCOVERY OF EXTENDED GAMMA-RAY EMISSION IN THE DIRECTION OF SUPERNOVA REMNANT W51C

Abstract

The discovery of bright gamma-ray emission coincident with supernova remnant (SNR) W51C is reported using the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. W51C is a middle-aged remnant (approx10{sup 4} yr) with intense radio synchrotron emission in its shell and known to be interacting with a molecular cloud. The gamma-ray emission is spatially extended, broadly consistent with the radio and X-ray extent of SNR W51C. The energy spectrum in the 0.2-50 GeV band exhibits steepening toward high energies. The luminosity is greater than 1 x 10{sup 36} erg s{sup -1} given the distance constraint of D > 5.5 kpc, which makes this object one of the most luminous gamma-ray sources in our Galaxy. The observed gamma-rays can be explained reasonably by a combination of efficient acceleration of nuclear cosmic rays at supernova shocks and shock-cloud interactions. The decay of neutral pi mesons produced in hadronic collisions provides a plausible explanation for the gamma-ray emission. The product of the average gas density and the total energy content of the accelerated protons amounts to n-bar{sub H}W{sub p}approx =5 x 10{sup 51} (D/6 kpc){sup 2} erg cm{sup -3}. Electron density constraints from the radio and X-ray bands render it difficultmore » to explain the LAT signal as due to inverse Compton scattering. The Fermi LAT source coincident with SNR W51C sheds new light on the origin of Galactic cosmic rays.« less

Authors:
 [1]; ; ; ; ; ; ; ;  [2]; ; ; ;  [3];  [4];  [5];  [6];  [7];  [8];  [9];  [10]
  1. Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)
  2. W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)
  3. Istituto Nazionale di fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy)
  4. Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France)
  5. Istituto Nazionale di fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy)
  6. Rice University, Department of Physics and Astronomy, MS-108, P.O. Box 1892, Houston, TX 77251 (United States)
  7. Istituto Nazionale di fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy)
  8. Department of Physics, Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States)
  9. Istituto Nazionale di fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy)
  10. Dipartimento di fisica 'M. Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy)
Publication Date:
OSTI Identifier:
21378238
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal (Online)
Additional Journal Information:
Journal Volume: 706; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/706/1/L1; Journal ID: ISSN 1538-4357
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; COMPTON EFFECT; COSMIC GAMMA SOURCES; COSMIC RADIATION; ELECTRON DENSITY; EMISSION; ENERGY SPECTRA; GALAXIES; GAMMA RADIATION; LUMINOSITY; PIONS; PROTONS; SUPERNOVA REMNANTS; TELESCOPES; X RADIATION; BARYONS; BASIC INTERACTIONS; BOSONS; COSMIC RADIO SOURCES; COSMIC RAY SOURCES; ELASTIC SCATTERING; ELECTROMAGNETIC INTERACTIONS; ELECTROMAGNETIC RADIATION; ELEMENTARY PARTICLES; FERMIONS; HADRONS; INTERACTIONS; IONIZING RADIATIONS; MESONS; NUCLEONS; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; PSEUDOSCALAR MESONS; RADIATIONS; SCATTERING; SPECTRA

Citation Formats

Abdo, A A, Ackermann, M, Ajello, M, Bechtol, K, Berenji, B, Blandford, R D, Bloom, E D, Borgland, A W, Bouvier, A, Baldini, L, Bellazzini, R, Bregeon, J, Brez, A, Ballet, J, Barbiellini, G, Baring, M G, Bastieri, D, Baughman, B M, Bonamente, E, and Brigida, M. FERMI LAT DISCOVERY OF EXTENDED GAMMA-RAY EMISSION IN THE DIRECTION OF SUPERNOVA REMNANT W51C. United States: N. p., 2009. Web. doi:10.1088/0004-637X/706/1/L1.
Abdo, A A, Ackermann, M, Ajello, M, Bechtol, K, Berenji, B, Blandford, R D, Bloom, E D, Borgland, A W, Bouvier, A, Baldini, L, Bellazzini, R, Bregeon, J, Brez, A, Ballet, J, Barbiellini, G, Baring, M G, Bastieri, D, Baughman, B M, Bonamente, E, & Brigida, M. FERMI LAT DISCOVERY OF EXTENDED GAMMA-RAY EMISSION IN THE DIRECTION OF SUPERNOVA REMNANT W51C. United States. doi:10.1088/0004-637X/706/1/L1.
Abdo, A A, Ackermann, M, Ajello, M, Bechtol, K, Berenji, B, Blandford, R D, Bloom, E D, Borgland, A W, Bouvier, A, Baldini, L, Bellazzini, R, Bregeon, J, Brez, A, Ballet, J, Barbiellini, G, Baring, M G, Bastieri, D, Baughman, B M, Bonamente, E, and Brigida, M. Fri . "FERMI LAT DISCOVERY OF EXTENDED GAMMA-RAY EMISSION IN THE DIRECTION OF SUPERNOVA REMNANT W51C". United States. doi:10.1088/0004-637X/706/1/L1.
@article{osti_21378238,
title = {FERMI LAT DISCOVERY OF EXTENDED GAMMA-RAY EMISSION IN THE DIRECTION OF SUPERNOVA REMNANT W51C},
author = {Abdo, A A and Ackermann, M and Ajello, M and Bechtol, K and Berenji, B and Blandford, R D and Bloom, E D and Borgland, A W and Bouvier, A and Baldini, L and Bellazzini, R and Bregeon, J and Brez, A and Ballet, J and Barbiellini, G and Baring, M G and Bastieri, D and Baughman, B M and Bonamente, E and Brigida, M},
abstractNote = {The discovery of bright gamma-ray emission coincident with supernova remnant (SNR) W51C is reported using the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. W51C is a middle-aged remnant (approx10{sup 4} yr) with intense radio synchrotron emission in its shell and known to be interacting with a molecular cloud. The gamma-ray emission is spatially extended, broadly consistent with the radio and X-ray extent of SNR W51C. The energy spectrum in the 0.2-50 GeV band exhibits steepening toward high energies. The luminosity is greater than 1 x 10{sup 36} erg s{sup -1} given the distance constraint of D > 5.5 kpc, which makes this object one of the most luminous gamma-ray sources in our Galaxy. The observed gamma-rays can be explained reasonably by a combination of efficient acceleration of nuclear cosmic rays at supernova shocks and shock-cloud interactions. The decay of neutral pi mesons produced in hadronic collisions provides a plausible explanation for the gamma-ray emission. The product of the average gas density and the total energy content of the accelerated protons amounts to n-bar{sub H}W{sub p}approx =5 x 10{sup 51} (D/6 kpc){sup 2} erg cm{sup -3}. Electron density constraints from the radio and X-ray bands render it difficult to explain the LAT signal as due to inverse Compton scattering. The Fermi LAT source coincident with SNR W51C sheds new light on the origin of Galactic cosmic rays.},
doi = {10.1088/0004-637X/706/1/L1},
journal = {Astrophysical Journal (Online)},
issn = {1538-4357},
number = 1,
volume = 706,
place = {United States},
year = {2009},
month = {11}
}

Works referencing / citing this record:

Observational Signatures of Particle Acceleration in Supernova Remnants
journal, August 2012


The supernova remnant W49B as seen with H.E.S.S. and Fermi-LAT
journal, April 2018


On the nature of the TeV emission from the supernova remnant SN 1006: On the nature of the TeV emission from SNR
journal, September 2012


Escape of cosmic-ray electrons from supernova remnants: Escape of CR electrons from SNRs
journal, October 2012


Second AGILE catalogue of gamma-ray sources
journal, June 2019


THE DIFFUSE GAMMA-RAY BACKGROUND FROM TYPE Ia SUPERNOVAE
journal, February 2012


Fermi – LARGE AREA TELESCOPE: ACCOMPLISHMENTS AND CHALLENGES
journal, January 2013


Observational Signatures of Particle Acceleration in Supernova Remnants
journal, August 2012


The supernova remnant W49B as seen with H.E.S.S. and Fermi-LAT
journal, April 2018


Second AGILE catalogue of gamma-ray sources
journal, June 2019


THE DIFFUSE GAMMA-RAY BACKGROUND FROM TYPE Ia SUPERNOVAE
journal, February 2012


On the nature of the TeV emission from the supernova remnant SN 1006: On the nature of the TeV emission from SNR
journal, September 2012


Escape of cosmic-ray electrons from supernova remnants: Escape of CR electrons from SNRs
journal, October 2012


Fermi – LARGE AREA TELESCOPE: ACCOMPLISHMENTS AND CHALLENGES
journal, January 2013