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

By A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, M. Baring, D. Bastieri, B. Baughman, K. Bechtol and 167 more. 2009

208 citations recorded by the source corpus.

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 (∼104 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 × 1036 erg s−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 π 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 . 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.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/8f0433ffb937822d7ce9e817548db53f246ddaf7

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Citations in the corpus

THE FIRST FERMI-LAT CATALOG OF SOURCES ABOVE 10 GeV (2013, background): “In the case of Vela, another feature that is apparent in the high-energy profile (see Figure 19) is an energy-dependent shift of the position of the third (“middle”) peak, which moves toward the second peak with increasing energy, as reported by Abdo et al. (2009h).”
The origin of galactic cosmic rays (2013, unknown): “7-3946 (Aharonian et al. 2004, 2006, 2007), later followed by the detection of the same remnant in the GeV energy range with the Fermi-LAT telescope (Abdo et al. 2011).”
THE SECOND FERMI LARGE AREA TELESCOPE CATALOG OF GAMMA-RAY PULSARS (2013, methodology): “As examples, the DM distances for PSR J2021+3651 (Abdo et al. 2009d) and PSR J0248+6021 (Theureau et al. 2011) may be more than three times greater than the true distances.”
FERMI LARGE AREA TELESCOPE FIRST SOURCE CATALOG (2010, methodology): “7−7037 which is also associated with PKS 0601−70, a blazar that was significantly variable during the time span of the 1FGL catalog (Abdo et al. 2009f).”
TOWARD UNDERSTANDING THE COSMIC-RAY ACCELERATION AT YOUNG SUPERNOVA REMNANTS INTERACTING WITH INTERSTELLAR CLOUDS: POSSIBLE APPLICATIONS TO RX J1713.7−3946 (2011, background): “The Fermi Gamma-ray Space Telescope revealed gamma-ray emissions from middle-aged SNRs interacting with molecular clouds (Abdo et al. 2009, 2010a, 2010b, 2010c).”
FERMI OBSERVATIONS OF CASSIOPEIA AND CEPHEUS: DIFFUSE GAMMA-RAY EMISSION IN THE OUTER GALAXY (2009, methodology): “A detailed discussion of the results of the fit goes beyond the scope of the present work, so it is deferred to another paper (A. A. Abdo et al. 2009, in preparation), which will address the results over several interstellar complexes in the Gould Belt and will compare them with γ-ray measurements…”
Fermi Large Area Telescope Fourth Source Catalog (2019, methodology): “More information about the LAT is provided in Atwood et al. (2009), and the in-flight calibration of the LAT is described in Abdo et al. (2009d) and Ackermann et al. (2012a, 2012c).”
Gamma-rays from molecular clouds illuminated by cosmic rays escaping from interacting supernova remnants (2010, background): “Comparison of the model results (solid line) with Fermi (red) (Abdo et al. 2009b) and HESS (blue) (Fiasson et al. 2009) observations for SNR W51C.”
Searches for Extended and Point-like Neutrino Sources with Four Years of IceCube Data (2014, background): “The catalog contains four SNRs associated with molecular clouds in the northern sky (Abdo et al. 2007, 2009a, 2009b, 2010; Ackermann et al. 2013; Fiasson et al. 2009) that were previously considered in Aartsen et al. (2013c), and six newly introduced sources from SNRCat in the southern sky.”
FERMI LARGE AREA TELESCOPE OBSERVATIONS OF THE SUPERNOVA REMNANT W28 (G6.4−0.1) (2010, background): “LAT observations of middle-aged SNRs interacting with the molecular clouds W51C (Abdo et al. 2009), W44 (Abdo et al. 2010a), and IC 443 (Abdo et al. 2010b) have revealed bright extended gamma-ray sources coincident with the SNRs.”