J/A+A/679/A22ivo://CDS.VizieR/J/A+A/679/A22doi:10.26093/cds/vizier/bc-n7/lccCDSSupan L.Castelletti G.Lemiere A.2026-07-01T14:01:16Z2023-10-31T08:08:03ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frsupernova-remnantsinterstellar-mediumradio-continuum-emissiongamma-ray-astronomyThis paper presents a comprehensive analysis of the Galactic supernova remnant (SNR) Kes 17 (G304.6+0.1). The focus is on its radio synchrotron emission, its surroundings, and the factors contributing to the observed gamma rays. The fitting to the first obtained integrated radio continuum spectrum spanning from 88 to 8800MHz yields an index alpha=-0.488+/-0.023 (S_nu_ propto nu^alpha^), which is indicative of a linear particle acceleration process at the shock front of the remnant. Accounting for the SNR radio shell size, the distribution of atomic hydrogen (n_H_ ~10cm^-3^), and assuming that the SNR is in the Sedov-Taylor stage of its evolution, we estimate that the remnant age is roughly 11 kyr. This result falls at the lower end of the wide range (~2-64kyr) derived from previous analyses of the diffuse X-ray emission interior to the remnant. Furthermore, we used ^12^CO and ^13^CO (J=1-0) emission line data as a proxy for molecular hydrogen and provide the first evidence that the eastern shell of Kes 17 is engulfing a molecular enhancement in the surrounding gas, with an average mass 4.2x10^4^M_{sun}_ and density n~300cm^-3^ . Towards the western boundary of Kes 17, no signatures of carbon monoxide emissions are detected above 3 sigma, despite previously reported infrared observations that revealed shocked molecular gas at this location. This suggests the existence of a CO-dark interacting molecular gas, a phenomenon also recorded in other Galactic SNRs (e.g. CTB 37A and RX J1713.7-3946) that reveals itself both in the infrared and gamma-ray domains. Additionally, by analysing ~14.5yr of continuously collected data from the Large Area Telescope on board the satellite Fermi, we determined that the best-fit power-law photon index for the 0.3-300GeV gamma-ray emission from the Kes 17 region is Gamma=2.39+/-0.04^+0.063^_-0.114_(+/-stat+/-syst), in agreement with prior studies. The energy flux is (2.98+/-0.14)x10^-11^erg/cm^2^/s, implying a luminosity (2.22+/-0.45)x10^35^erg/s at ~8kpc. Finally, we successfully modelled the multiwavelength spectral energy distribution by incorporating the radio-synchrotron spectrum and the new measurements of GeV gamma-rays. Our analysis indicates that the observed gamma-ray flux most likely originates from the interaction of Kes 17 with a western dark CO zone with a proton density n_p_~400cm^-3^.2023A&A...679A..22Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/679/A22CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/679/A22https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/679/A22http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/679/A22https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/679/A22https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/679/A22http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/679/A22GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/679/A22/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/679/A22/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/679/A22/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/679/A22/list?GETtext/xml+votable180.050000true196.3961-62.69380.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/679/A226/41657 41659-41660https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/679/A22?format=asciiGamma-rayRadiodefaultJ/A+A/679/A22/table1Flux densities with errorsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFreqFrequencyMHzem.freqintSFlux density (1)Jyphot.fluxfloate_SFlux density error (1)Jystat.errorfloatJ/A+A/679/A22/listList of fits imagesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitsAssocDataAssociated Data web pagemeta.ref.urlchar