J/MNRAS/448/3731ivo://CDS.VizieR/J/MNRAS/448/3731doi:10.26093/cds/vizier.74483731CDSRegis M.Richter L.Colafrancesco S.Massardi M.De Blok W.J.G.,Profumo S.Orford N.2024-08-14T20:20:32Z2015-12-18T15:36:34ZCDS support team

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

cds-question@unistra.frgalaxiesradio-sourcesDwarf spheroidal (dSph) galaxies are key objects in near-field cosmology, especially in connection to the study of galaxy formation and evolution at small scales. In addition, dSphs are optimal targets to investigate the nature of dark matter. However, while we begin to have deep optical photometric observations of the stellar population in these objects, little is known so far about their diffuse emission at any observing frequency, and hence on thermal and non-thermal plasma possibly residing within dSphs. In this paper, we present deep radio observations of six local dSphs performed with the Australia Telescope Compact Array (ATCA) at 16cm wavelength. We mosaicked a region of radius of about 1{deg} around three 'classical' dSphs, Carina, Fornax, and Sculptor, and of about half of degree around three 'ultrafaint' dSphs, BootesII, Segue2, and Hercules. The rms noise level is below 0.05 mJy for all the maps. The restoring beams full width at half-maximum ranged from 4.2"x2.5" to 30.0"x2.1" in the most elongated case. A catalogue including the 1392 sources detected in the six dSph fields is reported. The main properties of the background sources are discussed, with positions and fluxes of brightest objects compared with the FIRST, NVSS, and SUMSS observations of the same fields. The observed population of radio emitters in these fields is dominated by synchrotron sources. We compute the associated source number counts at 2GHz down to fluxes of 0.25mJy, which prove to be in agreement with AGN count models.2015MNRAS.448.3731Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/448/3731CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/448/3731https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/448/3731http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/448/3731https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/448/3731https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/448/3731http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/448/3731GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/448/3731/table4 (Catalogue of radio sources in the fields of the dwarf spheroidal galaxies Carina, Fornax, Sculptor, Bootes II, Segue 2, and Hercules)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/448/3731/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/448/3731/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/448/3731/table4?GETtext/xml+votable180.050000true101.598333-51.1177780.0055555555555555565/8992 6/618-619 704-705 8738 8744 26485 26487 26493 31686-31687 31692-31694 35543 35549 35551 35714 35720 35722 35882-35883 35886 35972 39091 39094 39097 39099-39100 391021.325213914061602e-24 1.325213914061602e-24https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/448/3731?format=asciiRadiodefaultJ/MNRAS/448/3731/table4Catalogue of radio sources in the fields of the dwarf spheroidal galaxies Carina, Fornax, Sculptor, Bootes II, Segue 2, and HerculesSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainFpPeak flux density at 2GHz (un-tapered map) (2)mJyphot.flux.density;em.radio.1500-3000MHzfloatFintIntegrated flux density at 2GHz (un-tapered map)mJyphot.flux.density;em.radio.1500-3000MHzfloate_FintError on integrated flux density (3)mJystat.errorfloatbmajFWHM major axis of the source (4)arcminphys.angSizefloatbminFWHM minor axis of the source (4)arcminphys.angSizefloatPA[] Source position angle (north to east) (4)degpos.posAngfloatFgtIntegrated flux density at 2GHz in the tapered mapdegphot.flux.density;em.radio.1500-3000MHzfloatMFlagFlag for multiple component sources (5)meta.codechar