J/A+A/560/A23ivo://CDS.VizieR/J/A+A/560/A23doi:10.26093/cds/vizier.35600023CDSLiuzzo E.Giroletti M.Giovannini G.Boccardi B.Tamburri S.,Taylor G.B.Casadio C.Kadler M.Tosti G.Mignano A.2017-12-07T07:27:42Z2013-12-02T13:28:39ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiradio-continuum-emissionvery-long-baseline-interferometryThe advent of Fermi is changing our understanding on the radio and gamma-ray emission in Active Galactic Nuclei. Contrary to pre-Fermi ideas, BL Lac objects are found to be the most abundant emitters in the gamma-ray band. However, since they are relatively weak radio sources, most of their parsec-scale structure and their multi-frequency properties are poorly understood and/or have not been investigated in a systematically fashion. Our main goal is to analyze the radio and gamma-ray emission properties of a sample of 42 BL Lacs selected, for the first time in the literature, with no constraint on their radio and gamma-ray flux densities/emission. Thanks to new Very Long Baseline Array observations at 8 and 15GHz for the whole sample, we present here fundamental parameters such as radio flux densities, spectral index information, and parsec-scale structure. Moreover, we search for gamma-ray counterparts using data reported in the Second Catalog of Fermi Gamma-ray sources. Parsec-scale radio emission is observed in the majority of the sources at both frequencies. Gamma-ray counterparts are found for 14/42 sources. The comparison between our results in radio and gamma-ray bands points out the presence of a large number of faint BL Lacs showing "non classical" properties such as low source compactness, core dominance, no gamma-ray emission and steep radio spectral indexes. A deeper multiwavelength analysis will be needed.2013A&A...560A..23Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/560/A23CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/495/691 : Multifrequency catalogue of blazars Roma-BZCAT (Massaro+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/560/A23https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/560/A23http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/560/A23https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/560/A23https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/560/A23http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/560/A23GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/560/A23/list (Description of FITS maps)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/560/A23/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/560/A23/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/560/A23/list?GETtext/xml+votable180.050000true117.78987529.226527780.0055555555555555566/4255 5091 5463 5483 5703 5800 5918 6025 6088 6223 6436 6534 6641 6647 7233 7265 7518 8374 9060 9168 9316 9406 9773 10592 10656 11429-11430 11444 11936 25582 26282 26322 27722 27726 28115 28492 28517https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/560/A23?format=asciiRadiodefaultJ/A+A/560/A23/listDescription of FITS mapsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTargetBL Lac name, JHHMM+DDMM, [MGL2009] BZB JHHMM+DDMM in Simbadmeta.id;meta.maincharRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainBand[XU] VLBA band (X=8GHz, U=15GHz)instr.bandpasscharType[IM UV] UV data (UV) or FITS file of the cleaned image (IM; resolution ~0.1mas/pix)meta.note;src.morph.typecharFileNameName of the file in subdirectory mapsmeta.id;meta.filecharfitsDownload the fits filemeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharNEDSimbad column added by the CDSmeta.refchar