J/ApJ/762/93ivo://CDS.VizieR/J/ApJ/762/93doi:10.26093/cds/vizier.17620093CDSCroft S.Bower G.C.Whysong D.2014-11-04T14:14:15Z2014-10-17T11:58:38ZCDS support team

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

cds-question@unistra.frradio-continuum-emissionsurveysWe present results from a total of 459 repeated 3.1GHz radio continuum observations (of which 379 were used in a search for transient sources) of the ELAIS-N1, Coma, Lockman Hole, and NOAO Deep Wide Field Survey fields as part of the Pi GHz Sky Survey. The observations were taken approximately once per day between 2009 May and 2011 April. Each image covers 11.8 square degrees and has 100" FWHM resolution. Deep images for each of the four fields have rms noise between 180 and 310{mu}Jy, and the corresponding catalogs contain ~200 sources in each field. Typically 40-50 of these sources are detected in each single-epoch image. This represents one of the shortest cadence, largest area, multi-epoch surveys undertaken at these frequencies. We compare the catalogs generated from the combined images to those from individual epochs, and from monthly averages, as well as to legacy surveys. We undertake a search for transients, with particular emphasis on excluding false positive sources. We find no confirmed transients, defined here as sources that can be shown to have varied by at least a factor of 10. However, we find one source that brightened in a single-epoch image to at least six times the upper limit from the corresponding deep image. We also find a source associated with a z=0.6 quasar which appears to have brightened by a factor ~3 in one of our deep images, when compared to catalogs from legacy surveys. We place new upper limits on the number of transients brighter than 10mJy: fewer than 0.08 transients deg^-2^ with characteristic timescales of months to years; fewer than 0.02deg^-2^ with timescales of months; and fewer than 0.009deg^-2^ with timescales of days. We also plot upper limits as a function of flux density for transients on the same timescales.2013ApJ...762...93Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/762/93CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVIII/87 : The Allen Telescope Array 20cm Survey (ATATS). I. (Croft+ 2010)VIII/40 : GB6 catalog of radio sources (Gregory+ 1996)J/ApJ/742/49 : FIRST variable & transient radio sources (Thyagarajan+, 2011)J/ApJ/740/65 : VLA search for 5GHz radio transients (Ofek+, 2011)J/ApJ/739/76 : Pi GHz Sky Survey (PiGSS). II. (Bower+, 2011)J/ApJ/725/1792 : Pi Ghz Sky Survey (PiGSS). I. (Bower+, 2010)J/ApJ/714/1689 : DRAO ELAIS N1 catalog (Grant+, 2010)J/AJ/137/4846 : 90cm observations of the deep SWIRE field (Owen+, 2009)J/AJ/137/4436 : Coma cluster VLA survey (Miller+, 2009)J/MNRAS/397/281 : Radio imaging in Lockman Hole (Ibar+, 2009)J/MNRAS/395/269 : ELAIS-N1 field 325MHz observations (Sirothia+, 2009)J/ApJ/689/108 : MASIV survey. II. First four epochs (Lovell+, 2008)J/MNRAS/387/1037 : 610-MHz survey of Lockman Hole with GMRT (Garn+, 2008)J/ApJS/161/9 : X-ray survey of the NDWFS Bootes field (Kenter+, 2005)J/AJ/123/1784 : 1.4 GHz imaging of the Bootes field (de Vries+, 2002)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/762/93https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/762/93http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/762/93https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/762/93https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/762/93http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/762/93GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/762/93/table2 (ELAIS N1 catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/762/93/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/762/93/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/762/93/table2?GETtext/xml+votable180.050000true240.0313554.033920.005555555555555556Cone search capability for table J/ApJ/762/93/table3 (Lockman catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/762/93/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/762/93/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/762/93/table3?GETtext/xml+votable180.050000true159.5626558.504040.005555555555555556Cone search capability for table J/ApJ/762/93/table4 (Coma catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/762/93/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/762/93/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/762/93/table4?GETtext/xml+votable180.050000true192.9025528.110040.005555555555555556Cone search capability for table J/ApJ/762/93/table5 (NDWFS (NOAO Deep Wide Field Survey) updated catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/762/93/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/762/93/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/762/93/table5?GETtext/xml+votable180.050000true216.186934.305440.0055555555555555565/1517 1519 2287 2538 2594 2600 2628 6/6047 6090 6112 6114 6120 9145 9146 9147 9983 10145 10146 10147 10150 10156 10158 10380 10382 10404 10516 10517 10518 11520 11521 28125 28127 28149 281512.0143251240971855e-24 2.080585914586951e-24https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/762/93?format=asciiRadiodefaultJ/ApJ/762/93/table2ELAIS N1 catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPiGSSPiGSS identification (JHHMMSS+DDMMSS) (1)meta.id;meta.maincharRAhRight ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Decimal degree of Declination (J2000)degpos.eq.dec;meta.mainamaj[100/331] Source major axis (2)arcsecphys.angSizefloatbmin[100/163] Source minor axis (2)arcsecphys.angSize;srcfloatbPA[0/180] Source position angle (2)degpos.posAngfloatS3.04[0.9/1599] Deep image 3.04GHz flux density (3)mJyphot.flux.density;em.radio.1500-3000MHzfloate_S3.04[0.2/9] Uncertainty in S3040 (4)mJystat.errorfloato_S3.04[0/166] Number of single-epoch S3.04 images (5)meta.numberintS3.14Deep image 3.14GHz flux density (3)mJyphot.flux.density;em.radio.1500-3000MHzfloate_S3.14[0.2/23] Uncertainty in S3.14 (4)mJystat.errorfloato_S3.14[0/168] Number of single-epoch S3.14 images (5)meta.numberintNi[0/111] Number of single-epoch images at both frequencies (5)meta.numberintchi3.04[0/26]? Reduced {chi}^2^ at 3.04GHz (6)stat.fit.chi2floatnullablechi3.14[0/233]? Reduced {chi}^2^ at 3.14GHz (6)stat.fit.chi2floatnullablesig3.04[0.03/0.5]? Standard deviation at 3.04GHz (7)stat.stdevfloatnullablesig3.14[0.03/0.5]? Standard deviation at 3.14GHz (7)stat.stdevfloatnullableJ/ApJ/762/93/table3Lockman catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPiGSSPiGSS identification (JHHMMSS+DDMMSS) (1)meta.id;meta.maincharRAhRight ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Decimal degree of Declination (J2000)degpos.eq.dec;meta.mainamaj[100/331] Source major axis (2)arcsecphys.angSizefloatbmin[100/163] Source minor axis (2)arcsecphys.angSize;srcfloatbPA[0/180] Source position angle (2)degpos.posAngfloatS3.04[0.9/1599] Deep image 3.04GHz flux density (3)mJyphot.flux.density;em.radio.1500-3000MHzfloate_S3.04[0.2/9] Uncertainty in S3040 (4)mJystat.errorfloato_S3.04[0/166] Number of single-epoch S3.04 images (5)meta.numberintS3.14Deep image 3.14GHz flux density (3)mJyphot.flux.density;em.radio.1500-3000MHzfloate_S3.14[0.2/23] Uncertainty in S3.14 (4)mJystat.errorfloato_S3.14[0/168] Number of single-epoch S3.14 images (5)meta.numberintNi[0/111] Number of single-epoch images at both frequencies (5)meta.numberintchi3.04[0/26]? Reduced {chi}^2^ at 3.04GHz (6)stat.fit.chi2floatnullablechi3.14[0/233]? Reduced {chi}^2^ at 3.14GHz (6)stat.fit.chi2floatnullablesig3.04[0.03/0.5]? Standard deviation at 3.04GHz (7)stat.stdevfloatnullablesig3.14[0.03/0.5]? Standard deviation at 3.14GHz (7)stat.stdevfloatnullableJ/ApJ/762/93/table4Coma catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPiGSSPiGSS identification (JHHMMSS+DDMMSS) (1)meta.id;meta.maincharRAhRight ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Decimal degree of Declination (J2000)degpos.eq.dec;meta.mainamaj[100/331] Source major axis (2)arcsecphys.angSizefloatbmin[100/163] Source minor axis (2)arcsecphys.angSize;srcfloatbPA[0/180] Source position angle (2)degpos.posAngfloatS3.04[0.9/1599] Deep image 3.04GHz flux density (3)mJyphot.flux.density;em.radio.1500-3000MHzfloate_S3.04[0.2/9] Uncertainty in S3040 (4)mJystat.errorfloato_S3.04[0/166] Number of single-epoch S3.04 images (5)meta.numberintS3.14Deep image 3.14GHz flux density (3)mJyphot.flux.density;em.radio.1500-3000MHzfloate_S3.14[0.2/23] Uncertainty in S3.14 (4)mJystat.errorfloato_S3.14[0/168] Number of single-epoch S3.14 images (5)meta.numberintNi[0/111] Number of single-epoch images at both frequencies (5)meta.numberintchi3.04[0/26]? Reduced {chi}^2^ at 3.04GHz (6)stat.fit.chi2floatnullablechi3.14[0/233]? Reduced {chi}^2^ at 3.14GHz (6)stat.fit.chi2floatnullablesig3.04[0.03/0.5]? Standard deviation at 3.04GHz (7)stat.stdevfloatnullablesig3.14[0.03/0.5]? Standard deviation at 3.14GHz (7)stat.stdevfloatnullableJ/ApJ/762/93/table5NDWFS (NOAO Deep Wide Field Survey) updated catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPiGSSPiGSS identification (JHHMMSS+DDMMSS) (1)meta.id;meta.maincharRAhRight ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Decimal degree of Declination (J2000)degpos.eq.dec;meta.mainamaj[100/331] Source major axis (2)arcsecphys.angSizefloatbmin[100/163] Source minor axis (2)arcsecphys.angSize;srcfloatbPA[0/180] Source position angle (2)degpos.posAngfloatS3.04[0.9/1599] Deep image 3.04GHz flux density (3)mJyphot.flux.density;em.radio.1500-3000MHzfloate_S3.04[0.2/9] Uncertainty in S3040 (4)mJystat.errorfloato_S3.04[0/166] Number of single-epoch S3.04 images (5)meta.numberintS3.14Deep image 3.14GHz flux density (3)mJyphot.flux.density;em.radio.1500-3000MHzfloate_S3.14[0.2/23] Uncertainty in S3.14 (4)mJystat.errorfloato_S3.14[0/168] Number of single-epoch S3.14 images (5)meta.numberintNi[0/111] Number of single-epoch images at both frequencies (5)meta.numberintchi3.04[0/26]? Reduced {chi}^2^ at 3.04GHz (6)stat.fit.chi2floatnullablechi3.14[0/233]? Reduced {chi}^2^ at 3.14GHz (6)stat.fit.chi2floatnullablesig3.04[0.03/0.5]? Standard deviation at 3.04GHz (7)stat.stdevfloatnullablesig3.14[0.03/0.5]? Standard deviation at 3.14GHz (7)stat.stdevfloatnullablepPapDisplay the data from previous papers (Bower+, 2010, J/ApJ/725/1792 and Bower+, 2011, J/ApJ/739/76) within 51"meta.ref.urlintnullable