J/MNRAS/434/2877ivo://CDS.VizieR/J/MNRAS/434/2877doi:10.26093/cds/vizier.74342877CDSThorat K.Saripalli L.Subrahmanyan R.2024-08-06T20:16:34Z2014-10-09T15:52:51ZCDS support team

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

cds-question@unistra.frradio-sourcesredshiftedphotometryWe present a study of the environments of extended radio sources in the Australia Telescope Low-Brightness Survey (ATLBS). The radio sources were selected from the ATLBS Extended Source Sample, which is a well defined sample containing the most extended of radio sources in the ATLBS sky survey regions. The environments were analysed using 4-m Cerro-Tololo Inter-American Observatory Blanco telescope observations carried out for ATLBS fields in the Sloan Digital Sky Survey r' band. We have estimated the properties of the environments using smoothed density maps derived from galaxy catalogues constructed using these optical imaging data. The angular distribution of galaxy density relative to the axes of the radio sources has been quantified by defining anisotropy parameters that are estimated using a new method presented here. Examining the anisotropy parameters for a subsample of extended double radio sources that includes all sources with pronounced asymmetry in lobe extents, we find good evidence for environmental anisotropy being the dominant cause for lobe asymmetry in that higher galaxy density occurs almost always on the side of the shorter lobe, and this validates the usefulness of the method proposed and adopted here. The environmental anisotropy parameters have been used to examine and compare the environments of Fanaroff-Riley Class I (FRI) and Fanaroff-Riley Class II (FRII) radio sources in two redshift regimes (z<0.5 and z>0.5). Wide-angle tail sources and head-tail sources lie in the most overdense environments. The head-tail source environments (for the HT sources in our sample) display dipolar anisotropy in that higher galaxy density appears to lie in the direction of the tails. Excluding the head-tail and wide-angle tail sources, subsamples of FRI and FRII sources from the ATLBS appear to lie in similar moderately overdense environments, with no evidence for redshift evolution in the regimes studied herein.2013MNRAS.434.2877Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/434/2877CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/402/2792 : Australia Telescope Low-Brightness Survey (ATLBS)J/ApJ/762/16 : Australia Tel. Low-brightness Survey (ATLBS) (Thorat+, 2013)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/434/2877https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/434/2877http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/434/2877https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/434/2877https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/434/2877http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/434/2877GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/434/2877/table1 (The sample along with the parameters a_k_ and the standard deviations in each of the parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/434/2877/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/434/2877/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/434/2877/table1?GETtext/xml+votable180.050000true6.10833-66.603330.005555555555555556Cone search capability for table J/MNRAS/434/2877/table2 (Sources used to fit the magnitude-redshift relation)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/434/2877/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/434/2877/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/434/2877/table2?GETtext/xml+votable180.050000true5.6879167-66.88508330.0055555555555555565/8358 8361 6/33421-33423 33425-33427 33430 33443https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/434/2877?format=asciiOpticalRadiodefaultJ/MNRAS/434/2877/table1The sample along with the parameters a_k_ and the standard deviations in each of the parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintN2Number of corresponding sources in table2meta.numberintnullableATLBSSource name (JHHMM.m+DDMM)meta.id;meta.maincharNameExtended source name (JHHMMSS+DDMMSS)meta.idcharn_Name[** ] **: source from SUMSS (1)meta.notecharzRedshiftsrc.redshiftfloatn_z[*] *: spectroscopically measured redshiftmeta.notecharTypeSource type (2)src.classcharPA[-90/360] Position angledegpos.posAnginta1Best value of overdensity parameter a_1_ (3)stat.param;meta.modelledfloatba1Lower value of overdensity parameter a1 (3)stat.param;stat.minfloatBa1Upper value of overdensity parameter a1 (3)stat.param;stat.maxfloate_a1Normalized standard deviation of a1stat.errorfloata2Best value of overdensity parameter a_2_ (3)stat.param;meta.modelledfloatba2Lower value of overdensity parameter a2 (3)stat.param;stat.minfloatBa2Upper value of overdensity parameter a2 (3)stat.param;stat.maxfloate_a2Normalized standard deviation of a2stat.errorfloata3Best value of Overdensity parameter a_3_ (3)stat.param;meta.modelledfloatba3Lower value of overdensity parameter a3 (3)stat.param;stat.minfloatBa3Upper value of overdensity parameter a3 (3)stat.param;stat.maxfloate_a3Normalized standard deviation of a3stat.errorfloata4Best value of Overdensity parameter a_4_ (3)stat.param;meta.modelledfloatba4Lower value of overdensity parameter a4 (3)stat.param;stat.minfloatBa4Upper value of overdensity parameter a4 (3)stat.param;stat.maxfloate_a4Normalized standard deviation of a4stat.errorfloata5Best value of Overdensity parameter a_5_ (3)stat.param;meta.modelledfloatba5Lower value of overdensity parameter a5 (3)stat.param;stat.minfloatBa5Upper value of overdensity parameter a5 (3)stat.param;stat.maxfloate_a5Normalized standard deviation of a5stat.errorfloat_RAPosition from extended name (right ascension part)degpos.eq.ra;meta.main_DEPosition from extended name (declination part)degpos.eq.dec;meta.mainJ/MNRAS/434/2877/table2Sources used to fit the magnitude-redshift relationrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintN1Number of corresponding sources in table1meta.ref.urlintnullableRAJ2000Radio source Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Radio source Declination (J2000)pos.eq.dec;meta.mainRAOOptical ID Right ascension (J2000)meta.id;pos.eq.raDEOOptical ID Declination (J2000)meta.id;pos.eq.deczRedshiftsrc.redshiftfloatrmagr magnitudemagphot.mag;em.opt.Rfloat