J/A+A/660/A48ivo://CDS.VizieR/J/A+A/660/A48doi:10.26093/cds/vizier.36600048CDSLoi F.Serra P.Murgia M.Govoni F.Anderson C.Heald G.Kleiner D.,Lenc E.Vacca V.Maccagni M.Dettmar R.J.2022-09-08T09:25:46Z2022-04-08T12:09:02ZCDS support team

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

cds-question@unistra.frgalaxiesh-i-line-emissionpolarimetryRecent MeerKAT neutral hydrogen (HI) observations of Fornax A reveal tidal material intersecting in projection the western lobe of this radio galaxy. We found a spatial coincidence between the northern HI tail and a depolarized structure observed for the first time with the Australian Square Kilometre Array Pathfinder (ASKAP) at 1.2GHz. We analyzed the properties of the rotation measure (RM) image obtained with ASKAP data at the location of the HI tail and in its neighborhood. We modeled the observed RM structure function to investigate the magnetic field power spectrum at the location of the HI tail and in a nearby control region. We found that the observed RM, in the control region and in a region enclosing the HI tail, cannot be due to the intracluster Faraday screen caused by the Fornax cluster. An intragroup magnetized medium with a central magnetic field strength of 18.5uG can explain the control region RM, but it is clear that there is an excess in correspondence with the HI tail region. We evaluated several scenarios in which the HI tail is either in the lobe foreground or embedded in the lobe. We determined a magnetic field strength on the order of ~9.5-11uG in the HI tail, a value consistent with constraints derived from narrowband H{alpha} imaging of the ionized gas. The spatial coincidence between HI tail and depolarization analyzed in this paper could be the first observed evidence of a magnetic field that either has passed through a radio galaxy lobe or has survived the lobe expansion.2022A&A...660A..48Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/660/A48CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/645/256 : XMM observations of Fornax A (NGC 1316) (Isobe+, 2006)J/MNRAS/461/4260 : NGC1316 (Fornax A) g'r'i' photometry (Sesto+, 2016)J/A+A/656/A45 : Feeding and feedback in Fornax A (Maccagni+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/660/A48https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/660/A48http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/660/A48https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/660/A48https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/660/A48http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/660/A48GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/660/A48/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/660/A48/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/660/A48/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/660/A48/list?GETtext/xml+votable180.050000true50.6734-37.208680.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/660/A486/34493https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/660/A48?format=asciiRadiodefaultJ/A+A/660/A48/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.mainscale? Scale of the imagearcsec/pixinstr.scalefloatnullableNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintObs.dateObservation datestime.epoch;obsnullablesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.ref.urlchar