Infrared Imaging of z = 2.43 Radio Galaxy B3 0731+438 with the Subaru Telescope — Detection of Hα a Ionization Cones of a Powerful Radio Galaxy

[摘要] Wereportoninfraredimagingobservationsofthez=2.429radiogalaxyB30731+438withtheSubarutelescope.TheimagesweretakenwiththeK′-bandfilterandthe2.25μmnarrow-bandfiltertoexaminethestructureandpropertiesoftheHα+[NII]λλ6548,6583emission-linecomponents.TheHα+[NII]emission-lineimageshowsbiconicallobeswithanextentof40kpc,whicharealignedwiththeradioaxis.Therest-frameequivalentwidthsoftheemissionlinesattheseconesareaslargeas1100Ã…,andcanbewellexplainedbyagas-cloudmodelphotoionizedbypower-lawcontinuumradiation.Theisotropicionizingphotonluminositynecessarytoionizethehydrogengasintheseconesamountsto1057(photonss−1),whichislargerthanthatinthemajorityofradio-loudQSOs.Fromtheseresults,weproposethattheHαalignmenteffectinthisobjectisproducedbybiconicalgasclouds,whicharesweptupbythepassageofradiojets,andareionizedbystrongUVradiationfromahiddenAGN.Thecontinuumimageconsistsoftwocomponents,astellar-likepointsourceandanextendeddiffusegalaxy.Thesearesupposedtobeatype-2AGNanditshostgalaxy.TheSEDisfittedbyacombinationofspectraofareddeneddust-scatteredAGNandaninstantaneousstarburstpopulationof500Myrold.Thestellarmassofthegalaxyisestimatedtobe3×1011M⊙,whichisaslargeasthatoftypical3Cradiogalaxiesatz=1.

[学科分类] 天文学(综合)

[关键词] "AGN: ionization cone";"galaxies: active";"galaxies: individual (B3 0731+438)";"infrared: galaxies"