Nature of Infrared Sources in 11 $mu $m Selected Sample from Early Data of the AKARI North Ecliptic Pole Deep Survey

[摘要] Wepresentthepropertiesof11$$mu$$mselectedsourcesdetectedintheearlydataoftheNorthEclipticPoleDeep(NEP-Deep)SurveyofAKARI.Thedatasetcovers6wavelengthbandsfrom2.5to11$$mu$$m,withexposuretimesof10–20minutes.ThisfieldlieswithintheCFHTsurveywithfourfilterbands($$g^prime,r^prime,i^prime,z^prime$$),enablingustoestablishnearlycontinuousspectralenergydistributions(SEDs)forwavelengthsrangingfrom0.4to11$$mu$$m.Themainsamplestudiedhereconsistsof72sourceswhose11$$mu$$mABmagnitudesareequaltoorbrighterthan18.5(144$$mu$$Jy),whichiscompletetomorethan90%.The11$$mu$$mbandhasanadvantageofsamplingstar-forminggalaxieswithlow-to-mediumredshifts,sincetheprominentPAHfeatureshiftsintothisband.Asexpected,wefindthatthemajority(71%)of11$$mu$$mbrightsourcesarestar-forminggalaxiesat$$0.2lesssimzlesssim0.7$$with$$L_{mIR}sim10^{10}-10^{12}~L_{odot}$$basedondetailedmodellingoftheSEDs.WealsofindfourAGNslyingatvariousredshiftsinthemainsample.Inaddition,wediscussafewsourcesthathavenon-typicalSEDsofthemainsample,includingabrown-dwarfcandidate,asteeppower-lawsource,aflat-spectrumobject,andanearly-typegalaxyatmoderateredshift.

[学科分类] 天文学(综合)

[关键词] "galaxies: active";"galaxies: evolution";"galaxies: formation";"infrared: galaxies";"stars: low-mass"