Far-Infrared Properties of Blue Compact Dwarf Galaxies Observed with AKARI/Far-Infrared Surveyor (FIS)

摘要

Wereportonthebasicfar-infrared(FIR)propertiesofeightbluecompactdwarfgalaxies(BCDs)observedbyAKARI.WehavemeasuredthefluxesatthefourFISbands(wavelengthsof65$$mu$$m,90$$mu$$m,140$$mu$$m,and160$$mu$$m).Basedonthesefluxes,wehaveestimatedbasicquantitiesofdust:dusttemperature,dustmass,andtotalFIRluminosity.WefindthatthetypicaldusttemperatureoftheBCDsampleissystematicallyhigherthanthatofnormalspiralgalaxies,althoughthereisalargevariety.Theinterstellarradiationfieldestimatedfromthedusttemperaturerangesupto100-timesthegalacticvalue.Thisconfirmstheconcentratedstar-formingactivityinBCDs.Thestar-formationratecanbeevaluatedfromtheFIRluminosityas0.01-0.5$$M_{odot}$$yr$$^{-1}$$.Combiningthisquantitywiththegasmasstakenfromtheliterature,wehaveestimatedthegasconsumptiontimescales(gasmassdividedbythestar-formationrate),whichhaveprovedtospanawiderangefrom1Gyrto100Gyr.Anaturalinterpretationofthislargevarietycanbeprovidedbyintermittentstar-formationactivity.Wefinallyshowtherelationbetweendust-to-gasratioandmetallicity(weutilizedourestimateofdustmass,andtookothernecessaryquantitiesfromtheliterature).Thereisapositivecorrelationbetweendust-to-gasratioandmetallicity,asexpectedfromchemicalevolutionmodels.