Japanese VLBI Network Observations of Radio-Loud Narrow-Line Seyfert 1 Galaxies

[摘要] Weperformedphase-referenceverylongbaselineinterferometry(VLBI)observationsonfiveradio-loudnarrow-lineSeyfert1galaxies(NLS1s)at8.4GHzwiththeJapaneseVLBINetwork.Eachofthefivetargets(RXSJ08066$$+$$7248,RXSJ16290$$+$$4007,RXSJ16333$$+$$4718,RXSJ16446$$+$$2619,andB31702$$+$$457)inmilli-Janskylevelsweredetectedandunresolvedinmilli-arcsecondresolutions,i.e.,withbrightnesstemperatureshigherthan$$10^7$$K.Thenonthermalprocessesofactivegalacticnucleusactivity,ratherthanstarbursts,arepredominantlyresponsiblefortheradioemissionsfromtheseNLS1s.Outofthenineknownradio-loudNLS1s,includingthosechosenforthisstudy,wefoundthatthefourmostradio-loudobjectsexclusivelyhaveinvertedspectra.ThissuggestsapossibilitythattheseNLS1sareradio-loudduetoDopplerbeaming,whichcanapparentlyenhanceboththeradiopowerandthespectralfrequency.

[学科分类] 天文学(综合)

[关键词] "galaxies: active";"galaxies: jets";"galaxies: Seyfert";"radio continuum: galaxies";"techniques: interferometric"