Two-Epoch Space VLBI Observations of the Gamma-Ray Loud Quasar PKS 1741–038

[摘要] Wepresenttheresultsofhigh-resolutionimagingofthegamma-rayloudquasarPKS1741–038withtheHALCAsatelliteandgroundradiotelescopes.Observationsweremadeattwoepochsatanintervalofninemonthswiththefirst-epochobservationat1.6and5GHzandwiththesecond-epochobservationat5GHz.Thesourceshowsaverycompactstructure,butisclearlyresolvedinthespace-groundbaselinevisibilitydata.Thecorecomponentofthesourcehasabrightnesstemperature,Tb,greaterthan1012Kinthesource'srestframeateachfrequency.WeappliedthreeindividualjetmodelsinordertoderivetheDopplerfactor,δ.Thecorecomponenthasδ∼14,consideringtheTblimitduetotheinverseComptoncatastrophe,whilea2.5-timeslargerδisobtainedassumingthattheparticlesandmagneticfieldareinequipartition.Two-epochimagesat5GHzshowalmostnochangeofthestructure.Assumingthatthecomponentmotioninthisintervalislessthanourresolution,wederivedtheupperlimitoftheviewingangleasbeing4.°8.ThesmallerviewingangleandhigherDopplerfactorfavortheinverseComptongamma-rayemissionmodel;weconcludethatthegamma-rayemissionfromthissourceishighlyDoppler-boosted.

[学科分类] 天文学(综合)

[关键词] "galaxies: active";"galaxies: nuclei";"quasars: individual (PKS 1741-038)"