ASCA X-Ray Observations of the NGC 2023 and NGC 2024 Regions

[摘要] ThispaperpresentsthepropertiesofX-raysourcesintheregionsofNGC2023andNGC2024observedwithASCA.Wefound14point-likesourcesintheNGC2023field.IntheNGC2024field,ontheotherhand,wefoundextendedX-rayemissioninthecentraldustlaneofNGC2024,andresolved5point-likesourcesaroundthenebula.FromthepositionalcoincidenceandmoderatecolumndensityofNH∼1.6×1022Hcm−2,theextendedsourceismostlyattributabletoanintegratedemissionfromX-rayemittingyoungstellarobjects(YSOs)foundwithROSAT.However,theplasmatemperatureof∼4keVishigherthantheROSATresultsaswellasthoseofusualYSOs.Possiblecounterpartshavebeenfoundfortheotherresolvedsources,excepttwo;onehaslargeabsorptionatlowenergiesandtheotherhasmoderateabsorption.Theplasmatemperaturesandluminositiesfromthepointsources,exceptforanO-typestarζOriandastarexhibitingX-rayflares,areestimatedtobe∼1-5keVand1030.6−1031.5ergs−1inthe0.5−10.0keVenergyband(assumingthedistanceof400pc),respectively.WefoundnoX-raypeakatthepositionofaClass0protostar,NGC2023-MM1.

[学科分类] 天文学(综合)

[关键词] "ISM: individual (NGC 2023;NGC 2024)";"stars: pre-main sequence";"X-rays: sources";"X-rays: spectra";"X-rays: stars"