A Galactic Center 50-kms$^{-1}$ Molecular Cloud with an Expanding Shell

Publications of the Astronomical Society of Japan

Tsuboi, Masato³  Okumura, Sachiko K.¹  Miyazaki, Atsushi² 

[1] National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588;Mizusawa VERA Observatory, National Astronomical Observatory of Japan, Mizusawa, Oshu, Iwate 023-0861;Institute of Space and Astronautical Science, JAXA, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 Department of Astronomy, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033

关键词: Galaxy;    "molecular cloud";    "supernova remnant";   

DOI  :  10.1093/pasj/61.1.29

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

Weperformedhigh-resolutionobservationsofaGalacticCenter50-km s$$^{-1}$$molecularcloudintheCS$$J$$$$=$$1–0lineusingtheNobeyamaMillimeterArray(NMA).Themolecularcloudmainlyhasthreedifferentspatialcomponentswithlargevelocitywidthsofupto60kms$$^{-1}$$.ThenorthwestcomponentislocatedatanapparentcontactpointtotheSgrAeastshell,andelongatedalongtheboundaryoftheshell.ThelargevelocitywidthofthecomponentisresponsibleforinteractionwiththeSgrAeastshell.ThemoleculargasdistributioninCSlineemissionisdissimilartothatobservedpreviouslyinNH$$_3$$lineemissions.TheappearanceshowspresumablytheareaofCSlineemissionenhancedbyshock.ThecentralandsouthwestcomponentsarelocatedjustoutoftheSgrAeastshellandfarfromit,respectively.However,thesecomponentshavelargevelocitywidths.Wefoundawell-shapedcircularmolecularshellwithexpandingmotioninthe50-km s$$^{-1}$$molecularcloud.Thisisresponsibleforthelargevelocitywidth.Thecontinuumsourceintheexpandingmolecularshellhasasteepspectruminmm-wavelengths,althoughthiswasnotidentifiedinaprevious5-GHzmap.ThissourcemaybeanSNRwithanionizedsheath.Fromtheaspectratioofanexpandingmolecularshellof1.1,themagneticfieldin/aroundtheshellisestimatedtobesmallerthan100$$mu$$Gauss.Thisweakmagneticfieldisconsistentwithon-goingactivestarformationinthe50-km s$$^{-1}$$molecularcloud.AcomparisonamongCSlineemission,low-frequencycontinuum,andmillimetercontinuumtowardthe50-km s$$^{-1}$$molecularcloudsuggestsaface-onviewoftheSgrAregion.ThemolecularcloudislocatedintheSgrAhaloregion.

【 授权许可】

Unknown