大质量恒星形成区IRAS 19213+1723的毫米/亚毫米波的观测和研究
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摘要
用KOSMA3米毫米/亚毫米波望远镜,对大质量恒星形成区IRAS19213+1723进行了12CO(2-1)和12CO(3-2)的成图观测.12CO(2-1)和12CO(3-2)的谱线轮廓均具有不对称的结构,且具有较大的线翼展宽.12CO(2-1)和12CO(3-2)积分强度图,进一步证实了IRAS19213+1723存在双极分子外向流,CO不同跃迁所示踪的此外向流形态相似.利用局部热动平衡(LTE)的方法,得到该外向流的总质量为15.0M⊙、平均动力学时标为5.0×105yr、总质量流失率为3.0×105M⊙yr1.最后计算出了12CO(3-2)与12CO(2-1)积分强度比和展示了积分强度比的分布,推断出该大质量恒星形成区中外向流存在高积分强度比可能是由外向流与其周围的星际介质互相作用的结果.
We have carried out12 CO(2-1) and12 CO(3-2) observations toward the high- mass star forming region IRAS19213+1723 with the KOSMA 3 m telescope.12 CO J=2-1 and12 CO J=3-2 lines both show asymmetric profiles with the broad wings. From the integrated intensity maps of12 CO(2-1) and12 CO(3-2), we further verified that there is outflow in this region. The outflow traced by CO different transitions is similar. Using LTE method, we derive that the mass, dynamic time scale, and mass loss rate of the outflow are15.0 M ⊙ , 5.0×10 5 yr, and 3.0×10 5 M ⊙ yr1 , respectively. Moreover, we calculate the integrated intensity ratio (I CO3-2 /I CO2-1 ) and show the distribution of the ratios, suggesting that the higher integrated intensity ratio (1.2) in the outflow, which all may be caused by the shock of the outflow.
We have carried out12 CO(2-1) and12 CO(3-2) observations toward the high- mass star forming region IRAS19213+1723 with the KOSMA 3 m telescope.12 CO J=2-1 and12 CO J=3-2 lines both show asymmetric profiles with the broad wings. From the integrated intensity maps of12 CO(2-1) and12 CO(3-2), we further verified that there is outflow in this region. The outflow traced by CO different transitions is similar. Using LTE method, we derive that the mass, dynamic time scale, and mass loss rate of the outflow are15.0 M ⊙ , 5.0×10 5 yr, and 3.0×10 5 M ⊙ yr1 , respectively. Moreover, we calculate the integrated intensity ratio (I CO3-2 /I CO2-1 ) and show the distribution of the ratios, suggesting that the higher integrated intensity ratio (1.2) in the outflow, which all may be caused by the shock of the outflow.
引文
1Shu F H,Adams F C,Lizano S.Star formation in molecular clouds-observation and theory.Annual Rev Astron Astrophys,1987,25:23-81
2Shepherd D S,Churchwell E.Bipolar molecular outflows in massive star formation regions.Astronphys J,1996,472:225-239
3Beuther H,Schilke P,Sridharan T K,et al.Massive molecular outflows.Astron Astronphys,2002,383:892-904
4Zhang Q,Hunter T R,Brand J,et al.Search for CO outflows toward a sample of69high-mass protostellar candidates:Frequency of occurrence.Astronphys J,2001,552:L167-L170
5Elitzur M,Hollenbach D J,McKee C F.H2O masers in star-forming regions.Astronphys J,1989,346:983-990
6Varricatt W P,Davis C J,Ramsay S,et al.A near-IR imaging survey of intermediate-and high-mass young stellar outflow candidates.MNRAS,2010,404:661-720
7Wu Y,Wei Y,Zhao M,et al.A study of high velocity molecular outflows with an up-to-date sample.Astron Astronphys,2004,426:503-515
8Zhang Q,Hunter T R,Brand J,et al.Search for CO outflows toward a sample of69high-mass protostellar candidates.II.Outflow properties.Astronphys J,2005,625:864-882
9Harju J,Lehtinen K,Booth R S,et al.A survey of SiO emission towards interstellar masers.I.SiO line characteristics.Astron Astronphys Suppl,1998,132:211-231
10Bronfman L,Nyman L A,May J.A CS(2-1)survey of IRAS point sources with color characteristics of ultra-compact HII regions.Astron Astronphys Suppl,1996,115:81-95
11Molinari S,Band J,Cesaroni R,et al.A search for precursors of ultra compact HII regions in a sample of luminous IRAS sources.I.Association with ammonia cores.Astron Astronphys,1996,308:573-587
12Szymczak M,Hrynek G,Kus A J.A survey of the6.7GHz methanol maser emission from IRAS sources.I.Data.Astron Astronphys Suppl,2000,143:269-301
13Palla F,Brand J,Cesaroni R,et al.Water masers associated with dense molecular clouds and ultracompact H II regions.Astron Astronphys,1991,246:249-263
14Wink J E,Altenhoff W J,Mezger P G,et al.Results of a radio survey for new compact H II regions.Astron Astronphys,1982,108:227-242
15Dickman R L.The ratio of carbon monoxide to molecular hydrogen in interstellar dark clouds.Astronphys J,1978,37:407-427
16Garden P R,Hayashi M,Hasegawa T,et al.A spectroscopic study of the DR21outflow source.III.The CO line emission.Astronphys J,1991,374:540-554
17Marti J,Rodriguez L F,Reipurth B.Proper motions of the inner condensations in the HH80-81thermal radio jet.Astronphys J,1998,502:337-341
18Qin S L,Wang J J,Zhao G,et al.Massive molecular outflows associated with UCHII/HII regions.Astron Astronphys,2008,484:361-369
19Xu J L,Wang J J,Miller M.Star formation associated with the Supernova Remnant IC443.Astronphys J,2011,721:81-87
20Xu J L,Wang J J,Miller M.Submillimeter/millimeter observations of the molecular clouds associated with Tycho’s supernova remnant.Res Astron Astronphys,2011,11:537-544
21Xu J L,Wang J J.The open cluster NGC6823and possible triggered star formation associated with SNR G59.5+0.1.Astron Astronphys,2012,543:A24-A31
22Xu J L,Wang J J.12CO J=2-1and12CO J=3-2observations toward the high-mass protostellar candidate IRAS20188+3928.Res Astron Astronphys,2013,13:39-46
23Wilson C D,Walker C E,Thornley M D.The density and temperature of molecular clouds in M33.Astronphys J,1997,483:210-229
24Sanders D B,Scoville N Z,Tilanus R P J,et al.A multi-transition CO and13CO survey of the Galactic Plane.In:Holt S,Verter F,eds.Back to the Galaxy.New York:AIP,1993.728:311-314
2Shepherd D S,Churchwell E.Bipolar molecular outflows in massive star formation regions.Astronphys J,1996,472:225-239
3Beuther H,Schilke P,Sridharan T K,et al.Massive molecular outflows.Astron Astronphys,2002,383:892-904
4Zhang Q,Hunter T R,Brand J,et al.Search for CO outflows toward a sample of69high-mass protostellar candidates:Frequency of occurrence.Astronphys J,2001,552:L167-L170
5Elitzur M,Hollenbach D J,McKee C F.H2O masers in star-forming regions.Astronphys J,1989,346:983-990
6Varricatt W P,Davis C J,Ramsay S,et al.A near-IR imaging survey of intermediate-and high-mass young stellar outflow candidates.MNRAS,2010,404:661-720
7Wu Y,Wei Y,Zhao M,et al.A study of high velocity molecular outflows with an up-to-date sample.Astron Astronphys,2004,426:503-515
8Zhang Q,Hunter T R,Brand J,et al.Search for CO outflows toward a sample of69high-mass protostellar candidates.II.Outflow properties.Astronphys J,2005,625:864-882
9Harju J,Lehtinen K,Booth R S,et al.A survey of SiO emission towards interstellar masers.I.SiO line characteristics.Astron Astronphys Suppl,1998,132:211-231
10Bronfman L,Nyman L A,May J.A CS(2-1)survey of IRAS point sources with color characteristics of ultra-compact HII regions.Astron Astronphys Suppl,1996,115:81-95
11Molinari S,Band J,Cesaroni R,et al.A search for precursors of ultra compact HII regions in a sample of luminous IRAS sources.I.Association with ammonia cores.Astron Astronphys,1996,308:573-587
12Szymczak M,Hrynek G,Kus A J.A survey of the6.7GHz methanol maser emission from IRAS sources.I.Data.Astron Astronphys Suppl,2000,143:269-301
13Palla F,Brand J,Cesaroni R,et al.Water masers associated with dense molecular clouds and ultracompact H II regions.Astron Astronphys,1991,246:249-263
14Wink J E,Altenhoff W J,Mezger P G,et al.Results of a radio survey for new compact H II regions.Astron Astronphys,1982,108:227-242
15Dickman R L.The ratio of carbon monoxide to molecular hydrogen in interstellar dark clouds.Astronphys J,1978,37:407-427
16Garden P R,Hayashi M,Hasegawa T,et al.A spectroscopic study of the DR21outflow source.III.The CO line emission.Astronphys J,1991,374:540-554
17Marti J,Rodriguez L F,Reipurth B.Proper motions of the inner condensations in the HH80-81thermal radio jet.Astronphys J,1998,502:337-341
18Qin S L,Wang J J,Zhao G,et al.Massive molecular outflows associated with UCHII/HII regions.Astron Astronphys,2008,484:361-369
19Xu J L,Wang J J,Miller M.Star formation associated with the Supernova Remnant IC443.Astronphys J,2011,721:81-87
20Xu J L,Wang J J,Miller M.Submillimeter/millimeter observations of the molecular clouds associated with Tycho’s supernova remnant.Res Astron Astronphys,2011,11:537-544
21Xu J L,Wang J J.The open cluster NGC6823and possible triggered star formation associated with SNR G59.5+0.1.Astron Astronphys,2012,543:A24-A31
22Xu J L,Wang J J.12CO J=2-1and12CO J=3-2observations toward the high-mass protostellar candidate IRAS20188+3928.Res Astron Astronphys,2013,13:39-46
23Wilson C D,Walker C E,Thornley M D.The density and temperature of molecular clouds in M33.Astronphys J,1997,483:210-229
24Sanders D B,Scoville N Z,Tilanus R P J,et al.A multi-transition CO and13CO survey of the Galactic Plane.In:Holt S,Verter F,eds.Back to the Galaxy.New York:AIP,1993.728:311-314