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首页> 外文期刊>The Astrophysical journal >ISOLATED, MASSIVE SUPERGIANTS NEAR THE GALACTIC CENTER
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ISOLATED, MASSIVE SUPERGIANTS NEAR THE GALACTIC CENTER

机译:银河中心附近隔离的大量上级

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We have carried out a pilot project to assess the feasibility of using radio, infrared, and X-ray emission to identify young, massive stars located between 1 and 25 pc from the Galactic center. We first compared catalogs compiled from the VLA, Chandra, and 2MASS. We identified two massive, young stars: the previously identified star that is associated with the radio H II region H2 and a newly identified star that we refer to as CXOGC J174516.1-290315. The infrared spectra of both stars exhibit very strong Brγ and He I lines and resemble those of massive supergiants that have evolved off of the main sequence but not yet reached the Wolf-Rayet phase. We estimate that each star has a bolometric luminosity approx >10~6 solar luminosity. These two stars are also associated with bright mid-infrared sources from the MSX survey, although the origin of this emission is uncertain. Likewise, the detection of these two sources in X-rays is surprising because stars at similar evolutionary states are not uniformly bright X-ray sources. Therefore, we suggest that both stars are in binary systems that contain either OB stars whose winds collide with those of the luminous supergiants or compact objects that are accreting from the winds of the supergiants. We also identify X-ray emission from a nitrogen-type Wolf-Rayet star and place upper limits on the X-ray luminosities of three more evolved, massive stars that previously have been identified between 1 and 25 pc from Sgr A~*. Finally, we briefly discuss the implications that future searches for young stars will have for our understanding of the recent history of star formation near the Galactic center.
机译:我们已经执行了一个试点项目,以评估使用无线电,红外和X射线发射来识别距银河系中心1至25 pc之间的年轻大质量恒星的可行性。我们首先比较了从VLA,Chandra和2MASS编译的目录。我们确定了两颗大质量的年轻恒星:先前确定的与无线电H II区域H2相关的恒星,以及新近确定的恒星,我们称为CXOGC J174516.1-290315。两颗恒星的红外光谱都显示出很强的Brγ和He I线,类似于已经脱离主要序列但尚未到达Wolf-Rayet相的巨型超巨星的红外光谱。我们估计每颗恒星的辐射热度约为> 10〜6太阳光度。尽管这颗星的起源尚不确定,但这两颗星还与来自MSX调查的明亮的中红外源有关。同样,在X射线中检测到这两个源也是令人惊讶的,因为处于类似演化状态的恒星并不是均匀地明亮的X射线源。因此,我们建议两颗恒星都处于双星系统中,它们既包含OB恒星,其风与发光超级巨人的风相撞,也包括紧凑物体从超级巨人的风中积聚。我们还确定了氮型Wolf-Rayet恒星发出的X射线,并将上限确定为另外三个已演化的大质量恒星的X射线光度,这些恒星先前已从Sgr A〜*确定为1至25 pc。最后,我们简要讨论了未来搜寻年轻恒星将对我们了解银河系中心附近恒星形成的最新历史所产生的影响。

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