Polarized near-infrared light of the Dusty S-cluster Object (DSO/G2) at the Galactic center
Polarized near-infrared light of the Dusty S-cluster Object (DSO/G2) at the Galactic center
复制标题
银河中心尘埃 S 星团天体 (DSO/G2) 的偏振近红外光
DOI：
10.1051/0004-6361/201628994
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发表时间：
2016
影响因子：
6.5
通讯作者：
C. Straubmeier
中科院分区：
文献类型：
--
作者：
B. Shahzamanian;A. Eckart;M. Zajaček;M. Valencia;N. Sabha;L. Moser;M. Parsa;F. Peißker;C. Straubmeier
我们研究了一个名为G2或尘埃S星团对象的红外超额源，它在银河系中央黑洞SgrA*的高度偏心轨道上运动。我们首次利用近红外偏振成像数据来确定数字示波源的性质和性质，并在不同观测年份的中值偏振图像上获得了对该震源的改进的K-S波段识别。该源在2008年开始偏离恒星混乱，在我们分析它的几年中，它没有显示出任何通量密度变化。我们在2008-2012年间测量了DSO的偏振度和偏振角，通过对偏振参数的显著性分析，得出结论：它是一个本征偏振源(>；20%)，当它接近SGR A*的位置时，偏振角是变化的。数字示波仪显示了K S−L的近红外过量，在其轨道近心附近保持着致密的状态。它的观测参数和在这项工作中获得的显著偏振表明，DSO可能是一颗尘埃笼罩的年轻恒星，在接近超大质量黑洞时形成弓形激波。测量到的显著高的偏振度表明它具有非球面几何形状，它可以被模拟为弓形激波和恒星的两极风的组合。我们使用了一个三维辐射传输模型，该模型可以再现观测到的源的性质，如总通量密度和偏振度。我们得出，偏振角的变化可以归因于源结构的本征变化。年轻恒星在黑洞引力场中的吸积盘进动会导致两极外流的变化，从而导致极化角的变化。它也可能是源与环境介质相互作用的结果。
We investigate an infrared-excess source called G2 or Dusty S-cluster Object (DSO), which moves on a highly eccentric orbit around the Galaxy’s central black hole, Sgr A*. We use, for the first time, near-infrared polarimetric imaging data to determine the nature and properties of the DSO and obtain an improved K s -band identification of this source in median polarimetry images of different observing years. The source started to deviate from the stellar confusion in 2008, and it does not show any flux density variability over the years we analyzed it. We measured the polarization degree and angle of the DSO between 2008 and 2012 and conclude, based on the significance analysis on polarization parameters, that it is an intrinsically polarized source (> 20%) with a varying polarization angle as it approaches the position of Sgr A*. The DSO shows a near-infrared excess of K s − L ′ > 3 that remains compact close to the pericenter of its orbit. Its observed parameters and the significant polarization obtained in this work show that the DSO might be a dust-enshrouded young star, forming a bow shock as it approaches the super massive black hole. The significantly high measured polarization degree indicates that it has a non-spherical geometry, and it can be modeled as a combination of a bow shock with a bipolar wind of the star. We used a 3D radiative transfer model that can reproduce the observed properties of the source such as the total flux density and the polarization degree. We obtain that the change of the polarization angle can be due to an intrinsic change in the source structure. Accretion disk precession of the young star in the gravitational field of the black hole can lead to the change of the bipolar outflow and therefore the polarization angle variation. It might also be the result of the source interaction with the ambient medium.
DOI：
10.1088/0004-637x/750/1/58
发表时间：
2012-01
期刊：
The Astrophysical Journal
影响因子：
--
作者：
A. Burkert;M. Schartmann;C. Alig;S. Gillessen;R. Genzel;T. Fritz;F. Eisenhauer
通讯作者：
A. Burkert;M. Schartmann;C. Alig;S. Gillessen;R. Genzel;T. Fritz;F. Eisenhauer