Polarimetry of near-infrared flares from Sagittarius A*
Polarimetry of near-infrared flares from Sagittarius A*
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DOI：
10.1051/0004-6361:20064948
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发表时间：
2006-08
影响因子：
6.5
通讯作者：
A. Eckart;R. Schödel;L. Meyer;S. Trippe;T. Ott;R. Genzel
中科院分区：
文献类型：
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作者：
A. Eckart;R. Schödel;L. Meyer;S. Trippe;T. Ott;R. Genzel
上下文我们报告了与银河系中心的大质量3- 4\times10^6 $ $M_{\odot}$黑洞相关的SgrA* 对应物的可变近红外发射的新偏振测量。目标。我们调查的物理过程负责的变量发射SgrA*。方法.这些观测是使用欧洲南方天文台甚大望远镜的纳科自适应光学（AO）仪器进行的。结果我们发现，可变的近红外发射的SgrA* 是高度偏振的，由一个非或弱偏振的主耀斑与高度偏振的子耀斑的贡献。耀斑活动显示出可能的准周期性$20\pm3$ min与以前的观测结果一致。结论.高度可变和偏振的发射支持NIR发射是非热的。观测结果可以用喷流或临时盘模型来解释。在圆盘模型中，准周期性的通量密度变化可以用围绕中心MBH的相对论轨道上的斑点来解释。关于玻色子或费米子球的高中心质量集中的其他解释越来越不可能。
Context. We report new polarization measurements of the variable near-infrared emission of the SgrA* counterpart associated with the massive 3–$4\times10^6$ $M_{\odot}$ Black Hole at the Galactic Center. Aims. We investigate the physical processes responsible for the variable emission from SgrA*. Methods. The observations have been carried out using the NACO adaptive optics (AO) instrument at the European Southern Observatory's Very Large Telescope. Results. We find that the variable NIR emission of SgrA* is highly polarized and consists of a contribution of a non- or weakly polarized main flare with highly polarized sub-flares. The flare activity shows a possible quasi-periodicity of $20\pm3$ min consistent with previous observations. Conclusions. The highly variable and polarized emission supports that the NIR emission is non-thermal. The observations can be interpreted in a jet or temporary disk model. In the disk model the quasi-periodic flux density variations can be explained by spots on relativistic orbits around the central MBH. Alternative explanations for the high central mass concentration involving boson or fermion balls are increasingly unlikely.