A Multi-wavelength Study of the Massive Black Hole Sagittarius A* at the Galactic Center

Yusef-Zadeh博士将使用多波长时间序列观测来测试两个模型，以解释在银河系中央射电源中观察到的耀斑。 根据“等离子体激元”模型，无线电明亮物质的斑点从中心黑洞向外移动，随着它们对自己的同步辐射变得光学薄，在连续更长的波长处变亮。 如果耀斑是由黑洞周围吸积盘中的热点引起的，那么光源应该在所有波长上同时变亮。 在北方和南方的天空都将使用单碟望远镜进行亚毫米观测，在厘米波长处使用射电望远镜阵列，以测量几天内的总强度和偏振。 2007年两次这样的活动的数据现在已经掌握，另一次包括美国宇航局钱德拉太空望远镜在X射线中的观测的数据定于2008年中期进行。未来的活动可能包括来自欧空局赫歇尔太空望远镜的中红外数据。 还将使用来自超大阵列的存档数据。 理论工作将包括等离子体模型的扩展，以预测各向异性发射区产生的偏振。Yusef-Zadeh博士开发了一个交互式网络客户端，为本科生和成人教育课程提供基于问题的练习。 他将围绕该项目为该系统开发进一步的练习。 他还将继续协调跨学科的科学讲座计划，为公众，在阿德勒天文馆任教，并让学生参与公共宣传。 博士后将通过参与研究进行培训。

Dr Yusef-Zadeh will use multiwavelength time-series observations to test two models to explain the flaring observed in the Milky Way's central radio source. According to the 'plasmon' model, blobs of radio-bright material move outwards from the central black hole, brightening at successively longer wavelengths as they become optically thin to their own synchrotron radiation. If the flares are instead caused by hot-spots in an accretion disk around the black hole, the source should brighten simultaneously at all wavelengths. Sub-millimeter observations would be taken in both the northern and southern sky with single-dish telescopes, and radio-telescope arrays would be used at centimeter wavelengths, to measure both total intensity and polarization over periods of several days. Data from two such campaigns in 2007 is now in hand, and another that includes observations with NASA's Chandra space telescope in the X-ray is scheduled for mid-2008. Future campaigns may include mid-infrared data from ESA's Herschel space telescope. Archival data from the Very Large Array will also be used. Theoretical work will include an extension of the plasmon model to predict polarization that arises from the anisotropic emitting region.Dr. Yusef-Zadeh has developed an interactive web client with problem-based exercises for undergraduate and adult-education classes. He will develop further exercises for this system, based around this project. He will also continue to coordinate a program of interdisciplinary science lectures for the public, to teach at Adler Planetarium, and to involve students in public outreach. A postdoc will be trained through involvement in the research.