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观察到的耀斑。根据“等离子激元”模型，射电明亮的物质从中央黑洞向外移动，随着它们在自身的同步辐射下变得光学上变薄，它们在更长的波长上连续变亮。相反，如果耀斑是由黑洞周围吸积盘中的热点引起的，那么源应该在所有波长上同时变亮。将使用单碟式望远镜在北部和南部天空进行亚毫米级的观测，并使用厘米波长的射电望远镜阵列，以测量几天的总强度和偏振。2007年的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对X射线的观测计划在2008年年中进行。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。还将使用超大型阵列中的归档数据。理论工作将包括等离子体激元模型的扩展，以预测各向异性发射区产生的偏振。Yusef-Zadeh已经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。他将围绕这个项目，为这个系统开发更多的练习。他还将继续协调面向公众的跨学科科学讲座计划，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.