1.3 mm WAVELENGTH VLBI OF SAGITTARIUS A*: DETECTION OF TIME-VARIABLE EMISSION ON EVENT HORIZON SCALES
1.3 mm WAVELENGTH VLBI OF SAGITTARIUS A*: DETECTION OF TIME-VARIABLE EMISSION ON EVENT HORIZON SCALES
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DOI：
10.1088/2041-8205/727/2/l36
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发表时间：
2010-11
期刊：
影响因子：
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通讯作者：
V. Fish;S. Doeleman;C. Beaudoin;R. Blundell;D. E. Bolin;G. Bower;R. Chamberlin;R. Freund;P. Frib
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文献类型：
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作者：
V. Fish;S. Doeleman;C. Beaudoin;R. Blundell;D. E. Bolin;G. Bower;R. Chamberlin;R. Freund;P. Frib
人马座A* 是银河系中心的一个104 × 106 M的黑洞候选者，可以用（亚）毫米波长甚长基线干涉测量法（VLBI）在史瓦西半径尺度上进行研究。我们报告的1.3毫米波长的观测Sgr A* 使用的VLBI阵列组成的JCMT莫纳克亚山，亚利桑那州射电天文台的亚毫米望远镜山。格雷厄姆在亚利桑那州，和两个望远镜的CARMA阵列在雪松平原在加州。Sgr A* 和类星体校准器1924−292都在连续三个晚上被观测到，并且在所有基线上都能清楚地检测到这两个源。首次通过测量基线三角形上的闭合相位，提取了Sgr A* 上1.3mm VLBI干涉仪的相位信息。在观测的第三个晚上，所有VLBI基线上的Sgr A* 的相关通量密度相对于前两个晚上增加，为几个史瓦西半径尺度上的时变变化提供了强有力的证据。这些结果表明，未来的VLBI观测与更高的灵敏度和额外的基线将发挥有价值的作用，在确定结构的事件视界附近的Sgr A* 的排放。
Sagittarius A*, the ∼4 × 106 M☉ black hole candidate at the Galactic center, can be studied on Schwarzschild radius scales with (sub)millimeter wavelength very long baseline interferometry (VLBI). We report on 1.3 mm wavelength observations of Sgr A* using a VLBI array consisting of the JCMT on Mauna Kea, the Arizona Radio Observatory's Submillimeter Telescope on Mt. Graham in Arizona, and two telescopes of the CARMA array at Cedar Flat in California. Both Sgr A* and the quasar calibrator 1924−292 were observed over three consecutive nights, and both sources were clearly detected on all baselines. For the first time, we are able to extract 1.3 mm VLBI interferometer phase information on Sgr A* through measurement of closure phase on the triangle of baselines. On the third night of observing, the correlated flux density of Sgr A* on all VLBI baselines increased relative to the first two nights, providing strong evidence for time-variable change on scales of a few Schwarzschild radii. These results suggest that future VLBI observations with greater sensitivity and additional baselines will play a valuable role in determining the structure of emission near the event horizon of Sgr A*.