2019 July 8
The Galactic Center in Radio from MeerKAT
Image Credit: MeerKAT, SARAO
Explanation: What’s happening at the center of our galaxy? It’s hard to tell with optical telescopes since visible light is blocked by intervening interstellar dust. In other bands of light, though, such as radio, the galactic center can be imaged and shows itself to be quite an interesting and active place. The featured picture shows the inaugural image of the MeerKAT array of 64 radio dishes just completed in South Africa. Spanning four times the angular size of the Moon (2 degrees), the image is impressively vast, deep, and detailed. Many known sources are shown in clear detail, including many with a prefix of Sgr, since the Galactic Center is in the direction of the constellation Sagittarius. In our Galaxy’s Center lies Sgr A, found here just to the right of the image center, which houses the Milky Way’s central supermassive black hole. Other sources in the image are not as well understood, including the Arc, just to the left of Sgr A, and numerous filamentary threads. Goals for MeerKAT include searching for radio emission from neutral hydrogen emitted in a much younger universe and brief but distant radio flashes.
影像来源: MeerKAT, SARAO
说明：我们银河系的中心发生了什么？因为可见光被介于中间的星际尘埃所遮挡，所以我们用光学望远镜很难发现。然而，在其他光带中，例如射电波，银心能够被拍摄成像，并显示出它是一个非常有趣和活跃的地方。这幅特征影像是刚刚在南非建成、由64个射电天线组成的MeerKAT阵列拍摄的首张照片。它的角直径是月球的四倍（两度），其庞大、深邃和精细的结构令人印象深刻。因为银心位于人马座方向，所以许多已知的银心辐射源都非常清晰的呈现出来，包括许多前缀为Sgr的辐射源。我们银河系中心的人马座A（Sgr A）位于该影像中心的右侧，那里寄居着银河系中心特大质量黑洞。而影像中的其他辐射源还没有被很好地理解，包括位于Sgr A左侧的光弧和许多细丝结构。MeerKAT的目标包括寻找在更年轻宇宙中释放的中性氢所辐射出的射电波，以及短暂而遥远的射电闪光。