Dissolve from Optical to X-ray View of NGC 4555
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This sequence begins with a wide-field optical view of the region surrounding NGC 4555, which includes the large spiral galaxy NGC 4565 (also known as the "Needle Galaxy"). It then dissolves into Chandra's X-ray image of the elliptical galaxy NGC 4555. The hot gas cloud seen in X-rays is about 400,000 light years in diameter, or twice the size of the galaxy seen in visible light. This reveals that an enormous envelope, or halo, of dark matter is needed to confine the hot cloud to the galaxy.
[Run time = 0:18 sec]
Credit: X-ray: NASA/CXC/E.O'Sullivan et al; Optical: Palomar DSS