Narrator (Megan Watzke, CXC): The galaxy NGC 4258 has its arms crossed. At least it appears that it does. A composite image of this spiral galaxy, about 25 million light-years from Earth, shows an X-shaped pattern when seen in different types of light. Infrared radiation from the Spitzer Space Telescope and optical light data from the Digitized Sky Survey show one set of arms, which are made from stars and dust from the galaxy. However, x-ray data from the Chandra X-ray Observatory and radio emission from the Very Large Array reveal a different pair of arms. These dislocated arms are the result of shockwaves, generated by the giant black hole in the center of NGC 4258.
Revised: September 19, 2008