Starbirth region NGC 604. Combined Hubble Space Telescope (HST) and Chandra X-ray Observatory (CXO) image of NGC 604, the largest region of star formation in the nearby galaxy M33. The colours indicate the radiation detected: X-rays (blue) and visible light (red and green). This area contains gas and dust heated and stirred by some 200 massive young stars. NGC 604 is located in the constellation of Triangulum and is around 2.7 million light years from Earth. The area seen here is around 900 light years across. This image was obtained in 2001 as part of a detailed observation of M33 called the Chandra ACIS Survey of M33, or ChASeM33.