Hubble's view of NGC 604
A view of NGC 604, a star-forming region located in the M33 galaxy, taken with the NASA/ESA Hubble Space Telescope.
Some 1500 light-years across, this is one of the largest, brightest concentrations of ionised hydrogen (H II) in our local group of galaxies, and is a major centre of star formation.
The gas in NGC 604, around nine tenths of it hydrogen, is gradually collapsing under the force of gravity to create new stars. Once these stars have formed, the vigorous ultraviolet radiation they emit excites the remaining gas in the cloud, making it glow a distinct shade of red. This colour is typical not only of NGC 604 but of other H II regions too.
This image was created from images taken using the High Resolution Channel of Hubble's Advanced Camera for Surveys. It is a composite of images taken through a total of seven different filters spanning a huge range of wavelengths — from 220 nm in the ultraviolet all the way up to the near infrared at one micron. The field of view is about 31 by 22 arcseconds.