Composite of the galaxy image (left) and the spectrum (right)

A colour image (left) of a spiral galaxy in the Hubble Ultra Deep Field, one of the targets included in the Hubble Legacy Archive (HLA) release of slitless spectra from the Advanced Camera for Surveys (ACS). The colour picture was created from ACS images taken through the broadband filters F435W, F606W, F775W and F850LP. The galaxy is a typical spiral with a yellow stellar body and blue-white knots. While the image reveals the colour of the knots, it does not reveal their physical nature. The slitless spectrum (right) provides a one-shot spectrum of the whole galaxy and its constituent parts by spreading all the light in the image into its component colours. The spectrum, formed by combining many exposures with a total exposure time of 22 500 s, shows that the knots shine with very strong emission lines of doubly ionised oxygen (highlighted in green) and hydrogen (highlighted in red), revealing that these are regions of star formation in which the gas is heated by massive stars, as is typical in our own Milky Way and similar spirals. A redshift of 0.42 can be measured from the emission lines in the spectrum, meaning that the galaxy’s light has taken about 4 billion years to reach us.

Credit:

ESA/Hubble and NASA

About the Image

Id:ann1009a
Type:Collage
Release date:4 August 2010, 15:00
Related announcements:ann1009
Size:1199 x 505 px

About the Object

Name:Hubble Ultra Deep Field, HUDF
Type:• Early Universe : Galaxy
• Early Universe : Cosmology : Morphology : Deep Field
• X - Galaxies Images/Videos
• X - Cosmology Images/Videos

Colours & filters

BandWavelengthTelescope
Optical Hubble Space Telescope
ACS
Optical
B
435 nm Hubble Space Telescope
ACS
Optical
V
606 nm Hubble Space Telescope
ACS
Optical
R
775 nm Hubble Space Telescope
ACS
Infrared
Z
850 nm Hubble Space Telescope
ACS

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