Hubble telescope observes the farthest space

Using the Hubble telescope Leiden astronomer Rychard Bouwens has been able to observe deeper into space than ever before. A recording of no less than 87 hours has shown the universe when it was just 480 million years old. An article on the observations will appear in Nature on 27 January.

Just one candidate

To his surprise, Bouwens found just one candidate galaxy at this record distance: ‘It’s surprising because we see a lot of galaxies from the time that the universe was slightly older (630 million years old). We have been able to observe more than 40 galaxies of the same age. The indication is that the universe experienced strong evolutionary activity when it was very young.’ The fact that just one galaxy has been found is direct evidence that galaxies grew very rapidly in the young universe. Using the Hubble telescope Leiden astronomer Rychard Bouwens has been able to observe deeper into space than ever before. A recording of no less than 87 hours has shown the universe when it was just 480 million years old. An article on the observations will appear in Nature on 27 January.

Just one candidate

To his surprise, Bouwens found just one candidate galaxy at this record distance: ‘It’s surprising because we see a lot of galaxies from the time that the universe was slightly older (630 million years old). We have been able to observe more than 40 galaxies of the same age. The indication is that the universe experienced strong evolutionary activity when it was very young.’ The fact that just one galaxy has been found is direct evidence that galaxies grew very rapidly in the young universe.

Bouwens: ‘This rapid evolution indicates that we are really looking back to the time when the first galaxies were formed in the universe. It’s as if we are seeing the very start of the start.’ The distant galaxy (at a so-called redshift of 10) is very weak and it can only be detected with more sensitive recordings. It seems to weigh very little: it has less than 1/100th of the mass of our Milky Way.’

Dark Ages

Before this galaxy existed the universe was mainly ‘dark’. This Dark Ages started when at an age of around 400,000 years the universe had cooled off sufficiently to become transparent. At that time it consisted of a homogeneous distribution of matter. Gravity gradually caused the formation of galaxies. the first galaxies that astronomers were able to observe being formed just 400 million years later. Co-author Marijn Franx (Leiden Observatory) explains: ‘These first galaxies are very interesting because they were formed in a universe that had not yet been polluted by star formation. Its probably had characteristics that were completely different from the galaxies that are formed today.’

Ultra-long light

Bouwens carried out the research with a team of colleagues, including from the University of California Santa Cruz and Yale. Using the Hubble telescope, the team made the most sensitive recording ever achieved in the near infrared. We are unable to observe this colour with our naked eyes, but it can be recorded by the Hubble telescope with its brand new highly sensitive camera. Over a period of a year, the Hubble telescope observed the same position in the heavens for 87 hours. As the galaxies are so distant, the light is very weak and even the Hubble camera can only find galaxies at long wavelengths. The light from these galaxies has been more than 13 billion years en route. The astronomers can now see how the universe looked when it was much younger than today.

Future studies

The astronomers are not yet able to deduce a great deal from the recordings. ‘So far we only have a first impression; we need other telescopes to be able to make further studies of these fascinating galaxies,’ says Professor Marijn Franx. He and co-author Garth Illingworth (University of California, Santa Cruz) are involved in the development of the successor to the Hubble, the James Webb Space Telescope, that will be capable of making much more precise measurements of these galaxies.

Links – Oldest galaxy is lone ranger, 26 januari 2011 – Spinoza winner Marijn Franx to use the successor to the Hubble