(Sen) - A powerful new instrument called KMOS has arrived in Chile to help make rapid advances in astronomers' knowledge of the earliest galaxies in the Universe.
The complex, high-tech device, which will be bolted on to one of the telescopes that make up the European Southern Observatory's Very Large Telescope (VLT), was assembled in the UK.
This Sen writer was invited to the Astronomy Technology Centre at the Royal Observatory, Edinburgh, in June to see the amazing instrument, which cost $24 million to build. KMOS, which stands for K-Band Multi Object Spectrometer, has 24 super-cooled robotic arms.
It has the ability to pick out 24 different galaxies simultaneously in a single view with the VLT and discover the properties of each one. A process that would have taken many years before can now be accomplished in just two months.
KMOS, which weighs eight and a half tons, will be able to look back more than 13 billion years to see the first stars turn on in the darkness that came after the Big Bang - a time termed the reionization epoch.
An image of each galaxy will be sliced and diced, then fed through one of three spectrometers to give a 3D picture revealing what each galaxy is made of and how it is spinning. This will help astronomers learn how the first galaxies evolved to become like those we see around us today.
Systems engineer Phil Rees, who led the team building KMOS, told Sen: “For every pixel in the image, you’re getting the composition of the galaxy, the chemical elements in it, and also its velocity, so you can see how it is moving, how it is spinning, if bits are flying out of it and what they’re made out of."
There are more than 1,500 tiny, diamond-cut, gold-plated mirrors in KMOS which will be chilled to a temperature of 100 degrees Kelvin (-170 C) to work at infrared wavelengths of light, using 56 separate cryogenic mechanisms.
The intense cold, produced using liquid nitrogen then helium, is necessary to stop warmth from the apparatus from interfering with the faint signals from space. It will take a week to cool down to the temperature needed.
An engineer inspects KMOS with its array of 24 robotic arms. Credit: ATC
Universities and institutions in the UK and Germany worked together to build KMOS. Astronomer Michele Cirasuolo, instrument scientist for KMOS at Edinburgh, said: “Until now you could only observe one object at a time. It was really time consuming. If you wanted to observe a large number of galaxies it would take years. That’s why KMOS is really needed.
“If you look at the local Universe, you see a lot of dark galaxies, some of them are round elliptical galaxies, some of them are spirals, some of them are still forming and some of them are dead. So we see them but we don’t know why they are like that. But if we go back in time you can trace them as they start forming, merging and assembling their stars."
KMOS, which arrived at ESO's Paranal site on September 1, has spent six weeks being re-assembled, cooled down and tested in a special assembly hall. All the tests went well and now the instrument is ready to be moved to VLT Unit 1, known as Antu.
On November 6, KMOS will be transported from the assembly hall to the telescope, using one of the largest cranes in Chile. It will then take two weeks to connect KMOS to the telescope. The first observation - dubbed "first light" - is expected on November 22-23 and two weeks of observations will be used to check the alignments and initial performances.
More tests in mid-January will be followed by the first science observations as astronomers begin to unravel the earliest secrets of the Universe.