ALMA: Ancient Stardust Sheds Light on the First Stars

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bystander
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ALMA: Ancient Stardust Sheds Light on the First Stars

Post by bystander » Wed Mar 08, 2017 3:32 pm

Ancient Stardust Sheds Light on the First Stars
ALMA | ESO | NAOJ | NRAO | UCL | 2017 Mar 08

Most Distant Object Ever Observed by ALMA

Astronomers have used ALMA to detect a huge mass of glowing stardust in a galaxy seen when the Universe was only four percent of its present age. This galaxy was observed shortly after its formation and is the most distant galaxy in which dust has been detected. This observation is also the most distant detection of oxygen in the Universe. These new results provide brand-new insights into the birth and explosive deaths of the very first stars.

An international team of astronomers, led by Nicolas Laporte of University College London, have used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe A2744_YD4, the youngest and most remote galaxy ever seen by ALMA. They were surprised to find that this youthful galaxy contained an abundance of interstellar dust — dust formed by the deaths of an earlier generation of stars.

Follow-up observations using the X-shooter instrument on ESO’s Very Large Telescope confirmed the enormous distance to A2744_YD4. The galaxy appears to us as it was when the Universe was only 600 million years old, during the period when the first stars and galaxies were forming. ...

Cosmic dust is mainly composed of silicon, carbon and aluminium, in grains as small as a millionth of a centimetre across. The chemical elements in these grains are forged inside stars and are scattered across the cosmos when the stars die, most spectacularly in supernova explosions, the final fate of short-lived, massive stars. Today, this dust is plentiful and is a key building block in the formation of stars, planets and complex molecules; but in the early Universe — before the first generations of stars died out — it was scarce. ...

The detection of dust in the early Universe provides new information on when the first supernovae exploded and hence the time when the first hot stars bathed the Universe in light. Determining the timing of this “cosmic dawn” is one of the holy grails of modern astronomy, and it can be indirectly probed through the study of early interstellar dust. ...

Dust in the Reionization Era: ALMA Observations of a z = 8.38 Galaxy - Nicolas Laporte et al
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Re: ALMA: Ancient Stardust Sheds Light on the First Stars

Post by Ann » Wed Mar 08, 2017 11:36 pm

Wow, that's a spectacular image! The plethora of galaxies visible across the length and breadth of this image is fantastic. I think I can see one galaxy being lensed at least three times in the lower left part of the image.

But I can see nothing in the non-enlarged box at upper left. Are we supposed to see something in there? Or did it take computers and ALMA to tease out what even NASA, ESA, ESO and D. Coe (STScI)/J. Merten (Heidelberg/Bologna) couldn't see?

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Re: ALMA: Ancient Stardust Sheds Light on the First Stars

Post by Chris Peterson » Thu Mar 09, 2017 12:04 am

Ann wrote:But I can see nothing in the non-enlarged box at upper left. Are we supposed to see something in there? Or did it take computers and ALMA to tease out what even NASA, ESA, ESO and D. Coe (STScI)/J. Merten (Heidelberg/Bologna) couldn't see?
Even in this JPEG, I can make out a bit of what we see in the enlarged box if I really blow up the intensity at the low end. Doing that ruins the rest of the image, however, which is one reason the region of interest is separated and processed separately.
eso1708b2.jpg
eso1708b2.jpg (15.9 KiB) Viewed 211 times
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Re: ALMA: Ancient Stardust Sheds Light on the First Stars

Post by Ann » Thu Mar 09, 2017 2:32 am

Chris Peterson wrote:
Ann wrote:But I can see nothing in the non-enlarged box at upper left. Are we supposed to see something in there? Or did it take computers and ALMA to tease out what even NASA, ESA, ESO and D. Coe (STScI)/J. Merten (Heidelberg/Bologna) couldn't see?
Even in this JPEG, I can make out a bit of what we see in the enlarged box if I really blow up the intensity at the low end. Doing that ruins the rest of the image, however, which is one reason the region of interest is separated and processed separately.

eso1708b2.jpg
Thanks, Chris.

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