W.M. Keck Observatory | 2015 May 14
An international team of researchers led by Pieter van Dokkum at Yale University have used the W. M. Keck Observatory to confirm the existence of the most diffuse class of galaxies known in the universe. These "fluffiest galaxies" are nearly as wide as our own Milky Way galaxy – about 60,000 light years – yet harbor only one percent as many stars. The findings were recently published in the Astrophysical Journal Letters.[attachment=0]UDG_PR_fig1.jpg[/attachment][hr][/hr]
“If the Milky Way is a sea of stars, then these newly discovered galaxies are like wisps of clouds”, said van Dokkum. “We are beginning to form some ideas about how they were born and it’s remarkable they have survived at all. They are found in a dense, violent region of space filled with dark matter and galaxies whizzing around, so we think they must be cloaked in their own invisible dark matter ‘shields’ that are protecting them from this intergalactic assault.”
The team made the latest discovery by combining results from one of the world's smallest telescopes as well as the largest telescope on Earth. The Dragonfly Telephoto Array used 14-centimeter state of the art telephoto lens cameras to produce digital images of the very faint, diffuse objects. Keck Observatory’s 10-meter Keck I telescope, with its Low Resolution Imaging Spectrograph, then separated the light of one of the objects into colors that diagnose its composition and distance.
Finding the distance was the clinching evidence. The data from Keck Observatory showed the diffuse "blobs" are very large and very far away, about 300 million light years, rather than small and close by. The blobs can now safely be called Ultra Diffuse Galaxies (UDGs). ...
Spectroscopic Confirmation of the Existence of Large, Diffuse Galaxies in the Coma Cluster - Pieter van Dokkum et al
- Astrophysical Journal Letters 804(1) L26 (01 May 2015) DOI: 10.1088/2041-8205/804/1/L26
arXiv.org > astro-ph > arXiv:1504.03320 > 13 Apr 2015
- Astrophysical Journal Letters 798(2) L45 (10 Jan 2015) DOI: 10.1088/2041-8205/798/2/L45
arXiv.org > astro-ph > arXiv:1410.8141 > 29 Oct 2014 (v1), 09 Jan 2015 (v2)
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