Subscribe free to our newsletters via your
. 24/7 Space News .




STELLAR CHEMISTRY
Scientists at Keck Discover the Fluffiest Galaxies
by Staff Writers
Maunakea HI (SPX) May 18, 2015


An ultra-diffuse galaxy, Dragonfly 17, is shown next to other types of galaxies, to scale. The Andromeda galaxy is a giant spiral like our own Milky Way, and a dwarf elliptical galaxy, NGC 205, is also shown. Ultra-diffuse galaxies have the same number of stars as dwarf ellipticals, but spread out over a much larger region. Image courtesy B. Schoening, V. Harvey/Reu Program/NOAO/AURA/NSF, P. Van Dokkum/Hubble Space Telescope. For a larger version of this image please go here.

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.

"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).

"If there are any aliens living on a planet in an ultra-diffuse galaxy, they would have no band of light across the sky, like our own Milky Way, to tell them they were living in a galaxy. The night sky would be much emptier of stars," said team member Aaron Romanowsky, of San Jose State University.

The UDGs were found in an area of the sky called the Coma cluster, where thousands of galaxies have been drawn together in a mutual gravitational dance. "Our fluffy objects add to the great diversity of galaxies that were previously known, from giant ellipticals that outshine the Milky Way, to ultra compact dwarfs," said University of California, Santa Cruz Professor Jean Brodie.

"The big challenge now is to figure out where these mysterious objects came from," said Roberto Abraham, of the University of Toronto. "Are they 'failed galaxies' that started off well and then ran out of gas? Were they once normal galaxies that got knocked around so much inside the Coma cluster that they puffed up? Or are they bits of galaxies that were pulled off and then got lost in space?"

The key next step in understanding UDGs is to to pin down exactly how much dark matter they have. Making this measurement will be even more challenging than the latest work.

The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes near the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and world-leading laser guide star adaptive optics systems.

The Low Resolution Imaging Spectrometer (LRIS) is a very versatile visible-wavelength imaging and spectroscopy instrument commissioned in 1993 and operating at the Cassegrain focus of Keck I. Since it has been commissioned it has seen two major upgrades to further enhance its capabilities: addition of a second, blue arm optimized for shorter wavelengths of light; and the installation of detectors that are much more sensitive at the longest (red) wavelengths.

Each arm is optimized for the wavelengths it covers. This large range of wavelength coverage, combined with the instrument's high sensitivity, allows the study of everything from comets (which have interesting features in the ultraviolet part of the spectrum), to the blue light from star formation, to the red light of very distant objects.

LRIS also records the spectra of up to 50 objects simultaneously, especially useful for studies of clusters of galaxies in the most distant reaches, and earliest times, of the universe.


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
W. M. Keck Observatory
Stellar Chemistry, The Universe And All Within It






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle








STELLAR CHEMISTRY
Water was plentiful in the early universe
Tel Aviv, Israel (SPX) May 18, 2015
Astronomers have long held that water - two hydrogen atoms and an oxygen atom - was a relative latecomer to the universe. They believed that any element heavier than helium had to have been formed in the cores of stars and not by the Big Bang itself. Since the earliest stars would have taken some time to form, mature, and die, it was presumed that it took billions of years for oxygen atoms to di ... read more


STELLAR CHEMISTRY
NASA's LRO Moves Closer to the Lunar Surface

European Space Agency Director Wants to Set Up a Moon Base

Russia Invites China to Join in Creating Lunar Station

Japan to land first unmanned spacecraft on moon in 2018

STELLAR CHEMISTRY
Exploring the 'Spirit of St. Louis' Crater

The First Martian Marathon

Technique for finding signs of life on the Red Planet

Quick Detour by NASA Mars Rover Checks Ancient Valley

STELLAR CHEMISTRY
NASA Challenges Designers to Construct Habitat for Deep Space Exploration

The Moon or Mars: Flawed Debate, False Choice - Part One

Young Innovators Bring Creations to Life in NASA Goddard Spinoff Challenge

Photonic Laser Thruster Propels Simulated Spacecraft

STELLAR CHEMISTRY
3D printer making Chinese space suit parts

Xinhua Insight: How China joins space club?

Chinese scientists mull power station in space

China completes second test on new carrier rocket's power system

STELLAR CHEMISTRY
ISS Partners Adjust Spacecraft Schedule

Samantha's longer stay on ISS

Italian astronaut shows how to use restroom on ISS online

Russia delays return of ISS crew members after supply ship failure

STELLAR CHEMISTRY
Commission on Proton Rocket Failure to Finish Investigation by End of May

DirecTV-15 and SKY Mexico-1 integrated for Ariane 5 heavy-lift mission

Russia to Launch US Comms Satellite Into Space

Report: SpaceX Falcon 9 rocket certified to fly NASA missions

STELLAR CHEMISTRY
Weather forecasts for planets beyond our solar system

Astrophysicists offer proof that famous image shows forming planets

Astronomers detect drastic atmospheric change in super Earth

New exoplanet too big for its star

STELLAR CHEMISTRY
Light it up: Materials crystallize with surprising properties

ISRO to launch first indigenous multi-object tracking radar in next 3 months

India to test its home-made multi-object tracking radar next month

The Internet wants a laser mounted on the space station




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.