Hubble Uncovers Largest Known Population of Star Clusters

Find out the latest thinking about our universe.
User avatar
bystander
Apathetic Retiree
Posts: 21587
Joined: Mon Aug 28, 2006 2:06 pm
Location: Oklahoma

Hubble Uncovers Largest Known Population of Star Clusters

Post by bystander » Thu Sep 12, 2013 8:34 pm

Hubble Uncovers Largest Known Population of Star Clusters
NASA | STScI | HubbleSite | 2013 Sep 12
NASA's Hubble Space Telescope has uncovered the largest known population of globular star clusters, an estimated 160,000, swarming like bees inside the crowded core of the giant grouping of galaxies Abell 1689. By comparison, our Milky Way galaxy hosts about 150 such clusters.

Studying globular clusters is critical to understanding the early, intense star-forming episodes that marked galaxy formation. The Hubble observations also confirm that these compact stellar groupings can be used as reliable tracers of the amount of dark matter locked away in immense galaxy clusters.

Globular clusters, dense bunches of hundreds of thousands of stars, are the homesteaders of galaxies, containing some of the oldest surviving stars in the universe. Almost 95 percent of globular cluster formation occurred within the first 1 billion or 2 billion years after our universe was born in the big bang 13.8 billion years ago.

A team of astronomers, led by John Blakeslee of the NRC Herzberg Astrophysics Program at the Dominion Astrophysical Observatory in Victoria, B.C., used Hubble's sensitivity and sharpness to discover a bounty of these stellar fossils, which is roughly twice as large as any other population found in previous globular cluster surveys. The Hubble observations also win the distance record for the farthest such systems ever studied, at 2.25 billion light-years away.

The research team found that the globular clusters are intimately intertwined with dark matter. "In our study of Abell 1689, we show how the relationship between globular clusters and dark matter depends on the distance from the galaxy cluster's center," explained team member Karla Alamo-Martinez of the Center for Radio Astronomy and Astrophysics of the National Autonomous University of Mexico in Morelia. "In other words, if you know how many globular clusters are within a certain distance, we can give you an estimate of the amount of dark matter."

Alamo-Martinez is also the lead author on the team's science paper describing the results. The paper appears in the Sept. 20 issue of The Astrophysical Journal.

Although dark matter is invisible, it is considered the underlying gravitational scaffolding upon which stars and galaxies are built. Understanding dark matter can yield clues on how large structures such as galaxies and galaxy clusters were assembled billions of years ago.

The Hubble study shows that most of the globular clusters in Abell 1689 formed near the center of the galaxy cluster, which contains a deep well of dark matter. Their number decreases the farther away Hubble looked from the core, corresponding with a comparable drop in the amount of dark matter.

"The globular clusters are fossils of the earliest star formation in Abell 1689, and our work shows they were very efficient in forming in the denser regions of dark matter near the center of the galaxy cluster," Blakeslee said. "Our findings are consistent with studies of globular clusters in other galaxy clusters, but extend our knowledge to regions of higher dark matter density."

The astronomers used Hubble's Advanced Camera for Surveys to peer deep inside the heart of Abell 1689, detecting the visible-light glow of 10,000 globular clusters, some as dim as 29th magnitude. Based on that number, Blakeslee's team estimated that more than 160,000 globular clusters are huddled within a diameter of 2.4 million light-years. "Even though we are looking deep into the cluster, we're only seeing the brightest globular clusters, and only near the center of Abell 1689 where Hubble was pointed," he said.

The brightness of most of the globular clusters is estimated to be 31st magnitude. This is out of reach for Hubble, but not for NASA's James Webb Space Telescope, an infrared observatory scheduled to launch later this decade. By going fainter, Webb should be able to see many more of the globular clusters.

Blakeslee's quest to use Hubble to conduct a globular cluster census in Abell 1689 began 10 years ago after astronauts added the Advanced Camera for Surveys to Hubble's arsenal of science instruments. While analyzing some gravitational lensing data of Abell 1689 obtained with the newly installed camera, Blakeslee spotted dots of light peppered throughout the images. The dots turned out to be the brightest members of a teeming population of globular clusters.

Galaxy Cluster Abell 1689
NASA | ESA | STScI | AURA | Hubble Heritage | 2013 Sep 12

New Hubble image of galaxy cluster Abell 1689
ESA/HEIC Hubble Photo Release 2013 Sep 12

The Rich Globular Cluster System of Abell 1689 and the Radial Dependence
of the Globular Cluster Formation Efficiency
- K. A. Alamo-Martínez et al
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: Hubble Uncovers Largest Known Population of Star Cluster

Post by neufer » Fri Sep 13, 2013 3:02 am

Art Neuendorffer

User avatar
Beyond
500 Gigaderps
Posts: 6889
Joined: Tue Aug 04, 2009 11:09 am
Location: BEYONDER LAND

Re: Hubble Uncovers Largest Known Population of Star Cluster

Post by Beyond » Fri Sep 13, 2013 4:38 am

I used to be able to eat globs of those clusters. :chomp: :yes: It's now been years since I've had any at all.
To find the Truth, you must go Beyond.

BillBixby
Science Officer
Posts: 146
Joined: Tue Jul 10, 2012 6:57 pm

Re: Hubble Uncovers Largest Known Population of Star Cluster

Post by BillBixby » Tue Sep 17, 2013 6:21 pm

Peanut Clusters - you know that peanuts are in there, but you can't see them or get individual info on any given peanut due to the dark matter surrounding them.

The obvious conclusion is that the unknown dark matter of space is actually chocolate. :P This conclusion should speed the investigation of dark matter and lead to industry developing commercial mining and finding less expensive methods to launch and recover space vehicles. :D

User avatar
Beyond
500 Gigaderps
Posts: 6889
Joined: Tue Aug 04, 2009 11:09 am
Location: BEYONDER LAND

Re: Hubble Uncovers Largest Known Population of Star Cluster

Post by Beyond » Tue Sep 17, 2013 6:34 pm

BillBixby wrote:The obvious conclusion is that the unknown dark matter of space is actually chocolate.
But what kind of chocolate :?: Milk, Special Dark, Belgium, ETC. Powdered, liquid or solid :?: :?:
To find the Truth, you must go Beyond.

User avatar
bystander
Apathetic Retiree
Posts: 21587
Joined: Mon Aug 28, 2006 2:06 pm
Location: Oklahoma

Re: Hubble Uncovers Largest Known Population of Star Cluster

Post by bystander » Tue Sep 17, 2013 6:43 pm

Beyond wrote:But what kind of chocolate :?:
Dark chocolate, of course. :roll:
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

User avatar
Beyond
500 Gigaderps
Posts: 6889
Joined: Tue Aug 04, 2009 11:09 am
Location: BEYONDER LAND

Re: Hubble Uncovers Largest Known Population of Star Cluster

Post by Beyond » Tue Sep 17, 2013 6:49 pm

bystander wrote:
Beyond wrote:But what kind of chocolate :?:
Dark chocolate, of course. :roll:
That's no help, lottsa chocolate is "Dark", except of course, for white chocolate. :chomp:
To find the Truth, you must go Beyond.

BillBixby
Science Officer
Posts: 146
Joined: Tue Jul 10, 2012 6:57 pm

Re: Hubble Uncovers Largest Known Population of Star Cluster

Post by BillBixby » Tue Sep 17, 2013 6:54 pm

I see you agree we must investigate.

User avatar
bystander
Apathetic Retiree
Posts: 21587
Joined: Mon Aug 28, 2006 2:06 pm
Location: Oklahoma

Re: Hubble Uncovers Largest Known Population of Star Cluster

Post by bystander » Tue Sep 17, 2013 7:14 pm

Beyond wrote:That's no help, lottsa chocolate is "Dark", except of course, for white chocolate. :chomp:
Dark chocolate, as apposed to white or milk chocolate, contains no dairy products, and usually less sugar.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

User avatar
BMAONE23
Commentator Model 1.23
Posts: 4076
Joined: Wed Feb 23, 2005 6:55 pm
Location: California

Re: Hubble Uncovers Largest Known Population of Star Cluster

Post by BMAONE23 » Tue Sep 17, 2013 7:21 pm

No need to investigate
Here's the proof
Image
courtesy Americansweets.co.uk

User avatar
Beyond
500 Gigaderps
Posts: 6889
Joined: Tue Aug 04, 2009 11:09 am
Location: BEYONDER LAND

Re: Hubble Uncovers Largest Known Population of Star Cluster

Post by Beyond » Tue Sep 17, 2013 8:38 pm

ha-ha, good try, BMAONE23, but investigation is still needed, as the 'proof', in that current state, remains darkly wrapped.
To find the Truth, you must go Beyond.

User avatar
BMAONE23
Commentator Model 1.23
Posts: 4076
Joined: Wed Feb 23, 2005 6:55 pm
Location: California

Re: Hubble Uncovers Largest Known Population of Star Cluster

Post by BMAONE23 » Tue Sep 17, 2013 9:03 pm

That's the Stasis Pod's containment field