. 24/7 Space News .
Hubble Sees Star Birth Gone Wild

Hubble's Advanced Camera for Surveys spies more than 200 mammoth star clusters in the heart of galaxy Arp 220. Image credit: NASA/ESA/C. Wilson (McMaster University, Hamilton, Ontario)
by Staff Writers
Baltimore MD (SPX) Jun 16, 2006
Staring into the crowded, dusty core of two merging galaxies, NASA's Hubble Space Telescope has uncovered a region where star formation has gone wild. The interacting galaxies appear as a single, odd-looking galaxy called Arp 220. The galaxy is a nearby example of the aftermath of two colliding galaxies.

In fact, Arp 220 is the brightest of the three galactic mergers closest to Earth. This latest view of the galaxy is yielding new insights into the early universe, when galactic wrecks were more common.

Hubble's Advanced Camera for Surveys has unveiled more than 200 mammoth star clusters, far outnumbering the six spied by Hubble in a 1992 observation of Arp 220 taken by the Wide Field Planetary Camera, which did not have the sharpness of the Advanced Camera.

The heftiest Arp 220 cluster observed by Hubble contains enough material to equal about 10 million suns, which is twice as massive as any comparable star cluster in the Milky Way.

The clusters are so compact, however, that even at their moderate distance they look to Hubble like brilliant single stars. Astronomers know the clusters are not stars, because they are much brighter than a star would be at that distance, 250 million light-years away in the constellation Serpens, the snake.

The star birth frenzy is happening in a very small region, about 5,000 light-years across (about 5 percent of the Milky Way's diameter), where the gas and dust is very dense. There is as much gas in that tiny region as there is in the entire Milky Way.

"This is star birth in the extreme," said astronomer Christine D. Wilson of McMaster University in Hamilton, Ontario, and the leader of the study. "Our result implies that very high star-formation rates are required to form supermassive star clusters. This is a nearby look at a phenomenon that was common in the early universe, when many galaxies were merging."

Wilson's team obtained measurements of the masses and ages for 14 of the clusters, which allowed them to estimate the masses and ages for all the clusters more accurately. The observations revealed two populations of star clusters.

One population is less than 10-million years old; the second, 70-million to 500-million years old. Clusters in the younger group are more massive than those in the older group.

Wilson said she doesn't know whether the flurry of star birth occurred at two different epochs or at a continuous frantic pace and perhaps they are not seeing the intermediate-age population.

She does know that the starburst was fueled by a collision between two galaxies that began about 700-million years ago. The effects of the merger have stretched out over hundreds of millions of years.

The team's results, which appeared in the April 20 issue of the Astrophysical Journal, are based on new observations with Hubble's Advanced Camera for Surveys and on a previous study by the Near Infrared Camera and Multi-Object Spectrometer.

The Advanced Camera observations, taken in visible light in August 2002, revealed the large cluster population and produced ages for the older grouping of clusters. The near-infrared camera study snapped images of the younger cluster population.

Although the new Hubble image showcases Arp 220 in visible light, the galaxy shines brightest in infrared light. In fact, Arp 220 is called an ultra-luminous infrared galaxy.

ULIRGs are the products of mergers between galaxies, which can create firestorms of star birth. Starlight from the new stars heats the surrounding dust, causing the galaxies to glow brilliantly in infrared light.

Only a small amount of visible light escapes through the dust-enshrouded galaxy. If astronomers had an unobstructed view of Arp 220 in visible light, the galaxy would shine 50 times brighter than our Milky Way, because of the light from its massive clusters and associated star formation.

Arp 220 shares a kinship with other interacting galaxies, such as the well-known Antennae galaxies. Both are the products of galactic mergers.

The merging process in Arp 220, however, is farther along than in the Antennae. In fact, Wilson said, one cannot even see the two galaxies that combined to make up Arp 220. Radio data show two objects 1,000 light-years apart that may represent the cores of the original galaxies.

The galaxy will continue to manufacture star clusters until it exhausts all of its gas, which at the current rate will happen in about 40-million years. This may seem like a long time, but it is practically a blink of an eye for a process occurring on a galactic scale.

By then, Arp 220 will look like the elliptical galaxies seen today, which have little gas. Some of the giant clusters - those that are now 100-million years old - will still be there.

The galaxy is the 220th object in Halton Arp's Atlas of Peculiar Galaxies.

Related Links
Hubble images



Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


Triangulum Galaxy Shines In New Portrait
Cambridge MA (SPX) Jun 15, 2006
In this new image from the Multiple-Mirror Telescope Observatory's 6.5-meter telescope, the Triangulum galaxy reveals stunning swirls of stars and dust dotted with brilliant pink nebulae. The new photograph of the Triangulum galaxy showcases the dazzling capabilities of MMT's new Megacam instrument.







  • Douglass Urges NASA And Industry To Address Workforce Crisis
  • Stephen Hawking Calls For Mankind To Reach For Stars
  • Optimize Trade Study Analyses With Software From Phoenix Integration And AGI
  • NASA Ames Lays Out CEV Tasks

  • Teachers To Learn About Mars-Earth Science
  • Brits Unveil Latest Robot To Search For Life On Mars
  • British Scientists Unveil Latest Craft To Search For Life On Mars
  • Spirit Finds Possible Iron Meteorite

  • Sea Launch Begins Galaxy 16 Countdown
  • Preps Begin For Next Ariane Dual Satellite Launch
  • Sea Launch Awarded Assignment For Thuraya-3 Satellite
  • Sea Launch To Orbit Telecom Satellite June 17

  • Russia Launches New Remote Detection Satellite
  • Cloudsat Flexes Muscles With Alberto
  • Google Announces Major Update For Google Earth
  • Harmful Algal Blooms Monitored From Space In Chile

  • Three Trojan Asteroids Share Neptune Orbit
  • New Horizons Crosses The Asteroid Belt
  • Trio Of Neptunes And Their Belt
  • New Model Could Explain Eccentric Triton Orbit

  • Hubble Sees Star Birth Gone Wild
  • Triangulum Galaxy Shines In New Portrait
  • XMM-Newton Spots Greatest Ball Of Fire
  • Astronomers Find Ancient Cities Of Galaxies

  • NASA Spies Lunar Meteoroid Impact
  • Shanghai Lands Star Role In Satellite Mission
  • The Sky Is Falling
  • SMART-1 Captures Central Peaks Of Zucchius Crater

  • Atmel and u-blox Introduce High Sensitivity/Low Power Single-Chip GPS Receiver
  • European Space Parliamentarians Meet In Brussels
  • deCarta And Inrix Accelerate Traffic-Enabled Location-based Services
  • SiRF Teams With Fastrax To Speed GPS Deployments

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights 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 SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement