Featured Research

from universities, journals, and other organizations

Census of the invisible universe reveals extraordinary high star-formation rates across history of the universe

Date:
December 4, 2012
Source:
European Space Agency (ESA)
Summary:
By combining the observing powers of ESA’s Herschel space observatory and the ground-based Keck telescopes, astronomers have characterized hundreds of previously unseen starburst galaxies, revealing extraordinary high star-formation rates across the history of the Universe. Starburst galaxies give birth to hundreds of solar masses’ worth of stars each year in short-lived but intense events.

Starburst galaxies across the Universe.
Credit: ESA

By combining the observing powers of ESA's Herschel space observatory and the ground-based Keck telescopes, astronomers have characterised hundreds of previously unseen starburst galaxies, revealing extraordinary high star-formation rates across the history of the Universe.

Starburst galaxies give birth to hundreds of solar masses' worth of stars each year in short-lived but intense events.

By comparison, our own Milky Way Galaxy on average produces the equivalent of only one Sun-like star per year.

Starburst galaxies generate so much starlight that they should outshine our Galaxy hundreds to thousands of times over, but the enormous quantities of gas fuelling them also contain vast amounts of dust as a result of the frantic star formation.

The dust absorbs much of the visible light, meaning that many of them look quite insignificant in that part of the spectrum.

However, the dust is warmed by the surrounding hot stars and re-emits the energy at far-infrared wavelengths.

Using ESA's infrared Herschel space observatory, astronomers measured the temperature and brightness of thousands of dusty galaxies. From these, their star-formation rate could be then calculated.

"Starburst galaxies are the brightest galaxies in the Universe and contribute significantly to cosmic star formation, so it's important to study them in detail and understand their properties," says Dr Caitlin Casey of the University of Hawai'i, lead author of the papers discussing the results in the Astrophysical Journal.

"Some of the galaxies found in this new survey have star-formation rates equivalent to the birth of several thousand solar-mass stars per year, constituting some of the brightest infrared galaxies yet discovered."

To provide context to the observations and understand how star formation has changed over the Universe's 13.7 billion year history, the distances to the galaxies were also needed.

With Herschel signposting the way, Dr Casey's team used spectrometers on the twin 10-metre W.M. Keck telescopes on Mauna Kea, Hawai'i, and obtained the redshifts of 767 of the starburst galaxies.

Redshifts provide astronomers with a measure of how long the light from each galaxy has travelled across the Universe, which, in turn, indicates when in cosmic history the light from each galaxy was emitted.

For most of the galaxies it was found that the light has been travelling towards us for 10 billion years or less.

About 5% of the galaxies are at even greater redshifts: their light was emitted when the Universe was only 1-3 billion years old.

"The Herschel data tell us how fiercely and prolifically these galaxies are producing stars," says Seb Oliver from University of Sussex, UK, and Principal Investigator for the HerMES Key Programme, within which the data have been collected.

"Combining this information with the distances provided by the Keck data, we can uncover the contribution of the starburst galaxies to the total amount of stars produced across the history of the Universe."

How such large numbers of starburst galaxies formed during the first few billions of years of the Universe's existence poses a vital problem for galaxy formation and evolution studies.

One leading theory proposes that a collision between two young galaxies could have sparked an intense short-lived phase of star formation.

Another theory speculates that, when the Universe was young, individual galaxies had much more gas available to them to feed from, enabling higher rates of star formation without the need of collisions.

"It's a hotly debated topic that requires details on the shape and rotation of the galaxies before it can be resolved," adds Dr Casey.

"Before Herschel, the largest similar survey of distant starbursts involved only 73 galaxies -- we've improved on that by over a factor of ten in this combined survey with Keck to determine the characteristics of this important galaxy population," adds Göran Pilbratt, ESA's Herschel project scientist.


Story Source:

The above story is based on materials provided by European Space Agency (ESA). Note: Materials may be edited for content and length.


Journal References:

  1. C. M. Casey, S. Berta, M. Béthermin, J. Bock, C. Bridge, D. Burgarella, E. Chapin, S. C. Chapman, D. L. Clements, A. Conley, C. J. Conselice, A. Cooray, D. Farrah, E. Hatziminaoglou, R. J. Ivison, E. Le Floc'h, D. Lutz, G. Magdis, B. Magnelli, S. J. Oliver, M. J. Page, F. Pozzi, D. Rigopoulou, L. Riguccini, I. G. Roseboom, D. B. Sanders, D. Scott, N. Seymour, I. Valtchanov, J. D. Vieira, M. Viero, J. Wardlow. A Population of z>2 Far-Infrared Herschel-SPIRE selected Starbursts. Astrophysical Journal, 2012
  2. C. M. Casey, S. Berta, M. Béthermin, J. Bock, C. Bridge, J. Budynkiewicz, D. Burgarella, E. Chapin, S. C. Chapman, D. L. Clements, A. Conley, C. J. Conselice, A. Cooray, D. Farrah, E. Hatziminaoglou, R. J. Ivison, E. Le Floc'h, D. Lutz, G. Magdis, B. Magnelli, S. J. Oliver, M. J. Page, F. Pozzi, D. Rigopoulou, L. Riguccini, I. G. Roseboom, D. B. Sanders, D. Scott, N. Seymour, I. Valtchanov, J. D. Vieira, M. Viero, J. Wardlow. A Redshift Survey of Herschel Far-Infrared Selected Starbursts and Implications for Obscured Star Formation. Astrophysical Journal, 2012

Cite This Page:

European Space Agency (ESA). "Census of the invisible universe reveals extraordinary high star-formation rates across history of the universe." ScienceDaily. ScienceDaily, 4 December 2012. <www.sciencedaily.com/releases/2012/12/121204112018.htm>.
European Space Agency (ESA). (2012, December 4). Census of the invisible universe reveals extraordinary high star-formation rates across history of the universe. ScienceDaily. Retrieved April 18, 2014 from www.sciencedaily.com/releases/2012/12/121204112018.htm
European Space Agency (ESA). "Census of the invisible universe reveals extraordinary high star-formation rates across history of the universe." ScienceDaily. www.sciencedaily.com/releases/2012/12/121204112018.htm (accessed April 18, 2014).

Share This



More Space & Time News

Friday, April 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Baby Moon 'Peggy' Spotted In Saturn's Rings

New Baby Moon 'Peggy' Spotted In Saturn's Rings

Newsy (Apr. 15, 2014) — A bump in the rings could be a half-mile-wide miniature moon. It was found by accident in Cassini probe images. Video provided by Newsy
Powered by NewsLook.com
Americas Glimpse Total Lunar Eclipse

Americas Glimpse Total Lunar Eclipse

AFP (Apr. 15, 2014) — A total lunar eclipse, the first since December 2011, took place early Tuesday morning with the Americas getting the best glimpse. Duration: 1:19 Video provided by AFP
Powered by NewsLook.com
NASA Showcases Lunar Eclipse

NASA Showcases Lunar Eclipse

AP (Apr. 15, 2014) — Star gazers in parts of North and South America got a rare treat early Tuesday morning - a total eclipse of the moon. (April 15) Video provided by AP
Powered by NewsLook.com
Spacecrafts Could Use Urine As Fuel Source

Spacecrafts Could Use Urine As Fuel Source

Newsy (Apr. 15, 2014) — New research says the urea from urine could be recycled for fuel. Urea is filtered out of wastewater when making drinking water. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins