Featured Research

from universities, journals, and other organizations

Stellar Birth Control In The Early Universe

Date:
October 2, 2006
Source:
Yale University
Summary:
An international team of astronomers based at Yale and Leiden University in The Netherlands found that "old stars" dominated many large galaxies in the early universe, raising the new question of why these galaxies progressed into "adulthood" so early in the life of the universe. Their results imply that the galaxies have a method of "birth control" that is very effective.

Extremely massive black holes in the centers of galaxies may serve as 'cosmic contraceptives' in the early Universe, suppressing the birth of new stars. The blue beam of light in this Hubble Space Telescope image of the nearby galaxy M87 emanates from a black hole which has a mass exceeding a billion times that of the Sun.
Credit: NASA and the Hubble Heritage Team (STScI/AURA)

An international team of astronomers based at Yale and Leiden University in The Netherlands found that "old stars" dominated many large galaxies in the early universe, raising the new question of why these galaxies progressed into "adulthood" so early in the life of the universe.

Every year only a handful of new stars are born out of the gas that fills the space between the stars in galaxies like the Milky Way. To account for the large number of stars in the Universe today, about 400 billion in the Milky Way alone, it was thought that the "stellar birth rate" must have been much higher in the past.

Surprisingly, in this study appearing in the October 2 issue of Astrophysical Journal, astronomers using the 8.1m Gemini telescope in Chile report that many of the largest galaxies in the Universe had a very low stellar birth rate even when the Universe was only about 20 percent of its present age.

"Our new results imply that the stars in many large galaxies were born when the Universe was in its infancy, in the first few billion years after the Big Bang," said team leader Mariska Kriek, a PhD student from Leiden University and Yale. "The results confirm what some astronomers had suspected -- galaxies seem to have some method of 'birth control' that is very effective."

These new findings add to growing evidence that in big galaxies the formation of new stars was significantly suppressed after an initial period of vigorous activity. "These galaxies had a very violent early youth, but rose into stable adulthood well before many galaxies like the Milky Way were even in kindergarten," said Kriek."

The astronomers used the uniquely powerful Gemini Near Infrared Spectrograph, to analyze the light of distant galaxies simultaneously over many different wavelengths. They studied 20 galaxies so distant that their light had been traveling for nearly 11 billion years, or 80 percent of the age of the Universe.

"The unexpected finding is what was not found -- we expected to see a prominent signal from ionized Hydrogen, the tell-tale signature of star birth. Remarkably, for nine of the twenty galaxies that we observed, this signature is not seen at all," said Pieter van Dokkum, associate professor of astronomy and physics at Yale University. "It gives a firm limit on the stellar birth rate in these objects."

One suggestion is that enormous black holes in the centers of large galaxies may be responsible for suppressing star formation. When material spirals into a black hole, huge amounts of energy are released and are rapidly injected into the galaxy's gas. This energy injection may dilute the gas sufficiently to prevent future star birth.

"Evidence for the presence of these black holes is seen in several of the galaxies studied, lending support to the idea that black holes serve as cosmic contraceptives in the young Universe," said van Dokkum.

The research was funded by the Netherlands Foundation for Research, the Leids Kerkhoven-Bosscha Fonds, the National Science Foundation, and NASA. Other authors on the paper were Ryan Quadri, Eric Gawiser, David Herrera, Danilo Marchesini and C. Megan Urry from Yale; Marijn Franx, Edward N. Taylor and Stijn Wuyts from Leiden; Garth D. Illingworth, University of California, Santa Cruz; Ivo Labbe, Carnegie Observatories, Pasadena, CA; Paulina Lira, Universidad de Chile; Hans-Walter Rix, Max-Planck-Institute fur Astronomie; Gregory Rudnick, National Optical Astronomy Observatory, Tucson, AZ and Sune Toft, European Southern Observatory, Munchen, Germany.

Citation: Astrophysical Journal: (October 1, 2006).


Story Source:

The above story is based on materials provided by Yale University. Note: Materials may be edited for content and length.


Cite This Page:

Yale University. "Stellar Birth Control In The Early Universe." ScienceDaily. ScienceDaily, 2 October 2006. <www.sciencedaily.com/releases/2006/10/061001204443.htm>.
Yale University. (2006, October 2). Stellar Birth Control In The Early Universe. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2006/10/061001204443.htm
Yale University. "Stellar Birth Control In The Early Universe." ScienceDaily. www.sciencedaily.com/releases/2006/10/061001204443.htm (accessed July 25, 2014).

Share This




More Space & Time News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

This Week @ NASA, July 25, 2014

This Week @ NASA, July 25, 2014

NASA (July 25, 2014) Apollo 11 celebration, Next Giant Leap anticipation, ISS astronauts appear in the House and more... Video provided by NASA
Powered by NewsLook.com
Space to Ground: Coming and Going

Space to Ground: Coming and Going

NASA (July 25, 2014) One station cargo ship leaves, another arrives, aquatic research and commercial spinoffs. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
Powered by NewsLook.com
How A Solar Flare Could Have Wrecked Earth's Electronics

How A Solar Flare Could Have Wrecked Earth's Electronics

Newsy (July 25, 2014) Researchers say if Earth had been a week earlier in its orbit around the sun, it would have taken a direct hit from a 2012 coronal mass ejection. Video provided by Newsy
Powered by NewsLook.com
Raw: ISS Cargo Ship Launches in Kazakhstan

Raw: ISS Cargo Ship Launches in Kazakhstan

AP (July 23, 2014) The Progress 56 cargo ship launched from the Baikonur Cosmodrome in Kazakhstan Wednesday. NASA says it will deliver cargo and crew supplies to the International Space Station. (July 23) Video provided by AP
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