Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Green Pea galaxies could help astronomers understand early universe

04.04.2013
The rare Green Pea galaxies discovered by the general public in 2007 could help confirm astronomers' understanding of reionization, a pivotal stage in the evolution of the early universe, say University of Michigan researchers.
Reionization occurred a few hundred million years after the Big Bang as the first stars were turning on and forming the first galaxies. During this period, the space between the galaxies changed from an opaque, neutral fog to a transparent charged plasma, as it is today. Plasma is gas that's electrically charged.

As for how this happened, the prevailing theory holds that massive stars in the early galaxies produced an abundance of high-energy ultraviolet light that escaped into intergalactic space. There, the UV light interacted with the neutral hydrogen gas it met, blasting electrons off the hydrogen atoms and leaving behind a plasma of negatively charged electrons and positively charged hydrogen ions.

"We think this is what happened but when we looked at galaxies nearby, the high-energy radiation doesn't appear to make it out. There's been a push to find some galaxies that show signs of radiation escaping," said Anne Jaskot, a doctoral student in astronomy.

Jaskot and Sally Oey, an associate professor of astronomy in the College of Literature, Science, and the Arts, have found that the Green Peas could hold that evidence. Their findings are published in the current edition of the Astrophysical Journal.

"The Green Peas are compact, highly star-forming galaxies that are very similar to the early galaxies in the universe," Jaskot said. "Our analysis shows they may be leaking ionizing radiation."

The researchers focused on six of the most intensely star-forming Green Pea galaxies, which are between one billion and five billion light years away. They studied their emission lines as observed by the Sloan Digital Sky Survey. Emission lines show how light interacts with matter, and in this case, they helped the astronomers understand the relationship between the stars and gas in these galaxies.

The emission lines told Jaskot and Oey how much light the galaxies absorbed. Then, to determine how much light was there to start with, they ran models to estimate, for example, how old the galaxies are and how many stars they contain. The galaxies, the researchers determined, produced more radiation than the researchers detected, so they infer that some of it must have escaped.

"An analogy might be if you have a tablecloth and you spill something on it. If you see the cloth has been stained all the way to the edges, there's a good chance it also spilled onto the floor," Jaskot said. "We're looking at the gas like the tablecloth and seeing how much light it has absorbed. It has absorbed a lot of light. We're seeing that the galaxy is saturated with it and there's probably some extra that spilled off the edges."

Jaskot says the Green Peas are exciting candidates to help astronomers understand a major milestone in the development of the cosmos 13 billion years ago.

The paper is called "The Origin and Optical Depth of Ionizing Radiation in the 'Green Pea' Galaxies. The research is funded by the National Science Foundation.

Nicole Casal Moore | EurekAlert!
Further information:
http://www.umich.edu

More articles from Physics and Astronomy:

nachricht Tiny lasers from a gallery of whispers
20.09.2017 | American Institute of Physics

nachricht New quantum phenomena in graphene superlattices
19.09.2017 | Graphene Flagship

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>