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 Further Improvement of Qubit Lifetime for Quantum Computers
09.12.2016 | Forschungszentrum Jülich

nachricht Electron highway inside crystal
09.12.2016 | Julius-Maximilians-Universität Würzburg

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: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>