Featured Research

from universities, journals, and other organizations

Cornell Astronomers Use Arecibo Observatory To Reveal Radio Beacons, Called OH Megamasers, That Yield Galactic Clues

Date:
June 27, 2001
Source:
Cornell University
Summary:
When galaxies collide, they leave clues in the wake of their primordial history: radio beacons from their tell-tale hearts. Thanks to an upgrade of the radio telescope at Arecibo Observatory in Puerto Rico, these radio beacons -- 50 peculiar extragalactic objects called OH megamasers -- have been revealed.

PASADENA, Calif. -- When galaxies collide, they leave clues in the wake of their primordial history: radio beacons from their tell-tale hearts.

Related Articles


Thanks to an upgrade of the radio telescope at Arecibo Observatory in Puerto Rico, these radio beacons -- 50 peculiar extragalactic objects called OH megamasers -- have been revealed. Astronomers from Cornell University in Ithaca, N.Y., said today (June 5) at the national meeting of the American Astronomical Society (AAS) that these newly discovered OH (oxygen-hydrogen) megamasers could yield major clues in understanding the physics behind the formation of galaxies.

When galaxies collide, they send out a strong radio signal that can now be picked up by Arecibo, the world's most sensitive radio telescope, says Jeremy Darling, a Cornell doctoral student in astronomy. In that process there is a strong amplification of radio waves in the frigid interstellar clouds close to the galactic centers, which is known to astronomers as microwave amplification of stimulated emission of radiation, or maser. (While light is amplified in a laser, it is radio or microwave radiation that is amplified in a maser.)

Astronomical masers were first observed in 1965 in our galaxy, the Milky Way, where they are associated with stars shrouded in molecular gas. In colliding galaxies, astronomical masers can be a million times stronger than regular masers, thus earning them the name megamasers. The first known megamaser was discovered in 1982 by Willem Baan, then a staff scientist at the Arecibo Observatory.

OH megamaser radiation comes from compact clouds rich in oxygen and hydrogen that orbit galactic nuclei, bound by the nuclei's strong gravitational fields. The collision of two galaxies and the merger of their nuclei lead to a high compression of the gas, a star formation rate increase and an environment that favors the maser process, Darling says. The megamasers observed at Arecibo shine of frequencies around 1600 megahertz.

Astronomers can use the OH megamaser detection rate to measure the frequency of galaxy mergers throughout the history of the universe, Darling says. "The luminous -- in radio terms -- megamasers allow us to witness the merging process at work."

Arecibo Observatory, where the survey of distant galaxies and megamasers was carried out, is a national center managed and operated by Cornell for the National Science Foundation. In 1997, an extensive upgrade, which added a Gregorian reflector to Arecibo, was completed, increasing the telescope's sensitivity and radio spectrum coverage. This made it possible to search for extragalactic megamasers that were undetectable before the upgrade, says Darling.

One limiting factor in future developments of this research will be the deteriorating electromagnetic environment, Darling says. Relatively nearby OH megamasers are observable at frequencies close to 1600 megahertz. The detection of OH megamasers will require observations in parts of the electromagnetic spectrum that are increasingly obscured by interference from man-made radio sources.

Riccardo Giovanelli, Cornell professor of astronomy who is Darling's academic adviser and the co-author of the AAS paper, says: "The electromagnetic spectrum is our window to the cosmos, and human activity is cluttering it with the cacophony of our own sounds. It's as if we rented a room with a lovely view and proceeded to block the window with heavy drapes and inward-facing mirrors."

Darling and Giovanelli's AAS paper is titled "OH Megamasers: Luminous Radio Beacons of Merging Galaxies."


Story Source:

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


Cite This Page:

Cornell University. "Cornell Astronomers Use Arecibo Observatory To Reveal Radio Beacons, Called OH Megamasers, That Yield Galactic Clues." ScienceDaily. ScienceDaily, 27 June 2001. <www.sciencedaily.com/releases/2001/06/010606073336.htm>.
Cornell University. (2001, June 27). Cornell Astronomers Use Arecibo Observatory To Reveal Radio Beacons, Called OH Megamasers, That Yield Galactic Clues. ScienceDaily. Retrieved October 30, 2014 from www.sciencedaily.com/releases/2001/06/010606073336.htm
Cornell University. "Cornell Astronomers Use Arecibo Observatory To Reveal Radio Beacons, Called OH Megamasers, That Yield Galactic Clues." ScienceDaily. www.sciencedaily.com/releases/2001/06/010606073336.htm (accessed October 30, 2014).

Share This



More Space & Time News

Thursday, October 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Antares Liftoff Explosion

Raw: Antares Liftoff Explosion

AP (Oct. 29, 2014) Observers near Wallops Island recorded what they thought would be a routine rocket launch Tuesday night. What they recorded was a major rocket explosion shortly after lift off. (Oct 29) Video provided by AP
Powered by NewsLook.com
Raw: Russian Cargo Ship Docks at Space Station

Raw: Russian Cargo Ship Docks at Space Station

AP (Oct. 29, 2014) Just hours after an American cargo run to the International Space Station ended in flames, a Russian supply ship has arrived at the station with a load of fresh supplies. (Oct. 29) Video provided by AP
Powered by NewsLook.com
Journalist Captures Moment of Antares Rocket Explosion

Journalist Captures Moment of Antares Rocket Explosion

Reuters - US Online Video (Oct. 29, 2014) A space education journalist is among those who witness and record the explosion of an unmanned Antares rocket seconds after its launch. Rough Cut (no reporter narration) Video provided by Reuters
Powered by NewsLook.com
Rocket Explosion Under Investigation

Rocket Explosion Under Investigation

AP (Oct. 28, 2014) NASA and Orbital Sciences officials say they are investigating the explosion of an unmanned commercial supply rocket bound for the International Space Station. It blew up moments after liftoff Tuesday evening over the launch site in Virginia. (Oct. 28) 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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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