Featured Research

from universities, journals, and other organizations

Early universe 'warmed up' later than previously believed: Research suggests a way to detect the earliest black holes

Date:
February 5, 2014
Source:
American Friends of Tel Aviv University
Summary:
A new study reveals that black holes, formed from the first stars in our universe, heated the gas throughout space later than previously thought. They also imprinted a clear signature in radio waves which astronomers can now search for. The study is a major new finding about the origins of the universe.

New research suggests that black holes, formed from the first stars in our universe, heated the gas throughout space later than previously thought.
Credit: © procy_ab / Fotolia

A new study from Tel Aviv University reveals that black holes, formed from the first stars in our universe, heated the gas throughout space later than previously thought. They also imprinted a clear signature in radio waves which astronomers can now search for. The work is a major new finding about the origins of the universe.

"One of the exciting frontiers in astronomy is the era of the formation of the first stars," explains Prof. Rennan Barkana of TAU's School of Physics and Astronomy, an author of the study. "Since the universe was filled with hydrogen atoms at that time, the most promising method for observing the epoch of the first stars is by measuring the emission of hydrogen using radio waves."

The study, just published in the journal Nature, was co-authored by Dr. Anastasia Fialkov of TAU and the Ιcole Normale Supιrieure in Paris and Dr. Eli Visbal of Columbia and Harvard Universities.

Cosmic archaeology

Astronomers explore our distant past, billions of years back in time. Unlike Earth-bound archaeologists, however, who can only study remnants of the past, astronomers can see the past directly. The light from distant objects takes a long time to reach Earth, and astronomers can see these objects as they were back when that light was emitted. This means that if astronomers look out far enough, they can see the first stars as they actually were in the early universe. Thus, the new finding that cosmic heating occurred later than previously thought means that observers do not have to search as far, and it will be easier to see this cosmic milestone.

Cosmic heating may offer a way to directly investigate the earliest black holes, since it was likely driven by star systems called "black-hole binaries." These are pairs of stars in which the larger star ended its life with a supernova explosion that left a black-hole remnant in its place. Gas from the companion star is pulled in towards the black hole, gets ripped apart in the strong gravity, and emits high-energy X-ray radiation. This radiation reaches large distances, and is believed to have re-heated the cosmic gas, after it had cooled down as a result of the original cosmic expansion. The discovery in the new research is the delay of this heating.

The cosmic radio show

"It was previously believed that the heating occurred very early," says Prof. Barkana, "but we discovered that this standard picture delicately depends on the precise energy with which the X-rays come out. Taking into account up-to-date observations of nearby black-hole binaries changes the expectations for the history of cosmic heating. It results in a new prediction of an early time (when the universe was only 400 million years old) at which the sky was uniformly filled with radio waves emitted by the hydrogen gas."

In order to detect the expected radio waves from hydrogen in the early universe, several large international groups have built and begun operating new arrays of radio telescopes. These arrays were designed under the assumption that cosmic heating occurred too early to see, so instead the arrays can only search for a later cosmic event, in which radiation from stars broke up the hydrogen atoms out in the space in-between galaxies. The new discovery overturns the common view and implies that these radio telescopes may also detect the tell-tale signs of cosmic heating by the earliest black holes.


Story Source:

The above story is based on materials provided by American Friends of Tel Aviv University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Anastasia Fialkov, Rennan Barkana, Eli Visbal. The observable signature of late heating of the Universe during cosmic reionization. Nature, 2014; DOI: 10.1038/nature12999

Cite This Page:

American Friends of Tel Aviv University. "Early universe 'warmed up' later than previously believed: Research suggests a way to detect the earliest black holes." ScienceDaily. ScienceDaily, 5 February 2014. <www.sciencedaily.com/releases/2014/02/140205143802.htm>.
American Friends of Tel Aviv University. (2014, February 5). Early universe 'warmed up' later than previously believed: Research suggests a way to detect the earliest black holes. ScienceDaily. Retrieved August 27, 2014 from www.sciencedaily.com/releases/2014/02/140205143802.htm
American Friends of Tel Aviv University. "Early universe 'warmed up' later than previously believed: Research suggests a way to detect the earliest black holes." ScienceDaily. www.sciencedaily.com/releases/2014/02/140205143802.htm (accessed August 27, 2014).

Share This




More Space & Time News

Wednesday, August 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

SpaceX’s Falcon 9 Rocket Explodes After Liftoff

SpaceX’s Falcon 9 Rocket Explodes After Liftoff

Newsy (Aug. 23, 2014) — The private spaceflight company says it is preparing a thorough investigation into Friday's mishap. Video provided by Newsy
Powered by NewsLook.com
Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Newsy (Aug. 21, 2014) — Russian cosmonauts say they've found evidence of sea plankton on the International Space Station's windows. NASA is a little more skeptical. Video provided by Newsy
Powered by NewsLook.com
Space to Ground: Hello Georges

Space to Ground: Hello Georges

NASA (Aug. 18, 2014) — Europe's ATV-5 delivers new science and the crew tests smart SPHERES. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
Powered by NewsLook.com
Tiny Satellites, Like The One Tossed From ISS, On The Rise

Tiny Satellites, Like The One Tossed From ISS, On The Rise

Newsy (Aug. 18, 2014) — The Chasqui I, hand-delivered into orbit by a Russian cosmonaut, is one of hundreds of small satellites set to go up in the next few years. 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