Featured Research

from universities, journals, and other organizations

Star Death Beacon At The Edge Of The Universe

September 20, 2005
European Southern Observatory
An Italian team of astronomers has observed the afterglow of a Gamma-Ray Burst that is the farthest known ever. With a measured redshift of 6.3, the light from this very remote astronomical source has taken 12,700 million years to reach us. It is thus seen when the Universe was less than 900 million years old, or less than 7 percent its present age.

The Distant Gamma-Ray Burst GRB 050904. This photo shows the position of the distant Gamma-Ray Burst GRB 050904. The image is a colour-composite based on images obtained with ISAAC on the VLT in three different bands in the near-infrared (J, H and K).
Credit: Image courtesy of European Southern Observatory

"This also means that it is among theintrinsically brightest Gamma-Ray Burst ever observed", said GuidoChincarini from INAF-Osservatorio Astronomico di Brera and Universityof Milano-Bicocca (Italy) and leader of a team that studied the objectwith ESO's Very Large Telescope. "Its luminosity is such that within afew minutes it must have released 300 times more energy than the Sunwill release during its entire life of 10,000 million years."

Gamma-raybursts (GRBs) are short flashes of energetic gamma-rays lasting fromless than a second to several minutes. They release a tremendousquantity of energy in this short time making them the most powerfulevents since the Big Bang. It is now widely accepted that the majorityof the gamma-ray bursts signal the explosion of very massive, highlyevolved stars that collapse into black holes.

This discovery notonly sets a new astronomical record, it is also fundamental to theunderstanding of the very young Universe. Being such powerful emitters,these Gamma Ray Bursts serve as useful beacons, enabling the study ofthe physical conditions that prevailed in the early Universe. Indeed,since GRBs are so luminous, they have the potential to outshine themost distant known galaxies and may thus probe the Universe at higherredshifts than currently known. And because Gamma-ray Burst are thoughtto be associated with the catastrophic death of very massive stars thatcollapse into black holes, the existence of such objects so early inthe life of the Universe provide astronomers with important informationto better understand its evolution.

The Gamma-Ray Burst GRB050904was first detected on September 4, 2005, by the NASA/ASI/PPARC Swiftsatellite, which is dedicated to the discovery of these powerfulexplosions.

Immediately after this detection, astronomers inobservatories worldwide tried to identify the source by searching forthe afterglow in the visible and/or near-infrared, and study it.

Firstobservations by American astronomers with the Palomar Robotic 60-inchTelescope failed to find the source. This sets a very stringent limit:in the visible, the afterglow should thus be at least a million timesfainter than the faintest object that can be seen with the unaided eye(magnitude 21). But observations by another team of Americanastronomers detected the source in the near-infrared J-band with amagnitude 17.5, i.e. at least 25 times brighter than in the visible.

Thiswas indicative of the fact that the object must either be very far awayor hidden beyond a large quantity of obscuring dust. Furtherobservations indicated that the latter explanation did not hold andthat the Gamma-Ray Burst must lie at a distance larger than 12,500million light-years. It would thus be the farthest Gamma-Ray Burst everdetected.

Italian astronomers forming the MISTICI collaboration[1] then used Antu, one of four 8.2-m telescopes that comprise ESO'sVery Large Telescope (VLT) to observe the object in the near-infraredwith ISAAC and in the visible with FORS2. Observations were donebetween 24.7 and 26 hours after the burst.

Indeed, the afterglowwas detected in all five bands in which they observed (the visible I-and z-bands, and the near-infrared J, H, and K-bands). By comparing thebrightness of the source in the various bands, the astronomers coulddeduce its redshift and, hence, its distance. "The value we derived hassince then been confirmed by spectroscopic observations made by anotherteam using the Subaru telescope", said Angelo Antonelli (RomaObservatory), another member of the team.


[1]: TheMISTICI collaboration consists of astronomers from OsservatorioAstronomico di Roma (INAF), Osservatorio Astronomico di Brera (INAF),Osservatorio Astronomico di Arcetri (INAF), Universita` degli Studi diMilano - Bicocca, International School for Advanced Studies (SISSA) andObservatori Astronomic of Universitat de Valencia (Spain). Inparticular, Angelo Antonelli, Daniele Malesani, Vincenzo Testa, PaoloD'Avanzo, Stefano Covino, Alberto Fernandez-Soto, GianpieroTagliaferri, Guido Chincarini, Sergio Campana, Massimo Della Valle,Felix Mirabel, and Luigi Stella were notably active with the dataanalysis and observations. Prof. Guido Chincarini is the ItalianPrincipal Investigator of the Italian research on GRBs related to theSwift satellite, which is funded by the Italian Space Agency (ASI).

Story Source:

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

Cite This Page:

European Southern Observatory. "Star Death Beacon At The Edge Of The Universe." ScienceDaily. ScienceDaily, 20 September 2005. <www.sciencedaily.com/releases/2005/09/050920081931.htm>.
European Southern Observatory. (2005, September 20). Star Death Beacon At The Edge Of The Universe. ScienceDaily. Retrieved September 15, 2014 from www.sciencedaily.com/releases/2005/09/050920081931.htm
European Southern Observatory. "Star Death Beacon At The Edge Of The Universe." ScienceDaily. www.sciencedaily.com/releases/2005/09/050920081931.htm (accessed September 15, 2014).

Share This

More Space & Time News

Monday, September 15, 2014

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

NASA’s Curiosity Rover Finally Reaches Long-Term Goal

NASA’s Curiosity Rover Finally Reaches Long-Term Goal

Newsy (Sep. 15, 2014) — After more than two years, NASA’s Mars Curiosity Rover reached Mount Sharp, its long-term destination. Video provided by Newsy
Powered by NewsLook.com
SpaceX's Elon Musk Really Wants To Colonize Mars

SpaceX's Elon Musk Really Wants To Colonize Mars

Newsy (Sep. 14, 2014) — Elon Musk has been talking about his goal of colonizing Mars for years now, but how much of it does he actually have figured out, and is it possible? Video provided by Newsy
Powered by NewsLook.com
International Space Station Crew Returns Safely To Earth

International Space Station Crew Returns Safely To Earth

Newsy (Sep. 11, 2014) — The three-man crew touched down in Kazakhstan Wednesday after more than five months of science experiments in orbit. Video provided by Newsy
Powered by NewsLook.com
Solar Storm To Hit This Weekend, Scientists Not Worried

Solar Storm To Hit This Weekend, Scientists Not Worried

Newsy (Sep. 11, 2014) — Two solar flares which erupted in our direction this week will arrive this weekend. The resulting solar storm will be powerful but not dangerous. 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.


Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News


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