Everything about Grb 970228 totally explained
GRB 970228 was a
gamma ray burst (GRB) that occurred on
February 28,
1997 which was designated in accordance with the date of the event.
The
BeppoSAX satellite located the optical counterpart to the GRB. Some observations seemed to show the object was moving rapidly across the sky. That meant it couldn't be too far away, implying the bursts are a local phenomenon.
On
May 8, 1997, BeppoSAX recorded another burst in the constellation
Camelopardalis. The spacecraft's science team sent out an alert over the Internet. Seven hours later, an optical source was detected by astronomer
Howard Bond, using a 90-centimeter telescope at
Kitt Peak National Observatory in
Arizona.
On
May 11, astronomers used the 10 meter
Keck II telescope on the island of
Mauna Kea,
Hawaii, to obtain a
spectrum of the object. The spectrum showed
absorption lines, or frequencies where the light was absorbed by gases between the object and Earth. The patterns of absorption lines are specific to different atoms and molecules.
The motion of an object causes a
Doppler shift in the wavelengths of these lines, with the expansion of the Universe causing a
redshift towards longer wavelengths. The amount of redshift is proportional to the distance of the object, and in this case the spectrum showed a redshift of 0.835, indicating the object was billions of light-years away.
Astronomers were baffled. One observation indicated a local origin, the other a distant origin. Astronomers suspected that at least one of the correlated optical sources may have had nothing to do with a gamma-ray burst, and simply happened to be in the right place at the right time. Some astronomers were also unable to detect any
proper motion in the object linked to GRB 970228.
Following these observations, astronomers were able to track down more faint visible-light and radio afterglows of GRBs, hours or days after the occurrence of the burst. A few more redshifts were obtained, and confirmed that the bursts occurred in the distant cosmos. The high proper motion reported for GRB 970228 was clearly erroneous, and in fact observations made by the
Hubble Space Telescope in September
1997 showed no
proper motion in the faint afterglow that remained from GRB 970228.
Further Information
Get more info on 'Grb 970228'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://grb_970228.totallyexplained.com">GRB 970228 Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |