FACTOID # 16: In the 2000 Presidential Election, Texas gave Ralph Nader the 3rd highest popular vote count of any US state.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > GRB 970228

On February 28, 1997, BeppoSAX managed to pin down the location of an optical counterpart to a gamma ray burst, which was designated GRB 970228 in accordance with the date of the event. 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. February 28 is the 59th day of the year in the Gregorian Calendar. ... BeppoSAX was an Italian-Dutch satellite for X-ray astronomy. ... Optical afterglow of gamma ray burst GRB-990123 (the bright dot within the white square and in the enlarged cutout) on 23 January 1999. ...


Then, on May 8, 1997, BeppoSAX recorded another burst in the constellation Camelopardalis, and 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. May 8 is the 128th day of the year in the Gregorian Calendar (129th in leap years). ... Camelopardalis, Latin for giraffe, is the name of a large but faint northern constellation first recorded by Jakob Bartsch in 1624, but probably created earlier by Petrus Plancius. ... The Kitt Peak National Observatory (KPNO) is located on a 6,875 ft peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono Oodham Nation, 55 miles southwest of Tucson. ... State nickname: The Grand Canyon State, The Copper State Other U.S. States Capital Phoenix Largest city Phoenix [[List of Governors of {{{Name}}}|Governor]] Janet Napolitano Official languages English Only State Area 295,254 km² (6th)  - Land 294,312 km²  - Water 942 km² (0. ...


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. May 11 is the 131st day of the year in the Gregorian Calendar (132nd in leap years). ... The Mauna Kea Observatory, an institute of the University of Hawaii, is considered one of the most important land-based observatories in the world for its isolated, unobstructed views of space without interference from man-made light sources. ... Mauna Kea is a dormant volcano in the Hawaiian Islands, one of five volcanic peaks that together form the Island of Hawaii. ... The electromagnetic spectrum encompasses all possible wavelengths of electromagnetic radiation. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ...


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. The Doppler effect is the apparent change in frequency or wavelength of a wave that is perceived by an observer moving relative to the source of the waves. ... This article is about the light phenomenon. ...


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. The proper motion of a star is the motion of the position of the star in the sky (the change in direction in which we see it, as opposed to the radial velocity) after eliminating the improper motions of the stars, which affect their measured coordinates but are not real...


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. The Hubble Space Telescope (HST) is a telescope orbiting the Earth at the outer edges of the atmosphere. ... The proper motion of a star is the motion of the position of the star in the sky (the change in direction in which we see it, as opposed to the radial velocity) after eliminating the improper motions of the stars, which affect their measured coordinates but are not real...


  Results from FactBites:
 
Gamma Ray Bursts (2064 words)
GRB 970228 was the first of these incredibly energetic events to be seen glowing afterward in X-rays and visible light.
GRB 971214 (discovered Dec. 14, 1997), at one time thought to be the physical representative of this model of GRB formation, started the theorists really scratching their heads because the source was too bright to match the preferred model of two neutron stars colliding.
GRB 970228 (the numbers are the date of the burst) is the landmark sighting because it was the first optical component to be captured in visible light.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m