In our previous work  it was reported that adding of small amount of oxygen into a low pressure nitrogen plasma afterglow
causes an increase of nitrogen atom density.
But in February 2014, a 1.2-meter telescope in Southern California spotted a visible-light flash that brightened dramatically within about an hour, fitting the profile of a burst's afterglow
. Sure enough, the next day, astronomers looked back at data from three satellites and found a surge of gamma rays consistent with a burst.
Over the following 10 minutes, RINGO2 collected 5,600 photographs of the burst afterglow
while the properties of the magnetic field were still encoded in its captured light.
The study shows that dark bursts must be similar, except for the dusty patches in their host galaxies that obscure most of the light in their afterglows
This allows Swift to catch afterglows
in their brightest early phases, seconds to minutes after the explosion.
Nearly all the afterglows
that astronomers have detected come from gamma-ray bursts that arose in galaxies that lie 2 billion to 8 billion light-years away.
Within an hour, astronomers began training ground-based telescopes on the same patch of sky to study the burst's infrared afterglow
Fortunately, three more short-burst afterglows
were detected last summer, one by the HETE-2 instrument and two others by Swift (S&T: December 2005, page 21).
Previous X-ray images had captured a burst's afterglow
, but not the burst itself, notes Swift principal investigator Neil Gehrels of NASA's Goddard Space Flight Center in Greenbelt, Md.
Nearly 32 hours after the blast, Jochen Greiner of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, led a group that searched for the explosion's fading afterglow
Hubble Space Telescope afterglow
observations of the July 9th burst are particularly significant.
fade rapidly, we really had to scramble when we received the alert," Perley said.