Grbs in a sentence

The IPN detects gamma ray bursts (GRBs); since gamma rays cannot be focused with mirrors, it was very difficult to locate GRBs with enough accuracy to study them further.

We detect GRBs when one of these jets points almost directly toward Earth.

Additional support for focusing of the output of GRBs has come from observations of strong asymmetries in the spectra of nearby type Ic supernova Mazzali 2005 and from radio observations taken long after bursts when their jets are no longer relativistic.

Estimates of rate of occurrence of short-duration GRBs are even more uncertain because of the unknown degree of collimation, but are probably comparable.

Furthermore, galaxies with a redshift of z higher than 0.5 are unsuitable for life as we know it, due to their higher rate of GRBs and their stellar compactness.

Gamma-ray bursts Gamma-ray bursts (GRBs) are candidates for extraterrestrial communication.

Hypothetical effects on Earth in the past GRBs close enough to affect life in some way might occur once every five million years or so – around a thousand times since life on Earth began.

Lamb 1995 Counterpart objects as candidate sources For decades after the discovery of GRBs, astronomers searched for a counterpart at other wavelengths: i.e., any astronomical object in positional coincidence with a recently observed burst.

Most of this energy is released in gamma rays, although some GRBs have extremely luminous optical counterparts as well.

Prochaska 2006 The degree of beaming in short bursts has not been accurately measured, but as a population they are likely less collimated than long GRBs Watson 2006 or possibly not collimated at all in some cases.

Simpson and Dean (2002) A Gamma ray burst (GRB) found in conjunction with a supernova has been called a Rosetta Stone for understanding the origin of GRBs.

The absence of any such pattern in the case of GRBs provided strong evidence that gamma-ray bursts must come from beyond the Milky Way.

The association of some long GRBs with supernovae and the fact that their host galaxies are rapidly star-forming offer very strong evidence that long gamma-ray bursts are associated with massive stars.

These discoveries, and subsequent studies of the galaxies and supernovae associated with the bursts, clarified the distance and luminosity of GRBs.

These facts definitively placed them in distant galaxies and also connected long GRBs with the explosion of massive stars, the only possible source for the energy outputs observed.

This event had a gamma-ray duration of about 2 days, much longer than even ultra-long GRBs, and was detected in X-rays for many months.

Very bright supernovae have been observed to accompany several of the nearest GRBs.