Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The evolution of GRB remnants   The detection of the delayed emission in X-ray, optical and radio band, i.e.
the afterglow of $\gamma$-ray bursts (GRBs), suggestes that the sources of GRBs
are likely to be at cosmological distances. Here we explore the interaction of
a relativistic shell with a uniform interstellar medium (ISM) and obtain the
exact solution of the evolution of $\gamma$-ray burst remnants, including the
radiative losses. We show that in general the evolution of bulk Lorentz factor
$\gamma$ satisfies $\gamma \propto t^{-\alpha_{t}}$ when $\gamma \gg 1$, here
$\alpha_{t}$ is mainly in the range $9/22 \sim 3/8$, the latter corresponds to
adiabatic expansion. So it is clear that adiabatic expansion is a good
approximation even when radiative loss is considered. However, in fact,
$\alpha_{t}$ is slightly larger than 3/8, which may have some effects on a
detailed data analysis. Synchrotron-self-absorption is also calculated and it
is demonstrated that the radio emission may become optically thin during the
afterglow. Our solution can also apply to the nonrelativistic case ($\gamma
\sim 1$), at that time the observed flux decrease more rapidly than that in the
relativistic case.

8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat