Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Identifying young gamma-ray burst fossils   The recent reports of temporal and spectral peculiarities in the early stages
of some afterglows suggest that we may be wrong in postulating a central engine
which becomes dormant after the burst itself. A continually decreasing
postburst relativistic outflow, such as put out by a decaying magnetar, may
continue to be emitted for periods of days or longer, and we argue that it can
be efficiently reprocessed by the ambient soft photon field radiation. Photons
produced either by the postexplosion expansion of the progenitor stellar
envelope or by a binary companion provide ample targets for the relativistic
outflow to interact and produce high energy gamma-rays. The resultant signal
may yield luminosities high enough to be detected with the recently launched
Integral and the Glast experiment now under construction. Its detection will
surely offer important clues for identifying the nature of the progenitor and
possibly constraining whether some route other than single star evolution is
involved in producing a rapidly rotating helium core which in turn, at
collapse, triggers a burst.

29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs