Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cosmological X-Ray Flashes from Off-Axis Jets   The <V/Vmax> of the cosmological X-ray flashes detected by WFC/BeppoSAX is
calculated theoretically in a simple jet model. The total emission energy from
the jet is assumed to be constant. We find that if the jet opening half-angle
is smaller than 0.03 radian, off-axis emission from sources at z<~4 can be
seen. The theoretical <V/Vmax> is less than 0.4, which is consistent with the
observational result of 0.27+/-0.16 at the 1-sigma level. This suggests that
the off-axis GRB jet with the small opening half-angle at the cosmological
distance can be identified as the cosmological X-ray flash.

10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex