Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermal and Non-thermal radiation from pulsars: hints of physics   Thermal and non-thermal radiation from pulsars carries significant
information from surface and would have profound implications on the state of
dense matter in compact stars. For the non-thermal radio emission, subpulse
drifting phenomena suggest the existence of Ruderman-Sutherland-like
gap-sparking and strong binding of particles on pulsar polar caps. While
conventional neutron star models can hardly provide such a high binding energy,
the strong self-bound surface of quark-cluster stars can naturally solve this
problem. As for the thermal one, the featureless X-ray spectra of pulsars may
indicate a bare surface without atmosphere, and the ultrarelativistic fireball
of gamma-ray bursts and supernovae would also require strong self-bound
surfaces. Recent achievements in measuring pulsar mass and mass-radius relation
further indicate a stiff equation of state and a self-bound surface. Therefore,
we conjecture that matters inside pulsar-like compact stars could be in a
quark-cluster phase. The surface of quark-cluster stars is chromatically
confined and could initially be bare. Such a surface can not only explain above
features, but may also promote a successful core-collapse supernova, and the
hydro-cyclotron oscillation of the electron sea above the surface could be
responsible for those absorption features detected in the X-ray spectrum.

31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph