Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Old but still warm: Far-UV detection of PSR B0950+08   We report on a Hubble Space Telescope detection of the nearby, old pulsar
B0950+08 ($d\simeq 262$ pc, spin-down age 17.5 Myr) in two far-ultraviolet
(FUV) bands. We measured the mean flux densities $\bar{f}_\nu = 109\pm 6$ nJy
and $83\pm 14$ nJy in the F125LP and F140LP filters (pivot wavelengths 1438 and
1528 \AA). Using the FUV data together with previously obtained optical-UV
data, we conclude that the optical-FUV spectrum consists of two components -- a
nonthermal (presumably magnetospheric) power-law spectrum ($f_\nu\propto
\nu^\alpha$) with slope $\alpha\sim -1.2$ and a thermal spectrum emitted from
the bulk of the neutron star surface with a temperature in the range of
$(1-3)\times 10^5$ K, depending on interstellar extinction and neutron star
radius. These temperatures are much higher than predicted by neutron star
cooling models for such an old pulsar, which means that some heating mechanisms
operate in neutron stars. A plausible mechanism responsible for the high
temperature of PSR B0950+08 is the interaction of vortex lines of the faster
rotating neutron superfluid with the slower rotating normal matter in the inner
neutron star crust (vortex creep heating).

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The categories of this paper are: adap-org
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The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: chao-dyn
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The categories of this paper are: cond-mat
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The categories of this paper are: physics
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The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
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The categories of this paper are: eess
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The categories of this paper are: funct-an
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The categories of this paper are: nlin
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The categories of this paper are: cmp-lg