Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mid-UV Studies of the Transitional Millisecond Pulsars XSS J12270-4859
  and PSR J1023+0038 During Their Radio Pulsar States   We report mid-UV (MUV) observations taken with HST/WFC3, Swift/UVOT and
GALEX/NUV of the transitional millisecond pulsars XSS J12270-4859 and PSR
J1023+0038 during their radio pulsar states. Both systems were detected in our
images and showed MUV variability. At similar orbital phases, the MUV
luminosities of both pulsars are comparable. This suggests that the emission
processes involved in both objects are similar. We estimated limits on the mass
ratio, companion's temperature, inclination, and distance to XSS J12270-4859 by
using a Markov Chain Monte Carlo algorithm to fit published folded optical
light curves. Using the resulting parameters, we modeled MUV light curves in
our HST filters. The resulting models failed to fit our MUV observations.
Fixing the mass ratio of XSS J12270-4859 to the value reported in other
studies, we obtained a distance of ~3.2 kpc. This is larger than the one
derived from radio measurements (~1.4 kpc). Assuming a uniform prior for the
mass ratio, the distance is similar to that from radio measurements. However,
it requires an undermassive companion (~0.01 M_sun). We conclude that a direct
heating model alone can not fully explain the observations in optical and MUV.
Therefore, an additional radiation source is needed. The source could be an
intrabinary shock which contributes to the MUV flux and likely to the optical
one as well. During the radio pulsar state, the MUV orbital variations of PSR
J1023+0038 detected with GALEX, suggests the presence of an asymmetric
intrabinary shock.

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The categories of this paper are: q-alg
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The categories of this paper are: eess
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The categories of this paper are: gr-qc
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The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
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The categories of this paper are: physics
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The categories of this paper are: hep-th
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The categories of this paper are: solv-int
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The categories of this paper are: supr-con
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The categories of this paper are: ao-sci
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The categories of this paper are: q-bio
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: stat
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The categories of this paper are: funct-an