Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: BeppoSAX observations of the young pulsar in the Kes 75 Supernova
  Remnant   We present the results of BeppoSAX observations of the young X-ray pulsar PSR
J1846-0258, recently discovered at the center of the composite supernova
remnant Kes 75. The pulsar (plus nebula) spectrum can be fitted by an absorbed
power law with photon index alpha_ph=2.16+/-0.15, N_H=(4.7+/-0.8) x 10^22
cm^-2, and unabsorbed flux ~3.9x10^-11 erg cm^-2 s^-1 (2-10 keV). By joining
two observations taken at an interval of two weeks we have been able to obtain
a precise measurement of the spin period (P=324.818968+/-0.000006 ms). This
value, when combined with previous measurements, cannot be fitted by a smooth
frequency evolution with a canonical braking index n=3. With the hypothesis of
no glitches and/or significant timing noise, the braking index would be
n=1.86+/-0.08 and, assuming a short initial period, the pulsar age would be
\~1700 years, closer to that of the supernova remnant than the simple estimate
\tau=P/2\pdot=723 years. Other likely possibilities involve the presence of
glitches and lead to a wide range of acceptable ages. For example, we obtain n
in the range 1.8-2.5, if a glitch occurred near MJD 51500, while for a glitch
between October 1993 and March 1999 we can only get a lower limit of n>1.89.

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The categories of this paper are: comp-gas
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The categories of this paper are: eess
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-bio
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The categories of this paper are: cond-mat
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The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: physics
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The categories of this paper are: patt-sol