Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Jiamusi pulsar observations: III. Nulling of 20 pulsars   Most of pulsar nulling observations were conducted at frequencies lower than
1400~MHz. We aim to understand the nulling behaviors of pulsars at relatively
high frequency, and to check if nulling is caused by a global change of pulsar
magnetosphere. 20 bright pulsars are observed at 2250~MHz with unprecedented
lengths of time by using Jiamusi 66m telescope. Nulling fractions of these
pulsars are estimated, and the null and emission states of pulses are
identified. Nulling degrees and scales of the emission-null pairs are
calculated to describe the distributions of emission and null lengths. Three
pulsars, PSRs J0248+6021, J0543+2329 and J1844+00, are found to null for the
first time. The details of null-to-emission and emission-to-null transitions
within pulse window are first observed for PSR J1509+5531, which is a small
probability event. A complete cycle of long nulls for hours is observed for PSR
J1709-1640. For most of these pulsars, the K-S tests of nulling degrees and
nulling scales reject the hypothesis that null and emission are of random
processes at high significance levels. Emission-null sequences of some pulsars
exhibit quasi-periodic, low-frequency or featureless modulations, which might
be related to different origins. During transitions between emission and null
states, pulse intensities have diverse tendencies for variations. Significant
correlations are found for nulling fraction, nulling cadence and nulling scales
with the energy loss rate of the pulsars. Combined with the nulling fractions
reported in literatures for 146 nulling pulsars, we found that statistically
large nulling fractions are more tightly related to pulsar period than to
characteristic age or energy loss rate.

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The categories of this paper are: cs
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The categories of this paper are: chem-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: nlin
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The categories of this paper are: physics
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: acc-phys
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The categories of this paper are: plasm-ph