Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The properties of powerful radio sources at 90 GHz   We have observed a small sample of powerful double radio sources (radio
galaxies and quasars) at frequencies around 90 GHz with the BIMA millimetre
array, with the intention of constraining the resolved high-frequency spectra
of radio galaxies. When combined with other sources we have previously observed
and with data from the BIMA archive, these observations allow us for the first
time to make general statements about the high-frequency behaviour of compact
components of radio galaxies -- cores, jets and hotspots. We find that cores in
our sample remain flat-spectrum up to 90 GHz; jets in some of our targets are
detected at 90 GHz for the first time in our new observations; and hotspots are
found to be almost universal, but show a wide range of spectral properties.
Emission from the extended lobes of radio galaxies is detected in a few cases
and shows rough consistency with the expectations from standard spectral ageing
models, though our ability to probe this in detail is limited by the
sensitivity of BIMA. We briefly discuss the prospects for radio-galaxy
astrophysics with ALMA.

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The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: atom-ph
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The categories of this paper are: stat
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
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The categories of this paper are: mtrl-th
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: q-bio
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The categories of this paper are: math-ph