Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Revisiting Ulysses Observations of Interstellar Helium   We report the results of a comprehensive reanalysis of Ulysses observations
of interstellar He atoms flowing through the solar system, the goal being to
reassess the interstellar He flow vector and to search for evidence of
variability in this vector. We find no evidence that the He beam seen by
Ulysses changes at all from 1994-2007. The direction of flow changes by no more
than ~0.3 deg and the speed by no more than ~0.3 km/s. A global fit to all
acceptable He beam maps from 1994-2007 yields the following He flow parameters:
V_ISM=26.08+/-0.21 km/s, lambda=75.54+/-0.19 deg, beta=-5.44+/-0.24 deg, and
T=7260+/-270 K; where lambda and beta are the ecliptic longitude and latitude
direction in J2000 coordinates. The flow vector is consistent with the original
analysis of the Ulysses team, but our temperature is significantly higher. The
higher temperature somewhat mitigates a discrepancy that exists in the He flow
parameters measured by Ulysses and the Interstellar Boundary Explorer, but does
not resolve it entirely. Using a novel technique to infer photoionization loss
rates directly from Ulysses data, we estimate a density of n_He=0.0196+/-0.0033
cm^-3 in the interstellar medium.

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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
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The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
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The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
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The categories of this paper are: supr-con
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The categories of this paper are: physics
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The categories of this paper are: atom-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: patt-sol
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The categories of this paper are: stat
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-fin