Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Test for Large-Scale Systematic Errors in Maps of Galactic Reddening   Accurate maps of Galactic reddening are important for a number of
applications, such as mapping the peculiar velocity field in the nearby
Universe. Of particular concern are systematic errors which vary slowly as a
function of position on the sky, as these would induce spurious bulk flow. We
have compared the reddenings of Burstein & Heiles (BH) and those of Schlegel,
Finkbeiner & Davis (SFD) to independent estimates of the reddening, for
Galactic latitudes |b| > 10. Our primary source of Galactic reddening estimates
comes from comparing the difference between the observed B-V colors of
early-type galaxies, and the predicted B-V color determined from the B-V--Mg_2
relation. We have fitted a dipole to the residuals in order to look for
large-scale systematic deviations. There is marginal evidence for a dipolar
residual in the comparison between the SFD maps and the observed early-type
galaxy reddenings. If this is due to an error in the SFD maps, then it can be
corrected with a small (13%) multiplicative dipole term. We argue, however,
that this difference is more likely to be due to a small (0.01 mag.) systematic
error in the measured B-V colors of the early-type galaxies. This
interpretation is supported by a smaller, independent data set (globular
cluster and RR Lyrae stars), which yields a result inconsistent with the
early-type galaxy residual dipole. BH reddenings are found to have no
significant systematic residuals, apart from the known problem in the region
230 < l < 310, -20 < b < 20.

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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: mtrl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: funct-an
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ph
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: cs
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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: eess