Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical/Infrared Observations of the Anomalous X-ray Pulsar 1E
  1048.1-5937 During Its 2007 X-Ray Flare   We report on optical and infrared observations of the anomalous X-ray pulsar
(AXP) 1E 1048.1-5937, made during its ongoing X-ray flare which started in 2007
March. We detected the source in the optical I and near-infrared Ks bands in
two ground-based observations and obtained deep flux upper limits from four
observations, including one with the Spitzer Space Telescope at 4.5 and 8.0
microns. The detections indicate that the source was approximately 1.3--1.6
magnitudes brighter than in 2003--2006, when it was at the tail of a previous
similar X-ray flare. Similar related flux variations have been seen in two
other AXPs during their X-ray outbursts, suggesting common behavior for large
X-ray flux variation events in AXPs. The Spitzer flux 1E 1048.1-5937 limits are
sufficiently deep that we can exclude mid-infrared emission similar to that
from the AXP 4U 0142+61, which has been interpreted as arising from a dust disk
around the AXP. The optical/near-infrared emission from probably has a
magnetospheric origin. The similarity in the flux spectra of 4U 0142+61 and 1E
1048.1-5937 challenges the dust disk model proposed for the latter.

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The categories of this paper are: gr-qc
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: acc-phys
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The categories of this paper are: cond-mat
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The categories of this paper are: supr-con
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
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The categories of this paper are: math
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The categories of this paper are: solv-int