Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Microlensing in M31 - The MEGA Survey's Prospects and Initial Results   January 2000 completes the first season of intensive, wide-field observations
of microlensing and stellar variability in M31 by MEGA (Microlensing
Exploration of the Galaxy and Andromeda) at the Isaac Newton 2.5m Telescope,
the KPNO 4m, and the 1.3m and 2.5m telescopes of MDM Observatory. In
preliminary analysis, we detect ~50000 variable objects, including some
consistent with microlensing events. We present the level of sensitivity to be
reached in our planned three-year program to test for the presence of a
significant halo microlensing population in M31, as well as its spatial
distribution and mass-function. We also discuss our application of image
subtraction to these wide fields and HST WFPC2 Snapshot followup observations
to confirm candidates identified from previous years' surveys.
  We present intermediate results from our smaller-field survey, on the MDM
1.3m and Vatican Advanced Technology 1.8m Telescope, from 1994-1998, wherein we
have discovered 8 additional probable microlensing events, over about one-half
the time base of the project, in addition to confirming three of our original 6
microlensing candidates from 1995.

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The categories of this paper are: cs
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
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The categories of this paper are: hep-ex
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The categories of this paper are: physics
21
The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg