Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A cross-calibration between Tycho-2 photometry and HST spectrophotometry   I show that Tycho-2 photometry and HST spectrophotometry are accurate and
stable enough to obtain a precise cross-calibration by analyzing a
well-calibrated sample of 256 stars observed with both Hipparcos and HST. Based
on this analysis, I obtain the following photometric zero points in the Vega
magnitude system for Tycho-2: 0.020+-0.001 (B_T-V_T), 0.078+-0.009 (B_T), and
0.058+-0.009 (V_T).

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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
3
The categories of this paper are: physics