Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Photometric Redshifts in lensing clusters: Identification and
  Calibration of faint high-z galaxies   We discuss a method aiming to use photometric redshifts in lensing clusters
to access the population of distant background sources. The amplification
provided by gravitational lensing allows to calibrate photometric redshifts 1
to 3 magnitudes deeper with respect to field studies. We present and discuss
some results obtained with this procedure on extensively studied clusters, as
well as the future issues of this project.

22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th