Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analysis of Longitudinal Air Shower Profiles measured by the Pierre
  Auger Observatory   We describe the analysis of longitudinal air shower profiles as measured by
the fluorescence detectors of the Pierre Auger Observatory and present the
measurement of the depth of maximum of extensive air showers, Xmax, with
energies >10^18 eV. The measured energy evolution of the average of Xmax and
its fluctuations are compared to air shower simulations for different primary
particles.

12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph