Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Seeing relativity -- I. Ray tracing in a Schwarzschild metric to explore
  the maximal analytic extension of the metric and making a proper rendering of
  the stars   We present an implementation of a ray tracing code in the Schwarzschild
metric. We aim at building a numerical code with a correct implementation of
both special (aberration, amplification, Doppler) and general (deflection of
light, lensing, gravitational redshift) relativistic effects so as to simulate
what an observer with arbitrary velocity would see near, or possibly within,
the black hole. We also pay some specific attention to perform a satisfactory
rendering of stars. Using this code, we then show several unexplored features
of the maximal analytical extension of the metric. In particular, we study the
aspect of the second asymptotic region of the metric as seen by an observer
crossing the horizon. We also address several aspects related to the white hole
region (i.e., past singularity) seen both from outside the black hole, inside
the future horizon and inside the past horizon, which gives rise to the most
counter-intuitive effects.

27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph