Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Luminous Cluster Ellipticals as Cosmological Standard Rods?   We explore the possibility to calibrate massive cluster ellipticals as
cosmological standard rods. The method is based on the Fundamental Plane
relation combined with a correction for luminosity evolution which is derived
from the Mg$-\sigma$ relation. Principle caveats and sources of major errors
are briefly discussed.
  We apply the described procedure to nine elliptical galaxies in two clusters
at $z=0.375$ and derive constraints on the cosmological model. For the best
fitting $\Lambda$-free cosmological model we obtain: $q_o \approx 0.1$, with
90% confidence limits being $0 < q_o < 0.7$ (the lower limit being due to the
presence of matter in the Universe). If the inflationary scenario applies
(i.e., space has flat geometry), then, for the best fitting model, matter and
$\Lambda$ contribute about equally to the critical cosmic density (i.e.
$\Omega_m \approx \Omega_\Lambda \approx 0.5$). With 90% confidence
$\Omega_\Lambda$ should be smaller than 0.9.

15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ