Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Redshifts of the Gravitational Lenses B1422+231 and PG1115+080   B1422+231 and PG1115+080 are gravitational lens systems producing quadruple
QSO images where there is real promise that time delays can constrain the
Hubble constant. In addition, the lensing galaxies are both part of groups
which can play an important role in modelling the lens potential. This article
reports redshifts for the lensing galaxies and three neighboring galaxies in
each of the two systems. B1422+231 consists of a group at z=0.339 with a
dispersion of 733 km/s, and PG1115+080 is a group at z=0.311 with a dispersion
of 326 km/s. One of the neighboring galaxies in the B1422+231 system turned out
to be an emission line galaxy at z=0.536, suggesting that QSO light passing
through B1422+231 may have been subjected to lensing by a cluster at this more
distant redshift. The velocity dispersion of the lensing galaxy in PG1115+080
is determined to be 281+/-25 km/s (1" square aperture), which is surprisingly
large given the image splittings of 1.2" in that system.

23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
1
The categories of this paper are: cs