The Optical Redshift Survey
Marc Davis, Alan Dressler, Harold Corwin
The Optical Redshift Survey (ORS) contains 8457 galaxies
covering a solid angle of 8.09 sterad (about 2/3 of the sky).
It is a compilation of previous wide-angle redshift
surveys plus about 1300 new redshift measurements.
The figure above shows on-sky projections of the
sample galaxies with a grid in Galactic coordinates. The upper
panel shows hemispheric projections whereas the lower one
shows an Aitoff projection. The diagonal lines across both panels
indicate the ESGC strip (see below).
The sample avoids a 40 degrees strip in the Plane of the Galaxy
plus regions where the B band absorption coefficient is
A_B > 0.7 mag (these latter are shown as dark areas in the figure).
The sample is 98% complete in redshift and was defined according
to the following selection criteria:
- Galaxies whose apparent B band magnitudes are brighter than 14.5.
We call this subset ORS-m.
OR
- Galaxies whose apparent B band diameters are larger than 1.9'.
This subset we call ORS-d.
The ORS sample was drawn by applying these selection criteria to 3 major
galaxy catalogs: the ESO-Uppsala Survey of the ESO(B) Atlas
in declinations south of -17.5 degrees; the Uppsala General Catalogue
(UGC) for declinations north of -2.5 degrees; the Extension to the
Southern Galaxies Catalogue (ESGC) for the [-17.5, -2.5] declination
strip.
The new redshifts were obtained in several observatories and telescopes:
the 3m telescope at Lick Observatory (Univ. of California), the
1.5m telescope and the Multiple Mirror Telescope at Mt Hopkins
Observatory (SAO and Univ. of Arizona),
the 1.5m CTIO telescope, the 1.5m telescope at
Palomar Observatory (Caltech, OCIW
and Cornell Univ.) and the 2.1m telescope at Las Campanas (OCIW).
ORS provides a dense sampling of the galaxy distribution out
to redshift velocities of about 8000 km/s. It is thus ideal for
studying the properties of the galaxy distribution in the Local
Universe, its clustering properties, galaxy segregation, main
large scale structures, their shape, size and density contrast, etc.
A list of ORS papers ,
both published and in preparation is also available.
Retrieve the ORS data in different formats (just press the shift button
on your keyboard at the same time you click with the mouse buttom on the
desired link).
- Master files containing the ESO , UGC and
ESGC galaxy catalogues with the ORS redshifts in them.
- ORSd + ORSm sample files again separated in the three regions:
ESO , UGC and
ESGC .
Basilio Santiago, santiago@if.ufrgs.br