Astrophysical Tests of Gravity: A Screening Map of the Nearby Universe

Based on the paper by: Cabre, Vikram, Zhao, Jain and Koyama (2012)
Paper on astro-ph

Input catalogs

This web page provides information and code to implement the screening criterion presented in Cabre et al (2012). The purpose of the catalogs linked below is to test for environmental screening of a test galaxy with known position on the sky and estimated distance. In order to create a screening map (the environmental part), one needs to have a complete neighbor catalog. We use four catalogs of galaxies, groups and clusters that extend to redshift 0.05 or a distance of 210 Mpc. Individual distances are obtained from the redshift using Hubble's law, using H0=72 km/s/Mpc.Masses are estimated as described in Cabre et al and the papers cited below. There are several caveats and limitations to the screening maps as described in Cabre et al. Please contact the authors (see econtact information below) if you wish to use these catalogs.

SDSS groups

Yang et al have kindly provided us their SDSS group catalog, which we use over the redshift range z=0.01-0.05. However, this catalog is not useful for objects at less than 50 Mpc.

NASA ADS

SDSS Group webpage

2 MASS groups

We use the group catalog from 2M++ all sky survey (Lavaux and Hudson, 2011). There are 3984 2M++ groups of galaxies that extend to redshift 0.05 for the bigger groups.

2 MASS

Galaxy catalog within Mpc

We use the catalog from Karachentsev et al (2004). Distances and masses are given by them. This catalog goes down to much lower masses than the more distant catalogs.
Format: RA (deg), DEC (deg), Distance (Mpc), Mass (solar)

10 Mpc

Cluster catalog

We compiled a catalog of clusters with known redshifts using the Abell (Abell, Corwin and Olowin 1989) and ROSAT (Ebeling et al 1996) bright clusters. We ignore clusters from the Abell catalog that lack spectroscopic redshift. Our final catalog has 675 clusters of galaxies.
Format: RA (deg), DEC (deg), Distance (Mpc), Mass (solar masses)

Clusters

Screening code

Here you can download the phyton code used to determine the environmental screening at a given point (ra,dec,estimated distance) based on the estimated external potential.

The python code to determine the external potential can be downloaded from here. A short description of the python code can be found here