The Extragalactic Distance Database (EDD)

The catalog "EDD Distances" gives updated best distances for galaxies within 3,000 km/s.

The first group of catalogs are based on redshift surveys and provide general information about galaxies in the local volume. The "2MASS Redshift Survey" and the "V8k" (velocity < 8,000 km/s) catalog provide alternative descriptions of the large scale structure in the region of interest. The latter is a compilation of redshifts drawn from CfA ZCAT and other literature sources. The figure shows the distribution of the galaxies in V8k in Supergalactic coordinates. Colors indicated velocities as defined by the scale at lower left. The apex of the Cosmic Microwave Background is identified.

The subsequent catalogs are alternatively drawn from the literature or compiled by the curators of this database; each provides some element of information useful for the determination of distances to galaxies. The database contains original contributions of data, or independent reductions of archival data, in the catalogs "CMDs/TRGB", "All Digital HI", and "Hawaii Photometry".

The catalog "CMDs/TRGB" provides Color-Magnitude Diagrams (CMD), photometry tables, and Tip of the Red Giant Branch (TRGB) fits for galaxies observed with Hubble Space Telescope, either by the curators or by others and with data drawn from the HST archive. Reductions are carried out using the stellar photometry packages developed by Andrew Dolphin: HSTPHOT for WFPC2 images and DOLPHOT for ACS images. TRGB fits are based on a maximum likelihood procedure discussed by Makarov et al. 2006. TRGB zero point issues were discussed by Rizzi et al. 2007. The CMD for Antlia dwarf galaxy is shown as an example. The contents of this catalog are described by B.A. Jacobs, L. Rizzi, R.B. Tully, E.J. Shaya, D. Makarov, and L. Makarova 2009, AJ, 138, 332 `The Extragalactic Distance Database: Color--Magnitude Diagrams'

The catalog "All Digital HI" provides graphical displays and derivatives from a uniform analysis of digital HI linewidth information drawing on our own observations with the Green Bank and Arecibo telescopes and much more information gathered from archives. An example is shown of an HI line profile observed with the Green Bank Telescope. This component of the database is described by H.M. Courtois, R.B. Tully, J.R. Fisher, N. Bonhomme, M. Zavodny, and A. Barnes 2009, AJ, 138, 1938 `The Extragalactic Distance Database: All Digital HI Profile Catalog'

The catalog "Hawaii Photometry" provides graphic and derivative results from a program of galaxy photometry carried out with the University of Hawaii 2.2m telescope at Mauna Kea Observatory. The I band surface brightness as a function of radius is shown for the galaxy corresponding to the HI profile illustrated above. The photometry program is discussed by H.M. Courtois, R.B. Tully, N. Bonhomme, L. Rizzi, and M. Zavodny (2009) `The Extragalactic Distance Database: Hawaii Photometry Catalog' [draft].


The HI and photometry information is used to derive distances based on the correlation between galaxy luminosity and linewidth (the Tully-Fisher Relation). The most recent calibration, comparison to assure that distances by different methods are on a common scale, and a current synthesis of distances by several methods is given in the catalog "Cosmicflows-1 Distances" and discussed by R.B. Tully, E.J. Shaya, I.D. Karachentsev, H.M. Courtois, D.D. Kocevski, L. Rizzi, and A. Peel ApJ, 676, 184 (2008). The figure below on the left is extracted and modified from this reference. It illustrates the components of our motion that arise from the pull of the Virgo Cluster and a push from the Local Void. The figure on the right is a velocity field reconstruction using the Monge-Ampere-Kantorovich (MAK) technique applied to the 2MASS Redshift Survey Ks<11.25 sample and constrained with observed distances (G. Lavaux, R.B. Tully, R. Mohayaee, and S. Colombi ApJ, 709, 483, 2010).

An important feature of EDD is the ability to link between catalogs. Each galaxy in every catalog is identified by its `Principal Galaxies Catalog' (PGC) number in the Lyon Extragalactic Database (LEDA). Information for a given galaxy is matched across catalogs through the PGC identifier. One can form joined tables by selecting desired columns from multiple catalogs on the first page. The `submit' button queries the database and the result page has a single joined table. On the result page, the user can cull by minimum and maximum values or temporarily hide columns.

Support for the development of content for this database is provided by the National Science Foundation under Grant No. AST09-08846.