NED-D: A Master List of Redshift-Independent Extragalactic Distances
(Version 14.2.0 October 2017)
As compiled by Ian Steer, Barry F. Madore,
and the NED Team
NASA/IPAC Extragalactic Database (NED)
California Institute of Technology
Carnegie Institution of Washington
With additional generous support from the Carnegie Institution of Canada
NED-D data files:
NED-D is an online compilation of redshift-independent extragalactic
distances found in an extensive search of the recently published
literature. Version 14.2.0 (October 2017) of NED-D provides
62970 distances to 7143 galaxies based on primary methods,
using standard candles such as Cepheids and Type Ia supernova, or standard
rulers such as globular cluster radii and masers. Also provided are 205127
distances for 141244 galaxies based on secondary methods (the Tully-Fisher
or Fundamental Plane relations, etc.). In total, NED-D V14.2.0 provides
268100 redshift-independent extragalactic distances for 147195 galaxies.
Users can access the results of this compilation of distances in two
On the Main Interface to NED the link labeled
Redshift Independent Distances allows one to retrieve distances for
individual galaxies within NED. For the Andromeda galaxy for example,
this request currently returns 398 distances based on 23
redshift-independent methods. Galaxy queries draw from the 255664
distances for 143396 galaxies and systems of galaxies that come from
sources that are both peer-reviewed and incorporated within the main
The Galaxy Distances Tabulation (NED-D)
contains all 268100 distances for all 147195 galaxies available,
including all distances incorporated within NED as above,
as well as distances from some peer-reviewed papers still to be
added to NED, plus distances found in conference proceedings or
preprints not generally found in the main NED database. The format
is CSV (comma-separated variable), appropriate for loading into most
database management systems. Table 1 describes
the structure of this tabular version of NED-D.
In earlier releases of NED-D, each published distance estimate was
attached solely to the host galaxy in which it was measured. From Version
5.1 on we have extended the linkage to apply also to the specific objects
themselves within the host galaxies. Such objects include individual
globular clusters, supernovae, Cepheid, RR Lyrae variables and eclipsing
binaries, etc. One application is that there are now enough distance
estimates to individual objects within certain Local Group galaxies, such
as the LMC and SMC, so as to permit detailed 3-dimensional analysis of the
internal structure of these galaxies.
NED-D is designed to meet the need for an up-to-date and easy-to-use
tabulation of redshift-independent extragalactic distances published in
the precision era, broadly taken to be since 1990 and launch of the NASA
Hubble Space Telescope (HST). NED-D exists to support scientists, space
missions, and ground-based observatories in planning, interpretation, and
publication of research on galaxies, extragalactic distances, and cosmology.
NED-D is being maintained as part of NED core activities, with updated and
upgraded versions being made available on a regular basis.
Table 1: Structure of the tabular version of NED-D
||Exclusion Code: indicates where "" (blank) which of the distances
from the master file are from peer-reviewed sources incorporated
within NED, and are both interactive within NED and available via the
Redshift Independent Distances query, and indicates by the letter "R"
and "N" which are among the distances not yet included in NED but
available in the NED-D tabulation.
||NED "Preferred Object Name" for the host galaxy.
||Distance Modulus expressed in mag.
||Quoted (one-sigma) statistical (random) error on the distance modulus.
||Metric distance (in units of Mpc).
||Distance indicator (method) used; see Table 2 for
explanations of the codes.
||REFCODE for the originating paper publishing the distance.
|Ancillary information of the various methods, such as added corrections, zero points, etc.
||Supernova Name: informs users only when distances are based on Type Ia
Supernova (SNIa), Type II Supernova optical (SNII optical), or Type II
Supernova radio (SNII radio) methods, stating which SN is referenced, easing
interactive comparison between NED-D and the author(s) data, which are most
often presented in SN order whether by date or name, rather than order of
galaxy host position, as given here.
||Redshift: appears only in cases where the distance modulus is published as a
"luminosity distance modulus", as provided mostly for Type Ia supernova (SNIa),
showing the target redshift used to transform each "luminosity distance
modulus" given to the corresponding "metric distance", via m-M(L) = [5
||Hubble constant: appears only in cases where the Hubble constant assumed by the
author(s) differs from the default value of H = 70 km/s/Mpc used here and by the
Supernova Cosmology Project, the Supernova Legacy Survey and others, see for
example Astier et al. (2006), who round down the value of H = 72 km/s/Mpc from the
NASA HST Key Project final results by Freedman et al. (2001).
||Adopted LMC modulus
||LMC zero point: appears only in cases where the zero point assumed by the
author(s) differs from a fiduciary value of 18.50 mag.
||Date (Yr. - 1980)
||Notes distinguishing where necessary relevant measurement data.
Our primary gateway to the astronomical literature is the NASA/SAO
Astrophysics Data System (ADS), described by Kurtz et al. (2000). For
the period Jan. 1980 to the present researched for NED-D so far, more than 10
million papers and other resources are available in ADS. Of these, hundreds of
thousands contain the key word "galaxy". For Version 1 (June 2006) we
were, of necessity, fairly conservative in further narrowing down the
number of papers contained in our focused search. For example, a
restricted keyword search on "galaxy + distance + Cepheids" returned
1,500 papers published from 1990 to 2005 inclusive. Of these we
finally ascertained that 241 articles contained newly published
distances. We next expanded the search to capture several other
significant and widely used distance determination methods, e.g., Type
Ia supernova (SNIa), Surface Brightness Fluctuations (SBF), Tip of the
Red Giant (TRGB), and other standard candle methods. Later searches
further expanded the number of secondary distance indicators. NED-D
currently provides distances based on several dozen different
(See Table 2
for a complete listing.)
Figure 1. Growth in the number of individual redshift-independent distance estimates
(blue), and the galaxies with such estimates (red), is shown for both primary
indicators (thick lines) and secondary indicators (thin lines). Cumulative totals
are shown for the end of each five-year period, except the most recent period which
is current through 2014.
NED-D Historical Distances (pre-1930)
We have also collected, using similar procedures,
290 distances to galaxies published
before 1930. One of us (I.S.) has provided a
brief introduction to
Hubble Tuning Fork Shown to Scale Using Distances from NED-D
Click on the image below for details.
- Astier, P. et al. 2006, Astron. & Astrophys., 447, 31
- Freedman, W. L. et al. 2001, Astrophys. J., 553, 47
- Kurtz, M. J. et al. 2000, Astron. & Astrophys. Suppl. 143, 41