We present the results of the 2MASS Redshift Survey (2MRS), a ten-year project to map the full three-dimensional distribution of galaxies in the nearby Universe. The 2 Micron All-Sky Survey (2MASS) was completed in 2003 and its final data products, including an extended source catalog (XSC), are available on-line. The 2MASS XSC contains nearly a million galaxies with K s ≤ 13.5 mag and is essentially complete and mostly unaffected by interstellar extinction and stellar confusion down to a galactic latitude of |b| = 5 • for bright galaxies. Near-infrared wavelengths are sensitive to the old stellar populations that dominate galaxy masses, making 2MASS an excellent starting point to study the distribution of matter in the nearby Universe.We selected a sample of 44,599 2MASS galaxies with K s ≤ 11.75 mag and |b| ≥ 5 • (≥ 8 • towards the Galactic bulge) as the input catalog for our survey. We obtained spectroscopic observations for 11,000 galaxies and used previously-obtained velocities for the remainder of the sample to generate a redshift catalog that is 97.6% complete to well-defined limits and covers 91% of the sky. This provides an unprecedented census of galaxy (baryonic mass) concentrations within 300 Mpc.Earlier versions of our survey have been used in a number of publications that have studied the bulk motion of the Local Group, mapped the density and peculiar velocity fields out to 50 h −1 Mpc, detected galaxy groups, and estimated the values of several cosmological parameters.Additionally, we present morphological types for a nearly-complete sub-sample of 20,860 galaxies with K s ≤ 11.25 mag and |b| ≥ 10 • .

We present the results of applying a percolation algorithm to the initial release of the Two Micron All-Sky Survey Extended Source Catalog, using subsequently measured redshifts for almost all of the galaxies with K < 11.25 mag. This group catalog is based on the first near-IR all-sky flux-limited survey that is complete to |b| = 5 • . We explore the dependence of the clustering on the length and velocity scales involved. The paper describes a group catalog, complete to a limiting redshift of 10 4 km s −1 , created by maximizing the number of groups containing 3 or more members. A second catalog is also presented, created by requiring a minimum density contrast of δρ/ρ ≥ 80 to identify groups. We identify known nearby clusters in the catalogs and contrast the groups identified in the two catalogs. We examine and compare the properties of the determined groups and verify that the results are consistent with the UZC-SSRS2 and northern CfA redshift survey group catalogs. The all-sky nature of the catalog will allow the development of a flow-field model based on the density field inferred from the estimated cluster masses.

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Fig. E1.-Linking parameter as a function of redshift for the density contrasts corresponding to the LDC and HDC catalogs. The original and corrected values are plotted, along with the mean intergalaxy separation. We assume h ¼ 0:73 where a value is required.A computational error resulted in a scaling of the linking parameter, D, with a weaker dependence on redshift than that described in the text. Figure E1 shows linking length D(V ) as a function of redshift, V, in both utilized and corrected forms. The mean intergalaxy separation (of visible galaxies) computed from the luminosity function for a K < 11:25 survey is also shown, for scale.Since the redshift distribution of visible galaxies peaks near 6000 km s À1 , where the difference between the scalings is minimized, the overall properties of the groups are consistent (within reported 99% confidence levels) with the values in the original article. The revised values are given here in the corrected Table 2 ; the conclusions of the article remain unchanged. The change in group identification is most significant very nearby (V P1500 km s À1 ), where the reduced linking length results in fewer groups merging with the Virgo group.The values of D 0 ¼ D (V F ¼ 1000 km s À1 ) should read 1.04 Mpc for the LDC catalog (/ ¼ 12) and 0.56 Mpc for the HDC catalog (/ ¼ 80). The linking parameters obtained when maximizing the number of groups using the corrected algorithm are consistent with those selected for the definition of the LDC catalog. We present the revised LDC and HDC group catalogs, at density contrasts / ¼ 12 (setting V 0 ¼ 399 km s À1 ) and / ¼ 80 (setting V 0 ¼ 350 km s À1 ), respectively. The full corrected catalogs (Tables 6, 7, 10, and 11) are available in electronic form with the online materials accompanying this erratum. We are grateful to Guilhem Lavaux for bringing the error to the attention of the authors.On-line material: machine-readable tables