6 research outputs found
The 2MASS Redshift Survey - Description and Data Release
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 Ks <=
13.5 mag and is essentially complete and mostly unaffected by interstellar
extinction and stellar confusion down to a galactic latitude of |b|=5 deg 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 Ks =5
deg (>= 8 deg 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 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 Ks = 10 deg.Comment: Accepted for publication in The Astrophysical Journal Supplement
Series. The 2MRS catalogs and a version of the paper with higher-resolution
figures can be found at http://tdc-www.harvard.edu/2mrs
2MTF V. Cosmography, Beta, and the residual bulk flow
Using the Tully-Fisher relation, we derive peculiar velocities for the 2MASS
Tully-Fisher Survey and describe the velocity field of the nearby Universe. We
use adaptive kernel smoothing to map the velocity field, and compare it to
reconstructions based on the redshift space galaxy distributions of the 2MASS
Redshift Survey (2MRS) and the IRAS Point Source Catalog Redshift Survey
(PSCz). With a standard minimization fit to the models, we find that
the PSCz model provides a better fit to the 2MTF velocity field data than does
the 2MRS model, and provides a value of in greater agreement with
literature values. However, when we subtract away the monopole deviation in the
velocity zeropoint between data and model, the 2MRS model also produces a value
of in agreement with literature values. We also calculate the `residual
bulk flow': the component of the bulk flow not accounted for by the models.
This is km/s when performing the standard fit, but drops to km/s for both models when the aforementioned monopole offset between data
and models is removed. This smaller number is more in line with theoretical
expectations, and suggests that the models largely account for the major
structures in the nearby Universe responsible for the bulk velocity.Comment: 16 pages, 9 figures, 2 tables, accepted for publication in MNRA
2MTF â V. Cosmography, β, and the residual bulk flow
Using the Tully-Fisher relation, we derive peculiar velocities for the 2MASS
Tully-Fisher Survey and describe the velocity field of the nearby Universe. We
use adaptive kernel smoothing to map the velocity field, and compare it to
reconstructions based on the redshift space galaxy distributions of the 2MASS
Redshift Survey (2MRS) and the IRAS Point Source Catalog Redshift Survey
(PSCz). With a standard minimization fit to the models, we find that
the PSCz model provides a better fit to the 2MTF velocity field data than does
the 2MRS model, and provides a value of in greater agreement with
literature values. However, when we subtract away the monopole deviation in the
velocity zeropoint between data and model, the 2MRS model also produces a value
of in agreement with literature values. We also calculate the `residual
bulk flow': the component of the bulk flow not accounted for by the models.
This is km/s when performing the standard fit, but drops to km/s for both models when the aforementioned monopole offset between data
and models is removed. This smaller number is more in line with theoretical
expectations, and suggests that the models largely account for the major
structures in the nearby Universe responsible for the bulk velocity.Comment: 16 pages, 9 figures, 2 tables, accepted for publication in MNRA