2MASS Redshift Survey

2MASS Redshift Survey
Name	2MASS Redshift Survey
Acronym	2MRS
Mission type	Astronomical redshift survey
Operator	Two Micron All-Sky Survey
Instruments	1.3 m telescopes, spectrographs
Wavelength	Near-infrared (J, H, K_s)
Start date	1997
Completion date	2011
Objective	Redshift mapping of near-infrared selected galaxies

2MASS Redshift Survey The 2MASS Redshift Survey was a near-infrared spectroscopic follow-up to the Two Micron All-Sky Survey that measured redshifts for a large, all-sky sample of bright galaxies. It linked photometry from the Two Micron All-Sky Survey with spectroscopic campaigns at multiple observatories to produce a uniform redshift catalog used by researchers working on galaxy clustering, peculiar velocities, and the cosmic flow. The project interfaced with international facilities and collaborations and fed into analyses by teams connected to major surveys and theoretical programs.

Overview

The survey built on the Two Micron All-Sky Survey photometric database and drew observer support from facilities including the Fred Lawrence Whipple Observatory, Cerro Tololo Inter-American Observatory, Kitt Peak National Observatory, Anglo-Australian Telescope, and Palomar Observatory. Its target selection emphasized bright near-infrared galaxies identified in the Two Micron All-Sky Survey catalogs, enabling cross-comparisons with optical campaigns such as the Sloan Digital Sky Survey, the 6dF Galaxy Survey, and the IRAS Point Source Catalog Redshift Survey. Leadership and contributors included researchers affiliated with institutions such as Harvard–Smithsonian Center for Astrophysics, National Optical Astronomy Observatory, University of Massachusetts Amherst, and the Jet Propulsion Laboratory.

Survey Design and Methodology

The survey employed near-infrared selection using the J-band, H-band, and Ks-band photometry from the Two Micron All-Sky Survey to mitigate extinction effects near the Zone of Avoidance and to provide mass-weighted sampling complementary to optical luminosity-limited programs like the CfA Redshift Survey and the 2dF Galaxy Redshift Survey. Spectroscopic redshifts were obtained with medium-resolution spectrographs on multiple telescopes including instruments associated with Mount Hopkins, Cerro Tololo, and Kitt Peak, and reduction pipelines were developed drawing on algorithms used by teams from NOAO and AAO. Target selection criteria referenced magnitude limits and completeness thresholds similar to methods used in the Las Campanas Redshift Survey and the Two-degree Field Galaxy Redshift Survey, with observing strategies coordinated to maximize overlap with existing catalogs such as the Principal Galaxy Catalogue and the Updated Zwicky Catalog.

Data Products and Catalogs

The primary deliverable was a redshift catalog combining 2MASS photometry and measured recessional velocities, often cross-indexed with external databases like NASA/IPAC Extragalactic Database and the SIMBAD astronomical database. Catalog entries provided sky positions, near-infrared magnitudes, heliocentric redshifts, and quality flags analogous to entries in the Third Reference Catalogue of Bright Galaxies and formats compatible with data services at Vizier and the Astrophysics Data System. Ancillary products included compiled lists for peculiar velocity studies and group catalogs comparable to those produced by the Galaxy And Mass Assembly project and the Redshift Survey of the Southern Sky.

Scientific Results and Applications

Analyses using the catalog addressed local large-scale structure including mapping the Great Attractor, evaluating contributions to the Cosmic Microwave Background dipole, and constraining flow fields examined in studies linked to the Local Group, the Virgo Cluster, and the Shapley Supercluster. Researchers used the data to derive galaxy density fields and to compare mass tracers from near-infrared selection with optical and far-infrared tracers from surveys such as IRAS and WISE, informing work on biasing models related to submissions by teams from Caltech, Princeton University, and University of Cambridge. The catalog enabled measurements of the correlation function and power spectrum that were compared with predictions from Lambda-CDM simulations performed by groups using codes like GADGET and informed constraints used in analyses by collaborations including those tied to the Planck and WMAP missions.

Limitations and Systematic Uncertainties

Limitations included incompleteness in regions of high extinction near the Galactic Center despite near-infrared selection, fiber and slit allocation constraints similar to those encountered by the Sloan Digital Sky Survey and 2dF projects, and heterogeneous spectrograph resolutions across contributing observatories. Systematic uncertainties arose from photometric calibration subtleties between different 2MASS data releases, redshift zero-point offsets compared against standards used by the CfA Redshift Survey and systematic velocity errors impacting peculiar velocity inferences relevant to analyses by teams at University of Chicago and Max Planck Institute for Astrophysics. Sample variance on the largest scales meant comparisons with numerical predictions from groups at Lawrence Berkeley National Laboratory and Institute for Advanced Study required careful treatment.

Legacy and Impact on Cosmology and Large-Scale Structure

The survey legacy includes a widely used, near-infrared-selected redshift reference that complemented optical and far-infrared redshift surveys, influencing studies by collaborations associated with Planck, WMAP, the Sloan Digital Sky Survey, and the Dark Energy Survey. It provided inputs for reconstruction of the local density and velocity fields used in investigations by researchers at University of Toronto, Yale University, and Imperial College London, and remains a foundational dataset for cross-matched studies with missions like Spitzer Space Telescope, WISE, and future facilities including Euclid and the Nancy Grace Roman Space Telescope. The catalog’s integration into services such as Vizier and the NASA/IPAC Extragalactic Database ensures continuing utility for observational programs and cosmological analyses.

Category:Astronomical surveys