The 2MASS Extended Source Catalog

WCSTools Catalogs
The 1,647,599-source Two Micron All Sky Survey (2MASS) Extended Source Catalog was produced by a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, funded by the National Aeronautics and Space Administration and the National Science Foundation. The entire sky was uniformly scanned in three near-infrared bands to detect and characterized point sources brighter than about 1 mJy in each band, with signal-to-noise ratio (SNR) greater than 10, using a pixel size of 2.044. The extended source catalog includes those sources which are resolved with respect to the observed 2MASS point spread function. Approximately 97% of XSC sources are galaxies, with the other ~3% belonging to the Milky Way.

The files released by IPAC must be processed before WCSTools can access them. Although IPAC suggests that they be ingested into a relational database manager, WCSTools can access the catalog after it is processed by the simple process described here.

2MASS used two highly-automated 1.3-m telescopes, one at Mt. Hopkins, AZ, and one at CTIO, Chile. Each telescope is equipped with a three-channel camera, each channel consisting of a 256W256 array of HgCdTe detectors, capable of observing the sky simultaneously at J (1.25 5m), H (1.65 5m), and Ks (2.17 5m).

The northern 2MASS facility began routine operations in 1997 June, and the southern facility in 1998 March. The 2MASS Second Incremental Data Release contains Image and Catalog data covering 19,681 square degrees of sky, derived from Survey observations made at the northern 2MASS facility on Mt. Hopkins, AZ, and the southern facility on Cerro Tololo, Chile. The observations in this release were obtained between 1997 June 7 and 1999 May 21 UT at Mt. Hopkins and 1998 March 19 and 1999 February 20 UT at Cerro Tololo.

To enable rapid access of specific stars in the catalog, WCSTools software numbers each star using an RA region number (0000-2330) and a seven-digit star number within each region, separated by a decimal point. stmx lists 2MASS extended sources by number or sky region. imtmx lists the 2MASS extended sources within an IRAF or FITS image with a world coordinate system defined in its header.

2MASS Extended Source Catalog Format

(All-Sky Data Release)

Extended Source Catalog
Explanatory Supplement

(All-Sky Data Release)

2MASS Explanatory Supplement

(All-Sky Data Release)


(All-Sky Data Release)

[2MASS Point Source Catalog] [WCSTools stmx] [WCSTools imtmx]