Allsky Images of the XSC

The 2MASS Extended Source Catalog (XSC) is primarily composed of galaxies, and secondarily of Milky Way objects. Galaxies are detected all across the sky except for regions of the Galactic Plane that are opaque with stars (e.g., Galactic Center in Sagitarrius). Galaxies concentrate on several spatial scales, including groups, clusters, and large filamentary superclusters. Milky Way objects are almost exclusively confined to the Galactic Plane, |b| < 3 degrees. The following images show the local Universe as traced by the XSC.

XSC Equatorial Projection

Charts & Maps

2MASS Extended Source Catalog (XSC) Aitoff equal-area projection (w/ 18' pixels) of the integrated XSC flux for Ks < 14.0 mag (1.7 mJy). The near-Infrared J, H, and Ks-bands have been RGB combined to form a color image of the Local Universe. The image orientation is equatorial centered on 6hr right ascension (roughly corresponding to the Galactic anti-center); see the equatorial coordinate map. The "red" sources defining the Galactic Plane are mostly Milky Way in origin, both heavily dust reddened as well as being intrinsically red (due to strong emission lines in the Ks-band window). The Galactic anti-center region (center of image) is also graced by the Orion and Taurus molecular cloud systems (Orion located just right and down from the center of the image, Taurus just right and up from the center). The filaments and coherent structures throughout the image are extragalactic super structures.

2MASS View of the Local Universe: Chart showing the equatorial orientation and location of Large Scale Structure in the local Universe. The image can be directly compared with the Martha Haynes (Cornell U.) redshift survey images. Here for example is the sky distribution for galaxies with a redshift < 12,000 km/s (z < 0.04): Redshift Distribution of Galaxies.

XSC + PSC Equatorial Projection

2MASS Local Universe: XSC + PSC See The Combined XSC and PSC Allsky Images for more details.

Ks-band Differentiated Equatorial Projection

2.2-Micron Differentiated View of the Local Universe. Ks-band integrated flux, separated into three (RGB) mag bins: (1) Ks < 11.5 mag, (2) 11.5 < Ks < 12.75, and (3) 12.75 < Ks < 13.5 mag. The first bin represents the brightest and therefore nearest objects (e.g., Local Group), assigned to the blue (B) channel. The second bin represents the realm of the nearby superclusters (e.g., Coma cluster), assigned to the green (G) channel. The third bin represents the most distant XSC objects, filling in the Universe out to a redshift of 0.2 to 0.3, assigned to the red (R) channel. The image has been convolved with a gaussian filter for additional smoothing. The Milky Way (2MASS Point Source Catalog) is shown with a blue tint, is seen bisecting the local Universe. See the LSS chart for image orientation and Large Scale Structure map.

XSC + PSC SuperGalactic Projection

SG Charts & Maps

SuperGalactic View of the Local Universe. As seen in the 2MASS near-infrared bands: J (1.2-micron), H (1.6-micron) and Ks (2.2-micron), down to 14th mag in Ks. The All Sky image is composed of sources comprising the 2MASS Extended Source Catalog (XSC) -- more than 1.6 million galaxies, and the Point Source Catalog (PSC) -- nearly 0.5 billion Milky Way stars (here shown with a blue tint to contrast with the background galaxies.) The map is projected with an equal area aitoff in the SuperGalactic system (representing the plane of the Local Supercluster, including the Virgo-Coma supercluster of galaxies.) The plane of the Milky Way runs vertically across the image, with the Galactic Center to the upper right.

Supergalactic chart that identifies clusters and large-scale structures

Ks-band Differentiated SuperGalactic Projection	Smoothed SuperGalactic Map
SuperGalactic View of the Ks-band Differentiated Universe. The All Sky image is composed of sources comprising the 2MASS Extended Source Catalog (XSC) -- more than 1.6 million galaxies, and the Point Source Catalog (PSC) -- nearly 0.5 billion Milky Way stars (here shown with a blue tint to contrast with the background galaxies.) The galaxies are color coded in accordance with the Ks band (2.2-micron): (blue are the brightest sources, green moderately bright and red are the faintest sources, extending to Ks=13.5 mag). The map is projected with an equal area aitoff in the SuperGalactic system (representing the plane of the Local Supercluster, including the Virgo-Coma supercluster of galaxies.) The plane of the Milky Way runs vertically across the image, with the Galactic Center to the upper right.	Smoothed Supergalactic Map showing the cosmic web of galaxies. The image was constructed by Chris Dlugosz by aggressive smoothing of the APOD version of the 2MASS Universe.

Ks-band Differentiated SuperGalactic Projection

NED Redshift Distribution

2MASS All Sky Redshift Distribution

2MASS XSC - NED Redshift Distribution. Galatic view of 2MASS XSC galaxies with catalogued redshifts. A total of 70K galaxies with redshifts and Ks brighter than 13.5 mag are found in NED. The bulk of which is comprised of large redshift surveys (e.g., RC3, UGC, 2DF, SDSS), non-uniformly distributed across the sky. The image is constructed using a Galactic projection with the Milky Way front and center. The pixels represent the integrated Ks-band flux of galaxies along the Galactic line of sight, where the flux is divided between the blue, green and red channels based on the redshift, as follows: The redshift is indexed with color, where blue corresponds to the nearest galaxies (z < 0.02), green at moderate distances (0.02 < z < 0.04) and red the most distant galaxies (z > 0.04), and linear RGB combination for transitions between these redshift zones.

2MASS XSC All Sky "Redshift" Distribution. 3-Dimensional view of the 2MASS XSC galaxy distribution in the local Universe. The image shows the galaxies as seen in a Galactic projection with the Milky Way front and center. Distance is represented by the color, where a "redshift" is deduced for each galaxy based on the Ks-band flux (assuming L* properties) or the actual redshift is used if it exits in NED. Roughly 70K sources, or 4% of the total XSC galaxies have measured redshifts. The pixels represent the integrated Ks-band flux of galaxies along the Galactic line of sight, where the flux is divided between the blue, green and red channels based on the "redshift", as follows: The redshift is indexed with color, where blue corresponds to the nearest galaxies (z < 0.02), green at moderate distances (0.02 < z < 0.04) and red the most distant galaxies (z > 0.04), and linear RGB combination for transitions between these redshift zones. Details: K-correction derived from XSC-NED distribution M* is set to -24.0 mag (Schecter Function) to match to the XSC-NED redshift distribution distance modulus: K-Mk = 5logD-5 - K-correction - Av Hubble constant = 72 km/s/Mpc The redshift (Vh/c) is deduced from the integrated Ks-band flux (via distance modulus) corrected for band shifting (K-correction) and Galactic extinction.

2MASS Universe

Chart of the Local Universe

2MASS Universe 3-Dimensional view of the local Universe. The image shows the structure of the Universe at progressively larger distance (redshift) cuts, starting with the Milky Way (z = 0), passing through the Local Supercluster (Z < 0.01) and outward to the most distant galaxies that are clearly resolved by 2MASS. Distance is represented by the color, where a "redshift" is deduced for each galaxy based on the Ks-band flux (assuming L* properties) or the actual redshift if it exits in NED. Roughly 100K sources, or 8% of the total XSC galaxies have measured redshifts. The pixels represent the integrated Ks-band flux of sources along the Galactic line of sight, color-coded by their redshift: where blue corresponds to the nearest galaxies (z < 0.02), green at moderate distances (0.02 < z < 0.04) and red the most distant galaxies. An alternative version of this image (which includes chart & logos) is given here. Click on the following link to see an animated version of the 2MASS Redshift Universe.

Galactic View of the Local Universe: Chart showing the Galactic orientation and location of Large Scale Structure in the local Universe.