VI. Analysis of the 2MASS Second Incremental Release Catalogs
4. Completeness and Reliability
e. Large Galaxies Encountered in the 2MASS
The extended source processor (GALWORKS) attempts to detect, analyze and extract galaxies as large as ~5´ in diameter. A "seed" catalog of known galaxies with diameters larger than 1´ (optical diameters, as given in NED) is part of the GALWORKS operations. Known galaxies in which more than 75% of the object is contained within one Atlas Image are processed accordingly. Objects which do not satisfy this criteria (i.e., they are either too big or they are too close to an edge) are not processed. The following tables list galaxies that were processed and galaxies that were not. Note: the tables are not exclusive to the XSC. They include all scans reduced in the 2MASS pipeline.
i. Large Galaxies Not Processed in 2MASS
Table 1 lists all of the known large
galaxies that were not processed by GALWORKS, due to their size
(as given by the optical diameter) or due to the proximity to a scan edge.
Note: Duplication observations (from different nights) are included.
ii. Large Galaxies Processed in 2MASS
Table 2 lists all of the known large
galaxies that were processed & extracted by GALWORKS. The table
contains about 60,000 sources.
Note: Duplication observations (from different nights) are included.
iii. Method
The tables were not generated from the IRSA database, but instead
from the internal GALWORKS auxillary file "bright###.gals," which is
stored with each scan output from GALWORKS.
[Last Updated: 2000 Feb 2 by T. Jarrett.
Modified 2000 Jul 31 by S. Van Dyk.]
date = date of observation; h = hemisphere; sc# = scan number
ra,dec = J2000 coordinates; dmaj = optical diameter (arcmin)
name = NED name; type = NED morph type
date = date of observation; h = hemisphere; sc# = scan number
ra,dec = J2000 coordinates; dmaj = optical diameter (arcmin)
name = NED name; type = NED morph type
Previous page. Next page.
Return to Explanatory Supplement TOC Page.