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Session 55 - New Digital Sky Surveys.
Display session, Wednesday, June 10
The 2 Micron All Sky Survey (2MASS), now underway, will observe somewhere between 1 and 2 million galaxies with high completeness and reliability down to J = 15 and Ks = 13.5 mag. About 0.01% of this catalog will be comprised of galaxies from the Hercules cluster, a large fraction of which was recently acquired by the 2MASS project. As part of a 2MASS engineering and early check-out run the Hercules cluster was observed multiple times to assess photometric repeatibility and completeness amp; reliability. A summary of the repeatibility results and sensitivity limits for 2MASS galaxy photometry is given.
We present the JHKs colors and redshifts for galaxies located toward the Hercules cluster. Our main conclusions for Hercules are that galaxies have a well-defined, restricted location of J-H amp; H-Ks colors, (2) the galaxy color-color plot is quite different from the point source color- color plot, and is consistent with the expected redshift distribution of 2MASS galaxies, (3) the change in galaxy color versus redshift (the K-correction) can be used to obtain statistical redshifts of 2MASS galaxies from the 2MASS galaxy color-color diagram, and (4) except for z greater than 0.3, the similar K-correction for elliptical and spiral galaxies renders limited statistical separation using the 2MASS color-color diagram.
Program listing for Wednesday