The Indus supercluster

A survey of rich galaxy clusters, redshifts for many of those clusters, and galaxy counts by eye to B = 19.0 show the Indus Supercluster to be an annular (in projection) configuration of nine rich clusters at 0.073 < z < 0.080 apparently connected by bridges of galaxies.Photoelectrically calibrated photographic photometry of galaxy images on six U.K. Schmidt plates using the COSMOS machine at the Royal Observatory, Edinburgh, gave photometric information for about 150,000 galaxies. From this, the luminosity function of the Indus Supercluster was extracted. To B = 21.5, the Supercluster includes about 25,000 galaxies, its estimated total luminosity is 7 x10¹³ L₀, and - if its mass-to-light ratio is typical - its total mass is 1 x 10¹⁶M. Its diameter is about 40 Mpc. These parameters make it similar to other known superclusters.In addition, the integrated apparent field luminosity function for galaxies, derived from the 140 square degrees of sky scanned on Schmidt plates by COSMOS, agrees with most previous determinations.The general picture of a sponge -like cellular distribution of galaxies as developed by Einasto and his colleagues is confirmed. Though there are some indications that this structure is primordial, neither data nor theories are yet sufficient to allow an adequate explanation of the development of such structure in the universe

Redshift-independent Distances in the NASA/IPAC Extragalactic Database: Methodology, Content, and Use of NED-D

Estimates of galaxy distances based on indicators that are independent of cosmological redshift are fundamental to astrophysics. Researchers use them to establish the extragalactic distance scale, to underpin estimates of the Hubble constant, and to study peculiar velocities induced by gravitational attractions that perturb the motions of galaxies with respect to the "Hubble flow" of universal expansion. In 2006 the NASA/IPAC Extragalactic Database (NED) began making available a comprehensive compilation of redshift-independent extragalactic distance estimates. A decade later, this compendium of distances (NED-D) now contains more than 100,000 individual estimates based on primary and secondary indicators, available for more than 28,000 galaxies, and compiled from over 2000 references in the refereed astronomical literature. This paper describes the methodology, content, and use of NED-D, and addresses challenges to be overcome in compiling such distances. Currently, 75 different distance indicators are in use. We include a figure that facilitates comparison of the indicators with significant numbers of estimates in terms of the minimum, 25th percentile, median, 75th percentile, and maximum distances spanned. Brief descriptions of the indicators, including examples of their use in the database, are given in an appendix

Redshift-independent Distances in the NASA/IPAC Extragalactic Database: Methodology, Content, and Use of NED-D

Estimates of galaxy distances based on indicators that are independent of cosmological redshift are fundamental to astrophysics. Researchers use them to establish the extragalactic distance scale, to underpin estimates of the Hubble constant, and to study peculiar velocities induced by gravitational attractions that perturb the motions of galaxies with respect to the "Hubble flow" of universal expansion. In 2006 the NASA/IPAC Extragalactic Database (NED) began making available a comprehensive compilation of redshift-independent extragalactic distance estimates. A decade later, this compendium of distances (NED-D) now contains more than 100,000 individual estimates based on primary and secondary indicators, available for more than 28,000 galaxies, and compiled from over 2000 references in the refereed astronomical literature. This paper describes the methodology, content, and use of NED-D, and addresses challenges to be overcome in compiling such distances. Currently, 75 different distance indicators are in use. We include a figure that facilitates comparison of the indicators with significant numbers of estimates in terms of the minimum, 25th percentile, median, 75th percentile, and maximum distances spanned. Brief descriptions of the indicators, including examples of their use in the database, are given in an appendix

NED and SIMBAD Conventions for Bibliographic Reference Coding

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