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Hickson Compact Groups of Galaxies (HCG) Individual Galaxies Data

Metadata Updated: September 19, 2025

The HCGGALAXY database table is based on the Hickson Catalog of Compact Groups, and contains data on 463 galaxies in 100 compact groups of galaxies that were identified by a systematic search of the Palomar Observatory Sky Survey red prints. Each group contains four or more galaxies, has an estimated mean surface brightness brighter than 26.0 magnitude per arcsec<sup>2</sup> and satisfies an isolation criterion. Astrometry, photometry, and morphological types, derived from CCD images, are presented for the 463 galaxies. Radial velocities are given for 457 of the 463 galaxies: more than 84% of the galaxies measured have radial velocities that are within 1000 km/s of the group median velocity. Morphological information derived from either an isophotal analysis or from a visual inspection of images is given for 210 of the 463 galaxies. This database table essentially contains the information given in Table 2 of Hickson, P. et al. (1989, ApJS, 70, 687), Table 2 of Hickson, P. et al. (1992, ApJ, 399, 353), and Table 2 of Mendes de Oliveira, C. and Hickson, P. (1994, ApJ, 427, 684). Consequently, the information on the properties of the Hickson Compact Groups as units that is also given in some of these references, e.g., in Table 3 of Hickson, P. et al. (1992, ApJ, 399, 353), is not in the HCGGALXY database table; however, the latter data can be found in the related HEASARC database table HCG. This database table was created by the HEASARC in August, 1999, based on machine-readable tables obtained from the ADC/CDS data centers (<a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/213">CDS catalog VII/213</a>, files galaxies.dat and morpho.dat). The HEASARC added Galactic coordinates and updated the table's metadata in August, 2005. This is a service provided by NASA HEASARC .

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

Downloads & Resources

Dates

Metadata Created Date April 11, 2025
Metadata Updated Date September 19, 2025

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date April 11, 2025
Metadata Updated Date September 19, 2025
Publisher High Energy Astrophysics Science Archive Research Center
Maintainer
Identifier ivo://nasa.heasarc/hcggalaxy
Data Last Modified 2025-09-10
Category Astrophysics
Public Access Level public
Bureau Code 026:00
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id 7fd31e5f-efe6-4842-8a77-fb482c37b93a
Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
Harvest Source Title NASA Data.json
Homepage URL https://heasarc.gsfc.nasa.gov/W3Browse/all/hcggalaxy.html
Program Code 026:000
Source Datajson Identifier True
Source Hash 80b7037059a8e7262ddaa6191796014c87df689c5ef43bad84c54c75e52bcb68
Source Schema Version 1.1

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