HCG 1

HCG 1
Hickson Compact Group 1 with Legacy Surveys DR10
Observation data (J2000 epoch)
ConstellationAndromeda
Right ascension00h 23m 01.365s
Declination+25° 26′ 47.793″
Redshift0.03397
Distance460 Million light-years
Characteristics
Size2'.9 x 2'.9
Other designations
V1CG 660

HCG 1 is a compact group of galaxies in the Hickson Compact Group catalogue identified using a systematic search by the Palomar Observatory Sky Survey led by Paul Hickson in 1982. This group is composed of four interacting member galaxies, two of which are peculiar.

Properties

A study proves that HCG 1A is the brightest in this group, having an absolute magnitude of 20.6, corrected total blue magnitude () of 14.43 and blue minus red (B-R) 1.29, indicating this galaxy is undergoing vigorous star birth and formation. HCG 1B, 1C and 1D have absolute magnitudes of 20.0, 19.5 and 18.5, suggesting that HCG 1D is in a high chance of being dominated by old, cool and ageing stars. Hickson Compact Group 1 has a crossing time (H0tc) of 0.0479 and a radial velocity dispersion (km/s) of 85.1. This proves that HCG 1 is a stable and moderate evolving group and this group has an environment that is conducive to have frequent gravitational interactions, which affect galaxies morphological shape and may increase star formation in certain interaction areas.

A study shows that HCG 1 have a total of 13 foreground stars, 9 foreground unidentified objects and 10 foreground galaxies. Hickson Compact Group 1 has a total of 2 out of 4 galaxies that are spirals, the spiral fraction is exactly 50% or 0.5.

Another study shows that HCG 1A and 1B has a tidal arm, indicating that they are gravitationally interacting within themselves or with other galaxies.

Members

Hickson Compact Group 1 have 4 members. Their details and information are stated in the table below.

Members of HCG 1
HGC Name Type Mag. Right Ascension Declination Distance Major Axis Diameter Minor Axis Diameter B_TC B−R Redshift Velocity

(km/s)

1a PGC 1627 Sbc? peculiar 15.0 00 26 07.1 +25 43 31 460 Mly 37.60 26.90 14.43 1.29 0.034147 10237
1b PGC 1625 S0/a? peculiar 15.5 00 26 06.0 +25 43 09 460 Mly 42.80 10.70 15.04 1.36 0.034227 10266
1c PGC 1614 E1 15.9 00 25 54.4 +25 43 25 450 Mly 10.70 10.70 15.57 1.69 0.033543 10056
1d PGC 1618 S0 17.4 00 25 58.8 +25 43 31 455 Mly 8.50 4.80 16.50 1.60 0.033757 10120

References

  1. ↑ Hickson, P. (1982). "Systematic properties of compact groups of galaxies". The Astrophysical Journal. 255: 382. doi:10.1086/159838. ISSN 0004-637X.
  2. 1 2 "Hickson's Compact Groups (HCG) of Galaxies". cseligman.com. Retrieved 2026-04-26.
  3. ↑ Mendes de Oliveira, C.; Hickson, P. (1991). "The Luminosity Function of Compact Groups of Galaxies". The Astrophysical Journal. 380: 30. Bibcode:1991ApJ...380...30M. doi:10.1086/170564.
  4. 1 2 Hickson, P. (1993). "Atlas of Compact Groups of Galaxies". Astrophysical Letters and Communications. 29: 1. Bibcode:1993ApL&C..29....1H.
  5. 1 2 3 4 Kindl, Enrico (1991). A photometric and morphological study of compact groups of galaxies and their environments (Ph.D. thesis). University of British Columbia.
  6. ↑ Mendes de Oliveira, C.; Hickson, P. (1994). "Morphology of Galaxies in Compact Groups". The Astrophysical Journal. 427: 684. arXiv:astro-ph/9311065. Bibcode:1994ApJ...427..684M. doi:10.1086/174176.
  7. 1 2 Hickson, P.; Kindl, E.; Auman, J. R. (1989). "A photometric catalog of compact groups of galaxies". The Astrophysical Journal Supplement Series. 70: 687. Bibcode:1989ApJS...70..687H. doi:10.1086/191354.
  8. ↑ Hickson, P.; Mendes de Oliveira, C.; Huchra, J. P.; Palumbo, G. G. C. (1992). "Dynamical Properties of Compact Groups of Galaxies". The Astrophysical Journal. 399: 353. Bibcode:1992ApJ...399..353H. doi:10.1086/171932.
  9. ↑ "NED results for HCG 1a". NASA/IPAC Extragalactic Database. National Aeronautics and Space Administration / Infrared Processing and Analysis Center. Retrieved 2026-07-17.
  10. ↑ "NED results for HCG 1b". NASA/IPAC Extragalactic Database. National Aeronautics and Space Administration / Infrared Processing and Analysis Center. Retrieved 2026-07-17.
  11. ↑ "NED results for HCG 1c". NASA/IPAC Extragalactic Database. National Aeronautics and Space Administration / Infrared Processing and Analysis Center. Retrieved 2026-07-17.
  12. ↑ "NED results for HCG 1d". NASA/IPAC Extragalactic Database. National Aeronautics and Space Administration / Infrared Processing and Analysis Center. Retrieved 2026-07-17.