HCG 3

HCG 3
HCG 3 seen by Legacy Surveys Dr10
Observation data (Epoch J2000)
ConstellationCetus
Right ascension00h 34m 28.8000s
Declination−07° 34′ 58.800″
Number of galaxies4
Velocity dispersion251.2 km/s
Redshift0.026321
Distance363.4 Mly (111.43 Mpc)
Other designations
[DZ2015] 471

HCG 3 is a compact group of galaxies from the Hickson Compact Group catalog. It is located in the Constellation Cetus, less than 1 degree north of NGC 157 and is 111.43 ± 7.81 Mega Parsecs away. Hickson Compact Group 3, along with 99 others, was identified by Paul Hickson in 1982. HCG 3 has a radial velocity dispersion of 251 km/s and the crossing time is = 0.023. In this compact group there are only 3 true members, which are HCG 3A, 3B and 3D. HCG 3C is located in the background.

Properties

Far-Infrared Studies by using the Infrared Astronomical Satellite (IRAS) shows that only HCG 3C emits a strong infrared signal, indicating a high amount of star formation and stellar nurseries. Far-infrared astronomy detects thermal radiation of interstellar dust contained in molecular clouds and nebulas, making it a reliable source to detect for massive amount star formation. Far-Infrared Luminosity of HCG 3C is 10.433 L☉, but for HCG 3A, 3B and 3D, their emission is weak or not detected by the satellite.

is the total brightness of the specific galaxy seen through a blue filter. HCG 3A is the brightest of the four, and HCG 3C is the dimmest of the four as shown in the table. B-R is equivalent to blue minus red, which is used to study star formation in the targeted galaxy. HCG 3C has the lowest B-R, indicating a large amount of molecular cloud formation, while HCG 3B has the highest B-R, representing a high amount of old stellar population.

HCG 3C (PGC 2059 or 2MFGC 400) is considered a Low Surface Brightness galaxy (LSB). In the surrounding field of HCG 3, there are a two galaxies appear in the background or foreground, which are MCG 01-02-035 (Seyfert 2 galaxy) and LEDA 138198 (Emission Line galaxy).

Members

HCG 3 consists of 4 member galaxies. Their details are written below.

HCG Galaxy Type Ra Dec Diameter (") Estimated Distance (Megaparsec) Velocity (km/s) B-R B_T
3A MCG -01-02-032 Sc 00h 34m 13.1990s −07° 33′ 53.554″ 67.50 102.75 7302 1.4100 15.36
3B PGC 2064 SB0a 00h 34m 25.1139s −07° 35′ 58.212″ 56.70 110.98 7860 1.7100 15.64
3C PGC 2059 Sd? 00h 34m 20.0199s −07° 36′ 00.926″ 25.40 165.33 11545 1.3700 16.54
3D PGC 2043 S0 00h 34m 09.8359s −07° 36′ 08.595″ 44.40 110.15 7804 1.6900 15.91

References

  1. ↑ Hickson, P. (1982). "Systematic properties of compact groups of galaxies". Astrophysical Journal. 255: 382. Bibcode:1982ApJ...255..382H. doi:10.1086/159838.
  2. ↑ Hickson, P. (1992). "Dynamical Properties of Compact Groups of Galaxies". Astrophysical Journal. 399: 353. Bibcode:1992ApJ...399..353H. doi:10.1086/171932.
  3. ↑ Verdes-Montenegro, L. (1998). "Effects of Interaction-Induced Activities in Hickson Compact Groups: CO and Far-Infrared Study". Astrophysical Journal. 497: 89. arXiv:astro-ph/9707062. Bibcode:1998ApJ...497...89V. doi:10.1086/305456.
  4. ↑ "2MFGC 400". SIMBAD Astronomical Database. Centre de données astronomiques de Strasbourg. Retrieved 2026-10-16.
  5. ↑ "LEDA 2043 — hierarchy and associated objects". SIMBAD Astronomical Database. Centre de données astronomiques de Strasbourg. Retrieved 2026-10-16. SIMBAD lists 5 siblings for LEDA 2043, reflecting the surrounding field of HCG 3.
  6. ↑ "NED results for HCG 003". NASA/IPAC Extragalactic Database. Retrieved 2026-05-17.
  7. ↑ Hickson, P. (1993). Atlas of Compact Groups of Galaxies. NASA Astrophysics Data System. p. 12. Bibcode:1993ApL&C..29....1H.
  8. 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.
  9. ↑ "NED results for MCG -01-02-032". NASA/IPAC Extragalactic Database. Retrieved 2026-05-17.
  10. ↑ "NED results for WISEA J003425.11-073558.2". NASA/IPAC Extragalactic Database. Retrieved 2026-05-17.
  11. ↑ "NED results for WISEA J003420.01-073600.9". NASA/IPAC Extragalactic Database. Retrieved 2026-05-17.
  12. ↑ "NED results for WISEA J003409.83-073608.5". NASA/IPAC Extragalactic Database. Retrieved 2026-05-17.