Astronomy:HCG 87
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Short description: Galaxy cluster in the constellation Capricornus
| HCG 87 | |
|---|---|
 Galaxy Group HCG 87 | |
| Observation data (Epoch ) | |
| Constellation(s) | Capricornus |
| Right ascension | 20h 48m 11.9ss[1] |
| Declination | −19° 50′ 35″[1] |
| Number of galaxies | ~5 |
| Distance (co-moving) | 400 million |
| Other designations | |
| None | |
HCG 87 is a compact group of galaxies listed in the Hickson Compact Group Catalogue. This group is about 400 million light-years away [2] in the constellation Capricornus. The group distinguishes itself as one of the most compact groups of galaxies, hosting two active galactic nuclei and a starburst among its three members, all of which show signs of interaction.[3] This interaction, which astronomers have called visually, and scientifically, intriguing[4] is being examined to understand the influence of active nuclei on star formation histories.
Members
| Name | Type[5] | R.A. (J2000)[5] | Dec. (J2000)[5] | Redshift (km/s)[5] | Apparent Magnitude[5] |
|---|---|---|---|---|---|
| HCG 87a | S0 pec | 20h 48m 15.0s | −19° 50′ 58″ | 8443 ± 14 | 15.3 |
| HCG 87b | SA(r)0 pec | 20h 48m 10.9s | −19° 51′ 23″ | 8740 ± 20 | 15.4 |
| HCG 87c | Sb | 20h 48m 12.0s | −19° 49′ 56″ | 8914 ± 7 | 16.1 |
| HCG 87d | Sd | 20h 48m 12.8s | −19° 50′ 46″ | 10200 ± 160 | 17.8 |
External links
- Astronomy Picture of the Day
- Galaxy Group HCG 87 – 2003 July 31
- HCG 87: A Small Group of Galaxies – 2010 July 6
- Close-ups of HCG 87
- Galactic Clusters
- Studies of Hickson Compact Groups
References
- ↑ 1.0 1.1 1.2 "NASA/IPAC Extragalactic Database". Results for HCG 87. http://nedwww.ipac.caltech.edu/. Retrieved 2006-10-19.
- ↑ This redshift corresponds to a distance of 120Mpc or 400 million light years (using H0 = 75km/s/Mpc and q0 = 0.1). At the distance of the group, this corresponds to a group diameter of 52kpc, i.e., the group is approximately 170,000 light years across.
- ↑ Noll, Keith. 07/1999. "Hubble Heritage observations of Hickson Compact Galaxy Group 87".
- ↑ English, J. et al. 05/2000. "A Minuet of Galaxies: Hickson Compact Group 87 as Viewed by the Hubble Space Telescope". American Astronomical Society, 195th AAS Meeting, #136.04; Bulletin of the American Astronomical Society, Vol. 32, p.884.
- ↑ 5.0 5.1 5.2 5.3 5.4 "NASA/IPAC Extragalactic Database". Results for various galaxies. http://nedwww.ipac.caltech.edu/. Retrieved 2006-10-19.
Coordinates: 
20h 48m 11.9s, −19° 50′ 35″
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