HCG 3
Compact group of galaxies
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 H₀tc = 0.023.
01Properties
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 10.433L☉, but for HCG 3A, 3B and 3D, their emission is weak or not detected by the satellite.
B_T 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.
02Members
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 |
Sources and credits
This article is adapted from the Wikipedia article “HCG 3”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- HCG 3 legacy dr10.jpg by Legacy Surveys / D.Lang (Perimeter Institute) & Meli thev, CC BY-SA 4.0
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