Astronomy:NGC 1550 Group
| NGC 1550 Group | |
|---|---|
 NGC 1550 imaged by Pan-STARRS | |
| Observation data (Epoch ) | |
| Constellation(s) | Taurus |
| Right ascension | 04h 15m 27.3s[1] |
| Declination | 02° 41′ 02″[1] |
| Distance (co-moving) | 51.4 ± 2.8 Mpc (168 ± 9 Mly) |
NGC 1550 Group is a galaxy group of at least eight galaxies centred on the lenticular galaxy NGC 1550 in the constellation Taurus. It is notable for being one of the most luminous galaxy groups in X-ray light, notable for its temperature and velocity dispersion, and has been classified as a fossil group.[2]
Discovery and observation
The central galaxy NGC 1550 was discovered by William Herschel in 1785. It was later observed by Heinrich d'Arrest on 29 December 1861 and catalogued as NGC 1551 before they were recognised as the same object.[3] The group itself is sometimes referred to in literature by the name of its dominant member or the associated X-ray source RX J0419+0225.[4]
In 2020, observations from Chandra suggested galaxies in the NGC 1550 Group are heated by active galactic nuclei.[5]
X-ray properties
The intragroup medium (hot gas) has a temperature of 1.37 ± 0.01 keV. Detailed Chandra observations reveal a cooling core in the central regions and an entropy profile that has been used to study nongravitational processes in galaxy groups.[6] The group shows evidence of active galactic nucleus (AGN) feedback and gas sloshing, as revealed by combined Chandra and Giant Metrewave Radio Telescope (GMRT) data, it was previously considered relaxed, but exhibits structures indicating minor mergers or infalling material.[5]
Suzaku observations have mapped the metal abundance distributions out to ~0.5 r180, showing steeper radial gradients for magnesium, silicon, sulfur, and iron, while oxygen is nearly flat. The abundance ratios and supernova type II to type Ia ratio (approximately 2.9 in the inner regions) are consistent with those of other groups and poor clusters.[2] XMM-Newton data support a galaxy-merger scenario in which the metals trace the total mass well, while the stellar component is more centrally concentrated.[4]
Members
The table below lists the eight galaxies in the NGC 1550 Group.[1]
| Name | Class. | Type | α (J2000.0) | δ (J2000.0) | Vitesse radiale (km/s) | m | Distance (Mpc) | Diameter (kal) |
|---|---|---|---|---|---|---|---|---|
| NGC 1542 | Sab | Spiral | Template:Right ascension | Template:Declination | 3705 ± 8 | 13,9[7] | 53,3 ± 3,7 | 94 |
| NGC 1550 | SA0^-(s)? | Lenticular | Template:Right ascension | Template:Declination | 3718 ± 17 | 12,0[7] | 53,6 ± 3,8 | 131[lower-alpha 1] |
| UGC 2994 | SAdm? | Magellanic spiral | Template:Right ascension | Template:Declination | 3319 ± 3 | 14,3 | 47,6 ± 3,3 | 78 |
| UGC 2998 | SB(rs)b | Barred spiral | Template:Right ascension | Template:Declination | 3349 ± 6 | 13,1 | 48,1 ± 3,4 | 79 |
| UGC 3002 | SBcd? | Barred spiral | Template:Right ascension | Template:Declination | 3565 ± 6 | 12,79 | 51,3 ± 3,6 | 60 |
| UGC 3004 | SB? | Barred spiral | Template:Right ascension | Template:Declination | 3571 ± 5 | 13,7 | 51,4 ± 3,6 | 76 |
| UGC 3010[lower-alpha 2] | SBcd? | Barred spiral | Template:Right ascension | 3865 ± 2 | 14,7 | 55,7 ± 3,9 | 62 | |
| PGC 14744 | SB(s)m | Barred magellanic spiral | Template:Right ascension | Template:Declination | 3511 ± 4 | 15,4241 | 50,4 ± 3,5 | 68 |
Notes
- ↑ See the page for this galaxy regarding the value of the diameter
- ↑ The NASA/IPAC Extragalactic Database indicates that UGC 3010 is a field galaxy, which means it does not belong to a cluster or group and is therefore gravitationally isolated.[8]
References
- ↑ 1.0 1.1 1.2 Garcia, A.M. (1993). "General study of group membership. II - Determination of nearby groups". Astronomy and Astrophysics Supplement Series 100 #1: 47-90. Bibcode: 1993A&AS..100...47G.
- ↑ 2.0 2.1 Sato, Kosuke; Kawaharada, Madoka; Nakazawa, Kazuhiro; Matsushita, Kyoko; Ishisaki, Yoshitaka; Yamasaki, Noriko Y.; Ohashi, Takaya (2010-12-25). "Metallicity of the Fossil Group NGC 1550 Observed with Suzaku" (in en). Publications of the Astronomical Society of Japan 62 (6): 1445–1454. doi:10.1093/pasj/62.6.1445. ISSN 2053-051X. https://academic.oup.com/pasj/article/62/6/1445/1503137.
- ↑ "Celestial Atlas Table of Contents, NGC 1550". http://cseligman.com/text/atlas/ngc15a.htm#1550.
- ↑ 4.0 4.1 Kawaharada, Madoka; Makishima, Kazuo; Kitaguchi, Takao; Okuyama, Sho; Nakazawa, Kazuhiro; Matsushita, Kyoko; Fukazawa, Yasushi (2009-02-01). "A Galaxy Merger Scenario for the NGC 1550 Galaxy from Metal Distributions in the X-Ray Emitting Plasma". The Astrophysical Journal 691 (2): 971–983. doi:10.1088/0004-637X/691/2/971. ISSN 0004-637X. Bibcode: 2009ApJ...691..971K. https://iopscience.iop.org/article/10.1088/0004-637X/691/2/971.
- ↑ 5.0 5.1 Kolokythas, Konstantinos; O'Sullivan, Ewan; Giacintucci, Simona; Worral, Diana M; Birkinshaw, Mark; Raychaudhury, Somak; Horellou, Cathy; Intema, Huib et al. (June 2, 2020). "Evidence of AGN feedback and sloshing in the X-ray luminous NGC 1550 galaxy group". Monthly Notices of the Royal Astronomical Society 496 (2): 1471–1487. doi:10.1093/mnras/staa1506. https://academic.oup.com/mnras/article/496/2/1471/5850388?login=false. Retrieved February 19, 2026.
- ↑ Sun, M.; Forman, W.; Vikhlinin, A.; Hornstrup, A.; Jones, C.; Murray, S. S. (2003-11-20). "Chandra Observations of the NGC 1550 Galaxy Group: Implication for the Temperature and Entropy Profiles of 1 keV Galaxy Groups" (in en). The Astrophysical Journal 598 (1): 250–259. doi:10.1086/378887. ISSN 0004-637X. Bibcode: 2003ApJ...598..250S. https://iopscience.iop.org/article/10.1086/378887.
- ↑ 7.0 7.1 "Les données de «Revised NGC and IC Catalog by Wolfgang Steinicke», NGC 1500 à 1599" (in fr). https://astrovalleyfield.com/AstronomieCompl/NGC%20et%20autres/WolfgangS/N1500_exc_web.htm.
- ↑ "UGC 3010" (in en). http://ned.ipac.caltech.edu/cgi-bin/objsearch?objname=UGC+3010&extend=no&hconst=73&omegam=0.27&omegav=0.73&corr_z=1&out_csys=Equatorial&out_equinox=J2000.0&obj_sort=RA+or+Longitude&of=pre_text&zv_breaker=30000.0&list_limit=5&img_stamp=YES.
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