Fornax Cluster Explained

Fornax Cluster should not be confused with Furneaux Group.

The Fornax Cluster is a cluster of galaxies lying at a distance of 19 megaparsecs (62 million light-years).^[1] It has an estimated mass of solar masses,^[2] making it the second richest galaxy cluster within 100 million light-years, after the considerably larger Virgo Cluster. It may be associated with the nearby Eridanus Group. It lies primarily in the constellation Fornax, with its southern boundaries partially crossing into the constellation of Eridanus, and covers an area of sky about 6° across or about 28 sq degrees.

The Fornax Cluster is a particularly valuable source of information about the evolution of such clusters due to its relatively close proximity to the Sun. It also shows the gravitational effects of a merger of a galaxy subgroup with the main galaxy group,^[3] which in turn lends clues about the associated galactic superstructure.^[4] At the centre of the cluster lies NGC 1399. Other cluster members include NGC 1316 (the group's brightest galaxy), NGC 1365, NGC 1427A, NGC 1427 and NGC 1404.

Structure

Fornax can be divided into two subclusters: the main cluster, centered on NGC 1399, and a subgroup 3 degrees to the southwest centered on the lenticular galaxy NGC 1316 that is currently in the process of infalling with the largest subcluster to merge with it, and whose galaxies are experiencing relatively strong star formation activity. ^[5]

Intracluster medium

As with many other galaxy clusters, Fornax intracluster medium is filled with a hot, rarefied gas that emits X-rays.^[6] and contains a number of intergalactic stars, some of which have produced novae.^[7]

List of cluster members

Designation! colspan="2"

Coordinates (Epoch 2000)		Type	Mean Angular diameter (arcminutes)	Diameter (x1000 Light-years)	Distance (mly)	Recessional velocity (km/s)
Right Ascension							Declination
ESO 357-07	03 10.4	−33 09	14.7	SBm	2.2	40		981
ESO 357-12	03 16.9	−35 32	14.8	SBcd	2.2	40		1445
	03 19.6	−32 28	14.5	SBb	2.1	40	67	1318
	03 21.1	−37 06	13	SBc	1.9	35	64	1640
	03 22.1	−37 35	?	Irr	2.9	55		1507
	03 22.7	−37 12	9.4	(R')SAB(s)0	11.5	215	62	1664
	03 22.7	−37 06	11.9	SBa	3.0	55	70	1935
	03 23.9	−36 28	11.5	S0	4.3	80	63	1247
NGC 1326A	03 25.1	−36 22	14.7	SBm	1.7	30	84	1719
NGC 1326B	03 25.3	−36 23	13.7	SBm	3.5	65	46	888
	03 26.0	−32 54	13.9	E	1.6	30	61	1158
	03 26.5	−35 43	13.4	E	1.9	35	65	1360
	03 28.0	−37 09	13.3	SBab	1.6	30	86	1760
	03 28.1	−32 17	12.8	E	1.9	35	64	1240
	03 28.3	−31 04	11.2	E	5.6	105	60	1052
	03 28.8	−35 11	14.2	SBbc	2.3	45		1241
ESO 358-10	03 29.7	−33 33	14.8	E	1.5	30		1620
	03 30.6	−34 51	12.4	E-S0	3.2	60	69	1420
NGC 1350	03 31.1	−33 38	11.2	Sa(r)	5.8	130	87	1905
	03 33.6	−36 08	10.3	(R')SBb(s)b	11.0	205	56	1636
	03 33.9	−31 12	13.1	S0	1.9	35	56	1137
	03 35.3	−35 14	11.0	E	2.7	50	59	1240
NGC 1375	03 35.3	−35 16	12.2	SB0 pec	2.1	23	28	643
	03 35.5	−34 27	13.4	S0	2.3	45	60	1530
	03 36.1	−35 26	11.9	E	2.6	50	60	1264
	03 36.5	−34 59	9.9	S0	4.8	85	60	1737
	03 36.5	−35 18	11.5	S0	2.6	55	60	1673
	03 36.8	−36 15	13.6	Sa	1.7	30	65	1340
	03 36.8	−36 00	11.2	(R)SA(r)0/a	3.4	65	53	868
	03 36.8	−34 44	13.4	S0	2.5	45	72	1419
	03 37.0	−35 30	10.8	(R')SAB(s)0	3.2	60	53	1296
	03 37.1	−35 12	13.8	E	1.5	30	80	1697
	03 37.2	−35 45	12.6	E	2.6	50	42	883
	03 38.6	−35 27	13.8	E	0.7	7	67	853
	03 38.5	−35 26	9.9	E	6.8	130	66	1335
	03 38.9	−35 36	10.9	E	4.1	75	65	1942
	03 39.4	−31 19	12.9	SBbc	3.9	75	50	963
	03 40.1	−35 38	13.4	Irr	2.1	40	52	2028
ESO 358-50	03 41.1	−33 47	13.9	S0	1.6	30		1151
ESO 358-51	03 41.5	−34 53	14.1	Sa	1.5	30		1626
	03 42.2	−29 54	11.4	SA(rs)b	6.0	115	69	1402
	03 42.3	−35 24	11.8	E	3.6	70	71	1327
	03 42.4	−35 09	14.0	E	1.5	30	75	1602
NGC 1437A	03 43.0	−36 16	14.2	SBd	1.7	30	41	798
	03 43.6	−35 51	11.7	SBab	2.8	50	58	1296
ESO 358-60	03 45.2	−35 34	15.6	Irr	1.7	30		710
NGC 1437B	03 45.9	−36 22	14.0	Sc	2.5	45	69	1415
	03 46.2	−36 42	13.5	SB0	1.7	30	63	1341
PGC 13809	03 46.3	−34 57	12.6	Sc	4.8	90		1838
	03 47.1	−33 42	12.6	(R')SA(s)bc	2.5	45	50	1057
ESO 302-09	03 47.6	−38 35	14.6	SBd	2.2	40		908
ESO 302-14	03 51.7	−38 27	15.5	Irr	1.5	30		798
ESO 359-03	03 52.0	−33 28	14.1	Sab	1.8	35		1495
	03 54.3	−36 58	13.9	Sb	2.5	45	48	952
	03 54.3	−35 58	12.5	E	1.9	35	65	1382
	04 11.2	−32 51	12.9	S0	1.3	15	57	1169
	04 12.1	−32 52	10.7	SBb	12.6	210	57

(*) - Membership is uncertain

See also

• List of galaxy groups and clusters
• Coma Cluster
• Eridanus Cluster
• Norma Cluster
• Virgo Cluster
• NGC 1365

Notes and References

1. Jordán . A. . Blakeslee . J. P. . Côté . P. . Ferrarese . L. . Infante . L. . Mei . S. . Merritt . D. . David Merritt . Peng . E. W. . Tonry . J. . West . Michael J. . June 2006 . The Astrophysical Journal Supplement Series . 452 . 1 . 141–153 . The ACS Fornax Cluster Survey. I. Introduction to the Survey and Data Reduction Procedures . 2007ApJS..169..213J . 10.1086/512778 . astro-ph/0702320 . 17845709 . 8 .
2. Drinkwater. Michael J.. Gregg. Michael D.. Colless. Matthew. 2001-02-01. Substructure and Dynamics of the Fornax Cluster. The Astrophysical Journal Letters. 548. 2 . L139–L142. 10.1086/319113. astro-ph/0012415 . 2001ApJ...548L.139D . 13456590 . 0004-637X.
3. Web site: Hubble Heritage Project. Dwarf Irregulars and Galaxy Clusters. 2006-12-07.
4. Web site: Chandra X-Ray Observatory. Fornax Cluster: Motions of Nearby Galaxy Cluster Reveal Presence of Hidden Superstructure. 2006-12-07.
5. Drinkwater. Michael J.. Gregg. Michael D.. Colless. Matthew. February 2001. The Astrophysical Journal Letters. 548. 2. L139. Substructure and Dynamics of the Fornax Cluster . 10.1086/319113. astro-ph/0012415. 2001ApJ...548L.139D . 13456590.
6. Web site: Fornax Cluster: Motions of Nearby Galaxy Cluster Reveal Presence of Hidden Superstructure . NASA . 30 April 2005 . 10 December 2012.
7. Neill. James D.. Shara. Michael M.. Oegerle. William R.. January 2005. The Astrophysical Journal. 618. 2. 692–704. Tramp Novae between Galaxies in the Fornax Cluster: Tracers of Intracluster Light. astro-ph/0409265 . 2005ApJ...618..692N . 10.1086/426049 . 5649912.