Eridanus Cluster

{{short description|Galaxy cluster in the constellation Eridanus}}

{{distinguish|Eridanus Group}}

{{Infobox galaxy cluster

| name = Eridanus Cluster

| image =

| caption =

| credit =

| epoch = J2000

| ra = {{RA|03|28|13.8}}{{cite web

| title = Eridanus Cluster

| work = NASA/IPAC Extragalactic Database (NED)

| url = http://ned.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=ERIDANUS&extend=no

| access-date = 2012-02-25}}

| dec = {{DEC|-20|44|40}}

| constellation = Eridanus

| member_no = ~200

| brightest_member = NGC 1232 (B)

| richness =

| redshift = 0.005570

| distance = {{convert|23|Mpc|Mly|0|abbr=on|lk=on}}

| temperature = ~10⁷ K (~1 keV)

| mass = ~10¹⁴{{cite journal

| last1 = Willmer

| first1 = C. N. A.

| last2 = Rocardi

| first2 = P.

| last3 = da Costa

| first3 = L. Nicolaci

| last4 = Pellegrini

| first4 = P. S.

|date=November 1989

| title = Studies of nearby poor clusters – The Eridanus group

| journal = Astronomical Journal

| issn = 0004-6256

| volume = 98

| issue = Nov. 1989

| pages = 1531–1541

| bibcode = 1989AJ.....98.1531W

| doi = 10.1086/115236

| access-date = 2012-02-25

| url = http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1989AJ.....98.1531W&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf

}}

| velocity_dispersion = 261 km/s

| flux = 0.105 mCrab

| other_names = Fornax II Cluster,[http://www.atlasoftheuniverse.com/galgrps/for.html atlasoftheuniverse.com] de Vaucouleurs Group 31{{cite journal

| last1 = Chincarini

| first1 = G.

| last2 = Rood

| first2 = H. J.

| last3 = Welch

| first3 = G. A.

|date=March 1975

| title = A re-analysis of the dynamics of the nearby groups of galaxies

| journal = Monthly Notices of the Royal Astronomical Society

| volume = 170

| issue = Mar. 1975

| pages = 441–445

| id = A&AA ID. AAA013.160.006

| bibcode = 1975MNRAS.170..441C

| doi=10.1093/mnras/170.3.441

| doi-access = free

}}

}}

Image:NGC 1232.jpg is one of the brightest in the Eridanus Cluster.]]

File:Hubble2005-01-barred-spiral-galaxy-NGC1300.jpg is a well-known member of the Eridanus Cluster.]]

The Eridanus Cluster is a galaxy cluster roughly {{convert|23|Mpc|Mly|0|abbr=on|lk=on}} from Earth, containing about 73 main galaxies and about 200 total galaxies. About 30% have Hubble classifications of elliptical or S0 and the remaining 70% are spiral or irregular.{{cite journal

| last1 = Omar

| first1 = A.

| last2 = Dwarakanath

| first2 = K. S.

|date=March 2005

| title = GMRT HI Observations of the Eridanus Group of Galaxies I

| journal = Journal of Astrophysics and Astronomy

| volume = 26

| issue = 1

| pages = 1–33

| bibcode = 2005JApA...26....1O

| doi = 10.1007/BF02702451

| access-date = 2012-02-25

| url = http://www.ias.ac.in/jaa/mar2005/JAA416A.pdf

| arxiv = astro-ph/0503536 | s2cid = 7451092

}} These galaxies reside in smaller groups which are all loosely gravitationally bound to each other, suggesting that the system is still condensing from the Hubble flow and may eventually form a cluster of about 10¹⁴ {{Solar mass|link=y}}. A low velocity dispersion compared to that of, for example, the Coma cluster, supports this hypothesis. The Eridanus Cluster is located in the constellation Eridanus near the Fornax Cluster, and is sometimes called the "Fornax II Cluster".