{{Short description|Cluster of galaxies in the constellation of Pisces}} {{Galaxy cluster | name = CL0024+17 | image = 300px |caption = The CL0024+17 cluster of galaxies<br>Credit: NASA/ESA/HST | epoch=J2000 | ra = {{RA|0|26|35}}<ref name="hubb">{{cite web | title=HubbleSite NewsCenter | work=Results for Cl 0024+17 | url=http://hubblesite.org/newscenter/archive/releases/2007/17/fastfacts/ | access-date=2007-05-16}}</ref> | dec = {{DEC|+17|9|43}}<ref name="hubb" /> | constellation = Pisces<ref name="hubb" /> | member_no = | brightest_member = | other_names = ZwCl 0024+1652<ref name="hubb" /> |redshift=0.39|mass=8.1x10^14}} [[Image:CL0024+17.jpg|thumb|right|300px|The gravity map is superimposed on a Hubble image of the cluster CL0024+17. Credit: NASA/ESA/HST]] '''CL0024+17''', or '''CL0024+1654''', is a cluster of galaxies located in the constellation Pisces, and about 4 billion light years distant. It appears as a concentration of yellow elliptical and spiral type galaxies.<ref>{{Cite web |last=information@eso.org |title=Ground-based image of the galaxy cluster CL0024+1654 |url=https://www.esahubble.org/images/heic0309c/ |access-date=2025-07-28 |website=www.esahubble.org |language=en}}</ref><ref>{{Cite web |last=information@eso.org |title=Galaxy Cluster 0024+1654 as a Gravitational Lens |url=https://www.esahubble.org/images/opo9610a/ |access-date=2025-07-28 |website=www.esahubble.org |language=en}}</ref> It has a radius of 0.54 mpc and a mass of 8.1x10^14 solar masses.<ref>{{Cite journal |last1=Dye |first1=S. |last2=Taylor |first2=A. N. |last3=Greve |first3=T. R. |last4=Rögnvaldsson |first4=Ö E. |last5=Kampen |first5=E. van |last6=Jakobsson |first6=P. |last7=Sigmundsson |first7=V. S. |last8=Gudmundsson |first8=E. H. |last9=Hjorth |first9=J. |date=2002-04-01 |title=Lens magnification by CL0024+1654 in the and band |url=https://www.aanda.org/articles/aa/abs/2002/16/aa1846/aa1846.html |journal=Astronomy & Astrophysics |language=en |volume=386 |issue=1 |pages=12–30 |doi=10.1051/0004-6361:20020226 |arxiv=astro-ph/0108399 |bibcode=2002A&A...386...12D |issn=0004-6361}}</ref> The cluster's large mass gravitationally lensed a background galaxy, creating eight well-resolved images of this galaxy.<ref name=":0">{{Citation |last1=Tyson |first1=J. Anthony |title=Detailed Mass Map of CL 0024+1654 from Strong Lensing |date=1998-05-02 |last2=Kochanski |first2=Greg P. |last3=Dell'Antonio |first3=Ian P. |journal=The Astrophysical Journal |volume=498 |issue=2 |pages=L107–L110 |doi=10.1086/311314 |arxiv=astro-ph/9801193 |bibcode=1998ApJ...498L.107T }}</ref>
Cl 0024+17 is allowing astronomers to probe the distribution of dark matter in space. The blue streaks near the center of the image are the smeared images of very distant galaxies that are not part of the cluster. The distant galaxies appear distorted because their light is being bent and magnified by the powerful gravity of Cl 0024+17, an effect called gravitational lensing.
Because dark matter does not shine or reflect light, it cannot be seen. Astronomers can only detect its influence by how its gravity affects light. By mapping the distorted light created by gravitational lensing, astronomers can trace how dark matter is distributed in the cluster. While mapping the dark matter, astronomers found a dark-matter ring near the cluster's center (although this is disputed by other independent studies<ref>{{Cite journal|title=Systematics in lensing reconstruction: dark matter rings in the sky?| journal = Astronomy and Astrophysics| volume = 535 | pages = 119–130| year = 2011| last1 = Ponente | first1 = P.P | last2 = Diego | first2 = J.M | doi = 10.1051/0004-6361/201117382| arxiv = 1110.3979| bibcode = 2011A&A...535A.119P| s2cid = 11608104}}</ref>). The ring's discovery is among the strongest evidence that dark matter exists.
Excluding mass concentrations centered on the visible galaxies, more than 98% of the remaining mass in the cluster is represented by dark matter. This dark matter is centered near the brightest galaxies of the cluster. The distribution of this dark matter far more smoother and symmetrical than predicted in CDM cosmologies such as Omega-1 and Omega-0.3.<ref name=":0" />
==References== {{reflist}}
==External links== * [http://hubblesite.org/newscenter/archive/releases/2007/17/full/ HubbleSite NewsCenter: Hubble pictures of CL0024+17 group] * [http://www.spacetelescope.org/news/html/heic0709.html Press release and more images and video presentations of CL0024+17 at Spacetelescope.org]
Category:Pisces (constellation) Category:Galaxy clusters