NGC 5084

{{Infobox galaxy

| name = NGC 5084

| image = N5084s.jpg

| caption = NGC 5084 by 32 in Schulman Telescope

| epoch = J2000

| type = S0 {{cite web

| title=NASA/IPAC Extragalactic Database

| work=Results for NGC 5084

| url=http://ned.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=NGC+5084

| access-date=2016-01-18 }}

| ra = {{RA|13|20|16.9}}

| dec = {{DEC|-21|49|39}}

| dist_ly = 80.5 Mly (24.7 Mpc){{cite journal|last1=Theureau|first1=G.|last2=Hanski|first2=M. O.|last3=Coudreau|first3=N.|last4=Hallet|first4=N.|last5=Martin|first5=J.-M.|title=Kinematics of the Local Universe|journal=Astronomy & Astrophysics|date=19 December 2006|volume=465|issue=1|pages=71–85|doi=10.1051/0004-6361:20066187|arxiv=astro-ph/0611626|bibcode=2007A&A...465...71T|s2cid=14251529}}

| z = 0.005741 ± 0.000010

| h_radial_v = 1,721 ± 3 km/s

| appmag_v = 10.5{{cite web|title=NGC5084| work = HyperLeda |url=http://leda.univ-lyon1.fr/ledacat.cgi?o=NGC5084|publisher=University of Lyon}}

| size_v = 9.3{{prime}} × 1.7{{prime}}

| constellation name = Virgo

| notes = Supermassive disk galaxy

| names = ESO 576- G 033, MCG -04-32-004, PGC 46525

}}

NGC 5084 is a lenticular galaxy in the constellation of Virgo. It is located at a distance of about 80 million light years from Earth, which, given its apparent dimensions, means that NGC 5084 is at least 200,000 light years across. It is one of the largest and most massive galaxies in the Virgo Supercluster. William Herschel discovered it on March 10, 1785. It is a member of the NGC 5084 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.{{cite web | title=The Virgo III Groups |work=Atlas of the Universe |url=http://www.atlasoftheuniverse.com/galgrps/viriii.html |access-date=2010-11-27 }} The galaxy is seen nearly edge-on, with inclination 86°, and features a warped disk and large quantities of HI gas extending along the disk, probably accumulated after multiple accretions of smaller galaxies.

Mass and size estimates

NGC 5084 is a very massive system, with a high rotational speed of about 328 km/s.{{cite journal|last1=Gottesman|first1=S. T.|last2=Hawarden|first2=T. G.|title=Optical and high-resolution H I observations of the massive and unusual lenticular galaxy NGC 5084|journal=Monthly Notices of the Royal Astronomical Society|date=1 April 1986|volume=219|issue=4|pages=759–775|doi=10.1093/mnras/219.4.759|bibcode=1986MNRAS.219..759G|doi-access=free}} It is categorised as a supermassive disk galaxy.{{cite journal|author1=Buson, L. M. |author2=Galletta, G. |author3=Saglia, R. P. |author4=Zeilinger, W. W.|title=Supermassive disk galaxies|journal=ESO Messenger|volume=63 |date=March 1991|issue=63|pages=50–52|issn=0722-6691|bibcode=1991Msngr..63...50B}} Gottesen (1986) estimated based on the rotational speed that the mass of NGC 5084 is 8.5 x10¹¹ {{solar mass|link=yes}} and its radius to be 34 kpc (110 kly) for an estimated distance of 15.5 Mpc (50 Mly). Gottesman et al. (2002) using the same method adopted as distance the 30 Mpc and calculated the mass of NGC 5084 to be 1.7 x 10¹² {{solar mass}}.{{cite journal|last1=Gottesman|first1=S. T.|last2=Hunter|first2=J. H.|last3=Boonyasait|first3=V.|title=On the mass of M31|journal=Monthly Notices of the Royal Astronomical Society|date=November 2002|volume=337|issue=1|pages=34–40|doi=10.1046/j.1365-8711.2002.05793.x|doi-access=free |arxiv=astro-ph/0207450|bibcode=2002MNRAS.337...34G|s2cid=119429719}} Koribalski et al. (2004) measured the rotational speed of NGC 5084 to be 334 km/s and calculated its mass to be 1.3 × 10¹² and its radius was estimated at 50 kpc (163 Kly).{{cite journal|last1=Koribalski|first1=B. S.|last2=Staveley-Smith|first2=L.|last3=Kilborn|first3=V. A.|last4=Ryder|first4=S. D.|last5=Kraan-Korteweg|first5=R. C.|last6=Ryan-Weber|first6=E. V.|author6-link=Emma Ryan-Weber|last7=Ekers|first7=R. D.|last8=Jerjen|first8=H.|last9=Henning|first9=P. A.|last10=Putman|first10=M. E.|last11=Zwaan|first11=M. A.|last12=de Blok|first12=W. J. G.|last13=Calabretta|first13=M. R.|last14=Disney|first14=M. J.|last15=Minchin|first15=R. F.|last16=Bhathal|first16=R.|last17=Boyce|first17=P. J.|last18=Drinkwater|first18=M. J.|last19=Freeman|first19=K. C.|last20=Gibson|first20=B. K.|last21=Green|first21=A. J.|last22=Haynes|first22=R. F.|last23=Juraszek|first23=S.|last24=Kesteven|first24=M. J.|last25=Knezek|first25=P. M.|last26=Mader|first26=S.|last27=Marquarding|first27=M.|last28=Meyer|first28=M.|last29=Mould|first29=J. R.|last30=Oosterloo|first30=T.|last31=O'Brien|first31=J.|last32=Price|first32=R. M.|last33=Sadler|first33=E. M.|last34=Schröder|first34=A.|last35=Stewart|first35=I. M.|last36=Stootman|first36=F.|last37=Waugh|first37=M.|last38=Warren|first38=B. E.|last39=Webster|first39=R. L.|last40=Wright|first40=A. E.|title=The 1000 Brightest HIPASS Galaxies: H Properties|journal=The Astronomical Journal|date=July 2004|volume=128|issue=1|pages=16–46|doi=10.1086/421744|arxiv=astro-ph/0404436|bibcode=2004AJ....128...16K|s2cid=16229767}} Carrignan et al. (1997) measured the velocity differences and projected separations of nine galaxies they identified as satellites of NGC 5084 and using different equations they estimated the mass of NGC 5084 to be between 6 x 10¹² {{solar mass}} and 1 x 10¹³ {{solar mass}}, which was at that time the highest mass ever derived for a disk galaxy. They estimated the optical diameter of NGC 5084 to be 74 kpc (241 Kly).{{cite journal|last1=Carignan|first1=Claude|last2=Cote|first2=Stephanie|last3=Freeman|first3=Kenneth C.|last4=Quinn|first4=Peter J.|title=NGC 5084: A Massive Disk Galaxy Accreting its Satellites?|journal=The Astronomical Journal|date=May 1997|volume=113|pages=1585|doi=10.1086/118376|arxiv=astro-ph/9704032|bibcode=1997AJ....113.1585C|s2cid=9753595 }}

Nearby galaxies

NGC 5084 is the largest galaxy in the NGC 5084 group, which also includes NGC 5087 and NGC 5134 and some smaller galaxies. The galaxy group is compact, showing little redshift dispersion. NGC 5068 is a foreground galaxy.{{cite journal|last1=Firth|first1=P.|last2=Evstigneeva|first2=E. A.|last3=Jones|first3=J. B.|last4=Drinkwater|first4=M. J.|last5=Phillipps|first5=S.|last6=Gregg|first6=M. D.|title=Kinematics, substructure and luminosity-weighted dynamics of six nearby galaxy groups|journal=Monthly Notices of the Royal Astronomical Society|date=11 November 2006|volume=372|issue=4|pages=1856–1868|doi=10.1111/j.1365-2966.2006.10993.x|doi-access=free |arxiv=astro-ph/0608584|bibcode=2006MNRAS.372.1856F|s2cid=18646500}} Other nearby galaxy groups include the NGC 5078 group, which includes NGC 5078, NGC 5061, and NGC 5101, and NGC 4965 group.{{cite journal|last1=Makarov|first1=Dmitry|last2=Karachentsev|first2=Igor|title=Galaxy groups and clouds in the local (z~ 0.01) Universe|journal=Monthly Notices of the Royal Astronomical Society|date=21 April 2011|volume=412|issue=4|pages=2498–2520|doi=10.1111/j.1365-2966.2010.18071.x|doi-access=free |bibcode=2011MNRAS.412.2498M|arxiv=1011.6277|s2cid=119194025}} NGC 5084 is located at end of Virgo II groups, a filament of galaxy groups that extents southwards from the Virgo cluster.{{cite web|title=The Virgo II Groups|url=http://www.atlasoftheuniverse.com/galgrps/virii.html|website=www.atlasoftheuniverse.com}}