M60-UCD1
{{Short description|Galaxy in the constellation Virgo}}
{{Infobox galaxy
| name = M60-UCD1
| image = M60-UCD1 by HST.jpg
| image_size =
| upright = 1.2
| caption = A picture of M60-UCD1 taken by the Hubble Space Telescope
| credit = NASA, ESA, CXC, and J. Strader (Michigan State University)
| alt =
| epoch = J2000.0
| constellation name = Virgo
| ra = {{Deg2HMS|190.8999|sup=yes}}{{cite journal
| author=Strader, J.
| display-authors=etal
| date=2013
| title=The Densest Galaxy
| journal=The Astrophysical Journal
| volume=775
| issue=1
| pages=L6
| bibcode=2013ApJ...775L...6S
| arxiv=1307.7707
| doi=10.1088/2041-8205/775/1/L6}}
| dec = {{Deg2DMS|11.5347|sup=yes}}
| h_radial_v = {{val|1278|0|fmt=commas|ul=km/s}}
| gal_v = {{val|1229|2|fmt=commas|ul=km/s}}
| dist_ly = {{cvt|14.9|+/-|1.0|Mpc|Mly|sigfig=4|abbr=on|lk=on|order=flip}}{{hub|0.6774}}
{{small|(Comoving)}}{{cite web |url=https://ned.ipac.caltech.edu/cgi-bin/objsearch?objname=ESO+97-G13&extend=no&hconst=67.74&omegam=0.3089&omegav=0.6911&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 |title=Detailed Information for Object ESO 97-G13 |work=NASA/IPAC Extragalactic Database |access-date=September 16, 2023}}
| group_cluster = M60 Group
| type =
| mass = {{Val|2.0|0.3|e=8}} {{small|(dynamical mass)}}
| mass_light_ratio =
| size = {{cvt|48.4|+/-|1.0|pc|ly|sigfig=3|abbr=on|lk=on|disp=x|
(|)|order=flip}}
{{small|(Half-light diameter)}}
| stars =
| appmag_b =
| absmag_v =
| size_v =
| half_light_radius_pc = {{cvt|24.2|+/-|0.5|pc|ly|sigfig=3|abbr=on|lk=on|order=flip}}
| half_light_radius_arcminsec =
| h1_scale_length_pc =
| h1_scale_length_arcminsec =
| xray_radius_pc =
| xray_radius_arcminsec =
| notes =
| names = {{odlist | name=M60-UCD1 | SDSS=J124335.96+113204.6 }}
| references = {{cite simbad|title= NAME M60-UCD1 |accessdate=2021-02-19}}
}}
M60-UCD1 is an ultracompact dwarf galaxy. It is 49 million light years from Earth, close to Messier 60 (M60, NGC 4649) in the Virgo Cluster. Half of its stellar mass is in the central sphere 160 light years in diameter.{{cite web |title= Astronomers Discover Densest Galaxy Ever |url= https://www.sciencedaily.com/releases/2013/09/130924141701.htm |publisher= ScienceDaily |access-date= 26 September 2013 }}
Characteristics
File:Artist’s concept of supermassive black hole within M60-UCD1.tif
M60-UCD1's dynamical mass is {{val|200|30}} million solar masses ({{solar mass|link=y}}). Colours and lack of colour gradients indicate a uniform stellar population about {{val|14.5|0.5|u=billion years old}}
(indistinguishable from the age of the Universe).{{cite journal
| author=Seth, A.
| display-authors=etal
| date=2014
| title=A Supermassive Black Hole in an Ultracompact Dwarf Galaxy
| journal=Nature
| volume=513
| issue=7518
| pages=398–400
| bibcode=2014Natur.513..398S
| arxiv=1409.4769
| doi=10.1038/nature13762| pmid=25230660
}} Their metallicity is similar to that of the Sun. The orbital velocity dispersion of the innermost stars exceeds 100 km/s, due to the gravity of a dense mass concentration. The galactic nucleus contains a bright and variable X-ray source, presumably a supermassive black hole with a mass of {{solar mass|20 million}} (10% of the dynamical mass of the entire galaxy).{{cite web |url= http://www.nasa.gov/mission_pages/chandra/multimedia/m60-dense-galaxy.html |title= M60-UCD1: An Ultra-Compact Dwarf Galaxy |publisher= NASA |access-date= 25 September 2013 }} With this proportion of the mass of the black hole to that of the whole galaxy, it is one of the most black hole dominated galaxies known.
M60-UCD1 is believed to be the stripped core of a much more massive galaxy, whose mass was stripped in an encounter with M60 some 10 billion years ago. It may yet be absorbed completely by M60, its central black hole merging with M60's as well. The galaxy may have once had some 10 billion stars.{{cite news |publisher= ScienceNews |url= https://www.sciencedaily.com/releases/2014/09/140917131625.htm |title= Smallest known galaxy with a supermassive black hole |date= 17 September 2014 }}
As of 2013, it is possibly the densest known galaxy with over one hundred stars per cubic light-year.{{cite web |url= http://phys.org/news/2013-09-evidence-densest-galaxy-nearby-universe.html |title= Evidence for densest galaxy in nearby universe |publisher= Phys.org |date= 24 September 2013 |access-date= 25 September 2013 }} As of 2014, it is the smallest and least massive galaxy known to host a central black hole. It was previously known as the most massive ultracompact dwarf galaxy known.
See also
- M85-HCC1 – densest galaxy known, as of 2015.
References
{{reflist}}
Further reading
- Seth, Anil; van den Bosch, Remco; Mieske, Steffen; Baumgardt, Holger; den Brok, Mark; Strader, Jay; Neumayer, Nadine; Chilingarian, Igor; Hilker, Michael; McDermid, Richard; Brodie, Jean; Frank, Matthias; Walsh, Jonelle L.; "A Supermassive Black Hole in an Ultracompact Dwarf Galaxy", Nature, 513, pages 398–400, 18 September 2014; {{doi|10.1038/nature13762}}; {{arXiv|1409.4769}}; {{bibcode|2014arXiv1409.4769S}}
External links
- Chandra X-Ray Observatory, [http://chandra.harvard.edu/press/13_releases/press_092413.html "NASA's Hubble and Chandra Find Evidence for Densest Nearby Galaxy"], NASA, 24 September 2013
- ScienceDaily, [https://www.sciencedaily.com/releases/2013/09/130924141659.htm "Evidence for Densest Nearby Galaxy"], 24 September 2013
- ScienceDaily, [https://www.sciencedaily.com/releases/2013/09/130924141701.htm "Astronomers Discover Densest Galaxy Ever"], 24 September 2013
- {{APOD |date=October 4, 2013|title=The Densest Galaxy}}
{{galaxy}}
{{Virgo (constellation)}}
{{2013 in space}}
{{DEFAULTSORT:M60-UCD1}}