View source for NGC 4151

{{Short description|Galaxy in the constellation Canes Venatici}}
{{Infobox Galaxy
| name = [[New General Catalogue|NGC]] 4151
| image = NGC4151 Galaxy from the Mount Lemmon SkyCenter Schulman Telescope courtesy Adam Block.jpg
 |caption = Image of NGC 4151 from the 0.8m Schulman Telescope at the [[Mount Lemmon Observatory|Mount Lemmon SkyCenter]]
| epoch = [[J2000]]
| type = (R')[[Intermediate spiral galaxy|SAB]](rs)ab,<ref name="ned">{{cite web
  | publisher= NASA/IPAC Extragalactic Database
  | title= Results for NGC 4151
  | url= http://nedwww.ipac.caltech.edu/
  | access-date= 2007-03-27
  }}</ref> [[Seyfert galaxy|Sy1]]<ref name="simbad">{{cite simbad
  | title= NGC 4151
  | access-date= 2014-06-06
  }}</ref>
| ra = {{RA|12|10|32.6}}<ref name="ned" />
| dec = {{DEC|+39|24|21}}<ref name="ned" />
| dist_ly = {{convert|15.8|±|0.4|Mpc|e6ly|abbr=on|lk=off}}<ref>{{cite journal|doi=10.3847/1538-4357/abb377|title=The Cepheid Distance to the Seyfert 1 Galaxy NGC 4151|year=2020|last1=Yuan|first1=W.|last2=Fausnaugh|first2=M. M.|last3=Hoffmann|first3=S. L.|last4=Macri|first4=L. M.|last5=Peterson|first5=B. M.|last6=Riess|first6=A. G.|last7=Bentz|first7=M. C.|last8=Brown|first8=J. S.|last9=Bontà|first9=E. Dalla|last10=Davies|first10=R. I.|last11=Rosa|first11=G. De|last12=Ferrarese|first12=L.|last13=Grier|first13=C. J.|last14=Hicks|first14=E. K. S.|last15=Onken|first15=C. A.|last16=Pogge|first16=R. W.|last17=Storchi-Bergmann|first17=T.|last18=Vestergaard|first18=M.|journal=The Astrophysical Journal|volume=902|issue=1|page=26|arxiv=2007.07888|bibcode=2020ApJ...902...26Y|s2cid=220546047 |doi-access=free }}</ref>
| z = 0.003262<ref name="simbad"/><br/> 995 ± 3 km/[[second|s]]<ref name="ned" />
| appmag_v = 11.5<ref name="ned" />
| size_v =  6.4{{prime}} × 5.5{{prime}}<ref name="ned" />
| constellation name = [[Canes Venatici]]
| size               = ~{{convert|16.66|kpc|ly|abbr=on|lk=on|order=flip}} (estimated)<ref name="ned"/>
| notes =
| names = [[Uppsala General Catalogue|UGC]] 7166,<ref name="ned" /> [[Principal Galaxies Catalogue|PGC]] 38739<ref name="ned" />
}}

'''NGC 4151''' is an [[intermediate spiral galaxy|intermediate spiral]] [[Seyfert galaxy]] with weak inner ring structure located {{convert|15.8|Mpc|e6ly|abbr=off|lk=on}} from [[Earth]]<ref name="W. M. Keck Observatory-2014-11-26">{{cite web |title= 'Eye of Sauron' Provides New Way of Measuring Distances to Galaxies |url= http://www.keckobservatory.org/recent/entry/eye_of_sauron_provides_new_way_of_measuring_distances_to_galaxies |access-date= 2014-11-27 |date= 2014-11-26 |publisher= W. M. Keck Observatory |author= W. M. Keck Observatory |archive-url= https://web.archive.org/web/20141205035754/http://www.keckobservatory.org/recent/entry/eye_of_sauron_provides_new_way_of_measuring_distances_to_galaxies |archive-date= 2014-12-05 |url-status= dead }}</ref> in the constellation [[Canes Venatici]].  The galaxy was first mentioned by [[William Herschel]] on March 17, 1787; it was one of the six Seyfert galaxies described in the paper <ref name="seyfert1943">{{cite journal
  | author=C. K. Seyfert
  | title=Nuclear Emission in Spiral Nebulae
  | journal=Astrophysical Journal
  | date=1943
  | volume=97
  | pages=28–40
  | bibcode=1943ApJ....97...28S
  | doi=10.1086/144488
}}</ref> which defined the term. It is one of the nearest galaxies to Earth to contain an actively growing supermassive [[black hole]].<ref>{{cite web|title=NGC 4151: An active black hole in the "Eye of Sauron"|url=http://www.astronomy.com/News-Observing/News/2011/03/NGC%204151%20active%20black%20hole%20in%20the%20Eye%20of%20Sauron.aspx|publisher=Astronomy magazine|access-date=2011-03-14|date=2011-03-11|archive-date=2019-03-29|archive-url=https://web.archive.org/web/20190329112815/http://www.astronomy.com/News-Observing/News/2011/03/NGC|url-status=dead}}</ref> The black hole would have a mass on the order of 2.5 million to 30 million solar masses.<ref>{{cite journal|doi=10.3847/1538-4357/ac05b6|arxiv=2106.02758 |title=The Black Hole Mass of NGC 4151 from Stellar Dynamical Modeling |year=2021 |last1=Roberts |first1=Caroline A. |last2=Bentz |first2=Misty C. |last3=Vasiliev |first3=Eugene |last4=Valluri |first4=Monica |last5=Onken |first5=Christopher A. |journal=The Astrophysical Journal |volume=916 |issue=1 |page=25 |bibcode=2021ApJ...916...25R |s2cid=235358825 |doi-access=free }}</ref> It was speculated that the nucleus may host a binary black hole, with about 40 million and about 10 million solar masses respectively, orbiting with a 15.8-year period.<ref>{{Cite journal| arxiv=1209.4524 | display-authors=4 | author1=Bon | author2=Jovanović | author3=Marziani | author4=Shapovalova | author5=Bon | author6=Borka Jovanović | author7=Borka | author8=Sulentic | author9=Popović | title=The First Spectroscopically Resolved Sub-parsec Orbit of a Supermassive Binary Black Hole | journal=The Astrophysical Journal | volume=759 | issue=2 | pages=118–125 | date=2012| doi=10.1088/0004-637X/759/2/118 |bibcode = 2012ApJ...759..118B | s2cid=119257514 }}</ref> This is, however, still a matter of active debate.

Some astronomers nickname it the "[[Eye of Sauron]]" from its appearance.<ref>{{cite web |url= http://chandra.harvard.edu/photo/2011/n4151/ |title= NGC 4151: An Active Black Hole in the "Eye of Sauron" |publisher= Chandra X-ray Center |author= Chandra X-ray Observatory |date= 10 March 2011 }}</ref>

One [[supernova]] has been observed in NGC 4151:  SN 2018aoq ([[Type_II_supernova|Type II-P]], mag 15.3).<ref>[https://www.wis-tns.org/object/2018aoq Transient Name Server entry for SN 2018aoq.] Retrieved 5 January 2023.</ref><ref>{{Cite journal |last1=Tsvetkov |first1=D. Yu. |last2=Pavlyuk |first2=N. N. |last3=Vozyakova |first3=O. V. |last4=Shatsky |first4=N. I. |last5=Tatarnikov |first5=A. M. |last6=Nikiforova |first6=A. A. |last7=Baklanov |first7=P. V. |last8=Blinnikov |first8=S. I. |last9=Ushakova |first9=M. G. |last10=Larionova |first10=E. G. |last11=Borman |first11=G. A. |date=2021 |title=Type II-P Supernova SN 2018aoq in NGC 4151: Light Curves, Models, and Distance |url=https://doi.org/10.1134/S1063773721050078 |journal=Astronomy Letters |language=en |volume=47 |issue=5 |pages=291–306 |doi=10.1134/S1063773721050078|bibcode=2021AstL...47..291T |url-access=subscription }}</ref>

NGC 4151 is a member of a group of 9 galaxies<ref name=":0">{{Cite book |last=Tully |first=R. Brent |title=Nearby galaxies catalog |date=1988 |publisher=Cambridge University Press |isbn=978-0-521-35299-4 |edition=1. publ |location=Cambridge}}</ref><ref>{{Cite journal |last1=Kourkchi |first1=Ehsan |last2=Tully |first2=R. Brent |date=July 2017 |title=Galaxy Groups Within 3500 km s-1 |journal=The Astrophysical Journal |language=en |volume=843 |issue=1 |pages=16 |doi=10.3847/1538-4357/aa76db |doi-access=free |arxiv=1705.08068 |bibcode=2017ApJ...843...16K |issn=0004-637X}}</ref> known as the [[NGC 4151 Group]].<ref name=":1">{{Cite journal |last1=Fouque |first1=P. |last2=Gourgoulhon |first2=E. |last3=Chamaraux |first3=P. |last4=Paturel |first4=G. |date=May 1992 |title=Groups of galaxies within 80 Mpc. II. The catalogue of groups and group members. |url=https://ui.adsabs.harvard.edu/abs/1992A&AS...93..211F/abstract |journal=Astronomy and Astrophysics Supplement Series |language=en |volume=93 |pages=211–233 |bibcode=1992A&AS...93..211F |issn=0365-0138}}</ref><ref>{{Cite journal |last1=Giuricin |first1=Giuliano |last2=Marinoni |first2=Christian |last3=Ceriani |first3=Lorenzo |last4=Pisani |first4=Armando |date=November 2000 |title=Nearby Optical Galaxies: Selection of the Sample and Identification of Groups |url=https://iopscience.iop.org/article/10.1086/317070 |journal=The Astrophysical Journal |language=en |volume=543 |issue=1 |pages=178–194 |doi=10.1086/317070 |arxiv=astro-ph/0001140 |bibcode=2000ApJ...543..178G |issn=0004-637X}}</ref> The NGC 4151 Group is part of the [[Ursa Major Cloud]],<ref name=":0" /><ref>{{Cite journal |last1=Karachentsev |first1=I. D. |last2=Nasonova |first2=O. G. |last3=Courtois |first3=H. M. |date=March 2013 |title=Anatomy of Ursa Majoris |journal=Monthly Notices of the Royal Astronomical Society |language=en |volume=429 |issue=3 |pages=2264–2273 |doi=10.1093/mnras/sts494 |doi-access=free |arxiv=1211.5975 |bibcode=2013MNRAS.429.2264K |issn=0035-8711}}</ref> which is part of the [[Virgo Supercluster]].<ref name=":1" /> 

==X-ray source==
[[File:NGC 4151.jpg|thumb|upright=1.0|left|NGC 4151. X-rays (blue), optical data (yellow), radio observation (red)]]
[[File:NGC 4151 - HST.png|thumb|left|NGC 4151, by [[Hubble Space Telescope|HST]] (WFC3).]]
[[File:Seyfert galaxy NGC4151 (GL-2002-001035).jpg|thumb|left|Optical and ultraviolet images of the black hole in the center of NGC 4151]]
[[File:X-ray 'Echoes' Probe Habitat of Monster Black Hole.ogv|thumb|upright=1.2|right|Astronomers using data from the European Space Agency's [[XMM-Newton]] satellite have found a long-sought X-ray signal from NGC 4151. When the black hole's X-ray source flares, its accretion disk reflects the emission about half an hour later.]]

X-ray emission from NGC 4151 was apparently first detected on December 24, 1970, with the X-ray observatory satellite [[Uhuru (satellite)|Uhuru]],<ref name=Gursky71>{{cite journal |author=Gursky H |display-authors=4 |author2=Kellogg EM |author3= Leong C |author4=Tananbaum H |author5=Giacconi R |title=Detection of X-Rays from the Seyfert Galaxies NGC 1275 and NGC 4151 by the UHURU Satellite |journal=Astrophys J |date=Apr 1971 |volume=165 |issue=4 |pages=L43–8 |bibcode=1971ApJ...165L..43G |doi=10.1086/180713 |doi-access=free }}</ref> although the observation  spanned an error-box of 0.56 square degrees and there is some controversy as to whether UHURU might not have detected the [[BL Lac object]] 1E 1207.9 +3945, which is inside their error box – the later [[HEAO 1]] detected an X-ray source of NGC 4151 at 1H 1210+393,<ref name=Wood>{{cite journal |doi=10.1086/190992 |author=Wood KS |display-authors=4 |author2=Meekins JF |author3=Yentis DJ |author4=Smathers HW |author5=McNutt DP |author6=Bleach RD |title=The HEAO A-1 X-ray source catalog |journal=Astrophys. J. Suppl. Ser. |date=December 1984 |volume=56 |issue=12 |pages=507–649 |bibcode=1984ApJS...56..507W |doi-access=free }}</ref> coincident with the optical position of the nucleus and outside the error box of Uhuru.<ref name="Gursky71"/>

To explain the X-ray emission two different possibilities have been proposed:<ref name="NASA-2011-03-10">{{cite web |title= The 'Eye of Sauron' |url= http://www.nasa.gov/mission_pages/chandra/multimedia/11-029.html |access-date= 2011-03-14 |date= 2011-03-10 |publisher= NASA |author= Chandra X-Ray Observatory |archive-date= 2011-04-23 |archive-url= https://web.archive.org/web/20110423180644/http://www.nasa.gov/mission_pages/chandra/multimedia/11-029.html |url-status= dead }}</ref>

* radiation of material falling onto the central black hole (which was growing much more quickly about 25,000 years ago) was so bright that it stripped [[electron]]s away from the [[atom]]s in the gas in its path, and then electrons recombined with these ionized atoms
* the energy released by material flowing into the black hole in an [[accretion disk]] created a vigorous outflow of gas from the surface of the disk, which directly heated gas in its path to X-ray emitting temperatures

{{clear-left}}

==See also==
* [[X-ray astronomy]]

==References==
{{Reflist|30em}}

==External links==
{{Commons category}}
* [http://hubblesite.org/newscenter/archive/releases/1997/18/image/a/ Hubble site news center: Fireworks Near a Black Hole in the Core of Seyfert Galaxy NGC 4151]

{{Catalogs|NGC=4151|UGC=7166|PGC=38739}}
{{Ngc45}}
{{Canes Venatici}}
{{Authority control}}

{{DEFAULTSORT:NGC 4151}}
[[Category:Galaxies discovered in 1787]]
[[Category:Intermediate spiral galaxies]]
[[Category:Seyfert galaxies]]
[[Category:Canes Venatici]]
[[Category:NGC objects|4151]]
[[Category:UGC objects|07166]]
[[Category:Principal Galaxies Catalogue objects|38739]]
[[Category:X-ray astronomy]]
[[Category:Astronomical X-ray sources]]
[[Category:Articles containing video clips]]
[[Category:Astronomical objects discovered in 1787|17870317]]
[[Category:NGC 4151 Group]]