{{Short description|Galaxy in the constellation Boötes}} {{Sky|14|18|25.708|+|36|29|37.28}} {{Infobox galaxy | image = [[File:NGC5557 - SDSS DR14.jpg|250px]] | alt = NGC 5557 | caption = [[Sloan Digital Sky Survey|SDSS]] image of NGC 5557 | epoch = [[J2000]] | constellation name = [[Boötes]] | ra = {{RA|14|18|25.708}}<ref name=2MASS>{{cite journal |doi=10.1086/498708 |last1=Skrutskie |first1=Michael F. |last2=Cutri |first2=Roc M. |last3=Stiening |first3=Rae |last4=Weinberg |first4=Martin D. |last5=Schneider |first5=Stephen E. |last6=Carpenter |first6=John M. |last7=Beichman |first7=Charles A. |last8=Capps |first8=Richard W. |last9=Chester |first9=Thomas |last10=Elias |first10=Jonathan H. |last11=Huchra |first11=John P. |last12=Liebert |first12=James W. |last13=Lonsdale |first13=Carol J. |last14=Monet |first14=David G. |last15=Price |first15=Stephan |last16=Seitzer |first16=Patrick |last17=Jarrett |first17=Thomas H. |last18=Kirkpatrick |first18=J. Davy |last19=Gizis |first19=John E. |last20=Howard |first20=Elizabeth V. |last21=Evans |first21=Tracey E. |last22=Fowler |first22=John W. |last23=Fullmer |first23=Linda |last24=Hurt |first24=Robert L. |last25=Light |first25=Robert M. |last26=Kopan |first26=Eugene L. |last27=Marsh |first27=Kenneth A. |last28=McCallon |first28=Howard L. |last29=Tam |first29=Robert |last30=Van Dyk |first30=Schuyler D. |last31=Wheelock |first31=Sherry L. |title=The Two Micron All Sky Survey (2MASS) |journal=The Astronomical Journal |date=1 February 2006 |volume=131 |issue=2 |pages=1163–1183 |bibcode=2006AJ....131.1163S |s2cid=18913331 |issn=0004-6256 |doi-access=free }}</ref> | dec = {{DEC|+36|29|37.28}}<ref name=2MASS/> | h_radial_v = 3210 ± 28 km/s<ref name=SIMBAD/> | z = 0.010764<ref name=SIMBAD/> | dist_ly = {{cvt|38.8|Mpc|Mly|lk=on|order=flip}}<ref name=Duc>{{cite journal|doi=10.1111/j.1365-2966.2011.19137.x|title=The ATLAS<sup>3D</sup> project - IX. The merger origin of a fast- and a slow-rotating early-type galaxy revealed with deep optical imaging: First results|year=2011|last1=Duc|first1=Pierre-Alain|last2=Cuillandre|first2=Jean-Charles|last3=Serra|first3=Paolo|last4=Michel-Dansac|first4=Leo|last5=Ferriere|first5=Etienne|last6=Alatalo|first6=Katherine|last7=Blitz|first7=Leo|last8=Bois|first8=Maxime|last9=Bournaud|first9=Frédéric|last10=((Bureau))|first10=Martin|last11=Cappellari|first11=Michele|last12=Davies|first12=Roger L.|last13=Davis|first13=Timothy A.|last14=De Zeeuw|first14=P. T.|last15=Emsellem|first15=Eric|last16=Khochfar|first16=Sadegh|last17=Krajnović|first17=Davor|last18=Kuntschner|first18=Harald|last19=Lablanche|first19=Pierre-Yves|last20=McDermid|first20=Richard M.|last21=Morganti|first21=Raffaella|author21-link=Raffaella Morganti|last22=Naab|first22=Thorsten|last23=Oosterloo|first23=Tom|last24=Sarzi|first24=Marc|last25=Scott|first25=Nicholas|last26=Weijmans|first26=Anne-Marie|last27=Young|first27=Lisa M.|journal=Monthly Notices of the Royal Astronomical Society|volume=417|issue=2|pages=863–881|doi-access=free |arxiv=1105.5654|bibcode=2011MNRAS.417..863D|s2cid=6762647}}</ref> | group_cluster = | type = E1<ref name=Duc/> | size = | appmag_v = 12.2<ref name=cseligman>{{cite web|url=http://cseligman.com/text/atlas/ngc55a.htm#5557|title=New General Catalogue objects: NGC 5550 - 5599|author=Seligman, Courtney|website=cseligman.com|access-date=2021-04-17}}</ref> | appmag_b = | absmag_v = −22.39<ref name=Bonfini>{{cite journal|doi=10.1086/678566|title=GALFIT-CORSAIR: Implementing the Core-Sérsic Model into GALFIT|year=2014|last1=Bonfini|first1=Paolo|journal=Publications of the Astronomical Society of the Pacific|volume=126|issue=944|pages=935–947|arxiv=1408.6846|bibcode=2014PASP..126..935B|s2cid=119256809}}</ref> | size_v = | names = {{odlist|UGC=9161|MCG=+06-31-093|PGC=51104}}<ref name=SIMBAD>{{cite simbad|title=NGC 5557|accessdate=2021-04-17}}</ref> }}
'''NGC 5557''' is an [[elliptical galaxy]] in the [[constellation]] [[Boötes (constellation)|Boötes]]. It was discovered by [[William Herschel]] on May 1, 1785.<ref name=cseligman/> The distance to NGC 5557 is not well known, but it is estimated to be about 127 million light-years (38.8 megaparsecs) away.<ref name=Duc/>
NGC 5557 is quite massive, with a K-band [[absolute magnitude]] of −24.8, and is a slow rotator,<ref name=Duc/> which suggests it gained mass through dry mergers (galaxy mergers involving galaxies significant amounts of gas).<ref name=Bonfini/> However, it has a faint [[tidal tail]] to its east, as well as a more complex structure to the west. This structure, if found to be connected to NGC 5557, would one of the largest around a galaxy, spanning about 1.1 million light-years (350,000 parsecs).<ref name=Duc/> This filamentary structure suggests that NGC 5557 may have formed from a more gas-rich [[galaxy merger]] a couple billion years ago.<ref name=Duc/> This implies that the galaxy merger would need to have a low [[impact parameter]].<ref name=Bonfini/>
NGC 5557 is part of a [[galaxy group]],<ref name=Duc/><ref name=cseligman/> and is the largest such galaxy in the group by far.<ref name=Duc/> Surrounding the galaxy near the eastern filament are several small bluish objects, which are possibly tidal [[dwarf galaxies]].<ref name=Duc/>
==Supernovae== Two [[supernova]]e have been observed in NGC 5557: * '''SN 1996aa''' ([[type Ia supernova|Type Ia]], mag. 17) was discovered by Wayne Johnson on 16 May 1996.<ref>{{cite journal | bibcode=1996IAUC.6403....1J| title=Supernova 1996aa in NGC 5557| last1=Johnson| first1=W.| last2=Garnavich| first2=P.| last3=Riess| first3=A.| last4=Kirshner| first4=R.| last5=Barton| first5=E.| journal=International Astronomical Union Circular| date=1996| issue=6403| page=1 | url=http://www.cbat.eps.harvard.edu/iauc/06400/06403.html#Item1}}</ref><ref>{{cite web | website=Transient Name Server | title=SN 1996aa | url=https://www.wis-tns.org/object/1996aa | publisher = [[International Astronomical Union|IAU]] | access-date=9 December 2024}}</ref> * '''SN 2013gn''' (Type Ia, mag. 15.3) was discovered by [[Kōichi Itagaki]] on 16 November 2013.<ref>{{cite journal | bibcode=2013CBET.3727....1N| title=Supernova 2013gn in NGC 5557 = PSN J14182850+3630244| last1=Nakano| first1=S.| last2=Yusa| first2=T.| last3=Ueno| first3=I.| last4=Itoh| first4=R.| last5=Kawabata| first5=K. S.| last6=Yamanaka| first6=M.| last7=Ayani| first7=K.| last8=Yamaoka| first8=H.| journal=Central Bureau Electronic Telegrams| date=2013| issue=3727| page=1}}</ref><ref>{{cite web | website=Transient Name Server | title=SN 2013gn | url=https://www.wis-tns.org/object/2013gn | publisher = [[International Astronomical Union|IAU]] | access-date=9 December 2024}}</ref>
== References == {{Reflist}}
== External links == * {{commons category-inline}}
{{Catalogs|NGC=5557}} {{Ngc60}} {{Boötes}}
[[Category:Boötes]] [[Category:NGC objects|5557]] [[Category:Elliptical galaxies]]