{{Short description|Radio galaxy located in the constellation Boötes}} {{Infobox galaxy|name=[[Uppsala General Catalogue|UGC]] 8669|constellation name=[[Boötes]]|epoch=[[J2000.0]]|ra={{RA|13|41|49.10}}<ref name="ned" />|dec={{DEC|+26|22|21.01}}<ref name="ned" />|z=0.075732<ref name="ned" />|h_radial_v=22,704 [[kilometer per second|km/s]]<ref name="ned" />|dist_ly=1.045 [[light years|Gly]]|type=Elliptical;BrCLG<ref name="ned" />|appmag_v=15.3|size=~{{convert|100|kpc|ly|abbr=on|lk=on|order=flip}} (estimated){{r|ned}}|notes=[[Radio galaxy]]|names=VV 195b, [[Morphological Catalogue of Galaxies|MCG]] +05-32-063, [[Catalogue of Galaxies and of Clusters of Galaxies|CGCG]] 161-121 NED01, [[2MASX]] J13414914+2622248, OGC 0935, KOS NP5 007, [[Principal Galaxies Catalogue|PGC]] 48495, [[Fourth Cambridge Survey|4C]] 26.41, B2 1339+26B|image=File:Image of UGC 8669.png|caption=[[Sloan Digital Sky Survey|SDSS]] image of UGC 8669.|group_cluster=Abell 1775}}
'''UGC 8669''' known as '''UGC 8669 NED01''' and '''B2 1339+26B''', is a [[radio galaxy]] located in the constellation of [[Boötes]]. The [[redshift]] of the galaxy is estimated to be (z) 0.075<ref name="ned">{{Cite web |title=NED Search results for UGC 8869 NED01 |url=https://ned.ipac.caltech.edu/byname?objname=LEDA+48495&hconst=67.8&omegam=0.308&omegav=0.692&wmap=4&corr_z=1 |access-date=2025-09-01 |website=NASA/IPAC Extragalactic Database}}</ref> and it was first discovered by astronomers in 1971,<ref name=":1" /> later designated as '''4C 26.41''' in 1977.<ref>{{Cite journal |last1=Miley |first1=G. K. |last2=Harris |first2=D. E. |date=November 1977 |title=Westerbork observations of three cluster radio galaxies. |url=https://ui.adsabs.harvard.edu/abs/1977A&A....61L..23M/abstract |journal=Astronomy and Astrophysics |language=en |volume=61 |pages=L23–L26 |bibcode=1977A&A....61L..23M |issn=0004-6361}}</ref> It is the [[brightest cluster galaxy]] (BCG), dominating the center of Abell 1775, an [[X-ray]] luminous and rich [[galaxy cluster]].<ref>{{Citation |last1=Liuzzo |first1=E. |title=The Bologna complete sample of nearby radio sources |date=2009-08-31 |last2=Giovannini |first2=G. |last3=Giroletti |first3=M. |last4=Taylor |first4=G. B. |journal=Astronomy & Astrophysics |volume=505 |issue=2 |pages=509–520 |doi=10.1051/0004-6361/200912586 |arxiv=0908.4391 |bibcode=2009A&A...505..509L }}</ref><ref>{{Cite journal |last1=Hu |first1=Dan |last2=Xu |first2=Haiguang |last3=Zhu |first3=Zhenghao |last4=Shan |first4=Chenxi |last5=Zhu |first5=Yongkai |last6=Fan |first6=Shida |last7=Zhao |first7=Yuanyuan |last8=Liu |first8=Chengze |last9=Siew |first9=Hoongwah |last10=Zhang |first10=Zhongli |last11=Gu |first11=Liyi |last12=Johnston-Hollitt |first12=Melanie |last13=Kang |first13=Xi |last14=Tan |first14=Qinghua |last15=Chang |first15=Jiang |date=2021-05-01 |title=The Merger Dynamics of the Galaxy Cluster A1775: New Insights from Chandra and XMM-Newton for a Cluster Simultaneously Hosting a Wide-angle Tail and a Narrow-angle Tail Radio Source |journal=The Astrophysical Journal |volume=913 |issue=1 |pages=8 |doi=10.3847/1538-4357/abf09e |arxiv=2103.03382 |bibcode=2021ApJ...913....8H |doi-access=free |issn=0004-637X}}</ref>
== Description == UGC 8669 is classified as a [[Fanaroff–Riley classification|Fanaroff-Riley class]] Type I radio galaxy. Its host is an [[elliptical galaxy]] with a small dark nuclear band.<ref>{{Cite journal |last1=Capetti |first1=A. |last2=de Ruiter |first2=H. R. |last3=Fanti |first3=R. |last4=Morganti |first4=R. |last5=Parma |first5=P. |last6=Ulrich |first6=M.-H. |date=October 2000 |title=The HST snapshot survey of the B2 sample of low luminosity radio-galaxies: a picture gallery |journal=Astronomy and Astrophysics |language=en |volume=362 |pages=871–885 |arxiv=astro-ph/0009056 |bibcode=2000A&A...362..871C |issn=0004-6361}}</ref> It is a giant double galaxy system pairing up with another elliptical galaxy UGC 8669 NED02<ref>{{Cite web |title=NED Search results for UGC 8669 NED02 |url=https://ned.ipac.caltech.edu/byname?objname=UGC+8669+NED02&hconst=67.8&omegam=0.308&omegav=0.692&wmap=4&corr_z=1 |access-date=2025-09-01 |website=NASA/IPAC Extragalactic Database}}</ref> or B2 1339+26A, to collectively form VV 5-32-63/64.<ref>{{Cite journal |last=Hintzen |first=P. |date=August 1979 |title=VV 5-32-63/64 - The 'supermassive double galaxy' in Abell 1775 revisited |url=https://iopscience.iop.org/article/10.1086/130514/pdf |journal=Publications of the Astronomical Society of the Pacific |volume=91 |pages=426 |doi=10.1086/130514 |issn=0004-6280}}</ref> The two nuclei of the system are estimated to display a [[radial velocity]] difference of 1700 kilometers per seconds with the separation of approximately 30 kiloparsecs from each other. The total mass of the system is 2 × 10<sup>13</sup> [[Solar mass|M<sub>☉</sub>]] making it somehow larger comparing to the low limit of double galaxies located in clusters.<ref name=":1">{{Cite journal |last1=Chincarini |first1=Guido |last2=Rood |first2=Herbert J. |last3=Sastry |first3=Gummuluru N. |last4=Welch |first4=Gary A. |date=August 1971 |title=A Supermassive Double Galaxy in the Cluster Abell 1775 |url=https://articles.adsabs.harvard.edu/pdf/1971ApJ...168...11C |journal=The Astrophysical Journal |language=en |volume=168 |pages=11 |doi=10.1086/151055 |bibcode=1971ApJ...168...11C |issn=0004-637X}}</ref> Both of the galaxies in the system display strong forms of [[Galaxy|isophotal]] twisting with [[Flattening|ellipticity]] variations, suggestive of a collision.<ref>{{Cite journal |last1=Hayes |first1=J. J. E. |last2=Bhattacharya |first2=B. |date=November 1990 |title=The cD galaxy in Abell cluster 1775. |url=https://articles.adsabs.harvard.edu//full/1990NASCP3098..195H/0000199.000.html |journal=NASA Conference Publication |language=en |volume=3098 |issue=124 |pages=195–199 |bibcode=1990NASCP3098..195H }}</ref>
The galaxy has head-tail [[Astronomical radio source|radio source]] with an extension of 380 [[Parsec|kiloparsecs]] in extent.<ref name=":0">{{Cite journal |last1=Botteon |first1=A. |last2=Giacintucci |first2=S. |last3=Gastaldello |first3=F. |last4=Venturi |first4=T. |last5=Brunetti |first5=G. |last6=Weeren |first6=R. J. van |last7=Shimwell |first7=T. W. |last8=Rossetti |first8=M. |last9=Akamatsu |first9=H. |last10=Brüggen |first10=M. |last11=Cassano |first11=R. |last12=Cuciti |first12=V. |last13=Gasperin |first13=F. de |last14=Drabent |first14=A. |last15=Hoeft |first15=M. |date=2021-05-01 |title=Nonthermal phenomena in the center of Abell 1775 - An 800 kpc head-tail, revived fossil plasma and slingshot radio halo |url=https://www.aanda.org/articles/aa/pdf/2021/05/aa40083-20.pdf |journal=Astronomy & Astrophysics |language=en |volume=649 |pages=A37 |doi=10.1051/0004-6361/202040083 |arxiv=2103.01989 |bibcode=2021A&A...649A..37B |issn=0004-6361}}</ref><ref>{{Cite journal |last1=Giacintucci |first1=S. |last2=Venturi |first2=T. |last3=Murgia |first3=M. |last4=Dallacasa |first4=D. |last5=Athreya |first5=R. |last6=Bardelli |first6=S. |last7=Mazzotta |first7=P. |last8=Saikia |first8=D. J. |date=2007-10-02 |title=Radio morphology and spectral analysis of cD galaxies in rich and poor galaxy clusters |url=https://www.aanda.org/articles/aa/pdf/2007/46/aa7918-07.pdf |journal=Astronomy & Astrophysics |language=en |volume=476 |issue=1 |pages=99–119 |doi=10.1051/0004-6361:20077918 |arxiv=0708.4330 |bibcode=2007A&A...476...99G |issn=0004-6361}}</ref> When imaged with [[Very Large Array]], it has a head component showing an innermost structure found detected as an off-centered nucleus with two [[Astrophysical jet|radio jets]] on opposite [[symmetry]]. The northeast jet is straight in the path of the tail direction while the southwest jet mainly displays a bend at 0.7 kiloparsecs. There is a radio core located southwards from a bright hotspot.<ref>{{Cite journal |last1=Gregory |first1=B. Terni de |last2=Feretti |first2=L. |last3=Giovannini |first3=G. |last4=Govoni |first4=F. |last5=Murgia |first5=M. |last6=Perley |first6=R. A. |last7=Vacca |first7=V. |date=2017-12-01 |title=Narrow head-tail radio galaxies at very high resolution |url=https://www.aanda.org/articles/aa/abs/2017/12/aa30878-17/aa30878-17.html |journal=Astronomy & Astrophysics |language=en |volume=608 |pages=A58 |doi=10.1051/0004-6361/201730878 |arxiv=1709.00223 |bibcode=2017A&A...608A..58T |issn=0004-6361}}</ref> The other galaxy B2 1339+26A has been classified as a double radio galaxy.<ref name=":0" />
Recent observations have showed the galaxy has an unexpected increase of [[surface brightness]] in some of the tail regions suggesting its jets display a complex bend. There was also evidence that the [[spectral index]] is rising in an unexpected manner for some of the regions ranging between 1.37 ± 0.14 and 0.88 ± 0.14. Because the regions are situated close to a fossil [[Plasma (physics)|plasma]] filament with an ultra-steep [[spectrum]], it is likely the [[Radio wave|radio emission]] is contaminating the galaxy.<ref>{{Cite journal |last1=Bushi |first1=A. |last2=Botteon |first2=A. |last3=Dallacasa |first3=D. |last4=Weeren |first4=R. J. van |last5=Venturi |first5=T. |last6=Brüggen |first6=M. |last7=Gastaldello |first7=F. |last8=Giacintucci |first8=S. |date=2025-02-01 |title=The head-tail radio galaxy and revived fossil plasma in Abell 1775 |url=https://www.aanda.org/articles/aa/abs/2025/02/aa53391-24/aa53391-24.html |journal=Astronomy & Astrophysics |language=en |volume=694 |pages=A317 |doi=10.1051/0004-6361/202453391 |arxiv=2502.04913 |bibcode=2025A&A...694A.317B |issn=0004-6361}}</ref>
A tail extension has been discovered in the galaxy making the source longer with a [[Collimated beam|collimated]] structure reaching up to 400 kiloparsecs, before breaking up and becoming diffused at the spot of a [[cold front]]. This might be suggested by dormant tail [[Electron|electrons]] displaying re-acceleration.<ref name=":0" />
== References == <references />
== External links == {{WikiSky}} *[http://simbad.u-strasbg.fr/simbad/sim-id?bibyear1=1850&bibyear2=%24currentYear&submit=Display&Ident=%402192475&Name=4C+26.41&bibdisplay=refsum&bibyear1=1850&bibyear2=%24currentYear#lab_bib UGC 8669 on SIMBAD]
{{Boötes}} [[Category:Radio galaxies]] [[Category:Boötes]] [[Category:Elliptical galaxies]] [[Category:Active galaxies]] [[Category:UGC objects|8669]] [[Category:MCG objects]] [[Category:Principal Galaxies Catalogue objects|048495]] [[Category:4C objects|26.41]] [[Category:Astronomical objects discovered in 1977]]