View source for Boötes I

{{Short description|Galaxy in the constellation Boötes}}
{{Infobox Galaxy
| image = Boo_SDSS_enhanced.jpg
| caption = SDSS image of Boo I
| name = Boötes Dwarf Galaxy
| epoch = [[Epoch (astronomy)#Julian years and J2000|J2000]]
| type = dSph<ref name="Belokurovetal2006" />
| ra = {{RA|14|00|06}}<ref name="Belokurovetal2006" />
| dec = {{DEC|+14|30|00}} ± 15{{pprime}}<ref name="Belokurovetal2006" />
| dist_ly = [[1 E21 m|197 ± 18]] [[light-year|kly]] (60 ± 6 [[parsec|kpc]])<ref name="Belokurovetal2006" />
| z = 
| appmag_v = 13.1{{Ref_label|A|a|none}}
| size_v = 26.0{{prime}} ± 1.4{{prime}}<ref name="Belokurovetal2006" />
| constellation name = [[Boötes]]
| notes = 
| names = Boo dSph, Boötes Satellite, Boötes Dwarf Spheroidal Galaxy, Boötes dSph galaxy,<ref name="simbad">{{cite simbad
  | title=NAME Bootes Dwarf Spheroidal Galaxy
  | access-date=2006-12-20}}</ref> PGC 4713553
}}

The '''Boötes Dwarf Galaxy''' (''Boo I dSph'') is a [[galaxy]] discovered in 2006, which appears faint, with a [[luminosity]] of {{Solar luminosity|link=y|100,000}} and an [[absolute magnitude]] of –5.8. It lies about {{convert|197000|ly|kpc|1|abbr=off|lk=on}} away in the constellation [[Boötes]]. This [[dwarf spheroidal galaxy]] appears to be [[tidal disruption|tidally disrupted]]<ref name="Belokurovetal2006">{{cite journal
  | display-authors=4
  | author=Belokurov, V.
  | author2=Zucker, D. B.
  | author3=Evans, N. W.
  | author4=Wilkinson, M. I.
  | author5=Irwin, M. J.
  | author6=Hodgkin, S.
  | author7=Bramich, D. M.
  | author8=Irwin, J. M.
  | author9=Gilmore, G.
  | author10=Willman, B.
  | author11=Vidrih, S.
  | author12=Newberg, H. J.
  | author13=Wyse, R. F. G.
  | author14=Fellhauer, M.
  | author15=Hewett, P. C.
  | author16=Cole, N.
  | author17=Bell, E. F.
  | author18=Beers, T. C.
  | author19=Rockosi, C. M.
  | author20=Yanny, B.
  | author21=Grebel, E. K.
  | author22=Schneider, D. P.
  | author23=Lupton, R.
  | author24=Barentine, J. C.
  | author25=Brewington, H.
  | author26=Brinkmann, J.
  | author27=Harvanek, M.
  | author28=Kleinman, S. J.
  | author29=Krzesinski, J.
  | author30=Long, D.
  | author31=Nitta, A.
  | author32=Smith, J. A.
  | author33=Snedden, S. A.
  | title=A Faint New Milky Way Satellite in Bootes
  | journal=The Astrophysical Journal
  | date=2006
  | volume=647
  | issue=2
  | pages=L111–L114
  | bibcode=2006ApJ...647L.111B
  | doi=10.1086/507324
  |arxiv = astro-ph/0604355 | s2cid=15348323
 }}</ref> by the [[Milky Way]] Galaxy, which [[Satellite galaxy|it orbits]], and has two stellar tails that cross over to form a cross.{{Citation needed|date=February 2007}} Tidally disrupted galaxies usually only form one tail.{{Citation needed|date=February 2007}} The galaxy appears to be significantly elongated, with an ellipticity of {{nowrap|ε {{=}} 0.68 ± 0.15}}.<ref>{{cite journal |doi=10.1093/mnras/stac1827 |bibcode=2022MNRAS.516.2348L |arxiv=2107.10849 |title=The Pristine dwarf galaxy survey – IV. Probing the outskirts of the dwarf galaxy Boötes I |year=2022 |last1=Longeard |first1=Nicolas |last2=Jablonka |first2=Pascale |last3=Arentsen |first3=Anke |last4=Thomas |first4=Guillaume F. |last5=Aguado |first5=David S. |last6=Carlberg |first6=Raymond G. |last7=Lucchesi |first7=Romain |last8=Malhan |first8=Khyati |last9=Martin |first9=Nicolas |last10=McConnachie |first10=Alan W. |last11=Navarro |first11=Julio F. |last12=Sánchez-Janssen |first12=Rubén |last13=Sestito |first13=Federico |last14=Starkenburg |first14=Else |last15=Yuan |first15=Zhen |journal=Monthly Notices of the Royal Astronomical Society |volume=516 |issue=2 |pages=2348–2362 |doi-access=free }}</ref>

Like many of the ultrafaint dwarf spheroidals, the entire galaxy appears fainter than the [[Rigel]] system (absolute magnitude –7.84).<ref name=schultz>{{cite journal|bibcode=2014MNRAS.438.1114S|arxiv=1311.5116|title=An observational evaluation of magnetic confinement in the winds of BA supergiants|journal=Monthly Notices of the Royal Astronomical Society|volume=438|issue=2|pages=1114|last1=Shultz|first1=M.|last2=Wade|first2=G. A.|last3=Petit|first3=V.|last4=Grunhut|first4=J.|last5=Neiner|first5=C.|last6=Hanes|first6=D.|author7=MiMeS Collaboration|year=2014|doi=10.1093/mnras/stt2260|doi-access=free }}</ref> Even so, it is one of the more luminous UFDs.<ref name=Jenkins>{{cite journal|doi=10.3847/1538-4357/ac1353 |arxiv=2101.00013|title=Very Large Telescope Spectroscopy of Ultra-faint Dwarf Galaxies. I. Boötes I, Leo IV, and Leo V|year=2021|last1=Jenkins|first1=Sydney A.|last2=Li|first2=Ting S.|last3=Pace|first3=Andrew B.|last4=Ji|first4=Alexander P.|last5=Koposov|first5=Sergey E.|last6=Mutlu-Pakdil|first6=Burçin|journal=The Astrophysical Journal|volume=920|issue=2|page=92|bibcode=2021ApJ...920...92J |s2cid=230433692 |doi-access=free }}</ref> It is metal-poor, like other UFDs, with a mean [[metallicity]] of −2.34.<ref name=Jenkins/>

The stellar population of Boötes I is mostly very old stars. The two populations have essentially the same age, 13.4 billion and 13.3 billion years, respectively, with most of the stars being of the latter population.<ref>{{cite journal|doi=10.1088/0004-637X/796/2/91|title=The Quenching of the Ultra-Faint Dwarf Galaxies in the Reionization Era|year=2014|last1=Brown|first1=Thomas M.|last2=Tumlinson|first2=Jason|last3=Geha|first3=Marla|author3-link= Marla Geha |last4=Simon|first4=Joshua D.|last5=Vargas|first5=Luis C.|last6=Vandenberg|first6=Don A.|last7=Kirby|first7=Evan N.|last8=Kalirai|first8=Jason S.|last9=Avila|first9=Roberto J.|last10=Gennaro|first10=Mario|last11=Ferguson|first11=Henry C.|last12=Muñoz|first12=Ricardo R.|last13=Guhathakurta|first13=Puragra|last14=Renzini|first14=Alvio|journal=The Astrophysical Journal|volume=796|issue=2|page=91|arxiv=1410.0681 |bibcode=2014ApJ...796...91B |s2cid=10097277|url=https://authors.library.caltech.edu/53098/}}</ref>

== Notes ==
{{refbegin}}
<ol type="a">
<li>{{Note_label|A|a|none}}[[Apparent magnitude]] = [[Absolute magnitude]] + [[Distance modulus]] = –5.8<ref name="Belokurovetal2006" /> + 18.9<ref name="Belokurovetal2006" /> = 13.1</li>
</ol>
{{refend}}

==References==
{{reflist}}

==External links==
* [http://www.atlasoftheuniverse.com/sattelit.html The Universe within 500,000 light-years The Satellite Galaxies] (Atlas of the Universe)
* [http://kencroswell.com/BootesCanesVenaticiDwarfs.html Two New Galaxies Orbiting the Milky Way] (Ken Croswell) April 19, 2006
* [http://www.newscientistspace.com/article/dn9043-strange-satellite-galaxies-revealed-around-milky-way.html Strange satellite galaxies revealed around Milky Way] Kimm Groshong (New Scientist) 17:00 24 April 2006
* [http://www.sdss.org/news/releases/20060508.companions.html New Milky Way companions found: SDSS-II first to view two dim dwarf galaxies] (SDSS) May 8, 2006
* [http://www.spacedaily.com/reports/Astronomers_Find_Two_New_Milky_Way_Companions.html Astronomers Find Two New Milky Way Companions] (SpaceDaily) May 10, 2006
* [http://www.constellation-guide.com/bootes-dwarf-galaxy-bootes-i/ Boötes Dwarf Galaxy at Constellation Guide]


{{Milky Way}}
{{Boötes}}
{{Sky|14|00|06|+|14|30|00|197000}}

{{DEFAULTSORT:Bootes 1}}
[[Category:Dwarf spheroidal galaxies]]
[[Category:Local Group]]
[[Category:Milky Way Subgroup]]
[[Category:Boötes]]
[[Category:Principal Galaxies Catalogue objects|4713553]]