A curious Milky Way satellite in Ursa Major

D. B. Zucker; V. Belokurov; N. W. Evans; J. T. Kleyna; M. J. Irwin; M. I. Wilkinson; M. Fellhauer; D. M. Bramich; G. Gilmore; H. J. Newberg; B. Yanny; J. A. Smith; P. C. Hewett; E. F. Bell; H. W. Rix; O. Y. Gnedin; S. Vidrih; R. F.G. Wyse; B. Willman; E. K. Grebel; D. P. Schneider; T. C. Beers; A. Y. Kniazev; J. C. Barentine; H. Brewington; J. Brinkmann; M. Harvanek; S. J. Kleinman; J. Krzesinski; D. Long; A. Nitta; S. A. Snedden

doi:10.1086/508628

A curious Milky Way satellite in Ursa Major

D. B. Zucker
, V. Belokurov
, N. W. Evans
, J. T. Kleyna
, M. J. Irwin
, M. I. Wilkinson
, M. Fellhauer
, D. M. Bramich
, G. Gilmore
, H. J. Newberg
, B. Yanny
, J. A. Smith
, P. C. Hewett
, E. F. Bell
, H. W. Rix
, O. Y. Gnedin
, S. Vidrih
, R. F.G. Wyse
, B. Willman
, E. K. Grebel

D. P. Schneider, T. C. Beers, A. Y. Kniazev, J. C. Barentine, H. Brewington, J. Brinkmann, M. Harvanek, S. J. Kleinman, J. Krzesinski, D. Long, A. Nitta, S. A. Snedden

Research output: Contribution to journal › Article › peer-review

286 Scopus citations

Abstract

In this Letter, we study a localized stellar overdensity in the constellation of Ursa Major, first identified in Sloan Digital Sky Survey (SDSS) data and subsequently followed up with Subaru imaging. Its color-magnitude diagram (CMD) shows a well-defined subgiant branch, main sequence, and turnoff, from which we estimate a distance of ∼30 kpc and a projected size of ∼250 × 125 pc². The CMD suggests a composite population with some range in metallicity and/or age. Based on its extent and stellar population, we argue that this is a previously unknown satellite galaxy of the Milky Way, hereby named Ursa Major II (UMa II) after its constellation. Using SDSS data, we find an absolute magnitude of M_v ∼ -3.8, which would make it the faintest known satellite galaxy. UMa II's isophotes are irregular and distorted with evidence for multiple concentrations; this suggests that the satellite is in the process of disruption.

Original language	English (US)
Pages (from-to)	L41-L44
Journal	Astrophysical Journal
Volume	650
Issue number	1 II
DOIs	https://doi.org/10.1086/508628
State	Published - Oct 10 2006

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/508628

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Zucker, D. B., Belokurov, V., Evans, N. W., Kleyna, J. T., Irwin, M. J., Wilkinson, M. I., Fellhauer, M., Bramich, D. M., Gilmore, G., Newberg, H. J., Yanny, B., Smith, J. A., Hewett, P. C., Bell, E. F., Rix, H. W., Gnedin, O. Y., Vidrih, S., Wyse, R. F. G., Willman, B., ... Snedden, S. A. (2006). A curious Milky Way satellite in Ursa Major. Astrophysical Journal, 650(1 II), L41-L44. https://doi.org/10.1086/508628

@article{4d0d2165c7964b328caa0865e0739b8d,

title = "A curious Milky Way satellite in Ursa Major",

abstract = "In this Letter, we study a localized stellar overdensity in the constellation of Ursa Major, first identified in Sloan Digital Sky Survey (SDSS) data and subsequently followed up with Subaru imaging. Its color-magnitude diagram (CMD) shows a well-defined subgiant branch, main sequence, and turnoff, from which we estimate a distance of ∼30 kpc and a projected size of ∼250 × 125 pc2. The CMD suggests a composite population with some range in metallicity and/or age. Based on its extent and stellar population, we argue that this is a previously unknown satellite galaxy of the Milky Way, hereby named Ursa Major II (UMa II) after its constellation. Using SDSS data, we find an absolute magnitude of Mv ∼ -3.8, which would make it the faintest known satellite galaxy. UMa II's isophotes are irregular and distorted with evidence for multiple concentrations; this suggests that the satellite is in the process of disruption.",

author = "Zucker, \{D. B.\} and V. Belokurov and Evans, \{N. W.\} and Kleyna, \{J. T.\} and Irwin, \{M. J.\} and Wilkinson, \{M. I.\} and M. Fellhauer and Bramich, \{D. M.\} and G. Gilmore and Newberg, \{H. J.\} and B. Yanny and Smith, \{J. A.\} and Hewett, \{P. C.\} and Bell, \{E. F.\} and Rix, \{H. W.\} and Gnedin, \{O. Y.\} and S. Vidrih and Wyse, \{R. F.G.\} and B. Willman and Grebel, \{E. K.\} and Schneider, \{D. P.\} and Beers, \{T. C.\} and Kniazev, \{A. Y.\} and Barentine, \{J. C.\} and H. Brewington and J. Brinkmann and M. Harvanek and Kleinman, \{S. J.\} and J. Krzesinski and D. Long and A. Nitta and Snedden, \{S. A.\}",

note = "Funding Information: D. B. Z., V. B., M. I. W., M. F., and D. M. B. acknowledge the financial support of PPARC. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, Funding Information: the US Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web site is http://www.sdss.org.",

year = "2006",

month = oct,

day = "10",

doi = "10.1086/508628",

language = "English (US)",

volume = "650",

pages = "L41--L44",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "1 II",

}

Zucker, DB, Belokurov, V, Evans, NW, Kleyna, JT, Irwin, MJ, Wilkinson, MI, Fellhauer, M, Bramich, DM, Gilmore, G, Newberg, HJ, Yanny, B, Smith, JA, Hewett, PC, Bell, EF, Rix, HW, Gnedin, OY, Vidrih, S, Wyse, RFG, Willman, B, Grebel, EK, Schneider, DP, Beers, TC, Kniazev, AY, Barentine, JC, Brewington, H, Brinkmann, J, Harvanek, M, Kleinman, SJ, Krzesinski, J, Long, D, Nitta, A & Snedden, SA 2006, 'A curious Milky Way satellite in Ursa Major', Astrophysical Journal, vol. 650, no. 1 II, pp. L41-L44. https://doi.org/10.1086/508628

TY - JOUR

T1 - A curious Milky Way satellite in Ursa Major

AU - Zucker, D. B.

AU - Belokurov, V.

AU - Evans, N. W.

AU - Kleyna, J. T.

AU - Irwin, M. J.

AU - Wilkinson, M. I.

AU - Fellhauer, M.

AU - Bramich, D. M.

AU - Gilmore, G.

AU - Newberg, H. J.

AU - Yanny, B.

AU - Smith, J. A.

AU - Hewett, P. C.

AU - Bell, E. F.

AU - Rix, H. W.

AU - Gnedin, O. Y.

AU - Vidrih, S.

AU - Wyse, R. F.G.

AU - Willman, B.

AU - Grebel, E. K.

AU - Schneider, D. P.

AU - Beers, T. C.

AU - Kniazev, A. Y.

AU - Barentine, J. C.

AU - Brewington, H.

AU - Brinkmann, J.

AU - Harvanek, M.

AU - Kleinman, S. J.

AU - Krzesinski, J.

AU - Long, D.

AU - Nitta, A.

AU - Snedden, S. A.

N1 - Funding Information: D. B. Z., V. B., M. I. W., M. F., and D. M. B. acknowledge the financial support of PPARC. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, Funding Information: the US Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web site is http://www.sdss.org.

PY - 2006/10/10

Y1 - 2006/10/10

N2 - In this Letter, we study a localized stellar overdensity in the constellation of Ursa Major, first identified in Sloan Digital Sky Survey (SDSS) data and subsequently followed up with Subaru imaging. Its color-magnitude diagram (CMD) shows a well-defined subgiant branch, main sequence, and turnoff, from which we estimate a distance of ∼30 kpc and a projected size of ∼250 × 125 pc2. The CMD suggests a composite population with some range in metallicity and/or age. Based on its extent and stellar population, we argue that this is a previously unknown satellite galaxy of the Milky Way, hereby named Ursa Major II (UMa II) after its constellation. Using SDSS data, we find an absolute magnitude of Mv ∼ -3.8, which would make it the faintest known satellite galaxy. UMa II's isophotes are irregular and distorted with evidence for multiple concentrations; this suggests that the satellite is in the process of disruption.

AB - In this Letter, we study a localized stellar overdensity in the constellation of Ursa Major, first identified in Sloan Digital Sky Survey (SDSS) data and subsequently followed up with Subaru imaging. Its color-magnitude diagram (CMD) shows a well-defined subgiant branch, main sequence, and turnoff, from which we estimate a distance of ∼30 kpc and a projected size of ∼250 × 125 pc2. The CMD suggests a composite population with some range in metallicity and/or age. Based on its extent and stellar population, we argue that this is a previously unknown satellite galaxy of the Milky Way, hereby named Ursa Major II (UMa II) after its constellation. Using SDSS data, we find an absolute magnitude of Mv ∼ -3.8, which would make it the faintest known satellite galaxy. UMa II's isophotes are irregular and distorted with evidence for multiple concentrations; this suggests that the satellite is in the process of disruption.

UR - https://www.scopus.com/pages/publications/33751392781

UR - https://www.scopus.com/pages/publications/33751392781#tab=citedBy

U2 - 10.1086/508628

DO - 10.1086/508628

M3 - Article

AN - SCOPUS:33751392781

SN - 0004-637X

VL - 650

SP - L41-L44

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1 II

ER -

A curious Milky Way satellite in Ursa Major

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