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. GrebelD. 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

^*Corresponding author for this work

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

279 Citations (Scopus)

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
Pages (from-to)	L41-L44
Number of pages	4
Journal	Astrophysical Journal
Volume	650
Issue number	1
DOIs	https://doi.org/10.1086/508628
Publication status	Published - 10 Oct 2006
Externally published	Yes

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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), L41-L44. https://doi.org/10.1086/508628

@article{570cd0910a99475ebf20b5cf4fe4cd6c,

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.}",

year = "2006",

month = oct,

day = "10",

doi = "10.1086/508628",

language = "English",

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journal = "Astrophysical Journal",

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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, 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.

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.

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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

ER -

A curious Milky Way satellite in Ursa Major

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