On the newly discovered Canes Venatici II dSph galaxy

C. Greco; M. Dall'Ora; G. Clementini; V. Ripepi; L. Di Fabrizio; K. Kinemuchi; M. Marconi; I. Musella; H. A. Smith; C. T. Rodgers; C. Kuehn; T. C. Beers; M. Catelan; B. J. Pritzl

doi:10.1086/533585

arXiv · 0712.2241

On the newly discovered Canes Venatici II dSph galaxy

C. Greco·M. Dall'Ora·G. Clementini·V. Ripepi·L. Di Fabrizio·K. Kinemuchi·M. Marconi·I. Musella·H. A. Smith·C. T. Rodgers·C. Kuehn·T. C. Beers·M. Catelan·B. J. Pritzl

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Abstract

We report on the detection of variable stars in the Canes Venatici II (CVn II) dwarf spheroidal galaxy, a new satellite of the Milky Way recently discovered by the Sloan Digital Sky Survey. We also present a V, B-V color-magnitude diagram that reaches V = 25.5 mag, showing the galaxy's main sequence turn off at V = 24.5 mag and revealing several candidate blue straggler stars. Two RR Lyrae stars have been identified within the half-light radius of CVn II,a fundamental-mode variable (RRab) with period P_ab = 0.743 days, and a first-overtone (RRc) RR Lyrae star with P_c = 0.358 days. The rather long periods of these variables along with their position on the period-amplitude diagram support an Oosterhoff type II classification for CVn II. The average apparent magnitude of the RR Lyrae stars, = 21.48 +/- 0.02 mag, is used to obtain a precision distance modulus of mu_0 = 21.02 +/- 0.06 mag and a corresponding distance of 160(+4,-5} kpc, for an adopted reddening E(B-V) = 0.015 mag.

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C. Greco, M. Dall'Ora, G. Clementini, V. Ripepi, L. Di Fabrizio, K. Kinemuchi, M. Marconi, I. Musella, H. A. Smith, C. T. Rodgers, C. Kuehn, T. C. Beers, M. Catelan, B. J. Pritzl. 2007-12-13. On the newly discovered Canes Venatici II dSph galaxy. https://doi.org/10.1086/533585

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