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Life at the periphery of the Local Group: the kinematics of the Tucana dwarf galaxy


Fraternali, F and Tolstoy, E and Irwin, MJ and Cole, AA, Life at the periphery of the Local Group: the kinematics of the Tucana dwarf galaxy, Astronomy & Astrophysics, 499, (1) pp. 121-128. ISSN 0004-6361 (2009) [Refereed Article]

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Copyright 2008 EDP

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DOI: doi:10.1051/0004-6361/200810830


Aims. Dwarf spheroidal galaxies in the Local Group are usually located close to the Milky Way or M31. Currently, there are two clear exceptions to this rule, and the Tucana dwarf galaxy is the most distant at almost 1 Mpc from the MilkyWay. Our aim is to learn more about the nature of Tucana by measuring its radial velocity and internal kinematics. Methods. Using the VLT/FORS2 spectrograph in multi-object mode we were able to measure the velocities of 23 individual Red Giant Branch stars in and around Tucana using the Ca triplet absorption lines. From this sample, 17 reliable members have been identified. Conclusions. Our study firmly excludes any obvious association of Tucana with the HI emission in the vicinity and shows that Tucana is a genuine dwarf spheroidal, with low metallicity stars, no gaseous ISM and no recent star formation. The present location and relatively high recession velocity are consistent with Tucana having been an isolated Local Group galaxy for the majority of its existence.

Item Details

Item Type:Refereed Article
Keywords:galaxies:individual:Tucana dwarf-galaxies:structure-galaxies:kinematics and dynamics-galaxies:stellar content
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Cosmology and extragalactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Cole, AA (Associate Professor Andrew Cole)
ID Code:57517
Year Published:2009
Web of Science® Times Cited:72
Deposited By:Physics
Deposited On:2009-07-23
Last Modified:2011-03-22
Downloads:40 View Download Statistics

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