Variable stars in the Cetus dwarf spheroidal galaxy: population gradients and connections with the star formation history

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DOIResolve DOI: http://doi.org/10.1111/j.1365-2966.2012.20539.x
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TypeArticle
Journal titleMonthly Notices of the Royal Astronomical Society
ISSN0035-8711
Volume422
Issue1
Pages89105; # of pages: 17
AbstractWe investigate the variable star content of the isolated, Local Group, dwarf spheroidal (dSph) galaxy Cetus. Multi-epoch, wide-field images collected with the Very Large Telescope/Visible Multiobject Spectrograph camera allowed us to detect 638 variable stars (630 RRLyrae stars and eight anomalous Cepheids), 475 of which are new detections. We present a full catalogue of periods, amplitudes and mean magnitudes. Motivated by the recent discovery that the pulsational properties of the RRLyrae stars in the Tucana dSph revealed the presence of a metallicity gradient within the oldest (>rsim10Gyr old) stellar populations, we investigated the possibility of an analogous effect in Cetus. We found that, despite the obvious radial gradient in the horizontal branch and red giant branch morphologies, both becoming bluer on average for increasing distance from the centre of Cetus, the properties of the RRLyrae stars are homogeneous within the investigated area (out to r∼ 15arcmin), with no significant evidence of a radial gradient. We discuss this in connection with the star formation history previously derived for the two galaxies. The observed differences between these two systems show that even systems this small show a variety of early evolutionary histories. These differences could be due to different merger or accretion histories.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); National Science Infrastructure
Peer reviewedYes
NPARC number21270267
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Record identifiere8f68027-1dd5-4593-a919-b10f59efe1d8
Record created2014-01-17
Record modified2016-05-09
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