Title of article :
Pulsating red giant and supergiant stars in the Local Group dwarf galaxy Andromeda I
Author/Authors :
Saremi, Elham Department of Physics - Faculty of Science - University of Birjand , Abedi, Abbas Department of Physics - Faculty of Science - University of Birjand , Javadi, Atefeh School of Astronomy - Institute for Research in Fundamental Sciences (IPM), Tehran , Loon, Jacco van Lennard-Jones Laboratories - Keele University, UK , Khosroshahi, Habib Department of Physics - Faculty of Science - University of Birjand
Abstract :
We have conducted an optical long-term monitoring survey of the majority
of dwarf galaxies in the Local Group, with the Isaac Newton Telescope (INT), to identify
the long period variable (LPV) stars. LPV stars vary on timescales of months to years,
and reach the largest amplitudes of their brightness variations at optical wavelengths,
due to the changing temperature. They trace stellar populations as young as ~ 30 Myr
to as old as ~ 10 Gyr whose identification is one of the best ways to reconstruct the
star formation history.
The system of galactic satellites of the large Andromeda spiral galaxy (M 31) forms one
of the key targets of our monitoring survey. In this first paper in the series, we present
the first results from the survey in the form of a census of LPV stars in Andromeda I
(And I) dwarf galaxy.
Photometry was obtained for 10585 stars in a 0.07 square degree field, of which 116 stars
were found to be variable, most of which are Asymptotic Giant Branch (AGB) stars.
Our data were matched to mid-infrared photometry from the Spitzer Space Telescope,
and to optical catalogues of variable stars from the Hubble Space Telescope.
Keywords :
stars , evolution , stars , red giants , supergiants , stars , mass-loss , stars , oscillations , galaxies , individual , Andromeda I , galaxies , stellar content
Journal title :
Astroparticle Physics
