Journal Article

Chemodynamical analysis of bulge stars for simulated disc galaxies

A. Rahimi, D. Kawata, Chris B. Brook and Brad K. Gibson

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 401, issue 3, pages 1826-1831
Published in print January 2010 | ISSN: 0035-8711
Published online January 2010 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2009.15752.x
Chemodynamical analysis of bulge stars for simulated disc galaxies

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We analyse the kinematics and chemistry of the bulge stars of two simulated disc galaxies using our chemodynamical galaxy evolution code gcd+. First, we compare stars that are born inside the galaxy with those that are born outside the galaxy and are accreted into the centre of the galaxy. Stars that originate outside the bulge are accreted into it early in its formation within 3 Gyr so that these stars have high [α/Fe] as well as a high total energy reflecting their accretion to the centre of the galaxy. Therefore, higher total energy is a good indicator for finding accreted stars. The bulges of the simulated galaxies formed through multiple mergers separated by about a Gyr. Since [α/Fe] is sensitive to the first few Gyr of star formation history, stars that formed during mergers at different epochs show different [α/Fe]. We show that the [Mg/Fe] against star formation time relation can be very useful to identify a multiple merger bulge formation scenario, provided there is sufficiently good age information available. Our simulations also show that stars formed during one of the merger events retain a systematically prograde rotation at the final time. This demonstrates that the orbit of the ancient merger that helped to form the bulge could still remain in the kinematics of bulge stars.

Keywords: Galaxy: bulge; Galaxy: kinematics and dynamics; galaxies: evolution; galaxies: formation; galaxies: interactions

Journal Article.  4728 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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