Elemental Abundances in M31: The Kinematics and Chemical Evolution of Dwarf Spheroidal Satellite Galaxies. (arXiv:1912.02186v1 [astro-ph.GA])

Elemental Abundances in M31: The Kinematics and Chemical Evolution of Dwarf Spheroidal Satellite Galaxies. (arXiv:1912.02186v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Kirby_E/0/1/0/all/0/1">Evan N. Kirby</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Gilbert_K/0/1/0/all/0/1">Karoline M. Gilbert</a> (2 and 3), <a href="http://arxiv.org/find/astro-ph/1/au:+Escala_I/0/1/0/all/0/1">Ivanna Escala</a> (1 and 4), <a href="http://arxiv.org/find/astro-ph/1/au:+Wojno_J/0/1/0/all/0/1">Jennifer Wojno</a> (3), <a href="http://arxiv.org/find/astro-ph/1/au:+Guhathakurta_P/0/1/0/all/0/1">Puragra Guhathakurta</a> (5), <a href="http://arxiv.org/find/astro-ph/1/au:+Majewski_S/0/1/0/all/0/1">Steven R. Majewski</a> (6), <a href="http://arxiv.org/find/astro-ph/1/au:+Beaton_R/0/1/0/all/0/1">Rachael L. Beaton</a> (4 and 7) ((1) Caltech, (2) Space Telescope Science Institute, (3) Johns Hopkins, (4) Princeton, (5) UC Santa Cruz, (6) University of Virginia, (7) Carnegie Observatories)

We present deep spectroscopy from Keck/DEIMOS of Andromeda I, III, V, VII,
and X, all of which are dwarf spheroidal satellites of M31. The sample includes
256 spectroscopic members across all five dSphs. We confirm previous
measurements of the velocity dispersions and dynamical masses, and we provide
upper limits on bulk rotation. Our measurements confirm that M31 satellites
obey the same relation between stellar mass and stellar metallicity as Milky
Way (MW) satellites and other dwarf galaxies in the Local Group. The
metallicity distributions show similar trends with stellar mass as MW
satellites, including evidence in massive satellites for external influence,
like pre-enrichment or gas accretion. We present the first measurements of
individual element ratios, like [Si/Fe], in the M31 system, as well as
measurements of the average [alpha/Fe] ratio. The trends of [alpha/Fe] with
[Fe/H] also follow the same galaxy mass-dependent patterns as MW satellites.
Less massive galaxies have more steeply declining slopes of [alpha/Fe] that
begin at lower [Fe/H]. Finally, we compare the chemical evolution of M31
satellites to M31’s Giant Stellar Stream and smooth halo. The properties of the
M31 system support the theoretical prediction that the inner halo is composed
primarily of massive galaxies that were accreted early. As a result, the inner
halo exhibits higher [Fe/H] and [alpha/Fe] than surviving satellite galaxies.

We present deep spectroscopy from Keck/DEIMOS of Andromeda I, III, V, VII,
and X, all of which are dwarf spheroidal satellites of M31. The sample includes
256 spectroscopic members across all five dSphs. We confirm previous
measurements of the velocity dispersions and dynamical masses, and we provide
upper limits on bulk rotation. Our measurements confirm that M31 satellites
obey the same relation between stellar mass and stellar metallicity as Milky
Way (MW) satellites and other dwarf galaxies in the Local Group. The
metallicity distributions show similar trends with stellar mass as MW
satellites, including evidence in massive satellites for external influence,
like pre-enrichment or gas accretion. We present the first measurements of
individual element ratios, like [Si/Fe], in the M31 system, as well as
measurements of the average [alpha/Fe] ratio. The trends of [alpha/Fe] with
[Fe/H] also follow the same galaxy mass-dependent patterns as MW satellites.
Less massive galaxies have more steeply declining slopes of [alpha/Fe] that
begin at lower [Fe/H]. Finally, we compare the chemical evolution of M31
satellites to M31’s Giant Stellar Stream and smooth halo. The properties of the
M31 system support the theoretical prediction that the inner halo is composed
primarily of massive galaxies that were accreted early. As a result, the inner
halo exhibits higher [Fe/H] and [alpha/Fe] than surviving satellite galaxies.

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