CCAPP Seminar: Ivanna Escala (Caltech)

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Ivanna Escala Portrait
November 5, 2019
11:30AM - 12:30PM
Location
PRB 4138

Date Range
Add to Calendar 2019-11-05 11:30:00 2019-11-05 12:30:00 CCAPP Seminar: Ivanna Escala (Caltech) Ivanna Escala (Caltech) "Chemical Abundances in the Outer Disk, Giant Stellar Stream, and Inner Halo of Andromeda" Measurements of chemical abundances ([Fe/H] and [alpha/Fe]) in individual stars can probe the formation history of a galaxy. In contrast to the Milky Way, relatively little is known about [alpha/Fe] of individual red giant branch stars in Andromeda (M31). To make progress with existing telescopes, we have measured abundances from deep, low- and medium-resolution DEIMOS spectra of individual M31 RGB stars using spectral synthesis. I will present measurements of [alpha/Fe] and [Fe/H] for 91 M31 RGB stars across 5 fields spanning the inner halo, Giant Stellar Stream, and outer disk. Prior to our work, only 4 M31 halo stars had such measurements. I will discuss what the abundance distributions reveal about the progenitor(s) of M31’s halo, including the Giant Stellar Stream progenitor, and the formation of M31’s disk. PRB 4138 Center for Cosmology and AstroParticle Physics (CCAPP) ccapp@osu.edu America/New_York public
Description

Ivanna Escala (Caltech)

"Chemical Abundances in the Outer Disk, Giant Stellar Stream, and Inner Halo of Andromeda"

Measurements of chemical abundances ([Fe/H] and [alpha/Fe]) in individual stars can probe the formation history of a galaxy. In contrast to the Milky Way, relatively little is known about [alpha/Fe] of individual red giant branch stars in Andromeda (M31). To make progress with existing telescopes, we have measured abundances from deep, low- and medium-resolution DEIMOS spectra of individual M31 RGB stars using spectral synthesis. I will present measurements of [alpha/Fe] and [Fe/H] for 91 M31 RGB stars across 5 fields spanning the inner halo, Giant Stellar Stream, and outer disk. Prior to our work, only 4 M31 halo stars had such measurements. I will discuss what the abundance distributions reveal about the progenitor(s) of M31’s halo, including the Giant Stellar Stream progenitor, and the formation of M31’s disk.

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