THE VERTICAL METALLICITY GRADIENT OF THE MILKY WAY DISK: TRANSITIONS IN [α/Fe] POPULATIONS

By K. Schlesinger, Jennifer A. Johnson, C. Rockosi, Y. S. Lee, Timothy C. Beers, P. Harding, C. Allende Prieto, J. Bird, R. Schoenrich, Brian Yanny and 3 more. 2014

25 citations recorded by the source corpus.

Using G dwarfs from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) survey, we have determined the vertical metallicity gradient in the Milky Way's disk and examined how this gradient varies for different [α/Fe] subsamples. Our sample contains over 40,000 stars with low-resolution spectroscopy over 144 lines of sight. It also covers a significant disk volume, between ∼0.3 and 1.6 kpc from the Galactic plane, and allows us to examine the disk in situ, whereas previous analyses were more limited in scope. Furthermore, this work does not presuppose a disk structure, whether composed of a single complex population or distinct thin and thick disk components. We employ the SEGUE Stellar Parameter Pipeline to obtain estimates of stellar parameters, [Fe/H], and [α/Fe] and extract multiple volume-complete subsamples of approximately 1000 stars each. Based on SEGUE's target-selection algorithm, we adjust each subsample to determine an unbiased picture of disk chemistry; consequently, each individual star represents the properties of many. The metallicity gradient is −0.243 dex kpc−1 for the entire sample, which we compare to various literature results. This gradient stems from the different [α/Fe] populations inhabiting different ranges of height above the Galactic plane. Each [α/Fe] subsample shows little change in median [Fe/H] with height. If we associate [α/Fe] with age, the negligible gradients of our [α/Fe] subsamples suggest that stars formed in different epochs exhibit comparable vertical structure, implying similar star formation processes and evolution.

Subfields: Astronomy and Astrophysics, Instrumentation

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Citations in the corpus

Yule-Simpson’s paradox in Galactic Archaeology (2019, background): “Depending on the observational biases of different dataset, different slopes in [Fe/H] (or [M/H]) with |z| would be measured in the total population as summarized by Schlesinger et al. (2014), which may result in different interpretations.”
Impacts of a flaring star-forming disc and stellar radial mixing on the vertical metallicity gradient (2016, background): “This seems consistent with the negligible vertical metallicity gradients for different samples of stars with similar [α/Fe] abundance ratios from SDSS/Sloan Extension for Galactic Understanding and Exploration (SEGUE) data (Schlesinger et al. 2014), if [α/Fe] is considered to be related to the age.”
CHEMICAL CARTOGRAPHY WITH APOGEE: METALLICITY DISTRIBUTION FUNCTIONS AND THE CHEMICAL STRUCTURE OF THE MILKY WAY DISK (2015, background): “…1982; Gilmore & Reid 1983), chemical abundance gradients (e.g., Hartkopf & Yoss 1982; Cheng et al. 2012b; Anders et al. 2014; Hayden et al. 2014; Schlesinger et al. 2014), and the G-dwarf problem (van den Bergh 1962; Pagel & Patchett 1975), from the study of the metallicity distribution…”
TRACING CHEMICAL EVOLUTION OVER THE EXTENT OF THE MILKY WAY'S DISK WITH APOGEE RED CLUMP STARS (2014, result): “This result is also in qualitative agreement with the vertical-scale-height measurements of Bovy et al. (2012b) and the verticalmetallicity-gradient measurements of Schlesinger et al. (2014) and Boeche et al. (2014).”
The vertical metallicity gradients of mono-age stellar populations in the Milky Way with the RAVE and Gaia data (2017, methodology): “Assuming [α/Fe] is a proxy for age, Schlesinger et al. (2014)’s results imply that mono-age stellar populations should have similarly negligible vertical metallicity gradients, in contradiction with the Xiang et al. (2015) result.”