View : 30 Download: 0

Asymmetric Mean Metallicity Distribution of the Milky Way's Disk

Title
Asymmetric Mean Metallicity Distribution of the Milky Way's Disk
Authors
An, Deokkeun
Ewha Authors
안덕근
SCOPUS Author ID
안덕근scopus
Issue Date
2019
Journal Title
ASTROPHYSICAL JOURNAL LETTERS
ISSN
2041-8205JCR Link

2041-8213JCR Link
Citation
ASTROPHYSICAL JOURNAL LETTERS vol. 878, no. 2
Keywords
Galaxy: abundancesGalaxy: diskGalaxy: structurestars: abundances
Publisher
IOP PUBLISHING LTD
Indexed
SCI; SCIE; SCOPUS WOS
Document Type
Article
Abstract
I present the mean metallicity distribution of stars in the Milky Way based on photometry from the Sloan Digital Sky Survey. I utilize an empirically calibrated set of stellar isochrones developed in previous work to estimate the metallicities of individual stars to a precision of 0.2 dex for reasonably bright stars across the survey area. I also obtain more precise metallicity estimates using priors from the Gaia parallaxes for relatively nearby stars. Close to the Galactic mid-plane (vertical bar Z vertical bar < 2 kpc), a mean metallicity map reveals deviations from the mirror symmetry between the northern and southern hemispheres, displaying wave-like oscillations. The observed metallicity asymmetry structure is almost parallel to the Galactic mid-plane, and coincides with the previously known asymmetry in the stellar number density distribution. This result reinforces the previous notion of the plane-parallel vertical waves propagating through the disk, in which a local metallicity perturbation from the mean vertical metallicity gradient is induced by the phase-space wrapping of stars in the Z-V-Z plane. The maximum amplitude of the metallicity asymmetry (Delta[Fe/H] similar to 0.05) implies that these stars have been pulled away from the Galactic mid-plane by an order of Delta vertical bar Z vertical bar similar to 80 pc as a massive halo substructure such as the Sagittarius dwarf galaxy plunged through the Milky Way. This work provides evidence that the Gaia phase-space spiral may continue out to vertical bar Z vertical bar similar to 1.5 kpc.
DOI
10.3847/2041-8213/ab2467
Appears in Collections:
사범대학 > 과학교육과 > Journal papers
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE