Skip to content
Back to outputs

The chemical properties of the Milky Way's on-bar and off-bar regions: evidence for inhomogeneous star formation history in the bulge

Research output: Contribution to journalArticlepeer-review

Standard

The chemical properties of the Milky Way's on-bar and off-bar regions : evidence for inhomogeneous star formation history in the bulge. / Lian, Jianhui; Zasowski, Gail; Hasselquist, Sten; Neumann, Justus; Majewski, Steven R.; Cohen, Roger E.; Fernández-Trincado, José G.; Lane, Richard R.; Longa-Peña, Peélope; Roman-Lopes, Alexandre.

In: Monthly Notices of the Royal Astronomical Society, 24.10.2020.

Research output: Contribution to journalArticlepeer-review

Harvard

Lian, J, Zasowski, G, Hasselquist, S, Neumann, J, Majewski, SR, Cohen, RE, Fernández-Trincado, JG, Lane, RR, Longa-Peña, P & Roman-Lopes, A 2020, 'The chemical properties of the Milky Way's on-bar and off-bar regions: evidence for inhomogeneous star formation history in the bulge', Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnras/staa3256

APA

Lian, J., Zasowski, G., Hasselquist, S., Neumann, J., Majewski, S. R., Cohen, R. E., Fernández-Trincado, J. G., Lane, R. R., Longa-Peña, P., & Roman-Lopes, A. (2020). The chemical properties of the Milky Way's on-bar and off-bar regions: evidence for inhomogeneous star formation history in the bulge. Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnras/staa3256

Vancouver

Lian J, Zasowski G, Hasselquist S, Neumann J, Majewski SR, Cohen RE et al. The chemical properties of the Milky Way's on-bar and off-bar regions: evidence for inhomogeneous star formation history in the bulge. Monthly Notices of the Royal Astronomical Society. 2020 Oct 24. https://doi.org/10.1093/mnras/staa3256

Author

Lian, Jianhui ; Zasowski, Gail ; Hasselquist, Sten ; Neumann, Justus ; Majewski, Steven R. ; Cohen, Roger E. ; Fernández-Trincado, José G. ; Lane, Richard R. ; Longa-Peña, Peélope ; Roman-Lopes, Alexandre. / The chemical properties of the Milky Way's on-bar and off-bar regions : evidence for inhomogeneous star formation history in the bulge. In: Monthly Notices of the Royal Astronomical Society. 2020.

Bibtex

@article{6af0e26088e04cef962ccf7f72a2c3f8,
title = "The chemical properties of the Milky Way's on-bar and off-bar regions: evidence for inhomogeneous star formation history in the bulge",
abstract = "Numerous studies of integrated starlight, stellar counts, and kinematics have confirmed that the Milky Way is a barred galaxy. However, far fewer studies have investigated the bar{\textquoteright}s stellar population properties, which carry valuable independent information regarding the bar{\textquoteright}s formation history. Here we conduct a detailed analysis of chemical abundance distributions ([Fe/H] and [Mg/Fe]) in the on-bar and off-bar regions to study the azimuthal variation of star formation history (SFH) in the inner Galaxy. We find that the on-bar and off-bar stars at Galactocentric radii 3 < rGC < 5 kpc have remarkably consistent [Fe/H] and [Mg/Fe] distribution functions and [Mg/Fe]–[Fe/H] relation, suggesting a common SFH shared by the long bar and the disc. In contrast, the bar and disc at smaller radii (2 < rGC < 3 kpc) show noticeable differences, with relatively more very metal-rich (⁠[Fe/H] ∼ 0.4) stars but fewer solar abundance stars in the bar. Given the three-phase star formation history proposed for the inner Galaxy in Lian et al. (2020c), these differences could be explained by the off-bar disc having experienced either a faster early quenching process or recent metal-poor gas accretion. Vertical variations of the abundance distributions at small rGC suggest a wider vertical distribution of low-α stars in the bar, which may serve as chemical evidence for vertical heating through the bar buckling process. The lack of such vertical variations outside the bulge may then suggest a lack of vertical heating in the long bar.",
keywords = "astro-ph.GA, astro-ph.SR, RCUK, STFC, ST/S000550/1, The Galaxy: abundances, The Galaxy: bulge, The Galaxy: formation, The Galaxy: evolution, The Galaxy: stellar content, The Galaxy: structure",
author = "Jianhui Lian and Gail Zasowski and Sten Hasselquist and Justus Neumann and Majewski, {Steven R.} and Cohen, {Roger E.} and Fern{\'a}ndez-Trincado, {Jos{\'e} G.} and Lane, {Richard R.} and Pe{\'e}lope Longa-Pe{\~n}a and Alexandre Roman-Lopes",
note = "9 pages, 5 figures. Submitted to MNRAS",
year = "2020",
month = oct,
day = "24",
doi = "10.1093/mnras/staa3256",
language = "English",
journal = "MNRAS",
issn = "0035-8711",
publisher = "Oxford University Press",

}

RIS

TY - JOUR

T1 - The chemical properties of the Milky Way's on-bar and off-bar regions

T2 - evidence for inhomogeneous star formation history in the bulge

AU - Lian, Jianhui

AU - Zasowski, Gail

AU - Hasselquist, Sten

AU - Neumann, Justus

AU - Majewski, Steven R.

AU - Cohen, Roger E.

AU - Fernández-Trincado, José G.

AU - Lane, Richard R.

AU - Longa-Peña, Peélope

AU - Roman-Lopes, Alexandre

N1 - 9 pages, 5 figures. Submitted to MNRAS

PY - 2020/10/24

Y1 - 2020/10/24

N2 - Numerous studies of integrated starlight, stellar counts, and kinematics have confirmed that the Milky Way is a barred galaxy. However, far fewer studies have investigated the bar’s stellar population properties, which carry valuable independent information regarding the bar’s formation history. Here we conduct a detailed analysis of chemical abundance distributions ([Fe/H] and [Mg/Fe]) in the on-bar and off-bar regions to study the azimuthal variation of star formation history (SFH) in the inner Galaxy. We find that the on-bar and off-bar stars at Galactocentric radii 3 < rGC < 5 kpc have remarkably consistent [Fe/H] and [Mg/Fe] distribution functions and [Mg/Fe]–[Fe/H] relation, suggesting a common SFH shared by the long bar and the disc. In contrast, the bar and disc at smaller radii (2 < rGC < 3 kpc) show noticeable differences, with relatively more very metal-rich (⁠[Fe/H] ∼ 0.4) stars but fewer solar abundance stars in the bar. Given the three-phase star formation history proposed for the inner Galaxy in Lian et al. (2020c), these differences could be explained by the off-bar disc having experienced either a faster early quenching process or recent metal-poor gas accretion. Vertical variations of the abundance distributions at small rGC suggest a wider vertical distribution of low-α stars in the bar, which may serve as chemical evidence for vertical heating through the bar buckling process. The lack of such vertical variations outside the bulge may then suggest a lack of vertical heating in the long bar.

AB - Numerous studies of integrated starlight, stellar counts, and kinematics have confirmed that the Milky Way is a barred galaxy. However, far fewer studies have investigated the bar’s stellar population properties, which carry valuable independent information regarding the bar’s formation history. Here we conduct a detailed analysis of chemical abundance distributions ([Fe/H] and [Mg/Fe]) in the on-bar and off-bar regions to study the azimuthal variation of star formation history (SFH) in the inner Galaxy. We find that the on-bar and off-bar stars at Galactocentric radii 3 < rGC < 5 kpc have remarkably consistent [Fe/H] and [Mg/Fe] distribution functions and [Mg/Fe]–[Fe/H] relation, suggesting a common SFH shared by the long bar and the disc. In contrast, the bar and disc at smaller radii (2 < rGC < 3 kpc) show noticeable differences, with relatively more very metal-rich (⁠[Fe/H] ∼ 0.4) stars but fewer solar abundance stars in the bar. Given the three-phase star formation history proposed for the inner Galaxy in Lian et al. (2020c), these differences could be explained by the off-bar disc having experienced either a faster early quenching process or recent metal-poor gas accretion. Vertical variations of the abundance distributions at small rGC suggest a wider vertical distribution of low-α stars in the bar, which may serve as chemical evidence for vertical heating through the bar buckling process. The lack of such vertical variations outside the bulge may then suggest a lack of vertical heating in the long bar.

KW - astro-ph.GA

KW - astro-ph.SR

KW - RCUK

KW - STFC

KW - ST/S000550/1

KW - The Galaxy: abundances

KW - The Galaxy: bulge

KW - The Galaxy: formation

KW - The Galaxy: evolution

KW - The Galaxy: stellar content

KW - The Galaxy: structure

U2 - 10.1093/mnras/staa3256

DO - 10.1093/mnras/staa3256

M3 - Article

JO - MNRAS

JF - MNRAS

SN - 0035-8711

ER -

ID: 22331938