SDSS-IV MaNGA: environmental dependence of gas metallicity gradients in local star-forming galaxies

Journal Article · 16 August 2019 · Monthly Notices of the Royal Astronomical Society

DOI: https://doi.org/10.1093/mnras/stz2218 · OSTI ID:1647664

Lian, Jianhui  ^[1]; Thomas, Daniel  ^[1]; Li, Cheng ^[2]; Zheng, Zheng ^[3]; Maraston, Claudia ^[1]; Bizyaev, Dmitry ^[4]; Lane, Richard R. ^[5]; Yan, Renbin  ^[6]

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1. Institute of Cosmology and Gravitation, University of Portsmouth, Burnaby Road, Portsmouth PO1 3FX, UK
2. Department of Astronomy, Tsinghua University, Beijing 100084, China
3. National Astronomical Observatories of China, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, China
4. Apache Point Observatory and New Mexico State University, PO Box 59, Sunspot, NM 88349-0059, USA, Sternberg Astronomical Institute, Moscow State University, 119992 Moscow, Russia
5. Instituto de Astrofisica, Pontificia Universidad Católica de Chile, Av. Vicuna Mackenna 4860, 782-0436 Macul, Santiago, Chile
6. Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, KY 40506, USA

ABSTRACT Within the standard model of hierarchical galaxy formation in a Λ cold dark matter universe, the environment of galaxies is expected to play a key role in driving galaxy formation and evolution. In this paper, we investigate whether and how the gas metallicity and the star formation surface density (ΣSFR) depend on galaxy environment. To this end, we analyse a sample of 1162 local, star-forming galaxies from the galaxy survey Mapping Nearby Galaxies at APO (MaNGA). Generally, both parameters do not show any significant dependence on environment. However, in agreement with previous studies, we find that low-mass satellite galaxies are an exception to this rule. The gas metallicity in these objects increases while their ΣSFR decreases slightly with environmental density. The present analysis of MaNGA data allows us to extend this to spatially resolved properties. Our study reveals that the gas metallicity gradients of low-mass satellites flatten and their ΣSFR gradients steepen with increasing environmental density. By extensively exploring a chemical evolution model, we identify two scenarios that are able to explain this pattern: metal-enriched gas accretion or pristine gas inflow with varying accretion time-scales. The latter scenario better matches the observed ΣSFR gradients, and is therefore our preferred solution. In this model, a shorter gas accretion time-scale at larger radii is required. This suggests that ‘outside–in quenching’ governs the star formation processes of low-mass satellite galaxies in dense environments.

• Sponsoring Organization: USDOE
• OSTI ID: 1647664
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Vol. 489 Journal Issue: 1; ISSN 0035-8711
• Publisher: Oxford University PressCopyright Statement
• Country of Publication: United Kingdom
• Language: English