TY - JOUR

T1 - The origin of the dust extinction curve in milky way-like galaxies

AU - Li, Qi

AU - Narayanan, Desika

AU - Torrey, Paul

AU - Dave, Romeel

AU - Vogelsberger, Mark

PY - 2021/10

Y1 - 2021/10

N2 - We develop a cosmological model for the evolution of dust grains in galaxies with a distribution of sizes in order to understand the origin of the Milky Way dust extinction curve. Our model considers the formation of active dust in evolved stars, growth by accretion and coagulation, and destruction processes via shattering, sputtering, and astration in the ISM of galaxies over cosmic time. Our main results follow. Galaxies in our cosmological model with masses comparable to the Milky Way's at z similar to 0 exhibit a diverse range of extinction laws, though with slopes and bump strengths comparable to the range observed in the Galaxy. The progenitors of the Milky Way have steeper slopes, and only flatten to slopes comparable to the Galaxy at z similar to 1. This owes to increased grain growth rates at late times/in high-metallicity environments driving up the ratio of large to small grains, with a secondary dependence on the graphite-to-silicate ratio evolution. The UV bump strengths depend primarily on the graphite-to-silicate ratio, and remain broadly constant in MW-like galaxies between z = 3 and z = 0, though show slight variability. Our models span comparable regions of bump-slope space as sightlines in the Galaxy do, though there is a lack of clear relationship between the model slopes and bump strengths owing to variations among galaxies in the graphite-to-silicate ratio. Our model provides a novel framework to study the origins and variations of dust extinction curves in galaxies over cosmic time.

AB - We develop a cosmological model for the evolution of dust grains in galaxies with a distribution of sizes in order to understand the origin of the Milky Way dust extinction curve. Our model considers the formation of active dust in evolved stars, growth by accretion and coagulation, and destruction processes via shattering, sputtering, and astration in the ISM of galaxies over cosmic time. Our main results follow. Galaxies in our cosmological model with masses comparable to the Milky Way's at z similar to 0 exhibit a diverse range of extinction laws, though with slopes and bump strengths comparable to the range observed in the Galaxy. The progenitors of the Milky Way have steeper slopes, and only flatten to slopes comparable to the Galaxy at z similar to 1. This owes to increased grain growth rates at late times/in high-metallicity environments driving up the ratio of large to small grains, with a secondary dependence on the graphite-to-silicate ratio evolution. The UV bump strengths depend primarily on the graphite-to-silicate ratio, and remain broadly constant in MW-like galaxies between z = 3 and z = 0, though show slight variability. Our models span comparable regions of bump-slope space as sightlines in the Galaxy do, though there is a lack of clear relationship between the model slopes and bump strengths owing to variations among galaxies in the graphite-to-silicate ratio. Our model provides a novel framework to study the origins and variations of dust extinction curves in galaxies over cosmic time.

KW - (ISM:) dust

KW - extinction

KW - galaxies: evolution

KW - galaxies: ISM

KW - GRAIN-SIZE DISTRIBUTION

KW - INTERSTELLAR DUST

KW - ULTRAVIOLET EXTINCTION

KW - COSMOLOGICAL SIMULATIONS

KW - MAGELLANIC-CLOUD

KW - EVOLUTION

KW - GAS

KW - MASS

KW - SHAPES

KW - GROWTH

U2 - 10.1093/mnras/stab2196

DO - 10.1093/mnras/stab2196

M3 - Journal article

VL - 507

SP - 548

EP - 559

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

SN - 0035-8711

IS - 1

ER -