Dust and its Effects on Measures of Galaxy Properties

Dust;Extinction;Galaxies: general;Galaxies: ISM;Galaxies: structure;Techniques: photometric;Astronomy;Science;Astronomy and Astrophysics

Devour, BrianMiller, Christopher John ;

University of Michigan

关键词: Dust;    Extinction;    Galaxies: general;    Galaxies: ISM;    Galaxies: structure;    Techniques: photometric;    Astronomy;    Science;    Astronomy and Astrophysics;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/138712/bdevour_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Dust in galaxies affects our measurements of galactic properties and gives insight into a range of physical processes. Robust measurements of the effects of dust attenuation on galaxy luminosities, structures, and other properties would be valuable, particularly as a function of intrinsic galaxy properties, but remain largely out of reach due to a lack of reliable dust- and inclination-independent measures of galaxy properties with which to select samples. We use dust-penetrated infrared measurements to construct new dust- and inclination-independent measurements of galaxy properties, including a new inclination-independent metric of galaxy structure. We quantify the inclination dependence of galaxy luminosities and face-on colors as a function of inclination-independent measurements of galaxy stellar mass, specific star formation rate (sSFR), size, and concentration.Relative attenuation -- defined as the difference between edge-on and face-on luminosity -- increases strongly with sSFR, is strongest for intermediate mass galaxies, and varies in complex and non-monotonic ways with galaxy structure. Face-on galaxy color reddens with decreasing sSFR and with increasing mass, and reddens quite strongly with decreasing galaxy size. Simple scaling relation-based models in which dust optical depth scales only with gas density and metallicity, coupled with published radiative transfer simulations, reproduce the observed patterns in relative attenuation and face-on color with startling accuracy. The insights offered by these models allow us to explain these complex patterns in terms of relatively simple physical properties. We also quantify how dust and inclination affect a range of traditional optical galaxy property measurements such as size, concentration, SFR, and metallicity, finding that almost all of them suffer from significant biases with dust and inclination. We conclude that dust- and inclination-independent metrics are critical for understanding dust properties and attenuation, that optical measurements of galaxy structures and other properties are strongly biased by dust and inclination, that while dust attenuation is complex it primarily varies with sSFR and size, and that simple scaling relation models can reproduce observations well and give important insight into the drivers of the seemingly complex variation of attenuation with galaxy parameters.