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  • The MOSDEF survey: probing resolved stellar populations at z  ∼ 2 Using a new bayesian-defined morphology metric called patchiness
Title: The MOSDEF survey: probing resolved stellar populations at z  ∼ 2 Using a new bayesian-defined morphology metric called patchiness
ABSTRACT We define a new morphology metric called ‘patchiness’ (P) that is sensitive to deviations from the average of a resolved distribution, does not require the galaxy centre to be defined, and can be used on the spatially resolved distribution of any galaxy property. While the patchiness metric has a broad range of applications, we demonstrate its utility by investigating the distribution of dust in the interstellar medium (ISM) of 310 star-forming galaxies at spectroscopic redshifts 1.36 < z < 2.66 observed by the MOSFIRE Deep Evolution Field survey. The stellar continuum reddening distribution, derived from high-resolution multiwaveband CANDELS/3D-HST imaging, is quantified using the patchiness, Gini, and M20 coefficients. We find that the reddening maps of high-mass galaxies, which are dustier and more metal-rich on average, tend to exhibit patchier distributions (high P) with the reddest components concentrated within a single region (low M20). Our results support a picture where dust is uniformly distributed in low-mass galaxies (≲1010 M⊙), implying efficient mixing of dust throughout the ISM. On the other hand, the dust distribution is patchier in high-mass galaxies (≳1010 M⊙). Dust is concentrated near regions of active star formation and dust mixing time-scales are expected to be longer in high-mass galaxies, such that the outskirt regions of these physically larger galaxies remain relatively unenriched. This study presents direct evidence for patchy dust distributions on scales of a few kpc in high-redshift galaxies, which previously has only been suggested as a possible explanation for the observed differences between nebular and stellar continuum reddening, star formation rate indicators, and dust attenuation curves.  more » « less
Award ID(s):
2009313
PAR ID:
10427768
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ;
Date Published:
Journal Name:
Monthly Notices of the Royal Astronomical Society
Volume:
518
Issue:
3
ISSN:
0035-8711
Page Range / eLocation ID:
4214 to 4237
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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