The Dust Attenuation Curve versus Stellar Mass for Emission Line Galaxies at z ~ 2

TL;DR

This study investigates how dust attenuation varies with stellar mass in high-redshift emission line galaxies, revealing a mass-dependent UV attenuation slope without evidence of the 2175 A bump, aligning with local starburst laws.

Contribution

It provides the first detailed analysis of the wavelength dependence of dust attenuation as a function of stellar mass at z ~ 2, extending local attenuation laws to high-redshift galaxies.

Findings

UV attenuation slope becomes shallower at lower stellar masses.

No evidence of the 2175 A extinction bump in the sample.

Attenuation law varies with stellar mass, affecting dust correction methods.

Abstract

We derive the mean wavelength dependence of stellar attenuation in a sample of 239 high redshift (1.90 < z < 2.35) galaxies selected via Hubble Space Telescope (HST) WFC3 IR grism observations of their rest-frame optical emission lines. Our analysis indicates that the average reddening law follows a form similar to that derived by Calzetti et al. for local starburst galaxies. However, over the mass range 7.2 < log M/Msolar < 10.2, the slope of the attenuation law in the UV is shallower than that seen locally, and the UV slope steepens as the mass increases. These trends are in qualitative agreement with Kriek & Conroy, who found that the wavelength dependence of attenuation varies with galaxy spectral type. However, we find no evidence of an extinction "bump" at 2175 A in any of the three stellar mass bins, or in the sample as a whole. We quantify the relation between the attenuation curve and stellar mass and discuss its implications.