We analyze nebular dust attenuation and its correlation with stellar mass (M*) and UV spectral slope (β) in 33 lensed, low-mass star-forming galaxies at 1. 4 z 2. 6, using Keck/MOSFIRE rest-frame optical spectroscopy. Located behind three massive lensing galaxy clusters Abell 1689, MACS J1149. 5+2223, and MACS J0717. 5+3745, galaxies in our sample have a median stellar mass of (M*/M_) =8. 3 and an intrinsic UV absolute magnitude range of -20. 9<Mₔₕ<-13. We measure nebular dust attenuation via Balmer optical depth (τ₁) defined as the Hα/Hβ ratio. We also derive physical properties from Hubble Space Telescope multi-wavelength photometry and construct composite spectra using median stacking in bins of M* and β. We find that the τ₁-β relation for the dwarf galaxies in this study is best represented by SMC dust curve. This is consistent with previous studies of low-metallicity galaxies at similar redshifts, which show a steep attenuation curve similar to the SMC curve, in contrast to high-metallicity and more massive galaxies that exhibit a much shallower dust attenuation curve. We also investigate the relationship between nebular dust attenuation and stellar mass, E (B-V) ₍₄₁ₔ₋₀ₑ-M*, down to (M*/M_) 7. We demonstrate that this relation does not notably evolve with redshift and is consistent with what has been observed for local SDSS galaxies at similar low stellar masses.
Alavi et al. (Wed,) studied this question.