The AstroSat UV Deep Field North: The IRX–β Relation for the UV-selected Galaxies at z ∼ 0.5−0.7

Abstract

Abstract The relation between the observed UV continuum slope (β) and the infrared excess (IRX) is used as a powerful probe to understand the nature of dust attenuation law in high-redshift galaxies. We present a study of 83 UV-selected galaxies between a redshift of 0.5 and 0.7 from the AstroSat UV Deep Field north that encloses the GOODS-North field. Using empirical relation, we estimate the observed IRX of 52 galaxies that are detected in either one or both of the Herschel PACS 100 and 160 μm bands. We further utilize the multiband photometric data in 14–18 filters from the Ultra-Violet Imaging Telescope, KPNO, Hubble Space Telescope, Spitzer, and Herschel telescopes to perform spectral energy distribution (SED) modeling. Both the observed and model-derived IRX–β values show a large scatter within the span of previously known relations, signifying diversity in dust attenuation. We found a distinct relation between the best-fit power-law slope of the modified Calzetti relation (δ) in the IRX–β plane, where the steeper SMC-like attenuation law prefers lower δ values. Our SED model-based IRX–β relation shows a preference for steeper SMC-like attenuation, which we further confirm from the agreement between extinction-corrected star formation rates derived using the Hα emission line and the observed far-ultraviolet plus reprocessed far-IR fluxes. The current study reveals a strong positive correlation between IRX and the galaxy's stellar mass between 109.5 and 1011.0 M ⊙, signifying increased dust production in more massive star-forming galaxies.