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We present an analysis of rest-frame UV continuum slopes, , using a sample of 1011 galaxies at 6. 5<z<13 from the EPOCHS photometric sample collated from the GTO PEARLS and public ERS/GTO/GO (JADES, CEERS, NGDEEP, GLASS) JWST NIRCam imaging across 178. 9~arcmin² of unmasked blank sky. We correct our UV slopes for the photometric error coupling bias using 200, 000 power law SEDs for each =\-1, -1. 5, -2, -2. 5, -3\ in each field, finding biases as large as -0. 55 for the lowest SNR galaxies in our sample. Additionally, we simulate the impact of rest-UV line emission (including Ly) and damped Ly systems on our measured, finding biases as large as 0. 5-0. 6 for the most extreme systems. We find a decreasing trend with redshift of =-1. 510. 08- (0. 0970. 010) z, with potential evidence for Pop. ~III stars or top-heavy initial mass functions (IMFs) in a subsample of 68 +_<-2. 8 galaxies. At z11. 5, we measure an extremely blue (Mₔₕ=-19) =-2. 730. 06, deviating from simulations, indicative of low-metallicity galaxies with non-zero Lyman continuum escape fractions f₄ₒ₂, ₋ₘ₂0 and minimal dust content. The observed steepening of d/d₁₀ (M_/M_) from 0. 220. 02 at z=7 to 0. 810. 13 at z=11. 5 implies that dust produced in core-collapse supernovae (SNe) at early times may be ejected via outflows from low mass galaxies. We also observe a flatter d/dMₔₕ=0. 030. 02 at z=7 and a shallower d/d₁₀ (M_ / M_) at z<11 than seen by HST, unveiling a new population of low mass, faint, galaxies reddened by dust produced in the stellar winds of asymptotic giant branch (AGB) stars or carbon-rich Wolf-Rayet binaries.
Austin et al. (Tue,) studied this question.