The discovery of rest-frame UV colour gradients and a diversity of dust morphologies in bright <i>z</i> ≃ 7 Lyman-break galaxies

We present deep ALMA dust continuum observations for a sample of luminous ($M_{\rm UV} < -22$) star-forming galaxies at $z \simeq 7$. detect five the six sources in far-infrared (FIR), providing key constraints on obscured star-formation rate (SFR) and infrared-excess-$\beta$ (IRX-$\beta$) relation without need stacking. Despite showing blue rest-frame UV slopes ($\beta -2$) we find that 35-75 percent total SFR is obscured. IRX-$\beta$ derived these 7$ consistent with found local star-burst galaxies. Using our relatively high-resolution (FWHM $\simeq 0.7\,{\rm arcsec}$) identify diversity morphologies sample. both compact emission appears offset relative to unobscured components extended co-spatial light. In majority strong colour gradients (with up $\Delta \beta 0.7$-$1.4$) as probed by multi-band UltraVISTA ground-based data. The observed redder colours are spatially correlated location FIR detection. Our results show even bright Lyman-break peak typically hosted fainter, redder, regions UV, which have an fraction $f_{\rm obs} \ge 0.8$. As well demonstrating importance within Epoch Reionization, provide exciting taster rich resolved datasets will be obtained from JWST follow-up redshifts.