"Big Three Dragons": a z = 7.15 Lyman BreakGalaxy Detected in [OIII] 88 $\mu$m, [CII] 158 $\mu$m, and Dust Continuum with ALMA

Understand

We present new ALMA observations and physical properties of a Lyman Break Galaxy at z=7.15.

• Our target, B14-65666, has a bright ultra-violet (UV) absolute magnitude, $M_{\rm UV}\approx-22.4$, and has been spectroscopically identified in Ly$\alpha$ with a small rest-frame equivalent width of $\approx4$ \AA.
• Previous HST image has shown that the target is comprised of two spatially separated clumps in the rest-frame UV.
• With ALMA, we have newly detected spatially resolved [OIII] 88 $\mu$m, [CII] 158 $\mu$m, and their underlying dust continuum emission.