Deep [OIII] 88um and dust continuum observations of two remarkably luminous galaxies at z~10

ALMA | Cycle 8 | 17.8hrs | PI - T. Hashimoto

We propose [OIII] 88 um and dust continuum observations of two remarkably UV-luminous (MUV=-23) galaxies at z~10. Our targets are carefully selected from the brand-new COSMOS2020 catalogue equipped with deep and unprecedentedly-wide optical to near-infrared data, the best suitable to find the rarest, brightest galaxies. Our two candidates have 1) sharp Lyman break features; 2) IRAC detection; 3) tight photo-z solutions. The volume density of these objects is consistent with the bright-end of the UV luminosity function (UVLF) studies at z=9-10 that suggests a double power-law. We aim to identify these objects by [OIII], which is proven to be the best FIR line to observe z>8 galaxies. A successful detection will confirm the power-law nature of the UVLF for the first time by spectroscopy. This has significant implication in the field of galaxy formation as they would represent a transition before significant dust attenuation and mass quenching. We will also directly observe the dust continuum,which is crucial to test the dust-poor hypothesis as the physical origins of the brightest galaxies.