Chasing big bubbles: the confirmation of a bright z=9.8 galaxy

NOEMA | 30.0hrs | PI - F. Valentino

We request 30h of NOEMA/2mm time to spectroscopically confirm the redshift of a novel and robust UV- bright (MUV=-22.9 mag) galaxy candidate at z=9.82 from the new COSMOS2020 catalog. The candidate is massive (log(M/Msun)=10.5), highly star-forming (log(SFR/Msun/yr)=2.2), and shows a tight redshift PDF, which can be covered at 90% with a single NOEMA frequency setting targeting [CII]. These properties suggest a sufficient metal enrichment and encourage the search for this line and its underlying dust continuum emission. If confirmed, this will be a redshift record-breaking discovery, while the [CII] and dust IR luminosity will give us insight into the gas and obscured SFR. This will allow us to explore the SFR or MUV-L[CII] and IRX-beta relations at the unprecedented z~10 regime. This would also support the role of ultra-bright sources to generate large reionization bubbles. The target is 1.5dex more star forming than the only other source confirmed with FIR lines at z=9.11 and it does not suffer from lensing uncertainties. The large bandwidth and arcsec resolution of NOEMA are optimal to carry out this project.