Direct pathway to the Early Supermassive Black Holes: A Red Super-Eddington Quasar in a Massive Starburst Host at $z=7.2$

Kavli Affiliate: Luis Ho
| Summary:
We present a panchromatic optical-mm characterization of GNz7q, a recently identified X-ray weak, rapidly growing red quasar embedded within a dusty starburst galaxy at $z=7.1899$, using the full suite of JWST/NIRCam, NIRSpec, MIRI, and archival NOEMA observations. Our deep NIRSpec/G395M spectroscopy reveals unambiguous broad Balmer emission (FWHM $=2221pm20$kms$^-1$), confirming a super-Eddington accreting black hole ($λ_rm Edd=2.7pm0.4$) with a mass of $log(M_rm BH/M_odot)=7.55pm0.34$, using accretion-rate corrected BH mass estimators. After subtracting the point source, we robustly detect stellar emission from the host galaxy across multiple NIRCam and MIRI filters. Out joint morphological-spectral analysis yields a stellar mass of $log (M_*/M_odot)=10.5pm0.4$ and an intense star formation rate of $rm SFR=330pm97,M_odot,rm yr^-1$, confirming the host as a massive, dusty starburst galaxy. We find that GNz7q lies on the local $M_rm BH$-$M_*$ relation ($M_rm BH/M_*simeq 0.001$) and is well positioned to evolve into the locus of massive SDSS quasars with $log (M_rm BH/M_odot)approx 9$ and $M_*approx 10^11,M_odot$ at $zsim 6$, owing to its remarkably rapid growth in both the black hole and its host galaxy. This stands in stark contrast to many recently reported JWST AGN populations at similar redshifts, including the little red dots (LRDs), whose weak or undetected star formation makes it difficult for them to grow into the massive galaxies hosting SDSS-like quasars. These results suggest that GNz7q marks as a rare, pivotal phase of early BH-galaxy co-eolution, plausibly providing a crucial direct pathway to the supermassive black hole systems within the first billion years of the Universe.
| Search Query: arXiv Query: search_query=au:”Ho Luis”&id_list=&start=0&max_results=10
Read More