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arXiv · 2606.10455

The Quasar Main Sequence of Super-Eddington NLSy1 Galaxies

Alberto Domínguez·Suvendu Rakshit·Vaidehi S. Paliya·D. J. Saikia·C. S. Stalin
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Abstract

The quasar main sequence, or Eigenvector 1 (EV1), describes the optical diversity of active galactic nuclei (AGN), with Narrow-Line Seyfert 1 (NLSy1) galaxies anchoring the high-accretion end. Recent discoveries of overly massive black holes in the early Universe highlight the need to study low-redshift, low-mass super-Eddington accretors as analogs of rapid black hole growth. We map a population of 18,749 NLSy1 galaxies identified in the Dark Energy Spectroscopic Instrument Data Release 1 (DESI DR1) onto the EV1 plane to determine whether they represent a distinct population of super-accretors. We compare the spectral properties of the DESI DR1 NLSy1 sample with the SDSS DR17 NLSy1 catalog. We extract key parameters, including the broad H-beta full width at half maximum (FWHM) and Fe II strength (R4570). To evaluate their accretion states, we derive single-epoch virial black hole masses using an Fe II strength-dependent scaling relation and an Eddington rate-dependent fundamental plane, both of which confirm their high accretion rates. The DESI DR1 NLSy1 population shows a consistent shift toward the extreme end of the EV1 parameter space, possessing strong Fe II emission (median R4570 = 0.97 +/- 0.36), similar to the SDSS sample (median R4570 = 0.97 +/- 0.34). Furthermore, considering both calibrations, DESI and SDSS sources harbor low-mass black holes (median log black hole mass ~6.81-6.85). About 50% of the NLSy1 galaxies exhibit super-Eddington accretion (log Eddington ratio > 0). The unprecedented sensitivity of DESI has unveiled a large population of low-mass, super-Eddington accreting sources. These intriguing EV1 objects struggle to process luminous accretion flows, naturally producing the observed intense Fe II emission. This unique sample provides a rich statistical dataset of low-redshift super-Eddington accretors for understanding early-Universe black hole growth.

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Alberto Domínguez, Suvendu Rakshit, Vaidehi S. Paliya, D. J. Saikia, C. S. Stalin. 2026-08-21. The Quasar Main Sequence of Super-Eddington NLSy1 Galaxies. https://arxiv.org/abs/2606.10455

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