The Quasar Main Sequence of Highly Accreting NLSy1 Galaxies
Abstract
The quasar main sequence, or Eigenvector 1 (EV1), describes the optical diversity of active galactic nuclei, 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 18,749 NLSy1 galaxies from the Dark Energy Spectroscopic Instrument Data Release 1 (DESI DR1) onto the EV1 plane. We compare the spectral properties of the DESI DR1 NLSy1 sample with the SDSS DR17 NLSy1 catalog, analyzed homogeneously. 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 ratio-dependent fundamental plane, and test this choice with an Fe II-independent calibration. The DESI DR1 NLSy1 population occupies the extreme end of the EV1 parameter space, with strong Fe II emission (median R4570 = 0.96 +/- 0.35), similar to the SDSS sample (0.96 +/- 0.36). Under both calibrations, DESI and SDSS sources harbor low-mass black holes (median log black hole mass ~6.81-6.85). About 50% of both samples formally exceed the Eddington limit (log Eddington ratio > 0); this fraction drops to ~8-9% with the Fe II-independent calibration and is thus strongly calibration dependent. The unprecedented sensitivity of DESI has unveiled a large population of low-mass, highly accreting NLSy1 galaxies. Under the high-accretion interpretation, a geometrically thick inner disk would shield the outer broad-line region, naturally producing the observed strong Fe II emission. This sample provides a statistical dataset of low-redshift candidate super-Eddington accretors for understanding early-Universe black hole growth.
Related
- Unraveling the mysteries of jets in peculiar NLSy1 galaxies through multiwavelength variability
- Disk truncation triggers relativistic jet launching of a highly accreting supermassive black hole
- Disk Truncation Triggers Relativistic Jet Launching of a Highly Accreting Supermassive Black Hole
- Mapping the Quasar Main Sequence in the UV range: A Connection with the UV Fe III Emission
- Exploring the UV Fe III Emission along the Quasar Main Sequence
BibTeX
@misc{dominguez2026quasar,
title = {{The Quasar Main Sequence of Highly Accreting NLSy1 Galaxies}},
author = {Alberto Domínguez and Suvendu Rakshit and Vaidehi S. Paliya and D. J. Saikia and C. S. Stalin},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2606.10455},
eprint = {2606.10455},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.10455},
}
RIS
TY - UNPB
TI - The Quasar Main Sequence of Highly Accreting NLSy1 Galaxies
AU - Alberto Domínguez
AU - Suvendu Rakshit
AU - Vaidehi S. Paliya
AU - D. J. Saikia
AU - C. S. Stalin
PY - 2026
DA - 2026/11/02
PB - arXiv
DO - 10.48550/arxiv.2606.10455
UR - https://arxiv.org/abs/2606.10455
AB - The quasar main sequence, or Eigenvector 1 (EV1), describes the optical diversity of active galactic nuclei, 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 18,749 NLSy1 galaxies from the Dark Energy Spectroscopic Instrument Data Release 1 (DESI DR1) onto the EV1 plane. We compare the spectral properties of the DESI DR1 NLSy1 sample with the SDSS DR17 NLSy1 catalog, analyzed homogeneously. 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 ratio-dependent fundamental plane, and test this choice with an Fe II-independent calibration. The DESI DR1 NLSy1 population occupies the extreme end of the EV1 parameter space, with strong Fe II emission (median R4570 = 0.96 +/- 0.35), similar to the SDSS sample (0.96 +/- 0.36). Under both calibrations, DESI and SDSS sources harbor low-mass black holes (median log black hole mass ~6.81-6.85). About 50% of both samples formally exceed the Eddington limit (log Eddington ratio > 0); this fraction drops to ~8-9% with the Fe II-independent calibration and is thus strongly calibration dependent. The unprecedented sensitivity of DESI has unveiled a large population of low-mass, highly accreting NLSy1 galaxies. Under the high-accretion interpretation, a geometrically thick inner disk would shield the outer broad-line region, naturally producing the observed strong Fe II emission. This sample provides a statistical dataset of low-redshift candidate super-Eddington accretors for understanding early-Universe black hole growth.
ER -