DESI Survey Reveals Large Population of Super-Eddington Accreting Black Holes in Nearby Galaxies
Astronomers have identified 18,749 Narrow-Line Seyfert 1 (NLSy1) galaxies for the first time using optical spectra from the Dark Energy Spectroscopic Instrument's first data release, producing the largest such catalog to date. NLSy1 galaxies are a peculiar class of active galactic nuclei (AGN) previously cataloged almost exclusively through Sloan Digital Sky Survey observations. The new catalog significantly expands the known NLSy1 population and reveals properties suggesting it probes a previously underrepresented, lower-luminosity segment of these objects.
A new study accepted by The Astrophysical Journal Supplement Series presents the first catalog of Narrow-Line Seyfert 1 (NLSy1) galaxies derived from the Dark Energy Spectroscopic Instrument (DESI) Data Release 1. The researchers performed detailed spectral decomposition of more than 71,000 AGN optical spectra not previously included in the Sloan Digital Sky Survey (SDSS) catalog, all at redshifts below z=0.9, identifying 18,749 new NLSy1 galaxies. Compared to the SDSS-based NLSy1 sample matched in redshift and absolute magnitude, the DESI-identified objects tend to show slightly higher bolometric luminosities and lower black hole masses, resulting in higher Eddington ratios, though with large dispersions. Notably, the fraction of DESI-NLSy1 galaxies detected in radio, X-ray, and gamma-ray catalogs is lower than for SDSS-NLSy1 sources, suggesting the DESI sample is probing a population with weaker multiwavelength emission. The catalog, which also includes a supplementary sample of broad-line Seyfert 1 galaxies, has been made publicly available on Zenodo. The authors conclude that deeper multiwavelength follow-up studies will be essential to understand the low-luminosity end of the NLSy1 population.
What's missing
It is unclear to what extent selection effects in DESI's targeting strategy versus intrinsic source properties account for the observed differences from the SDSS-NLSy1 population. The paper is a preprint accepted to ApJS but not yet formally published, so peer-review revisions remain possible.
What different sources said
- arXiv astro-phCenter
Narrow-Line Seyfert 1 Galaxies in the Dark Energy Spectroscopic Instrument Data Release 1
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