High-redshift Narrow-line Seyfert 1 Galaxies: A Candidate Sample

: Rakshit Suvendu, Stalin C.S., Kotilainen Jari, Shin Jaejin

Publisher: IOP PUBLISHING LTD

: 2021

: Astrophysical Journal Supplement

: ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES

: ASTROPHYS J SUPPL S

: ARTN 28

: 253

: 1

: 10

: 0067-0049

: 1538-4357

DOI: https://doi.org/10.3847/1538-4365/abd9bb(external)

: https://iopscience.iop.org/article/10.3847/1538-4365/abd9bb(external)

: https://research.utu.fi/converis/portal/detail/Publication/53690768(external)

The study of narrow-line Seyfert 1 galaxies (NLS1s) is now mostly limited to low redshift (z < 0.8) because their definition requires the presence of the Hβ emission line, which is redshifted out of the spectral coverage of major ground-based spectroscopic surveys at z > 0.8. We studied the correlation between the properties of Hβ and Mg ii lines of a large sample of SDSS DR14 quasars to find high-z NLS1 candidates. Based on the strong correlation of FWHM(Mg II) = (0.880 ± 0.005) × FWHM(Hβ) + (0.438 ± 0.018), we present a sample of high-z NLS1 candidates having FWHM of Mg ii < 2000 km s⁻¹. The high-z sample contains 2684 NLS1s with redshift z = 0.8–2.5 with a median logarithmic bolometric luminosity of 46.16 ± 0.42 erg s⁻¹, logarithmic black hole mass of 8.01 ± 0.35 M_⊙, and logarithmic Eddington ratio of 0.02 ± 0.27. The fraction of radio-detected high-z NLS1s is similar to that of the low-z
NLS1s and SDSS DR14 quasars at a similar redshift range, and their
radio luminosity is found to be strongly correlated with their black
hole mass.

2106.01772.pdf