Medium-resolution Optical and Near-infrared Spectral Atlas of 16 2MASS-selected NIR-red Active Galactic Nuclei at z ~ 0.3

Authors

Dohyeong Kim, Seoul National UniversityFollow
Myungshin Im, Seoul National UniversityFollow
Gabriela Canalizo, University of California, Riverside
Minjin Kim, Korea Astronomy and Space Science Institute
Ji Hoon Kim, National Astronomical Observatory of Japan
Jong-Hak Woo, Seoul National University
Yoon Chan Taak, Seoul National University
Jae-Woo Kim, Korea Astronomy and Space Science Institute
Mariana Lazarova, University of Northern Colorado

ORCID IDs

Dohyeong Kim

Myungshin Im

Minjin Kim

Ji Hoon Kim

Jong-Hak Woo

Jae-Woo Kim

Date of this Version

2018

Citation

The Astrophysical Journal Supplement Series, 238:37 (25pp)

Comments

© 2018. The American Astronomical Society.

https://doi.org/10.3847/1538-4365/aadfd5

Abstract

We present medium-resolution spectra (R ~ 2000–4000) at 0.4–1.0 μm and 0.7–2.5 μm of 16 active galactic nuclei (AGNs) selected with red color in the near-infrared (NIR) of J − K > 2.0 mag at z ~ 0.3. We fit the Hβ, Hα, Pβ, and Pα lines from these spectra to obtain their luminosities and line widths. We derive the E(B − V) color excess values of the NIR-red AGNs using two methods, one based on the line-luminosity ratios and another based on the continuum slopes. The two E(B − V) values agree with each other at rms dispersion ∼0.249. About half of the NIR-red AGNs have g′ − K < 5 magnitude, and we find that these NIR-red, but blue in optical-NIR AGNs, have E(B − V) ~ 0, suggesting that a significant fraction of the NIR color-selected red AGNs are unobscured or only mildly obscured. After correcting for the dust extinction, we estimate the black hole (BH) masses and the bolometric luminosities of the NIR-red AGNs using the Paschen lines to calculate their Eddington ratios (λ_Edd). The median Eddington ratios of nine NIR-red AGNs (log(λ_Edd) ≃ -0.654 ± 0.176) are only mildly higher than those of unobscured type 1 AGNs (log(λ_Edd) ≃ -0.961 ± 0.008). Moreover, we find that the M_BH–σ* relation for three NIR-red AGNs is consistent with that of unobscured type 1 AGNs at similar redshift. These results suggest that the NIR-red color selection alone is not effective at picking up dusty, intermediate-stage AGNs.