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

Abstract

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 ( ) are only mildly higher than those of unobscured type 1 AGNs ( ). 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.