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

Dohyeong Kim, Myungshin Im, Gabriela Canalizo, Minjin Kim, Ji Hoon Kim, Jong Hak Woo, Yoon Chan Taak, Jae Woo Kim, Mariana Lazarova

Research output: Contribution to journalArticle

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(λEdd) ≃ -0.654 ± 0.176) are only mildly higher than those of unobscured type 1 AGNs ((log(λEdd) ≃ -0.961 ± 0.008). Moreover, we find that the M BH 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.

Original languageEnglish (US)
Article number37
JournalAstrophysical Journal, Supplement Series
Volume238
Issue number2
DOIs
StatePublished - Oct 1 2018

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active galactic nuclei
atlas
near infrared
color
luminosity
H lines
extinction
dust
slopes
continuums

Keywords

  • galaxies: Seyfert
  • galaxies: active
  • galaxies: evolution
  • quasars: emission lines
  • quasars: general
  • quasars: supermassive black holes

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Medium-resolution Optical and Near-infrared Spectral Atlas of 16 2MASS-selected NIR-red Active Galactic Nuclei at z ∼ 0.3. / Kim, Dohyeong; Im, Myungshin; Canalizo, Gabriela; Kim, Minjin; Kim, Ji Hoon; Woo, Jong Hak; Taak, Yoon Chan; Kim, Jae Woo; Lazarova, Mariana.

In: Astrophysical Journal, Supplement Series, Vol. 238, No. 2, 37, 01.10.2018.

Research output: Contribution to journalArticle

Kim, Dohyeong ; Im, Myungshin ; Canalizo, Gabriela ; Kim, Minjin ; Kim, Ji Hoon ; Woo, Jong Hak ; Taak, Yoon Chan ; Kim, Jae Woo ; Lazarova, Mariana. / Medium-resolution Optical and Near-infrared Spectral Atlas of 16 2MASS-selected NIR-red Active Galactic Nuclei at z ∼ 0.3. In: Astrophysical Journal, Supplement Series. 2018 ; Vol. 238, No. 2.
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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(λEdd) ≃ -0.654 ± 0.176) are only mildly higher than those of unobscured type 1 AGNs ((log(λEdd) ≃ -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.",
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T1 - Medium-resolution Optical and Near-infrared Spectral Atlas of 16 2MASS-selected NIR-red Active Galactic Nuclei at z ∼ 0.3

AU - Kim, Dohyeong

AU - Im, Myungshin

AU - Canalizo, Gabriela

AU - Kim, Minjin

AU - Kim, Ji Hoon

AU - Woo, Jong Hak

AU - Taak, Yoon Chan

AU - Kim, Jae Woo

AU - Lazarova, Mariana

PY - 2018/10/1

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N2 - 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(λEdd) ≃ -0.654 ± 0.176) are only mildly higher than those of unobscured type 1 AGNs ((log(λEdd) ≃ -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.

AB - 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(λEdd) ≃ -0.654 ± 0.176) are only mildly higher than those of unobscured type 1 AGNs ((log(λEdd) ≃ -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.

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KW - galaxies: active

KW - galaxies: evolution

KW - quasars: emission lines

KW - quasars: general

KW - quasars: supermassive black holes

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