Double-peaked low-ionization emission lines in active galactic nuclei

Iskra V. Strateva, Michael A. Strauss, Lei Hao, David J. Schlegel, Pat B. Hall, James E. Gunn, Li Xin Li, Željko Ivezić, Gordon T. Richards, Nadia L. Zakamska, Wolfgang Voges, Scott F. Anderson, Robert H. Lupton, Donald P. Schneider, Jon Brinkmann, Robert C. Nichol

Research output: Contribution to journalArticle

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Abstract

We present a new sample of 116 double-peaked Balmer line active galactic nuclei (AGNs) selected from the Sloan Digital Sky Survey. Double-peaked emission lines are believed to originate in the accretion disks of AGNs, a few hundred gravitational radii (R G) from the supermassive black hole. We investigate the properties of the candidate disk emitters with respect to the full sample of AGNs over the same redshifts, focusing on optical, radio, and X-ray flux, broad-line shapes and narrow-line equivalent widths, and line flux ratios. We find that the disk emitters have medium luminosities (∼10 44 ergs s -1) and FWHM on average 6 times broader than the AGNs in the parent sample. The double-peaked AGNs are 1.6 times more likely to be radio sources and are predominantly (76%) radio-quiet, with about 12% of the objects classified as LINERs. Statistical comparison of the observed double-peaked line profiles with those produced by axisymmetric and nonaxisymmetric accretion disk models allows us to impose constraints on accretion disk parameters. The observed Hα line profiles are consistent with accretion disks with inclinations smaller than 50°, surface emissivity slopes of 1.0-2.5, outer radii larger than ∼2000R G, inner radii of (200-800)R G, and local turbulent broadening of 780-1800 km s -1. The comparison suggests that 60% of accretion disks require some form of asymmetry (e.g., elliptical disks, warps, spiral shocks, or hot spots).

Original languageEnglish (US)
Pages (from-to)1720-1749
Number of pages30
JournalAstronomical Journal
Volume126
Issue number4 1774
DOIs
StatePublished - Oct 1 2003

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active galactic nuclei
accretion disks
ionization
accretion
radio
radii
emitters
H lines
profiles
emissivity
erg
inclination
line shape
hot spot
asymmetry
shock
luminosity
slopes
x rays
comparison

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Strateva, I. V., Strauss, M. A., Hao, L., Schlegel, D. J., Hall, P. B., Gunn, J. E., ... Nichol, R. C. (2003). Double-peaked low-ionization emission lines in active galactic nuclei. Astronomical Journal, 126(4 1774), 1720-1749. https://doi.org/10.1086/378367
Strateva, Iskra V. ; Strauss, Michael A. ; Hao, Lei ; Schlegel, David J. ; Hall, Pat B. ; Gunn, James E. ; Li, Li Xin ; Ivezić, Željko ; Richards, Gordon T. ; Zakamska, Nadia L. ; Voges, Wolfgang ; Anderson, Scott F. ; Lupton, Robert H. ; Schneider, Donald P. ; Brinkmann, Jon ; Nichol, Robert C. / Double-peaked low-ionization emission lines in active galactic nuclei. In: Astronomical Journal. 2003 ; Vol. 126, No. 4 1774. pp. 1720-1749.
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abstract = "We present a new sample of 116 double-peaked Balmer line active galactic nuclei (AGNs) selected from the Sloan Digital Sky Survey. Double-peaked emission lines are believed to originate in the accretion disks of AGNs, a few hundred gravitational radii (R G) from the supermassive black hole. We investigate the properties of the candidate disk emitters with respect to the full sample of AGNs over the same redshifts, focusing on optical, radio, and X-ray flux, broad-line shapes and narrow-line equivalent widths, and line flux ratios. We find that the disk emitters have medium luminosities (∼10 44 ergs s -1) and FWHM on average 6 times broader than the AGNs in the parent sample. The double-peaked AGNs are 1.6 times more likely to be radio sources and are predominantly (76{\%}) radio-quiet, with about 12{\%} of the objects classified as LINERs. Statistical comparison of the observed double-peaked line profiles with those produced by axisymmetric and nonaxisymmetric accretion disk models allows us to impose constraints on accretion disk parameters. The observed Hα line profiles are consistent with accretion disks with inclinations smaller than 50°, surface emissivity slopes of 1.0-2.5, outer radii larger than ∼2000R G, inner radii of (200-800)R G, and local turbulent broadening of 780-1800 km s -1. The comparison suggests that 60{\%} of accretion disks require some form of asymmetry (e.g., elliptical disks, warps, spiral shocks, or hot spots).",
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Strateva, IV, Strauss, MA, Hao, L, Schlegel, DJ, Hall, PB, Gunn, JE, Li, LX, Ivezić, Ž, Richards, GT, Zakamska, NL, Voges, W, Anderson, SF, Lupton, RH, Schneider, DP, Brinkmann, J & Nichol, RC 2003, 'Double-peaked low-ionization emission lines in active galactic nuclei', Astronomical Journal, vol. 126, no. 4 1774, pp. 1720-1749. https://doi.org/10.1086/378367

Double-peaked low-ionization emission lines in active galactic nuclei. / Strateva, Iskra V.; Strauss, Michael A.; Hao, Lei; Schlegel, David J.; Hall, Pat B.; Gunn, James E.; Li, Li Xin; Ivezić, Željko; Richards, Gordon T.; Zakamska, Nadia L.; Voges, Wolfgang; Anderson, Scott F.; Lupton, Robert H.; Schneider, Donald P.; Brinkmann, Jon; Nichol, Robert C.

In: Astronomical Journal, Vol. 126, No. 4 1774, 01.10.2003, p. 1720-1749.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Double-peaked low-ionization emission lines in active galactic nuclei

AU - Strateva, Iskra V.

AU - Strauss, Michael A.

AU - Hao, Lei

AU - Schlegel, David J.

AU - Hall, Pat B.

AU - Gunn, James E.

AU - Li, Li Xin

AU - Ivezić, Željko

AU - Richards, Gordon T.

AU - Zakamska, Nadia L.

AU - Voges, Wolfgang

AU - Anderson, Scott F.

AU - Lupton, Robert H.

AU - Schneider, Donald P.

AU - Brinkmann, Jon

AU - Nichol, Robert C.

PY - 2003/10/1

Y1 - 2003/10/1

N2 - We present a new sample of 116 double-peaked Balmer line active galactic nuclei (AGNs) selected from the Sloan Digital Sky Survey. Double-peaked emission lines are believed to originate in the accretion disks of AGNs, a few hundred gravitational radii (R G) from the supermassive black hole. We investigate the properties of the candidate disk emitters with respect to the full sample of AGNs over the same redshifts, focusing on optical, radio, and X-ray flux, broad-line shapes and narrow-line equivalent widths, and line flux ratios. We find that the disk emitters have medium luminosities (∼10 44 ergs s -1) and FWHM on average 6 times broader than the AGNs in the parent sample. The double-peaked AGNs are 1.6 times more likely to be radio sources and are predominantly (76%) radio-quiet, with about 12% of the objects classified as LINERs. Statistical comparison of the observed double-peaked line profiles with those produced by axisymmetric and nonaxisymmetric accretion disk models allows us to impose constraints on accretion disk parameters. The observed Hα line profiles are consistent with accretion disks with inclinations smaller than 50°, surface emissivity slopes of 1.0-2.5, outer radii larger than ∼2000R G, inner radii of (200-800)R G, and local turbulent broadening of 780-1800 km s -1. The comparison suggests that 60% of accretion disks require some form of asymmetry (e.g., elliptical disks, warps, spiral shocks, or hot spots).

AB - We present a new sample of 116 double-peaked Balmer line active galactic nuclei (AGNs) selected from the Sloan Digital Sky Survey. Double-peaked emission lines are believed to originate in the accretion disks of AGNs, a few hundred gravitational radii (R G) from the supermassive black hole. We investigate the properties of the candidate disk emitters with respect to the full sample of AGNs over the same redshifts, focusing on optical, radio, and X-ray flux, broad-line shapes and narrow-line equivalent widths, and line flux ratios. We find that the disk emitters have medium luminosities (∼10 44 ergs s -1) and FWHM on average 6 times broader than the AGNs in the parent sample. The double-peaked AGNs are 1.6 times more likely to be radio sources and are predominantly (76%) radio-quiet, with about 12% of the objects classified as LINERs. Statistical comparison of the observed double-peaked line profiles with those produced by axisymmetric and nonaxisymmetric accretion disk models allows us to impose constraints on accretion disk parameters. The observed Hα line profiles are consistent with accretion disks with inclinations smaller than 50°, surface emissivity slopes of 1.0-2.5, outer radii larger than ∼2000R G, inner radii of (200-800)R G, and local turbulent broadening of 780-1800 km s -1. The comparison suggests that 60% of accretion disks require some form of asymmetry (e.g., elliptical disks, warps, spiral shocks, or hot spots).

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Strateva IV, Strauss MA, Hao L, Schlegel DJ, Hall PB, Gunn JE et al. Double-peaked low-ionization emission lines in active galactic nuclei. Astronomical Journal. 2003 Oct 1;126(4 1774):1720-1749. https://doi.org/10.1086/378367