J/MNRAS/463/24 Type 2 AGNs with double-peaked narrow emission lines (Lyu+, 2016)
A high fraction of double-peaked narrow emission lines in powerful
active galactic nuclei.
Lyu Y., Liu X.
<Mon. Not. R. Astron. Soc., 463, 24-36 (2016)>
=2016MNRAS.463...24L 2016MNRAS.463...24L (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Redshifts ; Equivalent widths
Keywords: black hole physics - galaxies: active - galaxies: interactions -
galaxies: nuclei = quasars: general - galaxies: Seyfert
Abstract:
1 per cent of redshift z∼0.1 active galactic nuclei (AGNs) show
velocity splitting of a few hundred km/s in the narrow emission lines
in spatially integrated spectra. Such line profiles have been found to
arise from the bulk motion of ionized gas clouds associated with
galactic-scale outflows, merging pairs of galaxies each harbouring a
supermassive black hole (SMBH), and/or galactic-scale disc rotation.
It remains unclear, however, how the frequency of narrow-line velocity
splitting may depend on AGN luminosity. Here we study the correlation
between the fraction of Type 2 AGNs with double-peaked narrow emission
lines and AGN luminosity as indicated by [OIII] λ5007
emission-line luminosity L[OIII]. We combine the sample of Liu et
al. (2010. Cat. J/ApJ/708/427) at z∼0.1 with a new sample of 178 Type
2 AGNs with double-peaked [OIII] emission lines at z∼0.5. We select
the new sample from a parent sample of 2089 Type 2 AGNs from the
SDSS-III/Baryon Oscillation Spectroscopic Survey. We find a
statistically significant (∼4.2σ) correlation between L[OIII]
and the fraction of objects that exhibit double-peaked narrow emission
lines among all Type 2 AGNs, corrected for selection bias and
incompleteness due to [OIII] line width, equivalent width, splitting
velocity, and/or equivalent width ratio between the two velocity
components. Our result suggests that galactic-scale outflows and/or
merging pairs of SMBHs are more prevalent in more powerful AGNs,
although spatially resolved follow-up observations are needed to
resolve the origin(s) for the narrow-line velocity splitting for
individual AGNs.
Description:
We have studied the luminosity dependence of the fraction of
double-peaked narrow emission lines in optically selected Type 2
(obscured) AGNs using [OIII] λ5007 luminosity as a surrogate
for AGN luminosity. We have combined the sample of (Liu et al., 2010,
Cat. J/ApJ/708/427) at z∼0.1 with a new sample of 178 AGNs at z∼0.5
with double-peaked narrow lines that we have identified from the
SDSS-III/BOSS survey. The new sample was selected from a parent sample
of 2089 Type 2 AGNs with high quality BOSS spectra
(amplitude-over-noise ratios >5 for all the relevant emission lines).
It includes more galaxies at higher redshifts with larger intrinsic
AGN luminosity which allows us to probe a large enough dynamic range
to address the luminosity dependence.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 86 178 A new sample of 178 Type 2 Seyfert AGNs with
double-peaked narrow [OIII] emission lines at
∼0.5 selected from SDSS-III/BOSS
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See also:
J/ApJ/708/427 : Type 2 AGNs with double-peaked [OIII] lines (Liu+, 2010)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- SDSS SDSS designation (JHHMMSS.ss+DDMMSS.s)
21- 24 I4 --- Plate SDSS plate number
26- 28 I3 --- Fiber SDSS fiber number
30- 34 I5 d MJD SDSS MJD number
36- 41 F6.4 --- z BOSS pipeline redshift
43- 48 F6.4 --- zg GANDALF-corrected redshift
49 A1 --- n_zg [*] Note on zg (1)
50- 53 I4 km/s FWHM[OIII]1 FWHM of [OIII] blueshifted component
55- 58 I4 km/s FWHM[OIII]2 FWHM of [OIII] redshifted component
60- 63 I4 km/s v[OIII]1 Velocity offset relative to the systemic
redshift of the host galaxy of
[OIII] blueshifted component (1)
65- 68 I4 km/s v[OIII]2 Velocity offset relative to the systemic
redshift of the host galaxy of
[OIII] redshifted component
70- 73 I4 km/s vHb1 Velocity offset relative to the systemic
redshift of the host galaxy of
Hβ blueshifted component
75- 78 I4 km/s vHb2 Velocity offset relative to the systemic
redshift of the host galaxy of
Hβ redshifted component
80- 82 I3 0.1nm EW[OIII]1 Equivalent width of [OIII] blueshifted
component
84- 86 I3 0.1nm EW[OIII]2 Equivalent width of [OIII] redshifted
component
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Note (1): velocity offsets relative to the systemic redshift of the host galaxy
either from the BOSS pipeline (z) for the majority of the sample or from the
GANDALF-corrected redshift (zg) for a few objects denoted with an '*'.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 30-Apr-2018