J/ApJ/753/42 Double-peaked AGN. I. Dual AGN candidates (Comerford+, 2012)
Kiloparsec-scale spatial offsets in double-peaked narrow-line active galactic
nuclei.
I. Markers for selection of compelling dual active galactic nucleus candidates.
Comerford J.M., Gerke B.F., Stern D., Cooper M.C., Weiner B.J.,
Newman J.A., Madsen K., Barrows R.S.
<Astrophys. J., 753, 42 (2012)>
=2012ApJ...753...42C 2012ApJ...753...42C
ADC_Keywords: Active gal. nuclei ; Spectroscopy ; Redshifts
Keywords: galaxies: active; galaxies: interactions; galaxies: nuclei
Abstract:
Merger-remnant galaxies with kiloparsec (kpc) scale separation dual
active galactic nuclei (AGNs) should be widespread as a consequence of
galaxy mergers and triggered gas accretion onto supermassive black
holes, yet very few dual AGNs have been observed. Galaxies with
double-peaked narrow AGN emission lines in the Sloan Digital Sky
Survey (SDSS) are plausible dual AGN candidates, but their
double-peaked profiles could also be the result of gas kinematics or
AGN-driven outflows and jets on small or large scales. To help
distinguish between these scenarios, we have obtained spatial profiles
of the AGN emission via follow-up long-slit spectroscopy of 81
double-peaked narrow-line AGNs in SDSS at 0.03≤z≤0.36 using Lick,
Palomar, and MMT Observatories. We find that all 81 systems exhibit
double AGN emission components with ∼kpc projected spatial separations
on the sky (0.2h-170kpc<Δx<5.5h-170kpc; median
Δx=1.1h-170kpc), which suggests that they are produced by
kiloparsec-scale dual AGNs or kiloparsec-scale outflows, jets, or
rotating gaseous disks.
Description:
We selected targets from the three catalogs that have identified
active galaxies in SDSS with double-peaked [OIII] λ5007
emission lines: Wang et al. (2009, Cat. J/ApJ/705/L76), Liu et al.
(2010, Cat. J/ApJ/708/427), and Smith et al. (2010,
Cat. J/ApJ/716/866) (we note that one of the objects in Smith et al.
2010 was originally identified in Xu & Komossa 2009ApJ...705L..20X 2009ApJ...705L..20X).
We obtained follow-up long-slit spectroscopy, during 2009 and 2010,
for a sample of 81 double-peaked AGNs at 0.03≤z≤0.36 and
14.5≤r≤18.5 using the Kast Spectrograph at the Lick 3m telescope
(pixel size 0.78"), the Double Spectrograph (DBSP) on the Palomar 5m
telescope (pixel size 0.47" for the red detector and 0.39" for the
blue detector), and the Blue Channel Spectrograph on the MMT 6.5m
telescope (pixel size 0.29"). We observed each target twice, with the
slit at two different position angles, in order to determine the
orientation of the AGN emission components on the plane of the sky.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 86 81 Summary of observations
table2.dat 95 81 Summary of measurements
--------------------------------------------------------------------------------
See also:
VII/269 : SDSS Quasar Catalog, DR9Q (Paris+, 2012)
J/ApJS/201/31 : Emission-line galaxies from SDSS. I. (Ge+, 2012)
J/ApJS/201/23 : Spectroscopy of 88 z<0.7 SDSS QSOs (Eracleous+, 2012)
J/ApJ/716/866 : SDSS search for binary AGN (Smith+, 2010)
J/ApJ/708/427 : Type 2 AGNs with double-peaked [OIII] lines (Liu+, 2010)
J/ApJ/705/L76 : AGNs with double-peaked [OIII] lines (Wang+, 2009)
J/AJ/126/1720 : ugriz and Hα of double-peaked AGN (Strateva+, 2003)
http://www.sdss.org/ : SDSS home page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS SDSS designation (JHHMMSS.ss+DDMMSS.s)
26- 41 A16 --- T/I Telescope/instrument (Lick/Kast, MMT/Blue Channel
or Palomar/DBSP)
43- 53 A11 "Y/M/D" Date1 First observation date; UT (1)
54 A1 --- --- [,]
55- 65 A11 "Y/M/D" Date2 Second observation date if differs from Date1 (1)
67- 70 F4.1 deg PA1 [0/180] Position angle of slit in first
observation (degrees east of north)
72- 76 F5.1 deg PA2 [0/180] Position angle of slit in second
observation (degrees east of north)
78- 81 I4 s Exp1 Exposure time at first position angle (2)
82 A1 --- --- [,]
83- 86 I4 s Exp2 ? Exposure time at second position angle (2)
--------------------------------------------------------------------------------
Note (1): Where two dates are listed, the first position angle was observed
on the first date and the second position angle was observed on the
second date.
Note (2): Where two exposure times are listed, the first exposure time was
for the first position angle and the second exposure time was for the
second position angle.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- SName SDSS short name (HHMM+DDMM)
10- 12 A3 --- n_SName [p,s ] Interesting features of the candidate (4)
14- 18 F5.3 --- z [0.03/0.4] Redshift
20 I1 --- T [1/2] Spectral type of the AGN (type I or II)
22- 24 I3 km/s dV [222/686] Velocity offset ΔV between the
[OIII]5007 peaks in the SDSS spectrum.
26- 27 I2 km/s e_dV Error in dV
29- 32 F4.2 arcsec dXang Angular projected spatial offset between the two
[OIII]5007 emission features on the sky.
34- 37 F4.2 arcsec e_dXang Error in dXang
39- 42 F4.2 kpc dXkpc Physical projected spatial offset (in kpc/h70)
44- 47 F4.2 kpc e_dXkpc Error in dXkpc
49 A1 --- Em [ce] Physical extent of double AGN emission
features in 2D spectrum: compact or extended.
51- 55 F5.1 deg PA [0/180] Position angle between the two [OIII]5007
emission features on the sky (East of North)
57- 60 F4.1 deg e_PA Error in PA and dPA
62- 65 F4.1 deg dPA [0/90] Angle with major axis (5)
67- 71 F5.3 --- ell [0/1] Ellipticity
73- 84 A12 --- Oobs Other published observation(s) (6)
86- 95 A10 --- Ref Reference(s) (7)
--------------------------------------------------------------------------------
Note (4): Flag as follows:
p = promising dual AGN candidate that has double optical AGN emission
components oriented in the plane of the host galaxy, where the difference
in position angles Δθ are within 3σ deviations from
zero. (See section 7.4.1).
s = double-peaked AGN that exhibit double stellar components in AO imaging
(Section 5), that has double AGN emission components with spatial
separations and position angles comparable to the spatial separations and
position angles between the double stellar components in the corresponding
AO image (Figure 8). See section 7.4.2 for further explanations.
Note (5): Absolute value of the position angle difference between the measured position angle and the isophotal position angle
of the major axis of the object. Degrees east of north.
Note (6): Observation as follows:
NIR = near infrared imaging;
SS = slit spectroscopy;
VLBA = Very Long Baseline Array observations;
IFU = integral field unit spectroscopy;
HST = Hubble Space Telescope imaging;
VLA = Very Large Array observations;
Chandra = Chandra observations.
Note (7): Reference as follows:
1 = Liu et al. (2010, Cat. J/ApJ/708/427);
2 = Wang et al. (2009, Cat. J/ApJ/705/L76);
3 = Fu et al. (2012ApJ...745...67F 2012ApJ...745...67F);
4 = Shen et al. (2011ApJ...735...48S 2011ApJ...735...48S);
5 = Tingay & Wayth (2011AJ....141..174T 2011AJ....141..174T);
6 = Smith et al . (2010, Cat. J/ApJ/716/866);
7 = Rosario et al. (2011ApJ...739...44R 2011ApJ...739...44R);
8 = Fu et al. (2011ApJ...733..103F 2011ApJ...733..103F);
9 = McGurk et al. (2011ApJ...738L...2M 2011ApJ...738L...2M);
10 = Rosario et al. (2010ApJ...716..131R 2010ApJ...716..131R);
11 = Comerford et al. (2011ApJ...737L..19C 2011ApJ...737L..19C).
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 11-Feb-2014