J/ApJ/746/L22 Dual AGNs in the nearby Universe (Koss+, 2012)
Understanding dual active galactic nucleus activation in the nearby Universe.
Koss M., Mushotzky R., Treister E., Veilleux S., Vasudevan R., Trippe M.
<Astrophys. J., 746, L22 (2012)>
=2012ApJ...746L..22K 2012ApJ...746L..22K
ADC_Keywords: Active gal. nuclei ; X-ray sources ; Galaxies, nearby
Keywords: galaxies: active - galaxies: interactions - X-rays: galaxies
Abstract:
We study the fraction of dual active galactic nuclei (AGNs) in a
sample of 167 nearby (z < 0.05), moderate-luminosity, ultra-hard
X-ray-selected AGNs from the all-sky Swift Burst Alert Telescope (BAT)
survey. Combining new Chandra and Gemini observations together with
optical and X-ray observations, we find that the dual AGN frequency at
scales <100 kpc is ∼10% (16/167). Of the 16 dual AGNs, only 3 (19%)
were detected using X-ray spectroscopy and were not detected using
emission line diagnostics. Close dual AGNs (<30 kpc) tend to be more
common among the most X-ray luminous systems. In dual AGNs, the X-ray
luminosity of both AGNs increases strongly with decreasing galaxy
separation, suggesting that the merging event is key in powering both
AGNs. Fifty percent of the AGNs with a very close companion (<15 kpc)
are dual AGNs. We also find that dual AGNs are more likely to occur in
major mergers and tend to avoid absorption line galaxies with
elliptical morphologies. Finally, we find that SDSS Seyferts are much
less likely than BAT AGNs (0.25% versus 7.8%) to be found in dual AGNs
at scales <30 kpc because of a smaller number of companion galaxies,
fiber collision limits, a tendency for AGNs at small separations to be
detected only in X-rays, and a higher fraction of dual AGN companions
with increasing AGN luminosity.
Description:
The Burst Alert Telescope (BAT) AGN sample consists of 167 nearby
(z<0.05) ultra-hard X-ray BAT-detected AGNs from Koss et al. (2011,
Cat. J/ApJ/739/57) catalog in the Northern sky (>-25°), with low
Galactic extinction (E(B-V)<0.5). For each BAT AGN, we search the
SDSS, 6DF, 2DF, and NED for apparent companions within 100kpc with
small radial velocity differences (<300km/s). To determine the AGN
nature of the galaxy companions, we use X-ray data from Chandra, XRT,
or XMM.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 90 103 Dual AGN study of BAT sample
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2013)
B/xmm : XMM-Newton Obs. Log (XMM-Newton Science Operation Center, 2012)
II/306 : The SDSS Photometric Catalog, Release 8 (Adelman-McCarthy+, 2011)
VII/259 : 6dF galaxy survey final redshift release (Jones+, 2009)
II/268 : The 2dF QSO Redshift Survey Input Catalogue (Smith+ 2005)
VII/241 : The 2dF QSO Redshift Survey (Croom+ 2004)
VII/250 : The 2dF Galaxy Redshift Survey (2dFGRS) (2dFGRS Team, 1998-2003)
J/ApJ/728/58 : Swift-BAT survey of AGNs (Burlon+, 2011)
J/ApJ/739/57 : Ultra hard X-ray AGNs in the Swift/BAT survey (Koss+, 2011)
J/A+A/524/A64 : The 54-month Palermo BAT-survey catalogue (Cusumano+, 2010)
J/A+A/510/A48 : Palermo Swift-BAT Hard X-ray Catalogue (Cusumano+, 2010)
J/ApJ/681/113 : Swift BAT survey of AGNs (Tueller+, 2008)
J/ApJ/678/102 : BAT X-ray survey. I. (Ajello+, 2008)
J/ApJ/633/L77 : SWIFT/BAT detections of AGN (Markwardt+, 2005)
http://www.sdss.org/ : SDSS Web site
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- Sys [D/S] AGN system type (D=dual or S=single)
(dual when the companion is an AGN)
3- 25 A23 --- BAT BAT source name
27- 50 A24 --- Gal Galaxy companion
52- 55 F4.1 kpc Sep [1.5/99.1] Projected separation
57- 61 F5.1 --- M1/M2 [0.4/151.4]? Host galaxy stellar mass ratio (2)
63 A1 --- l_XLum Limit flag on XLum
64- 70 F7.5 10+35W XLum [0.0001/9.3]? Galaxy companion 2-10keV
luminosity (3)
72- 82 A11 --- Diag Galaxy companion AGN optical diagnostic (4)
84- 86 A3 --- r_XLum Source of X-ray observations (5)
88- 90 A3 --- r_Diag Reference for Diag (6)
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Note (2): Between BAT AGN and companion.
Note (3): In units of 1042erg/s. A blank value indicates no X-ray data
available for the companion.
Note (4): 3 classifications (L=LINER, C=Composite) from emission line
diagnostics of Veilleux and Osterbrock (1987ApJS...63..295V 1987ApJS...63..295V), and
revised by Kewley et al. (2006MNRAS.372..961K 2006MNRAS.372..961K):
* [O III] 5007/Hβ vs. [N II] 6583/Hα,
* [S II] 6717,6731/Hα
* [O I] 6300/Hα ratios.
Note (5): Source as follows:
CXO = Chandra;
XMM = XMM
XRT = Swift X-ray telescope.
Note (6): Reference as follow:
S = SDSS;
G = Gemini;
N = NED;
1 = Ho et al. (1997ApJS..112..391H 1997ApJS..112..391H);
2 = Winter et al. (2010ApJ...710..503W 2010ApJ...710..503W);
3 = Veilleux & Osterbrock (1987ApJS...63..295V 1987ApJS...63..295V);
4 = Trippe in preparation;
5 = Veilleux et al. (1995ApJS...98..171V 1995ApJS...98..171V);
6 = de Carvalho & Coziol (1999AJ....117.1657D 1999AJ....117.1657D).
2DF = 2dF
6DF = 6dF (Cat. VII/259)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 17-Sep-2013