J/ApJS/201/23 Spectroscopy of 88 z<0.7 SDSS QSOs (Eracleous+, 2012)
A large systematic search for close supermassive binary and rapidly recoiling
black holes.
Eracleous M., Boroson T.A., Halpern J.P., Liu J.
<Astrophys. J. Suppl. Ser., 201, 23 (2012)>
=2012ApJS..201...23E 2012ApJS..201...23E
ADC_Keywords: Line Profiles ; QSOs ; Spectroscopy ; Active gal. nuclei
Keywords: galaxies: active - line: profiles - quasars: emission lines -
quasars: general
Abstract:
We have carried out a systematic search for subparsec supermassive
black hole (BH) binaries among z≲0.7 Sloan Digital Sky Survey
quasars. These are predicted by models of supermassive BH and host
galaxy coevolution, therefore their census and population properties
constitute an important test of these models. In our working
hypothesis, one of the two BHs accretes at a much higher rate than the
other and carries with it the only broad emission line region of the
system, making the system analogous to a single-lined spectroscopic
binary star. Accordingly, we used spectroscopic principal component
analysis to search for broad Hβ emission lines that are displaced
from the quasar rest frame by |Δν|≳1000km/s. This method
also yields candidates for rapidly recoiling BHs. Of the 88
candidates, several were previously reported in the literature. We
found a correlation between the peak offset and skewness of the broad
Hβ profiles, suggesting a common physical explanation for these
profiles. We carried out follow-up spectroscopic observations of 68
objects to search for changes in the peak velocities of the Hβ
lines.
Description:
We carried out follow-up observations of 68 objects from our sample
using four different telescopes: the brightest objects were observed
with the 2.4m Hiltner telescope at MDM observatory, objects of
intermediate brightness were observed with the 4m Mayall telescope at
Kitt Peak National Observatory and the 5m Hale telescope at Palomar
Observatory, while the faintest objects were observed with the 9.2m
Hobby-Eberly Telescope (HET). With the follow-up observations we
specifically targeted the Hβ lines of the quasars in our sample,
although we also did attempt to obtain spectra of the Hα and
MgII lines whenever possible. The log of observations is included in
Table 1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 77 193 Log of spectroscopic observations
table3.dat 123 89 Properties of narrow emission lines
table4.dat 54 88 Properties of broad Hβ profiles
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See also:
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)
J/AJ/140/390 : Karhunen-Loeve transform of SDSS QSOs (Boroson+, 2010)
J/ApJ/699/800 : Mass functions of active black holes (Vestergaard+, 2009)
J/ApJ/692/758 : BAL QSOs in SDSS-DR5 (Gibson+, 2009)
J/ApJ/683/L115 : Intermediate-line region in quasars (Hu+, 2008)
J/ApJ/674/668 : SDSS J102839.11+450009.4 FeII emission lines (Wang+, 2008)
J/AJ/126/1720 : ugriz and Hα of double-peaked AGN (Strateva+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- SDSS SDSS name (HHMMSS.ss+DDMMSS.s; J2000)
20- 25 F6.4 --- z [0.0767/0.7128] Redshift (1)
27- 31 F5.2 mag Vmag [15.81/19.83] Apparent V band magnitude (2)
33- 37 F5.3 mag AV Galactic visual extinction (3)
39- 44 F6.2 mag VMag Absolute V band magnitude (2)
46- 55 A10 "YYYY/MM/DD" Date UT date of the observation
57- 58 A2 --- Instr Instrument code (4)
60- 64 I5 s Exp Exposure time
66- 67 I2 --- S/N [4/88] Signal-to-noise ratio (5)
69- 72 I4 0.1nm lam1 Lower rest-frame wavelength
74- 77 I4 0.1nm lam2 Upper rest-frame wavelength
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Note (1): As measured in this paper from the peak wavelength of
[OIII] (5007) line.
Note (2): Determined from the SDSS PSF magnitudes, as described in
Section 4 of the text.
Note (3): Taken from Schlegel, Finkbeiner, & Davis (1998ApJ...500..525S 1998ApJ...500..525S).
Note (4): Instrument code as follows:
H2 = Hobby-Eberly Telescope, Low-Resolution Spectrograph - G2 grism;
resolution: 5.6Å
K = KPNO, Mayall 4m, Ritchie-Cretien spectrograph; resolution: 3.1Å
M = MDM, Hiltner 2.4m, Boller & Chivens CCD spectrograph; resolution 7.6Å
Pb = Palomar, Hale 5m, Double Spectrograph - Blue arm; resolution: 4.0Å
Pr = Palomar, Hale 5m, Double Spectrograph - Red arm; resolution: 3.1Å
S = SDSS 2.5m, SDSS spectrograph; resolution 2.7Å
See table 2 for further details.
Note (5): In the continuum near the line of interest. When the spectrum
includes the Hβ line we give the S/N in the continuum near this
line, at 4600 Angstroms. If the spectrum includes only the
MgII (2800) line, we give the S/N in the continuum near this line,
at 2900 Angstroms.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name Object name (JHHMMSS, shortened SDSS name)
9 A1 --- f_Name [f] two sets of narrow lines (1)
11 A1 --- l_Ne5 Limit flag on Ne5
13- 17 F5.3 --- Ne5 ? Observed [NeV]/[OIII] flux ratio (2)
18 A1 --- u_Ne5 Uncertainty flag on Ne5 (3)
20 A1 --- l_O2 Limit flag on O2
22- 26 F5.3 --- O2 ? Observed [OII]/[OIII] flux ratio (2)
27 A1 --- u_O2 Uncertainty flag on O2 (3)
29 A1 --- l_Ne3 Limit flag on Ne3
31- 35 F5.3 --- Ne3 ? Observed [NeIII]/[OIII] flux ratio (2)
36 A1 --- u_Ne3 Uncertainty flag on Ne3 (3)
38 A1 --- l_Hb Limit flag on Hb
40- 44 F5.3 --- Hb Observed Hβ/[OIII] flux ratio (2)
46- 53 E8.2 mW/m2 O3 Observed [OIII] flux; erg/s/cm2 (2)
55 A1 --- l_Ne5.c Limit flag on Ne5.c
57- 61 F5.3 --- Ne5.c ? Corrected [NeV]/[OIII] flux ratio (4)
62 A1 --- u_Ne5.c Uncertainty flag on Ne5.c (3)
64 A1 --- l_O2.c Limit flag on O2.c
66- 70 F5.3 --- O2.c ? Corrected [OII]/[OIII] flux ratio (4)
71 A1 --- u_O2.c Uncertainty flag on O2.c (3)
73 A1 --- l_Ne3.c Limit flag on Ne3.c
75- 79 F5.3 --- Ne3.c ? Corrected [NeIII]/[OIII] flux ratio (4)
80 A1 --- u_Ne3.c Uncertainty flag on Ne3.c (3)
82 A1 --- l_Hb.c Limit flag on Hb.c
84- 88 F5.3 --- Hb.c Corrected Hβ/[OIII] flux ratio (4)
90- 97 E8.2 mW/m2 O3.c Corrected [OIII] flux; erg/s/cm2 (4)
99-105 E7.2 10-7W LumO3 The [OIII] luminosity; erg/s (5)
107-110 I4 km/s WNe5 ? Full-Width at Half-Maximum of [NeV] (6)
112-115 I4 km/s WNe3 ? Full-Width at Half-Maximum of [OII] (6)
117-119 I3 km/s WHb ? Full-Width at Half-Maximum of Hβ (6)
121-123 I3 km/s WO3 Full-Width at Half-Maximum of [OIII] (6)
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Note (1):
f = The spectrum of J092712 includes two sets of narrow lines therefore we
report the properties of each set in separate rows. The first row gives
the properties of the set that is blueshifted and appears to be at the
same redshift as the broad lines. The second row gives the properties
of the set that is reshifted and has no broad lines associated with it.
Note (2): Integrated line fluxes are expressed relative to the integrated
flux of the [OIII] (5007) line, as measured from the observed
spectrum, without any corrections. The uncertainty is 5% or less,
unless otherwise noted.
Note (3): a colon (:) indicates an uncertainty of 10-15%
Note (4): Integrated line fluxes are expressed relative to the integrated
flux of the [OIII] (5007) line after correcting for Galactic
extinction, as described in Section 4.2 of the text. The uncertainty
is 5% or less, unless otherwise noted.
Note (5): After correcting for Galactic extinction (see Section 4.2).
Note (6): Corrected for the finite resolution of the spectrograph as
described in Section 4.2 of the text. The value is omitted when the
line is not detected.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name Object name (JHHMMSS, shortened SDSS name)
9- 13 I5 km/s FWHM ? Full-Width at Half-Maximum of Hβ line
15- 19 I5 km/s FWQM ? Full-Width at Quarter-Maximum of Hβ line
21- 25 I5 km/s dVp ? Hβ peak velocity shift
27- 29 I3 km/s e_dVp ? Uncertainty in dVp
31- 35 I5 km/s dVc ? Hβ centroid velocity shift
37- 40 I4 km/s sigma ? Velocity dispersion
42- 47 F6.3 --- Skew ? Skewness coefficient
49- 54 F6.3 --- PSkew ? Pearson skewness coefficient
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 09-Oct-2012