J/ApJ/831/7 SDSS-RM project: peak velocities of QSOs (Shen+, 2016)
The Sloan Digital Sky Survey Reverberation Mapping project: velocity shifts
of quasar emission lines.
Shen Y., Brandt W.N., Richards G.T., Denney K.D., Greene J.E., Grier C.J.,
Ho L.C., Peterson B.M., Petitjean P., Schneider D.P., Tao C., Trump J.R.
<Astrophys. J., 831, 7-7 (2016)>
=2016ApJ...831....7S 2016ApJ...831....7S (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Spectroscopy ; Line Profiles ; Redshifts ; Surveys
Keywords: black hole physics; galaxies: active; line: profiles;
quasars: general; surveys
Abstract:
Quasar emission lines are often shifted from the systemic velocity due
to various dynamical and radiative processes in the line-emitting
region. The level of these velocity shifts depends both on the line
species and on quasar properties. We study velocity shifts for the
line peaks (not the centroids) of various narrow and broad quasar
emission lines relative to systemic using a sample of 849 quasars from
the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project.
The coadded (from 32 epochs) spectra of individual quasars have
sufficient signal-to-noise ratio (S/N) to measure stellar absorption
lines to provide reliable systemic velocity estimates, as well as weak
narrow emission lines. The large dynamic range in quasar luminosity
(∼2dex) of the sample allowed us to explore potential luminosity
dependence of the velocity shifts. We derive average line peak
velocity shifts as a function of quasar luminosity for different
lines, and quantify their intrinsic scatter. We further quantify how
well the peak velocity can be measured as a function of continuum S/N,
and demonstrate that there is no systematic bias in the velocity
measurements when S/N is degraded to as low as ∼3 per SDSS pixel
(∼69kms/s). Based on the observed line shifts, we provide empirical
guidelines on redshift estimation from [OII]λ3727,
[OIII]λ5007, [NeV]λ3426, MgII, CIII], HeIIλ1640,
broad Hβ, CIV, and SiIV, which are calibrated to provide unbiased
systemic redshifts in the mean, but with increasing intrinsic
uncertainties of 46, 56, 119, 205, 233, 242, 400, 415, and 477kms/s,
in addition to the measurement uncertainties. These results
demonstrate the infeasibility of measuring quasar redshifts to better
than ∼200kms/s with only broad lines.
Description:
The SDSS-RM quasar sample includes 849 broad-line quasars at 0.1<z<4.5
with a flux limit of ipsf=21.7. The quasars were selected using a
variety of methods combining optical, infrared and variability
selection. The details of the target selection are presented in the
sample characterization paper (Shen+ 2016, in preparation).
The spectroscopic data used in this work are from the 32 epochs taken
in 2014 as part of the SDSS-RM project within the SDSS-III
(Eisenstein+ 2011AJ....142...72E 2011AJ....142...72E) Baryon Oscillation Spectroscopic
Survey (BOSS, Dawson+ 2013AJ....145...10D 2013AJ....145...10D), using the BOSS
spectrograph on the 2.5m SDSS telescope. The wavelength coverage of
BOSS spectroscopy is ∼3650-10400Å, with a spectral resolution of
R∼2000.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 267 849 Peak velocity measurements for each of the 849
quasars in the Sloan Digital Sky Survey
Reverberation Mapping (SDSS-RM) sample
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See also:
VII/270 : SDSS quasar catalog: tenth data release (Paris+, 2014)
VII/269 : SDSS Quasar Catalog, DR9Q (Paris+, 2012)
J/ApJ/818/30 : Lag measurements of 15 z<0.8 QSOs from SDSS-RM (Shen+, 2016)
J/ApJ/817/55 : NIR spectroscopy of 1.5<z<3.5 broad-band QSOs (Shen, 2016)
J/ApJ/811/91 : SDSS-RM project: z<1 QSO host galaxies (Matsuoka+, 2015)
J/ApJ/805/96 : SDSS-RM project: velocity dispersions of QSOs (Shen+, 2015)
J/ApJS/217/26 : Lick AGN monitoring 2011: light curves (Barth+, 2015)
J/ApJS/216/4 : SDSS-RM project: technical overview (Shen+, 2015)
J/MNRAS/431/836 : Type 1 AGN at low z. III. (Stern+, 2013)
J/ApJS/201/23 : Spectroscopy of 88 z<0.7 SDSS QSOs (Eracleous+, 2012)
J/ApJ/753/125 : NIR spectroscopy follow-up of 60 SDSS-DR7 QSOs (Shen+, 2012)
J/MNRAS/423/600 : Type-1 low-z AGN emission properties (Stern+, 2012)
J/ApJ/737/71 : The [OIII] emission line in SDSS AGNs (Zhang+, 2011)
J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)
J/MNRAS/405/2302 : Improved redshifts for SDSS quasar spectra (Hewett+, 2010)
J/AJ/130/381 : Blueshifted [O III] emission (Boroson+, 2005)
http://www.sdss3.org/ : SDSS-III home page
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- RMID [0/848]? Unique RMID number (1)
5- 10 F6.4 --- z [0.1/4.4] Pipeline redshift (Z)
12- 18 F7.4 [10-7W] logL1350 [44.3/47]?=0 Continuum luminosity
at rest 1350Å, in erg/s (LOGL1350)
20- 25 F6.4 [10-7W] e_logL1350 [0.0003/0.03]? logL1350 uncertainty
27- 33 F7.4 [10-7W] logL1700 [44.1/47]?=0 Continuum luminosity
at rest 1350Å, in erg/s (LOGL1700)
35- 40 F6.4 [10-7W] e_logL1700 [0.0002/0.02]? logL1700 uncertainty
42- 48 F7.4 [10-7W] logL3000 [42.2/46.8]?=0 Continuum luminosity
at rest 3000Å, in erg/s (LOGL3000)
50- 55 F6.4 [10-7W] e_logL3000 [0.0001/0.04]? logL3000 uncertainty
57- 63 F7.4 [10-7W] logL5100 [42.6/45.7]?=0 Continuum luminosity
at rest 5100Å, in erg/s (LOGL5100)
65- 70 F6.4 [10-7W] e_logL5100 [0.0002/0.03]? logL5100 uncertainty
72- 79 F8.2 km/s VHb [-3025/3088]?=0 Peak velocity (wrt pipeline z)
for broad Hβ (HBETA_BR)
81- 87 F7.2 km/s e_VHb [2/2546]?=-1 VHb uncertainty (2)
89- 95 F7.2 km/s VOIIIc [-319/341]?=0 Peak velocity (wrt pipeline z)
for the core [OIII] (OIII5008C)
97-101 F5.2 km/s e_VOIIIc [0.9/83]?=-1 VOIIIc uncertainty (2)
103-109 F7.2 km/s VOIIIf [-906/760]?=0 Peak velocity (wrt pipeline z)
for the full [OIII] (OIII5008A)
111-117 F7.2 km/s e_VOIIIf [0.8/1227]?=-1 VOIIIf uncertainty (2)
119-126 F8.2 km/s VCaII [-1351/802]?=0 Peak velocity (wrt pipeline z)
for CaII (CAII3934)
128-133 F6.2 km/s e_VCaII [6/992]?=-1 VCaII uncertainty (2)
135-142 F8.2 km/s VOII [-1094/2085] Peak velocity (wrt pipeline z)
for [OII] (OII3728)
144-149 F6.2 km/s e_VOII [1/858]?=-1 VOII uncertainty (2)
151-158 F8.2 km/s VNeV [-2983/3013]?=0 Peak velocity (wrt pipeline z)
for [NeV]3426 (NEV3426)
160-166 F7.2 km/s e_VNeV [0.9/1035]?=-1 VNeV uncertainty (2)
168-175 F8.2 km/s VMgII [-2699/3292]?=0 Peak velocity (wrt pipeline z)
for MgII (MGII)
177-183 F7.2 km/s e_VMgII [8/2003]?=-1 VMgII uncertainty (2)
185-192 F8.2 km/s VCIII [-4513/4573]?=0 Peak velocity (wrt pipeline z)
for CIII] (CIII)
194-200 F7.2 km/s e_VCIII [8/4426]?=-1 VCIII uncertainty (2)
202-209 F8.2 km/s VComp [-8937/4573]?=0 Peak velocity (wrt pipeline z)
for the CIII]/SiIII]/AlIII complex (CIIIA)
211-217 F7.2 km/s e_VComp [8/4426]?=-1 VComp uncertainty (2)
219-226 F8.2 km/s VHeII [-2390/1963]?=0 Peak velocity (wrt pipeline z)
for HeII1640 (HEII1640)
228-234 F7.2 km/s e_VHeII [0.7/1634]?=-1 VHeII uncertainty (2)
236-243 F8.2 km/s VCIV [-4316/2226]?=0 Peak velocity (wrt pipeline z)
for CIV (CIV)
245-251 F7.2 km/s e_VCIV [6/2140]?=-1 VCIV uncertainty (2)
253-260 F8.2 km/s VSi/OIV [-2882/2744]?=0 Peak velocity (wrt pipeline z)
for SiIV/OIV] (SIIV)
262-267 F6.2 km/s e_VSi/OIV [11/843]?=-1 VSi/OIV uncertainty (2)
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Note (1): More information about the SDSS-RM sample can be found in the
technical overview paper (Shen+, 2015, J/ApJS/216/4).
Note (2): The uncertainty is -1 if the measurement is unavailable
(e.g., line not covered).
In the paper, we only used measurements with velocity uncertainties
<500km/s.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 23-Jan-2017