The optical-UV emissivity of quasars: dependence on black hole mass and radio loudness

0.26 MB·

by  Francesco Shankar

DRAFTVERSIONJANUARY12,2016
PreprinttypesetusingLATEXstyleemulateapjv.11/26/04
THEOPTICAL-UVEMISSIVITYOFQUASARS:DEPENDENCEONBLACKHOLEMASSANDRADIOLOUDNESS
FRANCESCOSHANKAR1,GIORGIOCALDERONE2,CHRISTIANKNIGGE1,JAMESMATTHEWS1,RACHELBUCKLAND1,KRZYSZTOF
HRYNIEWICZ3,GREGORYSIVAKOFF4,XINYUDAI5,KAYLEIGHRICHARDSON1,JACKRILEY1,JAMESGRAY1,FABIOLAFRANCA6,
DIEGOALTAMIRANO1,JUDITHCROSTON1,POSHAKGANDHI1,SEBASTIANHÖNIG1,IANMCHARDY1,MATTHEWMIDDLETON7
DraftversionJanuary12,2016
6
1 ABSTRACT
0
Weanalyzedalargesampleofradio-loudandradio-quietquasarspectraatredshift1.0≤z≤1.2tocompare
2
theinferredunderlyingquasarcontinuumslopes(afterremovalofthehostgalaxycontribution)withaccretion

an diskmodels.Thelatterpredictredder(decreasing)α3000continuumslopes(Lν∝ναat3000Å)withincreasing
blackholemass,bluerα withincreasingluminosityat3000Å,andbluerα withincreasingspinofthe
J 3000 3000
blackhole,whenallotherparametersareheldfixed. Wefindnoclearevidenceforanyofthesepredictionsin
8
thedata.Inparticularwefindthat:(i)α showsnosignificantdependenceonblackholemassorluminosity.
3000
Dedicated Monte Carlo tests suggest that the substantial observational uncertainties in the black hole virial
]
A massescaneffectivelyeraseanyintrinsicdependenceofα onblackholemass,inlinewithsomeprevious
3000
studies. (ii) The mean slope α of radio-loud sources, thought to be produced by rapidly spinning black
G 3000
holes, is comparableto, or evenredder than, thatof radio-quietquasars. Indeed, althoughquasarsappearto
.
h becomemoreradioloudwithdecreasingluminosity,westilldonotdetectanysignificantdependenceofα3000
p onradioloudness. Thepredictedmeanα3000 slopestendtobebluerthaninthedata. Diskmodelswithhigh
- inclinationsand dustextinctiontend to produceredderslopescloser to empiricalestimates. Our meanα
3000
o
valuesareclosetotheonesindependentlyinferredatz<0.5suggestingweakevolutionwithredshift,atleast
r
t formoderatelyluminousquasars.
s
a Subjectheadings:galaxies:active—galaxies:jets—quasars:general
[

1 1. INTRODUCTION the peak will shiftto higherfrequencieswith increasingUV
v luminosity,andthespectralslopeα willbecomebluer.Fi-
The current accretion paradigm on compact objects (from 3000
1 nally,atfixedblackholemassandaccretionrate,thepeakwill
stellarsourcestosuper-massiveblackholes)assumesthatin-
2
shifttohigherfrequencieswithdecreasingR (i.e.increas-
0 falling matter will settle in a rotating disk in which the gas ISCO
ingblackholespin),andtheslopeatUVwavelengthsisagain
2 looses its angular momentum via dynamical friction. The
expectedtobecomebluer(see,e.g.,Figure2inDavis&Laor
0 diskisusuallyassumedtobegeometricallythinandoptically
2011).
. thick (Shakura&Sunyaev 1973), i.e., each annulus radiates
1 According to some popular models (e.g.,
asablackbodywhosetemperaturedependsonitsradius.The
0 Blandford&Znajek 1977), powerful jets are produced
resultingspectrumshowsabroadpeakatacharacteristicen-
6 by rapidly spinning black holes. In this framework, the
ergyrelated to the temperatureat the inner radiiof the disk.
1
spectral properties of radio-loud and radio-quietquasars are
: InActiveGalacticNuclei(AGN)thediskspectrumpeaksin
v the UV/soft X-rays (the “Big Blue Bump”, e.g., Franketal. expected to show significant differences, and may provide
i valuableinsightsfortestingtheoreticalexpectations.
X 2002).
ThemainpurposeofthisletteristocomparetheAGNUV
Thediskmodelspectraareself–similarinlogarithmicνLν
r spectralslopeswithpredictionsofstandardthin-diskmodels
a plots,andthelocationofthepeakdependsontheblackhole
usingan improvedmethodtomeasurethequasarcontinuum
mass,theaccretionrate,andthelocationoftheinnermoststa-
appliedtoaverylargesample.
ble circular orbit(R , related to black hole spin). In par-
ISCO
ticular, at fixed accretion rate and RISCO, the peak will shift 2. DATA
to lower frequencieswith increasingblackhole mass. Since
ThequasarsampleusedinthisworkisasubsetoftheSDSS
thepeakisexpectedtolieatwavelengths.3000Å,thepeak
DR7quasarsamplediscussedinSchneideretal.(2010). The
shiftresultsinareddening(decrease)ofthespectralslopeat
spectral properties of this sample are discussed in the cat-
3000Å(α ,Eq.1).Also,atfixedblackholemassandspin,
3000 alog by Shenetal. (2011). However, we re-analyzed all
sources with z < 2 to better account for the host galaxy
1Department of Physics and Astronomy, University of Southampton,
and the iron complex contributions on each spectrum, and
Highfield,SO171BJ,UK;[email protected]
2INAF–Osservatorio Astronomico diBrera, viaE.Bianchi 46, I-23807 to identify the actual broad band AGN continuum. The de-
Merate(LC),Italy;[email protected] tails will be presented in a forthcomingpaper (Calderone et
3ISDCDataCentreforAstrophysics,ObservatoiredeGenève,Université al. 2016, in preparation), but we provide a brief description
deGenève,Chemind’Ecogia16,1290Versoix,Switzerland here: the SDSS DR10 spectrum of each source is fitted via
4DepartmentofPhysics,UniversityofAlberta,CCIS4-183,Edmonton, a model that includes the quasar continuum (modeled as a
AlbertaT6G2E1,Canada
5HomerL.DodgeDepartmentofPhysicsandAstronomy,Universityof smoothly broken power law), an elliptical host galaxy tem-
Oklahoma,Norman,OK73019,USA plate (Mannuccietal. 2001), an optical (Véron-Cettyetal.
6DipartimentodiMatematicaeFisica,UniversitádegliStudiRomaTre, 2004) and UV (Vestergaard&Wilkes 2001) iron template,
viadellaVascaNavale84,00146Roma,Italy
anda list of commonbroadand narrowemission lines. The
7InstituteofAstronomy,MadingleyRoad,CambridgeCB30HA,UK
smoothlybrokenpowerlawextendsovertheentireobserved
2
FIG.1.—Meanα3000asafunctionoftheluminosityat3000Å(restframe)forblackholesintherange7.7<logMbh/M⊙<8.3(left),8.3<logMbh/M⊙<8.8
(middle),and9.0<logMbh/M⊙<9.5(right).Thesolid,purplelinesmarkthepredictionoftheShakura&Sunyaev(1973)diskmodelforanon-rotating,zero
spinblackholewithmasslogMbh/M⊙=8.0,8.5,9.25fortheleft,middle,andrightpanels,respectively. Thesolid,greenlinesshowtheresultsofthesame
blackbodymodelsformaximallyspinningblackholes. ModelsareplotteduptotheEddingtonlimitcorresponding tothemeanblackholemasslabeled in
eachpanel.Allradio-loudsourcestendtohaveα3000comparabletothoseofradio-quietquasarsatthehighestluminositybins,i.e.,logL3000/ergs- 1>45,and
systematicallyredderatprogressivelylowerluminosities. Thehorizontaldottedlinesmarkthecanonicalaccretiondiskslopeatwavelengthssignificantlonger
thanthepeakwavelengthforastandardaccretiondiskmodel.ThefilledblacksquaresaredataderivedbyDavis&Laor(2011)fromasampleofopticalquasars
atz<0.5.
wavelength range, providing a reasonable estimate of the We willspecificallyselectsourceslyingin theredshiftin-
actual AGN continuum. The host galaxy template is cho- terval 1.0<z<1.2. This redshift window allows for more
sen to be that of an elliptical galaxy since such galaxies accuratemeasurementsof theSDSS optical-UVquasarcon-
are those usually observedto be the hosts of massive, lumi- tinuum spectra around 3000Å. As detailed in Calderone et
nous black holes, based on direct photometric studies (e.g., al. (2016) in fact, spectral slopes measured with our proce-
Falomoetal.2014)andlocalscalingrelations(e.g.,Shankar dure on quasars with z<1.0 or z>1.3 may be biased due
2009;Kormendy&Ho2013). to the limited SDSS wavelength spectral coverage. Finally,
Ourcatalogthuscontainsupdatedcontinuum(isotropic)lu- Malmquistbiaseffectsandreddening/extinctionbyinterven-
minosities and slopes with respect to the Shenetal. (2011) ingcosmicdust(Xieetal.2015)couldbecomeincreasingis-
one, where the host galaxy and iron contributions were ne- suesathigherredshiftsand/orlargerredshiftbins,furtherbi-
glected. Note that our luminosity and slopes estimates are asingthetruedistributionsofα .
3000
measuredonthesmoothlybrokenpowerlawcomponentthat
3. DISKMODELS
extendsoverthewholerest-frameobservedwavelengthrange.
This implies that the slopes are evaluated on a wider wave- We compare our data with predictions of the non-
lengthrangewithrespecttoShenetal.(2011). relativistic, steady-state, geometrically thin, optically thick
Thepurposeofour spectralanalysisis to estimate the un- standardaccretiondiskShakura&Sunyaev(1973). Inbrief,
derlyingquasarcontinuumslopeα definedasfollows: the model first computes the amount of gravitational en-
3000
ergy ζ(R) released from each disk annulus of size 2πRdR
dlogLν and, underthe assumptionofopticalthickness, itconvertsit
α = , (1)
3000 dlogν into a blackbodytemperatureT(R)∝ζ(R)1/4. The expected
frequency-dependentluminosityLν isthencomputedasasu-
calculatedat3000Å(sourcerestframe). perpositionofblackbodyspectraB[ν,T(R)].Thephysicalin-
In the following we will consider several sub–samples of putparametersin the standarddisk modelare the innermost
the original Schneideretal. (2010) sample according to ei- stablecircularorbitR ,directlylinkedtothespin/radiative
isco
ther: thevirialblackholemassaslistedinShenetal.(2011) efficiency, the black hole mass M , and the mass accretion
bh
derived mainly from MgII in the redshift range of interest rateM˙ (e.g.,Thorne1974;Calderoneetal.2013,andrefer-
acc
to this work; the continuumluminosityandslopesat 3000Å encestherein).
(restframe)accordingtotheresultsofournewspectralanal- WealsocompareourmainobservationalresultswithAGN-
ysis;andtheradioloudnessR= f6cm/f2500(Jiangetal.2007) SPEC (Hubeny&Hubeny 1997; Hubenyetal. 2000, 2001),
defined as the ratio between the flux density (fν) at 6 cm a self-consistent numerical model for AGN disk spectra as
and 2500Å rest-frame respectively, available for all SDSS viewedbyanobserveratagivenanglewithrespecttotheaxis
quasarsmatchedagainsttheFaintImagesoftheRadioSkyat ofrotation.Themodelproperlyconsidersdeparturesfromlo-
Twenty-Centimeters(FIRST)surveyat1.4GHz(Whiteetal. cal thermodynamic equilibrium, and takes into account the
1997). Wedevotespecificattentiontothedifferenceinspec- vertical structure of the disk, as well as relativistic Doppler
tralslopesbetweenradio-quietquasars,lyingwithinthefoot- shifts, gravitational redshifts and light bending in a rotating
print of FIRST but with R=0, and very radio-loud sources spacetime (Hubenyetal. 2000). The direct comparison be-
with R > 100, though the exact threshold chosen for radio tweenthepredictionsfrombasicdiskmodelsandAGNSPEC
loudnessdoesnotalteranyofourconclusions.Wealsobriefly willallowustopindownwhichadditionalfeaturesfromthe
mention results based on “radio morphology”as reportedin latter (more realistic) models are essential in describing the
Shenetal.(2011),inwhichradio-loudquasarsarebroadlydi- UVspectraofquasars.
videdinto“FR1”and“FR2”sources(Fanaroff&Riley1974), For completeness, all model luminosities are convertedto
i.e. core– or lobe–dominated (see Jiangetal. 2007 for de- “isotropic equivalent” (e.g., Calderoneetal. 2013) via 1+
tails). cosi with i the maximum viewing angle. Unless other-
3
FIG.2.—StackedSDSSspectraofquasarswithblackholemassesintherange8.3<logMbh/M⊙<8.8,intheredshiftwindow1.0<z<1.2,andnormalized
at3000Å.Weincluderadio-quiet,core-dominatedFR1,andlobe-dominatedFR2radiosources,aswellasradio-loudquasarswithR>10,fortwointervalsof
L3000luminosity,aslabeled.Itisapparentthatallradio-loudsources,irrespectiveoftheirexactclassifications,showflatterprofilesthanradio-quietquasars.
wise noted, in the following we will assume i = 45◦ (e.g., Thedifferencesinα betweenradio-loudandradio-quiet
3000
Urry&Padovani1995). quasars,inparticular,arenotanartifactoftheexactspectral
fittingprocedureand/orontheexactdefinitionofradioloud-
4. RESULTS ness. Indeed,suchsystematicdifferencesarealreadyclearly
evidentdirectly on the stacked spectra. Figure 2 reportsthe
Figure 1 shows the mean (and standard deviation of the
stacked spectra of radio-quiet and radio-loud quasars with
mean) α3000 as a function of the luminosity at 3000Å (rest black hole masses in the range 8.3<logMbh/M⊙ <8.8 at
frame) for black holes in the range 7.7 < logMbh/M⊙ < 1.0<z<1.2, and normalized at 3000Å. Irrespective of the
8.3 (left), 8.3 < logMbh/M⊙ < 8.8 (middle), and 9.0 < exactsubsampleofradiosources,eitherFR1,FR2,orsimply
logMbh/M⊙<9.5(right).Wechosebins(inblackholemass based on their radio loudness (here we report sources with
and/orluminosity)sufficientlylargeto enhancestatistics but
R>10 to increase the statistics), all radio-detected sources
stillsmallenoughtoprovidemultiplebinsacrossourparame-
showsystematicallyredderprofiles(lowerα )withrespect
terspace.Wenotethatnoneofourresultsdependontheexact 3000
to their radio-quietcounterparts. This differenceis however
binning. Inthisandallsubsequentfigures,thetotalnumbers
more marked for less luminoussources(left panel), while it
of radio-quiet (red, long-dashed lines) and radio-loud (blue,
progressivelydisappearsforbrightersources(rightpanel),in
solid lines) sources is indicated in the legend of each plot.
agreementwithFigure1.
All our data gather around rather constant mean slopes of
Figure3furthercomparesmodelpredictionsagainstSDSS
- 0.5<α <- 0.3,quiteindependentlyofblackholemass,
3000 data by specifically plotting the behaviorof α as a func-
luminosity,or the quasar radiostate. Mostof the radio-loud 3000
tionofblackholemassforquasarsinthenarrowbinsofop-
sources share α3000 slopes very close to those of radio-quiet tical luminosity 44.75<logL /ergs- 1 <45.25 (left) and
snoousritcieessobfelsoiwmilloagrLblack/ehrogles-m1a.ss4a5nrdadluiomsionuorsciteys.mAatylutemnid- 45.5<logL3000/ergs- 1 <46.3000(0right). Our measured α3000
3000 isratherflat,orevenslightlybluerwithincreasingblackhole
towardsevenredderspectra(lowerα3000). Wealsonotethat massintherange- 0.6<α <- 0.2,inniceagreementwith
themeanα3000valuesextractedfromourdataagreewellwith thevaluesforαbetween23200000- 4000 inferredbyDavisetal.
thosederivedatz<0.5byDavis&Laor(2011)forasample
(2007, their Figure 3), who also emphasized very weak de-
of80PGmeasuredintheintervalbetween4816Åand1549Å,
pendenceonblackholemass. Similarly,Selsingetal.(2015)
atleastatlowerluminosities,suggestinglittleredshiftevolu-
recentlyconstructedacompositespectrumforveryluminous
tionintheoptical-UVspectralpropertiesofquasars.
quasars at 1<z<2.1 from UV to near-infrared deriving a
Wecompareourmeasurementswiththepredictionsofthe meanslopeofα=- 0.3.
Shakura&Sunyaev (1973) disk model for a non-rotating,
As anticipated in Figure 1 the standard disk models (up-
zero spin (red lines) and maximally spinning (green lines)
per panels) with zero and maximalspin (magentaand green
black holes of same mass and luminosity. As already em-
dottedlines)predictasteadyreddeningofα withincreas-
3000
phasizedbyanumberofpreviousgroups(e.g.,Bonningetal.
ing black hole mass at fixed luminosity. The substantialun-
2007; Davisetal. 2007; Laor&Davis 2014, and references
certainties in virial black hole mass estimates of &0.5 dex
therein),theresultsofdirectquasarspectralfittingsareoften
(e.g., Shen&Liu 2012, and references therein), could how-
at variance with the theoretical expectationsof the thin disk
everhaveanon-negligibleimpactonthecomparisonbetween
model. Our measurementsfurtherreinforcethis by pointing
models and data. To probe this, we performed a series of
toratherconstantmeanα values,inapparentconflictwith
3000 MonteCarlotests. Westartedbyrandomlyextractingavery
basicpredictionsfromstandardaccretiondisktheorythatre-
largenumberofblackholesfromtheType1correctedactive
quires a significant drop of α3000 at fixed optical luminosity black hole mass function at z∼1 by Schulzeetal. (2015).
whenmovingfromlowto high-massblackholes, asevident
To these we associated an Eddington ratio λ=logL /L
bol Edd
fromthemodelsreportedinFigure1whenmovingfromthe
taken from a power-law with broad exponential cut-off dis-
lefttotherightpanel.
4
FIG.3.—Meanα3000forradio-quietandradio-loudsourcesasafunctionofblackholemassintwodifferentluminositybins,44.75<logL3000/ergs- 1<45.25
(left)and45.5<logL3000/ergs- 1<46.0(right),aslabeled.ThedataintheupperandlowerpanelsarecomparedwithShakura&Sunyaev(1973)andAGNSPEC
diskmodels,respectively(seeSection3). Themagentaandgreenlinesinallpanelsrefertomodelswithzeroandmaximumspinrespectively. Thedottedand
solidlinesintheupperpanelsrefer,respectively,totherawmodeloutputsandtotheMonteCarlosimulationsinclusiveofstatisticalerrorsinblackholemass
andluminosity(seetextfordetails). Thesolidandlong-dashedlinesinthelowerpanelsinsteadarefromMonteCarlosimulationswithlow(10◦)andextreme
inclinations(70◦),respectively.
tribution (Shankaretal. 2013), typical of AGN at these red- in good agreementwith those from basic blackbodymodels
shifts (e.g., Bongiornoetal. 2012). We also experimented (solid lines in the upper panels), while the predicted α
3000
with different shapes for the underlying black hole mass slopestendtosignificantlydecreasewhenassumingprogres-
function or Eddington ratio distribution without finding any sively higher inclinations. Interestingly, we identified a de-
strong change in the main outcomes of our tests. Bolo- generacyamongmodelscharacterizedbylowinclination/low
metric luminosities were then converted to L adopting spin and high inclination/high spin (purple solid and green
3000
the quasar bolometric corrections by Runnoeetal. (2012), dot-dashedlines,respectively).Whilehighspinmodelsshow
logL =0.75×(0.97logL +1.85).Wethenranafewhun- bluer α slopes due to the smaller inner disk radius, the
bol 3000 3000
dredrealizationsassigningateachiterationrandomGaussian redderUV slopes forviewing anglesnearthe disk planeare
errors to black hole masses and luminosities with widths of mostlyduetolimbdarkeningeffects.
0.6dexand0.1dex,respectively,andthencomputedthere- We havealsocheckedthatincludingdustextinctioninthe
sultingmeanα overallrealizationsasafunctionofblack predicted quasar spectra yields redder spectra further con-
3000
holemassandluminosity. Theresultsofthetest, markedby tributingtothedegeneracywithinclinationandspin. Inpar-
solid,magentaandgreenlinesintheupperpanelsofFigure3, ticular,modelingtheextinctioncurveasA(λ)=0.06(5500/λ)
showthatα “flattensout”,becomingsignificantlybluerat (e.g., Capellupoetal. 2015) yields ∆α ∼ 0.1. Higher
3000 3000
largeblackholemasses,aligningbetterwiththedata(though values of the extinction in quasars are also possible (e.g.,
stillpredictingbluerslopes,especiallyathigherluminosities). Stern&Laor 2012). Rapidly spinning black holes need in
Thisisexpectedgiventhesignificantlyhighernumberdensi- generalhighinclinationsi&50◦withsomedegreeofextinc-
ties of lower mass black holes coupledto the large errorsin tiontomatchthedata.Blackholeswithretrogradespinsmay
black hole masses assumed in the tests. These results agree alsoyieldredderslopes.
well with those by Davisetal. (2007) who also showed that Other systematics may arise fromadoptingdifferentinput
large errorsin black hole virial masses can effectively erase galaxy spectra. To check for this effect, we randomly se-
mostofthedependenceofUVslopesonblackholemass. lectedquasarsubsamplesofdifferentblackholemassandlu-
ThelowerpanelsofFigure3showthecomparisonsofour minosityat1<z<1.2,andrefittedthequasarspectraadopt-
data with the AGNSPEC disk predictions with two extreme ing the star-forming host galaxy template of Arp220 (e.g.,
values of the input inclinations (i = 10◦ and i = 70◦, solid Pollettaetal.2007). Despitethistemplatebeingmorepromi-
and long-dashed lines, respectively). We verified that mod- nent in the UV with respect to our reference elliptical tem-
els with more realistic random input orientations fall within plate(Section2),wefoundresultingslopesonaveragebluer
these two extreme cases. Models with low inclinations are byarelativelymodest∆α ∼0.05- 0.15.Thiseffectcould
3000
5
FIG.4.—Left:Meanradioloudnessasafunctionofbolometricluminosity(asreportedbyShenetal.(2011))fordifferentbinsofblackholemassaslabelled.
Right: Meanα3000asafunctionofradioloudnessRfordifferentbinsofblackholemass,aslabeled. Whilequasarsbecomemoreradio-loudwithdecreasing
luminosity,thereisnocleardependenceofα3000onR.
anywaybesignificantlyreducedbyextinction. quasars, they would in fact be expected to show bluer UV
We finally note that the complexities behind the exact slopes (Section 1), in contrast to our data. Interestingly,
modelingofabsorption/emissionfeaturessuchasthosefrom Punsly(2014)hasalsoreporteda“deficit”intheUVspectra
FeII/III groups, may limit the precision of our continuum ofradio-loudquasarsbetween1100Åand580Å,whichmight
measurements,thoughwedonotexpectthemtosignificantly reflectwhatweobserveinSDSSatlongerwavelengths.Ifthis
alteranyofourresults. spectraldistortionislinkedtolocalenergydissipationduetoa
In Figure 4 we further investigatethe connectionbetween large-scalemagneticflux(Punsly2014),itshouldmoderately
spectraandradioloudnessinspecificallyradio-loudquasars. scalewiththespinand/orradioloudness,whilenoclearcorre-
Therearecleartrends(leftpanel)thatthemeanradioloudness lationisdetectedinourdatabetweenα andradioloudness
3000
R decreases with increasing luminosity, and thus ultimately (Figure4). Additionalcausesforaweakspectraldependence
accretion rate (e.g., Sikoraetal. 2007, 2013). These trends on spin and general spectral distortions may be related to
holdirrespectiveofthe exactblack holemass or redshiftin- AGN wind losses (e.g., Laor&Davis 2014; Slone&Netzer
terval. However,theslopeα3000 (rightpanel)showsnoclear 2012).
dependence on radio loudness R, at least for the radio-loud There are a number of cases in which the
quasarsintheinterval1<z<1.2. Shakura&Sunyaev (1973) models have been success-
fully applied to describe quasar spectra (Shields 1978;
5. DISCUSSION Kishimotoetal. 2008; Capellupoetal. 2015). However, our
Our analysis of quasar spectra at z∼1 pointed to rather resultsadd to the mountingevidencefor some disagreement
constant and red mean values of the UV slope in the range between standard disk models and data derived from direct
- 0.5<α <- 0.3 with a mild dependence on black hole spectral fitting (e.g., Bonningetal. 2007; Davisetal. 2007;
3000
mass. This (lackof) trend, we showed, is mostprobablyin- Slone&Netzer 2012), quasar microlensing (e.g., Daietal.
ducedby the significantuncertaintiesin blackhole mass es- 2010), or lags measured from correlated X-ray/UV/optical
timates(Figure3), while includinghighinclinationsandex- monitoringofAGN(e.g.,McHardyetal.2014).
tinctioncanalignthepredictedα totheredderslopesde-
3000
rivedfromthedata.
We also find that the vast majority of radio-loud quasars
ACKNOWLEDGMENTS
havecomparableor evenredderα slopeswith respectto
3000
opticalquasarsofsimilarblackholemassandaccretionrate. WethankIvanHubenyandEricAgolfortheirAGNSPEC
This finding is of particular interest to the still unsolved is- and Kerrtrans9 codes and Omar Blaes for general help. We
sue of the origin of radio-loudness (e.g., Sikoraetal. 2007; warmlythankShaneDavisandAriLaorforveryusefulcom-
Kördingetal. 2008; Merloni&Heinz 2008; Shankaretal. ments and for sharing their data. We also thank Gordon
2010; Kratzer&Richards 2015). If radio-loud quasars are Richardsfordiscussionsandananonymousrefereeforhelp-
characterizedbysystematicallyhigherspinsthanradio-quiet fulcommentsthatimprovedtheclarityofthepaper.
REFERENCES
Blandford,R.D.,&Znajek,R.L.1977,MNRAS,179,433 Frank,J.,King,A.,&Raine,D.J.2002,AccretionPowerinAstrophysics:
Bongiorno,A.,Merloni,A.,Brusa,M.,etal.2012,MNRAS,427,3103 ThirdEdition
Bonning,E.W.,Cheng,L.,Shields,G.A.,Salviander, S.,&Gebhardt, K. Hubeny,I.,Agol,E.,Blaes,O.,&Krolik,J.H.2000,ApJ,533,710
2007,ApJ,659,211 Hubeny,I.,Blaes,O.,Krolik,J.H.,&Agol,E.2001,ApJ,559,680
Calderone, G., Ghisellini, G., Colpi, M., & Dotti, M. 2013, Hubeny,I.,&Hubeny,V.1997,ApJ,484,L37
MNRAS,431,210 Jiang,L.,Fan,X.,Ivezic´,Ž.,etal.2007,ApJ,656,680
Capellupo,D.M.,Netzer,H.,Lira,P.,Trakhtenbrot,B.,&Mejía-Restrepo, Kishimoto,M.,Antonucci,R.,Blaes,O.,etal.2008,Nature,454,492
J.2015,MNRAS,446,3427 Körding,E.G.,Jester,S.,&Fender,R.2008,MNRAS,383,277
Dai,X.,Kochanek,C.S.,Chartas,G.,etal.2010,ApJ,709,278 Kormendy,J.,&Ho,L.C.2013,ARA&A,51,511
Davis,S.W.,&Laor,A.2011,ApJ,728,98 Kratzer,R.M.,&Richards,G.T.2015,AJ,149,61
Davis,S.W.,Woo,J.-H.,&Blaes,O.M.2007,ApJ,668,682 Laor,A.,&Davis,S.W.2014,MNRAS,438,3024
Falomo, R., Bettoni, D., Karhunen, K., Kotilainen, J. K., & Uslenghi, M. Mannucci,F.,Basile,F.,Poggianti,B.M.,etal.2001,MNRAS,326,745
2014,MNRAS,440,476 McHardy,I.M.,Cameron,D.T.,Dwelly,T.,etal.2014,MNRAS,444,1469
Fanaroff,B.L.,&Riley,J.M.1974,MNRAS,167,31P Merloni,A.,&Heinz,S.2008,MNRAS,388,1011
6
Polletta,M.,Tajer,M.,Maraschi,L.,etal.2007,ApJ,663,81 Sikora, M., Stasin´ska, G., Kozieł-Wierzbowska, D., Madejski, G. M., &
Punsly,B.2014,ApJ,797,L33 Asari,N.V.2013,ApJ,765,62
Runnoe,J.C.,Brotherton,M.S.,&Shang,Z.2012,MNRAS,422,478 Sikora,M.,Stawarz,Ł.,&Lasota,J.-P.2007,ApJ,658,815
Schneider,D.P.,Richards,G.T.,Hall,P.B.,etal.2010,AJ,139,2360 Slone,O.,&Netzer,H.2012,MNRAS,426,656
Schulze,A.,Bongiorno,A.,Gavignaud,I.,etal.2015,MNRAS,447,2085 Stern,J.,&Laor,A.2012,MNRAS,423,600
Selsing,J.,Fynbo,J.P.U.,Christensen,L.,&Krogager,J.-K.2015,ArXiv Thorne,K.S.1974,ApJ,191,507
e-prints,arXiv:1510.08058 Urry,C.M.,&Padovani,P.1995,PASP,107,803
Shakura,N.I.,&Sunyaev,R.A.1973,A&A,24,337 Véron-Cetty,M.-P.,Joly,M.,&Véron,P.2004,A&A,417,515
Shankar,F.2009,NewAstron.Rev.,53,57 Vestergaard,M.,&Wilkes,B.J.2001,ApJS,134,1
Shankar, F., Sivakoff, G. R., Vestergaard, M., & Dai, X. 2010, White,R.L.,Becker,R.H.,Helfand,D.J.,&Gregg,M.D.1997,ApJ,475,
MNRAS,401,1869 479
Shankar,F.,Weinberg,D.H.,&Miralda-Escudé,J.2013,MNRAS,428,421 Xie,X.,Shen,S.,Shao,Z.,&Yin,J.2015,ApJ,802,L16
Shen,Y.,&Liu,X.2012,ApJ,753,125
Shen,Y.,Richards,G.T.,Strauss,M.A.,etal.2011,ApJS,194,45
Shields,G.A.1978,Nature,272,706