NASA Technical Reports Server (NTRS) 20150002691: The Suzaku View of Highly Ionized Outflows in AGN. 1; Statistical Detection and Global Absorber Properties

1.2 MB·English

by  NASA Technical Reports Server (NTRS)

MNRAS Advance Access published January 21, 2013
MNRAS(2013) doi:10.1093/mnras/sts481
The Suzaku view of highly ionized outflows in AGN – I. Statistical
detection and global absorber properties
Jason Gofford,1‹ James N. Reeves,1,2 Francesco Tombesi,3,4 Valentina Braito,5,6
T. Jane Turner,2 Lance Miller7 and Massimo Cappi8
1AstrophysicsGroup,KeeleUniversity,KeeleST55BG,UK
2DepartmentofPhysics,UniversityofMarylandBaltimoreCounty,Baltimore,MD21250,USA
3X-rayAstrophysicsLaboratoryandCRESST,NASA/GSFC,Greenbelt,MD20771,USA
4DepartmentofAstronomy,UniversityofMaryland,CollegePark,MD20742,USA
5INAF-OsservatorioAstronomicodiBrera,ViaBianchi46,I-23807Merate,Italy
6DepartmentofPhysicsandAstronomy,UniversityofLeicester,UniversityRoad,LeicesterLE17RH,UK
7DepartmentofPhysics,OxfordUniversity,DenysWilkinsonBuilding,KebleRoad,OxfordOX13RH,UK
D
8INAF-IASFBologna,ViaGobetti101,I-40129Bologna,Italy o
w
n
lo
a
d
e
Accepted2012November22.Received2012November22;inoriginalform2012October14 d fro
m
h
ttp
ABSTRACT ://m
WepresenttheresultsofanewspectroscopicstudyofFeK-bandabsorptioninactivegalactic n
ra
nuclei (AGN). Using data obtained from the Suzaku public archive we have performed a s.o
statisticallydrivenblindsearchforFeXXVHeαand/orFeXXVILyαabsorptionlinesinalarge xfo
sample of 51 Type 1.0−1.9 AGN. Through extensive Monte Carlo simulations we find that rdjo
u
statisticallysignificantabsorptionisdetectedatE(cid:2)6.7keVin20/51sourcesatthePMC ≥ rna
95percentlevel,whichcorrespondsto∼40percentofthetotalsample.Inallcases,individual ls.o
absorption lines are detected independently and simultaneously amongst the two (or three) arg/
available X-ray imaging spectrometer detectors, which confirms the robustness of the line t N
A
detections. The most frequently observed outflow phenomenology consists of two discrete S
A
absorptiontroughscorrespondingtoFeXXVHeαandFeXXVILyαatacommonvelocityshift. G
o
FromxstarfittingthemeancolumndensityandionizationparameterfortheFeKabsorption dd
a
components are log(N /cm−2) ≈ 23 and log(ξ/ergcms−1) ≈ 4.5, respectively. Measured rd
H S
outflow velocities span a continuous range from <1500 km s−1 up to ∼100000 km s−1, pa
c
withmeanandmedianvaluesof∼0.1cand∼0.056c,respectively.Theresultsofthiswork e F
areconsistentwiththoserecentlyobtainedusingXMM–Newtonandindependentlyprovides ligh
sfrtarocntigonevoifdebnocthefroadritoh-eqeuxieistteanncderoadfivoe-rlyouhdigAhlGyNioinniztehdecloirccaulmunniuvcelresaer.materialinasignificant t Ctr on
A
p
Keywords: line:identification–galaxies:active–galaxies:nuclei–X-rays:galaxies. ril 5
, 2
0
1
3
gravitational radii (R = GM/c2) in size (Morgan et al. 2008;
1 INTRODUCTION g
Chartas et al. 2009; Dai et al. 2010) and so the spectral analysis
Observational evidence for outflows and winds in active galactic of absorption features imprinted on the X-ray continuum by cir-
nuclei (AGN) is seen in multiple energy regimes, ranging from cumnuclear material in an AGN is a powerful diagnostic of the
the prominent radio-jets seen in radio-loud sources, to the broad physicalconditionsoftheenvironmentinthevicinityofthecen-
absorptionlinesobservedinbroadabsorptionline(BAL)quasars, tralsuper-massiveblackhole(SMBH),ofthedynamicsandkine-
through to the photoionized ‘warm absorber’ which is frequently matics of the outflowing material, its chemical composition and
observed in the soft X-rays (e.g. Crenshaw, Kraemer & George its ionization state. Understanding how such winds are formed,
2003;Blustinetal.2005;McKernan,Yaqoob&Reynolds2007). their physical characteristics and their energetic output are of vi-
Gravitational micro-lensing studies have shown that the primary tal importance when it comes to studying how the interplay be-
X-ray emission region in AGN is of the order of a few tens of tweentheaccretionandejectionflowsatsmallradiicanaffectthe
hostgalaxyonlargerscales(e.g.Ferrarese&Merritt2000;King
& Pounds 2003; Sazonov et al. 2005; Ciotti, Ostriker & Proga
(cid:4)E-mail:[email protected] 2009).
(cid:5)C 2013TheAuthors
PublishedbyOxfordUniversityPressonbehalfoftheRoyalAstronomicalSociety
2 J.Goffordetal.
IntheX-rayregimethepresenceofphotoionizedmaterialinAGN sorptionfeatures–pointtoanoriginmorelikelyassociatedwitha
iswellestablished,withatleast50percentofobjectsshowingdirect windwhichislaunchedfromthesurfaceoftheaccretiondiscitself
spectroscopicevidencefordiscreteabsorptionlinesandphotoelec- (e.g.Poundsetal.2003b;Reevesetal.2009;Goffordetal.2011;
tric edges in their soft-band (E < 3 keV) spectra (e.g. Reynolds Tombesietal.2012).Inthisscenariotheinferredmassoutflowrates
1997;Crenshawetal.2003;Blustinetal.2005),withtypicalline- fordiscwindsareoftencomparabletothoseofthematterwhich
of-sightvelocitiesrangingfromafewhundredtoaroundathousand accretesontothecentralblackholeandtheconsequentmechani-
kms−1(Blustinetal.2005;McKernanetal.2007).Detailedmod- calpowercanalsobeasizeablefraction(i.e.≥fewpercent)ofan
ellingathighspectralresolutionwithphotoionizationcodessuchas AGN’sbolometricluminosity(e.g.Chartasetal.2002;Poundsetal.
xstar(Kallmanetal.2004)oftenfindsthesoft-bandabsorberto 2003b;Gibsonetal.2005;Reevesetal.2009;Goffordetal.2011;
bedescribedbycolumndensitiesandionizationparameters1inthe Tombesietal.2012)makingthemapromisingmeansoflinkingthe
range of log(N /cm−2)∼20−23 and log(ξ/ergcms−1)∼0−3, small-andlarge-scaleprocessesatplayingalacticevolutionover
H
respectively.Theseparametersimplythatthewarmabsorbersare cosmictime.
typically located on fairly large distances from the central black
hole,andperhapsassociatedwithawindoriginatingfromthepu-
1.1 WhySuzaku?
tative parsec scale torus (Blustin et al. 2005) or with the latter
stagesofanaccretiondiscwindwhichhaspropagatedouttolarger InthisworkweusearchivalSuzakuobservationsofalargesampleof D
radii(Proga&Kallman2004).Byvirtueoftheirlowoutflowve- AGNtocharacterizethepropertiesofhighlyionizedoutflowsinthe ow
locitiesthesoftX-raywarmabsorbersarethoughttoonlyhavea FeKband.Todate,themostcomprehensivestudyoftheseoutflows nlo
a
weakfeedbackeffectintheirhostgalaxy.Indeed,themechanical hasbeenconductedbyTombesietal.(2010a,hereafterT10A)who de
d
plooww,etryipmicpaalrlyted(cid:3)b0y.0i1ndpievridceunatlwofaramnaAbGsoNrp’stiboonlcoommeptroicnelnutmsiinsovseirtyy p4e2rsfoourmrceeds(awsiytshte1m01atoibcsnearrvraotwio-nbsa)nodb(tai.ien.e3d.5fr–o1m0.t5hkeeXVM)Man–aNlyeswistoonf from
(thLebo∼l)0(e.5.gp.eBrcluesnttinofetLbaoll.t2h0o0u5g)h,twnheiccehssiasrysigfonrififceaendtblyaclkowtoeraftfheacnt atirncuhuivme,inustihnegFaesKimbpalnedb.aTsheelinbeasmeloindeelmtooddeelsccorinbseistthedeoAfGaNpocwoner- http://m
the host galaxy (Hopkins & Elvis 2010). However, Crenshaw & law, narrow Gaussians and, where required, neutral absorption to n
Kraemer(2012)haverecentlyshownthatthis∼0.5percentthresh- approximateforanyspectralcurvature.Thisphenomenologicalap- ras.o
oldcanbeexceededprovidedthemechanicalpowerisintegrated proachyieldedafittothe4–10keVenergybandofmostsources xfo
oovfearfaelwlUmVodaenrdatXe--lruamyianbossoitryptlioocnalcAomGpNo.nents,atleastinthecase awnhdicFhewXXasVIsLufyfiαciaebnstotropteinoanbllienethsewsiythstoeumtanteiecdsienagrctohtoafkFeeadXdXiVtiHoneaαl rdjourn
ferMedobreyrXecMenMtl–yNtehwethoinghaenrdthSruozuagkhupautthaingdhelarrgXe-rraeyffeecnteivrgeieasre(aEo∼f- sappepcrtoraaclhcroemsupllteexditiyncinotnotiancucuomunpta.rMamoreeteorvsewr,hTic1h0Awefroeulnadrgtehlaytctohnis- als.o
rg
5–10keV)haveshownthatabsorption,specificallyintheformof sistentwiththosefoundbyauthorswhoconductedamorethorough a/
very highly ionized resonant absorption lines associated with the fit using the entire XMM–Newton bandpass. However, while this t N
K-shell(1s→2p)transitionsofFeXXVandFeXXVI,isalsomani- approachissuitableformostsourcesitisimportanttonotethatin AS
A
festedinthehardX-rayspectrumofasignificantfractionoflocal thosewhichhavemorecomplexX-rayspectra,e.g.thosewhichare G
AGN.Whileevidenceforsuchabsorptionlineswasinitiallycon- veryheavilyabsorbedorthosewithstronghardexcesses,usinga od
d
fined to detailed studies of individual sources (e.g. Pounds et al. narrow-band fit can yield a model which is a poor representation ard
2003b;Reeves,O’Brien&Ward2003;Risalitietal.2005;Turner ofthedatawhenextrapolatedtoconsiderthehigherandloweren- S
p
etal.2008;Cappietal.2009;Giustinietal.2011)therecentsys- ergies.Theonlywaytoovercomethislimitationisbyperforming ac
e
(te2m01a0tiac,a2r0c1h1ivaa,l2X01M2M)h–aNseswhtoownnsttuhdaytFceonXdXuVc–tXeXdVbIyabTsoomrpbtieosnielitnaels. aobdseetravialetodrbyrowahdi-cbhanodffaenrsalayssius.ffiScuizeanktluyisbrcouardrenbtalnydtphaesson(liy.e.X0-r.6ay– Fligh
ainrethperelsoecnatliunntihveeXrs-era(yzs<pe0c.t1r)a.oMfo(cid:2)r4eo0vpeerr,cseuncthoofurtafldoiow-squhiaevteAaGlsNo 5ex0ckeessV)antodathlleowCofomrptthoenerfefflecetcstioofnscooftm-bpaonndenatbstoorpbteiocno,ntshterasinoeftd- t Ctr on
been detected in a small sample of local broad line radio galax- simultaneously. This makes it the ideal instrument to confidently A
p
ies (BLRGs; Tombesi et al. 2010b, hereafter T10B) which thus constraintheunderlyingcontinuumandtorobustlyassessforthe ril 5
suggeststhattheymayrepresentanimportantadditiontothecom- presenceofhighlyionizedoutflowsinAGN. , 2
0
monlyheldAGNunificationmodel(e.g.Antonucci1993;Urry& 1
3
Padovani1995).
2 SAMPLE SELECTION
In comparison to the soft-band absorbers these hard X-ray
absorbers generally have much more extreme parameters, with The sample was selected from the Data Archive and Transmis-
log(NH/cm−2) ≈ 23–24 and log(ξ/ergcms−1) ≈ 3–6, and their sion System2 (DARTS; Tamura et al. 2004) which contains all
outflowvelocitiesrelativetothehostgalaxycanreachmildlyrela- publiclyavailableSuzakuobservationscategorizedbytheclassifi-
tivisticvalues.Whilealternativeexplanationshavebeenpositedin cation ofthetargetsource.AninitialsampleofAGN was drawn
the literature, e.g. resonant absorption by highly ionized material bypositionallycross-correlatingthetargetedpointingcoordinates
inacorotatingandopticallythinplasmaabovetheaccretiondisc ofallpubliclyavailable(asoftheendof2011December)Suzaku
(Gallo & Fabian 2011), the large inferred velocities – combined observations of extragalactic compact sources against the known
withtheshorttime-scalevariabilitysometimesexhibitedbytheab- positions of sources contained in the VERONCAT catalogue of
Quasars&AGN(Ve´ron-Cetty&Ve´ron2010).TheVERONCAT
hasanextensivelistoflocalAGN,allofwhichhavebeenquan-
1Theionizationparameterisdefinedasξ =Lion/nR2 (Tarter,Tucker& titatively classified based upon their optical properties using the
Salpeter1969),whereLion isthe1−1000Rydbergionizingluminosity,n
istheelectrondensityandRisthedistanceoftheionizingsourcefromthe
absorbingclouds. 2http://darts.jaxa.jp/astro/suzaku/
TheSuzakuviewofhighlyionizedoutflowsinAGN 3
criteria introduced by Winkler (1992). Observations of non-AGN
which were matched by virtue of their having a similar position
toaknownAGNonthesky,suchasthoseofextragalacticultra-
luminousX-raysources(ULXs;Feng&Soria2011)orX-raybright
supernovae,weresystematicallyexcluded.Onlythoseobservations
with exposures long enough to ensure that the net source counts
between2and10keVinthesourcerest-frameexceeded∼15000
wereretained(typicalexposureswere(cid:2)50ks)suchthatanarrow
(i.e.EW=30eV)absorptionfeaturewasdetectableat95percent
fromMonteCarlosimulationsatsourcerest-frameenergiesofup
to8–9keV(seeSection4.4).Inthecaseofthehighred-shiftquasar
APM08279+5255,whichshowsevidenceforabsorptionlinesat
rest-frameenergiesofE>10keV(e.g.Chartasetal.2009;Saez,
Chartas&Brandt2009;Saez&Chartas2011),themeasureofnet
sourcecountswasinsteadtakenfortheentireX-rayimagingspec-
trometer (XIS) bandpass (i.e. 0.6–10 keV in the observer frame)
Figure1. Histogramshowingthedistributionofsourcesincludedinthis D
becausetheFeKfeaturesareshiftedtolowerenergiesduetothe work. The high red-shift QSO APM 08279+5255 (z = 3.91) has been ow
highred-shiftoftheAGN. omittedforscalingpurposes. nlo
a
Ashighlyionizedoutflowsarethoughttooriginateatrelatively d
e
d
sTmomalbledsiisteatnacle.s20fr1o1ma,t2h0e1c2e,nhterraelanftuecrleTu1s1(aen.gd.TG1o2f,forersdpeetctailv.e2ly0)1,1i;t from
isimportantthattheprimarycontinuumemissionfromthecentral http
nucleus,ratherthanthatwhichisreprocessed/scatteredbycircum- ://m
nuclear material out of line of sight, is directly observed so that n
suchoutflowscanbedetected.TothisendweexcludeallType2 ras
.o
sourcestomakesurethatallsourceswereopticallythintoX-rays x
fo
below 10 keV. Therefore only those sources with a Type 1.0–1.9 rd
jo
orientation to the line of sight, as per the classifications listed on u
rn
the NASA/IPAC Extragalactic Database (hereafter NED), in the a
ls
VERONCATcatalogueitselfandthroughliterarysourceswerein- .o
rg
cluded. Note that we conservatively include the radio-quiet AGN a/
ESO 103-G035 (z = 0.01329) which, despite being classified as t N
A
Type2.0intheVERONCATandonNED,isoftenregardedasa S
A
Type1.9Seyfertintheliterature(e.g.Warwick,Pounds&Turner G
1988)byvirtueofthepresenceofamoderatelybroadHαlineinits od
d
opticalspectrum(Phillipsetal.1979).Observationdetailsforall Figure2. Histogramshowingthelogarithmofthetotalfront-illuminated ard
sourcesincludedintheheterogeneouslyselectedsamplearelisted XIS2–10keVcountsinallfittedspectra.Instackedspectra(seeTableA1) S
p
inAppendixAintheonlinesupportinginformation.Thereare99 thetotalco-addedcountsareconsideredhere,ratherthanthecountsineach ac
observations of 51 AGN spanning a wide range of spectral types individualsequence. e F
andradio-properties.AsshowninTable1thesampleisdominated ligh
bylow–moderateinclinationSeyfert1.0–1.5galaxies(28/51;34/51 0.1040), PKS 0558−504 (z = 0.1372) and PBC J0839.7−1214 t C
ifNarrowLineSeyfert1sareincluded)andcontainscomparatively (z=0.198).ThegravitationallylensedquasarAPM08279+5545 tr o
n
fewhigh-inclination(Type1.8–1.9)Seyferts(6/51).Therearesix is by far the most distant object in the sample with a red-shift A
radio-loudsourcesinthesample,includingallfiveoftheBLRGs tohfezfi=tted3.9sp1e.cAtrsasshpoawnntwino oFridge.r2s othfemtoatganlit2u–d1e0bkuetVarecoaupnptsrofxoir- pril 5
includedintheT10Boutflowcasestudy,andfiveQSOs.Thedistri- , 2
mately normally distributed about the peak and mean number of 0
butionsofsourcered-shiftandtotal2–10keVcounts(fortheXIS 1
105counts. 3
front-illuminateddetector)areshowninFigs1and2,respectively.
TheAGNarepredominantlylocal,with∼90percentofthesam-
plebeinglocatedatared-shiftofz(cid:3)0.1,butalsoincludesmore
3 DATA REDUCTION
distantobjectssuchasPDS456(z=0.1840),1H0419−577(z=
3.1 XISreduction
Table1. Sourceclassifications.
TherearefourXISCCDcamerasaboardSuzakuwhichcoverthe
energy range of 0.3–12.0 keV. The XIS 0, XIS 2 and XIS 3 are
Sourceclassification Number
front-illuminated,whiletheXIS1isback-illuminatedandprovides
Sy1.0–1.2 17 superiorsensitivitybelow∼1keVbutalowereffectiveareaanda
Sy1.5 11 higherbackgroundatharderX-rayenergies.TheXIS2suffereda
Sy1.8–1.9 6 chargeleakin2006November3 andisthereforeonlyavailablein
NLSy1 6
observationstakenbeforethisdate.Allspectrawerereducedusing
BLRG 6
QSO 5
Total 51
3http://heasarc.gsfc.nasa.gov/docs/suzaku/news/xis2.html
4 J.Goffordetal.
v6.11oftheHEASoft4 suitefollowingtheprocessoutlinedinthe fitstatistic.HardX-rayfaintand/orhighbackgroundobservations
SuzakuABCDataReductionGuide.5 Eventswereselectedusing wheresourcecountrateswere<4percentofthePINtotalwerenot
ASCAX-raygrades0,2,3,4and6,adoptingthestandardscreening consideredinouranalysis.OnlyAPM08279+5255andPDS456,
criteriasuchthatdatawereexcludediftaken:(1)within436sof amounting to a total of five observations, meet this criterion (see
passagethroughtheSouthAtlanticAnomaly(SAA),(2)withinan TableA1).AswiththeXISdata,thefinalPINexposuresandthe
Earth elevation angle (ELV) <5◦ and/or (3) with Earth day-time totalbackground-subtractedrest-frame15–50keVcountsarelisted
elevation angles <20◦. Hot and flickering pixels were removed inTableA1.
fromtheXISimagesusingtheCLEANSISscript.Sourcespectrawere
extractedfromwithincircularregionsofradius1.5≤r<3.0arcmin
4 ANALYSIS
to ensure good coverage of the source events, while background
spectra were typically extracted from offset circles of the same
4.1 Spectralfitting
radiuswithcaretakentoavoidthechipcornerscontainingtheFe55
calibrationsources.Forintrinsicallyfaintsourcesthebackground Adetailedbroad-bandspectralanalysisofallsourceswasconducted
spectrawereextractedfromcircleslargerthanthoseofthesource usingversion12.6.0qoftheXSPECspectralfittingpackage.Allspec-
andtheratioofsource/backgroundareawasaccountedforwithan tralmodelsaremodifiedbytheappropriatecolumndensityofGalac-
appropriatebackgroundscalingfactor.Redistributionmatricesand ticabsorptionusingvaluestakenfromtheLeiden/Argentine/Bonn D
ancillaryresponsefilesforeachobservationweregeneratedusing SurveyofGalacticHI(Kalberlaetal.2005)whichwereobtained ow
n
thetasksXISRMFGENandXISSIMARFGEN,respectively. fromtheon-lineversionoftheNH FTOOL.6 ThevaluesofGalactic loa
Wherepossiblespectraobtainedfromthefront-illuminatedXIS absorptionforeachsourcearelistedinTableA1.XIS-FIdatawere de
d
detectorswerecombinedintoasinglesourcespectrum(hereafter typicallyconsideredbetween0.6and10.0keV,whileXIS-BIwere fro
XIS-FI)usingMATHPHAinordertomaximizesignal-to-noiseratio only included between 0.6 and 5.0 keV due todecreasing S/Nin m
(S/N)intheFeKband.Mostoftheobservationsinthesamplehave theFeKbandwhichcouldhamperabsorptionlinedetection.All http
dataforatleasttheXIS0andXIS3withafurther22alsohaving XISspectrawereexcludedbetween1.6and2.1keVduetouncer- ://m
datafortheXIS2(seeTableA1).ForSWIFTJ2127.4+5654(OB- taintiesincalibrationassociatedwiththeSiKdetectoredge.Where n
ra
SID702122010)onlydataforthefront-illuminatedXIS3camera available,PINdatawereincludedtocoveratleastthe15–40keV s.o
areavailablebecausetheXIS0wasnotoperationalduringtheob- energyrange. xfo
servation.Spectrafortheback-illuminatedXIS1(hereafterXIS-BI) A constant multiplicative factor was included in all models to rd
jo
werereducedusingthesameprocessasoutlinedaboveandwere accountfortheXIS/PINcross-normalizationwhosevaluedepends urn
analysedsimultaneouslyasaseparateinputspectrum.AllXISspec- not only on the nominal pointing of the observation, but also the als
traweregroupedtohaveaminimumof50countsperenergybin versionoftheSuzakupipelinewithwhichthedatahavebeenpro- .org
toenabletheuseoftheχ2 fitstatistic.NetXISexposuresandthe cessed.ThecurrentXIS/PINratiossuitableforversion2processed a/
total background-subtracted 2–10 keV count rates (in the source dataare1.16(1.18)fortheXIS(HXD)nominalpointingpositions.7 t N
A
rest-frame),forboththeco-addedXIS-FIandtheXIS-BIdetectors, However,thecross-normalizationwasupto∼5–6percentlowerfor S
A
arelistedinTableA1. dataprocessedwithversion1ofthepipeline,correspondingtoan G
o
XIS/PIN ratio of 1.09(1.13)7 in the XIS (PIN) nominal pointing d
d
a
positions.Whilethedifferenceisonlysmalltheadditionaluncer- rd
3.2 HXD/PINreduction taatinEty>ca1n0hkaveVe,apcaorntisciudlearralbyleinefhfeacrdtoXn-trhaeycbornigtihntusuomurpcaersamweittheras Space
Spectra from the Hard X-ray Detector (HXD) Positive Intrinsic high PIN count rate where the model can become driven by the Flig
Negative(PIN)siliconediodeswerealsoreducedusingthemethod hardX-rayband.Toaccountforanysystematiceffectsassociated h
t C
oacuctloirndeidnginttohethSeuzsackrueeDnaintagRcerdituecritaiondeGscuriidbeedanpdr,eavgiaoiuns,lpy.roAcessstehde wstaitnhttphaerainmsetrtuemriennetaalcchromsos-dcealltiobrvaatiroyn±w5eptehrecreefnotraebaolulotwthtehveacluoens- tr on
A
HXD/PINisacollimatingratherthananimaginginstrument,the suggestedbytheSuzakuteamtotakeintoaccountanysystematic p
contributionofboththeinstrumentalnon-X-raybackground(NXB) errors. ril 5
andthecosmicX-raybackground(CXB)needstobeindependently Thereare20AGNinthesamplewhichhavetwoormoreSuzaku , 2
0
accounted for when estimating the total background. The NXB observations. In APM 08279+5255, IC 4329A, MCG -6-30-15, 13
wasgeneratedusingtheappropriateresponseandtunedeventfiles Mrk 841, NGC 5506, NGC 5548 and PKS 0558−504 the differ-
(backgroundmodelD)foreachobservation.Commongoodtime ent observations are similar in spectral shape which allows them
intervals (GTIs) in the event and background files were selected tobeco-addedusingtheappropriaterelativeweightingfactorsto
usingMGTIMEandspectralfileswereextractedusingXSELECT.PIN takeintoaccountdifferencesinindividualexposures,withthere-
detectordead-timewasaccountedforusingtheHXDDTCORtaskand sultant time-averaged spectra for these sources being used in all
theNXBbackgroundexposurewasincreasedbytentimestoreduce subsequentanalyses.1H0419−577andNGC2992bothhadob-
theeffectsofphotonnoise.TheCXBcontributionwassimulated servationswhichweretakenindifferentSuzakunominalpointing
usingtheformofBoldt(1987),combinedwiththeNXBtoforma positionswhichcouldinfluenceco-adding.However,effectivearea
totalbackgroundspectrumusingMATHPHA,whichwassubsequently wasalwaysconsistenttowithin±10percentandsothespectrawere
subtractedfromthesourcespectrumwithinXSPEC. stillco-addedusingthemeanoftheresponsefiles.Anyadditional
Allbackground-subtractedPINspectrawerebinnedtoatleastthe systematicuncertaintyintroducedwasadequatelyaccountedforby
3σ levelabovebackground(typically>5σ)toenabletheuseofχ2
6http://heasarc.gsfc.nasa.gov/cgi-bin/Tools/w3nh/w3nh.pl
4http://heasarc.nasa.gov/lheasoft/ 7http://www.astro.isas.jaxa.jp/suzaku/doc/suzakumemo/suzakumemo-
5ftp://legacy.gsfc.nasa.gov/suzaku/doc/suzaku_abc_guide.pdf 2007-11.pdf
TheSuzakuviewofhighlyionizedoutflowsinAGN 5
thevariableXIS/PINcross-normalization.In3C120andMrk509, listed in Tables D2 and D3 for single- and multi-epoch spectra,
whichbothshowednotablevariabilitybetweenobservations,spec- respectively.Adescriptionoftheunderlyingmodellingassumptions
tra were jointly fitted depending on the extent of their spectral and associated caveats is presented in Appendix C in the online
variability between epochs. In 3C 120 we followed the analysis supportinginformation.
methodofKataokaetal.(2007)andT10Bbyco-addingOBSIDs
700001020, 70001030 and 70001040, which are all of a similar
spectralshapeandfluxlevel,andjointlyfittedthemwithOBSID 4.2.1 WarmabsorptionI:fullcovering
700001010 which has a more prominent underlying soft-excess.
Dependingonthepropertiesoftheinterveningmaterial(suchasits
InMrk509,whichiswellknownforhavingastrongsoft-excess
ionizationstateandcolumndensity)absorptionbycircumnuclear
(Mehdipouretal.2011),OBSID701093010,thestackedOBSIDs
materialcanaddsignificantspectralcurvaturetotheobservedX-ray
701093020,701093030,701093040andOBSID705025010were
spectrumandcanthereforehaveadirecteffectonthecontinuum
fittedsimultaneouslytoaccountfortheobservedvariabilityinthe
andlineparametersmeasuredinbroad-bandmodels.Inthiswork
softX-rayband. wemodelwarmabsorptioncomponentsusingasuiteofxstar(v.
The remaining nine sources with more than one observation
2.2.1bc)tableswhichareallgeneratedassuminginputvalueswhich
(3C111,Fairall9,Mrk766,NGC1365,NGC3227,NGC3516, are ‘typical’ for local Seyfert galaxies8 (e.g. T11). The resultant
NGC3783,NGC4051andPDS456)showedstrongspectralvari- xstar tables cover a wide range of parameter space in terms of D
ability in both the shape of the spectrum and/or drastic changes column densities [1018 < log(N /cm−2) ≤ 1024], and ionization ow
in flux state which made co-adding impractical. In these sources parameter[−3<log(ξ/ergcmsH−1)≤6]whichmakesthemwell nlo
a
the available spectra were fitted simultaneously and a model was d
suitedforaccountingforallmannersofwarmabsorption. e
d
cfeownsatrdudcitteiodnatolfdreeescpraibraemtheteerosbasserpvoesdsibsplee.cItnraNl GvaCria1b3i6li5ty,OwBitShIDass whFeurell-nceocveesrsinargywtoaramchaiebvseoraptgioonodzofintetsoathreeisnocfltuXde-drayinbmanodd;eilns from
702047010and705031010aredominatedbyverydeepFeKab- somecasesmorethanoneabsorptionzoneisneeded.Inthesecases http
sorption lines. These lines are not present in OBSID 705031020, thecolumndensityandionizationparameterofeachzoneareal- ://m
pdoomssiinbalyteddusetateto(steheeMsaoiuorlcineodertoaplp.in2g010intfooradeqtauialssio-sfctahtetervianrgi-- lwohwiecdhtcoovnasirsytsinodfempeunldtiepnletlylaaynedrsreopfrgesaesn.tAatnthabeseonrpertgioynrgeesoomluetitoryn nras.o
ability patterns in this source). For simplicity we therefore only x
of the XIS CCDs the bound–bound absorption lines required to fo
simultaneously fitted OBSID 702047010 and OBSID 705031010 constraintheoutflowvelocitiesofindividualsoftX-rayabsorption rdjo
inTNhGeCχ1236m5i,naimndizfiatttieodnOteBcShnIDiqu7e05i0s3u1s0e2d0tsherpoaurgahteoluyt. this work, componentsareunresolvedandallabsorptionzonesaretherefore urna
fittedasstationaryinthesourcerest-frame(i.e.fixedoutflowve- ls
w((cid:7)itχh2al=ls2ta.7ti1stifcoarloenrreoprsarqaumoetetedrtoofthinete9r0epste)r.cWenhtecreontfihedesntacteislteivceall sloocfittiXes-roayfvaobusto=rbe0rktmo vsa−r1y).aAlwllaoywsinhgasthaenoeugtlfligoiwbleveelfofceicttyoonftthhee a.org/
significanceofcomponentsisquotedintermsofa(cid:7)χ2 valuethe reportedFeKabsorptionlineparameters. t N
A
componentinquestionhasbeenremovedfromthemodelandthe S
A
datarefittedtoensurethattheorderinwhichcomponentsareadded G
tothemodelhasnoinfluenceonthederivedstatistics.Whenrefer- 4.2.2 WarmabsorptionII:partialcovering od
d
orifntghteofistt,awtishtiilcealacnheagnagteivseto(cid:7)aχfi2tianpdoicsaittievsea(cid:7)sχta2tidsetincoatleismapwroovresmeneinntg. Wealsoconsiderthepossibilitythatthesightlinetoasourceispar- ard S
Positiveoutflowvelocitiescorrespondtoanetblue-shiftrelativeto tiallycovered.Inthisabsorptiongeometryafractionfcov<1ofthe pac
thesystematicofthehostgalaxy,whileanegativevelocityindicates sourcefluxisabsorbedwiththeremaining1−fcovleakingthrough e F
anetred-shift. theabsorptionlayer.Forsimplicityweaccountforpartial-covering ligh
absorptionlayersusingacustomizedversionofthezxipcfmodel9 t C
whichmodelsthepartial-coveringabsorptionbypartiallyionized tr o
4.2 Modelconstruction gas(seeReevesetal.2008a)withoutneedingtousecomplicated n A
All spectra were first fitted with a power law modified solely nraemsteetderpsoiwneorulrawcusstaonmdizxesdtatarblteabmleosd.eAlsarienczoxluimpcnfdethnesitfyre(eNpa)-, pril 5
by Galactic absorption. Additional components were added to ionization parameter (logξ), covering fraction (f ) and red-shHift , 20
the model and retained provided their significance exceeded cov 1
the>99percentconfidencelevelbytheF-test.Anyemissionlines relativetotheobserver(z).Themodelisbasedonthesametables 3
inthesoftX-raybandwerefittedwithnarrowGaussians(σ∼5eV). asdiscussedinSection4.2.1andthereforehasaslightlylowertur-
bulentvelocitythanzxipcf,atv =100kms−1,butcoversthe
Insourceswithmultiplespectraweinitiallyfoundabroad-bandfit turb
same parameter space in terms of column density and ionization
to the observation with the highest flux; later observations were
parameter.
thenaddedsequentiallyandthecontinuum/absorptionparameters
Partial-covering absorption can have a strong effect on the ob-
wereallowedtotovaryindependentlyuntilasimultaneousfittoall
servedcontinuumwithmoderatecolumndensitiesofmaterial(N ∼
spectrahadbeenachievedusingasfewfreeparametersaspossible. H
1023 cm−2)addingconsiderablespectralcurvatureatE<10keV
Once a statistically acceptable fit to the broad-band spectrum of
(Reevesetal.2004;Risalitietal.2005;Braitoetal.2011;Turner
eachsourcehadbeenfound,wefittedanynecessaryemissioncom-
ponentsandthenperformedasystematicandmethodicalsearchfor
FeKabsorptionlinesbetween5and10keVusingenergy–intensity
8Absorptiongridsaredescribedbyanilluminatingphotonindexof(cid:8) =
planecontourplots(Section4.3)anddetailedMonteCarlosimula- 2.1,agasdensityofn=1010cm−3,amicro-turbulentvelocityofvturb=
tions(Section4.4). 100kms−1andanintegratedmodelluminosityofL=1044ergs−1between
Themodellingapproachforindividualspectralcomponentsare 1and1000Rydbergs.
outlined below, with the continuum parameters for each source 9Thestandardzxipcfusesaspecificgridwiththefollowingparameters:
being noted in Table D1 and those for the warm absorber being (cid:8)=2.2,n=1010cm−3,vturb=200kms−1,L=1044ergs−1.
6 J.Goffordetal.
etal.2011).Bound-freetransitionsinsimilarcolumndensityma- 4.2.4 Lowlyionizedreflection
terialcanalsofitbroadresidualemissionprofilesintheFeKband
Coldreflectionfromlargecolumndensitiesofneutralorlowlyion-
(Inoue&Matsumoto2003;Miller,Turner&Reeves2008,2009;
izedmaterialoutsideofthesightlinecanhaveastronginfluence
Tatumetal.2012),andpartialcoveringbyCompton-thickmaterial
(N (cid:2)1024cm−2)canreducetheobservedemissionbelow10keV ontheobservedX-rayspectrum.Thestrongestobservationalchar-
H acteristicsofsuchreflectionincludetheCompton-reflectionhump
withthetrueintrinsiccontinuumonlybecomingapparentathigher
at∼30−40keVandthealmostubiquitousFeKα andFeKβ flu-
energies as a ‘hard excess’ of emission relative to that expected
orescencelinesat∼6.4and∼7.06keV(Nandraetal.2007;Shu,
fromstandardreflectionmodels(Reevesetal.2009;Risalitietal.
Yaqoob&Wang2010),respectively.Comptondown-scatteringof
2009;Turneretal.2009;Tatumetal.2013).
both Kα line photons and high energy continuum emission also
We include partially-covering absorbers in our models if and
gives rise to a ‘Compton shoulder’ at ∼6.2 keV (e.g. Matt 2002;
whentheyarerequiredbythedataattheP ≥99percentconfidence
F Yaqoob & Murphy 2011) and resonant line emission in the soft
levelandasatisfactoryfittothedatacouldnotbeachievedusing
X-ray band (e.g. Ross & Fabian 2005; Garc´ıa & Kallman 2010)
solely fully-covering absorption; several sources appear to need
whichcanfurthercomplicatetheemergentspectrum.
multiple partially-covering absorption zones which suggests the
Naturally, owing to the important effect it can have on the
presence of a clumpy stratified absorber along the line of sight.
observed X-ray spectrum there are numerous models available
Again, all absorber parameters are listed in Tables D2 and D3 in
for modelling the reflection component (e.g. pexrav/pexriv, D
AinpspoemndeicxirDcuminsttahneceosntlhineenesuedppoofratinhgighincfoorlummatniodne.nWsiteypnaortteiatlhlya-t Mreafgldizoianrxz, R&osZsd&ziaFrasbkiian1929050;5;pxeixlmlovne,r,N10anGdarrac´ıaet&alK.al2l0m0a7n; ownloa
coveringcomponentcanbecontingentonthemeanswithwhichthe d
2010;MYTorus,11Murphy&Yaqoob2009).Inthisworkweusea ed
udnegdeenrleyriancgierse.flHecotwioenvecro,maspowneendtisicsumssodinelAlepdpleenaddiixngCt,orseogmaredlmesosdoefl combinationofreflionxandpexrav,bothofwhicharepublicly from
whetherthehardX-raydataarefittedwithreflectionornot,partial afovraitlhaibsleitatnhdatebxetecnasuisveelryeufsleidoinnxthinetleirtperoaltauteres.tThheeopbrsiemrvaerydrreeaflseocn- http
covering has little measurable effect on the parameters measured tionspectrumfromapre-generatedgridoftablemodelsitissignifi- ://m
foranyhighlyionizedabsorptionlinesystems. cantlyfasteratfittingspectrathan,forexample,pexrav,pexrivor nra
s
pexmon,whichanalyticallycalculatetheComptonreflectionspec- .o
x
trumontheflyateachstepofthefittingprocess,orMYToruswhich fo
rd
4.2.3 Thesoft-excess requiresthemodeltobetailoredforeachindividualsource.Using jo
u
reflionxasourprimarymeansoffittingthereflectionspectrum rn
Relative to the low energy extrapolation of the power-law con- a
ensurestheleasttime-consumingMonteCarlosimulationswhich ls
tinuum in the 2–10 keV band the X-ray spectrum of AGN often .o
&shoPwosunadssm19o8o8th;Pinocrrqeuaesteeitnale.m2i0tt0e4d).flTuhxebtehleorwma∼l1temkepVera(tTuurrenoefr ittshinaiutmucpmoonrwstiadintehtroewudthietnhnethdsiesiamwliunolgrtakwn.eSiotehucsoancldoalrnygs,etwrashianemtnpofilfetttiohnfegoFrbeejfleKecctαstilosiunncechothnaes- at NArg/
this‘soft-excess’suggeststhatitisunlikelytobethedirectemis- reflection fraction, R, reported by pexrav (and pexriv) can be- SA
s(Sioonbofrloemwsakast&andDaorndea2c0cr0e7t;ioDnodniescetwailt.h2o0u1t2a)d.dAitlitoenrnalatrievperoexcpeslasninag- comedegeneratewiththephotonindexoftheprimarypowerlaw, God
withahardeningreflectioncomponentcompensatedforbyasofter d
tionspositthatthesoft-excessmaybeduetoanincreaseinoptical primarycontinuum.Bysimultaneouslyfittingthereflectioncontin- ard
dsietpiothnsaasstoEci(cid:3)ate0d.7wkiethVcwirhcuicmhncuacnleeanrhOanVcIeI–eVitIIhIearntdheFetraLn-ssmheiltltetrdaonr- uum,theFeKαlineandthesoftX-rayresonancelines,reflionx Spac
reflectedfluxalongthesightlinethroughsmearedabsorption(e.g. isabletoovercomethesemodellingdegeneracieswhichleadstoa e F
CDhoenvea2ll0ie0r7)eotrabl.lu2r0re0d6;reDfloecnteio&n(Ne.agy.aCkrsuhminm2y0e0t7a;l.S2o0b0o6l;ewBrseknan&e- ctoonthfiedoenbtsecrovnesdtrsapinetctornumth.erceofnltriiobnutxioanlsoofhthasetrheefleacdtdioitniocnoanltainduvuanm- light C
manetal.2011;Nardinietal.2011;Nardini,Fabian&Walton2012) tageofallowingtheionizationstateofthereflector,ξ,tobeafree tr o
effects.Furthermore,insomesources(e.g.Mrk766,Milleretal. parameterwhichenablesittomodelchangesintheFeKαemitted n A
2007;MCG-6-30-15,Milleretal.2008)the‘excess’couldsimply flizuaxtioanndstFaeteK.W-sehesltlreesdsg,ehporwoefivleera,stshoactieaqteudivwaliethntthreesruelfltseacrtoerfsoiuonnd- pril 5
bopeaacpitryodaruocutnodfc∼o1m–p2lekxeVab.sorptionandjustbethemanifestationof forthedetectedFeKabsorbersifpexmonisusedinstead,butwith , 201
theresultantMonteCarlosimulationstakingsignificantlylongerto 3
Regardless of the true physical origin we take a purely phe-
completewhicheffectivelyprohibitsitsuniformusethroughoutthe
nomenologicalapproachwhenfittingthesoft-excessinthiswork,
sample.
andpredominantlyusethebbodymodelwhichrepresentstheemis-
Weinitiallyfittedallsourceswithpexravtodeterminethepa-
sionfromaconstanttemperatureblackbody.Whilenotnecessarily
rameters of the Fe Kα and Fe Kβ lines. pexrav was then re-
physicallymotivated,modellingthesoft-excessinthismannerof-
placed with reflionx, and a systematic search for additional
fersasimpleparametrizationofany‘excess’softX-rayemission
atomic features in the Fe K band was conducted. A total of 11
whichissufficienttogetagoodhandleontheunderlyingcontin-
sources have best-fitting reflector Fe abundances which are non-
uum parameters. For completeness we investigate the effects that
solar, with 4 requiring a slight over-abundance (MCG+8-11-11,
otherwaysofmodellingthesoft-excesscanhaveonanyFeK-band
NCG4593,NCG7213,NCG7469)and7withanunder-abundance
absorptionlinesinAppendixC.Roughlyhalfofthesourcesinthe
(4C +74.26, Fairall 9, IC 4329A, IGR J16185−5928, Mrk 335,
sample (24/51; ∼47percent) show evidence for a soft-excess, of
which 22/24 are fitted with a bbody component. In 3C 120 and
Mrk 509 the soft-excess is very broad and extends beyond that 10The xillver reflection model is not currently available in the public
whichcanbefittedwithasimpleblackbody.Inthesesourceswe domainandisthereforenotconsideredforuseinthiswork.
insteadfittheexcesswithasecondpowerlawwithasofterphoton 11The MYTorus model and documentation are publicly available at:
index. www.mytorus.com
TheSuzakuviewofhighlyionizedoutflowsinAGN 7
Mrk359,Mrk841).Theseabundancesaremostlikelyabyprod- diskline12 dependingontheasymmetryoftheobservedprofile,
uctofreflionxassumingaface-onreflectiongeometry,andisa andasecondintermediatecontourplotwasgeneratedtodetermine
caveatwhichisdiscussedingreaterdetailinAppendixC.PDS456 whether any further components were needed by the model. As
andAPM08279+5255arenotfittedwithareflectioncomponent before, all other model parameters were allowed to vary freely
becausetheylacksufficientcountsintheHXD/PIN. during this process. If there was no evidence for a broad profile
wedidnotgenerateanadditionalcontourplotandinsteadmoved
directlyontothenextstep;
(iv) wherenarrowemissionprofilesweredetectedwitharesolved
4.3 SearchingforFeKabsorption confidencecontourof>99percenttheywerefittedwithunresolved
(σ =10eVfixed)Gaussianprofilesprovidedtheywererequired
Onceastatisticallyacceptablefittothebroad-bandcontinuumhad
bythedataatP >99percent(correspondingto(cid:7)χ2 >9.21for
been found, i.e. including all necessary absorption regions, soft F
twoparametersofinterest);
X-ray emission lines and continuum components, we performed
(v) onceallemissionprofileshadbeenaccountedforweagain
a thorough search for additional spectral features between 5 and
checkedforthepresenceofanyblue-shiftedFeKabsorptionlines
10 keV. The method consists of inspecting the |(cid:7)χ2| deviations
atE>6.7keV.Ifnoabsorptionlineswerepresentweendedthe
fromthebest-fittingcontinuummodelusinginvertedcontourplots
of the energy–intensity plane in the Fe K band. The method of search at this step, reported the best-fitting continuum and Fe K D
emissionlineparametersintherelevanttablesofAppendixD,and ow
calculatingthecontourplotswasadaptedfromthemethodoutlined n
inT10A,andwascarriedoutasfollows: movedontothenextobservationinthesample; loa
(vi) otherwise, where absorption troughs were clearly detected de
(i) anunresolved(σ =10eV)Gaussianwassteppedacrossthe wliniteh(s)aucsoinngfidinenvecretecdonGtaouusrsioafns>w9i9thpeσr-cwenidtthwieniptiaarlalymefitxriezdedattehie- d from
entire5–10keVenergybandofthebaselinecontinuummodelin
25eVintervals,withnormalizationallowedtoadoptbothpositive ther 10, 30 or 100 eV depending on which provided the greatest http
andnegativevaluestoprobeforspectrallinesinbothemissionand improvementto(cid:7)χ2.Notethatwhileinitiallyfixed,thelinewidths ://m
absorption.Alloftheotherspectralcomponents wereallowed to wereallowedtovarywhereappropriateleadingtofoursourceswith nra
befree; resolvedabsorptionprofiles.Thekeyparametersofalldetectedab- s.o
(ii) after each step the (cid:7)χ2 deviation was recorded generating sorptionlinesarereportedinTable2. xfo
a χ2 distribution of the entire Fe K band relative to the baseline Thisprocesswascarriedoutoneachindividuallyfittedspectrum rdjo
u
continuummodel; in the sample, including those which were included in simulta- rn
cor(diiiin)gctoon(cid:7)fidχe2ncdeevcioantitoonusrsoffo−rt2h.e3g,−rid4.o6f1χ,2−v9a.l2u1e,s−w1e3re.8p2l,o−tte1d8.a4c2- napeopulisedfittos.AInrkF1ig2s03(OaBnSdID4 7w0e20s1h4o0w10e)x,awmhpilcehssohfowthsisevpirdoecnecses als.org
from the baseline model, which correspond to confidence in- for a broad asymmetric emission profile and no absorption lines, at N/
tervals of 68percent, 90percent, 99percent, 99.9percent and andMrk766(OBSID701035020),whichisdominatedbyFeXXV A
9to9.a99(cid:7)pχer2c=ent+, r0e.s5pewcotirvseelyfi.tAiscaolnsofidpelnoctteedcownhtoicuhr cisorirnetsepnodneddintgo sHheoαwatnhderFeesidXuXaVlIsLwyhαicahbrseomrpatiinoni.nTthheeFtoepKpbaannedlswohfebnoathllfiatgoumreics SA Go
denoteanapproximatelevelforthecontinuum. lines have been removed from the best-fitting continuum model dda
Theenergy–intensitycontourplotsproducedwiththismethodpro- athnedptrheesernecfleecotfiotnheconmeuptroanleFnet iKsαfi/tFteedKwβitflhupoerexsrcaenvcetolihniegsh.liTghhet rd Spa
vsoidrpetiaopnocwoemrfpuolnmenetasnpsroefsesnetarinchtihnegFfoerKadbdaintidonwahlielemaislssoionviosuraalbly- cwohnetnoutrhepFloetsKsαhoawndtFheeKsiβgnliifinceasnhcaevseobfeethnefitrteemdawiniitnhgrerefslidiuoanlxs ce Flig
assessing their energy, intensity and rough statistical requirement h
and a narrow Gaussian line. The continuous outer contour cor- t C
relTathiveeretoarteheaunnudmebrleyrinogfactoonmtiincufuematumreosdeble.tween6.0and8.0keV responds to the (cid:7)χ2 = +0.5 residual as mentioned previously. tr on
Fromoutertoinnertheclosedsignificancecontourscorresponding A
wfehatiuchrecsainnccloumdepliiocnaitzeetdheemdeitsesciotinonlinoefsabfrsoomrptFioenXXliVneansydsFteemXsX.VSIuecxh- 9to0(cid:7)peχrc2einmt)p,r−ov9e.2m1e(nPts=of9−92p.e3rc(PenFt)=,−6183p.8e2rc(ePnt)=, −994..96p1e(rPcFen=t) pril 5
epdegcteecdoamtp∼le6x.6a3t−∼67..71kaenVd,∼a6n.d97ankyebVr,oraedspFeecltiinveelpyr,otfihleedFueeKto-sGheelnl- tainnduu−m18m.4o2de(lPaFre=s9h9oF.w99npienrrceedn,t)grreeleant,ivbelutoe,thcyeFabnesatn-dfittminaggecnotna-, , 2013
eralRelativity(GR)orscatteringeffects.Itisimportanttoaccount
respectively.
fortheseemissionresiduapriortosearchingforabsorptionlines,
Thereareclearresidualprofilespresentinbothsources,particu-
particularly in sources which show evidence for a broad residual
larlyArk120wherethepositiveasymmetricprofileandadditional
asthebroadnessoftheprofilecaneffectivelymaskthepresenceof
FeXXVIemissionareapparentinthemiddleandbottompanelsof
low-velocityabsorptionsystemsintherawdata.Foragivencontin-
Fig.3,respectively.ThetwoabsorptionprofilesinMrk766–which
uummodelwesearchedforhighlyionizedabsorptionlinesinthe
have previously been identified as Fe XXV Heα and Fe XXVI Lyα,
FeKbandusingthefollowingsteps:
respectively,byMilleretal.(2007)–arestatisticallydistinguish-
able at >99.99percent confidence and are self-consistently fitted
(i) wefirstgeneratedanenergy–intensitycontourplotusingthe
withasinglehighlyionizedregionofphotoionizedabsorption(see
methodoutlinedabove;
Section4.6).Energy–intensitycontourplotsforallfittedspectrain
(ii) wetheninspectedthecontourplottodeterminewhetherthere
wereanyintenseionizedemissionandabsorptionlinespresentin
thedatawithconfidencecontoursof>99percent; 12Forsimplicity,thedisklinewasfittedwithanassumedrest-frameenergy
(iii) wheretherewasevidenceforabroademissionresidualatan ofE=6.4keVandatypicalemissivityprofileofq=−2.5(e.g.Patrick
F-testsignificanceofatleastPF>99percenttheywerefittedwith etal.2011a).Theinneremissionradius(Rin),outerradius(Rout)anddisc
eitherabroadenedGaussian(withσ-widthafreeparameter)ora inclination(i)wereleftfreetovary.
8 J.Goffordetal.
Table2. GaussianparametersfordetectedFeKbandabsorptionlines.Notes:(1)sourcename;(2)SuzakuobservationID;(3)absorptionline
identification;(4)measuredlineenergyinthesourcerest-frame,inunitsofkeV;(5)measuredlineenergywidth,inunitsofeV.Unresolvedlines
werefittedwithwidthsfixedat10,30or100eVdependinguponwhichyieldedthebeststatisticalimprovementtothefit;(6)lineintensity,in
unitsof×10−6photonscm−2s−1;(7)lineEW,inunitsofeV;(8)changeinfitstatistic(anddegreesoffreedom)whenthelineisremovedfrom
thebest-fittingmodel;(9)linesignificanceaccordingtotheF-test,inpercent;(10)MonteCarlosignificanceofindividuallines,inpercent;
(11)MonteCarlosignificanceofobservingapairoflineswithenergyseparationcorrespondingtoaFeXXV–XXVIpair(seethetextfordetails),
inpercent.AbsorptioncomplexesdetectedatPMC≥99percentconfidencearelistedinbold.
Source OBSID LineID Energy σ-width Intensity EW (cid:7)χ2/(cid:7)ν PF PM1C PM2C
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)
3C111 703034010 Lyα 7.24+−00..0044 10f −5.6+−22..11 −26+−99 16.4/2 >99.99 99.8
705040020 Lyα 7.76+−00..0074 10f −15.2+−55..11 −20+−1100 11.1/2 99.60 97.8
3C390.3 701060010 Lyα 8.08+−00..0065 10f −5.6+−22..66 −21+−1100 12.1/2 >99.99 98.7
4+74.26 702057010 Lyα 8.38+−00..0057 10f −7.2+−33..44 −29+−1144 12.4/2 99.80 96.6
APM08279+5255 stacked Heα–Lyα(1) 7.76+−00..1111 100f −6.9+−22..53 −24+−88 23.8/2 >99.99 99.7
Heα–Lyα(2) 10.97+−00..1166 100f −4.4+−11..98 −30+−1155 18.4/2 >99.99 97.3 D
CBS126 705042010 Lyα 7.04+−00..0045 30f −3.3+−11..00 −77+−2222 27.5/2 >99.99 >99.9 ow
EMMMSRrCOkG22127-056931--3-G1070-18355 s777t000ac434k000e335d115[000a111ll000] FeHLLLLyyy–eααααHeα 78767.....0827558625+−+−+−+−+−0000000000..........00000011005521222266 110911143000+−+−fff65861542 −−−−−1142752.....79815+−+−+−+−+−4444111111..........8111222200 −−−−−4371102384+−+−+−+−+−1111333333440000 3822151565.....06791/////32232 >>>>9999999999.....9999959999 >>>9999999999.....99961 >99.9 httpnloaded from
Mrk766 701035010 Heα 7.11+−00..0077 10f −2.8+−11..66 −27+−1155 7.0/2 96.27 71.0 99.8 ://m
Lyα 7.42+−00..0066 10f −3.9+−11..66 −40+−1177 15.3/2 99.92 98.4 nra
701035020 Heα 6.80+−00..0022 10f −7.7+−11..88 −60+−1144 50.0/2 >99.99 >99.9 >99.9 s.ox
NGC1365 702047010 HLyeαα 76..1727+−+−0000....00004411 6150+−f88 −−295..90+−+−1111....6699 −−14546+−+−117788 111283..89//23 >>9999..9999 >9999..89 >99.9 fordjou
Lyα 6.97+−00..0033 65(cid:4) −8.7+−11..77 −69+−1133 77.0/3 >99.99 >99.9 rna
Heβ 7.94+−00..0011 65(cid:4) −26.1+−11..55 −164+−1100 964.5/3 >99.99 >99.9 ls.o
704031010 HLyeβα 86..3781+−+−0000....00003322 3605(cid:4)f −−1106..61+−+−1122....8844 −−8677+−+−11115500 19344..39//32 >>9999..9999 >>9999..99 >99.9 at Nrg/
Lyα 7.00+−00..0022 30(cid:4) −13.4+−22..00 −85+−1144 90.7/2 >99.99 >99.9 AS
Heβ 7.87+−00..0088 30(cid:4) −4.7+−22..55 −34+−2200 7.2/2 96.77 – A G
NGC3227 703022010 HLyeβα 86..3679+−+−0000....11001144 1300(cid:4)f −−59..39+−+−2233....7777 −−4251+−+−227744 187..55//22 9998..9293 >99.–9 >99.9 oddard
Lyα 6.95+−00..0033 10f −15.5+−33..77 −38+−99 42.4/2 >99.99 >99.9 Sp
NNNGGGCCC334570185631 777177000000343010000000262330232134000000315111000000 HHHHHHLLLyyyeeeeeeααααααααα 777666666.........000777767054616497+−+−+−+−+−+−+−+−+−000000000000000000..................000000000000000000345577332222442244 111111111000000000fffffffff −−−−−−−−−111104865962.........000568102+−+−+−+−+−+−+−+−+−223333333322111111..................882011556688667700 −−−−−−−−−222142212214915060+−+−+−+−+−+−+−+−+−1111999899556656351100 1146635996215606.........202672739/////////222222232 >>>>>999999999999999989.........999999763499999449 >>>>>999999998999999619.........999998284 >>>>99999999....9999 ace Flight Ctr on April 5, 2013
Lyα 7.08+−00..0033 10f −3.3+−11..11 −38+−1133 22.7/2 >99.99 >99.9
703023010 Heα 6.82+−00..0033 10f −4.8+−11..33 −22+−66 26.4/2 >99.99 >99.9 >99.9
Lyα 7.11+−00..0022 10f −6.4+−11..33 −33+−77 57.5/2 >99.99 >99.9
NGC4151 701034010 Lyα 7.17+−00..0044 92+−5411 −15.9+−44..73 −28+−88 43.7/3 >99.99 >99.9
NGC4395 702001010 Heα 6.63+−00..0075 10f −2.2+−11..11 −35+−1199 10.4/2 >99.99 74.5 >99.9
Lyα 6.91+−00..0066 10f −2.9+1.11.1 −55+−2200 18.3/2 >99.99 86.8
NGC5506 stacked[all] Lyα 9.23+−00..0066 10f −11.1+−44..77 −16+−55 16.2/2 >99.99 99.8
PDS456 701056010 Heα–Lyα(1) 9.07+−00..0066 100f −2.5+−00..88 −108+−3355 29.5/2 >99.99 >99.9
Heα–Lyα(2) 9.57+−00..0099 100f −2.0+−00..88 −99+−4411 15.7/2 >99.99 99.8
705041010 Heα–Lyα(1) 8.58+−00..0099 100f −2.8+−11..00 −118+−4466 19.5/2 >99.99 96.2
Heα–Lyα(2) 9.03+−00..0099 100f −3.5+−11..11 −169+−5511 78.6/2 >99.99 >99.9
SJ2127.4+5654 702122010 Lyα 9.04+−00..0055 10f −10.0+−44..77 −60+−2288 11.9/2 99.78 98.9
findicatesthataparameterwasfrozenduringspectralfitting.
(cid:4)indicatesthataparameterwastiedduringspectralfitting.
TheSuzakuviewofhighlyionizedoutflowsinAGN 9
D
o
w
n
lo
a
d
e
d
fro
m
h
ttp
://m
n
ra
s
.o
x
fo
Figure4. Toppanel:asinthecaseofFig.3,butthistimeforMrk766 rd
jo
(OBSID701035020).Bottompanel:asinthecorrespondingpanelofFig.3. u
There are no ionized emission lines required in Mrk 766; however, two rna
highlysignificant(eachrequiredatPF>99.99percent)absorptionprofiles ls.o
aarnedcFleeaXrlXyVdIeLtyeαct,erde.sTpheceteivneelryg,yoouftflthoewsienlginaetsviosucto∼ns6i0st0e0ntkwmitsh−F1e.XXVHeα at Nrg/
A
S
significances.Indeed,ashasbeenpointedoutbynumerousauthors A
G
in the literature (e.g. Protassov et al. 2002; Porquet et al. 2004; o
Figure 3. Top panel: ratio plot showing the residuals remaining in the d
Fe K band of Ark 120 (OBSID 702014010) once all atomic lines have Markowitz,Reeves&Braito2006;T10A)theF-testalonemight dard
beenremovedandreflectionfittedwithpexrav.Middlepanel:confidence notbeanadequatestatisticaltesttodeterminethedetectionsignifi- S
p
contoursshowingdeviationsfromthebest-fittingmodelwhentheFeKα canceofatomiclinesincomplexspectralmodelsasitneithertakes ac
e
and Fe Kβ lines have been fitted with reflionx and a narrow Gaus- into account the number of energy resolution bins over a given F
sian, respectively. The closed significance contours corresponding (from energy range, nor the expected energy of a given atomic line. In lig
h
outertoinner)to(cid:7)χ2 improvementsof−2.3(PF =68percent),−4.61 caseswherethereisnoapriorijustificationforexpectingaspectral t C
(PF=90percent),−9.21(PF=99percent),−13.82(PF=99.9percent) line at a particular energy and the line search is done over what tr o
and −18.42 (PF = 99.99percent) relative to the best-fitting continuum isessentiallyanarbitraryenergyrange,asisoftenthecasewhen n A
modelareshowninred,green,blue,cyanandmagenta,respectively.The p
muaalgiesnstaigcnoifintcoaunrtsainttthheem>i9d9d.l9e9ppaenrecleinndtilceavteelthanatdththeabtraonadaedmdiitsisoinoanlrceosimd-- dsoemalienwghwatiothvesrtprorendgilcyttbhleued-estheicfttieodnapbrosobrapbtiiloitnylainnedsw,thheenFco-tmesptacreadn ril 5, 2
toextensivesimulations.Forthesereasonsallsuspectedabsorption 0
ponentisrequiredinthemodel.Bottompanel:theremainingconfidence 1
lines which have an F-test significance of P > 99percent were 3
contoursoncethebroadprofilehasbeenfitted.Thebroadresiduaareno F
longerdetectedbutanadditionalFeXXVIemissionlineispresentatE∼ followedupwithextensiveMonteCarlosimulationswhichallows
6.97keVwhichissignificantat>99percent.Inallpanelsthedashedverti- theirdetectionsignificancetobeassessedagainstrandomfluctua-
callinesindicatetheexpectedrest-frameenergiesof(fromlefttoright)the tionsandphotonnoiseinthespectrum.
FeKαfluorescenceline,FeXXVHeαandFeXXVILyα,respectively.
4.4 MonteCarlosimulations
thissampleareincludedinFigsB1andB2inAppendixB,inthe
onlinesupportinginformation.Wenotethatthe(cid:7)χ2ofindividual Such Monte Carlo simulations have been used extensively in the
linesandtheircorrespondingsignificancesaccordingtotheF-test literature to overcome the limitations of the F-test (e.g. Porquet
as listed in Table 2 are taken from a direct spectral fitting of the etal.2004;Markowitzetal.2006;Miniutti&Fabian2006;T10A;
lineprofilesthemselves,andarenotdetermineddirectlyfromthe T10B)andenablethestatisticalsignificanceofaspectrallinetobe
contourplots. robustly determined independently of spectral noise and detector
It is also important to note that while we use the F-test as a effects.ThemethodofMonteCarlosimulationweusedfollowsthe
roughinitialgaugerofthesignificanceofanyline-likeprofilesin sameprocesswhichwasfirstoutlinedbyPorquetetal.(2004),and
the Fe K band we do not claim to robustly detect any absorption isalmostidenticaltothatusedbyT10A.Theprocesswascarried
linesbasedsolelyontheirmeasured(cid:7)χ2andcorrespondingF-test outwiththefollowingsteps.
10 J.Goffordetal.
(i) From the null hypothesis model (i.e. the broad-band con- minimizedpriortosearchingforabsorptionlines,suchthatthere-
tinuum model with all narrow absorption lines in the Fe K band ducedχ2is≈1.0inallcases.Moreover,andasshowninAppendix
removed)wesimulatedbothXIS-FIandXIS-BIspectrausingthe ,wenotethatthevastmajorityofsuspectedabsorptionresiduals
fakeitcommandinXSPECandsubtractedtheappropriatebackground aremanifestedthroughdiscretenarrowdipsinthespectrumrelative
files.Thesimulatedspectrahadthesameexposureastheoriginal tothebest-fittingmodel,whereasanysystematicresidualswould
dataandusedthesamespectralresponsefiles. usuallybebroaderthantheinstrumentresolution.
(ii) WethenfittedthesimulatedXIS-FI(XIS-BI)spectrabetween Thesecondcaveatisassociatedwithspectralcomplexityinthe
0.6and10.0keV(0.6–5.0keV)withthenullhypothesismodelto FeKbandwhichcancomplicatebothlineidentificationandspectral
produceanewandrefinednullhypothesiswhichtakesintoaccount interpretation.Therecanbesignificantatomiccomplexitybetween
theuncertaintyinthenullhypothesismodelitself.Allcontinuum ∼5and7keV,e.g.thenarrowFeKαandFeKβ fluorescencelines,
parameters bar the photon index of the primary power law and broad underlying Fe K lines and ionized Fe XXV–XXVI emission
itsnormalization,andthenormalizationofanybbodycomponent, lines, and the detection of absorption in this regime can depend
were frozen to their best-fitting parameters taken from the real stronglyonhowthesefeaturesaremodelled.Therearethreesources
data to prevent degeneracies between model components during (4C+74.26,MGC-6-30-15,SWIFTJ2127.4+5654;seeFig.B2)in
re-fitting.AnybroadprofileatFeKhaditswidthfixedtothebest- thesampleinwhichbothabroadunderlyingprofileandatleastone
fittingvalue but was allowed tovary in bothcentroid energy and absorptionlinehavebeendetected.Inboth4C+74.26andSWIFT
D
normalization. J2127.4+5654theabsorptionlinesaredetectedathighenergies(i.e. ow
(iii) Fromtherefinednullhypothesismodelwegeneratedasec- E>8keVinthesourcerest-frame)andtheeffectofthebroadFe nlo
a
ondsetofsimulatedXIS-FIandXIS-BIspectraandsubtractedthe lineonthelinedetectionisnegligible.InMCG-6-30-15thelines d
e
d
athpepnrofiptrtieadtewbiatchktghreounnudllfihleysp.oTthheessiessmecoodnedlsainmdultahteedresspuelctatrnatwχe2re hetavale.2a0ls0o5;bMeeinllecroentfiarlm.2ed00w9)itwhhoitchhersuXgg-reasytsotbhsaetrtvhaetoprrieessen(Yceouonfga from
val(uive)wAansurencroersdoelvde.d(σ=10eV)Gaussianwasaddedtothemodnuelll bTrhouasdmFeodlienlelindgoeosfnaobtrinotardodeumciessainoynsliignneifidcoaenstnmotodapelpseyasrtteomaaftfieccst. http://m
at5keVinthesourcerest-framewithintensityinitiallysettozero thedetectionsofFeKabsorptionlinesinthesecases. n
butleftfreetovary between bothpositiveand negative values to ras
.o
probe for both emission and absorption lines. The Gaussian line x
4.5 Consistencychecks fo
wasthensequentiallysteppedbetween5and9.5keV(rest-frame) rd
in 25 eV increments. After each step the |(cid:7)χ2 | was recorded To further test the robustness of the absorption lines detected in jou
relativetoχ2 . noise theco-addedXIS-FIspectraweperformedaseriesofconsistency rna
(v) ThispnruollcesswascarriedoutforT=1000simulatedspectra checks with the individual XIS detectors. If a line is detected in ls.o
per observation yielding a distribution of |(cid:7)χn2oise| under the null two(ormore,iftheXIS2isalsopresent)detectors,thelineisvery arg/
hypothesiswhichessentiallymapsthestatisticalsignificanceofany likelytobearealfeatureintrinsictothesourcespectraratherthanan t N
A
deviationsfromthenullhypothesismodelwhicharesolelydueto artefactofbackgroundsubtraction,systematicnoiseoranassociated S
A
randomphotonnoiseinthespectrum. detectoreffect.TheXIS-BIisnotsuitableforuseasaconsistency G
(vi) Themeasuredsignificanceofthelineintherealspectrum check as it tends to have a much lower S/N above around 5 keV od
d
|(cid:7)χl2ine|wasthencomparedtothevaluesinthe|(cid:7)χn2oise|distribution owing to its lower effective area and higher background. Where ard
toassesshowmanysimulatedspectrahadarandomfluctuationwith absorption has been detected at the P ≥ 95percent level we S
MC p
a detection significance over this threshold value. If N simulated fittedeachindividualbackground-subtractedXIS0,XIS2(where ac
e
spectrahave|(cid:7)χ2 |≥|(cid:7)χ2 |,thentheestimatedconfidencein- present)andXIS3spectrumwiththebest-fittingmodeltotheco- F
tervalforthe(cid:2)obsneor(cid:3)isveedlineflrionemMonteCarlosimulationsisthen addedXIS-FIspectrum.WethenfittedaGaussianabsorptionline, ligh
PLine=1− NLine .Moreover,iftherearetwoabsorptionprofiles with rest-frame energy and normalization left free to vary, at the t C
coMnCsistentwithaTFeXXV–XXVIpair,wecaninferthenullprobability energywheretheabsorptionlineisdetectedintheXIS-FIspectrum, tr on
ofbothlinessimultaneouslybeingafalsedetectionbymultiplying refittedthedataandnotedtheresultantlineparametersforeachXIS A
p
theprobabilitiesofeachindividualline. detector. We note that in SWIFT J2127.4+5654 this consistency ril 5
check could not be conducted as only the XIS 3 spectrum was , 2
0
MonteCarlosignificancesforallabsorptionlinesdetectedinthis available. 1
3
workarelistedincolumn10ofTable2.Absorptioncomplexeswith InallsourcestheresidualsdetectedintheindividualXISspectra
atotalP ≥99percentareconservativelyidentifiedasrobustly haveGaussianparametersconsistentwiththosefoundfortheco-
MC
detected,whilethosewith95percent≤P <99percentareonly addedFIspectrum.InFig.5weshowacomparisonofabsorption
MC
listedasmarginaldetections.Theoveralldetectionrateandglobal line equivalent width (EW), along with the 90percent error bars,
significanceofFeK-bandabsorptionlinesarefurtherdiscussedin as measured independently with the XIS 0 and XIS 3 detectors.
Section5.1. ThedasheddiagonallinerepresentsthepositionwheretheEWis
TherearetwopossiblecaveatsassociatedwiththeaboveMonte equal in each of the detectors; where the EW is consistent at the
Carloprocesswhichbothwarrantfurtherdiscussion.Firstandfore- 90percent level the error bars will overlap this line. In this plot
most,theMonteCarlosimulationsimplicitlyassumethatthenull- the Fe XXV Heα, Fe XXVI Lyα and blended Fe XXV–XXVI lines are
hypothesismodelisthecorrectrepresentationofthecontinuumin plottedseparately,eveninthecaseswherethelinesarefoundtobe
agivensource,andthereforetheMonteCarloprobabilitiesdonot part of a Fe XXV pair. We find that the mean EWs measured with
accountforthepossibilityofcontinuummis-modelling.Giventhis theXIS0andXIS3detectorsareconsistentatthe90percentlevel
possibilityitisimportanttonotethatwehaveattemptedtoachievea (i.e.theerrorbarscrossthediagonallineinFig.5)inallsources.
statisticallyacceptablerepresentationofthebroad-bandspectrum, WherepossiblethisanalysiswasalsocarriedoutusingtheXIS2
sothatnoobviousbroadresidualsarepresent.Carehasbeentaken spectraversusbothXIS0andXIS3.Again,inallcasesthemean
in the Fe K band in particular such that any broad residuals are parameters of the lines were always consistent at the 90percent