XMM-Newton and Suzaku analysis of the Fe K complex in the Seyfert 1 galaxy Mrk 509

0.29 MB·

by  G. Ponti

Mon.Not.R.Astron.Soc.000,1–??(0000) Printed25January2009 (MNLATEXstylefilev2.2)
XMM-Newton and Suzaku analysis of the Fe K complex in the
Seyfert 1 galaxy Mrk 509
G. Ponti1,2,3⋆, M. Cappi2, C. Vignali3, G. Miniutti1,4, F. Tombesi2,3, M. Dadina2,3,
A.C. Fabian5, P. Grandi2, J. Kaastra6,7, P.O. Petrucci8, S. Bianchi9, G. Matt9,
10 2
L. Maraschi and G. Malaguti
9
1APCUniversite´Paris7DenisDiderot,75205ParisCedex13,France
0
2INAF–IASFBologna,ViaGobetti101,I–40129,Bologna,Italy
0
3DipartimentodiAstronomia,Universita`diBologna,ViaRanzani1,I–40127,Bologna,Italy
2
4LaboratoriodeAstrof´ısicaEspacialyF´ısicaFundamental(CAB-CSIC-INTA),PostalAddress:

n LAEFF,EuropeanSpaceAstronomyCenter,P.O.Box78,E-28691VillanuevadelaCan˜ada,Madrid
a 5InstituteofAstronomy,MadingleyRoad,CambridgeCB30HA
J 6SRONNetherlandsInstituteforSpaceResearch,Sorbonnelaan2,3584CAUtrecht,TheNetherlands

3 7AstronomicalInstitute,UniversityofUtrecht,Postbus80000,3508TAUtrecht,TheNetherlands
1 8Laboratoired’AstrophysiquedeGrenoble-Universite´Joseph–Fourier/CNRSUMR5571-BP53,F–38041Grenoble,France
9DipartimentodiFisica,Universita´ degliStudiRomaTre,viadellaVascaNavale84,00146Roma,Italy

] 10INAF/OsservatorioAstronomicodiBrera,ViaBrera28,20121,Milano,Italy
E
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25January2009
p
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o
r ABSTRACT
st WereportonpartiallyoverlappingXMM-Newton(∼260ks)andSuzaku(∼100ks)observa-
a tions of the iron K band in the nearby,brightSeyfert 1 galaxy Mrk 509. The source shows
[
aresolvedneutralFeK line,mostprobablyproducedintheouterpartoftheaccretiondisc.

1 Moreover,the source shows further emission blue–ward of the 6.4 keV line due to ionized
v material. This emission is well reproduced by a broad line produced in the accretion disc,
2 whileitcannotbeeasilydescribedbyscatteringoremissionfromphoto–ionizedgasatrest.
8 ThesummedspectrumofallXMM-Newtonobservationsshowsthepresenceofanarrowab-
8 sorptionlineat7.3keVproducedbyhighlyionizedoutflowingmaterial.Aspectralvariability
1 studyoftheXMM-Newtondatashowsanindicationforanexcessofvariabilityat6.6–6.7keV.
.
1 Thesevariationsmaybeproducedintheredwingofthebroadionizedlineorbyvariationof
0 afurtherabsorptionstructure.TheSuzakudataindicatethattheneutralFeKαlineintensity
9 isconsistentwithbeingconstantonlongtimescales(ofafewyears)andtheyalsoconfirmas
0 mostlikely theinterpretationoftheexcessblueshiftedemissionin termsofa broadionized
: Fe line.The averageSuzakuspectrumdiffersfromthe XMM-Newtononeforthe disappear-
v
i anceofthe7.3keVabsorptionlineandaround6.7keV,wheretheXMM-Newtondataalone
X
suggestedvariability.
r
a Key words: galaxies: individual:Mrk 509 – galaxies: active – galaxies: Seyfert – X-rays:
galaxies
1 INTRODUCTION Guainazzietal.2006;Nandraetal.2007)andthationizedcompo-
nentsoftheline,generallyassociatedwithemissionfromphoto–
DeepinvestigationsoftheFeKbandinthebrightestAGNsallow
and/or collisionally– ionized distant gas are also common (NGC
ustoprobethepresenceofhighlyionizedemitting/absorbingcom-
5506,NGC7213,IC4329A;Bianchietal.2003;Pageetal.2003;
ponentsfromtheinnermostregionsaroundthecentralblackhole.
Reynolds et al. 2004; Ashton et al. 2004; Longinotti et al. 2007;
The high–sensitivity X–ray satellites XMM-Newton and Chandra
see also Bianchi et al. 2002; 2005). The presence of broad (neu-
haveshownthatthepresenceofanarrowcoreofthelowlyionized
tral or ionized) components of Fe K lines can only be tested via
Fe Kα line is nearly ubiquitous (Yaqoob & Padhmanaban 2004;
relativelylongexposuresofthebrightestsources(e.g.,Guainazzi
etal.2006; Nandraetal.2007). Moreover, theobservational evi-
⋆ [email protected] denceforbroadlinesandtheirinterpretationintermsofrelativistic
(cid:13)c 0000RAS
2 G. Pontiet al.
effects may be questioned when an important absorbing ionized the first Suzaku observations overlap over a period of ∼ 25 ks.
componentispresent.Spectralvariabilitystudieshelpindisentan- Eventfilesfromversion2.0.6.13oftheSuzakupipelineprocessing
gling the different, often degenerate, spectral components (Ponti wereusedandspectrawereextractedusingXSELECT.Response
etal.2004; Iwasawaetal.2004; Pontietal.2006; Tombesietal. matricesandancillaryresponsefilesweregeneratedforeachXIS
2007;Petruccietal.2007;DeMarcoetal.,inprep.). using XISRMFGEN and XISSIMARFGEN version 2007–05–
Mrk 509 (z=0.034397) is the brightest Seyfert 1 of the hard 14.TheXIS1cameradataarenotconsideredherebecauseofthe
(2–100keV)X-raysky(Maliziaetal.1999;Revnivtsevetal.2004; relativelyloweffectiveareaintheFeKenergyinterval,whilethe
Sazonov et al. 2007) that is not strongly affected by a warm ab- XIS2 is unavailable for observations performed after November
sorber component (Pounds et al. 2001; Yaqoob et al. 2003). The 2006. We used the data obtained during the overlapping interval
HETG Chandra observation confirms the presence of a narrow tocheckwhethertheEPICpnandMOSdataononehandandthe
componentoftheFeKlinewithanequivalentwidth(EW)of50eV SuzakuXIS0andXIS3dataontheotherhandareconsistentwithin
(Yaqoobetal.2004).Thepresenceofasecondionizedcomponent theinter–calibrationuncertainties.Wefoundanoverallgoodagree-
oftheFeKlineat6.7–6.9keVhasbeenclaimedbyPoundsetal. ment between thedatafromthetwo satellites,theparametersre-
(2001)whofitteditusingarelativisticprofile,butPageetal.(2003) latedtothemainironemissionfeaturesandthepower–lawcontin-
showed that the same spectral feature was consistent also with a uumbeingthesamewithintheerrors(exceptfortheXIS2camera
simpleCompton reflectioncomponent fromdistant material.The above8keV).ThetotalXISobservationtimeisabout108ks.The
broad–bandBeppoSAXspectrumand,inparticular,thesoftexcess, sourceandbackgroundphotonsareextractedfromaregionof4.3
have been fitted by De Rosa et al. (2004) with a reflection com- arcminwithinthesameCCDofthesource.FortheHXD/PIN,in-
ponentfromaionizeddiscinadditiontoaneutralreflectioncom- strumentalbackgroundspectraandresponsematricesprovidedby
ponent.Finally,Dadinaetal.(2005)foundevidenceofabsorption theHXDinstrument teamhavebeen used. Anadditional compo-
duetotransient,relativisticallyred–blue–shiftedionizedmatter. nentaccountingfortheCXBhasbeenincludedinthespectralfits
Here we present the spectral and variability analysis of the ofthePINdata.
complex Fe K band of Mrk 509, using the whole set of XMM- All spectral fits were performed using the Xspec soft-
Newton and Suzaku observations. The paper is organized as fol- ware (version 12.3.0) and include neutral Galactic absorption
lows.Section2describestheobservationsandthedatareduction. (4.2×1020 cm−2;Dickey&Lockman1990),theenergiesarerest
In Sect. 3 the spectral analysis of the EPIC-pn data of the Fe K frameifnotspecifiedotherwise,andtheerrorsarereportedatthe
band(usingphenomenological models) ispresented.Inparticular 90 per cent confidence level for one interesting parameter (Avni
in Sect. 3.3, to check for the presence of an absorption line, the 1976).ThesumofthespectrahasbeenperformedwiththeMATH-
EPIC-MOSdatahavealsobeenconsidered.InSect.3.4thespec- PHA, ADDRMF and ADDARF tools within the HEASOFT
tral variability analysis, within the XMM-Newtonobservations, is package(version6.1).
presented.Sect.4describesthespectralanalysisoftheFeKband
of the Suzaku summed (XIS0+XIS3) data and the detailed com-
parison with the spectrum accumulated during the XMM-Newton
3 FEKBANDEMISSIONOFMRK509:THE
observations. InSect.4.1theHXD-pindataareintroducedinor-
XMM-NewtonDATA
der toestimatetheamount ofreflectioncontinuum present inthe
source spectrum. Finally, a more physically self-consistent fit of TheprimarygoalofthisinvestigationisthestudyoftheFeKline
theEPICspectraofalltheEPICinstruments(EPIC-pnplusthetwo band;therefore,inordertoavoidtheeffectsofthewarmabsorber
EPIC-MOS)isinvestigatedinSect.5.Theresultsofour analysis (althoughnotstrong;Yaqoobetal.2003;Smithetal.2007)andof
arediscussedinSect.6,followedbyconclusionsinSect.7. the soft excess, we concentrate on the analysis of the data in the
3.5–10keVbandonly.Adetailedstudyofthewarmabsorberand
itsvariationswillbeperformedbyDetmersetal.(inprep),wecan
neverthelessanticipatethatthewarmabsorberhasnegligibleeffect
2 OBSERVATIONSANDDATAREDUCTION
in the Fe K energy band and thus on the results presented here.
Mrk509wasobserved5timesbyXMM-Newtonon2000–10–25, Figure 1 shows the source light curve in the 3.5–10 keV energy
2001–04–20, 2005–10–16, 2005–10–20 and2006–04–25. Allob- band obtained from the XMM-Newton pointings. Mrk 509 shows
servations were performed with the EPIC–pn CCD camera oper- variationsoftheorderof∼30percentoverthedifferentobserva-
atinginsmallwindowobservingmodeandwiththethinfilterap- tions,whilealmostnovariabilityisdetectedwithineachobserva-
plied.Thetotalpnobservation timeisofabout 260ks.Sincethe tion.Onlyduringthefourthobservationthesourceshowssignifi-
live–timeofthepnCCDinsmallwindowmodeis71percent,the cantvariability,withameanfractionalrmsofabout0.04.
netexposureofthesummedspectrumisofabout180ks.Theanal- We start the analysis of the XMM-Newton data considering
ysishasbeenmadewiththeSASsoftware(version7.1.0),starting the spectra from the EPIC-pn camera only (including the EPIC-
fromtheODFfiles.Singleanddouble eventsareselectedforthe MOS data only when a check of the significance of a feature is
pndata,whileonlysingleeventsareusedfortheMOScamerabe- required;seeSect.3.3).Wehavefittedasimplepowerlawmodel
cause of a slight pile–up effect. For the pn data we checked that to the 3.5–10 keV data and found that the spectral index steep-
theresultsobtainedusingonlysingleevents(thatallowasuperior enswithincreasingflux.Itgoesfrom1.54±0.03to1.72±0.03for
energyresolution)areconsistentwiththosefromtheMOS,finding fluxes of 2.5×10−11 and 3.3×10−11 erg cm−2 s−1, respectively
goodagreement.Thesourceandbackgroundphotonsareextracted (3.0×10−11 –4.3×10−11 ergcm−2 s−1,inthe2–10 keVband).
fromaregionof40arcsecwithinthesameCCDofthesourceboth WefirstlyphenomenologicallyfittedtheFeKcomplexofeachsin-
forthepnandMOSdata.Responsematricesweregeneratedusing gleobservationwithaseriesofemission-absorptionlines(seealso
theSAStasksRMFGENandARFGEN. §3.3)andcheckedthattheresultsontheparametersofFeKcom-
SuzakuobservedMrk509fourtimeson2006–04–25, 2006– plexobtainedineachobservation areconsistent withintheerrors
10–14, 2006–11–15 and2006–11–27. ThelastXMM-Newtonand (not a surprising result in light of the low statistics of the single
(cid:13)c 0000RAS,MNRAS000,1–??
3
1
norm counts/s/keV 0.10.20.5
1.2 a) χ2=753.9
ratio 1.1 dof=307
1
Figure1.3.5–10keVEPIC–pnlightcurvesoftheXMM-Newtonobserva-
tions. Theabscissa shows the observation time inseconds. Thetime be-
tween the different observations is arbitrary. The black, red, green, blue
andlightblueshowthelightcurvesduringthe2000–10–25,2001–04–20,
2005–10–16,2005–10–20and2006–04–25observations,respectively.
spectraandweaknessoftheionizedfeatures;see§3.4).Hence,we
concludedthatthecontinuumvariationsdonotstronglyaffectthe
observedshapeofthenarrow–bandemission/absorptionstructures
intheFeKband.Thus,inordertoimprovethesignal–to–noisera-
tioandthustodetailthefinestructuresoftheFeKband,thespectra
ofalltheXMM-Newtonobservationshavebeensummed(see§3.4
forthestudyofthesourcespectralvariability).Thesummedmean Figure 2. (Upper panel) Observed–frame 3.5–10 keV summed XMM-
EPIC–pnspectrumhasbeengroupedinordertohaveatleast1000 NewtonEPIC–pnspectrumfittedinthe3.5–5and8–10keVbandwitha
powerlaw.(Panela)Data/modelratio.Thisratioshowsaclearevidence
countsineachdatabin.Moreover,thisbinningcriterionensuresto
foraneutralFeKemissionlineandfurtheremissionfromionizedFe,as
haveatleast 30data–points perkeV inthe4–7keV band, where
wellasothercomplexitiesaround7keV.(Panelb)Data/modelratiowhen
the Fe Kα complex is expected to contribute. This guarantees a
tworesolved emission lines (forthe FeKαandKβ)areincluded inthe
good samplingoftheenergyresolutionof theinstrument andthe
spectralfitting.Strongresidualsarestillpresent,indicativeofionizedFeK
possibilityoffullyexploitingthespectralpotentialsoftheEPICin- emission,whilenoresidualemissionredwardoftheneutralFeKlineap-
struments.Fig.2showstheratiobetweenthedataandthebest–fit pears.(Panelc)Data/modelratiowhenanarrowemissionlineisincluded
powerlaw.Theenergybandusedduringthefithasbeenrestricted inthemodeltoreproducetheionizedemission.(Paneld)Sameaspanelc,
to3.5–5and8–10keV,inordertoavoidtheFeKband,hencemea- butwithasinglebroademissionlineinsteadofanarrowline.Inbothcases
suringtheunderlyingcontinuum.Theresultingbest–fitpower–law (panelcandd),anabsorption feature ispresent around7keV.(Panele)
continuumhasaphotonindexof1.63±0.01andverywellrepro- Data/modelratiowhenanabsorptioncomponent(modeledusingXSTAR)
ducesthesourceemission(χ2=170.0for163degreesoffreedom, andarelativisticionizedlineareaddedtothepowerlawandtheemission
fromneutralFeK.
dof)outsidetheFeKband.TheinclusionoftheFeKbandshows
thatothercomponentsarenecessarytoreproduceit(χ2=753.9for
307dof).Thebadstatisticalresultisexplainedbythepresenceof
clearspectralcomplexityinthe6–7keVband.
3.1 The6.4keVemissionline m s)−2−1 3×10−5 m s)−2−1 6×10−6
Plfioanrneee,alcdaodnoesfdiFsatiegGn.ta2uwsshsitoihawnasetnmheeiusctsrlieaoalnrFleievnieKdetαonctlheinefeomraoatdp6er.l4o,mokbientVaei.nntWinegematihsvseieroreny- αFe K line flux (ph c 2×10−5 Fe K line flux (ph c 2×104×10−6−6
significantimprovementofthefit(∆χ2=392.1fortheadditionof
0
3 dof). The best–fit energy of the line is 6.42±0.02 keV, consis- 0.1 0.15 6.7 6.8 6.9 7 7.1
Fe Kα line width (sigma, keV) Fe K line Energy (keV)
tent with emission from neutral or slightly ionised material. The
Figure3.(Leftpanel)Contourplotofthesigmavs.intensityoftheneutral
line has an equivalent width of 69±8 eV and is clearly resolved
FeKline.(Rightpanel)Contourplotoftheenergyvs.intensityofthenar-
(σ=0.12±0.02keV),asshownbythecontourplotintheleftpanel
rowlineusedtofittheionizedFeKemission.Thenarrowlineenergyisnot
ofFig.3.TheresidualsinpanelbofFig.2shownoexcessredward
consistentwithemissionfromFeXXV(neitherwiththeforbiddenat6.64
ofthisemissionline,whichcouldhavebeenindicativeofemission keV,norwiththeresonantat6.7keV),FeXXVIorFeKβ,whoseenergy
fromrelativisticallyredshiftedneutralmaterial. isindicatedbytheverticaldottedlines(fromlefttoright).
3.2 TheionizedFeKemissionline
Anexcessis,however,presentintherange6.5–7keV(Fig.2,panel
a).IfmodeledwithaFeKβ componentwiththeexpectedenergy
(cid:13)c 0000RAS,MNRAS000,1–??
4 G. Pontiet al.
(fixedat 7.06keV) andforcedtohaveanintensityof 0.15ofthe
Kα(Palmerietal.2003a,b;Basko1978;Molendietal.2003)and ×10×10−6−6
awidthequaltotheFeKαline(i.e.assumingthattheKαandKβ −6−6
lineoriginatefromoneandthesamematerial),thefitimprovessig- mm ×10×10−6−6
npirfiesceannttliyn(t∆heχ62.=52–06..39).keNVonbeatnhdele(pssa,nseilgbniofifcaFnigt.r2e)s.idIfuathlsisafruertshtielrl nornor −2×10−4−2×10−4−6−6
excess is modelled with a narrow Gaussian line (∆χ2=25 for 2
00
additional dof), the feature (EW=12±4 eV) is found to peak at 77..22 77..33 77..44
LLiinneeEE kkeeVV
E=6.86±0.04 keV (see panel c of Fig. 2 and right panel of Fig.
3).Thus,theenergycentroidisnotconsistent withthelinebeing
producedbyeitherFeXXVorFeXXVI(rightpanelofFig.3)in
ascatteringmediumdistantfromtheX-rayssource(Bianchietal.
2002;2004).ThehigherenergytransitionoftheFeXXVcomplex
isthe”resonant line”expected at 6.7keV (seee.g. Bianchi et al.
2005).Thus,tosavethisinterpretation,itisrequiredthatthephoto-
ionizedgashasasignificantblueshift(∼5700km/s,ifthelineisas-
sociatedtoFeXXV)orredshift(∼4500km/s,forFeXXVI).Then,
insteadoffittingtheionizedexcesswithasingleline,wefittedit
withtwonarrowlinesforcingtheirenergiestobe6.7and6.96keV.
Figure4.Superpositionofthepn(green),MOS1(black)andMOS2(red)
Thefitclearlyworsens(χ2=326.7for302dof,correspondingtoa summedspectraofalltheXMM-Newtonobservations.Thedataarefitted,
∆χ2 =−10.1forthesamedof).However,ifthegasisallowedto inthe3.5–5and8–10keVbandswithapowerlaw,absorbedbyGalactic
beoutflowing,thefitimproves(∆χ2=4.3fortheadditionof1new material.Thesamestructuresarepresentinthethreespectra.Inparticular,a
parameter;χ2=312.3for301dof;theEWare8.9and12.4eVfor narrowdropofemissionispresentinalltheinstrumentsatthesameenergy
theFeXXVandFeXXVIlines,respectively)asrespecttothesin- (seeverticaldottedline).(Insetpanel)Confidencecontourplotoftheinten-
glenarrowemissionlineanditresultstohaveacommonvelocity sityvs.energyofthenarrowunresolvedionizedabsorptionwhenusingthe
of3500+1900 km/s. pndataalone(dashedcontours)andincludingtheMOSdataaswell(solid
−1200 contours).Thelinesindicatethe68.3(black),90(red),99(green)and99.9
Alternatively,theexcesscouldbeproducedbyasinglebroad
(blue)percentconfidencelevels.
linecomingfrommatterquiteclosetothesourceofhigh–energy
photons(inthiscasetheFeKemissioniscomposedbyFeKα+β
plusanotherFeKline).Leavingthewidthofthelinefreetovary, andEW=−14.9+5.2eV,E=7.33+0.03keVandEW=−13.1+5.9eV,
−5.5 −0.04 −2.9
thefitimproves,withχ2=311.1(paneldFig.2)and∆χ2 of5.5, inthepnaloneandinthepn+MOS,respectively.
withrespecttothesinglenarrowionizedemissionlinefit,and∆χ2
of1.3forthesamedofwithrespecttothebest–fitmodelwithtwo
narrow ionized lines. The resulting broad ionized Fe K line has 3.4 Timeresolvedspectralvariabilityandtotalrmsspectrum
EW=23±9eVandσ=0.14+0.13keV.Thebest–fitenergyoftheline
−0.08 One of the goals of the present analysis is to search for time–
doesnotchangesignificantly(E=6.86+0.08 keV);however,inthis
−0.16 variationoftheemission/absorptionfeaturesoftheFeKcomplex.
casetheemissionisconsistent(atthe99percentconfidencelevel)
TomeasurepossiblevariationsintheFeKband,themeanEPIC-
witheitherFeXXVorFeXXVI.Althoughthestatisticalimprove-
pnspectraofeachofthe5XMM-Newtonobservations havebeen
ment is not highly significant, in the following we will consider
studied. Thespectraarefittedwiththesamemodel composed by
thatthe∼6.8–6.9keVexcessisindeedassociatedwitharesolved
apowerlawplusthreeemissionlinesfortheFeKα,Kβ(withthe
emissionline.
widthfixedatthebest–fitvalue,σ=0.12keV)andthebroadionized
FeKline.Thelowstatisticsofthespectraofthesingleobservations
preventsusfromthedetectionofsignificantspectralvariabilityof
3.3 Ionizedabsorption?
theweakionisedemission/absorptionlines.TheneutralFeKline
TheXMM-Newtondataalsodisplayanarrowabsorptionfeatureat isbetterconstrainedandwefindthatitsEWisanti–correlatedwith
E∼7keV(observedframe;seeFig.2,paneld).Sincethisfeatureis thelevelofthecontinuum,asexpectedforaconstantline.
veryclosetothebroadexcesswejustdiscussed,itssignificanceand Adifferent,moresensitive,waytodetectanexcessofspectral
intensityaredegeneratewiththebroademission–lineparameters. variabilityisthetotalrmsfunction.TheupperpanelofFig.5dis-
Inorder to gainsome insight, wethen fixedthe broad emission– playstheshapeofthesummedspectrumintheFeKlineband.The
lineparametersatthebest–fitonesobtainedbeforetheadditionof lowerpanelshowsthetotalrmsspectrum(Revnivtsevetal.1999;
anarrow(σfixedat1eV)Gaussianabsorptionlinecomponent.In Papadakis et al. 2005) calculated withtimebins of ∼4.5 ks. The
thiscase,thelineissignificantatthe∼99percentconfidencelevel totalrmsisdefinedbytheformula:
(dashedcontoursofFig.4;∆χ2=15.5for2additionalparameters;
pS2(E)−<σ2 >
see also panel e of Fig. 2). Once the MOS data1 are added, the RMS(E)= err (1)
significanceofthisfeatureincreasesto99.9percent(solidcontours ∆E∗arf(E)
ofFig.4),inbothcases,ofabroadandofanarrowionizedemission where S2 is the source variance in a given energy interval ∆E;
line.ThebestfitenergyandEWofthelineareE=7.28+−00..0032 keV <σe2rr >isthescatterintroducedbythePoissoniannoiseandarf
isthetelescopeeffectiveareaconvolvedwiththeresponsematrix2.
1 The shapes of the emission/absorption lines in the MOS instruments
appearslightlynarrower,althoughconsistentwiththevaluesobtainedwith 2 The total rms spectrum provides the intrinsic source spectrum of the
thepninstrument. variable component. Nevertheless, we measure the variance as observed
(cid:13)c 0000RAS,MNRAS000,1–??
5
Thisfunctionshowsthespectrumofthevaryingcomponent only,
inwhich any constant component isremoved and has been com- 1.2
putedbyusingthedifferentXMM-Newtonobservationsasifthey
werecontiguous.Thetotalrmsspectrummaybereproducedbya ratio 1.1
powerlawwithaspectralindexof2.13(χ2=46.4for43dof).Thus, 1
the variable component is steeper than the observed power law
inthemeanspectrum,inagreement withthementionedobserved
steepeningofthephotonindex(Γ)withflux.TheΓ–fluxcorrela-
tioniscommonlyobservedinSeyfertgalaxiesandhasbeeninter-
pretedasbeingduetotheflux-correlatedvariationsofthepower-
lawslopeproducedinacoronaaboveanaccretiondiscandrelated
tothechangesintheinputsoftseedphotons(e.g.Haardt,Maraschi
&Ghisellini1997; Maraschi &Haardt 1997; Poutanen&Fabian
1999;Zdziarskietal.2003).Thesemodelspredictthepresenceof
apivotpoint,thatwouldcorrespondtoaminimuminthetotalrms
spectrum.Theobservation ofaperfectpowerlawshape(seeFig.
5) indicates that the pivot point (if present) has to be outside the
3–10keVenergyband.Ontheotherhand,theslope-fluxbehaviour
can be explained in termsof atwo-component model (McHardy,
Papadakis&Uttley1998;Shih,Iwasawa&Fabian2002)inwhich
a constant-slope power law varies in normalization only, while a Figure5. Lowerpanel:TotalrmsvariabilityspectrumoftheXMM-Newton
observations. The data (blue crosses) show the spectrum of the variable
harder component remainsapproximately constant,hardening the
component.Thebest–fitmodelisapowerlawwithspectralindexΓ=2.18
spectralslopeatlowfluxlevelsonly,whenitbecomesprominent
(redline)plusaGaussianemissionline(improvingthefitby∆χ2of8.9for
inthehardband.Inthisscenariothespectralindexofthevariable
theadditionof2parameters).Thedashedlinehighlightsthecentroidenergy
component is equal to the one of the total rms spectrum, that is
oftheneutralFeKαline,whilethedottedlineisplacedatthemaximumof
Γ=2.13. thevariabilityexcess,modeledwiththeGaussianemissionline.Theexcess
Moreoverwenotethatattheenergyoftheneutralandionized variabilityenergycorrespondstoadropofemissionoftherealspectrum.
FeKlinecomponents,noexcessofvariabilityispresent,inagree-
mentwiththesecomponentsbeingconstant,whileanindicationfor
anexcessofvariabilityispresentaround6.7keV.Inordertocom- Alsoduringthe4Suzakupointings,Mrk509hasshownlittle
putethesignificanceofthisvariabilityfeature,anarrowGaussian variability,withfluxchanges lowerthan10–15 percent,hamper-
linehasbeenaddedtothemodellingofthetotalrmsspectrum.The inganyspectral variabilitystudy. Fig.6shows theXMM-Newton
best–fit energy of the additional line is 6.69 keV, with a σ fixed (black) andSuzaku XIS0+XIS3(red) summed meanspectra. The
at the instrumental energy resolution, while the resulting ∆χ2 is datawerefitted,inthe3.5–5and7.5–10keVbands,withasimple
8.9fortheadditionof2parameters(thatcorrespondstoanF–test powerlawandGalacticabsorption:theratioofthedatatothebest
significanceof98.8percent).Introducingtheline,thecontinuum fitmodel isshowninFig.6.Thesourceemissionvariedbetween
spectralindexsteepenstoΓ∼2.18.ThedashedlineinFig.5high- theXMM-NewtonandtheSuzakuobservations.Thebest–fitspec-
lightsthecentroidenergyoftheneutralFeKαline,whilethedotted tralindexand the3.5–10 keV band fluxesare:Γ=1.63±0.01 and
line(at∼6.7keV,restframe)isplacedatthemaximumofthevari- Γ=1.71±0.02 and 2.63×10−11 and 3.11×10−11 ergs cm−2 s−1,
abilityexcess.Thisenergycorrespondstoadropofemissioninthe during the XMM-Newton and Suzaku observations, respectively.
realspectrum,asweshalldiscussinmoredetailinSection5. TheneutralandionizedFeKemissionlinesappearconstant,while
some differences are present at 6.7 keV, the same energy where
theXMM-Newtondataweresuggesting anincreaseofvariability.
4 THESuzakuVIEWOFTHEFEKBANDEMISSION Other more subtle differences appears at ∼ 7 keV, where the ab-
sorptionlineimprintsitspresenceintheXMM-Newtondataonly.
As mentioned in §2, the source was also observed with Suzaku.
The first 25 ks Suzaku observation is simultaneous with the last
TheSuzaku spectrumofMrk509shows,ingoodagreement
XMM-Newton pointing. Thesource spectraof all the instruments
withtheXMM-Newtonone,aresolvedneutralFeKlinesmoothly
areinverygoodagreement, duringthesimultaneousobservation.
joiningwithahigherenergyexcess,mostlikelyduetoionizediron
Thespectrumisalsoconsistentwiththepresenceoftheemission
emission (see Fig. 6). Given that no absorption lines around 6.7
andabsorptionlines,asobservedinthemeanXMM-Newtonspec-
keVor7.3keV arepresent intheSuzakudata,thespectrummay
trum,nevertheless,duetothelowstatisticsofthe25ksspectrum
beusefultoinferthepropertiesoftheemissionlinesmoreclearly.
andtheweaknessoftheionizedfeatures,itisnotpossibletoper-
TheXIS0+XIS3Suzakusummedspectrumhasbeenfittedin
formadetailedcomparison.OnlythepresenceofthestrongFeKα
the3.5–10keVbandwithapowerlawplustworesolvedGaussian
linecanbeinvestigated,theionizedemissionandabsorptionlines
emissionlinestoreproducetheemissionfromFeKα+β.Thepa-
arenotconstrainedinthe25ksSuzakuexposure.
rametersoftheFeKαlinearefreetovary,whiletheFeKβ ones
areconstrainedasin§3.2.Thisfitleaveslargeresiduals(χ2=1379.8
for1337dof)intheFeKband.Inthisrespect,itisdifficulttode-
through the instrument. Thus, the sharp features in the source spectrum,
scribe the >6.5 keV excess with a single narrow ionized Fe line
aswellastheeffectsofthefeaturesontheeffectivearea,arebroadenedby
theinstrumentalspectralresolution.Forthisreason,toobtainthetotalrms (eitherduetoFeXXVorFeXXVI).Infact,althoughtheaddition
spectrum,wetakeintoaccounttheconvolution oftheeffective areawith ofanarrowlineissignificant(∆χ2=20.1for2moreparameters),
thespectralresponse. it leaves residuals in the Fe K band. This remaining excess can
(cid:13)c 0000RAS,MNRAS000,1–??
6 G. Pontiet al.
3.5–10keV BEST–FIT SPECTRA
Suzaku
Γ plnorma ENeut. σNeut. ANeut.b(EW)c EIon. σIon./rin AIon.b(EW)c χ2/dof
keV keV keV keV/rg
A 1.72±0.02 1.12±0.02 6.42±0.03 <0.06 1.7±0.5(32) 6.54±0.09 0.40±0.1 4.6±1.2(90) 1344/1340
B 1.72±0.02 1.12±0.02 6.42±0.02 <0.07 2.1±0.5(40) 6.61±0.08 24±10 3.4±0.8(79) 1346/1340
Self-consistentmodel
XMM-Newton
Γ plnorma ENeut. σNeut. ANeut.b Incl. ξ ARefl.Ion.b
keV keV deg ergcms−1
C 1.70±0.01 0.92±0.04 6.41±0.01 0.07±0.01 2.2±0.3 47±2 11+200 0.9+3.0
−7 −0.5
NHd log(ξ) z χ2/dof
5.8+5.2 5.15+1.25 −0.0484+0.012 894.3/876
−4.8 −0.52 −0.013
Table1.Toppanel:Best–fitvaluesofthesummedspectra(XIS0+XIS3)ofallSuzakuobservationsfittedinthe3.5–10keVband.BothmodelAandBinclude
apowerlawandtwoGaussianlinesKα+βtofitthe6.4keVexcess.Inadditiontothisbaselinemodel,eitheranotherGaussiancomponent(ModelA)ora
DISKLINEprofile(ModelB)havebeenaddedtoreproducetheionizedline,respectively.InTablethebest–fitpowerlawspectralindex(Γ)andnormalization
aswellastheFeKαenergy,widthandnormalizationarereportedformodelAandB.Theenergy,widthandnormalizationarereportedwhenaGaussian
profilefortheionizedFeKlineisconsidered(ModelA),whilethebestfitenergy,innerradiusandnormalizationarepresentedwhenaDISKLINEprofile
isfitted(ModelB).Standarddiscreflectivity index,outerdiscradiusanddiscinclination ofα = 3,rout = 400rg and30◦ havebeenassumedforthe
relativisticprofile.Bottompanel:BestfitresultsofthesummedXMM-NewtonEPIC-pnandEPIC-MOSdataofMrk509(fittedinthe3.5–10keVband).The
model(WABS*ZXIPCF*(POW+ZGAUS+ZGAUS+PEXRAV+KDBLUR*(REFLION)))consistsof:i)apowerlaw;ii)twoGaussianemissionlinesfortheFeKα
andKβemission(thislatterhasenergyisfixedtotheexpectedvalue,7.06keV,intensityandwidthtiedtotheKαvalues);iii)aneutralreflectioncontinuum
component(PEXRAVinXspec)withR=1(valuebroadlyconsistentwiththepinconstraintsandthevaluespreviouslyobserved;DeRosaetal.2004),Solar
abundanceandhighenergycutoffoftheilluminatingpowerlawat100keV;iv)aionizeddiscreflectionspectrum(reflionmodel;Ross&Fabian2005)with
thediscinnerandouterradiiandtheemissivityof6,400rg and−3,respectively.Thebestfitdiscinclinationandionizationandthenormalizationofthe
discreflectioncomponentareshown;v)anionizedabsorptioncomponent(ZXIPCF)totallycoveringthenuclearsource.Thebestfitcolumndensity,ionization
parameterandoutflowvelocityarereported.a)Inunitsof10−2photonskeV−1cm−2s−1at1keV;b)Inunitsof10−5photonscm−2s−1;c)InunitsofeV;
d)Inunitsof1022atomscm−2.
obtainanimprovementof∆χ2=9.7forthesamedof(seeTable1,

1.3 Suzaku modelA).
XMM−Newton
↓ ↓ Thus, the Suzaku data indicate that the broad excess at 6.5–
2
1. 6.6keVisindeedduetoabroadlineratherthanablendofnarrow
ionizedFelines.Sincebroadlinesmayarisebecauseofrelativis-
o
rati 1.1 thiycpeoftfheecstsisinbythfietitninngerthreegeioxncessosfatthe6.a5c–c6r.e6tiokneVflowwi,thwaeDteIsSteKdLtIhNiEs
profile.Thestatisticsofthespectrumisnotsuchtoallowustocon-
1 strainalltheparametersoftheionizedDISKLINEmodel.Thus,the
discreflectivityindexhasbeenfixedatthestandardvalue(α=−3,
where the emissivity is proportional to rα), the outer disc radius
9
0. 5 andinclinationsto400gravitationalradii(rg)and30◦,respectively.
Energy (keV) Thebroad lineisconsistent withbeingproduced intheaccretion
disc(Table1,ModelB);however,theemissionfromtheinnermost
Figure 6. XMM-Newton (black) and Suzaku XIS0+XIS3 (red) summed
part of the disc is not required, the lower limit on the inner disc
meanspectra.Thedataarefitted,inthe3.5–5and7.5–10keVbands,with
asimplepowerlaw,absorbedbyGalacticmaterial,andtheratioofthedata radiusbeing10–15rg.AsclearfromFig.6,theSuzakudatadonot
tothebestfitmodelisshown.Thearrowsmarkabsorptionfeaturesinthe requireanyionizedFeKabsorptionstructures.
spectrum.
In order to quantify the differences between the Suzaku and
XMM-Newtonspectra(and,inparticular,therealityoftheabsorp-
bereproduced(∆χ2=5.9for1moreparameter),inaphotoionized tionstructuresat 6.7and7.3keV appearing intheXMM-Newton
gas scenario, by a blend of two unresolved ionized lines, requir- spectrum only) we fixed all the parameters of the Suzaku model
ing three emission lines to fit the FeK band (FeKα+β, Fe XXV (apartfromtheintensityandspectralindexofthedirectpowerlaw)
and FeXXVI). Inthiscase, such asintheanalysis of theXMM- and fit the XMM-Newton data with that model. This corresponds
Newtonmeanspectrum,ablueshiftofthiscomponentissuggested toassumingthattheintrinsiclineshapesdonotvarybetweenthe
(v=2600+2800 kms−1).However,thebest–fitmodel(thisscenario twoobservations.Then,anarrowGaussianlinehasbeenaddedto
−2000
isstrengthenedbythelackofnarrowpeaks)suggeststhattheex- the XMM-Newtonmodel toestimate the significance of the puta-
cessmaybeinfact associatedwithabroad ionizedFeline(over tiveabsorptionstructures.Theimprovementinthespectralfitting
whichthe∼6.7keVand∼7.3keVabsorptionlinesaremostlikely isevident, asindicated bythe ∆χ2=28.3 and 22 inthe case of a
superimposed, butduring theXMM-Newtonobservation only). In lineatE=6.72±0.04keVandE=7.29±0.04keV,respectively.The
factconsideringabroadFelineinsteadofthetwonarrowlineswe presence of these spectral features only in the XMM-Newton ob-
(cid:13)c 0000RAS,MNRAS000,1–??
7
servationsisthusindicativeofvariabilityatenergies∼6.6–6.7and therelativisticprofile.Standardvaluesfortherelativisticprofileare
∼7.3keV. assumed,withthediscinnerandouterradiiandtheemissivityof6,
400r ,and−3,respectively.Finally,the∼7.3keVabsorptionline
g
hasbeenfittedwithaphotoionisedabsorptionmodel(zxipcfmodel
4.1 TheSuzakupindatatoconstrainthereflectionfraction inXspec;Milleretal.2007;Reevesetal.2008;ModelC,Table1),
assumingatotalcoveringfactor.
We add the pin data to measure the amount of reflection contin-
Table1 shows thebest–fit parameters. Once thepresence of
uum. We note that the pin data provide a good quality spectrum
thereflectioncontinuumistakenintoaccount,thepowerlawslope
upto50keV. Themodel usedinvolvesadirectpower lawplusa
neutralreflectioncomponent(pexravmodelinXspec;Magdziarz becomessteeper(Γ=1.70±0.01,∆Γ∼0.07)ascomparedtothefit
with a simple power law and emission absorption lines (see §3).
& Zdziarski 1995) plus the Fe Kα+β resolved lines and a broad
ThebestfitenergyoftheneutralFeKαlineisE=6.41±0.01keV,
(DISKLINE)component oftheline.AsformodelBwefixsome
oftheparametersoftheDISKLINEprofile(discinclination=30◦, consistentwithbeingproduced byneutralmaterial,andresultsto
benarrower(σ=0.07±0.01keV)thaninthepreviousfits.Theion-
r =400r andα=-3).Moreoverweassumeahigh–energycutoff
out g
ized emission line is fitted with a ionized disc reflection model.
of 100 keV and Solar abundance. Thus, by fitting the 3–50 keV
band data, we obtained a reflection fraction R = 0.4+0.6 and a The only free parameters of such a component are the inclina-
spectral index Γ=1.76+0.12. The total EW of the emi−ss0i.o2n lines tion and ionisation parameter of the disc that result to be 47±2◦
−0.03 andξ=11+200 ergcms−1 (Model C,Table1). Thematerial pro-
above the reflectedcontinuum (about 1.2 keV) isbroadly consis- −7
ducing the 7.3 keV absorption feature in the XMM-Newton data
tent with the theoretical expectations (Matt et al. 1996) and with
has to be highly ionized, as also indicated by the absence of a
whatobservedinComptonthickSeyfert2galaxies,wherethepri-
strongcontinuumcurvature.Infact,thebestionizationparameter
mary continuum is absorbed and only the reflection is observed.
Nevertheless,alsoforthissource,asalreadyknownfromprevious islog(ξ)=5.15+−10..2552andthecolumndensityNH =5.8+−54..28×1022
cm−2.Neverthelesstheobservedenergyoftheabsorptionfeature
studies(Zdziarskietal.1999), weobservethatthespectral index
does not correspond to any strong absorption features, thus there
andthereflectionfractionaredegenerate and stronglydepend on
isevidenceforthisabsorptioncomponenttobeoutflowingwitha
theenergybandconsidered. Infact,ifthe2–10keV bandiscon-
sainddertehde,pthoewreerfl–leacwtiopnhofrtaocntiionndeinxcorefaΓse=s1,.r8e8s+ul0t.i0n3g.tTohbeetoRta=l1E.1W+−00o..25f χsh2ifitsv89=4.−30fo.0r488746+−d00o..00f11.23c(∼14000+−34620000kms−1).Theresulting
−0.02
theFeemissionlinesabovethereflectedcontinuumareabout750
eV.Againthesevaluesarebroadlyinagreementwithexpectations
(Mattetal.1996).
6 DISCUSSION
Thisstudyclearlyshowsthatlongexposuresareneedtodisentan-
5 APHYSICALLYSELF-CONSISTENTFIT:POSSIBLE glethedifferentemitting/absorbingcomponentscontributingtothe
ORIGINOFTHESPECTRALFEATURES shape–variability of the Fe K complex in Seyfert galaxies. Here
wediscusstheoriginofbothneutralandionizedemissionandab-
TheanalysisoftheXMM-NewtonandSuzakudatashowsevidence sorption Fe linesin Mrk 509 which allow to have insights in the
forthepresenceof:i)aresolved,althoughnotverybroad,(σ∼0.12 innermostregionsoftheaccretionflow.
keV)neutralFeKαlineandassociatedFeKβemission;ii)anion-
izedFeKemissionlineinconsistentwithemissionfromadistant
scatteringmaterialatrestandmostlikelyproducedintheaccretion
6.1 Neutral/lowlyionizedFeemissionline
disc; iii) an absorption line at ∼7.3 keV, present in the summed
spectrumofallXMM-Newtonobservationsonly;iv)anindication Oncethebroadionizedlineisfitted,thewidthoftheFeKαline
foranenhancementofvariability-bothbyconsideringtheXMM- lowers to a value of 72±11 eV (see Fig. 3) that corresponds to
Newtondataaloneandbycomparisonbetweenthetwodatasets-at a FWHM(Fe Kα)=8000±1300 km s−1 (see Model C, Table 1).
∼6.7keVthatcouldbeeitherduetothehighvariabilityofthered ThisvalueisslightlyhigherthanthatmeasuredbyYaqoob&Pad-
wingofthebroadionizedFeKline,possiblyassociatedwithavari- manabhanwitha∼50ksHETGChandraobservation(2820+2680
−2800
ationoftheionisationofthedisc,ortoasecondionizedabsorption km s−1). The FWHM of the Fe Kα line islarger than the width
line. of the Hβ line (FWHM(Hβ)=3430±240 km s−1; Peterson et al.
These emission/absorption components are partially inter– 2004;Marzianietal.2003),indicatingthattheFelineisproduced
connectedtoeachothergiventhelimitedCCDresolutiononboard closertothecenter thantheopticalBLRand, ofcourse, thanthe
XMM-NewtonandSuzaku.Thuswere–fittheXMM-Newton(both torus postulated in unified models; we note that a wide range of
thepnandMOSinthe3.5–10keVenergyband)datawithamodel FWHMvaluesisobservedfortheBLRandtheFeKlinesinlocal
containingcomponentsthatbetterdescribethephysicalprocesses Seyfertgalaxies(Nandra2006). However, theUVandsoftX-ray
occurringintheAGN.Inparticular,weconsidertwoGaussianlines spectraofMrk509showevidenceforthepresenceofbroademis-
for the Fe Kα and Kβ emission plus a neutral reflection compo- sionlineswithFWHMof 11000kms−1 (Krissetal.2000). The
nent (PEXRAVin XSPEC) witha reflection fraction R = 1 (con- origin of these UV and soft–X lines is still highly debated, nev-
sistentwiththeconstraintsgivenbytheSuzaku pindata).TheFe ertheless they may indicate that the BLR region is stratified, i.e.
Kα line has an equivalent width of 1 keV above the reflection thattheselinesarenotproducedintheopticalBLRbutinthein-
continuum. Moreover, we fit the broad ionized Fe K line with a ner part of a stratified BLR region (see also Kaastra et al. 2002;
fullyself–consistent relativisticioniseddiscreflectioncomponent Costantinietal.2007),possiblyascloseas2000r fromthecen-
g
(reflion model in Xspec; Ross & Fabian 2005, convolved with a ter(about 0.012pc, beingthemassoftheblackholeinMrk509
LAORkernel;KDBLURinXspec). MBH ≃1.43±0.12×108 M⊙ Petersonetal.2004;Marzianietal.
Thestatisticspreventsusfromconstrainingtheparametersof 2003). Nevertheless, if the line isproduced in the innermost part
(cid:13)c 0000RAS,MNRAS000,1–??
8 G. Pontiet al.
ofastratifiedBLR,itwouldrequireeitherahighercoveringfrac- abilitybetweentheXMM-NewtonandSuzakuobservationspoints
tion or a higher column density than generally derived from the towardsanoriginwithinMrk509.
optical and ultraviolet bands. Simulations by Leahy & Creighton An hint of variability is observed around 6.7 keV both in
(1993)showthatabout70percentofthesky,asseenbythecen- the XMM-Newton data and by comparing the XMM-Newton and
tralsource,hastobecoveredinordertoproducetheFeKαline, Suzaku spectra. This could be due in principle to variability in
ifthebroadlinecloudshavecolumndensitiesofabout1023cm−2, theredwingof theionizedemissionline.However, thetotalrms
whilethetypicalvaluesfortheBLRcloudscoveringfractionsare spectrum shows a peak of variability that is consistent with be-
oftheorderof10–25percent(Davidson&Netzer1979;Goad& ingnarrow,thusitmaysuggestanalternativeexplanation.Indeed,
Koratkar1998).Alternatively,theFeKαlinemaybeproducedby theobserveddifferencebetweentheXMM-NewtonandSuzakuFe
reflectionbytheouterpartoftheaccretiondisc. K line shapes could be due to a further ionized absorption com-
ponent, present only the XMM-Newton observations, with a col-
umn density N =5.4+4.8×1021 cm−2 and ionization parameter
H −4.4
6.2 IonizedFeemissionlines log(ξ)=2.04+0.43.Whenthestructureat6.7keVisfittedwithsuch
−0.60
acomponent,anabsorptionstructureappearsaround7.3keV,nev-
ThespectrumofMrk509showsemissionfromionizediron,con-
erthelessitsequivalentwidthisnotstrongenoughtoreproducethe
sistentwitheitherFeXXVorFeXXVI,implyingphotoionizedgas
total absorption feature; moreover, it appears at slightly different
outflowingorinflowingrespectively.Alternatively,theionizedFe
energy,notcompletelyfittingthe∼7.3keVline.Thus,theabsorp-
Kemission maybeproduced byreflectionfromtheinner part of
tion structures at 6.7 and the one at 7.3 keV may be connected
theaccretiondisc.
and they may be indicative of another absorption screen. If this
Infact,boththeXMM-NewtonandtheSuzakudataareconsis-
furtherlowerionizationabsorptioncomponentispresent,different
tentwiththetwoscenarios, evenifaslightlybetter fit(∆χ2=5.5
absorption feature would be expected (due to the low ionization
and 9.7 for XMM-Newton and Suzaku, respectively) is obtained
and high column density) at lower energies. Smith et al. (2007)
in the case of broad line. Moreover in the case of narrow emis-
analyzed the RGS data and detected two absorption components
sion lines the emitting gas should have a significant outflow (for withphysicalparameterssimilar(log(ξ)=2.14+0.19 and3.26+0.18;
rFeespXeXctViv,evly∼)3o5r00inaflnodw2(6f0o0rkFme Xs−X1VfoI,rvX∼M4M50-N0ekwmtosn−a1n)dwSiuthzavkeu-, NH=0.75+−00..1191and5.5+−11..34×1021cm−2)toth−e0.o1n2esthatwe−i0n.f2e7r,
strengtheningthisinterpretation.Thereisalsoevidenceforanother,
locitieshigherthanwhatgenerallyobserved(Reynoldsetal.2004;
higherionization,mildlyrelativistic,andvariableionizedcompo-
Longinottietal.2007;butseealsoBianchietal.2008thatdetect
nentintheXMMdata.Thestudyofthismoreextremecomponent
an outflow of v=900+500 km s−1). On the other hand, the high
−700 isaddressedinanotherpaper(Cappietal.,inpreparation).
radiativeefficiencyofthesource(η=0.12;Woo&Urry2002)sug-
The observation of highly ionized matter in the core of
gests that the accretion disc is stable down to the innermost re-
Mrk509isinlinewithitshighBHmassandaccretionrate.Infact,
gions around the BH, where the reflection component should be
weremindthatattheEddingtonlimittheradiationpressureequals
shaped by relativisticeffects. For these reasons, although an out-
the gravitational pull, however the densities of the matter lowers
flowingemittinggasisnotexcluded, thebroadlineinterpretation
withtheBHmass(Shakura&Sunyaev1976).Thustheionization
seemsfavoured. Infact, theprofileof thelineiscompatible with
ofthematerialsurroundinghighaccretionrateandBHmassAGNs,
being shaped by relativistic effects, consistent with its origin be-
suchasMrk509,shouldbehigherthannormal.Westress,however,
inginthesurfaceofanaccretiondisc,invicinityofablackhole.
thatinordertodetailthephysicalparametersoftheionisedemit-
Nevertheless, the width of the line is not a compelling evidence.
ter/absorber,furtherlongobservationsarerequired.
Theobserved broadening ofthelinecanbereproduced alsowith
theComptonizationprocessoccurringintheupperlayeroftheion-
izedaccretiondisc.Moreover,westressthatthemainevidencesfor
7 CONCLUSIONS
thepresence of abroadFeK linecomesfromthemeansummed
spectrum. The process of summing spectra, although is a power- The Fe K band of Mrk 509 shows a rich variety of emis-
fulwaytoextractinformation,mightbedangerousinpresenceof sion/absorption components. The XMM-Newton and Suzaku data
spectral variability and when applied toobservations taken many showsevidenceforthepresenceof:
years apart. Thus, the final answer on the origin of these ionized
• a resolved, although not very broad, (σ ∼0.07 keV) neutral
lineswillbeobtainedwitheitherahigherresolutionobservationor
FeKαlineandassociatedFeKβ emission.Thewidthoftheline
withsignificantlylongerXMM-Newtonexposures.
suggeststhatthe6.4keVlineisproduced intheouterpartofthe
accretion disc (the broad line region or torus emission seem un-
likely).Themeasuredreflectionfractionisconsistent inthiscase
6.3 IonizedFeabsorptionlines
with the intensity of the line, while a covering factor or column
The XMM-Newton data indicate the presence of a highly ion- density higher than generally observed would be required if the
ized absorption component, the best fit column density being linewereproducedintheBLRorthetorus;
N =5.8+5.2×1022 cm−2 andionizationlog(ξ)=5.15+1.25.More- • both the Suzaku and the XMM-Newton data show an excess
H −4.8 −0.52
over, fittingtheabsorption withthis model, it results that the ab- due to ionized Fe K emission. Both datasets show a superior fit
sorberhastobeblueshiftedby0.0484+0.012c.Theblueshiftcorre- whenabroadionizedlinecomingfromthecentralpartsoftheac-
−0.013
spondstoanoutflowvelocityof∼14000kms−1.Thestructureim- cretion disc is considered. The data are inconsistent with narrow
pliesasignificantblueshiftiftheabsorberislocatedinthecoreof emissionfromadistantscatteringmaterialatrest,whileitcannot
Mrk509but,consideringthesystemicvelocityofthegalaxy,itsen- beexcludedifthegasisoutflowing(v∼3500kms−1)
ergyisalsoconsistentwithalocalabsorber(McKernanetal.2004; • bothEPIC–pnandMOSdatashowanabsorptionlineat∼7.3
2005;Risalitietal.2005;Youngetal.2005;Miniuttietal.2007; keV,presentinthesummedspectrumofallXMM-Newtonobserva-
but seealso Reeveset al. 2008). Nevertheless, the observed vari- tionsonly.Thiscomponentconfirmsthepresenceofhighlyionized,
(cid:13)c 0000RAS,MNRAS000,1–??
9
outflowing(v∼14000 s−1),gasalongthelineofsight. Thecom- Kaastra,J.S.,Steenbrugge,K.C.,Raassen,A.J.J.,vanderMeer,
parisonbetweenXMM-NewtonandSuzakusuggestsavariabilityof R.L.J.,Brinkman,A.C.,Liedahl,D.A.,Behar,E.,&deRosa,
thiscomponent; A.2002,A&A,386,427
• ahintofanenhancementofvariability-bothbyconsidering Kriss,G.A.,etal.2000,ApJ,538,L17
theXMM-Newtondataaloneandbycomparisonbetweenthetwo Magdziarz,P.,&Zdziarski,A.A.1995,MNRAS,273,837
datasets-at∼6.7keVthatcouldbeeitherduetothehighvariabil- Malizia,A.,Bassani,L.,Zhang,S.N.,Dean,A.J.,Paciesas,W.S.,
ityoftheredwingofthebroadionizedFeKline,possiblyasso- &Palumbo,G.G.C.1999,ApJ,519,637
ciatedwithavariationoftheionisationofthedisc,ortoasecond Maraschi,L.,&Haardt,F.1997,IAUColloq.163:AccretionPhe-
ionizedabsorptionline. nomenaandRelatedOutflows,121,101
Marziani,P.,Sulentic,J.W.,Zamanov,R.,Calvani,M.,Dultzin-
Hacyan,D.,Bachev,R.,&Zwitter,T.2003,ApJS,145,199
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ACKNOWLEDGMENTS
McHardy, I.M.,Papadakis, I.E.,&Uttley,P.1998, TheActive
Thispaper isbasedonobservations obtained withXMM-Newton, X-raySky:ResultsfromBeppoSAXandRXTE,509
anESAsciencemissionwithinstrumentsandcontributionsdirectly McKernan,B.,Yaqoob,T.,&Reynolds,C.S.2004,ApJ,617,232
fundedbyESAMemberStatesandNASA.Thisworkwaspartly McKernan, B., Yaqoob, T., & Reynolds, C. S. 2005, MNRAS,
supported by the ANR under grant number ANR-06-JCJC-0047. 361,1337
GP,CVandSBthankforsupport theItalianSpaceAgency(con- Miller, L., Turner, T. J., Reeves, J. N., George, I. M., Kraemer,
tracts ASI–INAF I/023/05/0 and ASI I/088/06/0). GM acknowl- S.B.,&Wingert,B.2007,A&A,463,131
edge funding from Ministerio de Ciencia e Innovacio´n through a Miniutti,G.,etal.2007,PASJ,59,315
Ramo´n y Cajal contract. GP thanks Regis Terrier, Andrea Gold- Molendi,S.,Bianchi,S.,&Matt,G.2003,MNRAS,343,L1
wurm and Fabio Mattana for useful discussion. We would like Nandra,K.2006,MNRAS,368,L62
to thank the anonymous referee for the detailed reading of the Nandra,K.,O’Neill,P.M.,George,I.M.,&Reeves,J.N.2007,
manuscript andfor thecomments thatgreatlyimprovedtheread- MNRAS,382,194
abilityofthepaper. Page,M.J.,Davis,S.W.,&Salvi,N.J.2003,MNRAS,343,1241
Palmeri, P., Mendoza, C., Kallman, T. R., Bautista, M. A., &
Mele´ndez,M.2003,A&A,410,359
Palmeri,P.,Mendoza,C.,Kallman,T.R.,&Bautista,M.A.2003,
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