Kinematic signatures of AGN feedback in moderately powerful radio galaxies at z

28 Pages·2016·3.13 MB·English

A&A586,A152(2016) Astronomy
DOI:10.1051/0004-6361/201526872 &
(cid:2)c ESO2016 Astrophysics
Kinematic signatures of AGN feedback in moderately powerful
∼ (cid:2)
radio galaxies at z 2 observed with SINFONI
C.Collet1,N.P.H.Nesvadba1,C.DeBreuck2,M.D.Lehnert3,P.Best4,J.J.Bryant5,6,7,R.Hunstead5,
D.Dicken1,8,andH.Johnston5
1 Institutd’AstrophysiqueSpatiale,CNRS,CentreUniversitaired’Orsay,Bat.120−121,91405Orsay,France
e-mail:[email protected]
2 EuropeanSouthernObservatory,Karl-SchwarzschildStrasse,GarchingbeiMünchen,Germany
3 Institutd’AstrophysiquedeParis,CNRS&UniversitéPierreetMarieCurie,98bis,bdArago,75014Paris,France
4 SUPA,InstituteforAstronomy,RoyalObservatoryofEdinburgh,BlackfordHill,EdinburghEH93HJ,UK
5 SydneyInstituteforAstronomy(SIfA),SchoolofPhysics,TheUniversityofSydney,NSW2006,Australia
6 AustralianAstronomicalObservatory,POBox915,NorthRyde,NSW1670,Australia
7 ARCCentreofExcellenceforAll-skyAstrophysics(CAASTRO),Australia
8 LaboratoireAIMParis-Saclay,CEA/DSM/Irfu,OrmedesMerisiers,Bât.709,91191Gif-sur-Yvette,France
Received1July2015/Accepted19August2015
ABSTRACT
Mostsuccessful galaxyformationscenariosnow postulatethattheintensestarformationinmassive,high-redshift galaxiesduring
their major growth period was truncated when powerful AGNslaunched galaxy-wide outflows of gas that removed large parts of
theinterstellarmedium.SINFONIimagingspectroscopyofthemostpowerfulradiogalaxiesatz∼ 2showclearsignaturesofsuch
winds,butaretooraretobegoodrepresentativesofagenericphaseintheevolutionofallmassivegalaxiesathighredshift.Herewe
presentSINFONIimagingspectroscopyoftherest-frameopticalemission-linegasin12radiogalaxiesatredshifts∼2.Oursample
spans a range in radio power that is intermediate between the most powerful radio galaxies with known wind signatures at these
redshiftsandvigorousstarburstgalaxies,andareabouttwoordersofmagnitudemorecommonthanthemostpowerfulradiogalaxies.
Thus,ifAGNfeedbackisagenericphaseofmassivegalaxyevolutionforreasonablevaluesoftheAGNdutycycle,thesearejust
thesourceswhereAGNfeedbackshouldbemostimportant.Oursourcesshowadiversesetofgaskinematicsrangingfromregular
velocitygradientswithamplitudesofΔv=200−400kms−1consistentwithrotatingdiskstoveryirregularkinematicswithmultiple
velocityjumpsofafew100kms−1.Linewidthsaregenerallyhigh,typicallyaroundFWHM=800kms−1,moresimilartothemore
powerfulhigh-zradiogalaxiesthanmass-selectedsamplesofmassivehigh-zgalaxieswithoutbrightAGNs,andconsistentwiththe
velocityrangeexpectedfromrecenthydrodynamicmodels.AbroadHαlineinonetargetimpliesablackholemassofafew109 M(cid:4).
Velocityoffsetsofputativesatellitegalaxiesnearafewtargetssuggestdynamicalmassesofafew1011 M(cid:4)foroursources,akintothe
mostpowerfulhigh-zradiogalaxies.Ionizedgasmassesare1−2ordersofmagnitudelowerthaninthemostpowerfulradiogalaxies,
andtheextinctioninthegasisrelativelylow,uptoA ∼2mag.Theratiooflinewidths,σ,tobulkvelocity,v,issolargethateven
V
thegasingalaxieswithregularvelocityfieldsisunlikelytobegravitationallybound.Itisunclear,however,whetherthelargeline
widthsareduetoturbulenceorunresolved,localoutflowsasaresometimesobservedatlowredshifts.Wecompareoursourceswith
setsofradiogalaxiesatlowandhighredshift,findingthattheymayhavemoreincommonwithgas-richnearbyradiogalaxieswith
similarjetpowerthanwiththemostpowerfulhigh-zradiogalaxies.Comparisonofthekineticenergywiththeenergysupplyfrom
theAGNsthroughjetandradiationpressuresuggeststhattheradiosourcestillplaysadominantroleforfeedback,consistentwith
low-redshiftradio-loudquasars.
Keywords.galaxies:active–galaxies:high-redshift–galaxies:starformation–galaxies:jets–galaxies:kinematicsanddynamics–
radiocontinuum:galaxies
1. Introduction massfunction,whichisdominatedbyearly-typegalaxies(e.g.,
Bensonetal.2003),whosemassandstructuralpropertiesappear
Itisnowwidelyacceptedthatthesupermassiveblackholesre-
closely related to the mass of their central supermassive black
siding in the vast majority of early-type galaxies and bulges
hole(e.g.,Tremaineetal.2002).
(e.g., Yu & Tremaine 2002) can have a sizeable impact on the
evolution of their host galaxies. Semi-analytic models require Powerful active galactic nuclei (AGNs) release approxi-
a strong source of energy to balance the overcooling of gas matelytheequivalentofthebindingenergyofamassivegalaxy
ontodarkmatterhalosandtoavoidastrongexcessinbaryonic duringtheirshortactivityperiod,eitherintheformofradiation,
mass and star formation in galaxies compared to observations. or through jets of relativistic particles, or both. They are thus
Thediscrepancyisstrongestatthehigh-massendofthegalaxy in principle able to offset the excess cooling out to the highest
galaxymasses(Silk &Rees1998).Ifsufficientlylargepartsof
(cid:4) BasedonobservationscarriedoutwiththeVeryLargeTelescopeof thisenergyaredepositedintheinterstellarmedium(ISM)ofthe
ESOunderProgramIDs084.A−0324and085.A−0897,andatATCA host galaxy, they may drive winds (Di Matteo et al. 2005) or
underProgramIDC2604. turbulence(Nesvadbaetal.2011a).Themechanismsthatcause
ArticlepublishedbyEDPSciences A152,page1of28
A&A586,A152(2016)
this, however,arestill notverywellunderstood.Evenveryba- massivehigh-redshiftgalaxiesoverall,seeninashortbutimpor-
sicquestions,e.g.,whetherfeedbackisdominatedbyradiojets tant phase of their evolution, and we summarize our results in
orthebolometricenergyoutputofradiativelyefficientaccretion Sect.10.
disks,arestillheavilydebatedintheliterature.Thereisclearob-
Throughout our analysis we adopt a flat cosmology with
saetrkvpactiodniastlaenvciedefnrocemththatejnetusccleaunsp,ewrthuirlebtthheeIoSbMsersvtraotinognlayleevvein- H0 =70kms−1Mpc−1,ΩΛ =0.7,andΩM =0.3.
denceforwindsdrivenbyquasarradiationoverkpcscalesisstill
mixed(e.g.,Husemannet al. 2013;Liu et al. 2013;Cano-Díaz
etal.2012;Harrisonetal.2012).Hydrodynamicmodelsofra-
diojetsarenowfindingdepositionratesofkineticenergyfrom 2. Sample
thejetintothegasthatarebroadlyconsistentwithobservations
(Wagneretal.2012). Our sources have a radio power of a few 1027−28 W Hz−1 at
Following the most popular galaxy evolution models, 500 MHz in the rest frame, about 2 to 3 orders of magni-
AGN feedback should have been particularly important in the tude fainter than the most powerful high-redshift radio galax-
early evolution of massive galaxies at high redshift, where ies known, which reach up to nearly 1×1030 W Hz−1 (Miley
AGN-drivenwindsmayhave blownoutthe remaininggaseous & De Breuck 2008, and references therein), but powerful
reservoirsthatfueledthemainphaseofgalaxygrowth,inhibiting enoughtosafelyneglectcontaminationfromintensestarforma-
extended periods of subsequent star formation from the resid- tion.Forcomparison,anintenselystar-formingHyLIRG(hyper-
ual gas. Whereas the jets of powerful radio galaxies in the lo- luminous infrared galaxy) with far-infrared luminosity L =
FIR
calUniverseareknowntoaffectthegaslocallywithinextended 1×1013L(cid:4) wouldproducearest-frame1.4GHzradiopowerof
gas disks (“jet-cloud interactions”, e.g., Tadhunter et al. 1998; 1025.0WHz−1,assumingafar-infrared-to-radioluminosityratio
vanBreugeletal.1985),itwasfoundonlyrecentlythatoutflows of 2.0, as found for high-redshift submillimeter galaxies (e.g.,
driven by the most powerful radio jets in the early universe at Vlahakisetal.2007;Seymouretal.2009;Thomsonetal.2014),
z∼2canencompassveryhighgasmasses,uptoabout1010 M(cid:4) andaradiospectralindextypicalofstarformationofα=−0.7to
in the most powerfulradio galaxies at high redshift(Nesvadba −0.8.Thisisverysimilartothesteepspectralindicesα ∼ −1.0
etal.2006,2008a).Thisissimilartothetypicaltotalgasmasses thatarecharacteristicofhigh-redshiftradiogalaxies,makingit
in massive, intensely star-forming, high-redshift galaxies of a evenmoredifficulttodisentanglethecontributionofAGNsand
few1010 M(cid:4) (e.g.,Greveetal.2005;Tacconietal.2008).This star formationto lower-powerradio sources than those studied
gas is strongly kinematically perturbed with full width at half here.Inspiteoftheirfaintnessrelativetootherhigh-redshiftra-
maximum(FWHM)upto∼2000kms−1andhigh,abruptveloc- dio galaxies, the radio power of fainter sources in this present
ity gradientsofsimilar amplitude,consistentwith theexpected studyisnonethelesscomparabletothatofthemostpowerfulra-
signaturesofvigorousjet-drivenwinds. diogalaxiesknownatlowredshift(e.g.,Tadhunteretal.1993).
Galaxieswithextremeradiopowerat1.4GHzofuptoP1.4 = Our targets come from two different surveys. One is the
few×1029 WHz−1 likethosestudiedbyNesvadbaetal.(2006,
southernsampleof234distantradiogalaxiesofBrodericketal.
2008a)are,however,veryrare,whichraisesthequestionofthe
(2007), Bryant et al. (2009a,b), and Johnston et al. (in prep.),
impact that AGNs may have on their host galaxies when their
whichwerefertohereafterastheMRCR-SUMSSsample.The
radiopowerissignificantlylower.Thepresentpapergivesafirst
other is the sample of radio galaxies within the fields of the
answer to this question. It is part of a systematic study of the
ESO imaging survey (EIS) by Best et al. (2003) and Brookes
warm ionized gas in 49 high-redshift radio galaxies at z ∼ 2
et al. (2006, 2008), which we call the “CENSORS” sample
with SINFONI, which span three decades in radio power and
(“CombinedEIS-NVSSSurveyOfRadioSources”).
two decades in radio size. Our sources cover the lower half of
the radio power of this sample, P = few ×1026−27 W Hz−1 The MRCR-SUMSS sources have steep radio spectral in-
at 1.4 GHz in the rest frame. Tow1a.4rd lower radio power, con- dices α408−843 ≤ −1.0 between 408 MHz and 843 MHz, and
fluxesat408MHzS ≥200mJy.Fromthiscatalogue,wese-
tamination from the non-thermal radio continuum of vigorous 408
lected12moderatelylow-powersourcesatz≥2withP =few
starburstsbecomesincreasinglyimportant.Thehigh-redshiftra- 1.4
×1027 W Hz−1. Theyhaveradiosizes between∼2(cid:7)(cid:7) and24(cid:7)(cid:7) at
dioluminosityfunctionofWillottetal.(2001)andGendreetal.
1.4 GHz frequency, a typical range of radio sizes of powerful
(2010)suggeststhatsuchgalaxiesarefactorsof100morecom-
HzRG.
monthantheverypowerfulradiosources,withco-movingnum-
berdensitiesontheorderofafew10−7Mpc−3,sufficienttorep- The six galaxies with the lowest radio power (P ∼
1.4
resentashort,genericphaseintheevolutionofmassivegalaxies, 1026 W Hz−1) come from the CENSORS survey. This cata-
aswewillarguebelowinSect.9. logueof150radiogalaxiesresultsfromcross-matchingtheESO
The organization of the paper is as follows. In Sect. 2 we Imaging Survey (EIS) patch D with the NVSS radio survey
present our sample and in Sect. 3 our SINFONI near-infrared (Best et al. 2003). Radio sources detected in the NVSS were
(NIR) imaging spectroscopy and ATCA centimeter continuum re-observed at 1.4 GHz with the VLA in the BnA configura-
observations,andthemethodswithwhichwereducedthesedata. tionataspatialresolutionof3(cid:7)(cid:7)−4(cid:7)(cid:7),comparedtotheinitialspa-
In Sect. 4 we present our methods of analysis and the results tialresolutionofthe NVSSof45(cid:7)(cid:7), whichiscompletedownto
for each individual target, before presenting the overall results 7.2mJy.Thismadeitpossibletostudythestructureoftheradio
drawnfromoursampleinSect.5.InSect.6wediscusstheAGN sourcesandtoidentifythe mostlikelyrest-frameopticalcoun-
properties,andinSect.7weuseadditionallineemittersnearour terpartsof102sources.Opticalspectroscopyprovidedredshifts
radiogalaxiestoestimatedynamicalmassesofourhigh-redshift of 81 sources(Brookeset al. 2008).Amongthese, we selected
radio galaxies (HzRGs). In Sect. 8 we compare our data with sixsourceswitharadiopowerofafew×1026WHz−1andappro-
otherclassesofHzRGsbeforediscussingtheimplicationsofour priate redshifts for ground-based NIR follow-up spectroscopy.
resultsforAGNfeedback.WeargueinSect.9thatsourcessim- Three have extended radio morphologies and three have com-
ilartothosestudiedheremaywellbearepresentativesubsetof pact,unresolvedradiocores.
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C.Colletetal.:Moderatelypowerfulhigh-zradiogalaxies
3. Observationsanddatareduction 3.2.Radiocontinuumobservations
3.1.Near-infraredimagingspectroscopy WeobservedourMRCR-SUMSSandCENSORSsourcesintwo
runs on 2012 January 28 and February 02 with the Australia
We observed all MRCR-SUMSS galaxies with the NIR imag- TelescopeCompactArray(ATCA,projectC2604).Observations
ingspectrographSINFONI(Eisenhaueretal.2003)betweenlate were carried out simultaneously at 5.5 and 9.0 GHz using the
2009andearly2010underprogramID084.A-0324attheESO CompactArrayBroadbandBackend,withbandwidthsof2GHz
VeryLargeTelescope.SINFONIobservationsoftheCENSORS andchannelwidthsof1MHz.Thearrayconfigurationwas6A,
sourceswerecarriedoutbetweenlate2010andearly2011under with baselines between 337 and 5939 m. For flux density and
program ID 086.B-0571.All data were taken in Service Mode bandpass calibration we observed PKS B1934−638 at the be-
undervariableconditions. ginningandendofeachsession.Poorphasestabilitywasdueto
SINFONI is an image slicer that operates between 1.1 μm heavyrainandhighhumidity,andthissignificantlyaffectedthe
and 2.4 μm. We used the seeing-limited mode with the largest signal-to-noiseratio.
availablefieldofviewof8(cid:7)(cid:7) × 8(cid:7)(cid:7)andapixelscaleof250mas. Individualsourceswereobservedin13–15five-minutesnap-
AlldataweretakenwiththeH+K gratingwhichcoverswave- shots spread over8.5 h to ensure gooduv coverage;an excep-
lengths between 1.45 μm and 2.4 μm at a spectral resolving tion was NVSS J144932−385657, which set early with only
power R ∼ 1500 (∼200 km s−1). We observed each MRCR- five snapshots spanning 3 h. We did not obtain any new data
SUMSS galaxy for 180−230 min of on-source observing time forCENSORS072becauseweusedincorrectcoordinatesfrom
(300−440 min for the CENSORS sources), split into individ- Brooks et al. (2008). The ATCA observing log is given in
ualobservationsof5min.Mostofourgalaxiesaresmallerthan TableB.2andlistsforeachsourcethedateofobservation,total
the field of view. We therefore adopted a dither pattern where on-sourceintegrationtime,thesecondaryphasecalibratorused,
the object is shifted between two opposite corners of the field andthesynthesizedbeamateachfrequency.
of view, which allows us to use two subsequentframes for the ThedatareductionwasdonewithMiriad(Saultetal.1995)
skysubtractionandmakestakingdedicatedskyframesunneces- in the standard way. We find typical beam sizes of 4(cid:7)(cid:7)×1.5(cid:7)(cid:7)
sary.Thespatialresolutionofourdata islimitedby thesize of at 5.5 GHz and 2.5(cid:7)(cid:7)×0.9(cid:7)(cid:7) with position angles between −6◦
theseeingdisk,whichistypicallyaround1.0(cid:7)(cid:7)forbothsamples. and13◦(exceptforNVSSJ144932−385657,wherePA=−40◦).
The FWHM sizes of the pointspread functions(PSFs) ofindi- DetailsaregiveninTableB.2.
vidualtargetsaregiveninTableB.1.Theyaremeasuredfroma
TheradiomorphologiesareshowninFig.1.Theygenerally
standardstarobservedattheendofeachhourofdatataking.
confirmthosepreviouslymeasuredat1.4GHzand2.4GHzwith
DatareductionreliesonacombinationofIRAF(Tody1993) larger beams. In NVSS J002431−303330 we detect a fainter
andourowncustomIDLroutines(e.g.,Nesvadbaetal.2011b).
second component to the southwest of the main radio emis-
Allframesaredark-subtractedandflat-fielded.Wethenremove
sion below the detectionthresholdof previousobservations.In
the curvaturefrom the spectra in each slit and put them onto a NVSS J234235−384526we tentatively detecta radio core that
commonwavelengthscalebyusingthebrightnight-skylinessu-
is coincidentwith the galaxy.Radio sizes are givenin Table 1.
perimposedoneachframe,usingonlyarclampspectratosetthe
Thelargestangularscale(LAS)givestheseparationbetweenthe
absolutewavelengthscale.Wethenskysubtractourdataandre-
twolobes,ifthesourceisresolved,orthedeconvolvedsize,ifit
arrangethemintothree-dimensionaldatacubes,whicharethen
isnot.
combined.Toaccountforthevariabilityofthenightskywescale
the total flux in each sky frame to the total flux in each object
frame,aftermaskingthetarget.Weusethestandardstarobser- 3.2.1. Relativeastrometricalignmentoftheradio
vationstocorrectfortelluricandinstrumentaleffectsandtoset andSINFONIdata
theabsolutefluxscale.
StudyingtheeffectsoftheradiojetontheISMofhigh-redshift
In this analysis, we discuss the optical emission-line
galaxiesrequiresanaccuraterelativealignmentbetweenthera-
properties of 8 of the 12 MRCR-SUMSS galaxies we ob-
dioandNIRdatasetstobetterthananarcsecond,i.e.,betterthan
served. Two of the other four, NVSS J004136−345046 and
the absolute astrometry of the VLT. Unfortunately, we did not
NVSS J103615−321659,have continuumemission but no line
detecttheradiocoreofmostofourgalaxieswithextendedradio
emission at the redshiftspreviouslymeasuredin the rest-frame
lobes.Moreover,owingtothesmallfieldofviewofSINFONI,
UV. Their redshifts are relatively high, z = 2.6, placing [OIII]
aligningourdatacubesaccuratelywithintheWorldCoordinate
and Hα at wavelengths outside the NIR atmospheric bands,
System(WCS)isnottrivial.Wethereforeregisterourcubesrel-
where the atmospheric transmission is below 10%, and is
ativetotheK-bandimagingofBryantetal.(2009a),whichisac-
strongly variable both in time and in wavelength. At the ex-
curatelyalignedwiththeWCS,andassumethattheradioframe
pectedwavelengthofHα,thetelluricthermalbackgroundisal- ofATCAalignswellwiththeWCS,tobetterthan1(cid:7)(cid:7)(Broderick
ready a factor of ∼10 greater than at 2.2 μm. A third source, etal.2007).Forcompactradiosources(LAS(cid:2)2.0(cid:7)(cid:7)inTable1),
NVSS J233034−330009, was found to coincide with a fore-
weassumethattheK-bandcontinuumisalignedwiththeradio
groundstar afterourdatahadalreadybeentaken(Bryantetal.
source,correspondingtotheassumptionthattheradioemission
2009b). The fourth source, NVSS J210626−314003 shows a
in compact sources originates from the nucleus of the galaxy.
strongmisalignmentbetweentheradiosourceandtheextended
Figure 1 shows the radio contours of the MRCR-SUMSS and
gas,andnogasalongtheradiojetaxis,whichis verydifferent
CENSORS sources,andtheredboxgivestheadoptedposition
fromtheothergalaxiespresentedhere.Thissourcehasalready
oftheSINFONImapsbasedonthismethod.
beendiscussedbyColletetal.(2015),sowedonotdescribeits
characteristicsindetailagain,butwedoincludeitintheoverall
discussion of the propertiesof our sources. For the CENSORS
4. Results
sourceswefocusourdiscussiononthethreesourceswherewe
detected line emission at the redshifts previously measured in For each galaxy we show integrated spectra and emission-line
therest-frameUV. mapsof[OIII]λ5007surfacebrightness,relativevelocities,and
A152,page3of28
A&A586,A152(2016)
20
NN NN NN
10 NVSS 0024 20 NVSS 0040 NVSS 0129
EE EE EE
10
ec] 0 10
s
c
ar 0
[
et
s-10 0
off
-10
-20 -10
-20
-20 -10 0 10 -20 -10 0 10 -20 -10 0 10 20
20 30
NN 20 NN NN
NVSS 0304 NVSS 1449 NVSS 2019
EE EE 20 EE
10 10
c]
se 10
c
ar 0 0
[
set 0
off
-10 -10
-10
-20
-20 -20
-20 -10 0 10 20 -20 -10 0 10 20 -20 -10 0 10 20
20 NVSS 2046 NN 30 NVSS 2106 NNN 20 NVSS 2342 NN
EE 20 EEE EE
ec] 10 10 10
s
c
ar
[ 0
et
s 0 0
off -10
-20
-10 -10
-30
-20 -10 0 10 20 -30 -20 -10 0 10 20 30 -20 -10 0 10 20
offset[arcsec] offset[arcsec] offset[arcsec]
20 20 20
NN NN NN
CEN 020 CEN 105 CEN 118
EE EE EE
10 10 10
c]
e
s
c
ar 0 0 0
[
et
s
off
-10 -10 -10
-20 -20 -20
-20 -10 0 10 20 -20 -10 0 10 20 -20 -10 0 10 20
offset[arcsec]
20 10
NN NN
CEN 129 CEN 134
EE EE
10 5
c]
e
s
c
ar 0 0
[
et
s
off
-10 -5
-20 -10
-20 -10 0 10 20 -10 -5 0 5 10
offset[arcsec] offset[arcsec]
Fig.1.Radiomorphologiesat5.5GHzoftheMRCR-SUMSSsample.Thesizeandorientationoftherestoredbeamisgiveninthebottomleftof
eachpanel.TheredboxindicatesthesizeandlocationoftheSINFONImapspresentedinFig.2.ForNVSSJ144932−385657, giventheshort
observationtimeofthissourceandhencethedeformedbeam,wealsopresentits4.8GHzobservationsfromBryantetal.(2009a),whoobserved
apartoftheirsampleat4.8GHzand8.64GHz.
A152,page4of28
C.Colletetal.:Moderatelypowerfulhigh-zradiogalaxies
Fig.2. Integrated spectra of our sources. Gaussian fitstodetected lines areplotted assolid redlines. Below each spectrum weshow atypical
night-skyspectrumtoillustratethepositionofbrightnight-skylines(dashedlines).Thisspectrumisnottoscale;thenight-skylinesshownare
brighterthantheemissionlinesfromourtargets.Thebottompanelshowsthefitresiduals.
A152,page5of28
A&A586,A152(2016)
Table1.ATCAresults.
SourceID S a S b αc logL d logL e LASf PAg
5.5 9.0 500 1.4
[mJy] [mJy] [WHz−1] [WHz−1] [arcsec] [deg]
NVSSJ002431−303330 21.1 11.1 −0.99±0.05 27.9 27.5 16 18
NVSSJ004000−303333 10.0 3.4 −1.34±0.06 28.6 27.9 15 91
NVSSJ012932−385433 29.2 14.3 −1.06±0.02 28.1 27.6 <1.4 ...
NVSSJ030431−315308 13.4 5.9 −1.25±0.03 28.1 27.5 <3.6 ...
NVSSJ144932−385657 ... ... −0.99±0.05 27.9 27.4 13.4 59
NVSSJ201943−364542 11.7 10.2 −1.13±0.07 28.0 27.5 31.4 65
NVSSJ204601−335656 9.8 9.1 −1.14±0.04 28.0 27.6 3.6 ...
NVSSJ210626−314003 19.8 22.4 −1.05±0.05 28.1 27.6 50.0 98
NVSSJ234235−384526 6.0 2.2 −1.38±0.03 28.5 27.9 19.6 54
NVSSJ094604−211508(CEN020) 14.5 8.0 −1.02±0.04 27.3 26.8 <2.9 0
NVSSJ094724−210505(CEN105) 2.2 0.8 −1.18±0.09 27.5 26.8 28.4 95
NVSSJ094748−204835(CEN118) 1.9 0.6 −1.29±0.15 27.6 26.9 10. 0
NVSSJ095226−200105(CEN129) 2.7 1.7 −0.82±0.01 26.9 26.5 5.0 95
NVSSJ094949−213432(CEN134) 2.4 1.0 −1.08±0.09 27.0 26.6 4.5 131
Notes.(a) Fluxmeasuredat5.5GHz.(b) Fluxmeasuredat9.0GHz.(c) Radiospectralindex.(Sect.6.1).(d) Radiopowerat500MHz.(e) Radio
power at 1.4 GHz inthe rest frame. (f) Largest angular size, corresponding tothe separation between the twolobes (when detected) or to the
deconvolvedsizeforcompactsources.Forunresolvedsourcesthedeconvolvedsizesat5.5GHzand9.0GHzarebothgiven.(g) Positionangle
measuredfromnorthtoeast.
FWHMlinewidths(Figs.2toA.2andTables2and3).Unless thespectrabeforefittingtheemissionlines.Toperformthissub-
statedotherwise,wegiveintrinsicFWHMs,FWHM , that traction,wemaskstrongemissionlinesandstrongnight-skyline
intrinsic
are corrected for (cid:2)instrumental resolution FWHMinst, setting residualsandfitafifth-orderpolynomialovertheirwholespec-
FWHM = FWHM2 −FWHM2 . The instrumental trum,whichwesubtractafterward.
intrinsic obs inst
resolution, FWHM , is wavelength dependent and was mea-
inst
suredfromthewidthofnight-skylines.Mapsareonlygivenfor 4.1.Descriptionofindividualsources
spatialpixelswherethesignal-to-noiseratioofthelinecoreex-
ceeds5.WeusedaMonteCarlomethodtoconfirmthatthiswas 4.1.1. NVSSJ002431−303330
agoodvaluewithwhichtorobustlymeasurethelineproperties
NVSSJ002431−303330isadoubleradiosource,dominatedby
in spite of strong non-Gaussianities in the noise related to the
abrightcomponentassociatedwiththeopticalcounterpart,and
imperfectnight-skylinesubtraction,badpixels,andpotentially
aweakercomponentat16(cid:7)(cid:7) towardsouthwest(Fig.1).We find
intrinsiclineprofiles.
thissourceataredshiftofz = 2.415±0.001,whichisingood
Integratedspectraincludeallpixelswhere[OIII]λ5007isde-
agreementwiththeestimateofJohnstonetal.(inprep.)fromthe
tectedatasignificantlevel.Weadopttheredshiftestimatedfrom
rest-frameUV lines, with zuv = 2.416±0.001.In the H band,
the brightest pixels near the center of the galaxy as systemic.
wedetectthe[OIII]λ4959,5007doubletandHβ.IntheK band,
Beforeaddingthespectrumofapixel,weshiftittothesystemic
we find Hα and [NII]λ6548,6583, which are strongly blended
redshiftin ordertoavoidartificialbroadeningofthelinein the
owing to their large intrinsic widths. The Hα line has a broad
integratedspectrumbythelarge-scalevelocitygradient. component with FWHM = 3250 km s−1. Figure 2 shows the
Foreachgalaxywealsomappedthesurfacebrightness,rela-
integratedspectrumofthissource.Alllinepropertiesarelisted
tivevelocitytothesystemicredshiftandtheFWHMlinewidths
inTable2.
of[OIII]λ5007(Figs. 3to 4) byfitting Gaussian profilesto the
As shown in Fig. 3, NVSS J002431−303330 has a
lines extracted from small apertures across the cube. Aperture
sizes are 3 pixels × 3 pixels, correspondingto 0.4(cid:7)(cid:7) × 0.4(cid:7)(cid:7), or strong continuum associated with a bright emission-line
5 pixels× 5 pixels(0.6(cid:7)(cid:7) × 0.6(cid:7)(cid:7)) forthe faintestregionsof the region with [OIII]λ5007 surface brightness of (5−25) ×
10−16 ergs−1cm−2arcsec−2. Line widths in this region are
source. This helps to improve the signal-to-noise ratio of the
very broad, FWHM ∼ 1200 kms−1, and the velocity field
data, but still oversamples the seeing disk and avoids loss of
is perturbed with two small, unresolved regions that show
spatial information. Since the sizes of the extended emission-
abrupt velocity jumps relative to their surroundings with rela-
line regions,S , are typically onlya few times largerthan
maj,obs tiveredshiftsof about250kms−1 ineach region.Thisarea ex-
thesizeoftheseeingdisk,welistsizesofsemi-majorandsemi-
tends over∼1.0(cid:7)(cid:7)×1.0(cid:7)(cid:7) aroundthe peak of the continuumand
minoraxesthatarecorrectedfortheb(cid:2)roadeningofthePSFSPSF, [OIII]λ5007lineemission,correspondingto8kpcatz= 2.415.
Smaj,intrinsic, by setting Smaj,intrinsic = Sm2aj,obs−SP2SF alongthe The Hα surface brightness in this region is ΣHα ∼ (5−9) ×
same position angle. The same method was applied to the size 10−16ergs−1cm−2arcsec−2.
alongthesemi-minoraxis,whereresolved. Towardthesouthwest,thelineemissionbecomesfainter,but
Contours in Fig. 3 show the line-free continuum emission canbetracedoutoveranother2(cid:7)(cid:7),withatypical[OIII]λ5007sur-
for the galaxies where the continuum was detected. In most facebrightnessofΣ =(1−5)×10−16ergs−1 cm−2arcsec−2.
[OIII]
galaxiesthecontinuumisonlydetectedaftercollapsingtheline- The gas is more quiescent, with line widths of FWHM =
free cube along the wavelength axis. However, we detect rel- 300−400 kms−1. We show integrated spectra of both regions
atively bright continuum emission in NVSS J002431−303330 in Fig. 5. The box in the right panel of Fig. 3 shows the re-
and NVSS J201943−364542, which we need to subtract from gion from which we extracted the narrow-line emission. This
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Table2.Emission-linepropertiesoftheMRCR-SUMSSsources.
Source Line λ a λ b FWHMc Fluxd
0 obs
[Å] [Å] [kms−1] [10−16ergs−1cm−2]
NVSSJ002431−303330 Hβ 4861.3 16603.4±5.3 675±70 4.1±1.0
[OIII] 4958.9 16936.8±5.4 903±40 10.6±2.1
[OIII] 5006.9 17100.7±5.4 903±40 32.2±6.4
[NII] 6548.1 22364.6±7.1 220±25 1.6±0.3
Hα 6562.8 22414.8±7.1 675±70 12.9±2.6
Hα 6562.8 22414.8±7.1 3250±300 20.8±4.2
b
[NII] 6583.4 22485.1±7.1 220±25 4.8±1.0
NVSSJ004000−303333 [OII] 3727.5 16397.3±4.0 900±90 16.5±3.3
Hβe 4861.3 21385.6±3.7 744±70 5.8±1.2
[OIII] 4958.9 21814.9±3.8 744±70 22.3±4.5
[OIII] 5006.9 22026.1±3.8 744±70 67.5±13.5
NVSSJ004000−303333Bf [OIII] 4958.9 21794.0±3.8 760±80 1.3±0.7
south
[OIII] 5006.9 22005.0±3.8 760±80 3.9±1.9
south
NVSSJ012932−385433 Hβ 4861.3 15484.5±3.5 750±80 2.0±0.4
[OIII] 4958.9 15795.4±3.6 909±80 8.0±1.6
[OIII] 5006.9 15948.3±3.6 909±80 24.3±4.9
[NII] 6548.1 20857.4±4.7 1100±110 2.5±0.5
Hα 6562.8 20904.6±4.7 750±80 7.0±1.4
Hα 6562.8 20904.6±4.7 3500±350 20.1±4.0
b
[NII] 6583.4 20970.2±4.7 1100±110 7.4±1.5
[SII] 6716.4 21393.9±4.8 800±80 2.9±0.5
[SII] 6730.8 21439.8±4.8 800±80 3.1±0.5
NVSSJ030431−315308 Hβ 4861.3 15773.2±2.8 470±50 2.5±0.5
[OIII] 4958.9 16089.9±2.9 683±50 9.7±1.9
[OIII] 5006.9 16245.6±2.9 683±50 29.5±5.9
[NII] 6548.1 21246.3±3.8 910±90 2.3±0.5
Hα 6562.8 21294.0±3.8 470±50 5.7±1.1
[NII] 6583.4 21360.8±3.8 910±90 6.9±1.4
NVSSJ144932−385657 Hβ 4861.3 15310.4±3.4 350±35 1.1±0.2
[OIII] 4958.9 15617.8±3.5 420±40 6.4±1.3
[OIII] 5006.9 15769.0±3.5 420±40 19.5±3.9
[NII] 6548.1 20622.9±4.6 ≤200 0.5±0.1
Hα 6562.8 20669.2±4.6 350±35 6.6±1.3
[NII] 6583.4 20734.1±4.6 ≤200 1.4±0.3
NVSSJ201943−364542 Hβ 4861.3 15165.3±4.4 440±50 ≤0.5
[OIII] 4958.9 15469.8±4.5 540±30 1.5±0.3
[OIII] 5006.9 15619.5±4.5 540±30 4.5±0.9
[NII] 6548.1 20431.6±5.9 150±20 0.4±0.1
Hα 6562.8 20477.5±5.9 440±50 2.5±0.5
Hα 6562.8 20477.5±5.9 8250±800 35.9±7.0
b
[NII] 6583.4 20541.8±5.9 150±20 1.1±0.2
NVSSJ201943−36454Bg [OIII] 4958.9 15450.9±4.0 320±30 0.5±0.2
south
[OIII] 5006.9 15600.4±4.0 320±30 1.6±0.3
south
NVSSJ204601−335656 Hβ 4861.3 17010.6±5.5 840±80 1.1±0.2
[OIII] 4958.9 17352.1±5.7 820±80 3.4±0.7
[OIII] 5006.9 17520.0±5.7 820±80 10.2±2.0
[NII] 6548.1 22913.0±7.5 650±70 0.8±0.2
Hα 6562.8 22964.4±7.5 840±80 5.8±1.2
[NII] 6583.4 23036.5±7.5 650±70 2.4±0.5
NVSSJ234235−384526 [OII] 3727.5 16829.6±5.0 1100±110 7.7±1.5
Hβ 4861.3 21947.0±5.0 820±60 2.5±0.5
[OIII] 4958.9 22387.6±5.2 820±60 12.5±2.5
[OIII] 5006.9 22604.3±5.2 820±60 37.8±7.6
[OIII] 4958.9 22333.5±5.2 1330±130 5.6±1.1
blue
[OIII] 5006.9 22549.7±5.2 1330±130 16.9±3.4
blue
Notes.(a)Rest-framewavelength.(b)Observedwavelength.(c)Fullwidthathalfmaximum.(d)Integratedlineflux.(e)Commonfitwith[OIII]with
asingleredshiftandlinewidth.(f)Companionsource.Seetextfordetails.(g)Companionsource.Seetextfordetails.
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A&A586,A152(2016)
Table3.Emission-linepropertiesoftheCensorssources.
Source Line λ a λ b FWHMc Fluxd
0 obs
[Å] [Å] [kms−1] [10−16ergs−1cm−2]
CEN072 Hβ 4861.3 16662.1±4.0 518±70 7.3±1.6
[OIII] 4958.9 16989.8±4.0 612±40 7.7±1.5
[OIII] 5006.9 17161.1±4.0 612±40 23.3±4.5
[NII] 6548.1 22444.4±5.2 518±70 1.9±0.4
Hα 6562.8 22494.8±5.2 518±70 21.1±4.2
[NII] 6583.4 22565.4±5.2 518±70 5.8±1.2
CEN129 Hβe 4861.3 16637.0±4.0 1107±30 4.4±1.0
[OIII] 4958.9 16964.1±4.0 635±30 11.0±2.2
[OIII] 5006.9 17135.2±4.0 635±30 33.4±6.6
[NII] 6548.1 22408.6±5.2 1107±50 2.8±0.6
Hα 6562.8 22458.9±5.2 1107±50 12.7±2.5
[NII] 6583.4 22529.4±5.2 1107±50 8.4±1.6
CEN134 Hβf 4861.3 16307.9±1.9 230±60 2.3±0.4
[OIII] 4958.9 16635.4±1.9 330±60 11.0±2.2
[OIII] 5006.9 16796.4±1.9 330±60 33.2±6.6
[NII] 6548.1 21964.4±2.5 230±50 1.2±0.2
Hα 6562.8 22013.7±2.5 230±50 9.8±2.0
[NII] 6583.4 22082.8±2.5 230±50 3.7±0.7
Notes.(a) Rest-framewavelength.(b) Observedwavelength.(c) Fullwidthathalfmaximum, correctedforinstrumentalresolution.(d) Integrated
lineflux.(e)CommonfitwithHαwithasingleredshiftandlinewidth.(f)CommonfitwithHαwithasingleredshiftandlinewidth.
extended emission-line region to the southwest extends along z=2.185±0.001. The radio source is compact with a
theaxisbetweenthetworadiolobes. deconvolved size of 0.7(cid:7)(cid:7), and is associated with the optical
counterpart.
[OIII]λλ4959,5007 is brightin the H band. Hβ is detected
4.1.2. NVSSJ004000−303333
at5.6σ.Inthe K band,Hαand[NII]λλ6548,6583aredetected
NVSSJ004000−303333isadoubleradiosourcewithasizeof and strongly blended. Hα also shows a broad component with
17(cid:7)(cid:7) (Fig. 1). With SINFONI we find the [OIII]λλ4959,5007 FWHM ∼ 3500 km s−1. The [SII] doublet is clearly detected.
The two components are also strongly blended owing to their
doublet and Hβ in the K band at wavelengths that correspond
toz = 3.399±0.001.TheHαand[NII]λλ6548,6583linesfall intrinsicwidth(Fig.2).AlllinepropertiesarelistedinTable2.
The emission-line region is extended over 1.6(cid:7)(cid:7) × 1.2(cid:7)(cid:7).
outsidetheatmosphericwindows.Inthe H band,wedetectthe
It is brighter in the center with Σ ∼ (1.0−1.7) ×
[OII]λ3727doublet.The two lines of the doubletare too close Hα
10−15 ergs−1cm−2 arcsec−2 andfadestowardtheperiphery.We
toeachothertobespectrallyresolvedwithourdata(Fig.2).All
detectcontinuumemissioncoincidentwiththeemittinggas.The
linepropertiesarelistedinTable2.
Lineemissionextendsover2.5(cid:7)(cid:7) × 1.5(cid:7)(cid:7)withsurfacebright- [OIII]λ4959,5007 lines show a clear, relatively regular veloc-
nesses between Σ[Oiii] ∼ 5 × 10−16 erg s−1 cm−2 arcsec−2 and iatxyisg.raTdhieenltinoefsΔavre∼m3o5r0e knmarrso−w1 atloownagrda nthoerthseoaustth-esaosutt,hwweitsht
3×10−15ergs−1 cm−2 arcsec−2 (Fig.3).Faintcontinuumemis- FWHM ∼ 700−800 km s−1. In the northwest FWHMs are
sion is found associated with a knot to the very east of the higher,∼900−1000kms−1.
emission-lineregion,andabout1.5(cid:7)(cid:7)southwestfromthecenter,
outside the bright line emission. The K-band image of Bryant
etal.(2009a)showsaverysimilarcontinuummorphology,like- 4.1.4. NVSSJ030431−315308
wiseatlowsignal-to-noiseratio.
NVSSJ030431−315308isasingle,relativelycompactsourceat
Thelocalvelocitiesof[OIII]λ5007fallmonotonicallyfrom 9GHzand5.5GHz,withadeconvolvedsizeof1.8(cid:7)(cid:7)inourhigh-
the southwest to the northeast with a total gradient of about
300kms−1.Theknotinthefareastshowsanabruptvelocityin- est resolution data at 9 GHz (Fig. 1). The [OIII]λλ4959,5007
creaseof300kms−1 relativetothenearbyblueshiftedgas.The doubletis clearlydetectedin the H bandwith SINFONI andis
line widthsare lowerin the north(FWHM= 200−400kms−1) wellfittedwithsingleGaussians(Fig.2).Thesameholdsforthe
thaninthesouth(FWHM=700−1000kms−1). Hαand[NII]λλ6583lines.The[SII]doubletisnotdetected.All
linepropertiesarelistedinTable2.
AtfainterfluxlevelsthanshowninFig.3,butstillabove3σ,
Thelineemissionismarginallyspatiallyresolvedwithasize
wedetectanothersourceoflineemissionatadistanceofabout of1.5(cid:7)(cid:7)×1.5(cid:7)(cid:7),andaPSFwithFWHM =1.2(cid:7)(cid:7)×1.0(cid:7)(cid:7),thelargest
2(cid:7)(cid:7) to the south from the radio galaxy(about15 kpc at z ∼ 3).
in this program (Table B.1). Faint continuum emission is also
Theredshiftofthissecondsourceiszsouth = 3.395±0.001,i.e., detected,ataslightlydifferentposition(∼0.5(cid:7)(cid:7)tothewest)from
itisblueshiftedby350±90kms−1 relativetotheradiogalaxy.
thepeakin[OIII]λ5007surfacebrightness,butatthesamepo-
ThissourceisshowninFig.6andisdiscussedinSect.7.
sition as the peakof Hα surface brightness.The velocitymaps
showtwosmallredshifted(by50−100kms−1)regionsnorthand
4.1.3. NVSSJ012932−385433 southofthecontinuum,anduniformvelocitiesintherestofthe
source.Linewidthsarebetween500and1200kms−1andhigher
The SINFONI maps of NVSS J012932−385433 are shown inthewesternpartsoftheemission-lineregionassociatedwith
in Fig. 3. We find the optical emission lines at redshift thecontinuum.
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C.Colletetal.:Moderatelypowerfulhigh-zradiogalaxies
3e-15 250 1400
1 NNN 111000kkkpppccc 1 NNN 111000kkkpppccc 200 1 NNN 111000kkkpppccc 1200
EEE EEE 150 EEE
] 2e-15 100 1000
[arcsec 0 0 050 0 800
offset -1 1e-15 -1 --15000 -1 460000
-150
-2 -2 -200 -2 200
0 -250 0
-1 0 1 2 -1 0 1 2 -1 0 1 2
2 2 200 2 1200
NNN NNN NNN
111000kkkpppccc 3e-15 111000kkkpppccc 150 111000kkkpppccc 1000
EEE EEE EEE
1 1 1
100
] 800
[arcsec 0 2e-15 0 50 0 600
offset 1e-15 -050 400
-1 -1 -1
-100 200
-2 0 -2 -150 -2 0
-2 -1 0 1 2 -2 -1 0 1 2 -2 -1 0 1 2
2 3e-15 2 200 2 1600
NNN NNN NNN
111000kkkpppccc 111000kkkpppccc 150 111000kkkpppccc 1400
EEE EEE EEE
1 1 1 1200
100
] 2e-15
[arcsec 0 0 50 0 8100000
offset 1e-15 -050 600
-1 -1 -1 400
-100 200
-2 0 -2 -150 -2 0
-2 -1 0 1 2 -2 -1 0 1 2 -2 -1 0 1 2
2 2 150 2 1400
NNN NNN NNN
111000kkkpppccc 111000kkkpppccc 100 111000kkkpppccc 1200
EEE 2e-15 EEE EEE
1 1 1
50 1000
]
[arcsec 0 0 0 0 800
offset 1e-15 --15000 460000
-1 -1 -1
-150 200
-2 0 -2 -200 -2 0
-2 -1 0 1 2 -2 -1 0 1 2 -2 -1 0 1 2
400 800
2 NNN 111000kkkpppccc 8e-16 2 NNN 111000kkkpppccc 300 2 NNN 111000kkkpppccc 700
EEE EEE EEE
200 600
] 1 6e-16 1 1
offset[arcsec -10 4e-16 -10 -0110000 -10 345000000
-200 200
2e-16
-2 -2 -300 -2 100
0 -400 0
-2 -1 0 1 2 3 -2 -1 0 1 2 3 -2 -1 0 1 2 3
offset[arcsec] offset[arcsec] offset[arcsec]
Fig.3. Maps of [OIII] surface brightness (left), velocity (center), and FWHMline width (right) of our nine sources (from top to bottom). All
mapsare4(cid:7)(cid:7)×4(cid:7)(cid:7)wide,exceptforNVSSJ144932−385657andNVSSJ210626−314003,wheretheyare5(cid:7)(cid:7)×5(cid:7)(cid:7)wide.Thecircleinthebottomleft
representstheFWHMsizeoftheseeingdisk.Contoursmarkthecontinuumwheredetected.Continuumlevelsbeginat3σandthenincreasein
stepsof1σ.ThesolidblacklineinthevelocitymapsindicatestheaxisoftheradioemissionfromourATCAdata,orfromBrodericketal.(2007)
ifthesourceiscompact.Numbersgivehalfthelargestangularsizeinarcsec.
4.1.5. NVSSJ144932−385657 In the K band, Hα and [NII]λ6583 are narrow enough not to
be blended. FWHM = 350 km s−1 for Hα, and the width of
NVSSJ144932−385657hasoneofthelargestradiosourcesin
[NII]λ6583isdominatedbythespectralresolution.
our sample; the lobes are offset by 7.5(cid:7)(cid:7) relative to each other.
We find the [OIII] line at z = 2.149 ± 0.001. In the H band, NVSS J144932−385657 has a very extended emission-
we detect the [OIII]λλ4959,5007 doublet and Hβ (Fig. A.1). line region of nearly 4(cid:7)(cid:7) (∼30 kpc at z ∼ 2) along a
A152,page9of28
A&A586,A152(2016)
2 2 200 2 900
NNN NNN NNN 800
111000kkkpppccc 111000kkkpppccc 150 111000kkkpppccc
1 EEE 2e-15 1 EEE 1 EEE 700
ec] 100 600
arcs 0 0 50 0 500
offset[ 1e-15 0 340000
-1 -1 <0.7" -1 200
-50
CEN 072 100
-2 0 -2 -100 -2 0
-2 -1 0 1 2 -2 -1 0 1 2 -2 -1 0 1 2
2 4e-15 2 200 2 800
NNN NNN NNN
111000kkkpppccc 150 700
EEE EEE EEE
1 3e-15 1 100 1 600
ec] 50 500
[arcs 0 2e-15 0 2.5" 0 0 400
et
offs -50 300
-1 1e-15 -1 -100 -1 200
-150 100
CEN 129
-2 0 -2 -200 -2 0
-2 -1 0 1 2 -2 -1 0 1 2 -2 -1 0 1 2
2 2e-15 2 60 2 700
NNN NNN 40 NNN
600
EEE 1.6e-15 EEE 20 EEE
1 1 1
arcsec] 0 1.2e-15 0 --04200 0 450000
[
offset 8e-16 --8600 230000
-1 -1 -1
4e-16 9" -100
CEN 134 21. -120 100
-2 0 -2 -140 -2 0
-2 -1 0 1 2 -2 -1 0 1 2 -2 -1 0 1 2
offset[arcsec] offset[arcsec] offset[arcsec]
Fig.4.Mapsof[OIII]surfacebrightness(left),velocity(middle),andFWHMlinewidth(right)ofthethreesourcesfromtheCENSORSsample.
Allmapsare4(cid:7)(cid:7)×4(cid:7)(cid:7)oneachside.TheellipseinthebottomcornershowstheFWHMsizeoftheseeingdisk.Contoursmarkthestellarcontinuum
emission,detectedinthesamedatacube,beginningatthe3σlevelandincreasingbystepsof3σ.
1.4e−17 spectrum [OIII]5007 (a) 3e−17 [OIII]5007 (b)
fit
1.2e−17 nightskylines
2.5e−17
1e−17
−1Å) 8e−18 2e−17
−2 1.5e−17
m 6e−18 [OIII]4959 [OIII]4959
c
−1s 4e−18 1e−17
g Hβ
(er 2e−18 Hβ 5e−18
x
u
Fl 0 0
−2e−18 −5e−18
−4e−18 −1e−17
16400 16600 16800 17000 17200 17400 16400 16600 16800 17000 17200 17400
Wavelength(Å) Wavelength(Å)
Fig.5.Spectraextractedfromthesubregions ofNVSSJ002431−303330 showninFig.2.a)Spectrumfromthecontinuum region,withbroad
[OIII]lines(FWHM∼1150kms−1).b)Spectrumofthequiescentgas,withmuchmorenarrowlines(FWHM∼450kms−1).
northeast-southwest axis (Fig. 3). We identify two parts: a The velocity offset between the two regions is about
large, elongated region, which coincides with the continuum 800kms−1.Whilethecompactnortheasternparthasauniform
and extends over another 2(cid:7)(cid:7) toward the southwest, and a velocityfieldwitharedshiftofaboutv ∼ 400kms−1,thekine-
fainter,smallerregioninthenorthwest.Surfacebrightnessesof maticsintheveryextendedsouthwesternregionaremorecom-
[OIII]λ5007 are between 1 × 10−16 ergs−1cm−2arcsec−2 and plex with a maximum blueshift of about −400 kms−1, before
10 × 10−16 ergs−1cm−2arcsec−2. The northwestern region is thevelocitiesapproachthesystemicredshiftagainatthelargest
neartheedgeoftheSINFONIdatacube,anditisthereforepos- radii. Line widthsareFWHM = 200−500 kms−1 in the south-
siblethatitextendsfartherbeyondthefieldofviewofourdata. west,andupto800kms−1inthenortheast.Inthesouthwestern
Bothemission-lineregionsarealignedwiththeaxisoftheradio regionwefindelevatedwidthsinparticularnearthecontinuum
jet. andatabout1.5(cid:7)(cid:7),adistanceassociatedwiththesuddenvelocity
shiftfrom−400kms−1 tothesystemicvelocity.
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