The Herschel Comprehensive (U)LIRG Emission Survey (HerCULES): CO Ladders, fine structure lines, and neutral gas cooling

0.92 MB·English

by  M. J. F. Rosenberg

The Herschel Comprehensive (U)LIRG Emission Survey (HerCULES): CO
Ladders, fine structure lines, and neutral gas cooling 1
M.J.F.Rosenberg1,P.P.vanderWerf1,S.Aalto2,L.Armus3,V.Charmandaris4,23,24,T.
5 D´ıaz-Santos3,A.S.Evans5,22 J.Fischer6,Y.Gao7,E.Gonza´lez-Alfonso8,T.R.Greve9,A.I.
1 Harris10,C.Henkel11,26,F.P.Israel1,K.G.Isaak12,C.Kramer13,R.Meijerink1,D.A.Naylor14,
0
D.B.Sanders15,H.A.Smith16,M.Spaans17,L.Spinoglio18,G.J.Stacey19,I.Veenendaal14,S.
2
Veilleux10,25,F.Walter20,A.Weiß11,M.C.Wiedner24,M.H.D.vanderWiel14,E.M.Xilouris4
n
a
J

3
1
ABSTRACT

]
A (Ultra) Luminous Infrared Galaxies ((U)LIRGs) are objects characterized by their extreme infrared
(8-1000 µm) luminosities (L > 1011L and L > 1012 L ). The Herschel Comprehensive
G LIRG (cid:12) ULIRG (cid:12)
ULIRG Emission Survey (HerCULES; PI van der Werf) presents a representative flux-limited sample
.
h of29(U)LIRGsthatspansthefullluminosityrangeoftheseobjects(1011 ≤ L ≥ 1013). WiththeHer-
(cid:12)
p
schel Space Observatory, we observe [CII] 157 µm, [OI] 63 µm, and [OI] 145 µm line emission with
o- PACS,COJ=4-3throughJ=13-12,[CI]370µm,and[CI]609µmwithSPIRE,andlow-JCOtransitions
r with ground-based telescopes. The CO ladders of the sample are separated into three classes based on
t
s theirexcitationlevel. In13ofthegalaxies,the[OI]63µmemissionlineisselfabsorbed. Comparingthe
a COexcitationtotheIRAS60/100µmratioandtofarinfraredluminosity,wefindthattheCOexcitation
[
is more correlated to the far infrared colors. We present cooling budgets for the galaxies and find fine-

1 structure line flux deficits in the [CII], [SiII], [OI], and [CI] lines in the objects with the highest far IR
v
fluxes,butdonotobservethisforCO4 ≤ J ≤ 13. Inordertostudytheheatingofthemoleculargas,
5 upp
we present a combination of three diagnostic quantities to help determine the dominant heating source.
8
9 Using the CO excitation, the CO J=1-0 linewidth, and the AGN contribution, we conclude that galax-
2 ieswithlargeCOlinewidthsalwayshavehigh-excitationCOladders,andoftenlowAGNcontributions,
0 suggestingthatmechanicalheatingisimportant.
.
1
Subjectheadings:
0
5
1
: 1LeidenObservatory, LeidenUniversity, P.O.Box9513, 2300 don,GowerStreet,LondonWC1E6BT,UK
v RALeiden,TheNetherlands 10Department of Astronomy, University of Maryland, College
Xi 2DepartmentofEarthandSpaceSciences,ChalmersUniversity Park,MD20742,USA
ofTechnology,OnsalaObservatory,43994Onsala,Sweden 11Max-Planck-Institutfu¨rRadioastronomie,AufdemHu¨gel16,
ar 3SpitzerScienceCenter,CaliforniaInstituteofTechnology,MS Bonn,D-53121,Germany
220-6,Pasadena,CA91125,USA 12Scientific Support Office, ESTEC/SRE-S,Keplerlaan 1, NL-
4Institute for Astronomy, Astrophysics, Space Applications & 2201AZ,Noordwijk,TheNetherlands
RemoteSensing,NationalObservatoryofAthens,P.Penteli,15236 13Instituto Radioastronom´ıa Milime´trica (IRAM), Av. Divina
Athens,Greece
Pastora7,NucleoCentral,18012Granada,Spain
5Department of Astronomy, University of Virginia, P.O. Box 14InstituteforSpaceImagingScience,DepartmentofPhysicsand
400325,Charlottesville,VA22904,USA
Astronomy,UniversityofLethbridge,Lethbridge,AB,Canada
6Naval Research Laboratory, Remote Sensing Division, 4555 15InstituteforAstronomy,2680WoodlawnDrive,Universityof
OverlookAveSW,Washington,DC20375,USA
Hawaii,Honolulu,HI96822
7Purple Mountain Observatory, Chinese Academy of Sciences 16Harvard-Smithsonian Center for Astrohpysics, 60 Garden
(CAS),2WestBeijingRoad,Nanjing210008,China
Street,Cambridge,MA02138,USA
8UniversidaddeAlcala´,DepartamentodeFsicayMatema´ticas, 17Kapteyn Astronomical Institute, P.O. Box 800, NL-9700 AV
CampusUniversitario,28871Alcala´deHenares,Madrid,Spain
Groningen,TheNetherlands
9DepartmentofPhysicsandAstronomy,UniversityCollegeLon-
1
1. Introduction 1996; Veilleux et al. 2002). Regardless of the vari-
ousheatingprocessesavailable,however,theluminos-
(Ultra)LuminousInfraredGalaxies((U)LIRGs)in
ity of most local (U)LIRGs seem to be energetically
the local universe are remarkable galaxies exhibiting
driven by starbursts (Genzel et al. 1998; Downes &
an extremely high infrared luminosity, L >
8−1000µm Solomon 1998; Veilleux et al. 1999, 2002; Gao &
1011L for LIRGs and L > 1012L for
(cid:12) 8−1000µm (cid:12) Solomon 2004; Veilleux et al. 2009). (U)LIRGs are
ULIRGs. Luminousinfraredgalaxieswerefirstiden-
alsothoughttorepresentthetransitionalphaseinevo-
tified in large numbers with observations from the lution from a starburst galaxy to elliptical/lenticular
InfraRed Astronomical Satellite (IRAS), which was
galaxies(Sandersetal.1988b;Genzeletal.2001;Tac-
launched in 1983 (Houck et al. 1985). After the dis-
coni et al. 2002; Rothberg & Fischer 2010; Rothberg
coverythattheseobjectsallcontainmassiveamounts
etal.2013),andthusmustquenchtheirstarformation
ofmoleculargas(Sandersetal.1988a;Veilleuxetal.
duringthisperiod. Infact,someevidenceforthiswas
2002), detailed studies of the spectroscopic cooling
foundinthediscoveryofmassivemolecularoutflows
lines were carried out with the Infrared Space Ob- with the Herschel Space Observatory (Fischer et al.
servatory(ISO;Malhotraetal.(1997);Luhmanetal.
2010; Sturm et al. 2011; Spoon et al. 2013; Veilleux
(1998); Helou et al. (2001); Malhotra et al. (2001);
etal.2013;Gonza´lez-Alfonsoetal.2014)aswellasas
Luhman et al. (2003); Abel et al. (2009)), ground
byground-basedtelescopes(e.g.,Feruglioetal.2010;
based observations of [CI] (Gerin & Phillips 1998,
Weißetal.2012).
2000), Spitzer Space Telescope (Armus et al. 2009;
Since (U)LIRGs offer a unique insight into this
D´ıaz-Santos et al. 2011; Stierwalt et al. 2013) and
transitional phase from star-forming to quiescent
the Herschel Space Observatory (Gracia´-Carpio et al.
galaxies,understandingwhichmechanismsareaffect-
2011; D´ıaz-Santos et al. 2013; Farrah et al. 2013; Lu
ing the star-forming gas is crucial. Many studies of
etal.2014;D´ıaz-Santosetal.2014). Inthelocaluni-
the star forming gas in (U)LIRGs have been made
verse ULIRGs are rare (Soifer & Neugebauer 1991),
since its universal presence in (U)LIRGs was deter-
but at higher redshifts (z > 1) they represent most of
mined(Sandersetal.1991;Sanders&Mirabel1996;
thecosmicinfraredbackgroundandarethedominant
Solomon et al. 1997). In general, gas is heated by
sourceofstarformationuptoz=2(Caputietal.2007;
either radiation (i.e. UV photons, X-ray photons),
Magnelli et al. 2011; Berta et al. 2011a,b; Magnelli
energetic particles (cosmic rays) or mechanical pro-
et al. 2013; Gruppioni et al. 2013). Locally, these
cesses(i.e. turbulence, stellarwinds, outflows, super-
objects are hosts to intense starbursts, and/or active
novae). The interplay between these heating sources
galactic nuclei (AGN), and often are part of a merg-
can account for the extreme environments found in
ing galaxy group (Armus et al. 1987; Sanders et al.
(U)LIRGs, in comparison to less intense star form-
1988b;Barnes&Hernquist1992;Sanders&Mirabel
ingenvironments(Aaltoetal.1991,1995a). Thehigh
amountofenergyinjectedintothegasinthesegalaxies
18IstitutodiAstrosicaePlanetologiaSpaziali,INAF,ViaFosso
is displayed by emission lines that serve as a coolant
delCavaliere100,I-00133Roma,Italy
alongwithinfrareddustemission. Theemissionlines
19Department of Astronomy, Cornell University, Ithaca, NY
14853,USA responsible for most of the gas cooling are the [CII]
20Max-PlanckInstitutfurAstronomie, Ko¨nigstuhl17, D-69117 lineat157µm(2P3/2 −2 P1/2),the[OI]lineat63µm
Heidelberg,Germany (3P −3 P ),andCO(rotationaltransitions). TheHer-
1 2
22NationalRadioAstronomyObservatory,520EdgemontRoad, schel Space Observatory has, for the first time, pro-
Charlottesville,VA22903,USA
vided astronomers with simultaneous access to these
23UniversityofCrete,DepartmentofPhysics,Heraklion71003,
important far infrared cooling lines and the CO rota-
Greece
tionalladder(COladder)in(U)LIRGs.Usingthemul-
24ObservatoiredeParis, LERMA,61AvenuedelObservatoire,
75014Paris,France tiple rotational transitions of CO from J=1-0 through
25JointSpace-ScienceInstitute,UniversityofMaryland,College J=13-12, the density, temperature, column density,
Park,MD20742 and mass (with the addition of 13CO) can be esti-
26AstronomyDepartment,KingAbdulazizUniversity,P.O.Box mated(eg.Rangwalaetal.2011;Spinoglioetal.2012;
80203,Jeddah21589,SaudiArabia
Rigopoulouetal.2013;Papadopoulosetal.2014). In
1HerschelisanESAspaceobservatorywithscienceinstruments
some cases, it is possible to even discern specifically
providedbyEuropean-ledPrincipalInvestigatorconsortiaandwith
importantparticipationfromNASA. the heating mechanism (Loenen et al. 2008; Hailey-
2
Dunsheathetal.2008;vanderWerfetal.2010a;Mei- arangeofobjectsincludingstarburstgalaxies,AGNs,
jerink et al. 2013; Lu et al. 2014; Rosenberg et al. and composite sources, and covering also a range of
2014a;Pereira-Santaellaetal.2014). IRAS 60/100 micron ratios. The full list of included
Inthispaper,weintroduceobservationsofallmajor galaxies and their respective properties can be found
neutralgascoolinglineofarepresentativesample,the inTable1. Theinfraredluminosityandtheluminosity
HerCULES sample, of local (U)LIRGs spanning the distancearefromArmusetal.(2009).
luminosityrangefrom1011 <L < 1013 L . InSec- InordertoobtainacomprehensiveviewoftheCO
FIR (cid:12)
tion 2, we present the HerCULES sample and obser- emission and the cooling budget of these galaxies,
vationsfromtheHerschel/SPIREandHerschel/PACS we proposed Herschel/SPIRE spectroscopy (for the
spectrometers, which include [CII], [OI] 63µm, [OI] CO ladder) and Herschel/PACS spectroscopy (for the
145µm,CO(4≤ J <13),and[CI]370µmand609 [CII] and [OI] fine structure lines) of the entire sam-
upp
µm,usingthecosmologicalparametersH =70kms−1 ple, unless PACS observations were already observed
0
Mpc,Ω =0.72,andΩ =0.28.Inthispaperwe as part of another program. In addition to the galax-
vaccum matter
focusonthemainneutralgascoolinglines. Wethere- ies observed for HerCULES, we have included NGC
foredonotanalyzethe[NII]lines,whichariseinion- 4418,NGC1068,andArp220forcompleteness. This
ized gas, orother molecular lines whichdo not affect projectwasapprovedasaKeyProjectontheHerschel
the thermal balance. Specifically, we do not discuss SpaceObservatory,underthenameHerschelCompre-
H O since in the cases where these lines are bright, hensive (U)LIRGEmission Survey(HerCULES -P.I.
2
there is strong evidence that they are radiatively ex- VanderWerf). KeyelementsofHerCULESare:
cited(Gonza´lez-Alfonsoetal.2010;vanderWerfetal.
2011;Yangetal.2013)anddonotremovekineticen- • a representative flux-limited sample of local
ergy from the gas and thus do not contribute to the LIRGsandULIRGs;
cooling. We show spectra for three sample galaxies
• comprehensive coverage of the SPIRE spectral
thatrepresentthreedifferentclassesofexcitation,and
range at the highest spectral resolution mode
theCOladdersforthefullsampleinSection3. Using
(covering the CO ladder, [CI] and [NII] fine
the full sample, in Section 4 we analyze the gas ex-
structure lines, and any other bright features
citation, coolingbudgetofthesample, andadiagram
suchasH Olines);
fordeterminingadditionalheatingmechanismsforthe 2
gas. OurconclusionsarepresentedinSection5. • comprehensivecoverageofthekeyfine-structure
coolinglines[CII]and[OI]withPACSobserva-
2. Observations tions;
2.1. TheHerCULESsample
Details about the galaxy type and observation ID
can be seen in Table 1. We have included ob-
The sample was chosen from the IRAS Revised
servations from other programs (KPGT esturm 1K,
BrightGalaxySample(RBGS),whichcontainsall629
KPGT cwilso01 1, OT1 larmus 1, OT1 shaileyd 1)
extragalactic sources with IRAS 60 µm flux density
tohelprealizethecompleteflux-limitedsample. The
S > 5.24 Jy in the (IRAS-covered) sky at Galac-
60
referencesfortheseobservationsarealsoinTable1.
tic latitudes |b| > 5 (Sanders et al. 2003). From the
IRAS RBGS we select a sub-sample applying limits
2.2. Herschel/SPIREobservations
both in S and L : at luminosities : L > 1012 L
60 IR IR (cid:12)
(ULIRGs), all sources with S60 > 11.65 Jy are in- SpectrawereobtainedwiththeSpectralandPhoto-
cluded, while at luminosities 1011 L(cid:12) < LIR < 1012 metricImagingReceiverandFourier-TransformSpec-
L(cid:12) (LIRGs), sources with S60 > 16.4 Jy are in- trometer(SPIRE-FTS,Griffinetal.2010)onboardthe
cluded. From this flux-limited representative parent Herschel Space Observatory (Pilbratt et al. 2010) for
sample of 32 targets, we removed three LIRGs for the full HerCULES sample. The observations were
whichnoground-basedCOdataareavailable,withthe carriedoutinstaringmodewiththegalaxynucleuson
exception of ESO 173-G015, IRAS 13120-5453, and thecentralpixelofthedetectorarray,withabeamsize
MCG+12-02-001. The resulting representative flux- varyingfrom17”-42”fortheCOtransitions. Thehigh
limited sample consists of 21 LIRGs and 8 ULIRGs. spectralresolutionmodewasusedwitharesolutionof
The sample covers a factor of 32 in L and contains
IR
3
1.2 GHz over the two observing bands. The low fre- over different source sizes until it finds one that pro-
quencyfocalplanearray(LongWavelengthSpectrom- videsagoodmatchintheoverlaprangeofthetwoob-
eterArray,SLW)coversν=447-989GHz(λ=671-303 servingbandsnear1000GHz,andisfurtherdiscussed
µm) and the high frequency focal plane array (Short in Wu et al. (2013). We set the Gaussian reference
WavelengthSpectrometerArray,SSW)coversν=958- beamto42”,thelargestSPIREbeamsize. Thebeam-
1545GHz(λ=313-194µm),andtogethertheyinclude sizecorrectedfluxvaluesforthe10extendedsources
theCOJ =4−3toCOJ =13−12lines. Forgalaxies arelistedinTable2, alongwiththecompactsources.
with z > 0.03, the rest frequency of the J=4-3 tran- Wenotethattheerrorintheextendedsourcefluxcor-
sition falls short of the SPIRE coverage. All galaxies rectioncouldbesignificantduetotheassumptionsthat
were observed in the sparse observing mode besides the high-J CO transitions are distributed in the same
NGC 4418, which was observed in the intermediate wayasthethelow-JCOlines.Ifhigh-JCOtransitions
mode. are only coming from a centralized compact region,
The data were reduced using version 13.0 of the weareoverestimatingtheirfluxwithourbeamcorrec-
Herschel Interactive Processing Environment (HIPE). tion method. For this reason, we apply an additional
Initial processing steps included timeline deglitching, 15% error to the extended galaxies. There are three
linearitycorrection,clippingofsaturatedpoints,time- targetsinthesamplethathavemultiplepointings;Arp
domain phase correction, and inteferogram baseline 299, NGC 1365, and NGC 2146. In the case of Arp
subtraction. After a second deglitching step and in- 299,weuseonlythepointingforArp299A.ForNGC
terferogramphasecorrection,theinterferogramswere 1365 we take the average of the northeast and south-
Fourier transformed, and the thermal emission from west pointings. This is done since the northeast and
instrumentandtelescopewasremovedfromtheresult- southwest pointings have approximately a 50% over-
ingspectra. Theaveragedspectrawerefluxcalibrated lap in field of view at the center of the galaxy. This
as point sources using the calibration tree associated overlapregionisthecenterofthePACSobservations,
withHIPE13.0. Followingthesestepsa”dark”spec- so for comparison, it is best to average the northeast
trumwassubtracted,toremoveanyresidualemission andsouthwestpointings. ForNGC2146,weuseonly
fromthetelescopeandtheinstrument. Sincetheemis- thenuclearpointing.
sionofmostofoursourcesiscontainedentirelyinthe CO and [CI] line fluxes were extracted using ver-
centralpixelofthedetectorarrays,a”dark”spectrum sion 1.92 of FTFitter2, a program specifically created
was constructed by spectrally smoothing a combina- to extract line fluxes from Fourier transform spectro-
tion of several off-axis pixels. For extended targets, graphs, and are listed in Table 2. This is an interac-
where the off-axis pixels contain emission, the dark tive data language (IDL) based graphical user inter-
was obtained from a deep blank-sky observation ob- face, that allows the user to fit lines, choose line pro-
tained on the same observing day. We compared the files, fix any line parameter, and extract the flux. We
two methods and found no differences, but the noise defineathirdorderpolynomialbaselinetofitthecon-
was smaller using the smooth off axis pixels, in the tinuum for the SLW and SSW separately and derive
caseofthecompacttargets. theintegratedlineintensitiesfrombaselinesubtracted
For all extended sources (Arp 299, ESO 173- spectra with a simultaneous line fit of all CO, [CI],
G015,MCG+12–02–001, Mrk 331, NGC 1068, NGC [NII] and other bright lines in the spectrum. We use
1365, NGC 2146, NGC 3256, NGC 5135, and NGC aGaussianlineprofile,whichisbasedontheassumed
7771),anaperturecorrectionisnecessarytocompen- intrinsic line shape with a width derived from spec-
sateforthewavelengthdependentbeamsize(Makiwa trallyresolvedCO1-0,convolvedwiththeinstrumen-
et al. 2013). We defined a source as extended using tallineshape,whichisaSincprofile. Weadoptaner-
LABOCA or SCUBA 350 or 450 µm (respectively) rorof16%forthenon-extendedgalaxyfluxes,which
mapswith8”resolution. Weconvolvedthe8”resolu- encompasses our dominant sources of error, 10% for
tion maps with the SPIRE FTS resolution, and if the the flux extraction and baseline definition and 6% for
galaxy was more extended than the smallest SPIRE the absolute calibration uncertainty for staring-mode
beam size, we defined it as extended. In order to SPIRE FTS observations (Swinyard et al. 2014). For
correct for the extended nature of these sources, we thecaseofextendedsources,weadoptasalreadymen-
employ HIPE’s semiExtendedCorrector tool (SECT).
Thistool’derives’anintrinsicsourcesizebyiterating 2https://www.uleth.ca/phy/naylor/index.php?page=ftfitter
4
tioned, an additional 15% error from the beam size
corrections, resulting in a total error 30% for the 10
extendedsources.
5
Table1
SampleProperties
1 2 3 4 5 6 7 8 9 10 11
NGC34 11.49 0.78 0.01962 84.1 330 SB [OI]63,[OI]145,[CII] 00h11m06.67s-12°06’26.13” 1342199416 KPOTpvanderw1
(IRAS00085-1223) 194−671µm 00h11m06.53s-12°06’24.90” 1342199253 KPOTpvanderw1
MCG+12–02–001 11.50 1.07 0.01570 69.8 200 SB [OI]63,[OI]145,[CII] 00h54m03.33s+73°04’59.83” 1342193211 KPOTpvanderw1
(IRAS00506+7248) 194−671µm 00h54m03.56s+73°05’10.38” 1342213377 KPOTpvanderw1
IC1623 11.71 1.14 0.02007 85.5 250 SB,AGN [OI]63,[OI]145,[CII] 01h07m46.59s-17°30’26.46” 1342212532 KPOTpvanderw1
(IRAS01053-1746) 194−671µm 01h07m46.74s-17°30’26.05” 1342212314 KPOTpvanderw1
NGC1068 11.40 9.07 0.003793 15.9 300 AGN,SB [OI]63 02h42m40.78s-00°00’47.16” 1342191153 KPGTesturm1K
(IRAS02401-0013) [OI]145,[CII] 02h42m40.73s-00°00’42.24” 1342191154 KPGTesturm1K
194−671µm 02h42m40.92s-00°00’46.65” 1342213445 KPGTcwilso011
NGC1365 11.00 4.32 0.00546 17.9 250 Sy1,SB [OI]63 03h33m36.31s-36°08’16.61” 1342191295 KPGTesturm1K
(IRAS03317-3618) [OI]145,[CII] 03h33m36.26s-36°08’24.33” 1342191294 KPGTesturm1K
194−671µm 03h33m36.48s-36°08’19.32” 1342204020 KPOTpvanderw1
NGC1614 11.65 1.50 0.01594 67.8 220 SB [OI]63,[OI]145,[CII] 04h33m59.79s-08°34’44.19” 1342190367 KPOTpvanderw1
(IRAS04315-0840) 194−671µm 04h33m59.85s-08°34’44.15” 1342192831 KPOTpvanderw1
IRASF05189–2524 12.16 0.60 0.04256 187 300 QSO [OI]63 05h21m01.24s-25°21’43.16” 1342219441 KPGTesturm1K
[OI]145,[CII] 05h21m01.28s-25°21’42.15” 1342219442 KPGTesturm1K
194−671µm 05h21m01.42s-25°21’45.47” 1342192832a KPOTpvanderw1
194−671µm 05h21m01.42s-25°21’45.48” 1342192833a KPOTpvanderw1
NGC2146 11.12 6.97 0.00298 17.5 250 SB [OI]63,[OI]145,[CII] 06h18m35.53s+78°21’25.39” 1342193210 KPOTpvanderw1
(IRAS06106+7822) 194−671µm 06h18m38.07s+78°21’25.06” 1342204025 KPOTpvanderw1
NGC2623 11.60 1.15 0.01851 84.1 400 SB,AGN [OI]63,[OI]145,[CII] 08h38m24.29s+25°45’16.72” 1342208904 KPOTpvanderw1
(IRAS08354+2555) 194−671µm 08h38m24.14s+25°45’17.34” 1342219553 KPOTpvanderw1
NGC3256 11.64 4.61 0.00935 38.9 230 SB [OI]63 10h27m51.61s-43°54’15.39” 1342210383 KPGTesturm1K
(IRAS10257-4338) [OI]145,[CII] 10h27m51.45s-43°54’21.87” 1342210384 KPGTesturm1K
194−671µm 10h27m51.49s-43°54’16.00” 1342201201 KPOTpvanderw1
Arp299A 11.93 4.84 0.01030 50.7 325 SB,AGN [OI]63 11h28m33.41s+58°33’46.04” 1342199421 KPGTesturm1K
IC694 [OI]145 11h28m33.41s+58°33’46.04” 1342232602 OT1shaileyd1
(IRAS11257+5850) [CII] 11h28m33.41s+58°33’46.04” 1342208906 KPGTesturm1K
194−671µm 11h28m33.41s+58°33’46.04” 1342199248 KPOTpvanderw1
ESO320–G030 11.17 1.67 0.01078 41.2 350 SB [OI]63,[OI]145,[CII] 11h53m11.75s-39°07’51.75” 1342212227 KPOTpvanderw1
(IRAS11506–3851) 194−671µm 11h53m11.52s-39°07’50.24” 1342210861 KPOTpvanderw1
NGC4418 11.19 1.74 0.007268 36.5 163 Sy2 [OI]63 12h26m54.51s-00°52’40.77” 1342187780 KPGTesturm1K
(IRAS12243-0036) [OI]145,[CII] 12h26m54.57s-00°52’36.93” 1342210830 KPGTesturm1K
194−671µm 12h26m54.60s-00°52’36.54” 1342210848 KPGTesturm1K
Mrk231 12.57 1.48 0.04217 192 200 QSO [OI]63 12h56m14.65s+56°52’24.13” 1342189280 KPGTesturm1K
(IRAS12540+5708) [OI]145,[CII] 12h56m14.29s+56°52’23.40” 1342186811 SDPesturm3
194−671µm 12h56m14.29s+56°52’26.73” 1342210493 KPOTpvanderw1
IRAS13120–5453 12.32 1.94 0.03076 144 400 Sy2,SB [OI]63 13h15m06.28s-55°09’24.46” 1342214628 KPGTesturm1K
[OI]145,[CII] 13h15m06.17s-55°09’25.38” 1342214629 KPGTesturm1K
194−671µm 13h15m06.11s-55°09’23.21” 1342212342 KPOTpvanderw1
Arp193 11.73 8.19 0.02330 110 400 SB,L [OI]63,[OI]145,[CII] 13h20m35.20s+34°08’24.58” 1342197801 KPOTpvanderw1
(IRAS13183+3423) 194−671µm 13h20m35.35s+34°08’23.46” 1342209853 KPOTpvanderw1
NGC5135 11.30 0.91 0.01369 60.9 150 Sy2,SB [OI]63,[OI]145,[CII] 13h25m43.96s-29°50’01.74” 1342190371 KPOTpvanderw1
(IRAS13229-2934) 194−671µm 13h25m43.91s-29°50’00.27” 1342212344 KPOTpvanderw1
ESO173–G015 11.38 3.61 0.00974 34 200 SB [OI]63,[OI]145,[CII] 13h27m24.00s-57°29’23.63” 1342190368 KPOTpvanderw1
(IRAS13242–5713) 194−671µm 13h27m23.95s-57°29’22.89” 1342202268 KPOTpvanderw1
Mrk273 12.21 1.05 0.03736 173 520 SB,Sy2 [OI]63 13h44m42.09s+55°53’09.14” 1342207801 KPGTesturm1K
(IRAS13428+5608) [OI]145,[CII] 13h44m41.82s+55°53’08.75” 1342207802 KPGTesturm1K
194−671µm 13h44m42.10s+55°53’10.50” 1342209850 KPOTpvanderw1
Zw049.057 11.35 1.05 0.01300 65.4 200 SB [OI]63,[OI]145,[CII] 15h13m13.18s+07°13’30.71” 1342190374 KPOTpvanderw1
CGCG049-057 194−671µm 15h13m13.10s+07°13’29.19” 1342212346 KPOTpvanderw1
(IRAS15107+0724)
Arp220 12.28 4.87 0.01813 77 504 SB,AGN [OI]63,[OI]145 15h34m57.22s+23°30’11.06” 1342191304 KPGTesturm1K
(IRAS15327+2340) [CII] 15h34m57.21s+23°30’10.13” 1342191306 KPGTesturm1K
194−671µm 15h34m57.11s+23°30’11.26” 1342190674 KPGTcwilso011
NGC6240 11.93 1.10 0.02448 116 500 SB,AGN [OI]63 16h52m59.10s+02°24’03.58” 1342216622 KPGTesturm1K
(IRAS16504+0228) [OI]145,[CII] 16h52m59.10s+02°24’02.79” 1342216623 KPGTesturm1K
194−671µm 16h52m59.01s+02°24’03.27” 1342214831 KPOTpvanderw1
IRASF17207–0014 12.46 1.56 0.04281 198 620 SB,L [OI]63 17h23m21.83s-00°16’59.82” 1342229692 KPGTesturm1K
6
2.3. Herschel/PACSobservations tral resolution of PACS at 145 µm is more than suffi-
cient to resolve the ∼ 0.2 µm separation between the
We have obtained observations of the [OI] 63 µm
two peaks in the [OI] profile (Figure 1). Therefore,
([OI] ), [OI] 145 µm ([OI] ), and [CII] 157 µm 63
63 145 we conclude that this double-peaked profile is due to
emission lines with the Integral Field Spectrometer
absorption in the center of the profile by colder fore-
of the Photodetector Array Camera and Spectrometer
ground gas. We note that [OI] absorption is due to
(PACS,Poglitschetal.2010)onboardHerschelSpace 63
O in the ground state while absorption at 145µm re-
Observatory for every object in the HerCULES sam-
quires O to be at a state having an energy of 226 K
ple. Thedatapresentedherewereobtainedaspartof
above the ground state. Therefore, in cool or moder-
the Herschel program KPOT pvanderw 1 (PI: P. van
ate density gas the [OI] line will not show an ab-
der Werf), complemented by observations from other 145
sorption feature, even if the [OI] line does. This
programs. The observations and program IDs of the 63
same effect has been noted in Arp 220, which shows
[CII]and[OI]linesarelistedinTable1.
the [OI] in full absorption (Gonza´lez-Alfonso et al.
63
The data were downloaded from the Herschel Sci-
2012). InthecaseofNGC4418andZw049.057,the
ence Archive and processed using HIPE v11.0. Stan-
[OI] line has an inverse P Cygni profile, suggesting
63
dard processing steps including timeline deglitching,
that the absorbing foreground gas is flowing into the
application of the Relative Spectral Response Func-
nuclearregion. Thethreeexamplegalaxiesforwhich
tion and detector flat fielding, and subtraction of the
the spectra are shown in Figures 1-3 display increas-
on and off chop positions, gridding along the spec-
ing absorption of the [OI] µm line. In NGC 7552,
63
tral axis, and combination of the nod positions. With
a face-on starburst galaxy, the profile remains Gaus-
the exception of Arp 299, the objects are all centered
sian,whileinMrk331,alate-stagemerger,thereisa
on the 9(cid:48).(cid:48)4 central spaxel of the 5 by 5 PACS array,
strongdipinthemiddleoftheprofile. IRASF17207–
observed in staring mode. The fluxes are extracted
0014 is known for being one of the coolest ULIRGs,
from the central spaxel, using the extractSpaxelSpec-
hereabsorptiondominatesthe[OI] emission.Forthe
63
trum routine, and referenced to a point source. We
[OI] profiles that show an absorption feature, we fit
63
use the pointSourceLossCorrection routine to capture
the Gaussian only to the wings of the emission pro-
any additional flux that may not be captured in the
file and state the flux in parentheses. The Gaussian-
central spaxel. Finally, version 3.10 of SPLAT as
fit flux is only valid if the true line profile is Gaus-
part of the STARLINK software package (http://star-
sian. Wesuggestthisisamorerobustestimateofthe
www.dur.ac.uk/∼pdraper/splat/splat-vo/) was used to
true integrated flux of the [OI] line emerging from
63
subtract the baseline from each observation, and iso-
thewarmnuclearregion,sinceinmanycases,theab-
latethedesiredlines,inthecaseofPACSrangespec-
sorption dominates the profile. We note that using a
troscopy. Thereductionstepswerethesameforboth
Gaussian profile to extrapolate the line flux requires
the PACS range and line spectroscopy, two different
an assumption that the location of the line center (a
observingmodesofPACS.
free parameter) is in the middle of the profile, which
Arp299wasobservedinthemappingmodeandre- may not be accurate, especially in the case of IRAS
ducedusingthestandardpipelinereduction. Theinte- F17207–0014,oranyothergalaxieswithanasymmet-
gratedfluxforArp299A(presentedinthispaper)was riclineprofile. Wehavetestedtherelationspresented
calculatedbysummingthefluxwithina25”aperture in the rest of this paper with both the integrated flux
centeredonArp299ASPIREpointing. and the Gaussian fit, and find it does not strongly af-
In order to extract the line parameters from the fecttheresults. Boththeobservedlinefluxesandthe
PACSobservations,wefirstintegrateoverthebaseline gaussian-fit line fluxes, stated in the parentheses, are
subtracted spectrum and then we fit a Gaussian pro- alsopresentedinTable2.
file to the baseline subtracted flux. In some sources,
the [OI] line shows a double-peaked profile, where 3. Results
63
thefluxatthecentralwavelengthisdiminished,which
3.1. Spectraandlinefluxes
could indicate Keplerian rotation. However, if this
were the case, then we would expect a similar pro- AllSPIRECOand[CI]linefluxesarelistedinTa-
fileinthe[OI]145µmlineandpossiblytheotherfine ble2.Wepresentthreeexamplesofgalaxyspectraob-
structure lines as well, which is not seen. The spec- tainedwithSPIREinthetoppanelsofFigure1,2,and
7
Table1—Continued
1 2 3 4 5 6 7 8 9 10 11
[OI]145,[CII] 17h23m31.84s-00°16’57.60” 1342229693 KPGTesturm1K
194−671µm 17h23m21.93s-00°17’01.10” 1342192829 KPOTpvanderw1
IRASF18293–3413 11.88 1.82 0.01817 86 270 [OI]63,[OI]145,[CII] 18h32m41.34s-34°11’36.90” 1342192112 KPOTpvanderw
194−671µm 18h32m41.17s-34°11’27.23” 1342192830 KPOTpvanderw1
IC4687/6 11.62 0.84 0.01735 81.9 230 SB [OI]63 18h13m39.94s-57°43’49.66” 1342239740 OT1larmus1
(IRAS18093-5744) [CII] 18h13m39.80s-57°43’35.71” 1342239739 OT1larmus1
194−671µm 18h13m39.50s-57°43’31.05” 1342192993 KPOTpvanderw1
NGC7469 11.65 1.32 0.01632 70.8 300 Sy1,SB [OI]63 23h03m15.47s+08°52’37.05” 1342187847 KPGTesturm1K
(IRAS23007+0836) [OI]145,[CII] 23h03m15.83s+08°52’28.52” 1342211171 KPGTesturm1K
194−671µm 23h03m15.87s+08°52’28.15” 1342199252 KPOTpvanderw1
NGC7552 11.11 3.64 0.00537 23.5 180 SB [OI]63 23h16m10.10s-42°34’53.89” 1342210400 KPGTesturm1K
(IRAS23134-4251) [OI]145,[CII] 23h16m10.59s-42°35’05.73” 1342210399 KPGTesturm1K
194−671µm 23h16m10.73s-42°35’06.02” 1342198428 KPOTpvanderw1
NGC7771 11.40 1.08 0.01427 61.2 250 SB [OI]63,[OI]145,[CII] 23h51m24.83s+20°06’42.33” 1342197839 KPOTpvanderw1
(IRAS23488+1949) 194−671µm 23h51m24.72s+20°06’42.11” 1342212317 KPOTpvanderw1
Mrk331 11.50 0.87 0.01790 79.3 215 SB [OI]63,[OI]145,[CII] 23h51m26.76s+20°35’09.83” 1342197840 KPOTpvanderw1
(IRAS23488+2018) 194−671µm 23h51m26.65s+20°35’10.42” 1342212316 KPOTpvanderw1
Note.—
Column1:Objectname.
Column2:log(LIR/L(cid:12))fromArmusetal.(2009).ObservationsusethecosmologicalparametersH0=70kms−1Mpc,Ωvaccum=0.72,andΩmatter=0.28.
Column3:Farinfraredflux(FIR)calculatedusingtheIRASdefinition(Helouetal.1985)in10−12Wm−2.
Column4:RedshiftzfromNED.
Column5:LuminositydistanceDLinMpcfromArmusetal.(2009).
Column6:CO1-0fullwidthtohalfpowerlinewidthinkms−1.
Column7:GalaxyclassificationfromNEDSB=Starburst,L=LINER,AGN=ActiveGalaxyNucleus,Sy1=Seyfert1,Sy2=Seyfert2,QSO=Quasi-StellarObject.
Column8:Linenames.
Column9:PointingCoordinates.
Column10:ObservationID(OBSID).
Column11:ProgramID.
aThetwoSPIREobservationsofIRASF05189–2524werecombinedusingHIPEaverage(avg)task.
8
3 for NGC 7552, Mrk 331, and IRAS F17207–0014,
respectively. It is important to note that the baseline
ripple seen in the SPIRE FTS spectra is due to both
the sinc profile of the strong CO transitions and the
noise. Sinceinthispaperweonlydiscusstheneutral
gas cooling, we do not present fluxes of [NII] (which
originatesinionizedgas)orthemolecularlinesother
than CO, which are irrelevant to the total neutral gas
cooling. A comprehensive set of fluxes will be pre-
sented in Van der Werf et al. (in prep). In addition,
theHerMESteamisplanningtopublishaformaldata
paperusingHIPEv12.0withadetailederroranalysis
inthenearfuture.
In the bottom row of the spectra in Figures 1, 2,
and 3, the PACS line profiles of the three sample
galaxies are presented (NGC 7552, Mrk 331, IRAS
F17207–0014).
9
==========ObjectCOJ4-3COJ5-4COJ6-5COJ7-6COJ8-7COJ9-8COJ10-9COJ11-10COJ12-11COJ13-12[CI][CI][OI][OI][CII]60937063145−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−17217217217217217217217217217217217215215215210Wm10Wm10Wm10Wm10Wm10Wm10Wm10Wm10Wm10Wm10Wm10Wm10Wm10Wm10WmaNGC34–1.662.232.542.692.832.432.421.981.520.751.250.67(0.82)0.07(0.07)0.71(0.72)+MCG12–02–001*3.073.743.312.692.362.001.381.69–1.181.052.591.60(1.60)0.10(0.11)2.08(2.06)aIC16234.255.403.673.412.652.291.780.310.861.912.403.830.87(1.29)0.08(0.08)2.26(2.27)NGC1068*25.2424.2724.2724.6325.3118.0016.5216.2714.248.3716.7434.945.70(4.88)0.27(0.27)3.09(2.96)NGC1365*41.7341.9236.7526.1524.0616.1710.198.484.651.7519.6231.841.37(1.40)0.11(0.12)4.33(4.29)NGC16142.613.563.213.433.422.522.381.290.980.851.102.672.24(2.29)0.19(0.19)2.46(2.36)IRASF05189–2524–0.740.960.871.300.821.541.201.101.010.250.610.10(0.15)0.01(0.01)0.17(0.15)NGC2146*17.0319.3920.6817.7714.7612.7710.827.422.525.635.6815.322.78(2.74)0.43(0.43)7.65(7.60)aNGC26231.922.182.552.843.343.063.102.891.912.220.862.440.40(0.71)0.08(0.08)0.60(0.61)NGC3256*17.6619.2222.7118.9319.6814.3011.829.254.804.547.8715.975.11(5.16)0.36(0.35)5.53(5.47)Arp299*11.269.8213.1312.5612.8115.2117.2715.4514.1617.672.7816.055.90(5.93)0.58(0.57)9.13(9.02)aESO320–G0304.394.565.174.543.694.073.972.482.151.191.723.420.77(2.87)0.06(0.06)1.63(1.66)bNGC44181.175.576.425.176.086.275.627.055.996.231.821.08-0.07(-0.13)–0.14(0.14)Mrk231–1.672.062.462.622.172.502.412.021.790.581.340.14(0.17)0.03(0.03)0.39(0.38)aIRAS13120–5453–5.125.086.706.555.275.114.053.072.332.355.391.09(1.57)0.08(0.10)1.33(1.34)bArp1933.203.023.583.413.142.592.371.991.000.901.353.701.21(2.23)0.12(0.13)1.52(1.54)NGC5135*3.533.773.973.042.491.951.501.031.020.423.366.181.18(1.14)0.09(0.09)1.60(1.54)aESO173-G015*12.1217.1419.1017.5216.8812.7511.8111.147.575.774.9014.481.48(1.73)0.22(0.21)2.53(2.51)aMrk273–1.892.552.822.962.683.342.301.581.910.511.760.39(0.69)0.07(0.07)0.74(0.73)bZw049.057–1.842.572.992.572.392.061.620.710.780.961.410.06(0.07)0.02(0.02)0.35(0.35)cArp2206.779.3512.0113.3914.5312.9910.2410.185.285.972.957.42-5.80(-5.97)-0.03(0.15)1.16(1.07)NGC62407.7810.8813.9016.6318.2916.8716.2214.0712.0810.522.049.546.25(5.99)0.50(0.46)3.74(3.57)aIRASF17207–0014–2.814.034.475.293.243.764.312.582.021.122.660.19(1.57)0.06(0.08)0.87(0.89)aIRASF18293–34135.887.197.556.244.343.462.811.540.981.324.257.432.56(4.95)0.23(0.24)4.82(4.89)IC46871.671.892.021.561.160.610.660.460.340.570.911.571.40(1.44)–2.69(2.68)NGC74693.244.574.233.743.102.611.911.591.271.192.144.631.72(1.77)0.16(0.15)2.04(2.02)NGC755212.3812.6212.9811.5510.736.864.254.261.921.485.4610.753.90(3.76)0.23(0.23)4.20(4.09)aNGC7771*4.494.834.593.492.262.170.991.590.150.855.867.290.60(0.95)–1.64(1.68)aMrk331*2.452.492.692.302.101.911.141.140.720.891.342.571.00(1.41)0.09(0.08)1.82(1.84) /Table2:abcdHerschelProfileshowsapartialabsorptionfeature.ProfileshowsinverseP-cygniprofile.Profileisinfullabsorption.Upperlimit.TheintegratedfluxesobservedwithSPIRE−−172inunitsof10Wm.Fluxerrorsare16%forallSPIREobservationsofgalaxiesthatarenotextended.Fortheextendedgalaxies(denotedwithanasteriskinthetable)Arp299,ESO+/Herschel173-G015,MCG12–02–001,Mrk331,NGC1068,NGC1365,NGC2146,NGC3256,NGC5135,andNGC7771,theerroris30%.ThelinesobservedwithPACSare[OI],63−−152[OI],and[CII]areinunitsof10Wm.ForthePACSobservations,thenumberinparenthesisisthefluxofthebestfitgaussianprofile.Thefluxescharacterizedbya’–’indicatethat145lineswerenotintheobservedspectralrange.Negativenumbersarelinesthatappearinabsorption(Arp220)orwithcomplexprofiles,suchasinverseP-cygniprofiles(NGC4418andZw049.057).
10