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Key words. ISM: supernovaremnants— X-rays:individual:
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Astronomy&Astrophysicsmanuscriptno.astroph February5,2008
(DOI:willbeinsertedbyhandlater)
A Detailed Observation of a LMC Supernova Remnant DEM L241
⋆
with XMM-Newton
AyaBamba1,MasaruUeno2,HiroshiNakajima3,KojiMori4,andKatsujiKoyama3
1 RIKEN(TheInstituteofPhysicalandChemicalResearch)2-1,Hirosawa,Wako,Saitama351-0198,Japan
e-mail:[email protected]
2 Department of physics, Faculty of Science, Tokyo Institute of Technology 2-12-1, Oo-okayama, Meguro-ku, Tokyo 152-
8551,Japan
e-mail:[email protected]
3 DepartmentofPhysics,GraduateSchoolofScience,KyotoUniversity,Sakyo-ku,Kyoto606-8502,Japan
e-mail:[email protected],[email protected]
4 Department of Applied Physics, Faculty of Engineering University of Miyazaki, 1-1 Gakuen Kibana-dai Nishi Miyazaki,
889-2192,Japan
e-mail:[email protected]
Abstract. WereportonanXMM-Newtonobservationofthesupernovaremnant(SNR)DEML241intheLargeMagellanic
Cloud.Inthesoftbandimage,theemissionshowsanelongatedstructure,likeakillifish,withacentralcompactsource.The
compactsourceispoint-like,andnamedasXMMUJ053559.3−673509.Thesourcespectrumiswellreproducedwithapower-
lawmodelwithaphotonindexofΓ=1.57(1.51–1.62)andtheintrinsicluminosityis2.2×1035ergss−1inthe0.5–10.0keV
band,withtheassumeddistanceof50kpc.Thesourcehasneithersignificantcoherentpulsationsin2.0×10−3Hz–8.0Hz,nor
timevariabilities.Itsluminosityandspectrumsuggest thatthesourcemight beapulsar windnebula(PWN)inDEML241.
ThespectralfeatureclassifiesthissourceintoratherbrightandhardPWN,whichissimilartothoseinKes75andB0540−693.
Theelongateddiffusestructurecanbedividedintoa“Head”and“Tail”,andbothhavesoftandline-richspectra.Theirspectra
arewellreproducedbyaplane-parallelshockplasma(vpshock)modelwithatemperatureof0.3–0.4keVandover-abundance
inOandNeandarelativeunder-abundanceinFe.Suchanabundancepatternandthemorphologyimplythattheemissionis
fromtheejectaoftheSNR,andthattheprogenitorofDEML241isaverymassivestar,morethan20M⊙.Thisresultisalso
supportedbytheexistenceofthecentralpointsourceandanOBstarassociation,LH88.Thetotalthermalenergyandplasma
massare∼4×1050ergsand∼200M⊙,respectively.
1. Introduction (Williamsetal.,1999)andthenumbermaystillincrease(e.g.,
Chuetal., 2004). However, we have only few samples for
Supernovae(SNe)andsupernovaremnants(SNRs)shapeand
which type and age are known.The pulsars andtheir nebulae
enrich the chemical and dynamical structure of the interstel-
are a clear evidenceofcore-collapsedoriginandare goodin-
lar mediumandclouds. X-ray studiesgive us plentyof infor-
dicatorsoftheirage.Now,onlyfourLMCSNRsarereported
mation about hot plasma in SNRs with emission lines from
to have a pulsar and/orPWN; B0540−693(Manchesteretal.,
highly ionized ions. Moreover, SNRs are believed to be cos-
1993),N157B(Wangetal.,2001),B0532−710(Klingeretal.,
mic ray acceleratorsaroundtheirpulsar andpulsar windneb-
2002; Williamsetal., 2005), andB0453−685(Gaensleretal.,
ula(PWN),and/orshockfronts.TheMagellanicClouds(MCs)
2003). This is mainly because of a lack of spatial resolution
arethebestgalaxiesforthesystematicstudyofSNRs, thanks
in previousradio andX-ray observations.Thus,searchingfor
to the known distance (50 kpc; Feast, 1999) and the small
new SNR containing pulsars and PWNe in the LMC is criti-
absorption column. Another subject of interest is supernova
caltocarryingoutasystematicstudyofthecontributionsfrom
explosions in starburst galaxies. The SNe of massive stars
SNRstointerstellarmediumintheLMC.
scatter light elements into such galaxies, and make an abun-
dance pattern different from those in normal galaxies (e.g., DEM L241 (0536−67.6) was identified as an SNR by
Umedaetal., 2002). The Large Magellanic Cloud (LMC) is Mathewsonetal. (1985). They found that DEM L241 shows
the nearest starburst galaxy (Vallenarietal., 1996), and thus the typical looped filamentary structure of an SNR with a
we can examine the influence of discrete massive SNe on size of ∼ 2′ in the optical image. The [S] to Hα ra-
the galaxy. Now, more than 30 LMC SNRs are cataloged tio is 0.6 (Mathewsonetal., 1985), which is typical of that
for SNRs. Radio emission in 843 MHz was also reported by
Sendoffprintrequeststo:AyaBamba Mathewsonetal.(1985),whichshowsshell-likestructurewith
AyaBambaetal.:ADetailedObservationofaLMCSupernovaRemnantDEML241withXMM-Newton⋆⋆ 3
similar size to the optical shell. Einstein detected relatively 3. Results
bright X-rays (2.7× 1035 ergss−1 in the 0.15–4.5 keV band,
3.1.ImageAnalysis
Mathewsonetal., 1985). It appears to be a blow-out of the
denseHregion,N59B,aroundtheOBstarassociationLH88 Figure 1 shows the XMM-Newton MOS 1+2 images of
(Chu&Kennicutt, 1988). A study of the echelle spectrum by DEML241inthe(a)0.5–2.0keVand(b)2.0–9.0keVbands.
Chu (1997) showsa relativelysmallexpansionvelocityanda The correction of the exposure time was performed, whereas
large intrinsic velocity width, implying that the SNR may be thesubtractionofbackgroundphotonswasnotcarriedout.In
expandingwithinthestellar-windblowncavity,whichsuggests the soft band image, we can see a diffuse structure elongated
thattheprogenitorofDEML241islikelytobeamassivestar. fromsoutheastto northwestwith the size of ∼ 1.′5×3′ , cor-
Nishiuchi(2001)observedthisSNRwithASCA,andfoundthat respondingto22pc×44pcat50kpc.Theshapeislikeakilli-
the spectrum of the remnant requires not only thermal emis- fish,withadoublepeakedfeatureonits“Head”and“Tail”(see
sion but also a power-law componentwith Γ ∼ 1.6. This re- Figure1).Inadditiontothebodyofthefish,thereisacompact
sult indicates that DEM L241 has a pulsar and/or a PWN, or sourcelikean“eye”ofthefish.Ontheotherhand,onlytheeye
synchrotronX-rayemittingshellslikeSN1006(Koyamaetal., canbeseeninthehardbandimage.
1995; Bambaetal., 2003). However, the lack of spacial reso- We determined the position of the point-like source with
lutionofASCApreventedusfromconcludingtheoriginofthe the MOS 1+2 image, using the edetect command in SAS,
hardX-rayemission. to be (05h.35m.59s.93, -67d.35m.09s.72), then named the source
as XMMU J053559.3−673509. Although counterparts were
In this paper, we report the detailed X-ray analysis of
searched for with the SIMBAD data base, we found no can-
DEM L241 for the first time using XMM-Newton, with the
didateinanywavelength.Hereafter,werefertothissourceas
helpofASCAdata.§2summarizesthedetailsofXMM-Newton
Source 1. The radial profile of Source 1 was made with the
andASCAobservationsofDEML241.Theanalysisresultsare
2.0–9.0keVMOS1+2dataasshowninFigure2.Thesource
writtenin§3.§4isdevotedtothediscussionabouttheoriginof
is as compact as the PSF of XMM-Newton. The fitting of the
theremnant.WeassumethedistancetotheLMCtobe50kpc
profilewith a singleKingprofilemodelwasacceptedstatisti-
(Feast,1999)inthispaper.
callywithreducedχ2of18.0/17.Thebest-fitcoreradiusis3′.′1
(2′.′4–3′.′9)(hereafter,theparenthesesindicatesingleparameter
90% confidence regions), which is same as the PSF of MOS
CCDs. Therefore, we concluded that Source 1 is not signifi-
cantlyextended.Theupper-limitofthesourcesizeis1.0pc.
2. ObservationsandDataReduction Figure 3 shows the [S] gray scale image
(Mathewsonetal., 1985), overlaid on the MOS 1+2 0.5–
XMM-Newton (Jansenetal., 2001) EPIC cameras 9.0 keV contour map. The [S] emission, which traces the
(Stru¨deretal.,2001;Turneretal.,2001)observedDEML241 shock front, surrounds the Head region with two strong
on December 29 2004 (observation ID = 0205380101). The and weak rims on northeastern and southwestern sides. The
on-axispointspreadfunction(PSF)is5′′ forMOSCCDsand 843 MHz map by Mathewsonetal. (1985) basically agrees
6′′ forpn,infullwidthhalfmaximum.Themediumfilterwas withthe[S]map.ThenorthernpartoftheHeadisalsobright
used for all three EPIC cameras to block ultraviolet photons in the light of [O] (Mathewsonetal., 1985). There is no
(Stephanetal., 1996; Villaetal., 1998). In this observation, enhancement around the Tail region in both [S] and radio
both EPIC MOS and pn cameras were operated in the full maps,althoughthe field of viewof the[S] mapis toosmall
framemodeprovidinga time resolutionof2.6sand73.4ms, tocoverthewholeTailregion.
respectively. The data reductions and analysis were made
using Science Analysis System (SAS) software version6.1.0.
3.2.SpectralAnalysis
We filtered out background flares for rates in >10 keV band
more than 0.35 (1.0) counts s−1 for the MOS (pn) cameras, 3.2.1. Source1
resultingin45(43)ksofgoodtimeintervals.Inthefollowing
ThespectrumofSource1wasaccumulatedfroma15′′ radius
analysis, we use the grade pattern 0–12 events for MOS data
circlearoundthesourceforeachdetector.Thebackgroundan-
and0–4eventsforpndata,accordingtotheSASguide.
nularregionwasselectedwith20′′ innerradiusand30′′ outer
For the timing analysis, we used ASCA (Tanakaetal., radius.Figure4(a)showsthebackgroundsubtractedspectrum
1994) GIS (Gas Imaging Spectrometer, Ohashietal., 1996) of Source 1, which is very hard and has no line-like struc-
screened archive data of DEM L241, because GIS has better ture.Wefittedthespectraofthethreedetectorssimultaneously
time resolution than pn. The observation was carried out on with a power-law function plus absorptions.The galactic and
October 12–14 1999. Two GISs (GIS2 and GIS3) were op- LMC absorptions (N gal and N LMC, respectively) were cal-
H H
erated in the nominal pulse height mode. Only high bit data culated separately. We fixed N gal to be 5.56 × 1020 cm−2,
H
wasused,whichprovidesthebesttimeresolutionof62.5ms. which is estimated by Dickey&Lockman (1990), whereas
Thetotalexposuretimeis42ksforbothGISs.Toincreasethe N LMC was treated as a free parameter. Each absorption col-
H
statistics, the data of the two detectors, GIS2 and GIS3, were umn was subsequently calculated using the cross sections
combinedinthefollowingstudy. byMorrison&McCammon(1983) withthesolarabundances
4 AyaBambaetal.:ADetailedObservationofaLMCSupernovaRemnantDEML241withXMM-Newton⋆⋆
(Anders&Grevesse, 1989) for N gal, and the cross sections 3.3.TimingAnalysis
H
byBalucinska-Church&McCammon(1992)withtheaverage
Coherent pulsations were searched for in Source 1. We ex-
LMCabundances(0.3;Russell&Dopita,1992;Hughesetal.,
tractedphotonsfromthe2.0–8.0keVband(Source1isbright
1998)forN LMC.Thefittingwasacceptablewiththereduced
H inthisbandasseeninFigure4(a))andfroma15′′ radiuscir-
χ2 of365.1/376.Thebest-fitmodelandparametersareshown
clearoundSource1.Thecorrectionofthephotonarrivaltimes
inFig.4(a)andTable1.
wasdonetothoseatthebarycenter.AFastFourierTransform
(FFT)algorithmwasappliedtothepulsationsearch.We used
allthreeinstrumentsforthepulsationsearchfrom2×10−3Hz
3.2.2. Diffuseemission to0.19Hz,andonlythepnCCD,whichhasbettertimeresolu-
tionthantheMOSCCDs,forthe0.19–6.8Hzsearch.There-
sultingpowerdensityspectra(Figure5a,b)shownosignificant
ThediffuseemissioninDEML241showsanelongatedstruc-
peakfrom2×10−3 Hz to6.8Hz.Althoughwealso analyzed
ture with a “Head” and “Tail”. We divided the emission into
timingdataaccumulatedfroma5′′radiuscircleand/orphotons
theHeadandTailregionsasshowninFigure1(a).Thesource
in other wider andnarrowerbands, the resultsdid notchange
regionfor the spectralanalysis of the Head was made from a
significantly.
70′′ radiuscircleregionexcludinga30′′ radiuscirclearound
WealsoconductedthetiminganalysiswithASCAGISdata,
Source1.Ontheotherhand,theregionfortheTailwastaken
whichhasbettertimeresolutionthanMOSandpn.Thesource
as an elliptical shape with 50′′ × 90′′ radii. The background
photons were accumulated from a 3′ radius circle around
photonswere accumulatedfrom a source free regionnear the
Source 1, within the 2.0–8.0 keV band. After correcting the
SNR. These regionsare shown in Figure 1(a), with thick (for
photon arrival times to those at the barycenter, we applied a
thesources)andthin(forthebackground)lines.
FFT algorithm to search the coherent pulsation. No signifi-
cant pulsation was found up to 8.0 Hz again, as can be seen
Figure4(b)and(c)showthebackground-subtractedspectra
inFigure5(c).
oftheHeadandTailregions.Thespectraarebasicallysoftand
Figure 6 shows the light curve of Source 1 in the 2.0–
haveline-likestructure,implyingthatthereisatleastathermal
8.0keVband,whichisthecombinedresultofthethreeXMM-
emission component.The center energiesof these lines agree
Newtondetectors.WehavedonetheKolmogorov-Smirnovtest
with He-likeO, He-like Ne, andHe-likeMg. TheHeadspec-
forthislightcurveandfoundthatSource1 hasnosignificant
trum has an additional hard tail, which is probably contami-
time variabilityduringthe observationwith the probabilityof
nationfromthe brightSource1,sincethe fractionalencircled
constancyof0.72.
energywithin30′′ isonly∼90%.
We used the spectra of the three CCDs simultaneously 4. Discussion
and fitted them with a plane-parallel shock plasma (vpshock)
4.1.Theabsorption
model (Borkowskietal., 2001), packaged in xspec 11.3.1.,
with the galactic and LMC absorptions. The absorption cal- The best-fit N LMC in our analysis is almost consistent with
H
culationhasbeendoneinthesamewaytoSource1 case(see or slightly larger than the LMC absorption column estimated
§3.2.1). The abundances of the plasma were fixed to be 0.3 from the 21 cm line survey (8.4 × 1020 cm−2; Rohlfsetal.,
(Russell&Dopita, 1992; Hughesetal., 1998). For the spec- 1984),implyingthatthissourceisintheLMC.Thesmallex-
trum of the Head region, we added an additional power-law cessmightbeduetotheHexcessreportedintheHmapby
componentwhichrepresentscontaminationfromSource1.The Stavely-Smithetal. (1998). However, we can conclude noth-
valueofΓwasfixedtobe1.57,thebest-fitvalueforSource1 ing due to the lack of high sensitivity informationaroundthe
(Table 1). The fittings were rejected with the χ2/d.o.f. of SNR. More H observationswith better spatial resolution are
871.8/381(Head) and 607.1/300(Tail), with sinusoidalresid- requiredtodiscussthisissuequantitatively.
uals around O and Ne lines. Therefore, we allowed O, Ne,
and Fe abundances to vary freely following the previous re-
4.2.Source1
sult by Hughesetal. (1998). The fits were greatly improved,
and accepted statistically for both regions with reduced χ2 of ThecentralpositionofSource1,thehardspectrum,andpersis-
505.3/377(Head)and333.9/296(Tail).Thebest-fitmodelsand tentluminosityindicatethatSource1mightbeapulsarand/or
parameters are shown in Figure 4 (b) and (c), and Table 2, a PWN ofDEM L241.Thelack ofdetectionofcoherentpul-
respectively. We tried to but gave up being free the abun- sationisnotsurprising,sincetheperiodsofordinaryrotation-
danceofSi,becausethereisastrongbackgroundemissionline powered pulsars detected with X-rays are <≃0.1 sec. The hard
(Katayamaetal.,2004). spectrum also resembles the emission from background ac-
tive galactic nuclei (AGNs), although the source shows no
The flux of power-law component in the Head region is time variability. We estimate the probability of chance coin-
6.4±1.3%,which is consistentwith the expectedcontamina- cidence that there is a background AGN accidentally in the
tion of Source 1. Thus, we concluded that this hard excess is SNR region.With the logN—logS relationof AGNsderived
duetothecontaminationofSource1only,anddonotmention by Hasingeretal. (1998), we foundthatthe expectednumber
thiscomponenthereafter. ofAGNsisonly1.1×10−3inthe1.5′×3′region.Therefore,we
AyaBambaetal.:ADetailedObservationofaLMCSupernovaRemnantDEML241withXMM-Newton⋆⋆ 5
concludedthatSource1isanLMCmember.Thesimilarityof dant O relative to Ne might imply that the progenitor is very
theabsorptioncolumnforSource1tothatoftheHeadregion massive, >≃ 20M⊙ (Umedaetal., 2002). Umedaetal. (2002)
alsosupportthat.InthecasethatSource1isapulsarand/ora also insists that fast convective mixing in the progenitor star
PWN, this addsa new memberto the sample of LMCPWNe (Spruit, 1992) makes more Ne and less O. Therefore, we
(Gaensleretal.,2003).ThehardX-rayfluxdetectedbyASCA concluded that the progenitor of DEM L241 was very mas-
(Nishiuchi,2001)isconsistentwiththatofSource1.Thuswe sive star. This conclusion is also supported by the presence
consider that is not nonthermalemission from energeticelec- of the energetic pulsar candidate and the OB star associa-
tronsacceleratedontheshell,butthecentralpointsource.The tion, LH 88 (Chu&Kennicutt, 1988). The abundancepattern
distancefromSource1tothecenterofLH88isabout14′′,and of DEM L241 resembles in that of a starburst galaxy M82
thediaphragmdiameterofLH88is100′′ (Bicaetal.,1996), (Tsuruetal.,1997).ThisfactmightimplythatDEM241have
sotheprogenitormightbeamemberofthecluster. been producedin a period of starburstactivity of the OB star
TheintrinsicluminosityofSource1is2.2×1035 ergss−1 association. Umedaetal. (2000) and Nakamuraetal. (2001)
in the 0.5–10.0 keV band under the assumption that the have shown that a large Si/O ratio may be signature of ener-
distance to Source 1 is 50 kpc, and the photon index is geticSNexplosion(>≃ 1051 ergs).Thus,weneedtodetermine
1.57 (1.51–1.62). The luminosity and hardness ranges of Siabundancewithlowbackgroundobservations.
pulsars are wide, logL ∼ 31–36, Γ ∼ 0.6–2.0, respec-
x
tively (e.g., Gotthelf&Olbert, 2001; Gaensleretal., 2003).
Recently, “compact central sources” have been discovered
ThethermalemissionintheHeadregionhasacenter-filled
in several SNRs (Cas A, Chakrabartyetal. 2001; Vela Jr.,
morphologyevenconsideringthecontributionfromSource1.
Kargaltsevetal.2002;Kes79,Sewardetal.2003),whichhave
Note that the radius of the extent of the thermal emission is
rathersmallluminosities(logLx ∼32–34)andsoftspectra(Γ= ∼70′′ whilethatofSource1correspondstotheXMM-Newton
3–4).InthecasethatSource1isapulsaroracompactcentral PSF, ∼5′′. The structure, the radio shell (Mathewsonetal.,
source,Source1isoneofthebrightestsamples,andasbright 1985), and the large size of the SNR (see §3.1), classify
as the Crab pulsar (Pravdoetal., 1997). Such bright pulsars
the SNR as a mixed-morphology(MM) SNRs (Rho&Petre,
certainly havePWNe, which are about10 times brighterthan
1998).However,theover-abundantlightelementssuggestthat
thepulsarsthemselvesandalsohavehardspectra(logL =33–
x the emission is not from interstellar medium but ejecta as
37 and Γ =1.3–2.3; Gotthelf&Olbert, 2001). Thus, we con-
already mentioned, which is not common for ordinary MM
clude that the emission is from a PWN of DEM L241. Its
SNRs. Then, we concluded that this SNR is an ejecta dom-
photon index is rather small for ordinary PWNe. and sim-
inant SNR without X-ray emitting shells. The absence of a
ilar to those of the PWN in Kes 75 (Helfandetal., 2003)
limb-brightenedX-ray shell is expected, since this SNR is in
andB0540−693(Hirayamaetal.,2002).Helfandetal.(2003)
a hot and tenuous bubble (Chu, 1997) and it is hard to form
notesthatthesepulsarsystemschangetheirenergyintoX-ray
the strong shock. The elongated shape of the Tail region, to-
radiation very efficiently. Source 1 may be a new sample of getherwiththelackofenhancementof[S]andradiocontin-
suchenergeticPWNe.Source1ismoderatelybrightforPWNe,
uumemissionaroundTail,mightindicatethattheplasmawas
which mightimply that the system is middle-aged.Pulsars in
ejectedan-isotropicallyintoa low-densityregion.Itisnatural
suchPWNehaveperiodsoflessthanafewhundredmsecand
toconsiderthattheplasmaintheTailregionisablown-outon
luminositiesofabout10%oftheirnebulae.Thereforeitisnat- the basis of the [S] morphology.Chu (1997) suggested that
uralthatwecouldnotdetectthecoherentpulsationeveninthe
theSNR couldbeinteractingwith theinnerwallsofa bubble
casethatSource1hasapulsar.
to produce the SNR signature. In such a case, the interacting
InordertoconfirmtheoriginofSource1,itisessentialto region is heated and emits thermal X-rays, and the emission
resolve the pulsar spatially and to detect coherent pulsations. certainlytracestheshockregion,likethe[S]emission.Ifthe
Therefore,furtherobservationsareencouragedwithbettertime thermal emission is, on the other hand, center-filled, then we
andspatialresolution,andexcellentstatistics,intheX-rayand conclude that the thermal X-rays are not from the interacting
radiobands. regionbutfromtheejecta.
4.3.Diffuseemission
Inordertoestimatephysicalparametersoftheplasma,we
The temperature and abundance pattern of the hot plasma in assumedthattheplasmaintheHeadregionisdistributedina
the Head and Tail regions are roughly statistically the same spherewiththeradiusof70′′,excludingasphericalregionwith
as each other, (Table 2), implying that these plasmas have theradiusof30′′ aroundSource1(totalvolumeV =5.6×
Head
the same origin. The overabundant O and Ne relative to the 1059cm3),andthattheTailregionhasanellipsoiddistribution
average LMC indicate that the plasma emission is from the withtheradiiof50′′×50′′×90′′ (V = 4.0×1059 cm3),and
Tail
ejecta of the explosion, and that relative to Fe implies that calculatedthemeanelectrondensity(n ),theageoftheplasma
e
the progenitor of DEM L241 may be a core-collapsed SN (t ),thethermalenergy(E ≃3n VkT),andthetotalmassofthe
p e
(Tsujimotoetal., 1995). The Fe abundanceis slightlysmaller plasma(M =n m V,wherem istheprotonmass).Theresults
e p p
thantheavaragevalueintheLMC(0.22Hughesetal.,1998), are summarized in Table 3. The t indicates that the SNR is
p
it might be the local fluctuation of metal. The less abun- ratheraged,whichisconsistentwiththelargesizeoftheSNR.
6 AyaBambaetal.:ADetailedObservationofaLMCSupernovaRemnantDEML241withXMM-Newton⋆⋆
5. Summary Hirayama, M., Nagase, F., Endo, T., Kawai, N., & Itoh, M.
2002,MNRAS,333,603
We have conducted a detailed analysis of DEM L241 with
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XMM-Newton for the first time. A summary of our results is
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AyaBambaetal.:ADetailedObservationofaLMCSupernovaRemnantDEML241withXMM-Newton⋆⋆ 7
Williams,R.M.,Chu,Y.,Dickel,J.R.,Petre,R.,Smith,R.C., Table3.PhysicalparametersoftheplasmainHeadandTaila
&Tavarez,M.1999,ApJS,123,467
Table1.Best-fitparametersforSource1a Parameters Head Tail
n [cm−3].......... 0.28(0.26–0.29) 0.27(0.23–0.30)
e
t [106yrs]......... (>1.8) 1.1(>0.2)
p
Parameters E[1050ergs]b...... 2.9(2.2–3.7) 0.6(0.5–0.7)
Γ........................... 1.57(1.51–1.62) M[M⊙]........... 132(122–137) 89(76–99)
N LMC[1021cm−2]c.......... 3.3(2.7–4.0)
H
Flux[10−13ergscm−2s−1]c.... 6.4(6.0–6.8) a:Parenthesesindicatesingleparameter90%confidenceregions.
b:ThermalenergyEisestimatedtobe3n VkT.
e
a:Parenthesesindicatesingleparameter90%confidenceregions.
b:CalculatedusingthecrosssectionsbyMorrison&McCammon
(1983) with the average LMC abundances (Russell&Dopita,
1992).
c:In0.5–10.0keVband.
Table2.Best-fitparametersforthediffuseemissiona
Parameters Head Tail
vpshock
kT [keV]................ 0.39(0.38–0.40) 0.35(0.34–0.39)
e
n t [1012cm−3s].......... (>14.6) 9.0(>2.0)
e p
[O/H]b.................. 0.36(0.30–0.47) 0.47(0.36–0.64)
[Ne/H]b................. 0.82(0.74–0.96) 0.79(0.63–1.0)
[Fe/H]b ................. 0.09(0.07–0.11) 0.11(0.09–0.15)
E.M.[1058cm−3]c......... 4.4(3.8–4.8) 2.8(2.1–3.5)
N LMC[1021cm−2]d....... 5.6(4.7–6.4) 1.8(1.0–3.1)
H
Flux[10−13ergscm−2s−1]e. 3.2 3.6
Power-lawf
Flux[10−14ergscm−2s−1]e. 4.6(3.6–5.6) —
a:Parenthesesindicatesingleparameter90%confidenceregions.
b:Abundanceratiorelativetothesolarvalue(Anders&Grevesse,
1989).
c:E.M. = n 2V,wheren andV aretheelectrondensityandthe
e e
volume,respectively.
d:Calculatedusingthephotometricabsorptioncross-sectionsby
Balucinska-Church&McCammon (1992) with the LMC abun-
dances(Russell&Dopita,1992).
e:Inthe0.5–10.0keVband.
f:Γisfixedtothebest-fitvalueforSource1(1.57).
8 AyaBambaetal.:ADetailedObservationofaLMCSupernovaRemnantDEML241withXMM-Newton⋆⋆
Fig.2.MOS1+2radialprofileofSource1inthe2.0–9.0keV
band. The solid curve and crosses represent the best-fit King
profilemodelanddata,respectively.
-67o33’
-67o34’
-67o35’
-67o36’
05h36m10s 05h36m 05h35m50s
Fig.3. The [S] gray-scale map (Mathewsonetal., 1985),
overlaidontheMOS1+20.5–9.0keVcontourmapwithJ2000
coordinates.Thecontourisinthelogarithmicscale.
Fig.1. MOS 1+2 images in the (a) 0.5–2.0 keV and (b) 2.0–
9.0keVbands,withJ2000coordinates.Thescalesarelogarith-
mic,withunitsof×10−4 countss−1arcsec−2cm−2,asshownin
theleftbarforeachimage.Eachpictureisbinnedwith20pix-
els each and smoothed with 1′′ scale. The source and back-
groundregionsusedforthespectralanalysesareshownbythe
solidthickandthinlinesinthepanel(a).
AyaBambaetal.:ADetailedObservationofaLMCSupernovaRemnantDEML241withXMM-Newton⋆⋆ 9
(a) Newton all
(a)
(b) Newton pn
(b)
(c) ASCA GIS
(c)
Fig.4.SpectraofSource1(a),Head(b),andTail(c)regions. Fig.5. The power density spectra with the MOS1+2 and pn
Althoughwe fitted the spectra of MOS 1+2 and pn CCDs si- (a),pn(b),andASCAGIS2+3(c).Datapointsareplottedonly
multaneously,only the MOS 1 data and resultsare shown for whenwhosepowerislargerthan5.
brevity.Thebest-fitmodelsareshownwithsolid(vpshock)and
dotted(power-law)lines.Lowerpanelsinfiguresrepresentdata
residualsfromthebest-fitmodels.
10 AyaBambaetal.:ADetailedObservationofaLMCSupernovaRemnantDEML241withXMM-Newton⋆⋆
Fig.6. X-ray light curves of Source 1 with MOS1+2 and pn
CCDsinthe2.0–8.0keVband(bintime=1ks).
