SDSS superclusters: morphology and galaxy content

0.88 MB·

by  M. Einasto

Astronomy&Astrophysicsmanuscriptno.AA23111 (cid:13)cESO2014
January15,2014
SDSS superclusters: morphology and galaxy content
M.Einasto1,H.Lietzen1,2,3,E.Tempel1,4,M.Gramann1,L.J.Liivamägi1,5,andJ.Einasto1,6,7
1 TartuObservatory,61602Tõravere,Estonia
2 InstitutodeAstrofísicadeCanarias,E-38200LaLaguna,Tenerife,Spain
3 UniversidaddeLaLaguna,Dept.Astrofísica,E-38206LaLaguna,Tenerife,Spain
4 NationalInstituteofChemicalPhysicsandBiophysics,Rävalapst10,Tallinn10143,Estonia
5 InstituteofPhysics,TartuUniversity,Tähe4,51010Tartu,Estonia
6 EstonianAcademyofSciences,EE-10130Tallinn,Estonia
4 7 ICRANet,PiazzadellaRepubblica10,65122Pescara,Italy
1
Received/Accepted
0
2
n ABSTRACT
a
J Context.Understandingtheformation,evolutionandpresent-daypropertiesofthecosmicwebandobjectsformingitisanimportant
taskincosmology.
4
Aims.We compare the galaxy populations in superclusters of different morphology in the nearby Universe (180 h−1Mpc ≤ d ≤
1
270h−1Mpc)toseewhethertheinnerstructureandoverallmorphologyofsuperclustersareimportantinshapinggalaxyproperties

insuperclusters.
]
O Methods.WefindsuperclustermorphologywithMinkowskifunctionalsandanalysetheprobabilitydensitydistributionsofcolours,
morphologicaltypes,stellarmasses,starformationrate(SFR)ofgalaxies,andthepeculiarvelocitiesofthemaingalaxiesingroups
C
insuperclustersoffilamentandspidertypes,andinthefield.WetestthestatisticalsignificanceoftheresultswiththeKStest.
. Results.Thefractionofred,early-type,lowSFRgalaxiesinfilament-typesuperclustersishigherthaninspider-typesuperclusters;in
h
low-densityglobalenvironmentstheirfractionislowerthaninsuperclusters.Inallenvironmentsthefractionofred,highstellarmass,
p
andlowSFRgalaxiesinrichgroupsishigherthaninpoorgroups.Insuperclustersofspidermorphologyred,highSFRgalaxieshave
-
o higherstellarmassesthaninfilament-typesuperclusters.Groupsofequalrichnesshostgalaxieswithlargerstellarmasses,alarger
r fraction of early-type and red galaxies, and ahigher fraction of low SFR galaxies, if they arelocated insuperclusters of filament
t morphology. The peculiar velocities of the main galaxies in groups from superclusters of filament morphology are higher than in
s
a thoseofspidermorphology.Groupswithhigherpeculiarvelocitiesoftheirmaingalaxiesinfilament-typesuperclustersarelocatedin
[ higherdensityenvironmentthanthosewithlowpeculiarvelocities.Therearesignificantdifferencesbetweengalaxypopulationsof
theindividualrichestsuperclusters.
1 Conclusions.Bothlocal(group)andglobal(supercluster)environmentsandevensuperclustermorphologyplayanimportantrolein
v theformationandevolutionofgalaxies.Differencesintheinnerstructureofsuperclustersoffilamentandspidermorphologyandthe
6 dynamicalstateofgalaxygroupsinthemmayleadtothedifferencesfoundinourstudy.
2
2 Keywords. Cosmology:Large-scalestructureoftheUniverse;galaxies:groups:general;Methods:statistical
3
.
1
01. Introduction richer,andtheycontainalargerfractionofred,non-starforming
4 galaxiesthanpoorsuperclusters(Einastoetal.2007a,b).
1ThelargescalestructureoftheUniverseisformedbyahierar-
:chy of galaxy systems from isolated galaxies to groups, clus- Early studies of galaxy environment showed that environ-
v
iters, and superclusters of galaxies. Galaxy superclusters, en- ments at the group and cluster scale affects the morphology
Xvironments for galaxies, and groups and clusters of galaxies, of galaxies, early-type, more luminous galaxies are located
rare the largest relatively isolated systems in the Universe are in higher density environments than late-type, fainter galax-
agalaxysuperclusters(deVaucouleurs1956;Jõeveeretal. 1978; ies(Einastoetal.1974;Dressler1980;Postman&Geller1984;
Einastoetal.1984,1994;Zuccaetal.1993).Tounderstandthe Einasto&Einasto1987;Hamilton1988;Einasto1991).Theen-
role of small-scale (group) and large-scale (supercluster) envi- vironmentaffectsthepropertiesofgalaxiesandgroupsofgalax-
ronments in galaxy formation and evolution, we need to study iesevenatlargerscales,upto10–15h−1Mpc(Einasto&Einasto
thepropertiesofsuperclustersandtheirgalaxyandgrouppopu- 1987; Moetal. 1992; Einastoetal. 2003a,b; Skibba 2009;
lationstogether. Tempeletal. 2011). In addition, groups of the same richness
Withthe adventofdeepsurveyscoveringlargeareasin the containalargerfractionofred,non-star-forminggalaxiesifthey
sky it became possible to determine the parameters of a large are located in rich superclusters compared to groups in poor
number of superclusters, and to study in detail the galaxy and superclusters or in low-density large-scale environments out-
group populations in them. These studies have revealed that side of superclusters (Einastoetal. 2008; Lietzenetal. 2012).
in richer superclusters groups and clusters of galaxies are also Luparelloetal. (2013) showed that the stellar population of
galaxiesingroupsinsuperstructuresissystematicallyolder,and
groups themselves are larger and have higher velocity disper-
Sendoffprintrequeststo:M.Einasto sionsthangroupswhichdonotbelongtosuperstructures.
Articlenumber,page1of14
A&Aproofs:manuscriptno.AA23111
Themorphologyofsuperclustershavebeenstudied,forex- We calculate the galaxy luminosity density field to recon-
ample,byCosta-Duarteetal.(2011)andEinastoetal.(2007c). struct the underlying luminosity distribution and to determine
Galaxysuperclustershavecomplexinnerstructuresthatcan be superclusters (extended systems of galaxies) in the luminosity
quantified with morphological descriptors as Minkowski func- densityfieldatsmoothinglength8h−1MpcusingB splineker-
3
tionals.Einastoetal.(2007c,2011a)foundinthewidemorpho- nel (see Einastoetal. 2007c, for comparison between B and
3
logicalvarietyofsuperclusterstwomaintypesofsuperclusters: Gaussiankernel).Wecreatedasetofdensitycontoursbychoos-
filaments and spiders. In filaments high-density core(s) of su- ingadensitythresholdsanddefinedconnectedvolumesabovea
perclusters are connected by a small number of galaxy chains certain density threshold as superclusters. In order to choose a
(filaments). In spiders there are many galaxy chains between proper density level to determine individual superclusters, we
high-densitycoresinsuperclusters.Poorspider-typesuperclus- analysed the properties of the density field superclusters at a
ters are similar to our Local supercluster with one rich cluster series of density levels. As a result we used the density level
andfilamentsofgalaxiesandpoorgroupsofgalaxiesaroundit D = 5.0(inunitsofmeandensity,ℓ = 1.65·10−2 1010h−2L⊙)
(Einastoetal.2007c). 8 mean (h−1Mpc)3
todetermineindividualsuperclusters(Liivamägietal.2012).At
Einastoetal. (2012a) analysed the structure of rich galaxy
this density level superclusters in the richest chains of super-
clusters in superclusters of different morphologiesand showed
clusters in the volume under study still form separate systems;
thatclusters in superclustersof spider morphologyhave higher
atlower densitylevelstheyjoin into hugepercolatingsystems.
probabilitiesofhavingsubstructureandtheirmaingalaxieshave
Athigherthresholddensitylevelssuperclustersaresmallerand
higher peculiar velocities than clusters in superclusters of fila-
theirnumberdecreases.
mentmorphology.
The morphologyof all superclustersused in this study was
Inthepresentstudywecontinueouranalysisofsuperclusters
determinedin Einastoetal. (2012a) applyingMinkowskifunc-
ofdifferentmorphology,studyingtheirgalaxyandgrouppopu-
tionals.Fora givensurfacethe fourMinkowskifunctionalsare
lations, to understand better how the large-scale (supercluster)
proportionalto the enclosed volume V, the area of the surface
environmentaffectsthepropertiesofgalaxiesandgroupsresid-
S,theintegratedmeancurvatureC,andtheintegratedGaussian
inginthem.Forcomparisonwealsoanalysegalaxycontentand
curvature χ (see Appendix B and Einastoetal. 2007c, 2011a,
grouppropertiesinlow-densityglobalenvironment(field).
fordetailsandreferences).Theoverallmorphologyof a super-
In Sect. 2 we describe the data about galaxies, groups, and
cluster is described by the shapefinders K (planarity) and K
1 2
superclustersusedinthispaper,inSect.3wecomparethegalaxy
(filamentarity),andtheirratio,K /K (theshapeparameter),cal-
1 2
contentandthepeculiarvelocitiesofthemaingalaxiesingroups
culated using the first three Minkowski functionals. The lower
insuperclustersofdifferenttype,andinthefield.Wediscussthe
thevalueoftheshapeparameter,themoreelongatedasuperclus-
resultsanddrawconclusionsinSect.4.
ter is. The maximumvalueof the fourthMinkowskifunctional
Weassumethestandardcosmologicalparameters:theHub-
V characterises the inner structure of the superclusters. The
ble parameter H = 100 h km s−1 Mpc−1, the matter den- 3
0 higherthevalueofV ,themorecomplicatedtheinnermorphol-
sity Ω = 0.27, and the dark energy density Ω = 0.73 3
m Λ ogyofasuperclusteris(Einastoetal.2007c,2011b).Superclus-
(Komatsuetal.2011).
terswereclassifiedasfilamentsandspidersonthebasisoftheir
morphologicalinformationandvisualappearance.Superclusters
showwidemorphologicalvarietyinwhichEinastoetal.(2011a)
2. Data
determined four main morphological types: spiders, multispi-
2.1.Galaxy,group,andsuperclusterdata ders,filaments,andmultibranchingfilaments.Spidersandmulti-
spidersaresystemsofoneorseveralhigh-densityclumpswitha
We use the MAIN sample of the 8th data release of the Sloan number of outgoing filaments connecting them. Filaments and
Digital Sky Survey (SDSS DR8) (Aiharaetal. 2011) with the multibranching filaments are superclusters with filament-like
apparentGalactic extinctioncorrectedr magnitudesr ≤ 17.77, mainbodiesthatconnectclustersinsuperclusters.Forsimplicity,
andtheredshifts0.009≤z≤0.200,intotal576493galaxies.We in thisstudywe classify superclustersas spidersandfilaments.
correctedtheredshiftsofgalaxiesforthemotionrelativetothe InAppendixBweshowanexamplesoffilamentandspider-type
CMBandcomputedthe co-movingdistances(Martínez&Saar superclusters.
2002)ofgalaxies. The description of the supercluster catalogues is given in
Galaxy groups were determined using the Friends-of- Liivamägietal. (2012), the details of supercluster morphology
Friends cluster analysis method introduced in cosmology by aregiveninEinastoetal.(2007c,2011a).
Zeldovichetal. (1982) and Huchra&Geller (1982). A galaxy Figure 1 presents the distribution of rich galaxy clusters
belongs to a group of galaxies if this galaxy has at least one in superclusters of filament and spider morphology,as well as
group member galaxy closer than a linking length. In a flux- from the field in cartesian coordinates x, y, and z defined as in
limitedsamplethedensityofgalaxiesslowlydecreaseswithdis- Parketal.(2007)andinLiivamägietal.(2012):
tance. To take this selection effect into account properly when
constructing a group catalogue from a flux-limited sample, we x=−dsinλ,
rescaledthelinkinglengthwithdistance,calibratingthescaling y=dcosλcosη,
relationbyobservedgroups(see Tagoetal.2008,2010,forde-
z=dcosλsinη,
tails).Asaresult,themaximumsizesintheskyprojectionand
thevelocitydispersionsofourgroupsaresimilaratalldistances. wheredisthefingerofgodcorrectedcomovingdistance,andλ
Ourinitialsampleischoseninthedistanceinterval120h−1Mpc andηaretheSDSSsurveycoordinates.
≤ d ≤340h−1Mpc(theredshiftrange0.04 < z < 0.09)where Up to distances of about 180 h−1Mpc the SDSS survey
the selection effects are the smallest (we discuss the selection crosses the void region between the Hercules supercluster and
effects in detail in Tagoetal. 2010; Einastoetal. 2012a). The the chain of rich superclusters farther away (the Bootes void,
details of data reduction and the description of the group cata- Kirshneretal. 1981). Two chains of galaxies, groups, and su-
loguecanbefoundinTempeletal.(2012). perclusters cross this void. At the distance interval of about
Articlenumber,page2of14
M.Einastoetal.:Sclgal

300
red,scl
2000
blue,scl
c/h)200 1500
p al
M g
_
y ( N1000
100
500
−300 −200 −100 0 100 200 300
0
x (Mpc/h)
150 200 250 300
D (Mpc/h)

100
10000 red,field
blue,field
h) 8000
c/
p 0
M
z ( _gal6000
N
4000
−100
2000
−300 −200 −100 0 100 200 300 0
x (Mpc/h) 150 200 250 300
Fig.1. Distributionofgalaxygroupswithatleastfourmembergalax- D (Mpc/h)
iesinsuperclustersin x,y,andzcoordinates.Redfilledcirclescorre-
Fig.2. Thedistributionofdistancesofredandbluegalaxies(redand
spondtogroupsinfilament-typesuperclusters.Blueemptycirclesde-
bluelines,respectively)insuperclusters(upper panel)andinthefield
note groups in spider-type superclusters. Grey crosses denote groups
(lowerpanel).
withatleast30membergalaxiesfromthefield.
culationsshowedthattheresultsforthenearanddistantsamples
180 h−1Mpc ≤ d ≤ 270 h−1Mpc the survey crosses a number
aresimilar,butthestatisticsofthenearsamplearenotveryreli-
of rich superclusters, including the Sloan Great Wall (detailed
able,thereforeinthepaperwepresentourresultsforthedistant
descriptionofthelarge-scaledistributionofsuperclusterscanbe
sampleonly.
foundin Einastoetal. 2011b,a). Atdistancesd > 270h−1Mpc
thereisanothervoidregion,andthefrequencyofsuperclusters
Table1.Numberofgalaxiesinfilamentandspider-typesuperclusters
inthisregionisverylow.ThisisalsoseeninFig.2whereweplot
andinfieldforflux-andvolume-limitedsamples.
thedistributionsofdistancestoredandbluegalaxiesdividedby
theircolourindexg−r=0.7(seeSect.2.2)insuperclustersand 120−180h−1Mpc 180−270h−1Mpc
inthefield.
Sample flux-lim vol-lim flux-lim vol-lim
We have different distance intervals with different large-
Filaments 517 500 8102 6664
scaledistributionsandrichnessofsystems.Fromtheseweanal-
Spiders 3497 3024 12030 9211
ysed data from two regions: a void region with poor systems,
Field 58712 50643 123230 93795
120 h−1Mpc ≤ d ≤ 180 h−1Mpc (near sample), and a super-
clusterregionwithrichsystemsofgalaxies180h−1Mpc≤ d ≤
270h−1Mpc(distantsample).Amongthe50superclustersstud-
ied, 35 are of spider morphology and 15 of filament morphol-
ogy. The supercluster data are given in Table A.1. We do not 2.2.Galaxyproperties
use data for very poor superclusters without any rich clusters
whosemorphologyisdifficulttodetermine(fordetailswerefer Inthepresentpaperweusetheg−rcoloursofgalaxiesandtheir
toEinastoetal.2012a). absolutemagnitudesinther-bandMr.Theabsolutemagnitudes
ofindividualgalaxiesarecomputedaccordingtotheformula
Our data are based on a flux-limited sample of galaxies in
which absolute magnitude limit increases with distance, intro- M =m −25−5log (d )−K, (1)
ducing selection effects: there are relatively more red galaxies r r 10 L
at great distances (this can also be seen in Fig. 2). In order to whered istheluminositydistanceinunitsofh−1MpcandK is
L
avoidthisselectioneffectweusedvolume-limitedsampleswith the k+e-correction. The k-corrections were calculated with the
M ≤ −18.5 in near samples, and M ≤ −19.5 in distant sam- KCORRECT(v4_2) algorithm (Blanton&Roweis 2007) and
r r
ples. The numbers of galaxies in near and distant samples of the evolution corrections have been calibrated according to
superclusters are given in Table 1. The number of galaxies in Blantonetal.(2003).Weuse M = 4.53(inr-filter).Allofour
⊙
filament-typesuperclustersfromnearsampleis small.Our cal- magnitudesandcolourscorrespondtotherest-frameatredshift
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A&Aproofs:manuscriptno.AA23111
z = 0. The value g−r = 0.7 is used to separate red and blue phology,and from the field. We show the distributionsof late-
galaxies,redgalaxieshavingg−r ≥0.7.Weusedthemorphol- typegalaxiesonly;thedistributionsofearly-typegalaxiesshow
ogyclassificationbyHuertas-Companyetal.(2011)whichgives similardifferencesbetweengalaxypopulations(p =1−p).The
e l
foreachgalaxyaprobabilityofbeingearlyandlatetype,p and valuesofquantilesofgalaxyparametersaregiveninTableC.1.
e
p, correspondingly.Approximately,we calla galaxylate type,
l
if pl >0.5,andearlytype,if pe >0.5. 4 F
To study the stellar masses logM and SFRs, we use 6 F S
s S Field
the MPA-JHU spectroscopic catalogue (Tremontietal. 2004; 5 Field 3
Brinchmannetal. 2004). In this catalogue the differentproper-
4
ties of galaxies are obtained by fitting SDSS photometry and d d 2
spectra with the stellar population synthesis models developed 3
byBruzual&Charlot(2003).Thestellarmassesofgalaxiesare 2
1
derived in the manner described by Kauffmannetal. (2003). 1
For the DR8 data the stellar masses are estimated from the
0 0
galaxy photometry (rather than the spectral indices Dn4000 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0
and Hδ used by Kauffmannetal. 2003). The SFRs are com- 1.5 g − r p _l
puted using the photometry and emission lines as described FS 0.75 FS
by Brinchmannetal. (2004) and Salimetal. (2007). For active 1.25 Field Field
galacticnucleiandgalaxieswithweakemissionlines,SFRsare 1.0
estimated from the photometry. For star-forming galaxies with 0.5
d0.75 d
strongemissionlines,theSFRsareestimatedbyfittingdifferent
emissionlinesinthegalaxyspectrum(Hα,Hβ,[Oiii]5007,[Nii] 0.50 0.25
6584,[Oii]3727,[Sii] 6716).Thestellar massesandSFRs are
0.25
takenfromtheSDSSCASdatabase.
0.0 0.0
Inthegroupcataloguethemaingalaxyofagroupisdefined
9.0 9.5 10.0 10.5 11.0 11.5 12.0 −2.0 −1.0 0.0 1.0
asthemostluminousgalaxyinther-band.Wealsousethisdef- M_star SFR
initioninthepresentpaper.Invirializedclustersgalaxiesfollow Fig.3. Probabilitydensitydistributionsofgalaxyg−rcolours(upper
theclusterpotentialwell,andsowewouldexpectthatthemain leftpanel),probabilitiesofbeinglatetype(p,upperrightpanel),stellar
l
galaxiesinclusterslieatthecentresofgroupsandhavelowpe- masses(logM inlog M ,lowerleftpanel),andstarformationsrates
s ⊙
culiarvelocities(Ostriker&Tremaine1975).Thereforethepe- (SFRs,inlog M /yr) forgalaxies inthesuperclusters of filament and
⊙
culiar velocity of the main galaxies in clusters is also an indi- spidermorphologyandinthefield.
cation of the dynamicalstate of the cluster (Cozioletal. 2009;
Einastoetal.2012b).Wecalculatethepeculiarvelocitiesofthe Thisfigureshows,firstofall,thatgalaxypopulationsinsu-
maingalaxies,|v |,andcomparethesevelocitiesforgroupsin perclusters and in the field are different, superclusters contain-
pec
superclustersofdifferentmorphology,andinthefield. ing a larger fraction of red, early-type, high stellar mass, and
low SFR galaxies than can be found in the field. These fig-
ures show that galaxy populations in superclusters of filament
3. Results and spider morphology are also different, superclusters of fil-
ament morphologycontain a larger fraction of red, early-type,
3.1.Superclustersofdifferentmorphology
low SFR galaxiesthan superclustersof spider morphology.All
We analyse galaxy populations in superclusters of different differences are statistically significant at very high confidence
morphology, and in the field using probability density distri- level(pKS <0.001).
butions which are calculated within the statistical package R The distribution of stellar masses of galaxies in filament
environment using the ’density’ command in the ’stats’ pack- andspider-typesuperclustersshowsthatinfilament-typesuper-
age (Ihaka&Gentleman 1996) 1. In Tables in Appendix C we clusters there is some deficit of low stellar mass galaxies with
presentthevaluesofquantilesoftheparametersanalysedinthe logMs < 10.25, and relatively more galaxies of higher stel-
paper. The distributionsof colours, probabilitiesof being early lar mass than in superclusters of spider morphology. In Fig. 4
orlatetype,stellarmasses,andSFRsarebimodalorasymmetri- we show the probabilitydensitydistributionsof colours,types,
cal;theuseoffulldistributionsintheanalysisandquantileval- and SFRs of high and low stellar mass galaxies in superclus-
uesinTablesisstraightforward.Tonottomaketablestooover- ters of filament and spider type. Table C.2 presents the values
crowdedwedonotincludeerrorstothetables;thestatisticalsig- ofquantilesoftheseparameters.Asexpected(see,forexample,
nificance of the differencesbetween differentgalaxyproperties Blanton&Moustakas 2009), among high stellar mass galaxies
have been found using the full data (the integral distributions) therearerelativelymorered,early-type,lowSFRgalaxiesthan
andtheKolmogorov-Smirnov(KS)test.Wegivethe p -values amonglowstellarmassgalaxies.Interestingly,thisfigureshows
KS
ofthetest,throughoutthepaper(fordetailsofthisapproachwe thatlowstellarmassgalaxiesinfilament-typesuperclustersare
refer to Einastoetal. 2008). We consider that the differences mainly blue, but in spider-type superclusters there is relatively
betweendistributionsarehighlysignificantifthe p value(the moreredgalaxiesamongthemincomparisonwithfilament-type
KS
estimated probability of rejecting the hypothesis that distribu- superclusters. These differences are statistically highly signifi-
tionsarestatisticallysimilar) p ≤0.05. cant, as also differences in galaxy types. Differences between
KS
Figure 3 present the distributions of galaxy g − r colours, SFRsofgalaxiesfromfilamentandspider-typesuperclustersdi-
probabilitiesofbeinglatetype(p),stellarmasses(logM ),and videdbystellarmassarelowandstatisticallyunsignificant,ac-
l s
SFRsforgalaxiesfromsuperclustersoffilamentandspidermor- cordingtotheKStest.
Next we divided galaxies by colours and SFRs as red, low
1 http://www.r-project.org SFRgalaxies(g−r ≥ 0.7,andlogSFR < −0.5,approximately
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M.Einastoetal.:Sclgal

F,h 5 F,h F,h
F,l F,l 1.5 F,l
5 S,h S,h S,h
S,l S,l S,l
1.0
d d d
2.5
2.5
0.5
0 0 0.0
0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 −2.0 −1.0 0.0 1.0
g − r p_l SFR
Fig.4. Probabilitydensitydistributionsofgalaxyg−rcolours(leftpanel),probabilitiesofbeinglatetype(p,middlepanel),andstarformations
l
rates(SFRs,inlog M /yr,rightpanel)forhigh(h,logM ≥ 10.25,solidlines)andlow(l,logM < 10.25,dashedlines)stellarmassgalaxiesin
⊙ s s
thesuperclustersoffilament(F,redlines)andspider(S,bluelines)morphology.

60% of all galaxies), blue, high SFR galaxies (g − r < 0.7, 0.008 0.020
F
and logSFR ≥ −0.5, 30% of all galaxies), and red, high SFR S
F
galaxies (g−r ≥ 0.7, and logSFR ≥ −0.5, 10% of all galax- 0.006 S 0.015
ies).Weplotthedistributionsoftheirstellarmassesandtypesin
d0.004 d0.010
Fig.5,andgivethevaluesofquantilesofthestellarmassesand
typesinTableC.3.Thisfigureshowsinterestingfeature:stellar
0.002 0.005
massesofred,lowSFRgalaxies,andblue,highSFRgalaxiesin
filament-typesuperclustersarehigherthaninspider-typesuper-
0.0 0.0
clusters, as were these masses in overall distributions (Fig. 3), 0 200 400 600 800 0 100 200 300
but stellar masses of red, high SFR galaxies have higher val- D1 D2
ues in spider-type superclusters. In filament-type superclusters 0.25
their stellar masses are close to the stellar masses of red, low 0.05 F
SFR galaxies, in spider-type superclusters their stellar masses 0.04 FS 0.20 S
areevenhigherthanthoseofred,lowSFRgalaxies.Thesegalax- 0.15
0.03
iesaremostlyoflatetype.Thusthisfigureshowsthathighmass d d
galaxiesare red, evenif they are of high SFR and of late type, 0.02 0.10
andthereisadifferenceintheirmassesindifferenttypesofsu- 0.01 0.05
perclusters. KS test shows that the differences between stellar
0.0 0.0
masses and types of high and low SFR galaxies from filament 0 25 50 75 100 0 5 10 15 20 25
and spider-type superclusters are statistically highly significant
D4 D8
forbothhighandlowSFRredgalaxies.
Fig.6. Distributionsofenvironmentaldensitiesatdifferentsmoothing
lengths(1,2,4,and8h−1Mpc)insuperclustersoffilament(redlines)
1.5
6 rbelude, ,l ohwig hS FSRF,R F andspider(bluelines)morphology.
red, high SFR
red, low SFR, S
1.0 4 brelude, ,h higighh S SFFRR
superclusters,theKStestshowsthatthedifferencesarestatisti-
d d
callysignificantatleast95%level.Ifdensitiesin filament-type
0.50 2 superclustersweresystematicallyhigherthaninspider-typesu-
perclusters then the differences between galaxy populations in
0.0 0 thesesuperclusterswererelatedtothedependenceofthegalaxy
9.5 10.0 10.5 11.0 11.5 0.0 0.2 0.4 0.6 0.8 1.0 morphologyontheenvironmentaldensity,butweseethatthisis
M_s p_l
notso.Innermorphologyofsuperclustersisimportant.
Fig. 5. Probability density distributions of stellar masses (logM, in
s We also calculated environmental densities around galax-
logM ),(leftpanel)andprobabilitiesofbeinglatetype(p,rightpanel),
⊙ l iesofdifferentcolourandSFRs.Figure7showsenvironmental
for red, low SFR galaxies (red lines), blue, high SFR galaxies (blue
lines),andforred,highSFRgalaxies(greylines)inthesuperclustersof densities at 8 h−1Mpc smoothing length around red, low SFR,
filament(solidlines)andspider(dashedlines)morphology.HighSFR blue,highSFR,andred,highSFRgalaxies,analysedabove.In
galaxieshavelogSFR ≥ −0.5,andlowSFRgalaxieshavelogSFR < this figure we see that blue, high SFR galaxies have somewhat
−0.5.Linesintheleftpaneldenotethesamepopulationsasintheright lower environmental densities around them than red, low SFR
panel. galaxiesin both type of superclusters. This is an evidence of a
large-scale morphology-density relation. Environmental densi-
Figure6showsthedistributionsofenvironmentaldensitiesat tiesaroundred,lowSFRgalaxiesinfilament-typesuperclusters
smoothinglengths1,2,4,and8h−1Mpcinfilamentandspider- have higher values than in spider-type superclusters. Environ-
type superclusters. At all smoothing lengths in these distribu- mentaldensitiesaroundred,highSFRgalaxiesinspider-typesu-
tionspoorgroupswithN ≤9dominateatlowdensities;higher perclustersareclosetothoseforbluegalaxies;infilament-type
gal
valuesofdensitiescorrespondtorichergroups.Figure6shows superclusters the densities around them have somewhat higher
a small deficit of intermediate-value densities in filament-type values.Infilament-typesuperclusterssomeofthesegalaxiesare
Articlenumber,page5of14
A&Aproofs:manuscriptno.AA23111

ters of spider morphology, SCL 019 and SCl 099. The super-
red, low SFR, F
.25 blue, high SFR clustersSCl027andSCl019aretherichestsystemsintheSloan
red, high SFR
GreatWall(Einastoetal.2011b).ThesuperclustersSCl099(the
red, low SFR, S
blue, high SFR Corona Borealis supercluster)and SCl 001 belong to the dom-
0.20 red, high SFR inant supercluster plane (Einastoetal. 1997, 2011a). Figure 8
shows galaxy populations in these superclusters, and Table 2
theresultsoftheKStest, wherewe comparegalaxycontentof
.15
filament-typesystemsandspider-typesystems.
d
Thegalaxypopulationsintheindividualrichestsystemsare
alldifferent.Comparisonofthegalaxypopulationsoftherichest
0.10
filament-typesuperclustersandspider-typesuperclustersshows
thatthedistributionsofalltheirgalaxypropertiesconsideredin
thispaperare differentatveryhighsignificancelevel,the frac-
.05
tionsof red, low SFR galaxiesin the richest filament-typesys-
tems are higher than those in the richest spider-type systems.
0.0 Fortherichestfilament-typesystemsTable2showsthatalltheir
5 10 15 20 25 galaxypropertiesexceptstellarmassesaredifferentatveryhigh
D8
significancelevel,thefractionofredgalaxiesintheSCl 001is
Fig. 7. Distributions of environmental density at smoothing length
higher than in SCl 027, and the fraction of galaxies with high
8 h−1Mpc around red, low SFR galaxies (red lines), blue, high SFR
SFR islower. Forthe richestspider-typesuperclustersonlythe
galaxies(bluelines),andred,highSFRgalaxies(greylines)insuper-
stellar masses of galaxies in them are different at statistically
clustersoffilament(solidlines)andspider(dashedlines)morphology.
highsignificancelevel,galaxiesinSCl099havinghigherstellar
massesthaninthoseSCl019.
locatedinaratherhigh-densityenvironment.Alldifferencesare

statisticallyhighlysignificant. 4
6 SCl027 SCl027
Our sample contain several very rich superclusters. We SCl001 SCl001
SCl019 SCl019
analyse their galaxy populations separately (Sect. 3.3). To see 5 SCl099 3 SCl099
whether our overallresults are affected by their dominancewe 4
repeatedallcalculationsexcludingtherichestsystemsfromthe d 3 d 2
sample.Allourresultsremainedthesame,thereforeneitherthe
2
superclustersfromtheSloanGreatWall,norotherveryrichsu- 1
perclustersdonotdominateinourresults. 1
0 0
0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0
3.2.Superclustersofdifferentshape g − r p_ l
SCl027 0.75 SCl027
Superclusterscan be divided into more and less elongatedsys- 1.2 SCl001 SCl001
SCl019 SCl019
temsaccordingtothevalueoftheirshapeparameterK /K .The 1.0 SCl099 SCl099
1 2
smaller the shape parameter,the moreelongateda supercluster 0.8 0.5
is.SuperclusterswithK /K <0.5(moreelongatedsystems)are d d
1 2 0.6
calledfilamenttype,andthosewithK /K ≥0.5belongtopan-
1 2 0.4 0.25
cake type being less elongated systems (Einastoetal. 2011a).
Costa-Duarteetal.(2013)analysedstellarpopulationsofgalax- 0.2
iesinsuperclustersofdifferentshape,usingshapeparameterto 0.0 0.0
characterisetheoverallmorphologyofsuperclusters.Similarly, 9.5 10.0 10.5 11.0 11.5 12.0 −2.0 −1.0 0.0 1.0
M_star SFR
we use the shape parameter to divide superclusters of filament
andspidertypesintosetsofmoreelongatedandlesselongated Fig. 8. The same as in Fig. 3 for the richest superclusters: filaments
SCl001andSCl027(reddashedandsolidlines),andspidersSCl019
systemsandcomparegalaxypopulationsinthem.Theresultsare
andSCl099(bluesolidanddashedlines).
presentedwiththeKStestinTable2.Forvolume-limitedsam-
plesgalaxypopulationsinmoreelongatedandlesselongatedsu-
perclustersof filament morphologyare statistically similar. KS
test shows that galaxy types and SFRs in more elongated and
3.4.Richandpoorgroupsinsuperclusters
less elongatedsuperclustersof spider type are differentat very
high significance level. Costa-Duarteetal. (2013) did not find
Mostgalaxiesare locatedingroupsofvariousrichness.There-
differences in galaxy populations in superclusters of different
fore, as a next step we compared the galaxy content of groups
shape,andwefoundthisforspider-typesystemsonly.Weanal-
of different richness in filament- and spider-type superclusters
ysed quite richsystems only,divingthem atfirst by theirinner
andinthe field.We dividedgroupsof galaxiesin superclusters
morphology.Thismayleadtothedifferencesinourresults.
andinthefieldaccordingtotheirrichnessasverypoorsystems
withN ≤3,poorgroupswiththenumberofmembergalaxies
gal
4 ≤ N ≤ 11,andrichgroupswithN ≥ 12.Thecomparison
3.3.Therichestsuperclusters gal gal
ofgalaxypropertiesinthreerichnessclassesaregiveninFig.9.
Next we comparedgalaxypopulationsin the richestindividual ForclaritywepresentinFig.9theresultsforgroupsfromsuper-
superclusters of both morphologicaltypes, the superclusters of clustersonly.TableC.4presentsthevaluesofquantilesofgalaxy
filamentmorphology,SCl 001and SCl 027,and the superclus- properties.
Articlenumber,page6of14
M.Einastoetal.:Sclgal
Table2.TheresultsoftheKStest(the p -values):comparisonofthe 4
KS > 11, F > 11, F
galaxypropertiesinfilament-andspider-typesuperclustersofdifferent 5 4 − 11 4 − 11
1 − 3 1 − 3
overallshapeandrichness. 4 >4 −11 1, 1S 3 >4 −11 1, 1S
1 − 3 1 − 3
(1) (2) (3) (4) (5) 3
d d 2
Moreelongatedandlesselongatedsuperclusters
2
Filaments Spiders
1
flux-lim vol-lim flux-lim vol-lim 1
p p p p
KS KS KS KS 0 0
g−r 0.515 0.735 0.331 0.107 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0
pl 0.099 0.535 0.003 0.011 1.4 g − r 1.0 p _l
logM <1e−5 0.153 0.524 0.350 > 11, F > 11, F
s 1.2 41 −− 131 41 −− 131
SFR 0.242 0.221 0.001 0.002
1.0 >41 −−11 13, 1S 0.75 >41 −−11 13, 1S
Therichestsuperclusters 0.8
d d0.5
Filaments Spiders 0.6
SCl001,SCl027 SCl019,SCl099
0.4
0.25
flux-lim vol-lim flux-lim vol-lim
0.2
p p p p
KS KS KS KS
0.0 0.0
g−r <1e−5 <1e−5 0.824 0.804
9.5 10.0 10.5 11.0 11.5 −2.0 −1.0 0.0 1.0
p <1e−5 <1e−5 0.001 0.127 M_star SFR
l
logMs <1e−5 0.063 0.012 <1e−5 Fig.9. ThesameasinFig.3forgroupsofdifferentrichnessinsuper-
SFR 0.001 0.003 0.003 0.079 clustersoffilamentandspidermorphology (redandbluelines).Solid
D <1e−5 <1e−5 <1e−5 <1e−5 lines show distributions for groups with at least 12 member galaxies.
8
Dashedlinescorrespondtodistributionsforgroupswith4≤N ≤11.
gal
DottedlinestosinglegalaxiesandgroupswithN ≤3.
gal
Notes.Columnsareasfollows:1:Galaxyproperties.g−r-colourin-
dex, pl-probabilityofbeingalatetype,logMs-logstellarmass,SFR Table3.TheresultsoftheKStest(the pKS-values):galaxyproperties
- log SFR, D8 - environmental density at 8 h−1Mpc scale smoothing in groups of different richness in superclusters of filament and spider
scale;2–5:thepKS-valueofthetest. morphology.
(1) (2) (3) (4)
Figure 9 shows that the richer the group, the larger is the Property N <4 4≤N ≤11 N ≥12
gal gal gal
fractionof red, early-type,low SFR, high stellar mass galaxies p p p
KS KS KS
init. We foundasimilartrendforgroupsinlow-densityglobal g−r 0.359 9e−05 0.122
environments. The KS test shows that differences between all p <1e−5 <1e−5 <1e−5
l
galaxyparametersfrompoorerandrichergroupsarestatistically logM 0.006 0.017 0.014
s
highlysignificant. SFR 3e-04 0.022 0.388
Figure 9 shows that colourdistributionsof galaxiesin very
poor groups with N ≤ 3 are very similar in superclusters of
gal
different type. The KS test shows that the differences are not Notes.Columnsareasfollows:1:Galaxypropertiesarethesameasin
statistically significant (Table 3). Galaxies in very poor groups Table2.2:thepKS-valuesofthetestforsinglegalaxiesandgroupswith
insuperclustersoffilament-typehavehigherstellarmassesthan 2-3membergalaxiesinsuperclustersoffilamentandspidermorphol-
ogy.3:thesameforgroupswith4-11member galaxies.4:thesame
galaxiesinsuperclustersofspider-type,andthefractionofhigh
forgroupswithatleast12membergalaxies.
SFR galaxies among them is smaller. For richer groups Fig. 9
showsthatgroupsofthesamerichnesshostgalaxieswithhigher
stellarmasses,andtheyhavealargerfractionofearly-typeand
phology.Theysuggestedthatrichgroupsinsuperclustersofspi-
redgalaxies,anda higherfractionof lowSFR galaxies,ifthey
der morphologymay be dynamicallyyoungerthan rich groups
arelocatedinsuperclustersoffilamentmorphology.Forcolours
in superclusters of filament morphology.Next we compare the
and SFRs the KS test says that the differences between groups
peculiarvelocitiesof the main galaxiesof groupsin superclus-
with less and more than 12 galaxiesare not statistically signif-
ters and in the field to obtain an estimate of the group’s dy-
icant. The stellar masses and types of galaxies are also signifi-
namicalstate, and to understandwhether the differencesin the
cantlydifferentinthecaseoftheserichnessclasses.Inthefield
dynamical state of groups may be related to the differences in
groups the fraction of red, low SFR galaxies is lower than in
theirgalaxycontent.Inthesecalculationswedidnotwanttouse
groupsof the same richnessin superclusters.Summarising,the
dataofallgroupssinceforverypoorgroupscalculationsofthe
galaxycontentofgroupsofthesamerichnessissomewhatdif-
peculiar velocities of their main galaxies are not reliable. Re-
ferentinsuperclustersoffilamentandspidermorphology.
centlyRibeiroetal.(2013)usedseveralmethodstoanalysethe
structureanddynamicalstateofgalaxygroupsandshowedthat
these methods give quite reliable results for groups with more
3.5.Thepeculiarvelocitiesofthemaingalaxiesofgroups
thantenmembergalaxies(Figure2andTable1in Ribeiroetal.
Einastoetal.(2012a)showedthatinsuperclustersofspidermor- 2013).We madecalculationswithseveralgrouprichnesslimits
phologyrichgroupswithN ≥50haveagreaterprobabilityof and foundthat the results are similar, but for richer groupsthe
gal
havingsubstructureandhigherpeculiarvelocities|v | of their sample size is smaller and this decreases the statistical signifi-
pec
maingalaxiesthanrichgroupsinsuperclustersoffilamentmor- canceoftheresults.ThereforeweusedgroupswithN ≥12in
gal
Articlenumber,page7of14
A&Aproofs:manuscriptno.AA23111
ouranalysis.We showthedistributionsofthevaluesofthepe- 4. Discussionandconclusions
culiarvelocitiesofthemaingalaxiesingroupsin superclusters
We showedthatthefractionof red,early-type,low SFRgalax-
andinthefieldinFig.10(leftpanel).
ies in superclusters of filament morphology is higher than in
Figure 10 shows that the distributions are clearly different. superclustersof spider morphology.In addition,the fractionof
The KS test says that the differences of the peculiar velocities thesegalaxiesinsuperclustersishigherthanamonggalaxiesin
ofthemaingalaxiesingroupswithatleast12membergalaxies low-densityglobalenvironments.Thereare relativelymorered
insuperclustersoffilamentandspidermorphology,andbetween galaxies among low stellar mass galaxies in spider-type super-
supercluster and field galaxygroupsare statistically significant clustersthaninfilament-typesuperclusters.
atveryhighlevels(p-valuep<0.05).Thereisadeficitofgroups In superclusters of filament morphology groups of equal
withsmallvaluesofthepeculiarvelocitiesoftheirmaingalax- richnesshostgalaxieswithhigherstellarmasses,andtheyhave
iesingroupsfromsuperclustersoffilamentmorphology,andan alargerfractionofearlytypeandredgalaxies,andahigherfrac-
excess in groupsfromsuperclustersof spider morphology,and tion of low SFR galaxiesin comparisonwith groupsin spider-
in the field. Einastoetal. (2012b) showed for very rich groups type superclusters. In agreement with Lietzenetal. (2012), we
with Ngal ≥ 50thatingroupswiththepeculiarvelocitiesofthe found that groups of equal richness have a larger fraction of
maingalaxies|vpec| < 250kms−1 maingalaxiesarelocatednear early-type and red galaxies, and a higher fraction of low SFR
the centre of the group. Higher peculiar velocities of the main galaxies,iftheyarelocatedinhigh-densitylarge-scaleenviron-
galaxiessuggestthatthemaingalaxyislocatedfarfromthecen- ments (superclusters) rather than in the field. In superclusters
tre,a signof adynamicallyyounggroup.Figure10showsthat theyalsohostgalaxieswithhigherstellarmassesthangroupsin
the peculiar velocities of the main galaxies in groupsin super- the field. Luparelloetal. (2013) also found that galaxy groups
clustersoffilamentmorphologyarehigherthanthoseingroups in superstructures (Luparelloetal. 2011) have higher stellar
from superclusters of spider morphology, suggesting that they masses, highervaluesofthe peculiarvelocities,andhaveolder
aredynamicallyyounger.Intherichestgroupsweseetheoppo- galaxypopulationsthangroupsoutsideofsuperstructures.
site: here the peculiarvelocitiesof the main galaxiesin groups About10%ofallgalaxiesinbothtypesofsuperclustersare
from spider-type superclusters are higher than those in groups red, high SFR galaxies. These galaxies are mostly late type,
of filament-type superclusters, as also shown in Einastoetal. their stellar masses are similar to stellar masses of red, low
(2012a).Interestingly,wefoundthatgroupsofthesamerichness SFRgalaxies,andhigherthanthoseofbluegalaxies.Inspider-
containalargerfractionofred,passivegalaxiesinsuperclusters typesuperclusterstheirstellarmasseshavehighervaluesthanin
offilamentmorphologythaninsuperclustersofspidermorphol- filament-typesuperclusters.Earlierstudieshaveshownthatmas-
ogy,andthistrendissimilarforgroupsofdifferentrichness,but sive galaxiesare red, independentof their morphologicaltypes
thevaluesofthepeculiarvelocitiesdependonrichness. (Bamfordetal.2009;Mastersetal.2010;Einastoetal.2011b).
We found that red, high SFR galaxies can usually be found at
We also studiedthe relationbetweenthepeculiarvelocities
lowandintermediatedensitiesinbothtypeofsuperclusters,but
ofgroupmaingalaxies,andenvironmentaldensityinsuperclus-
someofthemare also locatedatregionsof quitehighenviron-
tersaroundthem,forseveralsmoothinglengths.Sincetheresults
were similar, we present them for smoothinglength 8 h−1Mpc mental density. Red, high SFR galaxies typically lie at inter-
mediate densities in small groups in superclusters (Wolfetal.
only (Fig. 10, right panel). This figure shows a possible weak
2005; Einastoetal. 2008; Skibbaetal. 2009), but they can be
correlationbetweenthepeculiarvelocitiesofthemaingalaxies
alsofoundinrichclusters,andamongthemaingalaxiesofclus-
and environmental density for filament-type superclusters, but
ters (Einastoetal. 2011b), in agreement with our present find-
not for spider-type superclusters. This was confirmed by Pear-
ings.Thismeansthatprocesseswhichchangethecoloursoflate-
son’scorrelationtestwhichshowedforfilament-typesuperclus-
typegalaxiestoredwhilekeepingthehighSFRmustoccurboth
ters that the correlation coeficient r = 0.19 with p = 0.06.
inhigh-andintermediate-densityregions,andaremoreeffective
For spider-typesuperclustersthis test foundthat r = 0.01with
on high stellar mass galaxies. We plan to study their location
p=0.93.
ingroupsandclustersofindividualsuperclusterstounderstand
theirdistributionandpropertiesbetter.
Einastoetal. (2008, 2011b) determineda large variation in
0.003
F 1250 F the distributions of different galaxy populations in individual
S S
Field richsuperclusters.Wefoundinthepresentstudyalargediversity
1000
0.002 m/s) inthepropertiesofgalaxypopulationsoftherichestsuperclus-
d0.001 v_pec (k 570500 toefrsgainlaoxuyrpsoapmuplaleti.oEnxspinlaisnuipnegrclalurgsteervsariisaatiocnhainlletnhgeedfisotrrigbaultaioxny
formationmodels.
250
Costa-Duarteetal.(2013)showedthatthereisnodifference
0.0 0 betweenstellarpopulationsofgalaxiesinsuperclustersclassified
0 250 500 750 1000 1250 1500 5 10 15 20
by their overall shape as filaments and pancakes. In our study
v_pec (km/s) D8
we foundthat when we divided superclusters of different mor-
Fig. 10. Left panel: the peculiar velocities of the main galaxies in phologyby their shape parameterinto moreelongatedand less
groups with at least 12 member galaxies in superclusters of filament elongatedpopulationsthenthedifferencesingalaxypopulation
andspidermorphology(redandbluelines),andinthefield(greyline).
betweenthemaresmall.
Rightpanel:thepeculiarvelocitiesofthemaingalaxiesingroupswith
Superclusters obtained their morphology and group and
atleast12membergalaxiesinsuperclustersoffilamentandspidermor-
galaxy populations during the formation and evolution of the
phology(redandbluedots)vs.environmentaldensityinsuperclusters
atsmoothinglength8h−1Mpc. cosmic web.In the Λ Cold Dark Matter (ΛCDM) concordance
cosmologicalmodelthestructuresformingthecosmicwebgrow
by hierarchical clustering driven by gravity (see Loeb 2002,
Articlenumber,page8of14
M.Einastoetal.:Sclgal
2008, and referencestherein).The present-daydynamicalstate stripping of cold gas by the hot gas of the diffuse intra-cluster
of clusters of galaxies depends on their formation history. We or intra-group medium (Gunn&Gott 1972), and strangulation
analysedthedynamicalstateofgalaxygroupsusingthepeculiar orremovalofgalactichalogas(Larsonetal.1980).Thesepro-
velocityoftheirmaingalaxiesasanindicatorofthedynamical cesses are effective both in galaxy groups and during mergers
state,andfoundthatthevelocitiesinfilament-typesuperclusters of groups into clusters (pre- and post-processing of galaxies,
are higher than those in spider-type superclusters. In this anal- Berrieretal.2009;Vijayaraghavan&Ricker2013).
ysiswe usedgroupswith N ≥ 12.In contrast,forthe richest Cen (2011) used hydrodynamicalsimulations to show that
gal
clusters with N ≥ 50 Einastoetal. (2012a) found that these for galaxies at z = 0 star formation is efficient in low-density
gal
velocitiesarehigherinsuperclustersofspidermorphology. regions while it is substantially suppressed in cluster environ-
Krauseetal. (2013) recently analysed the distribution and ments.Duringhierarchicalstructureformation,gasisheatedin
dynamicalstateofgalaxygroupsintheUrsaMajorSupercluster high-densityregions(groups,clusters,andsuperclusters),andan
(in our catalogue SCl 211 of filament morphology) and found increasinglylargerfractionofthegashasenteredaphasewhich
that groups with Gaussian velocity distribution of their mem- istoohottofeedtheresidinggalaxies.Asaresult,thecoldgas
ber galaxies are located in the denser regions of the super- supplytogalaxiesintheseregionsissuppressed.Theneteffect
cluster. They suggested that relaxed galaxy groups in the su- isthatstar formationgraduallyshiftsfromthe largerhalosthat
percluster have formed and evolved earlier and faster around populateoverdenseregionstolowerdensityenvironments.Thus,
high-densitypeaks, while nonrelaxedsystems may be growing a lack of coldgas dueto gravitationalheatingin dense regions
moreslowlyontheperipheriesoflowerdensitypeaks.Interest- may provide a physical explanation of cosmic downsizing and
ingly, we foundin this study a weak correlationbetween envi- oneofitsmanifestationsisobservedasthecolour-densityrela-
ronmentaldensityandthepeculiarvelocitiesofthemaingalax- tion.
iesingroupsinfilament-typesuperclusters,sothatgroupswith Summarising,ourresultsareasfollows.
higher values of the peculiar velocities of their main galaxies
are located in higher density environments, this is opposite to 1) Thefractionofred,early-type,lowSFRgalaxiesishigherin
theKrauseetal.(2013)result.Theystudiedonerichsuperclus- superclustersoffilament-typethaninsuperclustersofspider-
ter. We showedthatthe propertiesof individualrich superclus- type, higher in superclusters than among galaxies in low-
ters vary strongly.This may be the reason for different results. density globalenvironment,and higher in all environments
Einastoetal. (2011b) found in the study of the richest super- inrichgroupsthaninpoorgroups.
clustersintheSloanGreatWall, SCl027andSCl019,thatthe 2) Groups of equal richness host galaxies with higher stellar
peculiarvelocitiesofthemaingalaxiesingroupsdependonthe masses,andtheyhavealargerfractionofearly-typeandred
morphology of the main galaxies, and on their location in the galaxies, and a higher fraction of low SFR galaxies if they
supercluster. arelocatedinsuperclustersoffilamentmorphology.
Einastoetal. (2012a) assumed that superclusters of spider 3) Inspider-typesuperclustersthered,highSFRgalaxieshave
morphologyhavericherinnerstructurethansuperclustersoffil- higherstellarmassesandlowervaluesofenvironmentalden-
ament morphology with a large number of filaments between sitiesaroundthemthaninfilament-typesuperclusters.
clustersinthemsomergersofclustersmayoccurmoreoftenin 4) Thepeculiarvelocitiesofthemaingalaxiesingroupsinsu-
thesesuperclusters.Thereforeclustersinspider-typesuperclus- perclustersoffilamentmorphologyarehigherthaningroups
terscouldbedynamicallyyounger.Thisagreeswiththeresults in superclusters of spider morphology.In filament-type su-
of their galaxy populations,spider-type superclusters hosting a perclusters groups with higher peculiar velocities of their
largerfractionofblue,starforminggalaxies,butcontradictsthe main galaxies are located in higher density environments
calculationsofthepeculiarvelocitiesoftheirmaingalaxies.This thanthosewithlowpeculiarvelocities.
is one of the open questions for future studies of superclusters 5) Therearesignificantdifferencesbetweengalaxypopulations
andgalaxyclustersinthem. oftheindividualrichestsuperclusters.
Einastoetal. (2005) showed by numerical simulations that
Theseresultssuggestthatbothlocal(group)andglobal(su-
inlow-densityglobalenvironmentonlypoorsystemsform,these
percluster) environments,and inner structure and detailed den-
systemsgrowveryslowly.Inhigh-densityglobalenvironments,
sity distribution in superclustersare importantfactors affecting
thedynamicalevolutionisrapidandstartsearlier,consistingofa
theevolutionofgalaxiesandgalaxygroupsinthem.Ourstudy
continuaoftransitionsofdarkmatterparticlestobuildingblocks
indicatedseveralopenquestionsthatneedfuturestudies.Itisnot
ofgalaxies,groups,andclusters.Darkmatterhalosinvoidsare
clearhowthe processesthatshapethe propertiesofgalaxiesin
foundtobelessmassive,lessluminous,andtheirgrowthofmass
differentenvironmentsarerelatedtothesuperclusterscaleden-
issuppressedandstopsatearlierepochsthaninhigh-densityre-
sityfield,andhowthesuperclustermorphologyisrelatedtothe
gions.DuringthestructureformationintheUniverse,halosizes
properties of galaxies and groups in them. We plan to develop
in the supercluster core regionsincrease, while in void regions
furtherthemethodstoquantifyinnerstructureofsuperclusters,
halosizesremainunchanged(Tempeletal.2009).Thus,during
inordertounderstandbettertheroleofsuperclusterenvironment
theevolutionofstructuretheoveralldensityinsuperclustersin-
intheformationandevolutionofgalaxiesandgalaxygroupsin
creases, whichenhancestheevolutionofthe small-scaleproto-
them.We alsoplantostudytheinnerstructureofsuperclusters
halos in them (Suhhonenkoetal. 2011). This may lead to the
differences in the properties of galaxy groups and galaxies in usinggalacticfilaments(Tempeletal.2013).
theminsuperclustersandinthefield.
A number of processes that transform galaxies in high-
Acknowledgments
density environments have been proposed, either observation-
ally or in simulations. These include galaxy-galaxy merg- We thank the referee for invaluablecommentsand suggestions
ers (Barnes&Hernquist 1992), galaxy harassment (Richstone which helped to improve the paper. We thank Enn Saar for
1976; Mooreetal. 1996), tidal stripping by the host group or very fruitful collaboration on studies of supercluster morphol-
cluster’s gravitational potential (Gnedin 2003), ram pressure ogy. We are pleased to thank the SDSS Team for the publicly
Articlenumber,page9of14
A&Aproofs:manuscriptno.AA23111
available data releases. Funding for the Sloan Digital Sky Sur- Einasto,M.,Tago,E.,Jaaniste,J.,Einasto,J.,&Andernach,H.1997,A&AS,
vey (SDSS) and SDSS-II has been provided by the Alfred P. 123,119
Sloan Foundation, the Participating Institutions, the National Einasto,M.,Vennik,J.,Nurmi,P.,etal.2012b,A&A,540,A123
Science Foundation, the U.S. Department of Energy, the Na- Gnedin,O.Y.2003,ApJ,582,141
tionalAeronauticsandSpaceAdministration,theJapaneseMon- Gunn,J.E.&Gott,III,J.R.1972,ApJ,176,1
bukagakusho,and the Max Planck Society,and the HigherEd- Hamilton,A.J.S.1988,ApJL,331,L59
ucation Funding Council for England. The SDSS Web site is Huchra,J.P.&Geller,M.J.1982,ApJ,257,423
http://www.sdss.org/.TheSDSSismanagedbytheAstro-
Huertas-Company, M., Aguerri, J. A. L., Bernardi, M., Mei, S., & Sánchez
physicalResearchConsortium(ARC)fortheParticipatingInsti- Almeida,J.2011,A&A,525,A157
tutions.TheParticipatingInstitutionsaretheAmericanMuseum Ihaka,R.&Gentleman,R.1996,JournalofComputationalandGraphicalStatis-
of NaturalHistory, AstrophysicalInstitute Potsdam, University tics,5,299
ofBasel,UniversityofCambridge,Case WesternReserveUni- Jõeveer,M.,Einasto,J.,&Tago,E.1978,MNRAS,185,357
versity,TheUniversityofChicago,DrexelUniversity,Fermilab, Kauffmann,G.,Heckman,T.M.,White,S.D.M.,etal.2003,MNRAS,341,33
theInstituteforAdvancedStudy,theJapanParticipationGroup, Kirshner,R.P.,Oemler,Jr.,A.,Schechter,P.L.,&Shectman,S.A.1981,ApJL,
The Johns Hopkins University, the Joint Institute for Nuclear 248,L57
Astrophysics, the Kavli Institute for Particle Astrophysics and Komatsu,E.,Smith,K.M.,Dunkley,J.,etal.2011,ApJS,192,18
Cosmology,the KoreanScientistGroup,the Chinese Academy Krause,M.O.,Ribeiro,A.L.B.,&Lopes,P.A.A.2013,A&A,551,A143
of Sciences (LAMOST), Los Alamos National Laboratory,the Larson,R.B.,Tinsley,B.M.,&Caldwell,C.N.1980,ApJ,237,692
Max-Planck-Institutefor Astronomy(MPIA), the Max-Planck-
Lietzen,H.,Tempel,E.,Heinämäki,P.,etal.2012,A&A,545,A104
InstituteforAstrophysics(MPA),NewMexicoStateUniversity,
Liivamägi,L.J.,Tempel,E.,&Saar,E.2012,A&A,539,A80
Ohio State University, University of Pittsburgh, University of
Loeb,A.2002,Phys.Rev.D,65,047301
Portsmouth, Princeton University, the United States Naval Ob-
Loeb,A.2008,ArXive-print:0804.2258
servatory,andtheUniversityofWashington.
Luparello,H.,Lares,M.,Lambas,D.G.,&Padilla,N.2011,MNRAS,415,964
The present study was supported by the Estonian Science
Luparello,H.E.,Lares,M.,Yaryura,C.Y.,etal.2013,MNRAS,432,1367
FoundationgrantNo.8005,grants9428,MJD272,PUT246,by
Martínez,V.J.&Saar,E.2002,StatisticsoftheGalaxyDistribution(Chapman
theEstonianMinistryforEducationandScienceresearchproject
&Hall/CRC,BocaRaton)
SF0060067s08,andbytheEuropeanStructuralFundsgrantfor
Masters,K.L.,Mosleh,M.,Romer,A.K.,etal.2010,MNRAS,405,783
theCentreofExcellence"DarkMatterin(Astro)particlePhysics
Mo,H.J.,Einasto,M.,Xia,X.Y.,&Deng,Z.G.1992,MNRAS,255,382
and Cosmology" TK120. This work has also been supported
Moore,B.,Katz,N.,Lake,G.,Dressler,A.,&Oemler,A.1996,Nature,379,
by ICRAnet through a professorshipfor Jaan Einasto. H. Liet-
613
zen acknowledgesfinancial support from the Spanish Ministry
Ostriker,J.P.&Tremaine,S.D.1975,ApJL,202,L113
of Economy and Competitiveness (MINECO) under the 2011
Park,C.,Choi,Y.,Vogeley,M.S.,Gott,III,J.R.,&Blanton,M.R.2007,ApJ,
SeveroOchoaProgramMINECOSEV-2011-0187.
658,898
Postman,M.&Geller,M.J.1984,ApJ,281,95
References Ribeiro,A.L.B.,deCarvalho,R.R.,Trevisan,M.,etal.2013,MNRAS,434,
784
Aihara,H.,AllendePrieto,C.,An,D.,etal.2011,ApJS,193,29 Richstone,D.O.1976,ApJ,204,642
Bamford,S.P.,Nichol,R.C.,Baldry,I.K.,etal.2009,MNRAS,393,1324
Saar,E.2009,inDataAnalysisinCosmology,ed.V.J.Martínez&E.Saar&
Barnes,J.E.&Hernquist,L.1992,ARA&A,30,705
E.Martínez-Gonzalez&M.-J.Pons-Bordería(Springer-Verlag,Berlin),523–
Berrier,J.C.,Stewart,K.R.,Bullock,J.S.,etal.2009,ApJ,690,1292
Blanton,M.R.,Hogg,D.W.,Bahcall,N.A.,etal.2003,ApJ,592,819 563
Blanton,M.R.&Moustakas,J.2009,ARA&A,47,159 Saar,E.,Martínez,V.J.,Starck,J.,&Donoho,D.L.2007,MNRAS,374,1030
Blanton,M.R.&Roweis,S.2007,AJ,133,734
Sahni,V.,Sathyaprakash,B.S.,&Shandarin,S.F.1998,ApJL,495,L5
Brinchmann,J.,Charlot,S.,White,S.D.M.,etal.2004,MNRAS,351,1151
Bruzual,G.&Charlot,S.2003,MNRAS,344,1000 Salim,S.,Rich,R.M.,Charlot,S.,etal.2007,ApJS,173,267
Cen,R.2011,ApJ,741,99 Shandarin,S.F.,Sheth,J.V.,&Sahni,V.2004,MNRAS,353,162
Costa-Duarte,M.V.,Sodré,L.,&Durret,F.2013,MNRAS,428,906
Skibba,R.A.2009,MNRAS,392,1467
Costa-Duarte,M.V.,Sodré,Jr.,L.,&Durret,F.2011,MNRAS,411,1716
Coziol,R.,Andernach,H.,Caretta,C.A.,Alamo-Martínez,K.A.,&Tago,E. Skibba,R.A.,Bamford,S.P.,Nichol,R.C.,etal.2009,MNRAS,399,966
2009,AJ,137,4795 Suhhonenko,I.,Einasto,J.,Liivamägi,L.J.,etal.2011,A&A,531,A149
deVaucouleurs,G.1956,VistasinAstronomy,2,1584
Tago,E.,Einasto,J.,Saar,E.,etal.2008,A&A,479,927
Dressler,A.1980,ApJ,236,351
Einasto,J.,Einasto,M.,Saar,E.,etal.2007a,A&A,462,397 Tago,E.,Saar,E.,Tempel,E.,etal.2010,A&A,514,A102
Einasto,J.,Klypin,A.A.,Saar,E.,&Shandarin,S.F.1984,MNRAS,206,529 Tempel,E.,Einasto,J.,Einasto,M.,Saar,E.,&Tago,E.2009,A&A,495,37
Einasto,J.,Saar,E.,Kaasik,A.,&Chernin,A.D.1974,Nature,252,111
Tempel,E.,Saar,E.,Liivamägi,L.J.,etal.2011,A&A,529,A53
Einasto,J.,Tago,E.,Einasto,M.,etal.2005,A&A,439,45
Einasto,M.1991,MNRAS,252,261 Tempel,E.,Stoica,R.S.,Saar,E.,etal.2013,ArXive-print:1308.2533
Einasto,M.&Einasto,J.1987,MNRAS,226,543 Tempel,E.,Tago,E.,&Liivamägi,L.J.2012,A&A,540,A106
Einasto,M.,Einasto,J.,Müller,V.,Heinämäki,P.,&Tucker,D.L.2003a,A&A, Tremonti,C.A.,Heckman,T.M.,Kauffmann,G.,etal.2004,ApJ,613,898
401,851
Einasto,M.,Einasto,J.,Tago,E.,Dalton,G.B.,&Andernach,H.1994,MN- Vijayaraghavan,R.&Ricker,P.M.2013,MNRAS,435,2713
RAS,269,301 Wolf,C.,Gray,M.E.,&Meisenheimer,K.2005,A&A,443,435
Einasto,M.,Einasto,J.,Tago,E.,Müller,V.,&Andernach,H.2001,AJ,122, Zeldovich,I.B.,Einasto,J.,&Shandarin,S.F.1982,Nature,300,407
2222
Zucca,E.,Zamorani,G.,Scaramella,R.,&Vettolani,G.1993,ApJ,407,470
Einasto,M.,Einasto,J.,Tago,E.,etal.2007b,A&A,464,815
Einasto,M.,Jaaniste,J.,Einasto,J.,etal.2003b,A&A,405,821
Einasto,M.,Liivamägi,L.J.,Tago,E.,etal.2011a,A&A,532,A5
Einasto,M.,Liivamägi,L.J.,Tempel,E.,etal.2011b,ApJ,736,51
AppendixA: Superclusterdata
Einasto,M.,Liivamägi,L.J.,Tempel,E.,etal.2012a,A&A,542,A36
Einasto,M.,Saar,E.,Liivamägi,L.J.,etal.2007c,A&A,476,697
Einasto,M.,Saar,E.,Martínez,V.J.,etal.2008,ApJ,685,83 InTableA.1wepresentdataonsuperclusters.
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