Multi-wavelength Analysis of theMerging Galaxy Cluster Abell 115

2019. 02. 20 - 22

Mincheol KimJames Myungkook Jee

Kyle Finner, Nathan Golovich, David M. Wittman, R. J. van Weeren, W. A. Dawson

The 8th Survey Science Grop Workshop

https://arxiv.org/abs/1812.08797

Globalwealth:3.2×10'(￦ (3.17×10'*$)

Merging�Galaxy�ClusterIntro

Collisionvelocity:~2000𝑘𝑚/𝑠Dissipatedenergyofmergershock:~3×1012 ergs(Sarazin 2002)=>~8×10*4 kWh

Unitprice(￦/kWh)

Total Price(￦) # oftheEarth

Householdelectricity 281 2.34×1052 7.31×1034

Industrial electricity 73 6.10×1051 1.91×1034

• DoubleX-raypeaks (Formanetal.1981)- eachshowingaram-pressurestrippedtail

• ExtendedRadioRelic (Govoni etal.2001)–evidencefortheenergeticcollision

• Postmergersystem

• SubaruV-and𝒊:- bandCFHT𝑔:- and𝑟:- bandChandraACIS-IVLA1.4GHzNEDdatabase,Keck/DEIMOS&MMT/Hectospec

Merging�Galaxy�Cluster�Abell 115Intro

X-ray�Analysis�on�Abell 115Intro

Forman, 2015(poster,15yearsofChandrameeting)

• TemperaturemaximumbetweenX-raypeaks→theclustersareinteracting.

• Bothclustershostcool cores– usuallyfoundinrelaxedclusters.

• The locationoftheX-rayshock(ℳ ∼ 1.4 − 2.0)is coincidentwiththe west

endoftheradiorelic (Botteon etal.2016)→ Evidenceof GlancingMerger

Okabeetal.2010 MassContours:Okabeetal.2010

• Thereseemtobeoffsetsbetweengalaxypeaksandweak-lensingmasspeaksineachcluster.

→Theoffsets,ifreal,haveimportantimplicationsfordarkmatter.

• SouthernICMwasram-pressurestrippedandtrailsthemasspeak.

• NorthernX-raypeak leadsthemasspeak.

• Okabeetal.(2010)havenotestimatedindividualhalomasses.

Offset�Between�Galaxy�and�MassIntro

Membershipdetermination:GaussianMixtureModeling

• Spectroscopicredshiftgalaxycatalog(Golovich etal.2015andRines etal.2018)

• Velocitydispersion:Bi-weightestimator(Beersetal.1990)

• Dynamicalmass:𝑀 − 𝜎B scalingrelation(Saro etal.2013)

• Dynamicalmassestimation𝑀CDEFG = 16.3IJ.KLJ.M×10'*𝑀⨀𝑀ODPFG = 20.4I2.2L2.(×10'*𝑀⨀𝑀QRDSTR = 37.3IK.JLK.(×10'*𝑀⨀

Multi-wavelength�Ⅰ:�SpectroscopyNED�database,�Keck/DEIMOS (4.9�ks) &�MMT/Hectospec

2.Temperatureto𝑀KUU𝑀KUU − 𝑇 scalingrelation(Mantz etal.2016)

1.TemperaturemeasurementMEKALplasmamodel(Kaastra &Mewe 1993;Liedahl etal.1995)

3.𝑀KUU to𝑀JUUNFWhalowithconcentrationrelationofDutton&Macciò(2014)

𝑀QRDSTR = 20.48IJ.('L2.*4×10'*𝑀⨀𝑀CDEFG = 9.00I'.*MLJ.U2×10'*𝑀⨀𝑀ODPFG = 8.52I'.2ML'.4U×10'*𝑀⨀

Multi-wavelength�Ⅱ:�X-rayChandra/ACIS-I�(360�ks)

X-raymassestimation

WLMassEstimation

𝑀CDEFG = 1.58IU.*4LU.K1×10'*𝑀⨀𝑀ODPFG = 3.15IU.('LU.(4×10'*𝑀⨀𝑀QRDSTR = 6.41I'.U*L'.UM×10'*𝑀⨀

Multi-wavelength�Ⅲ:�Optical�(Weak-Lensing)Subaru�/�SuprimeCam (1.53�ks)

WhiskersoverWLmass WLmassovercolorcomposite

WLmassovergalaxyluminosity WLmassoverX-rayluminosity

• Twomassclumpsareclearlydetectedatthe3.8𝝈 and3.6𝝈 levels.

• Massdistributionisconsistentwith BCGs andgalaxyluminositydistribution.

• NooffsetbetweenX-raypeaks andmasspeaks.

Mass�to�Light�Ratio

Girardietal.2002

𝑴⊙/𝑳𝑩⊙ Global North South

Weak-lensing 771I''KL'JU 293I4'L'U* 413I42L'U*

X-ray 2154IJMKL21( 1003I'1*LJJ1 1001I'K2LJ'U

Dynamical 3837IK22LKMK 1744IJ1(L2UU 2120I2*2L2M*

𝑴⊙/𝑳𝑩⊙ ofAbell 115

WLprovidesphysicallyreasonablemassestimation!!Kauffmannetal.1999

Bensonetal.2000

Merging�Scenario

Initialinput:z=0.1972𝑉 _O = 244 ± 144𝑘𝑚/𝑠M1=1.58IU.*4LU.K1×10'*𝑀⨀M2=3.15IU.('LU.(4×10'*𝑀⨀

• Timesincepericenter (TSP):~600𝑀𝑦𝑟

• Maximumcollisionvelocity:~2000𝑘𝑚/𝑠

• Thevelocitydirection:< 25°

• Separationvector:< 19°with68%ofanalogs

• Preferstheoutgoingphase

->ShortTSPandparallelrelativevectortothe

separationvector

However,thisseemstocontradictthevisualimpressiongivenbythecometarytailsinX-ray

emission!

Wittmanetal.2018

Summary

• Weperformedamulti-wavelength(optical,X-ray,and

spectroscopy)analysisonthemerginggalaxyclusterAbell 115.

• Thedarkmatterdistributionhastwoclearpeaksthatare

consistentwiththegalaxyluminositydistributionandBCGs.

• Theweak-lensingmassofeachsubcluster isobtainedandthe

massratiois~1:3.

• Wereconstructthemergerscenarioofthecluster.