Followthecosmicroarandchirp:Gravita5onalwave(GW)astrophysicsandSKA

SamayaNissankeRadboudUniversity,Nijmegen

Wasitaroarorchirp?

NewYorkTimes,Feb2016

Credit: LIGO Labs/Caltech

Today:firstGWdetec5ons

SeptembereventSNR∼23.7,>5.3σ

BoxingdayeventSNR∼13.0,>5.3σ

OctobercandidateSNR∼9.7,1.7σ

LIGOHanford LIGOLivingston

GW122615LVT151012GW150914

1

Credit: LIGO Labs/Caltech

NeutronStars(NS)

NSorBlackHole(BH)

Gravita5onalWave(GW)emission:1056ergs/s(finalorbits)10minspre-merger

~Solarluminosity×1023

~thevisibleUniverse’sgalac5cluminosity×50

Credit: NASA

2

Neutronstarbinarymergeristhenextdiscoveryandmustbedoneinreal-5me

EMemission??10spre-merger

10mspost-merger

NS

NSorBH

Credit: NASA

Electromagne5c(EM)radia5onprobesthemicrophysicsatplayinextremedynamical

space5mes

2

Recentchange:wenowhavethepoten5altodetectGWandEMradia5on

Gravita5onalradia5on EMradia5on

LIGO MeerKAT

LIGO MeerKATLearnaboutsources’dynamicandfundamentalproper5es

Learnaboutsources’environmentand

energe5cs

BlackGEMLSST BlackGEM

Meerkat3

SKAMeerKAT

EMcounterpartsofGWsources

Credit: NASA

SupermassiveBlackHoleBinaryMergers

withgas

AMCVn(mass-transferring

WhiteDwarfs)Credit: NASA

Credit: Bode, GIT

LowFrequencyGWs HighFrequencyGWs

Credit: CIT

NeutronStar(NS)BinaryMergers

Supernova

Credit: NASA

Credit: NASA

Pulsar

HeavyBINARYBLACKHOLES(BBH)??

4

1. Strongfieldgravityastrophysics Physicalprocessesinstronglycurvedspace-5mes

2. StellarEvolu5on Understandingthefateofcompactbinarystellar systems?

3. CosmicEnrichment Sitesofr-processnucleosynthesis

4. CosmologicalProbes MeasuringtheexpansionhistoryoftheUniverse

WhyshouldwecareaboutEMcounterparts?(somemo5va5on)

5

PlanofTalk

Part1:Introduc5ontoGWs

whatwelearnfromGWsalone?

Part2:Electromagne5c(EM)counterparts

whatwecanlearnfromGWsandEMtogether?

Part3:Howtodetectandiden5fytheradiocounterpartwithSKAI/II?

PartI:Introduc5onto

Gravita5onalWaves

Coherent,weaklyinterac5ng,bulkdynamicproper5esofmaierObservableGWstrainh(t)~1/distance

GWsareperturba5onsinthefabricofspace5meAccelera5ngquadrupolemaiersources

7

Credit: LIGO Labs/Caltech

Coherent,weak,bulkdynamicproper5esofmaier

GWsaretransverse5dalfields

8

LIGOLivingston

AdvancedkHzGWdetectorsprobestellar-massbinaryinspirals&/ormergers

h ⇠ �L

L⇠ 10�21

L=4km

fGW

⇠ 2forb

⇠ 1�

sGM

r3

12

advancedLIGO,Livingston

9

www.ligo.org

2015-16(O1)

2019(design)

Step-by-stepincreaseinsensi5vity(hencevolume)

2022(op5calsqueezing)

2010

10

GWdetectornetworkin2019

★★

LIGOL

LIGOH★

Virgo

11[seeroadmapinLSCandVirgocollabora5on--arXiv:1304.0670]

★

KAGRA(not@design)

z~1.4(BBH)~30BBHyr-1(mean)

z~0.1-0.2(NSbinaries)1-10NSNS/BHyr-1(mean)

SKAera:expandingtheGWdetectornetworkforEMfollowupin2022

★

KAGRA

★★

★

LIGOIndia

LIGOL

LIGOH★

Virgo

[seeroadmapinLSCandVirgocollabora5on—arXiv:1304.0670;Schutz2011,Nissankeetal.2013]

z~1.4(BBH)~30BBHyr-1(mean)

z~0.1-0.2(NSbinaries)1-10NSNS/BHyr-1(mean)

11

SKAera:GWdetectornetworkin2030(?)

★KAGRA

★★

★

LIGOIndia

LIGOL

LIGOH

★

Virgo

★EinsteinTelescope???

★

CosmicExplorer???

z~20(BBH)~1e5BBHyr-1(mean)z~2(NSNS/BH)>1e4NSNS/BHyr-1(mean)z~5(IMRI)0-10yr-1 11

[Scien5ficObjec5vesoftheEinsteinTelescope,arXiv:1206.0331]

Gravita5onalwavesopensanen5relynewwindowontotheUniverse

12[Mooreetal.,hip://rhcole.com/apps/GWploier/;]

[seeGemmaJanssen’sandVikramRavi’stalk]

Gravita5onalwavesopensanen5relynewwindowontotheUniverse

[Mooreetal.,hip://rhcole.com/apps/GWploier/;Jaffe,2004,arXiv:0409637]

[seeGemmaJanssen’sandVikramRavi’stalk]

AstrometrywithQSOsandSKA???

12

TheGWwaveformencapsulatesBinaryEvolu5on

[LVC,arXiv:1602.03837,PRL116,061102,2016] 135me(s)

0.30 0.40 0.450.35

[LVC,arXiv:1602.03837,PRL116,061102,2016]

5me(s)

Chirpmassdrivesinspiralwaveform

Inspiral∼Chirp

drivenbythechirpmass

Ringdown

…remnantmass&spin

chirpmass: 0.30 0.40 0.45

13

TheGWwaveformencodessourceparameters

Zoomin

5me(s)

spinmodula5on

h +(t)

[courtesyofPatriciaSchmidt]

�GW(t) ⇒chirpmass,reducedmass(1PN),spin-orbit(1.5PN),…

14

h(t):9-16dimensions+ Masses

+ Spins

+ NSequa5onofstate

+ Geometricproper5es:-Inclina5onangle-SourcePosi5on-Luminositydistance

[seee.g.CutlerandFlanagan1994,PoissonandWill1996…]

Extractsourceinforma5onfromGWs

15

[seee.g.Veitchetal.2015;LVC,arXiv:1602.03840,PRL116,241102,2016]

Likelihood

parameter2

Modelh(t)

Detectoroutput

Explicitlymapout:

Extractsourceinforma5onfromGWs

usingBayesianMarkovChainMonteCarloandNestedSamplingTechniques

h(t):9-16dimensions

15

parameter1

+ Masses

+ Spins

+ NSequa5onofstate

+ Geometricproper5es:-Inclina5onangle-SourcePosi5on-Luminositydistance

RetrievalofBHparametersm1∼36.2+5.2-3.8M⊙

m2∼29.1+3.7-4.4M⊙

m1∼14.2+8.3-3.7M⊙

m2∼7.5+2.3-2.3M⊙

[LVC,arXiv:1606.04856,PRX6,041015,2016]

[seeFransPretorius,AlviseRaccanelli,JoeSilk,LinjingShao’stalks]

16

…lengthofthechirp/roarsignal

longestinspiral

17[LVC,arXiv:1606.04856,PRX6,041015,2016]

Howwellcanwelocalisethesourceonthesky?

18[LVC,arXiv:1606.04856,PRX6,041015,2016]

[Imagecredit:LIGO/L.Singer/A.Messinger]

590[230]sq.deg.(90%c.r.)

1000[850]sq.deg.(90%c.r.)

1600sq.deg.(90%c.r.)

Howwellcanwelocalisethesourceonthesky?

[LVC,arXiv:1606.04856,PRX6,041015,2016]

[Imagecredit:LIGO/L.Singer/A.Messinger]

590[230]sq.deg.(90%c.r.)

1000[850]sq.deg.(90%c.r.)

1600sq.deg.(90%c.r.)

105-107galaxiesinthesevolumes 18

ExpandingtheGWnetwork

[LVC,arXiv:1606.09619,2016]

[Imagecredit:LIGO/L.Singer/A.Messinger]600->10-20sq.deg.(90%c.r.)

19

2015-2016 2019

[LVC,arXiv:1606.04856,PRX6,041015,2016]

SKAera:GWerrorsshrinkin2020s

[KasliwalandNissanke2014,ApJLei]

Twodetectors@designsensi5vity

Fivedetectors

GW150914:25EMfacili5espar5cipatedinfollow-up

19ordersofmagnitudeinfrequencyspace

21[LVC,APJL,826,1,L13,2016]

PartII:EMcounterparts

EMfromTwoTypesofMaierOu{lows

Credit: NASA

1.TidalTails+DiskWindsMej≈10-4-0.01M☉E≈1049-1050ergsv≈0.1-0.3c

(cf.Supernova:1051ergs)

[seee.g.,Rezollaetal.2010,2014,Stephensetal,2011,Eastetal.2011,Hotokezakaetal.,2012,2014,Rosswogetal.2012,Piranetal.2013,Bausweinetal.2013,Foucartetal.2014,Nagakuraetal.,2014,Kyutokuetal.2014,Fernandezetal.2014,Kiuchietal.2015,Lovelaceetal.inprep…]

2.Ultra-rela5vis5cJetMej≈10-6M☉E≈1049-1051ergsΓ≈100

[Fernandez & Metzger 2013]

22

[Foucart et el. 2014]

[Paschalidisetal.2015][Paschalidisetal.2016]

Sample BH/NS merger 2

rest mass density r

Newtonian e~1, rp = 7.0 M MNS0=1.35 M๏ (R=15.2km,M/R=0.13); MBH0=5.40 M๏disk mass ~ 0.41 M๏unbound material ~ 0.20 M๏~ 0.0043M energy emitted in GW’s

initially non-spinning BH, final BH spin a~0.33

2H EOS (Mmax=2.83 M๏)

(geometric time units, again duration~ 20 ms)

(slidecourtesyofFransPretorius)

[Stephensetal.2011,Eastetal.2011]

TwoTypesofMaierOu{lows

Credit: NASA

1.TidalTails+DiskWindsMej≈10-4-0.01M☉E≈1049-1050ergsv≈0.1-0.3c

2.Ultra-rela5vis5cJetMej≈10-6M☉E≈1049-1051ergsΓ≈100

[Fernandez & Metzger 2013]

[Rosswog 2012, 2013, 2015]

Ou{lows’kine5cenergyisconvertedintointernalenergy.Expands,coolsandheatedbyshocksorradioac5vity.

[Rezzolla et al. 2011]

24

1.PromptRadioEmission 2.ShortGammaRayBurst(SGRB)

3.Op5cal-nearIRkilo/macronova

4.SlowRadioRemnant

NS

BH

TwoTypesofOu{lows⇒FourEMcounterparts

[e.g., prompt radio emission: Hansen & Lyu5kov(2001),MoortgatandKuipjers (2002,5,6),Postnovand Pshirkov (2010), Lai (2012); kilonova: Li andPaczynski1998,Kulkarni2005,Metzgeretal.2010,Metzger & Berger 2012,…Barnes et al. 2013,Grossmanetal.2013,Tanakaetal.2013,Tanviretal.2013,Bergeretal.2013,… ;slowradio:NakarandPiran2011,Hotokezakaetal.,2015] 25

1.PromptRadioEmission 2.SGRB

3.OIRkilo/macronova4.SlowRadioRemnant

NS

BH

1/3:DifferentEMobservable5mescales

tmerger+secs tmerger+2s

tmerger+hours/daystmerger+month/yrs

25

1.PromptRadioEmission 2.SGRB

4.SlowRadioRemnant

NS

BH

2/3:EMemissiongeometry

semi-isotropic? beamed

semi-isotropic?isotropic?

3.OIRkilo/macronova

25

1.PromptRadioEmission 2.SGRB

4.SlowRadioRemnant

NS

BH

3/3:EMcounterpartsalreadyobserved?

maybe?observedbutaretheyNSmergers?

twocandidatesnotyetobserved[e.g., fast radio bursts: Thornton et al. (2013),Spitler et al. (2013); kilonova: Tanvir et al. 2013,Bergeretal.2013]

3.OIRkilo/macronova

25

+ Masses(severaltotens%)

+ Spins(tensof%)

+ NSradii

+ Geometricproper5es:(tensof%)-Inclina5onangle-SourcePosi5on-Luminositydistance

Fƛ(t):5-10dimensions

Nextstep:combine&interpretGW+EM

+ Energe5csandbeaming+ R-processnucleosynthesis+ Massejectaandvelocity+ Environment+ Redshi~,AccuratePosi5on(1”)+ Stellarpopula5ons+ Magne5cfieldstrength+ Previousbinaryevolu5on&massloss

(tensof%)

h(t):9-16dimensions

26

+ Masses(1%toseveral%)

+ Spins(severaltotensof%)

+ NSradii

+ Geometricproper5es:(tensof%)-Inclina5onangle-SourcePosi5on-Luminositydistance

fromEMsignature

Nextstep:combineandinterpretGW+EM

Popula5on:Demographics,ecologyandcensus

Strongsignalbinary:Characteriza5on

(tensof%)

fromtheGWchirp

26

+ Massejectaandvelocity+ Magne5cfieldstrength+ Energe5csandBeaming+ Redshi~,AccuratePosi5on

+ NuclearPhysics->Opaci5es

+ Stellarpopula5ons+ Previousbinaryevolu5on&massloss

JointGW+EMimprovescharacteriza5on

Nissankeetal.(2010)

27

Similarreasoningappliesdetec5ngBHmemory,tes5ngGRandneutronstarequa5onofstates…

H0error:3.4%

H0(km/s/Mpc)

Normalised

pdf 30binaries

GWenableafew%errorinHubbleconstant…importanceofpopula5ons!!!

[delPozzo,2012]

[Nissankeetal.,2010,13]

28[e.g.,Laskyetal.2016,Yunesetal.2013,Meidametal.2014,Lackay&Wade2014,Agathosetal.2014,15]

[seealsoSchutz1986,Dalaletal.2006,Sathyaprakash et al. 2010,

Messengeretal.2012,Tayloretal.2012,…]

NoEMcounterpart

PartIII:Howtofindandiden5fy

radiocounterpartswithSKA?

[withKentaHotokezaka(CCA->Princeton),GreggHallinan(CIT),JoeLazio(JPL),UdiNakar(TelAviv),TsviPiran(HU),arXiv1605.09395,ApJ]

PartIII:Howtofindandiden5fy

radiocounterpartswithSKA?

- unknown5meofemissionrela5vetothemerger- impossibleto5letheskywithsmallFoV- circumburstdensi5esmaybetoolow- toomanybubblingAGNfalseposi5ves MetzgerandBerger(2012)

BasicsofRadioA~erglowandRemnant

1.Kine5cEnergyisdissipatedattheShock

29

-Ejectacollideswiththeinterstellarmediumanddecelerates

-ShockamplifiesBandacceleratese-s

-Synchrotronradia5on

2.Brightness:energe5csoftheejecta

-Fastultra-rela5vis5cradioa~erglowSGRBs-Slowradioremnant

[NakarandPiran2011,Hotozekaka&Piran2015,Hotokezaka,Nissankeetal.2016]

Predictedradioremnantlightcurves

Credit: NASA

29

Highenergyejecta(1051erg,0.3c)

Lowenergy(1050erg,0.2c)

Medium

Highenergyjet20o,1049erg

Canonical20o,1048erg

[Hotokezaka,Nissankeetal,2016,arXiv1605.09395,ApJ]

Predictedradioremnantlightcurves

Credit: NASA

Highenergyejecta(1051erg,0.3c)

Lowenergy(1050erg,0.2c)

Medium

Highenergyjet20o,1049erg

Canonical20o,1048erg

[Hotokezaka,Nissankeetal,2016,arXiv1605.09395,ApJ] 29

5me(days)

Cri5caldependenceoncircumburstdensi5es

n=1/cm3

n=0.1/cm3

n=0.01/cm3

[Hotokezaka,Nissankeetal,2016,arXiv1605.09395,ApJ] 30

NSmergersdetectablewithSKA-1andSKA-2

31[Hotokezaka,Nissankeetal,2016,arXiv1605.09395,ApJ]

NSmergersdetectablewithSKA-1andSKA-2

[Hotokezaka,Nissankeetal,2016,arXiv1605.09395,ApJ] 31

1000AGN&starforminggalaxies

fewdozensofSNe(0.3-10years)

fewLGRBs(fewyears)

fewTDEs(fewyears)

unknowns

SingleSnapshotin100sq.deg@0.1mJylevel:

op5calcounterpart,>1Gpc

e.g.,ASKAP@3mJy,50deg2,1750sources

Howtopulltheneedlefromthehaystackintheradio?

32

[seeVikramRavi’stalk]

1000AGN&starforminggalaxies

fewdozensofSNe(0.3-10years)

fewLGRBs(fewyears)

fewTDEs(fewyears)

unknowns

SingleSnapshotin100sq.deg@0.1mJylevel:

op5calcounterpart,>1Gpc

Howtopulltheneedlefromthehaystackintheradio?

32

Developaprobabilis5capproachusing:- galaxycatalogs,- distancetomerger,- spa5aldistribu5onofAGNvs.NS-NSmergerwithrespecttothecenterofthegalaxies,- pre-exis5ngsurveys

e.g.,ASKAP@3mJy,50deg2,1750sources

Strategiestopulltheneedlefromthehaystackintheradio

32[Hotokezaka,Nissankeetal,2016,arXiv1605.09395,ApJ]

41.5 135.9 2.41

SNR: 9.3 SNR: 10.8

SNR: 8.8SNR: 10.4

6.1 16.7 46.8

[Nissanke,Kasliwal,Georgieva2013]

[LIGO,Virgo,advanceddesignsensi5vitynoisecurves]

[Singeretal.,arXiv:1603.07333,2016]

33

Reducefalse-posi5veratewithGWvolumes

41.5 135.9 2.41

SNR: 9.3 SNR: 10.8

SNR: 8.8SNR: 10.4

6.1 16.7 26.8

brightestgalaxiesthatproduce50%ofthelight

N_satura5on~25galaxies

Reduceastrophysicalfalseposi5vebyfactorof10-100s

[Gehrels,Canizzaro,…Nissanke+2015][Rahman,Nissanke+inprep]

SDSSGWgalaxycatalogseehips://astro.ru.nl/catalogs/sdss_gwgalcat/index.html

20152016

2017

Reducefalse-posi5veratewithGWvolumes&H-IgalaxycatalogfromSKA

34

Sta5s5calhostgalaxydemographicswithnocounterpart

[Rahman,Nissankeetal.,inprep] 35

SDSSGWgalaxycatalogseehips://astro.ru.nl/catalogs/

sdss_gwgalcat/index.html

HundredsofresolvableBHBbyspace-basedGWdetectorsbeforetheyenter

LIGO-Virgoband[Sesana2016;seealsoBreviketal.2016,Kleinetal.2016,Vitale2016]

36

November30,2016—March232017approximately48daysofHanford-Livingstoncoincidentsciencedata.

Distancereach:70Mpcfor1.4+1.4Msun,300Mpcfor10+10Msun700Mpcfor30+30Msun.

6eventcandidates,iden5fiedbyonlineanalysisusingaloosefalse-alarm-ratethresholdofonepermonth,

havebeeniden5fiedandsharedwithastronomersforEMfollowup.

Seemoreat:hip://www.ligo.org/news/index.php#O2Apr2017update

StatusofLVCsecondScienceRun

37

Immediately->SKAIera:GWdetectorsensi5vity&networkincreases=>TensofBBHmergersyr-1andfirstEM-GWdetec5ons

SKAIIera:Poten5allythousandsofcompactobjectmergersperyearatfurtherdistancewithsmallerskyerrors

Astrophysicalimplica5onsfromEM+GWcharacteriza5on:1) Constraintsfromratesandspin/massra5os:binarystellarevolu5on&BHs

throughcosmichistory;2) Natureandenvironments(circumstellar,etc…),neutronstarequa5onofstate,

internalstructure;3) CosmologicalconstraintsH0;geometryanddynamicsoflargescalestructure.4) NuclearAstrophysics:sitesofr-processelements.

Whatneedstobedoneurgently:EM+GWjointcharacteriza5on&sta5s5caltoolsrequirednow(tomakedetec5on!)Characterisa5onoftransientskiesinallwavelengths

BeyondLIGO,Virgoera:Witnesstheopeningoftheen5reGWspectrumwithCMB,PTAs,eLISA,newgenera5ongroundbaseddetectors……togetherwithnextgenera5onofwide-fieldsynop5csurveysLSST,SKA…andE-ELTs…

Theimmediatefutureisloudandbright!