GW Physics and Astronomy

京都産業大学2017/06/26

Yousuke Itoh (伊藤 洋介)KAGRA Gravitational Wave Data Analysis

International cooperation section

Research Center for the Early Universe,

the University of Tokyo

contents:

1. How to detect GWs✓Detector Basics

2. GW Astronomy✓LIGO detections and their implications

3. Other sources and future prospects

3

HOW TO DETECT GWS

Effect of a GWThe geodesic deviation equations

or schematically,

(TT)

Ԧ𝜉 = 𝑙NB: As a linear perturbation from flat space-time, Riemann curvature tensor is gauge invariant.

If you like general covariant description of effects of GW, see Koop & Finn (2014) Physical Review D, Volume 90, Issue 6, id.062002

DETECTOR BASICS

5

km-class GW detectors in the world: 2017 LIGO Hanford 4 km, desert

LIGO Livingston 4 km, forest

iKAGRA Kamioka,3 km, Michelson

undergroundVirgo Cascina 3 km

GEO 600 600 m, university farm

km-class GW detectors in the world: 2024 -aLIGO+? Hanford 4 km, desert

aLIGO+? Livingston 4 km, forest

bKAGRA Kamioka,3 km, DRFPMcryogenic,

undergroundVirgo Cascina 3 km

GEO 600 600 m, farm

LIGO India !Approved by the Indian gov. on 2016/02/162024 online??

Use a Laser interferometer to detect GWs

Interference pattern changes in time due to temporal differential change in distances due to GW

High power Laser

Mirror

Mirror

FP cavity

Beam splitter

FP cavity

A Schematic figure of an interferometric GW detector: taken from Einstein@Home web page.

It is simple, but very difficult….

9

Distance between Earth & Sun changes by about the size of Hydrogen atom.

Astrophysical GW h ~ 10-21

GW experimentalists have made it!!!

aLIGO news 2016/08

10-24

Detector performance

• Detector output time-series consists of noise n(t) (hopefully) + signal h(t)

• If noise is stationary Gaussian, it can be characterized by its (one-sided) power-spectral density Sn

• What we usually mean by “sensitivity curve” is Sn1/2 [1/Hz1/2].

11

LSC: Class.Quant.Grav. 26 (2009)

GW experimentalists have made it!!!

aLIGO news 2016/08

10-24

17

Sensitivity curve of the Ground based detectors

Lase interferometer measure distance

Joshua Smith Slide @ GWPAW2013

KAGRA: World’s first 2.5 generation GW detector

18

• Gravitational wave experiment funded mostly by the Japanese government.

• Fabry-Perot Michelson type Laser interferometer.

• Two 3km arms.• Under Kamioka mine (same site as

Super-Kamiokande), Gif pref. Japan to reduce seismic noise.

• 20 Kelvin mirror to reduce thermal noise.

Image & seismic Data from http://gwcenter.icrr.u-tokyo.ac.jp/en/

KAGRA underground

(Tokyo)

KAGRA(Kamioka)

Plot by A. Shoda et al. (JGW-G1605219-v3)

20220 km from Tokyo

Tokyo

Kyoto

KAGRA site location

KAGRA

KAGRA Collaboration

• PI: Takaaki Kajita

• Host: ICRR, Univ. of Tokyo,Co-Hosts: KEK and NAOJ

• 248 collaborators from more than 80 institutes (~

75 researchers from ~ 38 oversea univ./inst. )

•cf: LSC(+Virgo): ~ 1200(+400) researchers

• ELiTES collaboration for R&D of ET-KAGRA

• MOU with LIGO & VIRGO collaborations

MEXT New Innovative Area: “New development in astrophysics through multimessenger observations of gravitational wave sources” http://www.gw.hep.osaka-cu.ac.jp/gwastro/PI: Takashi Nakamura (2012-2016 )X-ray (N. Kawai)Optical Infrared (M. Yoshida)Neutrino (M. Vagins)GW data analysis (N. Kanda)Theory (T. Tanaka)

2222222222

Mozumi

New Atotsu

Super

Kamiokande

CLIO (100 m)

Map of KAGRA site (Kamioka mine)

X armY arm

2323232323

Photos of the KAGRA site

Photo courtesy: N. Kanda, S. Miyoki, K. Yamamoto

KAGRA status

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1000 t/h water flow by snow melting (April)

man power for snow shoveling (Winter)

bear threats avoidance by loud music (Autumn/Spring)

• iKAGRA finishes successfully• simple Michelson• stable data transfer, basic calibration• data analysis now undertaken

• bKAGRA: Cryogenic-DRFPM (2018-).• Some issues: (other than money & manpower)

Characteristic GW freq.

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NB: Visible light frequency: 400THz〜800THz

GW freq. is audible.

Multi-frequency GW Science

C. Moore R. Cole, & C. Berryhttp://www.ast.cam.ac.uk/~rhc26/sources/

Multi-frequency GW Science

C. Moore R. Cole, & C. Berryhttp://www.ast.cam.ac.uk/~rhc26/sources/

GW ASTRONOMY

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29

GW????

All sky maps:Neutrino (Icecube)

Gamma-Ray >100MeV (CGRO, NASA)

X-Ray 0.25, 0.75, 1.5 keV (S. Digel et. al. GSFC, ROSAT, NASA)

Infrared (DIRBE Team, COBE, NASA)

Gamma-Ray (N. Gehrels et.al. GSFC, EGRET, NASA)

Ultraviolet (J. Bonnell et.al.(GSFC), NASA)

Radio 1420MHz (J. Dickey et.al. UMn. NRAO SkyView)

X-Ray 2-10keV (HEAO-1, NASA)

Visible (Axel Mellinger)

Radio 408MHz (C. Haslam et al., MPIfR, SkyView)

http://www.ipac.caltech.edu/outreach/Multiwave/gallery3.html

SNe, GRBs in local universe.

NS/NS binaries coalescence within ~ 200 Mpc. Stellermass BH/BHwithin ~ 1Gpc.

Nearby pulsars in Milkyway

Gravitational Wave sources for KAGRA/LIGO/VIRGO

Stochastic backgroundProbably not primordial one.

Images are taken from NASA and hubblesite.

Expected NS/NS event rate for aLIGO0.1 events in O1

N

2015/9-2016/01

2018?

2016 Q4-2017

M. Landry‘s slide

32

33

TITLE: GCN CIRCULAR

NUMBER: 18330

SUBJECT: LIGO/Virgo G184098: Burst candidate in LIGO engineering

run data

Dear colleagues,

We would like to bring to your attention a trigger identified by

the online Burst analysis during the ongoing Engineering Run 8

(ER8).

2days

2015-09-14

09:50:45 UTC

2015-09-16

06:39 UTC

GCN circular (access restricted at first)

3mins

ER8 configuration:(50 sec./a few min in O1)1.3

Gyr

34

TITLE: GCN CIRCULAR

NUMBER: 18330

SUBJECT: LIGO/Virgo G184098: Burst candidate in LIGO engineering

run data

Dear colleagues,

We would like to bring to your attention a trigger identified by

the online Burst analysis during the ongoing Engineering Run 8

(ER8).

2days

2015-09-14

09:50:45 UTC

2015-09-16

06:39 UTC

実際に流れた速報（MOU締結者のみ閲覧可）

3mins

1.3Gyr

ApJL 826:L13 2016

ER8 configuration:(50 sec./a few min in O1)

35

Citation history: 1023 refereed since the press release 2016/02/11

data retrieved on 2017 June 25.

Move from BNS to BBH

36

BNS subgroup after the discoveryBBH subgroup after the discovery

GW detection

37

LSC-Virgo, PRL 116, 061102 (2016)

Data analysis

38

Detector output time series

Detector power spectrum：Huge power in low frequencies ✓ High-pass filter (typ. Hann)✓ Whitening ✓ Line noise notch filter

Reconstructed GW

Same????

39

GW151226

Data analysis

40

Reconstructed GW

Want to extract physical informationCompute correlation with theoretical expectationFind the model that maximizes the correlation

Theoretical expectations

compare

41

Luminosity distance, sky location ,masses, spin angular momentums of the black holes of the binary

!n

What we can learn

42

Luminosity distance, sky location ,masses, spin angular momentums of the black holes of the binary

!n

What we can learn

43

Luminosity distance, sky location ,masses, spin angular momentums of the black holes of the binary

!n

What we can learn

44

Numerical Relativity： Merger of two black holesWhat happened to event horizons?How much energy was radiated?

What we can learn

45

Mass (M), spin angular momentum (a) of the final black hole.Kerr-ness: Test of GR

What we can learn

Localization

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~ 600 square degrees for GW150914

LIGO Scientific Collaboration and Virgo Collaboration PHYS. REV. X 6, 041015 (2016)

Localization

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~ 600 square degrees for GW150914

LIGO Scientific Collaboration and Virgo Collaboration PHYS. REV. X 6, 041015 (2016)

cf. galaxy density: 0.02 L10 /Mpc3

(Kopparapu et. al. ApJ. 2008)The number of galaxies in an observable volume(horizon distance 200Mpc) in (10)2 square degrees is O(10000).

100

1101 1000.1

10

time resolution (s)

FO

V (

sq

. d

eg.)

HSC

SDSS

22

CCD

Pan-STARR

Decam

22

20

25

23

iPTF

circle size: limiting magnitude

Follow-up: time resolution & FOV

Tomoe-Gozen

CMOS

15

1917

Gamma-ray detection by Fermi GBM

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✓ 0.4sec after GW150914✓ False alarm probability

0.002✓ 1sec flash: SGRB? ✓ 2 x 1049 erg s-1 @410Mpc

• one order dimmer?✓ If SGRB we should find 10

events akin to GW150914 .✓ NO detection by

INTEGRAL/SWIFT

✓ Connaughton et al. 2016, ApJL, 826:L6

✓ See also Greiner et al. ApJ827:L38 (2016)

< 3σ event

Neutrino follow-up

50

ANTARES Collaboration, IceCube Collaboration, LIGO Scientific Collaboration, and Virgo CollaborationPHYSICAL REVIEW D 93, 122010 (2016)

+-500 sec window

IceCube 3 events: consistent with atmospheric background.

Masses

51

timescale: (1+z)M: Cannot determine redshift independently for BBH.

LV PRX6 0401015 (2016)

Final BH Mass and spin

52

Relatively well-determined Determination from X-ray obsmay be controversial.

LV PRX6 0401015 (2016)

Correlation between Distance & inclination

53

• Strong correlation between the orbital inclination and distance.• Spins not well determined.• Template for general configuration (misaligned spins, eccentricity > 0.1) unavailable

LV PRX6 0401015 (2016)LV, PRL 116, 241102 (2016)

Spins

54

• Strong correlation between the orbital inclination and distance.• Spins not well determined.• Template for general configuration (misaligned spins, eccentricity > 0.1) unavailable

Individual spin not determined well: spins appear at higher PN orders.

LV PRX6 0401015 (2016)

Test of GR

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• Parameters from Inspiral and post-inspiral are consistent.

• No deviation from GR found

Progenitor

http://ligo.org/science/Publication-GW150914Astro/index.php

✓ Unknown

✓ may have much smaller metalicity

too much metals:(a) interstellar gas cools

• cloud splits into small pieces

• small stars form(b) Large opacity

• Large stellar wind• Large mass loss

✓ May be Pop III ?? (Kinugawa et al. 2014)✓ B-DECIGO science target

ASTROPHYSICAL IMPLICATIONS

57

ASTROPHYSICAL IMPLICATIONS OF THE BINARY

BLACK-HOLE MERGER GW150914• Facts：

– Existence of BH with mass larger than 25 Msun

– Nearly equal mass

– Small spin or aligned spin

– Event rate: 2-53 (400) Gpc-3 yr-1

• Two scenario

– Isolated BBH in galactic fields: isolated scenario (Childhood friend scenario)

– Young and/or old dense stellar environments: dynamical scenario (Matchmaking party scenario)

• Suggestions

– Mass indicates low metalicity: Z < 0.5 Zsun

• From old universe or low mass (low metal) galaxy

– Could not distinguish two scenarios

• Spin measurement– orbital angular momentum does not need to

align with BH spins in dynamical scenario

– Could not constrain from the GW observation.

• Eccentricity– Eccentricity would be large in dynamical

scenario

– But we cannot determine e if e < 0.1

– Eccentricity is always small in the aLIGO band

distinguish two scenarios

Redshift distribution and B-DECIGO?

nakamura et al. 1607.00897

“Pre-DECIGO” is now called “B-DECIGO”.geocentric orbit

Redshift distribution and “B-DECIGO”?

nakamura et al. 1607.00897

With “B-DECIGO”, we can distinguish three scenarios: PoP III, Pop I/II, and PBBH

“B-DECIGO” forecasts

62

Prediction for KAGRA, aLIGO, & Virgo and other follow-up teams

nakamura et al. Prog Theor Exp Phys (2016)See also A. Sesana PRL 116, 231102 (2016)

FUTURE & OTHER SOURCES

63

Some questions• test of GR

– velocity of GW– polarizations of GW– exotic compact objects: QNM, tidal deformability– Kerr-ness: QNM, quadrupole moment (KLV, EMRI by eLISA)– extra dimensions???

• Cosmology– Inflation (CMB B-mode, direct detection by Ultimate-

DECIGO?)– Large scale structure with different method other than EM– gravitational lensing of gravitational wave– Primordial BH– Dark matter search– cosmic strings– phase transition

Some questions• Nuclear physics

– hyperon puzzle: tidal disruption/deformability, mass-radius – site of r-process elements generation: SGRB/SNe? – quark stars: (continuous wave)

• Astrophysics– origins (or evolution scenario) of SMBH [eLISA/PTA]– existence of SMBH binaries (Last 1 parsec problem) [PTA]– existence of IMBHs– verification binaries [eLISA]– BHB as a smoking gun of Pop III– SGRB: NS/NS or NS/BH?– Supernovae mechanism: neutrino, rotation– Supernovae: what will be left? BH or NS?– pulsar glitch– stellar oscillation [KLV high-f]– pulsar precession: Is it possible? (too low frequency … ?)

First detection made. It’s over?• Undergraduate student asked me this.

• Neutrino (astro-)physics over after its discovery?

– Solar neutrino, 1987A, oscillation, high-energy neutrino, …

• Radio astronomy ended in 1930s?

– Pulsar, Quasar, CMB, AGN, ….

• X-ray, gamma-ray, infrared astronomy ….?

• It’s difficult to predict what’s next, though.

66

Prospects based on real events

67

Roughly, 1/(0.83Gpc3 16/365 yr) ~ 45 events/Gpc3/yr

O2: 2016/11-2017/0x- (with Virgo), 6 triggers shared with MOU-signing astronomers [May 3 News by LSC].LV. Astrophys.J. 833 (2016)

LIGO+ Plan and prospects

68Report from the DAWN-II Workshop, Atlanta, GA, July 7-8, 2016

Future plans

69

KNAW-agenda:Einstein Telescope

Why KAGRA useful in 2018?

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CBC/Burst Search: we do not know when it visits us.

✓ We need as many detectors as possible that are actually running.✓ Underground is ideal place (low seismic noise)

Importance is in not only the sensitivity & localization, but also in the duty cycle.

Duty cycle in O1 LHO (windy desert) VIRGO (VSR2/4) 80%LLO (forestry) KAGRA (expected) 80%33 % coincidence

Angular resolution (90 % CL)

71

2016-2017 @80Mpc

2017-2018 @80Mpc

2022+ @160Mpc

2019+ @160Mpc

Virgo plans to join the LSC O2b from 2017 March.Need more to find number of polarizations!!!

Arxiv: 1304.0670

BNS/NS-BH

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EOS can be determined by how NS/NS are tidally disrupted?

Takami, Rezzolla & Baiotti, PRL 113, 091104 (2014)

74

EOS can be determined by how NS/NS are tidally disrupted?

Takami, Rezzolla & Baiotti, PRL 113, 091104 (2014)

r-process elements by NS/NS

75Goriely et al., Astrophysical Journal Letters, 738:L32, 2011

Detection prospects

76Rosswog et al. (2017) CQG 34 104001

Follow up

77M. Tanaka, Adv.Astron. 2016 (2016) 6341974

SUPERNOVAE

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Detectable if within Milkyway?

79

Powell et al.. arxiv 1610.05573v3

But numerical simulation is difficult….(had never exploded until recently).

STOCHASTIC GW

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Stochastic foreground

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O5 (2022?) science

LV, Phys. Rev. Lett. 116, 131102

Stochastic GW

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O5 (2022?) scienceObstacles to inflationary GWs?

LV PRL 118, 121101 (2017)See also Callister et al. arxiv:1704.08373v1 for test of

GR using SGW.

CONTINUOUS WAVES

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Continuous GW sources

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GW from spinning motion of NS.

Image credit: Einstein@Home

Stability of stellar rotation means simple waveform (with some exceptions…)

It’s so weak that Tobs ~ yearsis necessary.

- Degree of non-axisymmetry

- “Height of a mountain” in some sense(Johnson-McDaniel PRD 2013)

What we can learn

85

Amplitude of GW or “degree of non-axisymmetry ε” of NS

86

Calculations ontheoretical maximum(Johnson-McDaniel PRD 2013 & Johnson-McDaniel & Owen, PRD 2013 )

GR-SLy EOS

GR-LKR1 EOS

LKR1SLy

“known pulsar search”

• “known” in advance by electromagnetic observation:

– frequency, frequency derivative

– source direction

– phase

87

LV Upper limits on h0 vs GW frequency

88

Vela & Crab Spin-down upperlimit

LV ApJ 839:12 (2017)

10-23

10-26

100 Hz 1kHz

LV-UL distributions of ε & h0

89

LV ApJ 839:12 (2017)

Advanced Detectors’ Future prospects & Theoretical expectation

90Pitkin PRD 2011

Necessary Quadrupolemoments to detect known PSRs.

Black: GC-PSRs assumingfiducial spin-down.

• CCS: Hybrid Crystalline Color-superconducting Star

• SSS: Solid Strange Star• NNS: Normal Neutron

Star• HS: Hybrid Star (charged

meson condensate + quark-baryon core)

Ad. Detectors’ Future prospects

91Pitkin PRD 2011

Maximum possible Q22

Q22 ~ 1033 kg m2

(Johnson-McDaniel & Owen PRD 2013)

SKA might find 1000 more millisecond PSRs, so we have 5 times more than the left table…?

“unknown pulsar search”

• “unknown” in advance by electromagnetic observation:

– frequency, frequency derivative

– source direction

– phase

92

93

I see a pulsar, wow

I don’t seen any EM, huh?

94

I see a pulsar, wow

I see GW from something!

GW

Blandford-Cutler argument

• There are neutron stars that solely loses their spin rotation energies via emission of GWs

• Those neutron stars are distributed randomly within the Galactic disk with radius RG

• Such neutron stars are born every years.

• The maximum possible strain amplitude if searched for [fmin,fmax] is:

• or 10-24

𝜏𝑏 = 30

96

Gholami, Cutler, Krishnan (2005)

“Binary pulsar search”

97

Known accreting pulsar search: better case scenario

98

• Multi templates search only “look-elsewhere” effect is taken into account.

• 2 years integration• quadrupole mode• long-term average flux• Perfect balance • Open: frequency not known for

sure.• No limitation on computing power• SCO-X1 is marginally detectable.

Watts et al. (2008)

First detection made. It’s over?

• Undergraduate student asked me this.

• Neutrino (astro-)physics over after its discovery?

– Solar neutrino, 1987A, oscillation, high-energy neutrino, …

• Radio astronomy ended in 1930s?

–Pulsar, Quasar, CMB, AGN, ….

• X-ray, gamma-ray, infrared astronomy ….?

•No! Not at all! It has just begun. 99

Summary today

• First detection made by LIGO, more to come– Expect High ER: ~ 1 event/day in 202x (O5) – “Big(?)data ”: 300k channels, 1PB/yr

• Known unknowns are waiting–NS/NS, NS/BH, pulsars, stochastic foreground, SNe, sGRB,

IMBHs, SMBHs, cosmic strings, exotic objects– test of GR in truly strong field regime

• Are there unknown unknowns?

100