JGW-G2012028-v1

ILC Summer Camp 2020

Gravitational-wave Observation and KAGRA

Masaki Ando (Univ. of Tokyo) on behalf of the KAGRA collaboration

ILC Summer Camp 2020 (Sep 24, 2020, Online) Presentation Plan

・Observation of Gravitational Waves ・KAGRA

ILC Summer Camp 2020 (Sep 24, 2020, Online) Observation of GW

ILC Summer Camp 2020 (Sep 24, 2020, Online)

Rapid motion of mass will cause ripples of space time, which propagate at the . Gravitational Wave

Illustration : KAGAYA

ILC Summer Camp 2020 (Sep 24, 2020, Online) Effect of GW

Gravitational Wave Effect of GW : Change in the proper distance z between separated masses.

Amplitude of GW is y described by strain ‘ℎ’ .

ℎ ~ 훿퐿 / 퐿 퐿 훿퐿 : Change in distance x : Original separation

ILC Summer Camp 2020 (Sep 24, 2020, Online) Principle of GW Antenna

Binary inspiral Laser Interferometer (Michelson Interferometer) GWs

GW will cause differential length change in two arms

Beam splitter Diff. change GW is observed from the Interference light-power change on Laser source the photo detector. Photo detector GW signal

ILC Summer Camp 2020 (Sep 24, 2020, Online) First Detection of GW

・On Feb. 11th, 2016, LIGO announced first detection of gravitational wave. The signal was from inspiral and merger of binary black hole. Opens a new field of ‘GW astronomy’.

Courtesy Caltech/MIT/LIGO Laboratory

ILC Summer Camp 2020 (Sep 24, 2020, Online) Mergers of Binary Black Hole

・Publications after the first event. arXiv:1811.12907 (Nov. 30, 2018) *2nd: GW151226 (reported in 2016.6) *3rd: GW170104 (reported on 2017.6.2) *4th: GW170814 (reported on 2017.9.27) *5th: GW170608 (reported on 2017.11.15) *6-10th: GW151012, GW170729, GW170809, GW170818, GW170823 (reported on 2018.11.30)

LIGO/VIRGO GWTC-1 [Phys. Rev. X 9, 031040, (2019) ] 3 BBH events in O1 (Sept. 2015 – Jan. 2016) 7 BBH events in O2 (Nov. 2016 – Aug. 2017)

・56 Public alerts in O3 (April 2019 – Mar. 2020)

 BBH mergers are common events in the universe.

ILC Summer Camp 2020 (Sep 24, 2020, Online) Merger of Binary Neutron Stars

・On Oct.16th, 2017, LIGO-VIRGO collaboration announced the first detection of gravitational-wave signal from merger of binary neutron stars

・The signal was detected on August 17th, 2017.  Named GW170817. ・Source Localization ~30deg2

Courtesy Caltech/MIT/LIGO Laboratory

ILC Summer Camp 2020 (Sep 24, 2020, Online) EM Follow-up Observations

・Detection by Advanced LIGO: SNR of 32.4. ・Advanced Virgo contribution for sky localization: from 190 deg2 to 30 deg2 .

ApJL 848 L12 (2017) ・Prompt EM (gamma-ray) observation by Fermi, 1.7sec after GW. ・Obs. by ~70 EM telescopes. EM counterpart was detected by X-ray, UV, Optical, IR, and Radio.

ILC Summer Camp 2020 (Sep 24, 2020, Online) Discovery of the EM Counterpart

Credit: Sarah Wilkinson / LCO (Taken from https://youtu.be/wnwMhvdDcfI)

ILC Summer Camp 2020 (Sep 24, 2020, Online) ・EM counterpart was observed for the first time in GW170817.

・New knowledge * Origin of SGRB. * Origin of heavy elements in the universe. * EoS of * Fundamental physics and cosmology: speed of GW, Hubble’s constant, ….

ApJL 848 L12 (2017)

ILC Summer Camp 2020 (Sep 24, 2020, Online) Fundamental Physics: Speed of GW

・Test of GR : Propagation speed of GW. ・GW (GW170817) and EM (GRB170817A) from the same BNS merger * False coincidence rate (direction and time): 5 × 10−8 * Arrival time difference 1.74 ± 0.05 sec * Source distance : 40Mpc (1.2x1024 m).

 Stringent limit on the speed of GW 푣 −3 × 10−15 ≤ GW − 1 ≤ 7 × 10−16. 푣EM

※ Note: Dependent on GRB source model. Here, GW and EM radiation-time difference is assumed to be less than 10 sec from the source. There are more exotic models, which will be tested by more events to be observed.

ILC Summer Camp 2020 (Sep 24, 2020, Online) Fundamental Physics

・Cosmological Parameter Hubble parameter by Use BNS merger as a ‘Standard Siren’ CMB measurement (Planck): 퐻0 = 67.90 ± 0.55 km/s/Mpc - GW amplitude  Source distance. - EM counter part  Hubble parameter: +12.0 퐻0 = 70−8.0 km/s/Mpc Consistent with other results.

Independent measurement. doi:10.1038/nature24471

※ Update using BBH results +14.0 Hubble parameter: 퐻0 = 68−7.0 km/s/Mpc [ arXiv:1908.06060v2 (Aug. 2019) ]

ILC Summer Camp 2020 (Sep 24, 2020, Online) NS EoS: Tidal deformability

・Tidal deformation in formation from GW waveform

* Tidal deformability 휆 :

푄푖푗 = −휆퐸푖푗

Quadrupole Tidal force from moment companion object * Dimensionless parameter 퐺 퐺푀 Λ = 휆, 퐶 = 퐶5푅5 푐2푅

Hard EoS  Large diameter  Large Λ

ILC Summer Camp 2020 (Sep 24, 2020, Online) Observation Runs

[ LIGO G2001426-v2 (2020) ]

ILC Summer Camp 2020 (Sep 24, 2020, Online) Detection Papers from O3

・GW190425 : BNS with large .

Component mass of 1.12 − 2.52 푀⊙ [ ApJ. Letters 892 L3 (2020) ] +0.12 ・GW190412 : BBH with large mass ratio of 0.28−0.06 Evidence of higher-multipole emission [ arxiv.org/abs/2004.08342, Accepted by PRD on June 30, 2020 ] ・GW190814 : ‘Mass gap’ event Most unequal mass +0.008 ratio of 0.112−0.009

( ~23.2 푀⊙ and ~2.59 푀⊙) The nature (BH or NS) of the secondary is unknown. [ ApJ. Letters 896:L44 (2020) ]

ILC Summer Camp 2020 (Sep 24, 2020, Online) Detection Papers from O3

・GW190521 : BBH with total mass of 150 푀⊙

Component mass of 85푀⊙ − 66푀⊙ [ PRL 125 101102 (2020) ] Primary BH lies within the ‘gap’ mass for process.

Remnant is 142푀⊙ can be considered an IMBH.

[ LIGO G2001426-v2 (2020) ] ILC Summer Camp 2020 (Sep 24, 2020, Online) KAGRA (かぐら)

- Ground-based GW antenna in Japan-

ILC Summer Camp 2020 (Sep 24, 2020, Online) KAGRA

KAGRA (かぐら) 2nd generation GW Antenna. in Japan LCGT (Large-scale Cryogenic Gravitational-wave Telescope)

Project started in 2010, >300 Collaborators, from >100 Groups in 14 Regions

ILC Summer Camp 2020 (Sep 24, 2020, Online) KAGRA Site

Underground site at Kamioka, Gifu prefecture Facility of the Institute of Cosmic-Ray Research (ICRR), Univ. of Tokyo.

Underground Research Facility <1hour by car from Toyama Neutrino : SK, Kamland city or Toyama airport Dark matter : XMASS Gravitational Wave : CLIO, KAGRA Geophysics : Strain meter

Kamioka

Tokyo Osaka

Map by Google

ILC Summer Camp 2020 (Sep 24, 2020, Online) International GW Network

International network by 2nd–gen GW antennae.  GW astronomy (Detection, Parameter estimation, …)

aLIGO (USA) 4km x 2

140 100 KAGRA (JPN) 20 20 baseline 3km

GEO-HF (GER-UK) Adv.VIRGO (ITA-FRA) LIGO-India baseline 600m baseline 3km project approved

ILC Summer Camp 2020 (Sep 24, 2020, Online) Sensitivity Comparison

KAGRA

ILC Summer Camp 2020 (Sep 24, 2020, Online) Comparison of 2nd Generation IFOs

2nd-generation detectors 3rd generation aLIGO Ad. VIRGO KAGRA ET

Observation ~ 2015 ~ 2017 ~ 2020 ~ 2030

Surface Surface Underground Underground Site Hanford, Pisa Kamioka 3 IFOs Livingstone (India)

Baseline 4 km 3 km 3 km 10 km Obs. Range(*1) 306 Mpc 243 Mpc 237 Mpc (*2) 3 Gpc

IFO config. Broadband RSE Detuned RSE RSE RSE (Variable tuning) Xylophone TN reduction Large beam, Low mech-loss mirror, Thermal compensation Cryogenic Cryogenic 1st stage VIS Active Passive Passive Passive

(*1) Obs. Range for NS-NS binary mergers, Optimal direction and polarization, SNR>8. (*2) Number may be changed.

ILC Summer Camp 2020 (Sep 24, 2020, Online) International Network for Astronomy

Animation : S. Kawamura (ICRR)

Multiple Detector

Identify the source by the arrival-time difference

ILC Summer Camp 2020 (Sep 24, 2020, Online) Sky Localization

H: LIGO-‐Hanford L: LIGO-‐Livingston V: Virgo, K: KAGRA I: LIGO-Indea

From presentation by H. Tagoshi J.Veitch+, PRD85, 104045 (2012) Tagoshi+ (2014)

S.Fairhaurst CQG 28(2011) 105021

Adding KAGRA to the network (aLIGO + adv. VIRGO)  Improvement of angular resolution by 3-4 times.

ILC Summer Camp 2020 (Sep 24, 2020, Online) KAGRA GW Detector

・KAGRA as a 2nd generation GW detector

Large-scale Detector - Baseline : 3km - Intra-cavity power ~400kW Cryogenic interferometer - Mirror temperature: 20K Underground site : - 1000m underground at Kamioka, Gifu

* International GW network with LIGO/VIRGO * Advanced technologies: cryogenic and underground

ILC Summer Camp 2020 (Sep 24, 2020, Online) KAGRA Configuration

Input/Output Optics - Beam Cleaning and stab. Main Interferometer ETM - Modulator, Isolator - 3 km arm cavities - Fixed pre-mode cleaner - RSE with power recycling - Suspended mode cleaner DC readout scheme Length 26 m, Finesse 500 - Cryogenic test masses

arm cavity arm Sapphire, 20K -

- Output MC Y ‘Type-A’ vibration isolator - Photo detector Cryostat + Cryo-cooler

ITM - Room-temp. Core optics (BS, PRM, SEM, …)

Power Input 78 W PRM 800 W BS ITM ETM ~180 W Bench Power ~380 kW

Laser 26-m MC Power-recycling X-arm cavity Gain ~11 Length 3,000 m Finesse 1,530 Laser Source RSE: (Resonant - Wavelength 1064 nm sideband Extraction) Signal-band Gain ~15 - Output power 180 W SEM Detuned RSE High-power MOPA (Variable tuning)

ILC Summer Camp 2020 (Sep 24, 2020, Online) KAGRA Photo

3-km Tunnel and Beam Duct (Photo by S. Miyoki)

ILC Summer Camp 2020 (Sep 24, 2020, Online) KAGRA Photos

Vibration Isolation

ILC Summer Camp 2020 (Sep 24, 2020, Online) KAGRA Photos

Cryogenic Suspension

ILC Summer Camp 2020 (Sep 24, 2020, Online) KAGRA Photo

Photo and CG model of cryogenic payload

ILC Summer Camp 2020 (Sep 24, 2020, Online) KAGRA Photos

Sapphire Mirror: Diameter 22cm, Thickness 15cm

ILC Summer Camp 2020 (Sep 24, 2020, Online) KAGRA Observation Run

・KAGRA started observation run in 2019 * KAGRA solo : 2 weeks (Feb. 25 – Mar. 10) * O3GK : 2 weeks (Apr. 7 – Apr. 21) * Science-mode duty factor 54% * Typical binary range ~500 kpc (Best ~970 kpc)

From KAGRA web site (Feb 25, 2020) From presentation by T.Kajita (May 27, 2020) ※ BNS range here: sky averaged range

ILC Summer Camp 2020 (Sep 24, 2020, Online) KAGRA Observation Run

・KAGRA started observation run in 2019 * KAGRA solo : 2 weeks (Feb. 25 – Mar. 10) * O3GK : 2 weeks (Apr. 7 – Apr. 21)

From presentation at JPS meeting by T. Yamamoto (Sep 14-17, 2020) ※ BNS range here: sky averaged range

ILC Summer Camp 2020 (Sep 24, 2020, Online) Observation Scenario

3 BBHs

7 BBHs 1 BNS

>50 public alerts Today

Living Reviews in Relativity 21, 3 (2018); Updated version to be submitted.

ILC Summer Camp 2020 (Sep 24, 2020, Online) Summary

ILC Summer Camp 2020 (Sep 24, 2020, Online) Summary

・First direct detection of GW was achieved by LIGO 100 years after the theoretical prediction by A. Einstein by . ・It opens the new field of ‘Gravitational-wave astronomy’. We obtained a new prove to understand the universe. ・KAGRA started observation run in 2020. LIGO-VIRGO-KAGRA network will be formed in O4.

ILC Summer Camp 2020 (Sep 24, 2020, Online) End

ILC Summer Camp 2020 (Sep 24, 2020, Online)