GWs from neutron star mergers: accuracy and tidal effects S. - - PowerPoint PPT Presentation

▶
gws from neutron star mergers accuracy and tidal effects
SMART_READER_LITE
LIVE PREVIEW

GWs from neutron star mergers: accuracy and tidal effects S. - - PowerPoint PPT Presentation

Dec 16, 2022 191 likes •479 views

GWs from neutron star mergers: accuracy and tidal effects S. Bernuzzi TPI-FSU Jena / SFB-TR7 A.Nagar (IHES) M.Thierfelder (Jena), B.Bruegmann (Jena) SB, MT & BB, PRD 85 104030 (2012) SB, AN, MT & BB, [gr-qc] arxiv:1205.340 (2012)

slide-1
SLIDE 1

GWs from neutron star mergers: accuracy and tidal effects

  • S. Bernuzzi

TPI-FSU Jena / SFB-TR7

SB, MT & BB, PRD 85 104030 (2012) SB, AN, MT & BB, [gr-qc] arxiv:1205.340 (2012)

A.Nagar (IHES) M.Thierfelder (Jena), B.Bruegmann (Jena)

lunedì 28 maggio 2012

slide-2
SLIDE 2

Motivations

PN NR

lunedì 28 maggio 2012

slide-3
SLIDE 3

Motivations

PN NR

SNR~35 Stiff EOS 68%

[Hinderer et al (2010)]

lunedì 28 maggio 2012

slide-4
SLIDE 4

Motivations

PN NR

SNR~35 Stiff EOS 68%

[Hinderer et al (2010)]

SNR~16 EOS M>1.97 95%

[Damour et al (2012)]

lunedì 28 maggio 2012

slide-5
SLIDE 5

Motivations

PN NR

SNR~35 Stiff EOS 68%

[Hinderer et al (2010)]

SNR~16 EOS M>1.97 95%

[Damour et al (2012)]

e.g. [Bauswein et al (2012)]

lunedì 28 maggio 2012

slide-6
SLIDE 6

S.Bernuzzi - Tobemory, May 28th 2012

Questions

f 450 Hz ⇒ last 10 orbits ⇒ NR regime!

lunedì 28 maggio 2012

slide-7
SLIDE 7

S.Bernuzzi - Tobemory, May 28th 2012

Questions

  • Validity/Accuracy of analytic models (PN/EOB) and templates ?

f 450 Hz ⇒ last 10 orbits ⇒ NR regime!

lunedì 28 maggio 2012

slide-8
SLIDE 8

S.Bernuzzi - Tobemory, May 28th 2012

Questions

  • Validity/Accuracy of analytic models (PN/EOB) and templates ?

f 450 Hz ⇒ last 10 orbits ⇒ NR regime!

[Bini et al (2012)]

α(2)

2

= 85/14 α(3)

2

= 257/48 40 αeff

2

100

[Baiotti et al (2011)]

Atidal

EOB(u) = 4

  • ℓ=2

−κT

ℓ u2(ℓ+1)

1 + α(ℓ)

1 u + α(ℓ) 2 u2 + ...

  • lunedì 28 maggio 2012
slide-9
SLIDE 9

S.Bernuzzi - Tobemory, May 28th 2012

Questions

  • Validity/Accuracy of analytic models (PN/EOB) and templates ?

f 450 Hz ⇒ last 10 orbits ⇒ NR regime!

[Bini et al (2012)]

α(2)

2

= 85/14 α(3)

2

= 257/48 40 αeff

2

100

[Baiotti et al (2011)]

Atidal

EOB(u) = 4

  • ℓ=2

−κT

ℓ u2(ℓ+1)

1 + α(ℓ)

1 u + α(ℓ) 2 u2 + ...

  • Can we extract this info reliably from NR simulations ? Are

simulations accurate enough ?

lunedì 28 maggio 2012

slide-10
SLIDE 10

S.Bernuzzi - Tobemory, May 28th 2012

Full GR Framework

  • BAM matter code
  • Moving boxes technique+

Berger-Oliger

  • MoL with Runge-Kutta

schemes and

  • HRSC:
  • Primitive reconstruction
  • LLF flux scheme

[M. Thierfelder, SB & B.Bruegmann (2011)]

  • Free evolutions 3+1 NR
  • Einstein: BSSNOK / Z4C
  • Moving puncture gauge
  • Psi4 GW extraction
  • ideal GRHD
  • ideal gas EoS (Isentropic flow)
  • No magnetic fields - microphysics

lunedì 28 maggio 2012

slide-11
SLIDE 11

Dynamics and GWs: 9 orbits

lunedì 28 maggio 2012

slide-12
SLIDE 12

Dynamics and GWs: 9 orbits

lunedì 28 maggio 2012

slide-13
SLIDE 13

Dynamics and GWs: 9 orbits

Several runs!

lunedì 28 maggio 2012

slide-14
SLIDE 14

“Contact” & “Merger”

lunedì 28 maggio 2012

slide-15
SLIDE 15

S.Bernuzzi - Tobemory, May 28th 2012

Waveform uncertainties

  • Self-convergence: 2nd order (do not shift !) up to GW

frequencies 0.07/M

  • Extrapolation of waveform in resolution (Richardson, several

runs) ⟹ best case: Δφ~ 0.13 rad andΔA/A~ 0.2 % (0.07/M)

  • Finite radius extraction must be taken into account

Mω22 < 0.07 Mω22 < 0.1

[SB, M. Thierfelder & B.Bruegmann (2012)]

lunedì 28 maggio 2012

slide-16
SLIDE 16

S.Bernuzzi - Tobemory, May 28th 2012

NR Vs PN - 9 orbits - CENO data

T4 3.5PN + NLO

lunedì 28 maggio 2012

slide-17
SLIDE 17

S.Bernuzzi - Tobemory, May 28th 2012

NR Vs PN - 9 orbits - CENO data

T4 3.5PN + NLO

lunedì 28 maggio 2012

slide-18
SLIDE 18

S.Bernuzzi - Tobemory, May 28th 2012

NR Vs PN - 9 orbits - CENO data

T4 3.5PN + NLO

lunedì 28 maggio 2012

slide-19
SLIDE 19

S.Bernuzzi - Tobemory, May 28th 2012

⇒ significant dephasing due to tidal effects contribute

during the last 6-9 orbits ... higher-order (>1PN) tidal effects? amplification?

NR Vs PN - 9 orbits - CENO data

T4 3.5PN + NLO

lunedì 28 maggio 2012

slide-20
SLIDE 20

S.Bernuzzi - Tobemory, May 28th 2012

Systematic uncertainties

  • Numerical viscosity of the HRSC scheme
  • Effect of different grid configurations (Berger-Oliger, ...)
  • Gauge effects on numerically extracted waves
  • Spurious thermal effect during inspiral
  • ...

They all potentially contribute (~ same order of magnitude), slowly improve with resolution - larger grids (≲ 2nd or 1/r converging behaviour),

  • nly partially under control !

[M. Thierfelder, SB & B.Bruegmann (2011) L.Baiotti, B.Giacomazzo & L.Rezzolla, CQG (2008)]

lunedì 28 maggio 2012

slide-21
SLIDE 21

S.Bernuzzi - Tobemory, May 28th 2012

Numerical “viscosity”/“dissipation” - 3 orbits

Resolution effect Reconstruction effect

Prompt collapse/delayed collapse ?

lunedì 28 maggio 2012

slide-22
SLIDE 22

9 orbits: changing setup ...

lunedì 28 maggio 2012

slide-23
SLIDE 23

9 orbits: changing setup ...

longer inspiral: phasing!

lunedì 28 maggio 2012

slide-24
SLIDE 24

9 orbits: changing setup ...

longer inspiral: phasing!

3.5 3.6 3.7 3.8 3.9 4 4.1 4.2 4.3 !0.065 !0.06 !0.055 !0.05 !0.045 !0.04 !0.035 !0.03

j E

3PN (point mass) EOB (point!mass) RK3+LLF+CENO3 RK4+LLF+WENOZ

4.215 4.22 4.225 4.23 4.235 4.24 !0.0332 !0.0331 !0.033 !0.0329 !0.0328 !0.0327 !0.0326 !0.0325 !0.0324 lunedì 28 maggio 2012

slide-25
SLIDE 25

NR Vs PN/EOB - 9 orbits - WENO data

500 1000 1500 2000 !1.2 !1 !0.8 !0.6 !0.4 !0.2 0.2 0.4

u/M φX

22-φNR 22 WENO uncertainty EOB (point-mass) EOB tidal LO EOB tidal 2PN α(2)

2

= 85/14 EOB tidal 2PNeff ¯ α2 = 20 EOB tidal 2PNeff ¯ α2 = 40 T4 tidal LO

lunedì 28 maggio 2012

slide-26
SLIDE 26

500 1000 1500 2000 2500 0.05 0.1 0.15 0.2 0.25

u/M Mω22

2200 2250 2300 2350 2400 2450 2500 2550 2600 2650 2700 0.05 0.1 0.15 0.2 0.25

EOB (point-mass) EOB tidal LO EOB tidal 2PN α(2)

2

= 85/14 T4 tidal LO WENO (H)

500 1000 1500 2000 2500 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

u/M |rh22|/ν

2200 2250 2300 2350 2400 2450 2500 2550 2600 2650 2700 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

EOB (point-mass) EOB tidal LO EOB tidal 2PN α(2)

2

= 85/14 T4 tidal LO WENO (H)

lunedì 28 maggio 2012

slide-27
SLIDE 27

500 1000 1500 2000 2500 0.05 0.1 0.15 0.2 0.25

u/M Mω22

2200 2250 2300 2350 2400 2450 2500 2550 2600 2650 2700 0.05 0.1 0.15 0.2 0.25

EOB (point-mass) EOB tidal LO EOB tidal 2PN α(2)

2

= 85/14 T4 tidal LO WENO (H)

500 1000 1500 2000 2500 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

u/M |rh22|/ν

2200 2250 2300 2350 2400 2450 2500 2550 2600 2650 2700 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

EOB (point-mass) EOB tidal LO EOB tidal 2PN α(2)

2

= 85/14 T4 tidal LO WENO (H)

⇒ LO or NNLO models are Ok up to contact ! Not possible to probe amplification, but αeff2<40 EOB tidal 2PN better but within errorbars

lunedì 28 maggio 2012

slide-28
SLIDE 28

S.Bernuzzi - Tobemory, May 28th 2012

Summary

  • 9 orbits BNS waveforms converging up to Mω22 < 0.07-0.075 (~ before

contact), error estimates are necessary and difficult !

  • Several systematic uncertainties: more work required to obtain

“accurate” waveforms (more resolution, different numerical techniques/ specific methods for inspiral)

  • With “best NR waveforms”:
  • Tidal effects significant towards contact (LO is needed!)
  • (Strong) amplification previously observed likely due to numerical

inaccuracies, but still allowed 6 < αeff2 < 40

  • Tidal models (EOB, T4) compatible up to contact (EOB better but

within the errors). NOT possible to distinguish 1/2 PN (LO/NNLO).

  • “Validate” analysis of Damour et al 2012 on EOS detectability

lunedì 28 maggio 2012