Key Results from Dynamical Spacetime GRMHD Simulations. Zachariah Etienne

Transcription

1 Key Results from Dynamical Spacetime GRMHD Simulations Zachariah Etienne

2 Outline Lecture 1: The mathematical underpinnings of GRMHD, astrophysical importance Lecture 2: Solving GRMHD equations numerically Lecture 3: Key results from large-scale GRMHD simulations

3 Outline Lecture 1: The mathematical underpinnings of GRMHD, astrophysical importance Lecture 2: Solving GRMHD equations numerically Lecture 3: Key results from large-scale GRMHD simulations

4 Outline Lecture 3: Key results from large-scale GRMHD simulations

5 Lecture 3: Key results from large-scale GRMHD simulations

6 BH NS Short GRB Detectable GWs BH1 BH2 BBH AGN

7 Key Results from Dynamical Spacetime GRMHD Simulations: Compact Binaries BH1 BH2 (original image: Lovelace et al., CQG 29, (2012))

8 Key Results from Dynamical Spacetime GRMHD Simulations: Compact Binaries NS1 NS2 (original image: Lovelace et al., CQG 29, (2012))

9 Key Results from Dynamical Spacetime GRMHD Simulations: Compact Binaries BH NS (original image: Lovelace et al., CQG 29, (2012))

10 Key Results from Dynamical Spacetime GRMHD Simulations: Compact Binaries BH1 BH2 (original image: Lovelace et al., CQG 29, (2012))

11 Key Results from Dynamical Spacetime GRMHD Simulations: Compact Binaries GWs carry away orbital energy and angular momentum from CB, leading to inspiral & merger Early inspiral, small velocities use pert solution to GR GWs BH1 BH2 Late inspiral & merger: pert solns break down. NEED NR (original image: Lovelace et al., CQG 29, (2012))

12 Key Results from Dynamical Spacetime GRMHD Simulations: Compact Binary Merger Simulations Most likely sources for first incident GW detection BH BH BH NS NS NS 4 km LIGO: Hanford (WA) LIGO: Livingston (LA)

13 Key Results from Dynamical Spacetime GRMHD Simulations: Compact Binary Merger Simulations Most likely sources for first incident GW detection BH BH BH NS NS NS 4 km LIGO: Hanford (WA) LIGO: Livingston (LA)

14 Key Results from Dynamical Spacetime GRMHD Simulations Compact Binary Mergers Black hole + Black hole (BBH)

15 Key Results from Dynamical Spacetime GRMHD Simulations Compact Binary Mergers Black hole + Black hole (BBH) Largest separation BBH: 100M Szilagyi, Blackman, Buonanno, Tarrachni, Pfeiffer, Scheel, Chu, Kidder, Pan: arxiv: First NR sim to go through full LIGO waveband: 350 GW cycles! Lousto & Zlochower: PRD 88, (2013)

16 Key Results from Dynamical Spacetime GRMHD Simulations Compact Binary Mergers Black hole + Black hole (BBH) Very computationally expensive, even with state-of-the-art codes. Used to enhance fast GW approximants Largest separation BBH: 100M Szilagyi, Blackman, Buonanno, Tarrachni, Pfeiffer, Scheel, Chu, Kidder, Pan: arxiv: First NR sim to go through full LIGO waveband: 350 GW cycles! Lousto & Zlochower: PRD 88, (2013)

17 Review: Supermassive black holes Supermassive black holes Galaxy mergers common, cores merge Exist at core of every galaxy Binary black holes must exist, but never definitively observed! Active galactic nuclei (AGNs) Accretion disk forms around supermassive black hole, get jets Some AGNs may be from binary black holes!

18 Collaborators: Brian Farris Roman Gold Yuk Tung Liu Vasileios Paschalidis Stu Shapiro BH2 AGN cc a (original image: Lovelace et al., CQG 29, (2012))? retion dis APEX, Chandra, MPG/ESO k BH1

19 .. BH's

20

21

22 APEX, Chandra, MPG/ESO

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24 Gravitational Waves Most likely sources for first incident GW detection Black hole + Black hole (BBH) Black hole + Neutron star (BHNS) Neutron star + Neutron star (BNS)

25 Suppose... LIGO detects chirp mass w/in BHNS range Can we know for sure: Is it BHNS or BBH? Lackey et al (Kyoto/Princeton/UWM collab) PRD (2014)

26 Tidal Love number (TLN) (TLN): distinguishes point mass vs non-point mass Constrained by ~10-100% for Adv LIGO (1-sigma) NS Disruption: at the right-edge of the AdvLIGO noise curve Add wf prior to merger TLN no better Prior to merger get TLN accuracy 3x better BUT correlations with other params TLN 3x worse Lackey et al (Kyoto/Princeton/UWM collab) PRD (2014)

27 Tidal Love number (TLN) Adv LIGO: Constrained by ~10-100% (1-sigma) ET: Constrained by ~1-10% (1-sigma) Lackey et al (Kyoto/Princeton/UWM collab) PRD (2014)

28 Suppose... LIGO detects chirp mass w/in BHNS range Can we know for sure: Is it BHNS or BBH? May need EM counterpart during inspiral!

29 Short GRB Scenario NS BH BH BH + disk

30 Short GRB Scenario NS BH BH BH + disk

31 Short GRB Scenario NS BH Short GRB

32 BHNS Mergers: When will NS tidally disrupt & generate GWs distinguishable from BBH? Parameters important for NS disruption Newton: Expect tidal orbital separation grav NS surf. Expect: Stronger inequality BBH, BHNS more distinguishable Also: Test particle around Kerr BH spin increases BH tidal force : when: decreases as aligned Expect more disruption & remnant disk outside BH as aligned spin increases

33 Black Hole-Neutron Star Mergers: Remnant Disk Masses BH NS Figure based on data from UIUC, Kyoto, and SXS BHNS NR simulations Foucart, PRD 86, (2012)

34 Black Hole-Neutron Star Mergers: Remnant Disk Masses BH NS lik HBB re Mo W eg s Figure based on data from UIUC, Kyoto, and SXS BHNS NR simulations Foucart, PRD 86, (2012)

35 Black Hole-Neutron Star Mergers: Remnant Disk Masses BH NS Take-Home Message: For most likely systems (BH=10Msun, or ~7:1 mass ratio), only cases with a highly spinning, aligned BH yield significant disk Lower spins BHNS GW's more like BBH! Most of parameter space may be indistinguishable from BBH Foucart, PRD 86, (2012)

36 Black Hole-Neutron Star Mergers: Remnant Disk Masses H B B t + S os e N l H m b B a s h W G guis n i t s i d BH NS Figure based on data from UIUC, Kyoto, and SXS BHNS NR simulations Foucart, PRD 86, (2012)

37 The Unipolar Inductor: Qualitative analysis Setting: The magnetosphere of a magnetized body corotates with the body sweeping the companion Dong Lai, 2012 The companion will cut B-field lines an EMF will be induced. Currents will be driven and dissipated. The energy dissipation rate is

38 Application: BHNS binaries Paschalidis, Etienne, Shapiro PRD (2013) McWilliams and Levin (2011) postulated that UI applies to BHNS binaries. The NS is the magnetic object, the BH is the conducting body. In the membrane paradigm of a BH, the BH can be considered as a sphere of radius RH=2GM/c2 and resistance R=4π/c. The energy dissipation rate becomes Our NR GRFFE simulation results agree!

39 Poynting flux angular distribution a/m = 0.75 Beacon lighthouse effect Characteristic quasiperiodic EM signature prior to merger? Paschalidis, Etienne, Shapiro PRD (2013)

40 orbital J PB/PGas BH a/m= x 10-3 Etienne et al (Illinois) PRD 86, (2012) * BH NS

41 Etienne et al (Illinois) PRD 86, (2012)

42 BHNS MERGER RI J. Hawley, Etienne et al (Illinois) PRD 86, (2012)

43 BHNS MERGER RI Exponentially amplified poloidal fields MHD turbulence = eff. viscosity, drives accretion Jet fo rmati on GRB? J. Hawley, Etienne et al (Illinois) PRD 86, (2012)

44 RI Exponentially amplified poloidal fields MHD turbulence = eff. viscosity, drives accretion Jet fo rmati on GRB?

45 RI Exponentially amplified poloidal fields MHD turbulence = eff. viscosity, drives accretion Jet fo rmati on GRB?

46 RI Exponentially amplified poloidal fields MHD turbulence = eff. viscosity, drives accretion Jet fo rmati on GRB?

47 RI Exponentially amplified poloidal fields MHD turbulence = eff. viscosity, drives accretion Jet fo rmati on GRB?

48 RI Exponentially amplified poloidal fields MHD turbulence = eff. viscosity, drives accretion λmri Jet fo rmati on GRB?

49 RI Exponentially amplified poloidal fields MHD turbulence = eff. viscosity, drives accretion λmri Jet fo rmati on GRB?

50 Turbulence Hot funnel edge outflows

51 Key Results from Dynamical Spacetime GRMHD Simulations Compact Binary Mergers Black hole + Neutron star (BHNS) Paschalidis, Ruiz, Shapiro arxiv: BHNS: apparent sgrb engine observed from self-consistent simulations However: most of parameter space: NS plunges no disk no sgrb BNS: Interesting magnetic structures develop, possible sgrb precursor

52 Numerical Relativity's Contributions to Astrophysics: Gravitational Waves Most likely sources for first incident GW detection Black hole + Black hole (BBH) Black hole + Neutron star (BHNS) Neutron star + Neutron star (BNS) NR provides first self-consistent BNS GWs, including tidal disruption, merger, & BH formation BNS merger: Much richer GWs possible than BHNS 3 possible remnants Hot, but stable NS HMNS: Quasi-stable, will collapse to BH Prompt collapse to BH GWs may encode information about NS EOS, bar modes, magnetic fields, remnant cooling efficiency

53 Key Results from Dynamical Spacetime GRMHD Simulations Binary Neutron Stars Bernuzzi, Dietrich, Tichy, Bruegmann PRD (2014) Giacomazzo & Perna: ApJ 771 L26 (2013) Giacomazzo, Rezzolla, & Baiotti: PRD (2011)

54 Key Results from Dynamical Spacetime GRMHD Simulations Binary Neutron Stars Bernuzzi, Dietrich, Tichy, Bruegmann PRD (2014) Giacomazzo & Perna: ApJ 771 L26 (2013) Giacomazzo, Rezzolla, & Baiotti: PRD (2011) Extremely violent inspiral/merger: NS-disrupting torques, accel to rel. velocities extreme heating, enormous influence on B-fields, rel. jets? BNS merger Short Gamma-ray burst?

55 Key Results from Dynamical Spacetime GRMHD Simulations BNS merger Short Gamma-ray burst? Highest resolution simulation of magnetized BNS merger: No evidence of relativistic outflows or B-field collimation (coherent poloidal field). Kiuchi, Kyutoku, Sekiguchi, Shibata, & Wada, PRD 90, (2014)

56 Key Results from Dynamical Spacetime GRMHD Simulations Short Gamma-Ray Bursts Bernuzzi, Dietrich, Tichy, Bruegmann PRD (2014) Giacomazzo & Perna: ApJ 771 L26 (2013) Foucart, Deaton, Duez, Kidder, MacDonald, Ott, Pfeiffer, Scheel, Szilagyi, Teukolsky: PRD (2013) Black hole + Neutron star (BHNS) Radice, Rezzolla, Galeazzi: CQG (2014) Neutron star + Neutron star (BNS) Extremely violent inspiral/merger: NS-disrupting torques, accel to rel. velocities extreme heating, enormous influence on B-fields, rel. jets

57 Key Results from Dynamical Spacetime GRMHD Simulations: Compact Binary Merger Simulations Most likely sources for first incident GW detection BH BH BH NS NS NS 4 km LIGO: Hanford (WA) LIGO: Livingston (LA)