BBH simulations and their applications: an update

BBH simulations and their applications: an update

BBH simulations and their
applications: an update
Harald Pfeiffer
CITA
CIfAR Gravity & Cosmology AGM
Feb 19-21, 2010, Lake Louise, Canada
in collaboration with A. Mroue (CITA)
and groups at Caltech, Cornell, U. Maryland:
G. Lovelace, L. Kidder, M. Scheel, B. Szilagyi, L. Lindblom,
A. Taracchini, A. Buonanno
Sunday, February 21, 2010
LIGO
Initial LIGO
-2007
enh.LIGO+Virgo 09-10
Advanced LIGO 2014(Ad-LIGO)
Sunday, February 21, 2010
d/Mpc events/yr
BBH
~800
2-4000
BH-NS
~500
0.4-400
NS-NS
~300
0.2-300
LIGO
BBH/BH-NS Science goals
• First observation of BBH
• First observation of BH-NS
• census of compact object
binaries (mass, spin, DL)
• Info about formation
channels (SN, GC)
• BH-NS:
• Eqn. of state
• Gamma-ray-burst?
• Test GR
Sunday, February 21, 2010
Initial LIGO
-2007
enh.LIGO+Virgo 09-10
Advanced LIGO 2014(Ad-LIGO)
d/Mpc events/yr
BBH
~800
2-4000
BH-NS
~500
0.4-400
NS-NS
~300
0.2-300
LIGO data-analysis: Matched filtering
✦
< s, h >
SNR =
< h, h >1/2
�
h̃1 h̃∗2
< h1 , h2 >= 4Re
df
Sh
✦ Must know expected signals to...
find them
characterize them
set upper limits if no detection
•
•
•
✦ High phase-accuracy crucial!
✦ Requires simulations of late
inspiral and merger
Sunday, February 21, 2010
(Courtesy D. Brown)
Caltech-Cornell-CITA: Spectral Einstein Code
✦ expand in basis-functions
N
�
u(x, t) ≈
ũk (t)Φk (x)
compare to Finite differences
k=1
Lehner, Pretorius
AEI, Georgia Tech,
Goddard, Rochester
Key advantage: smooth solutions
exponential convergence
... but more difficult than finite differences
Sunday, February 21, 2010
Numerics 2: Domain-decomposition
Sunday, February 21, 2010
Numerics 2: Domain-decomposition
✦ Many sub-domains, each with own basis-functions
• Spheres, blocks, cylinders
Sunday, February 21, 2010
Numerics 2: Domain-decomposition
✦ Many sub-domains, each with own basis-functions
• Spheres, blocks, cylinders
Sunday, February 21, 2010
Numerics 2: Domain-decomposition
✦ Many sub-domains, each with own basis-functions
• Spheres, blocks, cylinders
Sunday, February 21, 2010
Numerics 2: Domain-decomposition
✦ Many sub-domains, each with own basis-functions
• Spheres, blocks, cylinders
Sunday, February 21, 2010
Numerics 2: Domain-decomposition
✦ Many sub-domains, each with own basis-functions
• Spheres, blocks, cylinders
✦ Advantages:
• Excision of BH singularities
• Adaptive Resolution
• Parallelization
Sunday, February 21, 2010
Numerics 2: Domain-decomposition
✦ Many sub-domains, each with own basis-functions
• Spheres, blocks, cylinders
✦ Advantages:
• Excision of BH singularities
• Adaptive Resolution
• Parallelization
Versatile, accurate code for elliptic and hyperbolic PDEs
Sunday, February 21, 2010
Spectral methods: If they work, they do work.
✦ Compare 5 BBH codes during last six orbits
Hannam, et al, 2009
Sunday, February 21, 2010
Progress in numerics
✦ Precessing binaries
Courtesy Geoffrey Lovelace (Cornell)
Sunday, February 21, 2010
Robust Mergers!
M1/M2=2, S=0
Szilagyi, Lindblom, Scheel, arXiv:0909.3557:
Improved gauge conditions avoid
coordinate singularities
M1=M2, S=0
M1=M2, S=0.45
Scheel et al, 2008
Sunday, February 21, 2010
More Mergers
M1=M2, S=-0.45
Sunday, February 21, 2010
M2=2M1, S1=0.4, S2=0.2 (cf. Movie)
Eccentricity in BBH inspiral
✦ Non-precessing binaries
Sunday, February 21, 2010
Eccentricity control
✦ e radiated away during inspiral
�
r⊙
rs
�−17/12
✦ Compare ṙ(t) with Newtonian orbit, update
Sunday, February 21, 2010
∼ 10
−7
Ω0 , ṙ0
Eccentricity: Precessing binaries
✦
ṙ(t) contaminated by periodicity P/2
Sunday, February 21, 2010
Eccentricity control for precessing BBH
✦ Analyze dOmega/dt
• Works for PN, full BBH simulations underway
Sunday, February 21, 2010
Applications of numerical waveforms
✦ Numerical Injection Analysis -- NINJA
✦ Take NR waveforms
✦ Inject into LIGO/Virgo noise
✦ Run data-analysis pipelines
www.chocosho.com
Sunday, February 21, 2010
Ninja 1: Waveforms
CQG 26, 165008 (2009)
✦ Binary BH only, 10 numerical relativity groups
Sunday, February 21, 2010
Ninja 1: data-analysis pipelines
CQG 26, 165008 (2009)
Sunday, February 21, 2010
Ninja 1: Conclusions
✦ Very successful in getting communities to interact
✦ High visibility
CQG 26, 165008 (2009)
(top 10 download in 2009)
✦ Many lessons for Ninja 2
Sunday, February 21, 2010
Ninja 2: in progress
Ninja 1
Ninja 2
Pure numerical waveforms
fairly short: M>40Msun
Stitched NR-PN waveforms
probe astrophysically relevant
masses
Gaussian noise
results difficult to apply to “real”
non-Gaussian detectors
Actual LIGO/Virgo noise
Little coverage of parameter
space
Extend to systems with
aligned spins
Goal: realistic conclusions about detection efficiencies
Sunday, February 21, 2010