The Astrophysics of Gravitational Wave Sources Conference Summary

The Astrophysics of Gravitational Wave Sources Conference Summary: Ground-Based Detectors (1 -104 Hz) Kimberly New, LANL

Detection & Data Analysis: LIGO & GEO’s science runs Brady & Mavalvala • high sensitivity, large bandwidth, hours of coincident operation • searches – NS/NS chirps, bursts, known pulsars, stochastic bkgd. • techniques used • science implications

Detection & Data Analysis: Detectors in 2012 Finn • interferometers - sensitivity improvements – <50 Hz: improve seismic isolation • active isolation • multiple levels of suspension – 50 -200 Hz: mitigate thermal noise • suspension system (increase mass, used fused silica ribbon) • test masses (sapphire) – >200 Hz: reduce shot noise • increase laser power

Detection & Data Analysis: Detectors in 2012 Finn • resonant acoustic detectors – current sensitivity 10 -22 near 900 Hz (1 Hz bandwidth) – future • spheres, spheres within spheres • 100 Hz bandwidth near 1 KHz (with improved amplifiers) • gravitational wave astronomy – NS/NS coalescence to 400 Mpc – stellar BH/BH coalescence to z=0. 5 – pulsars ( ~ 10 -6 at 102 Hz)

Sources: Binaries Schutz, Centrella, Bulik, Heyl • BH/BH Coalescence (Centrella, Schutz) – – – – LIGO: stellar mass BH/BH binary final coalescence signal will contain astrophysically rich info: spins, strong field GR simulations of vacuum field eqns. scale w/ mass & spin evolve single BHs for 103 M ! binary BHs for 102 M (~orbital period) ! “Discovery Channel” simulation of merger (AEI) simulation of ringdown w/Lazarus perturbative code remaining numerical issues • stability (formalism, gauge choices, boundary conditions) • physical initial data • waveform extraction

Sources: Binaries Schutz, Centrella, Bulik, Heyl • chirp mass measurement could constrain binary evolution – parameter studies with population synthesis code (Bulik, Kalogera) – compact binary mass distribution: “fingerprints” – most evolution input parameters could be constrained with ~100 chirp mass observations • effects of r-mode instability on LMXBs (Heyl) – r-mode saturation – detection with LIGO? – EM signatures?

Sources: Intermediate-Mass Black Holes Mushotzky, van der Marel, Miller • observations suggest existence • formation channels: Pop III stars, cluster interactions • GWs – 10 -50 M , 10 s of LIGO II detections per year – > 100 M , frequency generally too low for LIGO (ringdown? )

Sources: Collapse Mezzacappa, Fryer • Core collapse supernovae – precision modeling of macro & micro physics is the goal – steps along the way indicate sensitivities (e. g. , neutrino transport, EOS, general relativity) – multi-D simulations with multi-frequency neutrino transport don’t yet yield explosions – GW characteristics sensitive to EOS/GR (not as sensitive to neutrino transport) – new 3 D SPH simulations of 15 M stars (Fryer & Warren) • GWs from bar instability detectable with LIGO II (100 cycles, 10 Mpc) • GWs from proto-NS convection detectable for Galactic SNe

Sources: Collapse Mezzacappa, Fryer • Pop III, first generation stars – massive (no metallicity driven winds) – SPH collapse simulation of 300 M rotating star (Fryer et al. ) • core rotating fast enough to develop dynamical bar instability • high redshift puts GWs from bars & BH ringing out of LIGO II range • fragmentation could be detectable with LIGO II (but does it occur? )

Sources: GRBs Mészáros, Norris • GWs from GRBs – long GRBs, strong association with collapse – short GRBs, binary merger? – GW and GRB emission polarized; observations with third generation detector could measure 1% polarization in a year (Kobayashi & Mészáros) • Nearby GRB/GW sources? (Norris) – class of nearby GRBs associated with Type Ic SNe? (long pulses, long lags, soft spectra, subluminous) – ex. : GRB 980425/ SN 1998 bw (38 Mpc); GRB 030329 (680 Mpc) – concentrated near Supergalactic Plane; observed asymmetries – temporal separation of GRB and SNe? separate GW signatures? – could see 4 per year with LIGO II (50 Mpc, 100 cycle bar)

Sources: unexpected – dark matter? • 30% of universe • couple to gravitational radiation • GW observations could determine if distribution is smooth

In Summary • What information can we provide along the way to selfconsistent simulations? (timing info, etc. ) • Observation Informs - Finn • Is study of GWs from marginal sources worthwhile? – have “guaranteed” sources, “luxury” of studying others – often other drivers for study (SNe, GRBs, etc) – today’s marginal source can become tomorrow’s observed source (galactic supernova)