1 Discussion of bursts implications for GRB We consider an inspiral/merger scenario... Possible bursts (CC with 25ms or 100ms integration) applications: 1.Near the merger – short, not well-modeled waveforms  ~ unique to burst-type analysis 2.Detection of short segments of the inspiral  “backup” to standard inspiral analysis

2 BH-NS merger Model: A BH tidally disrupts a NS before reaching horizon, a matter disk of few x 0.1M  can form  GRB engine  Prefers a BH with mass less than ~5-10 M  Shibata and Uryu, 2006 Numerical relativity 0.5 ms  M/M 

3 BH-NS merger (contd) Numerical relativity: f merge = 2/  ISCO = 8kHz / (M/M  ) Waveforms depend on EOS; claimed GR unknown ~10% 1 ms  M/M  Shibata and Uryu ISCO – ~inspiral/coalescence transition Issues: f merge high  D  1/ f  Instrument noise 25 ms (100 ms) will include last part of inspiral at lower freq.  Which frequency to use?

4 BH-NS merger (contd) We would like to form a robust limit which includes the merger: Waveforms near merger are not well known But assume ISCO frequency is robust Example: M NS+BH = 10 M   f merge = 800 Hz  energy-weighted frequency over 100 ms is 500 Hz (a guess!) Isabel L.

5 BH-NS Inspiral The CC algorithm will pick up 25 ms or 100 ms bits of the inspiral as its frequency passes through the best detector sensitivity. (Note that there is no clustering of “loud” CC bins.) Use Patrick Sutton’s MDC inspiral waveforms. Find distance at which 90% of injections are above off-source background   1 Mpc (prelim.) Isabel L

6 more discussion... GRB beaming: Missed MDC inspirals mostly due to unfavorable orientation of inspiral (  /2). Modest beaming would presumably improve the limit. (Need to check the numbers.) How serious are NS-NS mergers as GRB progenitors? Relevant BH mass range for NS/BH ? How to choose “average” freq of merger in CC bin ? What is current max freq cutoff in template-based inspiral analysis ?