Detecting a Galactic Supernova with H2 or GEO P.H. for the LSC-Virgo Burst Group Expected rate for SN (type 2) events: ~ 2 / century in the Milky Way Expected signals: - GW - neutrinos - photons Chronology: - collapse - bounce - GW emission (~ coincident with the bounce) - neutrino flash ( slightly delayed wrt GW) - thermal neutrinos - photons (delayed by hours) => useless Scenario: detection of neutrinos (SK, SNO …) from a Galactic SN and search for a coincident event in a GW detector. => How neutrinos can improve a SN event detection

Timing GW-bounce Average over the Zwerger&Mueller catalogue (78 waveforms): Dt GW-bounce ~ 0.1 +/- 0.4 ms Accuracy penalized by “type 3” waveforms (type 3 disappeared in recent work) Type 3 Zwerger and Mueller, 1997. Dimmelmeir, Ott et al., 2007.

Neutrino emission Neutronization flash (electron neutrinos) - release ~ a few 1044 J - duration sflash ~ 2.3+/-0.3 ms. - => luminosity ~1048 W Thermal emission (n`n pairs) - 99% energy, up to 5x1045 J / neutrino type - En ~10-20 MeV

(if GW peak detected par Gaussian templates exp(-t 2 / 2t 2) ) Delay GW-neutrinos (I) Statistical errors on arrival times Neutrinos: For a SN @ 10 kpc, Ne ~10 (SK or SNO) - Gravitational waves: (if GW peak detected par Gaussian templates exp(-t 2 / 2t 2) ) Assuming Ne =10, t = 2ms and SNR=5:

Delay GW-neutrinos (II) Systematic error on arrival time: Supernova models : Dt GW-bounce ~ 0.1 +/- 0.4 ms (Z&M) Dt nflash-bounce ~ 3.5 +/- 0.5 ms (Z&M and DFM) Get rid of the bounce time reference -> relative delay between GW and n flash: Dt nflash-GW ~ 3.5 +/- 0.5 ms This is the delay at the source, still correct on the Earth if ne is massless. If ne is massive -> additional delay due to propagation: Current upper limits on ne mass:

Strategy Neutrino flash detected by n-detector on Earth Expected delay between GW and n (GW arrive first): Syst. Stat. (Very conservative) Look for GW only into a small window around the neutrino event. Allow for decreasing search threshold inside such a small window Choice of the coincidence window ? Dt ~10 ms aggressive choice ! Dt ~50 ms safer choice ! Let’s go with Dt ~50 ms. Set the False Alarm probability to ~1% inside the time window. This sets the FAR to be ~0.2 Hz. Tune the pipeline threshold accordingly

H2 detection range HW injection of SN signal in LIGO: Waveform: ZM A3B3G1 Pipeline: KW FAR: 0.2 Hz H2 90% efficiency for hrss ~7x10-22 Hz-1/2. This converts to a distance d90 ~ 7 kpc

Extrapolation to GEO Ratio H2/GEO sensitivities ~ 8 @ 300Hz. ZM a3b3g1 spectrum h(f) (Hz-1) Peak @ ~300 Hz freq. (Hz) Ratio H2/GEO sensitivities ~ 8 @ 300Hz. Assuming same glitchiness for GEO as for H2, d90 ~ 0.9 kpc Optimistic range since glitchiness of H2 seems better than GEO’s Slightly improved if shift towards higher frequencies …

Conclusion Scenario of SN search triggered by a neutrino flash. Coincidence with neutrino allows for a low threshold in a small coincidence window (few 10s of ms) H2 detection range ~ 7 kpc for ZM signal a3b3g1. GEO detection range < 1 kpc for the same signal. (Virgo [may 2007] similar to H2 and L1/H1 should cover the entire Galaxy). Issues: + beam pattern effect More efficient pipeline ? More recent waveform (Dimmelmeir, Ott et al., higher frequencies …) ?