1. LIGO - Fermi Sub-Threshold Search for the 1 st Advanced LIGO Science Run Jordan Camp NASA Goddard Space Flight Center Moriond Gravitation Meeting March 25, 2015 Search Team Lindy Blackburn (CfA) Nelson Christensen (Carleton College) Valerie Connaughton, Michael Briggs, Binbin Zhang (UAH) Peter Shawhan (U Md) Leo Singer (Goddard NPP) John Veitch (U Birmingham)

2. Advanced LIGO is now operating Washington Louisiana Gravitational Wave causes differential arm displacement  photodetector signal

3. Advanced LIGO Sensitivity Goal Factor 10 lower noise at high frequency Higher power laser Factor 10 lower noise at low frequency Active seismic isolation Factor 6 lower cutoff frequency Multiple suspensions in series Advanced LIGO Initial LIGO BNS range 20 Mpc Advanced LIGO BNS range 200 Mpc (Washington 28 Mpc, Louisiana 68 Mpc)

4. Recent LIGO Noise Spectrum Initial LIGO, 20 Mpc Advanced LIGO, 59 Mpc Design Sensitivity, 138 Mpc (Laser power = 25 W) O1 run this summer

5. Short Gamma-Ray Burst sGRB Fermi sGRB is most likely due to merging of Neutron Stars Inspiral of NS – NS produces GW, merger produces burst of Gamma-rays Excellent candidate for coincident detection of GW and Gamma-ray Overlap of GW/Gamma-ray in time and location  subthreshold detection > 100 sGRBs observed by Fermi Gamma-Ray Burst Monitor (GBM) 12 Na I detectors in varying orientations, 5 degree position resolution GW is roughly isotropic, but Gamma-ray is beamed (10 degree opening) Need sGRB within LIGO horizon (400 Mpc), and beamed at earth

6. LIGO – GBM Coincident Search GBM coincidence in time and space will help verify the GW event Followup of GBM with eg Palomar Transient Facility  localization host galaxy, redshift, accurate BNS parameter extraction Relative timing of Gamma-ray and GW  mass of Graviton Energetics, beaming, and nature of sGRB Information on NS Equation of State ? NS-NS merger: Short Gamma-Ray Burst (sGRB) LIGO Fermi GBM GWs Gamma-rays 4  FoV 2  FoV 100 deg 2 25 deg 2

7. Coherent Analysis of GBM Detectors (L. Blackburn and UAH) signal noise data Instrument response source Evaluate  by marginalizing over source amplitude, position r i provided by GBM detector model (Connaughton, UAH) Factor 2 gain in SNR

8. 8 Test of Initial LIGO – GBM coincident analysis L. Blackburn, ApJ S 217 (2015) ASM GBM LIGO BNS trigger LIGO sky localization

9. 9 sGRB Precursors and NS EOS E. Troja et al, Ap J 723 (2010)

10. NS Crust Resonant Shattering Process Tsang et al, PRL 108 (2012) 10 Mode Energy ~ 10 47 erg  Fracture Seismic Energy ~ 10 46 erg  Shattering Luminosity ~ 10 46-47 erg 0.1 sec (can see 10 47 erg at ~ 150 Mpc) Isotropic (!) Available Tidal Energy ~ 10 50 erg

11. 11 Investigating NS Crust Equation of State f res (from GW) at time of Precursor  NS EoS

12. Optimistic O1 LIGO and sGRB Rates aLIGO BNS Detections sGRB Detections Typical jet angle ~ 10 degree  beaming factor ~ 100 Thus 3 LIGO BNS detections  ~ 0.03 coincident sGRB detection  ~ 0.3 (subthreshold/GW on jet axis) Realistic rates likely to be factor 10 lower…  look to O2, O3

13. O1 LIGO – GBM Search O1 run around fall 2015 – 3 months – Hanford and Livingston detector range > 60 Mpc Pipeline development – Further tests of GBM coherent analysis – Use GBM continuous data from every downlink (CTTE) – LIGO sky localization: low-latency to enable real-time alerts Run pipeline – Analyze results and get ready for O2 run at > 100 Mpc – Continue development of GBM coherent analysis (UAH)