Stacked Search for Gravitational Waves from the 2006 SGR 1900+14 Storm

We present the results of a LIGO search for short-duration gravitational waves (GWs) associated with the 2006 March 29 SGR 1900+14 storm. A new search method is used, “stacking” the GW data around the times of individual soft-gamma bursts in the storm to enhance sensitivity for models in which multiple bursts are accompanied by GW emission. We assume that variation in the time difference between burst electromagnetic emission and potential burst GW emission is small relative to the GW signal duration, and we time-align GW excess power time-frequency tilings containing individual burst triggers to their corresponding electromagnetic emissions. We use two GW emission models in our search: a fluence-weighted model and a flat (unweighted) model for the most electromagnetically energetic bursts. We find no evidence of GWs associated with either model. Model-dependent GW strain, isotropic GW emission energy EGW, and γ ≡ EGW/EEM upper limits are estimated using a variety of assumed waveforms. The stacking method allows us to set the most stringent modeldependent limits on transient GW strain published to date. We find EGW upper limit estimates (at a nominal distance of 10 kpc) of between 2 × 10 erg and 6 × 10 erg depending on waveform type. These limits are an order of magnitude lower than upper limits published previously for this storm and overlap with the range of electromagnetic energies emitted in SGR giant flares. Subject headings: gravitational waves soft gamma repeaters 1 Albert-Einstein-Institut, Max-Planck-Institut für Gravitationsphysik, D-14476 Golm, Germany 2 Albert-Einstein-Institut, Max-Planck-Institut für Gravitationsphysik, D-30167 Hannover, Germany 3 Andrews University, Berrien Springs, MI 49104 USA 4 Australian National University, Canberra, 0200, Australia 5 California Institute of Technology, Pasadena, CA 91125, USA 6 Caltech-CaRT, Pasadena, CA 91125, USA 7 Cardiff University, Cardiff, CF24 3AA, United Kingdom 8 Carleton College, Northfield, MN 55057, USA 9 Charles Sturt University, Wagga Wagga, NSW 2678, Australia 10 Columbia University, New York, NY 10027, USA 11 Embry-Riddle Aeronautical University, Prescott, AZ 86301 USA 12 Eötvös University, ELTE 1053 Budapest, Hungary 13 Hobart and William Smith Colleges, Geneva, NY 14456, USA 14 Institute of Applied Physics, Nizhny Novgorod, 603950, Russia 15 Inter-University Centre for Astronomy and Astrophysics, Pune 411007, India 16 Leibniz Universität Hannover, D-30167 Hannover, Germany 17 LIGO California Institute of Technology, Pasadena, CA 91125, USA 18 LIGO Hanford Observatory, Richland, WA 99352, USA 19 LIGO Livingston Observatory, Livingston, LA 70754, USA 20 LIGO Massachusetts Institute of Technology, Cambridge, MA 02139, USA 21 Louisiana State University, Baton Rouge, LA 70803, USA 22 Louisiana Tech University, Ruston, LA 71272, USA 23 Loyola University, New Orleans, LA 70118, USA 24 Montana State University, Bozeman, MT 59717, USA 25 Moscow State University, Moscow, 119992, Russia 26 NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA 27 National Astronomical Observatory of Japan, Tokyo 181-8588, Japan 28 Northwestern University, Evanston, IL 60208, USA 29 Rochester Institute of Technology, Rochester, NY 14623, USA 30 Rutherford Appleton Laboratory, HSIC, Chilton, Didcot, Oxon OX11 0QX United Kingdom 31 San Jose State University, San Jose, CA 95192, USA 32 Sonoma State University, Rohnert Park, CA 94928, USA 33 Southeastern Louisiana University, Hammond, LA 70402, USA 34 Southern University and A&M College, Baton Rouge, LA 70813, USA 35 Stanford University, Stanford, CA 94305, USA