=== Gabriela Gonzalez - status of ground-based interferometers === - international network (already exists, joint data analyzed) - TAMA300: new seismic isolation, dL = 4e-19 m/Hz-1/2, strain = 1e-21 - CLIO: 100m in Kamioka mine; reached the thermal-noise limit; lower displ. seismic noise than other detectors; will start cooling - LCGT: future 3km, underground, cryogenic; dates similar to AdvLIGO - GEO600: spring 2009--DC readout, injection of squeezed vacuum; 2010: increase laser power - AIGO: proposal, project office - Virgo: Virgo+ enhancements for VSR2; advanced Virgo under review this year - LIGO: enhanced LIGO has 35W power, better magnets, in-vacuum active seismic isolation, DC readout, 2x better than S5; advanced LIGO (comm. 2014) adds signal recycling, increased laser power, heavier mirrors with low-noise coatings, 10x amplitude sensitivity leads to x1000 rate === Curt Cutler - status of space-based detectors === - LISA orbits, laser links (w/TDI) - LISA sources - Galactic binaries: table from Nelemans astro-ph/0310800; WD-WD (noninteracting and AM CVn) - black holes: strong - EMRIs: diagram of loss cone from Freitag and Benz 2002 - cosmic strings: cusp once per oscillation cycle; Siemens' diagram with visibility regions for background and bursts - LISA pathfinder - squeeze one arm to one spacecraft - pathfinder orbits to L1 - GRS, same technology as LISA, noise within x10 of LISA req., down to 1e-3 Hz - uN thrusters - only LISA items not tested on LPF: anything s/c-to-s/c - LISA politics - BEPAC to decide on 2009 funding wedge; gave LISA highest scientific rating; 2018 launch feasible; BUT JDEM to go first, LISA prepare for 2011 funding wedge, after LPF - NASA response: abolish BEPAC, no 2009 wedge, Con-X -> IXO, GSFC gets JDEM, astro2010 reviews JDEM - astro2010: because nothing done except JWST (4.5x cost) from 2000 report, big pile-up - ESA Cosmic Vision downselect for L-class mission, launch < 2020 - so for LISA to fly: get high astro2010 ranking, LPF success, win Cosmic Vision downselect - MLDCs - LISAPE taskforce - DECIGO: 0.1 to 10 Hz, low confusion noise, access to cosmological stochastic background after removing 1e5 BNS - BBO: laser 300xLISA, mirror 12xLISA, armlength 0.01xLISA, accel noise 0.01xLISA, need BNS subtraction (Cutler and Harms 2006 method, Harms et al. 2008 simulations, also Tokuda and Kanda) === Rick Jenet - pulsar timing for GW detection in the nHz band === - Galactic-scale observatory - groups: PPTA (Parkes), NANOGrav (Arecibo, Green Bank), EPTA (European) - Large European Array for Pulsars will synthesize Arecibo-size dish - GW detection with pulsar timing: measure times of arrival (TOAs) of individual pulses, subtract expected TOAs, amplitude ~ h/f (integrated instantaneous Doppler shift), look for correlations between signals of different pulsars === Soumya Mohanty - multidetector glitch classification === - glitch database from KleineWelle database, many aux channels - multidimensional hierarchical classification - based on distances between events - identified classes used for glitch identification - what's the trigger content of each class? what connection to possible sources? - use detector-wide channel scan - significance volume = number of triggers x KleineWell significance - run pipeline in real time - standalone mode for follow-up work - autotrack: detect new glitches that may appear === Leroy - noise events in VSR1 === - MBTA for CBC, Q pipeline for Burst - CBC and Burst study DQ flags to: - define category (1: obvious problem; 2: environmental disturbance with origin, coupling understood; 3: coupling not understood; 4: advisory) - determine window size - compute dead time, use percentage, efficiency (for given SNR) - check dead time - in VSR1, mostly cat2, dead time 4.3% === Johnson - it's mostly signal analysis === - We're a virtual science (no observations): need higher standards for accessibility, transparency, reliability in all aspects, including data validity, data analysis, data interpretation - need guide to GW data analysis for beginners: grad students, astronomers/particle physicists, ourselves - use "signal processing for beginners"? This book is a work in progress - what's specific to GWs? We're not detecting particles, but waves, or better strain wave meters - vector notation good for everything: linear and quadratic combinations === S. Frasca - robust estimation of parameters of disturbed nonstationary Gaussian process === - model: stationary Gaussian process + big random pulses, any amplitude distribution, much higher variance - variance estimator needs to be modified in the presence of disturbances... - instead make a histogram of amplitudes, use matched filter with theoretical distributions - can do for Gaussian and exponential processes === D. Bessis - analytic approach to the concept of noise === - z transform: generalization of FFT to complex frequencies - what's the z transform of the noise? whatever its statistical properties, it's a function with *natural boundary* on the unit cycle; the roots of unity are attractors - new computational method to derive the transform (Beckelman?) - Steinhaus theorem: noise poles are always Lorentz-distributed around unit radius === B. Owen - stack-a-flare SGR burst search method === - SGR - 100 ms bursts, 1e-42 erg/s peak - rare giant flares, 1e47 erg/s; also burst storms - share properties with earthquakes - magnetar model - in NS with B 1e15 G, field/crust dynamic leads to cracks - PRL 101, 211102 (2008) - S5 search sensitive to f-modes - 191 SGR events, including giant flare and storm - gamma = E_GW / E_EM < 1e4 (not wildly unreasonable from models) - stacking bursts - assume consistent GW emission and combine presumed events to improve detection efficiency and upper limits - different ways to stack bursts === P. Shawhan - S5/VSR1 burst searches === - short signals in the sensitive frequency band - many types of data - LF-search pipelines - BlockNormal + CorrPower (excess power and cross-correlation) - QPipeline (whitening, matched filter for sine gaussians; combined H1 and H2 into H+ and H-) - Coherent Waveburst (wavelets, network SNR) - HF-search pipelines - Omega, Coherent WaveBurst - EGC (Gaussian-envelope sinusoids) - how to achieve false alarm rate? How to cluster? - standard pipeline elements - data-quality cuts, glitch vetos - full dataset (detection) vs. clean dataset (upper limits) - background using time shifts - efficiencies from injections (sine-Gaussian, band-limited white noise) - S5: combine results of all pipelines into one upper limit - handle combinations properly - detection statistic is weighted sum, different for different injections === J. Rollins - online searches for unmodeled bursts in S6/VSR2 === - purpose - produce event candidates for follow-up at other observatories - use event alerts more quickly - assist detector characterization - science: gravitational waves are coincident with other signals - observatories - EM: wide-field optical (SkyMapper, ROTSE, TAROT, Quest), radio, X-ray - neutrino: Super-L, LVC, IceCube, ... - target latencies - 30 minutes at beginning of run, 10 by end - tune false alarm rate depending on external collaborator ingestion capability - quality events - three sites enable signal, polarization, and sky-location signal reconstruction - use Omega single/multi-detector pipeline - trigger spectrograms === A. Searle - reconstructing the position of unmodeled burst sources === - S5/VSR2 can triangulate sources, provide event alerts - back of the envelope: 300 Hz -> LIGO-Virgo baseline 30 ms = 10 cycles -> projection onto 90 deg -> 9 deg -> super-resolution 9 deg / sqrt(SNR 10) = 3 deg - good enough for wide-field telescopes - sky localization challenge: median angle error is about 3 linear degrees