ligo-g030039-00-z external triggers circulation only within ligo i authorship list status of the...

LIGO-G030039-00-Z External TriggersCirculation only within LIGO I authorship list

Status of the Triggered Burst Search

(highlights from LIGO DCC# T030050-00-Z,“Triggered search analysis of S1 data associated

with X-ray Flash XRF020903”)

R. Rahkola, R. Frey (U. Oregon)

Sz. Márka (CIT)

S. Mohanty, S. Mukherjee (AEI)

LSC Meeting, LLO, March 17, 2003

LSC Meeting, March 17-20, 2003 2LIGO-G030039-00-Z External TriggersCirculation only within LIGO I authorship list

S1 Analysis – Objectives

S1 Objective: Obtain a confidence interval estimate for hrms on the GW signal associated with trigger(s) received from GCN

Triggered Search (n) : A search for GWBs in conjunction with non-GW astronomical observations.

† FMR: L.S. Finn, S.D. Mohanty

, J. Romano, “Detecting an association between Gamma Ray and Gravitational Wave Bursts,” Phys. Rev. D v60, p. 121101 (1999)

Approach: Combine the (weak?) GW signals from several trigger timestamps in order to improve the SNR.

[Note: averages properties of GW signals over the GRB source population]

Baseline goal: Implementation of the FMR algorithm† in the context of the three LIGO IFOs

N

iihN

h1

2rms

1


Timestamp EventID Description Right AscensionDeclination(Time Delay) H1 H2 L1

714389744 GPS HETE 2309 Probable GRB n/a No No Yes2002.08.26 09:35:31 UTC n/a714497728 GPS HETE 2310 Probable GRB n/a Yes Yes No2002.08.27 15:35:15 UTC n/a715082750.96 GPS HETE 2314 Probable X-ray Flash (XRF) 342.252 ± .5166° No Yes Yes2002.09.03 10:05:37.96 UTC -20.930 ± .0666°

1.346 ± .002 ms715157639 GPS HETE 2315 Probable GRB n/a No Marginal No2002.09.04 06:53:46 UTC n/a715262050 GPS HETE 2321 Probable GRB n/a No No No2002.09.05 11:53:57 UTC n/a715481353 GPS HETE 2328 Definitely not a GRB n/a No Yes No2002.09.08 00:49:00 UTC n/a

Coincident w/ Science Mode

6 triggers received (vs. 13 triggers for E7)

Only 1 trigger coincident with LLO-LHO lock stretch (XRF020903)!! http://space.mit.edu/HETE/spacecraft.html

S1 Analysis – Triggers Received

http://gcn.gsfc.nasa.gov/


S1 Analysis – Algorithm fora Confidence Interval Estimate

Only 1 trigger precludes direct application of FMR method (in toto).

FMR method In practice Assume stationary GW data

Calculate the cross-correlation (c.c.) statistic:

Compare A control population (“off-source”)

with A test population (“on-source”)

Data conditioning (calibration, removal of non-stationary resonances, bandpass filtering)

“off-source” data, {Xoff}

A test datapoint (“on-source”) “on-source” datapoint, Xon

llQl i

M

li

iii

,2*

1

0,1

,2,1

x~~

x~

x,xX


† F-C: G. Feldman and R. Cousins, “Unified approach to the classical statistical

analysis of small signals,” Phys. Rev. D, v57, p3873.

S1 Analysis – Where do we break from FMR?

Characterize distribution of off-source c.c. statistics as Gaussian: mean μoff, standard deviation σoff

Normalize on-source c.c. statistic by μoff, σoff

Look up interval estimate from F-C†

Revert interval estimate to appropriate units (strain)

<h1,h2> not physically meaningful yet?! Account for data conditioning effects (i.e. frequency

region removal) to obtain interval estimate on hrms

A test datapoint (“on-source”) “on-source” datapoint, Xon


S1 Analysis – Data Sets

Validatio

n Data

Off-source Data

On-source Data

Playground Data

XRF Trigger

GPS 715082750.96

L1 and H2 lock stretches courtesy of G. Gonzalez (LSU)


S1 Analysis – Interval Estimate for XRF020903

95% confidence level Interval estimate (I.E.) for <h1,h2> (from F-C, table X):

[min,max) = [0, 2.05x10-38) ← upper limit! Extrapolate to an upper limit on hrms

†:

hrms < 1.13x10-17

† for 0.465ms GWB with flat spectral density across 350-2500Hz (& no power outside this band)

burst

window

datacond

fullrms T

Ta|

BB

| maxminmaxmin h


S1 Analysis – Issues Addressed

Translation of trigger information Propagation time delay between IFOs Start of GWB relative to XRF LIGO internal DAQ time shift at XRF arrival time Absolute IFO-crossing time of XRF

Data Conditioning Possible introduction of artifacts into GW data Account for strain lost in removed frequency regions Differences in calibrations between IFOs Differences in sensitive bands for IFOs Presence of non-stationarity (before vs. after)

o Contribution of frequency resonances

Off-source population Effect of data conditioning Number of samples, time shift between samples Possible errors in μoff, σoff

On-source data Extrapolation of <h1,h2> interval estimate to (physically-meaningful) upper limit on hrms


S2 Analysis – Comparison with S1

Calibrate, bandpass filter, & remove non-stationary frequency resonances from GW data

Calibrate, bandpass filter, & remove non-stationary frequency resonances from GW data

Construct off-source distribution of c.c. statistics Construct off-source distribution of c.c. statistics

Extrapolate I.E. on <h1,h2> to I.E. on hrms Extrapolate I.E. on <h1,h2> to I.E. on hrms

Single trigger precludes FMR method being used completely

Multiple triggers(?) will allow FMR method to be used completely

Non-stationary resonances were identified using distributions of c.c. statistics

Non-stationary resonances are identified using independent methods

Used a single calibration function for both IFOs Time-dependent calibrated data available

Analysis performed mainly in Matlab® Comparison of results obtained with LDAS and with Matlab®

No estimation of systematic uncertainties Include estimates of systematic uncertainties

S1 Analysis S2 Analysis


21 triggers received (vs. 6 triggers for S1)

1 trigger with accurate direction information and coincident with LLO-LHO triple lock stretch (GRB030226) !! http://space.mit.edu/HETE/spacecraft.html

S2 Analysis – Triggers received during S2 (so far)

http://gcn.gsfc.nasa.gov/

Timestamp EventID Description Direction / Annulus{R.A., Dec., θ/2} err

(Time Delay) H1 H2 L1730220586.55 GPS GRB030225 Definite GRB {168.733, +42.050, 67.501} No Yes No2003.02.25 15:02:53.55 UTC (GCN circular #1891) unk.730266404.99 GPS GRB030226 Definite GRB {173.255, +25.899} ± 0.033 Yes Yes Yes2003.02.26 3:46:31.99 UTC HETE 10893 (GCN circulars #1879-1890) -5.9998 ± .0001ms730353261.64 GPS HETE 2603 Probable GRB Yes Yes No2003.02.27 3:54:08.64 UTC730370549.25 GPS GRB030227 Definite GRB {74.384, +20.498} ± 0.05 Yes Yes No2003.02.27 8:42:16.25 UTC INTEGRAL 214.0 (GCN circulars #1895-1907)730514316.88 GPS HETE 2608 Probable GRB Yes Yes No2003.03.01 0:38:23.88 UTC

Coincident w/ Science Mode


PRELIMINARY NUMBERS!

S2 Analysis –Interval Estimate for GRB030226

Triple coincidence – Breaks down as three cases: H1 & L1 (95% confidence level):

I.E. for <hH1,hL1>: [0, 4.33x10-41),

upper limit for hrms†: 1.50x10-19

H2 & L1 :

H1 & H2 :

† For 2.5-ms burst with flat spectral density (200-600Hz)


S2 Analysis –Future Work Needed

Multi-IFO coincident lock stretches Single- vs. Multiple-trigger analysis Using triggers with annulus directional information Optimal treatment of long-term non-stationarity Comparison/Combination of LDAS & Matlab®

implementations Accounting for systematic uncertainties

ligo-g030039-00-z external triggers circulation only within ligo i authorship list status of the...

Documents

s1 analysis triggers

ligo dcc

ligo ifos slide

authorship list lsc

source datapoint

s1 analysis algorithm

authorship list status

s1 analysis data sets