Searching for correlations in global environmental noiseKarl Wette, Susan Scott and Antony Searle

ACIGA Data AnalysisCentre for Gravitational PhysicsThe Australian National University

antony.searle@anu.edu.au

K Wette, S Scott, A Searle Searching for correlations in global environmental noise ACIGA Data Analysis 2

Outline

Global correlations impact global networks

Southern hemisphere monitoring station established

Data acquisition from LIGO, Virgo Software to handle datasets

approaching Tb

K Wette, S Scott, A Searle Searching for correlations in global environmental noise ACIGA Data Analysis 3

Global gravitational astronomy

Multiple observatories required to triangulate source and veto false alarms

Southern hemisphere detector could complete a global network

Confidence in results requires knowledge of correlated disturbances to detectors

K Wette, S Scott, A Searle Searching for correlations in global environmental noise ACIGA Data Analysis 4

Local environmental monitoring

In The ANU Gravitational Wave Research Facility Optical cleanroom on damped slab

(VRM, HPTF etc.) Not at Gingin, but still far from existing

observatories Three seismometers (XYZ)

Supplied by Dept. Earth Sciences, from the field

One down for repairs Tri-axial magnetometer (XYZ)

Off-the-shelf instrument Electrical supply voltage monitor

Locally built Australia has 60 Hz power grid

K Wette, S Scott, A Searle Searching for correlations in global environmental noise ACIGA Data Analysis 5

Local data acquisition

Outside clean-room Power supplies

Several supply different components, minimising cross-talk

Anti-aliasing filters GPS receiver

1 PPS signal Signal generator

2048 Hz locked to GPS NI ADC card

Sampling triggered by generator

K Wette, S Scott, A Searle Searching for correlations in global environmental noise ACIGA Data Analysis 6

Local data management

NI LabView software extended to write acquired channels directly to standard Frame files

Script uploads completed frames to ANUSF multi-terabyte Mass Data Storage System (MDSS)

K Wette, S Scott, A Searle Searching for correlations in global environmental noise ACIGA Data Analysis 7

Global data acquisition

Basic environmental channels are large 1 Gb, per day, per site

Important to download only needed channels, not files Use LIGOtools (getFrames) + LDAS to produce and

download an environmental monitoring RDS LIGO does not archive these channels outside science

runs, so this must be done in near real time Use Benoit’s goodwill

Data grid technologies Local work on extensions to permit distribution at

channel, not file level Future feasibility will depend on relative costs of internet

and physical (couriered tape or disk) transfer Part of major Australian data grid effort, with

astronomers and particle physicists

K Wette, S Scott, A Searle Searching for correlations in global environmental noise ACIGA Data Analysis 8

ACIGA Data Analysis Cluster

16 P4 processors 1 Tb RAID1 storage 14 Gb ECC RAM LDAS Data grid Environmental data

analysis

K Wette, S Scott, A Searle Searching for correlations in global environmental noise ACIGA Data Analysis 9

Pipeline

Accesses all data Highly parallel Runs on ACIGA Data

Analysis Cluster Produce spectrograms Automated detection of

unusual features Ensemble of statistical

tests

K Wette, S Scott, A Searle Searching for correlations in global environmental noise ACIGA Data Analysis 10

Future

UpgradeAU$10k this year for better acquisition systemPostdoc 2005-7 includes this project

AnalysisLong timescale coherencesCoherence bursts in spectrograms Impact on global astronomyVeto recommendations