Stochastic Group Review Committee Activities

1
Stochastic Group Review Committee Activities

• Warren G. Anderson
• for
• Stuart Anderson (Chair), Bruce Allen, Robert
  Schofield, Harry Ward

2
Overview

• Stochastic group is doing three searches
• IFO-IFO all-sky search
• Most mature
• Results in S1 paper
• At least three pipeline implementations
• LDAS
• LAL Apps Condor
• Matlab
• IFO-Bar all-sky search (Livingston-Allegro)
• Playground numbers now available
• Directed search
• New idea from Rai and Albert

06/06/2004
LSC Summer Meeting Boston
2
3
S2 Review

• Only IFO-IFO all-sky results
• Presented at APS, essentially same result for
  GR17
• Several pipeline level tests passed, eg
• New pipelines give consistent result as old for
  S1
• Different pipeline implementations give same S2
  results
• Hardware injections extracted correctly
• Software injections extracted correctly
• biased estimators discovered for with
  signal
• if s is included in
  estimating P
• Simulated uncorrelated data gives null result
• important to use good random number generators
  for simulations

06/06/2004
LSC Summer Meeting Boston
3
4
S2 Review (cont)

• Several unit level tests passed,
• same result doing decimation and high pass
  filtering at double precision (done)
• same result if high-pass frequency moved slightly
  (done)
• same result using 20 sec segments (not done)
• same result using calibration from 1 segment
  (done)
• same result when changing number of bins around
  correlated lines (done)
• result can change significantly for too many
  lines
• measure omega from pulsar injections
  (impractical)
• same results when limits of integration changed
  slightly (done)
• same result when FFT's not zero-padded
• Bruce has hand-waving argument that zero-padding
  not needed
• Matlab pipeline code review (Ward, Matt Evans,
  WGA)
• A few minor discrepancies, eg. unnecessary round
  off in computing mask frequencies.
• Systematics analyzed

06/06/2004
LSC Summer Meeting Boston
4
5
S3 and Beyond

• IFO-IFO all-sky pipeline stabilizing
• Unbiased estimators thought to be understood
  (WGA)
• LAL code base to be reviewed (S. Anderson, Allen,
  Schofield, WGA)
• No S2 result to be published, S3 still to be
  analyzed
• IFO-Bar all-sky search almost ready
• Pipeline still unreviewed, but similar to IFO-IFO
• Ward leads review
• S2 result available soon, only order of magnitude
  to be presented at GR17.
• Directed IFO-IFO searches
• New idea, not implemented yet (I think)
• S. Anderson leads review

06/06/2004
LSC Summer Meeting Boston
5
6
Summary

• Group has been very responsive to committee,
  despite a relative lack of grad
  students/post-docs to do the work.
• New searches (IFO-Bar, directed) will add
  exciting new dimensions to stochastic signal
  searches.
• Stochastic group placed limit of Olt102 on
  stochastic backgrounds of astrophysical (as well
  as cosmological) origin. This is already an
  astrophysically relevant result!!
• No new papers or results presented in near term,
  IFO-IFO all sky S3 result to be published.

06/06/2004
LSC Summer Meeting Boston
6