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LIGO and GriPhyN

LIGO and GriPhyN. Caltech. USC/ISI. Carl Kesselman Ewa Deelman Sachin Chouksey. Roy Williams Peter Shawhan Albert Lazzarini Kent Blackburn. LIGO Virtual Data Grid. LIGO Hanford. MIT. LIGO Livingston. Caltech. Pictures. LIGO Overview.

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LIGO and GriPhyN

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  1. LIGO and GriPhyN Caltech USC/ISI Carl Kesselman Ewa Deelman Sachin Chouksey Roy Williams Peter Shawhan Albert Lazzarini Kent Blackburn

  2. LIGO Virtual Data Grid LIGO Hanford MIT LIGO Livingston Caltech LIGO Scientific Collaboration

  3. Pictures LIGO Scientific Collaboration

  4. LIGO Overview • To detect gravitational waves predicted by Einstein’s theory of relativity. • Waves created from • Rapidly spinning asymmetric compact objects eg. pulsars • Mergers of black holes, neutron stars -- gamma bursts? • Supernova collapse (and post-collapse R-modes) • Starquakes in neutron stars • Primæval GW from early universe • Installation in Louisiana and Washington State • Other projects: Virgo (Italy), GEO (Germany), Tama (Japan) LIGO Scientific Collaboration

  5. time Merger Ringdowns Primeval GW Background Supernova frequency CW (eg pulsar) Mergers BH/NS Physics and Virtual Data Each source type has different freq/time charactaristics  different virtual data requirements LIGO Scientific Collaboration

  6. LIGO Data • Time series, 16 kHz down to 1 Hz • ~1000 channels: • Gravity wave • seismic, magnetometer, microphone, engineering, … • Power spectra, cross spectra, sonogram, … • Events • Each has time and SNR (signal to noise ratio) • Candidate inspiral events from matched filter • Other pattern matching • “Examine the big ones, histogram the small ones” LIGO Scientific Collaboration

  7. detector filter reduce events objects pattern matching HEP LIGO vs NVO vs HEP • Processing • Network • NVO is federation, LIGO is coincidence • In both cases registration is important detector filter reduce events RDBMS datacube pattern matching LIGO, NVO 1D,2D LIGO Scientific Collaboration

  8. Data Access • LDAS (Ligo Data Analysis System) • Script (Tcl) based • Primarily for onsite analysis and archiving • Talks to local files, Hanford/Livingston • Has a filtering language • stack-based, like Matlab • functions eg power spectrum, fft, resample • LARS • Can talk to local, HPSS files • Can do subsetting • Simple program, simple protocol LIGO Scientific Collaboration

  9. Activities • Virtual Data • A: Language & Architecture • Naming is Time/Channel/Transformation • Smart subsetting • B: LigoVista web display • Archive at-a-glance + drill-down • Replication • A: Realtime mirror • Hanford/Livingston/Virgo nternational coincidence study • B: Fault-tolerant mirror • from Caltech to UW/Milwaukee • Pulsar search • backfill on Condor farms LIGO Scientific Collaboration

  10. 1A: Virtual Data: Language • Virtual Data: • Times + Channels, • eg 668371475-668372499 (GPS time, seconds since 1981) • L0: PEM-LVEA_SEIS*, L1:LSC-AS_Q • Transformations to Virtual Channels • eg. L0:PEM-EX-SEISX- L0:PEM-LVEA-SEISX / resample(L1:LSC-AS_Q, 1, 64) • Use LARS and Globus Replica Catalog • For each requested data value, need to • Determine if it is instantiated; if so, where; if not, how to compute it • Plan data movements and computations required to obtain all results • Execute this plan LIGO Scientific Collaboration

  11. LIGO Application Channel, start time, stop time Virtual Data URL Request Manager Replica Selection Replica Management existing in development LARS Prot. LDAP GridFTP FTP planned Connectivity HPSS at Caltech Other Remote Storage Replica Catalog Transfor- mation Catalog Derived Data Catalog “local” storage 1A: Virtual Data: Architecture Power spectrum of seismic channels P. Charlton LIGO Scientific Collaboration

  12. 1B: Virtual Data: LigoVista • Overview of archive in a web browser • Time based • month, week, day, hour, .... • Machine state • lock status, science run, event density, .... • Drill down to raw data • Transformed data • Uses Virtual Data framework • compute on the fly and cache LIGO Scientific Collaboration

  13. 2A: Replication:Realtime • Look for coincidence in Ligo-Virgo data LDAS analysis event stream Interferometer, seismic. etc Interferometer, seismic. etc streaming bidirectional transatlantic replication Virgo LIGO LIGO Scientific Collaboration

  14. 2A: Whistlers from Lightning? LIGO Scientific Collaboration

  15. 2B: Replication: Fault-tolerance • Master archive replicated at LSC sites • Fault tolerant GridFTP HPSS@Caltech Beowulf@UWiscMilwaukee Replication API Replica Catalog Penn State UT Brownsville LIGO Scientific Collaboration

  16. 3. Pulsar Search Frequency modulation by Earth movement • Infinite computation on finite data! • Tiny, precise signals in deep noise • Search on 4D space: sky position, pulsar frequency, spindown, 0.5 TByte “image” Condor farms 6 months data UT Brownsville UW Milwaukee Caltech CACR UW Madison frequency bins Frequency (Hz) Time (months) frequency frequency time LIGO Scientific Collaboration time

  17. frequency frequency time time LIGO Scientific Collaboration

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