1. International Gravitational Wave Network 11/9/2008 Building an Stefan Ballmer, for the LIGO / VIRGO Scientific Collaboration LIGO G080006-00-0

2. The collaboration The LIGO Scientific Collaboration and VIRGO – Joined forces in May 2007 – Operate 5 GW interferometers at 4 different sites – Recently finished their first extended science run 1/9/2008Stefan Ballmer, Caltech2

3. 1/9/2008Stefan Ballmer, Caltech3  Adapted from “The Blue Marble: Land Surface, Ocean Color and Sea Ice” at visibleearth.nasa.gov LIGO Livingston Observatory Louisiana, USA One interferometer (4km) LIGO Hanford Observatory Washington, USA Two interferometers (4 km and 2 km arms) VIRGO Observatory Tuscany, Italy One interferometer (3km) GEO600 Niedersachsen, Germany One interferometer (600m) Ground-based Observatories of the LIGO / VIRGO collaboration

4. Interferometer Sensitivity Laser end test mass 4 km Fabry-Perot cavity recycling mirror input test mass 50/50 beam splitter Michelson Interferometer + Fabry-Perot Arm Cavities + Power Recycling (except GEO600) GW signal 6 W 300 W 20000 W 1064 nm ~10 -11 Hz -1/2 100 4000 m (Numbers for LIGO 4km)

5. 5 S5 Strain Sensitivities of LSC/Virgo GEO600 LIGO Hanford / Livingston VIRGO

6. 6 Limiting Noise Shot noise` Seismic, through Auxiliary Loop Control Noise -Acoustic coupling - Non-linear up-conversion

7. Observatory Range A standard candle: – Range to which a NS/NS binary (1.4 solar mass) is seen ant SNR of 8 LIGO: – 4km:15 Mpc – 2km:7 Mpc VIRGO:4 Mpc 1/9/2008Stefan Ballmer, Caltech7

8. S5 / VSR1 Science Run S5 started in Nov 2005 and ended Oct 2007 – LIGO collected 1 year of triple coincidence data – Duty cycle: ~75% per IFO, 53% triple coincidence GEO joined in overnight & weekend mode January 20 th 2006 in 24/7 mode May 1 st 2006 (Duty cycle: ~91%) back in overnight & weekend mode Oct. 2006 – Oct. 2007 VIRGO joint May 18 th 2007 (VSR1) – Duty cycle: 81% 1/9/2008Stefan Ballmer, Caltech8

9. Range history (LIGO) 1/9/2008Stefan Ballmer, Caltech9

10. Range history (VIRGO) 1/9/2008Stefan Ballmer, Caltech10 Main causes of horizon variations: –bad weather –‘Thermal effects’ combined with control noise –non stationarities due to alignment fluctuations

11. What’s next (short term)? Data is ‘in the can’: – See following 3 talks for some preliminary results – More to come Upgrades (Enhanced LIGO / VIRGO+) – currently under way – Factor 2-3 sensitivity improvement – See Giovanni Losurdo’s talk Observation during upgrades… 1/9/2008Stefan Ballmer, Caltech11

12. 12 Astrowatch What ? Science data run starting Nov. 2007 Science data run starting Nov. 2007 Why ? Why ? Cover the time when LIGO/VIRGO are upgrading Cover the time when LIGO/VIRGO are upgrading Galactic supernova rate about 1/50 years Galactic supernova rate about 1/50 years Who ? Who ? GEO600, LIGO H2 as upgrades permit, and bars GEO600, LIGO H2 as upgrades permit, and bars Similar to S5 running conditions Similar to S5 running conditions Image from:members.cox.net/~k5xi/summer_milky_way.jpg

13. What’s next (mid term)? GEO HF Advanced LIGO Advanced VIRGO Details in Giovanni Losurdo’s talk 1/9/2008Stefan Ballmer, Caltech13

14. Timeline 1/9/2008Stefan Ballmer, Caltech14 You are here Hanford Livingston Virgo+ LIGO+ Advanced Virgo GEO HF Advanced LIGO DSPCP Construction Commissioning Launch Transfer data data 1st Generation2nd Generation3rd Gen.

15. Conclusion 1/9/2008Stefan Ballmer, Caltech15 The LIGO / VIRGO GW observatories have – concluded their first long science run – are currently being upgraded – GEO & Hanford 2km continue data collection during this upgrade

16. 1612/14/2007