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Virgo status report

Virgo status report. Gianluca Gemme INFN Genova on behalf of the Virgo collaboration. Outline. The present Scientific results Virgo Scientific Run 2 The path to 2 nd generation Advanced detectors Conclusions. The present. Thermal Noise. The Virgo detector. Stable powerful laser

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Virgo status report

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  1. Virgo status report Gianluca Gemme INFN Genova on behalf of the Virgo collaboration GianlucaGemme, Modern Problems of Laser Metrology, Lerici, Italy

  2. Outline • The present • Scientific results • Virgo Scientific Run 2 • The path to 2nd generation • Advanced detectors • Conclusions Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  3. The present Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  4. Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  5. Thermal Noise The Virgo detector • Stable powerful laser • Large and high quality mirrors • Very good seismic isolation • High vacuum Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  6. A bit of history • 1998 – 2002: Installation and commissioning of the central part • 2002 – 2003: Completion and start of commissioning of the full Virgo • 2006: control of the full interferometer at 8 W • May '07 - Sep '07: First Virgo Science Run (VSR1)‏ • Oct '07 - May '08: Diffused light mitigation • May ‘08 - Jul '09: Injection system, infrastructure and electronics upgrade; electronics upgrade; commissioning with more input power (17 W) and TCS • 7 Jul '09: Start Second Virgo Science Run (VSR2)‏ • 2010 : Monolithic suspension upgrade? Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  7. GEO600, Hanover, Germany LIGO – Hanford, WA Virgo, Pisa, Italy LIGO – Livingston, LA A worldwide network of detectors Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  8. LIGO-Virgo agreement • Early 2007, for three years • Long term spirit • Full data exchange started with VSR1 • Three sites are needed to extract more science Source pointing ability ! Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  9. Scientific results Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  10. GW sources • Transient signals • Supernovae • Compact coalescing binaries • BNS, BBH, NS-BH • “Standard candles” • Stochastic signals • Early Universe GW background • Periodic signals • Rotating neutron stars • Mechanisms producing GRB’s are likely to produce GW as well • Several GW sources are potential sources of neutrinos Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  11. Multi-messenger astronomy • Motivations • Increase confidence in GW detection • Extract more science from multiple observation of same event • Already part of LIGO and Virgo data analysis • (Long and short) GRB triggered searches • All sky search for burst signals covers supernovae • SN can be observed in other ways: electromagnetically, neutrinos • Being set up • Broaden triggered searches making use of external data • GRBs, neutrino events • Trigger fast follow-up of GW candidates • Target of opportunity observations • Wide field optical follow-up • With S6/VSR2 : begin connecting with other alert networks or provide data for immediate telescope pointing • Requires rapid online analysis, data quality flagging • Example: P5 Swift ToO • Contacts with High Energy Neutrino detectors, pointing telescopes • Connection with Astroparticle community Procedures for establishing external collaborations Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  12. Some results from LIGO-Virgo • An Upper Limit on the Amplitude of Stochastic Gravitational-Wave Background of Cosmological Origin (LSC) • Joint searches for GRBs (LV) • GRB 070201 (LSC) • Crab spindown limit (LSC) and Vela (in perspective) Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  13. Stochastic Background (SB) • A stochastic background can be • a GW field which evolves from an initially random configuration: cosmological background • the result of a superposition of many uncorrelated and unresolved sources : astrophysical background • Typical assumptions • Gaussian, because sum of many contributions • Stationary, because physical time scales much larger than observational ones • Isotropic (at least for cosmological backgrounds) If these are true, SB is completely described by its power spectrum Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  14. Isotropic search: results • Indirect BBN and CMB bounds surpassed • We are beginning to probe models Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  15. Joint LIGO/Virgo Search for GRBs • Gamma Ray Bursts (GRBs) - brightest EM emitters in the sky • Long duration (> 2 s) bursts, high Z  progenitors are likely core-collapse supernovae • Short duration (< 2 s) bursts, distribution about Z ~ 0.5  progenitors are likely NS/NS, BH/NS, binary merger • Both progenitors are good candidates for correlated GW emissions! • 212 GRBs detected during S5/VSR1 • 137 in double coincidence (any two of LIGO Hanford, LIGO Livingston, Virgo) • No detections, we place lower limits on distance assuming EGW= 0.01 Mc2 Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  16. GRB 070201 Refs: GCN: http://gcn.gsfc.nasa.gov/gcn3/6103.gcn3 X-ray emission curves (IPN) M31The Andromeda Galaxy by Matthew T. Russell Date Taken:10/22/2005 - 11/2/2005Location:Black Forest, COEquipment RCOS 16" Ritchey-ChretienBisque Paramoune MEAstroDon Series I FiltersSBIG STL-11000M http://gallery.rcopticalsystems.com/gallery/m31.jpg Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  17. Inspiral Exclusion Zone 25% 50% 75% 90% 99% GRB070201: Not a Binary Merger in M31! Abbott, et al. “Implications for the Origin of GRB 070201 from LIGO Observations”, Ap. J., 681:1419–1430 (2008). • Inspiral (matched filter) search: • Binary merger in M31 scenario excluded at >99% level • Exclusion of merger at larger distances • Burst search: • Cannot exclude an SGR in M31 • SGR in M31 is the current best explanation for this emission • Upper limit: 8x1050 ergs (4x10-4 Mc2) (emitted within 100 ms for isotropic emission of energy in GW at M31 distance) Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  18. The Crab Pulsar: Beating the Spin Down Limit! • Remnant from supernova in year 1054 • Spin frequency nEM = 29.8 Hz •  ngw = 2 nEM = 59.6 Hz • observed luminosity of the Crab nebula • accounts for < 1/2 spin down power • spin down due to: • electromagnetic braking • particle acceleration • GW emission? • early S5 result: h < 3.9 x 10-25 ~ 4X below • the spin down limit • ellipticity upper limit: e < 2.1 x 10-4 • GW energy upper limit < 6% of radiated • energy is in GWs Abbott, et al., “Beating the spin-down limit on gravitational wave emission from the Crab pulsar,” Ap. J. Lett. 683, L45-L49, (2008). Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  19. VSR2 sensitivity for CW searches Targeted searches Vela spin-down limit in ~80 day Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  20. VSR2 Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  21. Reduction of noise at low frequency Noise close to design and well understood  Important step towards next generation detectors • Low frequency • Some environmental • Some scattering • Laser bench resonances • Actuator noise • No control noise! • Medium frequency • Mirror thermal noise • Shot noise • Detection bench resonances • TCS radiation pressure? • High frequency • Shot noise May 2007 July 2009 Sensitivity at VSR1 start (black) and VSR2 start (red) Environmental noise (diffused light / beam jitter) Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  22. Range for (1.4,1.4) MBNS Horizon May 2007 ~ 3 Mpc July 2009 ~ 8 Mpc Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  23. VIRGO VSR2 • July 7 2009 – end of 2010 • Long locks: ~20 locks > 40 hours; Longest lock 143 hours long • P = 17 W • horizon ~ 8 Mpc • glitch rate ~ • 10 times lower than VSR1 Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  24. Robustness Locking duty cycle : 89.4% Science Mode duty cycle: 84.7% Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  25. The path to 2nd generation Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  26. Virgo+ • Do “easy”, “quick”, and “cheap” yet significant upgrades within unchanged infrastructure • e.g. increase laser power • Aim at a factor ~2 improvement • An order of magnitude in the reachable volume of the Universe • Make detection plausible if not likely • Include a few challenging techniques that will be needed for Advanced LIGO and Advanced Virgo • A step taken toward 2nd generation detectors • Leverage pioneering work done at GEO • Monolithic suspensions in Virgo+ Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  27. Virgo+ • Increase input power • Laser amplifier  50 W • New input mode-cleaner mirror • Thermal compensation system • Improve thermal noise • Monolithic suspensions • Dedicated shutdown(s) for installation during VSR2 • Change mirrors for higher cavity finesse at the same time • Cut down on environmental noises • New control electronics Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  28. Advanced detectors Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  29. LIGO - Virgo eLIGO - Virgo+ AdvLIGO - AdvVirgo Advanced detectors A factor 10 on the sensitivity  A factor 1000 on the rate of events  1 year of initial detectors < 1 day of advanced detectors ! • Rate of detectable binary neutron stars coalescences • Initial detectors: ~ 1/100 years • Advanced detectors: ~ 10/year • Binary black hole coalescences • Similar rates expected • Visible up to ~ 1 Gpc ! • Pulsars • Limit on ellipticity  ~10-8 Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  30. Low frequencies: seismic noise Low frequencies: wire thermal noise High frequencies: shot noise Mid frequencies: mirror thermal noise Achieving the sensitivity goal Achieving a sensitivity 10x better is ambitious. Act on different noise sources: new ideas and a wide R&D program have been necessary Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  31. Advanced Virgo • Dual recycling • Heavier mirrors, larger beams • High laser power (200 W) • Thermal compensation • DC readout • Monolithic suspensions • Vacuum improvement Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  32. AdV planning • Baseline design available • Planned shutdown for AdV installation: mid 2011- March 2014 • Commissioning: March 2014 – end of 2014 • Scientific data run: mid 2015 Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  33. conclusion Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

  34. Conclusion • Robust interferometer • 95% Science Mode duty cycle • Good sensitivity • Stable horizon: 8-8.5 Mpc (1.4-1.4 Ns-Ns) - averaged 42-44 Mpc (10-10 BH-BH) - averaged • Low glitch rate: factor 10 lower than VSR1 • Preparing for installation of monolithic suspensions • LIGO and Virgo striving for first GW detection • Initial detectors have taken data at design sensitivity • Interesting upper limits derived • Enhanced detectors almost ready to take data with increased sensitivity • Advanced detectors on track Gianluca Gemme, Modern Problems of Laser Metrology, Lerici, Italy

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