Measuring the Universe with Einstein‘s Gravitaonal Waves

Prof. Dr. Karsten Danzmann

Albert Einstein Instute (AEI) and Leibniz Universität Hannover What are Gravitaonal Waves? – Distoron of space and me, propagang at the

2 The Length Change is Small!

• in nearby galaxy ⇒ Squeezing space by 10-21

⇒ 1 km baseline changes by 1/1000 of a Proton diameter (10-18 m = 1 Aometer)! ⇒ For a few milliseconds! 3 Original Interferometer of Michelson and Morley 1887

• Sensivity 1887: Δℓ= 600 pm =0, 000 000 000 6 m • Laser interferometer today: 0, 000 000 000 000 000 000 1 m/√Hz

4 Gravitaonal Wave Sources • Ground-based detectors observe in the audio band – The analogue of opcal astronomy

Audio band 1 Hz – 10 kHz World-Wide Laser Interferometric Gravitaonal Wave Detector Network LIGO GEO600

(future) LCGT

LIGO

Virgo 80m / 5 km

3 km Source: A. Lazzarini, modified LIGO: Two Sites, Three Ifos

One interferometer with 4 km Arms, one with 2 km Arms

One interferometer with 4 km Arms VIRGO: The French-Italian Project

3 km armlength near Pisa GEO600 - German-Brish collaboraon, locaon Hannover / Germany - with power and signal recycling

U Birmingham U Mallorca Glasgow 9 LIGO Hanford (USA) Largest Dedicated Computer Cluster in the World for GW Data Analysis at AEI GEO600 operated by AEI

LIGO Livingston (USA)

VIRGO (Pisa) Crab Pulsar (1054 AD)

The Astrophysical Journal, 713, p671–685, 2010: “SEARCHES FOR GRAVITATIONAL WAVES FROM KNOWN PULSARS WITH SCIENCE RUN 5 LIGO DATA” Mountains on Crab Pulsar are less than 2m high!

Present Sensivity (S5 )

• 10 Msun - 10 Msun BH - BH binaries • Event rates – Based on populaon synthesis [Kalogera’s summary of literature] merger • Inial IFO event rates – Range: 100 Mpc – 1 / 600yrs to ~3/yr

12 Future Plans : Advanced LIGO with Technology from GEO! • Observable volume several thousand mes LIGO! • Installaon 2011-15 • GEO contribuons: • New suspensions • New Opcs • 200 W lasers • Signal Recycling – Resonant Sideband Extracon Advanced LIGO and AdVirgo

• 10 Msun - 10 Msun BH - BH binaries • Event rates – Based on populaon synthesis [Kalogera’s summary of literature] merger • Inial IFO event rates – Range: 100 Mpc – 1 / 600yrs to ~3/yr merger • Advanced IFO event rates – Range: z = 0.45 – 1 / mo to ~30/day

14 Interferometer Quantum Noise

Quantum Shot Noise

Standard Quantum Limit (SQL) Interferometer Quantum Noise

[Unruh 1982] [Jaekel, Reynaud 1990]

Shot Noise

Optimised“Squeezing” of Laser Light

(SQL) Squeezed Light in Hannover 12.7 dB World Record Squeezing

r ≈0.5

r ≈1

r ≈1.5

18 T. Eberle et al., Phys. Rev. Le. 104, 251102 (2010). GEO600: The First Gravitaonal Wave Detector using Squeezed Light! Virgo and GEO Science Run S6e June 3 – Sept 5, 2011 Strain [1/sqrt(Hz)]

Frequency [Hz] 20 Astrowatch for GEO600 unl 2015

• LIGO and Virgo offline for upgrading

• GEO600 taking data 24/7

• Occasional interrupons for commissioning and upgrades

21 The Third Generation: The Einstein Gravitational Telescope E.T.

• Overall beam tube length ~ 30km • Underground locaon • Cryogenic • Squeezing • LF and HF Ifos

22 Conceptual Design Study in European Union FP7 Program

• AEI Co-PI • Kick-Off May 2008 • Final Presentaon May 20, 2011 in Cascina Arsc/Schemac views

hp://www.et-gw.eu/emages

ET event - May 2011 24 Corner and ancillary halls

hp://www.et-gw.eu/emages

ET event - May 2011 25 Laser Interferometer Space Antenna

3 Satellites 5 Million km arms 50 Million km behind Earth

Einstein 26 LISA: A Mature Concept • Aer first studies in 1980s, M3 proposal for 4 S/C ESA/NASA collaborave mission in 1993 • LISA selected as ESA Cornerstone in 1995

• 3 S/C NASA/ESA LISA appears in 1997 • Baseline concept unchanged ever since! LISA Pathfinder

• Tesng LISA Technology in Space!

28 LISA Pathfinder

• Take one LISA link • Squeeze it into one spacecra

29 Electrode Housing and Test Mass: LISA Design

30 Flight Model Units replace EMs The Spacecra

• Waing for a launch in 2014! 32 But then in March 2011...

33 LISA Redefinition Study

• Redesign for ESA-only mission • Cost-cap for ESA cost at 850 M€ plus member state contributions around 200 M€

Ø Build on LISA Pathfinder hardware Ø Shorter arms, smaller telescopes, simpler orbits, less mass Ø Can use cheaper launcher

• Still requires lots of work, but: à We can do it! Soyuz Fregat à A history class science mission! eLISA-NGO Layout

35 evolved LISA (eLISA) Science • Cosmology – Expansion of universe and Dark Energy equaon of state • Black Holes – Evoluon, seismology and bothrodesy • Precision tests of strong gravity – No-hair theorem • Galaxy mergers – History and evoluon • Structure of galaxy – Complete WD mapping and stellar evoluon • Helioseismology – Solar g-modes • Big Bang – Primordial GW radiaon

36 eLISA Science and Astronomy • Cosmology – Expansion of universe and Dark Energy equaon of state • Black Holes – Evoluon, seismology and bothrodesy • Precision tests of strong gravity – No-hair theorem • Galaxy mergers – History and evoluon • Structure of galaxy – Complete WD mapping and stellar evoluon • Helioseismology – Solar g-modes • Big Bang – Primordial GW radiaon

37 eLISA: 100 Million WD Binaries! • eLISA will hear every binary system in the Galaxy that has a period < 2 hr • About 3 000 resolvable in 2 yr – <3° locaon, 10° inclinaon, – distances down to 1 % • Of the 50 opcally known ultra-compact binaries: à8 are guaranteed calibraon sources for eLISA-NGO

38 eLISA Science and Astronomy • Cosmology – Expansion of universe and Dark Energy equaon of state • Black Holes – Evoluon, seismology and bothrodesy • Precision tests of strong gravity – No-hair theorem • Galaxy mergers – History and evoluon • Structure of galaxy – Complete WD mapping and stellar evoluon • Helioseismology – Solar g-modes • Big Bang – Primordial GW radiaon

39 Binary Black Holes at large Redshi! Contours of SNR, equal mass merger (optimal)

à

Massà 40 Trace Galaxy Evoluon through Mergers • Hierarchical structure formaon: many galaxy mergers • Most galaxies have BH in center: à Many BH mergers • Strong eLISA sources eLISA Black Hole Physics at high SNR

• BBH rest mass 104 – 107

• Out to redshi z ≈ 7

• Redshied mass to 0.1%-1%

• Absolute spin to 0.01-0.1

• Luminosity distance 1 – 50 %

• Sky locaon 3° - 10 °

42 LISA Technology for Gravity Field Missions

AEI in close collaboration with IfE Hannover and ZARM in QUEST Cluster of Excellence Gravity Recovery and Climate Experiment (GRACE)

GFZ GRACE Mission (UTCSR, GFZ, DLR, JPL). Image credit: NASA

Tiwari et al., “Dwindling groundwater resources in northern India, Velicogna, “Increasing rates of ice mass loss from the from satellite gravity observaons”, Geophys. Research Le. 36, Greenland and Antarcc ice sheets revealed by GRACE” L18401 (2009). Geophys. Research Le. 36, L19503 (2009). Groundwater loss in India Ice mass loss in Greenland GRACE Follow-On Mission Approved!

• USA/Germany, approved in Dec 2011, launch in 2016! • Laser interferometer instrument from Germany • First-ever intersatellite laser ranging instrument! • AEI: Design lead / PI for interferometry!

www.dfg-science-tv.de

Einstein 46 http://www.einsteinathome.org/

• GEO-600 Hannover • LIGO Hanford • LIGO Livingston • Current search point • Current search coordinates • Known pulsars • Known supernovae remnants

Einstein 47