Advanced Virgo

Probing Dynamical Spacetimes
Scientific exploitation of Advanced Virgo
Nikhef SAC, April 24, 2014 - [email protected]
Outline
 Motivation
 Aim and focus
 Composition of consortium
 Requested positions versus aim
 Coherence and added value
Motivation
Einstein gravity :
G  8 T
Gravity as a geometry
Space and time are physical objects
 Gravitation
–
Least understood interaction
–
Large world-wide intellectual activity
– Theoretical: ART + QM, Cosmology
– Experimental: Interferometers on Earth and in space

Gravitational waves
–
Dynamical part of gravitation, all space is filled with GW
–
Ideal information carrier, almost no scattering or attenuation
–
The entire universe has been transparent for GWs, all the way back
to the Big Bang
Aim and focus
To Detect and Observe Gravitational Waves
Focus on 3 activities
 Scientific promise
–
Direct discovery of gravitational waves
–
Fundamental physics, cosmology and astrophysics
–
Towards gravitational wave observatories
 Bundle existing strengths
–
(astro)particle physics: experiment and theory
–
Astrophysics, astronomy and cosmology
 Multi-disciplinary physics program
R.A. Hulse and J.H.
Taylor Jr (1993)
Advanced LIGO and Virgo
First common run in 2016
Kagra joins 2020
LIGO India?
Kagra, Kamioka, Hida, Japan
Evolution of sensitivity
1st Generation interferometers
 Nominal sensitivity achieved
–
Virgo: low frequency performance
–
1.2 years of scientific data taking
–
No detection
1st Generation interferometers
 Nominal sensitivity achieved
–
Virgo: low frequency performance
–
1.2 years of scientific data taking
–
No detection
Direct discovery of GW
 Advanced Virgo
–
Improve sensitivity by factor 10
–
From Virgo cluster to Local supercluster
–
This yields a factor 1000 increase in event rate!
Astronomy: we
know GW
sources exist!
 Probable sources
–
Binary black hole coalescence
–
Binary neutron star mergers, supernovae, pulsars
 BNS Rates: (most likely and 95% interval)
–
Initial Virgo (30Mpc)
–
Advanced detectors (350Mpc)
– 1/100yr (1/500 - 1/25 yr)
– 40/yr (8 - 160/yr)
Kalogera et al.; astro-ph/0312101
 BBH more difficult to predict
Advanced Virgo
PROJECT GOALS
 Upgrade Virgo to a 2nd generation detector. Sensitivity: 10x better than Virgo
 Be part of the 2nd generation GW detectors network.
Timeline: data taking with Advanced LIGO
 Improvements
–
High quality optics
–
–
–
–
–
–
–
–
Sensing devices under vacuum
Larger beams
–
–
–
Heavier mirrors
Low absorption
Coating thermal noise
0.2 nm rms surfaces
Thermal compensation
Monolithic suspensions
Modification of UHV system
Signal recycling
...
2015 Challenge
NL contributions
Nikhef
Input Mode Cleaner
Cryolinks
Seismic attenuation systems
Linear alignment and phase camera’s
External injection bench
 Priority of commissioning
–
EIB is the last bench before laser beam enters the vacuum
–
First stage in the commissioning process
External injection bench
 SAS features
 Single-stage attenuation system
 Six degrees of freedom
 Sensors: 6 accelerometers, 6 LVDTs
 Consistent with 10-12 m/rtHz
 Compact design
 Installed and tested in Virgo
 EIBSAS was first major installation of AdV
EIBSAS: finishing touch(es)
Mathieu Blom
November 18, 2013
EIBSAS in Advanced Virgo
Laser bench
EIBSAS
Install optics: Q1 2014
Commission controls: Q2 2014
IIB
EIBSAS: new TF with
PZT driven shaker
Input mode cleaner
 IMC
–
Triangular cavity
–
High finesse, 145 m length
–
First stage in frequency stabilization
 Dihedron
–
Complex optical component
–
Manufactured by Dutch industry: Optronica
–
Also produced the end mirror(s)
Marine: zorg dat je erbij komt…
Optronica
Marinebedrijf
Den Helder
Input mode cleaner
 IMC end-mirror system
–
Mirror payload
–
Installed in Q1 2014
–
Commissioning now in progress
–
–
–
Including marionette
First optical payload installed in Advanced Virgo
Crucial to stay on timeline
Advanced Virgo
Thomas Bauer
Marko Kraan
Our first installations
incompleted
AdV
Installation
Commisioning in progress
Cryolinks
 Cryolink features

Four LN2 links: 10-10 mbar region

Designed by Nikhef

Factory acceptance completed

Installation schedule

First link in May 2014

Controls and safety systems

Completed in November 2014
Optical sensing systems
 Angular alignment

DC QPD sensing at WE (B8) and NE (B7)

RF sensing

Up to 131 MHz
 Phase camera’s
RF sensing of cavity fields

Amplitude and phase distribution

For all wave fields (i.e. side bands)
Optical sensing systems
4QUAD OPA140
100000
Shot noise limited
10000
1000
nV/SQRT(Hz)

Q2
Q3
Q1
Shot noise lightt
100
Q4
10
1
0.1
1
10
Freq [Hz]
100
Phase camera’s: 3D imaging
 Imaging of cavity fields
 Both carrier and sidebands






Martin van Beuzekom
Kazuhiro Agatsuma
f1 = 6.270 777 MHz
f2 = 56.436 993 MHz
f3 = 8.361 036 MHz
f4 = 131.686 317 MHz
f5 = 22.38
MHz
fH= 80.00
MHz
 Amplitude and phase


High speed imaging of HOM
Avoid moving parts (CCD based)
 AdV optical design: MSRC
 Main diagnostics for Advanced Virgo
 Input for Thermal Compensation Systems
Femtometer/Hz isolation
Production for AdV
SPRB
SIB2
SWEB
SDB2
SNEB
Horizontal geophones
Production for AdV
E. Hennes
A. Rietmeijer
L. Ceelie
M. Jaspers
W. Kuilman
P. de Groen
J. Soede
MultiSAS challenges
Requirement
Expected performance
Controls
Optical levers
MultiSAS schedule
National context
 National APP Strategic Plan
– Nikhef strategic plan
– PTA, eLISA, Astronomy, Theory communities
 Astrophysics at RU
– Joined Virgo in May 2012
– First Astrophysics group in Virgo
 BlackGEM Proposal
– Approved by NOVA Phase-4 Instrum. Prop.
–
–
–
Third GW meeting
Astron, Feb. 7, 2014
Design phase approved, with PHASE-I reservation
Black-hole merger GW-EM radiation array
https://www.astro.ru.nl/wiki/research/blackgemarray
Multi-messenger astronomy
 GW signal in astrophysical context
 Give precise localization
– Identify host galaxy
 Multi-messenger picture of most
energetic events
–
Insight into physics of progenitors
–
–
Mass, spin, distance
Environment: temperature, density, redshift
Received 64 applications so far ...
International context
 Nikhef – Kagra collaboration in ELiTES
–
EU funded technology transfer from Nikhef to Kagra
 Einstein Telescope
–
On ApPEC readmap; Listed as A-Topic for Horizon 2020
–
Nikhef leads JRA3 on site selection and gravity gradient noise
University of Tokyo, December 5, 2013
November 28, 2013: eLISA approved!
arXiv:1201.3621v1
GW antenna in space - eLISA
–
3 spacecraft in Earth-trailing solar orbit
separated by 106 km.
–
Measure changes in distance between
fiducial masses in each spacecraft
–
ESA funded
–
Launch date 2034
LISA pathfinder
Science goals
What happens at the edge of a Black Hole?
Chandra - Each point of x-ray
light is a Black Hole!
First model-independent precision test of strong field
dynamics of spacetime using signals from coalescing
compact binaries
Robust against unknown instrumental features
(e.g. calibration errors)
Robust against currently unknown GR effects
(e.g. neutron star tidal effects)
Expand to BBH, pure spacetime process, rich dynamics
Prompted formation of new LSC-Virgo technical subgroup, led by Del Pozzo
Is Einstein’s theory still right in
these conditions of extreme
gravity? Or is new physics
awaiting us?
Tests of post-Newtonian theory
 Test of GR without assuming alternative model
–
Based on post-Newtonian phase expansion of BBH inspiral signal
–
Single (2, 20) Msun BBH merger (zero spin): PN coefficients all
depend on only the component masses. Thus only two are
independent
–
Fit to a model where three PN coefficients are treated as
independent
–
Test non-linear predictions (e.g. tail terms, logarithmic terms)
Van Den Broeck, Li,
Del Pozzo, Vitale
Compact binary coalescence
 eLISA
–
Mass at source
–
Mass ratio
–
Spin magnitudes
–
Distance to the source
–
GW signal detected months before merger
–
Signal visible by eye in data stream
–
BH merger rate
– eLISA: from a handful up to a few hundred events per year
SNR
Test of BH uniqueness theorem
 Kerr metric is the unique end
state of gravitational collapse
 Based on assumptions

Spacetime is vacuum, axisymmetric
(stationary), asymptotically flat

There is a horizon in spacetime
 IMRI can map spacetime
–
ET can see IMRIs out to z  3
–
See few % deviation quadrupole
 BH no-hair theorem
–
Perturbed GW has QNM given by M
and S
–
Kerr relation for multipole moments
Counting polarization states
 Polarization tests are qualitative tests
 A single measurement is good enough to rule the theory out
 Only two states in GR
–
Plus and cross polarizations
 Polarization states in a scalar-tensor theory
–
Six different polarization modes
Science goals
What is the mysterious Dark Energy pulling the Universe apart?
CBC as standard
candles (sirens)
Hubble constant
Walter Del Pozzo
“Inference of cosmological parameters from
gravitational waves: Applications to second
generation interferometers”
Dark energy and matter
interact through gravity
Phys. Rev. D86, 043011 (2012)
Science goals
What powered the Big Bang?
Gravitational Waves Can Escape from
Earliest Moments of the Big Bang
neutrinos
1 second
Inflation
(Big Bang plus
10-34 Seconds)
light
Big Bang plus
380,000 Years
Now
gravitational
waves
Nature 460, 990-994 (20 August 2009)
An upper limit on the stochastic
gravitational-wave background of
cosmological origin
Big Bang plus
14 Billion Years
The LIGO Scientific Collaboration &
The Virgo Collaboration
Coherent Consortium
T. Bauer
A. Bertolini
N. Van Bakel
M. Van Beuzekom
J.W. van Holten
C. Van Den Broeck
H.J. Bulten
J. van den Brand
Optics
Suspensions
Linear alignment
Phase camera’s
Theory
CBC Analysis
CW Analysis, eLISA
Coordinator
K. Agatsuma (postdoc)
K. van Heijningen (PhD)
R. Jonker (PhD)
M. Agathos (PhD)
J. Meidam (PhD)
G. d’Ambrosi (PhD)
S. Kumar (PhD)
P. Groot
G. Nelemans
S. Ghosh (postdoc)
S. Shah (PhD)
Discovery, ET
Discovery
CW Analysis
CBC Analysis
CBC Analysis
Theory
Theory
EM connection (BlackGEM)
Sources, eLISA
Joint GW-EM studies
Joint GW-EM studies
All members bring in
relevant experience
Requested resources – projects
 Periodic sources analysis – GRID
–
H.J. Bulten (VU), R. Jonker (PhD)
 Coalescing binaries – BNS, BBH
–
C. Van Den Broeck (Nikhef), M. Agathos, J. Meidam, pd1 (3 yr), PhD1
 Advanced Virgo upgrade
–
JvdB (VU), A. Bertolini (Nikhef), N. van Bakel (Nikhef), M. van Beuzekom (Nikhef), all PhD and pd
 Stochastic background – theory and analysis
–
JvdB (VU), J.W. van Holten (Nikhef), G. d’Ambrosi (PhD), pd3 (3 yr), PhD4
 Coalescing binaries – Joint GW-EM data analysis
–
G. Nelemans (RU), C. Van Den Broeck (Nikhef), pd2 (3 yr), PhD2
 Multi-messenger analysis (BlackGEM, UC binaries)
–
P. Groot (RU), G. Nelemans (RU), H.J. Bulten (VU), PhD3
 Einstein Telescope and eLISA preparations
–
JvdB (VU), G. Nelemans (RU), A. Bertolini (Nikhef), N. van Bakel (Nikhef), pd4 (2 yr), PhD5
 Running budget
–
Annual contribution to Virgo
 Investment budget: 300 k€
–
Third generation: crystalline suspensions, sensor networks
6 year program
6 PhDs, 2 postdocs
Investment 300 k€
Added value of FOM program
 Ambitious program
–
Combines resources from universities and research institute
 Strong position at international forefront
–
Program provides focus, collaboration and coherence
 Timing and urgency: Advanced Virgo and LIGO operational in 2016
 Attractive context for advanced research
–
Excellent environment for postdocs, students, guests
–
High quality training
 Broadening of scientific experience
–
Experimental physics, analysis, GRID computing, astronomy, astrophysics,
cosmology, theory
 Organize national GW community
–
Annual Dutch GW meetings through Nikhef
 Links to other programs
–
Multi-messenger astroparticle physics (GW-EM, neutrino’s)
Outreach and social relevance
 Nikhef spin out company
–
Commercialize “Gravitational Physics” instrumentation
–
Vibration isolation
–
Sensor networks
 Outreach publications
Science Park Amsterdam
[email protected]
Shell – Nikhef collaboration agreement
 Cooperation agreement on PHASE-I.1
–
Contract signed October 16, 2013
 Specifications
HTSM 2013 - SENSEIS
 Ultra-sensitive readout electronics
– Seismic sensor networks
– MEMS sensors
– Bandwidth 1 – 100 Hz
Niels van Bakel – main PI
Nikhef
VU University Amsterdam
UT EEMCS: CTIT & MESA+
Shell
ST Microelectronics
InnoSeis
Nikhef SAC; April 24, 2014
Jo van den Brand, Nikhef and VU University Amsterdam
Backup slides
InnoSeis
 Nikhef spin out company
–
–
–
Commercialize “Gravitational Physics” instrumentation developments
–
See http://www.innoseis.com
–
Launched in 2013
Distributed wireless networks
–
Advanced sensors: e.g. accelerometers
–
Mesh network protocols
Femtometer positioning
–
Vibration attenuation systems with 106 suppression factor
Science Park Amsterdam
[email protected]
MEMS-sensor development
 Accelerometer prototype
– Sensitivity 1 ng/rtHz
– Bandwidth 1 – 200 Hz
– Electronics
– Read-out
– Force-feedback
 Sensor network
Thousands of sensors around core optics
Measure correlations with seismic field
Subtraction of gravity gradient noise
–
–
–
Actuators in MEMS
Seismic sensor demo as etched
Predicted sensitivity evolution
 Advanced detectors only
–
Joint runs: 6 months, 9 m, 1 year, 1 y
–
BNS only (BBH can double rates)
–
Kagra and Indigo will join later
–
See arXiv 1304.06
Primeordial gravitational waves
 Primeordial background
–
Quantum fluctuations produce a
background GW that is amplified by
the background gravitational field
 Stochastic background
–
Inflation
– Period of exponential growth
of the Universe
–
Phase transitions
–
Cosmic strings
– Forces of Nature splitting off
– Topological defects or
fundamental (super)strings
–
Predictions quantum gravity theories
– Pre-Big-Bang cosmology
– Brane world scenarios
– “Bounce” cosmologies
– …
Primordial stochastic background
 Wide-band sources
–
Numerous inflation models
– Approx. Harrison-Zeldovich spectrum
– Reheating to at least T needed for primordial
nucleosynthesis
– Tensor to scalar ratio r sensitive to V1/4
– For scale invariant spectrum CMB implies
that interferometers cannot access SBGW
–
Processes extend over a large
range of scale factor
–
Pre-Big Bang Cosmology
–
Cosmic string evolution
– Flat spectrum
– Topological defects
– Brane inflation models
 Peaked sources
–
Phase transitions and reheating
– Need temperatures of 106 – 107 GeV for ET
Grojean and Servant, Phys. Rev. D75, p. 043507, 2007
Advanced Detectors and the
Stochastic Background


ET
Catalog of models:
http://homepages.spa.umn.edu/~gwplotter/
“Old” constraint from
CMB temperature.
Out of reach of advanced
detectors by ~5 orders of
magnitude
55
Advanced Detectors and the
Stochastic Background


ET
Catalog of models:
http://homepages.spa.umn.edu/~gwplotter/
Rough (to be checked)
spectrum corresponding
to r = 0.2.
Out of reach of advanced
detectors by 6-7 orders of
magnitude
56
Advanced Detectors and the
Stochastic Background



ET
10 GeV
1013 GeV
Catalog of models:
http://homepages.spa.umn.edu/~gwplotter/
If inflation ends with a
preheating resonant phase,
inflaton energy is efficiently
transferred to other particles.
Can have significant
increase in GW background.
Peak depends on energy
scale.
» Easther & Lim, JCAP 0604,
010 (2006).
» Easther et al, PRL 99, 221301
(2007).
» Easther, Nucl. Phys. Proc.
Suppl. 194, 33 (2009).
57
Advanced Detectors and the
Stochastic Background



ET
Axion-based inflation models
include axion-gauge
couplings.
Gauge backreaction on the
inflaton extends inflation.
This late inflationary phase
increases GW production at
high frequencies.
» Barnaby et al, Phys. Rev. D. 85,
023525 (2012).
» Cook & Sorbo, Phys. Rev. D85,
023534 (2012).
Catalog of models:
http://homepages.spa.umn.edu/~gwplotter/
58
Consistency Relation
Need Not Hold
• The consistency relation
nt  r / 8
need not be correct.
• The tensor spectral index should be
measured, and this relation should be
confirmed or disproved.
• Various authors have suggested that
the equation of state between inflation
and radiation era could be stiff.
• If so, GW could increase with
frequency.
• Potentially detectable by
advanced detectors.
Boyle & Buonanno, PRD 78,
043531 (2008).
59
Advanced Detectors and the
Stochastic Background



Catalog of models:
http://homepages.spa.umn.edu/~gwplotter/
Cosmic (super)strings
models: cusps or kinks
moving at relativistic speeds
produce bursts of
gravitational radiation.
Integrating over the whole
universe leads to a GW
background.
Large parameter space,
some of it already probed by
initial LIGO.
» Damour & Vilenkin, PRL 85,
3761 (2000).
» Siemens et al, PRL 98, 111101
(2007).
» Olmez et al, PRD 81, 104028
(2010).
60
Advanced Detectors and the
Stochastic Background

Alternative cosmologies,
such as pre-Big-Bang
models, can lead to strong
GW backgrounds at high
frequencies.
» Gasperini & Veneziano, Phys.
Rep. 373, 1 (2003).
» Buonanno et al, PRD 55, 3330
(1997).
Catalog of models:
http://homepages.spa.umn.edu/~gwplotter/
61
Advanced Detectors and the
Stochastic Background



Catalog of models:
http://homepages.spa.umn.edu/~gwplotter/
Individual neutron star and/or
black hole pairs generate
chirp GW signals.
Integrating over the whole
universe (z<6) leads to a GW
background.
Peak in the LIGO band.
» Phinney, ApJ 380, L17 (1991).
» Ignatiev et al., MNRAS 327, 531
(2001).
» Regimbau & de Freitas Pacheco,
ApJ 642, 455 (2006).
» Wu et al, Phys. Rev. D 85,
104024 (2012).
62
Advanced Detectors and the
Stochastic Background


Neutron stars can have a
variety of instabilities: rmodes, bar-modes etc.
Integrating over the entire
universe leads to a GW
background.
» Owen et al, PRD 58, 084020
(1998).
» Lai & Shapiro, ApJ 442, 259
(1995).
» Regimbau & de Freitas
Pacheco,, A&A 376, 381 (2001).
Catalog of models:
http://homepages.spa.umn.edu/~gwplotter/
63
Advanced Detectors and the
Stochastic Background


Catalog of models:
http://homepages.spa.umn.edu/~gwplotter/
Magnetar model: protoneutron
stars in very strong magnetic
fields (1016 G) can be distorted
(high ellipticity).
Integrating over the whole
universe leads to a GW
background.
» Cutler, PRD 66, 084025
(2002).
» Regimbau & Mandic, CQG
25, 184018 (2008).
» Dall’Osso et al, MNRAS 398,
1869 (2009).
» Marassi et al, MNRAS 411,
2549 (2011).
» Wu et al, Phys. Rev. D 87,
042002 (2013).
Conclusions
• If BICEP-2 result holds up, this is really good news for us!
• We now know that it is possible to study the physics of these very
early times and high energies.
• This was not a “given”!
• Not possible with any lab-based techniques.
• Physics of inflation could be rich.
• Many processes do not leave signatures in the CMB, but
could be detectable by direct GW observations today.
• Combine CMB B-mode measurements with interferometric
SGWB measurements at different frequencies to disentangle
different models, and to really study the physics of inflation.
• BICEP-2 result is the strongest argument to build the nextgeneration GW detector dedicated to searching for SGWB.
• This story is just beginning to unfold, and we have an important role
to play!
Network
LIGO, Virgo and GEO exchange data since 2007
LISA
1st generation observational results
LISA
Outreach
Intermediair
NRC
Teleac Radio5
De Volkskrant
Kijk
Technisch weekblad
Civiele Techniek
R&D budget breakdown
Cryogenic mirror suspension R&D budget breakdown
Item
Cost estimate (kE)
Test facility upgrade
Cryocooler
40
Controls
10
Mechanics
20
Electronics
15
Fiber coupled optical sensors
15
Total
100
Components R&D
Cryogenic GAS filter
15
Sapphire Williams toggles
15
Alternative design for crystalline vertical springs
20
Sapphire suspension ribbons
50
Silicon flexures
30
Alternative materials for flexures
20
Total
150
Suspension final prototype
Cryogenic GAS filter stage and heat links
20
Crystalline suspension structure
20
Sapphire/silicon test mass
10
Total
50
RU involvement
 Eerste studies van EM-GW synergies voor Virgo (Ghosh et al), laten zien dat EM constraints op
afstand of inclinatie kan leiden tot betere parameterschatting
 Complete studie van EM-GW synergies voor eLISA binaries (Shah et al, 4 artikelen) die laten
zien dat zo'n studie alleen gedaan kan worden op een *volledige* en *representatieve* set
gesimuleerde signalen. Dat betekent dat voor de eerste Virgo studies grootschalig
moeten worden uitgebreid
 Duidelijke rol RU groep in definitie EM follow-up strategie van Virgo/LIGO (Gijs in EM
preparation committee, Paul in EM follow-up committee). Bijeenkomst in Amsterdam (1 van de
2 wereldwijd, andere in Chicago) was door ons georganiseerd. Inmiddels >60
aanmeldingen voor MoUs van EM groepen.
 Design studies voor BlackGEM hebben geleid tot een volwassen ontwerp voor de "ultieme GW
follow-up machine" waar door NOVA, RU, NWO, KU Leuven samen 3.2 M Euro voor is
uitgetrokken om te realiseren
 Compact binaries studies van Nelemans (e.g. Nissanke et al. 2012, Littenberg et al. 2013)
hebben geleid tot zijn lidmaatschap van eLISA consortium board (eerste bijeenkomst na
selectie in Amsterdam Jan 2014) en dus uitstekende posities om als NL ook in de
toekomst *zichtbaar* aan GW frontline projecten mee te doen.
 Uitnodiging Living Review Relativity te coordineren over eLISA compact binaries science
 Evt NWO-APP programma noemen? Was er denk ik niet gekomen als dit FOM programma er
niet geweest was (al is dat moeilijk aan te tonen)
GW Program Management
 Management Structure
–
Clear structure established to realize Mass and Focus
–
Initial MT composition: GN, CVDB, and JvdB (chair)
 MT tasks
–
Monitor progress in various scientific activities
–
Allocation of resources (re-discuss annually)
–
Provide steering
–
New scientific developments
–
Note: 1 PhD not allocated
–
Monitor finances
–
Outreach
 Work towards a national GW community
–
Nikhef has a role here (annual and quarterly meetings)
 Links to other programs
–
Multi-messenger astroparticle physics (e.g. with KM3Net)
Complementarities of GW detectors
Difference of 104 in wavelength:
Like difference between X-rays and IR!
Rotating
Neutron Stars
LISA
LISA will see all the compact white-dwarf and
neutron-star binaries in the Galaxy (Nelemans)
VIRGO
LIGO
Nikhef: redesign and replace dihedron
Eric Hennes
Zorg dat je erbij komt…
Optronica
Marinebedrijf
Den Helder
ET WP1 – Infrastructure
 Infrastructure: big cost items
–
Tunnels, caverns, buildings
–
Vacuum, cryogenics, safety systems
–
Collaborate with industry
– COB (Amsterdam, October 9, 2008)
– Saes Getters Italy
– Demaco Netherlands
 Input from WG2 & 3
–
Topology (Albrecht Ruediger)
–
Length of superattenuators
 Experience
–
Virgo, GEO, Gran Sasso,
Kamioka, LIGO, etc.
Advanced Virgo: vacuum – cryo links
LN2
GN2
Reinforce
rib
Fixed 300 K
Vacuum + super isolation
Isolation vacuum
Tie rod
3.2 mm/m
3.2 mm/m
LN2
Forces
Beam vacuum
LISA
Summary
 An efficient, responsive and light structure to support Virgo and
promote European collaboration under supervision by national
institutions
 EGO existence relies on Virgo/AdV success
 The future of GW in Europe depends upon a stronger
collaboration between EU countries. EGO may prefigure the
required infrastructure.
Advanced
VIRGO
Interferometers – sensitivity
The horizon (best orientation) for a binary system of two
neutron stars is 22 Mpc and of two 10 solar mass black
holes is 110 Mpc
Activity 2: Signals from inflation and phase transitions
 Theoretical (astro)particle physics community
–
GW, inflation, string theory, cosmic defects
–
Jan Willem van Holten et al. (Nikhef, Leiden)
G. Koekoek

Provide templates, spectra, etc.
–
LISA
Participate in Virgo – LIGO analysis
Galluccio et al; Phys. Rev. Lett. 79 (970)

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