Transcript Slides - Agenda INFN

LNF
February 10, 2010
The Search
for Gravitational Waves
Eugenio Coccia
U. of Rome “Tor Vergata” and INFN
Gravity is a manifestation of spacetime curvature induced by mass-energy
10 non linear equations in the unknown g
ds2=gdxdx
Weak field approximation
o
g  g
 h
h 1
The Einstein equation in vacuum becomes
h  0
Having solutions
h t  x /c
Spacetime perturbations, propagating
in vacuum like waves, at the speed
of light : gravitational waves
Gravitational waves are strain in space propagating with the speed of light
Main features
• 2 transversal polarization states
• Associated with massless, spin 2 particles
(gravitons)
• Emitted by time-varying quadrupole mass moment
no dipole radiation because of conservation laws
2
dE 2G Ý
2
G Ý
Ý
Ý
Ý

 3 
d 

5 Q  ...


dt 3c
45c
Ý
Ý
d  i mi x i  d  0
Qij 
 x x
2G Ý
hij (t)  4 QÝij (t  r /c)
rc
i
3
d
x
j
PSR1913+16: GWs do exist
•
•
•
•
Pulsar bound to a “dark companion”, 7 kpc
from Earth.
Relativistic clock: vmax/c ~10-3
GR predicts such a system to loose energy via
GW emission: orbital period decrease
Radiative prediction of general relativity
verified at 0.2% level
P (s)
27906.9807807(9)
dP/dt
-2.425(10)·10-12
dw/dt (º/yr)
4.226628(18)
Mp
1.442 ± 0.003 M
Mc
1.386 ± 0.003 M
Nobel Prize 1993: Hulse and Taylor
• No laboratory equivalent of Hertz experiments for production of GWs
Luminosity due to a mass M and size R oscillating at frequency w~ v/R:
2 6
2G Ý
GM
v
Ý2 
L  5 QÝ
2 5
5c
Rc
Q  MR2 sin w t
M=1000 tons, steel rotor, f = 4 Hz
L = 10-30 W
Einstein: “ .. a pratically vanishing value…”
Collapse to neutron star 1.4 Mo
L = 1052 W
h ~ W1/2d-1; source in the Galaxy h ~ 10-18 , in VIRGO cluster h ~ 10-21
Fairbank: “...a challenge for contemporary experimental physics..”
• GWs are detectable in principle
The equation for geodetic deviation is the basis for all experimental attempts to
detect GWs:
2

h jk k
d 2l j
1
k
2  R joko l 
2 l
dt
2 t
• GWs change (l) the distance (l) between freely-moving particles in empty
space.
They change the proper time taken by light to pass to and fro fixed points in
space
In a system of particles linked by non gravitational (ex.: elastic) forces, GWs
perform work and deposit energy in the system
L
h
L
L
L
Beam splitter
Photo detector
Ý(t)
Ý(t)   1xÝ(t)  w02x(t)  hÝ
xÝ
2
Gravitational radiation is a tool for astronomical observations
GWs can reveal features of their sources that cannot be learnt by
electromagnetic, cosmic rays or neutrino studies (Kip Thorne)
- GWs are emitted by coherent acceleration of large portion of matter
- GWs cannot be shielded and arrive to the detector in pristine condition
Coupling constants
strong
e.m.
weak
gravity
0.1
1/137
10-5
10-39
GW emission: very energetic events but almost no interaction
• In SN collapse  withstand 103 interactions before
leaving the star, GW leave the core undisturbed
• Decoupling after Big Bang
– GW ~ 10-43 s (T ~ 1019 GeV)
– ~ 1 s (T ~ 1 MeV)
– γ
~ 1012 s (T ~ 0.2 eV)
Ideal information carrier,
Universe transparent to GW all the way back to the Big Bang!!
SUPERNOVAE.
If the collapse core is non-symmetrical,
the event can give off considerable
radiation in a millisecond timescale.
Information
Inner detailed dynamics of supernova
See NS and BH being formed
Nuclear physics at high density
SPINNING NEUTRON STARS.
Pulsars are rapidly spinning neutron
stars. If they have an irregular shape,
they give off a signal at constant
frequency (prec./Dpl.)
Information
Neutron star locations near the Earth
Neutron star Physics
Pulsar evolution
COALESCING BINARIES.
Two compact objects (NS or BH)
spiraling together from a binary orbit
give a chirp signal, whose shape
identifies the masses and the distance
Information
Masses of the objects
BH identification
Distance to the system
Hubble constant
Test of strong-field general relativity
STOCHASTIC BACKGROUND.
Random background, relic of the early
universe and depending on unknown
particle physics. It will look like noise
in any one detector, but two detectors
will be correlated.
Information
Confirmation of Big Bang, and inflation
Unique probe to the Planck epoch
Existence of cosmic strings
Relic Stochastic Background
Relic gravitons
Relic neutrinos
CMBR
• Imprinting of the early expansion of the universe
• Correlation of at least two detectors needed
The search for gravitational waves
f

method
sources
10-16 Hz
109 ly
Anisotropy of CBR
- Primordial
10-9 Hz
10 ly
Timing of ms pulsars
- Primordial
- Cosmic strings
10-4 - 10-1
Hz
0.01 - 10
AU
Doppler Tracking of
spacecraft
Laser interferometers
in space
LISA
- Bynary stars
- Supermassive BH (103 -107 Mo)
formation, coalescence, inspiral
10 - 103 Hz
300 - 30000
km
Laser interferometers
on Earth
-Inspiral of NS and BH binaries
(1-1000 Mo)
- Supernovae
- Pulsars
LIGO, VIRGO, GEO,
TAMA
103 Hz
300 km
Cryogenic resonant
detectors
ALLEGRO, AURIGA,
EXPLORER, NAUTILUS
- NS and BH binary coalescence
- Supernovae
- ms pulsars
Some perspective: 40 years of attempts at detection:
Since the pioneering work of Joseph
Weber in the ‘70, the search for
Gravitational Waves has never
stopped, with an increasing effort of
manpower and ingenuity:
‘70: Joe Weber
pioneering work
‘80-’10: Cryogenic
Resonant Bars
‘00 - : Large Interferometric
Detectors
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2010
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Over the years, techniques and sensitivities varied greatly, but since the start
it has been clear that to detect gravitational waves we need a NETWORK
The GW
Detectors
Network - 2010
AURIGA
The International Network
of GW Detectors
INFN- LNL, Italy
Bar detector
ALLEGRO
Baton Rouge LA
1 Bar detector
EXPLORER
INFN- CERN
Bar detector
shut down
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2010
NAUTILUS
INFN LNF, Italy Bar
detector
GW hunters are heirs
to several great traditions:
- high precision mechanical experiments (Cavendish, Eotvos, Dicke..)
detection of weak forces applied on mechanical test bodies
- precision optical measurements (Michelson, laser developpers…)
- operation of ultraprecise measurement systems (microwave
pioneers of World War II,)
- very low temperature physics (K. Onnes,…)
superfluids and superconductors technology
MiniGRAIL
The Netherlands
Allegro, USA
Schenberg,
Brazil
Explorer
Switzerland
Auriga,
Italy
Nautilus, Italy
Niobe
Australia
www.lnf.infn.it/esperimenti/rog
EXPLORER
CERN - GENEVA
NAUTILUS
LNF - FRASCATI
Bar Al 5056
M = 2270 kg
L = 2.97 m
Ø = 0.6 m
A= 915 Hz @ T = 3 K
Cosmic ray detector
Bar Al 5056
M = 2270 kg
L = 2.91 m
Ø = 0.6 m
A=935Hz @
T=3K
(T=130mK with dilution refrigerator)
Cosmic ray detector
EXPLORER
NAUTILUS
EXPERIMENTAL CONFIGURATION
Vp
Rp
Cd
Antenna
M
Capacitive
transducer
Al 5056
mt = 0.75 kg
t= 916 Hz
Ct = 11 nF
E = 5 MV/m
L0
Superconducting
Low-dissipation
Transformer
Lo=2.86 H
Li=0.8H
K=0.8
Li
dc-SQUID
Ms = 10 nH
n= 3 ·10-6 o/Hz
Quantum technology
3He-4He
Dilution Refrigerator
The liquid (the concentrated 3He phase) is lighter and
floats on a 4He sea, in equilibrium with the 6.5%
“vapor”. When 3He passes from the low entropy
liquid to the vapor phase (high entropy) it expands
and absorbs heat.
Mixing chamber
3He
out
3He
4He

Q
He-3 / He-4 mixing chamber for an ultralow temperature gw antenna.
E. Coccia, I. Modena
Cryogenics 31:712-714,1991.
NAUTILUS
Largest masses cooled
below 0.1 K
Quantum technology
Ib
Io
dc-SQUID
Io
L
Lin
• superconducting loop with
inductance L
• 2 Josephson
junctions:critical current Io ,
shunt resistance R,
capacitance C,
• Input inductance Lin,
coupling 
Resistors
Josephson
junction
V
Experimental flux noise spectral density
Carelli
et al. 98
-5
10
T=4.2 K

-6
n (0 Hz)
10
=28 h
10-7
T= 0.9 K
 = 5.5 h
10-8 -2
10
10-1
100
101
102
103
The rosette capacitive transducer
gap=9m
104
Increasing the bandwidth of resonant gravitational antennas: The Case of Explorer.
P. Astone et al. (ROG Collaboration)
Phys.Rev.Lett.91:111101,2003.
First cooling below 0.1-K of the new gw
antenna Nautilus of the Rome group.
P. Astone et al. 1991.
Europhys.Lett.16:231-235,1991.
The gw detector NAUTILUS operating
at T = 0.1-K.
P. Astone et al..
Astropart.Phys.7:231-243,1997.
DATA TAKING DURING THE LAST 18 YEARS
EXPLORER
1990 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08
Coincidence Runs
NAUTILUS
Major upgrades
IGEC1
01
03
04 IGEC2
96 97 98 99 00 01 02 03 04 05 06 07 08
> 70% duty cycle
> 90% duty cycle
EXPLORER and NAUTILUS
present sensitivity
EXPLORER
Calibration
signal
NAUTILUS
ALLEGRO (LSU) - AURIGA - EXPLORER - NAUTILUS
• Prima analisi nel 2005:180 giorni da Maggio a Novembre 2005. Ricerca di coincidenze triple.
Nessuna coincidenza trovata su un fondo di 1 evento/ secolo (PRD_76_102001)
• Seconda analisi: 515 giorni di osservazione dal 16 Novembre 2005 al 14 Aprile 2007. Ricerca di
coincidenze triple e quadruple. Nessuna coincidenza trovata su un fondo di 1 evento / secolo
Copertura completa
Analisi effettuata sul 94% del
tempo di osservazione
dal 2008 in funzione solo le 3 barre INFN
2009
EXPLORER
NAUTILUS
NAUTILUS
Duty Cycle
~ 95 %
Liquid Helium
Refillings
Days of April 2005
DAY
Definition of event
energy
threshold
time
•Because of the inherent weakness of GW signals,
and the difficulty in distinguishing them from a myriad of
noise sources, the direct detection of a gw burst require
coincident detection by multiple detectors with uncorrelated noise.
nc  N1,N 2
•Background: expected number of coincidences <n>,
during the observation time T
N1 N 2t
n 
T
This background can be measured: one shifts the time of occurrence
of the events of one of the two detectors for a number of times, and
takes the average
Detectable signals today
BURSTS: Black Hole (M~10Mo) formation, 10-4Mo into GW
2 10 44 Hz 1   f

3 10kpc  


SNR  6  10
2
 r  
h˜
1Hz 
SPINNING NEUTRO N STARS: Non axisymmetric (~10-6)
pulsar, M~1.4Mo
2
10 44 Hz 1   Tobs 
10kpc  


 6 
SNR  30
 r  



1y

h˜ 2
10

COALESCING BIN ARIES: Inspiraling NS-NS system,
M~1.4Mo
2 10 44 Hz 1   f


3 10kpc  


SNR  10
 r  
h˜ 2
1Hz 
STOCHASTIC BACK GROUND: 2 detectors, at distance
d<<GW
2
3 
1/ 2  1y 1/ 2
˜

h
f
1Hz




1,2




 GW  2  10 3
900Hz  10 22 Hz 1/ 2    f  Tobs 
Some Historical papers
Long term operation of the Rome 'Explorer' cryogenic gravitational wave detector
P. Astone et al. (ROG Collaboration)
Phys.Rev.D47:362-375, 1993.
Upper limit for a gravitational-wave stochastic background
with the EXPLORER and NAUTILUS resonant detectors
P. Astone et al. (ROG Collaboration)
Phys. Lett. B 385, 421-424 (1996).
Upper limit for nuclearite flux from the Rome gravitational wave resonant detectors
P. Astone et al. (ROG Collaboration)
Phys.Rev.D47:4770-4773, 1993
Increasing the bandwidth of resonant gravitational antennas: The Case of Explorer.
P. Astone et al. (ROG Collaboration)
Phys.Rev.Lett.91:111101,2003.
Cosmic rays observed by the resonant gravitational wave detector NAUTILUS
P. Astone et al. (ROG Collaboration)
Phys.Rev.Lett.84:14-17, 2000.
Search for correlation between GRB's detected by BeppoSAX and the gw detectors
EXPLORER and NAUTILUS
P. Astone et al. (ROG Collaboration)
Phys.Rev.D66:102002, 2002.
Cosmic ray interaction
in the bar
Excitation of the longitudinal modes
of a cylindrical bar
Thermo-Acoustic Model:
the energy deposited by the
particle is converted in a local
heating of the medium:
A resonant gw detector used as a
particle detector is different from
any other particle detector
T 
p  g
E
V0
E
 CV 0
g 
Y
C
g = Gruneisen “constant”
Burst event for a present bar: a millisecond pulse, a signal made by a few
millisecond cycles, or a signal sweeping in frequency through the detector
resonances. The burst search with bars is therefore sensitive to different kinds
of gw sources such as a stellar gravitational collapse, the last stable orbits of an
inspiraling NS or BH binary, its merging, and its final ringdown.
Real data: the arrival of a cosmic ray shower on NAUTILUS
Unfiltered
signal (V2)
The signal
after filtering
(kelvin)
Time of arrival
uncertainty ~ 1 ms
Detector calibration - Deviation from Newton law
Evaluation and preliminary measurement of the interaction
of a dynamical gravitational near field with a cryogenic
gravitational wave antenna.
P. Astone et al. (ROG Collaboration)
1991.
Z.Phys.C50:21-29, 1991,
Gm

r
r/

EXPLORER,
Ce
(1999)
V   J.of Phys.
1 
The EXPLORER/NAUTILUS SEARCH FOR SHORT GW BURSTS
1998 931 hours; CQG 18, 43 (2001)
2001 2156 hours; CQG 19, 5449 (2002)
2003 3677 hours; AMALDI 6, CQG 23, S169 (2006)
2004 5196 hours; AMALDI 7, CQG 25:114048 (2008)
1997- 2000 IGEC search Phys. Rev. Lett. 85, 5046 (2000)
Phys.Rev. D68:022001 (2003).
2005
IGEC2 search, Phys.Rev. D76:102001 (2007)
2006 - 2007 IGEC2 search, to be submitted to Phys. Rev. D
RESULTS
Sidereal time
Solar time
Events
Probability
*= coincidences
_______= accidentals
EXPLORER- NAUTILUS COINCIDENCES vs time
2001
2003
2004
DIRECTIONALITY
INTERFEROMETER
BAR DETECTOR
Sidereal hour 4.3
RESONANT DETECTORS
AURIGA, EXPLORER and NAUTILUS in continuous operation:
 continuous search for strong galactic sources with specific attention
to the periods not covered by long arm interferometers.
IGEC2 search for burst signals includes ALLEGRO up to march 2007:
• analysis of November 2005 – December 2006 at final tuning stage
(1 false alarm/century)
fourfold coincidence 244 days (59%)
threefold coincidence 388 days (94 %)
• previous search on May-November 2005 published:
Phys.Rev.D76 (2007) 102001 gr-qc 0705.0688
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2010
h (Hz-1/2)
-18
10
Pulsars
hmax – 1 yr integration
-19
10
1st generation detectors
LIGO
Credit: P.Rapagnani
Virgo
-20
10
BH-BH Merger
Oscillations
@ 100 Mpc
GEO
-21
10
Core Collapse
@ 10 Mpc
QNM from BH Collisions,
100 - 10 Msun, 150 Mpc
QNM from BH Collisions,
1000 - 100 Msun, z=1
Resonant
antennas
BH-BH Inspiral, 100 Mpc
-22
NS-NS Merger
Oscillations
@ 100 Mpc
10
BH-BH Inspiral,
z = 0.4
NS, =10-6 , 10 kpc
-23
10
NS-NS Inspiral, 300 Mpc
-24
10
1
10
100
1000
4
Hz
10
Planning
You are here
´06 ´07 ´08 ´09 ´10 ´11
Virgo
Virgo+
GEO
´12 ´13 ´14 ´15 ´16 ´17 ´18 ´19 ´20 ´21 ´22
Advanced Virgo
GEO HF
LIGO
Hanford
Livingston
Advanced LIGO
LIGO+
Launch Transfer data
LISA
E.T.
DS
PCP
Construction Commissioning
data
48
• EXPLORER - NAUTILUS
- 95% duty cycle
- monitor of gw sources in the Galaxy
- data validated by cosmic ray acoustic effect
- study of coincidences in long runs
From the VIRGO / LIGO detectors status
1960 - 2006
Given the uncharted territory that gravitational-wave detectors are probing
unexpected sources may actually provide the first detection.
2006 Only new high sensitivity detectors can provide the first detection and open the
GW astronomy
The contribution of Resonant Bars has been essential in establishing the field, giving
some intriguing results and putting some important upper limits on the gravitational
landscape around us, but now the hope for guaranteed detection is in the Network
of long arm interferometers.
TAMA, a 300 m arms interferometer at Mitaka, in
Japan, started to operate in 1998. In the same period of
time, the GEO detector, a 600 m interferometer, was
being built in Hannover, in Germany.
The experience gained with these machines has been useful for the development of kmsize detectors: LIGO and Virgo
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The Large Interferometer Network - 2010
LIGO Hanford, 4 km:
2 ITF on the same site
GEO, Hannover, 600 m
TAMA, Tokyo, 300 m
Virgo, Cascina, 3 km
LIGO Livingston, 4 km
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Interferometers use laser light to
compare the lengths of two
perpendicular arms
Principle of operation
h
(L  L)  (L  L)
L
2
L
L
L
When the wave arrives, the two
arms respond differently, they are
no longer the same length, and
so the two beams are no longer
in phase, producing a shift in the
interference fringes.
L
Beam splitter
Photo detector
The simplest design, originated by Michelson, uses light that passes
up and down each arm once.
Real detectors are designed to store the light in each arm for longer
than just one reflection: it is optimum to store the light for half of the
period of the GW
Ex.
200 Hz wave, stor~ 3 ms, L=1000 Km
This impracticality has led to the development of schemes for folding a
Long optical path into a shorter length:
delay lines ; Fabry-Perot cavities
A real detector scheme
Vacuum: 10-9 mbar
Isolation from
ground vibrations
3-4 km long Fabry-Perot
cavities: lengthen the
optical path to 100 km
10-20 W Laser
Power recycling mirror:
increase the light power
to 1 kW
Input optics
large fused silica mirrors
(low thermal noise)
A GW interferometer as an active null experiment
The large magnitude of the low frequency seismic noise makes
A “passive” interferometer design unworkable.
The key is to use feedback to keep the interferometer fixed at a
chosen operating point (fixed power of a fringe)
Needed:
Sensor, producing an error signal measuring how far you are from
The desired operating point
Actuator, a device that takes the error signal as input and that
supplies the feedback influence to bring it toward this point
Take as the output of the detector not the output power (held near a
fixed level) but the strength of the feedback influence necessary to
hold the system at the operating point
25
26
A Gravitational Interferometer Intrinsic Noise Summary
Strain Spectral
Amplitude (Hz)-1/2
Seismic
Passive and
Active
Attenuators
Thermal
Low
dissipation
materials for
mirrors and
suspensions
Shot
High Laser
Power,
Signal
Recycling
Techniques
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Frequency (Hz)
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1st GENERATION DETECTORS
1ST GENERATION INTERFEROMETERS CAN
DETECT A NS-NS COALESCENCE
AS FAR AS VIRGO CLUSTER (15 MPc)
BUT THE EVENT RATE
IS TOO LOW !!
EXPECTED EVENT RATE:
0.01-0.1 ev/yr (NS-NS)
FIRST DETECTION:
POSSIBLE BUT UNLIKELY
eLIGO & VIRGO+
VSR2-S6 Run
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VSR2-S6 Summary
Robust interferometer
~85% Science Mode duty cycle
Good sensitivity
Stable horizon:
8.5-9.0 Mpc (1.4-1.4 Ns-Ns) - averaged
42-44 Mpc (10-10 BH-BH) - averaged
fluctuating with input mirror etalon effect
Low glitch rate: factor 10 lower than VSR1
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Exploring Big Bang phases
Γ dominant process rate,
H Universe expansion rate,
T decoupling temperature
(Γ/H)Neutrino ~ ( GF2T3/MPl)3
TNeutrino ~ 1 MeV
MPl Planck mass
GF Fermi constant
(Γ/H)Graviton ~ ( T/MPl)3
TGraviton ~ MPl
.
M. Maggiore Physics Reports 331 (2000) 283
Detection
• Need (at least) two detectors to check for statistical correlations
g
(
f
)

(
f
)
S
N
R

T
d
f

2
2
 fSf
()
Sf
()
1
2
0
6
n
,
1
G
W
n
,
2
Detecting the signal gw
S.g.w. spectral density
of the G.W. strain h
c critical density of
Universe
•
•
•
•
GW G.W. density
Ho Hubble constant
•
f frequency
3H 02
c 
8 G
• Sensitivity improves as the square root of the observation
time T1/2
• Better performances when
– detectors near each
other compared to 
– detectors aligned
Isotropic search: results
• Data collected during S5 run (one year integrated
data of LIGO interferometers)
• Point estimate of Y: no evidence of detection
integrating over 40-170 Hz (99% of sensitivity)

6


6
.
9

1
0
9
5
%
C
.
L
.
0
SGWB: beating the BBN limit!
BBN   GW ( f )df 1.110 (N  3)
5
Nv effective number of neutrino species at the time of BBN
o  6.9 10
6


71
Several gamma-ray pulsars are being found by the Fermi LAT
(both normal and millisecond).
Some potentially interesting objects:
Name
f [Hz]
fdot [Hz/s]
tau [kyr]
J1418-6058
18.09
-2.69e-11
10.3
J1459-60
19.38
-2.40e-12
64.0
J1813-1246
41.60
-7.61e-12
43.3
J1826-1256
18.14
-1e-11
14.4
J1907+06
18.75
-7.68e-12
19.4
P.Rapagnani - GWDAW14 - Rome January
2010
72
•
Some GRB-GWB models
short-duration GRBs
• coalescing compact binaries
• e.g. neutron star—neutron star mergers
• possible scenario: circularly polarized
gravitational waves
search method
independent of model
GRB
h  1  cos  ; hx  cos 
2
where θ is the angle wrt symmetry axis
• measured redshifts are smaller
Earth
GWB
 more favorable for detection of
gravitational waves
•
long-duration GRBs
• core-collapse supernovae
• possible scenario: linearly polarized
gravitational waves
GWB
GRB
h  sin 
2
 not very favorable for detection of
gravitational waves
Earth
P.Rapagnani - GWDAW14 - Rome January
2010
73
Joint LIGO/Virgo Search for GRBs
The analysis method
- Analysis based mainly on the use of X-Pipeline software (S. Chatterji et al. – INFN
fellow Roma 1)
- X-Pipeline coherently sums and squares the Fourier
series of whitened data of the N-detectors combined in a suitable way to produce
time-frequency maps of the energy of the variables E+, E×, Enull .
Results of the GRB – GW analysis
•
212 GRBs detected during S5/VSR1
– 137 in double coincidence, i.e. for any two
of LIGO Hanford (H1, H2), LIGO Livingston (L1), Virgo (V)
•
No detections! We place lower limits on distance assuming EGW = 0.01 M c2
– Typical distance limit @ 150 Hz ranging between 10 - 20 Mpc
– For GRB070201 along the line of sight of M31 @ 770 kpc, the emission limit are hrss90% = 6.38 x 10-22
Hz-1/2 @ 150 Hz and hrss90% = 27.8 x 10-22 Hz-1/2 @ 1 kHz
P.Rapagnani - GWDAW14 - Rome January
2010
74
Searches for gravitational waves from known pulsars
Vela Pulsar
Crab Pulsar
 Search for gravitational waves from 116 known millisecond and
young pulsars
 Ephemerides were obtained for all pulsars using radio and X-ray
observations
 Best upper limit on GW amplitude is 2.3 ×10 −26 for J1603−7202
 Best limit on pulsar ellipticity is 7.0× 10 −8 for J2124−3358
 New limit from Crab pulsar now 7 times below the spin-down limit.
 Limit for VELA ( VSR1 data) 2 - 3 ×10−23
P.Rapagnani - GWDAW14 - Rome January
2010
calib. lines
Dots show pulsar spindown
limits
Vela
Crab
magnetic + control
noise (PRCL,
Angular,…)
1 year
integration
sensitivities
magnetic (turbo-pumps +
cooling fans) + ?
J1813-1749
J1952+3252
J0205+6449
J1833-1034
With the current Virgo+ sensitivity the spindown limit will be surely beaten for:
J0835+4510 (Vela): 22.38 Hz (before the break in January)
J0534+2200 (Crab): 59.56 Hz (~1 yr of data needed to beat LIGO current limit)
Likely it will be beaten for:
P.Rapagnani - GWDAW14 - Rome January
2010
J1813-1749: 44.74 Hz (in a few months if the noise bump is removed!)
76
•
Burst search results: Upper limits
Combined upper limits for the entire S5/VSR1 in the frequency range 50-6000
rate limit: 2 events/year
Comparison with IGEC:
1.5 events per year but with
two orders
strain sensitivity.
P.Rapagnani
- GWDAW14lower
- Rome January
2010
Phys.Rev.Lett.103:031102,2009.
-19
10
h/ΓHz
2008 -2008-2012
2012 Network
Network
LIGO+
SFERA
-20
10
Pulsars
BH-BH Merger
Oscillations
@ 100 Mpc
h , 1 year integration
max
(Quantum Limit)
DUAL Demonstrator
(200 hbar, starting 2011)
-21
10
QNM from BH Collisions,
100 - 10 Msun, 150 Mpc
Virgo+
BH-BH Inspiral, 100 Mpc
Core Collapse
@ 10 Mpc
-22
10
QNM from BH Collisions,
1000 - 100 Msun, z=1
NS-NS Merger
Oscillations
@ 100 Mpc
BH-BH Inspiral,
z = 0.4
-6
NS, =10 , 10 kpc
-23
10
GEO HF
NS-NS Inspiral, 300 Mpc
starting 2009/2010
-24
10
10
Interferometric
NS-NS
Network
Event Rate (per year) 0.025-10
Range (Mpc)
114
100
1000
NS-BH
BH-BH
SNe
10-3-15
230
3 10-2-90
584
1
10
Hz
4
10
FROM DISCOVERY TO ASTRONOMY
2nd generation detectors:
Advanced Virgo, Advanced LIGO
Enhanced LIGO/Virgo+
2009
GOAL:
sensitivity 10x better 
look 10x further 
Detection rate 1000x larger
Virgo/LIGO
108 ly
NS-NS detectable as far as 300 Mpc
BH-BH detectable at cosmological distances
10s to 100s of events/year expected!
Adv. Virgo/Adv. LIGO
2014
Credit: R.Powell, B.Berger
Intermediate step:
Virgo+, GEO HF, Enhanced LIGO
Interferometric Detectors Sensitivity Steps:
Initial configuration (2001-2008)
•Infrastructure established
•Design Sensitiviy Reached
•Data Analysis paradigms
developed
•Many new upper limits,
important non-detections
Enhanced LIGO/Virgo+
Virgo/LIGO
108 ly
Enhanced Detectors: Now
•Sensitivity improvement by a
factor 2-3 using some of the
Advanced Detectors
technologies
•Detection still unlikely, but
surprises possible.
Advanced Detectors (2011-2015)
A factor of ~10 improvement in linear
strain sensitivity over the initial
instruments (h of ~3x10-23 in a
100 Hz bw): brings ~103 more
candidates into reach
Adv. Virgo/Adv. LIGO/LCGT
=> 10’s–100’s signals/ year
Credit: R.Powell, B.Berger
Improved Network allows to
detect position and polarization
of sources
P.Rapagnani - GWDAW14 - Rome January
2010
82
LCGT:Long Cryogenic Gravitational Telescope
3km Fabry-Perot ITF with power recycling and broadband
RSE.
Main mirrors made of sapphire are cooled at 20K.
It is built at underground site in Kamioka Mine.
Two independent interferometers are installed.
The main target is the coalescence of Binary Neutron Starｓ at
180Mpc.
150 M$
TAUP 2007 Sendai Japan
2007/09/12
CLIO: 100 m
Cryogenic
Prototype for
P.Rapagnani - GWDAW14 - Rome January
2010
LCGT
TAUP 2007 Sendai
Japan 2007/09/12
CLIO Cooling Link
AIGO: an Australian Gravitational Wave Detector
Could be AdvLIGO third interferometer?
From the AIGO project site:
(http://www.aigo.org.au/aigores.php)
“The west coast of Australia is the
best location for the southern
hemisphere detector given the
current locations of the northern
ones.
Advantages come from the fact that this
location is roughly opposite the northern
detectors, and their relative alignment is
almost optimum. Thus all the detectors
see the same gravitational wave signals
with roughly the same strength.
The AIGO site was contributed by the Western
Australian Government. It was carefully chosen
for the following reasons: easy access from the
city, flatness, isolation and its pure silica sand
which is ideal for seismic wave attenuation.
Located in the Wallingup Plain: State Forrest
65, west of Gingin, Western Australia, the site
was granted in 1998. It has been under
development since 2000, with an 80m armP.Rapagnani - GWDAW14 - Rome January
length interferometer.”
2010
The performance of the Network
would improve significantly
84
Gravitational
wave
Detectors
Underground
Spacecrafts
3 pairs of “free falling” test
masses
( 3 10-15 ms-2 Hz-1/2 @ 0.1 mHz)
3 “test-mass follower”
shielding spacecraft
Test
Masses
2 semi-independent 5 106 km
Michelson Interferometers
with Laser Transponders
Telescopes
( 40 pm Hz-1/2)
5 106 km
Goal: GW at
0.1 mHz – 0.1 Hz
Sensitivity
4 10-21 Hz-1/2 @ 1 mHz
Newtonian Gravitational Noise
BARS
SPHERES
/ VIRGO
GW OBJECTIVES
FIRST DETECTION
test Einstein prediction
G
8G
T
4
c
ASTRONOMY & ASTROPHYSICS
look beyond the visible
understand BH, NS and supernovae
understand GRB
COSMOLOGY
the Planck time:
look as back in time as theorist can conceive
There are more things in the heaven
and in earth, Horatio, than are dreamt
of in your philosophy
[Hamlet I.5]