bar gw detectors

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Direttivo 27/05/05
AURIGA www.auriga.lnl.infn.it
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bar gw detectors detect space-time strain
?L/L hgw
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sensitivity

• the spectral noise power Shh(f) of the
  equivalent GW amplitude h(t) at the detector
  input

bandwidth potentially infinite
antenna pattern sen2??cos2?
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VIRGO --------------------
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the Standard Quantum Limit (for impulsive
signals)
detect one quantum in a 2.3 tons oscillator !!!

• Need
• wide detection bandwidth ?f100 Hz, large Q/T
  108 K-1
• T 0.1 K, Q 107
• a quantum limited amplifier (SQUID or optical)
• where are we ?
• AURIGA _at_ 4.5 K ?E 500 quanta
• AURIGA _at_ 0.1 K ?E 10 quanta

?f100 Hz Q 5 106
hSQL 3 10-21
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• what bars have done (highlights)
• acoustic detection of cosmic rays ROG
• upper limits on GW primordial background ROG
• upper limits on GW from ?-ray bursts ROG,
  AURIGA
• the first operation as a network IGEC
• and what are doing now (highlights)
• a second run of IGEC (Int. Gravitational Events
  Coll.)
• searches with a single stationary gaussian bar
  AURIGA
• searches with a local network of bars ifos
• AURIGAEXPLORERNAUTILUSVIRGO
• consider searches in a global network (within
  GWIC)
• develop a bar with optical read-out AURIGA
• develop a sphere ROG
• study feasibility of dual AURIGA

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• INFN
• Genova
• LNF
• Roma 1
• Roma 2
• LAquila

EXPLORER (CERN)
NAUTILUS (LNF)
both detectors on the air by decades gtgtgt see
results in www.roma1.infn.it/rog
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Data Taking in 2004
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NAUTILUS detected cosmics need to understand
details of the interaction with the bar
Study effects of electrons on a small bar with
DA?NE Beam Test Facilty
underground operation of resonant mass gw
detectors ?
RAP Acoustic detection of particles
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EXPLORER and NAUTILUS in coincidence upper
limits on GW from BATSEBeppoSAX ?-bursts
Astone et al, PR D71 042001 (2005)
Cumulative analysis in a 10 s time interval
around 387 GRB events gives upper limit on gw
amplitude h lt 2.5 10-19
(improves on previous limits given by AURIGA
with a cumulative on-off analysis)
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Bar Network
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Upper limit for burst GWs with random arrival
time and measured amplitude ? search threshold
PRL 85 5046 (2000) Phys. News Upd. 514 Nov. 29
(2000) - PRD 68 022001 (2003)
UPPER LIMIT on the RATE of BURST GW from the
GALACTIC CENTER DIRECTION
Current world record
DE 0.02 Msun converted into gw at the Galactic
Center
h 2 10-18
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• spheres
• omnidirectionality decode the excitation of the
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• quadrupolar modes to get uniform sky
  coverage
• find direction of propagation
• cross section larger as the volume fill-up
  factor in
• respect to bars

MiniGRAIL (Leiden-ROG) just started
operation Schenberg (Brasil) coming to
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(No Transcript)
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certezze e prospettive
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certezze
gw existbinary pulsar dynamics agrees to highest
known post-Newtonian order with
Einstein GR
the 10 Hz - 1 kHz gw band chirps of
inspiraling ns-ns and bh-bh binaries physics
dynamics of point masses in full GR
the f gt 1 kHz band physics gravity
overwhelms fundamental interactions neutron
stars hot newborn after Sn, merger after
coalescence of binaries, vibrations, rotational
instabilities, shock waves in the neutron
fluid, crust cracking (role of Equation Of
State) black-holes merger, vibrations (study
extreme gravity)
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gw the only direct probe of dynamics
f 10 Hz - 1kHz detect phase coherent
chirps lasting 103 s unfolding on the whole
band gtgtgt interferometers the best
f gt 1kHz extract short bursts from noise to
detect fine time structure details gtgtgt bars
the best (in tune)

• f gt 1 kHz need
• stationary gaussian (few spuria/day) wideband
  detector
• AURIGA gtgtgt 100Hz band, 99duty cycle, few
  spuria/day
• Shh(f) 10-23 Hz -1/2 over f 1-5 kHz
• DUAL the 5 kHz wideband detector

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AURIGA
Sezioni INFN Fe, Fi, LNL, Pd-Tn
3-modes operation (2 mech1 el) SQUID close to
quantum limit
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Shh sensitivity
one-sided Shh
resolve arrival times to 10 ms for SNR5 to 1 ms
for SNR10
Noise figure agrees with predictions and will
scale with temperature
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picchi spuri in banda ?!?!?
effetti non lineari nella meccanica che riportano
in banda la potenza di rumore ambientale a 5-40
Hz e contaminano con 1000 ev/ora (per altro come
LIGO) ad alto SNR la lista eventieccitabili a
soglia effetti giorno/notte, week-end,
vacanze(un problema generale?)
isolare a bassa freq per andare sotto soglia
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saldatura ad arco delle ali per appoggiare
sulle molle ad aria compressa freq taglio 1 Hz
(sui piloni)
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nuove sospensioni bassa freq 19/05/05 sui
piloni senza interruzione del run criogenico
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prima della cura
dopo la cura
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P.Falferi et al, 3-modes detection
Phys.Rev.Letters (in stampa) M.Bonaldi et
al,AURIGA suspensions Rev. Sci. Instr (in
stampa) A.Vinante et al, Thermal noise in a
Rev. Sci. Instr (in stampa)
red exp blue sim
SNR
date
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the Dec 27 2004 giant flare from SGR 1806-20
95confidence upper limits ?gw lt 5 10-6 MOc2
(best) theory (magnetar big one ) ?gw
5 10-6 MOc2
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prospettive 1 la prossima supernova
da 30 anni calcoli via via piu raffinati hanno
abbassato le aspettative di segnale di molti odg,
ora (Shibata PRD 2005) 3D fully GR
simulations with realistic EOS for ns matter
f1kHz h10-19 d100 kpc (Galassia)
2-3 barre AURIGA 0.1 K VIRGO SNR
10 falsi allarmi ltlt 1/cy
neutrino supernova watch SNEWS
stesso range e falsi allarmi
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le sensibilita nella prospettiva 2006 - 2012
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2 nested resonant masses
DUAL
Measure the differential deformation between the
lowest quadrupolar modes
GW signals add back action noises subtract
Sensitive in a kHz-wide freq band !!!
feasibility study funded by DUAL RD, ILIAS and
EGO
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prospettive 2 segnale garantito

• a neutron stars binary of 1.4 1.4 MSUN
  coalesces at 50 Mpc
• (1 ev/y _at_ 50-100 Mpc assured signal)
• advanced VIRGO sphere see the last 1000 s of
  chirp
• determine chirp mass M
• predict to 1ms the time when merging starts
• predict the frequency f1 kHz at which merging
  starts

DUAL using calculated waveforms (EOS dependent M.
Shibata PRL 05) detects quasiperiodic
oscillations at 3-4 kHz of 100 ms duration
with SNR 10
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LIGO ha condizionato fortemente lo sviluppo del
campo, sbilanciandolo per farlo approvare,
la NSF ha dovuto dichiarare le barre vecchia
generazione (essendo LIGO il futuro) con
riflessi internazionali (ci ha toccato
direttamente il commento di Richter- I valut.
INFN) il grosso dello sviluppo teorico e di
analisi dati e stato orientato per LIGO
nella banda lt 1 kHz, di riferimento per gli
interferometri (in fase di approvazione
LIGO-2 promette a NSF tra 10 e 500 Hz)
laria e cambiata il ruolo competitivo/complemen
tare ora e in prospettiva di barre, sfere e dual
e internazionalmente riconosciuto
D. perche l INFN ha ancora le barre ? R.
lungimiranza e indipendenza

• auspici
• rivelatori al limite quantico gtgtgt edifici
  dedicati e/o underground
• incoraggiare teorici e analisti dati fuori dal
  coro (RomaI e II,
• Parma, Padova, SISSA,)
• interesse di altre Sezioni a
• lanalisi dei dati che produciamo
• lo sviluppo dei rivelatori attuali e futuri