Cryogenic resonant mass GW detectors: what they do now how they may do even more in the future Massimo Cerdonio INFN Section and Department of Physics Padova

AURIGA www.auriga.lnl.infn.it

Direttivo 27/05/05

“bar” gw detectors detect space-time “strain”



L/L ~ h

gw

M = 2.3 t L = 3m

sensitivity

the spectral noise power

S hh (f)

of the equivalent GW amplitude h(t) at the detector input

bandwidth

potentially infinite…

antenna pattern

sen

2

 cos2 

VIRGO --------------------

the Standard Quantum Limit

(for impulsive signals)

detect one quantum in a 2.3 tons oscillator !!!

Need:

• wide detection bandwidth  f~100 Hz, large Q/T ~ 10

8

T~ 0.1 K, Q ~ 10

7

• a quantum limited amplifier (SQUID or optical) K

-1

where are we ?

 f~100 Hz Q ~ 5 10

6

AURIGA @ 4.5 K

 E ~ 500 quanta

AURIGA @ 0.1 K

 E ~ 10 quanta

h

SQL

~ 3 10

-21

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: AURIGA+EXPLORER+NAUTILUS+VIRGO • 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]

INFN

• Genova • LNF • Roma 1 • Roma 2 • L’Aquila

EXPLORER (CERN) NAUTILUS (LNF)

both detectors on the air by decades >>> see results in:

www.roma1.infn.it/rog

EXPLORER

Data Taking in 2004

NAUTILUS

4.9 ·10 -19 Duty Cycle 2004 = 75% 2004-2005 = 85% 2.8·10 -19 Duty Cycle 2004 = 90% 2004-2005 = 93%

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

Al5056

EXPLORER and NAUTILUS in coincidence: upper limits on GW from BATSE+BeppoSAX



-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 < 2.5 10

-19

(improves on previous limits given by AURIGA with a cumulative “on-off” analysis)

Bar Network

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 h ~ 2 10 -18  E ~ 0.02 M sun converted into gw at the Galactic Center

“spheres”

• omnidirectionality: decode the excitation of the 5 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

Bar with optomechanical transducer

certezze e prospettive

certezze

gw exist:

binary 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 > 1 kHz band

physics:

gravity overwhelms fundamental interactions

neutron stars: black-holes:

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) merger, vibrations (study extreme gravity)

gw the only direct probe of dynamics

f ~ 10 Hz - 1kHz: detect phase coherent “chirps” lasting ~ 10

3

s unfolding on the whole band >>> “interferometers” the best f > 1kHz: extract short “bursts” from noise to detect fine time structure details >>> “bars” the best (in “tune”…)

f > 1 kHz need:

• stationary “gaussian” • S

hh

(f) ~ 10

-23

Hz

-1/2

(few spuria/day) wideband detector AURIGA >>> 100Hz band, 99%duty cycle, few spuria/day over f ~ 1-5 kHz DUAL the 5 kHz wideband detector

AURIGA Sezioni INFN: Fe, Fi, LNL, Pd-Tn

3-modes operation (2 mech+1 el) SQUID close to quantum limit

1x10 -19 AURIGA T=4.5K

one-sided S hh

S

hh

sensitivity

- noise prediction - mechanical thermal - LC thermal - SQUID back action - SQUID additive 1x10 -20 1x10 -21 1x10 -22 800 850 900 Frequency [Hz] 950 resolve arrival times to 10 ms for SNR~5 to 1 ms for SNR~10 Noise figure agrees with predictions and will scale with temperature 1000

picchi spuri in banda ?!?!?

effetti

non lineari

riportano in banda la potenza di rumore ambientale a 5-40 Hz e contaminano con 1000 ev/ora nella meccanica che (per altro come LIGO…) vacanze ad alto SNR la lista eventi eccitabili a soglia: effetti giorno/notte, week-end,

(un problema generale…?)

isolare a bassa freq per andare sotto soglia

saldatura ad arco delle “ali” per appoggiare sulle molle ad aria compressa freq taglio 1 Hz (sui piloni)

nuove sospensioni bassa freq 19/05/05 “sui piloni” senza interruzione del run criogenico

“prima della cura” “dopo la cura”

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) SNR

date

red: exp blue: sim

the Dec 27 2004 giant flare from SGR 1806-20 95%confidence upper limits:  gw theory (magnetar “big one” ):  gw < 5 10

-6

M

O c 2

(best…) ~ 5 10

-6

M

O c 2

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”

f~1kHz h~10

-19

d~100 kpc (Galassia)

2-3 barre “AURIGA 0.1 K” + VIRGO SNR ~ 10 falsi allarmi << 1/cy neutrino “supernova watch” SNEWS ~ stesso range e falsi allarmi

le sensibilita’ nella prospettiva 2006 - 2012

DUAL 2 nested resonant masses GW signals add back action noises subtract

Measure the differential deformation

between

the lowest quadrupolar modes

Sensitive in a kHz-wide freq band !!!

feasibility study funded by:

DUAL R&D, ILIAS and EGO

prospettive 2 segnale “garantito” a neutron stars binary of 1.4 + 1.4 M • determine chirp mass M

SUN

coalesces at 50 Mpc (~1 ev/y @ 50-100 Mpc: “assured” signal) advanced VIRGO + “sphere” see the last ~1000 s of chirp: • predict to ~ 1ms the time when merging starts • predict the frequency f~1 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 QuickTime™ and a Sorenson Video decompressor are needed to see this picture.

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 < 1 kHz, di riferimento per gli interferometri (in fase di approvazione LIGO-2 “promette” a NSF tra 10 e 500 Hz) l’aria e’ cambiata: il ruolo competitivo/complementare 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 >>> edifici “dedicati” e/o underground • incoraggiare teorici e analisti dati “fuori dal coro” (RomaI e II, Parma, Padova, SISSA,……) • interesse di altre Sezioni a: l’analisi dei dati che produciamo lo sviluppo dei rivelatori attuali e futuri