G080441-00-D LIGO Laser Interferometer Gravitational-wave Observatory ETH Zürich, October 2008 Daniel Sigg, LIGO Hanford Observatory

G080441-00-D

LIGOLaser Interferometer

Gravitational-wave Observatory

ETH Zürich, October 2008 Daniel Sigg, LIGO Hanford Observatory

ETH Zürich 2G080441-00-D

LIGO Scientific CollaborationAustralian Consortiumfor InterferometricGravitational AstronomyThe Univ. of AdelaideAndrews UniversityThe Australian National Univ.The University of BirminghamCalifornia Inst. of TechnologyCardiff UniversityCarleton CollegeCharles Sturt Univ.Columbia UniversityEmbry Riddle Aeronautical Univ.Eötvös Loránd UniversityUniversity of FloridaGerman/British Collaboration forthe Detection of Gravitational WavesUniversity of GlasgowGoddard Space Flight CenterLeibniz Universität HannoverHobart & William Smith CollegesInst. of Applied Physics of the Russian Academy of SciencesPolish Academy of SciencesIndia Inter-University Centrefor Astronomy and AstrophysicsLouisiana State UniversityLouisiana Tech UniversityLoyola University New OrleansUniversity of MarylandMax Planck Institute for Gravitational Physics

University of MichiganUniversity of MinnesotaThe University of MississippiMassachusetts Inst. of TechnologyMonash UniversityMontana State UniversityMoscow State UniversityNational Astronomical Observatory of JapanNorthwestern UniversityUniversity of OregonPennsylvania State UniversityRochester Inst. of TechnologyRutherford Appleton LabUniversity of RochesterSan Jose State UniversityUniv. of Sannio at Benevento, and Univ. of SalernoUniversity of SheffieldUniversity of SouthamptonSoutheastern Louisiana Univ.Southern Univ. and A&M CollegeStanford UniversityUniversity of StrathclydeSyracuse UniversityUniv. of Texas at AustinUniv. of Texas at BrownsvilleTrinity UniversityUniversitat de les Illes BalearsUniv. of Massachusetts AmherstUniversity of Western AustraliaUniv. of Wisconsin-MilwaukeeWashington State UniversityUniversity of Washington


Scientific Goals of LIGO

Discover the gravitational waves predicted by General Relativity

Use gravitational waves to pioneer a new window on the universe


What is the observable effect?

Amplitude parameterized by (tiny) dimensionless strain h:

( )( )

L th t

L

Example:

Ring of test masses

responding to wave

propagating along z


LIGO Livingston Observatory

LIGO Hanford Observatory

Arial View of the LIGO Sites


Power-Recycled Michelson

Interferometer with Fabry-Perot

Arm Cavities


Main Features

4 km vacuum envelope10-9 torr

Seismic isolation stack Suspended masses 10W Nd:YAG laser, 1064 nm Suspended mode cleaner Feedback controls for length

and alignment Physical environment

monitor


S4 Sensitivity




Time Line

NowInauguration First Lock Full Lock all IFO

10-17 10-18 10-20 10-21 10-224K strain noise at 150 Hz [Hz-1/2]

3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4

1999 2000 2001 2002 2003 2004 2005 2006

1 2 3 4

2007

1 2 3 4

2008

1 2 3 4

2009

1 2 3 4

2010

1 2 3 4

2011

Design Sensitivity

3x10-23

First Science Data

S1 S4Science

S2

Runs

S3 S5 S6

1 year ofCoincidenceData

Enhanced LIGO

Advanced LIGO

Installation and Commissioning


The 5th Science Run


0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 100 200 300 400 500 600 700

Calendar Time(days)

Ac

cu

mu

late

d T

ime

(h

ou

rs)

Accumulated triple-coincidence

1 yr = 8765.8 hrs

Jan 1, 2006

Apr 1,

2006

Jul 1, 2006

Oct 1,

2006

Jan 1, 2007

Apr

1, 2007

Jul 1, 2007

Oct 1,

2007

48%

67%

Duty factor is for operating all THREE interferometers in SCIENCE MODE


Signal duration and template

Short duration Long duration

un-

modeled Burst search Stochastic search

matched filter

Inspiral search CW search

Credit: NASA/CXC/ASU/J. Hester et al.


GRB 070201

Short, hard gamma-ray burst A leading model for short GRBs:

binary merger involving a neutron star

Position (from IPN) consistent with being in M31 (Andromeda)

LIGO H1 and H2 were operating

Result from LIGO data analysis:No plausible GW signal found;therefore very unlikely to befrom a binary merger in M31


Crab Pulsar

Result from first 9 months of S5:Consistent with Gaussian noise

Upper limits on GW strain amplitude h0

Single-template, uniform prior: 3.4×10–25

Single-template, restricted prior: 2.7×10–25

Multi-template, uniform prior: 1.7×10–24

Multi-template, restricted prior: 1.3×10–24

Implies that GW emission accountsfor ≤ 4% of totalspin-down power

Cha

ndra

imag

e

Mod

el


Search for a Stochastic GW Background

Cross-correlated LIGO data streams to estimate energy density in isotropic stochastic GW, assuming a power law

Partial, preliminary result from S5 is comparable to constraint from Big Bang nucleosynthesis

John

T.

Whe

lan

for

the

LSC

, A

AS

Mee

ting,

Jan

200

8


Known pulsars

Timing by Jodrell Bank Pulsar Group


Binary Neutron Star Sources

Single detector, SNR=8, averagedMilky Way ~ 1.6 x L10

No detection so far


Network Analysis

300 m

600 m3 km

4 km2 km

4 km

ALLEGRO

EXPLORER AURIGA

NAUTILUS

CLIO100 m

Mario Schenberg

Bar / SphereInterferometer


Enhanced LIGO


Key Technologies

In-vacuum output mode cleaner Currently installed and being commissioned New advanced LIGO seismic isolation

DC readout scheme Crucial for advanced LIGO

30W laser (LZH/Hannover) First stage of advanced LIGO laser Will require bigger thermal compensation system

Input optics New high power Faraday isolator & Pockels cells

New earthquake stops (fused silica tipped)


Advanced LIGO

Funding approved at the beginning of this year!

An order of magnitude improvement in sensitivity 3 orders of magnitude

improvement in rate!

100 million l-y


Key Technologies

Active seismic isolation system Hydraulic pre-isolator 2 stage in-vacuum isolation system

Multiple suspension stages 30 kg test masses

Active thermal compensation

180 W laser source High power input optics

Signal recycling added In-vacuum detection benches


Summary

First relevant science results are published!And more to come…

All LIGO interferometers are at design sensitivity For sources like binary neutron star and black hole

coalescence we can see well into the Virgo cluster The first big science run is done with 1 year of

coincidence data Enhanced LIGO commissioning is in progress Advanced LIGO is funded

We should be detecting gravitational waves regularly within the next 10 years!

Documents

G080441-00-D LIGO Laser Interferometer Gravitational-wave Observatory ETH Zürich, October 2008 Daniel Sigg, LIGO Hanford Observatory