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LIGO-G040443-00-W Gregory Mendell LIGO Hanford Observatory Gravitational Waves From Neutron & Strange Quark Stars http://www.ligo.caltech.edu Supported by the National Science Foundation

Gregory Mendell LIGO Hanford Observatory

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Gravitational Waves From Neutron & Strange Quark Stars. Gregory Mendell LIGO Hanford Observatory. Supported by the National Science Foundation. http://www.ligo.caltech.edu. The Neutron Star Idea. SN 1987A. - PowerPoint PPT Presentation

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Page 1: Gregory Mendell LIGO Hanford Observatory

LIGO-G040443-00-W

Gregory Mendell LIGO Hanford Observatory

Gravitational Waves From Neutron & Strange Quark Stars

http://www.ligo.caltech.eduSupported by the National Science Foundation

Page 2: Gregory Mendell LIGO Hanford Observatory

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The Neutron Star Idea•Chandrasekhar 1931: white dwarf stars will collapse if M > 1.4 solar masses. Then what?

•Chadwick 1932: discovers the neutron.

•Landau 1932: suggests stars have neutron cores.

•Oppenheimer & Volkoff 1939: work out NS models.

•Baade & Zwicky 1934: suggest SN form NS.

http://www.aao.gov.au/images/captions/aat050.html

Anglo-Australian Observatory, photograph by David Malin.

SN 1987A

(http://www.jb.man.ac.uk/

~pulsar/tutorial/tut/tut.html; Jodrell Bank

Tutorial)

Page 3: Gregory Mendell LIGO Hanford Observatory

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Discovery of Pulsars• Bell notes “scruff” on chart in 1967.

• Close up reveals the first pulsar (pulsating radio source) with P = 1.337 s.

• Rises & sets with the stars: source is extraterrestrial.

• LGM?

• More pulsars discovered indicating pulsars are natural phenomena.

• Hewish, wins 1974 Nobel Prize.

www.jb.man.ac.uk/~pulsar/tutorial/tut/node3.html#SECTION00012000000000000000 A. G. Lyne and F. G. Smith. Pulsar Astronomy. Cambridge University Press, 1990.

Page 4: Gregory Mendell LIGO Hanford Observatory

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Pulsars = Neutron Stars•From the Sung-shih (Chinese Astronomical Treatise): "On the 1st year of the Chi-ho reign period, 5th month, chi-chou (day) [1054 AD], a guest star appeared…south-east of Tian-kuan [Aldebaran].(http://super.colorado.edu/~astr1020/sung.html)

•Pacini 1967: neutron stars power the crab nebula

• Gold 1968: pulsars are rotating neutron stars.

•orbital motion

•oscillation

•rotation

http://antwrp.gsfc.nasa.gov/apod/ap991122.html

Crab Nebula: FORS Team, 8.2-meter VLT, ESO

Page 5: Gregory Mendell LIGO Hanford Observatory

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Pulsars Seen and Heard

Play Me

(Vela Pulsar)

(Crab Pulsar)

http://www.noao.edu/image_gallery/html/im0565.html

Crab Pulsar: N.A.Sharp/NOAO/AURA/NSF

http://www.jb.man.ac.u

k/~pulsar/Education/Sounds/

sounds.html

Jodrell Bank Observatory,

Dept. of Physics & Astronomy,

The University of Manchester

Page 6: Gregory Mendell LIGO Hanford Observatory

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Why Neutron Stars?

Masses ~ 1.4 Solar Masses

• Fastest pulsar spins 642 times per seconds; R < 74 km• Thermal observations and theory suggest R ~ 5-15 km

S. E. Thorsett and D. Chanrabarty, astro-ph/9803260

www.physik.uni-muenchen.de/sektion/suessmann/astro/cool/

Page 7: Gregory Mendell LIGO Hanford Observatory

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The back of the envelope please…

Mass neutron 1.67 × 10-24 g------------------------ = --------------------Volume neutron 4/3 (10-13 cm) 3

= 4.0 × 1014 g/cm 3 (billion tons/teaspoon)

1.4 Solar Masses 1.4(1.99 × 1033 g)------------------------ = --------------------10 km Sphere 4/3(106 cm) 3

Average density = 6.7 × 1014 g/cm 3

… but parts of you are as dense as a neutron star.

Don’t take this the wrong way…

p + e n +e (inverse beta and beta decay)p + e = n (beta equilibrium)np = ne (charge neutrality)

Seen: SN 1987A! Nuclear density: 95% n, 5% p & e

Page 8: Gregory Mendell LIGO Hanford Observatory

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Cosmic lighthouses with terra-gauss magnetic fields !

D. Page http://www.astroscu.unam.mx/neutrones/home.html

http://online.itp.ucsb.edu/online/neustars00rmode/kaspi/oh/05.html; Vicky Kaspi McGill University, Montreal Canada

More on PulsarsKnown: 1000+

Unknown: up to 100,000 in the

Milkyway.

Respun to 642 Hz!In theory up to 2 kHz. http://astrosun2.astro.cornell.edu/academics/courses/

astro201/pulsar_graph.htm

Page 9: Gregory Mendell LIGO Hanford Observatory

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What else is seen?

http://www.astroscu.unam.mx/neutrones/home.html

http://antwrp.gsfc.nasa.gov/apod/

ap980527.html

Robert Mallozzi (UAH, MSFC)

http://www.jb.man.ac.uk/~pulsar/tutorial/tut/tut.html

HMXBs

LMXBs

Magnetars

Pulsar Glitches

Page 10: Gregory Mendell LIGO Hanford Observatory

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Now it gets interesting…

D. Page http://www.astroscu.unam.mx/n

eutrones/home.html

•Fermi Temp = 1012 K

•NS born at 1011 K, cools below 109 K within a year; BCS superfluids form.

•Cools to 106 K over 107 K yrs.

•NS are compact “cold” degenerate objects; GR & QM required to understand.

Page 11: Gregory Mendell LIGO Hanford Observatory

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…and strange…

http://chandra.harvard.edu/resources/illustrations/neutronstars_4.html

NASA/CXC/SAO

Page 12: Gregory Mendell LIGO Hanford Observatory

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… and hyper-

stranger still!

Page 13: Gregory Mendell LIGO Hanford Observatory

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Strange Stars in the News

Page 14: Gregory Mendell LIGO Hanford Observatory

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Recent Papers

Page 15: Gregory Mendell LIGO Hanford Observatory

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Some Of The Big Questions?• What is the NS/SQS max. mass; min radius? (1.4-3.5 M? R = ?)

• How fast can NS/SQS spin (up to 2 kHz?) and what controls their spin cycles?

•What are the final states of matter before collapse to BH, i.e., what’s inside these stars, really?

• Are quark nuggets hitting the Earth? (Ice-9 Scenerios?)

J. M. Lattimer & M. Prakash, astro-ph/0405262

Page 16: Gregory Mendell LIGO Hanford Observatory

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Laser Interferometer Gravitational-wave Observatories

Figures: K. S. Thorne gr-qc/9704042; D. Sigg LIGO-P980007-00-D

LIGO is a lab looking for direct detection of GW’s.

LIGO is an observatory, “listening” for GW’s cosmic spacetime vibrations.

Gravitational-wave Strain: LLh /

Page 17: Gregory Mendell LIGO Hanford Observatory

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Continuous Periodic Gravitational-Wave Sources

Wobbling star

“Mountain” on star

Accreting star

Oscillating star

A. Vecchio on behalf of the LIGO Scientific Collaboration : GR17 – 22nd July, 2004

I

II 21

Triaxial Ellipsoid:Ellipticity

LMXB:e.g., Sco X-1:balance GW torque with accretion torque.

Free PrecessionWobble Angle

Mode with Saturation Amplitude A

Page 18: Gregory Mendell LIGO Hanford Observatory

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• Triaxial ellipsoid: h ~ (G/c4) MR24frot 2/r ~ 10–26 (for ellipticity ~

10–6, frot = 200 Hz, M = 1.4 M, R = 106 cm, r = 1 kpc = 3 1021 cm)

• Precession: h ~ (G/c4) sin (2) MR2frot2/r ~ 10-27 (for ellipticity ~

10-6 ; wobble angle = /4, etc…)

• LMXB Sco-X1: h ~ 10-26 (balance GW torque with accretion torque)

• R-modes: h ~ (G/c4) MA2R2 (16/9) frot

2/r ~ 10–26 ( for saturation amplitude A ~ 10–3, etc…)

• Pulsar Glitch h ~ (G/c4) MA2R2frot

2/r ~ 10 –32 ( for glitch amplitude A ~ 10–6, etc…)

.22149

.2

24

)(10~;)(~

~;)/)(/(/

asymGWasym fMRerghMVQ

MRQrQcGLLh

Approximate forms of the Quadrupole Formula

The back of the envelope please…

Page 19: Gregory Mendell LIGO Hanford Observatory

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LSC Period/CW Search GroupSearch Techniques

• ~ 30+ members of the LIGO Science Collaboration.

• Has developed Coherent & Incoherent Search Methods

• Known, Targeted,and All Sky Searches are underway.

4/17

2/12325

7

2/12326

int

0

22int

101800

10102

10

10103

~/

|)(|2

obscoh

n

incohc

obs

n

cohc

obsn

T

T

s

T

s

Hz

Sh

T

s

Hz

Sh

TShSNR

dtthhcoh

Page 20: Gregory Mendell LIGO Hanford Observatory

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Figure: P. Brady ITP seminar summer 2000

Sensitivity Curves

The r-mode saturation amplitude was thought to be much larger in 2000

Page 21: Gregory Mendell LIGO Hanford Observatory

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Coherent Power vs. Tobs

Page 22: Gregory Mendell LIGO Hanford Observatory

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Incoherent Power vs. Tobs

Page 23: Gregory Mendell LIGO Hanford Observatory

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Phase Modulation

0

10 )ˆ

)((

)!1(s

ss

nc

trt

s

f

Page 24: Gregory Mendell LIGO Hanford Observatory

LIGO-G040443-00-W

Frequency Modulation

• The frequency is modulated by the intrinsic frequency evolution of the source and by the doppler shifts due to the Earth’s motion

• The Doppler shifts are important for observation times

10 )ˆ

)((

!)ˆ

)(1()(

s

ss

nc

trt

s

ffn

c

tvtf

.sec300

105.50

3

f

HzT

Schutz & Papa gr-qc/9905018; Williams and Schutz gr-qc/9912029; Berukoff and Papa LAL Documentation

Page 25: Gregory Mendell LIGO Hanford Observatory

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Figure: D. Sigg LIGO-P980007-00-D

]2cos2sincos2sin2cos)cos1(5.0[

]2sin2sincos2cos2cos)cos1(5.0[)(

);()();()(ˆ)(ˆˆ)(ˆ)(

2

2

h

hth

tFthtFthyMMhyxMMhxth tTTtTT

Amplitude Modulation

Page 26: Gregory Mendell LIGO Hanford Observatory

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Maximum Likelihood

0,0,0cos

,0

),,cos,(

2

12

)(

...2

1

2

1

2

1)|(

2

0

22

0

2

00

222

22

2

)(

3

2

)(

2

2

)(

1

23

233

22

222

21

211

h

hfh

hhhxhx

eeehxP

j

j j

jj

j j

jj

j j

jj

hxhxhx

Likelihood of getting data x for model h for Gaussian Noise:

Chi-squared

Minimize Chi-squared = Maximize the Likelihood

Page 27: Gregory Mendell LIGO Hanford Observatory

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Coherent Match Filtering

1

0

1

0

)0(M N

j

ijb

jbeFxX

1

0

/21 N

k

NijkSFTkj eX

Nx

1

0 )(2

)2cos1(2sin)0( 0

M

k b

bb

k

SFTki

b k

i

S

XeFX

Jaranowski, Krolak, & Schutz gr-qc/9804014; Schutz & Papa gr-qc/9905018; Williams and Schutz gr-qc/9912029; Berukoff and Papa

LAL Documentation

222

*2222 24

FFFF

XXeFFXFXF

MF

Page 28: Gregory Mendell LIGO Hanford Observatory

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The StackSlide Search• An incoherent search method that stacks

and slides power to search for periodic sources. (P. Brady & T. Creighton Phys. Rev. D61 (2000) 082001; gr-qc/9812014.)

• The periodic search is computationally bound. A hierarchical approach that combines coherent & incoherent methods is needed to optimize sensitivity.

• Sources like LXMBs with short coherence times (~ 2 weeks) require incoherent methods.

• Mendell and Landry are developing the StackSlide Search for the CW group. (The group also uses Hough Transforms and Power Flux, for incoherent searches.)

Bins with frequency domain data, e.g., from SFTs or F-statistic.

A. Stack the power.

B. Slide to correct for spindown/doppler shifts.

C. Sum and search for significant peaks.

Page 29: Gregory Mendell LIGO Hanford Observatory

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Validation: Fake Pulsar vs Fake Instrument Line

Page 30: Gregory Mendell LIGO Hanford Observatory

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Sky Distribution of PowerFake Pulsar and Fake Noise:

Page 31: Gregory Mendell LIGO Hanford Observatory

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Sky Distribution of PowerFake Instrument Line and Noise

Page 32: Gregory Mendell LIGO Hanford Observatory

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Sky Distribution of PowerFake Noise Only:

Page 33: Gregory Mendell LIGO Hanford Observatory

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Find peaks above threshold

Slide Stacks and SUM

Veto peak based on width

Select template

Veto on Coincidence

Veto Instrument Lines

Veto SNR does not grow as T

Yes

SFTs are generated only once

Input a band from SFTs

Raw Data

Compute PSDs from SFTs

Normalize PSDs

Template placement

Output event

StackSlide Pipeline

Normalize SFTs

Compute F-statistic for each point in the course grid

Template placement

Parameter space metric placement

Uniform placement

No

Set UL from LE

Detection candidate

MonteCarlo

LineRemoval

VetoSFTs

Page 34: Gregory Mendell LIGO Hanford Observatory

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Statistics

dzedzzP

rdrdzyxrz

rdredrrP

ryrx

dxdyeedxdyyxP

yxniyxn

nFFTNormalizedn

z

r

yx

2/

222

2/

2/2/

222

2

1)(

2

1

)(

sincos2

1

2

1),(

~

)(~

2

22

Gaussian Noise

Rayleigh Dist.

2 variable, with 2 degrees freedom

2 Distribution

Page 35: Gregory Mendell LIGO Hanford Observatory

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Statistics: False Alarm Rate; False Dismissal Rate and UL from LE

Page 36: Gregory Mendell LIGO Hanford Observatory

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-- GEO-- L 2km-- H 4km-- L 4km

<h 0

>

S1 sensitivities

PSR J1939+2134P = 0.00155781 sfGW = 1283.86 Hz

dP/dt = -1.0511 10-19 s/sD = 3.6 kpc

obs

h0 T

)f(S4.11h

Result: S1 Coherent Search

• ho<1.4x10-22 constrains ellipticity < 2.7 x 10-4 (M=1.4 Msun, r=10 km, R=3.6 kpc)

B Allen and G Woan on behalf of the LIGO Scientific Collaboration : Amaldi 9 July, 2003.