DAY 5

1
DAY 5 GRAVITATIONAL ASTRONOMY
2
with bars
3
with LIGO
supernovae?
4
Chandrasekhar-Friedman-Schutz Instability in
Pulsars
5
Chandrasekhar-Friedman-Schutz Instability
Rotational mode in a rotating star
6
Chandrasekhar-Friedman-Schutz Instability
Rotational mode in a rotating star
7
r-mode and f-mode radiation
f-mode _at_ 15 Mpc
r-mode _at_ 15Mpc
8
Close Compact Inspiral and Coalescence

• And search for this template in this data

9
Compact Binary Coalescence
BH-BH (10M?) _at_ 100 Mpc
NS-BH (10M?) _at_ 200 Mpc
NS-NS _at_ 200 Mpc
10
LIGO and LISA An Overview
11
Galaxy Mergers
12
MBH mergers

• MBHs are found at the centers of most galaxies
• Most galaxies merge one or more times
• ? MBH binaries

• MBH mergers are strong sources of gravitational
  waves
• These GW are detectable by LISA out to z 10 or
  more
• Expect several events/year, or more
• (possibly many more...)

(NCG6240 Chandra Image NASA/CXC/MPE/S.Komossa et
al. )
13
(No Transcript)
14
Binary Black Hole Signal in LISA Noise
15
Close Compact Binaries

• Known (guaranteed) sources
• Close contact WD binaries

• Chirping NS-NS binaries
• ? complete 3-D survey

• Embarrassment of riches

AM Can Vn
16
The LISA White-Dwarf Binary Population
confusion
17
LISA Data Analysis
Goals

• Detect a gravitational wave source in the LISA
  data stream
• Determine the parameters of the source
• Subtract the signal for this source from the data
  stream
• Go to 1

18
THE PROBLEM
19
A Monochromatic Binary Signal seen in a
barycentric frame
20
The same signal seen in an orbiting and
precessing frame
21
The same signal seen in the presence of typical
LISA noise
hf (?10?18)
?f (?Hz)
22
How to frequency demodulate the LISA signal
Form an effective barycentric (unmodulated)
signal via sbarycentric(t) sLISA(t ? ?)
23
The same signal seen in the presence of typical
LISA noise
hf (?10?18)
?f (?Hz)
24
The result of Doppler demodulation
25
Why is the Doppler-demodulated signal so funky?
26
The Solution Total Demodulation
27
Generating a Gravitational Wave
28
Detecting a Gravitational wave
29
Relating the Fwo Frames
30
LISA Gravitational Wave Response
31
Example a monochromatic binary plus LISA
simulated noise, hi-pass filtered at 104 Hz
32

• Doppler demodulate for each sky pixel

• Click on a pixel to select it

33

• Examine the spectrum for this pixel

Output of program BINARY For a source at
theta,phi 29.724, 66.451 with frequency
3.168752934186E-03, the source parameters are
A 1.4512E-21 i 30.916704 psi 23.59202
pho 4.0948

• Filter to find h and h? for each frequency

34
The final step
Linear least squares
Why

• Template matching with infinite resolution
• Correct treatment of parameter correlations

35
Moral The LISA Data Analysis Method

• All-sky total-demodulate the signal
• Find the brightest source in the sky (? ?, ? )
• Examine the filtered spectrum (? f )
• Solve for the intrinsic parameters (i, ?, ? , ?0)
• Perform a least-squares fit

for ALL sources so far
6. Form a new time series with the sources
subtracted 7. Go to 1
and it works
36
REVIEW
37
REVIEW

• Current bar detectors will see gravitational
  waves if there is another supernova in the Galaxy
• Advanced LIGO and VIRGO will probably detect
  gravitational waves and may begin to do astronomy
  on compact binaries or pulsars
• LISA will
• Detect gravitational waves from known sources
• Survey all NS-NS binaries in the Galaxy
• Determine WD-WD statistics to inform
  common-envelope evolution studies
• See mergers of massive black holes in galactic
  nuclei and inform models of hierarchal galaxy
  formation and evolution
• Map out the field of a black hole (seeing a
  black hole)
• Test GR in the strong field regime

38
au revoir!