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Transcript
Origin and registration of gravitational waves in
space and on the Earth
G.S.Bisnovatyi-Kogan,
Space Research Institute of RAS, Moscow, Russia,
and
National Research Nuclear University “MEPhI”, Moscow,
Russia
The 2nd international conference on
particle physics and astrophysics
Moscow, October 11, 2016
Discovery of pulsars: A.Hewish, J.Bell et al., 1968, Nature, 217, 709
1973: all pulsars are single (more than 100)
more than half massive stars (predesessors of pulsars) are in binaries.
Possible explanations: pair disruption during explosion
no possibility to form a radiopulsar in pairs
1971: X-ray satellite UHURU
Discovery of X-ray pulsars in binaries.
Her X-1: X ray pulsar
Period of pulsations P(p)=1.24 sec, orbital P(orb)=1.7 days
Neutron star mass 1.4 Solar masses
Optical star mass about 2 Solar masses
This system should give birth to the binary radiopulsar
Bisnovatyi-Kogan G.S. and Komberg B.V., 1974, Astron. Zh. 51,373
Reasons:
1. After 100 million years the optical star will become a white dwarf,
mass transfer will be finished, and the system will be transparant to
radio emission.
2. X ray pulsar is accelerating its rotation due to accretion, so after
the birth of the white dwarf companion the neurton star will rotate
rapidly, P(p) about 100 msec.
Question:
Why are the binary radiopulsars not found (1973) ?
Answer (B-K, K, 1974):
Because the magnetic field of the neutron star is decreasing about 100 times
during the accretion, so binary radiopulsars are very faint objects,
2 4
Pulsar luminosity L ~ B /P
At small B luminosity L is low even at the rapid rotation
Magnetic field is screened by the infalling plasma
Physics Today
1975, 28, No.11,
pp. 46-54
Informal discussion
at Landau Theor. Inst.
Left to right:
G.S.Bisnovatyi-Kogan,
I.D.Novikov,
Academicians
V.L.Ginzburg and
Ya.B.Zeldovich, and
David Pines.
(Photo G.Baym)
The properties of the first binary pulsar coinside with our predictions:
Rapid rotation and Small magnetic field
12
The average magnetic fields of single radiopulsars is about 10 Gauss.
New class of neutron stars: recycled pulsars, more than 180 objects.
All passed the stage of accreting pulsars, accelerating the
rotation and decreasing the magnetic field.
Ordinary pulsars
Recycled pulsars
P=0.033 – 8 sec
P=1.5 – 50 msec
11
13
B= 10 - 10 Gauss
8
10
B=10 - 10 Gauss
GR Effects:
NS+NS
GR is confirmed with precision ~0.01%
MERGING of COMPACT STARS in
CLOSE BINARIES (LIGO-VIRGO)
Probability density function
that represents our
expectation that the actual
DNS binary merger rate in
the Galaxy ( bottom axis)
and the predicted initial
LIGO rate ( top axis) take on
particular values, given the
observations. The solid line
shows the total probability
density along with those
obtained for each of the three
binary systems ( dashed
lines). Inset: Total
probability density, and
corresponding 68%, 95%,
and 99% confidence limits,
shown in a linear scale.
Kalogera V et al. Astrophys. J.
Lett. 601 L179; 614 L137 (2004)
For the model of pulsar evolution, the mean galactic merging rate of
BNS systems is R~83/ Myr. The 68%- and 95%-confidence level
intervals are 40 ± 140 and 20 ± 290 /Myr, respectively. The expected
detection rate of a gravitational-wave pulse from neighboring galaxies is
0.035 and 190 events per year for the initial (the detection limit 20 Mpc)
and advanced (the detection limit 350 Mpc) LIGO interferometers,
respectively. The corresponding 95%-confidence intervals are 0.007 ±
0.12 and 40 ± 660 events per year, respectively. The discovery of the
double pulsar J0737-3039 increased R by 6.4 times compared to earlier
calculations, because it dominates in computing the total probability, as
seen in Fig.
Examination of a broader class of evolutionary models of pulsars showed
that in all cases, accounting for the double pulsar J0737 ± 3039 increases
the BNS merging rate by 6 - 7 times, although the rates can differ by
more than 50 times in individual cases
Nonspherical Gravitational
Collapse (LIGO-VIRGO)
Uniform collapse without rotation
<~10
0.109 >~ 2 10
45
51
erg
erg for rapid rotation
Radiated during the collapse to maximal compression
Schwarzschild radius, minimal value of large semi-axis
Maximum GW radiation is during the bounce
A- the large axis, C f– minimal value of C, A/C f may be >> 1, K~0.01
The formal upper limit:
Never reached
arXiv:070526755

Time evolution of the GW amplitude h and maximum density for
three representative models with different rotation profiles and initial
rotation rates  i, at a distance d = 10 kpc .
Characteristic GW strain spectra h_c,sp at a distance d = 10 kpc to
the source for three representative models in GR with microphysical
EoS and deleptonization that do not undergo centrifugal bounce. As
for most other models the individual maxima f_max of their
frequency spectrum is very close to fmax ≃ 718 Hz.
Zeldovich “pancakes”, and emission
of very long GW
(Coherent Pulsar glitches ?)
1. A simplified model of the formation of structures in dark
matter
and a background of very long gravitational waves
Bisnovatyi-Kogan, MNRAS 347, 163 (2004)
2. Nonlinear Dynamics of self-gravitating uniform non-rotating
spheroid
B.-K., Tsupko Mon. Not. R. Astron. Soc. 386, 1398–1403 (2008)
Emission of very long gravitational waves
Bisnovatyi-Kogan (2004)
The energy emitted in GW:
If all dark matter had passed through the stage of pancake formation,
then very long GW have an average energy density in the Universe
 Amplitude of GW:
Observation of Gravitational Waves from a Binary Black Hole Merger
B. P. Abbott et al.*
(LIGO Scientific Collaboration and Virgo Collaboration)
On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer
Gravitational-Wave
Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps
upwards in
frequency from 35 to 250 Hz with a peak gravitational-wave strain h of 1.0 × 10−21. It matches
the waveform predicted by general relativity for the inspiral and merger of a pair of black holes
and the ringdown of the resulting single black hole. The signal was observed with a matchedfilter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203
000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity
distance of 410 (+160−180 )Mpc corresponding to a redshift z=0.09(+0.03 −0.04) . In the source
frame, the initial black hole masses are 36(+5 −4)M⊙ and 29(+4 −4)M⊙, and the final black
hole mass is 62(+4 −4)M⊙, with 3.0(+0.5 −0.5)M⊙c2 radiated in gravitational waves. All
uncertainties define 90% credible intervals.These observations demonstrate the existence of
binary stellar-mass black hole systems. This is the first direct detection of gravitational waves
and the first observation of a binary black hole merger.
PhysRevLett.116.061102 (2016)
Individual detector reliability:
This corresponds to a probability < 2 × 10−6 of observing
one or more noise events as strong as GW150914 during
the analysis time, equivalent to 4.6σ.
In the background
of this class there are four events with ηc ≥ 32.1, yielding a
false alarm rate for GW150914 of 1 in 8 400 years. This
corresponds to a false alarm probability of 5 × 10−6
equivalent to 4.4σ.
No detection of close binary with two massive BH in the Galaxy
No BH+NS (radio pulsar) binaries
GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary
Black Hole Coalescence
B. P. Abbott et al. (LIGO Scientific Collaboration and Virgo Collaboration)
Phys. Rev. Lett. 116, 241103
We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass
black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer
Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially
identified within 70 s by an online matched-filter search targeting binary coalescences.
Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a
significance greater than 5σ. The signal persisted in the LIGO frequency band for approximately 1 s,
increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak
gravitational strain of 3.4(+0.7−0.9)×10−22. The inferred source-frame initial black hole masses
are 14.2(+8.3−3.7)M⊙ and 7.5(+2.3−2.3)M⊙, and the final black hole mass is 20.8(+6.1−1.7)M⊙. We
find that at least one of the component black holes has spin greater than 0.2. This source is located at a
luminosity distance of 440(+180−190) Mpc corresponding to a redshift of 0.09(+0.03−0.04). All
uncertainties define a 90% credible interval. This second gravitational-wave observation provides
improved constraints on stellar populations and on deviations from general relativity.
Conclusions
1. GW have been discovered 25 years ago in observations of binary pulsar
2. GW are radiated mainly during the first bounce in non-spherical core
collapse, frequency 10-1000 Hz.
3. GW radiated during merging of NS +NS, NS+BH, BH+BH, have a chance
to be registered by LIGO. The last ones are probably registered.