Search for sub-solar mass ultracompact binaries in Advanced LIGO’s second
observing run
The LIGO Scientific Collaboration and The Virgo Collaboration
(Dated: May 28, 2019)
We present an Advanced LIGO and Advanced Virgo search for sub-solar mass ultracompact
objects in data obtained during Advanced LIGO’s second observing run. In contrast to a previous
search of Advanced LIGO data from the first observing run, this search includes the effects of
component spin on the gravitational waveform. We identify no viable gravitational wave candidates
consistent with sub-solar mass ultracompact binaries with at least one component between 0
.
2
−
1
.
0
M
. We use the null result to constrain the binary merger rate of (0
.
2
M
,
0
.
2
M
) binaries to
be less than 3
.
7
×
10
5
Gpc
−
3
yr
−
1
and the binary merger rate of (1
.
0
M
,
1
.
0
M
) binaries to be
less than 5
.
2
×
10
3
Gpc
−
3
yr
−
1
. Sub-solar mass ultracompact objects are not expected to form via
known stellar evolution channels, though it has been suggested that primordial density fluctuations
or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes
with sub-solar masses. Assuming a particular primordial black hole formation model, we constrain
a population of merging 0
.
2
M
black holes to account for less than 16% of the dark matter density
and a population of merging 1
.
0
M
black holes to account for less than 2% of the dark matter
density. We discuss how constraints on the merger rate and dark matter fraction may be extended
to arbitrary black hole population models that predict sub-solar mass binaries.
INTRODUCTION
Gravitational wave and multi-messenger astronomy
progressed remarkably in Advanced LIGO [1] and Ad-
vanced Virgo’s [2] second observing run, which included
the first observation of gravitational waves from a bi-
nary neutron star merger [3] and seven of the ten ob-
served binary black hole mergers [4–7]. These detections,
as well as the candidates presented in the gravitational
wave transient catalog (GWTC-1) [7], have led to a bet-
ter understanding of the populations of compact binaries
detectable by ground based interferometers [8]. These
observations, however, represent just a portion of the pa-
rameter space that Advanced LIGO and Advanced Virgo
currently search [9, 10] and are sensitive to [11]. We re-
port on an extension of the searched parameter space
in data obtained during O2 to binaries with component
masses
<
1
M
. This is the second search for sub-solar
mass ultracompact objects in Advanced LIGO data and
the fourth since initial LIGO [12–14], as well as the first
search to incorporate spin effects in the modeling of the
gravitational wave emission.
There is no known mechanism for the formation of
compact objects with masses well below a solar mass
within the standard model of particle physics and the
standard ΛCDM model of cosmology. Black holes must
be heavier than the Chandrasekhar limit (
∼
1
.
4
M
, set
by the mass of the proton [15]) while neutron stars are ex-
pected to have masses greater than about 0
.
9
M
[16, 17].
A detection of a sub-solar mass object in a merger would
therefore be a clear signal of new physics. Indeed, there
are several proposals that link sub-solar mass compact
objects to proposals for the nature of dark matter, which
makes up nearly 85% of the matter in the Universe. One
possibility is that black holes with masses accessible to
ground based interferometers could have formed deep in
the radiation era from the prompt collapse of large pri-
mordial over-densities on the scale of the early time Hub-
ble volume [18, 19]. The size and abundance of any such
primordial black holes depends on the spectrum of pri-
mordial perturbations and on the equation of state of the
early universe [20–23]. An alternative inflationary mech-
anism proposes that vacuum bubbles nucleated during
inflation may result in black holes (with masses that can
be around a solar mass) after inflation ends [24].
A different class of possibilities, explored more recently,
is motivated by ideas for the particle nature of dark mat-
ter. For example, dark matter may have a sufficiently
complex particle spectrum to support cooling mecha-
nisms that allow dense regions to collapse into black holes
at late times, in processes analogous to known astrophys-
ical processes [25]. Alternatively, dark matter may have
interactions with nuclear matter that allow it to collect
inside of neutron stars and trigger their collapse to black
holes [26–32]. The details of when dark matter can col-
lapse a neutron star to form a black hole or other exotic
compact object are still under investigation [33], but the
postulated black holes will have masses comparable to
the progenitor neutron star mass, or perhaps smaller if
some matter can be expelled by rapid rotation of the star
during collapse.
A detection of a sub-solar mass black hole would have
far-reaching implications. In the primordial black hole
scenario, the mass and abundance of the black holes
would constrain a combination of the spectrum of ini-
tial density perturbations on very small scales and the
equation of state of the Universe at a time when the typ-
ical mass inside a Hubble volume was of the order of the
black hole mass. For particle dark matter scenarios, the
abundance of sub-solar mass black holes would provide a
arXiv:1904.08976v3 [astro-ph.CO] 25 May 2019
2
direct estimate of the cooling rate for dark matter. The
black hole mass would constrain the masses of cosmolog-
ically abundant dark matter particles through, for exam-
ple, the Chandrasekhar relation for fermions [25] or anal-
ogous relations for non-interacting bosons [34, 35]. In the
case that all black holes are observed to be near but not
below the mass of neutron stars, the abundance of such
objects would constrain the dark matter-nucleon interac-
tion strength, as well as the dark matter self-interaction
strength and mass(es) [32].
This letter reports the results of a search for gravi-
tational waves from sub-solar mass ultracompact bina-
ries using data from Advanced LIGO’s second observing
run. No significant candidates consistent with a sub-
solar mass binary were identified. The null result places
the tightest constraints to date on the merger rate and
abundance of sub-solar mass ultracompact binaries. We
describe an extension of our merger rate constraints to
arbitrary populations and models under the assumption
that the horizon distance controls the sensitivity of the
search. We once more consider the merger rate con-
straints in the context of merging primordial black hole
populations contributing to the dark matter [14]. We de-
scribe how to extend the dark matter fraction parameter-
ization to other models by separating LIGO observables
from model dependent quantities. Finally, we conclude
with a discussion of the implications of this search.
SEARCH
We analyze data obtained from November 30, 2016 to
August 25, 2017 during Advanced LIGO’s second observ-
ing run (O2).
1
Noise artifacts are linearly subtracted
from the data; this includes strong sinusoidal features
in both detectors due to injected calibration frequencies
and the AC power grid, as well as laser beam jitter in the
LIGO-Hanford detector data [36]. 117.53 days of coin-
cident data remain after the application of data quality
cuts [37–41]. The Advanced Virgo interferometer com-
pleted commissioning and joined Advanced LIGO in Au-
gust 2017 for 15 days of triple coincident observation [7],
however, we only report on the analysis of data obtained
by the LIGO Hanford and LIGO Livingston interferom-
eters.
The search was conducted using publicly available
gravitational-wave analysis software [42–48]. The initial
stage of the search performed a matched-filter analysis
using a discrete bank of template waveforms generated
using the TaylorF2 frequency-domain, post-Newtonian
1
Data from Advanced LIGO’s second observing run is avail-
able from the Gravitational Wave Open Science Center with
and without noise sources linearly subtracted:
https://www.
gw-openscience.org
inspiral approximant [49]. The template bank used for
this search was designed to recover binaries with com-
ponent masses of 0
.
19
−
2
.
0
M
and total masses of
0
.
4
−
4
.
0
M
in the detector frame with 97% fidelity, as
in [14]. The search presented here, however, additionally
includes spin effects in the modeling of the gravitational
waveform. The bank is constructed to recover gravita-
tional waves originating from binaries with component
spins purely aligned or anti-aligned with the orbital an-
gular momentum, and with dimensionless spin magni-
tudes of 0
.
1 or less. The inclusion of spin effects required
denser placement of the waveforms in the template bank;
the resulting bank had 992 461 templates, which is nearly
twice as large as the non-spinning bank used in [14].
In order to reduce the computational burden, matched
filtering was only performed for a subset of Advanced
LIGO’s full sensitive band [11]. The choice to only an-
alyze the 45–1024 Hz band led to a detector averaged
signal-to-noise ratio (SNR) loss of 8% when compared to
the full
∼
10
−
2048Hz frequency band. This estimated
SNR loss is a property of Advanced LIGO’s noise curves
and is independent of the templates used in the search;
the discrete nature of the template bank causes an addi-
tional
.
3% loss in SNR.
Gravitational-wave candidates that were found coinci-
dent in both the Hanford and Livingston detectors were
ranked using the logarithm of the likelihood-ratio ,
L
[42–
44]. For a candidate with a likelihood-ratio of
L
∗
, we
assign a false-alarm-rate of
FAR(log
L
∗
) =
N
T
P
(log
L≥
log
L
∗
|
noise)
,
(1)
where
N
is the number of observed candidates,
T
is the total live time of the experiment, and
P
(log
L≥
log
L
∗
|
noise) describes the probability that
noise produces a candidate with a ranking statistic at
least as high as the candidate’s.
The search recovered the previously detected signal
GW170817 [3], which was observed along with an electro-
magnetic counterpart [50]. This signal is consistent with
a binary neutron star. No other viable gravitational wave
candidates were identified. The next loudest candidate
was consistent with noise and had a FAR of 3.25 per year.
CONSTRAINT ON BINARY MERGER RATE
As in [14], we consider nine populations of equal mass,
non-spinning binaries that are delta-function distributed
in mass, i.e.
m
i
∈{
0
.
2
,
0
.
3
,...,
1
.
0
}
. We injected 913 931
fake signals into our data; the injections were randomly
oriented and spaced uniformly in distance and isotrop-
ically across the sky. The recovered signals provide an
estimate of the pipeline’s detection efficiency as a func-
tion of source distance for each equal mass population.
3
FIG. 1. The constraint on the merger rate density for equal
mass binaries as a function of chirp mass. The two sets of lines
show the constraints for the O1 search [14] and the O2 search
presented here. The null result from O2 places bounds that
are
∼
3 times tighter than the O1 results. The majority of this
improvement is due to the increased coincident observing time
in Advanced LIGO’s second observing run (
∼
118 days vs.
∼
48 days), though the improved sensitivity of the detectors
led to an observed physical volume up to
∼
50% larger than
in O1 for sub-solar mass ultracompact binaries.
This in turn allows us to estimate the sensitive volume-
time accumulated for each mass bin. We once more use
the loudest event statistic formalism [51] to estimate the
upper limit on the binary merger rate to 90% confidence,
R
i
=
2
.
3
〈
V T
〉
i
(2)
These upper limits are shown for equal mass binaries
and as a function of chirp mass in Fig. 1. Although our
template bank includes systems with total mass up to
4
M
, we only place bounds on the merger rate of systems
where both components are
≤
1
M
. We estimate that
detector calibration uncertainties [7, 52, 53] and Monte
Carlo errors lead to an uncertainty in our rate constraint
of no more than 20%.
Advanced LIGO and Virgo’s horizon distance scales
as:
D
horizon
∝M
5
/
6
√
∫
f
max
f
min
f
−
7
/
3
S
n
(
f
)
df
(3)
where
S
n
(
f
) is the noise spectra of the detector and
f
min
and
f
max
are 45 Hz and 1024 Hz, respectively.
2
For a
2
The waveform model used to generate our template bank, Tay-
null result, we therefore expect
R
(
M
)
∝ M
−
15
/
6
pro-
vided the horizon distance controls the sensitivity of the
search. The observed power law dependence of the rate
constraint on the chirp mass is within
∼
4% of the ex-
pected
M
−
15
/
6
dependence; this is well within the error
bound on the rate upper limit and is strong evidence that
the chirp mass is the primary parameter that dictates the
sensitivity of the search. Therefore our upper limits from
equal mass systems also apply to unequal mass systems
within the range of mass ratios we have searched over.
For verification, we performed a small injection campaign
over five days of coincident data with injected component
masses distributed between 0
.
19
M
and 2
.
0
M
with at
least one component
<
1
.
0
M
. The search sensitivity re-
mained a function of the chirp mass; this implies that the
rate constraints found from the equal mass injection sets
can therefore be applied to systems with arbitrary mass
ratios provided that both component masses lie within
0
.
20
M
and 1
.
0
M
where our injection sets were per-
formed.
The Advanced LIGO and Virgo rate upper limit can
be expanded as:
R
(
M
1
,
M
2
) =
∫
M
2
M
1
R
(
M
)
×
ψ
(
M
) d
M
(4)
where
R
is the rate density as a function of chirp mass
and
ψ
(
M
) denotes the black hole population distribu-
tion in chirp mass. We ignore the effects of redshift due
to the small detector range for sub-solar mass binaries.
Setting
ψ
(
M
) =
δ
(
M
) then reveals the form of the LIGO
constraining rate density,
R
(
M
), which is shown in Fig-
ure 1. For a given model,
ψ
(
M
),
R
(
M
1
,
M
2
) provides
the LIGO rate constraint on that model for chirp masses
between
M
1
and
M
2
. The resulting rate constraints
allow direct comparison of sub-solar mass ultracompact
object models with LIGO observations.
GENERAL CONSTRAINTS ON SUB-SOLAR
MASS BLACK HOLE DARK MATTER
We convert our limits on the merger rate of sub-solar
mass ultracompact objects into a constraint on the abun-
dance of primordial black holes using our fiducial forma-
tion model [54] first developed in [19, 55] and used previ-
ously in LIGO analyses [12, 14]. We consider a popula-
tion of equal mass primordial black holes that is created
deep in the radiation era. We model the binary formation
lorF2, truncates the waveform at an upper frequency
f
ISCO
,
which corresponds to radiation from the innermost stable circular
orbit of a black hole binary with mass
M
total
. This frequency is
above
f
max
for all non-spinning waveforms in our template bank
and so does not impact
D
horizon
.
4
FIG. 2. Constraints on the fraction of dark matter com-
prised of delta-function distributions of primordial black holes
(
f
PBH
=
ρ
PBH
/ρ
DM
). Shown here are (pink) Advanced LIGO
constraints from the O2 ultracompact binary search presented
here (solid), (orange) microlensing constraints provided by the
OGLE (solid), EROS (dashed) [57], and MACHO (dotted)
collaborations [58], (cyan) dynamical constraints from obser-
vations of Segue I (solid) [59] and Eridanus II (dashed) [60]
dwarf galaxies, and (blue) supernova lensing constraints from
the Joint Light-curve Analysis (solid) and Union 2.1 (dashed)
datasets [61]. There is an inherent population model de-
pendency in each of these constraints.
Advanced LIGO
and Advanced Virgo results carry an additional dependence
on the binary fraction of the black hole population. Ad-
vanced LIGO and Advanced Virgo results use the Planck
“TT,TE,EE+lowP+lensing+ext” cosmology [62].
via three-body interactions, though others have consid-
ered the full field of tidal interactions [56]. By equating
the model’s predicted merger rate with the merger rate
upper limit provided by Advanced LIGO and Virgo, we
can numerically solve for the upper limit on the PBH
abundance. These constraints are shown in Figure 2.
3
This interpretation is highly model dependent; the
mass distribution, binary fraction, and binary formation
mechanisms all have a large effect on the expected present
day merger rate and consequently the bounds on the pri-
mordial black hole composition of the dark matter. The
Advanced LIGO and Virgo observables can be separated
3
The normalization of the PBH distribution used in our fiducial
model [54] differs by a factor of 2 from the normalization in [19].
As such, our fiducial model (used here and in [14]) predicts a
more conservative PBH merger rate and leads to less constraining
limits on
f
PBH
than would be attained using the model of [19].
from the model dependent terms:
f
CO
=
ρ
lim
ρ
CDM
×
1
f
obs
=
R
(
M
)
T
obs
M
ρ
CDM
×
1
f
obs
.
(5)
Here we use
f
CO
to refer to the dark matter fraction in
ultracompact objects instead of
f
PBH
to emphasize that
this is generally applicable to other compact object mod-
els that could contribute to the dark matter [25], and not
just PBHs. The first term,
ρ
lim
/ρ
CDM
, represents the up-
per limit on the fraction of the dark matter contained in
presently merging sub-solar mass ultracompact binaries.
In the second term,
f
obs
describes the fraction of sub-
solar mass ultracompact objects that are observable by
Advanced LIGO and Virgo for a particular model. This
is set by the binary fraction and the probability density
of binaries merging at present day. Note that the merger
rate density must be converted from a function of chirp
mass to total mass; this can be done by mapping to total
mass for each mass ratio on an equal chirp mass curve.
Equation (5) applies to any dark matter model that
predicts the formation of dark compact objects. The
abundance of those dark compact objects can then be
expressed as a fraction of the dark matter density.
CONCLUSION
We have presented the second Advanced LIGO and
Advanced Virgo search for sub-solar mass ultracompact
objects. No unambiguous sub-solar mass gravitational
wave candidates were identified. The null result allows
us to place tight constraints on the abundance of sub-
solar mass ultracompact binaries.
This work represents an expansion of previous initial
and Advanced LIGO and Advanced Virgo sub-solar mass
searches. First, we have broadened the searched param-
eter space to increase sensitivity to systems with non-
negligible component spins. Second, we have presented a
method to extend our constraints on the binary merger
rate to arbitrarily distributed populations that contain
sub-solar mass ultracompact objects. Combined with the
existing rate limits, this may already be enough to be-
gin constraining collapsed particulate dark matter mod-
els [25] or the cross section of nuclear interactions [26–
30, 32]. Finally, we have provided a method to separate
Advanced LIGO and Advanced Virgo observables from
model dependent terms in our interpretation of the lim-
its on primordial black hole dark matter.
Ground based interferometer searches for sub-solar
mass ultracompact objects will continue to inform cosmo-
logical and particle physics scenarios. Advanced LIGO
and Advanced Virgo have begun a year long observing
run in early 2019, with improved sensitivities [63]. Ad-
vanced Virgo will have more coincident time with the
Advanced LIGO detectors over its next observing run,
5
which will improve network sensitivity and aid in further
constraining the above scenarios.
ACKNOWLEDGMENTS
The authors gratefully acknowledge the support of the
United States National Science Foundation (NSF) for
the construction and operation of the LIGO Laboratory
and Advanced LIGO as well as the Science and Tech-
nology Facilities Council (STFC) of the United King-
dom, the Max-Planck-Society (MPS), and the State of
Niedersachsen/Germany for support of the construction
of Advanced LIGO and construction and operation of
the GEO600 detector. Additional support for Advanced
LIGO was provided by the Australian Research Council.
The authors gratefully acknowledge the Italian Istituto
Nazionale di Fisica Nucleare (INFN), the French Centre
National de la Recherche Scientifique (CNRS) and the
Foundation for Fundamental Research on Matter sup-
ported by the Netherlands Organisation for Scientific Re-
search, for the construction and operation of the Virgo
detector and the creation and support of the EGO consor-
tium. The authors also gratefully acknowledge research
support from these agencies as well as by the Council
of Scientific and Industrial Research of India, the De-
partment of Science and Technology, India, the Science
& Engineering Research Board (SERB), India, the Min-
istry of Human Resource Development, India, the Span-
ish Agencia Estatal de Investigaci ́on, the Vicepresid`encia
i Conselleria d’Innovaci ́o, Recerca i Turisme and the Con-
selleria d’Educaci ́o i Universitat del Govern de les Illes
Balears, the Conselleria d’Educaci ́o, Investigaci ́o, Cul-
tura i Esport de la Generalitat Valenciana, the National
Science Centre of Poland, the Swiss National Science
Foundation (SNSF), the Russian Foundation for Basic
Research, the Russian Science Foundation, the European
Commission, the European Regional Development Funds
(ERDF), the Royal Society, the Scottish Funding Coun-
cil, the Scottish Universities Physics Alliance, the Hun-
garian Scientific Research Fund (OTKA), the Lyon In-
stitute of Origins (LIO), the Paris
ˆ
Ile-de-France Region,
the National Research, Development and Innovation Of-
fice Hungary (NKFI), the National Research Foundation
of Korea, Industry Canada and the Province of Ontario
through the Ministry of Economic Development and In-
novation, the Natural Science and Engineering Research
Council Canada, the Canadian Institute for Advanced
Research, the Brazilian Ministry of Science, Technol-
ogy, Innovations, and Communications, the International
Center for Theoretical Physics South American Insti-
tute for Fundamental Research (ICTP-SAIFR), the Re-
search Grants Council of Hong Kong, the National Natu-
ral Science Foundation of China (NSFC), the Leverhulme
Trust, the Research Corporation, the Ministry of Science
and Technology (MOST), Taiwan and the Kavli Foun-
dation. The authors gratefully acknowledge the support
of the NSF, STFC, MPS, INFN, CNRS and the State of
Niedersachsen/Germany for provision of computational
resources. Computing resources and personnel for this
project were provided by the Pennsylvania State Univer-
sity. This article has been assigned the document number
ligo-p1900037.
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Authors
B. P. Abbott,
1
R. Abbott,
1
T. D. Abbott,
2
S. Abraham,
3
F. Acernese,
4, 5
K. Ackley,
6
C. Adams,
7
R. X. Adhikari,
1
V. B. Adya,
8
C. Affeldt,
9, 10
M. Agathos,
11, 12
K. Agatsuma,
13
N. Aggarwal,
14
O. D. Aguiar,
15
L. Aiello,
16, 17
A. Ain,
3
P. Ajith,
18
G. Allen,
19
A. Allocca,
20, 21
M. A. Aloy,
22
P. A. Altin,
8
A. Amato,
23
S. Anand,
1
A. Ananyeva,
1
S. B. Anderson,
1
W. G. Anderson,
24
S. V. Angelova,
25
S. Antier,
26
S. Appert,
1
K. Arai,
1
M. C. Araya,
1
J. S. Areeda,
27
M. Ar`ene,
26
N. Arnaud,
28, 29
S. M. Aronson,
30
K. G. Arun,
31
S. Ascenzi,
16, 32
G. Ashton,
6
S. M. Aston,
7
P. Astone,
33
F. Aubin,
34
P. Aufmuth,
10
K. AultONeal,
35
C. Austin,
2
V. Avendano,
36
A. Avila-Alvarez,
27
S. Babak,
26
P. Bacon,
26
F. Badaracco,
16, 17
M. K. M. Bader,
37
S. Bae,
38
J. Baird,
26
P. T. Baker,
39
F. Baldaccini,
40, 41
G. Ballardin,
29
S. W. Ballmer,
42
A. Bals,
35
S. Banagiri,
43
J. C. Barayoga,
1
C. Barbieri,
44, 45
S. E. Barclay,
46
B. C. Barish,
1
D. Barker,
47
K. Barkett,
48
S. Barnum,
14
F. Barone,
49, 5
B. Barr,
46
L. Barsotti,
14
M. Barsuglia,
26
D. Barta,
50
J. Bartlett,
47
I. Bartos,
30
R. Bassiri,
51
A. Basti,
20, 21
M. Bawaj,
52, 41
J. C. Bayley,
46
M. Bazzan,
53, 54
B. B ́ecsy,
55
M. Bejger,
26, 56
I. Belahcene,
28
A. S. Bell,
46
D. Beniwal,
57
M. G. Benjamin,
35
B. K. Berger,
51
G. Bergmann,
9, 10
S. Bernuzzi,
11
C. P. L. Berry,
58
D. Bersanetti,
59
A. Bertolini,
37
J. Betzwieser,
7
R. Bhandare,
60
J. Bidler,
27
E. Biggs,
24
I. A. Bilenko,
61
S. A. Bilgili,
39
G. Billingsley,
1
R. Birney,
25
O. Birnholtz,
62
S. Biscans,
1, 14
M. Bischi,
63, 64
S. Biscoveanu,
14
A. Bisht,
10
M. Bitossi,
29, 21
M. A. Bizouard,
65
J. K. Blackburn,
1
J. Blackman,
48
C. D. Blair,
7
D. G. Blair,
66
R. M. Blair,
47
S. Bloemen,
67
F. Bobba,
68, 69
N. Bode,
9, 10
M. Boer,
65
Y. Boetzel,
70
G. Bogaert,
65
F. Bondu,
71
R. Bonnand,
34
P. Booker,
9, 10
B. A. Boom,
37
R. Bork,
1
V. Boschi,
29
S. Bose,
3
V. Bossilkov,
66
J. Bosveld,
66
Y. Bouffanais,
53, 54
A. Bozzi,
29
C. Bradaschia,
21
P. R. Brady,
24
A. Bramley,
7
M. Branchesi,
16, 17
J. E. Brau,
72
M. Breschi,
11
T. Briant,
73
J. H. Briggs,
46
F. Brighenti,
63, 64
A. Brillet,
65
M. Brinkmann,
9, 10
P. Brockill,
24
A. F. Brooks,
1
J. Brooks,
29
D. D. Brown,
57
S. Brunett,
1
A. Buikema,
14
T. Bulik,
74
H. J. Bulten,
75, 37
A. Buonanno,
76, 77
D. Buskulic,
34
C. Buy,
26
R. L. Byer,
51
M. Cabero,
9, 10
L. Cadonati,
78
G. Cagnoli,
79
C. Cahillane,
1
J. Calder ́on Bustillo,
6
T. A. Callister,
1
E. Calloni,
80, 5
J. B. Camp,
81
W. A. Campbell,
6, 59
K. C. Cannon,
82
H. Cao,
57
J. Cao,
83
G. Carapella,
68, 69
F. Carbognani,
29
S. Caride,
84
M. F. Carney,
58
G. Carullo,
20, 21
J. Casanueva Diaz,
21
C. Casentini,
85, 32
S. Caudill,
37
M. Cavagli`a,
86, 87
F. Cavalier,
28
R. Cavalieri,
29
G. Cella,
21
P. Cerd ́a-Dur ́an,
22
E. Cesarini,
88, 32
O. Chaibi,
65
K. Chakravarti,
3
S. J. Chamberlin,
89
M. Chan,
46
S. Chao,
90
P. Charlton,
91
E. A. Chase,
58
E. Chassande-Mottin,
26
D. Chatterjee,
24
M. Chaturvedi,
60
K. Chatziioannou,
92
B. D. Cheeseboro,
39
H. Y. Chen,
93
X. Chen,
66
Y. Chen,
48
H.-P. Cheng,
30
C. K. Cheong,
94
H. Y. Chia,
30
F. Chiadini,
95, 69
A. Chincarini,
59
A. Chiummo,
29
G. Cho,
96
H. S. Cho,
97
M. Cho,
77
N. Christensen,
98, 65
Q. Chu,
66
S. Chua,
73
K. W. Chung,
94
S. Chung,
66
G. Ciani,
53, 54
M. Cie ́slar,
56
A. A. Ciobanu,
57
R. Ciolfi,
99, 54
F. Cipriano,
65
A. Cirone,
100, 59
F. Clara,
47
J. A. Clark,
78
P. Clearwater,
101
F. Cleva,
65
E. Coccia,
16, 17
P.-F. Cohadon,
73
D. Cohen,
28
M. Colleoni,
102
C. G. Collette,
103
C. Collins,
13
M. Colpi,
44, 45
L. R. Cominsky,
104
M. Constancio Jr.,
15
L. Conti,
54
S. J. Cooper,
13
P. Corban,
7
T. R. Corbitt,
2
I. Cordero-Carri ́on,
105
S. Corezzi,
40, 41
K. R. Corley,
106
N. Cornish,
55
D. Corre,
28
A. Corsi,
84
S. Cortese,
29
C. A. Costa,
15
R. Cotesta,
76
M. W. Coughlin,
1
S. B. Coughlin,
107, 58
J.-P. Coulon,
65
S. T. Countryman,
106
P. Couvares,
1
P. B. Covas,
102
E. E. Cowan,
78
D. M. Coward,
66
M. J. Cowart,
7
D. C. Coyne,
1
R. Coyne,
108
J. D. E. Creighton,
24
T. D. Creighton,
109
J. Cripe,
2
M. Croquette,
73
S. G. Crowder,
110
T. J. Cullen,
2
A. Cumming,
46
L. Cunningham,
46
E. Cuoco,
29
T. Dal Canton,
81
8
G. D ́alya,
111
B. D’Angelo,
100, 59
S. L. Danilishin,
9, 10
S. D’Antonio,
32
K. Danzmann,
10, 9
A. Dasgupta,
112
C. F. Da Silva Costa,
30
L. E. H. Datrier,
46
V. Dattilo,
29
I. Dave,
60
M. Davier,
28
D. Davis,
42
E. J. Daw,
113
D. DeBra,
51
M. Deenadayalan,
3
J. Degallaix,
23
M. De Laurentis,
80, 5
S. Del ́eglise,
73
W. Del Pozzo,
20, 21
L. M. DeMarchi,
58
N. Demos,
14
T. Dent,
114
R. De Pietri,
115, 116
R. De Rosa,
80, 5
C. De Rossi,
23, 29
R. DeSalvo,
117
O. de Varona,
9, 10
S. Dhurandhar,
3
M. C. D ́ıaz,
109
T. Dietrich,
37
L. Di Fiore,
5
C. DiFronzo,
13
C. Di Giorgio,
68, 69
F. Di Giovanni,
22
M. Di Giovanni,
118, 119
T. Di Girolamo,
80, 5
A. Di Lieto,
20, 21
B. Ding,
103
S. Di Pace,
120, 33
I. Di Palma,
120, 33
F. Di Renzo,
20, 21
A. K. Divakarla,
30
A. Dmitriev,
13
Z. Doctor,
93
F. Donovan,
14
K. L. Dooley,
107, 86
S. Doravari,
3
I. Dorrington,
107
T. P. Downes,
24
M. Drago,
16, 17
J. C. Driggers,
47
Z. Du,
83
J.-G. Ducoin,
28
P. Dupej,
46
O. Durante,
68, 69
S. E. Dwyer,
47
P. J. Easter,
6
G. Eddolls,
46
T. B. Edo,
113
A. Effler,
7
P. Ehrens,
1
J. Eichholz,
8
S. S. Eikenberry,
30
M. Eisenmann,
34
R. A. Eisenstein,
14
L. Errico,
80, 5
R. C. Essick,
93
H. Estelles,
102
D. Estevez,
34
Z. B. Etienne,
39
T. Etzel,
1
M. Evans,
14
T. M. Evans,
7
V. Fafone,
85, 32, 16
S. Fairhurst,
107
X. Fan,
83
S. Farinon,
59
B. Farr,
72
W. M. Farr,
13
E. J. Fauchon-Jones,
107
M. Favata,
36
M. Fays,
113
M. Fazio,
121
C. Fee,
122
J. Feicht,
1
M. M. Fejer,
51
F. Feng,
26
A. Fernandez-Galiana,
14
I. Ferrante,
20, 21
E. C. Ferreira,
15
T. A. Ferreira,
15
F. Fidecaro,
20, 21
I. Fiori,
29
D. Fiorucci,
16, 17
M. Fishbach,
93
R. P. Fisher,
123
J. M. Fishner,
14
R. Fittipaldi,
124, 69
M. Fitz-Axen,
43
V. Fiumara,
125, 69
R. Flaminio,
34, 126
M. Fletcher,
46
E. Floden,
43
E. Flynn,
27
H. Fong,
82
J. A. Font,
22, 127
P. W. F. Forsyth,
8
J.-D. Fournier,
65
Francisco Hernandez Vivanco,
6
S. Frasca,
120, 33
F. Frasconi,
21
Z. Frei,
111
A. Freise,
13
R. Frey,
72
V. Frey,
28
P. Fritschel,
14
V. V. Frolov,
7
G. Fronz`e,
128
P. Fulda,
30
M. Fyffe,
7
H. A. Gabbard,
46
B. U. Gadre,
76
S. M. Gaebel,
13
J. R. Gair,
129
L. Gammaitoni,
40
S. G. Gaonkar,
3
C. Garc ́ıa-Quir ́os,
102
F. Garufi,
80, 5
B. Gateley,
47
S. Gaudio,
35
G. Gaur,
130
V. Gayathri,
131
G. Gemme,
59
E. Genin,
29
A. Gennai,
21
D. George,
19
J. George,
60
L. Gergely,
132
S. Ghonge,
78
Abhirup Ghosh,
76
Archisman Ghosh,
37
S. Ghosh,
24
B. Giacomazzo,
118, 119
J. A. Giaime,
2, 7
K. D. Giardina,
7
D. R. Gibson,
133
K. Gill,
106
L. Glover,
134
J. Gniesmer,
135
P. Godwin,
89
E. Goetz,
47
R. Goetz,
30
B. Goncharov,
6
G. Gonz ́alez,
2
J. M. Gonzalez Castro,
20, 21
A. Gopakumar,
136
S. E. Gossan,
1
M. Gosselin,
29, 20, 21
R. Gouaty,
34
B. Grace,
8
A. Grado,
137, 5
M. Granata,
23
A. Grant,
46
S. Gras,
14
P. Grassia,
1
C. Gray,
47
R. Gray,
46
G. Greco,
63, 64
A. C. Green,
30
R. Green,
107
E. M. Gretarsson,
35
A. Grimaldi,
118, 119
S. J. Grimm,
16, 17
P. Groot,
67
H. Grote,
107
S. Grunewald,
76
P. Gruning,
28
G. M. Guidi,
63, 64
H. K. Gulati,
112
Y. Guo,
37
A. Gupta,
89
Anchal Gupta,
1
P. Gupta,
37
E. K. Gustafson,
1
R. Gustafson,
138
L. Haegel,
102
O. Halim,
17, 16
B. R. Hall,
139
E. D. Hall,
14
E. Z. Hamilton,
107
G. Hammond,
46
M. Haney,
70
M. M. Hanke,
9, 10
J. Hanks,
47
C. Hanna,
89
M. D. Hannam,
107
O. A. Hannuksela,
94
T. J. Hansen,
35
J. Hanson,
7
T. Harder,
65
T. Hardwick,
2
K. Haris,
18
J. Harms,
16, 17
G. M. Harry,
140
I. W. Harry,
141
R. K. Hasskew,
7
C. J. Haster,
14
K. Haughian,
46
F. J. Hayes,
46
J. Healy,
62
A. Heidmann,
73
M. C. Heintze,
7
H. Heitmann,
65
F. Hellman,
142
P. Hello,
28
G. Hemming,
29
M. Hendry,
46
I. S. Heng,
46
J. Hennig,
9, 10
M. Heurs,
9, 10
S. Hild,
46
T. Hinderer,
143, 37, 144
S. Hochheim,
9, 10
D. Hofman,
23
A. M. Holgado,
19
N. A. Holland,
8
K. Holt,
7
D. E. Holz,
93
P. Hopkins,
107
C. Horst,
24
J. Hough,
46
E. J. Howell,
66
C. G. Hoy,
107
Y. Huang,
14
M. T. H ̈ubner,
6
E. A. Huerta,
19
D. Huet,
28
B. Hughey,
35
V. Hui,
34
S. Husa,
102
S. H. Huttner,
46
T. Huynh-Dinh,
7
B. Idzkowski,
74
A. Iess,
85, 32
H. Inchauspe,
30
C. Ingram,
57
R. Inta,
84
G. Intini,
120, 33
B. Irwin,
122
H. N. Isa,
46
J.-M. Isac,
73
M. Isi,
14
B. R. Iyer,
18
T. Jacqmin,
73
S. J. Jadhav,
145
K. Jani,
78
N. N. Janthalur,
145
P. Jaranowski,
146
D. Jariwala,
30
A. C. Jenkins,
147
J. Jiang,
30
D. S. Johnson,
19
A. W. Jones,
13
D. I. Jones,
148
J. D. Jones,
47
R. Jones,
46
R. J. G. Jonker,
37
L. Ju,
66
J. Junker,
9, 10
C. V. Kalaghatgi,
107
V. Kalogera,
58
B. Kamai,
1
S. Kandhasamy,
3
G. Kang,
38
J. B. Kanner,
1
S. J. Kapadia,
24
S. Karki,
72
R. Kashyap,
18
M. Kasprzack,
1
S. Katsanevas,
29
E. Katsavounidis,
14
W. Katzman,
7
S. Kaufer,
10
K. Kawabe,
47
N. V. Keerthana,
3
F. K ́ef ́elian,
65
D. Keitel,
141
R. Kennedy,
113
J. S. Key,
149
F. Y. Khalili,
61
I. Khan,
16, 32
S. Khan,
9, 10
E. A. Khazanov,
150
N. Khetan,
16, 17
M. Khursheed,
60
N. Kijbunchoo,
8
Chunglee Kim,
151
J. C. Kim,
152
K. Kim,
94
W. Kim,
57
W. S. Kim,
153
Y.-M. Kim,
154
C. Kimball,
58
P. J. King,
47
M. Kinley-Hanlon,
46
R. Kirchhoff,
9, 10
J. S. Kissel,
47
L. Kleybolte,
135
J. H. Klika,
24
S. Klimenko,
30
T. D. Knowles,
39
P. Koch,
9, 10
S. M. Koehlenbeck,
9, 10
G. Koekoek,
37, 155
S. Koley,
37
V. Kondrashov,
1
A. Kontos,
156
N. Koper,
9, 10
M. Korobko,
135
W. Z. Korth,
1
M. Kovalam,
66
D. B. Kozak,
1
C. Kr ̈amer,
9, 10
V. Kringel,
9, 10
N. Krishnendu,
31
A. Kr ́olak,
157, 158
N. Krupinski,
24
G. Kuehn,
9, 10
A. Kumar,
145
P. Kumar,
159
Rahul Kumar,
47
Rakesh Kumar,
112
L. Kuo,
90
A. Kutynia,
157
S. Kwang,
24
B. D. Lackey,
76
D. Laghi,
20, 21
K. H. Lai,
94
T. L. Lam,
94
M. Landry,
47
B. B. Lane,
14
R. N. Lang,
160
J. Lange,
62
B. Lantz,
51
R. K. Lanza,
14
A. Lartaux-Vollard,
28
P. D. Lasky,
6
M. Laxen,
7
A. Lazzarini,
1
C. Lazzaro,
54
P. Leaci,
120, 33
S. Leavey,
9, 10
Y. K. Lecoeuche,
47
C. H. Lee,
97
H. K. Lee,
161
H. M. Lee,
162
H. W. Lee,
152
J. Lee,
96
K. Lee,
46
J. Lehmann,
9, 10
A. K. Lenon,
39
N. Leroy,
28
N. Letendre,
34
Y. Levin,
6
A. Li,
94
J. Li,
83
K. J. L. Li,
94
T. G. F. Li,
94
X. Li,
48
F. Lin,
6
F. Linde,
163, 37
S. D. Linker,
134
9
T. B. Littenberg,
164
J. Liu,
66
X. Liu,
24
M. Llorens-Monteagudo,
22
R. K. L. Lo,
94, 1
L. T. London,
14
A. Longo,
165, 166
M. Lorenzini,
16, 17
V. Loriette,
167
M. Lormand,
7
G. Losurdo,
21
J. D. Lough,
9, 10
C. O. Lousto,
62
G. Lovelace,
27
M. E. Lower,
168
H. L ̈uck,
10, 9
D. Lumaca,
85, 32
A. P. Lundgren,
141
R. Lynch,
14
Y. Ma,
48
R. Macas,
107
S. Macfoy,
25
M. MacInnis,
14
D. M. Macleod,
107
A. Macquet,
65
I. Maga ̃na Hernandez,
24
F. Maga ̃na-Sandoval,
30
R. M. Magee,
89
E. Majorana,
33
I. Maksimovic,
167
A. Malik,
60
N. Man,
65
V. Mandic,
43
V. Mangano,
46, 120, 33
G. L. Mansell,
47, 14
M. Manske,
24
M. Mantovani,
29
M. Mapelli,
53, 54
F. Marchesoni,
52, 41
F. Marion,
34
S. M ́arka,
106
Z. M ́arka,
106
C. Markakis,
19
A. S. Markosyan,
51
A. Markowitz,
1
E. Maros,
1
A. Marquina,
105
S. Marsat,
26
F. Martelli,
63, 64
I. W. Martin,
46
R. M. Martin,
36
V. Martinez,
79
D. V. Martynov,
13
H. Masalehdan,
135
K. Mason,
14
E. Massera,
113
A. Masserot,
34
T. J. Massinger,
1
M. Masso-Reid,
46
S. Mastrogiovanni,
26
A. Matas,
76
F. Matichard,
1, 14
L. Matone,
106
N. Mavalvala,
14
J. J. McCann,
66
R. McCarthy,
47
D. E. McClelland,
8
P. McClincy,
89
S. McCormick,
7
L. McCuller,
14
S. C. McGuire,
169
C. McIsaac,
141
J. McIver,
1
D. J. McManus,
8
T. McRae,
8
S. T. McWilliams,
39
D. Meacher,
24
G. D. Meadors,
6
M. Mehmet,
9, 10
A. K. Mehta,
18
J. Meidam,
37
E. Mejuto Villa,
117, 69
A. Melatos,
101
G. Mendell,
47
R. A. Mercer,
24
L. Mereni,
23
K. Merfeld,
72
E. L. Merilh,
47
M. Merzougui,
65
S. Meshkov,
1
C. Messenger,
46
C. Messick,
89
F. Messina,
44, 45
R. Metzdorff,
73
P. M. Meyers,
101
F. Meylahn,
9, 10
A. Miani,
118, 119
H. Miao,
13
C. Michel,
23
H. Middleton,
101
L. Milano,
80, 5
A. L. Miller,
30, 120, 33
M. Millhouse,
101
J. C. Mills,
107
M. C. Milovich-Goff,
134
O. Minazzoli,
65, 170
Y. Minenkov,
32
A. Mishkin,
30
C. Mishra,
171
T. Mistry,
113
S. Mitra,
3
V. P. Mitrofanov,
61
G. Mitselmakher,
30
R. Mittleman,
14
G. Mo,
98
D. Moffa,
122
K. Mogushi,
86
S. R. P. Mohapatra,
14
M. Molina-Ruiz,
142
M. Mondin,
134
M. Montani,
63, 64
C. J. Moore,
13
D. Moraru,
47
F. Morawski,
56
G. Moreno,
47
S. Morisaki,
82
B. Mours,
34
C. M. Mow-Lowry,
13
F. Muciaccia,
120, 33
Arunava Mukherjee,
9, 10
D. Mukherjee,
24
S. Mukherjee,
109
Subroto Mukherjee,
112
N. Mukund,
9, 10, 3
A. Mullavey,
7
J. Munch,
57
E. A. Mu ̃niz,
42
M. Muratore,
35
P. G. Murray,
46, 128, 172
I. Nardecchia,
85, 32
L. Naticchioni,
120, 33
R. K. Nayak,
173
B. F. Neil,
66
J. Neilson,
117, 69
G. Nelemans,
67, 37
T. J. N. Nelson,
7
M. Nery,
9, 10
A. Neunzert,
138
L. Nevin,
1
K. Y. Ng,
14
S. Ng,
57
C. Nguyen,
26
P. Nguyen,
72
D. Nichols,
143, 37
S. A. Nichols,
2
S. Nissanke,
143, 37
F. Nocera,
29
C. North,
107
L. K. Nuttall,
141
M. Obergaulinger,
22, 174
J. Oberling,
47
B. D. O’Brien,
30
G. Oganesyan,
16, 17
G. H. Ogin,
175
J. J. Oh,
153
S. H. Oh,
153
F. Ohme,
9, 10
H. Ohta,
82
M. A. Okada,
15
M. Oliver,
102
P. Oppermann,
9, 10
Richard J. Oram,
7
B. O’Reilly,
7
R. G. Ormiston,
43
L. F. Ortega,
30
R. O’Shaughnessy,
62
S. Ossokine,
76
D. J. Ottaway,
57
H. Overmier,
7
B. J. Owen,
84
A. E. Pace,
89
G. Pagano,
20, 21
M. A. Page,
66
G. Pagliaroli,
16, 17
A. Pai,
131
S. A. Pai,
60
J. R. Palamos,
72
O. Palashov,
150
C. Palomba,
33
H. Pan,
90
P. K. Panda,
145
P. T. H. Pang,
94, 37
C. Pankow,
58
F. Pannarale,
120, 33
B. C. Pant,
60
F. Paoletti,
21
A. Paoli,
29
A. Parida,
3
W. Parker,
7, 169
D. Pascucci,
46, 37
A. Pasqualetti,
29
R. Passaquieti,
20, 21
D. Passuello,
21
M. Patil,
158
B. Patricelli,
20, 21
E. Payne,
6
B. L. Pearlstone,
46
T. C. Pechsiri,
30
A. J. Pedersen,
42
M. Pedraza,
1
R. Pedurand,
23, 176
A. Pele,
7
S. Penn,
177
A. Perego,
118, 119
C. J. Perez,
47
C. P ́erigois,
34
A. Perreca,
118, 119
J. Petermann,
135
H. P. Pfeiffer,
76
M. Phelps,
9, 10
K. S. Phukon,
3
O. J. Piccinni,
120, 33
M. Pichot,
65
F. Piergiovanni,
63, 64
V. Pierro,
117, 69
G. Pillant,
29
L. Pinard,
23
I. M. Pinto,
117, 69, 88
M. Pirello,
47
M. Pitkin,
46
W. Plastino,
165, 166
R. Poggiani,
20, 21
D. Y. T. Pong,
94
S. Ponrathnam,
3
P. Popolizio,
29
E. K. Porter,
26
J. Powell,
168
A. K. Prajapati,
112
J. Prasad,
3
K. Prasai,
51
R. Prasanna,
145
G. Pratten,
102
T. Prestegard,
24
M. Principe,
117, 88, 69
G. A. Prodi,
118, 119
L. Prokhorov,
13
M. Punturo,
41
P. Puppo,
33
M. P ̈urrer,
76
H. Qi,
107
V. Quetschke,
109
P. J. Quinonez,
35
F. J. Raab,
47
G. Raaijmakers,
143, 37
H. Radkins,
47
N. Radulesco,
65
P. Raffai,
111
S. Raja,
60
C. Rajan,
60
B. Rajbhandari,
84
M. Rakhmanov,
109
K. E. Ramirez,
109
A. Ramos-Buades,
102
Javed Rana,
3
K. Rao,
58
P. Rapagnani,
120, 33
V. Raymond,
107
M. Razzano,
20, 21
J. Read,
27
T. Regimbau,
34
L. Rei,
59
S. Reid,
25
D. H. Reitze,
1, 30
P. Rettegno,
128, 178
F. Ricci,
120, 33
C. J. Richardson,
35
J. W. Richardson,
1
P. M. Ricker,
19
G. Riemenschneider,
178, 128
K. Riles,
138
M. Rizzo,
58
N. A. Robertson,
1, 46
F. Robinet,
28
A. Rocchi,
32
L. Rolland,
34
J. G. Rollins,
1
V. J. Roma,
72
M. Romanelli,
71
R. Romano,
4, 5
C. L. Romel,
47
J. H. Romie,
7
C. A. Rose,
24
D. Rose,
27
K. Rose,
122
D. Rosi ́nska,
74
S. G. Rosofsky,
19
M. P. Ross,
179
S. Rowan,
46
A. R ̈udiger,
9, 10,
∗
P. Ruggi,
29
G. Rutins,
133
K. Ryan,
47
S. Sachdev,
89
T. Sadecki,
47
M. Sakellariadou,
147
O. S. Salafia,
180, 44, 45
L. Salconi,
29
M. Saleem,
31
A. Samajdar,
37
L. Sammut,
6
E. J. Sanchez,
1
L. E. Sanchez,
1
N. Sanchis-Gual,
181
J. R. Sanders,
182
K. A. Santiago,
36
E. Santos,
65
N. Sarin,
6
B. Sassolas,
23
B. S. Sathyaprakash,
89, 107
O. Sauter,
138, 34
R. L. Savage,
47
P. Schale,
72
M. Scheel,
48
J. Scheuer,
58
P. Schmidt,
13, 67
R. Schnabel,
135
R. M. S. Schofield,
72
A. Sch ̈onbeck,
135
E. Schreiber,
9, 10
B. W. Schulte,
9, 10
B. F. Schutz,
107
J. Scott,
46
S. M. Scott,
8
E. Seidel,
19
D. Sellers,
7
A. S. Sengupta,
183
N. Sennett,
76
D. Sentenac,
29
V. Sequino,
59
A. Sergeev,
150
Y. Setyawati,
9, 10
D. A. Shaddock,
8
T. Shaffer,
47
M. S. Shahriar,
58
M. B. Shaner,
134
A. Sharma,
16, 17
P. Sharma,
60
P. Shawhan,
77
H. Shen,
19
R. Shink,
184
D. H. Shoemaker,
14
D. M. Shoemaker,
78
K. Shukla,
142
S. ShyamSundar,
60
K. Siellez,
78
M. Sieniawska,
56
D. Sigg,
47
10
L. P. Singer,
81
D. Singh,
89
N. Singh,
74
A. Singhal,
16, 33
A. M. Sintes,
102
S. Sitmukhambetov,
109
V. Skliris,
107
B. J. J. Slagmolen,
8
T. J. Slaven-Blair,
66
J. R. Smith,
27
R. J. E. Smith,
6
S. Somala,
185
E. J. Son,
153
S. Soni,
2
B. Sorazu,
46
F. Sorrentino,
59
T. Souradeep,
3
E. Sowell,
84
A. P. Spencer,
46
M. Spera,
53, 54
A. K. Srivastava,
112
V. Srivastava,
42
K. Staats,
58
C. Stachie,
65
M. Standke,
9, 10
D. A. Steer,
26
M. Steinke,
9, 10
J. Steinlechner,
135, 46
S. Steinlechner,
135
D. Steinmeyer,
9, 10
S. P. Stevenson,
168
D. Stocks,
51
R. Stone,
109
D. J. Stops,
13
K. A. Strain,
46
G. Stratta,
186, 64
S. E. Strigin,
61
A. Strunk,
47
R. Sturani,
187
A. L. Stuver,
188
V. Sudhir,
14
T. Z. Summerscales,
189
L. Sun,
1
S. Sunil,
112
A. Sur,
56
J. Suresh,
82
P. J. Sutton,
107
B. L. Swinkels,
37
M. J. Szczepa ́nczyk,
35
M. Tacca,
37
S. C. Tait,
46
C. Talbot,
6
D. B. Tanner,
30
D. Tao,
1
M. T ́apai,
132
A. Tapia,
27
J. D. Tasson,
98
R. Taylor,
1
R. Tenorio,
102
L. Terkowski,
135
M. Thomas,
7
P. Thomas,
47
S. R. Thondapu,
60
K. A. Thorne,
7
E. Thrane,
6
Shubhanshu Tiwari,
118, 119
Srishti Tiwari,
136
V. Tiwari,
107
K. Toland,
46
M. Tonelli,
20, 21
Z. Tornasi,
46
A. Torres-Forn ́e,
190
C. I. Torrie,
1
D. T ̈oyr ̈a,
13
F. Travasso,
29, 41
G. Traylor,
7
M. C. Tringali,
74
A. Tripathee,
138
A. Trovato,
26
L. Trozzo,
191, 21
K. W. Tsang,
37
M. Tse,
14
R. Tso,
48
L. Tsukada,
82
D. Tsuna,
82
T. Tsutsui,
82
D. Tuyenbayev,
109
K. Ueno,
82
D. Ugolini,
192
C. S. Unnikrishnan,
136
A. L. Urban,
2
S. A. Usman,
93
H. Vahlbruch,
10
G. Vajente,
1
G. Valdes,
2
M. Valentini,
118, 119
N. van Bakel,
37
M. van Beuzekom,
37
J. F. J. van den Brand,
75, 37
C. Van Den Broeck,
37, 193
D. C. Vander-Hyde,
42
L. van der Schaaf,
37
J. V. VanHeijningen,
66
A. A. van Veggel,
46
M. Vardaro,
53, 54
V. Varma,
48
S. Vass,
1
M. Vas ́uth,
50
A. Vecchio,
13
G. Vedovato,
54
J. Veitch,
46
P. J. Veitch,
57
K. Venkateswara,
179
G. Venugopalan,
1
D. Verkindt,
34
F. Vetrano,
63, 64
A. Vicer ́e,
63, 64
A. D. Viets,
24
S. Vinciguerra,
13
D. J. Vine,
133
J.-Y. Vinet,
65
S. Vitale,
14
T. Vo,
42
H. Vocca,
40, 41
C. Vorvick,
47
S. P. Vyatchanin,
61
A. R. Wade,
1
L. E. Wade,
122
M. Wade,
122
R. Walet,
37
M. Walker,
27
L. Wallace,
1
S. Walsh,
24
H. Wang,
13
J. Z. Wang,
138
S. Wang,
19
W. H. Wang,
109
Y. F. Wang,
94
R. L. Ward,
8
Z. A. Warden,
35
J. Warner,
47
M. Was,
34
J. Watchi,
103
B. Weaver,
47
L.-W. Wei,
9, 10
M. Weinert,
9, 10
A. J. Weinstein,
1
R. Weiss,
14
F. Wellmann,
9, 10
L. Wen,
66
E. K. Wessel,
19
P. Weßels,
9, 10
J. W. Westhouse,
35
K. Wette,
8
J. T. Whelan,
62
B. F. Whiting,
30
C. Whittle,
14
D. M. Wilken,
9, 10
D. Williams,
46
A. R. Williamson,
143, 37
J. L. Willis,
1
B. Willke,
10, 9
W. Winkler,
9, 10
C. C. Wipf,
1
H. Wittel,
9, 10
G. Woan,
46
J. Woehler,
9, 10
J. K. Wofford,
62
J. L. Wright,
46
D. S. Wu,
9, 10
D. M. Wysocki,
62
S. Xiao,
1
R. Xu,
110
H. Yamamoto,
1
C. C. Yancey,
77
L. Yang,
121
Y. Yang,
30
Z. Yang,
43
M. J. Yap,
8
M. Yazback,
30
D. W. Yeeles,
107
Hang Yu,
14
Haocun Yu,
14
S. H. R. Yuen,
94
A. K. Zadro ̇zny,
109
A. Zadro ̇zny,
157
M. Zanolin,
35
T. Zelenova,
29
J.-P. Zendri,
54
M. Zevin,
58
J. Zhang,
66
L. Zhang,
1
T. Zhang,
46
C. Zhao,
66
G. Zhao,
103
M. Zhou,
58
Z. Zhou,
58
X. J. Zhu,
6
A. B. Zimmerman,
194
M. E. Zucker,
1, 14
and J. Zweizig
1
(The LIGO Scientific Collaboration and the Virgo Collaboration)
S. Shandera
89
1
LIGO, California Institute of Technology, Pasadena, CA 91125, USA
2
Louisiana State University, Baton Rouge, LA 70803, USA
3
Inter-University Centre for Astronomy and Astrophysics, Pune 411007, India
4
Dipartimento di Farmacia, Universit`a di Salerno, I-84084 Fisciano, Salerno, Italy
5
INFN, Sezione di Napoli, Complesso Universitario di Monte S.Angelo, I-80126 Napoli, Italy
6
OzGrav, School of Physics & Astronomy, Monash University, Clayton 3800, Victoria, Australia
7
LIGO Livingston Observatory, Livingston, LA 70754, USA
8
OzGrav, Australian National University, Canberra, Australian Capital Territory 0200, Australia
9
Max Planck Institute for Gravitational Physics (Albert Einstein Institute), D-30167 Hannover, Germany
10
Leibniz Universit ̈at Hannover, D-30167 Hannover, Germany
11
Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universit ̈at Jena, D-07743 Jena, Germany
12
University of Cambridge, Cambridge CB2 1TN, United Kingdom
13
University of Birmingham, Birmingham B15 2TT, United Kingdom
14
LIGO, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
15
Instituto Nacional de Pesquisas Espaciais, 12227-010 S ̃ao Jos ́e dos Campos, S ̃ao Paulo, Brazil
16
Gran Sasso Science Institute (GSSI), I-67100 L’Aquila, Italy
17
INFN, Laboratori Nazionali del Gran Sasso, I-67100 Assergi, Italy
18
International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bengaluru 560089, India
19
NCSA, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
20
Universit`a di Pisa, I-56127 Pisa, Italy
21
INFN, Sezione di Pisa, I-56127 Pisa, Italy
22
Departamento de Astronom ́ıa y Astrof ́ısica, Universitat de Val`encia, E-46100 Burjassot, Val`encia, Spain
23
Laboratoire des Mat ́eriaux Avanc ́es (LMA), CNRS/IN2P3, F-69622 Villeurbanne, France
24
University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
25
SUPA, University of Strathclyde, Glasgow G1 1XQ, United Kingdom
11
26
APC, AstroParticule et Cosmologie, Universit ́e Paris Diderot,
CNRS/IN2P3, CEA/Irfu, Observatoire de Paris,
Sorbonne Paris Cit ́e, F-75205 Paris Cedex 13, France
27
California State University Fullerton, Fullerton, CA 92831, USA
28
LAL, Univ. Paris-Sud, CNRS/IN2P3, Universit ́e Paris-Saclay, F-91898 Orsay, France
29
European Gravitational Observatory (EGO), I-56021 Cascina, Pisa, Italy
30
University of Florida, Gainesville, FL 32611, USA
31
Chennai Mathematical Institute, Chennai 603103, India
32
INFN, Sezione di Roma Tor Vergata, I-00133 Roma, Italy
33
INFN, Sezione di Roma, I-00185 Roma, Italy
34
Laboratoire d’Annecy de Physique des Particules (LAPP), Univ. Grenoble Alpes,
Universit ́e Savoie Mont Blanc, CNRS/IN2P3, F-74941 Annecy, France
35
Embry-Riddle Aeronautical University, Prescott, AZ 86301, USA
36
Montclair State University, Montclair, NJ 07043, USA
37
Nikhef, Science Park 105, 1098 XG Amsterdam, The Netherlands
38
Korea Institute of Science and Technology Information, Daejeon 34141, South Korea
39
West Virginia University, Morgantown, WV 26506, USA
40
Universit`a di Perugia, I-06123 Perugia, Italy
41
INFN, Sezione di Perugia, I-06123 Perugia, Italy
42
Syracuse University, Syracuse, NY 13244, USA
43
University of Minnesota, Minneapolis, MN 55455, USA
44
Universit`a degli Studi di Milano-Bicocca, I-20126 Milano, Italy
45
INFN, Sezione di Milano-Bicocca, I-20126 Milano, Italy
46
SUPA, University of Glasgow, Glasgow G12 8QQ, United Kingdom
47
LIGO Hanford Observatory, Richland, WA 99352, USA
48
Caltech CaRT, Pasadena, CA 91125, USA
49
Dipartimento di Medicina, Chirurgia e Odontoiatria “Scuola Medica Salernitana,
” Universit`a di Salerno, I-84081 Baronissi, Salerno, Italy
50
Wigner RCP, RMKI, H-1121 Budapest, Konkoly Thege Mikl ́os ́ut 29-33, Hungary
51
Stanford University, Stanford, CA 94305, USA
52
Universit`a di Camerino, Dipartimento di Fisica, I-62032 Camerino, Italy
53
Universit`a di Padova, Dipartimento di Fisica e Astronomia, I-35131 Padova, Italy
54
INFN, Sezione di Padova, I-35131 Padova, Italy
55
Montana State University, Bozeman, MT 59717, USA
56
Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, 00-716, Warsaw, Poland
57
OzGrav, University of Adelaide, Adelaide, South Australia 5005, Australia
58
Center for Interdisciplinary Exploration & Research in Astrophysics (CIERA),
Northwestern University, Evanston, IL 60208, USA
59
INFN, Sezione di Genova, I-16146 Genova, Italy
60
RRCAT, Indore, Madhya Pradesh 452013, India
61
Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia
62
Rochester Institute of Technology, Rochester, NY 14623, USA
63
Universit`a degli Studi di Urbino “Carlo Bo,” I-61029 Urbino, Italy
64
INFN, Sezione di Firenze, I-50019 Sesto Fiorentino, Firenze, Italy
65
Artemis, Universit ́e Cˆote d’Azur, Observatoire Cˆote d’Azur,
CNRS, CS 34229, F-06304 Nice Cedex 4, France
66
OzGrav, University of Western Australia, Crawley, Western Australia 6009, Australia
67
Department of Astrophysics/IMAPP, Radboud University Nijmegen,
P.O. Box 9010, 6500 GL Nijmegen, The Netherlands
68
Dipartimento di Fisica “E.R. Caianiello,” Universit`a di Salerno, I-84084 Fisciano, Salerno, Italy
69
INFN, Sezione di Napoli, Gruppo Collegato di Salerno,
Complesso Universitario di Monte S. Angelo, I-80126 Napoli, Italy
70
Physik-Institut, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
71
Univ Rennes, CNRS, Institut FOTON - UMR6082, F-3500 Rennes, France
72
University of Oregon, Eugene, OR 97403, USA
73
Laboratoire Kastler Brossel, Sorbonne Universit ́e, CNRS,
ENS-Universit ́e PSL, Coll`ege de France, F-75005 Paris, France
74
Astronomical Observatory Warsaw University, 00-478 Warsaw, Poland
75
VU University Amsterdam, 1081 HV Amsterdam, The Netherlands
76
Max Planck Institute for Gravitational Physics (Albert Einstein Institute), D-14476 Potsdam-Golm, Germany
77
University of Maryland, College Park, MD 20742, USA
78
School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
79
Universit ́e de Lyon, Universit ́e Claude Bernard Lyon 1,
CNRS, Institut Lumi`ere Mati`ere, F-69622 Villeurbanne, France