GW170817: Implications for the Stochastic Gravitational-Wave
Background from Compact Binary Coalescences
B. P. Abbott et al.*
(LIGO Scientific Collaboration and Virgo Collaboration)
(Received 16 October 2017; revised manuscript received 16 January 2018; published 28 February 2018)
The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude
ΩGWðf¼25HzÞ¼1.8þ−12.7.3×10−9 with 90% confidence, compared withΩGWðf¼25HzÞ¼1.1þ−01.2.7×10−9
from binary black holes alone. Assuming the most probable rate for compact binary mergers, we find that the total background may be detectable with a signal-to-noise-ratio of 3 after 40 months of total observation time, based on the expected timeline for Advanced LIGO and Virgo to reach their design sensitivity.
DOI:10.1103/PhysRevLett.120.091101
Introduction.—On 17 August 2017, the Laser
Interferometer Gravitational-Wave Observatory (LIGO) [1] Scientific and Virgo [2] Collaborations detected a new gravitational-wave source: the coalescence of two neutron stars [3]. This event, GW170817, comes almost two years after GW150914, the first direct detection of gravitational waves from the merger of two black holes[4]. In total, six high confidence events detections and one sub-threshold candidate from binary black hole merger events have been reported: GW150914 [4], GW151226 [5], LVT151012 [6], GW170104 [7], GW170608 [8], and GW170814 [9]. The last of these events was reported as a three-detector observation by the two Advanced LIGO detectors located in Hanford, Washington, and Livingston, Louisiana, in the United States and the Advanced Virgo detector, located in Cascina, Italy.
In addition to loud and nearby events that are detectable as individual sources, there is also a population of unresolved events at greater distances. The superposition of these sources will contribute an astrophysical stochastic back-ground, which is discernible from detector noise by cross-correlating the data streams from two or more detectors [10,11]. For a survey of the expected signature of astro-physical backgrounds, see[12–18]. See also[19]for a recent review of data analysis tools for stochastic backgrounds.
Following the first detection of gravitational waves from GW150914, the LIGO and Virgo Collaborations calculated the expected stochastic background from a binary black hole (BBH) population with similar masses to the
components of GW150914[20]. These calculations were updated at the end of the first Advanced LIGO observing run (O1)[21]to take into account the two other black hole merger events observed during the run: GW151226, a high-confidence detection, and LVT151012, an event of lower significance. The results indicated that the background from black hole mergers would likely be detectable by Advanced LIGO and Advanced Virgo after a few years of their operation at design sensitivity. In the most optimistic case, a detection is possible even before instru-mental design sensitivity is reached.
In this Letter, we calculate the contribution to the background from a binary neutron star (BNS) population using the measured BNS merger rate derived from GW170817 [3]. We also update the previous predictions of the stochastic background from BBH mergers taking into account the most recent published statements about the rate of events[7]. We find the contributions to the back-ground from BBH and BNS mergers to be of similar magnitude. As a consequence, an astrophysical background (including contributions from BNS and BBH mergers) may be detected earlier than previously anticipated.
Background from compact binary mergers.—The
energy-density spectrum of a gravitational wave back-ground can be described by the dimensionless quantity
ΩGWðfÞ ¼ f
ρc dρGW
df ; ð1Þ
which represents the fractional contribution of gravitational waves to the critical energy density of the Universe[10]. HeredρGWis the energy density in the frequency intervalf
to fþdf, ρc¼3H20c2/ð8πGÞ is the critical energy density of the Universe, and the Hubble parameter H0¼ 67.90.55km s−1Mpc−1 is taken from Planck [22].
In order to model the background from all the binary mergers in the Universe, we follow a similar approach to [20]. A population of binary merger events may be characterized by a set of average source parametersθ(such as component masses or spins). If such a population merges at a rateRmðz;θÞper unit comoving volume per unit source
time at a given redshiftz, then the total gravitational-wave energy density spectrum from all the sources is given by (see, e.g.[12,20])
ΩGWðf;θÞ ¼ f
ρcH0 Z z
max
0 dz
Rmðz;θÞdEGWðfs;θÞ/dfs
ð1þzÞEðΩM;ΩΛ; zÞ :
ð2Þ
Here dEGWðfs;θÞ/dfs is the energy spectrum emitted
by a single source evaluated in terms of the source frequencyffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffifs¼ ð1þzÞf. The function EðΩM;ΩΛ; zÞ ¼
ΩMð1þzÞ3þΩΛ p
accounts for the dependence of comoving volume on redshift assuming the best-fit cos-mology from Planck[22], whereΩM¼1−ΩΛ¼0.3065. We choose to cut off the redshift integral at zmax¼10. Redshifts larger thanz¼5contribute little to the integral because of the½ð1þzÞEðzÞ−1factor in Eq.(2), as well as the small number of stars formed at such high redshift; see, for example, [12–18,23].
The energy spectrumdEGW/dfs is determined from the
strain waveform of the binary system. The dominant contribution to the background comes from the inspiral phase of the binary merger, for whichdE/dfs∝Mc5/3f−1/3,
whereMc¼ ðm1m2Þ3/5/ðm1þm2Þ1/5is the chirp mass for a binary system with component massesm1andm2. In the BNS case we only consider the inspiral phase, since neutron stars merge at ∼2kHz, well above the sensitive band of stochastic searches. We introduce a frequency cutoff at the innermost stable circular orbit. For BBH events, we include the merger and ringdown phases using the waveforms from [13,24]with the modifications from [25].
The merger rateRmðz;θÞis given by
Rmðz;θÞ ¼ Z t
max
tmin
Rfðzf;θÞpðtd;θÞdtd; ð3Þ
wheretdis the time delay between formation and merger of
a binary, pðtd;θÞ is the time delay distribution given
parameters θ, zf is the redshift at the formation time tf¼tðzÞ−td, andtðzÞis the age of the Universe at merger.
We assume that the binary formation rateRfðzf;θÞ scales
with the star formation rate. For the BNS background, we make similar assumptions to those used in[20], which are outlined in what follows below. We adopt the star formation
model of [26], which produces very similar results as compared to the model described by [27]. We assume a time delay distribution pðtdÞ∝1/td, for tmin< td< tmax. Here tmin is the minimum delay time between the binary formation and merger. We assumetmin¼20Myr[28]. The maximum time delaytmaxis set to the Hubble time[29–37]. We also need to consider the distribution of the component masses to calculate ΩGW. We assume that each mass is drawn from uniform distribution ranging from 1 to2M⊙.
The value of Rm at z¼0 is normalized to the median
BNS merger rate implied by GW170817, which is 1540þ3200
−1220 Gpc−3yr−1[3]. This rate is slightly higher than the realistic BNS merger rate predictions of[38], and those adopted in previous studies (e.g.[12,14]), but is consistent with optimistic predictions.
The calculation of the BBH background is similar, with the following differences. We assume tmin¼50 Myr for the minimum time delay[20,37]. Massive black holes are formed preferentially in low-metallicity environments. For binary systems with at least one black hole more massive than 30M⊙, we therefore reweight the star formation rateRfðzÞby the fraction of stars with
metal-licities Z≤Z⊙/2. Following [20], we adopt the mean
metallicity-redshift relation of [27], with appropriate scalings to account for local observations[26,39]. For a consistent computation, a mass distribution needs to be specified. We use a power-law distribution of the primary (i.e., larger mass) componentpðm1Þ∝m−2.35
1 and a uni-form distribution of the secondary[6,7]. In addition, we require that the component masses take values in the range 5–95M⊙ with m1þm2<100M⊙ and m2< m1, in agreement with the observations of BBHs to date [7]. For the rate of BBH mergers, we use the most recent published result associated with the power-law mass distribution 103þ−63110 Gpc−3yr−1 [7,40]. As shown in [21], using a flat-log mass distribution instead of the power-law only affects ΩGWðfÞ at frequencies above 100 Hz, which has very little impact on the detectability of the stochastic background with LIGO and Virgo. Frequencies below 100 Hz contribute to more than 99% of the sensitivity of the stochastic search[21].
The choices affecting the mass distribution have a minimal effect on the background energy density ΩGW in the low frequency part of the spectrum. We estimate the magnitude of the effect on the rateRusing the approximate scaling relationship R∼hVTi−1∼hM5/2
c i−1, where VT is
the sensitive spacetime volume of the instrument[41,42]. In the BBH case, for example, imposing a mass cutoff ofm1,
Predictions and detectability.—A stochastic background of gravitational waves introduces a correlated signal in networks of terrestrial detectors. This signal, expected to be much weaker than the detector noise, can be distinguished from noise by cross-correlating the strain data from two or more detectors. For a network ofndetectors, assuming an isotropic, unpolarized, Gaussian, and stationary back-ground, the optimal signal-to-noise ratio (SNR) of a cross-correlation search is given by
SNR¼ 3H 2 0 10π2
ffiffiffiffiffiffi
2T
p Z ∞
0 df
Xn
i¼1 X
j>i
γ2
ijðfÞΩ2GWðfÞ f6PiðfÞPjðfÞ
1/2 ;
ð4Þ
in which i,jrun over detector pairs, PiðfÞandPjðfÞare
the one-sided strain noise power spectral densities of the two detectors, andγijðfÞis the normalized isotropic over-lap reduction function between the pair[10,20]. While the cross-correlation search is not optimal for non-Gaussian backgrounds, Eq. (4) gives the correct expression for the cross-correlation signal-to-noise ratio irrespective of the Gaussianity of the background[28,43].
On the left-hand panel of Fig.1, we show the estimates on the background energy densityΩGWðfÞfor the BNS and BBH merger populations described in the previous section (red and green curves, respectively). The total (combined) background from BBH and BNS mergers is also plotted (solid blue curve) along with the 90% credible Poisson
uncertainties in the local rate (indicated by the grey shaded region). Considering this uncertainty, we predict
Ωtot
GWðf¼25HzÞ ¼1.8−þ12..37×10−9.
The spectrum is well approximated by a power law
ΩGWðfÞ∝f2/3 at low frequencies where the contribution from the inspiral phase is dominant. The power law remains a good approximation for f≲100Hz. Indeed, previous work suggests that the deviation from power-law behavior is probably inaccessible by advanced detectors [23]. The frequency region between 10 Hz and 100 Hz accounts for more than 99% of the accumulated SNR for the Advanced LIGO-Virgo network [21]. The median value of the background from BBH mergers½ΩBBHGWðf¼25HzÞ ¼ 1.1−þ01..72×10−9is comparable with our previous predictions [20]but the statistical uncertainty has decreased by a factor of 32% due to an increase in the number of observed BBH mergers. The median contribution from BNS systems is of the same order ½ΩGWBNSðf¼25HzÞ ¼0.7þ−01.5
.6×10−9. The statistical uncertainty of the BNS background is larger than that of the BBH background, since we have only one BNS detection. These results are summarized in TableI.
The estimates on the background energy density shown in Fig. 1 are compared with power-law integrated (PI) curves[45]at various observing sensitivities (O2, O3, and design). The PI curves represent the expected1σsensitivity of the standard cross-correlation search to power-law gravitational-wave backgrounds [45], for example, the
[image:3.612.73.552.424.609.2]ΩGWðfÞ∝f2/3 spectrum expected from the inspiral phase of binary mergers. Hence, if a power-law spectrum
intersects a PI curve, then it has SNR≥1 for the corre-sponding observing run.
Although the stochastic background is dominated by unresolvable sources, the energy-density spectra in Fig. 1
includecontributions from the loudest, individually detect-able events. Simulations of the astrophysical background given the inferred rate and mass distribution indicate that removing sources that are individually detectable by the LIGO-Virgo network with a combined SNR>12 has a very small impact on the results. The detectable sources have an even smaller effect than shown by the analysis in [20], which considered only the population of loud, high-mass sources. This highlights the fact that the spectrum is dominated by low-mass systems, which are less likely to be detected individually.
Different assumptions are possible on the various dis-tributions that enter the calculation ofΩGW[Eq.(2)], such as star formation rate, metallicity evolution, and delay times. However, we have verified that variations on our assumptions are contained within the Poisson band shown in Fig. 1, consistent with the detailed study in [20]. Additionally, if some of the observed BBH systems were of primordial (rather than stellar) origin, with a different redshift distribution, their contribution to the stochastic background spectrum could be weaker[46–48].
The right-hand panel of Fig. 1 shows the expected accumulated SNR as a function of total observation time, updated from [20]. For O1, which lasted approximately 4 months, we use the actual instrumental sensitivities of the two LIGO detectors (Virgo was not yet operating at that time) [21]. The second observing run (O2) was recently completed and ran for approximately 9 months. For this run we used typical sensitivities of 100 Mpc for Livingston and 60 Mpc for Hanford, assuming a duty cycle of 50%. We do not include Virgo as it does not contribute significantly to the sensitivity of stochastic searches in O2 due to the lower range and one-month integration time. For the next planned observing run (O3), and the following stages of sensitivity improvements, we include Virgo and assume a 50% duty cycle for each detector. Following[44], we assume O3 will be 12 months long (2017–2018). We define the “near
design”phase (2019+) to be a 12-month run where Hanford and Livingston operate at design sensitivity and Virgo at late sensitivity. Lastly, we assume that the“design”phase (2022+) will be 24 months and will have Hanford, Livingston, and Virgo operating at design sensitivity. These assumptions are broadly consistent with [44], although we make specific assumptions about the duration of each observing run for concreteness.
The median total background from a combined BBH and BNS background may be identified with SNR¼3, corre-sponding to false alarm probability <3×10−3, after approximately 40 months of observing. In the most optimistic scenario allowed by statistical uncertainties, the total background could be identified after 18 months or as early as O3. The most pessimistic case considered here is out of reach of the advanced detector network but is in the scope of third-generation detectors[49].
[image:4.612.318.557.47.238.2]Although the BNS and BBH backgrounds have similar energy densities, they have extremely different statistical properties. To illustrate this, we plot a simulated strain time series in Fig.2and show an example BNS (red) and BBH (green) background. The BNS events create an approx-imately continuous background consisting of a superposi-tion of overlapping sources, since the durasuperposi-tion of the
TABLE I. Estimates of the background energy densityΩGWðfÞ
at 25 Hz for each of the BNS, BBH, and total background contributions, along with the 90% Poisson error bounds. We also show the average timeτbetween events as seen by a detector in the frequency band above 10 Hz, and the number of overlapping sources at a given timeλ. We quote the number given the median rate and associated Poisson error bounds.
ΩGWð25HzÞ τ[s] λ
[image:4.612.50.298.134.196.2]BNS 0.7þ−1.50.6×10−9 13þ−949 15þ−1230 BBH 1.1þ−1.20.7×10−9 223þ−115352 0.06þ−00.06.04 Total 1.8þ−2.71.3×10−9 1244−8 15þ−1231
waveform (190 s on average in the frequency band above 10 Hz) is long compared to the average time interval between two successive events (13þ−949 s on average). Considering the uncertainty on the rate, the average number of overlapping sources can vary between 3 and 45. In Fig.2, 14 sources overlap on average.
The BBH background is different in nature even though the resulting energy density spectrum is similar. BBH events create a highly nonstationary and non-Gaussian background (sometimes referred to as a popcorn back-ground in the literature); i.e. individual events are well separated in time, on top of the continuous background from contributed BNS inspirals. The duration of the waveform is much smaller for these massive sources (14 s on average in the band above 10 Hz, considering both the power-law mass distribution and the distribution in redshift[49]) and much less than the time interval between events (223þ−115352s on average) resulting in rare overlaps.
TableIshows the estimated energy density at 25 Hz for each of the BNS, BBH, and total backgrounds. We also show the average time between eventsτ for each of these backgrounds as well as the average number of overlapping sources at any time λ, and the associated Poisson error bounds. The inverse of τ gives the rate of events in the Universe in s−1.
Conclusion.—The first gravitational wave detection of a binary neutron star system implies a significant contribu-tion to the stochastic gravitacontribu-tional-wave background from BNS mergers. Assuming the median merger rates, the background may be detected with SNR¼3after 40 months of accumulated observation time, during the design phase (2022+)[44]. In the most optimistic case, an astrophysical background may be observed at a level of 3σ after only 18 months of observation, during O3, the next observ-ing run.
There are additional factors which may lead to an even earlier detection. First, the presence of additional sources, for example, black hole-neutron star (BHNS) systems, will further add to the total background. Even small contributions to the background can decrease the time to detection. Previous estimates in the literature, for example [50,51], suggest that the BHNS will contribute roughly a few percent to the total background, although the uncertainty is large. Second, the analysis we have presented here assumes the standard cross-correlation search. Specialized non-Gaussian searches may be more sensitive, particularly to the BBH background [52–54]. Unlike a standard matched filter search, non-Gaussian pipelines do not attempt to find individual events, but rather to measure the rate of subthreshold events inde-pendently of their distribution.
A detection of the astrophysical background allows for a rich set of follow-up studies to fully understand its composition. The difference in the time-domain structure of the BBH and BNS signals may allow the BNS and BBH
backgrounds to be measured independently. After detecting the background, stochastic analyses can address whether the background is isotropic[55–57], unpolarized[58], and consistent with general relativity[59]. Finally, understand-ing the astrophysical background is crucial to subtract it and enable searches for a background of cosmological origin[49].
the Ministry of Science and Technology (MOST), Taiwan and the Kavli Foundation. The authors gratefully acknowl-edge the support of the NSF, STFC, MPS, INFN, CNRS and the State of Niedersachsen/Germany for provision of computational resources. This article has been assigned the document number LIGO-P1700272.
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B. P. Abbott,1R. Abbott,1T. D. Abbott,2F. Acernese,3,4K. Ackley,5,6C. Adams,7T. Adams,8P. Addesso,9R. X. Adhikari,1 V. B. Adya,10C. Affeldt,10M. Afrough,11B. Agarwal,12M. Agathos,13K. Agatsuma,14 N. Aggarwal,15O. D. Aguiar,16 L. Aiello,17,18A. Ain,19P. Ajith,20B. Allen,10,21,22G. Allen,12A. Allocca,23,24P. A. Altin,25A. Amato,26A. Ananyeva,1 S. B. Anderson,1 W. G. Anderson,21S. V. Angelova,27S. Antier,28S. Appert,1 K. Arai,1 M. C. Araya,1 J. S. Areeda,29
N. Arnaud,28,30 K. G. Arun,31S. Ascenzi,32,33 G. Ashton,10M. Ast,34S. M. Aston,7 P. Astone,35D. V. Atallah,36 P. Aufmuth,22C. Aulbert,10K. AultONeal,37C. Austin,2 A. Avila-Alvarez,29 S. Babak,38P. Bacon,39M. K. M. Bader,14 S. Bae,40P. T. Baker,41F. Baldaccini,42,43G. Ballardin,30S. W. Ballmer,44S. Banagiri,45J. C. Barayoga,1S. E. Barclay,46 B. C. Barish,1 D. Barker,47 K. Barkett,48F. Barone,3,4 B. Barr,46L. Barsotti,15M. Barsuglia,39D. Barta,49J. Bartlett,47 I. Bartos,50,5R. Bassiri,51A. Basti,23,24J. C. Batch,47M. Bawaj,52,43J. C. Bayley,46M. Bazzan,53,54B. B´ecsy,55C. Beer,10
M. Bejger,56I. Belahcene,28 A. S. Bell,46B. K. Berger,1 G. Bergmann,10J. J. Bero,57C. P. L. Berry,58D. Bersanetti,59 A. Bertolini,14 J. Betzwieser,7S. Bhagwat,44R. Bhandare,60I. A. Bilenko,61G. Billingsley,1 C. R. Billman,5 J. Birch,7 R. Birney,62O. Birnholtz,10S. Biscans,1,15S. Biscoveanu,63,6A. Bisht,22 M. Bitossi,30,24 C. Biwer,44M. A. Bizouard,28 J. K. Blackburn,1J. Blackman,48C. D. Blair,1,64D. G. Blair,64R. M. Blair,47S. Bloemen,65O. Bock,10N. Bode,10M. Boer,66 G. Bogaert,66A. Bohe,38F. Bondu,67E. Bonilla,51 R. Bonnand,8 B. A. Boom,14 R. Bork,1V. Boschi,30,24S. Bose,68,19
K. Bossie,7 Y. Bouffanais,39A. Bozzi,30C. Bradaschia,24P. R. Brady,21M. Branchesi,17,18J. E. Brau,69T. Briant,70 A. Brillet,66M. Brinkmann,10 V. Brisson,28P. Brockill,21 J. E. Broida,71A. F. Brooks,1 D. A. Brown,44 D. D. Brown,72
S. Brunett,1 C. C. Buchanan,2 A. Buikema,15T. Bulik,73H. J. Bulten,74,14 A. Buonanno,38,75D. Buskulic,8C. Buy,39 R. L. Byer,51M. Cabero,10L. Cadonati,76G. Cagnoli,26,77C. Cahillane,1 J. Calderón Bustillo,76T. A. Callister,1 E. Calloni,78,4J. B. Camp,79M. Canepa,80,59P. Canizares,65K. C. Cannon,81H. Cao,72J. Cao,82C. D. Capano,10 E. Capocasa,39F. Carbognani,30S. Caride,83 M. F. Carney,84 J. Casanueva Diaz,28C. Casentini,32,33 S. Caudill,21,14 M. Cavagli`a,11F. Cavalier,28R. Cavalieri,30G. Cella,24C. B. Cepeda,1P. Cerdá-Durán,85G. Cerretani,23,24E. Cesarini,86,33
S. J. Chamberlin,63M. Chan,46S. Chao,87P. Charlton,88E. Chase,89E. Chassande-Mottin,39 D. Chatterjee,21 B. D. Cheeseboro,41H. Y. Chen,90X. Chen,64Y. Chen,48H.-P. Cheng,5 H. Chia,5 A. Chincarini,59A. Chiummo,30
T. Chmiel,84H. S. Cho,91 M. Cho,75J. H. Chow,25N. Christensen,71,66 Q. Chu,64A. J. K. Chua,13S. Chua,70 A. K. W. Chung,92S. Chung,64G. Ciani,5,53,54R. Ciolfi,93,94C. E. Cirelli,51A. Cirone,80,59 F. Clara,47 J. A. Clark,76 P. Clearwater,95F. Cleva,66C. Cocchieri,11E. Coccia,17,18 P.-F. Cohadon,70D. Cohen,28A. Colla,96,35C. G. Collette,97
L. R. Cominsky,98M. Constancio Jr.,16L. Conti,54S. J. Cooper,58P. Corban,7 T. R. Corbitt,2 I. Cordero-Carrión,99 K. R. Corley,50N. Cornish,100A. Corsi,83S. Cortese,30C. A. Costa,16M. W. Coughlin,71,1S. B. Coughlin,89J.-P. Coulon,66 S. T. Countryman,50P. Couvares,1P. B. Covas,101E. E. Cowan,76D. M. Coward,64M. J. Cowart,7D. C. Coyne,1R. Coyne,83 J. D. E. Creighton,21T. D. Creighton,102J. Cripe,2 S. G. Crowder,103T. J. Cullen,29,2A. Cumming,46L. Cunningham,46
E. Cuoco,30 T. Dal Canton,79 G. Dálya,55 S. L. Danilishin,22,10S. D’Antonio,33K. Danzmann,22,10 A. Dasgupta,104 C. F. Da Silva Costa,5 V. Dattilo,30I. Dave,60M. Davier,28D. Davis,44E. J. Daw,105 B. Day,76 S. De,44D. DeBra,51
J. Degallaix,26M. De Laurentis,17,4S. Del´eglise,70W. Del Pozzo,58,23,24 N. Demos,15 T. Denker,10T. Dent,10 R. De Pietri,106,107V. Dergachev,38 R. De Rosa,78,4 R. T. DeRosa,7 C. De Rossi,26,30 R. DeSalvo,108 O. de Varona,10 J. Devenson,27S. Dhurandhar,19M. C. Díaz,102L. Di Fiore,4M. Di Giovanni,109,94T. Di Girolamo,50,78,4A. Di Lieto,23,24 S. Di Pace,96,35I. Di Palma,96,35F. Di Renzo,23,24Z. Doctor,90V. Dolique,26F. Donovan,15K. L. Dooley,11S. Doravari,10 I. Dorrington,36R. Douglas,46M. Dovale Álvarez,58T. P. Downes,21M. Drago,10C. Dreissigacker,10J. C. Driggers,47 Z. Du,82M. Ducrot,8P. Dupej,46S. E. Dwyer,47T. B. Edo,105M. C. Edwards,71A. Effler,7H.-B. Eggenstein,38,10P. Ehrens,1
E. J. Fauchon-Jones,36M. Favata,110M. Fays,36C. Fee,84H. Fehrmann,10J. Feicht,1M. M. Fejer,51A. Fernandez-Galiana,15 I. Ferrante,23,24E. C. Ferreira,16F. Ferrini,30 F. Fidecaro,23,24D. Finstad,44I. Fiori,30D. Fiorucci,39M. Fishbach,90
R. P. Fisher,44M. Fitz-Axen,45R. Flaminio,26,111 M. Fletcher,46H. Fong,112J. A. Font,85,113P. W. F. Forsyth,25 S. S. Forsyth,76J.-D. Fournier,66S. Frasca,96,35 F. Frasconi,24Z. Frei,55A. Freise,58R. Frey,69V. Frey,28E. M. Fries,1
P. Fritschel,15V. V. Frolov,7 P. Fulda,5M. Fyffe,7 H. Gabbard,46B. U. Gadre,19S. M. Gaebel,58J. R. Gair,114 L. Gammaitoni,42M. R. Ganija,72S. G. Gaonkar,19C. Garcia-Quiros,101F. Garufi,78,4B. Gateley,47S. Gaudio,37G. Gaur,115 V. Gayathri,116N. Gehrels,79,†G. Gemme,59E. Genin,30A. Gennai,24D. George,12J. George,60L. Gergely,117V. Germain,8 S. Ghonge,76Abhirup Ghosh,20Archisman Ghosh,20,14 S. Ghosh,65,14,21J. A. Giaime,2,7 K. D. Giardina,7 A. Giazotto,24 K. Gill,37L. Glover,108 E. Goetz,118R. Goetz,5 S. Gomes,36 B. Goncharov,6G. González,2 J. M. Gonzalez Castro,23,24 A. Gopakumar,119M. L. Gorodetsky,61S. E. Gossan,1M. Gosselin,30R. Gouaty,8A. Grado,120,4C. Graef,46M. Granata,26 A. Grant,46S. Gras,15C. Gray,47G. Greco,121,122A. C. Green,58E. M. Gretarsson,37P. Groot,65H. Grote,10S. Grunewald,38 P. Gruning,28G. M. Guidi,121,122X. Guo,82A. Gupta,63M. K. Gupta,104K. E. Gushwa,1E. K. Gustafson,1R. Gustafson,118 O. Halim,18,17B. R. Hall,68E. D. Hall,15E. Z. Hamilton,36 G. Hammond,46M. Haney,123 M. M. Hanke,10J. Hanks,47 C. Hanna,63M. D. Hannam,36O. A. Hannuksela,92J. Hanson,7T. Hardwick,2J. Harms,17,18G. M. Harry,124I. W. Harry,38
M. J. Hart,46C.-J. Haster,112 K. Haughian,46J. Healy,57A. Heidmann,70M. C. Heintze,7 H. Heitmann,66P. Hello,28 G. Hemming,30M. Hendry,46I. S. Heng,46J. Hennig,46A. W. Heptonstall,1 M. Heurs,10,22S. Hild,46T. Hinderer,65 D. Hoak,30D. Hofman,26 K. Holt,7 D. E. Holz,90P. Hopkins,36C. Horst,21J. Hough,46 E. A. Houston,46E. J. Howell,64 A. Hreibi,66Y. M. Hu,10E. A. Huerta,12D. Huet,28B. Hughey,37S. Husa,101S. H. Huttner,46T. Huynh-Dinh,7N. Indik,10 R. Inta,83G. Intini,96,35H. N. Isa,46J.-M. Isac,70M. Isi,1B. R. Iyer,20K. Izumi,47T. Jacqmin,70K. Jani,76P. Jaranowski,125 S. Jawahar,62F. Jim´enez-Forteza,101 W. W. Johnson,2 D. I. Jones,126R. Jones,46R. J. G. Jonker,14L. Ju,64J. Junker,10 C. V. Kalaghatgi,36V. Kalogera,89B. Kamai,1 S. Kandhasamy,7 G. Kang,40J. B. Kanner,1 S. J. Kapadia,21 S. Karki,69 K. S. Karvinen,10M. Kasprzack,2M. Katolik,12E. Katsavounidis,15W. Katzman,7S. Kaufer,22K. Kawabe,47F. K´ef´elian,66 D. Keitel,46A. J. Kemball,12R. Kennedy,105 C. Kent,36J. S. Key,127F. Y. Khalili,61 I. Khan,17,33S. Khan,10Z. Khan,104 E. A. Khazanov,128 N. Kijbunchoo,25Chunglee Kim,129 J. C. Kim,130 K. Kim,92W. Kim,72W. S. Kim,131Y.-M. Kim,91 S. J. Kimbrell,76E. J. King,72P. J. King,47M. Kinley-Hanlon,124R. Kirchhoff,10J. S. Kissel,47L. Kleybolte,34S. Klimenko,5 T. D. Knowles,41P. Koch,10S. M. Koehlenbeck,10S. Koley,14V. Kondrashov,1A. Kontos,15M. Korobko,34W. Z. Korth,1
I. Kowalska,73D. B. Kozak,1 C. Krämer,10V. Kringel,10B. Krishnan,10A. Królak,132,133G. Kuehn,10 P. Kumar,112 R. Kumar,104S. Kumar,20L. Kuo,87A. Kutynia,132S. Kwang,21B. D. Lackey,38K. H. Lai,92M. Landry,47R. N. Lang,134
J. Lange,57B. Lantz,51R. K. Lanza,15A. Lartaux-Vollard,28P. D. Lasky,6 M. Laxen,7 A. Lazzarini,1C. Lazzaro,54 P. Leaci,96,35S. Leavey,46C. H. Lee,91H. K. Lee,135H. M. Lee,136H. W. Lee,130K. Lee,46J. Lehmann,10A. Lenon,41
M. Leonardi,109,94N. Leroy,28N. Letendre,8 Y. Levin,6 T. G. F. Li,92S. D. Linker,108T. B. Littenberg,137J. Liu,64 R. K. L. Lo,92N. A. Lockerbie,62L. T. London,36J. E. Lord,44M. Lorenzini,17,18V. Loriette,138M. Lormand,7G. Losurdo,24
J. D. Lough,10C. O. Lousto,57G. Lovelace,29H. Lück,22,10 D. Lumaca,32,33 A. P. Lundgren,10R. Lynch,15 Y. Ma,48 R. Macas,36S. Macfoy,27B. Machenschalk,10M. MacInnis,15D. M. Macleod,36I. Magaña Hernandez,21 F. Magaña-Sandoval,44L. Magaña Zertuche,44R. M. Magee,63E. Majorana,35I. Maksimovic,138N. Man,66V. Mandic,45 V. Mangano,46G. L. Mansell,25M. Manske,21,25M. Mantovani,30F. Marchesoni,52,43F. Marion,8S. Márka,50Z. Márka,50
C. Markakis,12A. S. Markosyan,51 A. Markowitz,1 E. Maros,1A. Marquina,99F. Martelli,121,122L. Martellini,66 I. W. Martin,46R. M. Martin,110 D. V. Martynov,15 K. Mason,15E. Massera,105A. Masserot,8T. J. Massinger,1 M. Masso-Reid,46S. Mastrogiovanni,96,35A. Matas,45F. Matichard,1,15L. Matone,50N. Mavalvala,15N. Mazumder,68
R. McCarthy,47D. E. McClelland,25S. McCormick,7 L. McCuller,15 S. C. McGuire,139 G. McIntyre,1 J. McIver,1 D. J. McManus,25L. McNeill,6 T. McRae,25S. T. McWilliams,41D. Meacher,63G. D. Meadors,38,10M. Mehmet,10 J. Meidam,14E. Mejuto-Villa,9A. Melatos,95G. Mendell,47R. A. Mercer,21E. L. Merilh,47M. Merzougui,66S. Meshkov,1 C. Messenger,46C. Messick,63R. Metzdorff,70P. M. Meyers,45H. Miao,58C. Michel,26H. Middleton,58E. E. Mikhailov,140 L. Milano,78,4A. L. Miller,5,96,35B. B. Miller,89J. Miller,15M. Millhouse,100M. C. Milovich-Goff,108O. Minazzoli,66,141 Y. Minenkov,33J. Ming,38 C. Mishra,142S. Mitra,19 V. P. Mitrofanov,61G. Mitselmakher,5 R. Mittleman,15D. Moffa,84 A. Moggi,24K. Mogushi,11M. Mohan,30S. R. P. Mohapatra,15M. Montani,121,122C. J. Moore,13D. Moraru,47G. Moreno,47
I. Nardecchia,32,33 L. Naticchioni,96,35 R. K. Nayak,143J. Neilson,108G. Nelemans,65,14 T. J. N. Nelson,7 M. Nery,10 A. Neunzert,118L. Nevin,1J. M. Newport,124G. Newton,46,†K. K. Y. Ng,92T. T. Nguyen,25D. Nichols,65A. B. Nielsen,10 S. Nissanke,65,14A. Nitz,10A. Noack,10F. Nocera,30D. Nolting,7C. North,36L. K. Nuttall,36J. Oberling,47G. D. O’Dea,108 G. H. Ogin,144 J. J. Oh,131 S. H. Oh,131 F. Ohme,10M. A. Okada,16 M. Oliver,101P. Oppermann,10Richard J. Oram,7 B. O’Reilly,7R. Ormiston,45L. F. Ortega,5R. O’Shaughnessy,57S. Ossokine,38D. J. Ottaway,72H. Overmier,7B. J. Owen,83
A. E. Pace,63J. Page,137 M. A. Page,64 A. Pai,116,145S. A. Pai,60J. R. Palamos,69O. Palashov,128C. Palomba,35 A. Pal-Singh,34Howard Pan,87Huang-Wei Pan,87B. Pang,48P. T. H. Pang,92 C. Pankow,89 F. Pannarale,36 B. C. Pant,60
F. Paoletti,24A. Paoli,30M. A. Papa,38,21,10 A. Parida,19W. Parker,7 D. Pascucci,46A. Pasqualetti,30R. Passaquieti,23,24 D. Passuello,24M. Patil,133B. Patricelli,146,24B. L. Pearlstone,46M. Pedraza,1R. Pedurand,26,147L. Pekowsky,44A. Pele,7 S. Penn,148C. J. Perez,47A. Perreca,1,109,94L. M. Perri,89H. P. Pfeiffer,112,38 M. Phelps,46O. J. Piccinni,96,35 M. Pichot,66 F. Piergiovanni,121,122V. Pierro,9G. Pillant,30L. Pinard,26I. M. Pinto,9M. Pirello,47M. Pitkin,46M. Poe,21R. Poggiani,23,24
P. Popolizio,30E. K. Porter,39A. Post,10 J. Powell,46,149 J. Prasad,19 J. W. W. Pratt,37G. Pratten,101V. Predoi,36 T. Prestegard,21M. Prijatelj,10M. Principe,9S. Privitera,38G. A. Prodi,109,94L. G. Prokhorov,61O. Puncken,10M. Punturo,43
P. Puppo,35M. Pürrer,38H. Qi,21V. Quetschke,102 E. A. Quintero,1 R. Quitzow-James,69F. J. Raab,47D. S. Rabeling,25 H. Radkins,47 P. Raffai,55S. Raja,60C. Rajan,60B. Rajbhandari,83 M. Rakhmanov,102 K. E. Ramirez,102 A. Ramos-Buades,101 P. Rapagnani,96,35V. Raymond,38M. Razzano,23,24 J. Read,29T. Regimbau,66L. Rei,59S. Reid,62
D. H. Reitze,1,5 W. Ren,12S. D. Reyes,44F. Ricci,96,35 P. M. Ricker,12S. Rieger,10K. Riles,118M. Rizzo,57 N. A. Robertson,1,46R. Robie,46F. Robinet,28A. Rocchi,33L. Rolland,8 J. G. Rollins,1V. J. Roma,69J. D. Romano,102
R. Romano,3,4 C. L. Romel,47J. H. Romie,7 D. Rosińska,150,56 M. P. Ross,151 S. Rowan,46A. Rüdiger,10P. Ruggi,30 G. Rutins,27K. Ryan,47S. Sachdev,1 T. Sadecki,47L. Sadeghian,21M. Sakellariadou,152L. Salconi,30M. Saleem,116
F. Salemi,10 A. Samajdar,143 L. Sammut,6L. M. Sampson,89E. J. Sanchez,1L. E. Sanchez,1N. Sanchis-Gual,85 V. Sandberg,47J. R. Sanders,44 B. Sassolas,26B. S. Sathyaprakash,63,36P. R. Saulson,44O. Sauter,118R. L. Savage,47 A. Sawadsky,34P. Schale,69M. Scheel,48 J. Scheuer,89J. Schmidt,10P. Schmidt,1,65R. Schnabel,34R. M. S. Schofield,69
A. Schönbeck,34E. Schreiber,10 D. Schuette,10,22B. W. Schulte,10B. F. Schutz,36,10 S. G. Schwalbe,37J. Scott,46 S. M. Scott,25E. Seidel,12D. Sellers,7A. S. Sengupta,153D. Sentenac,30V. Sequino,32,33,17A. Sergeev,128D. A. Shaddock,25
T. J. Shaffer,47 A. A. Shah,137M. S. Shahriar,89M. B. Shaner,108L. Shao,38B. Shapiro,51P. Shawhan,75A. Sheperd,21 D. H. Shoemaker,15D. M. Shoemaker,76K. Siellez,76X. Siemens,21M. Sieniawska,56D. Sigg,47A. D. Silva,16
L. P. Singer,79 A. Singh,38,10,22A. Singhal,17,35A. M. Sintes,101B. J. J. Slagmolen,25B. Smith,7 J. R. Smith,29 R. J. E. Smith,1,6 S. Somala,154 E. J. Son,131 J. A. Sonnenberg,21B. Sorazu,46F. Sorrentino,59T. Souradeep,19 A. P. Spencer,46A. K. Srivastava,104K. Staats,37A. Staley,50 M. Steinke,10 J. Steinlechner,34,46 S. Steinlechner,34 D. Steinmeyer,10S. P. Stevenson,58,149R. Stone,102D. J. Stops,58K. A. Strain,46G. Stratta,121,122S. E. Strigin,61A. Strunk,47
R. Sturani,155A. L. Stuver,7 T. Z. Summerscales,156 L. Sun,95S. Sunil,104J. Suresh,19P. J. Sutton,36B. L. Swinkels,30 M. J. Szczepańczyk,37M. Tacca,14 S. C. Tait,46C. Talbot,6 D. Talukder,69 D. B. Tanner,5 M. Tápai,117A. Taracchini,38 J. D. Tasson,71J. A. Taylor,137R. Taylor,1S. V. Tewari,148T. Theeg,10F. Thies,10E. G. Thomas,58M. Thomas,7P. Thomas,47
K. A. Thorne,7 E. Thrane,6 S. Tiwari,17,94V. Tiwari,36K. V. Tokmakov,62 K. Toland,46M. Tonelli,23,24 Z. Tornasi,46 A. Torres-Forn´e,85C. I. Torrie,1D. Töyrä,58F. Travasso,30,43G. Traylor,7J. Trinastic,5M. C. Tringali,109,94L. Trozzo,157,24
K. W. Tsang,14M. Tse,15R. Tso,1 L. Tsukada,81D. Tsuna,81D. Tuyenbayev,102K. Ueno,21D. Ugolini,158 C. S. Unnikrishnan,119A. L. Urban,1S. A. Usman,36H. Vahlbruch,22G. Vajente,1 G. Valdes,2 N. van Bakel,14 M. van Beuzekom,14J. F. J. van den Brand,74,14 C. Van Den Broeck,14,159 D. C. Vander-Hyde,44L. van der Schaaf,14 J. V. van Heijningen,14A. A. van Veggel,46M. Vardaro,53,54V. Varma,48S. Vass,1M. Vasúth,49A. Vecchio,58G. Vedovato,54
J. Veitch,46P. J. Veitch,72 K. Venkateswara,151G. Venugopalan,1D. Verkindt,8 F. Vetrano,121,122A. Vicer´e,121,122 A. D. Viets,21S. Vinciguerra,58D. J. Vine,27J.-Y. Vinet,66S. Vitale,15T. Vo,44H. Vocca,42,43C. Vorvick,47 S. P. Vyatchanin,61A. R. Wade,1 L. E. Wade,84M. Wade,84R. Walet,14 M. Walker,29L. Wallace,1 S. Walsh,38,10,21 G. Wang,17,122 H. Wang,58J. Z. Wang,63W. H. Wang,102 Y. F. Wang,92R. L. Ward,25J. Warner,47M. Was,8 J. Watchi,97
B. Weaver,47L.-W. Wei,10,22 M. Weinert,10A. J. Weinstein,1R. Weiss,15L. Wen,64 E. K. Wessel,12 P. Weßels,10 J. Westerweck,10T. Westphal,10K. Wette,25J. T. Whelan,57B. F. Whiting,5 C. Whittle,6 D. Wilken,10D. Williams,46
D. M. Wysocki,57S. Xiao,1H. Yamamoto,1C. C. Yancey,75L. Yang,161M. J. Yap,25M. Yazback,5Hang Yu,15Haocun Yu,15 M. Yvert,8A. Zadrożny,132M. Zanolin,37T. Zelenova,30J.-P. Zendri,54M. Zevin,89L. Zhang,1M. Zhang,140T. Zhang,46
Y.-H. Zhang,57C. Zhao,64M. Zhou,89Z. Zhou,89S. J. Zhu,38,10X. J. Zhu,6 M. E. Zucker,1,15 and J. Zweizig1
(LIGO Scientific Collaboration and Virgo Collaboration)
1LIGO, California Institute of Technology, Pasadena, California 91125, USA 2
Louisiana State University, Baton Rouge, Louisiana 70803, USA 3Universit `a di Salerno, Fisciano, I-84084 Salerno, Italy 4
INFN, Sezione di Napoli, Complesso Universitario di Monte S.Angelo, I-80126 Napoli, Italy 5
University of Florida, Gainesville, Florida 32611, USA 6
OzGrav, School of Physics & Astronomy, Monash University, Clayton 3800, Victoria, Australia 7
LIGO Livingston Observatory, Livingston, Louisiana 70754, USA 8
Laboratoire d’Annecy-le-Vieux de Physique des Particules (LAPP), Universit´e Savoie Mont Blanc, CNRS/IN2P3, F-74941 Annecy, France
9
University of Sannio at Benevento, I-82100 Benevento, Italy and INFN, Sezione di Napoli, I-80100 Napoli, Italy 10
Max Planck Institute for Gravitational Physics (Albert Einstein Institute), D-30167 Hannover, Germany 11
The University of Mississippi, University, Mississippi 38677, USA 12
NCSA, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA 13
University of Cambridge, Cambridge CB2 1TN, United Kingdom 14
Nikhef, Science Park, 1098 XG Amsterdam, The Netherlands 15
LIGO, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA 16
Instituto Nacional de Pesquisas Espaciais, 12227-010 São Jos´e dos Campos, São Paulo, Brazil 17
Gran Sasso Science Institute (GSSI), I-67100 L’Aquila, Italy 18
INFN, Laboratori Nazionali del Gran Sasso, I-67100 Assergi, Italy 19
Inter-University Centre for Astronomy and Astrophysics, Pune 411007, India 20
International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bengaluru 560089, India 21
University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, USA 22Leibniz Universität Hannover, D-30167 Hannover, Germany
23
Universit `a di Pisa, I-56127 Pisa, Italy 24INFN, Sezione di Pisa, I-56127 Pisa, Italy 25
OzGrav, Australian National University, Canberra, Australian Capital Territory 0200, Australia 26Laboratoire des Mat´eriaux Avanc´es (LMA), CNRS/IN2P3, F-69622 Villeurbanne, France
27
SUPA, University of the West of Scotland, Paisley PA1 2BE, United Kingdom 28LAL, Univ. Paris-Sud, CNRS/IN2P3, Universit´e Paris-Saclay, F-91898 Orsay, France
29
California State University Fullerton, Fullerton, California 92831, USA 30European Gravitational Observatory (EGO), I-56021 Cascina, Pisa, Italy
31
Chennai Mathematical Institute, Chennai 603103, India 32Universit `a di Roma Tor Vergata, I-00133 Roma, Italy 33
INFN, Sezione di Roma Tor Vergata, I-00133 Roma, Italy 34Universität Hamburg, D-22761 Hamburg, Germany
35
INFN, Sezione di Roma, I-00185 Roma, Italy 36
Cardiff University, Cardiff CF24 3AA, United Kingdom 37
Embry-Riddle Aeronautical University, Prescott, Arizona 86301, USA 38
Max Planck Institute for Gravitational Physics (Albert Einstein Institute), D-14476 Potsdam-Golm, Germany 39
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 40
Korea Institute of Science and Technology Information, Daejeon 34141, Korea 41
West Virginia University, Morgantown, West Virginia 26506, USA 42
Universit`a di Perugia, I-06123 Perugia, Italy 43
INFN, Sezione di Perugia, I-06123 Perugia, Italy 44
Syracuse University, Syracuse, New York 13244, USA 45
University of Minnesota, Minneapolis, Minnesota 55455, USA 46
SUPA, University of Glasgow, Glasgow G12 8QQ, United Kingdom 47
LIGO Hanford Observatory, Richland, Washington 99352, USA 48
Caltech CaRT, Pasadena, California 91125, USA 49
Wigner RCP, RMKI, H-1121 Budapest, Konkoly Thege Miklós út 29-33, Hungary 50
Columbia University, New York, New York 10027, USA 51
52Universit `a di Camerino, Dipartimento di Fisica, I-62032 Camerino, Italy 53
Universit `a di Padova, Dipartimento di Fisica e Astronomia, I-35131 Padova, Italy 54INFN, Sezione di Padova, I-35131 Padova, Italy
55
Institute of Physics, Eötvös University, Pázmány P. s. 1/A, Budapest 1117, Hungary 56Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, 00-716 Warsaw, Poland
57
Rochester Institute of Technology, Rochester, New York 14623, USA 58University of Birmingham, Birmingham B15 2TT, United Kingdom
59
INFN, Sezione di Genova, I-16146 Genova, Italy 60RRCAT, Indore, Madhya Pradesh 452013, India 61
Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia 62SUPA, University of Strathclyde, Glasgow G1 1XQ, United Kingdom 63
The Pennsylvania State University, University Park, Pennsylvania 16802, USA 64OzGrav, University of Western Australia, Crawley, Western Australia 6009, Australia 65
Department of Astrophysics/IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands 66Artemis, Universit´e Côte d’Azur, Observatoire Côte d’Azur, CNRS, CS 34229, F-06304 Nice Cedex 4, France
67
Institut FOTON, CNRS, Universit´e de Rennes 1, F-35042 Rennes, France 68Washington State University, Pullman, Washington 99164, USA
69
University of Oregon, Eugene, Oregon 97403, USA
70Laboratoire Kastler Brossel, UPMC-Sorbonne Universit´es, CNRS, ENS-PSL Research University,
Coll`ege de France, F-75005 Paris, France 71Carleton College, Northfield, Minnesota 55057, USA 72
OzGrav, University of Adelaide, Adelaide, South Australia 5005, Australia 73Astronomical Observatory Warsaw University, 00-478 Warsaw, Poland
74
VU University Amsterdam, 1081 HV Amsterdam, The Netherlands 75University of Maryland, College Park, Maryland 20742, USA 76
Center for Relativistic Astrophysics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA 77Universit´e Claude Bernard Lyon 1, F-69622 Villeurbanne, France
78
Universit `a di Napoli ‘Federico II’, Complesso Universitario di Monte S.Angelo, I-80126 Napoli, Italy 79NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
80
Dipartimento di Fisica, Universit `a degli Studi di Genova, I-16146 Genova, Italy 81RESCEU, University of Tokyo, Tokyo 113-0033, Japan
82
Tsinghua University, Beijing 100084, China 83Texas Tech University, Lubbock, Texas 79409, USA
84
Kenyon College, Gambier, Ohio 43022, USA
85Departamento de Astronomía y Astrofísica, Universitat de Val`encia, E-46100 Burjassot, Val`encia, Spain 86
Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, I-00184 Roma, Italy 87National Tsing Hua University, Hsinchu City, 30013 Taiwan, Republic of China
88
Charles Sturt University, Wagga Wagga, New South Wales 2678, Australia
89Center for Interdisciplinary Exploration & Research in Astrophysics (CIERA), Northwestern University,
Evanston, Illinois 60208, USA
90University of Chicago, Chicago, Illinois 60637, USA 91
Pusan National University, Busan 46241, Korea 92The Chinese University of Hong Kong, Shatin, NT, Hong Kong 93
INAF, Osservatorio Astronomico di Padova, I-35122 Padova, Italy
94INFN, Trento Institute for Fundamental Physics and Applications, I-38123 Povo, Trento, Italy 95
OzGrav, University of Melbourne, Parkville, Victoria 3010, Australia 96Universit `a di Roma‘La Sapienza’, I-00185 Roma, Italy
97
Universit´e Libre de Bruxelles, Brussels 1050, Belgium 98Sonoma State University, Rohnert Park, California 94928, USA 99
Departamento de Matemáticas, Universitat de Val`encia, E-46100 Burjassot, Val`encia, Spain 100Montana State University, Bozeman, Montana 59717, USA
101
Universitat de les Illes Balears, IAC3—IEEC, E-07122 Palma de Mallorca, Spain 102The University of Texas Rio Grande Valley, Brownsville, Texas 78520, USA
103
Bellevue College, Bellevue, Washington 98007, USA 104Institute for Plasma Research, Bhat, Gandhinagar 382428, India
105
The University of Sheffield, Sheffield S10 2TN, United Kingdom
106Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Universit `a di Parma, I-43124 Parma, Italy 107
INFN, Sezione di Milano Bicocca, Gruppo Collegato di Parma, I-43124 Parma, Italy
108California State University, Los Angeles, 5151 State University Dr, Los Angeles, California 90032, USA 109
110Montclair State University, Montclair, New Jersey 07043, USA 111
National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan 112Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, Ontario M5S 3H8, Canada
113
Observatori Astronòmic, Universitat de Val`encia, E-46980 Paterna, Val`encia, Spain 114School of Mathematics, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom 115
University and Institute of Advanced Research, Koba Institutional Area, Gandhinagar, Gujarat 382007, India 116IISER-TVM, CET Campus, Trivandrum Kerala 695016, India
117
University of Szeged, Dóm t´er 9, Szeged 6720, Hungary 118University of Michigan, Ann Arbor, Michigan 48109, USA 119
Tata Institute of Fundamental Research, Mumbai 400005, India 120INAF, Osservatorio Astronomico di Capodimonte, I-80131 Napoli, Italy
121
Universit `a degli Studi di Urbino‘Carlo Bo’, I-61029 Urbino, Italy 122INFN, Sezione di Firenze, I-50019 Sesto Fiorentino, Firenze, Italy 123
Physik-Institut, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland 124American University, Washington, DC 20016, USA
125
University of Białystok, 15-424 Białystok, Poland
126University of Southampton, Southampton SO17 1BJ, United Kingdom 127
University of Washington Bothell, 18115 Campus Way NE, Bothell, Washington 98011, USA 128Institute of Applied Physics, Nizhny Novgorod 603950, Russia
129
Korea Astronomy and Space Science Institute, Daejeon 34055, Korea 130Inje University Gimhae, South Gyeongsang 50834, Korea 131
National Institute for Mathematical Sciences, Daejeon 34047, Korea 132NCBJ, 05-400Świerk-Otwock, Poland
133
Institute of Mathematics, Polish Academy of Sciences, 00656 Warsaw, Poland 134Hillsdale College, Hillsdale, Michigan 49242, USA
135
Hanyang University, Seoul 04763, Korea 136Seoul National University, Seoul 08826, Korea 137
NASA Marshall Space Flight Center, Huntsville, Alabama 35811, USA 138ESPCI, CNRS, F-75005 Paris, France
139
Southern University and A&M College, Baton Rouge, Louisiana 70813, USA 140College of William and Mary, Williamsburg, Virginia 23187, USA 141
Centre Scientifique de Monaco, 8 quai Antoine Ier, MC-98000, Monaco 142Indian Institute of Technology Madras, Chennai 600036, India
143
IISER-Kolkata, Mohanpur, West Bengal 741252, India
144Whitman College, 345 Boyer Avenue, Walla Walla, Washington 99362, USA 145
Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra 400076, India 146Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
147
Universit´e de Lyon, F-69361 Lyon, France
148Hobart and William Smith Colleges, Geneva, New York 14456, USA 149
OzGrav, Swinburne University of Technology, Hawthorn VIC 3122, Australia 150Janusz Gil Institute of Astronomy, University of Zielona Góra, 65-265 Zielona Góra, Poland
151
University of Washington, Seattle, Washington 98195, USA
152King’s College London, University of London, London WC2R 2LS, United Kingdom 153
Indian Institute of Technology, Gandhinagar Ahmedabad, Gujarat 382424, India 154Indian Institute of Technology Hyderabad, Sangareddy, Khandi, Telangana 502285, India 155
International Institute of Physics, Universidade Federal do Rio Grande do Norte, Natal RN 59078-970, Brazil 156Andrews University, Berrien Springs, Michigan 49104, USA
157
Universit `a di Siena, I-53100 Siena, Italy 158Trinity University, San Antonio, Texas 78212, USA 159
Van Swinderen Institute for Particle Physics and Gravity, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
160
Abilene Christian University, Abilene, Texas 79699, USA 161Colorado State University, Fort Collins, Colorado 80523, USA
