Search for intermediate mass black hole binaries in the first and second observing
runs of the Advanced LIGO and Virgo network
B. P. Abbott,
1
R. Abbott,
1
T. D. Abbott,
2
S. Abraham,
3
F. Acernese,
4, 5
K. Ackley,
6
A. Adams,
7
C. Adams,
8
R. X. Adhikari,
1
V. B. Adya,
9
C. Affeldt,
10, 11
M. Agathos,
12, 13
K. Agatsuma,
14
N. Aggarwal,
15
O. D. Aguiar,
16
L. Aiello,
17, 18
A. Ain,
3
P. Ajith,
19
G. Allen,
20
A. Allocca,
21, 22
M. A. Aloy,
23
P. A. Altin,
9
A. Amato,
24
S. Anand,
1
A. Ananyeva,
1
S. B. Anderson,
1
W. G. Anderson,
25
S. V. Angelova,
26
S. Antier,
27
S. Appert,
1
K. Arai,
1
M. C. Araya,
1
J. S. Areeda,
28
M. Ar`ene,
27
N. Arnaud,
29, 30
S. M. Aronson,
31
K. G. Arun,
32
S. Ascenzi,
17, 33
G. Ashton,
6
S. M. Aston,
8
P. Astone,
34
F. Aubin,
35
P. Aufmuth,
11
K. AultONeal,
36
C. Austin,
2
V. Avendano,
37
A. Avila-Alvarez,
28
S. Babak,
27
P. Bacon,
27
F. Badaracco,
17, 18
M. K. M. Bader,
38
S. Bae,
39
A. M. Baer,
7
J. Baird,
27
P. T. Baker,
40
F. Baldaccini,
41, 42
G. Ballardin,
30
S. W. Ballmer,
43
A. Bals,
36
S. Banagiri,
44
J. C. Barayoga,
1
C. Barbieri,
45, 46
S. E. Barclay,
47
B. C. Barish,
1
D. Barker,
48
K. Barkett,
49
S. Barnum,
15
F. Barone,
50, 5
B. Barr,
47
L. Barsotti,
15
M. Barsuglia,
27
D. Barta,
51
J. Bartlett,
48
I. Bartos,
31
R. Bassiri,
52
A. Basti,
21, 22
M. Bawaj,
53, 42
J. C. Bayley,
47
M. Bazzan,
54, 55
B. B ́ecsy,
56
M. Bejger,
27, 57
I. Belahcene,
29
A. S. Bell,
47
D. Beniwal,
58
M. G. Benjamin,
36
B. K. Berger,
52
G. Bergmann,
10, 11
S. Bernuzzi,
12
C. P. L. Berry,
59
D. Bersanetti,
60
A. Bertolini,
38
J. Betzwieser,
8
R. Bhandare,
61
J. Bidler,
28
E. Biggs,
25
I. A. Bilenko,
62
S. A. Bilgili,
40
G. Billingsley,
1
R. Birney,
26
O. Birnholtz,
63
S. Biscans,
1, 15
M. Bischi,
64, 65
S. Biscoveanu,
15
A. Bisht,
11
M. Bitossi,
30, 22
M. A. Bizouard,
66
J. K. Blackburn,
1
J. Blackman,
49
C. D. Blair,
8
D. G. Blair,
67
R. M. Blair,
48
S. Bloemen,
68
F. Bobba,
69, 70
N. Bode,
10, 11
M. Boer,
66
Y. Boetzel,
71
G. Bogaert,
66
F. Bondu,
72
R. Bonnand,
35
P. Booker,
10, 11
B. A. Boom,
38
R. Bork,
1
V. Boschi,
30
S. Bose,
3
V. Bossilkov,
67
J. Bosveld,
67
Y. Bouffanais,
54, 55
A. Bozzi,
30
C. Bradaschia,
22
P. R. Brady,
25
A. Bramley,
8
M. Branchesi,
17, 18
J. E. Brau,
73
M. Breschi,
12
T. Briant,
74
J. H. Briggs,
47
F. Brighenti,
64, 65
A. Brillet,
66
M. Brinkmann,
10, 11
P. Brockill,
25
A. F. Brooks,
1
J. Brooks,
30
D. D. Brown,
58
S. Brunett,
1
A. Buikema,
15
T. Bulik,
75
H. J. Bulten,
76, 38
A. Buonanno,
77, 78
D. Buskulic,
35
C. Buy,
27
R. L. Byer,
52
M. Cabero,
10, 11
L. Cadonati,
79
G. Cagnoli,
80
C. Cahillane,
1
J. Calder ́on Bustillo,
6
T. A. Callister,
1
E. Calloni,
81, 5
J. B. Camp,
82
W. A. Campbell,
6
M. Canepa,
83, 60
K. C. Cannon,
84
H. Cao,
58
J. Cao,
85
G. Carapella,
69, 70
F. Carbognani,
30
S. Caride,
86
M. F. Carney,
59
G. Carullo,
21, 22
J. Casanueva Diaz,
22
C. Casentini,
87, 33
S. Caudill,
38
M. Cavagli`a,
88, 89
F. Cavalier,
29
R. Cavalieri,
30
G. Cella,
22
P. Cerd ́a-Dur ́an,
23
E. Cesarini,
90, 33
O. Chaibi,
66
K. Chakravarti,
3
S. J. Chamberlin,
91
M. Chan,
47
S. Chao,
92
P. Charlton,
93
E. A. Chase,
59
E. Chassande-Mottin,
27
D. Chatterjee,
25
M. Chaturvedi,
61
B. D. Cheeseboro,
40
H. Y. Chen,
94
X. Chen,
67
Y. Chen,
49
H.-P. Cheng,
31
C. K. Cheong,
95
H. Y. Chia,
31
F. Chiadini,
96, 70
A. Chincarini,
60
A. Chiummo,
30
G. Cho,
97
H. S. Cho,
98
M. Cho,
78
N. Christensen,
99, 66
Q. Chu,
67
S. Chua,
74
K. W. Chung,
95
S. Chung,
67
G. Ciani,
54, 55
M. Cie ́slar,
57
A. A. Ciobanu,
58
R. Ciolfi,
100, 55
F. Cipriano,
66
A. Cirone,
83, 60
F. Clara,
48
J. A. Clark,
79
P. Clearwater,
101
F. Cleva,
66
E. Coccia,
17, 18
P.-F. Cohadon,
74
D. Cohen,
29
M. Colleoni,
102
C. G. Collette,
103
C. Collins,
14
M. Colpi,
45, 46
L. R. Cominsky,
104
M. Constancio Jr.,
16
L. Conti,
55
S. J. Cooper,
14
P. Corban,
8
T. R. Corbitt,
2
I. Cordero-Carri ́on,
105
S. Corezzi,
41, 42
K. R. Corley,
106
N. Cornish,
56
D. Corre,
29
A. Corsi,
86
S. Cortese,
30
C. A. Costa,
16
R. Cotesta,
77
M. W. Coughlin,
1
S. B. Coughlin,
107, 59
J.-P. Coulon,
66
S. T. Countryman,
106
P. Couvares,
1
P. B. Covas,
102
E. E. Cowan,
79
D. M. Coward,
67
M. J. Cowart,
8
D. C. Coyne,
1
R. Coyne,
108
J. D. E. Creighton,
25
T. D. Creighton,
109
J. Cripe,
2
M. Croquette,
74
S. G. Crowder,
110
T. J. Cullen,
2
A. Cumming,
47
L. Cunningham,
47
E. Cuoco,
30
T. Dal Canton,
82
G. D ́alya,
111
B. D’Angelo,
83, 60
S. L. Danilishin,
10, 11
S. D’Antonio,
33
K. Danzmann,
11, 10
A. Dasgupta,
112
C. F. Da Silva Costa,
31
L. E. H. Datrier,
47
V. Dattilo,
30
I. Dave,
61
M. Davier,
29
D. Davis,
43
E. J. Daw,
113
D. DeBra,
52
M. Deenadayalan,
3
J. Degallaix,
24
M. De Laurentis,
81, 5
S. Del ́eglise,
74
W. Del Pozzo,
21, 22
L. M. DeMarchi,
59
N. Demos,
15
T. Dent,
114
R. De Pietri,
115, 116
R. De Rosa,
81, 5
C. De Rossi,
24, 30
R. DeSalvo,
117
O. de Varona,
10, 11
S. Dhurandhar,
3
M. C. D ́ıaz,
109
T. Dietrich,
38
L. Di Fiore,
5
C. DiFronzo,
14
C. Di Giorgio,
69, 70
F. Di Giovanni,
23
M. Di Giovanni,
118, 119
T. Di Girolamo,
81, 5
A. Di Lieto,
21, 22
B. Ding,
103
S. Di Pace,
120, 34
I. Di Palma,
120, 34
F. Di Renzo,
21, 22
A. K. Divakarla,
31
A. Dmitriev,
14
Z. Doctor,
94
F. Donovan,
15
K. L. Dooley,
107, 88
S. Doravari,
3
I. Dorrington,
107
T. P. Downes,
25
M. Drago,
17, 18
J. C. Driggers,
48
Z. Du,
85
J.-G. Ducoin,
29
P. Dupej,
47
O. Durante,
69, 70
S. E. Dwyer,
48
P. J. Easter,
6
G. Eddolls,
47
T. B. Edo,
113
A. Effler,
8
P. Ehrens,
1
J. Eichholz,
9
S. S. Eikenberry,
31
M. Eisenmann,
35
R. A. Eisenstein,
15
L. Errico,
81, 5
R. C. Essick,
94
H. Estelles,
102
D. Estevez,
35
Z. B. Etienne,
40
T. Etzel,
1
M. Evans,
15
T. M. Evans,
8
V. Fafone,
87, 33, 17
S. Fairhurst,
107
X. Fan,
85
S. Farinon,
60
B. Farr,
73
W. M. Farr,
14
E. J. Fauchon-Jones,
107
M. Favata,
37
M. Fays,
113
M. Fazio,
121
C. Fee,
122
J. Feicht,
1
M. M. Fejer,
52
F. Feng,
27
D. L. Ferguson,
79
A. Fernandez-Galiana,
15
I. Ferrante,
21, 22
E. C. Ferreira,
16
T. A. Ferreira,
16
F. Fidecaro,
21, 22
I. Fiori,
30
D. Fiorucci,
17, 18
M. Fishbach,
94
R. P. Fisher,
7
J. M. Fishner,
15
arXiv:1906.08000v2 [gr-qc] 2 Jul 2019
2
R. Fittipaldi,
123, 70
M. Fitz-Axen,
44
V. Fiumara,
124, 70
R. Flaminio,
35, 125
M. Fletcher,
47
E. Floden,
44
E. Flynn,
28
H. Fong,
84
J. A. Font,
23, 126
P. W. F. Forsyth,
9
J.-D. Fournier,
66
Francisco Hernandez Vivanco,
6
S. Frasca,
120, 34
F. Frasconi,
22
Z. Frei,
111
A. Freise,
14
R. Frey,
73
V. Frey,
29
P. Fritschel,
15
V. V. Frolov,
8
G. Fronz`e,
127
P. Fulda,
31
M. Fyffe,
8
H. A. Gabbard,
47
B. U. Gadre,
77
S. M. Gaebel,
14
J. R. Gair,
128
L. Gammaitoni,
41
S. G. Gaonkar,
3
C. Garc ́ıa-Quir ́os,
102
F. Garufi,
81, 5
B. Gateley,
48
S. Gaudio,
36
G. Gaur,
129
V. Gayathri,
130
G. Gemme,
60
E. Genin,
30
A. Gennai,
22
D. George,
20
J. George,
61
L. Gergely,
131
S. Ghonge,
79
Abhirup Ghosh,
77
Archisman Ghosh,
38
S. Ghosh,
25
B. Giacomazzo,
118, 119
J. A. Giaime,
2, 8
K. D. Giardina,
8
D. R. Gibson,
132
K. Gill,
106
L. Glover,
133
J. Gniesmer,
134
P. Godwin,
91
E. Goetz,
48
R. Goetz,
31
B. Goncharov,
6
G. Gonz ́alez,
2
J. M. Gonzalez Castro,
21, 22
A. Gopakumar,
135
S. E. Gossan,
1
M. Gosselin,
30, 21, 22
R. Gouaty,
35
B. Grace,
9
A. Grado,
136, 5
M. Granata,
24
A. Grant,
47
S. Gras,
15
P. Grassia,
1
C. Gray,
48
R. Gray,
47
G. Greco,
64, 65
A. C. Green,
31
R. Green,
107
E. M. Gretarsson,
36
A. Grimaldi,
118, 119
S. J. Grimm,
17, 18
P. Groot,
68
H. Grote,
107
S. Grunewald,
77
P. Gruning,
29
G. M. Guidi,
64, 65
H. K. Gulati,
112
Y. Guo,
38
A. Gupta,
91
Anchal Gupta,
1
P. Gupta,
38
E. K. Gustafson,
1
R. Gustafson,
137
L. Haegel,
102
O. Halim,
18, 17
B. R. Hall,
138
E. D. Hall,
15
E. Z. Hamilton,
107
G. Hammond,
47
M. Haney,
71
M. M. Hanke,
10, 11
J. Hanks,
48
C. Hanna,
91
M. D. Hannam,
107
O. A. Hannuksela,
95
T. J. Hansen,
36
J. Hanson,
8
T. Harder,
66
T. Hardwick,
2
K. Haris,
19
J. Harms,
17, 18
G. M. Harry,
139
I. W. Harry,
140
R. K. Hasskew,
8
C. J. Haster,
15
K. Haughian,
47
F. J. Hayes,
47
J. Healy,
63
A. Heidmann,
74
M. C. Heintze,
8
H. Heitmann,
66
F. Hellman,
141
P. Hello,
29
G. Hemming,
30
M. Hendry,
47
I. S. Heng,
47
J. Hennig,
10, 11
M. Heurs,
10, 11
S. Hild,
47
T. Hinderer,
142, 38, 143
S. Hochheim,
10, 11
D. Hofman,
24
A. M. Holgado,
20
N. A. Holland,
9
K. Holt,
8
D. E. Holz,
94
P. Hopkins,
107
C. Horst,
25
J. Hough,
47
E. J. Howell,
67
C. G. Hoy,
107
Y. Huang,
15
M. T. H ̈ubner,
6
E. A. Huerta,
20
D. Huet,
29
B. Hughey,
36
V. Hui,
35
S. Husa,
102
S. H. Huttner,
47
T. Huynh-Dinh,
8
B. Idzkowski,
75
A. Iess,
87, 33
H. Inchauspe,
31
C. Ingram,
58
R. Inta,
86
G. Intini,
120, 34
B. Irwin,
122
H. N. Isa,
47
J.-M. Isac,
74
M. Isi,
15
B. R. Iyer,
19
T. Jacqmin,
74
S. J. Jadhav,
144
K. Jani,
79
N. N. Janthalur,
144
P. Jaranowski,
145
D. Jariwala,
31
A. C. Jenkins,
146
J. Jiang,
31
G. R. Johns,
7
D. S. Johnson,
20
A. W. Jones,
14
D. I. Jones,
147
J. D. Jones,
48
R. Jones,
47
R. J. G. Jonker,
38
L. Ju,
67
J. Junker,
10, 11
C. V. Kalaghatgi,
107
V. Kalogera,
59
B. Kamai,
1
S. Kandhasamy,
3
G. Kang,
39
J. B. Kanner,
1
S. J. Kapadia,
25
S. Karki,
73
R. Kashyap,
19
M. Kasprzack,
1
S. Katsanevas,
30
E. Katsavounidis,
15
W. Katzman,
8
S. Kaufer,
11
K. Kawabe,
48
N. V. Keerthana,
3
F. K ́ef ́elian,
66
D. Keitel,
140
R. Kennedy,
113
J. S. Key,
148
F. Y. Khalili,
62
B. Khamesra,
79
I. Khan,
17, 33
S. Khan,
10, 11
E. A. Khazanov,
149
N. Khetan,
17, 18
M. Khursheed,
61
N. Kijbunchoo,
9
Chunglee Kim,
150
G. J. Kim,
79
J. C. Kim,
151
K. Kim,
95
W. Kim,
58
W. S. Kim,
152
Y.-M. Kim,
153
C. Kimball,
59
P. J. King,
48
M. Kinley-Hanlon,
47
R. Kirchhoff,
10, 11
J. S. Kissel,
48
L. Kleybolte,
134
J. H. Klika,
25
S. Klimenko,
31
T. D. Knowles,
40
P. Koch,
10, 11
S. M. Koehlenbeck,
10, 11
G. Koekoek,
38, 154
S. Koley,
38
V. Kondrashov,
1
A. Kontos,
155
N. Koper,
10, 11
M. Korobko,
134
W. Z. Korth,
1
M. Kovalam,
67
D. B. Kozak,
1
C. Kr ̈amer,
10, 11
V. Kringel,
10, 11
N. Krishnendu,
32
A. Kr ́olak,
156, 157
N. Krupinski,
25
G. Kuehn,
10, 11
A. Kumar,
144
P. Kumar,
158
Rahul Kumar,
48
Rakesh Kumar,
112
L. Kuo,
92
A. Kutynia,
156
S. Kwang,
25
B. D. Lackey,
77
D. Laghi,
21, 22
P. Laguna,
79
K. H. Lai,
95
T. L. Lam,
95
M. Landry,
48
B. B. Lane,
15
R. N. Lang,
159
J. Lange,
63
B. Lantz,
52
R. K. Lanza,
15
A. Lartaux-Vollard,
29
P. D. Lasky,
6
M. Laxen,
8
A. Lazzarini,
1
C. Lazzaro,
55
P. Leaci,
120, 34
S. Leavey,
10, 11
Y. K. Lecoeuche,
48
C. H. Lee,
98
H. K. Lee,
160
H. M. Lee,
161
H. W. Lee,
151
J. Lee,
97
K. Lee,
47
J. Lehmann,
10, 11
A. K. Lenon,
40
N. Leroy,
29
N. Letendre,
35
Y. Levin,
6
A. Li,
95
J. Li,
85
K. J. L. Li,
95
T. G. F. Li,
95
X. Li,
49
F. Lin,
6
F. Linde,
162, 38
S. D. Linker,
133
T. B. Littenberg,
163
J. Liu,
67
X. Liu,
25
M. Llorens-Monteagudo,
23
R. K. L. Lo,
95, 1
L. T. London,
15
A. Longo,
164, 165
M. Lorenzini,
17, 18
V. Loriette,
166
M. Lormand,
8
G. Losurdo,
22
J. D. Lough,
10, 11
C. O. Lousto,
63
G. Lovelace,
28
M. E. Lower,
167
H. L ̈uck,
11, 10
D. Lumaca,
87, 33
A. P. Lundgren,
140
R. Lynch,
15
Y. Ma,
49
R. Macas,
107
S. Macfoy,
26
M. MacInnis,
15
D. M. Macleod,
107
A. Macquet,
66
I. Maga ̃na Hernandez,
25
F. Maga ̃na-Sandoval,
31
R. M. Magee,
91
E. Majorana,
34
I. Maksimovic,
166
A. Malik,
61
N. Man,
66
V. Mandic,
44
V. Mangano,
47, 120, 34
G. L. Mansell,
48, 15
M. Manske,
25
M. Mantovani,
30
M. Mapelli,
54, 55
F. Marchesoni,
53, 42
F. Marion,
35
S. M ́arka,
106
Z. M ́arka,
106
C. Markakis,
20
A. S. Markosyan,
52
A. Markowitz,
1
E. Maros,
1
A. Marquina,
105
S. Marsat,
27
F. Martelli,
64, 65
I. W. Martin,
47
R. M. Martin,
37
V. Martinez,
80
D. V. Martynov,
14
H. Masalehdan,
134
K. Mason,
15
E. Massera,
113
A. Masserot,
35
T. J. Massinger,
1
M. Masso-Reid,
47
S. Mastrogiovanni,
27
A. Matas,
77
F. Matichard,
1, 15
L. Matone,
106
N. Mavalvala,
15
J. J. McCann,
67
R. McCarthy,
48
D. E. McClelland,
9
S. McCormick,
8
L. McCuller,
15
S. C. McGuire,
168
C. McIsaac,
140
J. McIver,
1
D. J. McManus,
9
T. McRae,
9
S. T. McWilliams,
40
D. Meacher,
25
G. D. Meadors,
6
M. Mehmet,
10, 11
A. K. Mehta,
19
J. Meidam,
38
E. Mejuto Villa,
117, 70
A. Melatos,
101
G. Mendell,
48
R. A. Mercer,
25
L. Mereni,
24
K. Merfeld,
73
E. L. Merilh,
48
M. Merzougui,
66
S. Meshkov,
1
C. Messenger,
47
C. Messick,
91
F. Messina,
45, 46
R. Metzdorff,
74
P. M. Meyers,
101
F. Meylahn,
10, 11
A. Miani,
118, 119
H. Miao,
14
C. Michel,
24
H. Middleton,
101
L. Milano,
81, 5
A. L. Miller,
31, 120, 34
M. Millhouse,
101
J. C. Mills,
107
3
M. C. Milovich-Goff,
133
O. Minazzoli,
66, 169
Y. Minenkov,
33
A. Mishkin,
31
C. Mishra,
170
T. Mistry,
113
S. Mitra,
3
V. P. Mitrofanov,
62
G. Mitselmakher,
31
R. Mittleman,
15
G. Mo,
99
D. Moffa,
122
K. Mogushi,
88
S. R. P. Mohapatra,
15
M. Molina-Ruiz,
141
M. Mondin,
133
M. Montani,
64, 65
C. J. Moore,
14
D. Moraru,
48
F. Morawski,
57
G. Moreno,
48
S. Morisaki,
84
B. Mours,
35
C. M. Mow-Lowry,
14
F. Muciaccia,
120, 34
Arunava Mukherjee,
10, 11
D. Mukherjee,
25
S. Mukherjee,
109
Subroto Mukherjee,
112
N. Mukund,
10, 11, 3
A. Mullavey,
8
J. Munch,
58
E. A. Mu ̃niz,
43
M. Muratore,
36
P. G. Murray,
47
A. Nagar,
90, 127, 171
I. Nardecchia,
87, 33
L. Naticchioni,
120, 34
R. K. Nayak,
172
B. F. Neil,
67
J. Neilson,
117, 70
G. Nelemans,
68, 38
T. J. N. Nelson,
8
M. Nery,
10, 11
A. Neunzert,
137
L. Nevin,
1
K. Y. Ng,
15
S. Ng,
58
C. Nguyen,
27
P. Nguyen,
73
D. Nichols,
142, 38
S. A. Nichols,
2
S. Nissanke,
142, 38
F. Nocera,
30
C. North,
107
L. K. Nuttall,
140
M. Obergaulinger,
23, 173
J. Oberling,
48
B. D. O’Brien,
31
G. Oganesyan,
17, 18
G. H. Ogin,
174
J. J. Oh,
152
S. H. Oh,
152
F. Ohme,
10, 11
H. Ohta,
84
M. A. Okada,
16
M. Oliver,
102
P. Oppermann,
10, 11
Richard J. Oram,
8
B. O’Reilly,
8
R. G. Ormiston,
44
L. F. Ortega,
31
R. O’Shaughnessy,
63
S. Ossokine,
77
D. J. Ottaway,
58
H. Overmier,
8
B. J. Owen,
86
A. E. Pace,
91
G. Pagano,
21, 22
M. A. Page,
67
G. Pagliaroli,
17, 18
A. Pai,
130
S. A. Pai,
61
J. R. Palamos,
73
O. Palashov,
149
C. Palomba,
34
H. Pan,
92
P. K. Panda,
144
P. T. H. Pang,
95, 38
C. Pankow,
59
F. Pannarale,
120, 34
B. C. Pant,
61
F. Paoletti,
22
A. Paoli,
30
A. Parida,
3
W. Parker,
8, 168
D. Pascucci,
47, 38
A. Pasqualetti,
30
R. Passaquieti,
21, 22
D. Passuello,
22
M. Patil,
157
B. Patricelli,
21, 22
E. Payne,
6
B. L. Pearlstone,
47
T. C. Pechsiri,
31
A. J. Pedersen,
43
M. Pedraza,
1
R. Pedurand,
24, 175
A. Pele,
8
S. Penn,
176
A. Perego,
118, 119
C. J. Perez,
48
C. P ́erigois,
35
A. Perreca,
118, 119
J. Petermann,
134
H. P. Pfeiffer,
77
M. Phelps,
10, 11
K. S. Phukon,
3
O. J. Piccinni,
120, 34
M. Pichot,
66
F. Piergiovanni,
64, 65
V. Pierro,
117, 70
G. Pillant,
30
L. Pinard,
24
I. M. Pinto,
117, 70, 90
M. Pirello,
48
M. Pitkin,
47
W. Plastino,
164, 165
R. Poggiani,
21, 22
D. Y. T. Pong,
95
S. Ponrathnam,
3
P. Popolizio,
30
E. K. Porter,
27
J. Powell,
167
A. K. Prajapati,
112
J. Prasad,
3
K. Prasai,
52
R. Prasanna,
144
G. Pratten,
102
T. Prestegard,
25
M. Principe,
117, 90, 70
G. A. Prodi,
118, 119
L. Prokhorov,
14
M. Punturo,
42
P. Puppo,
34
M. P ̈urrer,
77
H. Qi,
107
V. Quetschke,
109
P. J. Quinonez,
36
F. J. Raab,
48
G. Raaijmakers,
142, 38
H. Radkins,
48
N. Radulesco,
66
P. Raffai,
111
S. Raja,
61
C. Rajan,
61
B. Rajbhandari,
86
M. Rakhmanov,
109
K. E. Ramirez,
109
A. Ramos-Buades,
102
Javed Rana,
3
K. Rao,
59
P. Rapagnani,
120, 34
V. Raymond,
107
M. Razzano,
21, 22
J. Read,
28
T. Regimbau,
35
L. Rei,
60
S. Reid,
26
D. H. Reitze,
1, 31
P. Rettegno,
127, 177
F. Ricci,
120, 34
C. J. Richardson,
36
J. W. Richardson,
1
P. M. Ricker,
20
G. Riemenschneider,
177, 127
K. Riles,
137
M. Rizzo,
59
N. A. Robertson,
1, 47
F. Robinet,
29
A. Rocchi,
33
L. Rolland,
35
J. G. Rollins,
1
V. J. Roma,
73
M. Romanelli,
72
R. Romano,
4, 5
C. L. Romel,
48
J. H. Romie,
8
C. A. Rose,
25
D. Rose,
28
K. Rose,
122
D. Rosi ́nska,
75
S. G. Rosofsky,
20
M. P. Ross,
178
S. Rowan,
47
A. R ̈udiger,
10, 11,
∗
P. Ruggi,
30
G. Rutins,
132
K. Ryan,
48
S. Sachdev,
91
T. Sadecki,
48
M. Sakellariadou,
146
O. S. Salafia,
179, 45, 46
L. Salconi,
30
M. Saleem,
32
A. Samajdar,
38
L. Sammut,
6
E. J. Sanchez,
1
L. E. Sanchez,
1
N. Sanchis-Gual,
180
J. R. Sanders,
181
K. A. Santiago,
37
E. Santos,
66
N. Sarin,
6
B. Sassolas,
24
B. S. Sathyaprakash,
91, 107
O. Sauter,
137, 35
R. L. Savage,
48
P. Schale,
73
M. Scheel,
49
J. Scheuer,
59
P. Schmidt,
14, 68
R. Schnabel,
134
R. M. S. Schofield,
73
A. Sch ̈onbeck,
134
E. Schreiber,
10, 11
B. W. Schulte,
10, 11
B. F. Schutz,
107
J. Scott,
47
S. M. Scott,
9
E. Seidel,
20
D. Sellers,
8
A. S. Sengupta,
182
N. Sennett,
77
D. Sentenac,
30
V. Sequino,
60
A. Sergeev,
149
Y. Setyawati,
10, 11
D. A. Shaddock,
9
T. Shaffer,
48
M. S. Shahriar,
59
M. B. Shaner,
133
A. Sharma,
17, 18
P. Sharma,
61
P. Shawhan,
78
H. Shen,
20
R. Shink,
183
D. H. Shoemaker,
15
D. M. Shoemaker,
79
K. Shukla,
141
S. ShyamSundar,
61
K. Siellez,
79
M. Sieniawska,
57
D. Sigg,
48
L. P. Singer,
82
D. Singh,
91
N. Singh,
75
A. Singhal,
17, 34
A. M. Sintes,
102
S. Sitmukhambetov,
109
V. Skliris,
107
B. J. J. Slagmolen,
9
T. J. Slaven-Blair,
67
J. R. Smith,
28
R. J. E. Smith,
6
S. Somala,
184
E. J. Son,
152
S. Soni,
2
B. Sorazu,
47
F. Sorrentino,
60
T. Souradeep,
3
E. Sowell,
86
A. P. Spencer,
47
M. Spera,
54, 55
A. K. Srivastava,
112
V. Srivastava,
43
K. Staats,
59
C. Stachie,
66
M. Standke,
10, 11
D. A. Steer,
27
M. Steinke,
10, 11
J. Steinlechner,
134, 47
S. Steinlechner,
134
D. Steinmeyer,
10, 11
S. P. Stevenson,
167
D. Stocks,
52
G. Stolle-mcallister,
122
R. Stone,
109
D. J. Stops,
14
K. A. Strain,
47
G. Stratta,
185, 65
S. E. Strigin,
62
A. Strunk,
48
R. Sturani,
186
A. L. Stuver,
187
V. Sudhir,
15
T. Z. Summerscales,
188
L. Sun,
1
S. Sunil,
112
A. Sur,
57
J. Suresh,
84
P. J. Sutton,
107
B. L. Swinkels,
38
M. J. Szczepa ́nczyk,
36
M. Tacca,
38
S. C. Tait,
47
C. Talbot,
6
D. B. Tanner,
31
D. Tao,
1
M. T ́apai,
131
A. Tapia,
28
J. D. Tasson,
99
R. Taylor,
1
R. Tenorio,
102
L. Terkowski,
134
M. Thomas,
8
P. Thomas,
48
S. R. Thondapu,
61
K. A. Thorne,
8
E. Thrane,
6
Shubhanshu Tiwari,
118, 119
Srishti Tiwari,
135
V. Tiwari,
107
K. Toland,
47
M. Tonelli,
21, 22
Z. Tornasi,
47
A. Torres-Forn ́e,
189
C. I. Torrie,
1
D. T ̈oyr ̈a,
14
F. Travasso,
30, 42
G. Traylor,
8
M. C. Tringali,
75
A. Tripathee,
137
A. Trovato,
27
L. Trozzo,
190, 22
K. W. Tsang,
38
M. Tse,
15
R. Tso,
49
L. Tsukada,
84
D. Tsuna,
84
T. Tsutsui,
84
D. Tuyenbayev,
109
K. Ueno,
84
D. Ugolini,
191
C. S. Unnikrishnan,
135
A. L. Urban,
2
S. A. Usman,
94
H. Vahlbruch,
11
G. Vajente,
1
G. Valdes,
2
M. Valentini,
118, 119
N. van Bakel,
38
M. van Beuzekom,
38
J. F. J. van den Brand,
76, 38
C. Van Den Broeck,
38, 192
D. C. Vander-Hyde,
43
L. van der Schaaf,
38
J. V. VanHeijningen,
67
A. A. van Veggel,
47
M. Vardaro,
54, 55
V. Varma,
49
S. Vass,
1
M. Vas ́uth,
51
A. Vecchio,
14
G. Vedovato,
55
J. Veitch,
47
P. J. Veitch,
58
K. Venkateswara,
178
4
G. Venugopalan,
1
D. Verkindt,
35
F. Vetrano,
64, 65
A. Vicer ́e,
64, 65
A. D. Viets,
25
S. Vinciguerra,
14
D. J. Vine,
132
J.-Y. Vinet,
66
S. Vitale,
15
T. Vo,
43
H. Vocca,
41, 42
C. Vorvick,
48
S. P. Vyatchanin,
62
A. R. Wade,
1
L. E. Wade,
122
M. Wade,
122
R. Walet,
38
M. Walker,
28
L. Wallace,
1
S. Walsh,
25
H. Wang,
14
J. Z. Wang,
137
S. Wang,
20
W. H. Wang,
109
Y. F. Wang,
95
R. L. Ward,
9
Z. A. Warden,
36
J. Warner,
48
M. Was,
35
J. Watchi,
103
B. Weaver,
48
L.-W. Wei,
10, 11
M. Weinert,
10, 11
A. J. Weinstein,
1
R. Weiss,
15
F. Wellmann,
10, 11
L. Wen,
67
E. K. Wessel,
20
P. Weßels,
10, 11
J. W. Westhouse,
36
K. Wette,
9
J. T. Whelan,
63
B. F. Whiting,
31
C. Whittle,
15
D. M. Wilken,
10, 11
D. Williams,
47
A. R. Williamson,
142, 38
J. L. Willis,
1
B. Willke,
11, 10
W. Winkler,
10, 11
C. C. Wipf,
1
H. Wittel,
10, 11
G. Woan,
47
J. Woehler,
10, 11
J. K. Wofford,
63
J. L. Wright,
47
D. S. Wu,
10, 11
D. M. Wysocki,
63
S. Xiao,
1
R. Xu,
110
H. Yamamoto,
1
C. C. Yancey,
78
L. Yang,
121
Y. Yang,
31
Z. Yang,
44
M. J. Yap,
9
M. Yazback,
31
D. W. Yeeles,
107
A. Yoon,
7
Hang Yu,
15
Haocun Yu,
15
S. H. R. Yuen,
95
A. K. Zadro ̇zny,
109
A. Zadro ̇zny,
156
M. Zanolin,
36
T. Zelenova,
30
J.-P. Zendri,
55
M. Zevin,
59
J. Zhang,
67
L. Zhang,
1
T. Zhang,
47
C. Zhao,
67
G. Zhao,
103
M. Zhou,
59
Z. Zhou,
59
X. J. Zhu,
6
M. E. Zucker,
1, 15
J. Zweizig,
1
F. Salemi,
193
and M. A. Papa
194, 195, 193
(The LIGO Scientific Collaboration and the Virgo Collaboration)
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
Christopher Newport University, Newport News, VA 23606, USA
8
LIGO Livingston Observatory, Livingston, LA 70754, USA
9
OzGrav, Australian National University, Canberra, Australian Capital Territory 0200, Australia
10
Max Planck Institute for Gravitational Physics (Albert Einstein Institute), D-30167 Hannover, Germany
11
Leibniz Universit ̈at Hannover, D-30167 Hannover, Germany
12
Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universit ̈at Jena, D-07743 Jena, Germany
13
University of Cambridge, Cambridge CB2 1TN, United Kingdom
14
University of Birmingham, Birmingham B15 2TT, United Kingdom
15
LIGO, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
16
Instituto Nacional de Pesquisas Espaciais, 12227-010 S ̃ao Jos ́e dos Campos, S ̃ao 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
International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bengaluru 560089, India
20
NCSA, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
21
Universit`a di Pisa, I-56127 Pisa, Italy
22
INFN, Sezione di Pisa, I-56127 Pisa, Italy
23
Departamento de Astronom ́ıa y Astrof ́ısica, Universitat de Val`encia, E-46100 Burjassot, Val`encia, Spain
24
Laboratoire des Mat ́eriaux Avanc ́es (LMA), CNRS/IN2P3, F-69622 Villeurbanne, France
25
University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
26
SUPA, University of Strathclyde, Glasgow G1 1XQ, United Kingdom
27
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
28
California State University Fullerton, Fullerton, CA 92831, USA
29
LAL, Univ. Paris-Sud, CNRS/IN2P3, Universit ́e Paris-Saclay, F-91898 Orsay, France
30
European Gravitational Observatory (EGO), I-56021 Cascina, Pisa, Italy
31
University of Florida, Gainesville, FL 32611, USA
32
Chennai Mathematical Institute, Chennai 603103, India
33
INFN, Sezione di Roma Tor Vergata, I-00133 Roma, Italy
34
INFN, Sezione di Roma, I-00185 Roma, Italy
35
Laboratoire d’Annecy de Physique des Particules (LAPP), Univ. Grenoble Alpes,
Universit ́e Savoie Mont Blanc, CNRS/IN2P3, F-74941 Annecy, France
36
Embry-Riddle Aeronautical University, Prescott, AZ 86301, USA
37
Montclair State University, Montclair, NJ 07043, USA
38
Nikhef, Science Park 105, 1098 XG Amsterdam, The Netherlands
39
Korea Institute of Science and Technology Information, Daejeon 34141, South Korea
40
West Virginia University, Morgantown, WV 26506, USA
41
Universit`a di Perugia, I-06123 Perugia, Italy
42
INFN, Sezione di Perugia, I-06123 Perugia, Italy
43
Syracuse University, Syracuse, NY 13244, USA
44
University of Minnesota, Minneapolis, MN 55455, USA
45
Universit`a degli Studi di Milano-Bicocca, I-20126 Milano, Italy
5
46
INFN, Sezione di Milano-Bicocca, I-20126 Milano, Italy
47
SUPA, University of Glasgow, Glasgow G12 8QQ, United Kingdom
48
LIGO Hanford Observatory, Richland, WA 99352, USA
49
Caltech CaRT, Pasadena, CA 91125, USA
50
Dipartimento di Medicina, Chirurgia e Odontoiatria “Scuola Medica Salernitana,
” Universit`a di Salerno, I-84081 Baronissi, Salerno, Italy
51
Wigner RCP, RMKI, H-1121 Budapest, Konkoly Thege Mikl ́os ́ut 29-33, Hungary
52
Stanford University, Stanford, CA 94305, USA
53
Universit`a di Camerino, Dipartimento di Fisica, I-62032 Camerino, Italy
54
Universit`a di Padova, Dipartimento di Fisica e Astronomia, I-35131 Padova, Italy
55
INFN, Sezione di Padova, I-35131 Padova, Italy
56
Montana State University, Bozeman, MT 59717, USA
57
Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, 00-716, Warsaw, Poland
58
OzGrav, University of Adelaide, Adelaide, South Australia 5005, Australia
59
Center for Interdisciplinary Exploration & Research in Astrophysics (CIERA),
Northwestern University, Evanston, IL 60208, USA
60
INFN, Sezione di Genova, I-16146 Genova, Italy
61
RRCAT, Indore, Madhya Pradesh 452013, India
62
Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia
63
Rochester Institute of Technology, Rochester, NY 14623, USA
64
Universit`a degli Studi di Urbino “Carlo Bo,” I-61029 Urbino, Italy
65
INFN, Sezione di Firenze, I-50019 Sesto Fiorentino, Firenze, Italy
66
Artemis, Universit ́e Cˆote d’Azur, Observatoire Cˆote d’Azur,
CNRS, CS 34229, F-06304 Nice Cedex 4, France
67
OzGrav, University of Western Australia, Crawley, Western Australia 6009, Australia
68
Department of Astrophysics/IMAPP, Radboud University Nijmegen,
P.O. Box 9010, 6500 GL Nijmegen, The Netherlands
69
Dipartimento di Fisica “E.R. Caianiello,” Universit`a di Salerno, I-84084 Fisciano, Salerno, Italy
70
INFN, Sezione di Napoli, Gruppo Collegato di Salerno,
Complesso Universitario di Monte S. Angelo, I-80126 Napoli, Italy
71
Physik-Institut, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
72
Univ Rennes, CNRS, Institut FOTON - UMR6082, F-3500 Rennes, France
73
University of Oregon, Eugene, OR 97403, USA
74
Laboratoire Kastler Brossel, Sorbonne Universit ́e, CNRS,
ENS-Universit ́e PSL, Coll`ege de France, F-75005 Paris, France
75
Astronomical Observatory Warsaw University, 00-478 Warsaw, Poland
76
VU University Amsterdam, 1081 HV Amsterdam, The Netherlands
77
Max Planck Institute for Gravitational Physics (Albert Einstein Institute), D-14476 Potsdam-Golm, Germany
78
University of Maryland, College Park, MD 20742, USA
79
School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
80
Universit ́e de Lyon, Universit ́e Claude Bernard Lyon 1,
CNRS, Institut Lumi`ere Mati`ere, F-69622 Villeurbanne, France
81
Universit`a di Napoli “Federico II,” Complesso Universitario di Monte S.Angelo, I-80126 Napoli, Italy
82
NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
83
Dipartimento di Fisica, Universit`a degli Studi di Genova, I-16146 Genova, Italy
84
RESCEU, University of Tokyo, Tokyo, 113-0033, Japan.
85
Tsinghua University, Beijing 100084, China
86
Texas Tech University, Lubbock, TX 79409, USA
87
Universit`a di Roma Tor Vergata, I-00133 Roma, Italy
88
The University of Mississippi, University, MS 38677, USA
89
Missouri University of Science and Technology, Rolla, MO 65409, USA
90
Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi,” I-00184 Roma, Italy
91
The Pennsylvania State University, University Park, PA 16802, USA
92
National Tsing Hua University, Hsinchu City, 30013 Taiwan, Republic of China
93
Charles Sturt University, Wagga Wagga, New South Wales 2678, Australia
94
University of Chicago, Chicago, IL 60637, USA
95
The Chinese University of Hong Kong, Shatin, NT, Hong Kong
96
Dipartimento di Ingegneria Industriale (DIIN),
Universit`a di Salerno, I-84084 Fisciano, Salerno, Italy
97
Seoul National University, Seoul 08826, South Korea
98
Pusan National University, Busan 46241, South Korea
99
Carleton College, Northfield, MN 55057, USA
100
INAF, Osservatorio Astronomico di Padova, I-35122 Padova, Italy
101
OzGrav, University of Melbourne, Parkville, Victoria 3010, Australia
6
102
Universitat de les Illes Balears, IAC3—IEEC, E-07122 Palma de Mallorca, Spain
103
Universit ́e Libre de Bruxelles, Brussels 1050, Belgium
104
Sonoma State University, Rohnert Park, CA 94928, USA
105
Departamento de Matem ́aticas, Universitat de Val`encia, E-46100 Burjassot, Val`encia, Spain
106
Columbia University, New York, NY 10027, USA
107
Cardiff University, Cardiff CF24 3AA, United Kingdom
108
University of Rhode Island, Kingston, RI 02881, USA
109
The University of Texas Rio Grande Valley, Brownsville, TX 78520, USA
110
Bellevue College, Bellevue, WA 98007, USA
111
MTA-ELTE Astrophysics Research Group, Institute of Physics, E ̈otv ̈os University, Budapest 1117, Hungary
112
Institute for Plasma Research, Bhat, Gandhinagar 382428, India
113
The University of Sheffield, Sheffield S10 2TN, United Kingdom
114
IGFAE, Campus Sur, Universidade de Santiago de Compostela, 15782 Spain
115
Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Universit`a di Parma, I-43124 Parma, Italy
116
INFN, Sezione di Milano Bicocca, Gruppo Collegato di Parma, I-43124 Parma, Italy
117
Dipartimento di Ingegneria, Universit`a del Sannio, I-82100 Benevento, Italy
118
Universit`a di Trento, Dipartimento di Fisica, I-38123 Povo, Trento, Italy
119
INFN, Trento Institute for Fundamental Physics and Applications, I-38123 Povo, Trento, Italy
120
Universit`a di Roma “La Sapienza,” I-00185 Roma, Italy
121
Colorado State University, Fort Collins, CO 80523, USA
122
Kenyon College, Gambier, OH 43022, USA
123
CNR-SPIN, c/o Universit`a di Salerno, I-84084 Fisciano, Salerno, Italy
124
Scuola di Ingegneria, Universit`a della Basilicata, I-85100 Potenza, Italy
125
National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
126
Observatori Astron`omic, Universitat de Val`encia, E-46980 Paterna, Val`encia, Spain
127
INFN Sezione di Torino, I-10125 Torino, Italy
128
School of Mathematics, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
129
Institute Of Advanced Research, Gandhinagar 382426, India
130
Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
131
University of Szeged, D ́om t ́er 9, Szeged 6720, Hungary
132
SUPA, University of the West of Scotland, Paisley PA1 2BE, United Kingdom
133
California State University, Los Angeles, 5151 State University Dr, Los Angeles, CA 90032, USA
134
Universit ̈at Hamburg, D-22761 Hamburg, Germany
135
Tata Institute of Fundamental Research, Mumbai 400005, India
136
INAF, Osservatorio Astronomico di Capodimonte, I-80131 Napoli, Italy
137
University of Michigan, Ann Arbor, MI 48109, USA
138
Washington State University, Pullman, WA 99164, USA
139
American University, Washington, D.C. 20016, USA
140
University of Portsmouth, Portsmouth, PO1 3FX, United Kingdom
141
University of California, Berkeley, CA 94720, USA
142
GRAPPA, Anton Pannekoek Institute for Astronomy and Institute for High-Energy Physics,
University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
143
Delta Institute for Theoretical Physics, Science Park 904, 1090 GL Amsterdam, The Netherlands
144
Directorate of Construction, Services & Estate Management, Mumbai 400094 India
145
University of Bia lystok, 15-424 Bia lystok, Poland
146
King’s College London, University of London, London WC2R 2LS, United Kingdom
147
University of Southampton, Southampton SO17 1BJ, United Kingdom
148
University of Washington Bothell, Bothell, WA 98011, USA
149
Institute of Applied Physics, Nizhny Novgorod, 603950, Russia
150
Ewha Womans University, Seoul 03760, South Korea
151
Inje University Gimhae, South Gyeongsang 50834, South Korea
152
National Institute for Mathematical Sciences, Daejeon 34047, South Korea
153
Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea
154
Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
155
Bard College, 30 Campus Rd, Annandale-On-Hudson, NY 12504, USA
156
NCBJ, 05-400
́
Swierk-Otwock, Poland
157
Institute of Mathematics, Polish Academy of Sciences, 00656 Warsaw, Poland
158
Cornell University, Ithaca, NY 14850, USA
159
Hillsdale College, Hillsdale, MI 49242, USA
160
Hanyang University, Seoul 04763, South Korea
161
Korea Astronomy and Space Science Institute, Daejeon 34055, South Korea
162
Institute for High-Energy Physics, University of Amsterdam,
Science Park 904, 1098 XH Amsterdam, The Netherlands
163
NASA Marshall Space Flight Center, Huntsville, AL 35811, USA
7
164
Dipartimento di Matematica e Fisica, Universit`a degli Studi Roma Tre, I-00146 Roma, Italy
165
INFN, Sezione di Roma Tre, I-00146 Roma, Italy
166
ESPCI, CNRS, F-75005 Paris, France
167
OzGrav, Swinburne University of Technology, Hawthorn VIC 3122, Australia
168
Southern University and A&M College, Baton Rouge, LA 70813, USA
169
Centre Scientifique de Monaco, 8 quai Antoine Ier, MC-98000, Monaco
170
Indian Institute of Technology Madras, Chennai 600036, India
171
Institut des Hautes Etudes Scientifiques, F-91440 Bures-sur-Yvette, France
172
IISER-Kolkata, Mohanpur, West Bengal 741252, India
173
Institut f ̈ur Kernphysik, Theoriezentrum, 64289 Darmstadt, Germany
174
Whitman College, 345 Boyer Avenue, Walla Walla, WA 99362 USA
175
Universit ́e de Lyon, F-69361 Lyon, France
176
Hobart and William Smith Colleges, Geneva, NY 14456, USA
177
Dipartimento di Fisica, Universit`a degli Studi di Torino, I-10125 Torino, Italy
178
University of Washington, Seattle, WA 98195, USA
179
INAF, Osservatorio Astronomico di Brera sede di Merate, I-23807 Merate, Lecco, Italy
180
Centro de Astrof ́ısica e Gravita ̧c ̃ao (CENTRA),
Departamento de F ́ısica, Instituto Superior T ́ecnico,
Universidade de Lisboa, 1049-001 Lisboa, Portugal
181
Marquette University, 11420 W. Clybourn St., Milwaukee, WI 53233, USA
182
Indian Institute of Technology, Gandhinagar Ahmedabad Gujarat 382424, India
183
Universit ́e de Montr ́eal/Polytechnique, Montreal, Quebec H3T 1J4, Canada
184
Indian Institute of Technology Hyderabad, Sangareddy, Khandi, Telangana 502285, India
185
INAF, Osservatorio di Astrofisica e Scienza dello Spazio, I-40129 Bologna, Italy
186
International Institute of Physics, Universidade Federal do Rio Grande do Norte, Natal RN 59078-970, Brazil
187
Villanova University, 800 Lancaster Ave, Villanova, PA 19085, USA
188
Andrews University, Berrien Springs, MI 49104, USA
189
Max Planck Institute for Gravitationalphysik (Albert Einstein Institute), D-14476 Potsdam-Golm, Germany
190
Universit`a di Siena, I-53100 Siena, Italy
191
Trinity University, San Antonio, TX 78212, USA
192
Van Swinderen Institute for Particle Physics and Gravity,
University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
193
Max Planck Institute for Gravitational Physics (Albert Einstein Institute), D-30167 Hannover, Germany
194
Max Planck Institute for Gravitational Physics (Albert Einstein Institute), D-14476 Potsdam-Golm, Germany
195
University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
(Dated: July 3, 2019)
Gravitational wave astronomy has been firmly established with the detection of gravitational
waves from the merger of ten stellar mass binary black holes and a neutron star binary. This paper
reports on the all-sky search for gravitational waves from intermediate mass black hole binaries in
the first and second observing runs of the Advanced LIGO and Virgo network. The search uses
three independent algorithms: two based on matched filtering of the data with waveform templates
of gravitational wave signals from compact binaries, and a third, model-independent algorithm that
employs no signal model for the incoming signal. No intermediate mass black hole binary event
was detected in this search. Consequently, we place upper limits on the merger rate density for a
family of intermediate mass black hole binaries. In particular, we choose sources with total masses
M
=
m
1
+
m
2
∈
[120
,
800] M
and mass ratios
q
=
m
2
/m
1
∈
[0
.
1
,
1
.
0]. For the first time, this
calculation is done using numerical relativity waveforms (which include higher modes) as models of
the real emitted signal. We place a most stringent upper limit of 0
.
20 Gpc
−
3
yr
−
1
(in co-moving
units at the 90% confidence level) for equal-mass binaries with individual masses
m
1
,
2
= 100 M
and dimensionless spins
χ
1
,
2
= 0
.
8 aligned with the orbital angular momentum of the binary. This
improves by a factor of
∼
5 that reported after Advanced LIGO’s first observing run.
PACS numbers: 04.80.Nn, 07.05.Kf, 95.55.Ym
I. INTRODUCTION
The first two observing runs of Advanced LIGO and
Virgo (O1 and O2 respectively) have significantly en-
hanced our understanding of black hole (BH) binaries in
∗
Deceased, July 2018.
the universe. Gravitational waves (GWs) from 10 binary
black hole mergers with total mass between 18
.
6
+3
.
1
−
0
.
7
M
and 85
.
1
+15
.
6
−
10
.
9
M
were detected during these two ob-
serving runs [1–8]. These observations have revealed a
new population of heavy stellar mass BH components of
up to 50 M
, for which we had no earlier electromag-
netic observational evidence [8, 9]. This finding limit is
8
consistent with the formation of heavier BHs from core
collapse being prevented by a mechanism known as
pul-
sational pair-instability supernovae
(PISN) [10–13]. Ac-
cording to this idea, stars with helium core mass in the
range
∼
32
−
64
M
undergo pulsational pair instabil-
ity leaving behind remnants of
.
65
M
. Stars with he-
lium core mass in the range
∼
64
−
135
M
undergo pair
instability and leave no remnant, while stars with he-
lium mass
&
135
M
are thought to directly collapse to
intermediate-mass black holes.
Intermediate mass black holes (IMBHs) are BHs heav-
ier than stellar mass BHs but lighter than supermas-
sive black holes (SMBHs), which places them roughly
in the range of 10
2
−
10
5
M
[14, 15]. Currently there
is only indirect observational evidence. Observations in-
clude probing the mass of the central BH in galaxies as
well as massive star clusters with direct kinematical mea-
surements which has led to recent claims for the presence
of IMBHs [16–18]. Other observations come from the ex-
trapolation of several scaling relations between the mass
of the central SMBH and their host galaxies [19] to the
mass range of globular clusters [20, 21]. In this way, sev-
eral clusters have been found to be good candidates for
having IMBHs in their centers [22–24]. If present, IMBHs
would heat up the cores of these clusters, strongly influ-
encing the distribution of the stars in the cluster and
their dynamics, leaving a characteristic imprint in the
surface brightness profile, as well as in the mass-to-light
ratio [25]. Controversy exists regarding the interpreta-
tion of these observations, as some of them can also be
explained by a high concentration of stellar-mass BHs
or the presence of binaries[22–24, 26]. Empirical mass
scaling relations of quasi-periodic oscillations [27] in lu-
minous X-Ray sources have also provided evidence for
IMBH [28]. Finally, IMBHs have been proposed as can-
didates to explain ultra-luminous X-Ray (ULX) sources
in nearby galaxies, which are brighter than the accret-
ing X-ray sources with stellar mass BHs [29, 30]. How-
ever, neutron stars or stellar-mass black holes emitting
above their Eddington luminosity could also account for
such observations. In summary, no definitive evidence of
IMBHs has yet been obtained.
The possible astrophysical formation channels of
IMBHs remain uncertain. Proposed channels include the
direct collapse of massive first generation, low metallicity
Population III stars [31–34] and mergers of stellar mass
BHs in globular clusters [36] and multiple collisions of
stars in dense young star clusters [18, 35, 37–39], among
others [40]. Further, some astrophysical scenarios [14] in-
dicate that SMBHs in galactic centers might be formed
from hierarchical mergers of IMBHs [15, 41]. The di-
rect observation of IMBHs with gravitational waves could
strengthen the possible evolutionary link between stel-
lar mass BHs and SMBHs. Finally, observing an IMBH
population would help to understand details of the pul-
sational pair-instability supernovae mechanism.
The GW observation of a coalescing binary consist-
ing of at least one IMBH component or resulting in an
IMBH remnant, which we will term an IMBHB, could
provide the first definitive confirmation of the existence of
IMBHs. In fact, IMBHBs are the sources that would emit
the most gravitational-wave energy in the LIGO-Virgo
frequency band, potentially making them detectable to
distances (and redshifts) beyond that of any other LIGO-
Virgo source [42]. Even in the absence of a detection,
a search for IMBHBs provides stringent constraints on
their merger rate density, which has implications for po-
tential IMBHB and SMBH formation channels.
IMBHs are not only interesting from an astrophysi-
cal point of view, they are also excellent laboratories
to test general relativity in the strong field regime [43–
46]. Their large masses would lead to strong merger
and ringdown signals in the Advanced LIGO-Virgo fre-
quency band. Therefore, higher modes might be visible in
IMBHB signals because those modes are especially strong
in the merger and ringdown stages. The observation of
multimodal merger and ringdown signals is paramount
to understanding fundamental properties of general rela-
tivity, such as the no-hair theorem [47–50] and BH kick
measurements [51–53].
The first search for GWs from IMBHBs was carried out
in the data from initial LIGO and initial Virgo (2005-
2010) [54, 55]. Owing to the large masses of IMB-
HBs, such systems are expected to merge at low fre-
quencies where the initial detectors were less sensitive
due to the presence of several noise sources, such as
suspension noise, thermal noise and optical cavity con-
trol noise. As a result, the those detectors were sen-
sitive to only the merger and ringdown phases of the
IMBHB systems. Initial IMBHB analyses applied either
the model-independent time-frequency searches [56] or
ringdown searches. No IMBHB merger was detected in
these searches.
Because of the improved low-frequency sensitivities
of the Advanced LIGO and Advanced Virgo detec-
tors [57, 58], IMBHB signals are visible in band for a
longer period of time, which increases the effectiveness
of modeled searches that use more than just the ring-
down portion of an IMBHB’s waveform. Ref. [42] re-
ports results from a combined search for IMBHBs that
used two independent search algorithms: a matched-
filter analysis, called GstLAL [59–61], which uses the
inspiral, merger, and ringdown portions of the IMBHB
waveform and the model-independent analysis coherent
WaveBurst (cWB) [56]. No IMBHBs were found by
these searches, and upper limits on the merger rate den-
sity for 12 targeted IMBHB sources with total mass be-
tween 120 M
−
600 M
and mass ratios down to 1
/
10
were obtained. The most stringent upper limit on the
merger rate density from this combined analysis was
0
.
93 Gpc
−
3
yr
−
1
for binaries consisting of two 100 M
BHs with dimensionless spin magnitude 0
.
8 aligned with
the system’s orbital angular momentum.
All upper limits on the IMBHB merger rate reported
in past searches [42, 54, 55] were obtained using models
for the GW signal that include only the dominant radiat-
9
ing mode, namely (
`,m
) = (2
,
±
2), of the GW emission
[62]. However, it has been shown that higher modes con-
tribute more substantially to signals emitted by heavy
binaries. This impact increases as the system becomes
more asymmetric in mass [63, 64], as the spin of the BHs
becomes more negative [65, 66], and as the precession in
the binary becomes stronger [67]. As a consequence, the
omission of higher modes leads in general to more con-
servative upper limits on the IMBHB merger rate [68].
In this work, we improve on past studies in two distinct
ways. We use numerical relativity (NR) simulations with
higher modes to model GW signals from IMBHBs for
computing upper limit estimates. Additionally, our com-
bined analysis now includes the matched-filter search Py-
CBC [69, 70] in addition to GstLAL and cWB. Because
of these novelties, we have, in addition to analyzing the
O2 data set, reanalyzed the O1 data set and report here
combined upper limits for the O1 and O2 observing runs.
In this paper, we report upper limits on the merger rate
density of 17 targeted (non-precessing) IMBHB sources.
Our most stringent upper limit is 0
.
20 Gpc
−
3
yr
−
1
for
equal-mass binaries with component spins aligned with
the orbital angular momentum of the system and dimen-
sionless magnitudes
χ
1
,
2
= 0
.
8.
The rest of this paper is organized as follows. In Sec. II
we describe the data set, outline the individual search al-
gorithms that make up the combined search, and report
our search’s null detection of IMBHBs. In Sec. III we
describe the NR simulations that we use to compute up-
per limits on IMBHB merger rates report these for the
case of 17 IMBHB sources. We draw final conclusions in
Sec. IV.
II. IMBHB SEARCH IN O1 AND O2 DATA
A. Data Summary
This analysis was carried out using O1 and O2 data
sets from the two LIGO (Livingston and Hanford) de-
tectors and Virgo. We have used the final calibration,
which was produced after the conclusion of the run, in-
cluding compensation for frequency-dependent fluctua-
tions in the calibration [71–73]. Well identified sources
of noise have also been subtracted from the strain data
as explained in Refs. [73, 74]. The maximum calibration
uncertainty across the frequency band of [10-5,000] Hz for
the two LIGO detectors is
∼
10% in amplitude and
∼
5
degrees in phase for O1 and
∼
4% in amplitude and
∼
3
degrees in phase for O2 [7, 71]. For Virgo we consider an
uncertainty of 5
.
1% in amplitude and 2
.
3 degrees in phase
[73]. After removing data with significant instrumental
disturbance, we use 48
.
6 days and 118
.
0 days of joint
Hanford-Livingston data from the O1 and O2 observing
runs respectively. The Virgo detector joined the LIGO
detectors during the last
∼
15 days of O2, which provided
with an additional 4
.
0 days of coincident data with either
of Hanford-Virgo or Livingston-Virgo network. The data
from O1 and O2 was divided into 9 and 21 blocks respec-
tively with coincident time ranging from 4
.
7
−
7
.
0 days.
For more details, see Ref. [8].
B. Search algorithms
We combine the two matched-filter searches, namely
GstLAL [59–61, 75] and PyCBC [69, 70], and one model-
independent analysis, cWB [76], into a single IMBHB
search. The two model-based matched filtering analy-
ses use a bank of templates made of pre-computed com-
pact binary merger GW waveforms. Matched filter based
analyses are optimal to extract known signals from sta-
tionary, Gaussian noise [77]. However, the templates we
use are limited to non-eccentric, aligned-spin systems.
They contain only the dominant waveform mode of the
GW emission and omit higher modes [64, 78]. Addi-
tionally, Advanced LIGO and Virgo data are known to
contain a large number of short noise transients [79],
which can mimic short GW signals like those emitted by
IMBHBs. While matched-filter searches use several tech-
niques to discriminate between noisy transients and real
GW events [61, 80, 81], they are known to lose significant
efficiency when looking for short signals like those from
IMBHBs. Therefore, the IMBHB search is carried out
jointly with an analysis that can identify short-duration
GW signals without a model for the morphology of the
GW waveform. In this search, all three analyses use O1
and O2 Advanced LIGO data. However, because of the
incomparable sensitivities between the Advanced LIGO
detector and Advanced Virgo detector, only the GstLAL
analysis uses Virgo data, as is done in Ref. [8].
1. Modeled analyses
The matched-filter analyses GstLAL and PyCBC use
templates that span the parameter space of neutron stars,
stellar-mass BHs, and IMBHs. In this study, we use the
same two searches reported in Ref. [8] to calculate upper
limits on the merger rate density of IMBHBs.
The matched-filter signal-to-noise ratio (SNR) time se-
ries is computed for every template. Triggers are pro-
duced when the SNR time series surpasses a predeter-
mined threshold, where clusters of triggers are trimmed
by maximizing the SNR within small time windows. In
addition, a signal consistency veto [61, 81, 82] is calcu-
lated for each trigger. A list of GW candidates is con-
structed from triggers generated by common templates
that are coincident in time across more than one detec-
tor, where the coincidence window takes into account the
travel time between detectors. Next, a ranking statistic
is calculated for each candidate that estimates a likeli-
hood ratio that the candidate would be observed in the
presence of a GW compared to a pure-noise expectation.
10
Finally, a
p
-value
1
P
is determined by comparing the
value of its ranking statistic to that of triggers coming
from background noise in the data. A detailed descrip-
tion of the GstLAL and PyCBC pipelines can be found
in Refs. [59–61, 75] and [69, 70], respectively; addition-
ally, details outlining how candidates are ranked across
observing runs can be found in Ref. [8].
The GstLAL analysis uses the template bank described
in Ref. [83]. The region of this bank that overlaps the
IMBHB parameter space, which starts at a total mass
of 100 M
, reaches up to a total mass of 400 M
in
the detector frame and covers mass ratios in the range
of 1
/
98
< q <
1. The waveforms used are a reduced-
order-model of the SEOBNRv4 approximant [84]. The
spin of these templates are either aligned or anti-aligned
with the orbital angular momentum of the system with
dimensionless magnitudes less than 0.999.
The PyCBC analysis uses the template bank described
in Ref. [85]. The region of this bank that overlaps the
IMBHB parameter space reaches up to a total mass
of 500 M
in the detector frame, excluding templates
with duration below 0.15 s, and covers the range of
1
/
98
< q <
1. The waveforms used are also a reduced-
order-model of the SEOBNRv4 approximant, and the
aligned or anti-aligned dimensionless spin magnitudes are
less than 0.998.
2. Un-modeled analysis
Coherent WaveBurst (cWB) is the GW transient de-
tection algorithm designed to look for unmodeled short-
duration GW transients in the multi-detector data from
interferometric GW detector networks. Designed to oper-
ate without a specific waveform model, cWB identifies co-
incident excess power in the wavelet time-frequency rep-
resentations of the detector strain data [86], for signal fre-
quencies up to 1 kHz and durations up to a few seconds.
The search identifies events that are coherent in multiple
detectors and reconstructs the source sky location and
signal waveforms by using the constrained maximum like-
lihood method [76]. The cWB detection statistic is based
on the coherent energy
E
c
obtained by cross-correlating
the signal waveforms reconstructed in multiple detectors.
It is proportional to the network SNR and used to rank
the events found by cWB.
To improve the robustness of the algorithm against
non-stationary detector noise,
cWB uses signal-
independent vetoes, which reduce the high rate of the
initial excess power triggers. The primary veto cut is on
the network correlation coefficient
c
c
=
E
c
/
(
E
c
+
E
n
),
where
E
n
is the residual noise energy estimated after the
reconstructed signal is subtracted from the data. Typi-
cally, for a GW signal
c
c
≈
1 and for instrumental glitches
1
The probability that noise would produce a trigger at least as
significant as the observed candidate.
c
c
1. Therefore, candidate events with
c
c
<
0
.
7 are
rejected as potential glitches.
To improve the detection efficiency of IMBHBs as well
as to reduce the false alarm rates (FARs), the cWB anal-
ysis employs additional selection cuts based on the na-
ture of IMBHB signals. IMBHB signals have two distinct
features in the time-frequency representation. First, the
signal frequencies lie below 250 Hz. We use this to ex-
clude all the non-IMBHB events in the search, including
noise events. Secondly, the inspiral signal duration in
the detector band is relatively short, which leads to rel-
atively low SNR in the inspiral phase as compared to
the merger and ringdown phases. In the cWB frame-
work, chirp mass (
M
= (
m
1
m
2
)
3
/
5
M
−
1
/
5
) is estimated
using the frequency evolution of a signal’s inspiral. How-
ever, in the case of low SNRs, we cannot accurately es-
timate the chirp mass of the binary [87]; still, we use
this framework to introduce additional cuts on the es-
timated chirp mass to reject non-IMBHB signals. The
simulation studies show that IMBHB signals are recov-
ered with
|M|
>
10 M
which we use in this search
2
. We
apply this selection cut to reduce the noise background
when producing the candidate events.
For estimation of the statistical significance of the can-
didate event, each event is ranked against a sample of
background triggers obtained by repeating the analysis
on time-shifted data [1]. To exclude astrophysical events
from the background sample, the time shifts are selected
to be much longer (1 second or more) than the expected
signal time delay between the detectors. By using differ-
ent time shifts, a sample of background events equivalent
to approximately 500 years of background data is accu-
mulated for each of the 30 blocks of data. The cWB can-
didate events that survived the cWB selection criteria,
are assigned a FAR given by the rate of the correspond-
ing background events with the coherent network SNR
value larger than that of the candidate event.
C. Combined search
Each of our three algorithms produces its own list of
GW candidates, characterized by GPS time, FAR and
associated
p
-value
P
. These three lists are then com-
bined into a common single list of candidates. To avoid
counting candidates more than once, candidates within a
time window of 100 ms across different lists are assumed
to be the same. To account for the use of three search
algorithms, we apply a conservative trials factor of 3 and
assign each candidate a new
p
-value given by
̄
P
= 1
−
(1
−
P
min
)
3
,
(1)
2
Negative
M
values correspond to frequencies decreasing with
time, which could be due to the pixels corresponding to ringdown
part.