Comprehensive All-sky Search for Periodic Gravitational Waves in the Sixth Science
Run LIGO Data
B. P. Abbott,
1
R. Abbott,
1
T. D. Abbott,
2
M. R. Abernathy,
3
F. Acernese,
4
,
5
K. Ackley,
6
C. Adams,
7
T. Adams,
8
P. Addesso,
9
R. X. Adhikari,
1
V. B. Adya,
10
C. Affeldt,
10
M. Agathos,
11
K. Agatsuma,
11
N. Aggarwal,
12
O. D. Aguiar,
13
L. Aiello,
14
,
15
A. Ain,
16
P. Ajith,
17
B. Allen,
10
,
18
,
19
A. Allocca,
20
,
21
P. A. Altin,
22
S. B. Anderson,
1
W. G. Anderson,
18
K. Arai,
1
M. C. Araya,
1
C. C. Arceneaux,
23
J. S. Areeda,
24
N. Arnaud,
25
K. G. Arun,
26
S. Ascenzi,
27
,
15
G. Ashton,
28
M. Ast,
29
S. M. Aston,
7
P. Astone,
30
P. Aufmuth,
19
C. Aulbert,
10
S. Babak,
31
P. Bacon,
32
M. K. M. Bader,
11
P. T. Baker,
33
F. Baldaccini,
34
,
35
G. Ballardin,
36
S. W. Ballmer,
37
J. C. Barayoga,
1
S. E. Barclay,
38
B. C. Barish,
1
D. Barker,
39
F. Barone,
4
,
5
B. Barr,
38
L. Barsotti,
12
M. Barsuglia,
32
D. Barta,
40
J. Bartlett,
39
I. Bartos,
41
R. Bassiri,
42
A. Basti,
20
,
21
J. C. Batch,
39
C. Baune,
10
V. Bavigadda,
36
M. Bazzan,
43
,
44
M. Bejger,
45
A. S. Bell,
38
B. K. Berger,
1
G. Bergmann,
10
C. P. L. Berry,
46
D. Bersanetti,
47
,
48
A. Bertolini,
11
J. Betzwieser,
7
S. Bhagwat,
37
R. Bhandare,
49
I. A. Bilenko,
50
G. Billingsley,
1
J. Birch,
7
R. Birney,
51
S. Biscans,
12
A. Bisht,
10
,
19
M. Bitossi,
36
C. Biwer,
37
M. A. Bizouard,
25
J. K. Blackburn,
1
C. D. Blair,
52
D. G. Blair,
52
R. M. Blair,
39
S. Bloemen,
53
O. Bock,
10
M. Boer,
54
G. Bogaert,
54
C. Bogan,
10
A. Bohe,
31
C. Bond,
46
F. Bondu,
55
R. Bonnand,
8
B. A. Boom,
11
R. Bork,
1
V. Boschi,
20
,
21
S. Bose,
56
,
16
Y. Bouffanais,
32
A. Bozzi,
36
C. Bradaschia,
21
P. R. Brady,
18
V. B. Braginsky,
50
M. Branchesi,
57
,
58
J. E. Brau,
59
T. Briant,
60
A. Brillet,
54
M. Brinkmann,
10
V. Brisson,
25
P. Brockill,
18
J. E. Broida,
61
A. F. Brooks,
1
D. A. Brown,
37
D. D. Brown,
46
N. M. Brown,
12
S. Brunett,
1
C. C. Buchanan,
2
A. Buikema,
12
T. Bulik,
62
H. J. Bulten,
63
,
11
A. Buonanno,
31
,
64
D. Buskulic,
8
C. Buy,
32
R. L. Byer,
42
M. Cabero,
10
L. Cadonati,
65
G. Cagnoli,
66
,
67
C. Cahillane,
1
J. Calder ́on Bustillo,
65
T. Callister,
1
E. Calloni,
68
,
5
J. B. Camp,
69
K. C. Cannon,
70
J. Cao,
71
C. D. Capano,
10
E. Capocasa,
32
F. Carbognani,
36
S. Caride,
72
J. Casanueva Diaz,
25
C. Casentini,
27
,
15
S. Caudill,
18
M. Cavagli`a,
23
F. Cavalier,
25
R. Cavalieri,
36
G. Cella,
21
C. B. Cepeda,
1
L. Cerboni Baiardi,
57
,
58
G. Cerretani,
20
,
21
E. Cesarini,
27
,
15
M. Chan,
38
S. Chao,
73
P. Charlton,
74
E. Chassande-Mottin,
32
B. D. Cheeseboro,
75
H. Y. Chen,
76
Y. Chen,
77
C. Cheng,
73
A. Chincarini,
48
A. Chiummo,
36
H. S. Cho,
78
M. Cho,
64
J. H. Chow,
22
N. Christensen,
61
Q. Chu,
52
S. Chua,
60
S. Chung,
52
G. Ciani,
6
F. Clara,
39
J. A. Clark,
65
F. Cleva,
54
E. Coccia,
27
,
14
P.-F. Cohadon,
60
A. Colla,
79
,
30
C. G. Collette,
80
L. Cominsky,
81
M. Constancio Jr.,
13
A. Conte,
79
,
30
L. Conti,
44
D. Cook,
39
T. R. Corbitt,
2
N. Cornish,
33
A. Corsi,
72
S. Cortese,
36
C. A. Costa,
13
M. W. Coughlin,
61
S. B. Coughlin,
82
J.-P. Coulon,
54
S. T. Countryman,
41
P. Couvares,
1
E. E. Cowan,
65
D. M. Coward,
52
M. J. Cowart,
7
D. C. Coyne,
1
R. Coyne,
72
K. Craig,
38
J. D. E. Creighton,
18
T. Creighton,
87
J. Cripe,
2
S. G. Crowder,
83
A. Cumming,
38
L. Cunningham,
38
E. Cuoco,
36
T. Dal Canton,
10
S. L. Danilishin,
38
S. D’Antonio,
15
K. Danzmann,
19
,
10
N. S. Darman,
84
A. Dasgupta,
85
C. F. Da Silva Costa,
6
V. Dattilo,
36
I. Dave,
49
M. Davier,
25
G. S. Davies,
38
E. J. Daw,
86
R. Day,
36
S. De,
37
D. DeBra,
42
G. Debreczeni,
40
J. Degallaix,
66
M. De Laurentis,
68
,
5
S. Del ́eglise,
60
W. Del Pozzo,
46
T. Denker,
10
T. Dent,
10
V. Dergachev,
1
R. De Rosa,
68
,
5
R. T. DeRosa,
7
R. DeSalvo,
9
R. C. Devine,
75
S. Dhurandhar,
16
M. C. D ́ıaz,
87
L. Di Fiore,
5
M. Di Giovanni,
88
,
89
T. Di Girolamo,
68
,
5
A. Di Lieto,
20
,
21
S. Di Pace,
79
,
30
I. Di Palma,
31
,
79
,
30
A. Di Virgilio,
21
V. Dolique,
66
F. Donovan,
12
K. L. Dooley,
23
S. Doravari,
10
R. Douglas,
38
T. P. Downes,
18
M. Drago,
10
R. W. P. Drever,
1
J. C. Driggers,
39
M. Ducrot,
8
S. E. Dwyer,
39
T. B. Edo,
86
M. C. Edwards,
61
A. Effler,
7
H.-B. Eggenstein,
10
P. Ehrens,
1
J. Eichholz,
6
,
1
S. S. Eikenberry,
6
W. Engels,
77
R. C. Essick,
12
T. Etzel,
1
M. Evans,
12
T. M. Evans,
7
R. Everett,
90
M. Factourovich,
41
V. Fafone,
27
,
15
H. Fair,
37
S. Fairhurst,
91
X. Fan,
71
Q. Fang,
52
S. Farinon,
48
B. Farr,
76
W. M. Farr,
46
M. Favata,
92
M. Fays,
91
H. Fehrmann,
10
M. M. Fejer,
42
E. Fenyvesi,
93
I. Ferrante,
20
,
21
E. C. Ferreira,
13
F. Ferrini,
36
F. Fidecaro,
20
,
21
I. Fiori,
36
D. Fiorucci,
32
R. P. Fisher,
37
R. Flaminio,
66
,
94
M. Fletcher,
38
J.-D. Fournier,
54
S. Frasca,
79
,
30
F. Frasconi,
21
Z. Frei,
93
A. Freise,
46
R. Frey,
59
V. Frey,
25
P. Fritschel,
12
V. V. Frolov,
7
P. Fulda,
6
M. Fyffe,
7
H. A. G. Gabbard,
23
J. R. Gair,
95
L. Gammaitoni,
34
S. G. Gaonkar,
16
F. Garufi,
68
,
5
G. Gaur,
96
,
85
N. Gehrels,
69
G. Gemme,
48
P. Geng,
87
E. Genin,
36
A. Gennai,
21
J. George,
49
L. Gergely,
97
V. Germain,
8
Abhirup Ghosh,
17
Archisman Ghosh,
17
S. Ghosh,
53
,
11
J. A. Giaime,
2
,
7
K. D. Giardina,
7
A. Giazotto,
21
K. Gill,
98
A. Glaefke,
38
E. Goetz,
39
R. Goetz,
6
L. Gondan,
93
G. Gonz ́alez,
2
J. M. Gonzalez Castro,
20
,
21
A. Gopakumar,
99
N. A. Gordon,
38
M. L. Gorodetsky,
50
S. E. Gossan,
1
M. Gosselin,
36
R. Gouaty,
8
A. Grado,
100
,
5
C. Graef,
38
P. B. Graff,
64
M. Granata,
66
A. Grant,
38
S. Gras,
12
C. Gray,
39
G. Greco,
57
,
58
A. C. Green,
46
P. Groot,
53
H. Grote,
10
S. Grunewald,
31
G. M. Guidi,
57
,
58
X. Guo,
71
A. Gupta,
16
M. K. Gupta,
85
K. E. Gushwa,
1
E. K. Gustafson,
1
R. Gustafson,
101
J. J. Hacker,
24
B. R. Hall,
56
E. D. Hall,
1
G. Hammond,
38
M. Haney,
99
M. M. Hanke,
10
J. Hanks,
39
C. Hanna,
90
M. D. Hannam,
91
J. Hanson,
7
T. Hardwick,
2
J. Harms,
57
,
58
G. M. Harry,
3
I. W. Harry,
31
M. J. Hart,
38
M. T. Hartman,
6
C.-J. Haster,
46
K. Haughian,
38
A. Heidmann,
60
M. C. Heintze,
7
H. Heitmann,
54
P. Hello,
25
G. Hemming,
36
M. Hendry,
38
arXiv:1605.03233v2 [gr-qc] 9 Jul 2016
2
I. S. Heng,
38
J. Hennig,
38
J. Henry,
102
A. W. Heptonstall,
1
M. Heurs,
10
,
19
S. Hild,
38
D. Hoak,
36
D. Hofman,
66
K. Holt,
7
D. E. Holz,
76
P. Hopkins,
91
J. Hough,
38
E. A. Houston,
38
E. J. Howell,
52
Y. M. Hu,
10
S. Huang,
73
E. A. Huerta,
103
D. Huet,
25
B. Hughey,
98
S. Husa,
104
S. H. Huttner,
38
T. Huynh-Dinh,
7
N. Indik,
10
D. R. Ingram,
39
R. Inta,
72
H. N. Isa,
38
J.-M. Isac,
60
M. Isi,
1
T. Isogai,
12
B. R. Iyer,
17
K. Izumi,
39
T. Jacqmin,
60
H. Jang,
78
K. Jani,
65
P. Jaranowski,
105
S. Jawahar,
106
L. Jian,
52
F. Jim ́enez-Forteza,
104
W. W. Johnson,
2
D. I. Jones,
28
R. Jones,
38
R. J. G. Jonker,
11
L. Ju,
52
Haris K,
107
C. V. Kalaghatgi,
91
V. Kalogera,
82
S. Kandhasamy,
23
G. Kang,
78
J. B. Kanner,
1
S. J. Kapadia,
10
S. Karki,
59
K. S. Karvinen,
10
M. Kasprzack,
36
,
2
E. Katsavounidis,
12
W. Katzman,
7
S. Kaufer,
19
T. Kaur,
52
K. Kawabe,
39
F. K ́ef ́elian,
54
M. S. Kehl,
108
D. Keitel,
104
D. B. Kelley,
37
W. Kells,
1
R. Kennedy,
86
J. S. Key,
87
F. Y. Khalili,
50
I. Khan,
14
S. Khan,
91
Z. Khan,
85
E. A. Khazanov,
109
N. Kijbunchoo,
39
Chi-Woong Kim,
78
Chunglee Kim,
78
J. Kim,
110
K. Kim,
111
N. Kim,
42
W. Kim,
112
Y.-M. Kim,
110
S. J. Kimbrell,
65
E. J. King,
112
P. J. King,
39
J. S. Kissel,
39
B. Klein,
82
L. Kleybolte,
29
S. Klimenko,
6
S. M. Koehlenbeck,
10
S. Koley,
11
V. Kondrashov,
1
A. Kontos,
12
M. Korobko,
29
W. Z. Korth,
1
I. Kowalska,
62
D. B. Kozak,
1
V. Kringel,
10
B. Krishnan,
10
A. Kr ́olak,
113
,
114
C. Krueger,
19
G. Kuehn,
10
P. Kumar,
108
R. Kumar,
85
L. Kuo,
73
A. Kutynia,
113
B. D. Lackey,
37
M. Landry,
39
J. Lange,
102
B. Lantz,
42
P. D. Lasky,
115
M. Laxen,
7
A. Lazzarini,
1
C. Lazzaro,
44
P. Leaci,
79
,
30
S. Leavey,
38
E. O. Lebigot,
32
,
71
C. H. Lee,
110
H. K. Lee,
111
H. M. Lee,
116
K. Lee,
38
A. Lenon,
37
M. Leonardi,
88
,
89
J. R. Leong,
10
N. Leroy,
25
N. Letendre,
8
Y. Levin,
115
J. B. Lewis,
1
T. G. F. Li,
117
A. Libson,
12
T. B. Littenberg,
118
N. A. Lockerbie,
106
A. L. Lombardi,
119
L. T. London,
91
J. E. Lord,
37
M. Lorenzini,
14
,
15
V. Loriette,
120
M. Lormand,
7
G. Losurdo,
58
J. D. Lough,
10
,
19
H. L ̈uck,
19
,
10
A. P. Lundgren,
10
R. Lynch,
12
Y. Ma,
52
B. Machenschalk,
10
M. MacInnis,
12
D. M. Macleod,
2
F. Maga ̃na-Sandoval,
37
L. Maga ̃na Zertuche,
37
R. M. Magee,
56
E. Majorana,
30
I. Maksimovic,
120
V. Malvezzi,
27
,
15
N. Man,
54
I. Mandel,
46
V. Mandic,
83
V. Mangano,
38
G. L. Mansell,
22
M. Manske,
18
M. Mantovani,
36
F. Marchesoni,
121
,
35
F. Marion,
8
S. M ́arka,
41
Z. M ́arka,
41
A. S. Markosyan,
42
E. Maros,
1
F. Martelli,
57
,
58
L. Martellini,
54
I. W. Martin,
38
D. V. Martynov,
12
J. N. Marx,
1
K. Mason,
12
A. Masserot,
8
T. J. Massinger,
37
M. Masso-Reid,
38
S. Mastrogiovanni,
79
,
30
F. Matichard,
12
L. Matone,
41
N. Mavalvala,
12
N. Mazumder,
56
R. McCarthy,
39
D. E. McClelland,
22
S. McCormick,
7
S. C. McGuire,
122
G. McIntyre,
1
J. McIver,
1
D. J. McManus,
22
T. McRae,
22
S. T. McWilliams,
75
D. Meacher,
90
G. D. Meadors,
31
,
10
J. Meidam,
11
A. Melatos,
84
G. Mendell,
39
R. A. Mercer,
18
E. L. Merilh,
39
M. Merzougui,
54
S. Meshkov,
1
C. Messenger,
38
C. Messick,
90
R. Metzdorff,
60
P. M. Meyers,
83
F. Mezzani,
30
,
79
H. Miao,
46
C. Michel,
66
H. Middleton,
46
E. E. Mikhailov,
123
L. Milano,
68
,
5
A. L. Miller,
6
,
79
,
30
A. Miller,
82
B. B. Miller,
82
J. Miller,
12
M. Millhouse,
33
Y. Minenkov,
15
J. Ming,
31
S. Mirshekari,
124
C. Mishra,
17
S. Mitra,
16
V. P. Mitrofanov,
50
G. Mitselmakher,
6
R. Mittleman,
12
A. Moggi,
21
M. Mohan,
36
S. R. P. Mohapatra,
12
M. Montani,
57
,
58
B. C. Moore,
92
C. J. Moore,
125
D. Moraru,
39
G. Moreno,
39
S. R. Morriss,
87
K. Mossavi,
10
B. Mours,
8
C. M. Mow-Lowry,
46
G. Mueller,
6
A. W. Muir,
91
Arunava Mukherjee,
17
D. Mukherjee,
18
S. Mukherjee,
87
N. Mukund,
16
A. Mullavey,
7
J. Munch,
112
D. J. Murphy,
41
P. G. Murray,
38
A. Mytidis,
6
I. Nardecchia,
27
,
15
L. Naticchioni,
79
,
30
R. K. Nayak,
126
K. Nedkova,
119
G. Nelemans,
53
,
11
T. J. N. Nelson,
7
M. Neri,
47
,
48
A. Neunzert,
101
G. Newton,
38
T. T. Nguyen,
22
A. B. Nielsen,
10
S. Nissanke,
53
,
11
A. Nitz,
10
F. Nocera,
36
D. Nolting,
7
M. E. N. Normandin,
87
L. K. Nuttall,
37
J. Oberling,
39
E. Ochsner,
18
J. O’Dell,
127
E. Oelker,
12
G. H. Ogin,
128
J. J. Oh,
129
S. H. Oh,
129
F. Ohme,
91
M. Oliver,
104
P. Oppermann,
10
Richard J. Oram,
7
B. O’Reilly,
7
R. O’Shaughnessy,
102
D. J. Ottaway,
112
H. Overmier,
7
B. J. Owen,
72
A. Pai,
107
S. A. Pai,
49
J. R. Palamos,
59
O. Palashov,
109
C. Palomba,
30
A. Pal-Singh,
29
H. Pan,
73
C. Pankow,
82
F. Pannarale,
91
B. C. Pant,
49
F. Paoletti,
36
,
21
A. Paoli,
36
M. A. Papa,
31
,
18
,
10
H. R. Paris,
42
W. Parker,
7
D. Pascucci,
38
A. Pasqualetti,
36
R. Passaquieti,
20
,
21
D. Passuello,
21
B. Patricelli,
20
,
21
Z. Patrick,
42
B. L. Pearlstone,
38
M. Pedraza,
1
R. Pedurand,
66
,
130
L. Pekowsky,
37
A. Pele,
7
S. Penn,
131
A. Perreca,
1
L. M. Perri,
82
M. Phelps,
38
O. J. Piccinni,
79
,
30
M. Pichot,
54
F. Piergiovanni,
57
,
58
V. Pierro,
9
G. Pillant,
36
L. Pinard,
66
I. M. Pinto,
9
M. Pitkin,
38
M. Poe,
18
R. Poggiani,
20
,
21
P. Popolizio,
36
A. Post,
10
J. Powell,
38
J. Prasad,
16
V. Predoi,
91
T. Prestegard,
83
L. R. Price,
1
M. Prijatelj,
10
,
36
M. Principe,
9
S. Privitera,
31
R. Prix,
10
G. A. Prodi,
88
,
89
L. Prokhorov,
50
O. Puncken,
10
M. Punturo,
35
P. Puppo,
30
M. P ̈urrer,
31
H. Qi,
18
J. Qin,
52
S. Qiu,
115
V. Quetschke,
87
E. A. Quintero,
1
R. Quitzow-James,
59
F. J. Raab,
39
D. S. Rabeling,
22
H. Radkins,
39
P. Raffai,
93
S. Raja,
49
C. Rajan,
49
M. Rakhmanov,
87
P. Rapagnani,
79
,
30
V. Raymond,
31
M. Razzano,
20
,
21
V. Re,
27
J. Read,
24
C. M. Reed,
39
T. Regimbau,
54
L. Rei,
48
S. Reid,
51
D. H. Reitze,
1
,
6
H. Rew,
123
S. D. Reyes,
37
F. Ricci,
79
,
30
K. Riles,
101
M. Rizzo,
102
N. A. Robertson,
1
,
38
R. Robie,
38
F. Robinet,
25
A. Rocchi,
15
L. Rolland,
8
J. G. Rollins,
1
V. J. Roma,
59
J. D. Romano,
87
R. Romano,
4
,
5
G. Romanov,
123
J. H. Romie,
7
D. Rosi ́nska,
132
,
45
S. Rowan,
38
A. R ̈udiger,
10
P. Ruggi,
36
K. Ryan,
39
S. Sachdev,
1
T. Sadecki,
39
L. Sadeghian,
18
M. Sakellariadou,
133
L. Salconi,
36
M. Saleem,
107
F. Salemi,
10
A. Samajdar,
126
L. Sammut,
115
E. J. Sanchez,
1
V. Sandberg,
39
B. Sandeen,
82
J. R. Sanders,
37
B. Sassolas,
66
B. S. Sathyaprakash,
91
P. R. Saulson,
37
O. E. S. Sauter,
101
3
R. L. Savage,
39
A. Sawadsky,
19
P. Schale,
59
R. Schilling
†
,
10
J. Schmidt,
10
P. Schmidt,
1
,
77
R. Schnabel,
29
R. M. S. Schofield,
59
A. Sch ̈onbeck,
29
E. Schreiber,
10
D. Schuette,
10
,
19
B. F. Schutz,
91
,
31
J. Scott,
38
S. M. Scott,
22
D. Sellers,
7
A. S. Sengupta,
96
D. Sentenac,
36
V. Sequino,
27
,
15
A. Sergeev,
109
Y. Setyawati,
53
,
11
D. A. Shaddock,
22
T. Shaffer,
39
M. S. Shahriar,
82
M. Shaltev,
10
B. Shapiro,
42
P. Shawhan,
64
A. Sheperd,
18
D. H. Shoemaker,
12
D. M. Shoemaker,
65
K. Siellez,
65
X. Siemens,
18
M. Sieniawska,
45
D. Sigg,
39
A. D. Silva,
13
A. Singer,
1
L. P. Singer,
69
A. Singh,
31
,
10
,
19
R. Singh,
2
A. Singhal,
14
A. M. Sintes,
104
B. J. J. Slagmolen,
22
J. R. Smith,
24
N. D. Smith,
1
R. J. E. Smith,
1
E. J. Son,
129
B. Sorazu,
38
F. Sorrentino,
48
T. Souradeep,
16
A. K. Srivastava,
85
A. Staley,
41
M. Steinke,
10
J. Steinlechner,
38
S. Steinlechner,
38
D. Steinmeyer,
10
,
19
B. C. Stephens,
18
R. Stone,
87
K. A. Strain,
38
N. Straniero,
66
G. Stratta,
57
,
58
N. A. Strauss,
61
S. Strigin,
50
R. Sturani,
124
A. L. Stuver,
7
T. Z. Summerscales,
134
L. Sun,
84
S. Sunil,
85
P. J. Sutton,
91
B. L. Swinkels,
36
M. J. Szczepa ́nczyk,
98
M. Tacca,
32
D. Talukder,
59
D. B. Tanner,
6
M. T ́apai,
97
S. P. Tarabrin,
10
A. Taracchini,
31
R. Taylor,
1
T. Theeg,
10
M. P. Thirugnanasambandam,
1
E. G. Thomas,
46
M. Thomas,
7
P. Thomas,
39
K. A. Thorne,
7
E. Thrane,
115
S. Tiwari,
14
,
89
V. Tiwari,
91
K. V. Tokmakov,
106
K. Toland,
38
C. Tomlinson,
86
M. Tonelli,
20
,
21
Z. Tornasi,
38
C. V. Torres
‡
,
87
C. I. Torrie,
1
D. T ̈oyr ̈a,
46
F. Travasso,
34
,
35
G. Traylor,
7
D. Trifir`o,
23
M. C. Tringali,
88
,
89
L. Trozzo,
135
,
21
M. Tse,
12
M. Turconi,
54
D. Tuyenbayev,
87
D. Ugolini,
136
C. S. Unnikrishnan,
99
A. L. Urban,
18
S. A. Usman,
37
H. Vahlbruch,
19
G. Vajente,
1
G. Valdes,
87
N. van Bakel,
11
M. van Beuzekom,
11
J. F. J. van den Brand,
63
,
11
C. Van Den Broeck,
11
D. C. Vander-Hyde,
37
L. van der Schaaf,
11
J. V. van Heijningen,
11
A. A. van Veggel,
38
M. Vardaro,
43
,
44
S. Vass,
1
M. Vas ́uth,
40
R. Vaulin,
12
A. Vecchio,
46
G. Vedovato,
44
J. Veitch,
46
P. J. Veitch,
112
K. Venkateswara,
137
D. Verkindt,
8
F. Vetrano,
57
,
58
A. Vicer ́e,
57
,
58
S. Vinciguerra,
46
D. J. Vine,
51
J.-Y. Vinet,
54
S. Vitale,
12
T. Vo,
37
H. Vocca,
34
,
35
C. Vorvick,
39
D. V. Voss,
6
W. D. Vousden,
46
S. P. Vyatchanin,
50
A. R. Wade,
22
L. E. Wade,
138
M. Wade,
138
M. Walker,
2
L. Wallace,
1
S. Walsh,
31
,
10
G. Wang,
14
,
58
H. Wang,
46
M. Wang,
46
X. Wang,
71
Y. Wang,
52
R. L. Ward,
22
J. Warner,
39
M. Was,
8
B. Weaver,
39
L.-W. Wei,
54
M. Weinert,
10
A. J. Weinstein,
1
R. Weiss,
12
L. Wen,
52
P. Weßels,
10
T. Westphal,
10
K. Wette,
10
J. T. Whelan,
102
B. F. Whiting,
6
R. D. Williams,
1
A. R. Williamson,
91
J. L. Willis,
139
B. Willke,
19
,
10
M. H. Wimmer,
10
,
19
W. Winkler,
10
C. C. Wipf,
1
H. Wittel,
10
,
19
G. Woan,
38
J. Woehler,
10
J. Worden,
39
J. L. Wright,
38
D. S. Wu,
10
G. Wu,
7
J. Yablon,
82
W. Yam,
12
H. Yamamoto,
1
C. C. Yancey,
64
H. Yu,
12
M. Yvert,
8
A. Zadro ̇zny,
113
L. Zangrando,
44
M. Zanolin,
98
J.-P. Zendri,
44
M. Zevin,
82
L. Zhang,
1
M. Zhang,
123
Y. Zhang,
102
C. Zhao,
52
M. Zhou,
82
Z. Zhou,
82
X. J. Zhu,
52
M. E. Zucker,
1
,
12
S. E. Zuraw,
119
and J. Zweizig
1
(LIGO Scientific Collaboration and Virgo Collaboration)
†
Deceased, May 2015.
‡
Deceased, March 2015.
1
LIGO, California Institute of Technology, Pasadena, CA 91125, USA
2
Louisiana State University, Baton Rouge, LA 70803, USA
3
American University, Washington, D.C. 20016, USA
4
Universit`a di Salerno, Fisciano, I-84084 Salerno, Italy
5
INFN, Sezione di Napoli, Complesso Universitario di Monte S.Angelo, I-80126 Napoli, Italy
6
University of Florida, Gainesville, FL 32611, USA
7
LIGO Livingston Observatory, Livingston, LA 70754, USA
8
Laboratoire d’Annecy-le-Vieux de Physique des Particules (LAPP),
Universit ́e Savoie Mont Blanc, CNRS/IN2P3, F-74941 Annecy-le-Vieux, France
9
University of Sannio at Benevento, I-82100 Benevento,
Italy and INFN, Sezione di Napoli, I-80100 Napoli, Italy
10
Albert-Einstein-Institut, Max-Planck-Institut f ̈ur Gravitationsphysik, D-30167 Hannover, Germany
11
Nikhef, Science Park, 1098 XG Amsterdam, The Netherlands
12
LIGO, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
13
Instituto Nacional de Pesquisas Espaciais, 12227-010 S ̃ao Jos ́e dos Campos, S ̃ao Paulo, Brazil
14
INFN, Gran Sasso Science Institute, I-67100 L’Aquila, Italy
15
INFN, Sezione di Roma Tor Vergata, I-00133 Roma, Italy
16
Inter-University Centre for Astronomy and Astrophysics, Pune 411007, India
17
International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bangalore 560012, India
18
University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
19
Leibniz Universit ̈at Hannover, D-30167 Hannover, Germany
20
Universit`a di Pisa, I-56127 Pisa, Italy
21
INFN, Sezione di Pisa, I-56127 Pisa, Italy
22
Australian National University, Canberra, Australian Capital Territory 0200, Australia
23
The University of Mississippi, University, MS 38677, USA
24
California State University Fullerton, Fullerton, CA 92831, USA
25
LAL, Univ. Paris-Sud, CNRS/IN2P3, Universit ́e Paris-Saclay, Orsay, France
4
26
Chennai Mathematical Institute, Chennai 603103, India
27
Universit`a di Roma Tor Vergata, I-00133 Roma, Italy
28
University of Southampton, Southampton SO17 1BJ, United Kingdom
29
Universit ̈at Hamburg, D-22761 Hamburg, Germany
30
INFN, Sezione di Roma, I-00185 Roma, Italy
31
Albert-Einstein-Institut, Max-Planck-Institut f ̈ur Gravitationsphysik, D-14476 Potsdam-Golm, Germany
32
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
33
Montana State University, Bozeman, MT 59717, USA
34
Universit`a di Perugia, I-06123 Perugia, Italy
35
INFN, Sezione di Perugia, I-06123 Perugia, Italy
36
European Gravitational Observatory (EGO), I-56021 Cascina, Pisa, Italy
37
Syracuse University, Syracuse, NY 13244, USA
38
SUPA, University of Glasgow, Glasgow G12 8QQ, United Kingdom
39
LIGO Hanford Observatory, Richland, WA 99352, USA
40
Wigner RCP, RMKI, H-1121 Budapest, Konkoly Thege Mikl ́os ́ut 29-33, Hungary
41
Columbia University, New York, NY 10027, USA
42
Stanford University, Stanford, CA 94305, USA
43
Universit`a di Padova, Dipartimento di Fisica e Astronomia, I-35131 Padova, Italy
44
INFN, Sezione di Padova, I-35131 Padova, Italy
45
CAMK-PAN, 00-716 Warsaw, Poland
46
University of Birmingham, Birmingham B15 2TT, United Kingdom
47
Universit`a degli Studi di Genova, I-16146 Genova, Italy
48
INFN, Sezione di Genova, I-16146 Genova, Italy
49
RRCAT, Indore MP 452013, India
50
Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia
51
SUPA, University of the West of Scotland, Paisley PA1 2BE, United Kingdom
52
University of Western Australia, Crawley, Western Australia 6009, Australia
53
Department of Astrophysics/IMAPP, Radboud University Nijmegen,
P.O. Box 9010, 6500 GL Nijmegen, The Netherlands
54
Artemis, Universit ́e Cˆote d’Azur, CNRS, Observatoire Cˆote d’Azur, CS 34229, Nice cedex 4, France
55
Institut de Physique de Rennes, CNRS, Universit ́e de Rennes 1, F-35042 Rennes, France
56
Washington State University, Pullman, WA 99164, USA
57
Universit`a degli Studi di Urbino “Carlo Bo,” I-61029 Urbino, Italy
58
INFN, Sezione di Firenze, I-50019 Sesto Fiorentino, Firenze, Italy
59
University of Oregon, Eugene, OR 97403, USA
60
Laboratoire Kastler Brossel, UPMC-Sorbonne Universit ́es, CNRS,
ENS-PSL Research University, Coll`ege de France, F-75005 Paris, France
61
Carleton College, Northfield, MN 55057, USA
62
Astronomical Observatory Warsaw University, 00-478 Warsaw, Poland
63
VU University Amsterdam, 1081 HV Amsterdam, The Netherlands
64
University of Maryland, College Park, MD 20742, USA
65
Center for Relativistic Astrophysics and School of Physics,
Georgia Institute of Technology, Atlanta, GA 30332, USA
66
Laboratoire des Mat ́eriaux Avanc ́es (LMA), CNRS/IN2P3, F-69622 Villeurbanne, France
67
Universit ́e Claude Bernard Lyon 1, F-69622 Villeurbanne, France
68
Universit`a di Napoli “Federico II,” Complesso Universitario di Monte S.Angelo, I-80126 Napoli, Italy
69
NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA
70
RESCEU, University of Tokyo, Tokyo, 113-0033, Japan.
71
Tsinghua University, Beijing 100084, China
72
Texas Tech University, Lubbock, TX 79409, USA
73
National Tsing Hua University, Hsinchu City, 30013 Taiwan, Republic of China
74
Charles Sturt University, Wagga Wagga, New South Wales 2678, Australia
75
West Virginia University, Morgantown, WV 26506, USA
76
University of Chicago, Chicago, IL 60637, USA
77
Caltech CaRT, Pasadena, CA 91125, USA
78
Korea Institute of Science and Technology Information, Daejeon 305-806, Korea
79
Universit`a di Roma “La Sapienza,” I-00185 Roma, Italy
80
University of Brussels, Brussels 1050, Belgium
81
Sonoma State University, Rohnert Park, CA 94928, USA
82
Center for Interdisciplinary Exploration & Research in Astrophysics (CIERA),
Northwestern University, Evanston, IL 60208, USA
83
University of Minnesota, Minneapolis, MN 55455, USA
5
84
The University of Melbourne, Parkville, Victoria 3010, Australia
85
Institute for Plasma Research, Bhat, Gandhinagar 382428, India
86
The University of Sheffield, Sheffield S10 2TN, United Kingdom
87
The University of Texas Rio Grande Valley, Brownsville, TX 78520, USA
88
Universit`a di Trento, Dipartimento di Fisica, I-38123 Povo, Trento, Italy
89
INFN, Trento Institute for Fundamental Physics and Applications, I-38123 Povo, Trento, Italy
90
The Pennsylvania State University, University Park, PA 16802, USA
91
Cardiff University, Cardiff CF24 3AA, United Kingdom
92
Montclair State University, Montclair, NJ 07043, USA
93
MTA E ̈otv ̈os University, “Lendulet” Astrophysics Research Group, Budapest 1117, Hungary
94
National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
95
School of Mathematics, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
96
Indian Institute of Technology, Gandhinagar Ahmedabad Gujarat 382424, India
97
University of Szeged, D ́om t ́er 9, Szeged 6720, Hungary
98
Embry-Riddle Aeronautical University, Prescott, AZ 86301, USA
99
Tata Institute of Fundamental Research, Mumbai 400005, India
100
INAF, Osservatorio Astronomico di Capodimonte, I-80131, Napoli, Italy
101
University of Michigan, Ann Arbor, MI 48109, USA
102
Rochester Institute of Technology, Rochester, NY 14623, USA
103
NCSA, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
104
Universitat de les Illes Balears, IAC3—IEEC, E-07122 Palma de Mallorca, Spain
105
University of Bia lystok, 15-424 Bia lystok, Poland
106
SUPA, University of Strathclyde, Glasgow G1 1XQ, United Kingdom
107
IISER-TVM, CET Campus, Trivandrum Kerala 695016, India
108
Canadian Institute for Theoretical Astrophysics,
University of Toronto, Toronto, Ontario M5S 3H8, Canada
109
Institute of Applied Physics, Nizhny Novgorod, 603950, Russia
110
Pusan National University, Busan 609-735, Korea
111
Hanyang University, Seoul 133-791, Korea
112
University of Adelaide, Adelaide, South Australia 5005, Australia
113
NCBJ, 05-400
́
Swierk-Otwock, Poland
114
IM-PAN, 00-956 Warsaw, Poland
115
Monash University, Victoria 3800, Australia
116
Seoul National University, Seoul 151-742, Korea
117
The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
118
University of Alabama in Huntsville, Huntsville, AL 35899, USA
119
University of Massachusetts-Amherst, Amherst, MA 01003, USA
120
ESPCI, CNRS, F-75005 Paris, France
121
Universit`a di Camerino, Dipartimento di Fisica, I-62032 Camerino, Italy
122
Southern University and A&M College, Baton Rouge, LA 70813, USA
123
College of William and Mary, Williamsburg, VA 23187, USA
124
Instituto de F ́ısica Te ́orica, University Estadual Paulista/ICTP South
American Institute for Fundamental Research, S ̃ao Paulo SP 01140-070, Brazil
125
University of Cambridge, Cambridge CB2 1TN, United Kingdom
126
IISER-Kolkata, Mohanpur, West Bengal 741252, India
127
Rutherford Appleton Laboratory, HSIC, Chilton, Didcot, Oxon OX11 0QX, United Kingdom
128
Whitman College, 345 Boyer Avenue, Walla Walla, WA 99362 USA
129
National Institute for Mathematical Sciences, Daejeon 305-390, Korea
130
Universit ́e de Lyon, F-69361 Lyon, France
131
Hobart and William Smith Colleges, Geneva, NY 14456, USA
132
Janusz Gil Institute of Astronomy, University of Zielona G ́ora, 65-265 Zielona G ́ora, Poland
133
King’s College London, University of London, London WC2R 2LS, United Kingdom
134
Andrews University, Berrien Springs, MI 49104, USA
135
Universit`a di Siena, I-53100 Siena, Italy
136
Trinity University, San Antonio, TX 78212, USA
137
University of Washington, Seattle, WA 98195, USA
138
Kenyon College, Gambier, OH 43022, USA
139
Abilene Christian University, Abilene, TX 79699, USA
We report on a comprehensive all-sky search for periodic gravitational waves in the frequency band
100-1500 Hz and with a frequency time derivative in the range of [
−
1
.
18
,
+1
.
00]
×
10
−
8
Hz/s. Such
a signal could be produced by a nearby spinning and slightly non-axisymmetric isolated neutron
star in our galaxy. This search uses the data from the Initial LIGO sixth science run and covers a
larger parameter space with respect to any past search. A
Loosely Coherent
detection pipeline was
6
applied to follow up weak outliers in both Gaussian (95% recovery rate) and non-Gaussian (75%
recovery rate) bands. No gravitational wave signals were observed, and upper limits were placed on
their strength. Our smallest upper limit on worst-case (linearly polarized) strain amplitude
h
0
is
9
.
7
×
10
−
25
near 169 Hz, while at the high end of our frequency range we achieve a worst-case upper
limit of 5
.
5
×
10
−
24
. Both cases refer to all sky locations and entire range of frequency derivative
values.
I. INTRODUCTION
In this paper we report the results of a compre-
hensive all-sky search for continuous, nearly monochro-
matic gravitational waves in data from LIGO’s sixth
science (S6) run. The search covered frequencies from
100 Hz through 1500 Hz and frequency derivatives from
−
1
.
18
×
10
−
8
Hz/s through 1
.
00
×
10
−
8
Hz/s.
A number of searches for periodic gravitational waves
have been carried out previously in LIGO data [1–10],
including coherent searches for gravitational radiation
from known radio and X-ray pulsars. An Einstein@Home
search running on the BOINC infrastructure [11] has per-
formed blind all-sky searches on S4 and S5 data [12–14].
The results in this paper were produced with the Pow-
erFlux search program.
It was first described in [1]
together with two other semi-coherent search pipelines
(Hough, Stackslide). The sensitivities of all three meth-
ods were compared, with PowerFlux showing better re-
sults in frequency bands lacking severe spectral artifacts.
A subsequent article [3] based on the data from the S5
run featured improved upper limits and a systematic out-
lier follow-up search based on the
Loosely Coherent
algo-
rithm [15].
The analysis of the data set from the sixth science run
described in this paper has several distinguishing features
from previously published results:
•
A number of upgrades to the detector were made
in order to field-test the technology for Advanced
LIGO interferometers. This resulted in a factor of
about two improvement in intrinsic noise level at
high frequencies compared to previously published
results [3].
•
The higher sensitivity allowed us to use less data
while still improving upper limits in high frequency
bands by 25% over previously published results.
This smaller dataset allowed covering larger param-
eter space, and comprehensive exploration of high
frequency data.
•
This search improved on previous analyses by par-
titioning the data in
≈
1 month chunks and look-
ing for signals in any contiguous sequence of these
chunks. This enables detections of signals that con-
form to ideal signal model over only part of the
data. Such signals could arise because of a glitch,
or because of influence of a long-period companion
object.
•
The upgrades to the detector, while improving sen-
sitivity on average, introduced a large number of
detector artifacts, with 20% of frequency range con-
taminated by non-Gaussian noise. We addressed
this issue by developing a new
Universal statistic
[16] that provides correct upper limits regardless of
the noise distribution of the underlying data, while
still showing close to optimal performance for Gaus-
sian data.
We have observed no evidence of gravitational radia-
tion and have established the most sensitive upper limits
to date in the frequency band 100-1500 Hz. Our smallest
95% confidence level upper limit on worst-case (linearly
polarized) strain amplitude
h
0
is 9
.
7
×
10
−
25
near 169 Hz,
while at the high end of our frequency range we achieve a
worst-case upper limit of 5
.
5
×
10
−
24
. Both cases refer to
all sky locations and entire range of frequency derivative
values.
II. LIGO INTERFEROMETERS AND S6
SCIENCE RUN
The LIGO gravitational wave network consists of two
observatories, one in Hanford, Washington and the other
in Livingston, Louisiana, separated by a 3000 km base-
line. During the S6 run each site housed one suspended
interferometer with 4 km long arms.
While the sixth science run spanned a
≈
15 months pe-
riod of data acquisition, this analysis used only data from
GPS 951534120 (2010 Mar 02 03:01:45 UTC) through
GPS 971619922 (2010 Oct 20 14:25:07 UTC), for which
strain sensitivity was best. Since interferometers spo-
radically fall out of operation (“lose lock”) due to en-
vironmental or instrumental disturbances or for sched-
uled maintenance periods, the dataset was not contigu-
ous. The Hanford interferometer H1 had a duty factor of
53%, while the Livingston interferometer L1 had a duty
factor of 51%. The strain sensitivity was not uniform,
exhibiting a
∼
50% daily variation from anthropogenic
activity as well as gradual improvement toward the end
of the run [17, 18].
Non-stationarity of noise was especially severe at fre-
quencies below 100 Hz, and since the average detector
sensitivity for such frequencies was not significantly bet-
ter than that observed in the longer S5 run [3], this search
was restricted to frequencies above 100 Hz.
A detailed description of the instruments and data can
be found in [19].
7
Frequency (Hz)
h0
50
300
500
700
900
1100
1300
1500
1e−25
1e−24
1e−23
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worst case (linear)
best case (circular)
60 Hz harmonics
FIG. 1. S6 upper limits. The upper (yellow) curve shows worst-case (linearly polarized) 95% CL upper limits in analyzed 0.25 Hz
bands (see Table I for list of excluded bands). The lower (grey) curve shows upper limits assuming a circularly polarized source.
The values of solid points and circles mark frequencies within 1
.
25 Hz of 60 Hz power line harmonics for circularly (solid points)
and linearly (open circles) polarized sources. The data for this plot can be found in [20]. (color online)
III. THE SEARCH FOR CONTINUOUS
GRAVITATIONAL RADIATION
A. Overview
In this paper we assume a classical model of a spin-
ning neutron star with a rotating quadrupole moment
that produces circularly polarized gravitational radiation
along the rotation axis and linearly polarized radiation
in the directions perpendicular to the rotation axis. The
linear polarization is the worst case as such signals con-
tribute the smallest amount of power to the detector.
The strain signal template is assumed to be
h
(
t
) =
h
0
(
F
+
(
t,α
0
,δ
0
,ψ
)
1+cos
2
(
ι
)
2
cos(Φ(
t
))+
+
F
×
(
t,α
0
,δ
0
,ψ
) cos(
ι
) sin(Φ(
t
))
)
,
(1)
where
F
+
and
F
×
characterize the detector responses to
signals with “+” and “
×
” quadrupolar polarizations [1–
3], the sky location is described by right ascension
α
0
and
declination
δ
0
, the inclination of the source rotation axis
to the line of sight is denoted
ι
, and the phase evolution
of the signal is given by the formula
Φ(
t
) = 2
π
(
f
source
·
(
t
−
t
0
) +
f
(1)
·
(
t
−
t
0
)
2
/
2
)
+
φ
,
(2)
with
f
source
being the source frequency and
f
(1)
denoting
the first frequency derivative (which, when negative, is
termed the
spindown
). We use
t
to denote the time in
the Solar System barycenter frame. The initial phase
φ
is
computed relative to reference time
t
0
. When expressed
as a function of local time of ground-based detectors the
equation 2 acquires sky-position-dependent Doppler shift
terms. We use
ψ
to denote the polarization angle of the