of 16
SEARCHES FOR CONTINUOUS GRAVITATIONAL WAVES FROM NINE YOUNG SUPERNOVA REMNANTS
J. Aasi
1
, B. P. Abbott
1
, R. Abbott
1
, T. Abbott
2
, M. R. Abernathy
1
, F. Acernese
3
,
4
, K. Ackley
5
, C. Adams
6
, T. Adams
7
,
8
,
P. Addesso
9
, R. X. Adhikari
1
, V. Adya
10
, C. Affeldt
10
, M. Agathos
11
, K. Agatsuma
11
, N. Aggarwal
12
, O. D. Aguiar
13
,
A. Ain
14
, P. Ajith
15
, A. Alemic
16
, B. Allen
17
,
18
, A. Allocca
19
,
20
, D. Amariutei
5
, S. B. Anderson
1
, W. G. Anderson
18
,
K. Arai
1
, M. C. Araya
1
, C. Arceneaux
21
, J. S. Areeda
22
,S.Ast
23
, S. M. Aston
6
, P. Astone
24
, P. Aufmuth
23
, C. Aulbert
17
,
B. E. Aylott
25
, S. Babak
26
, P. T. Baker
27
, F. Baldaccini
28
,
29
, G. Ballardin
30
, S. W. Ballmer
16
, J. C. Barayoga
1
,
M. Barbet
5
, S. Barclay
31
, B. C. Barish
1
, D. Barker
32
, F. Barone
3
,
4
, B. Barr
31
, L. Barsotti
12
, M. Barsuglia
33
,
J. Bartlett
32
, M. A. Barton
32
, I. Bartos
34
, R. Bassiri
35
, A. Basti
20
,
36
, J. C. Batch
32
, Th. S. Bauer
11
, C. Baune
10
,
V. Bavigadda
30
, B. Behnke
26
, M. Bejger
37
, C. Belczynski
38
, A. S. Bell
31
, C. Bell
31
, M. Benacquista
39
, J. Bergman
32
,
G. Bergmann
10
, C. P. L. Berry
25
, D. Bersanetti
40
,
41
, A. Bertolini
11
, J. Betzwieser
6
, S. Bhagwat
16
, R. Bhandare
42
,
I. A. Bilenko
43
, G. Billingsley
1
, J. Birch
6
, S. Biscans
12
, M. Bitossi
20
,
30
, C. Biwer
16
, M. A. Bizouard
44
, J. K. Blackburn
1
,
L. Blackburn
45
, C. D. Blair
46
, D. Blair
46
, S. Bloemen
11
,
47
, O. Bock
17
, T. P. Bodiya
12
, M. Boer
48
, G. Bogaert
48
,
P. Bojtos
49
, C. Bond
25
, F. Bondu
50
, L. Bonelli
20
,
36
, R. Bonnand
8
, R. Bork
1
, M. Born
10
, V. Boschi
20
, Sukanta Bose
14
,
51
,
C. Bradaschia
20
, P. R. Brady
18
, V. B. Braginsky
43
, M. Branchesi
52
,
53
, J. E. Brau
54
, T. Briant
55
, D. O. Bridges
6
,
A. Brillet
48
, M. Brinkmann
10
, V. Brisson
44
, A. F. Brooks
1
, D. A. Brown
16
, D. D. Brown
25
, N. M. Brown
12
, S. Buchman
35
,
A. Buikema
12
, T. Bulik
38
, H. J. Bulten
11
,
56
, A. Buonanno
57
, D. Buskulic
8
,C.Buy
33
, L. Cadonati
58
, G. Cagnoli
59
,
J. Calderón Bustillo
60
, E. Calloni
4
,
61
, J. B. Camp
45
, K. C. Cannon
62
,J.Cao
63
, C. D. Capano
57
, F. Carbognani
30
,
S. Caride
64
, S. Caudill
18
, M. Cavaglià
21
, F. Cavalier
44
, R. Cavalieri
30
, G. Cella
20
, C. Cepeda
1
, E. Cesarini
65
,
R. Chakraborty
1
, T. Chalermsongsak
1
, S. J. Chamberlin
18
, S. Chao
66
, P. Charlton
67
, E. Chassande-Mottin
33
, Y. Chen
68
,
A. Chincarini
41
, A. Chiummo
30
, H. S. Cho
69
, M. Cho
57
, J. H. Chow
70
, N. Christensen
71
, Q. Chu
46
, S. Chua
55
, S. Chung
46
,
G. Ciani
5
, F. Clara
32
, J. A. Clark
58
, F. Cleva
48
, E. Coccia
72
,
73
, P.-F. Cohadon
55
, A. Colla
24
,
74
, C. Collette
75
,
M. Colombini
29
, L. Cominsky
76
, M. Constancio Jr
13
, A. Conte
24
,
74
, D. Cook
32
, T. R. Corbitt
2
, N. Cornish
27
, A. Corsi
77
,
C. A. Costa
13
, M. W. Coughlin
71
, J.-P. Coulon
48
, S. Countryman
34
, P. Couvares
16
, D. M. Coward
46
, M. J. Cowart
6
,
D. C. Coyne
1
, R. Coyne
77
, K. Craig
31
, J. D. E. Creighton
18
, T. D. Creighton
39
, J. Cripe
2
, S. G. Crowder
78
, A. Cumming
31
,
L. Cunningham
31
, E. Cuoco
30
, C. Cutler
68
, K. Dahl
10
, T. Dal Canton
17
, M. Damjanic
10
, S. L. Danilishin
46
,
S. D
Antonio
65
, K. Danzmann
10
,
23
, L. Dartez
39
, V. Dattilo
30
,I.Dave
42
, H. Daveloza
39
, M. Davier
44
, G. S. Davies
31
,
E. J. Daw
79
,R.Day
30
, D. DeBra
35
, G. Debreczeni
80
, J. Degallaix
59
, M. De Laurentis
4
,
61
, S. Deléglise
55
, W. Del Pozzo
25
,
T. Denker
10
, T. Dent
17
, H. Dereli
48
, V. Dergachev
1
, R. De Rosa
4
,
61
, R. T. DeRosa
2
, R. DeSalvo
9
, S. Dhurandhar
14
,
M. Díaz
39
, L. Di Fiore
4
, A. Di Lieto
20
,
36
, I. Di Palma
26
, A. Di Virgilio
20
, G. Dojcinoski
81
, V. Dolique
59
, E. Dominguez
82
,
F. Donovan
12
, K. L. Dooley
10
, S. Doravari
6
, R. Douglas
31
, T. P. Downes
18
, M. Drago
83
,
84
, J. C. Driggers
1
,Z.Du
63
,
M. Ducrot
8
, S. Dwyer
32
, T. Eberle
10
,T.Edo
79
, M. Edwards
7
, M. Edwards
71
,A.Ef
fl
er
2
, H.-B. Eggenstein
17
, P. Ehrens
1
,
J. Eichholz
5
, S. S. Eikenberry
5
, R. Essick
12
, T. Etzel
1
, M. Evans
12
,T.Evans
6
, M. Factourovich
34
, V. Fafone
65
,
72
,
S. Fairhurst
7
,X.Fan
31
, Q. Fang
46
, S. Farinon
41
, B. Farr
85
,W.M.Farr
25
, M. Favata
81
,M.Fays
7
, H. Fehrmann
17
,
M. M. Fejer
35
, D. Feldbaum
5
,
6
, I. Ferrante
20
,
36
, E. C. Ferreira
13
, F. Ferrini
30
, F. Fidecaro
20
,
36
, I. Fiori
30
, R. P. Fisher
16
,
R. Flaminio
59
, J.-D. Fournier
48
, S. Franco
44
, S. Frasca
24
,
74
, F. Frasconi
20
, Z. Frei
49
, A. Freise
25
, R. Frey
54
, T. T. Fricke
10
,
P. Fritschel
12
, V. V. Frolov
6
, S. Fuentes-Tapia
39
, P. Fulda
5
, M. Fyffe
6
, J. R. Gair
86
, L. Gammaitoni
28
,
29
, S. Gaonkar
14
,
F. Garu
fi
61
,
4
, A. Gatto
33
, N. Gehrels
45
, G. Gemme
41
, B. Gendre
48
, E. Genin
30
, A. Gennai
20
, L. Á. Gergely
87
, S. Ghosh
11
,
47
,
J. A. Giaime
6
,
2
, K. D. Giardina
6
, A. Giazotto
20
, J. Gleason
5
, E. Goetz
17
, R. Goetz
5
, L. Gondan
49
, G. González
2
,
N. Gordon
31
, M. L. Gorodetsky
43
, S. Gossan
68
, S. Gossler
10
, R. Gouaty
8
, C. Gräf
31
, P. B. Graff
45
, M. Granata
59
,
A. Grant
31
, S. Gras
12
, C. Gray
32
, R. J. S. Greenhalgh
88
, A. M. Gretarsson
89
, P. Groot
47
, H. Grote
10
, S. Grunewald
26
,
G. M. Guidi
52
,
53
, C. J. Guido
6
, X. Guo
63
, K. Gushwa
1
, E. K. Gustafson
1
, R. Gustafson
64
, J. Hacker
22
, E. D. Hall
1
,
G. Hammond
31
, M. Hanke
10
, J. Hanks
32
, C. Hanna
90
, M. D. Hannam
7
, J. Hanson
6
, T. Hardwick
2
,
54
, J. Harms
53
,
G. M. Harry
91
, I. W. Harry
26
, M. Hart
31
, M. T. Hartman
5
, C.-J. Haster
25
, K. Haughian
31
, A. Heidmann
55
, M. Heintze
5
,
6
,
G. Heinzel
10
, H. Heitmann
48
, P. Hello
44
, G. Hemming
30
, M. Hendry
31
, I. S. Heng
31
, A. W. Heptonstall
1
, M. Heurs
10
,
M. Hewitson
10
, S. Hild
31
, D. Hoak
58
, K. A. Hodge
1
, D. Hofman
59
, S. E. Hollitt
92
, K. Holt
6
, P. Hopkins
7
, D. J. Hosken
92
,
J. Hough
31
, E. Houston
31
, E. J. Howell
46
,Y.M.Hu
31
, E. Huerta
93
, B. Hughey
89
, S. Husa
60
, S. H. Huttner
31
, M. Huynh
18
,
T. Huynh-Dinh
6
, A. Idrisy
90
, N. Indik
17
, D. R. Ingram
32
, R. Inta
90
, G. Islas
22
, J. C. Isler
16
, T. Isogai
12
, B. R. Iyer
94
,
K. Izumi
32
, M. Jacobson
1
, H. Jang
95
, P. Jaranowski
96
, S. Jawahar
97
,Y.Ji
63
, F. Jiménez-Forteza
60
, W. W. Johnson
2
,
D. I. Jones
98
, R. Jones
31
, R. J. G. Jonker
11
,L.Ju
46
, Haris K
99
, V. Kalogera
85
, S. Kandhasamy
21
, G. Kang
95
, J. B. Kanner
1
,
M. Kasprzack
30
,
44
, E. Katsavounidis
12
, W. Katzman
6
, H. Kaufer
23
, S. Kaufer
23
, T. Kaur
46
, K. Kawabe
32
, F. Kawazoe
10
,
F. Kéfélian
48
, G. M. Keiser
35
, D. Keitel
17
, D. B. Kelley
16
, W. Kells
1
, D. G. Keppel
17
, J. S. Key
39
, A. Khalaidovski
10
,
F. Y. Khalili
43
, E. A. Khazanov
100
, C. Kim
95
,
101
, K. Kim
102
,N.G.Kim
95
, N. Kim
35
, Y.-M. Kim
69
, E. J. King
92
, P. J. King
32
,
D. L. Kinzel
6
, J. S. Kissel
32
, S. Klimenko
5
, J. Kline
18
, S. Koehlenbeck
10
, K. Kokeyama
2
, V. Kondrashov
1
, M. Korobko
10
,
W. Z. Korth
1
, I. Kowalska
38
, D. B. Kozak
1
, V. Kringel
10
, B. Krishnan
17
, A. Królak
103
,
104
, C. Krueger
23
, G. Kuehn
10
,
A. Kumar
105
, P. Kumar
16
,L.Kuo
66
, A. Kutynia
103
, M. Landry
32
, B. Lantz
35
, S. Larson
85
, P. D. Lasky
106
, A. Lazzarini
1
,
The Astrophysical Journal,
813:39
(
16pp
)
, 2015 November 1
doi:10.1088
/
0004-637X
/
813
/
1
/
39
© 2015. The American Astronomical Society. All rights reserved.
1
C. Lazzaro
107
, C. Lazzaro
58
,J.Le
85
, P. Leaci
26
, S. Leavey
31
, E. Lebigot
33
, E. O. Lebigot
63
, C. H. Lee
69
, H. K. Lee
102
,
H. M. Lee
101
, M. Leonardi
83
,
84
, J. R. Leong
10
, N. Leroy
44
, N. Letendre
8
, Y. Levin
108
, B. Levine
32
, J. Lewis
1
,T.G.F.Li
1
,
K. Libbrecht
1
, A. Libson
12
, A. C. Lin
35
, T. B. Littenberg
85
, N. A. Lockerbie
97
, V. Lockett
22
, J. Logue
31
, A. L. Lombardi
58
,
M. Lorenzini
73
, V. Loriette
109
, M. Lormand
6
, G. Losurdo
53
, J. Lough
17
, M. J. Lubinski
32
, H. Lück
10
,
23
, A. P. Lundgren
17
,
R. Lynch
12
,Y.Ma
46
, J. Macarthur
31
, T. MacDonald
35
, B. Machenschalk
17
, M. MacInnis
12
, D. M. Macleod
2
,
F. Magaña na-Sandoval
16
, R. Magee
51
, M. Mageswaran
1
, C. Maglione
82
, K. Mailand
1
, E. Majorana
24
, I. Maksimovic
109
,
V. Malvezzi
65
,
72
, N. Man
48
, I. Mandel
25
, V. Mandic
78
, V. Mangano
31
, V. Mangano
24
,
74
, G. L. Mansell
70
,
M. Mantovani
20
,
30
, F. Marchesoni
29
,
110
, F. Marion
8
, S. Márka
34
, Z. Márka
34
, A. Markosyan
35
, E. Maros
1
,
F. Martelli
52
,
53
, L. Martellini
48
, I. W. Martin
31
, R. M. Martin
5
, D. Martynov
1
, J. N. Marx
1
, K. Mason
12
, A. Masserot
8
,
T. J. Massinger
16
, F. Matichard
12
, L. Matone
34
, N. Mavalvala
12
, N. Mazumder
99
, G. Mazzolo
17
, R. McCarthy
32
,
D. E. McClelland
70
, S. McCormick
6
, S. C. McGuire
111
, G. McIntyre
1
, J. McIver
58
, K. McLin
76
, S. McWilliams
93
,
D. Meacher
48
, G. D. Meadors
64
, J. Meidam
11
, M. Meinders
23
, A. Melatos
106
, G. Mendell
32
, R. A. Mercer
18
, S. Meshkov
1
,
C. Messenger
31
, P. M. Meyers
78
, F. Mezzani
24
,
74
, H. Miao
25
, C. Michel
59
, H. Middleton
25
, E. E. Mikhailov
112
,
L. Milano
4
,
61
, A. Miller
113
, J. Miller
12
, M. Millhouse
27
, Y. Minenkov
65
, J. Ming
26
, S. Mirshekari
114
, C. Mishra
15
,
S. Mitra
14
, V. P. Mitrofanov
43
, G. Mitselmakher
5
, R. Mittleman
12
, B. Moe
18
, A. Moggi
20
, M. Mohan
30
, S. D. Mohanty
39
,
S. R. P. Mohapatra
12
, B. Moore
81
, D. Moraru
32
, G. Moreno
32
, S. R. Morriss
39
, K. Mossavi
10
, B. Mours
8
,
C. M. Mow-Lowry
10
, C. L. Mueller
5
, G. Mueller
5
, S. Mukherjee
39
, A. Mullavey
6
, J. Munch
92
, D. Murphy
34
,
P. G. Murray
31
, A. Mytidis
5
, M. F. Nagy
80
, I. Nardecchia
65
,
72
, T. Nash
1
, L. Naticchioni
24
,
74
,R.K.Nayak
115
, V. Necula
5
,
K. Nedkova
58
, G. Nelemans
11
,
47
, I. Neri
28
,
29
, M. Neri
40
,
41
, G. Newton
31
, T. Nguyen
70
, A. B. Nielsen
17
, S. Nissanke
68
,
A. H. Nitz
16
, F. Nocera
30
, D. Nolting
6
, M. E. N. Normandin
39
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18
, E. Ochsner
18
,J.O
Dell
88
, E. Oelker
12
,
G. H. Ogin
116
,J.J.Oh
117
,S.H.Oh
117
, F. Ohme
7
, P. Oppermann
10
, R. Oram
6
,B.O
Reilly
6
, W. Ortega
82
,
R. O
Shaughnessy
118
, C. Osthelder
1
, C. D. Ott
68
, D. J. Ottaway
92
, R. S. Ottens
5
, H. Overmier
6
, B. J. Owen
90
,
C. Padilla
22
,A.Pai
99
,S.Pai
42
, O. Palashov
100
, C. Palomba
24
, A. Pal-Singh
10
,H.Pan
66
, C. Pankow
18
, F. Pannarale
7
,
B. C. Pant
42
, F. Paoletti
20
,
30
, M. A. Papa
18
,
26
, H. Paris
35
, A. Pasqualetti
30
, R. Passaquieti
20
,
36
, D. Passuello
20
,
Z. Patrick
35
, M. Pedraza
1
, L. Pekowsky
16
, A. Pele
32
, S. Penn
119
, A. Perreca
16
, M. Phelps
1
, M. Pichot
48
,
F. Piergiovanni
52
,
53
, V. Pierro
9
, G. Pillant
30
, L. Pinard
59
, I. M. Pinto
9
, M. Pitkin
31
, J. Poeld
10
, R. Poggiani
20
,
36
, A. Post
17
,
A. Poteomkin
100
, J. Powell
31
, J. Prasad
14
, V. Predoi
7
, S. Premachandra
108
, T. Prestegard
78
, L. R. Price
1
, M. Prijatelj
30
,
M. Principe
9
, S. Privitera
1
, R. Prix
17
, G. A. Prodi
83
,
84
, L. Prokhorov
43
, O. Puncken
39
, M. Punturo
29
, P. Puppo
24
,
M. Pürrer
7
, J. Qin
46
, V. Quetschke
39
, E. Quintero
1
, G. Quiroga
82
, R. Quitzow-James
54
, F. J. Raab
32
, D. S. Rabeling
11
,
56
,
70
,
I. Rácz
80
, H. Radkins
32
, P. Raffai
49
, S. Raja
42
, G. Rajalakshmi
120
, M. Rakhmanov
39
, K. Ramirez
39
, P. Rapagnani
24
,
74
,
V. Raymond
1
, M. Razzano
20
,
36
,V.Re
65
,
72
, C. M. Reed
32
, T. Regimbau
48
, L. Rei
41
, S. Reid
121
, D. H. Reitze
1
,
5
, O. Reula
82
,
F. Ricci
24
,
74
, K. Riles
64
, N. A. Robertson
1
,
31
, R. Robie
31
, F. Robinet
44
, A. Rocchi
65
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1
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2
Louisiana State University, Baton Rouge, LA 70803, USA
3
Università di Salerno, Fisciano, I-84084 Salerno, Italy
4
INFN, Sezione di Napoli, Complesso Universitario di Monte Sant
Angelo, I-80126 Napoli, Italy
5
University of Florida, Gainesville, FL 32611, USA
6
LIGO Livingston Observatory, Livingston, LA 70754, USA
7
Cardiff University, Cardiff, CF24 3AA, UK
8
Laboratoire d
Annecy-le-Vieux de Physique des Particules
(
LAPP
)
, Université de Savoie, 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
Experimental Group, Albert-Einstein-Institut, Max-Planck-Institut für 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 São José dos Campos, SP, Brazil
14
Inter-University Centre for Astronomy and Astrophysics, Pune 411007, India
15
International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bangalore 560012, India
16
Syracuse University, Syracuse, NY 13244, USA
17
Data Analysis Group, Albert-Einstein-Institut, Max-Planck-Institut für Gravitationsphysik, D-30167 Hannover, Germany
18
University of Wisconsin
Milwaukee, Milwaukee, WI 53201, USA
19
Università di Siena, I-53100 Siena, Italy
20
INFN, Sezione di Pisa, I-56127 Pisa, Italy
21
The University of Mississippi, University, MS 38677, USA
22
California State University Fullerton, Fullerton, CA 92831, USA
23
Leibniz Universität Hannover, D-30167 Hannover, Germany
24
INFN, Sezione di Roma, I-00185 Roma, Italy
25
University of Birmingham, Birmingham, B15 2TT, UK
26
Albert-Einstein-Institut, Max-Planck-Institut für Gravitationsphysik, D-14476 Golm, Germany
27
Montana State University, Bozeman, MT 59717, USA
28
Università di Perugia, I-06123 Perugia, Italy
29
INFN, Sezione di Perugia, I-06123 Perugia, Italy
30
European Gravitational Observatory
(
EGO
)
, I-56021 Cascina, Pisa, Italy
31
SUPA, University of Glasgow, Glasgow, G12 8QQ, UK
32
LIGO Hanford Observatory, Richland, WA 99352, USA
33
APC, AstroParticule et Cosmologie, Université Paris Diderot, CNRS
/
IN2P3, CEA
/
Irfu, Observatoire de Paris,
Sorbonne Paris Cité, 10, rue Alice Domon et Léonie Duquet, F-75205 Paris Cedex 13, France
34
Columbia University, New York, NY 10027, USA
35
Stanford University, Stanford, CA 94305, USA
36
Università di Pisa, I-56127 Pisa, Italy
37
CAMK-PAN, 00-716 Warsaw, Poland
38
Astronomical Observatory Warsaw University, 00-478 Warsaw, Poland
39
The University of Texas at Brownsville, Brownsville, TX 78520, USA
40
Università degli Studi di Genova, I-16146 Genova, Italy
41
INFN, Sezione di Genova, I-16146 Genova, Italy
42
RRCAT, Indore MP 452013, India
43
Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia
44
LAL, Université Paris-Sud, IN2P3
/
CNRS, F-91898 Orsay, France
45
NASA
/
Goddard Space Flight Center, Greenbelt, MD 20771, USA
46
University of Western Australia, Crawley, WA 6009, Australia
47
Department of Astrophysics
/
IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands
48
ARTEMIS, Université Nice-Sophia-Antipolis, CNRS and Observatoire de la Côte d
Azur, F-06304 Nice, France
49
MTA Eötvös University,
Lendulet
Astrophysics Research Group, Budapest 1117, Hungary
50
Institut de Physique de Rennes, CNRS, Université de Rennes 1, F-35042 Rennes, France
51
Washington State University, Pullman, WA 99164, USA
52
Università degli Studi di Urbino
Carlo Bo,
I-61029 Urbino, Italy
53
INFN, Sezione di Firenze, I-50019 Sesto Fiorentino, Firenze, Italy
54
University of Oregon, Eugene, OR 97403, USA
55
Laboratoire Kastler Brossel, ENS, CNRS, UPMC, Université Pierre et Marie Curie, F-75005 Paris, France
56
VU University Amsterdam, 1081 HV Amsterdam, The Netherlands
57
University of Maryland, College Park, MD 20742, USA
58
University of Massachusetts Amherst, Amherst, MA 01003, USA
59
Laboratoire des Matériaux Avancés
(
LMA
)
, IN2P3
/
CNRS, Université de Lyon, F-69622 Villeurbanne, Lyon, France
60
Universitat de les Illes Balears
IEEC, E-07122 Palma de Mallorca, Spain
61
Università di Napoli
Federico II,
Complesso Universitario di Monte Sant
Angelo, I-80126 Napoli, Italy
62
Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, Ontario, M5S 3H8, Canada
63
Tsinghua University, Beijing 100084, China
64
University of Michigan, Ann Arbor, MI 48109, USA
65
INFN, Sezione di Roma Tor Vergata, I-00133 Roma, Italy
66
National Tsing Hua University, Hsinchu Taiwan 300
67
Charles Sturt University, Wagga Wagga, NSW 2678, Australia
68
Caltech-CaRT, Pasadena, CA 91125, USA
69
Pusan National University, Busan 609-735, Korea
70
Australian National University, Canberra, ACT 0200, Australia
71
Carleton College, North
fi
eld, MN 55057, USA
72
Università di Roma Tor Vergata, I-00133 Roma, Italy
73
INFN, Gran Sasso Science Institute, I-67100 L
Aquila, Italy
3
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)
, 2015 November 1
Aasi et al.
74
Università di Roma
La Sapienza,
I-00185 Roma, Italy
75
University of Brussels, Brussels 1050, Belgium
76
Sonoma State University, Rohnert Park, CA 94928, USA
77
Texas Tech University, Lubbock, TX 79409, USA
78
University of Minnesota, Minneapolis, MN 55455, USA
79
The University of Shef
fi
eld, Shef
fi
eld S10 2TN, UK
80
Wigner RCP, RMKI, H-1121 Budapest, Konkoly Thege Miklós út 29-33, Hungary
81
Montclair State University, Montclair, NJ 07043, USA
82
Argentinian Gravitational Wave Group, Cordoba Cordoba 5000, Argentina
83
Università di Trento, I-38123 Povo, Trento, Italy
84
INFN, Trento Institute for Fundamental Physics and Applications, I-38123 Povo, Trento, Italy
85
Northwestern University, Evanston, IL 60208, USA
86
University of Cambridge, Cambridge, CB2 1TN, UK
87
University of Szeged, Dóm tér 9, Szeged 6720, Hungary
88
Rutherford Appleton Laboratory, HSIC, Chilton, Didcot, Oxon, OX11 0QX, UK
89
Embry-Riddle Aeronautical University, Prescott, AZ 86301, USA
90
The Pennsylvania State University, University Park, PA 16802, USA
91
American University, Washington, DC 20016, USA
92
University of Adelaide, Adelaide, SA 5005, Australia
93
West Virginia University, Morgantown, WV 26506, USA
94
Raman Research Institute, Bangalore, Karnataka 560080, India
95
Korea Institute of Science and Technology Information, Daejeon 305-806, Korea
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SUPA, University of Strathclyde, Glasgow, G1 1XQ, UK
98
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99
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100
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Ś
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104
IM-PAN, 00-956 Warsaw, Poland
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Institute for Plasma Research, Bhat, Gandhinagar 382428, India
106
The University of Melbourne, Parkville, VIC 3010, Australia
107
INFN, Sezione di Padova, I-35131 Padova, Italy
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Monash University, Victoria 3800, Australia
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ESPCI, CNRS, F-75005 Paris, France
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Università di Camerino, Dipartimento di Fisica, I-62032 Camerino, Italy
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Southern University and A&M College, Baton Rouge, LA 70813, USA
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College of William and Mary, Williamsburg, VA 23187, USA
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São Paulo SP 01140-070, Brazil
115
IISER-Kolkata, Mohanpur, West Bengal 741252, India
116
Whitman College, 280 Boyer Avenue, Walla Walla, WA 9936, USA
117
National Institute for Mathematical Sciences, Daejeon 305-390, Korea
118
Rochester Institute of Technology, Rochester, NY 14623, USA
119
Hobart and William Smith Colleges, Geneva, NY 14456, USA
120
Tata Institute for Fundamental Research, Mumbai 400005, India
121
SUPA, University of the West of Scotland, Paisley, PA1 2BE, UK
122
Institute of Astronomy, 65-265 Zielona Góra, Poland
123
Universität Hamburg, D-22761 Hamburg, Germany
124
Indian Institute of Technology, Gandhinagar Ahmedabad Gujarat 382424, India
125
Andrews University, Berrien Springs, MI 49104, USA
126
Trinity University, San Antonio, TX 78212, USA
127
University of Washington, Seattle, WA 98195, USA
Received 2015 January 17; accepted 2015 September 18; published 2015 October 27
ABSTRACT
We describe directed searches for continuous gravitational waves
(
GWs
)
in data from the sixth Laser
Interferometer Gravitational-wave Observatory
(
LIGO
)
science data run. The targets were nine young supernova
remnants not associated with pulsars; eight of the remnants are associated with non-pulsing suspected neutron
stars. One target
ʼ
s parameters are uncertain enough to warrant two searches, for a total of 10. Each search covered a
broad band of frequencies and
fi
rst and second frequency derivatives for a
fi
xed sky direction. The searches
coherently integrated data from the two LIGO interferometers over time spans from 5.3
25.3 days using the
matched-
fi
ltering
-statistic. We found no evidence of GW signals. We set 95% con
fi
dence upper limits as strong
(
low
)
as 4
×
10
25
on intrinsic strain, 2
×
10
7
on
fi
ducial ellipticity, and 4
×
10
5
on
r
-mode amplitude. These
beat the indirect limits from energy conservation and are within the range of theoretical predictions for neutron-star
ellipticities and
r
-mode amplitudes.
Key words:
gravitational waves
ISM: supernova remnants
stars: neutron
Supporting material:
machine-readable table
4
The Astrophysical Journal,
813:39
(
16pp
)
, 2015 November 1
Aasi et al.
1. INTRODUCTION
Young neutron stars are attractive targets for searches for
continuous gravitational waves
(
GWs
)
even if they are not
detected as pulsars
(
Wette et al.
2008
; Owen
2009
; Abadie
et al.
2010
)
. Some are seen as non-pulsing central compact
objects
(
CCOs
)
in supernova remnants
(
SNRs
)
, and some
young pulsar wind nebulas
(
PWNs
)
and SNRs indicate the
location of a young neutron star with enough precision for a
directed search
a search over frequency and spin-down
parameters, but not over sky positions. Some young pulsars
spin fast enough to emit GWs in the frequency band of ground-
based interferometers such as the Laser Interferometer
Gravitational-wave Observatory
(
LIGO
)
and Virgo, and there-
fore some young non-pulsars may also spin fast enough. Even
without observed pulsations and spin-down parameters, it is
possible to estimate an indirect upper limit on GW emission,
analogous to the spin-down limit
(
Shklovskii
1969
)
for known
pulsars, based on the age of and distance to the star plus energy
conservation
(
Wette et al.
2008
)
. Given the great uncertainties
in predictions of GW emission from young neutron stars, we
use this indirect limit rather than those predictions to pick
targets for directed searches.
We describe such searches of data from the sixth LIGO
science run
(
S6
)
for continuous GWs from Cas A and eight
more SNRs with known or suspected young isolated neutron
stars with no observed electromagnetic pulsations. These
targets were chosen so that a computationally feasible coherent
search similar to Abadie et al.
(
2010
)
could beat the indirect
limits on GW emission. Therefore, each search had a chance of
detecting something, and non-detections could constrain the
star
ʼ
s GW emission, provided that emission is at a frequency in
the band searched. No search found evidence for a GW signal,
and hence the main result is a set of upper limits similar to
those presented in Abadie et al.
(
2010
)
. These upper limits on
GW emission translate into upper limits on the
fi
ducial
ellipticity and
r
-mode amplitude of each neutron star as a
function of GW frequency the star could be emitting
(
see
Section
3.2
)
. The ellipticity and
r
-mode upper limits set by the
searches described here were within the ranges of theoretical
predictions
(
Bondarescu et al.
2009
; Johnson-McDaniel
2013
)
,
another indicator that these searches reached interesting
sensitivities
(
see Section
4
)
.
For context, we compare to the other continuous GW
searches, which correspond to three other astronomical
populations that nonetheless share astrophysical emission
mechanisms and other properties
(
Owen
2009
)
. Directed
searches occupy a middle ground between all-sky searches
and targeted searches for known pulsars in the key trade-off for
continuous waves: searches with greater sensitivity and less
computational cost require more astronomical information, and
have different indirect limits to beat to reach an interesting
sensitivity.
The
fi
rst search for continuous waves in LIGO data, from its
fi
rst science run
(
S1
)
, was for a single known pulsar
(
Abbott
et al.
2004
)
. Such a search, guided by a precise timing solution,
is computationally cheap and achieves the best strain sensitivity
for a given amount of data since all available data can be
integrated coherently. Since then, searches of data up to S6
have targeted up to 195 pulsars
(
Abbott et al.
2005b
,
2007c
,
2008b
,
2010
; Abadie et al.
2011a
; Aasi et al.
2014c
)
. The four
most recent of these papers set direct upper limits on GW
emission stricter than the spin-down limits derived from energy
conservation, for a few of the pulsars searched, thereby
marking the point at which LIGO and Virgo began revealing
new information about these pulsars. The upper limits also
corresponded to neutron-star ellipticities within the range
of theoretical predictions for exotic equations of state
(
Owen
2005
)
.
Other continuous GW searches have surveyed the whole sky
for neutron stars not seen as pulsars, using great computational
power to cover wide frequency bands and large ranges of spin-
down parameters
(
Abbott et al.
2005a
,
2007a
,
2008a
,
2009a
,
2009b
,
2009c
; Abadie et al.
2012
; Aasi et al.
2013b
,
2014a
,
2014d
)
and recently possible binary parameters too
(
Aasi
et al.
2014b
)
. Several of the recent all-sky searches have set
direct upper limits competitive with indirect upper limits based
on simulations of the galactic neutron-star population
(
Knispel
& Allen
2008
)
.
Between these two extremes of computational cost and
sensitivity are the directed searches, where the sky location
(
and thus the detector-frame Doppler modulation
)
is known but
the frequency and other parameters are not. Directed searches
can be divided further into searches for isolated neutron stars
(
the type of search described in this paper
)
, and searches for
neutron stars in binary systems, with particular emphasis on
accreting neutron stars in close
(
low-mass X-ray
)
binaries. For
accreting neutron stars, a different indirect limit can be set
based on angular momentum conservation
(
Papaloizou &
Pringle
1978
)
. Unlike the energy conservation-based indirect
limits for other neutron star populations, there is an argument
(
partially based on observations
)
that accreting neutron stars
emit close to their limit, which also corresponds to reasonable
ellipticities and
r
-mode amplitudes
(
Bildsten
1998
)
. So far the
only accreting neutron star targeted has been the one in the
low-mass X-ray binary Sco X-1
(
Abbott et al.
2007a
,
2007b
;
Abadie et al.
2011b
; Aasi et al.
2015c
)
. Searches for this object
must cover not only a range of GW frequencies since no
pulsations are observed, but also a range of orbital parameters
since there are substantial uncertainties in these. Direct upper
limits from searches for Sco X-1 have not beaten the indirect
limit derived from accretion torque balance
(
Papaloizou &
Pringle
1978
)
, but may with data from interferometers
upgraded to the
advanced
sensitivity
(
Harry
2010
; Sammut
et al.
2014
; Aasi et al.
2015a
)
.
The type of directed search described here, for isolated
neutron stars not seen as pulsars, was
fi
rst performed on data
from the
fi
fth LIGO science run
(
S5
)
for the CCO in the SNR
Cas A
(
Abadie et al.
2010
)
. Since then, similar searches, using
different data analysis methods, have been performed for
supernova 1987A and unseen stars near the galactic center
(
Abadie et al.
2011b
; Aasi et al.
2013a
)
. Directed searches for
isolated neutron stars are intermediate in cost and sensitivity
between targeted pulsar searches and all-sky searches because a
known sky direction allows for searching a wide band of
frequencies and frequency derivatives with much less comput-
ing power than the all-sky wide-band searches
(
Wette
et al.
2008
)
and no search over binary parameters is needed.
The indirect limits to beat are numerically similar to those for
known pulsars
the strain limit for Cas A is almost identical to
that for the Crab pulsar. One disadvantage of this type of search
compared to pulsar searches is that the spin frequencies of the
neutron stars are not known. Based on pulsar statistics, it is
5
The Astrophysical Journal,
813:39
(
16pp
)
, 2015 November 1
Aasi et al.
likely that most of these stars are not spinning fast enough to be
emitting GWs in the detectable frequency band, making it all
the more important to search multiple targets. Here we improve
the methods of the S5 Cas A search
(
Abadie et al.
2010
)
and
extend our search targets to nine young SNRs total.
The rest of this article is structured as follows. In Section
2
,
we present the methods, implementation, and results of the
searches. The upper limits set in the absence of evidence for a
signal are presented in Section
3
, and the results are discussed
in Section
4
. In the
appendix
, we describe the performance of
the analysis pipeline on hardware injected signals.
2. SEARCHES
2.1. Data Selection
S6 ran from 2009 July 7 21:00:00 UTC
(
GPS 931035615
)
to
2010 October 21 00:00:00 UTC
(
GPS 971654415
)
. It included
two interferometers with 4-km arm lengths, H1 at LIGO
Hanford Observatory
(
LHO
)
near Hanford, Washington and L1
at LIGO Livingston Observatory
(
LLO
)
near Livingston,
Louisiana. It did not include the 2-km H2 interferometer that
was present at LHO during earlier runs. Plots of the noise
power spectral density
(
PSD
)
curves and descriptions of the
improvements over S5 can be found, for example, in Aasi et al.
(
2015b
)
. A description of the calibration and uncertainties can
be found in Bartos et al.
(
2011
)
. The phase calibration errors at
the frequencies searched were up to
7
and 10
for H1 and L1,
respectively, small enough not to affect the analysis. The
corresponding amplitude calibration errors were 16% and 19%
respectively. For reasons discussed in Aasi et al.
(
2014c
)
,we
estimate the maximum amplitude uncertainty of our joint H1-
L1 results to be 20%.
Concurrently with the LIGO S6 run, the Virgo interferometer
near Cascina, Italy had its data runs VSR2 and VSR3.
Although Virgo noise performance was better than LIGO in
a narrow band below roughly 40 Hz, it was worse than LIGO
by a factor of two to three in amplitude at the higher
frequencies of the searches described here. Virgo
ʼ
s declination
response function for many-day observations averaged over
inclinations and polarizations is within about 10% of that of
LHO, and even extreme inclinations and polarizations are not
too far from average
(
see Figure 4 and Equation
(
86
)
,
respectively, of Jaranowski et al.
1998
)
. Hence Virgo
ʼ
s
single-interferometer sensitivity is worse by a factor of two
to three in amplitude, and since the signal-to-noise is added in
quadrature between interferometers, the addition of Virgo
would enhance the sensitivity to a typical source by at most a
few percent
much less than the LIGO calibration uncertainty.
Since data analysis costs the same for all interferometers and
computational resources are limited, the searches described
here only used LIGO data.
Like many other continuous-wave searches, those reported
here used GW data in the Short Fourier Transform
(
SFT
)
format. The series of science-mode data, interrupted by planned
(
maintenance
)
and unplanned downtime
(
earthquakes, etc.
)
,
minus short segments which were
category 1
vetoed
(
Aasi
et al.
2015b
)
, was broken into segments of
=
T
1800 s.
SFT
There were a total of 19,268 of these segments for H1 and L1
during the S6 run. Each 30-minute segment was
fi
rst high pass
fi
ltered in the time domain through a tenth-order Butterworth
fi
lter with a knee frequency of 30 Hz to attenuate low-
frequency seismic noise. Then it was Tukey windowed with
parameter 0.001
(
i.e., only 0.1% of samples were modi
fi
ed
)
to
mitigate edge artifacts. Finally, each segment was Fourier
transformed and frequencies from 40
2035 Hz were recorded
in the corresponding SFT.
Although a directed search is computationally more tractable
than an all-sky search, computational costs nonetheless
restricted us to searching a limited time span
T
span
of the S6
data. This span, and the frequency band
f
min
f
max
, were
determined for each target by an algorithm designed to
fi
x the
computational cost per target as described in Section
2.4
. The
data selection criterion was the same as in Abadie et al.
(
2010
)
,
maximizing the
fi
gure of merit
å
Sft
1
,
1
ft
h
,
()
()
where the sums run over the given
T
span
,
f
min
, and
f
max
for each
target. Here
f
is the frequency of each bin
(
discretized at
T
1
SFT
)
,
t
is the time stamp of each SFT, and
S
h
is the strain
noise PSD harmonically averaged over the H1 and L1
interferometers. Maximizing this
fi
gure of merit roughly
corresponds to optimizing
(
minimizing
)
the detectable GW
strain, harmonically averaged over the frequency band.
Although the frequency band for each search varied target by
target, the sum was dominated by the least noisy frequencies
that are searched for all targets, and thus the optimization
always picked time spans near the end of S6 when the noise at
those frequencies was best
(
least
)
and the SFT duty factor
(
total
SFT time divided by
T
span
divided by numbers of interferom-
eters
[
two
]
)
was highest. This
fi
gure of merit also neglects the
small effect where LHO is better for high declination sources
and LLO is better for low
(
Jaranowski et al.
1998
)
. Since the
optimal data stretches tended to have comparable amounts of
H1 and L1 data, the declination effect was at most a few
percent, less than the amplitude calibration uncertainties.
2.2. Analysis Method
The analysis was based on matched
fi
ltering, the optimal
method for detecting signals of known functional form. To
obtain that form, we assumed that the instantaneous frequency
of the continuous
(
sinusoidal
)
GWs in the solar system
barycenter was
+-+ -
ft fftt ftt
1
2
.2
00
2
()
̇
()
̈
()
()
That is, we assumed that none of the target neutron stars
glitched
(
had abrupt frequency jumps
)
or had signi
fi
cant timing
noise
(
additional, perhaps stochastic, time dependence of the
frequency
)
during the observation. We also neglected third and
higher derivatives of the GW frequency, based on the time
spans and ranges of
f
̇
and
f
̈
covered. The precise expression
for the interferometer strain response
ht
()
to an incoming
continuous GW also includes amplitude and phase modulation
by the changing of the beam patterns as the interferometer
rotates with the Earth. It depends on the source
ʼ
s sky location
and orientation angles, as well as on the parameters of the
interferometer, and takes the form of four sinusoids. We do not
reproduce the lengthy expression here, but it can be found in
Jaranowski et al.
(
1998
)
.
6
The Astrophysical Journal,
813:39
(
16pp
)
, 2015 November 1
Aasi et al.