Search for post-merger gravitational waves from the remnant of the binary neutron star merger GW170817

In Advanced LIGO, detection and astrophysical source parameter estimation of the binary black hole merger GW150914 requires a calibrated estimate of the gravitational-wave strain sensed by the detectors. Producing an estimate from each detector's differential arm length control loop readout signals requires applying time domain filters, which are designed from a frequency domain model of the detector's gravitational-wave response. The gravitational-wave response model is determined by the detector's opto-mechanical response and the properties of its feedback control system. The measurements used to validate the model and characterize its uncertainty are derived primarily from a dedicated photon radiation pressure actuator, with cross-checks provided by optical and radio frequency references. We describe how the gravitational-wave readout signal is calibrated into equivalent gravitational-wave-induced strain and how the statistical uncertainties and systematic errors are assessed. Detector data collected over 38 calendar days, from September 12 to October 20, 2015, contain the event GW150914 and approximately 16 of coincident data used to estimate the event false alarm probability. The calibration uncertainty is less than 10% in magnitude and 10 degrees in phase across the relevant frequency band 20 Hz to 1 kHz

First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

In Advanced LIGO, detection and astrophysical source parameter estimation of the binary black hole merger GW150914 requires a calibrated estimate of the gravitational-wave strain sensed by the detectors. Producing an estimate from each detector's differential arm length control loop readout signals requires applying time domain filters, which are designed from a frequency domain model of the detector's gravitational-wave response. The gravitational-wave response model is determined by the detector's opto-mechanical response and the properties of its feedback control system. The measurements used to validate the model and characterize its uncertainty are derived primarily from a dedicated photon radiation pressure actuator, with cross-checks provided by optical and radio frequency references. We describe how the gravitational-wave readout signal is calibrated into equivalent gravitational-wave-induced strain and how the statistical uncertainties and systematic errors are assessed. Detector data collected over 38 calendar days, from September 12 to October 20, 2015, contain the event GW150914 and approximately 16 of coincident data used to estimate the event false alarm probability. The calibration uncertainty is less than 10% in magnitude and 10 degrees in phase across the relevant frequency band 20 Hz to 1 kHz

All-sky search for long-duration gravitational wave transients in the first Advanced LIGO observing run

We present the results of a search for long-duration gravitational wave transients in the data of the LIGO Hanford and LIGO Livingston second generation detectors between September 2015 and January 2016 , with a total observational time of 49 d. The search targets gravitational wave transients of 10 – 500 s duration in a frequency band of 24 – 2048 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. No significant events were observed. As a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. We also show that the search is sensitive to sources in the Galaxy emitting at least ∼ 10 − 8 M c 2 in gravitational waves

Effects of waveform model systematics on the interpretation of GW150914

PAPER Effects of waveform model systematics on the interpretation of GW150914 B P Abbott1, R Abbott1, T D Abbott2, M R Abernathy3, F Acernese4,5, K Ackley6, C Adams7, T Adams8, P Addesso9,144, R X Adhikari1, V B Adya10, C Affeldt10, M Agathos11, K Agatsuma11, N Aggarwal12, O D Aguiar13, L Aiello14,15, A Ain16, P Ajith17, B Allen10,18,19, A Allocca20,21, P A Altin22, A Ananyeva1, S B Anderson1, W G Anderson18, S Appert1, K Arai1, M C Araya1, J S Areeda23, N Arnaud24, K G Arun25, S Ascenzi15,26, G Ashton10, M Ast27, S M Aston7, P Astone28, P Aufmuth19, C Aulbert10, A Avila-Alvarez23, S Babak29, P Bacon30, M K M Bader11, P T Baker31, F Baldaccini32,33, G Ballardin34, S W Ballmer35, J C Barayoga1, S E Barclay36, B C Barish1, D Barker37, F Barone4,5, B Barr36, L Barsotti12, M Barsuglia30, D Barta38, J Bartlett37, I Bartos39, R Bassiri40, A Basti20,21, J C Batch37, C Baune10, V Bavigadda34, M Bazzan41,42, C Beer10, M Bejger43, I Belahcene24, M Belgin44, A S Bell36, B K Berger1, G Bergmann10, C P L Berry45, D Bersanetti46,47, A Bertolini11, J Betzwieser7, S Bhagwat35, R Bhandare48, I A Bilenko49, G Billingsley1, C R Billman6, J Birch7, R Birney50, O Birnholtz10, S Biscans1,12, A Bisht19, M Bitossi34, C Biwer35, M A Bizouard24, J K Blackburn1, J Blackman51, C D Blair52, D G Blair52, R M Blair37, S Bloemen53, O Bock10, M Boer54, G Bogaert54, A Bohe29, F Bondu55, R Bonnand8, B A Boom11, R Bork1, V Boschi20,21, S Bose16,56, Y Bouffanais30, A Bozzi34, C Bradaschia21, P R Brady18, V B Braginsky49,145, M Branchesi57,58, J E Brau59, T Briant60, A Brillet54, M Brinkmann10, V Brisson24, P Brockill18, J E Broida61, A F Brooks1, D A Brown35, D D Brown45, N M Brown12, S Brunett1, C C Buchanan2, A Buikema12, T Bulik62, H J Bulten11,63, A Buonanno29,64, D Buskulic8, C Buy30, R L Byer40, M Cabero10, L Cadonati44, G Cagnoli65,66, C Cahillane1, J Calderón Bustillo44, T A Callister1, E Calloni5,67, J B Camp68, K C Cannon69, H Cao70, J Cao71, C D Capano10, E Capocasa30, F Carbognani34, S Caride72, J Casanueva Diaz24, C Casentini15,26, S Caudill18, M Cavaglià73, F Cavalier24, R Cavalieri34, G Cella21, C B Cepeda1, L Cerboni Baiardi57,58, G Cerretani20,21, E Cesarini15,26, S J Chamberlin74, M Chan36, S Chao75, P Charlton76, E Chassande-Mottin30, B D Cheeseboro31, H Y Chen77, Y Chen51, H-P Cheng6, A Chincarini47, A Chiummo34, T Chmiel78, H S Cho79, M Cho64, J H Chow22, N Christensen61, Q Chu52, A J K Chua80, S Chua60, S Chung52, G Ciani6, F Clara37, J A Clark44, F Cleva54, C Cocchieri73, E Coccia14,15, P-F Cohadon60, A Colla28,81, C G Collette82, L Cominsky83, M Constancio Jr13, L Conti42, S J Cooper45, T R Corbitt2, N Cornish84, A Corsi72, S Cortese34, C A Costa13, M W Coughlin61, S B Coughlin85, J-P Coulon54, S T Countryman39, P Couvares1, P B Covas86, E E Cowan44, D M Coward52, M J Cowart7, D C Coyne1, R Coyne72, J D E Creighton18, T D Creighton87, J Cripe2, S G Crowder88, T J Cullen23, A Cumming36, L Cunningham36, E Cuoco34, T Dal Canton68, S L Danilishin36, S D'Antonio15, K Danzmann10,19, A Dasgupta89, C F Da Silva Costa6, V Dattilo34, I Dave48, M Davier24, G S Davies36, D Davis35, E J Daw90, B Day44, R Day34, S De35, D DeBra40, G Debreczeni38, J Degallaix65, M De Laurentis5,67, S Deléglise60, W Del Pozzo45, T Denker10, T Dent10, V Dergachev29, R De Rosa5,67, R T DeRosa7, R DeSalvo91, J Devenson50, R C Devine31, S Dhurandhar16, M C Díaz87, L Di Fiore5, M Di Giovanni92,93, T Di Girolamo5,67, A Di Lieto20,21, S Di Pace28,81, I Di Palma28,29,81, A Di Virgilio21, Z Doctor77, V Dolique65, F Donovan12, K L Dooley73, S Doravari10, I Dorrington94, R Douglas36, M Dovale Álvarez45, T P Downes18, M Drago10, R W P Drever1,146, J C Driggers37, Z Du71, M Ducrot8, S E Dwyer37, T B Edo90, M C Edwards61, A Effler7, H-B Eggenstein10, P Ehrens1, J Eichholz1, S S Eikenberry6, R A Eisenstein12, R C Essick12, Z Etienne31, T Etzel1, M Evans12, T M Evans7, R Everett74, M Factourovich39, V Fafone14,15,26, H Fair35, S Fairhurst94, X Fan71, S Farinon47, B Farr77, W M Farr45, E J Fauchon-Jones94, M Favata95, M Fays94, H Fehrmann10, M M Fejer40, A Fernández Galiana12, I Ferrante20,21, E C Ferreira13, F Ferrini34, F Fidecaro20,21, I Fiori34, D Fiorucci30, R P Fisher35, R Flaminio65,96, M Fletcher36, H Fong97, S S Forsyth44, J-D Fournier54, S Frasca28,81, F Frasconi21, Z Frei98, A Freise45, R Frey59, V Frey24, E M Fries1, P Fritschel12, V V Frolov7, P Fulda6,68, M Fyffe7, H Gabbard10, B U Gadre16, S M Gaebel45, J R Gair99, L Gammaitoni32, S G Gaonkar16, F Garufi5,67, G Gaur100, V Gayathri101, N Gehrels68, G Gemme47, E Genin34, A Gennai21, J George48, L Gergely102, V Germain8, S Ghonge17, Abhirup Ghosh17, Archisman Ghosh11,17, S Ghosh11,53, J A Giaime2,7, K D Giardina7, A Giazotto21, K Gill103, A Glaefke36, E Goetz10, R Goetz6, L Gondan98, G González2, J M Gonzalez Castro20,21, A Gopakumar104, M L Gorodetsky49, S E Gossan1, M Gosselin34, R Gouaty8, A Grado5,105, C Graef36, M Granata65, A Grant36, S Gras12, C Gray37, G Greco57,58, A C Green45, P Groot53, H Grote10, S Grunewald29, G M Guidi57,58, X Guo71, A Gupta16, M K Gupta89, K E Gushwa1, E K Gustafson1, R Gustafson106, J J Hacker23, B R Hall56, E D Hall1, G Hammond36, M Haney104, M M Hanke10, J Hanks37, C Hanna74, M D Hannam94, J Hanson7, T Hardwick2, J Harms57,58, G M Harry3, I W Harry29, M J Hart36, M T Hartman6, C-J Haster45,97, K Haughian36, J Healy107, A Heidmann60, M C Heintze7, H Heitmann54, P Hello24, G Hemming34, M Hendry36, I S Heng36, J Hennig36, J Henry107, A W Heptonstall1, M Heurs10,19, S Hild36, D Hoak34, D Hofman65, K Holt7, D E Holz77, P Hopkins94, J Hough36, E A Houston36, E J Howell52, Y M Hu10, E A Huerta108, D Huet24, B Hughey103, S Husa86, S H Huttner36, T Huynh-Dinh7, N Indik10, D R Ingram37, R Inta72, H N Isa36, J-M Isac60, M Isi1, T Isogai12, B R Iyer17, K Izumi37, T Jacqmin60, K Jani44, P Jaranowski109, S Jawahar110, F Jiménez-Forteza86, W W Johnson2, D I Jones111, R Jones36, R J G Jonker11, L Ju52, J Junker10, C V Kalaghatgi94, V Kalogera85, S Kandhasamy73, G Kang79, J B Kanner1, S Karki59, K S Karvinen10, M Kasprzack2, E Katsavounidis12, W Katzman7, S Kaufer19, T Kaur52, K Kawabe37, F Kéfélian54, D Keitel86, D B Kelley35, R Kennedy90, J S Key112, F Y Khalili49, I Khan14, S Khan94, Z Khan89, E A Khazanov113, N Kijbunchoo37, Chunglee Kim114, J C Kim115, Whansun Kim116, W Kim70, Y-M Kim114,117, S J Kimbrell44, E J King70, P J King37, R Kirchhoff10, J S Kissel37, B Klein85, L Kleybolte27, S Klimenko6, P Koch10, S M Koehlenbeck10, S Koley11, V Kondrashov1, A Kontos12, M Korobko27, W Z Korth1, I Kowalska62, D B Kozak1, C Krämer10, V Kringel10, B Krishnan10, A Królak118,119, G Kuehn10, P Kumar97, R Kumar89, L Kuo75, A Kutynia118, B D Lackey29,35, M Landry37, R N Lang18, J Lange107, B Lantz40, R K Lanza12, A Lartaux-Vollard24, P D Lasky120, M Laxen7, A Lazzarini1, C Lazzaro42, P Leaci28,81, S Leavey36, E O Lebigot30, C H Lee117, H K Lee121, H M Lee114, K Lee36, J Lehmann10, A Lenon31, M Leonardi92,93, J R Leong10, N Leroy24, N Letendre8, Y Levin120, T G F Li122, A Libson12, T B Littenberg123, J Liu52, N A Lockerbie110, A L Lombardi44, L T London94, J E Lord35, M Lorenzini14,15, V Loriette124, M Lormand7, G Losurdo21, J D Lough10,19, G Lovelace23, H Lück10,19, A P Lundgren10, R Lynch12, Y Ma51, S Macfoy50, B Machenschalk10, M MacInnis12, D M Macleod2, F Magaña-Sandoval35, E Majorana28, I Maksimovic124, V Malvezzi15,26, N Man54, V Mandic125, V Mangano36, G L Mansell22, M Manske18, M Mantovani34, F Marchesoni33,126, F Marion8, S Márka39, Z Márka39, A S Markosyan40, E Maros1, F Martelli57,58, L Martellini54, I W Martin36, D V Martynov12, K Mason12, A Masserot8, T J Massinger1, M Masso-Reid36, S Mastrogiovanni28,81, F Matichard1,12, L Matone39, N Mavalvala12, N Mazumder56, R McCarthy37, D E McClelland22, S McCormick7, C McGrath18, S C McGuire127, G McIntyre1, J McIver1, D J McManus22, T McRae22, S T McWilliams31, D Meacher54,74, G D Meadors10,29, J Meidam11, A Melatos128, G Mendell37, D Mendoza-Gandara10, R A Mercer18, E L Merilh37, M Merzougui54, S Meshkov1, C Messenger36, C Messick74, R Metzdorff60, P M Meyers125, F Mezzani28,81, H Miao45, C Michel65, H Middleton45, E E Mikhailov129, L Milano5,67, A L Miller6,28,81, A Miller85, B B Miller85, J Miller12, M Millhouse84, Y Minenkov15, J Ming29, S Mirshekari130, C Mishra17, S Mitra16, V P Mitrofanov49, G Mitselmakher6, R Mittleman12, A Moggi21, M Mohan34, S R P Mohapatra12, M Montani57,58, B C Moore95, C J Moore80, D Moraru37, G Moreno37, S R Morriss87, B Mours8, C M Mow-Lowry45, G Mueller6, A W Muir94, Arunava Mukherjee17, D Mukherjee18, S Mukherjee87, N Mukund16, A Mullavey7, J Munch70, E A M Muniz23, P G Murray36, A Mytidis6, K Napier44, I Nardecchia15,26, L Naticchioni28,81, G Nelemans11,53, T J N Nelson7, M Neri46,47, M Nery10, A Neunzert106, J M Newport3, G Newton36, T T Nguyen22, A B Nielsen10, S Nissanke11,53, A Nitz10, A Noack10, F Nocera34, D Nolting7, M E N Normandin87, L K Nuttall35, J Oberling37, E Ochsner18, E Oelker12, G H Ogin131, J J Oh116, S H Oh116, F Ohme10,94, M Oliver86, P Oppermann10, Richard J Oram7, B O'Reilly7, R O'Shaughnessy107, D J Ottaway70, H Overmier7, B J Owen72, A E Pace74, J Page123, A Pai101, S A Pai48, J R Palamos59, O Palashov113, C Palomba28, A Pal-Singh27, H Pan75, C Pankow85, F Pannarale94, B C Pant48, F Paoletti21,34, A Paoli34, M A Papa10,18,29, H R Paris40, W Parker7, D Pascucci36, A Pasqualetti34, R Passaquieti20,21, D Passuello21, B Patricelli20,21, B L Pearlstone36, M Pedraza1, R Pedurand65,132, L Pekowsky35, A Pele7, S Penn133, C J Perez37, A Perreca1, L M Perri85, H P Pfeiffer97, M Phelps36, O J Piccinni28,81, M Pichot54, F Piergiovanni57,58, V Pierro9, G Pillant34, L Pinard65, I M Pinto9, M Pitkin36, M Poe18, R Poggiani20,21, P Popolizio34, A Post10, J Powell36, J Prasad16, J W W Pratt103, V Predoi94, T Prestegard18,125, M Prijatelj10,34, M Principe9, S Privitera29, G A Prodi92,93, L G Prokhorov49, O Puncken10, M Punturo33, P Puppo28, M Pürrer29, H Qi18, J Qin52, S Qiu120, V Quetschke87, E A Quintero1, R Quitzow-James59, F J Raab37, D S Rabeling22, H Radkins37, P Raffai98, S Raja48, C Rajan48, M Rakhmanov87, P Rapagnani28,81, V Raymond29, M Razzano20,21, V Re26, J Read23, T Regimbau54, L Rei47, S Reid50, D H Reitze1,6, H Rew129, S D Reyes35, E Rhoades103, F Ricci28,81, K Riles106, M Rizzo107, N A Robertson1,36, R Robie36, F Robinet24, A Rocchi15, L Rolland8, J G Rollins1, V J Roma59, J D Romano87, R Romano4,5, J H Romie7, D Rosińska43,134, S Rowan36, A Rüdiger10, P Ruggi34, K Ryan37, S Sachdev1, T Sadecki37, L Sadeghian18, M Sakellariadou135, L Salconi34, M Saleem101, F Salemi10, A Samajdar136, L Sammut120, L M Sampson85, E J Sanchez1, V Sandberg37, J R Sanders35, B Sassolas65, B S Sathyaprakash74,94, P R Saulson35, O Sauter106, R L Savage37, A Sawadsky19, P Schale59, J Scheuer85, E Schmidt103, J Schmidt10, P Schmidt1,51, R Schnabel27, R M S Schofield59, A Schönbeck27, E Schreiber10, D Schuette10,19, B F Schutz29,94, S G Schwalbe103, J Scott36, S M Scott22, D Sellers7, A S Sengupta137, D Sentenac34, V Sequino15,26, A Sergeev113, Y Setyawati11,53, D A Shaddock22, T J Shaffer37, M S Shahriar85, B Shapiro40, P Shawhan64, A Sheperd18, D H Shoemaker12, D M Shoemaker44, K Siellez44, X Siemens18, M Sieniawska43, D Sigg37, A D Silva13, A Singer1, L P Singer68, A Singh10,19,29, R Singh2, A Singhal14, A M Sintes86, B J J Slagmolen22, B Smith7, J R Smith23, R J E Smith1, E J Son116, B Sorazu36, F Sorrentino47, T Souradeep16, A P Spencer36, A K Srivastava89, A Staley39, M Steinke10, J Steinlechner36, S Steinlechner27,36, D Steinmeyer10,19, B C Stephens18, S P Stevenson45, R Stone87, K A Strain36, N Straniero65, G Stratta57,58, S E Strigin49, R Sturani130, A L Stuver7, T Z Summerscales138, L Sun128, S Sunil89, P J Sutton94, B L Swinkels34, M J Szczepańczyk103, M Tacca30, D Talukder59, D B Tanner6, M Tápai102, A Taracchini29, R Taylor1, T Theeg10, E G Thomas45, M Thomas7, P Thomas37, K A Thorne7, E Thrane120, T Tippens44, S Tiwari14,93, V Tiwari94, K V Tokmakov110, K Toland36, C Tomlinson90, M Tonelli20,21, Z Tornasi36, C I Torrie1, D Töyrä45, F Travasso32,33, G Traylor7, D Trifirò73, J Trinastic6, M C Tringali92,93, L Trozzo21,139, M Tse12, R Tso1, M Turconi54, D Tuyenbayev87, D Ugolini140, C S Unnikrishnan104, A L Urban1, S A Usman94, H Vahlbruch19, G Vajente1, G Valdes87, N van Bakel11, M van Beuzekom11, J F J van den Brand11,63, C Van Den Broeck11, D C Vander-Hyde35, L van der Schaaf11, J V van Heijningen11, A A van Veggel36, M Vardaro41,42, V Varma51, S Vass1, M Vasúth38, A Vecchio45, G Vedovato42, J Veitch45, P J Veitch70, K Venkateswara141, G Venugopalan1, D Verkindt8, F Vetrano57,58, A Viceré57,58, A D Viets18, S Vinciguerra45, D J Vine50, J-Y Vinet54, S Vitale12, T Vo35, H Vocca32,33, C Vorvick37, D V Voss6, W D Vousden45, S P Vyatchanin49, A R Wade1, L E Wade78, M Wade78, M Walker2, L Wallace1, S Walsh10,29, G Wang14,58, H Wang45, M Wang45, Y Wang52, R L Ward22, J Warner37, M Was8, J Watchi82, B Weaver37, L-W Wei54, M Weinert10, A J Weinstein1, R Weiss12, L Wen52, P Weßels10, T Westphal10, K Wette10, J T Whelan107, B F Whiting6, C Whittle120, D Williams36, R D Williams1, A R Williamson94, J L Willis142, B Willke10,19, M H Wimmer10,19, W Winkler10, C C Wipf1, H Wittel10,19, G Woan36, J Woehler10, J Worden37, J L Wright36, D S Wu10, G Wu7, W Yam12, H Yamamoto1, C C Yancey64, M J Yap22, Hang Yu12, Haocun Yu12, M Yvert8, A Zadrożny118, L Zangrando42, M Zanolin103, J-P Zendri42, M Zevin85, L Zhang1, M Zhang129, T Zhang36, Y Zhang107, C Zhao52, M Zhou85, Z Zhou85, S J Zhu10,29, X J Zhu52, M E Zucker1,12, J Zweizig1 (LIGO Scientific Collaboration, Virgo Collaboration), M Boyle143, T Chu97, D Hemberger51, I Hinder29, L E Kidder143, S Ossokine29, M Scheel51, B Szilagyi51, S Teukolsky143 and A Vano Vinuales94 Hide full author list Published 12 April 2017 • © 2017 IOP Publishing Ltd Classical and Quantum Gravity, Volume 34, Number 10 Focus Issue: Gravitational Waves Article PDF Figures References Citations PDF 258 Total downloads Cited by 1 articles Article has an altmetric score of 3 Turn on MathJax Get permission to re-use this article Share this article Article information Abstract Parameter estimates of GW150914 were obtained using Bayesian inference, based on three semi-analytic waveform models for binary black hole coalescences. These waveform models differ from each other in their treatment of black hole spins, and all three models make some simplifying assumptions, notably to neglect sub-dominant waveform harmonic modes and orbital eccentricity. Furthermore, while the models are calibrated to agree with waveforms obtained by full numerical solutions of Einstein's equations, any such calibration is accurate only to some non-zero tolerance and is limited by the accuracy of the underlying phenomenology, availability, quality, and parameter-space coverage of numerical simulations. This paper complements the original analyses of GW150914 with an investigation of the effects of possible systematic errors in the waveform models on estimates of its source parameters. To test for systematic errors we repeat the original Bayesian analysis on mock signals from numerical simulations of a series of binary configurations with parameters similar to those found for GW150914. Overall, we find no evidence for a systematic bias relative to the statistical error of the original parameter recovery of GW150914 due to modeling approximations or modeling inaccuracies. However, parameter biases are found to occur for some configurations disfavored by the data of GW150914: for binaries inclined edge-on to the detector over a small range of choices of polarization angles, and also for eccentricities greater than ~0.05. For signals with higher signal-to-noise ratio than GW150914, or in other regions of the binary parameter space (lower masses, larger mass ratios, or higher spins), we expect that systematic errors in current waveform models may impact gravitational-wave measurements, making more accurate models desirable for future observations

Directly comparing GW150914 with numerical solutions of Einstein's equations for binary black hole coalescence

We compare GW150914 directly to simulations of coalescing binary black holes in full general relativity, including several performed specifically to reproduce this event. Our calculations go beyond existing semianalytic models, because for all simulations – including sources with two independent, precessing spins – we perform comparisons which account for all the spin-weighted quadrupolar modes, and separately which account for all the quadrupolar and octopolar modes. Consistent with the posterior distributions reported in LVC-PE[1] (at the 90% credible level), we find the data are compatible with a wide range of nonprecessing and precessing simulations. Followup simulations performed using previously-estimated binary parameters most resemble the data, even when all quadrupolar and octopolar modes are included. Comparisons including only the quadrupolar modes constrain the total redshifted mass Mz ∈ [64M� − 82M�], mass ratio 1/q = m2/m1 ∈ [0.6, 1], and effective aligned spin χeff ∈ [−0.3, 0.2], where χeff = (S1/m1 + S2/m2) · Lˆ /M. Including both quadrupolar and octopolar modes, we find the mass ratio is even more tightly constrained. Even accounting for precession, simulations with extreme mass ratios and effective spins are highly inconsistent with the data, at any mass. Several nonprecessing and precessing simulations with similar mass ratio and χeff are consistent with the data. Though correlated, the components’ spins (both in magnitude and directions) are not significantly constrained by the data: the data is consistent with simulations with component spin magnitudes a1,2 up to at least 0.8, with random orientations. Further detailed followup calculations are needed to determine if the data contain a weak imprint from transverse (precessing) spins. For nonprecessing binaries, interpolating between simulations, we reconstruct a posterior distribution consistent with previous results. The final black hole’s redshifted mass is consistent with Mf,z in the range 64.0M� − 73.5M� and the final black hole’s dimensionless spin parameter is consistent with af = 0.62 − 0.73. As our approach invokes no intermediate approximations to general relativity and can strongly reject binaries whose radiation is inconsistent with the data, our analysis provides a valuable complement to LVC-PE[1]

Insights into the High-energy γ-ray Emission of Markarian 501 from Extensive Multifrequency Observations in the Fermi Era

We report on the γ-ray activity of the blazar Mrk501 during the first 480 days of Fermi operation. We find that the average Large Area Telescope (LAT) -ray spectrum of Mrk501 can be well described by a single power-law function with a photon index of 1.78 0.03. While we observe relatively mild flux variations with the Fermi-LAT (within less than a factor of two), we detect remarkable spectral variability where the hardest observed spectral index within the LAT energy range is 1.52 0.14, and the softest one is 2.51 0.20. These unexpected spectral changes do not correlate with the measured flux variations above 0.3GeV. In this paper, we also present the first results from the 4.5 month long multifrequency campaign (2009 March 15August 1) on Mrk501, which included the Very Long Baseline Array (VLBA), Swift, RXTE, MAGIC, and VERITAS, the F-GAMMA, GASP-WEBT, and other collaborations and instruments which provided excellent temporal and energy coverage of the source throughout the entire campaign. The extensive radio to TeV data set from this campaign provides us with the most detailed spectral energy distribution yet collected for this source during its relatively low activity. The average spectral energy distribution of Mrk501 is well described by the standard one-zone synchrotron self-Compton (SSC) model. In the framework of this model, we find that the dominant emission region is characterized by a size r0.1pc (comparable within a factor of few to the size of the partially resolved VLBA core at 15-43 GHz), and that the total jet power (C1044ergs1) constitutes only a small fraction (<103) of the Eddington luminosity. The energy distribution of the freshly accelerated radiating electrons required to fit the time-averaged data has a broken power-law form in the energy range 0.3 GeV-10 TeV, with spectral indices 2.2 and 2.7 below and above the break energy of 20GeV. We argue that such a form is consistent with a scenario in which the bulk of the energy dissipation within the dominant emission zone of Mrk501 is due to relativistic, proton-mediated shocks. We find that the ultrarelativistic electrons and mildly relativistic protons within the blazar zone, if comparable in number, are in approximate energy equipartition, with their energy dominating the jet magnetic field energy by about two orders of magnitude

SEARCH FOR GRAVITATIONAL WAVE BURSTS FROM SIX MAGNETARS

Soft gamma repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are thought to be magnetars: neutron stars powered by extreme magnetic fields. These rare objects are characterized by repeated and sometimes spectacular gamma-ray bursts. The burst mechanism might involve crustal fractures and excitation of non-radial modes which would emit gravitational waves (GWs). We present the results of a search for GW bursts from six galactic magnetars that is sensitive to neutron star f-modes, thought to be the most efficient GW emitting oscillatory modes in compact stars. One of them, SGR 0501+4516, is likely ~1 kpc from Earth, an order of magnitude closer than magnetars targeted in previous GW searches. A second, AXP 1E 1547.0–5408, gave a burst with an estimated isotropic energy >1044 erg which is comparable to the giant flares. We find no evidence of GWs associated with a sample of 1279 electromagnetic triggers from six magnetars occurring between 2006 November and 2009 June, in GW data from the LIGO, Virgo, and GEO600 detectors. Our lowest model-dependent GW emission energy upper limits for band- and time-limited white noise bursts in the detector sensitive band, and for f-mode ringdowns (at 1090 Hz), are 3.0 × 1044 d 2 1 erg and 1.4 × 1047 d 2 1 erg, respectively, where d[subscript 1] = dd0501 [over] 1kpc and d 0501 is the distance to SGR 0501+4516. These limits on GW emission from f-modes are an order of magnitude lower than any previous, and approach the range of electromagnetic energies seen in SGR giant flares for the first time.United States. National Aeronautics and Space AdministrationCarnegie TrustLeverhulme TrustDavid & Lucile Packard FoundationResearch Corporation for Science AdvancementAlfred P. Sloan Foundatio

Open questions in astrophysically triggered gravitational wave searches

Sources of gravitational waves are often expected to also be observable through several other messengers, such as gamma rays, X-rays, optical, radio, and/or neutrino emission. Some of these channels are already being used in searches for gravitational waves with the LIGO-GEO600-Virgo interferometer network, and others are currently being incorporated into new searches. Astrophysical targets include gamma-ray bursts, soft-gamma repeaters, supernovae, and glitching pulsars. The simultaneous observation of electromagnetic or neutrino emission could be a crucial aspect for the first direct detection of gravitational waves. Information on the progenitor, such as trigger time, direction and expected frequency range, can enhance our ability to identify gravitational wave signatures with amplitudes close to the noise floor of the detector. Furthermore, combining gravitational waves with electromagnetic and neutrino observations will enable the extraction of scientific insight that was hidden from us before. The paper discusses the status of transient multimessenger detection efforts as well as intriguing questions that might be resolved in the future by advanced and third generation gravitational wave detector

Joint searches for gravitational waves and high-energy neutrinos

Many of the astrophysical sources and violent phenomena observed in our Universe are potential joint emitters of gravitational waves and high-energy cosmic radiation, in the form of photons, hadrons, and also neutrinos. This has triggered a collaborative analysis project between gravitational wave detectors and high-energy neutrino telescopes. In this article, we review some of the motivations for having pursuing science jointly and present the effort’s status