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Search for gravitational waves from Scorpius X-1 with a hidden Markov model in O3 LIGO data

Physical Review D 2022年第6期106卷 062002-062002页

作者： R. Abbott H. Abe F. Acernese K. Ackley N. Adhikari R. X. Adhikari V. K. Adkins V. B. Adya C. Affeldt D. Agarwal M. Agathos K. Agatsuma N. Aggarwal O. D. Aguiar L. Aiello A. Ain P. Ajith T. Akutsu S. Albanesi R. A. Alfaidi A. Allocca P. A. Altin A. Amato C. Anand S. Anand A. Ananyeva S. B. Anderson W. G. Anderson M. Ando T. Andrade N. Andres M. Andrés-Carcasona T. Andrić S. V. Angelova S. Ansoldi J. M. Antelis S. Antier T. Apostolatos E. Z. Appavuravther S. Appert S. K. Apple K. Arai A. Araya M. C. Araya J. S. Areeda M. Arène N. Aritomi N. Arnaud M. Arogeti S. M. Aronson H. Asada Y. Asali G. Ashton Y. Aso M. Assiduo S. Assis de Souza Melo S. M. Aston P. Astone F. Aubin K. AultONeal C. Austin S. Babak F. Badaracco M. K. M. Bader C. Badger S. Bae Y. Bae A. M. Baer S. Bagnasco Y. Bai J. Baird R. Bajpai T. Baka M. Ball G. Ballardin S. W. Ballmer A. Balsamo G. Baltus S. Banagiri B. Banerjee D. Bankar J. C. Barayoga C. Barbieri B. C. Barish D. Barker P. Barneo F. Barone B. Barr L. Barsotti M. Barsuglia D. Barta J. Bartlett M. A. Barton I. Bartos S. Basak R. Bassiri A. Basti M. Bawaj J. C. Bayley M. Bazzan B. R. Becher B. Bécsy V. M. Bedakihale F. Beirnaert M. Bejger I. Belahcene V. Benedetto D. Beniwal M. G. Benjamin T. F. Bennett J. D. Bentley M. BenYaala S. Bera M. Berbel F. Bergamin B. K. Berger S. Bernuzzi D. Bersanetti A. Bertolini J. Betzwieser D. Beveridge R. Bhandare A. V. Bhandari U. Bhardwaj R. Bhatt D. Bhattacharjee S. Bhaumik A. Bianchi I. A. Bilenko G. Billingsley S. Bini R. Birney O. Birnholtz S. Biscans M. Bischi S. Biscoveanu A. Bisht B. Biswas M. Bitossi M.-A. Bizouard J. K. Blackburn C. D. Blair D. G. Blair R. M. Blair F. Bobba N. Bode M. Boër G. Bogaert M. Boldrini G. N. Bolingbroke L. D. Bonavena F. Bondu E. Bonilla R. Bonnand P. Booker B. A. Boom R. Bork V. Boschi N. Bose S. Bose V. Bossilkov V. Boudart Y. Bouffanais A. Bozzi C. Bradaschia P. R. Brady A. Bramley A. Branch M. Branchesi J. E. Brau M. Breschi T. Briant J. H. Briggs A. Brillet M. Brinkmann P. Brockill A. F. Brooks J. Brooks D. D. Brown LIGO Laboratory California Institute of Technology Pasadena California 91125 USA Graduate School of Science Tokyo Institute of Technology Meguro-ku Tokyo 152-8551 Japan Dipartimento di Farmacia Università di Salerno I-84084 Fisciano Salerno Italy INFN Sezione di Napoli Complesso Universitario di Monte S. Angelo I-80126 Napoli Italy OzGrav School of Physics and Astronomy Monash University Clayton 3800 Victoria Australia University of Wisconsin-Milwaukee Milwaukee Wisconsin 53201 USA Louisiana State University Baton Rouge Louisiana 70803 USA OzGrav Australian National University Canberra Australian Capital Territory 0200 Australia Max Planck Institute for Gravitational Physics (Albert Einstein Institute) D-30167 Hannover Germany Leibniz Universität Hannover D-30167 Hannover Germany Inter-University Centre for Astronomy and Astrophysics Pune 411007 India University of Cambridge Cambridge CB2 1TN United Kingdom Theoretisch-Physikalisches Institut Friedrich-Schiller-Universität Jena D-07743 Jena Germany University of Birmingham Birmingham B15 2TT United Kingdom Northwestern University Evanston Illinois 60208 USA Instituto Nacional de Pesquisas Espaciais 12227-010 São José dos Campos São Paulo Brazil Cardiff University Cardiff CF24 3AA United Kingdom INFN Sezione di Pisa I-56127 Pisa Italy International Centre for Theoretical Sciences Tata Institute of Fundamental Research Bengaluru 560089 India Gravitational Wave Science Project National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan Advanced Technology Center National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan Dipartimento di Fisica Università degli Studi di Torino I-10125 Torino Italy INFN Sezione di Torino I-10125 Torino Italy SUPA University of Glasgow Glasgow G12 8QQ United Kingdom Università di Napoli “Federico II ” Complesso Universitario di Monte S. Angelo I-80126 Napoli Italy Université de Lyon Université Claude Bernard Lyon 1

Results are presented for a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to allow for spin wandering. This search improves on previous HMM-based searches of Laser Interferometer Gravitational-Wave Observatory data by including the orbital period in the search template grid, and by analyzing data from the latest (third) observing run. In the frequency range searched, from 60 to 500 Hz, we find no evidence of gravitational radiation. This is the most sensitive search for Scorpius X-1 using a HMM to date. For the most sensitive subband, starting at 256.06 Hz, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=6.16×10−26, assuming the orbital inclination angle takes its electromagnetically restricted value ι=44°. The upper limits on gravitational wave strain reported here are on average a factor of ∼3 lower than in the second observing run HMM search. This is the first Scorpius X-1 HMM search with upper limits that reach below the indirect torque-balance limit for certain subbands, assuming ι=44°.

关键词： Gravitational waves Binary stars Neutron stars & pulsars

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All-sky search for gravitational wave emission from scalar boson clouds around spinning black holes in LIGO O3 data

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Physical Review D 2022年第10期105卷 102001-102001页

作者： R. Abbott H. Abe F. Acernese K. Ackley N. Adhikari R. X. Adhikari V. K. Adkins V. B. Adya C. Affeldt D. Agarwal M. Agathos K. Agatsuma N. Aggarwal O. D. Aguiar L. Aiello A. Ain P. Ajith T. Akutsu S. Albanesi R. A. Alfaidi A. Allocca P. A. Altin A. Amato C. Anand S. Anand A. Ananyeva S. B. Anderson W. G. Anderson M. Ando T. Andrade N. Andres M. Andrés-Carcasona T. Andrić S. V. Angelova S. Ansoldi J. M. Antelis S. Antier T. Apostolatos E. Z. Appavuravther S. Appert S. K. Apple K. Arai A. Araya M. C. Araya J. S. Areeda M. Arène N. Aritomi N. Arnaud M. Arogeti S. M. Aronson K. G. Arun H. Asada Y. Asali G. Ashton Y. Aso M. Assiduo S. Assis de Souza Melo S. M. Aston P. Astone F. Aubin K. AultONeal C. Austin S. Babak F. Badaracco M. K. M. Bader C. Badger S. Bae Y. Bae A. M. Baer S. Bagnasco Y. Bai J. Baird R. Bajpai T. Baka M. Ball G. Ballardin S. W. Ballmer A. Balsamo G. Baltus S. Banagiri B. Banerjee D. Bankar J. C. Barayoga C. Barbieri B. C. Barish D. Barker P. Barneo F. Barone B. Barr L. Barsotti M. Barsuglia D. Barta J. Bartlett M. A. Barton I. Bartos S. Basak R. Bassiri A. Basti M. Bawaj J. C. Bayley M. Bazzan B. R. Becher B. Bécsy V. M. Bedakihale F. Beirnaert M. Bejger I. Belahcene V. Benedetto D. Beniwal M. G. Benjamin T. F. Bennett J. D. Bentley M. BenYaala S. Bera M. Berbel F. Bergamin B. K. Berger S. Bernuzzi D. Bersanetti A. Bertolini J. Betzwieser D. Beveridge R. Bhandare A. V. Bhandari U. Bhardwaj R. Bhatt D. Bhattacharjee S. Bhaumik A. Bianchi I. A. Bilenko G. Billingsley S. Bini R. Birney O. Birnholtz S. Biscans M. Bischi S. Biscoveanu A. Bisht B. Biswas M. Bitossi M.-A. Bizouard J. K. Blackburn C. D. Blair D. G. Blair R. M. Blair F. Bobba N. Bode M. Boër G. Bogaert M. Boldrini G. N. Bolingbroke L. D. Bonavena F. Bondu E. Bonilla R. Bonnand P. Booker B. A. Boom R. Bork V. Boschi N. Bose S. Bose V. Bossilkov V. Boudart Y. Bouffanais A. Bozzi C. Bradaschia P. R. Brady A. Bramley A. Branch M. Branchesi J. E. Brau M. Breschi T. Briant J. H. Briggs A. Brillet M. Brinkmann P. Brockill A. F. Brooks J. Brooks D LIGO Laboratory California Institute of Technology Pasadena California 91125 USA Graduate School of Science Tokyo Institute of Technology Meguro-ku Tokyo 152-8551 Japan Dipartimento di Farmacia Università di Salerno I-84084 Fisciano Salerno Italy INFN Sezione di Napoli Complesso Universitario di Monte S. Angelo I-80126 Napoli Italy OzGrav School of Physics and Astronomy Monash University Clayton 3800 Victoria Australia University of Wisconsin-Milwaukee Milwaukee Wisconsin 53201 USA Louisiana State University Baton Rouge Louisiana 70803 USA OzGrav Australian National University Canberra Australian Capital Territory 0200 Australia Max Planck Institute for Gravitational Physics (Albert Einstein Institute) D-30167 Hannover Germany Leibniz Universität Hannover D-30167 Hannover Germany Inter-University Centre for Astronomy and Astrophysics Pune 411007 India University of Cambridge Cambridge CB2 1TN United Kingdom Theoretisch-Physikalisches Institut Friedrich-Schiller-Universität Jena D-07743 Jena Germany University of Birmingham Birmingham B15 2TT United Kingdom Northwestern University Evanston Illinois 60208 USA Instituto Nacional de Pesquisas Espaciais 12227-010 São José dos Campos São Paulo Brazil Cardiff University Cardiff CF24 3AA United Kingdom INFN Sezione di Pisa I-56127 Pisa Italy International Centre for Theoretical Sciences Tata Institute of Fundamental Research Bengaluru 560089 India Gravitational Wave Science Project National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan Advanced Technology Center National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan Dipartimento di Fisica Università degli Studi di Torino I-10125 Torino Italy INFN Sezione di Torino I-10125 Torino Italy SUPA University of Glasgow Glasgow G12 8QQ United Kingdom Università di Napoli “Federico II” Complesso Universitario di Monte S. Angelo I-80126 Napoli Italy Université de Lyon Université Claude Bernard Lyon 1

This paper describes the first all-sky search for long-duration, quasimonochromatic gravitational-wave signals emitted by ultralight scalar boson clouds around spinning black holes using data from the third observing run of Advanced LIGO. We analyze the frequency range from 20 to 610 Hz, over a small frequency derivative range around zero, and use multiple frequency resolutions to be robust towards possible signal frequency wanderings. Outliers from this search are followed up using two different methods, one more suitable for nearly monochromatic signals, and the other more robust towards frequency fluctuations. We do not find any evidence for such signals and set upper limits on the signal strain amplitude, the most stringent being ≈10−25 at around 130 Hz. We interpret these upper limits as both an “exclusion region” in the boson mass/black hole mass plane and the maximum detectable distance for a given boson mass, based on an assumption of the age of the black hole/boson cloud system.

关键词： Classical black holes Gravitational wave detection Gravitational wave sources Particle astrophysics Particle dark matter

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Device-Free Human Presence Detection Using Frequency Domain

Device-Free Human Presence Detection Using Frequency Domain

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IEEE International Workshop on Consumer Electronics

作者： Bojan Mrazovac Branislav M. Todorovic Dragan Kukolj Miodrag Temerinac Department for Computing and Control Engineering Faculty of Technical Sciences Novi Sad Serbia RT-RK Institute for Computer Based Systems Narodnog fronta 23a Novi Sad Serbia

ISBN: (纸本)9781509042692

Device-free human presence (DFHP) detection is a novel technique, mainly applicable to wireless sensor networks in which a human does not need to carry a wireless transceiver to be detected. Irregularities in the radio signal propagation pattern, expressed in a form of received signal strength indicator's (RSSI) variations can indicate possible presence of a human within the existing radio network. In this paper we propose DFHP detection method based on frequency analysis of RSSI variations. The main advantage of the proposed method compared to human detection method based on information entropy is the possibility to determine human presence from furniture layout change. The main drawback is a disability to recognize the absence from the presence of a motionless person in an environment. However, the combination of these two approaches defines a robust and cost-effective DFHP detection method that can be used in various smart home systems without the need for specific hardware installation and exploitation procedures.

关键词： fast Fourier transform human presence detection information entropy rssi

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Accuracy of the frequency and phase measurement concerning different noise sources for phase Doppler Anemometry 3

Accuracy of the frequency and phase measurement concerning d...

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3rd IEEE International Conference on Smart Instrumentation, Measurement and Applications, ICSIMA 2015

作者： Zhang, Lu Kulon, Janusz Yan, Yong School of Control and Computer Engineering North China Electric Power University Beijing102206 China Faculty of Computing Engineering and Science University of South Wales PontypriddCF37 1DL United Kingdom School of Engineering and Digital Arts University of Kent Canterbury KentCT2 7NT United Kingdom

ISBN: (纸本)9781467372558

The measurement accuracy of the estimation of the Doppler frequency and the signal phase difference in Phase Doppler Anemometry (PDA) systems is investigated in this paper by taking into account the effect of the particle trajectory via the measurement volume and the different noise sources. Both the signal dependent (quantum shot) noise and the signal independent (thermal and dark current) noise are considered. The minimum achievable measurement uncertainty of the phase shift estimation for the signal independent noise is determined by employing the 2D model of the Doppler Burst Signal with the Gaussian envelope and compared with the performance of the correlation method. Additionally, the Cramér-Rao lower bound (CRLB) of the frequency estimation concerning the quantum shot noise is calculated. The numerical examples show the performance of the correlation method with various parameter configurations compared with the derived CRLB. The numerical results confirm the validity of the analysis in terms of the relative effect of the particle trajectory, relative measurement time, size of the volume and signal-to-noise ratio on the accuracy of the estimation. © 2015 IEEE.

关键词： Uncertainty analysis

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Cooperative avoidance control-based interval fuzzy kohonen networks algorithm in simple swarm robots

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Telkomnika (Telecommunication computing Electronics and control) 2014年第4期12卷 795-810页

作者： Nurmaini, Siti Zaiton, Siti Firnando, Ricy Robotic and Control Research Lab Faculty of Computer Science University of Sriwijaya Jl Raya Palembang-Prabumulih Km 32 Inderalaya-OganIlir Indonesia Soft Computing Research Group Faculty of Computing Universiti Teknologi Malaysia Skudai Johor Bahru Malaysia

A novel techniqueto control swarm robot's movement is presented and analyzed in this paper. It allows a group of robots to move as a unique entity performing the following function such as obstacle avoidance at group *** control strategyenhances the mobile robot's performance whereby their forthcoming decisions are impacted by its previous experiences during the navigation apart from the current range inputs. Interval Fuzzy-Kohonen Network (IFKN) algorithm is utilized in this strategy. By employing a small number of rules, the IFKN algorithms can be adapted toswarms reactive control. The control strategy provides much faster response compare to Fuzzy Kohonen Network (FKN) algorithm to expected events. The effectiveness of the proposed technique is also demonstrated in a series of practical test on our experimental by using five low costrobots with limited sensor abilities and low computational effort on each single robot in the *** results show that swarm robots based on proposed technique have the ability to perform cooperativebehavior, produces minimum collision and capable to navigate around squareshapes obstacles.

关键词： Robots

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Erratum to: Multi-camera systems use for dental arch shape measurement

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The Visual Computer 2016年第5期33卷 689-689页

作者： Aleš Procházka Magdaléna Kašparová Mohammadreza Yadollahi Oldřich Vyšata Lucie Grajciarová Department of Computing and Control Engineering Institute of Chemical Technology Prague 6 Czech Republic Department of Stomatology 2nd Medical Faculty Charles University Prague 5 Czech Republic Department of Neurology Faculty of Medicine in Hradec Králové Charles University Hradec Kralove Czech Republic

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Stabilizing Transmission Intervals for Networked control Systems with Nonlinear Delay Dynamics

Stabilizing Transmission Intervals for Networked Control Sys...

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IEEE Annual Conference on Decision and control

作者： Domagoj Tolic Sandra Hirche Faculty of Electrical Engineering and Computing University of Zagreb Unska 3 10000 Zagreb Croatia Chair of Information-oriented Control Technische Universitat Munchen Arcisstrasse 21 D-80290 Munchen Germany

ISBN: (纸本)9781479978878

In this paper, we consider a nonlinear delay process to be controlled over a communication network in the presence of disturbances and study robustness of the resulting closed-loop system with respect to network-induced phenomena such as sampled, distorted and delayed data as well as scheduling protocols. In particular, we compute the Maximally Allowable Transfer Interval (MATI) for which a prescribed L_p-gain, as a measure of control performance, is attained. The proposed methodology combines impulsive delay system modeling with Lyapunov-Razumikhin techniques to allow for communication delays greater than MATIs. Other salient features of our methodology are the consideration of nonuniform variable delays and employment of model-based estimators to prolong MATIs. The present stability results are provided for the class of Uniformly Globally Exponentially Stable (UGES) scheduling protocols such as Round Robin (RR) and Try-Once-Discard (TOD). Finally, a nonlinear example is provided to demonstrate the benefits of our methodology.

关键词： Networked control systems networks(communications) control systems control performance Induction loop systems nonlinearity delay Delay systems

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Robust Event-based Data Scheduling for Resource Constrained Networked control Systems

Robust Event-based Data Scheduling for Resource Constrained ...

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American control Conference

作者： Mohammad H. Mamduhi Domagoj Tolic Sandra Hirche Institute for Information-oriented Control Technische Universitat Munchen Arcisstrasse 21 D-80290 Munchen Germany University of Zagreb Faculty of Electrical Engineering and Computing Unska 3 10000 Zagreb Croatia

ISBN: (纸本)9781479917730

This paper modifies a recently proposed event-based probabilistic medium access for multi-loop Networked control Systems (NCSs) over a shared communication channel subject to limited capacity and uncertainties and study its robustness. The novel design combines deterministic and probabilistic attributes to efficiently allocate the channel access among the control loops in the presence of network-induced phenomena such as packet dropouts and scheduling with delayed information update. Since the scheduler receives error information from a number of systems simultaneously, this sheer amount of information cannot always be processed in timely manner, which in turn gives rise to delays. Given the local error thresholds, the subsystems with error values lower than their corresponding thresholds are deterministically excluded from the medium access competition in favor of those with larger errors. In case of resource scarcity, the scheduler probabilistically allocates the channel to those that exceed the local thresholds according to an error-dependent priority measure. We show stochastic stability of such NCSs in terms of f-ergodicity of the network-induced error, which is modeled as a Markov chain. Numerical results validate our stability results in the presence of packet dropouts and delayed data update.

关键词： Event-based Networked control systems scheduler program resource scarcity Media Access

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Analysis of Microgrid Power Flow Optimization with Consideration of Residual Storages State

Analysis of Microgrid Power Flow Optimization with Considera...

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European control Conference

作者： Marko Gulin Mario Vasak Mato Baotic Department of Control and Computer Engineering of University of Zagreb Faculty of Electrical Engineering and Computing

ISBN: (纸本)9781467371605

Microgrid is a cluster of distributed generation sources, storages and loads that cooperate so as to improve the reliability and quality of the local power supply and of the power system. In this paper we present a power flow optimization of a DC microgrid that consists of photovoltaic array, batteries stack and fuel cells stack with electrolyser, and is connected to the grid via bidirectional power converter. The optimization problem aims to minimize microgrid operating costs and is formulated using a linear program that takes into account the storages charge and discharge efficiency, and considers the residual state of the energy storage systems in the criterion function. Performance of the proposed approach is verified through year-scale simulations based on the actual meteorological, electricity price and consumption data. The analysis performed points out that especially for short prediction horizons it is very important to ensure proper penalization of the residual storages state in the criterion function in order to yield optimum revenue from microgrid operation.

关键词： MICRO-GRID storages criterion function power systems Power flow electrolyzer Cache Memory System linear programming Analysis Electric Power Source

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Search for anisotropic gravitational-wave backgrounds using data from Advanced LIGO and Advanced Virgo’s first three observing runs

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Physical Review D 2021年第2期104卷 022005-022005页

作者： R. Abbott T. D. Abbott S. Abraham F. Acernese K. Ackley A. Adams C. Adams R. X. Adhikari V. B. Adya C. Affeldt D. Agarwal M. Agathos K. Agatsuma N. Aggarwal O. D. Aguiar L. Aiello A. Ain P. Ajith T. Akutsu K. M. Aleman G. Allen A. Allocca P. A. Altin A. Amato S. Anand A. Ananyeva S. B. Anderson W. G. Anderson M. Ando S. V. Angelova S. Ansoldi J. M. Antelis S. Antier S. Appert Koya Arai Koji Arai Y. Arai S. Araki A. Araya M. C. Araya J. S. Areeda M. Arène N. Aritomi N. Arnaud S. M. Aronson H. Asada Y. Asali G. Ashton Y. Aso S. M. Aston P. Astone F. Aubin P. Aufmuth K. AultONeal C. Austin S. Babak F. Badaracco M. K. M. Bader S. Bae Y. Bae A. M. Baer S. Bagnasco Y. Bai L. Baiotti J. Baird R. Bajpai M. Ball G. Ballardin S. W. Ballmer M. Bals A. Balsamo G. Baltus S. Banagiri D. Bankar R. S. Bankar J. C. Barayoga C. Barbieri B. C. Barish D. Barker P. Barneo F. Barone B. Barr L. Barsotti M. Barsuglia D. Barta J. Bartlett M. A. Barton I. Bartos R. Bassiri A. Basti M. Bawaj J. C. Bayley A. C. Baylor M. Bazzan B. Bécsy V. M. Bedakihale M. Bejger I. Belahcene V. Benedetto D. Beniwal M. G. Benjamin T. F. Bennett J. D. Bentley M. BenYaala F. Bergamin B. K. Berger S. Bernuzzi D. Bersanetti A. Bertolini J. Betzwieser R. Bhandare A. V. Bhandari D. Bhattacharjee S. Bhaumik J. Bidler I. A. Bilenko G. Billingsley R. Birney O. Birnholtz S. Biscans M. Bischi S. Biscoveanu A. Bisht B. Biswas M. Bitossi M.-A. Bizouard J. K. Blackburn J. Blackman C. D. Blair D. G. Blair R. M. Blair F. Bobba N. Bode M. Boer G. Bogaert M. Boldrini F. Bondu E. Bonilla R. Bonnand P. Booker B. A. Boom R. Bork V. Boschi N. Bose S. Bose V. Bossilkov V. Boudart Y. Bouffanais A. Bozzi C. Bradaschia P. R. Brady A. Bramley A. Branch M. Branchesi J. E. Brau M. Breschi T. Briant J. H. Briggs A. Brillet M. Brinkmann P. Brockill A. F. Brooks J. Brooks D. D. Brown S. Brunett G. Bruno R. Bruntz J. Bryant A. Buikema T. Bulik H. J. Bulten A. Buonanno R. Buscicchio D. Buskulic R. L. Byer L. Cadonati M. Caesar G. Cagnoli C. Cahillane H. W. Cain, III J. Calderón Bustillo J. LIGO Laboratory California Institute of Technology Pasadena California 91125 USA Louisiana State University Baton Rouge Louisiana 70803 USA Inter-University Centre for Astronomy and Astrophysics Pune 411007 India Dipartimento di Farmacia Università di Salerno I-84084 Fisciano Salerno Italy INFN Sezione di Napoli Complesso Universitario di Monte S.Angelo I-80126 Napoli Italy OzGrav School of Physics & Astronomy Monash University Clayton 3800 Victoria Australia Christopher Newport University Newport News Virginia 23606 USA LIGO Livingston Observatory Livingston Louisiana 70754 USA OzGrav Australian National University Canberra Australian Capital Territory 0200 Australia Max Planck Institute for Gravitational Physics (Albert Einstein Institute) D-30167 Hannover Germany Leibniz Universität Hannover D-30167 Hannover Germany University of Cambridge Cambridge CB2 1TN United Kingdom Theoretisch-Physikalisches Institut Friedrich-Schiller-Universität Jena D-07743 Jena Germany University of Birmingham Birmingham B15 2TT United Kingdom Center for Interdisciplinary Exploration & Research in Astrophysics (CIERA) Northwestern University Evanston Illinois 60208 USA Instituto Nacional de Pesquisas Espaciais 12227-010 São José dos Campos São Paulo Brazil Gravity Exploration Institute Cardiff University Cardiff CF24 3AA United Kingdom Gran Sasso Science Institute (GSSI) I-67100 L’Aquila Italy INFN Laboratori Nazionali del Gran Sasso I-67100 Assergi Italy INFN Sezione di Pisa I-56127 Pisa Italy Università di Pisa I-56127 Pisa Italy International Centre for Theoretical Sciences Tata Institute of Fundamental Research Bengaluru 560089 India Gravitational Wave Science Project National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan Advanced Technology Center National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan California State University Fullerton Fullerton California 92831 USA NCSA University of Illinois

We report results from searches for anisotropic stochastic gravitational-wave backgrounds using data from the first three observing runs of the Advanced LIGO and Advanced Virgo detectors. For the first time, we include Virgo data in our analysis and run our search with a new efficient pipeline called pystoch on data folded over one sidereal day. We use gravitational-wave radiometry (broadband and narrow band) to produce sky maps of stochastic gravitational-wave backgrounds and to search for gravitational waves from point sources. A spherical harmonic decomposition method is employed to look for gravitational-wave emission from spatially-extended sources. Neither technique found evidence of gravitational-wave signals. Hence we derive 95% confidence-level upper limit sky maps on the gravitational-wave energy flux from broadband point sources, ranging from Fα,Θ<(0.013–7.6)×10−8 erg cm−2 s−1 Hz−1, and on the (normalized) gravitational-wave energy density spectrum from extended sources, ranging from Ωα,Θ<(0.57–9.3)×10−9 sr−1, depending on direction (Θ) and spectral index (α). These limits improve upon previous limits by factors of 2.9–3.5. We also set 95% confidence level upper limits on the frequency-dependent strain amplitudes of quasimonochromatic gravitational waves coming from three interesting targets, Scorpius X-1, SN 1987A and the Galactic Center, with best upper limits range from h0<(1.7–2.1)×10−25, a factor of ≥2.0 improvement compared to previous stochastic radiometer searches.

关键词： Experimental studies of gravity General relativity Gravitational waves

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