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The International Pulsar Timing Array second data release: Search for an isotropic gravitational wave background

Antoniadis, J. and Arzoumanian, Z. and Babak, S. and Bailes, M. and Bak Nielsen, A.-S. and Baker, P. T. and Bassa, C. G. and Bécsy, B. and Berthereau, A. and Bonetti, M. and Brazier, A. and Brook, P. R. and Burgay, M. and Burke-Spolaor, S. and Caballero, R. N. and Casey-Clyde, J. A. and Chalumeau, A. and Champion, D. J. and Charisi, M. and Chatterjee, S. and Chen, S. and Cognard, I. and Cordes, J. M. and Cornish, N. J. and Crawford, F. and Cromartie, H. T. and Crowter, K. and Dai, S. and DeCesar, M. E. and Demorest, P. B. and Desvignes, G. and Dolch, T. and Drachler, B. and Falxa, M. and Ferrara, E. C. and Fiore, W. and Fonseca, E. and Gair, J. R. and Garver-Daniels, N. and Goncharov, B. and Good, D. C. and Graikou, E. and Guillemot, L. and Guo, Y. J. and Hazboun, J. S. and Hobbs, G. and Hu, H. and Islo, K. and Janssen, G. H. and Jennings, R. J. and Johnson, A. D. and Jones, M. L. and Kaiser, A. R. and Kaplan, D. L. and Karuppusamy, R. and Keith, M. J. and Kelley, L. Z. and Kerr, M. and Key, J. S. and Kramer, M. and Lam, M. T. and Lamb, W. G. and Lazio, T. J. W. and Lee, K. J. and Lentati, L. and Liu, K. and Luo, J. and Lynch, R. S. and Lyne, A. G. and Madison, D. R. and Main, R. A. and Manchester, R. N. and McEwen, A. and McKee, J. W. and McLaughlin, M. A. and Mickaliger, M. B. and Mingarelli, C. M. F. and Ng, C. and Nice, D. J. and Osłowski, S. and Parthasarathy, A. and Pennucci, T. T. and Perera, B. B. P. and Perrodin, D. and Petiteau, A. and Pol, N. S. and Porayko, N. K. and Possenti, A. and Ransom, S. M. and Ray, P. S. and Reardon, D. J. and Russell, C. J. and Samajdar, A. and Sampson, L. M. and Sanidas, S. and Sarkissian, J. M. and Schmitz, K. and Schult, L. and Sesana, A. and Shaifullah, G. and Shannon, R. M. and Shapiro-Albert, B. J. and Siemens, X. and Simon, J. and Smith, T. L. and Speri, L. and Spiewak, R. and Stairs, I. H. and Stappers, B. W. and Stinebring, D. R. and Swiggum, J. K. and Taylor, S. R. and Theureau, G. and Tiburzi, C. and Vallisneri, M. and van der Wateren, E. and Vecchio, A. and Verbiest, J. P. W. and Vigeland, S. J. and Wahl, H. and Wang, J. B. and Wang, J. and Wang, L. and Witt, C. A. and Zhang, S. and Zhu, X. J. (2022) The International Pulsar Timing Array second data release: Search for an isotropic gravitational wave background. Monthly Notices of the Royal Astronomical Society, 510 (4). pp. 4873-4887. ISSN 0035-8711. doi:10.1093/mnras/stab3418. https://resolver.caltech.edu/CaltechAUTHORS:20220329-726529570

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Abstract

We searched for an isotropic stochastic gravitational wave background in the second data release of the International Pulsar Timing Array, a global collaboration synthesizing decadal-length pulsar-timing campaigns in North America, Europe, and Australia. In our reference search for a power law strain spectrum of the form h_c = A(f/1yr⁻¹)^α, we found strong evidence for a spectrally-similar low-frequency stochastic process of amplitude A =3.8^(+6.3)_(−2.5) × 10⁻¹⁵ and spectral index α =− 0.5 ± 0.5, where the uncertainties represent 95% credible regions, using information from the auto- and cross-correlation terms between the pulsars in the array. For a spectral index of α = −2/3, as expected from a population of inspiralling supermassive black hole binaries, the recovered amplitude is A = 2.8^(+1.2)_(−0.8) × 1010⁻¹⁵. Nonetheless, no significant evidence of the Hellings-Downs correlations that would indicate a gravitational-wave origin was found. We also analyzed the constituent data from the individual pulsar timing arrays in a consistent way, and clearly demonstrate that the combined international data set is more sensitive. Furthermore, we demonstrate that this combined data set produces comparable constraints to recent single-array data sets which have more data than the constituent parts of the combination. Future international data releases will deliver increased sensitivity to gravitational wave radiation, and significantly increase the detection probability.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1093/mnras/stab3418DOIArticle
https://arxiv.org/abs/2201.03980arXivDiscussion Paper
https://gitlab.com/IPTA/DR2Related ItemTiming data
https://ipta4gw.orgRelated ItemSelected chain files
https://doi.org/10.5281/zenodo.5787557DOISelected chain files
ORCID:
AuthorORCID
Antoniadis, J.0000-0003-4453-3776
Bak Nielsen, A.-S.0000-0002-1298-9392
Bonetti, M.0000-0001-7889-6810
Brook, P. R.0000-0003-3053-6538
Burgay, M.0000-0002-8265-4344
Caballero, R. N.0000-0001-9084-9427
Chalumeau, A.0000-0003-2111-1001
Champion, D. J.0000-0003-1361-7723
Chen, S.0000-0002-3118-5963
Crawford, F.0000-0002-2578-0360
Crowter, K.0000-0002-1529-5169
Dai, S.0000-0002-9618-2499
Desvignes, G.0000-0003-3922-4055
Goncharov, B.0000-0003-3189-5807
Hazboun, J. S.0000-0003-2742-3321
Hobbs, G.0000-0003-1502-100X
Hu, H.0000-0002-3407-8071
Kaplan, D. L.0000-0001-6295-2881
Kelley, L. Z.0000-0002-6625-6450
Kerr, M.0000-0002-0893-4073
Kramer, M.0000-0002-4175-2271
Lazio, T. J. W.0000-0002-3873-5497
McKee, J. W.0000-0002-2885-8485
McLaughlin, M. A.0000-0001-7697-7422
Mingarelli, C. M. F.0000-0002-4307-1322
Ng, C.0000-0002-3616-5160
Parthasarathy, A.0000-0002-4140-5616
Perera, B. B. P.0000-0002-8509-5947
Ransom, S. M.0000-0001-5799-9714
Ray, P. S.0000-0002-5297-5278
Reardon, D. J.0000-0002-2035-4688
Schult, L.0000-0001-6425-7807
Shaifullah, G.0000-0002-8452-4834
Shannon, R. M.0000-0002-7285-6348
Simon, J.0000-0003-1407-6607
Speri, L.0000-0002-5442-7267
Spiewak, R.0000-0002-6730-3298
Stappers, B. W.0000-0001-9242-7041
Vallisneri, M.0000-0002-4162-0033
Verbiest, J. P. W.0000-0002-4088-896X
Wang, L.0000-0003-0757-3584
Zhu, X. J.0000-0001-7049-6468
Additional Information:© 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model) Accepted 2021 No v ember 15. Received 2021 November 4; in original form 2021 September 23. The International Pulsar Timing Array (IPTA) is a consortium of existing Pulsar Timing Array collaborations, namely, the European Pulsar Timing Array (EPTA), North American Nanohertz Observatory for Gravitational Waves (NANOGrav), Parkes Pulsar Timing Array (PPTA), and the recent addition of the Indian Pulsar Timing Array (InPTA). Observing collaborations from China and South Africa are also part of the IPTA. The EPTA is a collaboration between European and partner institutes with the aim to provide high precision pulsar timing to work towards the direct detection of low-frequency gravitational waves. An Advanced Grant of the European Research Council to implement the Large European Array for Pulsars (LEAP) also provides funding. Part of this work is based on observations with the 100-m telescope of the Max-Planck-Institut für Radioastronomie (MPIfR) at Effelsberg in Germany. Pulsar research at the Jodrell Bank Centre for Astrophysics and the observations using the Lovell Telescope are supported by a Consolidated Grant (ST/T000414/1) from the UK’s Science and Technology Facilities Council. The Nançay radio Observatory is operated by the Paris Observatory, associated to the French Centre National de la Recherche Scientifique (CNRS), and partially supported by the Region Centre in France. We acknowledge financial support from ‘Programme National de Cosmologie and Galaxies’ (PNCG), and ‘Programme National Hautes Energies’ (PNHE) funded by CNRS/INSU-IN2P3-INP, CEA and CNES, France. We acknowledge financial support from Agence Nationale de la Recherche (ANR-18-CE31-0015), France. The Westerbork Synthesis Radio Telescope is operated by the Netherlands Institute for Radio Astronomy (ASTRON) with support from the Netherlands Foundation for Scientific Research (NWO). The Sardinia Radio Telescope (SRT) is funded by the Department of University and Research (MIUR), the Italian Space Agency (ASI), and the Autonomous Region of Sardinia (RAS) and is operated as National Facility by the National Institute for Astrophysics (INAF). The NANOGrav Physics Frontiers Center is supported by NSF award number 1430284. The Green Bank Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The Arecibo Observatory is a facility of the National Science Foundation operated under cooperative agreement by the University of Central Florida in alliance with Yang Enterprises, Inc. and Universidad Metropolitana. The Parkes radio telescope (Murriyang) is part of the Australia Telescope which is funded by the Commonwealth Government for operation as a National Facility managed by CSIRO. JA acknowleges support by the Stavros Niarchos Foundation (SNF) and the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the 2nd Call of ‘Science and Society’ Action Always strive for excellence – ‘Theodoros Papazoglou’ (Project Number: 01431). SBS acknowledges generous support by the NSF through grant AST-1815664. The work is supported by National SKA program of China 2020SKA0120100, Max-Planck Partner Group, NSFC 11690024, CAS Cultivation Project for FAST Scientific. JACC was supported in part by NASA CT Space Grant PTE Federal Award Number 80NSSC20M0129. CMFM and JACC are also supported by the National Science Foundation’s NANOGrav Physics Frontier Center, Award Number 2020265. AC acknowledges support from the Paris Île-de-France Region. Support for HTC was provided by NASA through the NASA Hubble Fellowship Program grant HST-HF2-51453.001 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. SD is the recipient of an Australian Research Council Discovery Early Career Award (DE210101738) funded by the Australian Government. GD, RK and MKr acknowledge support from European Research Council (ERC) Synergy Grant ‘BlackHoleCam’ Grant Agreement Number 610058 and ERC Advanced Grant ‘LEAP’ Grant Agreement Number 337062. TD is supported by the NSF AAG award number 2009468. ECF is supported by NASA under award number 80GSFC17M0002.002. BG is supported by the Italian Ministry of Education, University and Research within the PRIN 2017 Research Program Framework, n. 2017SYRTCN. Portions of this work performed at the Naval Research Laboratory is supported by NASA and ONR 6.1 basic research funding. MTL acknowledges support received from NSF AAG award number 200968. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. JWMK is a CITA Postdoctoral Fellow: This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), (funding reference CITA 490888-16). ASa, ASe, and GS acknowledge financial support provided under the European Union’s H2020 ERC Consolidator Grant ‘Binary Massive Black Hole Astrophysic’ (B Massive, Grant Agreement: 818691). RMS acknowledges support through Australian Research Council Future Fellowship FT190100155. JS acknowledges support from the JPL R&TD program. This research was funded partially by the Australian Government through the Australian Research Council (ARC), grants CE170100004 (OzGrav) and FL150100148. Pulsar research at UBC is supported by an NSERC Discovery Grant and by the Canadian Institute for Advanced Research. SRT acknowledges support from NSF grants AST-2007993 and PHY-2020265. SRT also acknowledges support from the Vanderbilt University College of Arts & Science Dean’s Faculty Fellowship program. AV acknowledges the support of the Royal Society and Wolfson Foundation. JPWV acknowledges support by the Deutsche Forschungsgemeinschaft (DFG) through the Heisenberg programme (Project No. 433075039). Author Contributions: An alphabetical-order author list was used for this paper to recognize the large amount of work and efforts contributed by many people within the IPTA consortium. All authors have contributed to the work via data creation, combination or analysis or contributions to the paper. The data set was created by a team led by BBPP, MED, PBD, MKe, LL, DJN, SO, SMR, and MJK, by combining data sets from the constituent PTAs (EPTA, NANOGrav, and PPTA). The data analysis has been the task of the Gravitational Wave Analysis Working Group (WG) of the IPTA. Many analyses have been performed over more than 2 yr by PTB, AC, SChe, JAE, JMG, JSH, KI, ADJ, WGL, CMFM, NSP, NKP, DJR, LSc, JS, LSp, SRT, and SJV under the leadership of several WG chairs over this time period: PTB, SChe, JSH, PDL, CMFM, DJR, and SRT. Initial tests, checks of the data quality and exploratory analyses were made by PTB, SChe, JAE, JMG, JSH, KI, CMFM, DJR, JS, SRT, and SJV. Although not much of the work is presented in this paper, it helped us tremendously in understanding the subtle details of the data set and built confidence in our analysis. The final results shown come from runs performed by AC, SChe, JSH, ADJ, WGL, NSP, NKP, ASa, LSc, GS, LSp, and SRT. The single pulsar noise analysis was done by SChe. The Bayesian parameter estimation were done by NSP, JSH, and WGL. The optimal statistic analysis was run by JSH and NSP, with help from AC, NKP, and LSp for the phase-shifts and sky-scramble null-distributions. ADJ and JSH have contributed to the Bayes factor computations. The factorized likelihood method has been applied to the data by LSc and SRT. NSP has computed the dropout factors. SChe performed the analyses of the constituent data sets, with cross-checks from ASa and GS. PTB lead the comparison between the IPTA DR2 and recent PTA data sets, which were graciously provided by JS for the NANOGrav 12.5 yr, BG for the PPTA DR2 and SChe for the EPTA DR2. The astrophysical interpretation was lead by JACC and CMFM with contributions from SChe and ASe. SChe lead the coordination of the paper writing with the help of JSH and PTB. PTB, JACC, SChe, MED, BG, JSH, CMFM, BBPP, NSP, LSc, RMS, SRT, and SJV contributed to the writing of the paper. The figures were created by NSP, JSH, JACC, and SChe. DATA AVAILABILITY. The timing data used can be found on https://gitlab.com/IPTA/DR2. Selected chain files for the analyses presented in this paper can be found on https://ipta4gw.org and 10.5281/zenodo.5787557.
Group:TAPIR
Funders:
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)ST/T000414/1
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Région CentreUNSPECIFIED
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Programme National de Cosmologie and Galaxies (PNCG)UNSPECIFIED
Institut National de Physique Nucléaire et de Physique des Particules (IN2P3)UNSPECIFIED
Institut National du Patrimoine (INP)UNSPECIFIED
Agence Nationale de la Recherche (ANR)ANR-18-CE31-0015
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)UNSPECIFIED
Agenzia Spaziale Italiana (ASI)UNSPECIFIED
Autonomous Region of SardiniaUNSPECIFIED
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
NSFPHY-1430284
Commonwealth Scientific and Research Organization (CSIRO)UNSPECIFIED
Stavros Niarchos FoundationUNSPECIFIED
Hellenic Foundation for Research and Innovation (HFRI)01431
NSFAST-1815664
National Astronomical Observatories, Chinese Academy of Sciences (NAOC)2020SKA0120100
National Natural Science Foundation of China11690024
NASA80NSSC20M0129
NSFPHY-2020265
NASA Hubble FellowshipHST-HF2-51453.001
NASANAS5-26555
Australian Research CouncilDE210101738
European Research Council (ERC)610058
European Research Council (ERC)337062
NSFAST-2009468
NASA80GSFC17M0002.002
Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR)2017SYRTCN
Naval Research Laboratory6.1 Base funding
NASA/JPL/CaltechUNSPECIFIED
Canadian Institute for Theoretical AstrophysicsUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)CITA 490888-16
European Research Council (ERC)818691
Australian Research CouncilFT190100155
JPL Research and Technology Development FundUNSPECIFIED
Australian Research CouncilCE170100004
Australian Research CouncilFL150100148
Canadian Institute for Advanced Research (CIFAR)UNSPECIFIED
NSFAST-2007993
Vanderbilt UniversityUNSPECIFIED
Royal SocietyUNSPECIFIED
Wolfson FoundationUNSPECIFIED
Deutsche Forschungsgemeinschaft (DFG)433075039
Subject Keywords:gravitational waves, methods: data analysis, pulsars: general
Issue or Number:4
DOI:10.1093/mnras/stab3418
Record Number:CaltechAUTHORS:20220329-726529570
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20220329-726529570
Official Citation:J Antoniadis, Z Arzoumanian, S Babak, M Bailes, A-S Bak Nielsen, P T Baker, C G Bassa, B Bécsy, A Berthereau, M Bonetti, A Brazier, P R Brook, M Burgay, S Burke-Spolaor, R N Caballero, J A Casey-Clyde, A Chalumeau, D J Champion, M Charisi, S Chatterjee, S Chen, I Cognard, J M Cordes, N J Cornish, F Crawford, H T Cromartie, K Crowter, S Dai, M E DeCesar, P B Demorest, G Desvignes, T Dolch, B Drachler, M Falxa, E C Ferrara, W Fiore, E Fonseca, J R Gair, N Garver-Daniels, B Goncharov, D C Good, E Graikou, L Guillemot, Y J Guo, J S Hazboun, G Hobbs, H Hu, K Islo, G H Janssen, R J Jennings, A D Johnson, M L Jones, A R Kaiser, D L Kaplan, R Karuppusamy, M J Keith, L Z Kelley, M Kerr, J S Key, M Kramer, M T Lam, W G Lamb, T J W Lazio, K J Lee, L Lentati, K Liu, J Luo, R S Lynch, A G Lyne, D R Madison, R A Main, R N Manchester, A McEwen, J W McKee, M A McLaughlin, M B Mickaliger, C M F Mingarelli, C Ng, D J Nice, S Osłowski, A Parthasarathy, T T Pennucci, B B P Perera, D Perrodin, A Petiteau, N S Pol, N K Porayko, A Possenti, S M Ransom, P S Ray, D J Reardon, C J Russell, A Samajdar, L M Sampson, S Sanidas, J M Sarkissian, K Schmitz, L Schult, A Sesana, G Shaifullah, R M Shannon, B J Shapiro-Albert, X Siemens, J Simon, T L Smith, L Speri, R Spiewak, I H Stairs, B W Stappers, D R Stinebring, J K Swiggum, S R Taylor, G Theureau, C Tiburzi, M Vallisneri, E van der Wateren, A Vecchio, J P W Verbiest, S J Vigeland, H Wahl, J B Wang, J Wang, L Wang, C A Witt, S Zhang, X J Zhu, The International Pulsar Timing Array second data release: Search for an isotropic gravitational wave background, Monthly Notices of the Royal Astronomical Society, Volume 510, Issue 4, March 2022, Pages 4873–4887, https://doi.org/10.1093/mnras/stab3418
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:114121
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:29 Mar 2022 12:27
Last Modified:04 Apr 2022 22:26

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  • Antoniadis, J. and Arzoumanian, Z. and Babak, S. and Bailes, M. and Bak Nielsen, A.-S. and Baker, P. T. and Bassa, C. G. and Bécsy, B. and Berthereau, A. and Bonetti, M. and Brazier, A. and Brook, P. R. and Burgay, M. and Burke-Spolaor, S. and Caballero, R. N. and Casey-Clyde, J. A. and Chalumeau, A. and Champion, D. J. and Charisi, M. and Chatterjee, S. and Chen, S. and Cognard, I. and Cordes, J. M. and Cornish, N. J. and Crawford, F. and Cromartie, H. T. and Crowter, K. and Dai, S. and DeCesar, M. E. and Demorest, P. B. and Desvignes, G. and Dolch, T. and Drachler, B. and Falxa, M. and Ferrara, E. C. and Fiore, W. and Fonseca, E. and Gair, J. R. and Garver-Daniels, N. and Goncharov, B. and Good, D. C. and Graikou, E. and Guillemot, L. and Guo, Y. J. and Hazboun, J. S. and Hobbs, G. and Hu, H. and Islo, K. and Janssen, G. H. and Jennings, R. J. and Johnson, A. D. and Jones, M. L. and Kaiser, A. R. and Kaplan, D. L. and Karuppusamy, R. and Keith, M. J. and Kelley, L. Z. and Kerr, M. and Key, J. S. and Kramer, M. and Lam, M. T. and Lamb, W. G. and Lazio, T. J. W. and Lee, K. J. and Lentati, L. and Liu, K. and Luo, J. and Lynch, R. S. and Lyne, A. G. and Madison, D. R. and Main, R. A. and Manchester, R. N. and McEwen, A. and McKee, J. W. and McLaughlin, M. A. and Mickaliger, M. B. and Mingarelli, C. M. F. and Ng, C. and Nice, D. J. and Osłowski, S. and Parthasarathy, A. and Pennucci, T. T. and Perera, B. B. P. and Perrodin, D. and Petiteau, A. and Pol, N. S. and Porayko, N. K. and Possenti, A. and Ransom, S. M. and Ray, P. S. and Reardon, D. J. and Russell, C. J. and Samajdar, A. and Sampson, L. M. and Sanidas, S. and Sarkissian, J. M. and Schmitz, K. and Schult, L. and Sesana, A. and Shaifullah, G. and Shannon, R. M. and Shapiro-Albert, B. J. and Siemens, X. and Simon, J. and Smith, T. L. and Speri, L. and Spiewak, R. and Stairs, I. H. and Stappers, B. W. and Stinebring, D. R. and Swiggum, J. K. and Taylor, S. R. and Theureau, G. and Tiburzi, C. and Vallisneri, M. and van der Wateren, E. and Vecchio, A. and Verbiest, J. P. W. and Vigeland, S. J. and Wahl, H. and Wang, J. B. and Wang, J. and Wang, L. and Witt, C. A. and Zhang, S. and Zhu, X. J. The International Pulsar Timing Array second data release: Search for an isotropic gravitational wave background. (deposited 29 Mar 2022 12:27) [Currently Displayed]

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