Open clusters and associations: individual: Westerlund 1; Stars: formation; Stars: low-mass; Stars: massive; Stars: Wolf-Rayet; X-rays: stars; Cluster survey; Massive stars; Open clusters; Stars formation; Stars: low mass; X-ray sources; X-ray:stars; Astronomy and Astrophysics; Space and Planetary Science
Abstract :
[en] Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions among stars. Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars. The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun. Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically, the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec. Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation were carried out using the ACIS-Extract software. Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a photon flux threshold of approximately 2 × 10-8 photons cm-2 s-1. The X-ray sources exhibit a highly concentrated spatial distribution, with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Guarcello, M.G. ; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy
Flaccomio, E. ; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy
Albacete-Colombo, J.F.; Universidad de Rio Negro, Sede Atlántica - Conicet, Río Negro, Argentina
Almendros-Abad, V. ; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy
Anastasopoulou, K. ; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy
Andersen, M.; European Southern Observatory, Garching bei München, Germany
Argiroffi, C.; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy ; Department of Physics and Chemistry, University of Palermo, Palermo, Italy
Bayo, A. ; European Southern Observatory, Garching bei München, Germany
Bartlett, E.S.; European Southern Observatory, Garching bei München, Germany
Bastian, N.; Donostia International Physics Center (DIPC), Guipuzkoa, Spain ; Ikerbasque, Basque Foundation for Science, Bilbao, Spain ; Astrophysics Research Institute, Liverpool John Moores University, IC2 Liverpool Science Park, Liverpool, United Kingdom
De Becker, Michaël ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Sciences spatiales
Best, W. ; Department of Astronomy, University of Texas at Austin, Austin, United States
Bonito, R.; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy
Borghese, A. ; Instituto de Astrofísica de Canarias, La Laguna, Spain ; Departamento de Astrofísica, Universidad de la Laguna, La Laguna, Spain
Calzetti, D.; Department of Astronomy, University of Massachusetts, Amherst, United States
Castellanos, R. ; Departamento de Astrofísica, Centro de Astrobiología, (CSIC-INTA), Madrid, Spain
Cecchi-Pestellini, C.; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy
Clark, J.S.; School of Physical Sciences, The Open University, Milton Keynes, United Kingdom
Clarke, C.J.; Institute of Astronomy, University of Cambridge, Cambridge, United Kingdom
Zelati, F. Coti ; Institute of Space Sciences (ICE, CSIC), Campus Uab, Barcelona, Spain ; Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona, Spain
Damiani, F.; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy
Drake, J.J. ; Center for Astrophysics | Harvard and Smithsonian, Cambridge, United States
Gennaro, M. ; Space Telescope Science Institute, Baltimore, United States ; The William H. Miller Iii Department of Physics and Astronomy, Bloomberg Center for Physics and Astronomy, Johns Hopkins University, Baltimore, United States
Ginsburg, A.; Department of Astronomy, University of Florida, Gainesville, United States
Grebel, E.K.; Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Heidelberg, Germany
Hora, J.L. ; Center for Astrophysics | Harvard and Smithsonian, Cambridge, United States
Israel, G.L.; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Roma, Monte Porzio Catone, Italy
Lawrence, G. ; Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Australia ; Department of Physics and Astronomy, University College London, London, United Kingdom
Locci, D.; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy
Mapelli, M.; Universität Heidelberg, Zentrum für Astronomie, Institut für The-oretische Astrophysik, Heidelberg, Germany ; Physics and Astronomy Department Galileo Galilei, University of Padova, Padova, Italy
Martinez-Galarza, J.R.; Center for Astrophysics | Harvard and Smithsonian, Cambridge, United States
Micela, G.; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy
Miceli, M.; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy ; Department of Physics and Chemistry, University of Palermo, Palermo, Italy
Moraux, E.; Univ. Grenoble-Alpes, Cnrs, Ipag, Grenoble, France
Muzic, K.; Instituto de Astrofísica e Ciências Do Espaço, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
Najarro, F.; Departamento de Astrofísica, Centro de Astrobiología, (CSIC-INTA), Madrid, Spain
Negueruela, I. ; Departamento de Física Aplicada, Facultad de Ciencias, Universidad de Alicante, San Vicente del Raspeig, Spain
Nota, A.; Space Telescope Science Institute, Baltimore, United States
Pallanca, C.; Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna, Italy ; Istituto Nazionale di Astrofisica (INAF), Osservatorio di Astrofisica e Scienza Dello Spazio di Bologna, Bologna, Italy
Prisinzano, L. ; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy
Ritchie, B. ; School of Physical Sciences, The Open University, Milton Keynes, United Kingdom
Robberto, M.; Space Telescope Science Institute, Baltimore, United States ; Johns Hopkins University, Baltimore, United States
Rom, T. ; Univ. Grenoble-Alpes, Cnrs, Ipag, Grenoble, France ; University of Split, Faculty of Science, Department of Physics, Split, Croatia
Sabbi, E.; Space Telescope Science Institute, Baltimore, United States
Scholz, A.; School of Physics and Astronomy, University of St Andrews, St Andrews, United Kingdom
Sciortino, S.; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Palermo, Palermo, Italy
Trigilio, C. ; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astrofisico di Catania, Catania, Italy
Umana, G.; Istituto Nazionale di Astrofisica (INAF), Osservatorio Astrofisico di Catania, Catania, Italy
Winter, A.; Université Côte d'Azur, Observatoire de la Côte d'Azur, Cnrs, Laboratoire Lagrange, Nice, France ; Université Grenoble Alpes, Cnrs, Ipag, Grenoble, France
Wright, N.J.; Astrophysics Group, Keele University, Staffordshire, United Kingdom
Zeidler, P. ; Aura for the European Space Agency (ESA), Esa Office, Space Telescope Science Institute, Baltimore, United States
INAF - Istituto Nazionale di Astrofisica FCT - Fundação para a Ciência e a Tecnologia NASA - National Aeronautics and Space Administration MICINN - Ministerio de Ciencia e Innovacion EU - European Union ERC - European Research Council BMBF - Bundesministerium für Bildung und Forschung
Funding text :
We acknowledge the referee for his/her careful reading of our paper and suggestions. M.G.G. is also indebted to Leisa K. Townsley and Patrick S. Broos for their valuable suggestions and advice on data reduction and ACIS extraction. M.G.G., C.A., R.B., E.F., G.L.I., L.P., and S.S. acknowledge the INAF grant 1.05.12.05.03. K.M. acknowledges support from the Fundação para a Ciência e a Tecnologia (FCT) through the CEEC-individual contract 2022.03809.CEECIND and research grants UIDB/04434/2020 and UIDP/04434/2020. Support for this work was also provided by the National Aeronautics and Space Administration through Chandra Proposal 21200267 issued by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. I.N. is partially supported by the Spanish Government Ministerio de Ciencia e Innovación (MCIN) and Agencia Estatal de Investigación (MCIN/AEI/10.130 39/501 100 011 033/FEDER, UE) under grant PID2021-122397NB-C22, and also by MCIN with funding from the European Union NextGenerationEU and Generalitat Valenciana in the call Programa de Planes Complementarios de I+D+i (PRTR 2022), project HIAMAS, reference ASFAE/2022/017. M. G. G. and R. B. acknowledge partial support from the Grant INAF 2022 YODA; R. B. also acknowledges partial support from the project PRIN-INAF 2019 "Spectroscopically Tracing the Disk Dispersal Evolution". The scientific results reported in this article are based on observations made by the Chandra X-ray Observatory. M.M. acknowledges financial support from the European Research Council for the ERC Consolidator grant DEMOBLACK, under contract no. 770017, and from the German Excellence Strategy via the Heidelberg Cluster of Excellence (EXC 2181 - 390900948) STRUCTURES.We acknowledge the referee for his/her careful reading of our paper and suggestions. M.G.G. is also indebted to Leisa K. Townsley and Patrick S. Broos for their valuable suggestions and advice on data reduction and ACIS extraction. M.G.G., C.A., R.B., E.F., G.L.I., L.P., and S.S. acknowledge the INAF grant 1.05.12.05.03. K.M. acknowledges support from the Fundação para a Ciência e a Tecnologia (FCT) through the CEEC-individual contract 2022.03809.CEECIND and research grants UIDB/04434/2020 and UIDP/04434/2020. Support for this work was also provided by the National Aeronautics and Space Administration through Chandra Proposal 21200267 issued by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. I.N. is partially supported by the Spanish Government Ministerio de Ciencia e Innovación (MCIN) and Agencia Estatal de Investigación (MCIN/AEI/10.130 39/501 100 011 033/FEDER, UE) under grant PID2021-122397NB-C22, and also by MCIN with funding from the European Union NextGenerationEU and Generalitat Valenciana in the call Pro-grama de Planes Complementarios de I + D + i (PRTR 2022), project HIAMAS, reference ASFAE/2022/017. M. G. G. and R. B. acknowledge partial support from the Grant INAF 2022 YODA; R. B. also acknowledges partial support from the project PRIN-INAF 2019 “Spectroscopically Tracing the Disk Dispersal Evolution”. The scientific results reported in this article are based on observations made by the Chandra X-ray Observatory. M.M. acknowledges financial support from the European Research Council for the ERC Consolidator grant DEMOBLACK, under contract no. 770017, and from the German Excellence Strategy via the Heidelberg Cluster of Excellence (EXC 2181 – 390900948) STRUCTURES. European Union NextGeneration; German Excellence Strategy
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