Year: 2023
Type: article
Abstract: Galaxies have formed from the repeated mergers of small star-forming clumps over cosmic time, with some small galaxies left over even today, such as the Magellanic clouds. JWST has now discovered two such small galaxies within the first 430 billion years, that are seen close to the very start of this process. MACS0647--JD is a triply-lensed $z \sim 11$ galaxy originally discovered with the \emph{Hubble Space Telescope}. Here we report new JWST imaging, which clearly resolves MACS0647--JD as having two components that are either merging galaxies or stellar complexes within a single galaxy. The brighter larger component ``A'' is intrinsically very blue ($\beta \sim -2.6$), likely due to very recent star formation and no dust, and is spatially extended with an effective radius $\sim70\,{\rm pc}$. The smaller component ``B'' appears redder ($\beta \sim -2$), likely because it is older (100--200\,Myr) with mild dust extinction ($A_V \sim 0.1$\,mag), and a smaller radius $\sim20\,{\rm pc}$. We identify galaxies with similar colors in a high-redshift simulation, finding their star formation histories to be out of phase. JWST NIRSpec observations planned for January 2023 will deliver a spectroscopic redshift and a more detailed study of the physical properties of MACS0647--JD.
Authors: Tiger Yu-Yang Hsiao, Dan Coe, Abdurro'uf Abdurro'uf, Lily Whitler, Intae Jung, Gourav Khullar, Ashish Kumar Meena, Pratika Dayal, Kirk Barrow, Lillian Santos-Olmsted, Adam Casselman, Eros Vanzella, Mario Nonino, Yolanda Jimenez-Teja, Masamune Oguri, Daniel Stark, Lukas Furtak, Adi Zitrin, Angela Adamo, Gabriel Brammer, Larry Bradley, Jose M. Diego, Erik Zackrisson, Steven Finkelstein, Rogier Windhorst, Rachana Bhatawdekar, Taylor Hutchison, Thomas Broadhurst, Paola Dimauro, Felipe Andrade-Santos, Jan Eldridge, Ana Acebron, Roberto Avila, Matthew Bayliss, Alex Benitez, Christian Binggeli, Patricia Bolan, Marusa Bradac, Adam Carnall, Christopher Conselice, Megan Donahue, Brenda Frye, Seiji Fujimoto, Alaina Henry, Bethan James, Susan Kassin, Lisa Kewley, Rebecca Larson, Tod Lauer, David Law, Guillaume Mahler, Ramesh Mainali, Stephan McCandliss, David Nicholls, Norbert Pirzkal, Marc Postman, Jane Rigby, Russell Ryan, Peter Senchyna, Keren Sharon, Ikko Shimizu, Victoria Strait, Mengtao Tang, Michele Trenti, Anton Vikaeus, Brian Welch
Institutions: Johns Hopkins University, Space Telescope Science Institute, Association of Universities for Research in Astronomy, European Space Agency, University of Arizona, University of Pittsburgh, Ben-Gurion University of the Negev, University of Groningen, University of Illinois Urbana-Champaign, Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Osservatorio di Astrofisica e Scienza dello Spazio, National Institute for Astrophysics, Trieste Astronomical Observatory, National Observatory, Instituto de Astrofísica de Andalucía, Chiba University, Center for Frontier Science, Chiba University, Stockholm University, AlbaNova, University of Copenhagen, Consejo Superior de Investigaciones Científicas, Instituto de Física de Cantabria, Uppsala University, The University of Texas at Austin, Arizona State University, European Space Research and Technology Centre, Goddard Space Flight Center, Ikerbasque, University of the Basque Country, Donostia International Physics Center, Astronomical Observatory of Rome, Berklee College of Music, Center for Astrophysics Harvard & Smithsonian, University of Auckland, University of Milan, University of Cincinnati, University of London, King's College London, University of California, Davis, University of Ljubljana, Royal Observatory, University of Edinburgh, University of Manchester, Michigan State University, NSF NOIRLab, Durham University, Australian National University, ASTRO-3D, ARC Centre of Excellence for All-sky Astrophysics, Carnegie Observatories, University of Michigan, Shikoku Gakuin University, University College London, The University of Melbourne, University of Maryland, College Park
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
Funders: National Science Foundation, National Aeronautics and Space Administration, Space Telescope Science Institute, Ministerio de Ciencia, Innovación y Universidades, Leverhulme Trust, European Commission, National Research Foundation, Rijksuniversiteit Groningen, Danmarks Grundforskningsfond, United States-Israel Binational Science Foundation, Swedish National Space Agency, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Ministero dell’Istruzione, dell’Università e della Ricerca, Javna Agencija za Raziskovalno Dejavnost RS, Vetenskapsrådet, Instituto de Astrofísica de Andalucía, Science and Technology Facilities Council, Japan Society for the Promotion of Science, Consejo Superior de Investigaciones Científicas
Awards: G103270039, G112473895, Astrophysics and Cosmology Research at the Jodrell Bank Centre for Astrophysics 2023-2026, G1338664626, G1459069146, G1712102273, G1735320636, Exploring Cosmic Dawn with James Webb Space Telescope, G256731684, G2723981421, G2981755126, G3076547670, G3248903251, Wide Field Astronomical Survey by high Speed CMOS, G3975875632, Graduate Research Fellowship Program (GRFP), Accurate measurements of the Hubble constant with multi-faceted gravitational lensing analyses, G5513975304, G5568641063, Unveiling the formation and evolution of galaxy clusters through the intracluster light and multidisciplinar techniques of image processing and big data analysis, ODIN: a framework to shed light on Dark Matter and the era of cosmic dawn, 十六世紀を中心とした畿内村落の基礎構造, G6880300208, Comprehensive understanding of the formation history of structures in the Universe, Zooming into Dark Matter and proto-galaxies with massive lensing clusters, NSF-BSF: Galaxies in the Reionization Era, G7722401655, G785121043, Star formation within evolving galaxies: the revolution of the James Webb Space Telescope, G8067020961, G8355605048, G8380842850, G8552695075, G8670261954
OpenAlex ID: W4379230091