Produção Nacional
Revisado por pares
JWST Reveals a Possible z ∼ 11 Galaxy Merger in Triply Lensed MACS0647–JD
2023; IOP Publishing; Volume: 949; Issue: 2 Linguagem: Inglês
10.3847/2041-8213/acc94b
ISSN2041-8213
AutoresTiger Yu-Yang Hsiao, Dan Coe, Abdurrouf, Lily Whitler, Intae Jung, Gourav Khullar, Ashish Kumar Meena, Pratika Dayal, Kirk S. S. Barrow, Lillian Santos-Olmsted, Adam Casselman, E. Vanzella, M. Nonino, Y. Jiménez-Teja, Masamune Oguri, Daniel P. Stark, Lukas J. Furtak, Adi Zitrin, Angela Adamo, Gabriel Brammer, Larry Bradley, J. M. Diego, Erik Zackrisson, Steven L. Finkelstein, Rogier A. Windhorst, Rachana Bhatawdekar, Taylor A. Hutchison, Tom Broadhurst, Paola Dimauro, Felipe Andrade-Santos, J. J. Eldridge, Ana Acebrón, Roberto J. Avila, Matthew Bayliss, Alex Benítez, Christian Binggeli, Patricia Bolan, Maruša Bradač, A C Carnall, Christopher J. Conselice, Megan Donahue, Brenda Frye, Seiji Fujimoto, Alaina Henry, Bethan L. James, Susan A. Kassin, Lisa J. Kewley, Rebecca L. Larson, Tod R. Lauer, David R. Law, Guillaume Mahler, Ramesh Mainali, Stephan R. McCandliss, David C. Nicholls, N. Pirzkal, Marc Postman, Jane R. Rigby, Russell E. Ryan, Peter Senchyna, Keren Sharon, Ikko Shimizu, Victoria Strait, Mengtao Tang, Michele Trenti, Anton Vikaeus, Brian Welch,
Tópico(s)Astronomy and Astrophysical Research
ResumoMACS0647$-$JD is a triply-lensed $z\sim11$ galaxy originally discovered with the 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. Both are very small, with stellar masses $\sim10^8\,M_\odot$ and radii $r<100\,\rm pc$. 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 ($100-200\,\rm Myr$) with mild dust extinction ($A_V\sim0.1\,\rm mag$), 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. With an estimated stellar mass ratio of roughly 2:1 and physical projected separation $\sim400\,\rm pc$, we may be witnessing a galaxy merger 400 million years after the Big Bang. We also identify a candidate companion galaxy C $\sim3\,{\rm kpc}$ away, likely destined to merge with galaxies A and B. The combined light from galaxies A+B is magnified by factors of $\sim$8, 5, and 2 in three lensed images JD1, 2, and 3 with F356W fluxes $\sim322$, $203$, $86\,\rm nJy$ (AB mag 25.1, 25.6, 26.6). MACS0647$-$JD is significantly brighter than other galaxies recently discovered at similar redshifts with JWST. Without magnification, it would have AB mag 27.3 ($M_{UV}=-20.4$). With a high confidence level, we obtain a photometric redshift of $z=10.6\pm0.3$ based on photometry measured in 6 NIRCam filters spanning $1-5\rm\mu m$, out to $4300\,\r{A}$ rest-frame. JWST NIRSpec observations planned for January 2023 will deliver a spectroscopic redshift and a more detailed study of the physical properties of MACS0647$-$JD.
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