The Astrophysical Journal (Jan 2024)
JWST View of Four Infant Galaxies at z = 8.31–8.49 in the MACS J0416.1−2403 Field and Implications for Reionization
- Zhiyuan Ma,
- Bangzheng Sun,
- Cheng Cheng,
- Haojing Yan,
- Chenxiaoji Ling,
- Fengwu Sun,
- Nicholas Foo,
- Eiichi Egami,
- José M. Diego,
- Seth H. Cohen,
- Rolf A. Jansen,
- Jake Summers,
- Rogier A. Windhorst,
- Jordan C. J. D’Silva,
- Anton M. Koekemoer,
- Dan Coe,
- Christopher J. Conselice,
- Simon P. Driver,
- Brenda Frye,
- Norman A. Grogin,
- Madeline A. Marshall,
- Mario Nonino,
- Rafael Ortiz III,
- Nor Pirzkal,
- Aaron Robotham,
- Russell E. Ryan Jr,
- Christopher N. A. Willmer,
- Nathan J. Adams,
- Nimish P. Hathi,
- Hervé Dole,
- S. P. Willner,
- Daniel Espada,
- Lukas J. Furtak,
- Tiger Yu-Yang Hsiao,
- Qiong Li,
- Wenlei Chen,
- Jean-Baptiste Jolly,
- Chian-Chou Chen
Affiliations
- Zhiyuan Ma
- ORCiD
- Department of Astronomy, University of Massachusetts , Amherst, MA 01003, USA
- Bangzheng Sun
- ORCiD
- Department of Physics and Astronomy, University of Missouri , Columbia, MO 65211, USA ; [email protected]
- Cheng Cheng
- ORCiD
- Chinese Academy of Sciences South America Center for Astronomy , National Astronomical Observatories, Chinese Academy of Science, Beijing 100101, People's Republic of China
- Haojing Yan
- ORCiD
- Department of Physics and Astronomy, University of Missouri , Columbia, MO 65211, USA ; [email protected]
- Chenxiaoji Ling
- ORCiD
- National Astronomical Observatories , Chinese Academy of Science, Beijing 100101, People's Republic of China
- Fengwu Sun
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA; Steward Observatory, University of Arizona , 933 N Cherry Avenue, Tucson, AZ 85721-0009, USA
- Nicholas Foo
- ORCiD
- School of Earth and Space Exploration, Arizona State University , Tempe, AZ 85287-1404, USA
- Eiichi Egami
- ORCiD
- Steward Observatory, University of Arizona , 933 N Cherry Avenue, Tucson, AZ 85721-0009, USA
- José M. Diego
- ORCiD
- Instituto de Física de Cantabria (CSIC-UC ), Avda. Los Castros s/n, 39005 Santander, Spain
- Seth H. Cohen
- ORCiD
- School of Earth and Space Exploration, Arizona State University , Tempe, AZ 85287-1404, USA
- Rolf A. Jansen
- ORCiD
- School of Earth and Space Exploration, Arizona State University , Tempe, AZ 85287-1404, USA
- Jake Summers
- ORCiD
- School of Earth and Space Exploration, Arizona State University , Tempe, AZ 85287-1404, USA
- Rogier A. Windhorst
- ORCiD
- School of Earth and Space Exploration, Arizona State University , Tempe, AZ 85287-1404, USA
- Jordan C. J. D’Silva
- ORCiD
- International Centre for Radio Astronomy Research (ICRAR) and the International Space Centre (ISC), The University of Western Australia , M468, 35 Stirling Highway, Crawley, WA 6009, Australia; ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) , Australia
- Anton M. Koekemoer
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Dan Coe
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Association of Universities for Research in Astronomy (AURA) for the European Space Agency (ESA) , Space Telescope Science Institute, Baltimore, MD 21218, USA; Center for Astrophysical Sciences, Department of Physics and Astronomy, The Johns Hopkins University , 3400 N Charles St., Baltimore, MD 21218, USA
- Christopher J. Conselice
- ORCiD
- Jodrell Bank Centre for Astrophysics, Alan Turing Building, University of Manchester , Oxford Road, Manchester M13 9PL, UK
- Simon P. Driver
- ORCiD
- International Centre for Radio Astronomy Research (ICRAR) and the International Space Centre (ISC), The University of Western Australia , M468, 35 Stirling Highway, Crawley, WA 6009, Australia
- Brenda Frye
- ORCiD
- Department of Astronomy/Steward Observatory, University of Arizona , 933 N Cherry Avenue, Tucson, AZ 85721-0009, USA
- Norman A. Grogin
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Madeline A. Marshall
- ORCiD
- ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) , Australia; National Research Council of Canada, Herzberg Astronomy & Astrophysics Research Centre , 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada
- Mario Nonino
- ORCiD
- INAF-Osservatorio Astronomico di Trieste , Via Bazzoni 2, 34124 Trieste, Italy
- Rafael Ortiz III
- ORCiD
- School of Earth and Space Exploration, Arizona State University , Tempe, AZ 85287-1404, USA
- Nor Pirzkal
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Aaron Robotham
- ORCiD
- International Centre for Radio Astronomy Research (ICRAR) and the International Space Centre (ISC), The University of Western Australia , M468, 35 Stirling Highway, Crawley, WA 6009, Australia
- Russell E. Ryan Jr
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Christopher N. A. Willmer
- ORCiD
- Steward Observatory, University of Arizona , 933 N Cherry Avenue, Tucson, AZ 85721-0009, USA
- Nathan J. Adams
- ORCiD
- Jodrell Bank Centre for Astrophysics, Alan Turing Building, University of Manchester , Oxford Road, Manchester M13 9PL, UK
- Nimish P. Hathi
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Hervé Dole
- ORCiD
- Université Paris-Saclay , CNRS, Institut d’Astrophysique Spatiale, 91405 Orsay, France
- S. P. Willner
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Daniel Espada
- ORCiD
- Departamento de Física Teórica y del Cosmos, Campus de Fuentenueva, Edificio Mecenas, Universidad de Granada , E-18071 Granada, Spain; Instituto Carlos I de Física Teórica y Computacional , Facultad de Ciencias, E-18071 Granada, Spain
- Lukas J. Furtak
- ORCiD
- Physics Department, Ben-Gurion University of the Negev , P.O. Box 653, Beer-Sheva 8410501, Israel
- Tiger Yu-Yang Hsiao
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Center for Astrophysical Sciences, Department of Physics and Astronomy, The Johns Hopkins University , 3400 N Charles St., Baltimore, MD 21218, USA
- Qiong Li
- ORCiD
- Jodrell Bank Centre for Astrophysics, Alan Turing Building, University of Manchester , Oxford Road, Manchester M13 9PL, UK
- Wenlei Chen
- ORCiD
- Department of Physics, Oklahoma State University , 145 Physical Sciences Bldg, Stillwater, OK 74078, USA
- Jean-Baptiste Jolly
- ORCiD
- Max-Planck-Institut für Extraterrestrische Physik (MPE) , Giessenbachstraße 1, D-85748 Garching, Germany
- Chian-Chou Chen
- ORCiD
- Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) , No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
- DOI
- https://doi.org/10.3847/1538-4357/ad7b32
- Journal volume & issue
-
Vol. 975,
no. 1
p. 87
Abstract
New JWST/NIRCam wide-field slitless spectroscopy provides redshifts for four z > 8 galaxies located behind the lensing cluster MACS J0416.1−2403. Two of them, “Y1” and “JD,” have previously reported spectroscopic redshifts based on Atacama Large Millimeter/submillimeter Array measurements of [O iii ] 88 μ m and/or [C ii ] 157.7 μ m lines. Y1 is a merging system of three components, and the existing redshift z = 8.31 is confirmed. However, JD is at z = 8.34 instead of the previously claimed z = 9.28. JD’s close companion, “JD-N,” which was a previously discovered z > 8 candidate, is now identified at the same redshift as JD. JD and JD-N form an interacting pair. A new candidate at z > 8, “f090d_018,” is also confirmed and is at z = 8.49. These four objects are likely part of an overdensity that signposts a large structure extending ∼165 kpc in projected distance and ∼48.7 Mpc in radial distance. They are magnified by less than 1 mag and have an intrinsic M _UV ranging from −19.57 to −20.83 mag. Their spectral energy distributions show that the galaxies are all very young with ages ∼ 4–18 Myr and stellar masses of about 10 ^7–8 M _⊙ . These infant galaxies have very different star formation rates ranging from a few to over a hundred solar masses per year, but only two of them (JD and f090d_018) have blue rest-frame UV slopes β < −2.0 indicative of a high Lyman-continuum photon escape fraction that could contribute significantly to the cosmic hydrogen-reionizing background. Interestingly, these two galaxies are the least massive and least active ones among the four. The other two systems have much flatter UV slopes largely because of their high dust extinction ( A _V = 0.9–1.0 mag). Their much lower indicated escape fractions show that even very young, actively star-forming galaxies can have a negligible contribution to reionization when they quickly form dust throughout their bodies.
Keywords
