Imaging of I Zw 18 by JWST. I. Detecting Dusty Stellar Populations
Artikel i vetenskaplig tidskrift, 2024

We present a JWST imaging survey of I Zw 18, the archetypal extremely metal-poor, star-forming (SF), blue compact dwarf galaxy. With an oxygen abundance of only similar to 3% Z circle dot, it is among the lowest-metallicity systems known in the local Universe, and is, therefore, an excellent accessible analog for the galactic building blocks which existed at early epochs of ionization and star formation. These JWST data provide a comprehensive infrared (IR) view of I Zw 18 with eight filters utilizing both Near Infrared Camera (F115W, F200W, F356W, and F444W) and Mid-Infrared Instrument (F770W, F1000W, F1500W, and F1800W) photometry, which we have used to identify key stellar populations that are bright in the near- and mid-IR. These data allow for a better understanding of the origins of dust and dust-production mechanisms in metal-poor environments by characterizing the population of massive, evolved stars in the red supergiant (RSG) and asymptotic giant branch (AGB) phases. In addition, it enables the identification of the brightest dust-enshrouded young stellar objects (YSOs), which provide insight into the formation of massive stars at extremely low metallicities typical of the very early Universe. This paper provides an overview of the observational strategy and data processing, and presents first science results, including identifications of dusty AGB, RSG, and bright YSO candidates. These first results assess the scientific quality of JWST data and provide a guide for obtaining and interpreting future observations of the dusty and evolved stars inhabiting compact dwarf SF galaxies in the local Universe.


Alec S. Hirschauer

Space Telescope Science Institute (STScI)

Nicolas Crouzet

Universiteit Leiden

Nolan Habel

California Institute of Technology (Caltech)

Laura Lenkic

California Institute of Technology (Caltech)

NASA Ames Res Ctr, Stratospher Observ Infrared Astron, Mail Stop 204-14

Conor Nally

University of Edinburgh

Olivia C. Jones

UK Astron Technol Ctr

Giacomo Bortolini

Stockholms universitet

Martha L. Boyer

Space Telescope Science Institute (STScI)

Kay Justtanont

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

Margaret Meixner

California Institute of Technology (Caltech)

Goran Ostlin

Stockholms universitet

Gillian S. Wright

UK Astron Technol Ctr

Ruyman Azzollini

University College London (UCL)

Joris A. D. L. Blommaert

Vrije Universiteit Brüssel (VUB)

Bernhard Brandl

Universiteit Leiden

Leen Decin

Katholieke Univ Leuven

Omnarayani Nayak

NASA Goddard Space Flight Center

Space Telescope Science Institute (STScI)

Pierre Royer

Katholieke Univ Leuven

B. A. Sargent

Space Telescope Science Institute (STScI)

Johns Hopkins University

Paul van der Werf

Universiteit Leiden

Astronomical Journal

0004-6256 (ISSN) 1538-3881 (eISSN)

Vol. 168 1 23


Astronomi, astrofysik och kosmologi

Datorseende och robotik (autonoma system)



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