PANORAMIC: Discovery of an ultra-massive grand-design spiral galaxy at <i>z</i> ∼ 5.2

We report the discovery of an ultra-massive grand-design red spiral galaxy, named Zhúlóng (Torch Dragon), at z phot = 5.2 −0.2 +0.3 in the JWST PANORAMIC survey; it is the most distant bulge+disk galaxy candidate with spiral arms known to date. Zhúlóng displays an extraordinary combination of properties: (1) a classical bulge centered in a large, face-on exponential stellar disk (half-light radius of R e = 3.7 ± 0.1 kpc) with spiral arms extending across 19 kpc; (2) a clear transition from the red, quiescent core ( F 150 W − F 444 W = 3.1 mag) with a high stellar mass surface density (log(Σ M ⋆ / M ⊙ kpc −2 ) = 9.91 −0.09 +0.11 ) to the star-forming outer regions, as revealed by spatially resolved spectral energy distribution analysis, which indicates significant inside-out galaxy growth; (3) an extremely high stellar mass for its redshift, with log( M ⋆ / M ⊙ ) = 11.03 −0.08 +0.10 , which is comparable to the Milky Way’s mass, and an implied baryon-to-star conversion efficiency ( ϵ ∼ 0.3) that is 1.5 times higher than even the most efficient galaxies at later epochs; and (4) despite an active disk, a relatively modest overall star formation rate (SFR = 66 −46 +89 M ⊙ yr −1 ), which is &gt; 0.5 dex below the star formation main sequence at z ∼ 5.2 and &gt; 10 times lower than ultra-massive dusty galaxies at z = 5 − 6. Zhúlóng shows that mature galaxies emerged much earlier than previously believed, in the first billion years after the Big Bang, through rapid galaxy formation and morphological evolution. Our finding offers key constraints for models of massive galaxy formation and the origin of spiral structures in the early Universe.

Authors

Institutions

Publication Details

Journal
Astronomy and Astrophysics
Published
2025-03-17
DOI
https://doi.org/10.1051/0004-6361/202453487
Citations
8
Primary Topic
Galaxies: Formation, Evolution, Phenomena
Type
article
Field-Weighted Citation Impact
9.24

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

PANORAMIC: Discovery of an ultra-massive grand-design spiral galaxy at z ∼ 5.2

Zhiyuan Ji, R. Marques-Chaves, Marijn Franx, D. Elbaz et al.
8 citations
Astronomy and Astrophysics
Galaxies: Formation, Evolution, Phenomena
9.24
article

PANORAMIC: Discovery of an ultra-massive grand-design spiral galaxy at z ∼ 5.2

Zhiyuan Ji, R. Marques-Chaves, Marijn Franx, D. Elbaz, Rachel Bezanson, Felix Martinez, Karl Glazebrook, G. Lagache, Seunghwan Lim, M. Dessauges‐Zavadsky, Caitlin M. Casey, Christina C. Williams, D. Schaerer, L. Bing, Pascal A. Oesch, Emanuele Daddi, Gabriel Brammer, Michael V. Maseda, Anne Hutter, B. Magnelli, Katherine E. Whitaker, Mengyuan Xiao, Andrea Weibel, Andreas L. Faisst, Jeyhan S. Kartaltepe, Ivo Labbé, Themiya Nanayakkara, Pratika Dayal, Aidan P. Cloonan
article en
8 citations

Abstract

We report the discovery of an ultra-massive grand-design red spiral galaxy, named Zhúlóng (Torch Dragon), at z phot = 5.2 −0.2 +0.3 in the JWST PANORAMIC survey; it is the most distant bulge+disk galaxy candidate with spiral arms known to date. Zhúlóng displays an extraordinary combination of properties: (1) a classical bulge centered in a large, face-on exponential stellar disk (half-light radius of R e = 3.7 ± 0.1 kpc) with spiral arms extending across 19 kpc; (2) a clear transition from the red, quiescent core ( F 150 W − F 444 W = 3.1 mag) with a high stellar mass surface density (log(Σ M ⋆ / M ⊙ kpc −2 ) = 9.91 −0.09 +0.11 ) to the star-forming outer regions, as revealed by spatially resolved spectral energy distribution analysis, which indicates significant inside-out galaxy growth; (3) an extremely high stellar mass for its redshift, with log( M ⋆ / M ⊙ ) = 11.03 −0.08 +0.10 , which is comparable to the Milky Way’s mass, and an implied baryon-to-star conversion efficiency ( ϵ ∼ 0.3) that is 1.5 times higher than even the most efficient galaxies at later epochs; and (4) despite an active disk, a relatively modest overall star formation rate (SFR = 66 −46 +89 M ⊙ yr −1 ), which is &gt; 0.5 dex below the star formation main sequence at z ∼ 5.2 and &gt; 10 times lower than ultra-massive dusty galaxies at z = 5 − 6. Zhúlóng shows that mature galaxies emerged much earlier than previously believed, in the first billion years after the Big Bang, through rapid galaxy formation and morphological evolution. Our finding offers key constraints for models of massive galaxy formation and the origin of spiral structures in the early Universe.

Astronomy and AstrophysicsVol. 696
Damien Foundation (BD)
National Science Foundation, National Aeronautics and Space Administration, University of Arizona, Space Telescope Science Institute, UK Research and Innovation, National Radio Astronomy Observatory, European Commission, National Research Foundation, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Rijksuniversiteit Groningen, Danmarks Grundforskningsfond, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Korea Astronomy and Space Science Institute, National Astronomical Observatory of Japan, National Science and Technology Council, Science and Technology Facilities Council, National Institutes of Natural Sciences, Staatssekretariat für Bildung, Forschung und Innovation
Affordable and clean energy
Openalex Percentile: Top 2%
Galaxies: Formation, Evolution, Phenomena
9.24
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.