JWST and ALMA imaging of dust-obscured, massive substructures in a typical $z\sim 3$ star-forming disk galaxy

Abstract

We present an identification of dust-attenuated star-forming galactic-disk substructures in a typical star-forming galaxy (SFG), UDF2, at $z=2.696$. To date, substructures containing significant buildup of stellar mass and actively forming stars have yet to be found in typical (i.e., main-sequence) SFGs at $z>2$. This is due to the strong dust attenuation common in massive galaxies at the epoch and the scarcity of high-resolution, high-sensitivity extinction-independent imaging. To search for disk substructures, we subtracted the central stellar-mass disk from the JWST/NIRCam rest-frame 1.2 $\mu$m image ($0.13^{\prime \prime }$ resolution) and subtracted, in the visibility plane, the central starburst disk from ALMA rest-frame 240 $\mu$m observations ($0.03^{\prime \prime }$ resolution). The residual images revealed substructures at rest-frame 1.2 $\mu$m co-located with those found at rest-frame 240 $\mu$m, $\simeq 2$ kpc away from the galactic center. The largest substructure contains $\simeq 20$% of the total stellar mass and $\simeq 5$% of the total SFR of the galaxy. While UDF2 exhibits a kinematically-ordered velocity field of molecular gas consistent with a secularly evolving disk, more sensitive observations are required to characterize the nature and the origin of this substructure (spiral arms, minor merger, or other types of disk instabilities). UDF2 resides in an overdense region ($N⩾4$ massive galaxies within 70 kpc projected distance at $z=2.690-2.697$) and the substructures may be associated with interaction-induced instabilities. Importantly, a statistical sample of such substructures identified with JWST and ALMA could play a key role in bridging the gap between the bulge-forming starburst and the rest of the galaxy.

7 pages, 5 figures; ApJL, accepted

References in corpus (15)

• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• The Herschel view of the dominant mode of galaxy growth from z=4 to the present day
• A dynamically cold disk galaxy in the early Universe
• Sub-kpc ALMA imaging of compact star-forming galaxies at z~2.5: revealing the formation of dense galactic cores in the progenitors of compact quiescent galaxies
• VLA and ALMA Imaging of Intense, Galaxy-Wide Star Formation in z ~ 2 Galaxies
• Bulge-forming galaxies with an extended rotating disk at z~2
• Distinguishing Mergers and Disks in High Redshift Observations of Galaxy Kinematics
• Clumpy and Extended Starbursts in the Brightest Unlensed Submillimeter Galaxies
• The Identification of a Dusty Multiarm Spiral Galaxy at $z=3.06$ with JWST and ALMA
• A Comparison of the Stellar, CO and Dust-Continuum Emission from Three, Star-Forming HUDF Galaxies at $z\sim 2$
• JWST's PEARLS: A JWST/NIRCam view of ALMA sources
• Giant star-forming clumps?
• The role of gas fraction and feedback in the stability and evolution of galactic discs: implications for cosmological galaxy formation models
• Hierarchical fragmentation in high redshift galaxies revealed by hydrodynamical simulations
• Bulge formation inside quiescent lopsided stellar disks: connecting accretion, star formation and morphological transformation in a z ~ 3 galaxy group

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• Near-IR clumps and their properties in high-z galaxies with JWST/NIRCam
• JWST and ALMA discern the assembly of structural and obscured components in a high-redshift starburst galaxy
• JWST reveals extended stellar disks for ALMA-bright dusty star-forming galaxies in the Spiderweb protocluster
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