Hidden giants in JWST's PEARLS: An ultra-massive z=4.26 sub-millimeter galaxy that is invisible to HST

Ian Smail; Ugne Dudzeviciute; Mark Gurwell; Giovanni G. Fazio; S. P. Willner; A. M. Swinbank; Vinodiran Arumugam; Jake Summers; Seth H. Cohen; Rolf A. Jansen; Rogier A. Windhorst; Ashish Meena; Adi Zitrin; William C. Keel; Dan Coe; Christopher J. Conselice; Jordan C. J. D'Silva; Simon P. Driver; Brenda Frye; Norman A. Grogin; Anton M. Koekemoer; Madeline A. Marshall; Mario Nonino; Nor Pirzkal; Aaron Robotham; Michael J. Rutkowski; Russell E. Ryan Jr.; Scott Tompkins; Christopher N. A. Willmer; Haojing Yan; Thomas J. Broadhurst; Cheng Cheng; Jose M. Diego; Patrick Kamieneski; Min Yun

arXiv · 2306.16039

Hidden giants in JWST's PEARLS: An ultra-massive z=4.26 sub-millimeter galaxy that is invisible to HST

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Abstract

We present a multi-wavelength analysis using SMA, JCMT, NOEMA, JWST, HST, and SST of two dusty strongly star-forming galaxies, 850.1 and 850.2, seen through the massive cluster lens A1489. These SMA-located sources both lie at z=4.26 and have bright dust continuum emission, but 850.2 is a UV-detected Lyman-break galaxy, while 850.1 is undetected at <2um, even with deep JWST/NIRCam observations. We investigate their stellar, ISM, and dynamical properties, including a pixel-level SED analysis to derive sub-kpc-resolution stellar-mass and Av maps. We find that 850.1 is one of the most massive and highly obscured, Av~5, galaxies known at z>4 with M*~10^11.8 Mo (likely forming at z>6), and 850.2 is one of the least massive and least obscured, Av~1, members of the z>4 dusty star-forming population. The diversity of these two dust-mass-selected galaxies illustrates the incompleteness of galaxy surveys at z>3-4 based on imaging at <2um, the longest wavelengths feasible from HST or the ground. The resolved mass map of 850.1 shows a compact stellar mass distribution, Re(mass)~1kpc, but its expected evolution to z~1.5 and then z~0 matches both the properties of massive, quiescent galaxies at z~1.5 and ultra-massive early-type galaxies at z~0. We suggest that 850.1 is the central galaxy of a group in which 850.2 is a satellite that will likely merge in the near future. The stellar morphology of 850.1 shows arms and a linear bar feature which we link to the active dynamical environment it resides within.

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Ian Smail, Ugne Dudzeviciute, Mark Gurwell, Giovanni G. Fazio, S. P. Willner, A. M. Swinbank, Vinodiran Arumugam, Jake Summers, Seth H. Cohen, Rolf A. Jansen, Rogier A. Windhorst, Ashish Meena, Adi Zitrin, William C. Keel, Dan Coe, Christopher J. Conselice, Jordan C. J. D'Silva, Simon P. Driver, Brenda Frye, Norman A. Grogin, Anton M. Koekemoer, Madeline A. Marshall, Mario Nonino, Nor Pirzkal, Aaron Robotham, Michael J. Rutkowski, Russell E. Ryan Jr., Scott Tompkins, Christopher N. A. Willmer, Haojing Yan, Thomas J. Broadhurst, Cheng Cheng, Jose M. Diego, Patrick Kamieneski, Min Yun. 2023-06-28. Hidden giants in JWST's PEARLS: An ultra-massive z=4.26 sub-millimeter galaxy that is invisible to HST. https://arxiv.org/abs/2306.16039

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