학술논문
Galaxies Going Bananas: Inferring the 3D Geometry of High-Redshift Galaxies with JWST-CEERS
Document Type
Working Paper
Author
Pandya, Viraj; Zhang, Haowen; Huertas-Company, Marc; Iyer, Kartheik G.; McGrath, Elizabeth; Barro, Guillermo; Finkelstein, Steven L.; Kuemmel, Martin; Hartley, William G.; Ferguson, Henry C.; Kartaltepe, Jeyhan S.; Primack, Joel; Dekel, Avishai; Faber, Sandra M.; Koo, David C.; Bryan, Greg L.; Somerville, Rachel S.; Amorin, Ricardo O.; Haro, Pablo Arrabal; Bagley, Micaela B.; Bell, Eric F.; Bertin, Emmanuel; Costantin, Luca; Dave, Romeel; Dickinson, Mark; Feldmann, Robert; Fontana, Adriano; Gavazzi, Raphael; Giavalisco, Mauro; Grazian, Andrea; Grogin, Norman A.; Guo, Yuchen; Hahn, ChangHoon; Holwerda, Benne W.; Kewley, Lisa J.; Kirkpatrick, Allison; Koekemoer, Anton M.; Lotz, Jennifer M.; Lucas, Ray A.; Pentericci, Laura; Perez-Gonzalez, Pablo G.; Pirzkal, Nor; Kocevski, Dale D.; Papovich, Casey; Ravindranath, Swara; Rose, Caitlin; Schefer, Marc; Simons, Raymond C.; Straughn, Amber N.; Tacchella, Sandro; Trump, Jonathan R.; de la Vega, Alexander; Wilkins, Stephen M.; Wuyts, Stijn; Yang, Guang; Yung, L. Y. Aaron
Source
Subject
Language
Abstract
The 3D geometry of high-redshift galaxies remains poorly understood. We build a differentiable Bayesian model and use Hamiltonian Monte Carlo to efficiently and robustly infer the 3D shapes of star-forming galaxies in JWST-CEERS observations with $\log M_*/M_{\odot}=9.0-10.5$ at $z=0.5-8.0$. We reproduce previous results from HST-CANDELS in a fraction of the computing time and constrain the mean ellipticity, triaxiality, size and covariances with samples as small as $\sim50$ galaxies. We find high 3D ellipticities for all mass-redshift bins suggesting oblate (disky) or prolate (elongated) geometries. We break that degeneracy by constraining the mean triaxiality to be $\sim1$ for $\log M_*/M_{\odot}=9.0-9.5$ dwarfs at $z>1$ (favoring the prolate scenario), with significantly lower triaxialities for higher masses and lower redshifts indicating the emergence of disks. The prolate population traces out a ``banana'' in the projected $b/a-\log a$ diagram with an excess of low $b/a$, large $\log a$ galaxies. The dwarf prolate fraction rises from $\sim25\%$ at $z=0.5-1.0$ to $\sim50-80\%$ at $z=3-8$. If these are disks, they cannot be axisymmetric but instead must be unusually oval (triaxial) unlike local circular disks. We simultaneously constrain the 3D size-mass relation and its dependence on 3D geometry. High-probability prolate and oblate candidates show remarkably similar S\'ersic indices ($n\sim1$), non-parametric morphological properties and specific star formation rates. Both tend to be visually classified as disks or irregular but edge-on oblate candidates show more dust attenuation. We discuss selection effects, follow-up prospects and theoretical implications.
Comment: Accepted version to appear in ApJ, main body is 36 pages of which ~half are full-page figures
Comment: Accepted version to appear in ApJ, main body is 36 pages of which ~half are full-page figures