The ALPINE-ALMA [C II] Survey: kinematic diversity and rotation in massive star-forming galaxies at z 4.4-5.9

November 2021 • 2021MNRAS.507.3540J

Authors • Jones, G. C. • Vergani, D. • Romano, M. • Ginolfi, M. • Fudamoto, Y. • Béthermin, M. • Fujimoto, S. • Lemaux, B. C. • Morselli, L. • Capak, P. • Cassata, P. • Faisst, A. • Le Fèvre, O. • Schaerer, D. • Silverman, J. D. • Yan, Lin • Boquien, M. • Cimatti, A. • Dessauges-Zavadsky, M. • Ibar, E. • Maiolino, R. • Rizzo, F. • Talia, M. • Zamorani, G.

Abstract • While the kinematics of galaxies up to z ~ 3 have been characterized in detail, only a handful of galaxies at high redshift (z > 4) have been examined in such a way. The Atacama Large Millimeter/submillimeter Array (ALMA) Large Program to INvestigate [C II] at Early times (ALPINE) survey observed a statistically significant sample of 118 star-forming main-sequence galaxies at z = 4.4-5.9 in [C II]158 $\mu$m emission, increasing the number of such observations by nearly 10×. A preliminary qualitative classification of these sources revealed a diversity of kinematic types (i.e. rotators, mergers, and dispersion-dominated systems). In this work, we supplement the initial classification by applying quantitative analyses to the ALPINE data: a tilted ring model (TRM) fitting code (3DBAROLO), a morphological classification (Gini-M20), and a set of disc identification criteria. Of the 75 [C II]-detected ALPINE galaxies, 29 are detected at sufficient significance and spatial resolution to allow for TRM fitting and the derivation of morphological and kinematic parameters. These 29 sources constitute a high-mass subset of the ALPINE sample ($M_*\gt 10^{9.5}\, \mathrm{M}_{\odot }$). We robustly classify 14 of these sources (six rotators, five mergers, and three dispersion-dominated systems); the remaining sources showing complex behaviour. By exploring the G-M20 of z > 4 rest-frame far-infrared and [C II] data for the first time, we find that our 1 arcsec ~ 6 kpc resolution data alone are insufficient to separate galaxy types. We compare the rotation curves and dynamical mass profiles of the six ALPINE rotators to the two previously detected z ~ 4-6 unlensed main-sequence rotators, finding high rotational velocities (~50-250 km s-1) and a diversity of rotation curve shapes.


IPAC Authors


Andreas Faisst

Assistant Scientist