TY - JOUR
T1 - Kiloparsec view of a typical star-forming galaxy when the Universe was ∼ Gyr old
T2 - II. Regular rotating disk and evidence for baryon dominance on galactic scales
AU - Herrera-Camus, R.
AU - Förster Schreiber, N. M.
AU - Price, S. H.
AU - Ubler, H.
AU - Bolatto, A. D.
AU - Davies, R. L.
AU - Fisher, D.
AU - Genzel, R.
AU - Lutz, D.
AU - Naab, T.
AU - Nestor, A.
AU - Shimizu, T.
AU - Sternberg, A.
AU - Tacconi, L.
AU - Tadaki, K.
N1 - Publisher Copyright: ©
PY - 2022/9/1
Y1 - 2022/9/1
N2 - We present a kinematic analysis of the main-sequence galaxy HZ4 at z = 5.5. Our study is based on deep, spatially resolved observations of the [C II] 158 μm transition obtained with the Atacama Large Millimeter/Submillimeter Array (ALMA). From the combined analysis of the disk morphology, the 2D velocity structure, and forward modeling of the 1D velocity and velocity dispersion profiles, we conclude that HZ4 has a regular rotating disk in place. The intrinsic velocity dispersion in HZ4 is high (0=65.83.3+2.9 km s1), and the ratio between the rotational velocity and the intrinsic velocity dispersion is Vrot/0 = 2.2. These values are consistent with the expectations from the trends of increasing 0 and decreasing Vrot/0 as a function of the redshift observed in main-sequence galaxies up to z 4. Galaxy evolution models suggest that the high level of turbulence observed in HZ4 can only be achieved if, in addition to stellar feedback, there is radial transport of gas within the disk. Finally, we find that HZ4 is baryon-dominated on galactic scales (2-Re), with a dark-matter fraction at one effective radius of fDM(Re)=0.410.22+0.25. This value is comparable to the dark-matter fractions found in lower redshift galaxies that could be the descendants of HZ4: massive (M1011M), star-forming galaxies at z 2, and passive, early-type galaxies at z 0.
AB - We present a kinematic analysis of the main-sequence galaxy HZ4 at z = 5.5. Our study is based on deep, spatially resolved observations of the [C II] 158 μm transition obtained with the Atacama Large Millimeter/Submillimeter Array (ALMA). From the combined analysis of the disk morphology, the 2D velocity structure, and forward modeling of the 1D velocity and velocity dispersion profiles, we conclude that HZ4 has a regular rotating disk in place. The intrinsic velocity dispersion in HZ4 is high (0=65.83.3+2.9 km s1), and the ratio between the rotational velocity and the intrinsic velocity dispersion is Vrot/0 = 2.2. These values are consistent with the expectations from the trends of increasing 0 and decreasing Vrot/0 as a function of the redshift observed in main-sequence galaxies up to z 4. Galaxy evolution models suggest that the high level of turbulence observed in HZ4 can only be achieved if, in addition to stellar feedback, there is radial transport of gas within the disk. Finally, we find that HZ4 is baryon-dominated on galactic scales (2-Re), with a dark-matter fraction at one effective radius of fDM(Re)=0.410.22+0.25. This value is comparable to the dark-matter fractions found in lower redshift galaxies that could be the descendants of HZ4: massive (M1011M), star-forming galaxies at z 2, and passive, early-type galaxies at z 0.
KW - Galaxies: ISM
KW - Galaxies: high-redshift
KW - Galaxies: kinematics and dynamics
KW - Galaxies: structure
UR - http://www.scopus.com/inward/record.url?scp=85140248160&partnerID=8YFLogxK
U2 - https://doi.org/10.1051/0004-6361/202142562
DO - https://doi.org/10.1051/0004-6361/202142562
M3 - مقالة
SN - 0004-6361
VL - 665
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - L8
ER -