The "Cosmic Seagull": A Highly Magnified Disk-like Galaxy at z ≃ 2.8 behind the Bullet Cluster
Journal article, 2018
We present Atacama Large Millimeter/submillimeter Array measurements of the "Cosmic Seagull," a strongly magnified galaxy at z = 2.7779 behind the Bullet Cluster. We report CO(3-2) and continuum 344 μm (rest-frame) data at one of the highest differential magnifications ever recorded at submillimeter wavelengths (μ up to ∼50), facilitating a characterization of the kinematics of a rotational curve in great detail (at ∼620 pc resolution in the source plane). We find no evidence for a decreasing rotation curve, from which we derive a dynamical mass of (6.3 ± 0.7) × 1010Mowithin r = 2.6 ± 0.1 kpc. The discovery of a third, unpredicted, image provides key information for a future improvement of the lensing modeling of the Bullet Cluster and allows a measure of the stellar mass, , unaffected by strong differential magnification. The baryonic mass is expected to be dominated by the molecular gas content (fgas≤ 80 ± 20%) based on an mass estimated from the difference between dynamical and stellar masses. The star formation rate (SFR) is estimated via the spectral energy distribution (SFR = 190 ± 10 Moyr-1), implying a molecular gas depletion time of 0.25 ± 0.08 Gyr.
galaxies: ISM
galaxies: clusters: individual (1ES0657-558)
galaxies: evolution
gravitational lensing: strong
submillimeter: galaxies
Author
V. Motta
University of Valparaíso
E. Ibar
University of Valparaíso
T. Verdugo
Universidad Nacional Autónoma de México
J. Molina
Universidad de Chile
T. M. Hughes
Chinese Academy of Sciences
University of Science and Technology of China
University of Valparaíso
M. Birkinshaw
University of Bristol
O. López-Cruz
National Institute of Astrophysics, Optics and Electronics
John H Black
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
D. Gunawan
University of Valparaíso
Cathy Horellou
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
J. Magana
University of Valparaíso
Astrophysical Journal Letters
2041-8205 (ISSN) 2041-8213 (eISSN)
Vol. 863 2 L16Subject Categories
Subatomic Physics
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Roots
Basic sciences
DOI
10.3847/2041-8213/aad6de