High resolution spectral imaging of CO(7–6), [CI](2–1), and continuum of three high-z lensed dusty star-forming galaxies using ALMA

• Published in: Astronomy & Astrophysics
• Main Authors: Gururajan, G., Béthermin, M., Theulé, P., Spilker, J. S., Aravena, M., Archipley, M. A., Chapman, S. C., de Breuck, C., Gonzalez, A., Hayward, C. C., Hezaveh, Y., Hill, R., Jarugula, S., Litke, K. C., Malkan, M., Marrone, D. P., Narayanan, D., Phadke, K. A., Reuter, C., Vieira, J. D., Vizgan, D., Weiß, A.
• Other Authors: Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS), University of Texas at Austin Austin, Universidad Diego Portales Santiago - Chili (UDP), University of Illinois at Urbana-Champaign Urbana (UIUC), University of Illinois System, University of British Columbia (UBC), Dalhousie University Halifax, University of Florida Gainesville (UF), Flatiron Institute, Simons Foundation, University of Arizona, University of California Los Angeles (UCLA), University of California (UC), Danmarks Tekniske Universitet = Technical University of Denmark (DTU), Max-Planck-Institut für Radioastronomie (MPIFR)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: galaxies: high-redshift; galaxies: evolution; galaxies: ISM; galaxies: kinematics and dynamics; galaxies: star formation; submillimeter: galaxies; [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]; Milky Way; South Pole; South pole
• Online Access: https://hal.science/hal-03713611; https://hal.science/hal-03713611/document; https://hal.science/hal-03713611/file/aa42172-21.pdf; https://doi.org/10.1051/0004-6361/202142172

International audience High-redshift dusty star-forming galaxies with very high star formation rates (500−3000 M⊙ yr−1) are key to understanding the formation of the most extreme galaxies in the early Universe. Characterising the gas reservoir of these systems can reveal the driving factor behind the high star formation. Using molecular gas tracers such as, high-J CO lines, neutral carbon lines, and the dust continuum, we can estimate the gas density and radiation field intensity in their interstellar media. In this paper, we present high resolution (∼0.4″) observations of CO(7−6), [CI](2−1), and dust continuum of three lensed galaxies from the South pole telescope – sub-millimetre galaxies (SPT-SMG) sample at z ∼ 3 with the Atacama Large Millimetre/submillimetre Array. Our sources have high intrinsic star formation rates (> 850 M⊙ yr−1) and rather short depletion timescales (< 100 Myr). Based on the L[CI](2−1)/LCO(7 − 6) and L[CI](2−1)/LIR ratios, our galaxy sample has similar radiation field intensities and gas densities compared to other submillimetre galaxies. We performed visibility-based lens modelling on these objects to reconstruct the kinematics in the source plane. We find that the cold gas masses of the sources are compatible with simple dynamical mass estimates using ULIRG-like values of the CO-H2 conversion factor αCO, but not Milky Way-like values. We find diverse source kinematics in our sample: SPT0103−45 and SPT2147−50 are likely rotating disks, while SPT2357−51 is possibly a major merger. The analysis presented in the paper could be extended to a larger sample to determine better statistics of morphologies and interstellar medium properties of high-z dusty star-forming galaxies.