Observations of neutral carbon in 29 high-z lensed dusty star-forming galaxies and the comparison of gas mass tracers

• Published in: Astronomy & Astrophysics
• Main Authors: Gururajan, G., Bethermin, M., Sulzenauer, N., Theulé, P., Spilker, J. S., Aravena, M., Chapman, S. C., Gonzalez, A., Greve, T. R., Narayanan, D., Reuter, C., Vieira, J. 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), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: galaxies: high-redshift; galaxies: evolution; galaxies: ISM; galaxies: star formation; submillimeter: galaxies; Astrophysics - Astrophysics of Galaxies; [SDU]Sciences of the Universe [physics]; South Pole; South pole
• Online Access: https://insu.hal.science/insu-04198350; https://insu.hal.science/insu-04198350/document; https://insu.hal.science/insu-04198350/file/aa46449-23.pdf; https://doi.org/10.1051/0004-6361/202346449

International audience Context. The nature and evolution of high-redshift dusty star-forming galaxies (high-z DSFGs) remain open questions. Their massive gas reservoirs play an important role in driving the intense star formation rates hosted in these galaxies. Aims: Our aim is to estimate the molecular gas content of high-z DSFGs by using various gas mass tracers, such as the [CI], CO, [CII] emission lines and the dust content. These tracers need to be well calibrated as they are all limited by uncertainties on factors such as α CO , X CI , α [CII] , and δ GDR , thereby affecting the accurate determination of the gas mass. The main goal of our work is to check the consistency between the gas mass tracers and to cross-calibrate the uncertain factors. Methods: We observed the two [CI] line transitions for 29 South Pole telescope Submillimeter Galaxies (SPT-SMGs) with the Atacama Large Millimeter/submillimeter Array-Atacama Compact Array (ALMA-ACA). Additionally, we also present new Atacama Pathfinder EXperiment (APEX) observations of [CII] line for nine of these galaxies. We combined our observations with the rich ancillary data of low- and mid-J CO lines, ancillary [CII] line, and dust mass estimations for these galaxies. Results: We find a nearly linear relation between the infrared luminosity and [CI] luminosity if we fit the starbursts and main-sequence galaxies separately. We measure a median [CI]-derived excitation temperature of 34.5 ± 2.1 K. We probed the properties of the interstellar medium (ISM), such as density and radiation field intensity, using [CI] to mid- or high-J CO lines and the [CI]-to-infrared luminosity ratio, and find similar values to the SMG populations in the literature. Finally, the gas masses estimated from [CI], CO, dust, and [CII] do not exhibit any significant trend with the infrared luminosity or the dust temperature. We provide the various cross-calibrations between these tracers. Conclusions: Our study confirms that [CI] is a suitable tracer of the molecular gas content, and ...