Turbulent Gas in Lensed Planck-selected Starbursts at redshifts 1-3.5

• Published in: arXiv.org 2020-10
• Main Authors: Harrington, Kevin C, Weiss, Axel, Yun, Min S, Magnelli, Benjamin, Sharon, C E, Leung, T K D, Vishwas, A, Wang, Q D, Jimenez-Andrade, E F, Frayer, D T, Liu, D, Garcia, P, Romano-Diaz, E, Frye, B L, Jarugula, S, Badescu, T, Berman, D, Dannerbauer, H, Diaz-Sanchez, A, Grassitelli, L, Kamieneski, P, Kim, W J, Kirkpatrick, A, Lowenthal, J D, Messias, H, Puschnig, J, Stacey, G J, Torne, P, Bertoldi, F
• Format: Article
• Language: English
• Subjects: Atomic structure; Carbon monoxide; Continuum radiation; Density distribution; Deposition; Dust; Galaxy distribution; Gas density; Gas heating; Luminosity; Molecular gases; Radiative transfer; Red shift; Star formation; Turbulence
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2010.16231

Dusty star-forming galaxies at high redshift (1 < z < 3) represent the most intense star-forming regions in the Universe. Key aspects to these processes are the gas heating and cooling mechanisms. Although it is well known that these galaxies are gas-rich, little is known about the gas excitation conditions. Here we examine these processes in a sample of 24 strongly lensed star-forming galaxies identified by the \textit{Planck} satellite (LPs) at z ~ 1.1 - 3.5. We analyze 162 CO rotational transitions (ranging from Jupper = 1 - 12) and 37 atomic carbon fine-structure lines ([CI]) in order to characterize the physical conditions of the gas in sample of LPs. We simultaneously fit the CO and [CI] lines, and the dust continuum emission, using two different non-LTE, radiative transfer models. The first model represents a two component gas density, while the second assumes a turbulence driven log-normal gas density distribution. These LPs are among the most gas-rich, infrared (IR) luminous galaxies ever observed (\(\mu_{\rm L}\)L\(_{\rm IR(8-1000\mu m) } \sim 10^{13-14.6} \)\Lsun; \(< \mu_{\rm L}\)M\(_{\rm ISM}> = 2.7 \pm 1.2 \times 10^{12}\) \Msun, with \(\mu_{\rm L} \sim 10-30\) the average lens magnification factor). Our results suggest that the turbulent ISM present in the LPs can be well-characterized by a high turbulent velocity dispersion (\( \sim 100 \) \kms) and gas kinetic temperature to dust temperature ratios \( \sim 2.5\), sustained on scales larger than a few kpc. We speculate that the average surface density of the molecular gas mass and IR luminosity \(\Sigma_{\rm M_{\rm ISM}}\) \(\sim 10^{3 - 4}\) \Msun pc\(^{-2}\) and \(\Sigma_{\rm L_{\rm IR}}\) \(\sim 10^{11 - 12}\) \Lsun kpc\(^{-2}\), arise from both stellar mechanical feedback and a steady momentum injection from the accretion of intergalactic gas.