分类： 天文学 >> 天文学 提交时间： 2023-02-19
Harley Katz
Shenghua Liu
Taysun Kimm
Martin P. Rey
Eric P. Andersson
Alex J. Cameron
Francisco Rodriguez-Montero
Oscar Agertz
Julien Devriendt
Adrianne Slyz
摘要： We introduce the PRISM interstellar medium (ISM) model for thermochemistry and its implementation in the RAMSES-RTZ code. The model includes a non-equilibrium primordial, metal, and molecular chemistry network for 115 species coupled to on-the-fly multifrequency radiation transport. PRISM accurately accounts for the dominant ISM cooling and heating processes in the low-density regime (i.e. $\rho<10^5\ {\rm cm^{-3}}$), including photoheating, photoelectric heating, H$_2$ heating/cooling, cosmic-ray heating, H/He cooling, metal-line cooling, CO cooling, and dust cooling (recombination and gas-grain collisions). We validate the model by comparing 1D equilibrium simulations across six dex in metallicity to existing 1D ISM models in the literature. We apply PRISM to high-resolution (4.5 pc) isolated dwarf galaxy simulations that include state-of-the-art models for star formation and stellar feedback to take an inventory of which cooling and heating processes dominate each different gas phase of a galaxy and to understand the importance of non-equilibrium effects. We show that most of the ISM gas is either close to thermal equilibrium or exhibits a slight cooling instability, while from a chemical perspective, the non-equilibrium electron fraction is often more than three times higher or lower than the equilibrium value, which impacts cooling, heating, and observable emission lines. Electron enhancements are attributed to recombination lags while deficits are shown to be due to rapid cosmic-ray heating. The PRISM model and its coupling to RAMSES-RTZ is applicable to a wide variety of astrophysical scenarios, from cosmological simulations to isolated giant molecular clouds, and is particularly useful for understanding how changes to ISM physics impact observable quantities such as metallic emission lines.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Sam Geen
Poojan Agrawal
Paul A. Crowther
B. W. Keller
Alex de Koter
Zsolt Keszthelyi
Freeke van de Voort
Ahmad A. Ali
Frank Backs
Lars Bonne
Vittoria Brugaletta
Annelotte Derkink
Sylvia Ekström
Yvonne A. Fichtner
Luca Grassitelli
Ylva Götberg
Erin R. Higgins
Eva Laplace
Kong You Liow
Marta Lorenzo
摘要： Stars strongly impact their environment, and shape structures on all scales throughout the universe, in a process known as ``feedback''. Due to the complexity of both stellar evolution and the physics of larger astrophysical structures, there remain many unanswered questions about how feedback operates, and what we can learn about stars by studying their imprint on the wider universe. In this white paper, we summarize discussions from the Lorentz Center meeting `Bringing Stellar Evolution and Feedback Together' in April 2022, and identify key areas where further dialogue can bring about radical changes in how we view the relationship between stars and the universe they live in.
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