Project B6

Project leaders: Walch-Gassner, Stefanie (PH1)

In B6 we investigate the formation and evolution of massive star habitats for different environmental conditions typically found across Cosmic Time by means of 3D MHD simulations with our extended multi-physics simulation framework which is based on the adaptive mesh refinement code FLASH. This is done on larger scales (∽1-few kpc) to probe different galactic environments as well as on smaller scales by zooming into the forming molecular clouds where massive star formation is about to take place. On larger scales we inform our simulations from observations of nearby galaxies as well simulations of galaxy evolution. On smaller scales, we aim to deliver knowledge on the mass and energy flowing from large to small scales and feeding pc-scale massive star habitats as studied in project area A. For example, we will be able to answer the questions whether, on any particular scale, the massive star habitats dynamically decouple from the respectively larger scale. We will also be able to address the importance of external (galactic environment such as spiral arm potential or merger, high radiation environment near a Galactic Center etc) vs. internal properties (turbulence, sub-structure, magnetic field strength) for evaluating which conditions promote or hinder massive star formation. Since the many physical processes which shape the multi-phase interstellar medium interact in a non-linear way, this evaluation is non-trivial. By improving our simulation code further to include the radiative transfer of cooling radiation from hot, stellar feedback-driven bubbles, we will add a unique aspect to such simulations of the multi-phase interstellar medium. We expect the latter aspect to be of particular importance for dense and gas- rich environments, where massive stars are preferentially forming. The dynamics of the gas might be completely altered in these environments, where the re-radiated photons are again re-absorbed, boosting the energy footprint of massive star feedback. Over the next twelve years, B6 aims to show whether a universal star formation process is feasible given the variety of galactic environments, and which physical processes are responsible for it after all.

Publications

@article{2025A&A...694A..69H,

title = {Emergence of high-mass stars in complex fiber networks (EMERGE): V. From filaments to spheroids: the origin of the hub-filament systems},

author = {A. Hacar and R. Konietzka and D. Seifried and S. E. Clark and A. Socci and F. Bonanomi and A. Burkert and E. Schisano and J. Kainulainen and R. Smith},

doi = {10.1051/0004-6361/202450779},

year  = {2025},

date = {2025-02-01},

urldate = {2025-02-01},

journal = {A&A},

volume = {694},

pages = {A69},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2025MNRAS.537..482B,

title = {The impact of cosmic-ray heating on the cooling of the low-metallicity interstellar medium},

author = {Vittoria Brugaletta and Stefanie Walch and Thorsten Naab and Philipp Girichidis and Tim-Eric Rathjen and Daniel Seifried and Pierre Colin Nürnberger and Richard Wünsch and Simon C. O. Glover},

doi = {10.1093/mnras/staf039},

year  = {2025},

date = {2025-02-01},

journal = {Monthly Notices of the RAS},

volume = {537},

number = {1},

pages = {482-499},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2024A&A...692A..58E,

title = {The origin and evolution of the [CII] deficit in HII regions and star-forming molecular clouds},

author = {S. Ebagezio and D. Seifried and S. Walch and T. G. Bisbas},

doi = {10.1051/0004-6361/202449682},

year  = {2024},

date = {2024-12-01},

urldate = {2024-12-01},

journal = {A&A},

volume = {692},

pages = {A58},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2024A&A...690A.348C,

title = {JWST MIRI and NIRCam observations of NGC 891 and its circumgalactic medium},

author = {Jérémy Chastenet and Ilse De Looze and Monica Relaño and Daniel A. Dale and Thomas G. Williams and Simone Bianchi and Emmanuel M. Xilouris and Maarten Baes and Alberto D. Bolatto and Martha L. Boyer and Viviana Casasola and Christopher J. R. Clark and Filippo Fraternali and Jacopo Fritz and Frédéric Galliano and Simon C. O. Glover and Karl D. Gordon and Hiroyuki Hirashita and Robert Kennicutt and Kentaro Nagamine and Florian Kirchschlager and Ralf S. Klessen and Eric W. Koch and Rebecca C. Levy and Lewis McCallum and Suzanne C. Madden and Anna F. McLeod and Sharon E. Meidt and Aleksandr V. Mosenkov and Helena M. Richie and Amélie Saintonge and Karin M. Sandstrom and Evan E. Schneider and Evgenia E. Sivkova and J. D. T. Smith and Matthew W. L. Smith and Arjen Wel and Stefanie Walch and Fabian Walter and Kenneth Wood},

doi = {10.1051/0004-6361/202451033},

year  = {2024},

date = {2024-10-01},

urldate = {2024-10-01},

journal = {A&A},

volume = {690},

pages = {A348},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2024MNRAS.532.1262W,

title = {Properties of molecular clumps and cores in colliding magnetized flows},

author = {M. Weis and S. Walch and D. Seifried and S. Ganguly},

doi = {10.1093/mnras/stae1518},

year  = {2024},

date = {2024-08-01},

journal = {Monthly Notices of the RAS},

volume = {532},

number = {2},

pages = {1262-1295},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2024MNRAS.528.3630G,

title = {SILCC-Zoom: the dynamic balance in molecular cloud substructures},

author = {Shashwata Ganguly and S. Walch and S. D. Clarke and D. Seifried},

doi = {10.1093/mnras/stae032},

year  = {2024},

date = {2024-02-01},

urldate = {2024-02-01},

journal = {Monthly Notices of the RAS},

volume = {528},

number = {2},

pages = {3630-3657},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

References

1. Gatto, Walch, Naab, Girichidis, Wünsch, Glover, Klessen, Clark, et al., “The SILCC project – III. Regu- lation of star formation and outflows by stellar winds and supernovae”, MNRAS 466, 1903 (2017).
2. Girichidis, Walch, Naab, Gatto, Wünsch, Glover, Klessen, Clark, et al., “The SILCC (SImulating theLifeCycle of molecular Clouds) project – II. Dynamical evolution of the supernova-driven ISM and thelaunching of outflows”, MNRAS 456, 3432 (2016).
3. Haid, Walch, Seifried, Wünsch, Dinnbier, and Naab, “SILCC-Zoom: The early impact of ionizing radia-tion on forming molecular clouds”, MNRAS 482, 4062 (2019).
4. Haid, Walch, Seifried, Wünsch, Dinnbier, and Naab, “The relative impact of photoionizing radiation andstellar winds on different environments”, MNRAS 478, 4799 (2018).
5. Mackey, Walch, Seifried, Glover, Wünsch, and Aharonian, “Non-equilibrium chemistry and destructionof CO by X-ray flares”, MNRAS 486, 1094 (2019).
6. Seifried, Walch, Girichidis, Naab, Wünsch, Klessen, Glover, Peters, et al., “SILCC-Zoom: the dynamicand chemical evolution of molecular clouds”, MNRAS 472, 4797 (2017).
7. Walch, Girichidis, Naab, Gatto, Glover, Wünsch, Klessen, Clark, et al., “The SILCC (SImulating theLifeCycle of molecular Clouds) project – I. Chemical evolution of the supernova-driven ISM”, MNRAS454, 238 (2015).
8. Walch, Whitworth, Bisbas, Wünsch, and Hubber, “Clumps and triggered star formation in ionizedmolecular clouds”, MNRAS 435, 917 (2013).
9. Wünsch, Walch, Dinnbier, and Whitworth, “Tree-based solvers for adaptive mesh refinement codeFLASH – I: gravity and optical depths”, MNRAS 475, 3393 (2018).
10. Wünsch, Walch, Dinnbier, Seifried, Haid, Klepitko, Whitworth, and Palouš, “Tree-based solvers foradaptive mesh refinement code FLASH – II: radiation transport module TreeRay”, MNRAS 505, 3730 (2021).