Project B4

Project leaders: Mao, Sui Ann (MPIfR); Seifried, Daniel (PH1); Menten, Karl (MPIfR)

Magnetic fields (B-fields) play an important role in the process of (massive) star formation, from the scale of whole galaxies down to those of molecular clouds and cores (e.g. Crutcher, ARA&A 50, 29, 2012; Beck et al., Galaxies 8, 4, 2019). Their study, however, is challenging from both the observational and theoretical side. First, magnetic fields can be can be observed only indirectly via polarised radiation, which is generally weak. In addition, the emission is intrinsically convolved with the density of the underlying tracer, either atoms, molecules or dust. Second, the study of magnetic fields requires specifically designed magnetohydrodynamics (MHD) codes to model them. Here we aim to combine the effort from observations and simulations to investigate the role of B-fields in star formation, to assess the accuracy of observational techniques, and to gather further insights on underlying (microscopic) mechanisms, namely synchrotron emission, dust alignment, and the influence of radiation from massive stars. In B4 we plan to approach this topic from the observational and theoretical side by means of three different work packages, B4.1, B4.2 and B4.2. In particular we will address the following questions:

• Can multi-wavelength observations help to disentangle the B-field structure in the ISM and reliably determine its strength both in the plane of sky and along the line of sight?
• Do B-fields have a stabilising effect on molecular clouds and their embedded filaments and thus potentially delay the formation of massive stars?
• Can polarisation observations reveal insights into dust properties like geometrical shape and composition?
• What can we learn from radio polarisation observations about the interplay and relative importance of turbulence, gravity and B-fields, as well as the chemical state of the ISM?

Publications

@article{2024A&A...688A.194K,

title = {HYACINTH: HYdrogen And Carbon chemistry in the INTerstellar medium in Hydro simulations},

author = {Prachi Khatri and Cristiano Porciani and Emilio Romano-Díaz and Daniel Seifried and Alexander Schäbe},

doi = {10.1051/0004-6361/202449640},

year  = {2024},

date = {2024-08-01},

journal = {A&A},

volume = {688},

pages = {A194},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2024MNRAS.528.6370F,

title = {On the evolution of the observed mass-to-length relationship for star-forming filaments},

author = {Jiancheng Feng and Rowan J. Smith and Alvaro Hacar and Susan E. Clark and Daniel Seifried},

doi = {10.1093/mnras/stae407},

year  = {2024},

date = {2024-03-01},

urldate = {2024-03-01},

journal = {Monthly Notices of the RAS},

volume = {528},

number = {4},

pages = {6370-6387},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

References:

1. Brunthaler, Menten, Dzib, Cotton, Wyrowski, Dokara, Gong, Medina, et al., “A global view on star formation: The GLOSTAR Galactic plane survey. I. Overview and first results for the Galactic longitude range 28°< l < 36°”, A&A 651, A85 (2021).
2. Kierdorf, Mao, Beck, Basu, Fletcher, Horellou, Tabatabaei, Ott, et al., “The magnetized disk-halo tran- sition region of M 51”, A&A 642, A118 (2020).
3. Koley, Roy, Menten, Jacob, Pillai, and Rugel, “The magnetic field in the dense photodissociation region of DR 21”, MNRAS 501, 4825 (2021).
4. Mao, Zweibel, Fletcher, Ott, and Tabatabaei, “Properties of the Magneto-ionic Medium in the Halo of M51 Revealed by Wide-band Polarimetry”, ApJ 800, 92 (2015).
5. Pillai, Clemens, Reissl, Myers, Kauffmann, 30 co-authors including, Menten, and Seifried, “Magnetized filamentary gas flows feeding the young embedded cluster in Serpens South”, Nature Astronomy 4, 1195 (2020).
6. Reissl, Wolf, and Seifried, “Tracing the ISM magnetic field morphology: the potential of multi-wavelength polarization measurements”, A&A 566, A65 (2014).
7. Reissl, Stutz, Klessen, Seifried, and Walch, “Magnetic fields in star-forming systems – II: Examining dust polarization, the Zeeman effect, and the Faraday rotation measure as magnetic field tracers”, MNRAS 500, 153 (2021).
8. Seifried, Walch, Girichidis, Naab, Wünsch, Klessen, Glover, Peters, et al., “SILCC-Zoom: the dynamic and chemical evolution of molecular clouds”, MNRAS 472, 4797 (2017).
9. Seifried, Walch, Reissl, and Ibáñez-Mejía, “SILCC-Zoom: Polarization and depolarization in molecular clouds”, MNRAS 482, 2697 (2019).
10. Seifried, Walch, Weis, Reissl, Soler, Klessen, and Joshi, “From parallel to perpendicular – On the orientation of magnetic fields in molecular clouds”, MNRAS 497, 4196 (2020).