The formation of stars is one of the most important events that shape the physical, chemical, and dynamical properties of their host galaxy. Stars form in the densest parts of molecular clouds (interstellar clouds of molecules and dust). Due to the high extinction of optical light by dust grains mixed with the gas, the birth of stars must be studied at infrared and longer wavelengths (in the millimeter and centimeter domain) that can penetrate clouds. These molecular clouds are highly inhomogeneous: they are shaped in filamentary structures that contain chains of dense cores that will eventually undergo collapse due to gravity to form protostars. Molecular cloud fragmentation leading to the formation of dense cores is controlled by a complex interaction of gravity, turbulence, magnetic fields, and stellar feedback.
The mechanism that regulates the evolution of molecular clouds and the star formation process is still under debate. There are two main proposed scenarios to explain the formation of stars: 1) the quasi-static star formation scenario, where magnetic fields and turbulence control the dynamics and evolution of molecular clouds through a slow contraction of gas and dust; 2) the dynamic star formation scenario, where turbulence is the main agent controlling both the evolution of molecular clouds and the formation of stars through a fast contraction of gas and dust. It is within this context that the study of the properties of magnetic fields and their influence on the dynamics of molecular clouds is a key issue on the star formation research field.
Observationally, in the last few years it has been found that the magnetic field plays an important role in the formation of stars acting as a support against gravitational collapse. Magnetic fields are indeed present on nearly all physical scales in our Galaxy: galactic, molecular core, and protoplanetry disk scales, from kpc to few hundred of astronomical units. To characterize the role of magnetic fields in shaping the dynamics of star-forming gas structures requires a multi-wavelength polarimetric approach: while the optical and near-infrared observations can trace the diffuse parts of molecular clouds, the millimeter and submillimeter regime probe the magnetic field at dense cores and protoplanetary disk scales.The cutting-edge of radio interferometers available today at (sub)millimeter wavelengths (e.g., ALMA, JVLA, SMA, and NOEMA) that provides high-fidelity and high-sensitivity images, make now possible to investigate with unprecedented detail the protostellar embryos, unveiling the physical processes that give rise to the formation of stars and planetary systems.
The research activity of the group “Interstellar Medium: star and planet formation” is focused in the early stages of the star and planet formation process, with special emphasis on the role of magnetic field at different scales.
In particular, we aim at investigating:
- Cortes, P. C., Girart, J. M., Hull, C. L. H., et al., "Interferometric
Mapping of Magnetic Fields: The ALMA View of the Massive Star-forming Clump W43-MM1", 2016, The Astrophysical Journal Letters, 825, L15
- Carrasco-González, C., Torrelles, J. M., Cantó, J., et al.,
"Observing the onset of outflow collimation in a massive protostar", 2015, Science, 348, 114
- Busquet, G., Zhang, Q., Palau, A., et al., "Unveiling a Network of Parallel Filaments in the Infrared Dark Cloud G14.225-0.506", 2013, The Astrophysical Journal Letters, 764, L26
- Torrelles, J. M., Patel, N. A., Curiel, S., et al., "A wide-angle outflow with the simultaneous presence of a high-velocity jet in the high-mass Cepheus A HW2 system", 2011, Monthly Notices of the Royal Astronomical Society, 410, 627
- Girart, J. M., Beltrán, M. T., Zhang, Q., Rao, R., & Estalella, R., "Magnetic Fields in the Formation of Massive Stars", 2009, Science, 324, 1408
Josep Miquel Girart, José María Torrelles, Gemma Busquet, Carmen Juárez, Nacho Añez