Cluster formation and gas kinematics in high mass clouds -Amelia Stutz

Amelia Stutz Universidad de Concepcion Cluster formation and gas kinematics in high mass clouds. By observationally scrutinizing the nearest high mass clouds and protoclusters, we gain new insights into cluster formation physics. The Integral Shaped Filament (ISF) is home to the nearest significant protocluster, the Orion Nebula Cluster (ONC/M42). Based on a high density of observables of both the gas and stars, we previously proposed the “slingshot” mechanism, requiring that the gas ISF oscillate ejecting stars. The B-field morphology (possibly helical) and strength, compared with the gas mass distribution, indicates that magnetic instabilities may be propagating through the cloud driving the oscillations in the ISF. These may be responsible for the slingshot. The gas kinematics exhibit twisting and turning features that may be consistent with rotation and helical structures in the dense gas. We show that the stellar density follows a Plummer profile while the gas follows a cylindrical power law. The stellar contribution to the gravitational field is nearly equal to that of the gas at r=a. At all other radii the field is gas-dominated. The cluster crossing time is ~ 0.5 Myr, nearly identical to the filament oscillation timescale. These results reveal an intimate connection between the stars and the gas, such that tidal effects due to filament oscillations may set the protocluster structure. That is, the gas density regulates the star density in the ONC. Meanwhile, in California cloud, which has the same mass as Orion but is at an earlier evolutionary stage (~1/10th the protostars), we detect rotation in cluster-forming filament L1482. Results in extragalactic systems show that cloud rotation is set by the overall galaxy rotation and not consistent with e.g. cloud-collision models. Combined, these results may indicate that velocity gradients in Milky Way protoclusters are naturally explained by rotation (and helicity), which is established on large scales of galaxy disks and then percolates down to protocluster and possibly even to the tiny scales of protostars.

Horarios: Desde Abril 27, 2021 15:30 hasta Abril 27, 2021 16:30

Publicado por: Patricia Tissera