Letters of Intent received in 2016

LoI 2018-1920
Focus Meeting: Polarimetric observations to probe magnetic fields from the ISM to stars

Topics

Polarimetric astronomical observations as a tracer of magnetic field topology and intensity across scales and physical environments
Angular momentum problem and magnetic flux problem in star formation
Polarization in the interstellar medium (polarized dust continuum emission, line linear polarization)
Polarization of star forming cores and protostars ( line linear and circular polarization, polarized dust continuum emission)
Polarization of protoplanetary disks and pre main sequence stars (polarized infrared emission, scattered light, spectropolarimetry of forbidden lines)
Polarization of stars (spectropolarimetry, hydrogen lines)

Rationale

In this focus meeting we wish to bring together communities working on all processes involved in star formation, from those
occurring in the diffuse gas to those in the young stars themselves.
The goal is to discuss how polarimetric astronomical observations help each community understand the effect of magnetic fields, from the turbulent ISM to protostars and up to the magnetism of stars.

We plan to address a wide range of topics, a few suggestions as of how we propose to tackle this issue are outlined here:
- Discuss astronomical observations of polarized emission from continuum and spectral lines, exploring the regimes and scales probed by present facilities.
- How to characterize magnetic fields across all scales in the ISM ? Do dust continuum polarization, and polarization from molecular lines trace similar magnetic topologies ?
- What roles for magnetic fields and turbulence in the formation and evolution of filamentary structures in molecular clouds ?
- Observations of magnetic fields in young stellar objects : is protostellar accretion regulated by magnetic effects ? Are protostellar jets magnetized ? Is magnetic braking dynamically important for the formation of solar-type stars ?
- Are protoplanetary disks and pre main sequence stars magnetized ? Do we have clues for magnetic disk-star interaction ?
- Polarimetric observations of stars: do we have clues to address the magnetic flux problem (mechanisms for removing magnetic flux during star formation so as to reconcile the weak magnetic fluxes observed in stars with the much stronger magnetic fields observed in star-forming cores) ?
- Identify novel techniques (instrumental and observational) and their relevance to cornerstone questions identified across communities

Our working group presently includes JM Girart (ICE, Spain), C. Hull (CfA Harvard, USA), M. Houde (University of Western Ontario, Canada), Q. Zhang (CfA Harvard, USA), H. Wiesemeyer (MPIfR, Germany), A. Bracco (CEA/AIM, France) and E. Falgarone (ENS, France).
We are inviting members involved in the above mentioned topics to contact us with suggestions to improve this program proposal.