Astronomy Colloquium for 2019-02-06


Series: Astronomy Colloquium
Date: Wednesday 06-Feb-2019
Time: 16:05-17:00 (4:05-5:00 pm)
Location: ATL 2400
Speaker: Dr. Tess Jaffe (GSFC/UMD)
Title: IMAGINE’ing Galactic Magnetic Fields

The Galactic magnetic field (GMF) plays an important role in a variety of astrophysical processes but is not well understood. Magnetic fields in the interstellar medium are difficult to study directly but affect phenomena as diverse as: the propagation of cosmic rays; the formation of stars; the morphology of supernova remnants; the deflections in the arrival directions of extragalactic ultra-high energy cosmic rays (UHECRs); the cosmic microwave background (CMB). I will review how data across the electromagnetic spectrum are giving us new and different views of the fields (for example, polarized dust emission from Planck, or anisotropies in the arrival directions of UHECRs seen with Auger or IceCube) and how these data are difficult to interpret because of the complexity of the different contexts and the degeneracies in the parameter space. The Interstellar MAGnetic field INference Engine (IMAGINE) is our new framework for combining all available observables as well as theoretical knowledge into a statistically rigorous Bayesian analysis. This will allow us to incorporate *all* available information to break some of these degeneracies as well as to explicitly quantify how well different models reproduce the same observables with the Bayesian evidence. I will summarize the project, the infrastructure we have made publicly available, and our plans to build more realistic GMF models based on magneto-hydrodynamical dynamo equations and to attempt both parametric and non-parametric reconstructions of the GMF.


Colloquia are usually preceded by espresso and ice cream at 1:45 pm outside room PSC 1150 and are followed by an informal reception at 5:15 pm in that room. Anyone interested in talking with the speaker, or being added to the colloquium announcement email list, should contact the colloquium organizer. Lunch will normally be reserved for the speaker to talk to graduate students. Anyone asking a question during a talk is asked to raise their hand and be acknowledged before speaking.

Colloquium Organizer: Prof. Richard Mushotzy

SPECIAL ACCOMMODATIONS:

Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.

DIRECTIONS, PARKING, AND OTHER INFORMATION FOR VISITORS

Directions and information about parking can be found here.

This page was automatically generated on: 26-Apr-2019.