Mapping Galaxy Scale Magnetic Fields

Abstract:
If the Milky Way were viewed externally and edge-on, how would the magnetic (B) field threading the cold interstellar medium (ISM) appear? Models of the alpha-omega-dynamo process in disk galaxies predict that the B-field should be predominantly parallel to the plane of the disk. The Polarization of Edge-on Galaxy Sample (PEGS) addresses this question by mapping the polarization of near-infrared (NIR) light from 12 nearby, edge-on galaxies. The new, arcsecond resolution maps produced as part of this study will, for the first time, reveal the large scale B-field configuration across the full disk of these galaxies. Early analysis of these polarization maps indicate that the B-field is not always parallel to the disk, and its orientation sometimes varies along both the major and minor axes of the galaxy.

Talk Host:  Joey Neilsen

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Fast and Furious: Young Supernovae and Their Progenitors

Abstract:
Observations of supernovae within a few days of explosion provide unique constraints to the nature of their progenitors. Since 2013, as a part of my thesis, I used the intermediate Palomar Transient Factory (iPTF) to systematically study extraordinarily young supernovae. I will first provide an overview of iPTF survey design, summarize the fast turnaround discovery pipeline and then outline the rapid response follow-up. The highlights of my work are as follows: 1) We observed a strong declining UV emission from a low-velocity Type Ia supernova which is consistent with the expected emission from a supernova slamming into a companion star. Our observation evidently suggests that some Type Ia supernovae arise from the so-called “single degenerate” channel. 2) We identified the first progenitor candidate of a Type Ib supernova in the pre-explosion HST images. Our multi-wavelength observations of this young Type Ib supernova constrain its progenitor to be smaller than several solar radii and with strong mass loss. I will end my talk with prospets for this field with the upcoming Zwicky Transient Facility and adapting the rapid-response system to searching for electromagnetic counterparts of advanced LIGO events.

Talk Host: Niels Warburton

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