ABI CHOWN

About


AC_photo

I am a third year PhD student working in the Astrophysics Group at the University of Bath, UK.
My PhD supervisors are Dr. Victoria Scowcroft and Dr. Stijn Wuyts.


My research focuses on the Magellanic Clouds: two dwarf galaxies in the Local Group. Using variable stars, namely Classical Cepheids and RR Lyraes, I am building highly-precise 3D maps of the Magellanic Clouds. Due to the well-defined Period-Luminosity and Period-Luminosity-Metallicity relations for Cepheids and RR Lyraes, respectively, these stars serve as robust distance indicators. Hence, they can be used to construct 3D maps of nearby galaxies, and the intrinsic 3D geometric structure of these systems can be traced by these stellar populations.

Link to my profile on the University of Bath Research Portal

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Research


PhD research

LMC

My research focuses on the Magellanic Clouds: two dwarf galaxies in the Local Group. Using variable stars, namely Classical Cepheids and RR Lyraes, I am building highly-precise 3D maps of the Magellanic Clouds. Due to the well-defined Period-Luminosity (PL) and Period-Luminosity-Metallicity (PLZ) relations for Cepheids and RR Lyraes, respectively, these stars serve as robust distance indicators. Hence, they can be used to construct 3D maps of nearby galaxies, and the intrinsic 3D geometric structure of these systems can be traced by these stellar populations.

I work with mid-infrared data from the Spitzer Space Telescope. Working at these longer wavelengths has a number of advantages for variable star work: in the mid-infrared, the dispersion of the PL relation is reduced, there is much less interstellar extinction, and the amplitudes of the light curves are smaller which allows for a more precise determination of mean magnitudes.

I work with two datasets: the first being fully-sampled Cepheid light curve data from the Carnegie Hubble Program (CHP) and the second being the SAGE legacy survey, which performed a uniform survey of the Magellanic Clouds. The CHP dataset consists of 85 LMC and 90 SMC Cepheids, which are used as our calibrating sample. This data is used to create template light curves, which are then applied to the sparser, non-uniformly sampled SAGE data. We will obtain mean magnitudes for all known fundamental-mode Classical Cepheids in the Magellanic System and construct our 3D maps.

LMC Image Credit: Primoz Cigler

Talks & Posters

Masters research

Comparison of project assignments from our SPA code with those obtained from the course organiser

A simulated annealing approach to the Student-Project Allocation (SPA) problem

Abigail H. Chown, Christopher J. Cook, Nigel B. Wilding
American Journal of Physics 86, 701 (2018); https://doi.org/10.1119/1.5045331

We describe a solution to the student-project allocation problem using simulated annealing. The problem involves assigning students to projects, where each student has ranked a fixed number of projects in order of preference. Each project is offered by a specific supervisor (or supervisors), and the goal is to find an optimal matching of students to projects taking into account the students' preferences, the constraint that only one student can be assigned to a given project, and the constraint that supervisors have a maximum workload.

We show that when applied to a real dataset from a university physics department, simulated annealing allows the rapid determination of high quality solutions to this allocation problem. The quality of the solution is quantified by a satisfaction metric derived from empirical student survey data. Our approach provides high quality allocations in a matter of minutes that are as good as those found previously by the course organizer using a laborious trial-and-error approach. We investigate how the quality of the allocation is affected by the ratio of the number of projects offered to the number of students and the number of projects ranked by each student. We briefly discuss how our approach can be generalized to include other types of constraints and discuss its potential applicability to wider allocation problems.

Outreach


Women in Physics

NWP conference 2018

I am passionate about promoting women in science and helping to inspire young girls to get into science. For the past three years, I have been on the committee for the Network of Women in Physics (NWP) at the University of Bath:

The aims of the group are the following:

NWP Conference poster
NWP International Women's Day Quiz Night
Wonder Women of Space Exhibition at the Herschel Museum

Bath Astronomers

BathAstronomers
BathAstronomers

Bath Astronomers is a group passionate about astronomy and sharing the skies through adhoc or public observing sessions and educational outreach activities in and around Bath. After being a member of the Bath Astronomers group for two years, I have recently (Nov 2019) joined the committee as an Ordinary Officer.

CV


Link to CV

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