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Chelsea E. Harris

models supernovae

Collisions with Circumstellar Material
Formation of Magnetically-Confined Jets

Suite Modeling

Hundreds of one-dimensional models explore parameter space.

Code Writing

High-order algorithms for next-generation supercomputers.

Observations

Analysis, proposals, assistance with the application of models.

Inreach & Outreach

Guidance for new scientists and connecting with the public.

About
  • Curriculum Vitae

  • Highest Degree

    PhD in Astrophysics, University of California Berkeley (2018)

  • Current Position

    postdoctoral researcher, Michigan State University

    Contact

    harr1561 (at) msu (dot) edu

  • Publications

    ORCiD: 0000-0002-1751-7474
    ADS list of publications

  • full CV

  • Background Blurb
  • Chelsea Harris (she/hers or they/theirs) is from southern California. They began undergraduate study in 2008 in the College of Creative Studies at the University of California Santa Barbara (UCSB). While at UCSB, they did observational research on active galaxies in the group of Tommaso Treu. They received their Bachelor of Science in Physics in 2012 and moved to the University of California Berkeley for graduate study in the Department of Astronomy and Astrophysics. There, they pursued theoretical research in Type Ia supernovae, advised by Peter Nugent and Dan Kasen, focusing on using theory to interpret and predict supernova observations. In 2013 they were awarded a Department of Energy Computational Science Graduate Fellowship. Their PhD dissertation focused on models of Type I supernovae interacting with a distant circumstellar medium to constrain mass-loss and mass-transfer processes in binary supernova progenitor systems. They have been at Michigan State University since 2018 as a postdoctoral researcher, first in the group of Sean Couch implementing high-order multi-dimensional magnetohydrodynamics in the FLASH code and now in the group of Laura Chomiuk performing hydrodynamic and radiation transport modeling of Type Ia supernova interaction with circumstellar material. In 2021, they were awarded an NSF grant for theoretical and archival studies of SN Ia late-time interaction at optical and UV wavelengths. For several years they helped organize Astronomy on Tap Lansing and they now run an outreach group for undergraduates. For "inreach," they advocate for student mental wellness. Their numerous hobbies are centered on outdoor activities, the arts, and videogames.
Research

Delayed Interaction in Type Ia Supernovae

Type Ia supernovae occur in binary systems that have a carbon-oxygen white dwarf gaining mass from an unidentified companion. The circumstellar medium (CSM) is a key discriminant of the companion, because it is made up of companion material and shaped by the mass donation process. The discovery of SNe Ia that collide with CSM over a month after explosion requires new models and new systems of observations.

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Selected Literature

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Delayed Interaction in Core-Collapse Supernovae

Core-collapse supernovae are observationally distinguished by the amount their envelopes have been lost. The process by which the massive hydrogen and helium envelopes are stripped from the star to create SNe Ibc is unknown. The discovery of SNe Ibc that collide with CSM over a month after explosion can shed light on the timescale of envelope loss.


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Selected Literature

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Core-Collapse Supernova Magnetohydrodynamics

Some Type Ic supernovae are associated with long gamma-ray bursts thus we know it is possible for the core collapse to create a relativistic, confined jet. The amplification of existing magnetic fields in the star by the conversion of rotational energy is likely the mechanism behind this phenomenon.



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Selected Literature

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Collaborations

The teams I'm a part of — click to expand.

If you'd like to collaborate, please e-mail me (harr1561 [at] msu [dot] edu).

Students Mentored

  • Cassandra Tang, at UC Berkeley
  • Brandon McIntyre, at Michigan State University
  • Jax Hernandez, at Michigan State University
  • Miranda Pikus, at Michigan State University
  • Brandon Barker, at Michigan State University

Thinking of working with me? Here's what you need to know.

General expectations

For all students:
  • We will complete a Mentor-Mentee Agreement form at the beginning of your first project (examples here ).
  • We will set production goals and create your Project Timeline for achieving them, and assess progress together.
  • It is 100% fine for your long-term career plan to not be science research (or astronomy, or supernova theory).
  • Engage in a daily writing practice.

Summer research. To engage in a summer research project with me, you need to have experience in programming — does not matter which language, as I will expect you to adapt to the language used. If you are keen on writing a paper with me, we will need more than one summer.

Longer-term research. As your research mentor, I am your advocate — I will be responsible for promoting and defending your work, and helping you achieve your career goals. The type of person I want to advocate for is someone who is considerate of and respectful to others, and values communication skills and emotional intelligence skills (these are skills, there's no "one right answer", and you don't have to be perfect). This is because these skills affect your own research productivity, the productivity of our community, and our ability to make science inclusive.

What is it? SNAPhU is the computational research group led by Professor Sean Couch that simulates core-collapse supernovae and their progenitors to connect observations to core properties and the explosion mechanism. The team primarily using the FLASH code base, and the High Performance Computing Center (MSU) and Argonne Leadership Computing Facility supercomputers.

How do I fit in? I am a postdoctoral researcher in this group, emphasizing my research for TEAMS. I also help organize and run group meetings and mentor students in research.

Who's in it?

What is it? Stray Duck is the observational research group led by Professors Jay Strayder ("Stray") and Laura Chomiuk ("Duck"). The team studies novae, supernovae, and other transients related to accretion onto compact objects.

How do I fit in? I collaborate with Chomiuk on projects involving Type Ia supernovae impacting circumstellar material. I have been included on VLA proposals with group members, contributing comparisons with numerical models.

Who's in it? Stray Duck is a large group with diverse research interests; here I list the members with whom I particularly collaborate.

What is it? HADES is a survey to discover delayed interaction in SNe Ia using narrow-band H-α imaging. Follow-up is obtained to confirm H-α. Its candidate list focuses on old supernovae from the 91T and 91bg sub-classes.

How do I fit in? I am primarily a voyeur at this stage, giving input about what might be physically interesting targets. I gave some small assistance with the original survey design. My models can help guide our expectations for non-optical follow-up, and assist interpretations of the data.

Who's in it?