Tyler Holland-Ashford

Tyler Holland-Ashford

Graduate Student

The Ohio State University

Biography

I am currently working with Professor Laura Lopez on X-ray observations of supernova remnants (SNRs). Our goal is to, through spatially resolved imaging and spectral analysis, study the distribution and properties of ejecta in SNRs and learn more about the processes that occur during supernova explosions.

During my time at OSU, I have analyzed data from Chandra, XMM-Newton, ROSAT, and Suzaku X-ray telescopes. In my first projects, I investigated the asymmetries of both bulk ejecta in multiple SNRs and specific elements in the SNR Cassiopeia A, performing spectral fitting using the X-ray analysis software Xspec and AtomDB. I quantified the ejecta asymmetries and compared them to each other and NS kick velocity, finding that NSs are preferentially kicked opposite to the bulk of ejecta. In another project, I studied recombining plasma in the SNR W49B, creating spectral fits to 46 regions in the remnant in order to investigate the properties and presence of overionized plasma and constrain the origin of rapid cooling.

I am currently working on quantifying individual elements’ asymmetries in SNRs other than Cassiopeia A (for which I led a successful Chandra archival proposal to support) and measuring the mass ratios of Fe-group elements in MW and LMC Type Ia SNRs. The former project will build on my previous analysis of asymmetries in SNR ejecta, and the latter will be used to place constraints on Type Ia SNe progenitors through comparison to the results of 3D SNe simulations. In the future, I will make use of the incredibly detailed spectra from microcalorimeters like XRISM to study the 3D distribution of and make precise measurements of ejecta metals and plasma properties in SNRs.

Interests

  • Supernova Remnants
  • X-ray Imaging
  • X-ray Spectroscopy
  • Neutron Star Kicks
  • Supernova Explosion Mechanisms
  • Atomic Data & Modeling

Education

  • PhD in Astronomy, expected, 2021

    The Ohio State University

  • M.S. in Astronomy, 2017

    The Ohio State University

  • B.S. in Physics, 2015

    Harvey Mudd College

Publications

Spatially-Resolved Study of Recombining Plasma in W49B Using XMM-Newton
Evidence of a Type Ia Progenitor for Supernova Remnant 3C 397
Asymmetries of Heavy Elements in the Young Supernova Remnant Cassiopeia A
The Age Evolution of the Radio Morphology of Supernova Remnants
Measurement of the Core-collapse Progenitor Mass Distribution of the Small Magellanic Cloud
Comparing Neutron Star Kicks to Supernova Remnant Asymmetries

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