Nicole Crumpler

Ph.D

Astrophysics

Physics

William H. Miller, III Department of Physics & Astronomy, Johns Hopkins University

SDSS V White Dwarf Group Researcher

• Coded in Python and Pandas to consolidate a catalog of more than 42,000 SDSS DA white dwarf spectra, the largest data set of its kind. Obtained SDSS and Gaia photometry for each object using SQL, and matched objects in this catalog with 11 other published white dwarf catalogs, re-processed to each have consistent formatting. • Fit the radial velocities, radii, and photometric temperatures of every object using 𝜒^2-minimization and model spectra. Measured the surface gravity and spectroscopic temperature of every spectrum using both a generative fitting pipeline built with TensorFlow and a Random Forest routine built with Scikit-Learn. Implemented multiprocessing to make fitting speed 7x faster. Validated these fits against other datasets to determine optimal fit parameters, which results in all measurements meeting benchmarks that significantly surpass the standards of the field by a factor of 2. Outlined my measurement procedures in a paper submitted to the SDSS collaboration for review. • Bias-corrected this catalog using MCMC simulations, and used the results to detect the temperature dependence of the white dwarf mass-radius relation at >99.99% confidence, the first ever detection of this effect with a large catalog. Summarized this detection in a second paper submitted to the SDSS collaboration for review.