A list of my publications can be found on my Inspire page.

Current & recent projects

  • DES Year 3 extended cosmological models - The Dark Energy Survey (DES) is an ongoing project to map 1/8th of the sky, and to use the information gathered from that survey to place constraints on, among other things, dark energy properties. With Agnes Ferte (JPL), I am coleading the DES analysis team focused on constraining extended (beyond wCDM) models with galaxy clustering and weak lensing data gathered during DES’ first three years. We’re focused on several phenomenological parameterizations of physics beyond the cosmological standard model, including time-dependent dark energy, sterile neutrinos, modified gravity, non-zero curvature, and non-parametric measurement of large scale structure growth.

  • Blinding for multi-probe cosmological analyses - As cosmological experiments grow increasingly precise, it is important to make sure experimenters’ biases don’t unconsciously influence the results. An important tool for doing this is a framework of experiment design, known as blind analysis, in which the data are manipulated in some way to conceal the true results until after all decisions about how to perform the analysis are made. To be effective, the transformations on data used for this must be able to hide the results of an analysis while preserving the properties of the data such that necessary validation tests can still be performed. I’ve developed and tested a new, simple, and effective data transformation that can conceal the results for combined analyses of multiple cosmological observables. Our method, described in this paper, is being used in the the DES Year 3 combined galaxy clustering and weak lensing analysis, and could be potentially applicable to both future surveys and other types of data.

  • Growth-geometry split analysis of DES data - Many models of modified gravity can produce the same expansion history as LCDM, the standard cosmological model of a cosmological constant + cold dark matter + general relativity, but will differ in their predictions for structure growth. The idea of the grow-geometry split analysis is to separately constrain the LCDM parameters using probes of expansion and structure growth, and then to use the comparison of those constraints as a consistency test of LCDM. I’m currently performing this kind of analysis on the Year-1 data for DES. I’m also generally interested in using galaxy survey data to test for modified gravity via phenomenological parameterizations of deviations from general relativity.

  • CMB anomaly covariances - For the most part, data from the CMB have been found to be in remarkable agreement with the predictions of LCDM. However, there are a handful of features on very large angular scales which are statistically unlikely in LCDM, which have been the subject of much study. This paper describes a project I did using simulated CMB skies to characterize the extent to which these various anomalies are independent.

  • ISW signal reconstruction - The integrated Sachs-Wolfe (ISW) effect is a result of the fact that the energy of cosmic microwave background (CMB) photons gets modulated when pass through gravitational potential wells associated with large scale structure (LSS) on their way from the surface of last scattering to us. This energy modulation contributes to CMB temperature anisotropies at large angles. One can use theoretical cross correlations and maps of LSS tracers to try to reconstruct a map of the ISW signal. In two papers (here and here), I explored how different survey properties and systematics affecting the input galaxy maps impacted the accuracy of this kind of ISW signal reconstruction.

  • Astrophysical black holes and modified gravity - For a master’s project, I did an exploratory study of how the infall of objects into black holes would be affected by a class of extensions to general relativity in which a new gravitational field interacts with matter in the black hole’s accretion disk. The project is described in this paper.

Other activities

Though I can’t really claim it as a project, I was lucky enough to be on observing shift during the tail end of the DES follow-up observations of the binary neutron star collision detected by LIGO in August 2017. Data I took played a small role in these three papers.