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Probes of galaxy interactions: from the Magellanic Stream to lensed supernovae

We have been working on a variety of projects, which are generally connected by trying to understand the distributions of dark matter. First, we used hydrodynamic simulations of the Magellanic Stream to estimate the mass of the MW potential. The simulated streams are sensitive to the MW potential because the potential determines the orbits of the satellites. The orbits determine the strength of the tidal interactions and ram pressure stripping in the simulations that cause stream formation. We estimated the total mass of the potential by matching the simulated stream lengths to the observations across simulations with different MW potentials. Currently, we are working on combining local acceleration measurements with constraints from stellar streams to model the MW potential. There are now local direct acceleration measurements from binary pulsar systems, which can calibrate potential models while fitting to dynamical probes of the potential. Now I am focused on using gravitationally lensed supernovae to measure accurate time delays in strong lensing systems. We run simulations of lensed supernovae in systems with gravitational microlensing, preparing to avoid contamination from microlensing in these systems. We model the magnification patterns caused by microlensing and convolve them with supernova models to simulate spectra from microlensing systems. This produces spectra with different microlensing realizations, allowing us to study the effects of microlensing on the spectra. Accurate time delay measurements can put a strong constraint on the Hubble constant and to search for dark matter substructure along the line of sight.

Speaker: Peter Craig, Rochester Institute of Technology

Monday, 09/26/22


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Varian Physics Building

382 Via Pueblo Mall
Room 355
Stanford, CA 94305