Speaker: Michael Martinez, Physics PhD Graduate Student
Abstract: Strong Gravitational Lensing, the phenomenon by which a background source is magnified and split into multiple images by a massive foreground object, is one of the most versatile tools to modern astrophysicists, with applications to everything from studying high-redshift galaxy evolution to measuring the Hubble Constant. As lensing is sensitive to all mass along the line of sight from the lensed source to the Earth, it offers sensitivity to dark matter halos even if no luminous stellar population is present. Radio wavelength Very Long Baseline Interferometry (VLBI) observations, which provide milliarcsecond resolution and complement existing optical and infrared studies, are ideal for measuring the perturbations caused by these low-mass halos. In this talk, I present the results of a pilot project to discover new radio-loud gravitationally lensed sources. Using Very Large Array (VLA) follow-up to VLA Sky Survey (VLASS) selected lens candidates, we report 5 new radio-loud gravitational lenses, a 10% increase in the present sample size. I will also discuss plans for future observations in which we expect to further extend this sample by 50%, laying the groundwork for a statistically robust VLBI program to provide new constraints on dark matter.