Seminar

Probing the stellar graveyard and dark matter with astrometric microlensing

September 6, 2024

Peter McGill

We are in the golden era of high-precision astrometric observatories. Gaia will complete its decade-long astrometric survey of the entire sky this year. Roman will soon start the Galactic Bulge Time Domain Survey. Moreover, the James Webb Space Telescope, Roman, and Euclid will all be available as astrometric follow-up resources. This presents an unprecedented opportunity to take advantage of the astrometric signatures of microlensing events. Astrometric microlensing has the potential to provide powerful and complementary information beyond what is possible with photometry alone. I will present some of the benefits of having real-time astrometry both simultaneously with photometry and as a probe on its own. I will focus on the implications for characterizing populations of dark and isolated objects such as neutron stars, black holes, and compact dark matter. Finally, I will present a new open-source software package called popclass. Popclass enables a probabilistic classification of the lens of a microlensing event given a light curve and will allow the efficient allocation of astrometric follow-up in the era of large upcoming ground-based surveys such as the Legacy Survey of Space and Time.

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