College of Science

Seminar: Breanna Binder [Cal Poly Pomona]

How Massive Are the Heaviest Stellar Black Holes?

Apr 27, 2017 11:00 AM to Apr 27, 2017 12:00 PM at

Astrophysical black holes come in two distinct mass regimes: stellar mass black holes are typically 5-10 times the mass of the Sun and are the corpses of the most massive stars, while supermassive black holes that live at the centers of galaxies can have masses ranging from millions to billions of times the mass of the Sun. Stellar mass black holes – particularly the most massive – are the modern-day analog to the primordial “seeds” from which supermassive black holes grew, and black holes in massive binary star systems are the direct progenitors of double-degenerate systems that are expected to be a leading producer of gravitational waves. I will discuss observations of two massive “twin” Wolf Rayet + black hole binary systems, IC 10 X-1 and NGC 300 X-1. These systems were previously believed to contain the two heaviest stellar mass black holes in the local universe, but recent observations have shown (1) these prior mass estimates are unreliable, and (2) a new model of black hole binaries which accounts for the accretion disk-stellar wind interactions with the companion star is needed to obtain accurate black hole mass measurements.