Astrophysics & Planetary Sciences Colloquium

Solar Flares: Nature’s Laboratory for Magnetic Reconnection

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Solar flares and coronal mass ejections (CMEs) are powered by the sudden release of magnetic energy stored in the Sun’s low corona as a result of magnetic reconnection. Understanding these explosive events requires tracking how magnetic fields evolve—not only during, but also before the eruptions. Yet direct measurements of the 3D coronal magnetic field remain a major challenge. In this talk, I will overview what we currently know about the structure of the pre-eruption magnetic field and the physical mechanisms that trigger eruptions.

POSTPONED: 2 Fast, 2 Furious? Galaxy and Black Hole Formation in the JWST Era

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Abstract: The launch and commissioning of the James Webb Space Telescope is ushering in a new era in our understanding of our cosmic origins. Galaxies are a fundamental building block of the universe, yet how they formed has remained enigmatic owing to our inability to observe them at early cosmic times. In just its first three years of operation, JWST has already upended our understanding of galaxy and black hole growth in the early universe.

Field stars and their kinematics as a probe of massive star evolution and binary populations

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Abstract: Field massive stars are more easily identified and studied than those in crowded cluster environments.  While some massive stars may form in relative isolation, most are ejected from clusters via dynamical processes and supernova kicks in binary systems.  Since both mechanisms are driven by binarity in the massive star population, field stars and their kinematics probe the effects of binarity, which can strongly influence stellar evolution by the tr

Formed too Fast? Massive Galaxies at Cosmic Dawn

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Abstract: A growing number of surprisingly massive galaxies are now being found in the first ~billion years after the Big Bang that push the limits of theoretical predictions within Lambda-CDM. Unusually bright high-redshift galaxies discovered by JWST challenge our most fundamental models of how fast stars form. Some of them contain overly massive black holes whose formation is uncharted. Massive dusty starbursts found with ALMA are requiring new explanations about early dust production.