Dept Colloquium: Drs. Lia Hankla & Hayley Beltz, UMD Astronomy

Connecting Black Hole Accretion Disks, X-ray Coronae, and Winds

Speaker: Dr. Lia Hankla, UMD Astronomy

Abstract: Probing the evolution of black holes, jets, and winds requires understanding the radiation and dynamics of the plasmas in the black hole's immediate vicinity. However, these plasmas often span widely varying physical regimes that affect what we observe across scales and wavelengths. In this talk, I will discuss several models for the plasmas in these regimes and how they can help understand problems such as the origin of the X-ray corona, state transitions in X-ray binaries, and black hole spin measurements. I will highlight how combining these models with multiwavelength observations, particularly the detection of millimeter emission from the nuclear regions of radio-quiet AGN, reveals the need for a wind launched from the inner X-ray emitting regions.

A Tale of Two B-Fields: Magnetically Dominated Circulation of Hot and Ultrahot Jupiters

Speaker: Dr. Hayley Beltz, UMD Astronomy

Abstract: Magnetic fields shape the atmospheric circulation of solar system planets, but have yet to be conclusively detected on any exoplanet. In this talk, I will focus on my work these past few years at Maryland modeling the atmospheres of the hottest gas giant exoplanets--hot and ultrahot Jupiters. The dayside of these planets reach such extreme temperatures that most atmospheric species are thermally dissociated, which results in charged particles that resist flow over magnetic field lines. This significantly alters the large-scale circulation on the planet, causing reduced hotspot offsets and stronger day-night temperature contrasts compared to non-magnetic models.  I will discuss the observational implications of this magnetic circulation regime in high resolution spectroscopy and JWST eclipse mapping and highlight future avenues for potentially detecting and constraining exoplanet magnetic fields.

Host: Dr. Benedikt Diemer