Wine and Cheese Fall 2025

This page records the schedule, titles and abstracts of the JHU/STScI CAS Astrophysics Wine & Cheese Series in Fall 2025.

Wine and Cheese sessions with one speaker will have a 50 minute talk with 10 minutes for questions. Sessions with two speakers will have two 25 minute talks, each with 5ish minutes for questions.(Since when have you ever seen a question session cut short if everyone is interested?)

25 August

John Silverman (IPMU)

Evolution of Supermassive Black Holes and their Host Galaxies at z > 6 with JWST
Clues on the formation of supermassive black holes may be found in the properties of their host galaxies and mass relations with cosmic time. We will present results from JWST programs based on the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) at z > 6. The detection of the host galaxies enables the first assessment of the intrinsic ratio between black hole mass and stellar mass with consideration of selection effects and measurement uncertainties. Furthermore, new results will be presented on the detection of lower mass black holes, which highlight a large population of undermassive black holes at z > 6 just beginning to be tapped by JWST.

08 September

Valerio De Luca (JHU)

Primordial Black Holes: a Gravitational Wave Quest
Primordial black holes are a fascinating family of black holes that may have formed in the early universe and are considered a potential candidate for the dark matter. After briefly reviewing their formation mechanism and evolution throughout cosmic history, we explore their detectability via gravitational waves. In particular, we focus on signals emitted both during their formation and from the merger of associated primordial binaries. Finally, we highlight potential smoking-gun signatures that could probe their existence in future gravitational wave observatories, such as the Einstein Telescope and LISA.

David Stark (JHU/STScI)

21cm Follow-up for the MaNGA Survey: Past Results and Future Directions
The HI-MaNGA survey is a large observing campaign using the 100m Green Bank Telescope to obtain 21cm measurements for galaxies in the SDSS-IV Mapping Nearby Galaxies at APO (MaNGA) survey. HI-MaNGA provides important constraints on the cold neutral atomic hydrogen gas, or HI, in the MaNGA sample. HI acts the fuel reservoir that sustains star formation over long timescales, so understanding the physical processes that influence it is critical to our understanding of galaxy evolution. I will describe the HI-MaNGA survey and its current status, as well as highlight some recent results using this data set. I will conclude with a description of future NSF-funded efforts to complete the survey, and use it to understand the wide diversity of HI depletion times in z~0 star forming galaxies. ~

15 September

Natalie Myers (JHU)

Tracing the Chemical Enrichment of the Milky Way using Star Clusters: Measurement and Analysis of Neutron Capture Elemental Abundances
The chemistry of stars in the Milky Way is a powerful tool for exploring the enrichment history of the Galaxy. With the all-sky spectroscopic surveys that are currently available to us, using chemistry as a means to study the evolution and history of the Milky Way and potentially characterize the ages of different stellar populations therein has flourished. Open clusters have long been used to determine ages of stars, helping to calibrate stellar evolution models and other methods of age dating stellar groups (e.g., gyrochronology and asteroseismology). In this work, we utilize the Open Cluster Chemical Abundances and Mapping (OCCAM) survey, which uses SDSS-IV/APOGEE to establish cluster membership and has already been used to study the chemical evolution of the Milky Way (Myers et al. 2022, Spoo et al. 2022). Using this infrared-based dataset as a foundation, we target stars with the Keck I and Magellan Baade telescopes to collect high-resolution (R > 50,000), high-S/N (>75 at 5500A), optical spectra for 56 stars in 18 open clusters. With these data, we derive abundances for 23 elements using BACCHUS, including 7 neutron capture abundances not measurable by APOGEE. Finally, we use these neutron capture abundances to characterize the distribution of these elements radially and chronologically in the Milky Way. We find that elements in the neutron-capture families exhibit significantly flatter gradients as compared to the lighter alpha and iron-peak elements. In addition, we find the abundance each of the elements exhibits large scatter and little mean variation through time. These results could indicate that the enrichers for the heavier elements are well-distributed throughout the Milky Way's thin disk, and that the ISM has stayed relatively well-mixed through time.