Wine and Cheese Spring 2019

This page records the schedule, titles and abstracts of the JHU/STScI CAS Astrophysics Wine & Cheese Series in Spring 2019.

Wine and Cheese sessions with one talk will have a 50 minute talk with 10 minutes for questions. Sessions with two speakers will have two 25 minute talks, each with 5 minutes for questions. Sessions in the Graduate Student Series will have three 15 minute talks, each with 5 minutes for questions.

February 4th

James Owen (Imperial College)

Understanding the formation and evolution of the Kepler Planets
The observed exoplanet population unveiled by Kepler is billions of years old, distinctly separated in time from the planet formation process that only lasted ~10-100 Myr. I will argue that atmospheric escape has been one of the key evolutionary drivers shaping the exoplanet population we observed today. By understanding how these planet evolve in time, I will show we can place some intriguing constraints on how they formed.

February 11th

Dillon Brout (UPenn)

First Cosmology Results Using Type Ia Supernova from the Dark Energy Survey
Today, now 20 years after the discovery of the acceleration of the universe, the Dark Energy Survey (DES) Supernova Program has discovered thousands of Type Ia Supernovae (SNe Ia) useful for cosmological measurements. In this talk I will present the first analysis of a small subset of 207 spectroscopically confirmed SNe Ia discovered during the first 3 years of the DES Supernova Program. I will show why this state of the art dataset provides constraints competitive to measurements using aggregate samples of >1000 SNe Ia, and I will forecast the full 5 year DES photometrically classified sample.

February 18th

Matthew Petroff

3D-printed Millimeter Wave Absorbers
Additive manufacturing in the form of 3D printing has become increasing widespread in recent years. As this technology can produce submillimeter-sized features, it has potential uses in instrumentation and optics for millimeter wave astronomy, such as in Cosmic Microwave Background experiments. This talk will discuss the application of such technology to the development of a broadband millimeter wave absorber printable via the extrusion of a carbon-loaded thermoplastic.

Jonathan Aguilar

Discovering Benchmark Low-Mass Companions with High-Contrast Imaging
In recent decades, a number of high-contrast imaging surveys have searched for low-mass stars, brown dwarfs, and planetary-mass companions at separations that are mostly inaccessible with other techniques. In wide-field surveys, they are buried underneath the bright PSF of the primary star, and in spectroscopic surveys, they appear only as a long and typically linear radial velocity trend. The slow nature of high-contrast observing means that the distribution in mass and separation of these companions, which link the close- and far-separation populations, is only now beginning to be revealed. We discuss the discovery and characterization of one such object, our prospects for measuring a dynamical mass, and place it in context with the known population of low-mass companions at separations of tens to hundreds of AU.

Caroline Huang

A Mira Distance to Supernova Host Galaxy NGC 1559
One of the most exciting emerging issues in extragalactic astronomy and precision cosmology is the tension between the most precise locally-measured Hubble Constant and the one inferred from the cosmic microwave background (CMB) data assuming a Lambda CDM cosmology. New distance indicators, like Mira variables, can help provide a check to local Cepheid distance, increase the number of local calibrators for Type Ia Supernovae (SNe), and allow us to match the demographics of the calibrating sample of SNe to the Hubble flow sample more closely. In my talk, I will present the first Mira-based distance to a Type-Ia SNe host galaxy, NGC 1559, and discuss the feasibility of using Mira variables as an alternative distance indicator to Cepheids.

February 25th

Paul Schecter (MIT)

Twinkling Quasars: a Strong Limit on the Contribution of LIGO-mass Primordial Black Holes to the Cosmological Dark Matter Density
On rare occasions, a galaxy acts as gravitational lens producing multiple images of a quasar directly behind it. The stars within this galaxy then act as micro-lenses, breaking up the "macro-images" into "micro-images". As the stars move, the macro-images twinkle -- the gravitational analog of atmospheric scintillation. Counterintuitively, the amplitude of the twinkling does not increase monotonically with stellar density, and instead decreases at high optical depth. A single strongly micro-lensed quasar can set a significant upper limit on the graininess of the gravitational potential. The poster-child for such a limit is SDSS0924+0219 for which at least 50% of the lens' surface mass density must be in a smooth component rather a than grainy one. A sample of ten lensed quasars gives a 10% upper limit on the contribution of LIGO-mass primordial black holes to the cosmological dark matter density after discounting the graininess due to the observed stars.