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Research
Colloquium Series

All talks are held on Wednesdays in the STScI John N. Bahcall Auditorium at 3:30 p.m. preceded by tea at 3:15 p.m.

Please direct questions or comments to the colloquium committee. The 2018-19 committee members are Jason Tumlinson (Chair), Alaina Henry, Lea Hagen, Ethan Vishniac (JHU Co-chair), Kevin Schlaufman (JHU), and Kate Rowlands (JHU).

STScI presents live and archived webcasting of talks and Colloquium Series.

Date Speaker/Title
Sept. 05 Jennifer C. Yee (Harvard-Smithsonian Center for Astrophysics)
Title: Microlensing Perspectives on Cool Planet Populations
Abstract: Microlensing is uniquely capable of studying planets across a wide range of masses at a few AU from their host stars. At the lower masses, these planets are difficult to impossible to find with other techniques. I will discuss recent results in microlensing suggesting a turnover in the planet mass ratio function around 10^-4, i.e. that planets with mass ratios similar to Neptune are the most abundant at separations probed by microlensing. I will also discuss microlensing constraints on the free-floating planet population. Finally, I will discuss how current and future microlensing surveys, including WFIRST, will advance our understanding of cool planet populations.
Host: TBD
Sept. 12 Misty Bentz (Georgia State University)
Title: Black Hole Masses in Active Galaxies
Abstract: One of the unexpected results from 25 years of observations with the Hubble Space Telescope is the discovery that supermassive black holes inhabit the centers of all massive galaxies, and these black holes appear to have a symbiotic relationship with their host galaxies. In order to further our understanding of this unexpected relationship, the masses of the black holes must be determined. However, black hole mass measurements are difficult to achieve because they require direct observations of the black hole's gravitational influence on luminous tracers. A few different techniques have been developed over the last 25 years to meet this goal. One technique, known as reverberation mapping, is exclusively applicable to active black holes but may be used for even the most distant quasars in our universe, providing a way to study black holes across history. On the other hand, the most widely used technique in the local universe requires exquisite spatial resolution and is based on observations of the bulk motions of stars deep in the nucleus of a (usually inactive) galaxy. I will introduce these techniques and describe our ongoing program to identify a small sample of galaxies where multiple black hole mass techniques can be applied to each galaxy. This effort includes our recently-approved JWST ERS program, as well as programs carried out on multiple moderate- and large-aperture ground-based telescopes. The results of this work will allow us to directly test these independent mass measurement techniques against each other, investigating whether all black hole masses are on the same scale and thus having implications for our understanding of the evolution of galaxies across the ~13 billion year history of the universe.
Host: TBD
Sept. 19 No Colloquium
Sept. 26 No Colloquium
Oct. 03 No Colloquium
Oct. 10 No Colloquium
Oct. 17 TBS (TBS)
Title: TBS
Abstract: TBS
Host: TBD
Oct. 24 Laurent Pueyo (Space Telescope Science Institute)
Title: Exoplanet Imaging: From Precision Optics to Precision Measurements
Abstract: I will first present recent observational results pertaining to the formation history of giant planets. This work was mostly carried out using the Gemini Planet Imager instrument: I will highlight our group’s successful effort to deliver a uniform and self-consistent family portrait of the atmospheric compositions and orbital properties of nearby young Jupiter analogs. I will discuss what these results teach us about Jovian planet formation, and how they can be completed by ongoing HST and future JWST observations. I will then delve into future experiments aimed at identifying biomarkers in the atmosphere of temperate earth analogs. I will present our group’s recent results on optimizing earth finding coronagraphs with large segmented apertures in space. Finally, I will discuss current challenges in space based high-contrast instrumentation, along with my vision for both science and technology roadmaps towards a Large UV/Optical/IR (LUVIOR) Surveyor.
Host: N/A
Oct. 31 Sergey Koposov (Carnegie Mellon University)
Title: Galactic Archeology in the Gaia Era
Abstract: Galactic archaeology is the field that studies tiny remnants and traces of processes that lead to the formation of our Galaxy. In the past decade, this field was pushed forward by large imaging surveys, allowing us to detect large populations of faint dwarf galaxies around the Milky Way, discover new stellar streams and probe the Milky Way stellar halo in unprecedented detail. This year, however, this field was revolutionized by the arrival of Gaia astrometric dataset that for the first time offers a 3-D map of our Galaxy, as well as provides precise proper motions for more than a billion stars. In my talk, I will discuss some of the recent results and discoveries of various sub-structures in the Milky Way halo done before the arrival of the Gaia data as well as highlight some of the interesting fresh results obtained with the help of Gaia.
Host: TBD
Nov. 07 Susan Kassin (Space Telescope Science Institute)
Title: Toward a New Understanding of Galaxy Evolution
Abstract: TBS
Host: N/A
Nov. 14 Kate Rubin (San Diego State University)
Title: On the Morphologies of Cool Circumgalactic Gas Flows: Insights from Absorption- and Emission-Line Tracers
Abstract: TBS
Host: TBD
Nov. 21 No Colloquium
Nov. 28 Karen Masters (Haverford College)
Title: Galaxy Morphology in the Era of Large Surveys
Abstract: TBS
Host: TBD
Dec. 05 Roland Bacon (University of Lyon)
Title: The MUSE 3D View of the High Redshift Universe
Abstract: Thanks to its unique capabilities, the MUSE integral field spectrograph at ESO VLT has given us new insight of the Universe at high redshift. In this talk I will review some breakthrough in the observation of the Hubble Ultra Deep field with MUSE including the discovery of a new population of faint galaxies without HST counterpart in the UDF and the ubiquitous presence of extended Lyman-alpha haloes around galaxies.
Host: TBD
Dec. 12 Andrew Wetzel (University of California-Davis)
Title: Simulating the Milky Way and Its Satellites
Abstract: I will present the Latte suite of cosmological zoom-in baryonic simulations that model the formation of Milky Way-like galaxies at parsec-scale resolution, using the FIRE (Feedback in Realistic Environments) model for star formation and feedback. First I will discuss the formation of the Milky Way, including the origin of its thin+thick stellar disk morphology and new insights into the elemental abundances of its stellar populations. I also will present predictions for the oldest and most metal-poor stars in/around the Milky Way. The Latte simulations also self-consistently resolve the formation of satellite dwarf galaxies around each Milky Way-like host. While these low-mass galaxies have presented significant challenges to the cold dark matter model, I will show progress in addressing the "missing satellites" and "too-big-to-fail" problems. I also will present predictions for the orbital and star-formation histories of these satellites, and discuss a new long-term HST Treasury program to measure proper motions and star-formation histories for all known satellites of the Milky Way. Finally, I will discuss the synthetic Milky Way surveys that we have created from the Latte simulations, which are publicly available to provide theoretical modeling insight for the era of Gaia.
Host: TBD