Colloquia Schedule

Alex Szalay, Johns Hopkins University
Thursday, February 22, 2018
3:45 p.m.
LGRT 1033
Title:
New Challenges in Astrophysics with Large Datasets
Abstract:
The talk will present the new emerging challenges in the Era of Surveys. As these surveys produce billions of objects, the usual statistical errors are no longer the bottleneck, but we have to address a new problem of systematic errors. Supercomputer simulations are also emerging as new instruments, capable of generating petabytes of data. These Big Data challenges require new skills and techniques. As a result, the next generation of astronomers have to be equally at home in data science and astrophysics.
Ryan Hickox, Dartmouth College
Thursday, March 1, 2018
3:45 p.m.
LGRT 1033
Title:
The Hidden Monsters: New Windows on the Cosmic Evolution of Supermassive Black Holes
Abstract:
At the heart of essentially every large galaxy in the Universe lies a supermassive black hole. In the past decade, surveys of the extragalactic sky have made great progress in understanding the cosmic growth of these black holes, as they "eat" surrounding material and radiate as active galactic nuclei (AGN). However, our picture of black hole evolution has remained incomplete, due to the challenges of detecting black holes that are highly obscured by gas and dust or hidden beneath thelight of their host galaxies. With the advent of new resources including hard X-ray observations from NuSTAR, mid-infrared data from WISE, and new insights from theoretical models, we can now identify millions of these “hidden” growing black holes across much the sky, and characterize the nature of their obscuration and their role in the formation of galaxies. I will describe recent efforts to characterize these "hidden” black holes, particularly highlighting work by our group at Dartmouth, and will present evidence that (at least some) powerful obscured AGN represent an evolutionary phase in the evolution of their host galaxies. Finally, I will point to the exciting potential for future of AGN population studies with the next generation of extragalactic surveys, including with NASA's Lynx concept X-ray mission.
Keith Hawkins, Columbia University
Thursday, March 8, 2018
3:45 p.m.
LGRT 1033
Title:
Galactic Archaeology in the Gaia Era
Abstract:
One of the key objectives of modern astrophysics is to understand the formation and evolution of galaxies. In this regard, the Milky Way is a fantastic testing ground for our theories of galaxy formation. However, dissecting the assembly history of the Galaxy, requires a detailed mapping of the structural, dynamical chemical, and age distributions of its stellar populations. Recently, we have entered an era of large spectroscopic and astrometric surveys, which has begun to pave the way for the exciting advancements in this field. Combining data from the many multi-object spectroscopic surveys, which are already underway, and the rich dataset from Gaia will undoubtedly be the way forward in order to disentangle the full chemo-dynamical history of our Galaxy. In this talk, I will discuss my current work in Galactic archaeology and how large spectroscopic surveys have been used to dissect the structure of our Galaxy. I will also explore the future of Galactic archaeology through chemical cartography.
Jackie Faherty, AMNH
Thursday, March 22, 2018
3:45 p.m.
LGRT 1033
Title:
Brown Dwarfs Reveal Exoplanet Secrets
Abstract:
The future of directly imaged exoplanet characterization studies lies with the next generation of Telescopes. While exciting exoplanet discoveries have been made with current facilities, we have primarily been left with open questions as to the formation, evolution and current state of exoplanet atmospheres. Measuring and understanding the trends within the fundamental properties of exoplanets are at the core of answering these questions. Properties like effective temperature, gravity, mass, radius, and metallicity are key parameters for investigating other worlds. While the transiting and radial velocity planet populations have been investigated via the parameters of their host stars, to date it has been nearly impossible to measure any of these for an exoworld directly from its own data. Major advancements in our understanding have been made not by studying directly imaged exoplanets alone, but by examining their relationship to isolated young brown dwarfs. These substellar objects have parallax measurements along with broad band photometry and spectral coverage from the optical through the mid infrared that has led to breakthroughs in our understanding of cool atmosphere physics. In this talk I will use a population of 152 young brown dwarfs supplemented with outlier populations of extremely cold (Y dwarfs) and low metallicity (subdwarfs) objects with parallaxes to demonstrate how youth, temperature, and gravity alter the observable properties of this analog population to giant exoplanets. Using a library of spectral energy distributions for the brown dwarf population I will show how we have teased out atmosphere parameters of isolated exoplanet equivalents and started to decipher key observables that could point to formation and evolution differences among objects.
Sarah Sadavoy, CfA
Thursday, March 29, 2018
3:45 p.m.
LGRT 1033
Title:
TBA
Abstract:
TBA
Mark Vogelsberger, MIT
Thursday, April 5, 2018
3:45 p.m.
LGRT 1033
Title:
Simulating Galaxy Formation: Illustris, IllustrisTNG and beyond
Abstract:
Cosmological simulations of galaxy formation have evolved significantly over the last years. In my talk I will describe recent efforts to model the large-scale distribution of galaxies with cosmological hydrodynamics simulations. I will focus on the Illustris simulation, and our new simulation campaign, the IllustrisTNG project. After demonstrating the success of these simulations in terms of reproducing an enormous amount of observational data, I will also talk about their limitations and directions for further improvements over the next couple of years.
Regina Jorgenson, Maria Mitchell Association
Thursday, April 12, 2018
3:45 p.m.
LGRT 1033
Title:
TBA
Abstract:
TBA
Susan Kassin, STScl
Thursday, April 19, 2018
3:45 p.m.
LGRT 1033
Title:
TBA
Abstract:
TBA
Antarra Basu-Zych, GSFC/Univ. of Maryland
Thursday, April 26, 2018
3:45 p.m.
LGRT 1033
Title:
TBA
Abstract:
TBA