KICP Seminars & Colloquia, Current and Future
Today's Seminar
Upcoming Seminars

Seminar schedule for Current (Fall 2016) & Future Quarters
September 28, 2016
Astronomy Colloquium
Jacob Bean
University of Chicago
Towards the identification of Earth-like worlds with MAROON-X   [Abstract]
September 30, 2016
Friday noon seminar
Irshad Mohammed
Towards precision cosmology with large scale structures: the halo model and perturbative approaches   [Abstract]
October 5, 2016
Astronomy Colloquium
Dan Fabrycky
University of Chicago
Planets around Binary Stars   [Abstract]
October 7, 2016
Friday noon seminar
Chihway Chang
Preparing for the 21cm future - lessons from the Bleien Galactic Survey project   [Abstract]
October 12, 2016
Wednesday colloquium
Marcelle Soares-Santos
The Dark Energy Survey and Gravitational Waves   [Abstract | PDF | Video]
October 14, 2016
Friday noon seminar
Yuhsin Tsai
University of Maryland
Partially Acoustic Dark Matter, Interacting Dark Radiation, and Large Scale Structure   [Abstract]
October 19, 2016
Astronomy Colloquium
Zhi-Yun Li
Protostellar Disks: Formation and Polarization   [Abstract]
October 21, 2016
Friday noon seminar
Jeffrey P Filippini
University of Illinois, Urbana-Champaign
SPIDER: Exploring the dawn of time from above the clouds   [Abstract]
October 25, 2016
Astronomy Tuesday Seminar
Eve Lee
The Late-Time Formation and Dynamical Signatures of Small Planets   [Abstract]
October 26, 2016
Wednesday colloquium
Ben Farr
Enrico Fermi Institute and KICP
The First Four Months of Gravitational Wave Astronomy   [Abstract]
October 28, 2016
Friday noon seminar
Ian P Stern
University of Florida
ADMX (Axion Dark Matter eXperiment)   [Abstract]
November 1, 2016
Astronomy Tuesday Seminar
Siyao Xu
November 2, 2016
Astronomy Colloquium
Feryal Ozel
Black Hole Physics with the Event Horizon Telescope   [Abstract]
November 4, 2016
Friday noon seminar
Arran Phipps
Stanford University
Dark Matter Radio (Hidden Photons/Axions)   [Abstract]
November 9, 2016
Wednesday colloquium
Surjeet Rajendran
UC Berkeley
New Directions in Dark Matter Detection
November 16, 2016
Astronomy Colloquium
Richard Townsend
The Yin and Yang of Slowly-Pulsating B Stars: Asteroseismology and Angular Momentum Redistribution   [Abstract]
November 22, 2016
Astronomy Tuesday Seminar
Anna Lorraine Rosen
University of California, Santa Cruz
November 30, 2016
Astronomy Colloquium
Konstantin Batygin
Planet Nine from Outer Space   [Abstract]
December 6, 2016
Astronomy Tuesday Seminar
Lucianne Walkowicz
Adler Planetarium
Systematic Serendipity: Novel Discoveries in Astronomical Surveys
KICP Wednesday Colloquia: Unless otherwise noted, all talks are held in ERC 161 at 3:30 PM on Wednesdays. A reception will be held in the ERC 401 following the talk.

  • October 12, 2016 | 3:00 PM | ERC 161
    The Dark Energy Survey and Gravitational Waves
    Marcelle Soares-Santos, Fermilab

    PDF | Video
    In this talk I present recent results of the Dark Energy Survey (DES) searches for optical counterparts to Gravitational Wave (GW) events detected by the LIGO/Virgo Collaboration. Our program achieved greater sensitivity than any other optical facility last year. For the second observing campaign (Fall/2016-Spring/2017) our goals are to either make a detection or establish significant constraints on optical emission from such events. DES is the greatest optical imaging survey yet, aiming at percent-level precision measurements of cosmological parameters from a combination of probes such as type Ia supernovae, galaxy clusters, and weak gravitational lensing. These probes are limited by astrophysical systematics and new independent methods are required in order to beat systematic effects down to sub-percent levels. Standard sirens, events for which distances are determined from their gravitational wave signal, are one possible new method to meet that challenge. Our program will potentially have a great impact in our field by exploring this possibility from the observational perspective. In this talk I will also briefly discuss this exciting prospect for future observing campaigns.
  • October 26, 2016 | 3:30 PM | ERC 161
    The First Four Months of Gravitational Wave Astronomy
    Ben Farr, Enrico Fermi Institute and KICP
    Note: Refreshments served at 4:30 PM, ERC 401

    On September 14, 2015 LIGO made the first direct detection of gravitational waves, marking the beginning of gravitational wave astronomy. The LIGO instruments continued to take data over the next four months, completing their first observing run on January 19, 2016 with 51.5 days of coincident data. I will present results from advanced LIGO's first four months of operation, and what they have taught us thus far.
  • November 9, 2016 | 3:00 PM | ERC 161
    New Directions in Dark Matter Detection
    Surjeet Rajendran, UC Berkeley
    Note: Reception at 4:30 PM in the ERC 401.

KICP Friday noon seminar: Unless otherwise noted, all talks are held in ERC 401 at Noon on Fridays.

  • September 30, 2016 | 12:00 PM | ERC 401
    Towards precision cosmology with large scale structures: the halo model and perturbative approaches
    Irshad Mohammed, Fermilab

    The theoretical modeling of the statistical observables of the large-scale structures of the Universe, like galaxy clustering, weak lensing etc., is necessary in order to derive any constraints on the cosmological parameters. One of the most important ingredients of the theoretical model is the two-point correlation function, or its Fourier transform the matter power spectrum. I will discuss the precision in its calculations based on a modified halo model, and the systematic effects due to the baryonic processes. Further, I will also discuss the covariance matrix of the matter power spectrum and its estimators based on the halo model and the perturbation theory. We find the agreement with the simulations is at a 10% level up to k ∼ 1 h/Mpc. We show that all the connected components are dominated by the large-scale modes (k < 0.1h/Mpc), regardless of the value of the wavevectors of the covariance matrix. Finally, I will provide a prescription for how to evaluate the covariance matrix from small box simulations without the need to simulate large volumes.
  • October 7, 2016 | 12:00 PM | ERC 401
    Preparing for the 21cm future - lessons from the Bleien Galactic Survey project
    Chihway Chang, UofC

    HI intensity mapping is emerging as a new and promising cosmological probe for both the large-scale structure and the early Universe. In preparation for the many large radio projects that are coming online, we launched the Bleien Galactic Survey project as an exercise to test new (and fun) techniques that could develop into useful tools in future surveys. I will first introduce the background science and basic setup of the experiment, and then touch upon two particularly interesting ideas - calibrating the telescope beam using drones, and RFI mitigation with start-of-the-art deep learning algorithms.
  • October 14, 2016 | 12:00 PM | ERC 401
    Partially Acoustic Dark Matter, Interacting Dark Radiation, and Large Scale Structure
    Yuhsin Tsai, University of Maryland

    The standard paradigm of collisionless cold dark matter is in tension with measurements on large scales. In particular, the best fit values of the Hubble rate and the matter density perturbation inferred from the CMB seem inconsistent with the results from direct measurements. In this talk, I will discuss these issues and propose a solution to both problems from a dark sector that contains dark acoustic oscillations with dark fluid. Such a solution can be tested by future experiments designed to probe the CMB and large scale structure.
  • October 21, 2016 | 12:00 PM | ERC 401
    SPIDER: Exploring the dawn of time from above the clouds
    Jeffrey P Filippini, University of Illinois, Urbana-Champaign

    Inflation is thought to have seeded the cosmos with a hum of primordial gravitational waves - unique messengers from the universe's earliest moments. These ripples in spacetime should have left a unique "B-mode" signature on the polarization of the cosmic microwave background. SPIDER is a powerful balloon-borne instrument designed to tease out this polarization pattern in the presence of galactic foregrounds. I will give an update from SPIDER's successful long-duration balloon flight over the Antarctic ice in January 2015, including performance estimates and the current status of the analysis, as well as a status report on payload development for SPIDER's upcoming second flight.
  • October 28, 2016 | 12:00 PM | ERC 401
    ADMX (Axion Dark Matter eXperiment)
    Ian P Stern, University of Florida

    Nearly all astrophysical and cosmological data point convincingly to a large component of cold dark matter (CDM) in the Universe. The axion particle, first theorized as a solution to the strong charge-parity problem of quantum chromodynamics, has been established as a prominent CDM candidate. Cosmic observation and particle physics experiments have bracketed the unknown mass of CDM axions between approximately a μeV and a meV. The Axion Dark Matter eXperiment (ADMX) is a direct-detection CDM axion search which has set limits at the KSVZ coupling of the axion to two photons for axion masses between 1.9 and 3.7 μeV. ADMX has recently begun conducting searches with an upgraded detector, which will allow for detection at even the most pessimistic couplings within this mass range. In order to expand the mass reach of the detector, ADMX is conducting extensive research and development of microwave cavity technology. Status of the experiment, current research, and projected sensitivities will be presented.
  • November 4, 2016 | 12:00 PM | ERC 401
    Dark Matter Radio (Hidden Photons/Axions)
    Arran Phipps, Stanford University

    Determining the composition of dark matter is at the forefront of modern scientific research. There is compelling evidence for the existence of vast quantities of dark matter throughout the universe, however it has so-far eluded all direct detection efforts and its identity remains a mystery. While weakly interacting massive particles (WIMPs) are a favored candidate and have been the primary focus of direct detection for several decades, there has been recent interest in searching for ultra light field dark matter. The Dark Matter Radio is a tunable superconducting high-Q lumped-element resonator (read out with SQUIDs) being built to search for sub-eV hidden photon and axion dark matter. I will discuss the motivation, detection strategy, design, and current status of the DM Radio experiment.



KICP's Thunch: KICP Cosmology Lunch (Thunch) Weekly on Thursdays, Noon, ERC 401A.

Please join us for an informal lunch discussion, led by KICP fellows, of recent news and papers in cosmology. Topics range from experiment and observations to theory in all areas of KICP science. To submit or view papers for this week's Thunch please visit the Thunch website.

Colloquia of the Department of Astronomy & Astrophysics: Unless otherwise noted, all talks are held in ERC 161 at 3:30 PM on Wednesdays. A reception will be held in Hubble Lounge (ERC 501) following the talk.

  • September 28, 2016 | 3:30 PM | ERC 161
    Towards the identification of Earth-like worlds with MAROON-X
    Jacob Bean, University of Chicago

    Exoplanet surveys have recently progressed to the point of discovering small, potentially terrestrial planets orbiting in circumstellar habitable zones. Assessing the true degree of habitability of these worlds requires gaining knowledge of both their bulk and atmospheric properties. In this talk I will present my group's work to make advances on these subjects. I will begin wit an overview of recent results from exoplanet atmosphere observations with an emphasis on results from major program using the Hubble and Spitzer Space Telescopes. I will then summarize the development of MAROON-X, which is a high precision radial velocity spectrograph designed to measure the masses, and thus constrain the densities of potentially Earth-like worlds. I will describe how MAROON-X will be used in conjunction with future facilities like TESS, JWST, and the GMT to make the first credible searches for habitable environments beyond our Solar System.
  • October 5, 2016 | 3:30 PM | ERC 401 (Note new location)
    Planets around Binary Stars
    Dan Fabrycky, University of Chicago

    Planet formation and evolution around single stars seemed hard enough. Now gas giant planets have been found orbiting binary stars, bringing new challenges and opportunities regarding the theory of planet formation and evolution. First we will review the discoveries of a dozen planets by NASA's Kepler mission, using both the transit and the timing methods. These discoveries prove that planets can tiptoe near the instability zone; the specific dynamical arrangements offers clues into migration of planets through gaseous disks. Planets seem to avoid coming near very close binaries, which is a new data point relating to the dynamical history of such binaries. That some planets went unstable is very likely, and we consider the fate of such planets as well as observational signatures.
  • October 19, 2016 | 3:30 PM | ERC 161
    Protostellar Disks: Formation and Polarization
    Zhi-Yun Li, Virginia

    Circumstellar disks play a central role in the formation of both stars and planets, but how they form remains uncertain. Once thought to be a simple consequence of the conservation of angular momentum during the hydrodynamic collapse of molecular cloud cores, disk formation is now known to be complicated by the presence of a dynamically important magnetic field, which can strongly brake the rotation. Indeed, both analytic arguments and numerical simulations have shown that protostellar disk formation is suppressed in the ideal MHD limit for the observed level of cloud core magnetization. In the first part of the talk, I will discuss the physical reason for this so-called "magnetic braking catastrophe" in disk formation, and review possible ways to avert it, including non-ideal MHD effects, misalignment between the magnetic field and rotation axis, and turbulence. In the second part, I will discuss the millimeter polarization recently detected in the disk of the famous young stellar object HL Tau, focusing on possible contribution from scattering by large dust grains. If confirmed, the dust scattering-induced polarization would open a new window on grain growth, the crucial first step toward the formation of planetesimals and eventually planets. The field of disk polarization is poised for rapid growth in the ALMA era.
  • November 2, 2016 | 3:30 PM | ERC 161
    Black Hole Physics with the Event Horizon Telescope
    Feryal Ozel, Arizona
    Note: Refreshments served at 4:30 PM, Astro Lounge

    The Event Horizon Telescope is an experiment that is being performed on a large and ever-increasing array of radio telescopes that span the Earth from Hawaii to Chile and from the South Pole to Arizona. When data will be taken with the full array, it will image the event horizons of the supermassive black hole at the center of our Galaxy, Sagittarius A*, and the black hole at the center of M87, with an unprecedented 10 microarcssecond resolution. This will allow us to take the first ever pictures of black holes at 1.3 and 0.85 mm wavelengths and look for the shadow that is a direct evidence for a black hole predicted by the theory of General Relativity. In addition, the Event Horizon Telescope will also enable us to study the process by which black holes accrete matter and grow in mass. I will discuss the theoretical developments in simulating the properties of the black hole accretion flows and their expected images using state-of-the-art algorithms and high performance computing. Interpreting the upcoming observations within this theoretical framework will open new horizons in black hole astrophysics.
  • November 16, 2016 | 3:30 PM | ERC 161
    The Yin and Yang of Slowly-Pulsating B Stars: Asteroseismology and Angular Momentum Redistribution
    Richard Townsend, Wisconsin
    Note: Refreshments served at 4:30 PM, Astro Lounge

    During their main-sequence evolution, almost all B-type stars will pass through a phase where they are unstable toward oscillation in one or more global internal gravity waves ('g modes'). The g modes, driven by iron and nickel opacity in the stars' outer envelopes, generate surface temperature and velocity changes with periodicities on the order of days. In the 'Yin' part of my talk, I'll discuss how time-series spectroscopy and photometry of these `slowly-pulsating B' (SPB) stars can be leveraged into asteroseismology --- probing the stars' interiors by careful analysis of their oscillation spectra. I'll highlight in particular how the Kepler mission, together with the MESA stellar evolution code and my GYRE stellar oscillation code, has allowed novel constraints to be established on the internal rotation and mixing physics of SPB stars. I'll then pivot to the 'Yang' part of my talk. Although we typically regard stellar oscillations as passive tracers of stellar structure, they can also modify this structure. I'll present recent work by my group exploring angular momentum redistribution by g modes. Modeling this process in SPB stars, we find that significant modification of internal rotation profiles can occur on timescales as short as centuries. This suggests that the g modes can impact the stars' life trajectories, a possibility that's been hitherto ignored in stellar evolution calculations.
  • November 30, 2016 | 3:30 PM | ERC 161
    Planet Nine from Outer Space
    Konstantin Batygin, Caltech
    Note: Refreshments served at 4:30 PM, Astro Lounge

    At the outskirts of the solar system, beyond the orbit of Neptune, liesan expansive field of icy debris known as the Kuiper belt. The orbits ofthe individual asteroid-like bodies within the Kuiper belt trace out highly elongated elliptical paths, and require hundreds to thousands of years to complete a single revolution around the Sun. Although the majority of the Kuiper belt’s dynamical structure can be understood within the framework of the known eight-planet solar system, bodies with orbitalperiods longer than about 4,000 years exhibit a peculiar orbital alignment that eludes explanation. What sculpts this alignment and how is it preserved? In this talk, I will argue that the observed clustering of Kuiperbelt orbits can be maintained by a distant, eccentric, Neptune-like planet, whose orbit lies in approximately the same plane as those of the distant Kuiper belt objects, but is anti-aligned with respect to those of the small bodies. In addition to accounting for the observed grouping of orbits, the existence of such a planet naturally explains other, seemingly unrelated dynamical features of the solar system.


  • October 25, 2016 | 12:00 PM | ERC 576
    The Late-Time Formation and Dynamical Signatures of Small Planets
    Eve Lee, UCBerkeley

    The Kepler mission has established that approximately half of all Sun-like stars harbor planets. Of these, close-in super-Earths are the most common. Understanding the origin of super-Earths can lend us insight into the default pathway of planet formation. The riddle posed by super-Earths is that they are not Jupiters: their core masses are large enough to trigger runaway gas accretion, yet somehow super-Earths accreted atmospheres that weigh only a few percent of their total mass. I will show that this puzzle is solved if super-Earths formed late, in the inner cavities of transitional disks. Super-puffs present the inverse problem of being too voluminous for their small masses. I will show that super-puffs most easily acquire their thick atmospheres as dust-free, rapidly cooling worlds outside 1 AU, and then migrate in just after super-Earths appear. Small planets may remain ubiquitous out to large orbital distances. I will demonstrate that the variety of debris disk morphologies revealed by scattered light images can be explained by viewing an eccentric disk, secularly forced by a planet of just a few Earth masses, from different observing angles. The farthest reaches of planetary systems may be perturbed by eccentric super-Earths.
  • November 1, 2016 | 12:00 PM | ERC 576
    Siyao Xu, KIAA/UNLV
  • November 22, 2016 | 12:00 PM | ERC 576
    Anna Lorraine Rosen, University of California, Santa Cruz
  • December 6, 2016 | 12:00 PM | ERC 576
    Systematic Serendipity: Novel Discoveries in Astronomical Surveys
    Lucianne Walkowicz, Adler Planetarium