KICP Seminars & Colloquia, Winter 2018

Seminar schedule for Winter 2018
January 10, 2018
Wednesday colloquium
Erik P. Verlinde
University of Amsterdam
From Emergent Gravity to Dark Energy and Dark Matter   [Abstract | Video]
January 12, 2018
Friday noon seminar
Patricia Larsen
Argonne National Laboratory
Topics in weak lensing   [Abstract]
January 16, 2018
Astronomy Tuesday Seminar
Rachael Roettenbacher
Stockholm University
Surveying Spotted Stars with Photometric, Spectroscopic, and Interferometric Observations   [Abstract]
January 17, 2018
Astronomy Colloquium
Maggie Turnbull
SETI
WFIRST: Where Things Stand with the First Exoplanet Direct Imaging Flight Mission   [Abstract]
January 19, 2018
Friday noon seminar
Jessica M Turner
Fermi National Accelerator Laboratory
Discussion on old and new mechanisms of leptogenesis   [Abstract]
January 24, 2018
Wednesday colloquium
Laura Trouille
The Adler Planetarium and Northwestern University
Citizen Science Frontiers: Efficiency, Engagement, and Serendipitous Discovery with Human-Machine Systems   [Abstract]
January 26, 2018
Friday noon seminar
Yao-Yuan Mao
University of Pittsburgh
Mass' not the only thing: Secondary effects in the galaxy-halo connection
January 31, 2018
Astronomy Colloquium
Ellen Zweibel
University of Wisconsin-Madison
TBA
February 2, 2018
Friday noon seminar
Daniel Jacobs
Arizona State University
High redshift 21cm intensity mapping Past, Present, and Future   [Abstract]
February 7, 2018
Wednesday colloquium
Peter Adshead
University of Illinois at Urbana-Champaign
TBA
February 9, 2018
Friday noon seminar
Francisco Villaescusa-Navarro
Center for Computational Astrophysics
The impact of massive neutrinos on cosmological observables
February 14, 2018
Astronomy Colloquium
Tim Heckman
Johns Hopkins University
TBA
February 28, 2018
Astronomy Colloquium
Enrico Ramirez-Ruiz
University of California, Santa Cruz
TBA
March 7, 2018
Astronomy Colloquium
Bekki Dawson
Pennsylvania State University
TBA
March 14, 2018
Wednesday colloquium
Katherine Freese
University of Michigan
Dark Matter in the Universe   [Abstract]
 
WEDNESDAY COLLOQUIA

  • January 10, 2018 | 3:30 PM | ERC 161
    From Emergent Gravity to Dark Energy and Dark Matter
    Erik P. Verlinde, University of Amsterdam

    Video
    The observed deviations from the laws of gravity of Newton and Einstein in galaxies and clusters can logically speaking be either due to unseen dark matter or due to a change in the way gravity works. Until recently there was little reason to doubt that general relativity correctly describes gravity in these circumstances. In the past few years insights from black hole physics and string theory have lead to a new theoretical framework in which the gravitational laws are derived an underlying microscopic quantum description of spacetime. An essential ingredient in the derivation of the Einstein equations is that the quantum entanglement of the vacuum obeys an area law, a condition that is known to hold in Anti-de Sitter space. In a Universe that is dominated by positive dark energy, like de Sitter space, the microscopic entanglement entropy contains, in addition to the area law, a volume law contribution whose total contribution equals the Bekenstein-Hawking entropy associated with the cosmological horizon. We will argue that this extra volume law contribution leads to modifications in the emergent laws of gravity, and provide evidence for the fact that these modifications explain the observed phenomena in galaxies and clusters currently attributed to dark matter. We end with a discussion of the possible implications for early cosmology, the CMB and structure formation.
  • January 24, 2018 | 3:30 PM | ERC 161
    Citizen Science Frontiers: Efficiency, Engagement, and Serendipitous Discovery with Human-Machine Systems
    Laura Trouille, The Adler Planetarium and Northwestern University
    Note: Reception at 4:30 PM in the ERC 401.

    The Zooniverse is the world's largest and most successful scientific crowdsourcing platform, engaging more than 1.6 million volunteers in tasks including classifying galaxies, discovering planets, transcribing artist’s notebooks, and tracking resistance to antibiotics. Processing our increasingly large datasets poses a bottleneck for producing real scientific outcomes. Citizen science – engaging the public in research – provides a solution, particularly when coupled with machine learning algorithms and sophisticated task allocation. Faced with a rapidly growing demand for citizen science projects, Zooniverse launched its ‘Project Builder’ which allows you, the researcher, to build your own project in-house for free using the Zooniverse infrastructure and tools. In this talk I will discuss the frontiers of citizen science, including Zooniverse innovations in human-machine integration coupled with community engagement -- and the related open questions. I will also provide a brief tutorial on building your own crowdsourcing project.
  • February 7, 2018 | 3:30 PM | ERC 161
    TBA
    Peter Adshead, University of Illinois at Urbana-Champaign
  • March 14, 2018 | 3:00 PM | ERC 161
    Dark Matter in the Universe
    Katherine Freese, University of Michigan
    Note: Reception at 4:30 PM in the ERC 401.

    “What is the Universe made of?” This question is the longest outstanding problem in all of modern physics, and it is one of the most important research topics in cosmology and particle physics today. The bulk of the mass in the Universe is thought to consist of a new kind of dark matter particle, and the hunt for its discovery in on. I'll start by discussing the evidence for the existence of dark matter in galaxies, and then show how it fits into a big picture of the Universe containing 5% atoms, 25% dark matter, and 70% dark energy. Neutrinos only constitute ½% of the content of the Universe, but much can be learned about neutrino properties from cosmological data. Leading candidates for the dark matter are Weakly Interacting Massive Particles (WIMPs), axions, and sterile neutrinos. WIMPs are a generic class of particles that are electrically neutral and do not participate in strong interactions, yet have weak-scale interactions with ordinary matter. There are multiple approaches to experimental searches for WIMPS: at the Large Hadron Collider at CERN in Geneva; in underground laboratory experiments; with astrophysical searches for dark matter annihilation products, and upcoming searches with the James Webb Space Telescope for Dark Stars, early stars powered by WIMP annihilation. Current results are puzzling and the hints of detection will be tested soon. At the end of the talk I'll briefly turn to dark energy and its effect on the fate of the Universe.

 
FRIDAY NOON SEMINARS

  • January 12, 2018 | 12:00 PM | ERC 401
    Topics in weak lensing
    Patricia Larsen, Argonne National Laboratory

    Gravitational weak lensing has emerged in recent years as a powerful probe of cosmology, giving important constraints on both dark and luminous matter. This has led to a number of ambitious future surveys, which promise to revolutionise the field if theoretical challenges can be met. In this talk I will discuss some of my recent work in the field of weak lensing, spanning a range of topics including combined probe analysis, intrinsic alignment contamination and delensing.
  • January 19, 2018 | 12:00 PM | ERC 401
    Discussion on old and new mechanisms of leptogenesis
    Jessica M Turner, Fermi National Accelerator Laboratory

    In the first half of the talk, I will present preliminary results which indicate the scale of thermal leptogenesis may be several orders of magnitude lower than previously thought. In the second half of this talk I will present a mechanism of leptogenesis which is based on the vacuum CP-violating phase transition. This approach differs from classical thermal leptogenesis as a specific seesaw model, and its UV completion, need not be specified. The lepton asymmetry is generated via the dynamically realised coupling of the Weinberg operator during the phase transition. This mechanism provides strong connections with low-energy neutrino experiments.
  • January 26, 2018 | 12:00 PM | ERC 401
    Mass' not the only thing: Secondary effects in the galaxy-halo connection
    Yao-Yuan Mao, University of Pittsburgh
  • February 2, 2018 | 12:00 PM | ERC 401
    High redshift 21cm intensity mapping Past, Present, and Future
    Daniel Jacobs, Arizona State University

    The redshifted 21 cm line from neutral hydrogen provides a direct, cosmological scale, probe of the epochs of reionization and heating. In the past decade, multiple experimental arrays have worked towards detection and characterization of this spectral line signal at redshifts 6 and higher. HERA is a second generation instrument probing 21cm emission and absorption at redshifts from 6 to 20. The use of large static dishes provides sensitivity which is predicted to be roughly an order of magnitude larger than first generation experiments while advances in instrumentation and technique aim for reduced foreground contamination. The raw sensitivity provided by dishes is high enough that forecasts of astrophysical parameter constraint precision is limited mainly by model uncertainty not sensitivity, and that for the first time direct imaging of features is theoretically possible. HERA is proceeding with construction while observing in parallel with new dishes being added as they become available. The 2017-2018 observing season with 40 dishes is forecasted to have roughly double the sensitivity of previous experiments. Here we report the ongoing commissioning of this array and present early results of experiments in calibration and imaging.
  • February 9, 2018 | 12:00 PM | ERC 401
    The impact of massive neutrinos on cosmological observables
    Francisco Villaescusa-Navarro, Center for Computational Astrophysics

 
ASTRONOMY COLLOQUIA

  • January 17, 2018 | 3:30 PM | ERC 161
    WFIRST: Where Things Stand with the First Exoplanet Direct Imaging Flight Mission
    Maggie Turnbull, SETI

    The WFIRST mission will be the first demonstration of exoplanet coronagraphy in space, and is intended to demonstrate several key technologies that are on the critical path to larger missions that will eventually find and spectrally characterize planets that could be habitable to life as we know it. WFIRST entered Phase A in January of 2016, and is expected to enter Phase B in April of this year. This talk will describe the entertaining story of how this mission came to be, where things currently stand in terms of predicted imaging performance, the potential for a starshade rendezvous mission, and what to expect for guest observer opportunities. I'll also describe how the two coronagraph science teams are working to maximize the scientific output of what is categorized as a "technology demonstration" instrument. Finally, I'll offer some of my personal take-aways from the experience of watching such a large and challenging mission come together.
  • January 31, 2018 | 3:30 PM | ERC 161
    TBA
    Ellen Zweibel, University of Wisconsin-Madison
    Note: Refreshments served at 4:30 PM, Hubble Lounge
  • February 14, 2018 | 3:30 PM | ERC 161
    TBA
    Tim Heckman, Johns Hopkins University
    Note: Refreshments served at 4:30 PM, Hubble Lounge
  • February 28, 2018 | 3:30 PM | ERC 161
    TBA
    Enrico Ramirez-Ruiz, University of California, Santa Cruz
    Note: Refreshments served at 4:30 PM, Hubble Lounge
  • March 7, 2018 | 3:30 PM | ERC 161
    TBA
    Bekki Dawson, Pennsylvania State University
    Note: Refreshments served at 4:30 PM, Hubble Lounge

 
ASTRONOMY TUESDAY SEMINARS

  • January 16, 2018 | 12:00 PM | ERC 576
    Surveying Spotted Stars with Photometric, Spectroscopic, and Interferometric Observations
    Rachael Roettenbacher, Stockholm University

    For stars with convective outer layers, stellar magnetism manifests as dark starspots -- localized regions of stifled convection. Starspots affect measurements of fundamental stellar parameters, including temperature and radius, which lead to inaccurate estimates of age and mass. Additionally, starspots have been shown to mimic and obscure detections of planets. By imaging stellar surfaces, we begin to disentangle the signatures of stellar magnetism. The imaging efforts discussed here feature aperture synthesis imaging using interferometric data collected with the Michigan Infrared Combiner (MIRC) at Georgia State University's Center for High Angular Resolution Astronomy (CHARA) Array with sub-milliarcsecond resolution. We characterize active RS CVn binary systems and detect magnetic structures across the surface of the giant primary stars. We compare the results to simultaneous Doppler and light curve inversion imaging. The observed global regions of suppressed convection likely affect stellar parameter estimates by altering the structure of the photosphere. Extensions of this study will survey spotted stars in order to understand how stellar magnetism affects stellar parameters, impacts the evidence of companions and their characterization, accounts for long-term changes in the flux of active stars, and differs from the Sun for stars with large convective envelopes.