Colloquia
Colloquia: Astronomy & Astrophysics colloquia and KICP colloquia - Usually Wednesdays, 3:30 PM, ERC 161, unless otherwise specified. Reception starts at 4:30 PM in Hubble Lounge (Astronomy & Astrophysics colloquia) and ERC 401 (KICP colloquia). Persons with a disability who believe they may need assistance, please call the departmental secretary in advance at 773-702-8203 or email deptsecoddjob.uchicago.edu.

Current & Future Colloquia
DateTalk TitleSpeaker
February 20, 2019
KICP Colloquium
Constraints on Quantum GravityHirosi Ooguri, Caltech & Kavli IPMU
February 27, 2019
Astronomy Colloquium
TBAMansi Kasliwal, Caltech
March 6, 2019
KICP Colloquium
Direct-Detection of Sub-GeV Dark Matter: A New FrontierRouven Essig, Stony Brook University
March 13, 2019
Astronomy Colloquium
TBAMark Vogelsberger, MIT

Past Colloquia
DateTalk TitleSpeaker
February 13, 2019
Astronomy Colloquium
Extreme AstrophysicsRoger Blandford, Stanford University
February 6, 2019
KICP Colloquium
The Planck last releaseJean-Loup Puget, IAS Université Paris-sud
January 30, 2019 cancelled
Astronomy Colloquium
Infrared Spectroscopy of Stars and PlanetsIan Crossfield, MIT
January 23, 2019
KICP Colloquium
A New Frontier in the Search for Dark MatterGordan Krnjaic, Fermilab
January 16, 2019
Astronomy Colloquium
Cosmic ReionizationNick Gnedin, University of Chicago/Fermilab
January 9, 2019
KICP Colloquium
How many numbers does it take to determine our Universe?Michael Turner, KICP

How many numbers does it take to determine our Universe?
January 9, 2019 | ERC 161 | 3:30 PM | KICP Colloquium
Click on the image to enlarge
Michael Turner, KICP

Video
Since 2013, the Planck Surveyor team has made a good case that it takes six numbers to describe the whole Universe (fewer than the ten digits in a phone number), based upon their all-sky map of the CMB. Others have different opinions: zero, one, two, six (a different), and nine to describe our Universe. As I will discuss, the choice of numbers reveals much about what we know and our aspirations, as well as how we think about the Universe. After exploring the landscape, I will advocate for zero numbers and discuss the path and strategy to get there.

Cosmic Reionization
January 16, 2019 | ERC 161 | 3:30 PM | Host: Hsiao-Wen Chen | Astronomy Colloquium
Click on the image to enlarge
Nick Gnedin, University of Chicago/Fermilab

Cosmic reionization - ionization of the bulk of cosmic gas by ultraviolet radiation from first galaxies and quasars - is the least explored epoch in cosmic history. While significant progress has been made recently with the HST Frontier Fields program, the major breakthrough is still in the future, but not a distant one. The launch of JWST will start a revolution in studies of cosmic reionization, and other advanced observational probes will follow soon.

As observers are preparing for the flood of new data, theorists are currently busy revamping their tools to stay on par with future observations. This fortunate match between theory and observations will lead to a major breakthrough in this last cosmic frontier.

A New Frontier in the Search for Dark Matter
January 23, 2019 | ERC 161 | 3:30 PM | KICP Colloquium
Gordan Krnjaic, Fermilab

Video
The gravitational evidence for the existence of dark matter is overwhelming; observations of galactic rotation curves, the CMB power spectrum, and light element abundances independently suggest that over 80% of all matter is "dark" and beyond the scope of the Standard Model. However, its particle nature is currently unknown, so discovering its potential non-gravitational interactions is a major priority in fundamental physics. In this talk, I will survey the landscape of light dark matter theories and and introduce an emerging field of fixed-target experiments that are poised to cover hitherto unexplored dark matter candidates with MeV-GeV masses. These new techniques involve direct dark matter production with proton, electron, and *muon* beams at various facilities including Fermilab, CERN, SLAC, and JLab. Exploring this mass range is essential for fully testing a broad, predictive class of theories in which dark matter abundance arises from dark-visible interactions in thermal equilibrium in the early universe.

Infrared Spectroscopy of Stars and Planets
January 30, 2019 cancelled | ERC 161 | 3:30 PM | Host: Jacob L. Bean | Astronomy Colloquium
Click on the image to enlarge
Ian Crossfield, MIT

CANCELLED

Extrasolar planets and cool stars emit most of their light beyond the range of standard optical observations. These objects are often best studied using infrared spectroscopy. I will present recent results from my group on two topics: space-based IR spectroscopy of exoplanet atmospheres, and ground-based, high-resolution spectroscopy of both planets and stars. I will also conclude with a brief discussing of how future IR-optimized observatories will also enable exciting new science in these areas.

The Planck last release
February 6, 2019 | ERC 161 | 3:30 PM | KICP Colloquium
Jean-Loup Puget, IAS Université Paris-sud

Video
The Planck High frequency maps improvements will be described together with some of their associated cosmology results. Implications for future experiments will also be discussed.

Extreme Astrophysics
February 13, 2019 | ERC 161 | 3:30 PM | Astronomy Colloquium
Roger Blandford, Stanford University

The electromagnetic spectrum has been opened up from meter radio waves to 100 TeV photons and augmented with 10 - 300 Hz gravitational wave, MeV - PeV neutrinos and MeV - ZeV (160 Joule) cosmic ray messages. Consequently, there is a high rate of discovery and understanding of phenomena whose explanation invokes accepted physics - classical (including general relativity), atomic, nuclear and particle (including QED) processes - in extreme environments. The richness of the discovery space can be epitomized by describing some new observations and ideas pertaining to relativistic jets formed by massive spinning black holes, Ultra High Energy Cosmic Rays accelerated by strong shock waves surrounding rich clusters of galaxies and Fast Radio Bursts, generated by neutron stars with 100 GT magnetic fields.

Constraints on Quantum Gravity
February 20, 2019 | ERC 161 | 3:30 PM | KICP Colloquium
Hirosi Ooguri, Caltech & Kavli IPMU

Superstring theory is our best candidate for the ultimate unification of general relativity and quantum mechanics. Although predictions of the theory are typically at extremely high energy and out of reach of current experiments and observations, several non-trivial constraints on its low energy effective theory have been found. Because of the unusual ultraviolet behavior of gravitational theory, the standard argument for separation of scales may not work for gravity, leading to robust low energy predictions of consistency requirements at high energy. In this colloquium talk, I will start by explaining why the unification of general relativity and quantum mechanics has been difficult. After introducing the holographic principle as our guide to the unification, I will discuss its use in finding constraints on symmetry in quantum gravity. I will also discuss other conjectures on low energy effective theories, collectively called swampland conditions, with various levels of rigors. They include the weak gravity conjecture, which gives a lower bound on Coulomb-type forces relative to the gravitational force, and the distance conjecture, which is about structure of the space of scalar fields. I will discuss consequences of the conjectures.

Reception at 4:30 PM in the ERC 401.

TBA
February 27, 2019 | ERC 161 | 3:30 PM | Astronomy Colloquium
Mansi Kasliwal, Caltech

Refreshments served at 4:45 PM, Hubble Lounge

Direct-Detection of Sub-GeV Dark Matter: A New Frontier
March 6, 2019 | ERC 161 | 3:30 PM | KICP Colloquium
Rouven Essig, Stony Brook University

Reception at 4:30 PM in the ERC 401.

TBA
March 13, 2019 | ERC 161 | 3:30 PM | Astronomy Colloquium
Mark Vogelsberger, MIT

Refreshments served at 4:45 PM, Hubble Lounge