2020
Open group seminar: Allison Strom (Carnegie Observatories)
3:30–4:30 pm ERC 419
“Rethinking metallicity: the quest to measure the chemistry of distant galaxies”
KICP seminar: Dhanesh Krishnarao (University of Wisconsin-Madison)
12:00–1:00 pm ERC 401
“The Inner Milky Way: Our New Closest LI(N)ER”
A&A Colloquium - Marco Velli (UCLA)
3:30–4:30 pm ERC 161
“Parker Solar Probe: Understanding Coronal heating and Solar Wind Acceleration”
The magnetic field is fundamental to solar activity and shapes the inter-planetary environment, as shown by the full three dimensional monitoring of the heliosphere provided by measurements from many past and present interplanetary and remote sensing spacecraft. Magnetic fields are also the source for coronal heating and the very existence of the solar wind; produced by the sun’s dynamo and emerging into the corona, magnetic fields become a conduit for waves, act to store energy, and then propel plasma into the Heliosphere in the form of Coronal Mass Ejections (CMEs). Magnetic fields are also at the heart of the generation and acceleration of Solar Energetic Particle (SEPs) that modify the space weather environment of the Earth and other planets.
Parker Solar Probe (PSP) was launched in August 2018 to carry out the first in situ exploration of the outer solar corona and inner Heliosphere. Direct measurements of the plasma in the closest atmosphere of our star should lead to a new understanding of the questions of coronal heating, solar wind acceleration, and the generation, acceleration and propagation of SEPs.
In this lecture I will start with an introduction to our present knowledge of the magnetized solar corona and wind before describing the PSP scientific objectives, orbit, and instrument suites, and showing results from the first three orbits. Emphasis will be on how PSP will confirm or falsify present wind models as well as the potential new discoveries stemming from the first exploration of the space inside the orbit of Mercury. I will also discuss how synergies with Solar Orbiter might lead us to accurately understand the state of the solar wind all the way from the corona into interplanetary space, a stepping stone for understanding the dynamics of active magnetized plasmas throughout the universe.
Special A&A Colloquium: Azadeh Maleknejad (Max Planck Institute for Astrophysics)
12:00–1:00 pm ERC 576
A new paradigm for particle cosmology
Modern cosmology has been remarkably successful in describing the Universe from a second after the Big Bang until today. However, our current understanding of the cosmos before that time is less precise. Moreover, cosmology profoundly involves particle theory beyond the Standard Model to explain its long-standing puzzles: the origin of the observed matter asymmetry, particle nature of dark matter, and cosmic inflation. In this colloquium, I will explain that relic axion-gauge fields in fractions of a second after the Big Bang can relate and explain these seemingly unrelated puzzles in early and late cosmology. As a smoking gun, such relics would provide a new window into the early Universe through primordial gravitational waves. Therefore, they are testable by future CMB missions.
KICP seminar: Carmen Carmona Benitez (Pennsylvania State University)
12:00–1:00 pm ERC 401
“Near Future of Dark Matter Searches: Go Big, or Go Low”
KICP Colloquium: James Bock (California Institute of Technology)
3:30–4:30 pm ERC 161
“SPHEREx: An All-sky Infrared Spectral Survey Explorer Satellite”
Chalk Talk: Congyao Zhang (UChicago) & Francisco Javier Sanchez Lopez (Fermilab)
12:00–1:00 pm ERC 501
Congyao Zhang (UChicago)
“Formation of Galaxy Clusters – from the Core to the Outskirts”
&
Francisco Javier Sanchez Lopez (Fermilab)
“Olber’s paradox revisited: effects of overlapping sources on cosmic shear estimation”
KICP seminar: Tien-Tien Yu (University of Oregon)
12:00–1:00 pm ERC 401
“A New Look at the Migdal Effect”
College Break
All day
A&A Colloquium - Lorenzo Sironi (Columbia)
3:30–4:30 pm ERC 161
Fast and furious: magnetic reconnection in relativistic jets and black hole coronae
Relativistic jets of blazars and magnetized coronae of low-luminosity accretion flows, like Sgr A* at our Galactic Center, routinely display fast and bright flares of high-energy emission. Yet, the “engine” responsible for accelerating the emitting particles to ultra-relativistic energies is still unknown. With fully-kinetic particle-in-cell (PIC) simulations, we argue that magnetic reconnection — a process by which magnetic field lines of opposite polarity annihilate, releasing their energy to the particles — can satisfy all the basic conditions for the emission. In blazar jets, we show that reconnection can naturally explain the puzzling ultra-fast bright flares observed at GeV and TeV energies, whose duration can be even shorter than the light-travel time across the black hole that powers the jet. In low-luminosity accretion flows like Sgr A*, we show that reconnection — potentially seeded by turbulence — can power both thermal and non-thermal emission, and we produce physically-grounded synthetic images and spectra to be compared with infrared and X-ray observations and with the upcoming results of the Event Horizon Telescope.