Recovering the Density Fields inside Quasar Proximity Zones at z~6"
The matter density field at z~6 is very challenging to probe. One of the traditional methods that work successfully at lower redshift is the Lyman-alpha forest in quasar spectra. However, at z~6, the residual neutral hydrogen usually creates saturated absorption, thus much of the information about gas...
Emerging from a big bang in which gravity is strongly coupled and quantum fluctuations of stress-energy and spacetime are both large, the natural expectation is that the total entropy should be nearly maximal and equally distributed among both stress-energy and gravitational degrees of freedom. However, the observed entropy distribution on the last scattering surface is puzzlingly different, as Penrose has emphasized. In this talk, I will introduce the cosmological entropy problem and discuss our recent proposal to evade... Read more about ITC Colloquium - Anna Ijjas
Relativistic cosmic-rays created by stellar and black hole feedback may play an important role in many aspects of structure formation. Cosmic-rays can drive outflows from star forming galaxies and heat diffuse gas in the circumgalactic and intergalactic medium. In this talk I will describe some of the possible impacts of cosmic-rays on galaxy formation, observational probes of their impact, and the theoretical uncertainities in our understanding of the role of cosmic rays in structure...
"Microphysical Insights into Protoplanetary Disks and Exoplanet Atmospheres"
Abstract: A fundamental understanding of planetary histories and characteristics requires an empirical connection between planet formation and evolved planets—a long-sought goal of astrophysics. This connection is now increasingly possible due to simultaneous revolutions in the observations of protoplanetary disks and exoplanet atmospheres. A key step towards relating these observations of different evolutionary stages is to characterize the composition of material in protoplanetary disks and relate these... Read more about ITC Colloquium - Diana Powell (ITC)
"Interactions between black holes, stars, and galaxies"
A physical understanding of the high energy interactions between black holes and stars, coupled with the context of their galactic birthplaces, allows us to use these systems as tools to better understand black holes at all masses, the lives and deaths of stars, and the dynamical mechanisms operating in galaxies. In this talk, I will discuss one particular interaction: the tidal disruption of a star by a supermassive black hole. I will present a library of tidal disruption event simulations and will show that it can be reduced to... Read more about ITC Colloquium - Jamie Law-Smith (ITC)
"Promises and puzzles in binary evolution" Binary stars are foundational to modern astrophysics. They underpin precision measurements of stellar structure, age, and composition; they provide the most stringent tests of general relativity, they make possible the study of faint and rare objects such as black holes and neutron stars, and they are the progenitors of gravitational wave sources. The components of binaries often interact, dramatically changing their evolution and giving rise to a spectacular zoo of astrophysical phenomenology. Large-scale stellar surveys such as Gaia, TESS... Read more about ITC Colloquium - Kareem El-Badry (Harvard)
Connecting Cosmic Gas Flows and Metal Enrichment to Supermassive Black Hole Growth in Galactic Evolution"
In this talk, I will discuss the impact of supermassive black hole (SMBH) feedback on the gas phase evolution of Milky Way-mass (MW-mass) galaxies. Both my simulation suites were created with the N-body+Smoothed particle hydrodynamics code, ChaNGa, and include a...
"Centihertz gravitational-wave astronomy: from hierarchical black-hole triples to ultra-compact white-dwarf binaries"
Future space-borne gravitational-wave (GW) observatories are sensitive to a rich array of astrophysical systems in the centihertz band. Here we focus on two science cases specifically. The first is hierarchical black-hole (BH) triple systems in galactic nuclei. Such a system consists of a stellar-mass inner binary orbiting around a supermassive BH (SMBH). We show that the orbital angular momentum (AM) of the inner binary will precess around the outer orbital... Read more about ITC Colloquium - Hang Yu (Caltech)