Events at Physics
Events During the Week of June 26th through July 3rd, 2022
Monday, June 27th, 2022
- Thesis Defense
- Extracting cosmological information from the sky, from the cosmic microwave background to intensity mapping with neutral hydrogen.
- Time: 10:00 am
- Place: Sterling B343 and
- Speaker: Anh Phan , Physics PhD Graduate Student
- Abstract: I will introduce several methods to extract cosmological information from observations of the sky, from the cosmic microwave background (CMB) to hydrogen line intensity mapping. Starting with the first light, the CMB, a cosmological Boltzmann code is presented to calculate the CMB power spectra from different theoretical models, for a flat $(\Omega_k = 0)$ cosmology. It can rapidly compute the CMB power spectrum accurately up to high multipoles. After reviewing the chronological evolution of the Universe, I will then introduce the basic ideas of intensity mapping of neutral hydrogen after recombination, which tells us about structure formation. I will present the first results from the Tianlai Dish interferometer array, which is a new instrument specifically designed and constructed for hydrogen intensity mapping between redshift $z=0$ and $z=2.55$. The array is still in its infancy, and a thorough understanding of the instrument through simulation, calibration, noise analysis is described. An eigen-decomposition method to remove the Sun signal from the timestream data of radio interferometers is discussed in detail. It is applied to Tianlai data, which helps the instrument collect usable data during the daytime. Finally, a machine learning method is presented that maximizes the cross-correlation between hydrogen intensity maps and galaxy redshift surveys as a tool for detecting the hydrogen signal in the presence of bright foregrounds.
- Host: Peter Timbie
Tuesday, June 28th, 2022
- Network in Neutrinos, Nuclear Astrophysics, and Symmetries (N3AS) Seminar
- Collective flavor evolution, collisions, and advection in core-collapse supernovae: The full solution
- Time: 2:00 pm
- Place: Join Zoom Meeting
- Speaker: Shashank Shalgar , Niels Bohr Institute
- Abstract: The effect of collective flavor evolution in the presence of collisions and advection in core-collapse supernovae has been sought after for a while now. I will present the first numerical solution for this problem in the two flavor approximation in spherical geometry. The result is a quasi-steady state configuration which shows some interesting features. Due to the effect of collective flavor evolution, the decoupling radii for each neutrino species are modified, and I will discuss the implications of this. I will also discuss the presence of fast and slow flavor evolution in the vicinity of the neutrino decoupling region.
- Host: Baha Balantekin
Wednesday, June 29th, 2022
- Physics Summer Fun
- Weekly Recess
- Time: 12:30 pm
- Place: Bascom Hill or 5310 Chamberlin Hall
- Speaker: Sharon Kahn
- Abstract: We hope you’ll take a 20-30 minute break on (some/all) Wednesdays this summer (12:30-1pm) to come play together! For nice days, we’ve arranged to borrow some lawn games from the L&S dean’s office and will likely bring along a frisbee and/or a hackeysack, too. Meet us on Bascom Hill (between Birge/South Hall).
In case of rain, we’ll meet indoors (5310 CH) for board games. Feel free to come play or just hang out!
Thursday, June 30th, 2022
- No events scheduled
Friday, July 1st, 2022
- No events scheduled