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IFS Institute for Fundamental Science

Current Seminars

Institute for Fundamental Science

2024-25 Academic Year

Seminars, Colloquia, and Workshops

Organizer and host: Pouya Asadi

Unless otherwise noted, IFS seminars are Mondays at 4:00 p.m. in the IFS Seminar Room, 472 Willamette Hall.

A seminar announcement is distributed via email prior to each one. To add your name to the notification list, please email your request to Claire Staley, cnstaley@uoregon.edu.

To see prior years’ seminars, click here.

RECURRING ZOOM LINK

 

Winter Term 2025

 

Wednesday, January 15  4:00 – 5:00 pm    **SPECIAL DAY**

Probing Dark Matter Microphysics Using Stellar Streams

Speaker: Aditya Parikh (Stony Brook University)

Abstract:

If dark matter has strong self-interactions, future astrophysical and cosmological observations, together with a clearer understanding of baryonic feedback effects, might be used to extract the velocity dependence of the dark matter scattering rate. To interpret such data, we should understand what predictions for this quantity are made by various models of the underlying particle nature of dark matter. In this talk, we systematically compute this function for fermionic dark matter with light bosonic mediators of vector, scalar, axial vector, and pseudoscalar type. We do this by matching to the nonrelativistic effective theory of self-interacting dark matter and then computing the spin-averaged viscosity cross section nonperturbatively by solving the Schrodinger equation, thus accounting for any possible Sommerfeld enhancement of the low-velocity cross section. In the pseudoscalar case, this requires a coupled-channel analysis of different angular momentum modes. We find, contrary to some earlier analyses, that nonrelativistic effects only provide a significant enhancement for the cases of light scalar and vector mediators. Scattering from light pseudoscalar and axial vector mediators is well described by tree-level quantum field theory.

We end by discussing the potential of using stellar streams as detectors of low-mass dark substructure, where self-interactions can have pronounced effects. In particular, we will focus on the cold dark matter case first in an effort to establish a baseline of the features created in stellar streams by low-mass dark substructure. This baseline will in turn set the stage for a more detailed study of the self-interacting dark matter parameter space.

Host: Ben Lillard

 

Monday, January 20 ||  No Seminar – MLK Jr Day

Monday, February 10  4:00 – 5:00 pm    

Using cogsworth to make self-consistent population synthesis & galactic dynamics simulations of observable binary product populations

Speaker: Tom Wagg (University of Washington)

Abstract:

Feedback from massive stars shapes the formation and evolution of galaxies. The majority of these massive stars are found in binaries, yet many parameters within binary stellar evolution remain poorly constrained. One avenue for improving constraints on these parameters is by using positions and kinematics of massive stars. Binary interactions can leave significant imprints on these parameters, ejecting massive stars rapidly from their birth sites. I will present a new code, cogsworth, which combines population synthesis and galactic dynamics self-consistently, providing the theoretical infrastructure necessary to make detailed predictions for the positions and kinematics of many different massive stellar populations.

I will demonstrate how one can use cogsworth to make predictions for a range of observable binary products, from massive runaway stars and X-ray binaries, to supernovae and short gamma-ray bursts. I will show how cogsworth enables you to plot detailed evolution and orbits of specific binaries, track present-day positions of specific subpopulations and convert intrinsic populations to observables in Gaia. I also will share recent predictions I’ve made with cogsworth on how binary interactions can delay and displace supernova feedback in galaxies. This can reduce the efficiency of feedback close to star-forming regions, and potentially drive galactic outflows from low-density environments.

Host: Yvette Cendes

 

Monday, February 17  4:00 – 5:00 pm    

Title TBA

Speaker: Maxx Miller (University of Oregon)

Abstract: TBA

 

Monday, February 24  4:00 – 5:00 pm    

Title TBA

Speaker: Nick Rodd (Lawrence Berkeley National Lab)

Abstract: TBA

Host: Pouya Asadi

 

Monday, March 3  4:00 – 5:00 pm    

Title TBA

Speaker: Gustavo Marques Tavares (University of Utah)

Abstract: TBA

Host: Pouya Asadi

 

Monday, March 10  4:00 – 5:00 pm    

Title TBA

Speaker: Ore Gottlieb (CCA/Columbia)

Abstract: TBA

Host: Ray Frey

 

Monday, March 17  4:00 – 5:00 pm    

Title TBA

Speaker: TBA

Abstract: TBA



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