Stars, Planets, and ISM Seminar
Nov
19
2025
Nov
19
2025
Description
Yuanhong Qu, UNLV
Magnetar Crust Quake Triggered Fast Radio Bursts
In this talk, I will present my work on the trigger mechanisms, radiation processes, and non-linear scattering propagation effect of fast radio bursts (FRBs). I will begin by discussing generic observational constraints on the intrinsic radiation mechanisms of FRBs and argue that repeating FRBs most likely originate within the magnetar magnetosphere. I will show that magnetar crust quakes, as the trigger mechanism, play a crucial role in exciting various wave modes in the magnetosphere. These waves couple directly to fast magnetosonic and Alfvén waves in the magnetosphere, both typically in the kilohertz band and excited by crust quakes. I will present the first 3D elasto-dynamic simulations of the entire magnetar crust, demonstrating that both fast magnetosonic and Alfvén waves can be generated with comparable energy contributions. Next, I will show that FRBs are likely produced via coherent inverse Compton scattering (ICS) of low-frequency fast magnetosonic waves by relativistic charged bunches at distances of a few hundred magnetar radii. I will also discuss the ICS model's implications, including the high degrees of linear and circular polarization and the narrow spectra observed in many repeating FRBs. Finally, I will discuss the non-linear scattering of FRBs and demonstrate that in the open field line region, large-amplitude FRBs can freely escape from the magnetosphere.
Aleksey Generozov, The University of Texas at Austin
Low Mass Binaries Are Bound from Birth
Observations show that most main sequence stars, unlike our Sun, are members of systems with two or more stars. Exactly how these systems form and when these stars become gravitationally bound together remains debated, since resolving the earliest stages of star formation is challenging. I will discuss how multiple star systems form and evolve in simulations of star cluster formation representative of typical Milky Way conditions that include all key physics and stellar feedback mechanisms. In particular, I will show ~70-80% of binaries form as bound systems, rather than from capture of initially unbound stars.
Other Events in This Series
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Stars, Planets, and ISM Seminar
Stars, Planets, and ISM Seminar
No meeting
12:00 pm – 1:00 pm • In Person
Jan
22
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Stars, Planets, and ISM Seminar
Stars, Planets, and ISM Seminar
No talk scheduled
12:00 pm – 1:00 pm • In Person
Jan
29
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Stars, Planets, and ISM Seminar
Stars, Planets, and ISM Seminar
Two talks by Astronomy Department graduate students
12:00 pm – 1:00 pm • In Person
Speaker(s): Nathanael Burns-Watson - The University of Texas at Austin and Carlos Jurado - The University of Texas at Austin
Feb
5
2025
Stars, Planets, and ISM Seminar
Stars, Planets, and ISM Seminar
No talk scheduled
12:00 pm – 1:00 pm • In Person
Feb
12
2025
Stars, Planets, and ISM Seminar
Special Seminar: galactic.ai — The New Frontier in Cosmology and Astrophysics
Special Seminar by ChangHoon Hahn of Princeton University
12:00 pm – 1:00 pm • In Person
Speaker(s): ChangHoon Hahn - Princeton University
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Stars, Planets, and ISM Seminar
Special Seminar: Beyond the Observable - A Machine Learning perspective on modern Cosmology
Special Seminar by Carolina Cuesta of MIT and Harvard University
12:00 pm – 1:00 pm • In Person
Speaker(s): Carolina Cuesta - MIT and Harvard University
Feb
26
2025
Stars, Planets, and ISM Seminar
Stars, Planets, and ISM Seminar
No talk scheduled
12:00 pm – 1:00 pm • In Person
Mar
5
2025
Stars, Planets, and ISM Seminar
Stars, Planets, and ISM Seminar
No talk scheduled
12:00 pm – 1:00 pm • In Person
Mar
12
2025
Stars, Planets, and ISM Seminar
Stars, Planets, and ISM Seminar
Two talks by Astronomy Department graduate students
12:00 pm – 1:00 pm • In Person
Speaker(s): Erica Sawczynec - The University of Texas at Austin and James Mang - The University of Texas at Austin
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26
2025
Stars, Planets, and ISM Seminar
Stars, Planets, and ISM Seminar
Two talks by UT Astronomy graduate students
12:00 pm – 1:00 pm • In Person
Speaker(s): Malia Kao - The University of Texas at Austin and Shelby Courreges - The University of Texas at Austin