MATs (Monday Afternoon Talks), 11/06/2023 — Speakers: Heidi White & Amy Secunda

Monday November 6, 2023 3:00 pm

MATs (Monday Afternoon Talks)

3:00pm – 3:30pm, Heidi White

Effective and meaningful engagement of underserved and disproportionately impacted communities in STEM learning
Developing science education initiatives which target the needs of underserved and disproportionately impacted groups helps bridge educational disparities and is crucial for equal access to STEM learning. By addressing the specific needs of these communities, we empower individuals to pursue STEM careers, fostering a more diverse scientific community and enriching the scientific landscape. Ultimately, inclusive learning initiatives promote social justice, advance scientific knowledge, and contribute to a more equitable and prosperous society.
In this talk, I will discuss strategies that I have identified over the past decade for effectively and meaningfully engaging these communities in STEM learning, drawing from firsthand experiences in developing astronomy education initiatives both in Africa and among remote indigenous communities in Canada. Examples of which include centering community-specific approaches, the development of living, adaptive curricula tailored to address the unique needs of learners, and strategies for delivering effective instruction in low-connectivity environments. I will also discuss the importance of cultivating teaching teams that mirror the intended audience, and the role representation plays in nurturing an inclusive learning environment. Finally, I will explain why sustainable program management is essential for community engagement and creating enduring, long-term impact. Throughout my presentation, I will candidly reflect on my own journey in confronting personal biases and acknowledging the privilege inherent in my identity as a white woman from settler heritage working in these contexts.

3:30pm – 4:00pm, Amy Secunda

Probing accretion disk structure beyond the standard thin disk model
I will present a numerical and observational approach to studying the structure and internal physics of quasar accretion disks (AD) using two types of disk reverberation mapping (RM). The first is the traditional continuum RM, which measures lags in the variability of quasar light curves from high to low frequency wave bands on the light-crossing time scale due to the reprocessing of light in different temperature regions of the disk. This method has been used for decades, however, the transfer function of this reprocessing and how it can be affected by local variability in the disk are not well understood. Multi-frequency radiation magnetohydrodynamic codes make it possible to directly simulate the reprocessing of light by a quasar disk. I will present results from new radiation Athena++ simulations and discuss how they can be directly compared to observations to better understand reprocessing. I will also discuss a second type of lag, the “long negative lag.” The long negative lag occurs when fluctuations in the outer UV/optical region of the disk are accreted inward on the longer inflow timescale leading variability from these fluctuations in high frequency bands to lag the corresponding variability at low frequency. Because the inflow rate, unlike the speed of light, also depends on disk properties, long lags can provide additional information about disk structure. I will outline the underlying theory of these long lags, present several possible detections, and discuss the prospect of detecting more in the near future with the Vera C. Rubin Observatory.


Hosts: Minghao Yue, Daniele Michilli


  • Heidi White, Universite de Montreal
  • Amy Secunda, Princeton University