On Monday February 22, astrophysicist Jedidah Isler, Ph.D came to Bryn Mawr to speak about her research on quasars and her work advocating for women of color in physics and STEM in general. I attended both her 30 minute talk with Bryn Mawr physics students and her colloquium talk that same night.
“Dr. Jedidah Isler is a native of Virginia Beach, VA and a lifetime lover of the night sky. A graduate of the Dozoretz National Institute for Mathematics and Applied Sciences (DNIMAS) program at Norfolk State University, Dr. Isler later received a Masters in Physics as part of the initial cohort in the Fisk-Vanderbilt Masters to Ph.D. Bridge Program, a pioneering effort to expand access to advanced STEM degrees for students of color. Dr. Isler continued her educational pursuits at Yale University, where her research in astrophysics was supported by nationally competitive fellowships from NASA, the National Science Foundation (NSF) and the Ford Foundation. In 2014, Dr. Isler became the first African-American woman to receive a Ph.D. in Astrophysics from Yale, completing an award-winning study that examines the physics of particle jets emanating from supermassive black holes at the centers of distant galaxies. She is presently an NSF Astronomy & Astrophysics Postdoctoral Fellow at Vanderbilt University and participates in the Future Faculty Leader program at Harvard University’s Center for Astrophysics.
Throughout her career, Dr. Isler has remained a fierce advocate for the inclusion and empowerment of students from underrepresented backgrounds in the sciences. She has worked with numerous museums, libraries, observatories, and schools across the country on outreach and engagement efforts designed to inspire a new generation of STEM leaders and has established herself as an inspirational voice championing access in the field of Astrophysics and in science education.”
Dr. Isler started by describing what a black hole is– something that is so massive that not even light can escape. Black holes accrete mass. Some black holes are binary systems hundreds of times greater than the mass of the sun. Others are super massive (millions of times greater than the mass of the sun) and act as the cores of galaxies. Every galaxy has a super massive black hole at the core.
She then showed us x-ray signals of star positions over many years collected by the Keck UCLA group. They traced these x-ray signals to find the center of the gravitational potential well. In agreement with Keppler’s Law, they were able to calculate the volume mass inside to conclude that there was a super massive black hole present.
Isler then shifted to her research focus: black hole jets and their interaction with their surrounding environment. We know that black holes have jets because they visually show up on telescopic spectroscopy views, but zooming in until the image is unresolved does not tell us much about what it is, how it functions, and why it is there. This is where we turn to astrophysics to predict based on calculations and measurements. Black hole jets indicate an active galactic nuclei, also known as a quasar or blazar, where the core of the galaxy takes in lots of material. An accretion disk surrounds the core. Isler also pointed out the difference between a quasar and blazar. They look the same, but a blazar is spatial, not temporal. A quasar is only temporal.
Isler wanted to find out why the blazar jets are not continuous. Using special relativity and super luminal movement presented the problem of running into the Universal speed limit. Instead, she used the Geometric effect and Doppler effect and observed that the luminosity of the jet was boosted while the timescale was reduced. The double peak spectrum was unique to blazars. To determine where the jet was being emitted from, she looked at the broad line region on short time scales and compared emission line curve spectroscopy for multiple sources.
She looked for structures and complexities of jet emissions specific to those near black holes.
As for the source of blazar jets, she has yet to confirm whether they are created very near the center of the black hole by a magnetic field spun up or by the black hole itself spinning and creating a magnetic field that composes the jet. The distance between the jet and the black hole is to be determined. It cannot simply be measured off a telescopic view because of general relativity and point of view.
The colloquium talk concluded with Isler describing her work advocating for inclusion and empowerment of minorities in STEM. She hosts a webcast called Vanguard every first Tuesday of the month to discuss challenges and advice.
Her 5 Tips for Academic Success are:
- Dream (and dare) obnoxiously
- Invest Selfishly
- Persevere Relentlessly
- Succeed Unapologetically
- Generate Opportunity
My favorite tip she gave during the 30 minute students-only talk was to not do something just because you think someone of that profession does that. I feel bad enough that I do not volunteer at a hospital because I think someone who is pre-health does that.
During the Q&A, Isler described her typical day to include sitting at her computer with writing code and analysis on her data sent to her remotely from Chilean telescopes and attending lots of meetings. I asked her what program she uses for data graphics and she said she started with IDL and now uses Python.