Meet the AAS Keynote Speakers: Prof. dr. Victoria Kaspi and Dr. Paul Scholz

In this series of posts, we sit down with some of the plenary speakers from the 240th AAS meeting to learn more about them and their research. You can see a full schedule of their conversations hereand read our other interviews here

“Magnetars are the perpetrators of (almost) everything” is the title of an astrobit from a few years ago, and Dr. Scholz, one of the subjects of today’s Astrobites article, would generally agree.

Today’s post will collectively focus on the work and career of Dr. Victoria Kaspi, a professor of physics at McGill University, and her former student and collaborator, Dr. Paul Scholz, a postdoctoral researcher at the Dunlap Institute for Astronomy and Astrophysics at the University of Toronto. As principal investigator of the Canadian Hydrogen Intensity Mapping Experiment (CHIME) collaboration, Dr. Kaspi one of many astronomers working to unravel the mystery of fast radio bursts (FRBs) – extremely fast and energetic bursts of emission that we observe in the radio band – and figuring out how these phenomena can be used to answer fundamental questions about the universe. The CHIME instrument is a unique stationary radio telescope that almost instantly constructs very broad density maps of hydrogen, making it ideal for both large-scale science – e.g. measuring the expansion history of the Universe – and at fast scales – e.g. rare transient or periodically emitting objects such as FRBs and pulsars

The Power of Dr. Kaspi’s scientific collaboration is evident as she will receive two awards this year at AAS, focusing on two different areas of her expertise. On behalf of the entire CHIME partnership, she and Dr. Scholz de Berkeley Prize for the discovery of a highly luminous radio burst from a magnetic (a dense stellar remnant with an unusually strong magnetic field) in our Milky Way galaxy and the large catalog of FRBs compiled by the CHIME team. Until their observation, FRBs were a purely extragalactic phenomenon and their origin was an open question, so their discovery showed us that the words of that Astrobite from a few years ago might sound – magnetars are capable of producing radio bursts so we can see them from extragalactic distances, which is why some FRBs may be magnetars. dr. Scholz recalls the moment they first made that observation and recounts their excitement: “That was one of those moments when it felt like nature was throwing something at you and it’s telling you something — it’s [the kind of observation] that has consequences as soon as you see it”. That observation was indeed groundbreaking in the field of FRBs and opened the door to the possibility of more such discoveries in our own Milky Way galaxy.

dr. Victoria Caspi. Source: McGill University

dr. Kaspi also receives the Shaw Prize, which she and her colleague Dr. Chryssa Kouveliotou is awarded for their independent work on magnetars. dr. Kaspi led study on observational abnormal X-ray pulsars who have no clear understanding of the origin of the X-rays – her observational work showed that these too were performed by magnetars. Continuing to monitor the sources, they found this phenomenon to be quite normal and provided insight into the range of possible magnetic phenomenology and what causes these systems.

Looking back

At McGill University, Dr. Kaspi plans to pursue a career in particle physics, especially after a summer at CERN in Switzerland. Then her graduate program at Princeton required students to do some sort of project separate from their planned thesis work. At the time, she thought astronomy was cool, but had no real experience in it. So she found herself being a physics freshman who had to learn what “RA” and “Dec.” intended (axes for the standard astronomical coordinate system). In fact, Dr. Kaspi remembers much of the astronomy she knows she learned by teaching! Her first astronomy project was a pulsar observation program – and she loved it. She recalls being impressed by using a large telescope and collecting the data, and realized that she liked that much more than her previous projects in particle physics.

Now a professor at McGill University, Dr. Kaspi expanded this work in pulsars and then magnetars to work towards answering the question: What are FRBs? Recent work from the CHIME collaboration has shown that some may be magnetars, but we don’t know what all of them are. dr. Kaspi explained that it’s helpful to break it down into smaller questions. For example, do all FRBs have some spikes in their signal, implying they are catastrophic events? Are there different classes to produce FRBs, and are FRBs a homogeneous, more uniform population or a heterogeneous, mixed population?

In addition to understanding these fundamental characteristics of FRBs, Dr. Kaspi and her team explore the use of FRBs as new cosmological probes with new techniques. One of those ways is to study re-ionization, the universe’s last major phase change as it transformed from primary neutral gas to ionized gas. FRBs are great probes of ionized gas because they can help detect scattering due to the inhomogeneity of gas in the early Universe.

dr. Paul Scholz. Source: University of Toronto

dr. Scholz began his career in science the same way Dr. Kaspi – he entered his bachelor’s degree at the University of Victoria and studied physics. After a few co-ops (the Canadian equivalents of Giant) where he got the chance to dip his toes in the field, he began to seriously consider astronomy research as a viable career. This interest led him to graduate school at McGill University, where he was supervised by Dr. Kaspi and worked on X-ray observations of magnetars. As he neared the end of his PhD in 2015, he was accidentally drawn to the world of FRBs when he and his group launched the first repetition FRB while reprocessing some pulsar observations from the Pulsar Arecibo L-band Feed Array (PALFA) instrument. Coincidentally, he was already applying for postgraduate positions in hopes of studying the exciting new subject of FRBs, so this was a serendipity in that area.

Since his PhD, he has held a postdoctoral position at the Dominion Radio Astrophysical Observatory (DRAO), where he was part of the team overseeing the development and construction of the CHIME instrument. Since CHIME is designed to continuously monitor large areas of the sky for FRBs, the instrument receives several terabytes of data – the equivalent of few laptop hard drives – per second, so it may not be feasible to save all the data for later use. analysis. Instead, Dr. Scholz that the real beauty of the telescope’s engineering is in the software pipeline, which helps deal with the “fire hose of [the data intake rate]† Near the instrument are several hundred computers – housed in a pair of radio frequency (RF) shielding shipping containers – that immediately parse the data so that it is only stored when an FRB has occurred.

Now a postdoctoral researcher at the Dunlap Institute, Dr. Scholz continued his work on the software and data analysis pipelines of the CHIME FRB instrument, but has also come full circle as he again works on magnetars, looking for high-energy observations counterparts to the FRB observations made with CHIME.

Looking forward

In addition to research, Dr. Kaspi how important it is to try to pave the way for future generations of scientists. While in college, she recalls feeling “a lot of fear,” recalling advocating for more women’s toilets in the physics building — there was one in the entire building back then, compared to countless men’s toilets in convenient locations. Still, she advises that while this kind of pioneering is important, you can’t do everything, and it’s far better to focus on doing some things really well. “The years go by very quickly!” she noted.

dr. Recognizing the value of the cooperatives in helping him identify his enthusiasm for astronomy, Scholz advises students to explore their interests by trying research as early as possible. In addition — and perhaps a little more jokingly — he advises aspiring astronomers to always document their code.

During the interview, Dr. Kaspi the excellence of her students and the whole CHIME collaboration. “They are the lifeblood and energy of the group. Well, I think I still have some energy…” she joked. Among her many students are Ketan Sand, who wrote a paper using CHIME data to analyze a periodically repeating FRB, and Astrobiter Alice Curtin. dr. Kaspi also highlighted a recent analysis paper by student Alex Josephy, who examined the aerial distribution of FRBs and found no apparent correlation with the galactic plane to determine whether the FRB population is contaminated with nearby intermittent radio pulsars.

Learn about the work of the CHIME team and the FRBs they demystify at the Berkeley Prize plenary session (4:40pm PT – 5:30pm PT Thursday, June 16, 2022) and about magnetars at the Shaw Prize special session (Monday, June 13, 2022 at 10 a.m. PT – 11:30 a.m. PT).

Astrobite co-written by Sahil Hegde and Olivia Cooper

Astrobite edited by Graham Doskocho

Featured Image: American Astronomical Society

About Sahil Hegde

I am a freshman astrophysics PhD student at UCLA. I currently use semi-analytical models to study the formation of the first stars and galaxies in the universe. I received my bachelor’s degree from Columbia University and am originally from the San Francisco Bay Area. Outside of astronomy, you’ll find me playing tennis, surfing (read: extermination), and playing board games/TTRPGs!

#Meet #AAS #Keynote #Speakers #Prof #Victoria #Kaspi #Paul #Scholz

Leave a Comment

Your email address will not be published. Required fields are marked *