A Canadian astrophysicist who keeps a close eye on the stuff spit out by black holes as they consume stars will tell Nanaimo astronomers all about her work this week.
Nanaimo Astronomy Society’s first meeting of the year on Thursday, Jan. 27, will feature guest speaker Alexandra Tetarenko, who will explain how the James Webb Space Telescope will advance knowledge about black holes.
Tetarenko, from Calgary, earned her doctorate at the University of Alberta and worked at the Mauna Kea Observatories in Hawaii with the East Asian Observatory’s James Clerk Maxwell Telescope. She started her NASA Einstein Fellowship at Texas Tech University last fall with a focus on studying stellar-mass black hole systems in our galaxy and will be conducting observations through the James Webb Space Telescope.
“Webb can study a lot of different black holes, from the really big ones that exist at the centres of galaxies – it’s also going to be able to study the smaller ones in our galaxy,” Tetarenko said. “So there’s actually millions to billions of these smaller black holes that have a mass on the order of the mass of our sun.”
In some cases, black holes are found in binary systems in which they are paired with a companion star.
“The black hole will pull material off of the companion star and eat it, basically, but it doesn’t just eat all that matter. It also spits a bunch of it back outward in the form of these jets and that’s what I focus on studying, basically,” she said.
The jets black holes spit out are a combination of matter and radiation, but there is an open question about the composition of the jets, given that not much actual matter is able to escape the gravitational pull of a black hole.
“Whether they’re just electrons and positrons or whether there’s just some kind of baryonic matter, like protons, in them, which is much heavier, that’s still the debated question,” Tetarenko said.
She said with the James Webb telescope, scientists will be able to study how the intensity of the light from black hole jets varies over time scales, which will allow measurement of the physical size, energy output and speed of the jets. The telescope will also provide data on how the light produced by the jets varies relative to electromagnetic frequency. The combined data will help build a broadband spectrum of light and energy produced, specifically, the point in the jets where particle acceleration begins.
“It’s this key area that we really want to study because we don’t understand how these things are launched at all, so being able to study that specific area is really important and the JWST happens to probe the specific part of the electromagnetic spectrum where that break is, so it’s going to be able to transform our science in that spectral domain,” Tetarenko said.
The JWST, Tetarenko said, promises to move scientific discovery in astrophysics forward beyond what the Hubble Space Telescope was able to provide.
“It’s really awesome to be able to work with such a new telescope and one that going to be so transformative for our science…” she said. “It’s like Hubble on steroids. It’s going to be absolutely amazing.”
Nanaimo Astronomy Society’s January meeting happens at 7 p.m. on Jan. 27. The meeting is for the society’s paid members, but newcomers can attend one meeting for free. For more information, visit www.nanaimoastronomy.com.