I am a PhD candidate in the Department of Astronomy and Astrophysics at the University of Toronto. I work with my thesis supervisor Prof. Marten van Kerkwijk and grad student Epson Heringer, both of the department, Prof. Philip Chang, a former CITA postdoc and now professor at the University of Wisconsin Milwaukee, and Dr. Rüdiger Pakmor, postdoc at the Heidelberg Institute for Theoretical Studies.
I research white dwarfs, the remnants of Sun-like stars left behind after they've exhausted their nuclear fuel. Specifically, I investigate mergers of two carbon-oxygen white dwarfs to determine if and how they produce type Ia supernovae, the most powerful thermonuclear explosions in the universe. While supernovae are a hundred million times brighter than the Sun, white dwarf themselves are incredibly faint, preventing direct observation of phenomena such as mergers by even the most powerful telescopes. This makes computer simulations one of our most potent tool for understanding merger physics and post-merger evolution.
My work has utilized 3D hydrodynamic simulations to explore how properties of the merged object, or "merger remnant", depend on the masses of the two merging white dwarfs. I have also examined how shear flows within the merger rapidly generate powerful magnetic fields through magnetic dynamo action. The temperature and rotational profiles of the merger remnant, as well as the presence of a magnetic field, shape the post-merger evolution of the remnant. I am currently working with 1D semi-analytical models of this evolution to quantify the influence of rotation and magnetic fields, and identify the conditions that lead to an explosion.
I also did observational work on the dark matter halos of early-type (elliptical) galaxies earlier in my career. Dark matter is ubiquitous throughout the universe, and dark matter halos are believed to comprise the majority of the mass within galaxies, guiding their birth, life and final fates. The presence and distribution of dark matter is indirectly detected through its interaction with the "normal" baryonic matter of stars, gas and dust. This makes it particularly difficult to detect dark matter in early-type galaxies because they lack gas disks that extend far from their galactic centre. The introduction of integral field spectroscopy has now made it possible to use faint populations of stars in lieu of gas, allowing us to probe the dark matter halos of thousands of early-type galaxies. In my work I reduced raw data of four early-type galaxies from the VIRUS-P spectrograph, and derived the shapes of their dark matter halos through fitting the data to theoretical galactic models.
Other Astro Interests
I'm passionate about public outreach and education. In the last four years, I've been part of the executive committee of the U of T AstroTours, a Department of Astronomy grad student-run event series. AstroTours features lectures by members of the department, night-sky observing and planetarium shows. I've also assisted with planning department special events.
Office: MP1203A (McLennan Building in St. George Campus)
Mailing Address: Chenchong Zhu
Department of Astronomy & Astrophysics
University of Toronto
50 St. George Street Room 101
Toronto, ON, Canada