Farewell to Dr Chiamaka Okoli

Chiamaka’s PhD defence on Dec. 4th, 2018 (image courtesy of Natacha Altamirano)

It is with great sadness that I share here the news of passing of my former PhD student, Chiamaka Okoli. Chiamaka successfully defended her PhD with the title “Dark Matter and Neutrinos in the Foggy universe” last December. Her PhD convocation at the University of Waterloo was scheduled for last week, on June 13th.

Post-defence celebration with cake at PI bistro; From left to right: James Taylor (co-supervisor), Chiamaka, Larry Widrow (Chiamaka’s PhD external examiner), me and my son Juyah, and Mike Hudson (images courtesy of Natacha Altamirano)

However, that was not meant to be. Chiamaka’s life was cut short on June 6th in McMaster hospital in Hamilton. You can read more about Chiamaka on Perimeter Institute’s website. If you wish to contribute to The Chiamaka Okoli Trust Fund, to help her family with funeral costs (which involves moving her body back to her native Nigeria), please contact Jamie Cooper as soon as possible.

But then, here is my story …

I first met Chiamaka in Fall 2012, when she joined the then recently established Perimeter Scholar International program. She had just finished the diploma program with Ravi Sheth at the International Centre for Theoretical Physics in Trieste, and was eager to work more on cosmological structure formation. We started working on understanding the profiles of dark matter haloes, establishing a novel paradigm to predict their concentration based on energy conservation. This led to Chiamaka’s first paper.

Figure 5 from Chiamaka’s first paper, comparing her prediction for concentration of dark matter haloes as a function their mass, with previous work.

Chiamaka then started her PhD program at the University of Waterloo, working with me and James Taylor.

Chiamaka’s second paper studied a novel possibility for tracing the fingerprints of cosmic neutrinos by how they could slow down the motion of dark matter haloes through dynamical friction. We predicted that, with proper modeling, this effect could be detected in current and future galaxy surveys.

A figure from Chiamaka’s second paper , showing how wakes of neutrinos can slow down clustered dark matter haloes, through their gravitational pull

And there was much more:

  • In her third and final publication, Chiamaka established the range of theoretical uncertainties in predictions for annihilation signal from dark matter haloes
  • She was working with me and Ue-Li Pen to test her theoretical predictions for dynamical friction due to neutrinos using TianNu simulations
  • She was working with Natacha Altamirano, Utkarsh Giri, and I to measure and understand the thermal Sunyaev-Zel’dovich effect from groups of galaxies, as seen by Planck satellite

So long, farewell …

Chiamaka’s final two years on Earth were embodiments of perseverance in the face of adversity. In August 2017, Chiamaka gave birth to her baby boy, Munachi. The same month, her mother passed away back home in Nigeria. In November 2017, while still on maternity leave, she submitted two papers to arXiv, and then started applying for postdoc positions. In January 2018, she came back to work. In February 2018, she was hit with her first near-fatal cerebral aneurysm, which she talked about in a facebook post, in its one-year anniversary. It took a few surgeries, as well as weeks and months of recovery in the McMaster hospital, as well as Grand River hospital and Rehab center for her to get back on her feet. Meanwhile, she was being contacted for postdoc interviews and offers. In September 2018, Chiamaka again came back to work, determined to wrap up her PhD thesis, which she managed to do by mid-October. She defended her PhD in December 2018. In March 2019, Chiamaka had a final cranioplasty surgery in Hamilton, so that she’d fully recover from her first aneurysm episode. Alas, it struck again in May, and ended her life.

Even though Chiamaka had postdoc offers, she ended up turning them down, and instead started looking for data science jobs in the area. The exact reason remains a mystery to me, but I would like to think the ordeal that she had gone through had given her a new perspective on life. I also would like to think that I understood all her struggles, and helped her as best as I could, even though that might just be wishful thinking.

Like all academics, Chiamaka’s legacy now propagates through those who read and study her work. They are all those open-ended questions and ongoing projects that will permeate through journals and workshops, along with the dreams of what she could have done with them, only if universe treated her more kindly.

And finally, her legacy continues through her 22-month old son, Munachi, who is still too young to know what is happening. I do hope I get to tell him at some point about his mother’s enthusiasm for cosmology, zest, determination and sense of humor (even when she couldn’t talk and had to write her thoughts, while in a hospital bed).

Farewell Chiamaka.

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