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Marcin Sawicki
Canada Research Chair in Astronomy


I seek to understand how galaxies formed and evolved when the Universe was only a fraction of its present age. My research is focused through three key projects:

  1. (1)The massive, 200-hour JWST Guaranteed Time Observations CANUCS program that will let us investigate in detail the inner workings of thousands of low-mass galaxies at Cosmic Noon (z~2) and Cosmic Dawn (z>6). With the successful JWST launch on December 25th, our CANUCS data will start flowing in late summer 2022! 

  1. (2)The 68-night CFHT CLAUDS survey that together with affiliated deep surveys from other telescopes lets us use several million galaxies over a wide redshift range to do enormously large statistical studies of the processes that drive galaxy evolution.  CLAUDS is now joined by its newer sibling, DEUS, which aims to cover 10 sq degrees in the Euclid Deep Field North and study how galaxy properties relate to their location within the high-redshift Cosmic Web.

  1. (3)The GIRMOS AO-fed, multi-IFU spectrograph now under construction by a partnership of Canadian institutions, including our team at Saint Mary’s. GIRMOS will let us do detailed, spatially-resolved studies of 100’s of distant galaxies when commissioned at Gemini-North later this decade.

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2022 August 4:    Evolved High-Redshift Globular Clusters Captured by JWST

A number of our group members are closely involved in an exciting Webb-based research paper that just got submitted for publication (you can see it on arXiv here).

Our paper describes our discovery of what we believe to be old globular clusters in a spectacular-looking very distant galaxy that we call "The Sparkler".  Our own home galaxy, the Milky Way, hosts about 150 globular clusters, which are clumps of old stars that orbit the galaxy and that are believed to be the oldest, first-to-form bits of our galaxy.  No-one can tell for sure how old these globular clusters in the Milky Way are (decades of work have told us that they are really old, but the precise ages have been elusive). However, knowing their exact age would tell us a lot about when and how our home Galaxy was born. 

The significance of our discovery of old globular clusters in The Sparkler, whose light was emitted 9  billion years ago (when the Universe was just 1/3rd of its current age), is that we are able to measure its globular clusters’ ages much more precisely than is possible for globular clusters in the Milky Way.  Simply put, we observe The Sparkler and its globular clusters much earlier on in their lifetimes than is possible to do for the Milky Way, This gives us a lot more precision in telling what happened in The Sparkler around its time of birth than we can ever do for our own Galaxy. 

And so, we find that The Sparkler’s globular clusters were already very old at the time their light left them on its journey to us… in fact, they were already 4 billion years old at that time, which is when the Universe was only about 4.5 billion years old. This means that the globular clusters in The Sparkler must have formed very soon after the Big Bang — when the Universe was only about 500 million years old, or about just 3.5% of its present age.  Closer to home, the significance of our discovery is that the Sparkler’s globular clusters are similar to those of our own home Milky Way galaxy, then our home galaxy’s oldest parts must have also started forming very shortly after the Big Bang.

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