Speaker:

Lamiya Ashraf Mowla, PhD, Assistant Professor, Department of Physics and Astronomy, Wellesley College, USA.

Abstract:

The most distant galaxies observed date back to when the Universe was only 5% of its current age, with progenitors of galaxies like the Milky Way being about 10,000 times less massive. Using JWST and the magnification provided by gravitational lensing, these low-mass galaxies can be detected and studied in detail. In this work, we present JWST observations of the “Firefly Sparkle,” a strongly lensed galaxy at (z = 8.3) in the CANadian Unbiased Cluster Survey (CANUCS). This galaxy features massive star clusters cocooned in a diffuse arc, showcasing characteristics of a young, gas-rich galaxy in the early stages of formation. The unresolved clusters display exceptionally high surface densities, surpassing those of Milky Way globular clusters and nearby young star clusters, along with nebular-dominated spectra, low metallicity, high gas density, and elevated electron temperatures, suggesting a top-heavy initial mass function (IMF). These observations provide the first spectrophotometric view of a typical galaxy at Cosmic Dawn, highlighting JWST’s capability to investigate the co-evolution of galaxies and star clusters. I will also discuss plans to expand this work using future JWST cluster observations, aiming to deepen our understanding of the evolution of galaxy.

Relevant reading:

1. Mowla et al. 2024, “Formation of a low-mass galaxy from star clusters in a 600-million-year-old Universe,” Nature.
2. Mowla et al. 2024, “The Firefly Sparkle: The Earliest Stages of the Assembly of A Milky Way-type Galaxy in a 600 Myr Old Universe,” submitted.
3. ওয়েবের দেখা গ্যালাক্সি ফায়ারফ্লাই স্পার্কল যেন এক ঝাঁক জোনাকি; কাসা নিউজ।

Dr. Mowla will give the talk in-person at IUB. The event is open to students and researchers of all universities both offline (at IUB) and online. If you RSVP and want to join online, a google meet link will be shared with you before the event begins.