Detecting the first stars through gravitational lensing

by Prof. Erik Zackrisson

Uppsala University
at Astrophysics and Cosmology Seminar

Wed, 06 Apr 2022, 11:10
Sacta-Rashi Building for Physics (54), room 207


The first generation of stars – the metal-free Population III – played an important role in the early Universe by ending the cosmic dark ages, by producing the first elements beyond hydrogen, helium and lithium, and possibly by seeding the Universe with the first black holes. Such stars are predicted to be predominantly more massive than stars that form in later stellar generations, but no clear-cut detections of Population III objects have so far been made. Extreme magnifications due to gravitational lensing by foreground galaxy clusters could make it possible to detect such stars at very high redshifts, and a massive, lensed star – “Earendel” – was recently discovered at redshift z~6, in an epoch about 900 million years after the Big Bang. Upcoming observations with the James Webb Space Telescope will soon help us constrain the nature of Earendel and also search for other examples of lensed, high-mass stars at z~6-17. Here, I will outline what we can hope to learn about Population III stars from data of this kind.

Created on 02-04-2022 by Zitrin, Adi (zitrin)
Updaded on 02-04-2022 by Zitrin, Adi (zitrin)