Nordita Astrophysics Seminars

Erik Zackrisson, "Gravitational lensing of stars in the early Universe"

Albano 3:6228 - Mega (22 seats) (Albano Building 3)

Albano 3:6228 - Mega (22 seats)

Albano Building 3


Hybrid talk: Mega (6228, Hus 3, Albano) +


Abstract: Individual stars are typically not detectable beyond the local Universe, but gravitational lensing by foreground galaxy clusters can in rare cases raise the brightness of extremely distant stars to observable levels. This gives us a unique opportunity to study star formation and stellar evolution in the early Universe. A handful of redshift z>1 stars were detected in the last 5-6 years using the Hubble Space Telescope, and several additional candidates have already been detected in the first few months of James Webb Space Telescope operations. The distance record is currently held by the star Earendel, recently discovered by our team at a redshift of z~6, which corresponds to an epoch less than one billion years after the Big Bang. Ongoing James Webb Space Telescopes surveys do however have the potential of detecting stars at even earlier epochs. In this talk, I will describe what we have learned from recent James Webb data on Earendel, and what we hope to learn from other gravitationally lensed, high-redshift stars in the years to come.