Powered by Indico
v3.2.9
Title: Understanding Reionization with 21cm observations of high-redshift analog galaxies
Speaker: Alexandra Le Reste
Affiliation: Stockholm University
Time: Thursday 12 January 2023, 1400 to 1500
Location: 11134Å
Abstract:
About 400 Myr after the Big bang, the Universe transitioned from primarily neutral to ionized. Primeval star forming galaxies are thought to be the main sources that caused the Reionization of the Universe. However, the way ionizing radiation escaped the neutral gas of galaxies to ionize the intergalactic medium is still poorly understood, due to the limits of high redshift observations. To remedy this, nearby galaxies similar to high-redshift objects can be used to get detailed information on the processes at play during Reionization. Haro 11 is the closest (z~0.02) galaxy with confirmed ionizing radiation escape and is considered an observational laboratory to study reionization from the local perspective. However, a decade of attempts to map the neutral interstellar medium of this galaxy yielded contradicting results. I will present MeerKAT 21cm HI observations of Haro 11 that reveal the neutral gas distribution enabling the escape of ionizing photons in a galaxy for the first time. We found that merger interactions have played an essential role in the escape of ionizing photons to the intergalactic medium. I will discuss how galaxy mergers can contribute to the reionization of the Universe.