Monday, March 14, 2022
12:00 – 12:30pm
Taylor Hutchinson, Texas A&M
Peering through the Cosmic Fog: What Powers the UV in Galaxies During Reionization?
Abstract: In the myriad observational and theoretical studies surrounding the reionization era (z~15-6), one point becomes abundantly clear: we are still in the discovery phase of galaxies during this time. The rest-UV spectra of these galaxies contain a rich variety of nebular metal emission lines which hold highly valuable information about the massive stars and physical conditions in these sources. Such UV nebular lines are targetable at these redshifts, yet have been unexplored except in rare, individual cases. In this talk I will discuss a Keck/MOSFIRE spectroscopic search for rest-UV nebular metal lines in reionization-era galaxies in the CANDELS fields, starting with an analysis of a spectroscopically-confirmed galaxy at z=7.5. Finally, I will highlight the exciting science that we can expect from observations in the IR using the JWST, opening the door to a new era of high-redshift science.
Bio: Taylor is a PhD Candidate and NSF Graduate Fellow at Texas A&M University, working with Casey Papovich on studying the rest-UV spectroscopic properties of high-redshift galaxies during the Epoch of Reionization (involving both NIR spectroscopy and detailed photoionization modeling). After her PhD, she will be moving to Goddard Space Flight Center as a NASA Postdoctoral Program Fellow, to work with Jane Rigby on a variety of exciting high-redshift science to come from the JWST.
Riccardo Arcodia, Max Planck Institute for Extraterrestrial Physics
X-ray quasi-periodic eruptions: what are they and where do we stand?
Abstract: Quasi-Periodic Eruptions (QPEs) are a new fascinating type of high-energy transients related to black hole accretion, showing high-amplitude bursts of X-ray radiation recurring every few hours. So far only a handful of such sources has been found, originating from the central massive black holes in the nuclei of low-mass galaxies. I will present an overview of their multi-wavelength observational properties and I will also discuss a few possible scenarios for their origin. I will focus particularly on results coming from our blind search with the eROSITA X-ray telescope, which is scanning the X-ray sky and provides the only current systematic method to find more QPEs.
Bio: Riccardo Arcodia was born and raised in Italy. He took both his Bachelor’s degree in Physics, and Master’s degree in Astrophysics and Space Physics, at the University of Milan-Bicocca (Milan, Italy). He then moved to Germany to pursue his PhD in Physics and Astronomy at the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, under the supervision of Prof. Kirpal Nandra and Dr. Andrea Merloni. Since graduating in 2021, Riccardo has been a postdoctoral researcher in the High Energy Astrophysics group at MPE. Riccardo’s research focuses on studying accretion onto black holes of different masses, from X-ray and optically bright active supermassive black holes to stellar-mass black holes.