The history of galaxies in the early Universe remains substantially unknown. The mystery surrounding these galaxies is, in large part, a result of the epoch in which they existed. During the epoch of reionization (z>6), the Universe experienced its last major phase change, where the neutral gas permeating the intergalactic medium [IGM] became ionized. Light emitted from early galaxies was often blocked by this neutral gas (or "cosmic fog"), preventing restframe ultraviolet [UV] spectroscopic studies of this epoch except for faint traces of light detectable in the near-infrared [NIR] from the brightest sources. Prior to 2022, the high-redshift field was restricted due to limited ground- and space-based instrumentation probing NIR wavelengths and beyond. During this time, much of what we learned spectroscopically about these galaxies came from a handful of bright UV metal emission lines or far-infrared [FIR] emission (generally with only 1-2 lines detected in individual galaxies), data which only came after fighting for hours using the most massive telescopes on the ground and in space.
Since the advent of JWST, the high-redshift field has exploded with new science probing wavelengths and redshifts previously inaccessible. Using the advanced spectroscopic NIR capabilities of the JWST, we have been able to find not only increasingly distant galaxies but also to characterize sources that exist within the heart of the epoch of reionization [EoR]. In this talk, I will discuss the state of the high-redshift field before and after the launch of JWST -- highlighting our work from the Cosmic Evolution and Early Release Science [CEERS] survey, among other key early release science [ERS] & Cycle 1 programs. These new data have led to the discovery of an unexpected abundance of bright galaxies and active galactic nuclei [AGN] in the EoR, providing insights into the roles that the nature of these early galaxies and the nurturing from their environments played in the reionization of the Universe.
Astro Colloquium and 'coffee & cookies' department gathering (3:45-4:00pm)
Please join in 538 Davey or click the link to join: https://psu.zoom.us/j/93131536409