Affiliation: University of Milano Bicocca

Contribution: Oral

Title: Unveiling the cosmic web through Lyα emission: an ultra-deep observation with MUSE

Abstract: The existence of filaments connecting galaxies within which galaxies form has been a long-standing prediction of theories describing structure formation in a Universe dominated by cold dark matter. However, direct imaging of these filaments has remained elusive until the deployment of large-format integral field spectrographs such as the Multi Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope. I will present a novel ultradeep (150-hour) observation of Lyα emission from a cosmic web filament linking two massive galaxy halos, each hosting a luminous quasar, at redshift z~3.22 in the Muse Ultra Deep Field. This transformational dataset, coupled with the ionization field of the two quasars, unlocks the ability to study the properties of an emitting structure that extends for almost 700 kpc between and sideways of two nodes in the cosmic web. I will present our characterization of the Lyα surface brightness profile both along the filament and in the transverse direction, measuring the transition radius between the circumgalactic and intergalactic medium. I will explore the implications of this unique discovery, comparing the observables with predictions from numerical simulations. Lastly, I will discuss the quasars environment as probed by Lyα emitters in the MUSE field. This field represents a unique laboratory for studying cosmic structures, providing valuable insights into their nature and the clustering properties of dense structures beyond cosmic noon.

This contribution can be found here (pdf).