Characterizing the circum/inter-galactic gas in emission around z~2-3 quasars

Recently, enormous (> 200 kpc) Lyman-alpha nebulae (ELAN) have been discovered around radio-quiet z~2-3 quasars. Being currently explained as powered by the ionizing radiation of quasars, these bright large-scale nebulosities suggest the possibility of studying the circum/inter-galactic gas in emission around individual systems on very large scales. Motivated by these discoveries, we have been conducting a statistical census of z~2-3 quasars using the narrow-band and IFU technique with the aim to determine the frequency of this phenomenon, as well as to study their size, luminosity, covering factor, and the gas physical properties.
In the first part of my talk I will present the results of the QSO MUSEUM survey
(Quasar Snapshot Observations with MUse: Searching for Extended Ultraviolet eMission), which comprises 61 z~3 quasars observed with the MUSE/VLT instrument.
In the second part of the talk I will then focus on one of these objects which suggests that
Lyman-alpha could be used to trace the inspiraling motions of the cool circum-galactic medium,
predicted to take place on hundreds of kpc within massive halos.
I will conclude by summarizing my on-going observational effort in characterizing the ELAN phenomenon, and large-scale gas structures around quasars.