Enormous Lyα nebulae (ELANe) represent the extrema of Lyα nebulosities. They have detected extents of > 200 kpc in Lyα and Lyαα luminosities > 1044erg s-1. The ELAN population is an ideal laboratory to study the interactions between galaxies and the intergalactic/circumgalactic medium (IGM/CGM) given their brightness and sizes. The current sample size of ELANe is still very small, and the few z ≈ 2 ELANe discovered to date are all associated with local overdensities of active galactic nuclei (AGNs). Inspired by these results, we have initiated a survey of ELANe associated with QSO pairs using the Palomar and Keck Cosmic Web Imagers (PCWI/KCWI). In this letter, we present our first result. the discovery of ELAN0101+0201 associated with a QSO pair at z = 2.45. Our PCWI discovery data shows that, above a 2-σ surface brightness of 1.2 × 10-17erg s-1cm-2arcsec-2, the end-to-end size of ELAN0101+0201 is & 232 kpc. We have conducted follow-up observations using KCWI, resolving multiple Lyα emitting sources within the rectangular field-of-view of ≈ 130 × 165 projected kpc2, and obtaining their emission line profiles at high signal-to-noise ratios. Combining both KCWI and PCWI, our observations confirm that ELAN0101+0201 resides in an extremely overdense environment. Our observations further support that a large amount of cool (T ~ 104K) gas could exist in massive halos (M & 1013M⊙) at z ≈ 2. Future observations on a larger sample of similar systems will provide statistics of how cool gas is distributed in massive overdensities at high-redshift and strongly constrain the evolution of the intracluster medium (ICM).
|Original language||English (US)|
|State||Published - Mar 28 2018|
- Galaxy: halos
- Intergalactic medium
- Quasars: emission lines
ASJC Scopus subject areas