J-PAS: Discovery of RaJav, a bright spatially extended Ly$\alpha$ Nebula at z=2.25

Abstract

We report the discovery of a massive and potentially largest Ly$\alpha$ Nebula, RaJav, at z=2.25, associated with a quasar pair: the bright SDSS~J162029.07+433451.1 (hereafter J1620+4334) and the faint newly discovered quasar JPAS-9600-10844, at 2.265 $\pm$ 0.021 using the early data release (17 deg${}^2$) of the J-PAS. The quasar JPAS-9600-10844 embedded in the nebula is located at ~ 60.2 kpc (7.3'') from J1620+4334, and shows a compact structure with broad emission lines (> 3000 km/s), typical of active galactic nuclei. At a 2$\sigma$ surface brightness (SB) contour of $\sim 1.86\times 10^{-16}$ erg s${}^{-1}$ cm${}^{-2}$ arcsec${}^{-2}$, the nebula extends > 100 kpcs and has a total Ly$\alpha$ luminosity of $\sim 5.8\pm 0.7\times 10^{44}$ erg s${}^{-1}$ signify the presence of a giant Enormous Ly$\alpha$ Nebula (ELAN). The nebula traces an over density of quasars at redshift of 2.2-2.3 consistent with the progenitor of a massive galaxy cluster. The extended CIV emission indicates that the circum-galactic medium (CGM) is metal-enriched and not primordial. The current J-PAS observations suggest photoionization and shocks due to outflows as possible ionization mechanisms. The faint extended FUV and NUV continuum emission likely points to ongoing star formation around the two quasars, suggesting a complex interaction in their environments. These findings provide new insights into the environment of quasars and their role in shaping the dynamics and evolution of the CGM at cosmic noon. Further spectroscopic observations will be required to fully characterize the object's nature and its kinematic properties. This study demonstrates the unique capability of J-PAS to detect massive and rare Ly$\alpha$ nebulae, providing new insights into their properties, environments, and connections to large-scale structures in the cosmic web such as filaments and overdensities in a large cosmological volume.

6 pages, 5 figures, Revised version of the paper resubmitted to A&A after referee's report

References in corpus (11)

• Quasar Quartet Embedded in Giant Nebula Reveals Rare Massive Structure in Distant Universe
• The REQUIEM Survey I: A Search for Extended Ly-Alpha Nebular Emission Around 31 z>5.7 Quasars
• The LOFAR Two-Metre Sky Survey (LoTSS): VI. Optical identifications for the second data release
• Exploring AGN and Star Formation Activity of Massive Galaxies at Cosmic Noon
• The impact of modified gravity on the Sunyaev-Zel'dovich effect
• A Multiwavelength Study of ELAN Environments (AMUSE${}^2$). Mass budget, satellites spin alignment and gas infall in a massive $z\sim 3$ quasar host halo
• Discovery of a Lya emitting dark-cloud within z ~ 2.8 SMMJ02399-0136 system
• QSO MUSEUM II: Search for extended Ly$\alpha$ emission around eight $z\sim 3$ quasar pairs
• The luminosity-area relation of $z>2$ quasars' Ly$\alpha$ nebulae
• The miniJPAS Survey: Detection of double-core Lyα morphology of two high-redshift (z>3) QSOs
• Circumgalactic Ly$\alpha$ Nebulae in Overdense Quasar Pair Regions Observed with the Palomar Cosmic Web Imager

Cited by in corpus (1)

• GA-NIFS: AGN activity in a Lyα emitter within a triple-AGN system anchored by a passive galaxy at z=3