A giant Ly$\alpha$ nebula in the core of an X-ray cluster at $z=1.99$: implications for early energy injection

摘要: We present the discovery of a giant $\gtrsim$100~kpc Ly$\alpha$ nebula detected in core X-ray emitting cluster CL~J1449+0856 at $z=1.99$ through Keck/LRIS narrow-band imaging. This detection extends known relation between nebulae and overdense regions Universe to dense $5-7\times10^{13}$ M$_{\odot}$ cluster. The most plausible candidates power are two Chandra-detected AGN host members, while cooling from phase cosmological cold flows disfavored primarily because high luminosity ratio ($L_{\mathrm{Ly\alpha}}/L_{\mathrm{X}} \approx0.3$, $\gtrsim10-1000\times$ higher than local cool-core clusters) by current modeling. Given physical conditions Ly$\alpha$-emitting gas possible interplay with phase, we argue that would be short-lived ($\lesssim10$ Myr) if not continuously replenished rate $\gtrsim1000$ yr$^{-1}$. investigate possibility galaxies supply required outflows show their total mass outflow matches replenishment necessary sustain nebula. scenario directly implies extraction energy its deposition surrounding intracluster medium, as explain thermodynamic properties clusters. estimate an injection order $\thickapprox2$ keV per particle medium over $2$ Gyr interval. In our baseline calculation provide up $85$% injected 2/3 mass, rest is supplied supernovae-driven winds.