# VIMOS-VLT spectroscopy of the giant Ly-alpha nebulae associated with three z~2.5 radio galaxies

## TL;DR

This study investigates the morphology and kinematics of giant Ly-alpha nebulae around three z~2.5 radio galaxies using VLT/VIMOS spectroscopy, revealing varied structures, alignment with radio axes, and evidence for infall in one case.

## Contribution

It provides detailed integral field spectroscopic analysis of giant Ly-alpha nebulae, introduces an infall model for their properties, and reports a unique relaxed kinematic nebula at high redshift.

## Key findings

- Nebulae are aligned with radio axes within 30 degrees.
- Ly-alpha luminosities range from 0.3 to 3.4 x 10^44 erg/s.
- One nebula shows relaxed kinematics with FWHM<300 km/s.

## Abstract

The morphological and spectroscopic properties of the giant (>60 kpc) Ly-alpha nebulae associated with three radio galaxies at z~2.5 (MRC 1558-003, MRC 2025-218 and MRC 0140-257) have been investigated using integral field spectroscopic data obtained with VIMOS on VLT. The morphologies are varied. The nebula of one source has a centrally peaked, rounded appearance. In the other two objects, it consists of two spatial components. The three nebulae are aligned with the radio axis within <30 deg. The total Ly-alpha luminosities are in the range (0.3-3.4) x 1e44 erg s-1. The Ly-alpha spectral profile shows strong variation through the nebulae, with FWHM values in the range ~400-1500 km s-1 and velocity shifts V~120-600 km s-1. We present an infall model which can explain successfully most Ly-alpha morphological and spectroscopic properties of the nebula associated with MRC 1558-003. This adds further support to our previous conclusion that the _quiescent_ giant nebulae associated with this and other high redshift powerful radio galaxies are in infall. A problem for this model is the difficulty to reproduce the large Ly-alpha FWHM values. We have discovered a giant (~85 kpc) Ly-alpha nebula associated with the radio galaxy MRC 0140-257 at z=2.64. It shows strikingly relaxed kinematics (FWHM< 300 km s-1 and V<120 km s-1), unique among high z (>2) radio galaxies.