Mapping the dynamics of a giant Ly alpha halo at z=4.1 with MUSE: the energetics of a large-scale AGN-driven outflow around a massive, high-redshift galaxy

作者：Swinbank A M^*; Vernet J D R; Smail Ian; De Breuck C; Bacon R; Contini T; Richard J; Roettgering H J A; Urrutia T; Venemans B

来源：Monthly Notices of the Royal Astronomical Society, 2015, 449(2): 1298-1308.

DOI：10.1093/mnras/stv366

• galaxies: evolution
• galaxies: high-redshift

We present Multi Unit Spectroscopic Explorer (MUSE) integral field unit spectroscopic observations of the similar to 150 kpc Ly alpha halo around the z = 4.1 radio galaxy TN J1338-1942. This 9-h observation maps the full two-dimensional kinematics of the Ly alpha emission across the halo, which shows a velocity gradient of Delta v similar to 700 km s(-1) across 150 kpc in projection, and also identified two absorption systems associated with the Ly alpha emission from the radio galaxy. Both absorbers have high covering fractions (similar to 1) spanning the full similar to 150 x 80 kpc2 extent of the halo. The stronger and more blueshifted absorber (Delta v similar to-1200 km s(-1) from the systemic) has dynamics that mirror that of the underlying halo emission and we suggest that this high column material (n(H I) similar to 1019.4 cm(-2)), which is also seen in CIV absorption, represents an outflowing shell that has been driven by the active galactic nuclei (AGN) or the star formation within the galaxy. The weaker (n(H I) similar to 10(14) cm(-2)) and less blueshifted (Delta v similar to -500 km s(-1)) absorber most likely represents material in the cavity between the outflowing shell and the Ly alpha halo. We estimate that the mass in the shell must be similar to 10(10) M-circle dot - a significant fraction of the interstellar medium from a galaxy at z = 4. The large scales of these coherent structures illustrate the potentially powerful influence of AGN feedback on the distribution and energetics of material in their surroundings. Indeed, the discovery of high-velocity (similar to 1000 km s(-1)), group-halo-scale (i.e. > 150 kpc) and mass-loaded winds in the vicinity of the central radio source is in agreement with the requirements of models that invoke AGN-driven outflows to regulate star formation and black hole growth in massive galaxies.

• 出版日期2015-5-11