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Paper: Resolved Spectroscopy of a Gravitationally Lensed L* Lyman Break Galaxy at z ∼ 5: Evidence for a Starburst-Driven, Galactic-Scale Bi-Polar Outflow
Volume: 379, Cosmic Frontiers
Page: 226
Authors: Swinbank, M.
Abstract: We exploit the gravitational potential of a massive, rich cluster as a natural magnifying glass to study the internal properties of the highly magnified galaxy at z=4.88. Using high resolution HST imaging we construct a detailed mass model and, together with optical (VIMOS) and near-infrared (SINFONI) Integral Field Spectroscopy, we have mapped the source-frame morphology of the lensed galaxy behind galaxy cluster RCS0224-002 on 200pc scales to find an ~L Lyman-break galaxy with a dynamical mass of 1.01010M within 2 kpc and infer an integrated star-formation rate of just 122M yr−1. By combing the spatially resolved velocities from the [OII] and Lyα emission and UV ISM absorption lines we suggest that this galaxy is surrounded by a galacticscale bi-polar outflow which has recently burst out of the system and is escaping at a speed of ~500 kms−1. The geometry and velocity of the outflow suggests that the ejected material is travelling far faster than escape velocity and we estimate that it will travel at least 1Mpc (comoving) before eventually stalling. The enriched, outflowing material is therefore efficient at expelling baryons which are likely to subsequently play no further part in the star-formation history of this galaxy, but rather will pollute the IGM in a volume of at least 3Mpc3.
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