We report the discovery of a multiply lensed Lyman-α blob (LAB) behind the galaxy cluster AS1063 using the Multi Unit SpectroscopicExplorer (MUSE) on the Very Large Telescope (VLT). The background sourceis at z = 3.117 and is intrinsically faint compared to almost allpreviously reported LABs. We used our highly precise strong lensingmodel to reconstruct the source properties and we find an intrinsicluminosity of L_Lyα = 1.9 × 10^42 ergs^-1 extending to 33 kpc. We find that the LAB is associatedwith a group of galaxies and possibly a protocluster in agreement withprevious studies that find LABs in overdensities. In addition toLyman-α (Lyα) emission we find C iv He ii and O iii]ultraviolet (UV) emission lines arising from the centre of the nebula.We used the compactness of these lines in combination with the lineratios to conclude that the Lyα nebula is likely powered byembedded star formation. Resonant scattering of the Lyα photonsthen produces the extended shape of the emission. Thanks to the combinedpower of MUSE and strong gravitational lensing we are now able to probethe circumgalatic medium of sub-L_∗ galaxies at z ≈3.
Discovery of a faint star-forming multiply lensed Lyman-α blob
Mercurio A;
2016-01-01
Abstract
We report the discovery of a multiply lensed Lyman-α blob (LAB) behind the galaxy cluster AS1063 using the Multi Unit SpectroscopicExplorer (MUSE) on the Very Large Telescope (VLT). The background sourceis at z = 3.117 and is intrinsically faint compared to almost allpreviously reported LABs. We used our highly precise strong lensingmodel to reconstruct the source properties and we find an intrinsicluminosity of L_Lyα = 1.9 × 10^42 ergs^-1 extending to 33 kpc. We find that the LAB is associatedwith a group of galaxies and possibly a protocluster in agreement withprevious studies that find LABs in overdensities. In addition toLyman-α (Lyα) emission we find C iv He ii and O iii]ultraviolet (UV) emission lines arising from the centre of the nebula.We used the compactness of these lines in combination with the lineratios to conclude that the Lyα nebula is likely powered byembedded star formation. Resonant scattering of the Lyα photonsthen produces the extended shape of the emission. Thanks to the combinedpower of MUSE and strong gravitational lensing we are now able to probethe circumgalatic medium of sub-L_∗ galaxies at z ≈3.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
