Discovery of a faint, star-forming, multiply lensed, Lyman-α blob

Journal
Date Issued
2016
Author(s)
Caminha, G. B.
•
Karman, W.
•
Rosati, P.
•
Caputi, K. I.
•
Arrigoni Battaia, F.
•
Balestra, I.
•
Grillo, C.
•
•
•
DOI
Description
G.B.C. is supported by the CAPES-ICRANet program grant BEX 13946/13-7. C.G. acknowledges support by VILLUM FONDEN Young Investigator Programme grant 10123. We acknowledge financial support from PRIN-INAF 2014 1.05.01.94.02. This work made use of the CHE cluster, managed and funded by ICRA/CBPF/MCTI, with financial support from FINEP (grant 01.07.0515.00 from CT-INFRA−01/2006) and FAPERJ (grants E-26/171.206/2006 and E-26/110.516/2012). This work also made use of data gathered under the ESO programmes 186.A-0798 and 60.A-9345(A).
Abstract
We report the discovery of a multiply lensed Lyman-α blob (LAB) behind the galaxy cluster AS1063 using the Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope (VLT). The background source is at z = 3.117 and is intrinsically faint compared to almost all previously reported LABs. We used our highly precise strong lensing model to reconstruct the source properties, and we find an intrinsic luminosity of LLyα = 1.9 × 1042 erg s-1, extending to 33 kpc. We find that the LAB is associated with a group of galaxies, and possibly a protocluster, in agreement with previous studies that find LABs in overdensities. In addition to Lyman-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 line ratios to conclude that the Lyα nebula is likely powered by embedded star formation. Resonant scattering of the Lyα photons then produces the extended shape of the emission. Thanks to the combined power of MUSE and strong gravitational lensing, we are now able to probe the circumgalatic medium of sub-L∗ galaxies at z ≈ 3.
Volume
595
Start page
A100
Uri
Url
Issn Identifier
0004-6361
Ads BibCode
2016A&A...595A.100C
Rights
open.access
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