{"external_id":{"arxiv":["1805.11621"]},"status":"public","oa":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","acknowledgement":"JM acknowledges the award of a Huygens PhD fellowship from Leiden University. MG acknowledges support from NASA grant NNX17AK58G. APA, PhD::SPACE fellow, acknowledges support from the FCT through the fellowship PD/BD/52706/2014. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme IDs 294.A-5018, 098.A-0819, 099.A-0254 and 0100.A-0213. We are grateful for the excellent data-sets from the COSMOS and UltraVISTA survey teams. This research was supported by the Munich Institute for Astro- and Particle Physics (MIAPP) of the DFG cluster of excellence “Origin and Structure of the Universe”. We thank the referee for their comments that improved the paper. We also thank Christoph Behrens, Len Cowie, Koki Kakiichi, Peter Laursen, Charlotte Mason, Eros Vanzella, Lewis Weinberger and Johannes Zabl for discussions. We have benefited from the public available programming language Python, including the numpy, matplotlib, scipy and astropy packages (Hunter 2007; Astropy Collaboration 2013), the astronomical imaging tools Swarp (Bertin 2010) and ds9 and the Topcat analysis tool (Taylor 2013).","article_processing_charge":"No","month":"11","date_created":"2022-07-06T11:14:23Z","citation":{"apa":"Matthee, J. J., Sobral, D., Gronke, M., Paulino-Afonso, A., Stefanon, M., &#38; Röttgering, H. (2018). Confirmation of double peaked Lyα emission at z = 6.593: Witnessing a galaxy directly contributing to the reionisation of the universe. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href=\"https://doi.org/10.1051/0004-6361/201833528\">https://doi.org/10.1051/0004-6361/201833528</a>","chicago":"Matthee, Jorryt J, David Sobral, Max Gronke, Ana Paulino-Afonso, Mauro Stefanon, and Huub Röttgering. “Confirmation of Double Peaked Lyα Emission at z = 6.593: Witnessing a Galaxy Directly Contributing to the Reionisation of the Universe.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2018. <a href=\"https://doi.org/10.1051/0004-6361/201833528\">https://doi.org/10.1051/0004-6361/201833528</a>.","ista":"Matthee JJ, Sobral D, Gronke M, Paulino-Afonso A, Stefanon M, Röttgering H. 2018. Confirmation of double peaked Lyα emission at z = 6.593: Witnessing a galaxy directly contributing to the reionisation of the universe. Astronomy &#38; Astrophysics. 619, A136.","ieee":"J. J. Matthee, D. Sobral, M. Gronke, A. Paulino-Afonso, M. Stefanon, and H. Röttgering, “Confirmation of double peaked Lyα emission at z = 6.593: Witnessing a galaxy directly contributing to the reionisation of the universe,” <i>Astronomy &#38; Astrophysics</i>, vol. 619. EDP Sciences, 2018.","short":"J.J. Matthee, D. Sobral, M. Gronke, A. Paulino-Afonso, M. Stefanon, H. Röttgering, Astronomy &#38; Astrophysics 619 (2018).","mla":"Matthee, Jorryt J., et al. “Confirmation of Double Peaked Lyα Emission at z = 6.593: Witnessing a Galaxy Directly Contributing to the Reionisation of the Universe.” <i>Astronomy &#38; Astrophysics</i>, vol. 619, A136, EDP Sciences, 2018, doi:<a href=\"https://doi.org/10.1051/0004-6361/201833528\">10.1051/0004-6361/201833528</a>.","ama":"Matthee JJ, Sobral D, Gronke M, Paulino-Afonso A, Stefanon M, Röttgering H. Confirmation of double peaked Lyα emission at z = 6.593: Witnessing a galaxy directly contributing to the reionisation of the universe. <i>Astronomy &#38; Astrophysics</i>. 2018;619. doi:<a href=\"https://doi.org/10.1051/0004-6361/201833528\">10.1051/0004-6361/201833528</a>"},"_id":"11508","author":[{"last_name":"Matthee","id":"7439a258-f3c0-11ec-9501-9df22fe06720","full_name":"Matthee, Jorryt J","first_name":"Jorryt J","orcid":"0000-0003-2871-127X"},{"last_name":"Sobral","full_name":"Sobral, David","first_name":"David"},{"first_name":"Max","full_name":"Gronke, Max","last_name":"Gronke"},{"last_name":"Paulino-Afonso","first_name":"Ana","full_name":"Paulino-Afonso, Ana"},{"full_name":"Stefanon, Mauro","first_name":"Mauro","last_name":"Stefanon"},{"first_name":"Huub","full_name":"Röttgering, Huub","last_name":"Röttgering"}],"doi":"10.1051/0004-6361/201833528","abstract":[{"lang":"eng","text":"Distant luminous Lyman-α emitters (LAEs) are excellent targets for spectroscopic observations of galaxies in the epoch of reionisation (EoR). We present deep high-resolution (R = 5000) VLT/X-shooter observations, along with an extensive collection of photometric data of COLA1, a proposed double peaked LAE at z = 6.6. We rule out the possibility that COLA1’s emission line is an [OII] doublet at z = 1.475 on the basis of i) the asymmetric red line-profile and flux ratio of the peaks (blue/red=0.31 ± 0.03) and ii) an unphysical [OII]/Hα ratio ([OII]/Hα >  22). We show that COLA1’s observed B-band flux is explained by a faint extended foreground LAE, for which we detect Lyα and [OIII] at z = 2.142. We thus conclude that COLA1 is a real double-peaked LAE at z = 6.593, the first discovered at z >  6. COLA1 is UV luminous (M1500 = −21.6 ± 0.3), has a high equivalent width (EW0,Lyα = 120−40+50 Å) and very compact Lyα emission (r50,Lyα = 0.33−0.04+0.07 kpc). Relatively weak inferred Hβ+[OIII] line-emission from Spitzer/IRAC indicates an extremely low metallicity of Z <  1/20 Z⊙ or reduced strength of nebular lines due to high escape of ionising photons. The small Lyα peak separation of 220 ± 20 km s−1 implies a low HI column density and an ionising photon escape fraction of ≈15 − 30%, providing the first direct evidence that such galaxies contribute actively to the reionisation of the Universe at z >  6. Based on simple estimates, we find that COLA1 could have provided just enough photons to reionise its own ≈0.3 pMpc (2.3 cMpc) bubble, allowing the blue Lyα line to be observed. However, we also discuss alternative scenarios explaining the detected double peaked nature of COLA1. Our results show that future high-resolution observations of statistical samples of double peaked LAEs at z >  5 are a promising probe of the occurrence of ionised regions around galaxies in the EoR."}],"article_number":"A136","publication_status":"published","publication":"Astronomy & Astrophysics","extern":"1","type":"journal_article","date_updated":"2022-07-19T09:32:08Z","volume":619,"publication_identifier":{"issn":["0004-6361"],"eissn":["1432-0746"]},"day":"19","year":"2018","article_type":"original","publisher":"EDP Sciences","date_published":"2018-11-19T00:00:00Z","keyword":["Space and Planetary Science","Astronomy and Astrophysics","galaxies: high-redshift / galaxies: formation / dark ages / reionization / first stars / techniques: spectroscopic / intergalactic medium"],"quality_controlled":"1","scopus_import":"1","title":"Confirmation of double peaked Lyα emission at z = 6.593: Witnessing a galaxy directly contributing to the reionisation of the universe","main_file_link":[{"url":"https://arxiv.org/abs/1805.11621","open_access":"1"}],"oa_version":"Published Version","language":[{"iso":"eng"}],"intvolume":"       619"}