CR7 is among the most luminous Ly α emitters (LAEs) known at z = 6.6 and consists of at least three UV components that are surrounded by Ly α emission. Previous studies have suggested that it may host an extreme ionizing source. Here, we present deep integral field spectroscopy of CR7 with VLT/Multi Unit Spectroscopic Explorer (MUSE). We measure extended emission with a similar halo scale length as typical LAEs at z ≈ 5. CR7's Ly α halo is clearly elongated along the direction connecting the multiple components, likely tracing the underlying gas distribution. The Ly α emission originates almost exclusively from the brightest UV component, but we also identify a faint kinematically distinct Ly α emitting region nearby a fainter component. Combined with new near-infrared data, the MUSE data show that the rest-frame Ly α equivalent width (EW) is ≈100 Å. This is a factor 4 higher than the EW measured in low-redshift analogues with carefully matched Ly α profiles (and thus arguably H i column density), but this EW can plausibly be explained by star formation. Alternative scenarios requiring active galactic nucleus (AGN) powering are also disfavoured by the narrower and steeper Ly α spectrum and much smaller IR to UV ratio compared to obscured AGN in other Ly α blobs. CR7's Ly α emission, while extremely luminous, resembles the emission in more common LAEs at lower redshifts very well and is likely powered by a young metal-poor starburst.
Matthee, J., Pezzulli, G., Mackenzie, R., Cantalupo, S., Kusakabe, H., Leclercq, F., et al. (2020). The nature of CR7 revealed with MUSE: A young starburst powering extended Ly α emission at z = 6.6. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 498(2), 3043-3059.
|Citazione:||Matthee, J., Pezzulli, G., Mackenzie, R., Cantalupo, S., Kusakabe, H., Leclercq, F., et al. (2020). The nature of CR7 revealed with MUSE: A young starburst powering extended Ly α emission at z = 6.6. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 498(2), 3043-3059.|
|Tipo:||Articolo in rivista - Articolo scientifico|
|Carattere della pubblicazione:||Scientifica|
|Presenza di un coautore afferente ad Istituzioni straniere:||Si|
|Titolo:||The nature of CR7 revealed with MUSE: A young starburst powering extended Ly α emission at z = 6.6|
|Autori:||Matthee, J; Pezzulli, G; Mackenzie, R; Cantalupo, S; Kusakabe, H; Leclercq, F; Sobral, D; Richard, J; Wisotzki, L; Lilly, S; Boogaard, L; Marino, R; Maseda, M; Nanayakkara, T|
|Data di pubblicazione:||2020|
|Rivista:||MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1093/mnras/staa2550|
|Appare nelle tipologie:||01 - Articolo su rivista|