Illuminating gas inflows/outflows in the MUSE deepest fields: Lyα nebulae around forming galaxies at z ≃ 3.3
Articolo
Data di Pubblicazione:
2017
Citazione:
Illuminating gas inflows/outflows in the MUSE deepest fields: Lyα nebulae around forming galaxies at z ≃ 3.3 / E. Vanzella, I. Balestra, M. Gronke, W. Karman, G.B. Caminha, M. Dijkstra, P. Rosati, S. De Barros, K. Caputi, C. Grillo, P. Tozzi, M. Meneghetti, A. Mercurio, R. Gilli. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 465:4(2017), pp. 3803-3816. [10.1093/mnras/stw2442]
Abstract:
We report the identification of extended Lyα nebulae at z ≃ 3.3 in the Hubble Ultra Deep Field (HUDF, ≃40 kpc × 80 kpc) and behind the Hubble Frontier Field galaxy clusterMACSJ0416 (≃40 kpc), spatially associated with groups of star-forming galaxies. VLT/MUSE integral field spectroscopy reveals a complex structure with a spatially varying double-peaked Lyα emission. Overall, the spectral profiles of the two Lyα nebulae are remarkably similar, both showing a prominent blue emission, more intense and slightly broader than the red peak. From the first nebula, located in the HUDF, no X-ray emission has been detected, disfavouring the possible presence of active galactic nuclei. Spectroscopic redshifts have been derived for 11 galaxies within 2 arcsec from the nebula and spanning the redshift range 1.037 < z < 5.97. The second nebula, behind MACSJ0416, shows three aligned star-forming galaxies plausibly associated with the emitting gas. In both systems, the associated galaxies reveal possible intense rest-frame-optical nebular emissions lines [O III] λλ4959, 5007+Hβ with equivalent widths as high as 1500 Å rest frame and star formation rates ranging from a few to tens of solar masses per year. A possible scenario is that of a group of young, star-forming galaxies emitting ionizing radiation that induces Lyα fluorescence, therefore revealing the kinematics of the surrounding gas. Also Lyα powered by star formation and/or cooling radiation may resemble the double-peaked spectral properties and the morphology observed here. If the intense blue emission is associated with inflowing gas, then we may be witnessing an early phase of galaxy or a proto-cluster (or group) formation.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Galaxies: distances and redshifts; Galaxies: evolution; Galaxies: starburst; Gravitational lensing: strong; Radiative transfer; Astronomy and Astrophysics; Space and Planetary Science
Elenco autori:
E. Vanzella, I. Balestra, M. Gronke, W. Karman, G.B. Caminha, M. Dijkstra, P. Rosati, S. De Barros, K. Caputi, C. Grillo, P. Tozzi, M. Meneghetti, A. Mercurio, R. Gilli
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