We report on the serendipitous discovery of a z = 4.0, M1500 = -22.20 star-forming galaxy (Ion3) showing copious Lyman continuum (LyC) leakage (~60 per cent escaping), a remarkable multiple peaked Ly a emission, and significant Ly a radiation directly emerging at the resonance frequency. This is the highest redshift confirmed LyC emitter in which the ionizing and Ly α radiation possibly share a common ionized channel (with NHI < 1017.2cm-2). Ion3 is spatially resolved, it shows clear stellar winds signatures like the P-Cygni NVλ1240 profile, and has blue ultraviolet continuum (β = -2.5 ± 0.25, Fλ~ λβ) with weak low-ionization interstellar metal lines. Deep VLT/HAWKI Ks and Spitzer/IRAC 3.6 and 4.5μm imaging show a clear photometric signature of the Hα line with equivalent width of 1000Årest-frame emerging over a flat continuum (Ks-4.5μm ≃ 0). From the SED fitting, we derive a stellar mass of 1.5 × 109M⊙, SFR of 140 M⊙yr-1and age of ~10 Myr, with a low dust extinction, E(B - V) ≲ 0.1, placing the source in the starburst region of the SFR-M* plane. Ion3 shows similar properties of another LyC emitter previously discovered (z = 3.21, Ion2, Vanzella et al. 2016). Ion3 (and Ion2) represents ideal high-redshift reference cases to guide the search for reionizing sources at z > 6.5 with JWST.
Direct Lyman continuum and Ly α escape observed at redshift 4 / E. Vanzella, M. Nonino, G. Cupani, M. Castellano, E. Sani, M. Mignoli, F. Calura, M. Meneghetti, R. Gilli, A. Comastri, A. Mercurio, G.B. Caminha, K. Caputi, P. Rosati, C. Grillo, S. Cristiani, I. Balestra, A. Fontana, M. Giavalisco. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. LETTERS. - ISSN 1745-3925. - 476:1(2018 May 01), pp. L15-L19. [10.1093/mnrasl/sly023]
Direct Lyman continuum and Ly α escape observed at redshift 4
C. Grillo;
2018
Abstract
We report on the serendipitous discovery of a z = 4.0, M1500 = -22.20 star-forming galaxy (Ion3) showing copious Lyman continuum (LyC) leakage (~60 per cent escaping), a remarkable multiple peaked Ly a emission, and significant Ly a radiation directly emerging at the resonance frequency. This is the highest redshift confirmed LyC emitter in which the ionizing and Ly α radiation possibly share a common ionized channel (with NHI < 1017.2cm-2). Ion3 is spatially resolved, it shows clear stellar winds signatures like the P-Cygni NVλ1240 profile, and has blue ultraviolet continuum (β = -2.5 ± 0.25, Fλ~ λβ) with weak low-ionization interstellar metal lines. Deep VLT/HAWKI Ks and Spitzer/IRAC 3.6 and 4.5μm imaging show a clear photometric signature of the Hα line with equivalent width of 1000Årest-frame emerging over a flat continuum (Ks-4.5μm ≃ 0). From the SED fitting, we derive a stellar mass of 1.5 × 109M⊙, SFR of 140 M⊙yr-1and age of ~10 Myr, with a low dust extinction, E(B - V) ≲ 0.1, placing the source in the starburst region of the SFR-M* plane. Ion3 shows similar properties of another LyC emitter previously discovered (z = 3.21, Ion2, Vanzella et al. 2016). Ion3 (and Ion2) represents ideal high-redshift reference cases to guide the search for reionizing sources at z > 6.5 with JWST.File | Dimensione | Formato | |
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