VLT/MUSE illuminates possible channels for Lyman continuum escape in the halo of SBS 0335-52E^⋆

¹ Department of Astronomy, Stockholm University, AlbaNova University Centre, 106 91 Stockholm, Sweden
e-mail: christian.herenz@astro.su.se
² Instituto de Astrofísica e Ciências do Espaço − Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
³ Department of Physics & Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105, USA

Received: 21 August 2017
Accepted: 2 October 2017

Abstract

We report on the discovery of ionised gas filaments in the circum-galactic halo of the extremely metal-poor compact starburst SBS 0335-052E in a 1.5 h integration with the MUSE integral-field spectrograph. We detect these features in Hα and [O iii] emission down to a limiting surface-brightness of 5 × 10^-19 erg s^-1 cm^-2 arcsec^-2. The filaments have projected diameters of 2.1 kpc and extend more than 9 kpc to the north and north-west from the main stellar body. We also detect extended nebular He ii λ4686 emission that brightens towards the north-west at the rim of a starburst driven super-shell. We also present a velocity field of the ionised gas. The filaments appear to connect seamlessly in velocity space to the kinematical disturbances caused by the shell. Similar to high-z star-forming galaxies, the ionised gas in this galaxy is dispersion dominated. We argue that the filaments were created via feedback from the starburst and that these ionised structures in the halo may act as escape channels for Lyman continuum radiation in this gas-rich system.