2018/08/01 by D. Schaerer, Y. Izotov, Y. I. Izotov +9 · 1 citation
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Star Formation Studies #Emission spectrum #Equivalent width #Galaxies: Formation, Evolution, Phenomena #Galaxy #Hubble space telescope #Ion #Ionization #Metallicity #Photoionization #Physics #Population #Redshift #Reionization #Space Telescope Imaging Spectrograph #Spectral line #Star formation #astro-ph.GA
paper · pdf · doi:10.1051/0004-6361/201833823
published as A&A 616, L14 (2018) · 5 pages, 4 figures. Accepted for publication in A&A Letters
openalex publication_date 2018/08/01 · arxiv created 2018/08/09 · openalex created_date 2018/08/22 · arxiv updated 2018/08/29 · openalex updated_date 2026/08/05
We have obtained the first complete ultraviolet (UV) spectrum of a strong Lyman continuum (LyC) emitter at low redshift – the compact, low-metallicity, star-forming galaxy J1154+2443 – with a Lyman continuum escape fraction of 46% discovered recently. The Space Telescope Imaging Spectrograph spectrum shows strong Ly α and C III ] λ 1909 emission, as well as O III ] λ 1666. Our observations show that strong LyC emitters can have UV emission lines with a high equivalent width (e.g. EW(C III ]) = 11.7 ± 2.9 Å rest-frame), although their equivalent widths should be reduced due to the loss of ionizing photons. The intrinsic ionizing photon production efficiency of J1154+2443 is high, log( ξ 0 ion = 25.56 erg −1 Hz), comparable to that of other recently discovered z ~ 0.3−0.4 LyC emitters. Combining our measurements and earlier determinations from the literature, we find a trend of increasing ξ 0 ion with increasing C III ] λ 1909 equivalent width, which can be understood by a combination of decreasing stellar population age and metallicity. Simple ionization and density-bounded photoionization models can explain the main observational features including the UV spectrum of J1154+2443.