J1154+2443: a low-redshift compact star-forming galaxy with a 46 per cent leakage of Lyman continuum photons
By Y. Izotov, Daniel Schaerer, G. Worseck, N. Guseva, T. Thuan, A. Verhamme, I. Orlitová, K. Observatory, Ukrainian National Academy of Sciences, Kyiv and 28 more. 2017
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We report the detection of the Lyman continuum (LyC) radiation of the compact star-forming galaxy (SFG) J1154+2443 observed with the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope. This galaxy, at a redshift of z=0.3690, is characterized by a high emission-line flux ratio O32=[OIII]5007/[OII]3727=11.5. The escape fraction of the LyC radiation fesc(LyC) in this galaxy is 46 per cent, the highest value found so far in low-redshift SFGs and one of the highest values found in galaxies at any redshift. The narrow double-peaked Lya emission line is detected in the spectrum of J1154+2443 with a separation between the peaks Vsep of 199 km/s, one of the lowest known for Lya-emitting galaxies, implying a high fesc(Lya). Comparing the extinction-corrected Lya/Hb flux ratio with the case B value we find fesc(Lya) = 98 per cent. Our observations, combined with previous detections in the literature, reveal an increase of O32 with increasing fesc(LyC). We also find a tight anticorrelation between fesc(LyC) and Vsep. The surface brightness profile derived from the COS acquisition image reveals a bright star-forming region in the centre and an exponential disc in the outskirts with a disc scale length alpha=1.09 kpc. J1154+2443, compared to other known low-redshift LyC leakers, is characterized by the lowest metallicity, 12+logO/H=7.65+/-0.01, the lowest stellar mass M*=10^8.20 Msun, a similar star formation rate SFR=18.9 Msun/yr and a high specific SFR of 1.2x10^-7 yr^-1.
Subfields: Astronomy and Astrophysics, Instrumentation
View Paper: https://www.semanticscholar.org/paper/4c5ca6b11d26d5cb68fb1ce0d6bbb24f197d4d44
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Citations in the corpus
- Conditions for Reionizing the Universe with a Low Galaxy Ionizing Photon Escape Fraction (2019, background): “At very low redshifts, while Schaerer et al. (2016) found log ξion∼25.1–25.5 for a sample of five Lyman continuum leaking galaxies at z∼0.3, Izotov et al. (2017) found that this quantity is heavily dependent on the assumed star formation history.”
- Rapid Reionization by the Oligarchs: The Case for Massive, UV-bright, Star-forming Galaxies with High Escape Fractions (2019, background): “The campaigns targeting Green Peas at z∼0.3 with Hubble Space Telescope (HST)/COS have proven remarkably efficient (boasting a 100% success rate for LyC detection; Izotov et al. 2016b, 2018b).”
- Low-redshift Lyman continuum leaking galaxies with high [O iii]/[O ii] ratios (2018, methodology): “The details of both methods are described by Izotov et al. (2018).”
- Evolution of the AGN UV luminosity function from redshift 7.5 (2018, background): “Alternatively, it may be possible to balance the ionization rate deficit by the contribution from low-redshift LyC-leaking galaxies (Izotov et al. 2016, 2018a,b)”