Escape fraction of ionizing photons from high-redshift galaxies in cosmological SPH simulations

By H. Yajima, Jun-Hwan Choi, Kentaro Nagamine. 2010

171 citations recorded by the source corpus.

Combing the three-dimensional radiative transfer (RT) calculation and cosmological smoothed particle hydrodynamics (SPH) simulations, we study the escape fraction of ionizing photons (f esc ) of high-redshift galaxies at z = 3-6. Our simulations cover the halo mass range of M h = 10 9 -10 12 M ⊙ . We post-process several hundred simulated galaxies with the Authentic Radiative Transfer (ART) code to study the halo mass dependence of f esc . In this paper, we restrict ourselves to the transfer of stellar radiation from local stellar population in each dark matter halo. We find that the average f esc steeply decreases as the halo mass increases, with a large scatter for the lower-mass haloes. The low-mass haloes with M h ∼ 10 9 M ⊙ have large values of f esc (with an average of ∼0.4), whereas the massive haloes with M h ∼ 10 11 M ⊙ show small values of f esc (with an average of ∼0.07). This is because in our simulations, the massive haloes show more clumpy structure in gas distribution, and the star-forming regions are embedded inside these clumps, making it more difficult for the ionizing photons to escape. On the other hand, in low-mass haloes, there are often conical regions of highly ionized gas due to the shifted location of young star clusters from the centre of dark matter halo, which allows the ionizing photons to escape more easily than in the high-mass haloes. By counting the number of escaped ionizing photons, we show that the star-forming galaxies can ionize the intergalactic medium at z = 3-6. The main contributor to the ionizing photons is the haloes with M h ≲ 10 10 M ⊙ owing to their high f esc . The large dispersion in f esc suggests that there may be various sizes of H II bubbles around the haloes even with the same mass in the early stages of reionization. We also examine the effect of UV background radiation field on f esc using simple, four different treatments of UV background.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/cc482ed5d5d162c5ca98ed2e611aaa5fc6442574

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Citations in the corpus

Inferring the astrophysics of reionization and cosmic dawn from galaxy luminosity functions and the 21-cm signal (2018, background): “As mentioned earlier, we expect αesc to be negative as SNe can more easily evacuate low column density channels from shallower potential wells (e.g. Razoumov & Sommer-Larsen 2010; Yajima et al. 2011; Ferrara & Loeb 2013; Paardekooper et al. 2015; Xu et al. 2016; Kimm et al. 2017; Katz et al. 2018).”
Using Lyman-α to detect galaxies that leak Lyman continuum (2014, background): “…from LAEs than from LBGs. Theorists have repeatedly shown that LyC leakage generally increases at lower galaxy masses (e.g. Ferrara & Loeb 2013; Yajima et al. 2011; Wise & Cen 2009), which superficially seems to be consitent with the stronger LyC leakage found from Article published by EDP…”
Concordance models of reionization: implications for faint galaxies and escape fraction evolution (2012, background): “Another possibility is that faint galaxies may typically have higher escape fraction than more massive galaxies (e.g. Yajima et al. 2011), in which case the larger relative abundance of faint galaxies at high redshift would result in an increase in the population-averaged escape fraction.”
Ubiquitous seeding of supermassive black holes by direct collapse (2012, background): “Recent studies (Wise & Cen 2009; Yajima et al. 2011; Paardekooper et al. 2011) have shown that that the escape fraction for UV photons could vary with the parent halo mass, however, the precise values of LW escape fractions from haloes is still unclear.”
GALAXY PROPERTIES AND UV ESCAPE FRACTIONS DURING THE EPOCH OF REIONIZATION: RESULTS FROM THE RENAISSANCE SIMULATIONS (2016, background): “…the photon budget in reionization models and has attracted much attention from numerical studies (e.g., Gnedin et al. 2008; Wise & Cen 2009; Razoumov & Sommer-Larsen 2010; Yajima et al. 2011; Ferrara & Loeb 2013; Paardekooper et al. 2013; Kimm & Cen 2014; Wise et al. 2014; Ma et al. 2015).”
Cosmic Dawn (CoDa): the first radiation-hydrodynamics simulation of reionization and galaxy formation in the Local Universe (2015, background): “In this case, fesc,? can span a wide range of values, from almost 0 to about 40%, as shown by high resolution simulations (Wise & Cen 2009; Razoumov & Sommer-Larsen 2010; Yajima et al. 2011; Wise et al. 2014).”
THE SPECTRAL EVOLUTION OF THE FIRST GALAXIES. I. JAMES WEBB SPACE TELESCOPE DETECTION LIMITS AND COLOR CRITERIA FOR POPULATION III GALAXIES (2011, background): “Simulations predict that the amount of Lyman continuum escape may be a function of dark halo mass (Gnedin et al. 2008; Razoumov & Sommer-Larsen 2010; Yajima et al. 2011), but the likely escape fraction and its exact mass dependence remains controversial.”
ESCAPE FRACTION OF IONIZING PHOTONS DURING REIONIZATION: EFFECTS DUE TO SUPERNOVA FEEDBACK AND RUNAWAY OB STARS (2014, background): “In this regard, one may find it reconcilable that results from cosmological simulations with limited resolutions (e.g.,Fujita et al. 2003; Razoumov & Sommer-Larsen 2010; Yajima et al. 2011) often give discrepant results.”
Detection of high Lyman continuum leakage from four low-redshift compact star-forming galaxies (2016, background): “…galaxies at the epoch of cosmic reionization predict that the least massive galaxies have the highest fesc(LyC) (e.g Razoumov & Sommer-Larsen 2010; Yajima et al. 2011; Wise et al. 2014), while other studies find relatively low escape fractions, fesc(LyC) ≈ 5 %, with no strong dependence on galaxy…”
Large Ly α opacity fluctuations and low CMB τ in models of late reionization with large islands of neutral hydrogen extending to z < 5.5 (2018, background): “…to the evolution of the escape fraction of ionizing photons from galaxies, possibly due to changes in morphology, stellar populations, and dust con- tent of these galaxies (Rosdahl et al. 2018; Trebitsch et al. 2017; Kimm et al. 2017; Paardekooper et al. 2015; Kimm & Cen 2014; Yajima et al. 2011).”
Escape of Lyman continuum radiation from local galaxies - Detection of leakage from the young starburst Tol 1247-232 (2013, background): “Most models also predict that low-mass galaxies should be much more efficient in letting out the ionizing photons into the intergalactic medium than more massive galaxies (Ricotti & Shull 2000; Razoumov & SommerLarsen 2010; Yajima et al. 2011).”
The First Billion Years project: the impact of stellar radiation on the co-evolution of Populations II and III (2012, background): “…clumping factor C of the IGM to a typical value reported by Pawlik et al. (2009), and fesc is normalized to a typical value found in cosmological radiative transfer simulations (e.g. Ricotti & Shull 2000; Wise & Cen 2009; Razoumov & Sommer-Larsen 2010; Paardekooper et al. 2011; Yajima et al. 2011).”
Feedback-regulated star formation and escape of LyC photons from mini-haloes during reionization (2016, background): “A negative dependence on halo mass in the atomic-cooling regime is also found in other large cosmological simulations based on post-processing (Yajima et al. 2011; Paardekooper et al. 2013).”