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

Hidenobu Yajima (Penn State); Jun-Hwan Choi (UNLV); Kentaro Nagamine (UNLV)

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

Hidenobu Yajima (Penn State), Jun-Hwan Choi (UNLV), Kentaro Nagamine (UNLV)

Cosmology and Nongalactic Astrophysics · Submitted 17 Feb 2010

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim By counting the number of escaped ionizing photons, we show that the star-forming galaxies can ionize the intergalactic medium at z=3-6.

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arXiv ID1002.3346 (version 3)

Pith IDBU6GOV55, Pith's permanent record of this paper and its review

CitationHidenobu Yajima (Penn State), Jun-Hwan Choi (UNLV), Kentaro Nagamine (UNLV). "Escape fraction of ionizing photons from high-redshift galaxies in cosmological SPH simulations." arXiv:1002.3346 (2010). https://pith.science/paper/BU6GOV55

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The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

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What the abstract itself states, as probabilities: claims first 0.02 · states limitation 0.91 · human participants 0.01 · controlled comparison 0.13 · randomized assignment 0.01 · states quantitative result 0.99 · compares with prior results 0.07 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v3. Results and the main claim are underlined; show every role.

Combing the three-dimensional radiative transfer (RT) calculation and cosmological 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_sun. We postprocess 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_sun have large values of f_esc (with an average of ~ 0.4), whereas the massive haloes with M_h ~ 10^11 M_sun 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 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 center 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_sun owing to their high f_esc. The large dispersion in f_esc suggests that there may be various sizes of H{\sc 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 treatment of UV background.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	Combing the three-dimensional radiative transfer (RT) calculation and cosmological SPH simulations, we study the escape fraction of ionizing photons (f_esc) of high-redshift galaxies at z=3-6.	contribution 0.92	0.95	0.04	asserted 0.72
s1	Our simulations cover the halo mass range of M_h = 10^9 - 10^12 M_sun.	method 0.90	0.87	0.02	asserted 1.00
s2	We postprocess several hundred simulated galaxies with the Authentic Radiative Transfer (ART) code to study the halo mass dependence of f_esc.	method 0.99	0.95	0.02	asserted 0.87
s3	In this paper, we restrict ourselves to the transfer of stellar radiation from local stellar population in each dark matter halo.	limitation 0.97	0.80	0.02	asserted 0.91
s4	We find that the average f_esc steeply decreases as the halo mass increases, with a large scatter for the lower mass haloes.	result 1.00	0.97	0.68	asserted 1.00
s5	The low mass haloes with M_h ~ 10^9 M_sun have large values of f_esc (with an average of ~ 0.4), whereas the massive haloes with M_h ~ 10^11 M_sun show small values of f_esc (with an average of ~ 0.07).	result 1.00	0.97	0.31	asserted 1.00
s6	This is because in our simulations, the massive haloes show more clumpy structure in gas distribution, and star-forming regions are embedded inside these clumps, making it more difficult for the ionizing photons to escape.	interpretation 1.00	0.93	0.07	asserted 1.00
s7	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 center of dark matter halo, which allows the ionizing photons to escape more easily than in the high-mass haloes.	interpretation 0.99	0.87	0.06	asserted 0.99
s8	By counting the number of escaped ionizing photons, we show that the star-forming galaxies can ionize the intergalactic medium at z=3-6.	result 0.99	0.96	0.34	asserted 1.00
s9	The main contributor to the ionizing photons is the haloes with M_h < 10^10 M_sun owing to their high f_esc.	result 0.89	0.94	0.22	asserted 1.00
s10	The large dispersion in f_esc suggests that there may be various sizes of H{\sc ii} bubbles around the haloes even with the same mass in the early stages of reionization.	interpretation 0.98	0.85	0.06	hedged possibility 1.00
s11	We also examine the effect of UV background radiation field on f_esc using simple, four different treatment of UV background.	method 0.67	0.94	0.02	asserted 0.84

What kind of paper the classifier reports this is: simulation study 1.00 · evidence from simulation or computation 1.00.

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arXiv listing abstract v3

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full text
figures and tables
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Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

The paper

Original abstract

Combing the three-dimensional radiative transfer (RT) calculation and cosmological 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_sun. We postprocess 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_sun have large values of f_esc (with an average of ~ 0.4), whereas the massive haloes with M_h ~ 10^11 M_sun 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 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 center 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_sun owing to their high f_esc. The large dispersion in f_esc suggests that there may be various sizes of H{\sc 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 treatment of UV background.

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References

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Cited by 2 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

The THESAN-ZOOM project: the delayed rise of Lyman continuum escape fractions in bursty high-redshift galaxies
astro-ph.GA 2026-10 conditional novelty 7.0 of 10

LyC escape fraction lags behind star formation burstiness by ~16 Myr in massive high-redshift galaxies, with longer delays in lower-mass systems.
On Cross-Correlating Line Intensity Maps from SPHEREx during Reionization
astro-ph.GA 2026-06 unverdicted novelty 5.0 of 10

Simulations of SPHEREx line intensity maps show cross-correlations (e.g., Hα × [OIII] at z=5) can reach S/N up to 99, probing galaxies with M < 4×10^10 M⊙, though most signal comes from brighter directly detectable galaxies.

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47 later papers cite it

Evidence: substantial. 43 of the citing papers share no author with it, and 8 of those carry a confident label from Pith's citation classifier.

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1 paper by the same authors is listed below: 1 used its method or tool.

Uses its method or tool 1 of 2 papers with this label · 1 by the same authors

By the same authors

Performed its radiative transfer calculation in a similar fashion to this paper's, taking the radiative transfer grid cell size equal to the gravitational softening length.

Effects of Ultraviolet Background and Local Stellar Radiation on the H_I Column Density Distribution (2010) (same authors) · 0.93 · paraphrased: the licence does not allow quoting

How the literature uses it

8 arXiv papers cite this in 10 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 8 sentences without a confident label

Uses its method or tool 1 paper

We have performed the RT calculation in a similar fashion to the one we did in [ref] , taking the RT grid cell size equal to the gravitational softening length.

Effects of Ultraviolet Background and Local Stellar Radiation on the H_I Column Density Distribution · Effects of Radiative Transfer on $$ · 0.93

Uses its data or values 1 paper

The fiducial values we use for $f_esc,10$ and $α_esc$ are 0.1 and -0.5, respectively [ref] .

Radiative Transfer Simulations of Ly$\alpha$ Intensity Mapping During Cosmic Reionization Including Sources from Galaxies and the Intergalactic Medium · Ly$α$ Photons from Galaxies · 0.92

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