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Related papers: Escape of Ionizing Radiation from High Redshift Ga…

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Flux estimates for ionizing radiation escaping from star-forming galaxies with characteristic UV luminosities ($L^{*}_{1500(1+z)}$) derived from GALEX and the VIMOS-VLT Deep Survey, are presented as a function of redshift and assumed escape…

Astrophysics of Galaxies · Physics 2017-09-06 Stephan R. McCandliss , John M. O'Meara

We calculate the hydrogen and helium-ionizing radiation escaping star-forming molecular clouds, as a function of the star cluster mass and compactness, using a set of high-resolution radiation-magneto-hydrodynamic simulations of star…

Astrophysics of Galaxies · Physics 2020-01-29 Chong-Chong He , Massimo Ricotti , Sam Geen

The escape of ultraviolet photons from the densest regions of the interstellar medium (ISM) --- Giant Molecular Clouds (GMCs) --- is a poorly constrained parameter which is vital to understanding the ionization of the ISM and the…

Astrophysics of Galaxies · Physics 2018-02-21 Corey S. Howard , Ralph E. Pudritz , Bill E. Harris , Ralf S. Klessen

In this work we investigate the dependence of the escape fraction of ionizing photons, $f_{\rm esc}$, on various galaxy and host halo properties during the epoch of reionization. We post-process the TNG50 magneto-hydrodynamical simulation…

Astrophysics of Galaxies · Physics 2023-03-29 Ivan Kostyuk , Dylan Nelson , Benedetta Ciardi , Martin Glatzle , Annalisa Pillepich

Recent observations have successfully detected UV or infrared flux from galaxies at the epoch of reionization. However, the origin of their radiative properties has not been fully understood yet. Combining cosmological hydrodynamic…

Astrophysics of Galaxies · Physics 2020-06-10 Shohei Arata , Hidenobu Yajima , Kentaro Nagamine , Yuexing Li , Sadegh Khochfar

Ionizing photons must have escaped from high-redshift galaxies, but the neutral high-redshift intergalactic medium makes it unlikely to directly detect these photons during the Epoch of Reionization. Indirect methods of studying ionizing…

Astrophysics of Galaxies · Physics 2022-08-17 Thomas Seive , John Chisholm , Floriane Leclercq , Gregory Zeimann

Star forming galaxies have long been considered the dominant sources of the cosmic ultraviolet background radiation at early epochs. However, observing and characterizing the galaxy population with significant ionizing emission has proven…

Astrophysics of Galaxies · Physics 2017-04-12 J. Japelj , E. Vanzella , F. Fontanot , S. Cristiani , G. B. Caminha , P. Tozzi , I. Balestra , P. Rosati , M. Meneghetti

The Epoch of Reionization marks the last major phase transition in the early Universe, during which the majority of neutral hydrogen once filling the intergalactic medium was ionized by the first galaxies. The James Webb Space Telescope is…

Astrophysics of Galaxies · Physics 2025-07-01 Cody Carr , Renyue Cen , Sophia Flury , Sally Oey , Stephan McCandliss , Allison Strom

We couple the DELPHI framework for galaxy formation with a model for the escape of ionizing photons to study both its variability with galaxy assembly and the resulting key reionization sources. In this model, leakage either occurs through…

Astrophysics of Galaxies · Physics 2023-06-28 Jonas Bremer , Pratika Dayal

In order to assess the contribution of Lyman break galaxies (LBGs) and Lyman alpha emitters (LAEs) at redshifts 3<z<7 to the ionization of intergalactic medium (IGM), we investigate the escape fractions of ionizing photons from…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Hidenobu Yajima , Masayuki Umemura , Masao Mori , Taishi Nakamoto

The escape fraction, fesc, of ionizing photons from early galaxies is a crucial parameter for determining whether the observed galaxies at z > 6 are able to reionize the high-redshift intergalactic medium. Previous attempts to measure fesc…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-28 Elizabeth R. Fernandez , J. Michael Shull

A population of early star-forming galaxies is the leading candidate for the re-ionization of the universe. It is still unclear what conditions and physical processes would enable a significant fraction of the ionizing photons to escape…

Astrophysics of Galaxies · Physics 2015-09-16 Rachael Alexandroff , Timothy Heckman , Sanchayeeta Borthakur , Roderik Overzier , Claus Leitherer

A fundamental requirement for reionizing the Universe is that a sufficient fraction of the ionizing photons emitted by galaxies successfully escapes into the intergalactic medium. However, due to the scarcity of high-redshift observational…

We have studied the effects of gas density inhomogeneities on the escape of ionising Lyman continuum (Lyc) photons from Milky Way-type galaxies via 3D numerical simulations using the Monte Carlo radiative transfer code CRASH (Ciardi et al.…

Astrophysics · Physics 2009-11-07 B. Ciardi , S. Bianchi , A. Ferrara

We compute the ionizing radiation field at low redshift, arising from Seyferts, QSOs, and starburst galaxies. This calculation combines recent Seyfert luminosity functions, extrapolated ultraviolet fluxes from our IUE-AGN database, and a…

Astrophysics · Physics 2009-10-31 J. M. Shull , D. Roberts , M. L. Giroux , S. V. Penton , M. A. Fardal

We measure escape fractions, $f_{\rm esc}$, of ionizing radiation from galaxies in the SPHINX suite of cosmological radiation-hydrodynamical simulations of reionization, resolving halos with $M_{\rm vir} \gtrapprox 7.5 \times 10^7 \…

Measurements of the ionisation state of the intergalactic medium (IGM) can probe the sources of the extragalactic ionising background. We provide new measurements of the ionising emissivity of galaxies using measurements of the ionising…

Astrophysics of Galaxies · Physics 2025-07-04 Christopher Cain , Anson D'Aloisio , Julian B. Munoz

Reionization is thought to have occurred in the redshift range of $6 < z < 9$, which is now being probed by both deep galaxy surveys and CMB observations. Using halo abundance matching over the redshift range $5<z<8$ and assuming smooth,…

Astrophysics of Galaxies · Physics 2016-05-04 Guochao Sun , Steven R. Furlanetto

To date no direct detection of Lyman continuum emission has been measured for intermediate--redshift z~1 star-forming galaxies . We combine HST grism spectroscopy with GALEX UV and ground--based optical imaging to extend the search for…

We use the first data release from the SINGG H-alpha survey of HI-selected galaxies to study the quantitative behavior of the diffuse, warm ionized medium (WIM) across the range of properties represented by these 109 galaxies. The mean…