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Related papers: Narrow escape: how ionizing photons escape from di…

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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 of Lyman continuum photons (fesc(LyC)) is the last key unknown in our understanding of cosmic reionization. Directly estimating the escape fraction (fesc) of ionizing photons in the epoch of reionization (EoR) is…

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

Several observational and theoretical arguments suggest that starburst galaxies may rival quasars as sources of metagalactic ionizing radiation at redshifts z > 3. Reionization of the intergalactic medium (IGM) at z > 5 may arise, in part,…

Astrophysics · Physics 2009-10-31 Massimo Ricotti , J. Michael Shull

The escape of ionizing radiation from galaxies plays a critical role in the evolution of gas in galaxies, and the heating and ionization history of the intergalactic medium. We present semi-analytic calculations of the escape fraction of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Andrew Benson , Aparna Venkatesan , J. Michael Shull

The fraction of ionizing photons that escape their host galaxies to ionize hydrogen in the inter-galactic medium (IGM) is a critical parameter in analyses of the reionization era. In this paper we use the Meraxes semi-analytic galaxy…

Astrophysics of Galaxies · Physics 2023-12-11 Simon J. Mutch , Bradley Greig , Yuxiang Qin , Gregory B. Poole , J. Stuart B. Wyithe

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

Using broadband photometry from the Hubble Space Telescope in combination with Very Large Telescope narrowband Halpha observations of the nearby spiral galaxy NGC 300, we explore a method for estimating the escape fractions of…

Solar and Stellar Astrophysics · Physics 2016-08-03 Florian Niederhofer , Michael Hilker , Nate Bastian , Barbara Ercolano

We explore scenarios for reionizing the intergalactic medium with low galaxy ionizing photon escape fractions. We combine simulation-based halo-mass dependent escape fractions with an extrapolation of the observed galaxy rest-ultraviolet…

The fraction of ionizing photons that escape high-redshift galaxies sensitively determines whether galaxies reionized the early universe. However, this escape fraction cannot be measured from high-redshift galaxies because the opacity of…

Astrophysics of Galaxies · Physics 2018-08-08 J. Chisholm , S. Gazagnes , D. Schaerer , A. Verhamme , J. R. Rigby , M. Bayliss , K. Sharon , M. Gladders , H. Dahle

Proto-galaxies forming in low-mass dark matter haloes are thought to provide the majority of ionizing photons needed to reionize the Universe, due to their high escape fractions of ionizing photons. We study how the escape fraction in…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-09 Jan-Pieter Paardekooper , Sadegh Khochfar , Claudio Dalla Vecchia

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

Far-ultraviolet spectra obtained with $FUSE$ show that the strong $CII\lambda$1036 interstellar absorption-line is essentially black in five of the UV-brightest local starburst galaxies. Since the opacity of the neutral ISM below the…

Astrophysics · Physics 2009-11-06 T. Heckman , K. R. Sembach , G. Meurer , C. Leitherer , D. Calzetti , C. L. Martin

The intrinsic escape fraction of ionizing Lyman continuum photons ($f_{esc}$) is crucial to understand whether galaxies are capable of reionizing the neutral hydrogen in the early universe at z>6. Unfortunately, it is not possible to access…

Astrophysics of Galaxies · Physics 2016-11-15 Andreas L. Faisst

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 use a large sample of galaxies at z~3 to establish a relationship between reddening, neutral gas covering fraction (fcov(HI)), and the escape of ionizing photons at high redshift. Our sample includes 933 galaxies at z~3, 121 of which…

Astrophysics of Galaxies · Physics 2016-09-21 Naveen A. Reddy , Charles C. Steidel , Max Pettini , Milan Bogosavljevic , Alice Shapley

We study the ionization structure of galactic outflows in 37 nearby, star forming galaxies with the Cosmic Origins Spectrograph on the Hubble Space Telescope. We use the O I, Si II, Si III, and Si IV ultraviolet absorption lines to…

Astrophysics of Galaxies · Physics 2016-03-09 John Chisholm , Christy A. Tremonti , Claus Leitherer , Yanmei Chen , Aida Wofford

The part played by stars in the ionization of the intergalactic medium remains an open question. A key issue is the proportion of the stellar ionizing radiation that escapes the galaxies in which it is produced. Spectroscopy of gamma-ray…

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

There are few observational constraints on how the escape of ionizing photons from starburst galaxies depends on galactic parameters. Here, we report on the first major detection of an ionization cone in NGC 5253, a nearby starburst galaxy.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Jordan Zastrow , M. S. Oey , Sylvain Veilleux , Michael McDonald , Crystal L. Martin