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Related papers: High-Redshift Galaxies with Large Ionization Param…

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We explore the production and escape of ionizing photons in young galaxies by investigating the ultraviolet and optical emission-line properties of models of ionization-bounded and density-bounded HII regions, active-galactic-nucleus (AGN)…

The detection of Lyman-$\alpha$ emitting galaxies (LAEs) puts severe constraints on the reionization history. In this Paper we derive the properties of very high-$z$ LAEs predicted in the only two reionization scenarios shown in a previous…

We use deep spectroscopy from the Hubble Space Telescope (HST) Wide-Field-Camera 3 (WFC3) IR grisms combined with broad-band photometry to study the stellar populations, gas ionization and chemical abundances in star-forming galaxies at…

We present a new model to compute the luminosity of emission lines in star forming galaxies and apply this in the semi-analytical galaxy formation code GALFORM. The model combines a pre-computed grid of HII region models with an empirical…

Astrophysics of Galaxies · Physics 2022-01-11 C. M. Baugh , C. G. Lacey , V. Gonzalez-Perez , G. Manzoni

We present a study of the ionized gas in a sample of 65 nearby early-type galaxies, for which we have acquired optical intermediate-resolution spectra. Emission lines are detected in ~89 % of the sample. The incidence of emission appears…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-23 F. Annibali , A. Bressan , R. Rampazzo , W. W. Zeilinger

Understanding Ly$\alpha$ emitting galaxies (LAEs) can be a key to reveal cosmic reionization and galaxy formation in the early Universe. Based on halo merger trees and Ly$\alpha$ radiation transfer calculations, we model redshift evolution…

Astrophysics of Galaxies · Physics 2018-05-02 Hidenobu Yajima , Kazuyuki Sugimura , Kenji Hasegawa

We present constraints on the massive star and ionized gas properties for a sample of 62 star-forming galaxies at $z\sim2.3$. Using BPASS stellar population models, we fit the rest-UV spectra of galaxies in our sample to estimate age and…

Gas metallicity, ionization parameter, and gas pressure can affect the observed ratios of specific strong emission lines within galaxies. While the theoretical strong lines diagnostics for gas metallicity, ionization parameters, and gas…

Astrophysics of Galaxies · Physics 2024-11-07 Peixin Zhu , Lisa J. Kewley , Ralph Sutherland

Searches for Lyman-alpha emission lines are among the most effective ways to identify high-redshift galaxies. They are particularly interesting because they probe not only the galaxies themselves but also the ionization state of the…

Astrophysics · Physics 2009-11-13 Steven R. Furlanetto , Matias Zaldarriaga , Lars Hernquist

Stellar population models produce radiation fields that ionize oxygen up to O+2, defining the limit of standard HII region models (<54.9 eV). Yet, some extreme emission line galaxies, or EELGs, have surprisingly strong emission originating…

Astrophysics of Galaxies · Physics 2021-12-08 Danielle A. Berg , John Chisholm , Dawn K. Erb , Evan D. Skillman , Richard W. Pogge , Grace M. Olivier

We present $[OIII]/H_{\rm \beta}$ emision line flux ratio predictions for galaxies at $z \sim 7-9$ using the MAPPINGS V v5.2.0 photoionization modelling code combined with an analytic galaxy formation model. Properties such as pressure and…

Astrophysics of Galaxies · Physics 2025-04-08 Aadarsh Pathak , J. Stuart B. Wyithe , Ralph S. Sutherland , L. J Kewley

The fraction of ionizing photons that escape from young star-forming galaxies is one of the largest uncertainties in determining the role of galaxies in cosmic reionization. Yet traditional techniques for measuring this fraction are…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Tucker Jones , Richard S. Ellis , Matthew A. Schenker , Daniel P. Stark

In this series of lectures, I review our observational understanding of high-$z$ Ly$\alpha$ emitters (LAEs) and relevant scientific topics. Since the discovery of LAEs in the late 1990s, more than ten (one) thousand(s) of LAEs have been…

Astrophysics of Galaxies · Physics 2020-12-23 Masami Ouchi

The Ly$\alpha$ emission line is a characteristic feature found in high-$z$ galaxies, serving as a probe of cosmic reionization. While previous works present various correlations between Ly$\alpha$ emission and physical properties of host…

The possibility that star-forming galaxies may leak ionizing photons is at the heart of many present-day studies that investigate the reionization of the Universe. We test this hypothesis on local blue compact dwarf galaxies of very high…

Astrophysics of Galaxies · Physics 2015-06-24 G. Stasinska , Yu. Izotov , C. Morisset , N. Guseva

We present a new model for high redshift Lyman-Alpha Emitters (LAEs) in the cosmological context which takes into account the resonant scattering of Ly-a photons through expanding gas. The GALICS semi-analytic model provides us with the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Thibault Garel , Jérémy Blaizot , Bruno Guiderdoni , Daniel Schaerer , Anne Verhamme , Matthew Hayes

Spectroscopic observations of massive $z>7$ galaxies selected to have extremely large [OIII]+H$\beta$ equivalent width (EW $\sim1500$ \r{A}) have recently revealed large Ly$\alpha$ detection rates, in contrast to the weak emission seen in…

Astrophysics of Galaxies · Physics 2021-03-17 Mengtao Tang , Daniel Stark , Jacopo Chevallard , Stephane Charlot , Ryan Endsley , Enrico Congiu

Strong high-ionization lines such as HeII of young galaxies are puzzling at high and low redshift. Although recent studies suggest the existence of non-thermal sources, whether their ionizing spectra can consistently explain multiple major…

We present results from a survey of galaxies in the fields of six z>3 Damped Lyman alpha systems (DLAs) using the Multi Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope (VLT). We report a high detection rate of up to ~80% of…

Charting the Epoch of Reionization demands robust assessments of what drives the production of ionizing photons in high-redshift star-forming galaxies (SFGs), and requires better predictive capabilities from current observations. Using a…

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