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Related papers: Predicted UV properties of very metal-poor starbur…

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We examine spectral properties of the ionising continua, the Lyman-break, and the Ly-a and HeII 1640 recombination lines in starbursts. The transition from primordial galaxies to currently observed metallicities, is examined. For the…

Astrophysics · Physics 2009-07-09 Daniel Schaerer

We have used extensive libraries of model and empirical galaxy spectra (assembled respectively from the population synthesis code of Bruzual and Charlot and the fourth data release of the Sloan Digital Sky Survey) to interpret some puzzling…

Astrophysics · Physics 2009-10-08 Jarle Brinchmann , Max Pettini , Stephane Charlot

Nearby dwarf galaxies provide a unique laboratory in which to test stellar population models below $Z_\odot/2$. Such tests are particularly important for interpreting the surprising high-ionization UV line emission detected at $z>6$ in…

Deep optical spectroscopic surveys of galaxies provide us a unique opportunity to investigate rest-frame ultra-violet (UV) emission line properties of galaxies at ${z \sim 2-4.5}$. Here we combine VLT/MUSE Guaranteed Time Observations of…

We revisit calculations of nebular hydrogen Lya and HeII 1640A line strengths for population III galaxies, undergoing continuous and bursts of star formation. We focus on initial mass functions (IMFs) motivated by recent theoretical…

Astrophysics of Galaxies · Physics 2016-12-14 Lluís Mas-Ribas , Mark Dijkstra , Jaime E. Forero-Romero

We present synthetic ultraviolet spectra of metal-poor star-forming galaxies which were calculated with the Starburst99 package. A new spectral library was generated from HST observations of O stars in the Large and Small Magellanic Clouds.…

Astrophysics · Physics 2009-10-31 Claus Leitherer , Joao Leao , Tim Heckman , Daniel Lennon , Max Pettini , Carmelle Robert

Resolution of nearby giant HII regions into their stellar and nebular constituents provides fundamental insights for interpreting more distant and powerful starburst activity. The following summarizes recent advances in our understanding of…

Astrophysics · Physics 2007-05-23 William H. Waller

The chemical composition of high redshift galaxies is an important property which gives clues to their past history and future evolution and yet is difficult to measure with current techniques. In this paper we investigate new metallicity…

We review the expected properties of Pop III and very metal-poor starburst and the behaviour the Lyman-alpha and HeII 1640 emission lines, which are most likely the best/easiest signatures to single out such objects. Existing claims of Pop…

Astrophysics · Physics 2009-11-13 Daniel Schaerer

There is a long history of using optical emission and absorption lines to constrain the metallicity and ionization parameters of gas in galaxies. However, comparable diagnostics are less well-developed for the UV. Here, we assess the…

Astrophysics of Galaxies · Physics 2018-08-09 Nell Byler , Julianne Dalcanton , Charlie Conroy , Benjamin Johnson , Emily Levesque , Danielle Berg , .

In preparation of a study of the HeII/HI ratio towards the bright QSO HS1700+6416, we predict the metal line content of the far-UV spectral range by modelling 18 metal absorption line systems with redshifts 0.2<z<2.6 identified in the…

Astrophysics · Physics 2009-11-11 C. Fechner , D. Reimers , A. Songaila , R. A. Simcoe , M. Rauch , W. L. W. Sargent

We have observed a sample of 14 nearby ($z \sim 0.03$) star-forming blue compact galaxies in the rest-frame far-UV ($\sim1150-2200 \AA$) using the Cosmic Origins Spectrograph on the Hubble Space Telescope. We have also generated a grid of…

Astrophysics of Galaxies · Physics 2015-06-03 Erika Zetterlund , Emily M. Levesque , Claus Leitherer , Charles W. Danforth

We compute synthetic optical and ultraviolet (UV) emission-line properties of galaxies in a full cosmological framework by coupling, in post-processing, new-generation nebular-emission models with high-resolution, cosmological zoom-in…

Astrophysics of Galaxies · Physics 2019-05-29 Michaela Hirschmann , Stéphane Charlot , Anna Feltre , Thorsten Naab , Rachel S. Somerville , Ena Choi

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)…

We study the spectroscopic appearance of very massive stars and their effect on the integrated light of starbursts at low metallicity (Z). We adopt two frameworks for the mass loss rates of VMS: in one case we assume no Z dependence, in the…

Solar and Stellar Astrophysics · Physics 2025-06-25 F. Martins , A. Palacios , D. Schaerer , R. Marques-Chaves

We obtained medium-resolution ultraviolet (UV) spectra between 1150 and 1450 Angstroms of the four UV-bright, infrared (IR)-luminous starburst galaxies IRAS F08339+6517, NGC 3256, NGC 6090, and NGC 7552 using the Cosmic Origins Spectrograph…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Claus Leitherer , Rupali Chandar , Christy Tremonti , Aida Wofford , Daniel Schaerer

Motivated by recent observations of galaxies dominated by emission lines, which show evidence of being metal poor with young stellar populations, we present calculations of multiple model grids with a range of abundances, ionization…

We discuss the expected spectral properties of starbursts of zero and very low metallicity covering their restframe EUV and UV to optical spectra. The main criteria to establish such a "primeval" nature are summarised. Finally we compare…

Astrophysics · Physics 2007-05-23 Daniel Schaerer

[Abbreviated] Rest-frame UV emission lines probe physical parameters of the emitting star-forming galaxies and their environments. The strongest main UV line, Ly$\alpha$, has been instrumental in advancing the general knowledge of galaxy…

We explore the origin of the observed Lya and other UV lines from galaxies at z<3.7 by detailed modelling of the spectra. The objects are chosen among those showing a) UV-optical-near-IR lines, b) only UV lines and c) those showing Lya in…

Astrophysics of Galaxies · Physics 2015-04-28 M. Contini
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