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Related papers: Modelling Starbursts in HII Galaxies: What do we n…

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We present the EUV fluxes derived from the recent "combined stellar structure and atmosphere models" (CoStar models). The atmosphere models in particular account for the stellar wind and include non-LTE effects and line blanketing. We…

Astrophysics · Physics 2007-05-23 D. Schaerer

We utilize medium-resolution JWST/NIRSpec observations of 164 galaxies at $z=2.0-9.3$ from the Cosmic Evolution Early Release Science (CEERS) survey to investigate the evolution of the excitation and ionization properties of galaxies at…

Astrophysics of Galaxies · Physics 2023-01-18 Ryan L. Sanders , Alice E. Shapley , Michael W. Topping , Naveen A. Reddy , Gabriel B. Brammer

We provide an extensive set of theoretical spectral energy distributions of massive stars derived from our "combined stellar structure and atmosphere models". The calculations covering the entire main sequence evolution for initial masses…

Astrophysics · Physics 2016-08-30 Daniel Schaerer , Alex de Koter

We present our recently developed 3-dimensional chemodynamical code for galaxy evolution. This code follows the evolution of different galactic components like stars, dark matter and different components of the interstellar medium (ISM),…

Astrophysics · Physics 2009-11-07 P. Berczik , G. Hensler , Ch. Theis , R. Spurzem

We have analyzed a uniform sample of 16 evolved HII regions located in a 2 deg X 2 deg Galactic field centered at (l,b) = (30 deg, 0 deg) and observed as part of the Herschel Hi-GAL survey. The evolutionary stage of these HII regions was…

We provide here the documentation of the new version of the spectral evolution model PEGASE. PEGASE computes synthetic spectra of galaxies in the UV to near-IR range from 0 to 20 Gyr, for a given stellar IMF and evolutionary scenario (star…

Astrophysics · Physics 2007-05-23 Michel Fioc , Brigitte Rocca-Volmerange

Velocity shifts and differential broadening of radio recombination lines are used to estimate the densities and velocities of the ionized gas in several hypercompact and ultracompact HII regions. These small HII regions are thought to be at…

Astrophysics · Physics 2009-11-13 Eric Keto , Qizhou Zhang , Stanley Kurtz

HII regions play a crucial role in the measurement of the chemical composition of the interstellar medium and provide fundamental data about element abundances that constrain models of galactic chemical evolution. Discrepancies that still…

Solar and Stellar Astrophysics · Physics 2015-11-04 J. A. Weber , A. W. A. Pauldrach , T. L. Hoffmann

The current state-of-the-art of multi-wavelength diagnostic tools (evolutionary synthesis, photoionisation models) for massive star forming regions (HII regions, starbursts, etc.) and some of their input physics (especially model…

Astrophysics · Physics 2007-05-23 Daniel Schaerer

Observations of some starburst-driven galactic superwinds suggest that strong radiative cooling could play a key role in the nature of feedback and the formation of stars and molecular gas in star-forming galaxies. These catastrophically…

Astrophysics of Galaxies · Physics 2022-09-30 A. Danehkar , M. S. Oey , W. J. Gray

The determination of chemical composition is crucial for investigating the formation and evolution of star forming galaxies and provides a powerful tool to constrain the effects of galactic winds and accretion from the cosmic web. In this…

Astrophysics of Galaxies · Physics 2018-10-03 Rolf Kudritzki , Miguel A. Urbaneja

We present a new generation of chemically consistent evolutionary synthesis models for galaxies of various spectral types from E through Sd. The models follow the chemical enrichment of the ISM and take into account the increasing initial…

The variations of the metallicity and ionization parameter in HII regions are usually thought to be the dominant factors that produce the variations we see in the observed emission line spectra. There is an increasing amount of evidence…

Astrophysics of Galaxies · Physics 2022-03-16 Xihan Ji , Renbin Yan

The morphology of HII regions around young star clusters provides insight into the timescales and physical processes that clear a cluster's natal gas. We study ~700 young clusters (<10Myr) in three nearby spiral galaxies (NGC 7793, NGC…

We compare the cosmic evolution of star formation rates in galaxies with that of their neutral hydrogen densities. We highlight the need for neutral hydrogen to be continually replenished from a reservoir of ionized gas to maintain the…

Astrophysics · Physics 2009-11-13 A. M. Hopkins , N. M. McClure-Griffiths , B. M. Gaensler

Accurate synthetic models of stellar populations are constructed and used in evolutionary models of stellar populations in forming galaxies. Following their formation, the late type galaxies are assumed to follow the Schmidt law for star…

Astrophysics · Physics 2009-10-30 R. Jimenez , A. Kashlinsky

In this paper, we use different luminosity ratios to trace the histories of star formation of two different kinds of starburst galaxies: HII galaxies and starburst nucleus galaxies (SBNGs). The mean star formation rates (SFRs) for these…

Astrophysics · Physics 2007-05-23 Roger Coziol

In Smoothed Particles Hydrodynamics (SPH) codes with a large number of particles, star formation as well as gas and metal restitution from dying stars can be treated statistically. This approach allows to include detailed chemical evolution…

Astrophysics · Physics 2011-07-18 C. Lia , L. Portinari , G. Carraro

We re-investigated the use of the Hubble diagram to measure the cosmological constant ($\Lambda$) and the mass density of the Universe ($\Omega_M$). We find an important focusing effect in $\Lambda$ for redshifts about 3. This effect…

Astrophysics · Physics 2009-10-31 Jorge Melnick , Roberto Terlevich , Elena Terlevich

Most stars in the Galaxy are believed to be formed within star clusters from collapsing molecular clouds. However, the complete process of star formation, from the parent cloud to a gas-free star cluster, is still poorly understood. We…

Astrophysics of Galaxies · Physics 2017-10-23 Elena Gavagnin , Andreas Bleuler , Joakim Rosdahl , Romain Teyssier