English
Related papers

Related papers: How old are the HII Galaxies?

200 papers

We have collected a large body of NIR (H band), UV (2000 A) and Halpha measurements of late-type galaxies. These are used, jointly with spectral evolutionary synthesis models, to study the initial mass function (IMF) in the mass range m > 2…

Astrophysics · Physics 2010-11-09 Alessandro Boselli , Giuseppe Gavazzi , Jose Donas , Marco Scodeggio

One of the fundamental factors regulating the evolution of galaxies is stellar feedback. However, we still do not have strong observational constraints on the relative importance of the different feedback mechanisms (e.g. radiation, ionised…

(Abridged) We investigate optical and near-IR color gradients in a sample of 172 low-inclination galaxies spanning Hubble types S0--Irr. The colors are compared to stellar population synthesis models from which luminosity-weighted average…

Astrophysics · Physics 2009-11-10 Lauren A. MacArthur , Stephane Courteau , Eric Bell , Jon Holtzman

We present a new method to determine the star formation and metal enrichment histories of any resolved stellar system. This method is based on the fact that any observed star in a colour-magnitude diagram will have a certain probability of…

Astrophysics of Galaxies · Physics 2015-06-11 Emma E. Small , David Bersier , Maurizio Salaris

Understanding what shapes the cold gas component of galaxies, which both provides the fuel for star formation and is strongly affected by the subsequent stellar feedback, is a crucial step towards a better understanding of galaxy evolution.…

We introduce a framework for simultaneously investigating the structure and luminosity evolution of early-type gravitational lens galaxies. The method is based on the fundamental plane, which we interpret using the aperture mass-radius…

Astrophysics · Physics 2009-11-10 D. Rusin , C. S. Kochanek

Optical and infrared emission lines from HII regions are an important diagnostic used to study galaxies, but interpretation of these lines requires significant modeling of both the internal structure and dynamical evolution of the emitting…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Silvia Verdolini , Sherry C. C. Yeh , Mark R. Krumholz , Christopher D. Matzner , Alexander G. G. M. Tielens

The star formation histories (SFHs) of dwarf galaxies are thought to be \emph{bursty}, with large -- order of magnitude -- changes in the star formation rate on timescales similar to O-star lifetimes. As a result, the standard…

Ultracompact and hypercompact HII regions appear when a star with a mass larger than about 15 solar masses starts to ionize its own environment. Recent observations of time variability in these objects are one of the pieces of evidence that…

Astrophysics of Galaxies · Physics 2015-05-28 Roberto Galván-Madrid , Thomas Peters , Eric Keto , Mordecai-Mark Mac Low , Robi Banerjee , Ralf S. Klessen

This study of 117 low-redshift Im and Sm galaxies investigates the star formation rates of late-type galaxies, to determine whether they are quasi-continuous or dominated by bursts with quiescent interludes. We analyse the distribution of…

Astrophysics · Physics 2009-11-13 P. A. James , M. Prescott , I. K. Baldry

Massive stars influence the surrounding universe far out of proportion to their numbers through ionizing radiation, supernova explosions, and heavy element production. Their formation requires the collapse of massive interstellar gas clouds…

Astrophysics of Galaxies · Physics 2015-05-19 Ralf S. Klessen , Thomas Peters , Robi Banerjee , Mordecai-Mark Mac Low , Roberto Galvan-Madrid , Eric R. Keto

One of the fundamental goals of modern astrophysics is to estimate the physical parameters of galaxies. We present a hierarchical Bayesian model to compute age maps from images in the \Ha\ line (taken with Taurus Tunable Filter, TTF),…

We present results from a photometric H-alpha survey of 22 nuclear rings, aiming to provide insight into their star formation properties, including age distribution, dynamical timescales, star formation rates, and galactic bar influence. We…

Astrophysics · Physics 2009-11-13 Lisa M. Mazzuca , Johan H. Knapen , Sylvain Veilleux , Michael W. Regan

We compile and carrefully homogenize local galaxy samples with available information on stellar, $\rm HI$ and/or $\rm H_{2}$ masses, and morphology. After processing the information on upper limits in the case of non gas detections, we…

The study of the ages of early-type galaxies and their dependence on galaxy mass and environment is crucial for understanding the formation and early evolution of galaxies. We review recent works on the M/L ratio evolution, as derived from…

Astrophysics · Physics 2007-05-23 Sperello di Serego Alighieri , Alessandro Bressan , Lucia Pozzetti

The relationship between star formation and infrared emission in galaxies will be investigated. If galaxies were simple objects and young stars were completely covered with dust, then all the absorbed light of the young stars would be…

Astrophysics · Physics 2023-03-08 Nikolaos D. Kylafis , Angelos Misiriotis

Understanding the diversity of star formation histories (SFHs) of galaxies is key to reconstructing their evolutionary paths. Traditional models often assume parametric forms such as delayed-tau or exponentially declining models, which may…

Astrophysics of Galaxies · Physics 2025-10-31 Robin Eappen , Pavel Kroupa

Unless the nearby universe is subtly anomalous, it should contain a relatively normal selection of galaxies whose histories are representative of field galaxies in general throughout the Universe. We can therefore take advantage of our…

Astrophysics · Physics 2007-05-23 Eline Tolstoy