Old Stellar Populations

Old Stellar Populations
Author: Santi Cassisi
Publisher: John Wiley & Sons
Total Pages: 506
Release: 2013-08-29
Genre: Science
ISBN: 3527665544

The book discusses the theoretical path to decoding the information gathered from observations of old stellar systems. It focuses on old stellar systems because these are the fossil record of galaxy formation and provide invaluable information ont he evolution of cosmic structures and the universe as a whole. The aim is to present results obtained in the past few years for theoretical developments in low mass star research and in advances in our knowledge of the evolution of old stellar systems. A particularly representative case is the recent discovery of multiple stellar populations in galactic globular clusters that represents one of the hottest topics in stellar and galactic astrophysics and is discussed in detail. Santi Cassisi has authored about 270 scientific papers, 150 of them in peer-reviewed journals, and the title Evolution of Stars and Stellar Populations.

Stellar Populations

Stellar Populations
Author: Alvio Renzini
Publisher: John Wiley & Sons
Total Pages: 285
Release: 2012-09-19
Genre: Science
ISBN: 3527636625

This up-to-date reference on stellar populations and development models includes coverage of distant galaxies, chemical evolution and supernovae. Written by highly acclaimed authorities in the field, the book makes use of specific problems to reveal the "kitchen secrets."

Outskirts of Galaxies

Outskirts of Galaxies
Author: Johan H. Knapen
Publisher: Springer
Total Pages: 367
Release: 2017-07-09
Genre: Science
ISBN: 3319565702

This book consists of invited reviews written by world-renowned experts on the subject of the outskirts of galaxies, an upcoming field which has been understudied so far. These regions are faint and hard to observe, yet hide a tremendous amount of information on the origin and early evolution of galaxies. They thus allow astronomers to address some of the most topical problems, such as gaseous and satellite accretion, radial migration, and merging. The book is published in conjunction with the celebration of the end of the four-year DAGAL project, an EU-funded initial training network, and with a major international conference on the topic held in March 2016 in Toledo. It thus reflects not only the views of the experts, but also the scientific discussions and progress achieved during the project and the meeting. The reviews in the book describe the most modern observations of the outer regions of our own Galaxy, and of galaxies in the local and high-redshift Universe. They tackle disks, haloes, streams, and accretion as observed through deep imaging and spectroscopy, and guide the reader through the various formation and evolution scenarios for galaxies. The reviews focus on the major open questions in the field, and explore how they can be tackled in the future. This book provides a unique entry point into the field for graduate students and non-specialists, and serves as a reference work for researchers in this exciting new field.

Evolution of Stars and Stellar Populations

Evolution of Stars and Stellar Populations
Author: Maurizio Salaris
Publisher: John Wiley & Sons
Total Pages: 386
Release: 2005-12-13
Genre: Science
ISBN: 9780470092224

Evolution of Stars and Stellar Populations is a comprehensive presentation of the theory of stellar evolution and its application to the study of stellar populations in galaxies. Taking a unique approach to the subject, this self-contained text introduces first the theory of stellar evolution in a clear and accessible manner, with particular emphasis placed on explaining the evolution with time of observable stellar properties, such as luminosities and surface chemical abundances. This is followed by a detailed presentation and discussion of a broad range of related techniques, that are widely applied by researchers in the field to investigate the formation and evolution of galaxies. This book will be invaluable for undergraduates and graduate students in astronomy and astrophysics, and will also be of interest to researchers working in the field of Galactic, extragalactic astronomy and cosmology. comprehensive presentation of stellar evolution theory introduces the concept of stellar population and describes "stellar population synthesis" methods to study ages and star formation histories of star clusters and galaxies presents stellar evolution as a tool for investigating the evolution of galaxies and of the universe in general

3D-Spectroscopy of Dense Stellar Populations

3D-Spectroscopy of Dense Stellar Populations
Author: Tim-Oliver Husser
Publisher: Universitätsverlag Göttingen
Total Pages: 194
Release: 2012
Genre:
ISBN: 3863950925

Globular clusters are gravitationally bound collections of hundreds of thousands of stars that are almost as old as the Universe itself. Although they have been studied for hundreds of years, their formation and evolution is not yet fully understood. We want to fi nd answers to some of the major questions by investing a large amount of observing time with MUSE, the upcoming 2nd generation instrument for ESOś Very Large Telescope. In this thesis I discuss the current state of research on globular clusters as well as the possibilities of this new instrument. Numerical methods for the analysis of MUSE data are presented, including a comprehensive library of synthetic spectra that has been created just for this purpose. The application of these methods to both synthetic and real data is discussed with particular emphasis on a "dry run" that has been conducted for MUSE. Finally, a potential program for the observation of globular clusters is presented.

Stellar Populations of Tidal Tails

Stellar Populations of Tidal Tails
Author: Michael Rodruck
Publisher:
Total Pages:
Release: 2021
Genre:
ISBN:

Galaxy interactions are known to provoke star formation in galactic disks and across tidal tails and other tidally induced features. While previous models have predicted only 10% of the total star formation rate (SFR) to occur in tidal features, recent simulations with explicit stellar feedback have increased this estimate to 20 ~ 50% Observations of the Tadpole galaxy confirm this prediction, as 30% of the system's SFR is occurring in tidal tail star clusters. More specifically, star clusters themselves can host up to 70% of stellar formation in regions of high gas density. If we want to understand the stellar populations that galaxy interactions produce, we must therefore understand their star clusters. However, many clusters are short-lived, subjected to internal (gas expulsion via winds and supernovae) and external (tidal shocks) forces which disrupt them and spill their contents into the tidal debris. Thus, while the majority of star clusters will be destroyed, evidence of their existence is found in the diffuse light. My dissertation studies these stellar populations: bright, compact sources (star clusters), and faint, diffuse light. Old stars from the parent galaxies and young stars formed after the interaction live within the diffuse tidal debris, both contributing to the total luminosity. If we want to look at the stars formed in the interaction, we need a method for disentangling the two. I show how these two populations can be identified in the cumulative tidal tail light, using imaging with the broadband Sloan ugri filters. This technique allows for determination of the total contribution of luminosity and mass from the young and old stellar components. I use the merging system NGC 3256 and its twin tidal tails as a pilot study for this analysis. I find that both tails are dominated in mass by an old population, formed in the host galaxy, with contributions by a young population, formed during the interaction. I also show that the colors of the diffuse light in the Western tidal tail are similar to the colors of its star clusters, suggesting they have a common origin. While ground-based imaging is suitable for deep photometry, star cluster analysis requires high-resolution imaging. I use the Hubble Space Telescope to obtain images in broadband UBVI filters for a sample of 12 tidal tails, in 7 merging systems. I compare these data to stellar evolutionary models to determine ages and masses for star clusters within the tail, finding that many objects show evidence of emission lines, indicating very young ages. Additionally, I use far-ultraviolet (UV) data from GALEX and Swift to obtain star formation rates within the tails. When compared to the total cluster formation rate, I find that the efficiency of cluster formation follows the star formation rate density in these diffuse regions. Finally, I discuss future studies of tidal tails, and how my work on the diffuse light and star clusters will tie together with 21 cm observations of neutral hydrogen (HI) to create a holistic view of the requirements of star formation in tidal tails.

Stellar Populations

Stellar Populations
Author: International Astronomical Union. Symposium
Publisher: Cambridge University Press
Total Pages: 488
Release: 2010
Genre: Galaxies
ISBN: 9780521764841

IAU Symposium 262 presents reviews on the current understanding of the theories of stellar evolution, galaxy formation and galaxy evolution. It emphasises what we have learned in the past few years from massive surveys covering large portions of the sky (e.g. SDSS, HDF, UDF, GOODS, COSMOS). Several critical aspects of research on stellar populations deserve further effort in order to be brought in tune with other areas of astrophysical research. The next ten years will see the opening of major observatories that will increase the quality and quantity of astronomical data by orders of magnitude. The expected benefits from these instruments for the study of stellar populations are explored. This critical review of state of the art observational and theoretical work will appeal to all those working on stellar populations, from distant galaxies to local resolved galaxies and galactic star clusters.