Star Forming Galaxies
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The Properties Of Star Forming Galaxies At Z 2
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Author : Dawn Erb
language : en
Publisher: Universal-Publishers
Release Date : 2005
The Properties Of Star Forming Galaxies At Z 2 written by Dawn Erb and has been published by Universal-Publishers this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Science categories.
We study the properties of star-forming galaxies at redshift z 2, an era in which a substantial fraction of the stellar mass in the universe formed. Using 114 near-IR spectra of the H-alpha and [N II] emission lines and model spectral energy distributions fit to rest-frame UV through IR photometry, we examine the galaxies' star formation properties, dynamical masses and velocity dispersions, spatially resolved kinematics, outflow properties, and metallicities as a function of stellar mass and age. While the stellar masses of the galaxies in our sample vary by a factor of 500, dynamical masses from H-alpha velocity dispersions and indirect estimates of gas masses imply that the variation of stellar mass is due as much to the evolution of the stellar population and the conversion of gas into stars as to intrinsic differences in the total masses of the galaxies. About 10% of the galaxies are apparently young starbursts with high gas fractions, caught just as they have begun to convert large amounts of gas into stars. Using the [N II]/H-alpha ratio of composite spectra to estimate the average oxygen abundance, we find a monotonic increase in metallicity with stellar mass. From the estimated gas fractions, we conclude that the observed mass-metallicity relation is primarily driven by the increase in metallicity as gas is converted to stars. The picture that emerges is of galaxies with a broad range in stellar population properties, from young galaxies with ages of a few tens of Myr, stellar masses M 10 DEGREES9 Msun, and metallicities Z 1/3 Zsun, to massive objects with M* 10 DEGREES11 Msun, Z Zsun, and ages as old as the universe allows. All, however, are rapidly star-forming, power galactic-scale outflows, and have masses in gas and stars of at least 10 DEGREES10 Msun, in keeping with their likely role as the progenitors of elliptical galaxies
Physics Of Star Formation In Galaxies
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Author : F. Palla
language : en
Publisher: Springer Science & Business Media
Release Date : 2006-07-06
Physics Of Star Formation In Galaxies written by F. Palla and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006-07-06 with Science categories.
The book begins with a historical introduction, "Star Formation: The Early History", that presents new material of interest for students and historians of science. This is followed by two long articles on "Pre-Main-Sequence Evolution of Stars and Young Clusters" and "Observations of Young Stellar Objects". These articles on the fascinating problem of star formation from interstellar matter give a thorough overview of present-day theories and observations. The articles contain material so far unpublished in the astronomical literature. The book addresses graduate students and can be used as a textbook for advanced courses in stellar astrophysics.
Star Forming Dwarf Galaxies And Related Objects
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Author : D. Kunth
language : en
Publisher: Atlantica Séguier Frontières
Release Date : 1985
Star Forming Dwarf Galaxies And Related Objects written by D. Kunth and has been published by Atlantica Séguier Frontières this book supported file pdf, txt, epub, kindle and other format this book has been release on 1985 with Dwarf galaxies categories.
Star Formation Galaxies And The Interstellar Medium
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Author : Jose Franco
language : en
Publisher: Cambridge University Press
Release Date : 1993-06-10
Star Formation Galaxies And The Interstellar Medium written by Jose Franco and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 1993-06-10 with Science categories.
The enormously powerful phenomena of starbursts are examined in this book. These spectacular star-forming events are seen on large scales in some galaxies, often triggered by galactic interactions. An intriguing implication of starburst research is that active galactic nuclei (AGN) may not be powered by accreting black holes. Instead theories are presented where compact powerhouses of dust-enshrouded star formation lie at the core of AGN, with supernovae exploding roughly once per year within massive nuclear concentrations of gas. This book collects articles from a timely international conference in Elba, Italy, in 1992; these comprise a thorough review of the most important developments in galactic-scale star formation since the starburst revolution of the late 1980s. This text will introduce graduate students to this exciting area and keep experts apace with rapid developments in it.
Star Formation Rates Of Galaxies
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Author : Andreas Zezas
language : en
Publisher: Cambridge University Press
Release Date : 2021-04-29
Star Formation Rates Of Galaxies written by Andreas Zezas and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-04-29 with Science categories.
Star-formation is one of the key processes that shape the current state and evolution of galaxies. This volume provides a comprehensive presentation of the different methods used to measure the intensity of recent or on-going star-forming activity in galaxies, discussing their advantages and complications in detail. It includes a thorough overview of the theoretical underpinnings of star-formation rate indicators, including topics such as stellar evolution and stellar spectra, the stellar initial mass function, and the physical conditions in the interstellar medium. The authors bring together in one place detailed and comparative discussions of traditional and new star-formation rate indicators, star-formation rate measurements in different spatial scales, and comparisons of star-formation rate indicators probing different stellar populations, along with the corresponding theoretical background. This is a useful reference for students and researchers working in the field of extragalactic astrophysics and studying star-formation in local and higher-redshift galaxies.
A Statistical And Multi Wavelength Study Of Star Formation In Galaxies
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Author : Corentin Schreiber
language : en
Publisher: Springer
Release Date : 2016-09-12
A Statistical And Multi Wavelength Study Of Star Formation In Galaxies written by Corentin Schreiber and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-09-12 with Science categories.
This thesis presents a pioneering method for gleaning the maximum information from the deepest images of the far-infrared universe obtained with the Herschel satellite, reaching galaxies fainter by an order of magnitude than in previous studies. Using these high-quality measurements, the author first demonstrates that the vast majority of galaxy star formation did not take place in merger-driven starbursts over 90% of the history of the universe, which suggests that galaxy growth is instead dominated by a steady infall of matter. The author further demonstrates that massive galaxies suffer a gradual decline in their star formation activity, providing an alternative path for galaxies to stop star formation. One of the key unsolved questions in astrophysics is how galaxies acquired their mass in the course of cosmic time. In the standard theory, the merging of galaxies plays a major role in forming new stars. Then, old galaxies abruptly stop forming stars through an unknown process. Investigating this theory requires an unbiased measure of the star formation intensity of galaxies, which has been unavailable due to the dust obscuration of stellar light.
Galactic And Extragalactic Star Formation
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Author : Ralph E. Pudritz
language : en
Publisher: Springer
Release Date : 1988-05-31
Galactic And Extragalactic Star Formation written by Ralph E. Pudritz and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 1988-05-31 with Science categories.
Proceedings of the NATO Advanced Study Institute, Whistler, B.C., Canada, June 21-July 4, 1987
Star Forming Galaxies Growing Up Over The Last Ten Billion Years
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Author : Amanda Elaine Bauer
language : en
Publisher:
Release Date : 2008
Star Forming Galaxies Growing Up Over The Last Ten Billion Years written by Amanda Elaine Bauer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with Active galaxies categories.
The work presented in this thesis investigates the evolution of starforming galaxies over the last ten billion years. This time period encompasses nearly three-fourths of the age of the Universe, when a substantial fraction of the total stellar mass forms, and the sites of active star formation shift to lower-mass galaxies. The first study presented here combines galaxies from the spectroscopic datasets of the FORS Deep Field and the MUNICS Survey and provides the first significant investigation of the specific star formation rate (SSFR; star formation rate [SFR] per unit stellar mass) over a wide range of stellar masses and redshifts (reaching redshift z = 1:5). From [OII]-derived SFRs, we find that low-mass galaxies have higher SSFRs all the way to z = 1:5, implying that star formation contributes progressively more to the growth of stellar mass in low-mass galaxies than in high-mass galaxies. In the follow-up to this study, we combine several near-infrared-selected samples to create one of the largest collections of galaxies with spectroscopic redshifts and morphologies from Hubble Space Telescope images, to characterize the stellar mass build up in galaxies since z = 1:6. The primary data comes from the FORS Deep Field, the MUNICS Survey, the GOODS-South field as observed by the K20 survey and ESO, and the Sloan Digital Sky Survey as a local comparison sample. After bringing together extensive photometric and spectroscopic data sets from several publicly available surveys, we use identical methods to derive physical properties and investigate how galaxy populations evolve with time. Galaxy properties include stellar masses derived from multiwavelength photometry, star formation rates calculated from [OII][lambda]3726Å emission lines, metallicity, color, and SSFRs. We find that the reddest, yet actively star-forming, disk-dominated galaxy population present at z ~ 1:3, decreases in number by z ~ 0:3 during the same timeframe when the bluest quiescent, disk-dominated galaxy population increases in number. We confirm the previously identified morphological separation in the SSFR versus M[subscript asterisk] plane found for local samples and for galaxies at z = 0:7: bulge-dominated galaxies are more massive and have lower SSFRs. We extend this relation for the first time to z = 1:6, showing that galaxies with high SSFRs and diskdominated structures tend to shift to lower masses as redshift decreases. We identify an observed upper envelop in SSFR that lies roughly parallel to lines of constant SFR, decreases with time, and is unaffected by incompleteness among the samples. We apply common star formation histories (constant, ex ponential, and power law) to understand the evolving populations we see, but cannot simultaneously reproduce low-mass galaxies with high SSFRs and highmass galaxies with low SSFRs at all redshifts and over our full mass range. Current semi-analytic models attempt to understand the mass at which galaxies stop forming stars through connections to Active Galactic Nuclei feedback, gas consumption, declining galaxy merger rates and/or changes in the incoming cold gas supply, but none can explain the gradual and constant decline of star formation consistent among all galaxies below this mass. We suggest a possible resolution where star formation histories of galaxies are dependent on morphology, in addition to the growing evidence for lower mass galaxies to begin forming stars at later times, and with lower initial SFRs than the initial SFRs experienced at earlier times by higher mass galaxies.
From Interstellar Clouds To Star Forming Galaxies Iau S315
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Author : Pascale Jablonka
language : en
Publisher: Cambridge University Press
Release Date : 2016-09-22
From Interstellar Clouds To Star Forming Galaxies Iau S315 written by Pascale Jablonka and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-09-22 with Science categories.
The link between the structure of the interstellar medium in galaxies and the star formation process is a fast-growing area of astrophysical research. The availability of wide-field far-infrared and submillimeter surveys with various space observatories, coupled with the improved capabilities of ground-based millimeter and submillimeter interferometers, has led to spectacular advances in our understanding of star formation modes from solar system scales to galaxy scales. IAU Symposium 315 aims to build a coherent picture of how star formation is fueled on a wide range of scales. Bringing together researchers working on star formation throughout the Universe from nearby clouds to local galaxies to the first star-forming galaxies at high redshift, it makes connections between the latest observations and advanced numerical simulations. It also addresses critical issues, such as the origin and universality of the stellar initial mass function, the nature of star formation 'laws', and the role of feedback.
The Nature Of Dusty Star Forming Galaxies
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Author : William Cowley
language : en
Publisher: Springer
Release Date : 2017-10-02
The Nature Of Dusty Star Forming Galaxies written by William Cowley and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-10-02 with Science categories.
This thesis combines a theoretical model of galaxy formation with a treatment of the radiative transfer in the titular dusty star-forming galaxies. Embedding this within the well-established ΛCDM (Lambda cold dark matter) cosmology, the author was able to simulate galaxy populations from which realistic observational images were synthesised. Based on further analysis, he shows that there is a good correspondence with observations from new instruments such as the SCUBA2 bolometric camera and the Atacama Large Millimeter Array (ALMA) interferometer, and reveals some novel aspects of this exciting galaxy population. In particular, he shows that blending of these galaxies in the imaging produces an artificial enhancement in their clustering, which he dubs “blending bias”. This implies that the host dark matter halo masses for these galaxies have previously been significantly overestimated. He also presents amongst the first predictions from a galaxy formation model for observations of these galaxies that will be made by the James Webb Space Telescope (the successor to the Hubble Space Telescope).