The Spectral Energy Distributions Of Gas Rich Galaxies
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The Spectral Energy Distributions Of Gas Rich Galaxies
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Author : Cristina C. Popescu
language : en
Publisher: American Institute of Physics
Release Date : 2005-04-28
The Spectral Energy Distributions Of Gas Rich Galaxies written by Cristina C. Popescu and has been published by American Institute of Physics this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005-04-28 with Science categories.
Heidelberg, Germany, 4-8 October 2004
Gas Rich Galaxies In The Alfalfa Survey
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Author : Shan Huang
language : en
Publisher:
Release Date : 2013
Gas Rich Galaxies In The Alfalfa Survey written by Shan Huang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
Making use of galaxy catalog generated by the ALFALFA survey ([alpha].40) and photometry from the Sloan Digital Sky Survey (SDSS) and GALEX, etc., we investigate the gas, stellar, and star formation (SF) properties of HI-selected galaxies in the local universe. In addition to the HI 21 cm line measurements, stellar masses (M*) and star formation rates (SFRs) are derived from fitting the UVoptical spectral energy distributions. We examine 229 low HI mass dwarf galaxies, including a complete sample of 176 galaxies with HI masses
Far Uv To Mid Ir Spectral Energy Distributions Of Nearby Merging Galaxies
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Author : Madalyn Elizabeth Weston
language : en
Publisher:
Release Date : 2022
Far Uv To Mid Ir Spectral Energy Distributions Of Nearby Merging Galaxies written by Madalyn Elizabeth Weston and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with Electronic dissertations categories.
Simulations of gas-rich, major galaxy mergers predict elevated amounts of star formation (SF) and nuclear black hole growth (active galactic nuclei, or AGN). This model is supported by observations that find enhanced SF in mergers, but support for the AGN-merger connection remains uncertain. Interstellar dust, a bi-product of SF, can block much of the light from an AGN and re-radiate that energy at infrared (IR) wavelengths. Therefore, quantifying the amount of buried AGN activity in the IR is key to understanding the role of major mergers in galaxy evolution. Spectral energy distributions (SEDs) allow Astrophysicists to disentangle AGN activity from SF. I hypothesize that applying SED analysis to a sample of merging galaxies will show an enhancement in AGN activity over control galaxies. I perform SED analysis from the far-ultraviolet (FUV) to the mid-IR on a sample of 49 merging galaxies and 49 statistically-matched control galaxies in the nearby universe. I find that the SED AGN luminosity correlates with the [OIII] luminosity, a common indicator of AGN power. I find that galaxies previously identified as Seyfert or WISE AGNs generally have a higher SED AGN luminosity. I do not find an increased occurrence of SED-detected AGNs in merging over control galaxies, rejecting our study hypothesis. To meet the interdisciplinary requirements of this degree, I also design a new graduate-level course in Multicultural Education for STEM (science, technology, engineering and mathematics) fields. “Diversity and Inclusion” have become buzz words in STEM, as research continues to show achievement and participation gaps for women, people of color, disabled persons, those of low socio-economic status, and members of the LGBTQIA+ community. Research about the STEM gaps has existed for decades, particularly with respect to teaching practices that contribute to under-representation. Yet little change has occurred in STEM classrooms. Graduate students (i.e., future STEM professors and industry leaders) stand in a unique position to impact diversity and inclusion efforts. Through targeted education centered on diversity and inclusion in teaching methods, we can produce a new generation of STEM educators who are aware and mindful of their unique role in fighting inequality in STEM.
Spectral Constraints On Models Of Gas In Clusters Of Galaxies
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Author : Mark J. Henriksen
language : en
Publisher:
Release Date : 1985
Spectral Constraints On Models Of Gas In Clusters Of Galaxies written by Mark J. Henriksen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1985 with Galaxies categories.
Exploring The Interplay Between Star Formation And Active Galactic Nuclei And The Role Of Environment In Galaxy Evolution
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Author : Jonathan Florez
language : en
Publisher:
Release Date : 2021
Exploring The Interplay Between Star Formation And Active Galactic Nuclei And The Role Of Environment In Galaxy Evolution written by Jonathan Florez and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
One of the central goals of extragalactic astronomy is to understand how galaxies grow their stellar mass and central black holes, the connection between star formation and active galactic nuclei (AGN), and the impact of environment on this growth. In this thesis, I utilize multiwavelength surveys that are both deep and wide, advanced computational codes that model the spectral energy distributions of galaxies with and without AGN, as well as state-of-the-art simulations of galaxy evolution in order to explore how galaxy properties are impacted by their surrounding environment and AGN activity. These studies explore galaxies over a redshift range of 0.015 z 0.023 (lookback time of ~ 0.2 to ~ 0.3 Gyr), and over a redshift range of 0.5 z 3.0 (lookback time of ~ 5 to ~ 12 Gyr). The large-area surveys used here provide some of the largest and most statistically robust samples to-date of rare massive galaxies (with stellar mass M [subscript *] 1011 M☉) and extremely luminous AGN (with X-ray luminosity L [subscript X] 1044 erg s−1) out to z ~ 3, thereby limiting the effects of cosmic variance and Poisson statistics. I analyze the observed stellar masses and star formation rates of galaxies as a function of environment and AGN activity, compare the empirical results to theoretical models of galaxy evolution, and discuss the implications of such comparisons. This work will provide significant guidance and constraints to the future development of theoretical models of galaxy growth. In Chapter 2 (Florez et al. 2021, ApJ, 906, 97) I measure the environmental dependence, where environment is defined by the distance to the third nearest neighbor, of multiple galaxy properties inside the Environmental COntext (ECO) catalog. I focus primarily on void galaxies at redshifts z = 0.015 - 0.023, which I define as the 10% of galaxies having the lowest local density. I compare the properties of void and non-void galaxies: baryonic mass, color, fractional stellar mass growth rate (FSMGR), morphology, and gas-to-stellar-mass ratio. The void galaxies typically have lower baryonic masses than galaxies in denser environments, and they display the properties expected of a lower mass population: they have more late-types, are bluer, have higher FSMGR, and are more gas rich. I also control for baryonic mass and investigate the extent to which void galaxies are different at fixed mass. I find that void galaxies are bluer, more gas-rich, and more star forming at fixed mass than non-void galaxies, which is a possible signature of galaxy assembly bias and other environmental processes. Furthermore, I show that these trends persist even at fixed mass and morphology, and I find that voids host a distinct population of early-types that are bluer and more star-forming than the typical red and quenched early-types. In addition to these empirical observational results, I also present theoretical results from mock catalogs with built-in galaxy assembly bias. I show that a simple matching of galaxy properties to (sub)halo properties, such as mass and age, can recover the observed environmental trends in the local galaxy population. In Chapter 3 (Florez et al. 2020, MNRAS, 497, 3273) I investigate the relation between AGN and star formation activity at 0.5 z 3 by analyzing 898 galaxies with high X-ray luminosity AGN (L [subscript X] 1044 erg s−1) and a large comparison sample of ~ 320,000 galaxies without such AGN. My samples are selected from a large (11.8 deg2) area in Stripe 82 that has multi-wavelength (X-ray to far-IR) data. The enormous comoving volume (~ 0.3 Gpc3) at 0.5
Integrated Spectral Energy Distributions Of Galaxies
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Author : Wells, III (Donald Carson)
language : en
Publisher:
Release Date : 1973
Integrated Spectral Energy Distributions Of Galaxies written by Wells, III (Donald Carson) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1973 with Galaxies categories.
Probing The Stellar Gaseous And Dust Properties Of Galaxies Through Analysis Of Their Spectral Energy Distributions
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Author : Rafael T. Eufrasio
language : en
Publisher:
Release Date : 2015
Probing The Stellar Gaseous And Dust Properties Of Galaxies Through Analysis Of Their Spectral Energy Distributions written by Rafael T. Eufrasio and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Galaxies categories.
The spectral energy distributions (SEDs) of galaxies are shaped by their physical properties and they are our primary source of information on galaxies stellar, gaseous, and dust content. Nearby galaxies (less than 100 Mpc away) are spatially resolved by current telescopes from the ultraviolet (UV) to radio wavelengths, allowing the study of the SEDs of subgalactic regions. Such studies are necessary for deriving maps and spatial trends of the physical properties across a galaxy. In principle, the complex history of the formation, growth, and evolution of a galaxy or a region of a galaxy can be inferred from its radiative output. In practice, this task is complicated by the fact that a significant fraction of the star formation activity takes place in dust obscured regions, in which a significant fraction of the stellar radiative output is absorbed, scattered, and reradiated by the gas and dust in the interstellar medium (ISM). This reprocessing of the stellar radiation takes place in ionized interstellar gas regions (H II regions) surrounding massive hot stars, in diffuse atomic gas (H I regions), and in dense molecular clouds. For this work, we have analyzed two galaxies in detail, NGC 6872 and NGC 6946, also known as Condor and Fireworks Galaxy, respectively. The Condor galaxy is the largest-known spiral galaxy. It is part a group of galaxies, the Pavo group, with 12 other galaxies. It has, however, interacted in the past ~150 Myr with a smaller companion, previously believed to have shaped the physical extent of the giant spiral. We have performed detailed SED fitting from the UV to mid-infrared (mid-IR) to obtain star formation histories of seventeen sub-galactic regions across the Condor. These regions are large enough to be galaxies themselves, with 32.3 million light-years in diameter. We find that the Condor was already very massive before this interaction and that it was much less affected by the passage of the companion than previously thought. We also found that a significant fraction of the 22 micron flux, usually considered a complementary measure of the UV-optically determined star formation rate (SFR), is not associated with the recent (last 100 Myr) star formation activity. A fraction of the 22 micron flux represents the energy reradiated by dust heated by intermediate age, long-lived stars. For the Fireworks galaxy, data coverage from the UV to radio allowed us to measure the full radiative budget from the stellar emission (bolometric luminosities) and the fraction coming from reprocessing by dust and gas in the IR. We present a self-consistent, physically-motivated model to describe SEDs of subgalactic regions across the galaxy, which simultaneously fits the stellar attenuated SED from UV to mid-infrared emission, the reradiated infrared emission from the dust, the radio continuum emission from the gas, as well as the intensity of select recombination lines from the ionized gas. We present a framework capable of determine the IR fraction not associated with the recent SFR. This work provides a novel and crucial step towards understanding the physical processes responsible for various empirical laws to determine SFR in galaxies, the correlation between the IR and stellar emission, and the physical conditions of the ISM. It provides essential inputs for more detailed modeling of the spatially-resolved photometric and chemical (dust and gas) evolution of galaxies.
Towards Understanding Galaxies At Large Redshift
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Author : Richard G. Kron
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06
Towards Understanding Galaxies At Large Redshift written by Richard G. Kron 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 2012-12-06 with Science categories.
This workshop was intended as an update and an extension of the workshop 011 the "Spectral Evolution of Galaxies" that was held in Erice two years ago. It concentrates 011 Ilew developments concerning galaxies seen at large look back times. This seemed also a good opportunity to look ahead to the next generation of ground- and space based instrumentation, and to consider various future strategies for collecting information concerning the edge of the observable universe. The main idea was to bring together people with specialities in modelling galaxy components (such as stars, clusters, gas, and dust) as well as whole stellar systems (stellar populations, star formation rates, chemical enrichment), and people specialized in making direct measurements of galaxies and clusters at large look back times. The confrontation of expectations and observations was planned to be the central theme of the conference, which explains the title "Towards Understanding Galaxies at Large Redshift". The first part of the workshop focussed on the physical processes that operate in galaxies, and that would likely have some observable manifestation at large redshifts. In the second part the most recent observational work was reported, and we were pleased to have the participation of most of the groups active in this field. The last part was directed towards new approaches to be made possible by the next generation of instrumentation, although in general all the contributions were indeed in this spirit of setting more ambitious goals.
Preliminary Findings Spectral Energy Distributions For Nearby E A Galaxies Using The Manga Survey
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Author : Olivia A. Weaver
language : en
Publisher:
Release Date : 2017
Preliminary Findings Spectral Energy Distributions For Nearby E A Galaxies Using The Manga Survey written by Olivia A. Weaver and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with Astronomy categories.
Proceedings Of The International Workshop On The Far Infrared And Submillimeter Spectral Energy Distributions Of Active And Starburst Galaxies
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Author : International Workshop on the Far Infrared and Submillimeter Spectral Energy Distributions of Active and Starburst Galaxies. 2000, Groningen
language : en
Publisher:
Release Date : 2001
Proceedings Of The International Workshop On The Far Infrared And Submillimeter Spectral Energy Distributions Of Active And Starburst Galaxies written by International Workshop on the Far Infrared and Submillimeter Spectral Energy Distributions of Active and Starburst Galaxies. 2000, Groningen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with categories.