Download or read book Exploring Star Formation in Cluster Galaxies written by K.V.S. Prasadh and published by . This book was released on 2018 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Exploring Star Formation in High mass Galaxies in the Low z Universe written by James Runge and published by . This book was released on 2018 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a quantitative analysis of high-mass, low-z galaxies in order to investigate the 'downsizing' scenario of galaxy evolution. High-mass, low-z galaxies with ongoing star formation, antithetical to the 'downsizing' model, are identified using the 22[micrometer] data (W4 band) from the Wide-field Infrared Survey Explorer (WISE). A cluster and field sample is chosen to investigate any possible environmental effects. The cluster sample is based upon the GMBCG catalog, which contains 55,424 brightest cluster galaxies (BCGs) at 0:1 [approximately less than] z [approximately less than] 0:55 identified in the Sloan Digital Sky Survey (SDSS). We identify 389 W4-detected BCGs (W4BCGs) that have median SFRs of [approximately]50 M[dot in circle]/yr based upon their total IR luminosity (L[subscript IR]), which is attributed to dust-enshrouded star formation. BCGs with such high SFRs are found in "coolcore" clusters and the star formation is thought to be fueled by a cooling flow." Using Chandra X-ray data, it is shown that a subset of BCGs do reside within coolcores, but their mass deposition rates cannot account for the SFR. For comparison, a field sample is drawn from the Max-Planck Institute for Astrophysics - John Hopkins University (MPA-JHU) "value-added" SDSS DR7 catalog of spectrum measurements. A set of 1,244 high-mass, elliptical field galaxies within the same redshift range as the W4BCG catalog are identified for comparison. The median mass for the field sample is lower than the W4BCGs (Log(M/M[dot in circle])=10.9 and 11.2 respectively), as are their SFRs. However, the specific star formation rate (sSFR), the star formation rate per stellar mass, is comparable for both groups (Log(sSFR)[approximately]-9.7). This possibly reveals that there is no environmental dependence on the sSFR for these W4-detected galaxies. While a possible mechanism responsible for the SFR was identified for the W4BCGs, the process responsible for the star formation in the field sample requires further investigation.
Download or read book Stars Gas and Dust in Galaxies written by Danielle M. Alloin and published by . This book was released on 2000 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Exploring the Star Formation Histories of Galaxies written by Eric Findlay Bell and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Exploring Star Formation in Dwarf Galaxies at Z1 written by Riona Ramraj and published by . This book was released on 2014 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigating the Impact of Group Environment on Galaxy Properties written by Stephania Barsanti and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The properties of galaxies, such as their shape and star formation rate (SFR), correclate strongly with the galaxy number density in the surrounding Universe. This is well known for cluster galaxies, which show a suppression of the star formation activity with respect to the field, but the situation is less clear for groups. The aim of this research is to explore whether and how the group environment may affectthe star formation properties of infalling star-forming galaxies. We use the Galaxy And Mass Assembly (GAMA) group catalogue, finding that the specific SFR of star-forming members declines at ~ 3.5 R200 towards the group centre by a factor ~ 1.3 with respect to field galaxies. We explore the use of the projected phase space (PPS) diagram, i.e. the galaxy velocity as a function of projected group-centric radius, as an environment metric in the group mass regime. The PPS has been extensively used for investigating more massive clusters where the position of a galaxy in the PPS correlates with time since infall. Similar to cluster studies, we find that the fraction of star-forming group galaxies is higher in the PPS regions dominated by recently accreted galaxies, whereas passive galaxies dominate the virialised regions.
Download or read book A Multiwavelength Exploration of Unexpected Star Formation Activity in SpARCS Brightest Cluster Galaxies written by Nina Bonaventura and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "In this thesis we present a comprehensive infrared photometric and optical spectroscopic analysis of the largest (716) and highest-redshift (z ~ 1.8) sample of Brightest Cluster Galaxies (BCGs), those selected from the Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS). The aim of this campaign was to determine the dominant physical mechanism(s) guiding the buildup of stellar mass in these most massive galaxies in the Universe. Given their unique habitat at the gravitational centres of the largest collapsed structures known, galaxy clusters, BCG formation and evolution is inextricably linked to the formation of large-scale structure in the Universe. In an effort to illuminate the true nature of this special class of galaxies and their relationship to their host clusters, we conducted an unprecedented analysis of their broadband, infrared spectral energy distributions (SEDs), utilising mid- and far-infrared imaging data (3.6-500 [mu]m) obtained by the NASA Spitzer and Herschel space telescopes. We also studied the optical spectroscopic data (3000-7000 Å) of a representative subsample (93/716) of SpARCS BCGs out to z=1.1 obtained with the ground-based Anglo-Australian Telescope. Through a comparison of the infrared BCG SEDs to a variety of SED model templates in the literature, we identify the major sources of their infrared energy output, in multiple redshift bins between 0 z
Download or read book Star Clusters written by B.W. Carney and published by Springer Science & Business Media. This book was released on 2006-04-18 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: Star clusters are at the heart of astronomy, being key objects for our understanding of stellar evolution and galactic structure. Observations with the Hubble Space Telescope and other modern equipment have revealed fascinating new facts about these galactic building blocks. This book provides two comprehensive and up-to-date, pedagogically designed reviews on star clusters by two well-known experts in the field. Bruce Carney presents our current knowledge of the relative and absolute ages of globular clusters and the chemical history of our Galaxy. Bill Harris addresses globular clusters in external galaxies and their use as tracers of galaxy formation and cosmic distance indicators. The book is written for graduate students as well as professionals in astronomy and astrophysics.
Download or read book Dynamics of Young Star Clusters and Associations written by Cathie Clarke and published by Springer. This book was released on 2015-09-11 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Where do most stars (and the planetary systems that surround them) in the Milky Way form? What determines whether a young star cluster remains bound (such as an open or globular cluster), or disperses to join the field stars in the disc of the Galaxy? These questions not only impact understanding of the origins of stars and planetary systems like our own (and the potential for life to emerge that they represent), but also galaxy formation and evolution, and ultimately the story of star formation over cosmic time in the Universe. This volume will help readers understand our current views concerning the answers to these questions as well as frame new questions that will be answered by the European Space Agency's Gaia satellite that was launched in late 2013. The book contains the elaborated notes of lectures given at the 42nd Saas-Fee Advanced Course “Dynamics of Young Star Clusters & Associations" by Cathie Clarke (University of Cambridge) who presents the theory of star formation and dynamical evolution of stellar systems, Robert Mathieu (University of Wisconsin) who discusses the kinematics of star clusters and associations, and I. Neill Reid (S pace Telescope Science Institute) who provides an overview of the stellar populations in the Milky Way and speculates on from whence came the Sun. As part of the Saas-Fee Advanced Course Series, the book offers an in-depth introduction to the field serving as a starting point for Ph.D. research and as a reference work for professional astrophysicists.
Download or read book Star Formation Galaxies and the Interstellar Medium written by Jose Franco and published by Cambridge University Press. This book was released on 1993-06-10 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Exploring the Limits of Star Formation from the Extreme Environment of Galaxy Interactions to the Milky Way written by Amanda Lea Heiderman and published by . This book was released on 2012 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, I explore the rate at which molecular gas is converted to stars through detailed studies of a sample of molecular clouds in the Milky Way, IFU spatially resolved observations of gas-rich nearby interacting galaxies, as well as the environmental dependence of star formation and galaxy morphology in a galaxy supercluster. This thesis is composed of three individual projects that investigate nearby star formation within the local 500 pc of our Sun, to neighboring extreme star forming environments of interacting starburst galaxies, and finally studying how star formation varies with galaxy morphology in a galaxy supercluster a z~0.165. I discuss the relation between the star formation rate (SFR) and molecular gas surface densities (e.g., Schmidt-Kennicutt relation) in Galactic star forming regions and find there is a discrepancy between my study and extragalactic relations. The discrepancy is attributed to extragalactic measurements that are averaged over large>kpc scales and include star forming molecular gas (above some threshold) and molecular gas the is not dense enough to form stars. I find a steep increase in the Galactic SFR-gas surface density relation indicative of a threshold for efficient star formation that is best fit to a broken power law with a linear slope above 129 Msun pc−2. I introduce the VIRUS-P Investigation of the eXtreme ENviroments of Starbursts (VIXENS) project which is a survey of interacting is a large integral field unit survey of nearby infrared bright (L_IR>3x1010 Lsun) interacting/starburst galaxies. The main goal of VIXENS is to investigate the relation between star formation and gas content on spatially resolved scales of ~0.1-1 kpc in the extreme star forming environments of interacting/starburst galaxies. The VIXENS sample is composed of systems in a range interaction stages with morphological signatures from early phase (close pairs) to late stage mergers (single system with multiple nuclei), SFRs, and gas surface densities. I highlight the first results from the VIXENS survey in the late interaction phase galaxy merger Arp 299. I find 1.3 kpc regions in Arp 299 to lie along the SFR-gas surface density relation found for mergers at high redshift, but this relation is highly dependent on the CO to molecular hydrogen (H2) conversion factor. I find evidence for a Galactic CO-to-H2 conversion factor using metallicity and dust temperature measurements, which would place 1.3 kpc regions in the Arp 299 merger in between the high redshift and Kennicutt-Schmidt relations. Comparing the SFR to dense gas surface densities as traced by HCN and HCO, I find an agreement between the spatially resolved measurements and that found on global scales in spirals and (ultra)luminous infrared galaxies. Finally, I present an investigation of the influence of environment on frequency, distribution, color, and star formation properties of galaxy mergers and non-interacting galaxies in the Abell 901/902 supercluster at z~0.165. I find galaxy mergers be preferentially blue in color and have an enhanced SFR by a factor of ~2 compared to non-interacting galaxies. This result may be due to a decrease in galaxy velocity dispersion in the cluster outskirt, favoring galaxy-galaxy interactions, or to interacting galaxies that are part of groups or field galaxies being accreted along cosmological filaments by the clusters. I compare to N-body simulations of groups and field galaxies accreting onto the clusters and find the fraction of mergers are similar to that predicated at group overdensities. I find the SFR of galaxies in the supercluster to be depressed compared to field galaxies in both the core and cluster outskirts, suggesting that an environmental process such as ram pressure stripping is effective throughout the cluster. The results of a modest SFR enhancement and a low merger fraction culminate in my finding that mergers contribute only a small fraction (between 10% and 15%) of the total SFR density of the Abell 901/902 clusters.
Download or read book Exploring Star Formation in High z Galaxies Using Atomic and Molecular Emission Lines written by Bitten Gullberg and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Exploring the History of Star Formation in Galaxies and Its Environmental Dependence at High Redshift written by Christopher C. Lovell and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Formation and Evolution of Star Clusters written by Kenneth Janes and published by . This book was released on 1991 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Formation of Stars and Star Clusters in Colliding Galaxies written by Pierre-Emmanuel Aime Marcel Belles and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Clusters of Galaxies Volume 3 Carnegie Observatories Astrophysics Series written by John S. Mulchaey and published by Cambridge University Press. This book was released on 2004-09-23 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: Series of review papers covering clusters of galaxies and related phenomena.
Download or read book The Evolution of Galaxies written by Marc Sauvage and published by Springer Science & Business Media. This book was released on 2002-07-31 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxies have a history. This has become clear from recent sky surveys which have shown that distant galaxies, formed early in the life of the Universe, differ from the nearby ones. New observational windows at ultraviolet, infrared and millimetric wavelengths (provided by ROSAT, IRAM, IUE, IRAS, ISO) have revealed that galaxies contain a wealth of components: very hot gas, atomic hydrogen, molecules, dust, dark matter ... A significant advance is expected due to new instruments (VLT, FIRST, XMM) which will allow one to explore the most distant Universe. Three Euroconferences have been planned to punctuate this new epoch in galactic research, bringing together specialists in various fields of Astronomy. The first one, held in Granada (Spain) in May 2000, addressed the observational clues. The second one took place in October 2001 in St Denis de la Réunion (France) and reviewed the basic building blocks and small-scale processes in galaxy evolution. The third one will take place in July 2002 in Kiel (Germany) and will be devoted to the overall modelling of galaxy evolution. This book contains the proceedings of the second conference. It is suitable for researchers and PhD students in Astrophysics.
