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1
White, Simon. "The influence of halo evolution on galaxy structure." Proceedings of the International Astronomical Union 10, H16 (2012): 371. http://dx.doi.org/10.1017/s1743921314011430.
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AbstractIf Einstein-Newton gravity holds on galactic and larger scales, then current observations demonstrate that the stars and interstellar gas of a typical bright galaxy account for only a few percent of its total nonlinear mass. Dark matter makes up the rest and cannot be faint stars or any other baryonic form because it was already present and decoupled from the radiation plasma at z = 1000, long before any nonlinear object formed. The weak gravito-sonic waves so precisely measured by CMB observations are detected again at z = 4 as order unity fluctuations in intergalactic matter. These subsequently collapse to form today's galaxy/halo systems, whose mean mass profiles can be accurately determined through gravitational lensing. High-resolution simulations link the observed dark matter structures seen at all these epochs, demonstrating that they are consistent and providing detailed predictions for all aspects of halo structure and growth. Requiring consistency with the abundance and clustering of real galaxies strongly constrains the galaxy-halo relation, both today and at high redshift. This results in detailed predictions for galaxy assembly histories and for the gravitational arena in which galaxies live. Dark halos are not expected to be passive or symmetric but to have a rich and continually evolving structure which will drive evolution in the central galaxy over its full life, exciting warps, spiral patterns and tidal arms, thickening disks, producing rings, bars and bulges. Their growth is closely related to the provision of new gas for galaxy building.
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Yee, H. K. C., M. J. Sawicki, R. G. Carlberg, et al. "The CNOC2 Field Galaxy Redshipt Survey." Highlights of Astronomy 11, no. 1 (1998): 460–63. http://dx.doi.org/10.1017/s153929960002178x.
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Fundamental to our understanding of the universe is the evolution of structures, from galaxies to clusters of galaxies to large-scale sheets and filaments of galaxies and voids. The investigation of the evolution of large-scale structure not only provides us with the key test of theories of structure formation, but also allows us to measure fundamental cosmological parameters. The CNOC2 (Canadian Network for Observational Cosmology) Field Galaxy Redshift Survey is the first large redshift survey of faint galaxies carried out with the explicit goal of investigating the evolution of large scale structure. This survey also provides the largest redshift and photometric data set currently available for the study of galaxy population and evolution at the moderate redshift range between 0.1 and 0.6. In this paper we describe the scope and technique of the survey, its status, and some preliminary results.
3
Maartens, Roy, José Fonseca, Stefano Camera, Sheean Jolicoeur, Jan-Albert Viljoen, and Chris Clarkson. "Magnification and evolution biases in large-scale structure surveys." Journal of Cosmology and Astroparticle Physics 2021, no. 12 (2021): 009. http://dx.doi.org/10.1088/1475-7516/2021/12/009.
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Abstract Measurements of galaxy clustering in upcoming surveys such as those planned for the Euclid and Roman satellites, and the SKA Observatory, will be sensitive to distortions from lensing magnification and Doppler effects, beyond the standard redshift-space distortions. The amplitude of these contributions depends sensitively on magnification bias and evolution bias in the galaxy number density. Magnification bias quantifies the change in the observed number of galaxies gained or lost by lensing magnification, while evolution bias quantifies the physical change in the galaxy number density relative to the conserved case. These biases are given by derivatives of the number density, and consequently are very sensitive to the form of the luminosity function. We give a careful derivation of the magnification and evolution biases, clarifying a number of results in the literature. We then examine the biases for a variety of surveys, encompassing galaxy surveys and line intensity mapping at radio and optical/near-infrared wavelengths.
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Robin, A. C., C. Reylé, and D. Marshall. "Modelling the Galaxy from survey data." Proceedings of the International Astronomical Union 3, S248 (2007): 443–49. http://dx.doi.org/10.1017/s1743921308019789.
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AbstractRecent optical and near-infrared surveys have considerably improved our knowledge of galactic structure and galactic evolution. Two ways can be used to infer this knowledge from datasets: either inversing the data to get parameters describing the Galaxy, or using a synthetic approaches to test scenarios of formation and theoretical models for star and galaxy formation and evolution, both approaches being complementary. Using the synthetic approach the Besancon Galaxy model allows to test scenarios for the structure and evolution of the Galaxy by comparing simulations with the survey data. Examples are given using the 2MASS survey. Future uses of astrometric survey data are shown to be able to efficiently constrain the kinematics and dynamics of the Galaxy.
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Nagai, Daisuke, Monique Arnaud, Sarthak Dasadia, Michael McDonald, Ikuyuki Mitsuishi, and Andrea Morandi. "Cluster Physics & Evolution." Proceedings of the International Astronomical Union 11, A29B (2015): 70–78. http://dx.doi.org/10.1017/s1743921316004543.
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AbstractRecent advances in X-ray and microwave observations have provided unprecedented insights into the structure and evolution of the hot X-ray emitting plasma from their cores to the virialization region in outskirts of galaxy clusters. Recent Sunyaev-Zel'dovich (SZ) surveys (ACT, Planck, SPT) have provided new cluster catalogs, significantly expanding coverage of the mass-redshift plane, whileChandraandXMM-NewtonX-ray follow-up programs have improved our understanding of cluster physics and evolution as well as the surveys themselves. However, the current cluster-based cosmological constraints are still limited by uncertainties in cluster astrophysics. In order to exploit the statistical power of the current and upcoming X-ray and microwave cluster surveys, it is critical to improve our understanding of the structure and evolution of the hot X-ray emitting intracluster medium (ICM). In this session, we discussed recent advances in observations and simulations of galaxy clusters, with highlights on (i) the evolution of ICM profiles and scaling relations, (ii) physical processes operating in the outskirts of galaxy clusters, and (iii) impact of mergers on the ICM structure in groups and clusters.
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Conselice, Christopher J. "The Evolution of Galaxy Structure Over Cosmic Time." Annual Review of Astronomy and Astrophysics 52, no. 1 (2014): 291–337. http://dx.doi.org/10.1146/annurev-astro-081913-040037.
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Gilmore, Gerard, and Rosemary F. G. Wyse. "Structure and Evolution of the Milky Way Galaxy." International Astronomical Union Colloquium 111 (1989): 83–102. http://dx.doi.org/10.1017/s0252921100011465.
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AbstractThe combination of chemical abundance, kinematic, and age data for stars near the sun provides important information about the early evolution of the Galaxy. We review available data, with some new analysis, to show that the sum of all available information strongly suggests that the extreme population II subdwarf system formed during a period of rapid collapse of the proto-Galaxy. This subdwarf system now forms a flattened, pressure-supported distribution, with axial ratio ∼2:1. The thick disk formed subsequent to the subdwarf system. At least the metal-poor tail of the thick disk is comparable in age to the globular cluster system. The thick disk is probably kinematically discrete from the Galactic old disk, though the data remain inadequate for robust conclusions.
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Gilmore, Gerard, and Rodrigo Ibata. "Large Scale Galactic Structure." International Astronomical Union Colloquium 148 (1995): 258–66. http://dx.doi.org/10.1017/s0252921100022004.
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AbstractModern models of Galaxy formation make fairly specific predictions which are amenable to detailed tests with galactic kinematic and chemical abundance data. For example, popular Cold Dark Matter models ‘predict’ growth of the Galaxy about a central core, which should contain the oldest stars. Later accretion of material forms the outer halo and the disks, while continuing accretion will continue to affect the kinematic structure of both the outer halo and the thin disk. This picture, which contains aspects of both the monolithic (‘ELS’) and the multifragment (‘Searle-Zinn’) pictures often discussed in chemical evolution models, makes some specific predictions which can be tested. The essential feature of these predictions is that they are believable only for the largest scale effects. Large scale properties of the Galaxy must be measured to test them. It is these studies which need large angular scale data. One specific example of current interest is the ‘prediction’ that mergers of small satellites are an essential feature of galactic evolution. This leads one to look for kinematic and spatial structures, and ‘moving groups’, as a primary test of such models.
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Mazzei, P., A. Marino, R. Rampazzo, H. Plana, M. Rosado, and L. Arias. "Galaxy evolution in groups." Astronomy & Astrophysics 610 (February 2018): A8. http://dx.doi.org/10.1051/0004-6361/201731182.
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Context. Local Group (LG) analogs (LGAs) are galaxy associations dominated by a few bright spirals reminiscent of the LG. The NGC 3447/NGC 3447A system is a member of the LGG 225 group, a nearby LGA. This system is considered a physical pair composed of an intermediate-luminosity late-type spiral, NGC 3447 itself, and an irregular companion, NGC 3447A, linked by a faint, short filament of matter. A ring-like structure in the NGC 3447 outskirts has been emphasised by Galaxy Evolution Explorer (GALEX) observations. Aims. This work aims to contribute to the study of galaxy evolution in low-density environments, a favourable habitat to highly effective encounters, shedding light on the evolution of the NGC 3447/NGC 3447A system. Methods. We performed a multi-λ analysis of the surface photometry of this system to derive its spectral energy distribution and structural properties using ultraviolet (UV), Swift UVOT, and optical Sloan Digital Sky Survey (SDSS) images complemented with available far-IR observations. We also characterised the velocity field of the pair using two-dimensional Hα kinematical observations of the system obtained with PUMA Fabry-Perot interferometer at the 2.1 m telescope of San Pedro Mártir (Mexico). All these data are used to constrain smooth particle hydrodynamic simulations with chemo-photometric implementation to shed light on the evolution of this system. Results. The luminosity profiles, from UV to optical wavelengths, are all consistent with the presence of a disc extending and including NGC 3447A. The overall velocity field does not emphasise any significant rotation pattern, rather a small velocity gradient between NGC 3447 and NGC 3447A. Our simulation, detached from a large grid explored to best-fit the global properties of the system, suggests that this arises from an encounter between two halos of equal mass. Conclusions. NGC 3447 and NGC 3447A belong to the same halo, NGC 3447A being a substructure of the same disk including NGC 3447. The halo gravitational instability, enhanced by the encounter, fuels a long-lived instability in this dark-matter-dominated disk, driving the observed morphology. The NGC 3447/NGC 3447A system may warn of a new class of “false pairs” and the potential danger of a misunderstanding of such objects in pair surveys that could produce a severe underestimate of the total mass of a system.
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Keenan, Olivia C., Jonathan I. Davies, Rhys Taylor, and Robert F. Minchin. "The Structure of Halo Gas around M33." Proceedings of the International Astronomical Union 11, S321 (2016): 244–47. http://dx.doi.org/10.1017/s1743921316011455.
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AbstractUnderstanding the distribution of gas in and around galaxies is vital for our interpretation of galaxy formation and evolution. As part of the Arecibo Galaxy Environment Survey (AGES) we have observed the neutral hydrogen (HI) gas in and around the nearby Local Group galaxy M33 to a greater depth than previous observations. As part of this project we investigated the absence of optically detected dwarf galaxies in its neighbourhood, which is contrary to predictions of galaxy formation models. We observed 22 discrete clouds, 11 of which were previously undetected and none of which have optically detected counterparts. We find one particularly interesting hydrogen cloud, which has many similar characteristics to hydrogen distributed in the disk of a galaxy. This cloud, if it is at the distance of M33, has a HI mass of around 107 M⊙ and a diameter of 18 kpc, making it larger in size than M33 itself.
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Vesperini, Enrico. "Evolution of Globular Cluster Systems in Elliptical Galaxies." Symposium - International Astronomical Union 207 (2002): 664–72. http://dx.doi.org/10.1017/s0074180900224509.
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We study the evolution of the main properties of globular cluster systems in elliptical galaxies. In particular, we focus our attention on the evolution of the mass function of globular cluster systems (GCMF), on the fraction of surviving clusters and on the ratio of the final to initial total mass in clusters and we explore the dependence of these properties on the structure of the host galaxy and on the initial GCMF. We show that the observed universality of the GCMF parameters in galaxies with different structures can be reconciled with the effects of evolutionary processes and with the significant differences in the efficiency of evolutionary processes in different host galaxies; the final mean masses of globular cluster systems in massive galaxies can be very similar to each other with a small galaxy-to-galaxy dispersion in spite of large differences in the fraction of surviving clusters.
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Linke, Laila, Patrick Simon, Peter Schneider, et al. "KiDS+VIKING+GAMA: Testing semi-analytic models of galaxy evolution with galaxy–galaxy–galaxy lensing." Astronomy & Astrophysics 640 (August 2020): A59. http://dx.doi.org/10.1051/0004-6361/202038355.
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Context. Several semi-analytic models (SAMs) try to explain how galaxies form, evolve, and interact inside the dark matter large-scale structure. These SAMs can be tested by comparing their predictions for galaxy–galaxy–galaxy lensing (G3L), which is weak gravitational lensing around galaxy pairs, with observations. Aims. We evaluate the SAMs by Henriques et al. (2015, MNRAS, 451, 2663, hereafter H15) and by Lagos et al. (2012, MNRAS, 426, 2142, hereafter L12), which were implemented in the Millennium Run, by comparing their predictions for G3L to observations at smaller scales than previous studies and also for pairs of lens galaxies from different populations. Methods. We compared the G3L signal predicted by the SAMs to measurements in the overlap of the Galaxy And Mass Assembly survey (GAMA), the Kilo-Degree Survey (KiDS), and the VISTA Kilo-degree Infrared Galaxy survey (VIKING) by splitting lens galaxies into two colour and five stellar-mass samples. Using an improved G3L estimator, we measured the three-point correlation of the matter distribution with “mixed lens pairs” with galaxies from different samples, and with “unmixed lens pairs” with galaxies from the same sample. Results. Predictions by the H15 SAM for the G3L signal agree with the observations for all colour-selected samples and all but one stellar-mass-selected sample with 95% confidence. Deviations occur for lenses with stellar masses below 9.5 h−2 M⊙ at scales below 0.2 h−1 Mpc. Predictions by the L12 SAM for stellar-mass selected samples and red galaxies are significantly higher than observed, while the predicted signal for blue galaxy pairs is too low. Conclusions. The L12 SAM predicts more pairs of low stellar mass and red galaxies than the H15 SAM and the observations, as well as fewer pairs of blue galaxies. This difference increases towards the centre of the galaxies’ host halos. Likely explanations are different treatments of environmental effects by the SAMs and different models of the initial mass function. We conclude that G3L provides a stringent test for models of galaxy formation and evolution.
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Walton, Nicholas A., Janet E. Drew, Eduardo A. Gonzalez-Solares, Robert Greimel, Ella C. Hopewell, and Mike J. Irwin. "Mapping Galactic spiral arm structure: the IPHAS survey and Virtual Observatory access." Proceedings of the International Astronomical Union 2, no. 14 (2006): 595. http://dx.doi.org/10.1017/s1743921307011933.
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There is now considerable interest in how stellar streams in the Milky Way can be used to probe how the earlier merger history of our galaxy, which in turn can be related to hierarchical models of galaxy evolution.
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Javadi, Atefeh, and Jacco Th van Loon. "AGB population as probes of galaxy structure and evolution." Proceedings of the International Astronomical Union 14, S343 (2018): 283–90. http://dx.doi.org/10.1017/s1743921318006671.
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AbstractThe evolution of galaxies is driven by the birth and death of stars. AGB stars are at the end points of their evolution and therefore their luminosities directly reflect their birth mass; this enables us to reconstruct the star formation history. These cool stars also produce dust grains that play an important role in the temperature regulation of the interstellar medium (ISM), chemistry, and the formation of planets. These stars can be resolved in all of the nearby galaxies. Therefore, the Local Group of galaxies offers us a superb near-field cosmology site. Here we can reconstruct the formation histories, and probe the structure and dynamics, of spiral galaxies, of the many dwarf satellite galaxies surrounding the Milky Way and Andromeda, and of isolated dwarf galaxies. It also offers a variety of environments in which to study the detailed processes of galaxy evolution through studying the mass-loss mechanism and dust production by cool evolved stars. In this paper, I will first review our recent efforts to identify mass-losing Asymptotic Giant Branch (AGB) stars and red supergiants (RSGs) in Local Group galaxies and to correlate spatial distributions of the AGB stars of different mass with galactic structures. Then, I will outline our methodology to reconstruct the star formation histories using variable pulsating AGB stars and RSGs and present the results for rates of mass–loss and dust production by pulsating AGB stars and their analysis in terms of stellar evolution and galaxy evolution.
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Xu, Zeyue. "Galaxy formation and evolution." Theoretical and Natural Science 11, no. 1 (2023): 59–64. http://dx.doi.org/10.54254/2753-8818/11/20230381.
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Galaxies as the most important structures in the universe and Galaxy formation is a sequential redistribution process.The basic picture of galaxy formation was first proposed by White and Rees.The physical processes involved in galaxy formation are very numerous and complex. We know very little about most of these processes. Therefore, we can only describe them with a few empirical formulas. In this article the popular simulation techniques for galaxy formation are discussed in detail, based on the most recently observed cosmic star formation history. This study will focus mostly on the goals of galaxy development by describing the processes of star formation, gas dispersion, dark matter, and galaxy correlation. In this paper, we do not study the formation process of a specific galaxy, but focus on the formation process of a large sample of galaxies in the framework of the whole cosmology We are also concerned not with the specific properties of a particular galaxy, but with the statistical properties of the whole sample of galaxies.Therefore the paper will next explore hydrodynamic techniques such as N-body simulation, other modified f (R) gravity models, smoothed-particle hydrodynamic simulation, and semi-analytic models to mimic the process of galaxy formation. This article finishes with a summary of galaxy formation.
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West, Michael J., Roberto De Propris, Maret Einasto, Z. L. Wen, and J. L. Han. "Evolution of Cluster Alignments as Evidence of Large-scale Structure Formation in the Universe." Astrophysical Journal Letters 987, no. 2 (2025): L24. https://doi.org/10.3847/2041-8213/ade66d.
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Abstract The Universe’s large-scale structure forms a vast, interconnected network of filaments, sheets, and voids known as the cosmic web. For decades, astronomers have observed that the orientations of neighboring galaxy clusters within these elongated structures are often aligned over separations of tens of Mpc. Using the largest available catalog of galaxy clusters, we show for the first time that cluster orientations are correlated over even larger scales—up to 200–300 comoving Mpc—and such alignments are seen to redshifts of at least z ≃ 1. Comparison with numerical simulations suggests that coherent structures on similar scales may be expected in ΛCDM models.
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Gerhard, Ortwin. "Perspectives on Galactic Structure." Proceedings of the International Astronomical Union 13, S336 (2017): 147. http://dx.doi.org/10.1017/s1743921317010286.
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The Milky Way is currently the subject of great observational effort. This includes both ESA's unique Gaia mission, as well as a multitude of ground-based surveys. Several of these are already returning data of unprecedented depth and quality for large numbers of Milky Way stars. These new data are likely to lead to a quantum step in our understanding of Milky Way structure and evolution. Because the new data will allow us to study our Galaxy at much greater resolution than possible in other galaxies, we also expect to greatly improve our understanding of disk galaxy formation in general.
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Feast, M. W. "Mira Variables, Stellar Evolution and Galactic Structure." International Astronomical Union Colloquium 111 (1989): 205–13. http://dx.doi.org/10.1017/s0252921100011532.
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The Mira variables make important contributions to four of the main problems under discussion at this meeting, (1) stellar pulsation, (2) stellar evolution, (3) the morphology and history of the Galaxy, (4) the comparative study of different galaxies. The Miras also show how these rather different fields of study overlap, so that it is no longer possible to deal with any one field in isolation.
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Tolasa, Diriba Gonfa. "Exploring the Formation, Dynamics, and Structure of Galaxy Clusters: A Comprehensive Analysis." Acceleron Aerospace Journal 4, no. 1 (2025): 831–46. https://doi.org/10.61359/11.2106-2503.
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This study explores the formation, structure, and dynamics of galaxy groups and clusters, highlighting their significance in the cosmic web. Galaxy clusters are massive, self-gravitating systems that display complex interactions influenced by dark matter and the intracluster medium (ICM). Recent advancements in X-ray and optical observations have significantly improved our understanding of the morphology and kinematics of these clusters, shedding light on the processes governing their evolution. The research employs the virial theorem to determine mass distributions and examines gravitational lensing effects to probe the mysterious nature of dark matter. Key challenges addressed include understanding how galaxy clusters form, analyzing the dynamics of the galaxies within them, and identifying the missing mass that holds these structures together. By combining observational data with theoretical models, this investigation aims to enhance our comprehension of the Universe's large-scale structure and the fundamental forces driving galaxy group dynamics.
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Lucatelli, Geferson, Fabricio Ferrari, Arianna Cortesi, et al. "Curvature of galaxy brightness profiles." Proceedings of the International Astronomical Union 15, S359 (2020): 444–45. http://dx.doi.org/10.1017/s1743921320002318.
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AbstractGalaxy morphologies reflect the shapes of galaxies and their structural components, such as bulges, discs, bars, spiral arms, etc. The detailed knowledge of the morphology of a galaxy provides understanding of the physics behind its evolution, since the time of its formation, including interaction processes and influence of the environment. Thus, the more precisely we can describe a galaxy structure, the more we may understand about its formation and evolution. We present a method that measures curvature, using images, to describe galaxy structure and to infer the morphology of each component of a galaxy. We also include some preliminary results of curvature measurements for galaxies of the Southern Photometric Local Universe Survey (S-PLUS) DR1 data release and for jellyfish galaxies of the Omega Survey. We find that the median of the curvature parameter and the integrated area under the curvature give us clues on the morphology of a galaxy.
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Komossa, S., J. G. Baker, and F. K. Liu. "Growth of Supermassive Black Holes, Galaxy Mergers and Supermassive Binary Black Holes." Proceedings of the International Astronomical Union 11, A29B (2015): 292–98. http://dx.doi.org/10.1017/s1743921316005378.
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AbstractThe study of galaxy mergers and supermassive binary black holes (SMBBHs) is central to our understanding of the galaxy and black hole assembly and (co-)evolution at the epoch of structure formation and throughout cosmic history. Galaxy mergers are the sites of major accretion episodes, they power quasars, grow supermassive black holes (SMBHs), and drive SMBH-host scaling relations. The coalescing SMBBHs at their centers are the loudest sources of gravitational waves (GWs) in the Universe, and the subsequent GW recoil has a variety of potential astrophysical implications which are still under exploration. Future GW astronomy will open a completely new window on structure formation and galaxy mergers, including the direct detection of coalescing SMBBHs, high-precision measurements of their masses and spins, and constraints on BH formation and evolution in the high-redshift Universe.
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Nasution, Budiman, Ruben Cornelius Siagian, Winsyahputra Ritonga, Lulut Alfaris, Aldi Cahya Muhammad, and Arip Nurahman. "A Monte Carlo Density Distribution Model Study to Analyze Galaxy Structure, Mass Distribution, and Dark Matter Phenomena." Indonesian Review of Physics 6, no. 1 (2023): 24–44. http://dx.doi.org/10.12928/irip.v6i1.8240.
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This research uses the Monte Carlo density distribution model to study the structure and mass distribution of galaxies and the dark matter phenomenon. Through computer simulations, the research developed a mathematical model with parameters such as rho0, rc, beta, and others, to describe the structure and mass distribution of galaxies. The results show that the model can reproduce various galaxy structures, including groups, clusters and filaments, and influence the behavior and characteristics of individual galaxies. This research provides a deeper understanding of dark matter and its impact on the evolution of the universe. It has implications for improving our understanding of dark matter and the use of Monte Carlo density distribution models to study galaxies. This study provides new insights into the evolution of galaxies and their relationship with dark matter in cosmology. Using both physics and mathematical concepts, this research helps to understand the phenomenon of dark matter and the structure of galaxies, and provides a basis for further research on dark matter and galaxy evolution.
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Gouin, C., N. Aghanim, V. Bonjean, and M. Douspis. "Probing the azimuthal environment of galaxies around clusters." Astronomy & Astrophysics 635 (March 2020): A195. http://dx.doi.org/10.1051/0004-6361/201937218.
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Galaxy clusters are connected at their peripheries to the large-scale structures by cosmic filaments that funnel accreting material. These filamentary structures are studied to investigate both environment-driven galaxy evolution and structure formation and evolution. In the present work, we probe in a statistical manner the azimuthal distribution of galaxies around clusters as a function of the cluster-centric distance, cluster richness, and star-forming or passive galaxy activity. We performed a harmonic decomposition in large photometric galaxy catalogue around 6400 SDSS clusters with masses M > 1014 solar masses in the redshift range of 0.1 < z < 0.3. The same analysis was performed on the mock galaxy catalogue from the light cone of a Magneticum hydrodynamical simulation. We used the multipole analysis to quantify asymmetries in the 2D galaxy distribution. In the inner cluster regions at R < 2R500, we confirm that the galaxy distribution traces an ellipsoidal shape, which is more pronounced for richest clusters. In the outskirts of the clusters (R = [2 − 8]R500), filamentary patterns are detected in harmonic space with a mean angular scale mmean = 4.2 ± 0.1. Massive clusters seem to have a larger number of connected filaments than lower-mass clusters. We also find that passive galaxies appear to trace the filamentary structures around clusters better. This is the case even if the contribution of star-forming galaxies tends to increase with the cluster-centric distance, suggesting a gradient of galaxy activity in filaments around clusters.
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Masters, Karen L. "Galaxy Zoo 3D: Identifying Bars, Spirals and Foreground Stars in MaNGA Galaxy Data." Proceedings of the International Astronomical Union 17, S373 (2021): 39–41. http://dx.doi.org/10.1017/s1743921322004306.
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AbstractGalaxies, particularly disc galaxies, show a wide variety of internal structures (e.g. spirals, bars, and bulges). Mapping Nearby Galaxies at Apache Point Observatory (MaNGA, part of the fourth incarnation of the Sloan Digital Sky Surveys), obtained spatially resolved spectral maps for 10,010 nearby galaxies. Many results from MaNGA have collapsed this structure into azimuthally averaged radial gradients, or symmetric 2D shapes, but there is significantly more information about the effect internal structures have on the evolution of galaxies available if we can identify different internal structures. One of the simplest ways to identify irregular internal structures in galaxies is by visual inspection. By employing a citizen science technique to ask this question of N independent volunteers we have obtained quantitatively robust masks (and errors) for spirals and bars in MaNGA target galaxies. In addition to internal features the interface asked users to identify foreground stars and foreground/background galaxies.
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Porqueres, Natàlia, Jens Jasche, Torsten A. Enßlin, and Guilhem Lavaux. "Imprints of the large-scale structure on AGN formation and evolution." Astronomy & Astrophysics 612 (April 2018): A31. http://dx.doi.org/10.1051/0004-6361/201732141.
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Black hole masses are found to correlate with several global properties of their host galaxies, suggesting that black holes and galaxies have an intertwined evolution and that active galactic nuclei (AGN) have a significant impact on galaxy evolution. Since the large-scale environment can also affect AGN, this work studies how their formation and properties depend on the environment. We have used a reconstructed three-dimensional high-resolution density field obtained from a Bayesian large-scale structure reconstruction method applied to the 2M++ galaxy sample. A web-type classification relying on the shear tensor is used to identify different structures on the cosmic web, defining voids, sheets, filaments, and clusters. We confirm that the environmental density affects the AGN formation and their properties. We found that the AGN abundance is equivalent to the galaxy abundance, indicating that active and inactive galaxies reside in similar dark matter halos. However, occurrence rates are different for each spectral type and accretion rate. These differences are consistent with the AGN evolutionary sequence suggested by previous authors, Seyferts and Transition objects transforming into low-ionization nuclear emission line regions (LINERs), the weaker counterpart of Seyferts. We conclude that AGN properties depend on the environmental density more than on the web-type. More powerful starbursts and younger stellar populations are found in high densities, where interactions and mergers are more likely. AGN hosts show smaller masses in clusters for Seyferts and Transition objects, which might be due to gas stripping. In voids, the AGN population is dominated by the most massive galaxy hosts.
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Bartelmann, Matthias, Klaus Dolag, and Harald Lesch. "The Evolution of Magnetic Fields in Galaxy Clusters." Symposium - International Astronomical Union 208 (2003): 189–98. http://dx.doi.org/10.1017/s0074180900207146.
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Cosmological simulations of magnetic fields in galaxy clusters show that remarkable agreement between simulations and observations of Faraday rotation and radio haloes can be achieved assuming that seed fields of ∼ 10−9 G were present at redshifts ∼ 15−20. The structure of the seed field is irrelevant for the final intracluster field. On average, the field grows exponentially with decreasing cluster redshift, but merger events cause steep transient increases in the field strength. Typical field-reversal scales are of order 50h−1kpc. In most cases, the intracluster fields are dynamically unimportant. Assuming secondary electron models, the average structure of cluster radio haloes can naturally be reproduced.
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Martig, Marie, Frédéric Bournaud, and Romain Teyssier. "Numerical simulations of galaxy evolution in cosmological context." Proceedings of the International Astronomical Union 4, S254 (2008): 429–34. http://dx.doi.org/10.1017/s1743921308027920.
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AbstractLarge volume cosmological simulations succeed in reproducing the large-scale structure of the Universe. However, they lack resolution and may not take into account all relevant physical processes to test if the detail properties of galaxies can be explained by the CDM paradigm. On the other hand, galaxy-scale simulations could resolve this in a robust way but do not usually include a realistic cosmological context.To study galaxy evolution in cosmological context, we use a new method that consists in coupling cosmological simulations and galactic scale simulations. For this, we record merger and gas accretion histories from cosmological simulations and re-simulate at very high resolution the evolution of baryons and dark matter within the virial radius of a target galaxy. This allows us for example to better take into account gas evolution and associated star formation, to finely study the internal evolution of galaxies and their disks in a realistic cosmological context.We aim at obtaining a statistical view on galaxy evolution from z ≃ 2 to 0, and we present here the first results of the study: we mainly stress the importance of taking into account gas accretion along filaments to understand galaxy evolution.
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Fujita, Yutaka, Keiichi Umetsu, Elena Rasia, et al. "The new fundamental plane dictating galaxy cluster evolution." Proceedings of the International Astronomical Union 15, S341 (2019): 271–72. http://dx.doi.org/10.1017/s1743921319001376.
Texte intégralRésumé :
AbstractIn this study, we show that the characteristic radius rs, mass Ms, and the X-ray temperature, TX, of galaxy clusters form a thin plane in the space of (log rs, log Ms, log TX). This tight correlation indicates that the cluster structure including the temperature is affected by the formation time of individual clusters. Numerical simulations show that clusters move along the fundamental plane as they evolve. The plane and the cluster evolution within the plane can be explained by a similarity solution of structure formation. The angle of the plane shows that clusters have not achieved “virial equilibrium”. The details of this study are written in Fujita et al. (2018a,b).
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Friedman-Shaw, Batia, Alex Krolewski, Matteo Foglieni, and Niayesh Afshordi. "Doppler bias: impact of peculiar velocities on color selection and the large scale structure of galaxy surveys." Journal of Cosmology and Astroparticle Physics 2025, no. 03 (2025): 059. https://doi.org/10.1088/1475-7516/2025/03/059.
Texte intégralRésumé :
Abstract Lightcone selection effects on cosmic observables must be precisely accounted for in the next generation of surveys, including the Dark Energy Spectroscopic Instrument (DESI) survey. This will allow us to correctly model the data and extract subtle shifts from general-relativistic effects. We examine the effects of peculiar velocities on color selection in spectroscopic galaxy surveys, with a focus on their implications for the galaxy clustering dipole P 1(k). Using DESI Emission Line Galaxy (ELG) targets, we show that peculiar velocities can shift spectral emission features into or out of filter bands, modifying galaxy colors and thereby changing galaxy selection. This phenomenon mimics the effect of evolution bias, and we refer to it as the Doppler bias, bD . The Doppler bias is of comparable size to the evolution bias at 0.8 < z < 1, where it is largest. This enhances the ELG-LRG (Luminous Red Galaxy) cross-correlation dipole by 25–50%. This could be detectable at the ∼ 6σ level for the full DESI survey. Additionally, we found that our bD estimate is impacted by the incompleteness of the parent ELG sample. Therefore, this work highlights the essential need for careful consideration of spectral-dependent biases caused by peculiar velocities during the selection phase of galaxy surveys, to enable unbiased analyses.
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Wenger, Trey V., Dana S. Balser, L. D. Anderson, and T. M. Bania. "Structure in the Milky Way." Proceedings of the International Astronomical Union 13, S334 (2017): 381–82. http://dx.doi.org/10.1017/s1743921317007578.
Texte intégralRésumé :
AbstractThe morphological and chemical structure of the Milky Way today is an important constraint on models of the formation and evolution of the Galaxy. We use H ii regions, the sites of recent massive star formation, to probe both the Galactic spiral structure and the Galactic metallicity structure. H ii regions are the brightest objects in the Galaxy at radio wavelengths and are detected across the entire Galactic disk. We derive the distances to H ii regions using parallax measurements or by deriving kinematic distances. Here we summarize ongoing work to assess the accuracy of kinematic distances and to complete the census of Galactic H ii regions in the Southern sky.
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Linke, Laila, Patrick Simon, Peter Schneider, and Stefan Hilbert. "Measuring galaxy-galaxy-galaxy-lensing with higher precision and accuracy." Astronomy & Astrophysics 634 (January 29, 2020): A13. http://dx.doi.org/10.1051/0004-6361/201936693.
Texte intégralRésumé :
Context. Galaxy-galaxy-galaxy lensing (G3L) is a powerful tool for constraining the three-point correlation between the galaxy and matter distribution and thereby models of galaxy evolution. Aims. We propose three improvements to current measurements of G3L: (i) a weighting of lens galaxies according to their redshift difference, (ii) adaptive binning of the three-point correlation function, and (iii) accounting for the effect of lens magnification by the cosmic large-scale structure. Improvement (i) is designed to improve the precision of the G3L measurement, whereas improvements (ii) and (iii) remove biases of the estimator. We further show how the G3L signal can be converted from angular into physical scales. Methods. The improvements were tested on simple mock data and simulated data based on the Millennium Run with an implemented semi-analytic galaxy model. Results. Our improvements increase the signal-to-noise ratio by 35% on average at angular scales between 0.′1 and 10′ and physical scales between 0.02 and 2 h−1 Mpc. They also remove the bias of the G3L estimator at angular scales below 1′, which was originally up to 40%. The signal due to lens magnification is approximately 10% of the total signal.
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Quillen, Alice C., and Ivan Minchev. "Non-equilibrium Dynamical Processes in the Galaxy." Proceedings of the International Astronomical Union 5, H15 (2009): 178–79. http://dx.doi.org/10.1017/s1743921310008604.
Texte intégralRésumé :
AbstractDynamical models have often necessarily assumed that the Galaxy is nearly steady state or dynamically relaxed. However observed structure in the stellar metallicity, spatial and velocity distributions imply that heating, mixing and radial migration has taken place. Better comprehension of non-equilibrium processes will allow us to not only better understand the current structure of the galaxy but its past evolution.
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Sjouwerman, Loránt O., Ylva M. Pihlström, Michael C. Stroh, et al. "BAaDE: The Bulge Asymmetries and Dynamical Evolution survey." Proceedings of the International Astronomical Union 14, S353 (2019): 45–46. http://dx.doi.org/10.1017/s1743921319008147.
Texte intégralRésumé :
AbstractThe Bulge Asymmetries and Dynamical Evolution (BAaDE) survey aims to use circumstellar SiO maser line-of-sight velocities as probes for the Galactic gravitational potential and dynamical structure. The SiO masers are detected at a high rate in specific color-selected MSX infrared sources. Furthermore, the SiO maser properties and line ratios, in combination with infrared spectral energy distributions and location in the Galaxy, will statistically yield detailed information on population and evolution of low- to intermediate-mass evolved stars in the Galaxy.
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Petersen, Michael S., Martin D. Weinberg, and Neal Katz. "Using commensurabilities and orbit structure to understand barred galaxy evolution." Monthly Notices of the Royal Astronomical Society 500, no. 1 (2020): 838–58. http://dx.doi.org/10.1093/mnras/staa3202.
Texte intégralRésumé :
ABSTRACT We interpret simulations of secularly evolving disc galaxies through orbit morphology. Using a new algorithm that measures the volume of orbits in real space using a tessellation, we rapidly isolate commensurate (resonant) orbits. We identify phase-space regions occupied by different orbital families. Compared to spectral methods, the tessellation algorithm can identify resonant orbits within a few dynamical periods, crucial for understanding an evolving galaxy model. The flexible methodology accepts arbitrary potentials, enabling detailed descriptions of the orbital families. We apply the machinery to four different potential models, including two barred models, and fully characterize the orbital membership. We identify key differences in the content of orbit families, emphasizing the presence of orbit families indicative of the bar evolutionary state and the shape of the dark matter halo. We use the characterization of orbits to investigate the shortcomings of analytic and self-consistent studies, comparing our findings to the evolutionary epochs in self-consistent barred galaxy simulations. Using insight from our orbit analysis, we present a new observational metric that uses spatial and kinematic information from integral field spectrometers that may reveal signatures of commensurabilities and allow for a differentiation between models.
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Foëx, Gaël, Veronica Motta, Marceau Limousin, Tomas Verdugo, and Fabio Gastaldello. "Studying structure formation and evolution with strong-lensing galaxy groups." Proceedings of the International Astronomical Union 11, S308 (2014): 211–12. http://dx.doi.org/10.1017/s1743921316009881.
Texte intégralRésumé :
AbstractWe present the analysis of a sample of strong-lensing galaxy group candidates. Our main findings are: confirmation of group-scale systems, complex light distributions, presence of large-scale structures in their surroundings, and evidence of a strong-lensing bias in the mass-concentration relation. We also report the detection of the first 'Bullet group'.
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Dolag, K., M. Bartelmann, and H. Lesch. "Evolution and structure of magnetic fields in simulated galaxy clusters." Astronomy & Astrophysics 387, no. 2 (2002): 383–95. http://dx.doi.org/10.1051/0004-6361:20020241.
Texte intégral
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Anosova, J., and G. F. Benedict. "Dynamical Explorations of Nuclear Structures in Barred Galaxies." Symposium - International Astronomical Union 186 (1999): 348. http://dx.doi.org/10.1017/s0074180900112951.
Texte intégralRésumé :
NGC 4314 (Benedict et al. 1996) has a complex nuclear morphology with recent star formation confined to a nuclear ring. HST observations resolve the nuclear ring into multiple sites of new star formation and resolve the associated dust lanes into discrete clouds. We construct dynamical models of this galaxy in order to provide plausible identification of the dynamical processes that led to the formation of the observed structure. We assume that the center of this galaxy contains a very massive double black-hole, surrounded by relatively low-mass particles - the star clusters as well as gas and dust complexes. Our previous work (Anosova & Anandarao 1994, Anosova & Tanikawa 1995) showed that the dynamical evolution of such a model produces many structures similar to those observed in galaxies of diverse types: spiral and elliptical galaxies, interacting galaxies, and various types of flows and jets. In the present work, we consider a number of such models with different initial parameters. We study their dynamical evolution of the gravitational N-body problem, taking into account strong interactions of bodies. Comparison of the evolution of our models with the observed structure, distributions and motions of stars, gas, and dust complexes in NGC 4314 shows good agreement. The model predicts the velocity fields observed in this galaxy.
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Nishida, M. T., and K. Wakamatsu. "Bar Destruction Mechanism by External Interactions." International Astronomical Union Colloquium 157 (1996): 366–68. http://dx.doi.org/10.1017/s025292110005003x.
Texte intégralRésumé :
AbstractTo investigate bar destruction by a vertical head-on galaxy encounter, the dynamical evolution after the instantaneous momentum change of the impulsive approximation of a vertical head-on galaxy encounter, and the instability of finite amplitude one-armed perturbations to barred structure, are investigated by 2-dimensional N-body simulations.Preliminary results show that off-center vertical head-on collisions induce bar destruction but collisions in which the colliding galaxy passes through the very center of the target galaxy do not induce bar destruction.
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Papaderos, P. "Photometric Structure and Star Formation in Blue Compact Dwarf Galaxies." Proceedings of the International Astronomical Union 2, S235 (2006): 327. http://dx.doi.org/10.1017/s1743921306006922.
Texte intégralRésumé :
The star-formation history and chemodynamical evolution of Blue Compact Dwarf (BCD) galaxies are central issues in dwarf galaxy research. In spite of being old in their vast majority, BCDs resemble in many aspects unevolved low-mass galaxies in the early universe. They are gas-rich (Hi mass fraction of typically > 30%) and metal-deficient (7.1 $\la$ 12+log(O/H) $\la$ 8.3) extragalactic systems, undergoing intense star-forming (SF) activity within an underlying low-surface brightness (LSB) host galaxy.
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Bobylev, V. V., and A. T. Bajkova. "Study of the structure and kinematics of the Galaxy based on data on classical Cepheids." Publications of the Pulkovo Observatory 228 (May 2023): 1–25. http://dx.doi.org/10.31725/0367-7966-2023-228-2.
Texte intégralRésumé :
Classical Cepheids are important for studying the properties of the galactic disk, the spiral structure of the Galaxy, its rotation, evolution, etc. This article provides an overview of the main results of studying the structure and kinematics of the Galaxy, which were obtained by various scientific teams using classical Cepheids. The main attention is paid to the results of studying the Galaxy obtained by the authors of this work. The following issues are considered: a) the nature of the spatial distribution of Cepheids in the Galaxy, both near the equatorial plane of the Galaxy and in the vertical direction; in particular, the relationship of Cepheids with the large-scale Warp of the galactic disk is considered; b) the use of young Cepheids to refine the parameters of the spiral pattern of the Galaxy; c) the use of young Cepheids to refine the rotation parameters Galaxies and perturbation velocities caused by the influence of the galactic spiral density wave.
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Haud, U., M. Jôeveer, and J. Einasto. "A model of our Galaxy." Symposium - International Astronomical Union 106 (1985): 85–94. http://dx.doi.org/10.1017/s0074180900242113.
Texte intégralRésumé :
The construction of models is the most effective tool for a synthesis of various observational data and for a quantitative study of physical and dynamical structure and evolution of stellar systems. Classical models of spiral galaxies were based on rotational velocities, which were identified with circular velocities. They were designed to represent the galactic attraction force in the radial direction.
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O'Hely, Eileen, Warrick J. Couch, Ian Smail, Alastair C. Edge, and Ann Zabludoff. "The Las Campanas/AAT Rich Cluster Survey." Publications of the Astronomical Society of Australia 15, no. 3 (1998): 273–79. http://dx.doi.org/10.1071/as98273.
Texte intégralRésumé :
AbstractSome unsolved cosmological questions remain in relation to the formation of structure in the universe. One way of addressing such questions is to use rich galaxy clusters as tracers of the growth of large-scale structure. To date, studies of rich clusters of galaxies have concentrated on systems generally at either high redshift or in the local universe. The properties of clusters and their constituent galaxies at these extrema are becoming well understood. In particular, it is becoming clear that rich clusters have undergone considerable evolution both dynamically and in their galaxy populations over the last 5–8 Gyr. We are undertaking a detailed study of rich clusters of galaxies in the range 0·05 ≲ z ≲ 0·15. Our results will be directly comparable to those of previous studies both at high and low redshift and, for the first time, provide continuous coverage across this important and unexplored transitory epoch in terms of galaxy evolution and structure growth.
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Boulanger, François. "Structure and evolution of the Milky Way: the interstellar medium perspective." Proceedings of the International Astronomical Union 5, H15 (2009): 182–83. http://dx.doi.org/10.1017/s1743921310008628.
Texte intégralRésumé :
AbstractThe Herschel and Planck satellites have started imaging the sky at far-IR to mm wavelengths with an unprecedented combination of sky and spectral coverage, angular resolution, and sensitivity, thus opening the last window of the electromagnetic spectrum on the Galaxy. Dedicated observing programs on Herschel and the Planck all-sky survey will provide the first complete view at cold dust across the Galaxy, opening new perspectives on the structure and dynamical evolution of the Milky Way relevant to Gaia. The analysis and modelling of these observations will contribute to our understanding of two key questions: how do stars form from interstellar matter? how are the interstellar medium and the magnetic field dynamically coupled? The comparison with Gaia observations will contribute to build a 3D model of the Galactic extinction taking into account dust evolution between ISM components
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Murakami, I., and A. Babul. "Evolution of Dwarf Galaxies in High Pressure Environments." Symposium - International Astronomical Union 186 (1999): 483. http://dx.doi.org/10.1017/s0074180900113476.
Texte intégralRésumé :
We use 2D hydrodynamical calculations to examine the effect of the external medium on evolution of supernova-driven outflows from dwarf galaxies. Babul & Rees (1992) have suggested a high external pressure may be able to prevent the outflows from escaping beyond the galaxy and that this material, as it cools and falls back into the galaxy, would serve as fuel for a second epoch of star formation. When thermal pressure is dominant, such evolution of the outflows is seen in our simulations and the gas falls back into the galaxy. Babul & Rees, however, did not take into account the possibility that in high pressure environments such as clusters, galaxies are moving and therefore, subject to ram pressure. In our simulations, we find that ram pressure causes the mass shell associated with the outflow to fragment into clumps. These clumps remain in the vicinity of the galaxy for a few tens of million years before being swept away. The distribution of the clouds gives the galaxy in our simulations a characteristic “head-tail” appearance. If the clouds experience star formation during this epoch, we would expect that the light distribution would also show this “head-tail” feature. The tail-like structure is a transient feature that will eventually disappear. We speculate that galaxies observed by Dickinson (1996) in the z = 1.15 cluster around 3C324 are such galaxies.
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Eskridge, P. B. "Dwarf Spheroidal Galaxies." Symposium - International Astronomical Union 161 (1994): 525–33. http://dx.doi.org/10.1017/s0074180900048026.
Texte intégralRésumé :
Dwarf Spheroidal (dSph) galaxies are the faintest baryonic systems recognized as galaxies. Understanding the structure and stellar populations of these systems is critical for the modelling of their formation and evolution, and by extension, for understanding the general problem of galaxy formation and evolution. Further, as dSphs are the only available probes of the distant halo of the Galaxy, understanding their structure is a crucial step in the study of the gravitational potential of the halo and the mass of the Galaxy. I will not attempt to review fully all current topics of dSph research. Instead, I will concentrate specifically on those issues that are directly related (as I see it) to the overall topic of wide-field imaging. Recent reviews covering other aspects of dSph research have been written by DaCosta (1988, 1992) and Pryor (1992).
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Kormendy, John. "Internal secular evolution in disk galaxies: the growth of pseudobulges." Proceedings of the International Astronomical Union 3, S245 (2007): 107–12. http://dx.doi.org/10.1017/s1743921308017407.
Texte intégralRésumé :
AbstractObservational and theoretical evidence that internal, slow (“secular”) evolution reshapes galaxy disks is reviewed in Kormendy & Kennicutt (2004). This update has three aims. First, I emphasize that this evolution is very general – it is as fundamental to the evolution of galaxy disks as (e. g.) core collapse is to globular clusters, as the production of hot Jupiters is to the evolution of protoplanetary disks, and as evolution to red giants containing proto-white-dwarfs is to stellar evolution. One consequence for disk galaxies is the buildup of dense central components that get mistaken for classical (i. e., merger-built) bulges but that were grown out of disk stars and gas. We call these pseudobulges. Second, I review new results on pseudobulge star formation and structure and on the distinction between boxy and disky pseudobulges. Finally, I highlight how these results make a galaxy formation problem more acute. How can hierarchical clustering produce so many pure disk galaxies with no evidence for merger-built bulges?
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Poezd, A., A. Shukurov, and D. D. Sokoloff. "Nonlinear Dynamo in a Disk Galaxy." Symposium - International Astronomical Union 157 (1993): 349–53. http://dx.doi.org/10.1017/s0074180900174406.
Texte intégralRésumé :
A nonlinear thin-disk galactic dynamo model based on α-quenching is proposed. Assuming that the mean helicity depends on the magnetic field strength averaged across the disk, we derive a universal form of nonlinearity in the radial dynamo equation. We discuss the evolution of the regular magnetic field in the Milky Way and the Andromeda Nebula. It is argued that the reversals of the regular magnetic field in the Galaxy are a relic inherited from the structure of the seed field. We also briefly discuss the role of the turbulent diamagnetism and the effects of galactic evolution on the dynamo.
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Tolasa, Diriba. "The Interplay Between Supermassive Black Holes and Their Host Galaxies: A Multi-wavelength Approach." International Journal of Astrophysics and Space Science 13, no. 2 (2025): 36–48. https://doi.org/10.11648/j.ijass.20251302.12.
Texte intégralRésumé :
The interplay between supermassive black holes (SMBHs) and their host galaxies is a critical area of research in extragalactic astronomy, shedding light on the fundamental processes that govern galaxy formation and evolution. This study employs a multi-wavelength approach to investigate the correlation between SMBHs and their host galaxies, utilizing data from radio, optical, infrared, and X-ray observations. Recent advancements in observational technologies have enabled deeper insights into the mechanisms at play in this complex relationship. We begin by examining the fundamental connection between the mass of SMBHs and various properties of their host galaxies, such as stellar mass, bulge structure, and star formation rate. Our analysis reveals a significant correlation between SMBH mass and the central velocity dispersion of stars, consistent with the established M-sigma relation. However, deviations from this correlation suggest the influence of additional factors, such as environmental conditions and galaxy mergers. Furthermore, we explore the feedback mechanisms initiated by SMBHs, particularly through active galactic nuclei (AGN) activity. Multi-wavelength observations allow us to assess the impact of AGN feedback on star formation within host galaxies. We document cases where AGN activity suppresses star formation, resulting in a transition from star-forming to passive galaxies. Conversely, we also identify scenarios where SMBH feedback may trigger star formation, underscoring the dual role of SMBHs in galaxy evolution. In addition to examining individual cases, we utilize large galaxy survey data sets to analyze trends across different galaxy populations. Our findings indicate variations in SMBH-host galaxy relationships based on galaxy morphology and environment, suggesting that the evolution of both components is influenced by cosmic structures. This study highlights the importance of a multi-wavelength approach in understanding the complex dynamics between SMBHs and their host galaxies. By integrating diverse data sources, we provide a comprehensive view of how these colossal entities coexist and interact. Our results contribute to the broader discourse on galaxy formation theories and the role of SMBHs in shaping the universe, paving the way for future investigations that will deepen our understanding of cosmic evolution.
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Nasello, G., A. C. Robin, C. Reylé, and N. Lagarde. "Study of the thick disc of the Milky Way from a population synthesis model." Proceedings of the International Astronomical Union 13, S334 (2017): 347–48. http://dx.doi.org/10.1017/s1743921317006846.
Texte intégralRésumé :
AbstractThe thick disc is a major component of the Milky Way but its epoch of formation and characteristics are still not yet well constrained. The Besançon Galaxy Model (BGM, Robin et al. 2003) is a population synthesis model based on a scenario of formation and evolution of the Galaxy, a star formation history, and a set of stellar evolution models. Thanks to Lagarde et al. (2017), new evolutionary tracks have been introduced into the Besancon Galaxy Model (STAREVOL, Lagarde et al. 2012) to provide global asteroseismic and surface chemical properties along the evolutionary stages. This updated Galaxy model will allow us to constrain the thick disc structure and history using the Markov Chain Monte Carlo fitting method (MCMC). We show preliminary results applying this MCMC method on the 2MASS photometric survey.
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Doi, Akihiro, Motoki Kino, Nozomu Kawakatu, and Kazuhiro Hada. "The radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342 in a galaxy merger." Monthly Notices of the Royal Astronomical Society 496, no. 2 (2020): 1757–65. http://dx.doi.org/10.1093/mnras/staa1525.
Texte intégralRésumé :
ABSTRACT The supermassive black holes (SMBHs) of narrow-line Seyfert 1 galaxies (NLS1s) are at the lower end of the mass function of active galactic nuclei (AGNs) and reside preferentially in late-type host galaxies with pseudobulges, which are thought to be formed by internal secular evolution. On the other hand, the population of radio-loud NLS1s presents a challenge for the relativistic jet paradigm, which states that powerful radio jets are associated exclusively with very high mass SMBHs in elliptical hosts, which are built up through galaxy mergers. We investigated distorted radio structures associated with the nearest gamma-ray-emitting, radio-loud NLS1, 1H 0323+342. This provides supporting evidence for the merger hypothesis based on past optical/near-infrared observations of its host galaxy. The anomalous radio morphology consists of two different structures: the inner curved structure of the currently active jet and an outer linear structure of low-brightness relics. Such coexistence might be indicative of the stage of an established black hole binary with precession before the black holes coalesce in the galaxy merger process. 1H 0323+342 and other radio-loud NLS1s under galaxy interactions may be extreme objects on the evolutionary path from radio-quiet NLS1s to normal Seyfert galaxies with larger SMBHs in classical bulges through mergers and merger-induced jet phases.