210 research outputs found
Dynamical masses and non-homology of massive elliptical galaxies grown by dry mergers
We study whether dry merger-driven size growth of massive elliptical galaxies
depends on their initial structural concentration, and analyse the validity of
the homology hypothesis for virial mass determination in massive ellipticals
grown by dry mergers. High-resolution simulations of a few realistic merger
trees, starting with compact progenitors of different structural concentrations
(S\'ersic indices n), show that galaxy growth has little dependence on the
initial S\'ersic index (larger n leads to slightly larger size growth), and
depends more on other particulars of the merger history. We show that the
deposition of accreted matter in the outer parts leads to a systematic and
predictable breaking of the homology between remnants and progenitors, which we
characterize through the evolution, during the course of the merger history, of
virial coefficients K = GM/Re \sigma^2 associated to the most commonly-used
dynamical and stellar mass parameters. The virial coefficient for the luminous
mass, K , is about 50 per cent larger at the z = 2 start of the merger
evolution than in z = 0 remnants. Ignoring virial evolution leads to biased
virial mass estimates. We provide K corresponding to a variety of dynamical and
stellar mass parameters, and provide recipes for the dynamical determination of
galaxy masses. For massive, non-compact ellipticals, the popular expression M =
5 Re \sigma^2 / G underestimates the dynamical mass within the luminous body by
factors of up to 4; it instead provides an approximation to the total stellar
mass with smaller uncertainty than current stellar population models
Spheroid and disk signatures in galaxy bulges
Recent progress on the structure and dynamics of bulges is reviewed. Those
aspects that link galaxy bulges either to oblate spheroids akin to elliptical
galaxies or to rapidly-rotating, flattened systems more nearly resembling the
products of disk internal transformations, are highlighted. The analysis of
surface brightness profiles derived from HST data is reviewed to show that
unresolved nuclear components detected by HST have biased the determination of
surface brightness profiles obtained from the ground; r^1/4 profiles are
virtually nonexistent in galaxy bulges. Predictions from accretion N-body
models on the shape of surface brightness profiles are discussed. The position
of bulges on the Fundamental Plane of elliptical galaxies is examined to infer
clues on bulge population ages and bulge dynamical structure. Kinematic
diagnostics on the internal dynamics of bulges are examined. Finally, a new
approach to the kinematic analysis of galaxies, based on the use of synthetic
spectra of single stellar population models instead of the standard stellar
templates, is presented.Comment: Review at JENAM2002 Galaxy Dynamics Workshop (Porto, Portugal, 2002
September 3-7). 12 pages, 4 figures, includes EAS style fil
Building an architecture of everyday life in South Korea: mass housing estates in Seoul as an instrument of modernization, 1962-2008
The mass housing estates – apat’u tanji in Korean – that were developed in Seoul during the second half of the twentieth century are the most characteristic spatial practice of the South Korean modernization project. They are not just a passive outcome of economic and urbanization processes, but an active political means of introducing new economic and social structures within the modernizing project of the developmental regime, with a radical impact on the transformation of the city and society. Thus, they function at two interrelated levels: as the building blocks of a modern project of city-making in physical terms (an urbanizing mechanism), and as a means of constructing a modern urban society and way of life (a socializing mechanism).
Mass housing estates have been instrumental in shaping all the settings of everyday life, from the urban scale to residential neighborhoods and domestic habitats.
Although an estimated 53% of the population of Seoul lives in mass housing estates, they are not considered a disciplinary subject. They are largely disregarded as banal by the architectural community and often criticized from a sociological, economic or policy perspective. This research questions that assumed banality and inquiries into the spatial and organizational logics behind the apparent normality of these estates.
The thesis approaches them as an architectural topic and proposes a methodology to identify, describe, interpret and criticize them from a disciplinary stance at different scales: the scale of the city, the scale of the housing estate and the scale of the building type or residential unit. These three scales determine the basic structure of the research.
The findings demonstrate that the implementation of mass housing in Seoul has not been a homogeneous process. Instead, it has followed different rationales over the study period. The housing problem was understood at urban scale simply as the quantitative provision of housing units. The complexes did not contribute to the formation and organization of urban space and remained as isolated fragments that are partially coordinated with other processes of urban growth, the existing city and the natural context. Nevertheless, the systematization of planning processes and formal models for the provision of housing units at a massive scale were consolidated into a technology that normalized the construction of entire urban fragments.
At the scale of the housing estate, relevant innovations were produced for a brief period with the introduction of site planning strategies based on residential clusters. The development of a standardized unit type also yielded an innovative modern layout which hybridizes global housing models with local understanding of domesticity, privacy, posture and comfort.
The thesis evidences how, ultimately, the shift to private development at the end of the 1980s prevented further development of the mass housing model. Today, apat’u tanji have become spatial organizational protocols that standardize the built environment at different scales. Site planning strategies and unit types developed earlier under the patronage of the public housing authority were captured by the market and pressed into service without their original community-building agendas or theoretical bases.Els polĂgons residencials -o apat’u tanji en coreĂ - construĂŻts a SeĂĽl durant la segona meitat del segle XX sĂłn la prĂ ctica espacial mĂ©s caracterĂstica del projecte modernitzador de Corea del Sud. No sĂłn nomĂ©s el subproducte passiu de processos econòmics i urbanitzadors, sinĂł una estratègia polĂtica activa amb l’objectiu d'introduir noves estructures econòmiques i socials dins del projecte modernitzador del règim desenvolupamentalista, i han tingut un impacte radical en la transformaciĂł de la ciutat i la societat. AixĂ, operen a dos nivells interrelacionats: com a pilars del projecte modern de fer ciutat en termes fĂsics (un mecanisme d’urbanitzaciĂł), i com a mitjĂ per a donar forma a una societat i un estil de vida urbans moderns (un mecanisme de socialitzaciĂł). Els polĂgons d'habitatge massiu han estat essencials per definir diferents Ă mbits de la vida quotidiana, des de l’escala urbana, passant per l’escala dels barris residencials, fins els hĂ bitats domèstics. Malgrat que es calcula que un 53% de la poblaciĂł de SeĂĽl viu en polĂgons residencials, no sĂłn considerats com un tema disciplinar per la comunitat arquitectònica. SĂłn menystinguts per la seva percebuda banalitat i estudiats majoritĂ riament des d’una perspectiva sociològica, econòmica o polĂtica. La recerca posa en dubte aquesta suposada banalitat i s’interessa per les lògiques espacials i organitzatives ocultes darrere l’aparent normalitat dels polĂgons d’habitatge massiu. La tesi els aborda com un tema arquitectònic i proposa una metodologia per identificar-los, descriure’ls, interpretar-los i criticar-los des de la disciplina a diferents escales: a l'escala de la ciutat; a l'escala de la parcel·la; i a l’escala del tipus edificatori-unitat residencial. Aquests tres Ă mbits determinen l’estructura bĂ sica de la investigaciĂł. Els resultats de la recerca demostren que l’adopciĂł de polĂgons d’habitatge massiu per respondre a la manca crònica d’habitatge durant gran part del segle XX no ha estat un procĂ©s homogeni. Els polĂgons han adoptat una varietat de papers urbans, s’han destinat a diversos pĂşblics i han seguit diferents lògiques de posicionament dins la ciutat durant el perĂode d’estudi. El problema de l’habitatge va ser entès a escala urbana simplement com la provisiĂł quantitativa d’unitats residencials, de manera que els polĂgons no han contribuĂŻt a la formaciĂł i l’OrganitzaciĂł de l'espai urbĂ . Han romĂ s com a fragments urbans aĂŻllats, nomĂ©s integrats de forma parcial amb altres processos de creixement urbĂ , amb la ciutat existent i amb el context natural. No obstant, la sistematitzaciĂł de processos de planificaciĂł i de models formals per a la provisiĂł d'unitats d’habitatge a gran escala es va consolidar en una tecnologia que va normalitzar la construcciĂł unitĂ ria de fragments urbans sencers. A l’escala del planejament dels polĂgons es van produir innovacions rellevants durant un breu perĂode amb la introducciĂł d'estratègies d'ordenaciĂł basades en clĂşsters d’edificis residencials. El desenvolupament d’una unitat residencial estandarditzada tambĂ© va donar lloc a una tipologia moderna i innovadora que hibrida models d’habitatge globals amb formes autòctones d'entendre la domesticitat, la comoditat, l’ús del pla del sòl i la privacitat. La tesi evidencia com la transiciĂł vers el desenvolupament privat a finals dels anys vuitanta va torbar l’evoluciĂł del model d’habitatge massiu a Corea del Sud. Avui dia, els apat’u tanji han esdevingut protocols d’organitzaciĂł espacial que estandarditzen l’entorn construĂŻt a diferents escales. Els sistemes d’ordenaciĂł i les tipologies residencials desenvolupats anteriorment sota la direcciĂł de l’administraciĂł pĂşblica van ser apropiats pel mercat sense tenir en compte els objectius socials i els continguts teòrics originals.Postprint (published version
Aixecament grĂ fic, diagnosi i proposta d'intervenciĂł per l'edifici del carrer Manresa 36 de Calders
Concurs als millors Projectes Fi de Carrera d'Arquitectura Tècnica i Treballs Fi de Grau de Ciències i Tecnologies de l'Edificació defensats durant el curs acadèmic 2016/17.El present treball final de grau es du a terme en l’edifici situat al Carrer Manresa 36, del poble de
Calders, anomenat “Cal Tarrés”.
Cal Tarrés és una casa de poble als quatre vents de dimensions més grans que la resta de cases
del seu entorn tot assemblant-se a una petita masia, que es troba construïda sobre una parcel·la de
1.297 m2. La seva part primitiva data de mitjans del segle XVII, i la part més actual de finals del segle
XIX.
Degut a la singularitat de la casa i a que actualment es troba deshabitada i en un estat força precari
en el seu conjunt, he cregut que seria una bona opciĂł desenvolupar en ella el meu treball final de
grau. Considero que això pot ser molt beneficiĂłs per al seu futur ja que, en el treball, s’hi realitzarĂ
una proposta d’intervenció que descriurà les accions necessà ries que s’han de dur a terme per tal
que torni a entrar en servei d’una forma satisfactòria, tot resolent les deficiències detectades i donantli
un nou ús en el que es convertirà en una residència per a la gent gran adaptada als està ndards i
normatives exigibles en aquest tipus d’ús i edificació.
També serà una gran oportunitat personal de posar en prà ctica els coneixements adquirits durant el
transcurs dels meus estudis i a part, assimilar nous coneixements i mètodes de treball obtinguts
durant la seva realitzaciĂł.
Per tal de poder dur-lo a terme i complir amb tots els objectius marcats, primerament es realitzarĂ
un aixecament grà fic detallat de l’estat actual de l’edificació. Això permetrà veure i entendre d’una
forma clara els sistemes constructius que el composen i el seu funcionament.
A la vegada que es realitzi l’aixecament grà fic es farà una recerca històrica, tot buscant possible
documentaciĂł antiga i informaciĂł existent que hi hagi disponible com Ă©s es el cas de llibres,
fotografies, plà nols antics, entrevistes a gent del poble i als antics propietaris, etc. D’aquesta manera
es podran veure les modificacions que ha anat patint al llarg de la seva història i entendre els
sistemes constructius emprats en cada època tot comprenent quina era la seva finalitat i podent aixĂ
crear una proposta d’intervenció respectuosa amb l’edifici i el seu entorn.
Seguidament es realitzarà una diagnosi, per tal de veure les possibles lesions que té, comprendre
l’estat en que es troba i poder decidir posteriorment el tipus d’intervenció necessà ria a dur a terme.
Finalment es realitzarà la proposta d’intervenció que marcarà les pautes per donar un nou ús al
edifici, reconvertint-lo d’habitatge a residència per a gent gran. En aquest apartat s’estudiaran les
necessitats i els espais dels que haurĂ de disposar per tal de complir amb la funcionalitat requerida
pel nou ús i s’estudiaran i modificaran els elements estructurals que siguin necessaris, dintre de les
possibilitats, perquè compleixi amb les noves exigències desitjades i amb la normativa vigent.Award-winnin
The Prosecution Service Function within the Spanish Criminal Justice System
The national criminal justice system of Spain is described. Special attention is paid to the function of the Public Prosecution Services within this framework and its relationship to police and courts. The article not only refers to legal provisions but to the factual handling of criminal cases as wel
Creation and Business Plan of the project UniRealidad
Treballs Finals del Grau de d'AdministraciĂł i DirecciĂł d'Empreses, Facultat d'Economia i Empresa, Universitat de Barcelona, Curs: 2017-2018 , Tutor: Yuliya Kasperskaya(eng) This essay includes the Business Plan for the non-profit association UniRealidad.
UniRealidad is a project, which aims to improve the transparency and information access within
the educational sector. The project describes the new audiovisual platform of getting informed
about educational opportunities. It is differentiated from the existing approaches by goodquality
and user-friendly service.(cat) Aquest assaig inclou el Pla d'empresa per a l'associaciĂł sense Ă nim de lucre UniRealidad.
UniRealidad és un projecte que té com a objectiu millorar l'accés a la transparència i la
informaciĂł dins del sector educatiu. El projecte descriu la nova plataforma audiovisual per
informar-se sobre les oportunitats educatives. Es diferencia dels enfocaments existents per
un servei de bona qualitat i fĂ cil d'utilitzar
The Formation of Galactic Bulges
We summarise some recent results about nearby galactic bulges that are
relevant to their formation. We highlight a number of significant advances in
our understanding of the surface brightness profiles, stellar populations, and
especially the very centers of spiral galaxies. We also view our own Milky Way
as if it were an external galaxy. Our main conclusions are that bulges of
early-type spirals (S0 -- Sb) contain central nuclear components, just like
late-type spirals and most other types of galaxies. The luminosities of these
central components correlate best with total bulge luminosity, and not as well
with morphological type. Bulges of early-type spiral galaxies follow the
fundamental plane and the colour/line strength vs. luminosity relations of
elliptical galaxies. Although we have a reasonable idea about bulges of
early-type spirals we know much less about late-type bulges. However, the close
resemblance of our Milky Way Bulge to bulges in external disk galaxies makes us
suspect that bulges of late-type spirals might be very similar as well.Comment: 10 pages, invited review presented at 'Baryons in Dark Matter',
Novigrad Oct 5-9, 2004; eds. R. Dettmar, U. Klein and P. Salucci. On-line
publication at http://pos.sissa.i
Formation of kinematic subsystems in stellar spiral-spiral mergers
[EN]We show that kinematically peculiar cores may be generated in stellar spiral-spiral mergers. Kinematic segregation appears as the central bulges transport orbital angular momentum inward to the center of the remnant, while the outer parts keep the spin signature of the precursor disks. The peculiar core is composed mostly of bulge material, and its size best matches that of observed peculiar cores for mergers with unequal galaxy masses (~2:1). Population decoupling is predicted by the rapid radial decrease of the bulge fraction in the remnant. In this scenario, a starburst may pump up the remnant metallicity, but otherwise the high metallicity of the kinematically decoupled core is built on the high metal content of the inner bulges rather than on a high selfenrichment of a population built from scratch out of the precursors’ gas. Mergers with galaxy mass ratios 3:1 and above generate disk galaxies with counterrotating bulges.Peer reviewe
NGC1277: a massive compact relic galaxy in the nearby Universe
As early as 10 Gyr ago, galaxies with more than 10^11 Msun in stars already
existed. While most of these massive galaxies must have subsequently
transformed through on-going star formation and mergers with other galaxies, a
small fraction (<0.1%) may have survived untouched till today. Searches for
such relic galaxies, useful windows to explore the early Universe, have been
inconclusive to date: galaxies with masses and sizes like those observed at
high redshift (M*>10^11 Msun; Re<1.5 kpc) have been found in the local
Universe, but their stars are far too young for the galaxy to be a relic
galaxy. This paper explores the first case of a nearby galaxy, NGC1277 (in the
Perseus cluster at a distance of 73 Mpc), which fulfills all the criteria to be
considered a relic galaxy. Using deep optical spectroscopy, we derive the star
formation history along the structure of the galaxy: the stellar populations
are uniformly old (>10 Gyr) with no evidence for more recent star formation
episodes. The metallicity of their stars is super-solar ([Fe/H]=0.20+-0.04) and
alpha enriched ([alpha/Fe]=0.4+-0.1). This suggests a very short formation time
scale for the bulk of stars of this galaxy. This object also rotates very fast
(Vrot~300 km/s) and has a large velocity dispersion (sigma>300 km/s). NGC1277
will allow future explorations in full detail of properties such as the
structure, internal dynamics, metallicity, dust content and initial mass
function at around 10-12 Gyr back in time when the first massive galaxies were
built.Comment: 4 figures; Accepted for publication at ApJ Letter
- …