1. "Peaks" and Low Surface Brightness Galaxies - Low Surface,Brightness Galaxies,John Hultman
. It has been proposed that low surface brightness (LSB) galaxies may form in low density regions as a result of certain statistical properties of the density field (Hoffman et al. 1992). This idea is investigated with direct Hydrodynamical simulations, using a combined Smooth Particle Hydrodynamics (SPH) and gravitational tree method. It is found that although more mass is collected around a density peak in a void region, compared to a peak of equal height in region of average background density, the resulting galactic disk is not of LSB type. Key words: numerical methods -- hydrodynamics -- galaxies - formation -- galaxies - low surface brightness galaxies - structure 1. Introduction There has been...

2. Isolated elliptical galaxies - Reda, Fatma M.
This thesis presents a detailed study of a well defined sample of isolated early-type galaxies. We define a sample of 36 nearby isolated early-type galaxies using a strict isolation criteria. New wide-field optical imaging of 20 isolated galaxies confirms their early-type morphology and relative isolation. We find that the isolated galaxies reveal a colour-magnitude relation similar to cluster ellipticals, which suggests that they formed at a similar epoch to cluster galaxies, such that the bulk of their stars are very old. However, several galaxies of our sample reveal evidence for dust lanes, plumes, shells, boxy and disk isophotes. Thus at...

3. Isolated elliptical galaxies - Reda, Fatma M.
This thesis presents a detailed study of a well defined sample of isolated early-type galaxies. We define a sample of 36 nearby isolated early-type galaxies using a strict isolation criteria. New wide-field optical imaging of 20 isolated galaxies confirms their early-type morphology and relative isolation. We find that the isolated galaxies reveal a colour-magnitude relation similar to cluster ellipticals, which suggests that they formed at a similar epoch to cluster galaxies, such that the bulk of their stars are very old. However, several galaxies of our sample reveal evidence for dust lanes, plumes, shells, boxy and disk isophotes. Thus at...

4. MgII absorption through intermediate redshift galaxies - Churchill, Christopher W.; Kacprzak, Glenn G.; Steidel, Charles C.
The current status and remaining questions of Mgii absorbers are reviewed with an eye toward new results incorporating high quality Hubble Space Telescope images of the absorbing galaxies. In the end, we find that our current picture of extended gaseous regions around galaxies at earlier epochs is in need of some revision; Mgii absorbing “halos” appear to be patchier and their geometry less regular than previously inferred. We also find that the so-called “weak” Mgii absorbers are associated with normal galaxies over a wide range of impact parameters, suggesting that this class of absorber does not strictly select low surface...

5. MgII absorption through intermediate redshift galaxies - Churchill, Christopher W.; Kacprzak, Glenn G.; Steidel, Charles C.
The current status and remaining questions of Mgii absorbers are reviewed with an eye toward new results incorporating high quality Hubble Space Telescope images of the absorbing galaxies. In the end, we find that our current picture of extended gaseous regions around galaxies at earlier epochs is in need of some revision; Mgii absorbing “halos” appear to be patchier and their geometry less regular than previously inferred. We also find that the so-called “weak” Mgii absorbers are associated with normal galaxies over a wide range of impact parameters, suggesting that this class of absorber does not strictly select low surface...

6. HST MID-UV IMAGING OF NEARBY GALAXIES - Rogier A. Windhorst; Violet A. Taylor; Rolf A. Jansen
Abstract We summarize Hubble Space Telescope projects that imaged a significant sample of nearby galaxies of all types and inclinations in the mid-UV with WFPC2 and some in the near-IR with NICMOS. The sample emphasizes high-surface brightness late-type, irregular, peculiar and merging galaxies, since these objects are the most prevalent at high redshifts. The sample is used to establish a local benchmark for quantitative classifications of galaxies seen by HST in their rest-frame UV, and in the next decade also by the James Webb Space Telescope. We review how nearby galaxies change their rest-frame structure and morphology from the rest-frame...

7. ON THE EXTENDED KNOTTED DISKS OF GALAXIES - Christlein, Daniel; Zaritsky, Dennis
The stellar disks of many spiral galaxies are twice as large as generally thought. We use archival data from the Galaxy Evolution Explorer mission to quantify the statistical properties of young stellar clusters in the outer, extended disks of a sample of 11 nearby galaxies. We find an excess of sources between 1.25 and 2 optical radii, R25, for five of the galaxies, which statistically implies that at least a quarter of such galaxies have this cluster population (90% confidence level), and no significant statistical excess in the sample as a whole beyond 2R25, even though one galaxy (M83) individually shows such an excess. Although...

8. High Resolution Imaging of Faint Blue Galaxies - Colless, Matthew; Schade, David; Broadhurst, T.J.; Ellis, R.S.
We have used HRCam on the CFHT to obtaIn subarcsec images of 26 galaxies with z = 0.1-0.7 from the redshift survey of Colless et al. The 17 galaxies of the primary sample have enhanced star formation indicated by [O II] equivalent widths greater than 20 A, while the nine galaxies of the comparison sample have equivalent widths of less than 10 A. By fitting exponential discs or r^1/4^ bulges to B, V and I images, we derive scalelengths for the blue and red stellar populations and so establish the location of the star formation (in the nucleus or the...

9. High Resolution Imaging of Faint Blue Galaxies - Colless, Matthew; Schade, David; Broadhurst, T.J.; Ellis, R.S.
We have used HRCam on the CFHT to obtaIn subarcsec images of 26 galaxies with z = 0.1-0.7 from the redshift survey of Colless et al. The 17 galaxies of the primary sample have enhanced star formation indicated by [O II] equivalent widths greater than 20 A, while the nine galaxies of the comparison sample have equivalent widths of less than 10 A. By fitting exponential discs or r^1/4^ bulges to B, V and I images, we derive scalelengths for the blue and red stellar populations and so establish the location of the star formation (in the nucleus or the...

10. Mg II absorbing galaxies: morphologies and kinematics - Churchill, Christopher W.; Steidel, Charles C.; Kacprzak, Glenn G.
In this contribution, we review our current knowledge of the properties of galaxies, and their extended halos, selected by Mg II absorption in the spectra of background quasars. We then describe recent efforts to quantify the morphologies and orientations of galaxies and explore how these relate to the gas kinematics. In a sample of 26 galaxies, we find no clear connection between the orientation of the quasar line of sight through the galaxy and the velocity spread of the gas. However, it appears that the quantity of gas "stirred up" in the halo may be correlated to asymmetry in the...

11. Mg II absorbing galaxies: morphologies and kinematics - Churchill, Christopher W.; Steidel, Charles C.; Kacprzak, Glenn G.
In this contribution, we review our current knowledge of the properties of galaxies, and their extended halos, selected by Mg II absorption in the spectra of background quasars. We then describe recent efforts to quantify the morphologies and orientations of galaxies and explore how these relate to the gas kinematics. In a sample of 26 galaxies, we find no clear connection between the orientation of the quasar line of sight through the galaxy and the velocity spread of the gas. However, it appears that the quantity of gas "stirred up" in the halo may be correlated to asymmetry in the...

12. The nuclei of nearby giant elliptical galaxies - Seigar, Marc S.; Lynam, P. D.; Graham, Alister W.; Bodnarik, J. G.
We have observed 26 giant elliptical galaxies in the near-infrared K-band with UFTI on UKIRT. These were observed in excellent seeing conditions (~0.3 arcsec) and one of the galaxies revealed a triple nucleus that had not been previously observed as such. Of the galaxies observed, 18 are coincident with the x-ray centers of their host clusters and 8 are not. We will present the results of investigations of their nuclear properties, such as their nuclear surface brightness profiles, the slope of the inner profile, and multiple nuclei.

13. The nuclei of nearby giant elliptical galaxies - Seigar, Marc S.; Lynam, P. D.; Graham, Alister W.; Bodnarik, J. G.
We have observed 26 giant elliptical galaxies in the near-infrared K-band with UFTI on UKIRT. These were observed in excellent seeing conditions (~0.3 arcsec) and one of the galaxies revealed a triple nucleus that had not been previously observed as such. Of the galaxies observed, 18 are coincident with the x-ray centers of their host clusters and 8 are not. We will present the results of investigations of their nuclear properties, such as their nuclear surface brightness profiles, the slope of the inner profile, and multiple nuclei.

14. Spatial Clustering of Galaxies in Large Datasets - Er S. Szalay; Department Of Physics; Tamás Budavari; Er S. Szalay A; Tamás Budavari A; Andrew Connolly B; Jim Gray C; Takahiko Matsubara D; Adrian Pope A; István Szapudi E
Datasets with tens of millions of galaxies present new challenges for the analysis of spatial clustering. We have built a framework that integrates a database of object catalogs, tools for creating masks of bad regions, and a fast (NlogN) correlation code. This system has enabled unprecedented efficiency in carrying out the analysis of galaxy clustering in the SDSS catalog. A similar approach is used to compute the three-dimensional spatial clustering of galaxies on very large scales. We describe our strategy to estimate the effect of photometric errors using a database. We discuss our efforts as an early example of data-intensive...

15. Spatial Clustering of Galaxies in Large Datasets - Er S. Szalay A; Tamás Budavari A; Andrew Connolly B; Jimgray C; Takahiko Matsubara D; Adrian Pope A; István Szapudi E
Datasets with tens of millions of galaxies present new challenges for the analysis of spatial clustering. We have built a framework, that integrates a database of object catalogs, tools for creating masks of bad regions, and a fast (NlogN) correlation code. This system has enabled unprecedented efficiency in carrying out the analysis of galaxy clustering in the SDSS catalog. A similar approach is used to compute the three-dimensional spatial clustering of galaxies on very large scales. We describe our strategy to estimate the effect of photometric errors using a database. We discuss our efforts as an early example of data-intensive...

16. A emissão das galáxias esferoidais no infravermelho médio - Ferrari, Fabricio
Propriedades fotométricas no infravermelho médio são apresentadas para uma amostra de 28 galáxias esferoidais, observadas em 6.75, 9.63 e 15 jlk com o instrumento ISOCAM a bordo do satélite ISO. As distribuições espectrais de energia (DEE) das galáxias foram derivadas usando dados do infravermelho médio junto com dados do UV, do ótico e do infravermelho próximo, previamente publicados. Estas DEE mostram duas componentes: a poeira quente aquecida até T ~ 260 K dominando a emissão no infravermelho médio e a população estelar com T ~ 4000 K, que domina no ótico. Da emissão no infravermelho médio pode ser visto que...

17. The effects of merging and environment on galaxies and clusters of galaxies - Owers, Matthew Scott, Physics, Faculty of Science, UNSW
This thesis addresses two fundamental questions in astrophysics: (i) To what extent is environment a driver of galaxy evolution? And (ii) How does hierarchical structure formation affect the galaxy environment? The former is addressed by examining the environments of starburst galaxies, the latter by examining clusters undergoing major mergers with focus placed on the efficacy of “cold fronts” in identifying systems that have recently undergone a major merger - an essential first step to understanding their impact. For the first of these studies, the 2dFGRS was exploited to select large samples of starburst galaxies. These were used to derive measurements...

18. Modelo da Galáxia utilizando contagens de estrelas no infravermelho - Priscilla Firmino Polido
A maioria dos primeiros modelos quantitativos para a estrutura da Galáxia utilizou o método de contagens de estrelas para explorar os parâmetros mais importantes da estrutura galáctica como um todo. Alguns dos mais importantes modelos devem-se a Bahcall & Soneira (1980), ao grupo de Besançon (Robin & Crezé, 1986), Wainscoat et al.(1992), Ortiz & Lépine (1993), entre outros. Os dados utilizados sofriam, no entanto, de incompletezas tanto em cobertura fotométrica quanto em cobertura espacial. Mesmo o levantamento IRAS, realizado nos anos 1980, cobrindo todo o céu em comprimentos de onda entre 12 e 100 µm, sofria de problemas de incompleteza...

19. Nebular Emission in X-ray Selected Brightest Cluster Galaxies - Samuele, Rocco
Optical spectra of Brightest Cluster Galaxies obtained from the X-ray selected cluster sample of the 160 Square Degree ROSAT survey are used to measure the equivalent widths of [OII]λ3727 and Hα nebular emission lines. This line emission is used to trace warm ionized gas in the interstellar media of 77 Brightest Cluster Galaxies, in clusters ranging in redshifts from z = 0.066-0.7 and X-ray Luminosities from LX = 0.04-4.27 × 10^44 erg s-1 [0.5-2 keV]. We find no[OII]λ3727 or Hα emission stronger than -15 Å or -5 Å respectively in any Brightest Cluster Galaxy. The frequency of detection of emission-line Brightest Cluster Galaxies of...

20. O contínuo e a região estendida de linhas estreitas das galáxias ativas ESO 362-G18 e ESO 362-G8 - Fraquelli, Henrique Aita
Foram analisados espectros óticos de fenda longa das galáxias Seyfert 1 ESO362-G18 e Seyfert 2 ESO362-G8. Estas duas galáxias apresentam emissão por gás de alta excitação em forma anisotrópica, possivelmente devido a colimação por um tóro de poeira. O objetivo do presente trabalho consiste em estudar o contínuo e a região estendida de linhas de emissão (ENLR) destes objetos. Este trabalho constitui-se no primeiro estudo detalhado realizado sobre estas galáxias. A população estelar em cada galáxia e caracterizada em função da distância ao núcleo. O contínuo nuclear e estudado em termos de duas componentes: a população estelar e a componente...

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