P.U. Catolica de Chile: Department of Astronomy and Astrophysics astro.puc.cl

1. P.U. Catolica de Chile: Department of Astronomy and Astrophysics www.astro.puc.cl

2. Research Areas: Extrasolar planets. Microlensing. Galactic structure. Open and Globular clusters. SN - Distance estimators Extragalactic globular clusters. Galaxy evolution and morphology. Elliptical galaxies. LSB, dwarf and star forming galaxies in relation to environment. High-z QSOs. Pairs, groups and clusters of galaxies. Stellar population in galaxies. Statistical properties of the galaxy distribution. Theoretical Astrophysics. Stellar interiors. Stellar structure. Neutron stars. Stellar evolution. Variable star phenomena.

3. Faculty Members: Dante Minniti (local Lenac coordinator). Optical-IR astronomy. Extrasolar planets. Galactic structure. Open and Globular clusters. Stellar populations and evolution. Variable star phenomena. Microlensing. Dwarf galaxies. Extragalactic globular clusters. Leopoldo Infante (Director). Galaxy and structure evolution. Pairs, groups and clusters of galaxies. LSB, dwarf and star forming galaxies in relation to environment. High-z QSOs. Felipe Barrientos.Galaxy evolution and morphology. Elliptical galaxies. Clusters of galaxies. Observational cosmology. Omar Benvenuto. Theoretical Astrophysics. Stellar interiors. Stellar structure. Márcio Catelan.Stellar evolution. Globular clusters. RR-Lyrae variable stars. Alejandro Clocchiatti. SN. Extensive studies of well observed bright events and usage of more distant events as distance estimators Gaspar Galaz.Stellar population in galaxies. Galaxy evolution. Statistical properties of the galaxy distribution. Hernán Quintana.Observational astrophysics. Clusters of galaxies. Interacting galaxies. Large scale structure. Andreas Reisenegger.Theoretical Astrophysics. Neutron stars. Clusters of galaxies. Structure formation. Cosmology.

4. Postdocs: Cécile Faure Gravitational lensing: strong and weak lensing. Galaxy groups and clusters. Quasars. Jura Borissova Resolved stellar populations, star clusters and associations. Variable stars in globular clusters and local group galaxies Nelson Padilla LSS, galaxy formation, cosmological parameters, CMB. Verónica Motta Quasars and quasar host galaxies. Dust extintion at high z. Andrew Drake Microlensing, MACHO search. Manuela Zoccali Galactic globular clusters. The galactic bulge. The initial mass function.

5. PhD Students Erika Labbe Prof. guide: D. Minniti Melina Bernsten Prof. guide: Juan Esteban Gonzalez Prof. guide: Jose Miguel Fernandez Prof guide: Sergio Flores Prof. guide: L. Infante Roberto Muñoz Prof guide: Daniela Villegas Prof. guide: D. Minniti Mario Riquelme Prof. guide: MA Students Rodrigo Contreras Prof. guide: M. Catelan Undergraduate Students Roberto Eugenio González Reyes Prof. guide : Gaspar Galaz Felipe Antonio Pérez Mejías Prof. guide : Dante Minniti Alejandra Castro Anich Prof. guide : M. Bañados Joaquín Patricio Prieto Brito Prof. guide : A. Reisenegger Carlos Roberto Contreras Velásquez Prof. guide : A. Clocchiatti María Clemencia Mora Herrera Prof. guide : M.A.Diaz Daniel Castillo Palma Prof. guide : D. Minniti Tomás Ignacio Andrade Weber Prof. guide : M.Bañados

6. ESO: Paranal and La Silla CTIO GEMINI CARNEGIE: Magellan Las Campanas Telescopes:

7. Network-wide project Supervisor Leopoldo Infante, Dante Minniti, Nelson Padilla Title ESO Large Programme to test the ALFA simulations with VLT+VIMOS One of the advantages that Catolica scientists can offer the LENAC is the access to a wide variety of small and large telescopes located in Chile. We propose to identify a spectroscopic galaxy survey that involves as many nodes as possible, and apply for an ESO Large Programme with VLT+VIMOS, in order to test the specific predictions of your simulations. PROJECTS

8. At Catolica Student projects PROJECTS

9. Supervisor Leopoldo Infante, Zheng, Ford Title Objects at Ultra High Redshifts to Probe the IGM Re-ionization One major challenge in astrophysics today is to determine the epoch when the intergalactic medium got re-ionized. For this, the most distant galaxies and quasars (z > 6) should be discovered. We are carrying out a project which combines archival HST/ACS z-band images and data from deep infrared imaging taken with large telescopes in Chile. This allow us to exploit the Ly Alpha break at 1216(1+z)A technique to identify dropouts at z > 6. Spectroscopic follow up of candidates is planned at VLT, Gemini and Magellan. Students and researchers are invited to collaborate in the various aspect of this project: e.g. NIR data reduction and analysis; spectroscopic and IR observations in Chile; discovery and analysis, candidates, etc. Supervisor Leopoldo Infante, Nelson Padilla Title Clustering of Galaxies and Small Groups of Galaxies, N(z,m), r_0(z,m) Structures in the Universe are characterized by their corresponding halo dark matter mass and by their occupation number, m (number of objects of a given class). By measuring velocity dispersion to determine masses, correlation lengths to understand their clustering properties and mean densities the bias parameter, which measures the relation between the mass and galaxy density field, can be determined. Once the bias is known, a mayor goal of the subject is to put constrains in the matter density Omega_m sigma_8 and in the shape of the primordial power spectrum of density perturbations.In this project a new scheme to select galaxy clusters is used, starting from small groups with two (cluster number richness, m=2) L>L* members to compact groups with at least five members (m=5). Then, for each m we study the clustering properties as a function of redshift. Large photometric catalogs on large fields are now being produced, eg. SDSS, RCS, XMM, etc. These data sets, at low redshifts, together with spectroscopic follow up will allow us for the first time to study the clustering properties of 2<m<5 groups with good statistics. At higher redshifts the ALHAMBRA survey will provide redshift distributions N(z,m) in narrow z bins. Spectroscopic follow up observations are being carried out with telescopes in the mayor observatories in Chile.This project will be underpinned by the use of mock catalogues which will allow a better understanding of the systematics present in the measurements obtained from the observations. These mock catalogues will have to be constructed specifically for each observational dataset used in this project, and will mimick as closely as possible several observational biases present in the data.

10. Supervisor Leopoldo Infante, Nelson Padilla, Carlton Baugh, Carlos Frenk Title Testing the Gaussian fluctuations paradigm with the clustering of groups and clusters of galaxies. The amplitude of clustering of dark matter haloes increases with halo mass. This has been measured recently for the 2PIGG(2dF) and SDSS, and very thoroughly for numerical simulations with Gaussian initial fluctuations. This increase is a consequence of the density field being roughly Gaussian, although non-Gaussian fields are also expected to produce this effect. In this project we will find out whether a different set of initial conditions provides a better match to the observations. In order to do this we will run a set of numerical simulations with density fields drawn from fluctuation distributions ranging from Gaussian to more exponential types, providing a new test of the Gaussian fluctuation hypothesis. Supervisor Dante Minniti (Catolica), Daniella Villegas (Catolica), M. Rejkuba (ESO) Title NGC5128 (Centaurus A), The Nearest Giant Elliptical Galaxy Even though sophisticated models exist, the formation histories of large galaxies are often difficult to test in detail. At a distance of about 4 Mpc, NGC 5128 (Centaurus A) is the nearest giant elliptical galaxy. It is also the nearest AGN, with a supermassive black hole, and a powerful radio source. It is also the nearest galaxy with shells, that contains a central dust lane, both signs of a recent merger. In addition, its globular cluster system is 10x that of our own galaxy. With large telescopes we are beginning to unveil the kinematics, star formation history, populations, abundances, globular clusters, etc, of this unique specimen.

11. Supervisor Gaspar Galaz Title Studying the low surface brightness galaxies from the SDSS With the advent of large aperture telescopes (VLT, Magellan, GEMINI, etc.) the detailed (high S/N spectroscopy, high spatial resolution, etc.) study of low surface brightness galaxies (LSBGs) become possible. These low stellar density galaxies are apparently dominated by dark-matter, following their rotation curves; furthermore, observational facts challenge current galaxy formation theories and stellar formation processes observed in other, high surface brightness, galaxies. For example, it is still unclear whether these LSBGs are the local counterpart of excess of blue galaxies observed at intermediate redshifts. This project proposes a detailed study (both statistical and follow-up) of LSBGs from the SDSS. In particular, LSBGs will be selected in the SDSS using different parameters (central surface brightness, colors, gas content when correlated with HI surveys, etc.). Results will be correlated with those obtained by Galaz et al (2002) for a small sample and, in particular, a detailed study of the stellar populations in their bulges is proposed: they contain the fossil stellar population which account for the past history of these elusive galaxies. We propose also the study of many properties of these galaxies as a function of local density and other survey statistical estimators. Student Roberto Assef Supervisor Leopoldo Infante Title Galaxy Pair Colours and Low-redshift Merge-rate This project consists of exploring the colours of galaxy pairs defined as two galaxies within 15 Kpc of each other, close enough for their dust to interact. The idea of the project is to see if this interaction is capable of inducing star formation in the pair. If this is the case, the member galaxies should be bluer than their isolated partners on the field. So far, we have studied this relation for galaxies within the magnitude range 18<r<20 (that is, around <z> = 0.23) from the SDSS catalogue. The next steps would include expanding this study for different redshifts, developing a relation capable of distinguishing true galaxy pairs without redshift information, and measuring the merger rate as a function of redshift, taking advantage of the new redshift surveys that have recently become available, such as the SDSS.

12. Mobility involving Catolica To Type Months MPA AT 12 Durham RT 6 IEEC RT 3 Toulouse RT 3 Cordoba RT 1 Sao Paulo RT 1 From Type Months IEEC RT 3 INAOE RT 2 Cordoba RT 1