Seminars

ViodVidTuesday August 13rd, 14:00

The Star Formation Properties of Starbursts: A Multiwavelength Bayesian Study

Juan Rafael Martínez, Ph.D.

Harvard Center for Astrophysics (U.S.)

Abstract

Starbursts are the most luminous and massive environments of star formation in the Universe. Although large multiwavelength datasets have been collected for a large number of starburst regions and galaxies, and several models have been proposed to explain them, our understanding of the physical mechanisms that activate them is still poor. One scenario is that they are triggered by galaxy interactions that compress the gas into small regions, producing the massive collapse of large gas reservoirs. Nevertheless, the relation between the global star-forming properties of these systems and the properties of the massive stars and the interstellar medium (ISM) at smaller scales remains unexplored. I will offer a possible connection between the overall multi-wavelength emission properties of starbursts and the internal physics that control the evolution of individual HII regions. I will present CHIBURST, a novel Monte-Carlo Bayesian method that fits the multi-wavelength SEDs (and spectra) of star-forming systems and returns probability distribution functions for model parameters together with the results of applying the method to the SEDs of a set of interacting galaxies.

Video

Presentation

(Pending)

Thursday August 15th, 14:00

Magnetic constraints on the habitability of exoearths and exomoons

Prof. Jorge I. Zuluaga

FACom / IF / FCEN / UdeA

Abstract

Surface habitability of planetary environments is essentially constrained by two basic and related conditions: 1) the existence of a thick enough atmosphere and 2) proper levels of insolation or other sources of energy able to guarantee the right temperatures required for the existence of surface liquid water. Now it is widely accepted that magnetic fields play a central role into determining if a planet is able to preserve a dense enough atmosphere or the right content of volatiles required for habitability. In the Solar System Venus and Mars provide examples of planets that, though located inside the Radiative Habitable Zone (RHZ), lack a protective magnetic field and have lost their inventory of water or most of their early atmospheric content by a combination of thermal and non-thermal atmospheric losses. We present here a review of the role that magnetic fields would have at constraining the habitability of planetary environments, both in the case of Earth-like planets and super-Earths (exoearths) and for the case of exomoons around giant planets in the RHZ of their host stars.

Video

Presentation

(Pending)

Friday August 16th, 14:00

Properties of the cosmic mass distribution: Halos environments and galaxies

Prof. Juan C. Muñoz

FACom / IF / FCEN / UdeA

Abstract

In the first part of this seminar, we will present briefly the current projects under development in the line of galaxies and cosmology in the Group. In the second part, we will present in some detail some work on the Properties of the cosmic mass distribution, in particular, we combine results from numerical simulations of the formation of structures in the universe with observational results of galaxy redshift surveys to study the spatial distribution of mass in the large scale structure. Using cosmological N-body simulations we study the properties of the distribution of mass in and around dark matter halos and relate it to the assembly history of the dark matter halo and its environment. Using data from the seventh data release of the Sloan Digital Sky Survey (SDSS) we present an improved technique to identify galaxy groups and dark halos in the volume of the survey. We show that the technique indeed produces realistic galaxy groups and provide a realistic mass assignment. Using the known density distribution of dark matter in the neighborhood of dark halos and the halo catalogs obtained from the SDSS we perform reconstructions of the cosmic mass density field.

Video

Presentation

(Pending)

Tuesday August 20th, 14:00

An Evolutionary Diagram for Comets

Prof. Ignacio Ferrin

FACom / IF / FCEN / UdeA

Abstract

There are three comet reservoirs: the Oort Cloud, the Kuiper Belt

and the asteroidal belt. Due to their particular circumstances, it is

expected that the time evolution of the comets populating them will be

different. In stellar astrophysics the Herprung-Russell diagram is

famous for depicting the evolution of different types of stars. There

is no equivalent diagram for comets. In this work we will show that

the diagram of remaining revolutions, RR, versus the mass-loss age,

MLAGE (pronounces like "milage"), separates clearly the location

of the three different reservoirs and exhibits evolutionary paths. The

diagram shows the evolution of suffocationg comets and sublimating

comets. The Dead Dates, DD, are calculated and the border

suffocating-sublimating is shown. It is expected that this diagram

will be used to describe the evolutionary paths of comets. A full

theoretical description of these paths is non-existing at the present

time.