News


New web-tool: Online Calculator RESoRt (Radio Emission Star Formation Rate)

The online calculator RESoRt (Radio Emission Star formation Rate) is a tool for determining the star formation rate (SFR) from the non-thermal galactic radio flux or vice versa.

In short, the physical background for a connection between the SFR and the radio flux is the following:
Non-thermal long-wavelength photons are emitted by highly energetic charged particles that travel in spiral motion around the interstellar magnetic field lines. These cosmic rays are connected to star formation as they are produced in supernova shock fronts. The link between synchrotron emission and the SFR is, however, not direct because the cosmic ray spectrum is affected by various processes, such as inverse Compton scattering, bremsstrahlung, ionization of the interstellar medium, interaction with the interstellar radiation field, and galactic outflows. Especially in galaxies with high gas densities, cosmic rays lose a large fraction of their energy via ionization. As a result, the radio flux does not contain any information about the SFR below a critical radio frequency.More details and the calculator itself can be found here:
astro.udec.cl/resort


Anillo ACT172033 "Formation and Growth of Supermassive Black Holes"

A new Conicyt-Anillo project exploring the formation and growth of supermassive black holes has been approved on December 29 2017. The program is led by Prof. Dominik Schleicher, and will make use both of state-of-the-art numerical simulations, as well as world-leading observational techniques, including activities related to the Event Horizon Telescope and the NuSTAR satellite. The program includes professors from Universidad de Concepcion (Neil Nagar, Stefano Bovino), Universidad de Valparaiso (Patricia Arevalo) and Pontificia Universidad Catolica de Chile (Ezequiel Treister). More information can be found on the webpage of the Anillo: www.astro.udec.cl/black_hole_anillo/


Theory & Starformation Group won Quimal

With the Quimal grant we will be able to buy the largest and fastest shared memory computer in the whole of Chile.

This machine will be dedicated to run astro-chemical networks.

Please stay tuned for more information soon.


German-Chilean Workshop "Current and future perspectives of chemical modeling in astrophysics"

The Theory and Star Formation Group was part organiser of the successful astro-chemistry workshop held in Hamburg, Germany. A large fraction of our group was present at this meeting.

Visit at Hamburg University for collaborations in the framework of the international project "The formation and evolution of the first stellar clusters", and joint organization of the workshop "Current and future perspectives of chemical modeling in astrophysics".

More information can be found here


Third Chilean Workshop on Theoretical and Numerical Astrophysics on June 29th 2017 was a great success

On Thursday, June 29th, 2017 the Theory and Star Formation group hosted the third Chilean Workshop on Theoretica and Numerical Astrophysics. About 25 participants from all over Chile (Antofagasta, La Serena, Santiago and Concepcion) gathered to exchange their latest results. This event gives astronomers and especially astronomy students, working in theory and numerical modelling the chance to get to know each other even though they work in completely different fields.

More Information

The meeting appeared in the university press: Link


"First Stars VI" will be held in Concepcion

The next international conference in the prestigious "First Stars" series will be held in Concepción, Chile in 2020. The Theory and Star Formation Group at the Department of Astronomy won the competition to host the next meeting.


New Web-tool for the Applegate Mechansim

Our group has developed a unique web-tool to calculate the magnetic activity in Binary Stars via the Applegate Mechanism. This work is part of a joint project with the Hamburg Observatory, Germany.

This module allows to calculate whether eclipsing time variations of a given magnitude can be produced via magnetic activity, specifically by what is referred to as the Applegate mechanism. This formalism considers changes in the stellar quadrupole moment, arising as a result of angular momentum redistribution due to magnetic activity. The change in the quadrupole moment couples to the binary orbit via gravity, thus inducing the period change. The calculation below assesses the required energy for the change in the quadrupole moment, which is compared to the energy that is produced by the star. The latter is crucial to assess the feasibility of the Applegate mechanism within a specific system.

Have a look for yourself: Applegate


Postdoctoral position on “Accretion physics of nearby AGN: Preparation for the Event Horizon Telescope“

The theory group in the Astronomy Department at the Universidad de Concepción (Chile) invites applications for a two-year postdoctoral position on “Accretion physics of nearby AGN: Preparation for the Event Horizon Telescope“. The objective of the project is to explore the accretion physics of AGN to derive testable predictions for the Event Horizon Telescope (EHT, http://www.eventhorizontelescope.org/).

The theory group in Concepción is the largest theoretical astrophysics group in Chile, consisting of Prof. M. Fellhauer and Prof. D. Schleicher, two recently hired postdocs and more than 10 students. The project will be jointly pursued with the UdeC Radio Lab (Profs. N. Nagar and R. Reeves), which is directly involved in the EHT and has contributed to its instrumentation via the ALMA Phasing Project.

Applicants for the position should hold a PhD in astronomy or a related field and have experience in computational modeling and the physics of accretion disks, AGN or black hole metrics. Interested candidates should send a cover letter, a CV including a list of publications and a 3-page research statement as a single pdf file to Prof. Dominik Schleicher (dschleicher (at) astro-udec.cl) and arrange for two letters of recommendation. The selection of candidates starts on April 1st, with potential starting dates from September 2017. Applications will be accepted until the position is filled.

Included benefits: In addition to a competitive salary, we provide contributions to the health care insurance as well as an annual travel budget of about 3000 USD.

Contact:
Prof. Dr. Dominik Schleicher
dschleicher@udec.cl
Departamento de Astronomía
Casilla 160-C
Universidad de Concepción
Concepción, Chile

An extensive catalogue of early-type galaxies in the nearby Universe

We present a catalogue of 1715 early-type galaxies from the literature, spanning the luminosity range from faint dwarf spheroidal galaxies to giant elliptical galaxies. The aim of this catalogue is to be one of the most comprehensive and publicly available collections of data on early-type galaxies. The emphasis in this catalogue lies on dwarf elliptical galaxies, for which some samples with detailed data have been published recently. For almost all of the early-type galaxies included in it, this catalogue contains data on their locations, distances, redshifts, half-light radii, the masses of their stellar populations and apparent magnitudes in various passbands. Data on metallicity and various colours are available for a majority of the galaxies presented here, including many of the rather faint early-type galaxies in the Local Group. The data on magnitudes, colours, metallicities and masses of the stellar populations is supplemented with entries that are based on fits to data from simple stellar population models and existing data from observations. Also, some simple transformations have been applied to the data on magnitudes, colours and metallicities in this catalog, in order to increase the homogeneity of this data. Estimates on the Sersic profiles, internal velocity dispersions, maximum rotational velocities, dynamical masses and ages are listed for several hundreds of the galaxies in this catalogue. Finally, each quantity listed in this catalogue is accompanied with information on its source, so that users of this catalogue can easily exclude data that they do not consider as reliable enough for their purposes.
( Dabringhausen & Fellhauer, 2016, MNRAS, 460, 4492)

The catalogue files can be downloaded here.


New international project on “The formation and evolution of the first stellar clusters”

The theory group in the astronomy department of the Universidad de Concepción (Prof. Dr. D. Schleicher (PI) and Prof. Dr. M. Fellhauer (Co-I)) has received funding for an international project on “The formation and evolution of the first stellar clusters” (Concurso Proyectos Internacionales de Investigación, Convocatoria 2015). The project aims to explore the formation of the first stellar clusters, forming about 100 million years after the Big Bang. A central goal is to explore the impact of metals and dust on the fragmentation of star-forming clouds, to understand the typical stellar masses in the first clusters as well as their overall properties. For this purpose, the group will pursue high-resolution hydrodynamical simulations including the modeling of chemistry and cooling.

The project will be carried out in collaboration with Hamburg Observatory over a timescale of three years, and provides funding for travel, stipends for students as well as a postdoctoral researcher.

© Theory & Star Formation Group 2017