Latest talks

List of all the talks in the archive, sorted by date.

Monday September 12, 2016
Mr. Joseph Putko, Ms. Martyna Chrulinska, Mr. Antoni Ramos Baudes, Mr. Rafel Luque Ramírez, Mr. Roke Cepeda Arroita and Mr. Pablo Doña Girón


Monday September 5, 2016
Dr. Matteo Monelli, Mr. Jorge A. Pérez
Instituto de Astrofísica de Canarias


In coincidence with the announcement of the call for proposal of the Spanish night CAT for semester 2017A, we present the new web page OOCC. This is the new astronomer portal of the IAC, and it targets the Spanish community with all the necessary information to access and observe with any telescope at both Observatorios Astronomicos de Canarias, that is the Observatorio del Teide and the Observatorio del Roque de los Muchachos. The new portal, developed by the IAC Telescope Operation Group in agreement with the Presidents of both the night and the solar CATs, supersedes the old and pages. In this talk we will present the most important aspects and possibilities of the portal.

Friday September 2, 2016
Prof. Jifeng Liu
National Astronomical Observatories of the Chinese Academy of Sciences


While ultraluminous supersoft X-ray sources (ULSs) bear features for intermediate mass black holes or very massive white dwarfs possibly close to Chandrasekhar mass limit, our recent discovery of processing relativistic baryonic jets from a prototype ULS in M81 demonstrate that they are not IMBHs or WDs, but black holes accreting at super-Eddington rates. This discovery strengthens the recent ideas that ULXs are stellar black holes with supercritical accretion, as demonstrated in the case of M101 ULX-1, and provides a vivid manifestation of what happens when a black hole devours too much, that is, it will generate thick disk winds and fire out sub-relativistic baryonic jets along the funnel as predicted by recent numerical simulations. 

Friday September 2, 2016
Prof. Gang Zhao
National Astronomical Observatories of China


The National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) was officially founded in April 2001 through the merger of several unites and was headquartered in Beijing, which was formerly called the Beijing Astronomical Observatory established in 1958. Aiming at the forefront of astronomical science, NAOC conducts cutting-edge astronomical studies, operates major national facilities and develops state-of-the-art technological innovations in China.  NAOC is one of the most important institutes for Astronomy in Chinese Academy of Sciences (CAS)  system, as well as in the whole country. I will briefly introduce NAOC, including the facilities, research and the international collaborations.

Thursday August 11, 2016
Dr. Devika Kamath
Universidad de Leuven


 In this talk I will present the our work on an exotic group  
of evolved objects: post-AGB and post-RGB stars and the excellent  
constraints they provide for single and binary star evolution and  
nucleosynthesis. These objects have also revealed new evolutionary  
channels and AGB nucleosynthesis which is vital for understanding the  
complex chemical evolution of our Galaxy as well as external galaxies.

Thursday July 28, 2016
Dr. Raúl Angulo


Numerical simulations have played a crucial role in the development of modern
cosmology and in the establishment of LCDM. In this talk, I will review the main 
results and the fundamental assumptions behind those dark matter simulations. 
I will focus on the internal structure of halos and report on recent results on the 
formation and evolution of the very first halos to form in cold dark matter cosmologies. 
Then, I will discuss on recent attempts to model and study dark matter in the 
continuum limit. I will show how such methods help to overcome known problems 
of N-body simulations, and also how it is possible to get new insights into dark 
matter dynamics.

Thursday June 30, 2016
Dr. Taketo Nagasaki
KEK Japan


We propose ground-based monitoring system for atmospheric water vapor based on wide-range spectra at 20 – 30 GHz and 50 – 60 GHz ranges. It  observes in these microwave range and estimates the thermodynamic environments in the atmosphere. These information can determine short-term forecasting and now casting of severe storms. Our system can catch rapid increase of water vapor before clouds generation. We employ cold receiver system to achieve a system temperature below the atmospheric radiations. We will present overview of the system, including status of development, and results of long-term monitoring in outside.

Thursday June 23, 2016
Dr. Sébastien Comerón
University of Oulu


The disc of galaxies is made of the superposition of a thin and a thick disc. Thick discs are seen in edge-on galaxies as excesses of light a few thin disc scale-heights above the mid-plane. Star formation occurs in the thin discs whereas thick discs are made of old stars. The formation mechanisms of thick discs are under debate. Thick discs might have formed either at high redshift on a short time-scale or might have been built slowly over the cosmic time. They may have an internal or an external origin. To solve the issue of the thick disc origin we studied the kinematics and the stellar populations of the nearby edge-on galaxies ESO 533-4 and ESO 243-49. We present the first Integral Field Unit (IFU) spectroscopy works with enough depth and quality to study the thick discs. This was done with VIMOS@VLT and MUSE@VLT.

Our results point that thick discs formed in a relatively short event at high redshift and that the thin disc has formed afterwards within it. We also find that the thick disc stars have an internal origin as opposed to have their stars accreted during encounters. The work regarding ESO 533-4 has recently been published in Comer?n et al. 2015, A&A, 584, 34.

Tuesday June 21, 2016
Dr. Enrico Corsaro
Service d'Astrophysique, IRFU/DRF-CNRS/CEA Saclay


Stars originate by the gravitational collapse of a turbulent molecular cloud of a diffuse medium, and
are often observed to form clusters. Stellar clusters therefore play an important role in our
understanding of star formation and of the dynamical processes at play. However, investigating the
cluster formation is difficult because the density of the molecular cloud undergoes a change of
many orders of magnitude. Hierarchical-step approaches to decompose the problem into different
stages are therefore required, as well as reliable assumptions on the initial conditions in the clouds.
In this talk I will report for the first time the use of the full potential of NASA Kepler
asteroseismic observations coupled with 3D numerical simulations, to put strong constraints on the
early formation stages of old open clusters. Thanks to a Bayesian peak bagging analysis of about 50
red giant members of NGC 6791 and NGC 6819, the two most populated open clusters observed
in the nominal Kepler mission, I derive a complete set of detailed oscillation mode properties for
each star, with thousands of oscillation modes characterized. I therefore show how these
asteroseismic properties lead to a discovery about the rotation history of stellar clusters. Finally,
the observational findings will be compared with hydrodynamical simulations for stellar cluster
formation to constrain the physical processes of turbulence, rotation, and magnetic fields that are
in action during the collapse of the progenitor cloud into a proto-cluster.

Thursday June 16, 2016
Mrs. Sara Bertran de Lis
Instituto de Astrofísica de Canarias (IAC)


The detection of chemical inhomogeities in the Galactic disk requires an oustanding precision in the abundance measurements and a thorough estimation of the uncertainties. So far, studies in alpha-elements in disk stars either do not reach the required precision, or comprise too small samples in the solar neighborhood. Thanks to the Apache Point Galactic Evolution Experiment (APOGEE), we have for the first time a large spectroscopic sample of about 100.000 disk stars, with data homogeneously obtained, reduced, and analyzed. Taking advantage of such database, we examine the distribution of oxygen-to-iron abundance ratio in stars across the Galactic disk. These data reveal that the square root of the star-to-star cosmic variance in the [O/Fe] at a given metallicity is about 0.03 to 0.04 dex in both the thin- and thick-disk populations. Measuring the spread in [O/Fe] and other abundance ratios can provide strong constraints for models of Galactic chemical evolution. In this talk we will describe how we arrived at this result, the calculation of uncertainties, and implications regarding the chemical evolution of the Galaxy.

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