Latest talks

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


Video
Thursday October 13, 2016
Prof. Roger Barry
University of Colorado

Abstract

Global snow and ice cover (the "cryosphere") plays a major role in global climate and hydrology through a range of complex interactions and feedbacks, the best known of which is the ice - albedo feedback.  Snow and ice cover undergo marked seasonal and long term changes in extent and thickness. The perennial elements - the major ice sheets and permafrost - play a role in present-day regional and local climate and hydrology, but the large seasonal variations in snow cover and sea ice are of importance on continental to hemispheric scales. The characteristics of these variations, especially in the Northern Hemisphere, and evidence for recent trends in snow and sea ice extent are discussed.


Video
Tuesday October 4, 2016
Dr. Remco Van-Der-Burg
CEA (France)

Abstract

Galaxy clusters are the most massive gravitationally collapsed structures in the universe, and they have important cosmological and astrophysical applications. Measurements of the radial distribution of galaxies in clusters show how galaxies trace the underlying dark matter distribution, and provide constraints on the physics related to their evolution in these environments. I will present measurements on the radial distribution of galaxies in two cluster samples, which span about 8 Gyrs of lookback time. By matching local galaxy clusters to their progenitors at high redshift, we study how clusters assemble their stellar mass content. Interestingly, this suggests that the central part of the stellar mass distribution of local galaxy clusters is already in place at redshift, and any further growth seems to happen in an inside-out fashion. I will put these findings into context by comparing them to the results from dark matter simulations. I will also focus on the abundance and spatial distribution of ultra-diffuse galaxies (UDGs, which have the luminosities of dwarfs but sizes of giant galaxies) in clusters. These mysterious galaxies have been found to be surprisingly abundant in local clusters, but their origin remains puzzling. I will discuss what we can learn about the properties of UDGs by studying their abundance as a function of halo mass, and their radial distribution in these haloes.


Video
Thursday September 29, 2016
Dr. Fabian Schneider
Univeristy of Oxford

Abstract

Approximately 10 per cent of massive OBA main-sequence (MS) and pre-MS stars harbour strong, large-scale magnetic fields. At the same time, there is a dearth of magnetic stars in close binaries. A process generating strong magnetic fields only in some stars must be responsible and several channels for the formation of magnetic massive stars have been proposed. In this talk, I will present recent results on the origin and evolution of such strong surface magnetic fields. Regarding the origin, mergers of MS and pre-MS stars have been proposed to form magnetic stars and I will highlight a method to probe this hypothesis observationally. Applying this new method to two magnetic massive stars, we find that they are indeed consistent with being MS merger products. Utilising a large sample of magnetic and non-magnetic OB stars, I will show that there is a dearth of evolved magnetic stars that suggests that magnetic fields disappear over time. I will argue that this is most likely caused by decaying magnetic fields.


Video
Tuesday September 13, 2016
Dr. Marc Balcells
ING

Abstract

An exciting series of changes are taking place at the venerable WHT and INT on La Palma. WEAVE, the next generation multi-fibre spectrograph is being completed for the WHT prime focus. Once built, it will carry out massive surveys of stars, the Milky Way, galaxy evolution and cosmology. At the INT, the HARPS3 high-resolution stabilized spectrograph is being built. It will provide the ING communities with a world-class exoplanet research tool. This talk will address the observing opportunities brought by these two instruments, their development calendars, and ING’s plans to retain additional instrumentation for the open time. I will describe how the telescopes will be operated, both in the survey time and the open, TAC time.


Video
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

Abstract


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

Abstract

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 www.iac.es/cat and www.iac.es/telescopes pages. In this talk we will present the most important aspects and possibilities of the portal.


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

Abstract

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. 


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

Abstract

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.


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

Abstract

 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.

Video
Thursday July 28, 2016
Dr. Raúl Angulo
CEFCA

Abstract

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.


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