Colloquia

Talks given by high profile astronomers and scientists.


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Thursday January 30, 2020
Prof. Javier Garcia Campayo
Universidad de Zaragoza

Abstract

Mindfulness o atención plena es un estado de la mente que permite estar atento al momento presente con aceptación. Y describe también la técnica psicológica que permite alcanzar este estado. Mindfulness se asocia a una gran bienestar físico y psicológico y por eso su práctica se está extendiendo a nivel internacional y se aplica en el área de la salud, la educación y las organizaciones.
En el coloquio sentaremos las bases teóricas de mindfulness, realizaremos algunas prácticas básicas y analizaremos los mecanismos de acción y la utilidad de mindfulness en el día a día.


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Friday December 13, 2019
Prof. J. R. Kuhn
IfA, Hawaii

Abstract

We should find life beyond the solar system ("exolife") within a decade. This will require optical instruments that can perform exoplanet direct imaging.  There are good reasons to expect that telescopes from the ground will lead this search. Unfortunately, none of the currently envisioned large telescopes are optimal for detecting and measuring the emitted or reflected starlight from life-bearing exoplanets. This talk will describe what a 20-100m-class optical telescope would look like and could do if it were designed to solve exoplanet imaging problems. Such a telescope could be initiated today using technologies that are either currently available or under vigorous development.


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Thursday December 12, 2019
Dr. Marc Pinsonneault
Ohio State university

Abstract

Time-domain space missions have revolutionized our understanding of stellar physics and stellar populations. Virtually all evolved stars can be detected as oscillators in missions such as Kepler, K2, TESS and PLATO.  Asteroseismology, or the study of stellar oscillations, can be combined with spectroscopy to infer masses, radii and ages for very large samples of stars.  This asteroseismic data can also be used to train machine learning tools to infer ages for even larger stellar population studies, sampling a large fraction of the volume of the Milky Way galaxy. In this talk I demonstrate that asteroseismic radii are in excellent agreement with those inferred using Gaia and spectroscopic data; this demonstrates that the current asteroseismic data is precise and accurate at the 1-2% level.  Major new catalogs for Kepler and K2 data are nearing completion, and I present initial results from both. We find unexpected age patterns in stars though to be chemically old, illustrating the power of age information for Galactic archeology.  Prospects for future progress in the TESS era will also be discussed.


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Thursday December 5, 2019
Prof. Raffaella Morganti
ASTRON, Netherlands

Abstract

Our view of the gas and its physical conditions in the central region of AGN has been enriched by the discover of fast and massive outflows of HI and molecular gas. These outflows can be driven by radiation/winds but also by the interaction of the radio plasma with the ISM. Understanding the origin and quantifying their impact requires to trace their location and derive their physical conditions (density of the gas, mass, mass outflow rate and kinetic energy of the outflow etc.). Particularly interesting has been the finding that in the first phase of their life, jet in radio galaxies can be particularly effective in driving such outflows. This crucial phase is at the heart of the idea of feedback, therefore particularly relevant for studying feedback in action.

 

In this talk, I will present some of the results we have obtained to trace jet-driven HI and molecular gas outflows down to scales ranging from hundred to tens of pc. The impact of low-power radio jets will be discussed and the comparison with the predictions from numerical simulations will also be presented.

Outflows of up to few hundred Msun/yr have been found in molecular gas using ALMA while the HI observed with VLBI is showing that the outflowing gas is clumpy as also predicted from numerical simulations. I will describe the kinematics of the gas and its conditions and the relevance they may have for feedback.    


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Friday November 8, 2019
Prof. Andrej Prsa
Villanova University

Abstract

Most of what we know about the masses and radii of stars comes from the studies of eclipsing binary stars (EBs). As the physical principles that govern the motion are well understood, modelling EB data represents a tractable geometrical problem. The attained accuracy of fundamental parameters is ~2-3% in the best possible cases (Torres et al. 2010), which plays a paramount role in stellar astrophysics: these results are used to calibrate the mass-radius relationship, critically test stellar evolution models, provide fundamental parameters (temperature, luminosity, mass and radius) for stellar and substellar objects across the main sequence, and anchor the distance scale. Given that so much in stellar astrophysics hinges critically on the values derived from EBs, we naturally wonder whether there are any circumstances that would allow us to beat down the uncertainties by another order of magnitude, say to a ~0.2-0.3% level, and thus achieve a 10-fold increase in calibration and gauge reliability. This could be done if the correlations between parameters were somehow reduced, and solution degeneracy somehow broken. If, for example, we had a third star in the system that happens to eclipse the binary, then the shapes of extraneous eclipses in a light curve would constrain the orbital inclination and stellar radii much more than the binary eclipses alone.
In this talk, I will discuss these and similar considerations and show what Kepler, K2 and TESS missions brought to the table.


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Thursday October 10, 2019
Prof. Paul Abell
NASA

Abstract

A major goal for NASA's human spaceflight program is to send astronauts to the Moon and beyond in the coming decades. The first missions would focus on exploration of the Moon with the intent of developing the technologies and capabilities to then proceed on to Mars.  

However, there are many objects that show promise as future destinations beyond the Moon, which do not require the extensive mission capabilities or durations required for Mars exploration. These objects are known as Near-Earth Objects (NEOs) and would undoubtedly provide a great deal of technical and engineering data on spacecraft operations for future human space exploration and serve as stepping stones for NASA’s efforts to reach Mars.  A subset of these objects has been identified within the ongoing investigation of the NASA Near-Earth Object Human Space Flight Accessible Targets Study (NHATS).

Information obtained from a human investigation of a NEO, together with ground-based observations and prior spacecraft investigations of asteroids and comets (e.g., Hayabusa2 and OSIRIS-REx), will provide a real measure of ground truth to data obtained from terrestrial meteorite collections.  In addition, robotic precursor and human exploration missions to NEOs would allow NASA and its international partners to gain operational experience in performing complex tasks (e.g., sample collection, deployment of payloads, retrieval of payloads, etc.) with crew, robots, and spacecraft under microgravity conditions at or near the surface of a small body.  This would provide an important synergy between the worldwide Science and Exploration communities, which will be crucial for development of future international deep space exploration architectures and has potential benefits for future exploration of destinations beyond the Earth-Moon system (e.g., Mars).


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Thursday October 3, 2019
Prof. Michael Kramer
Director MPI Radioastronomie

Abstract

We are living in a golden era for testing gravitational physics with precision experiments. This talk will present new results using a variety of tests with radio astronomy, ranging from binary pulsars to imaging black holes in the centre of galaxies. These results will be placed in context of other ongoing experiments, such as detecting gravitational wave with ground-based detectors or pulsar timing arrays, before giving an outlook into the future.


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Thursday July 25, 2019
Prof. Mike Barlow
University College London

Abstract

Until the advent in the late 1990’s of sensitive submillimetre arrays such as SCUBA, it was generally thought that the main sources for the interstellar dust found in galaxies were the dusty outflows from evolved AGB stars and M supergiants, although a dust contribution from supernovae had long been predicted on theoretical grounds. The detection at submillimetre wavelengths of very large dust masses in some high redshift galaxies emitting less than a billion years after the Big Bang led to a more serious consideration of core-collapse supernovae (CCSNe) from massive stars as major dust contributors. KAO and Spitzer mid-infrared observations confirmed that CCSN ejecta could form dust but it was not until the Herschel mission and subsequent ALMA observations that direct evidence has been obtained for the presence of significantly large masses of cold dust in young CCSN remnants. As well as using infrared spectral energy distributions to measure the amounts of dust forming in CCSN ejecta, dust masses can also be quantified from the analysis of red-blue asymmetries in their late-time optical emission line profiles. I will describe current results from these methods for estimating ejecta dust masses, and their implications.


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Thursday June 6, 2019
Prof. Jon Marcaide
University of Valencia

Abstract

Supernova SN1987A in the Large Magellanic Cloud offers an unprecedented opportunity to tackle fundamental issues of supernova explosions: dust and molecule formation, interaction with the circumstellar medium, particle acceleration, pulsar formation, etc. Since 2011, instruments like ALMA have been fundamental for such endeavor. Tomographic techniques have recently permitted to obtain 3D-images of the molecular emission. High-resolution images of dust emission have recently been obtained. All those results, compared with predictions from hydro-dynamical simulations, are paving the way to a better understanding of supernovae explosions. In the talk, the main results will be highlighted with emphasis on the advances produced since 2017 in the understanding of the structure of the inner ejecta or debris.


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Thursday February 28, 2019
Prof. Alex Fullerton
Space Telescope Science Institute

Abstract

The growth of astrophysical understanding typically results fromthe constructive interplay between theoretical ideas andobservational insights, with each mode of exploration drivingprogress at different times. The result is invariably a morecomplicated but richer picture of the phenomenon than initiallyenvisaged, as well as deeper appreciation of the behavior ofcomplex systems.In this talk, I will use the development of our understanding ofthe structure of outflows from massive O- and B-type stars toillustrate this collaborative “dance”. Starting from the smooth,spherically symmetric models for radiatively driven windsdeveloped in the late 1960s, our view of these outflows hasevolved to include the growth of inhomogeneities on a variety ofspatial scales. Explanations for the origin of this structure havein turn prompted the realization that non-radiative processesmust also shape the emergence of the wind from the stellarphotosphere. Consequently, O- and B-type stars are morecomplicated – and interesting! – objects than often thought.While many fruitful avenues of research remain to be explored,the current paradigm provides a (mostly) self-consistent pictureof massive stars and their outflows.



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