Seminars and Colloquia at ESO Santiago

May 2024

24/05/24 (Friday)
11:00, Urania room (ESO, Santiago) | ESO Santiago
ESO Talk
Lecture — Fitting data, noise consideration, parameter estimation in the Bayesian framework
Elyar Sedaghati (ESO)

Abstract

A fundamental concept in observational astronomy is fitting complex models to data obtained from a multitude of instrumentation installed at a variety of telescopes. Such observations are accompanied by a convoluted array of noise sources imprinted on the obtained data. This together with the fundamental Poisson noise inherent to any data, makes model comparison even more challenging. Both parametric and non-parametric approaches to full noise consideration, such as wavelets and Gaussian Processes respectively, have been proposed.  I will present an example of how the consideration of the full covariance matrix, instead of just the variances, can lead to better estimation of precision and accuracy. Finally, I will go through some basic concepts of how this formulation can be implemented in a Bayesian framework in order to obtain posterior probability distributions, from which optimal parameter values and their uncertainties are estimated, using Markov Chain Monte Carlo simulations.

15:30, Library (ESO, Vitacura) | ESO Santiago
TMT (30 minutes talk)
Talk — Analysing 3D images of nova shells with virtual reality
Julian Blasek (RWTH)

Abstract

Nova eruptions in cataclysmic variables occur when enough material has been accreted onto the surface of the white dwarf. As a result, the accumulated material is expelled into the interstellar medium, forming an expanding nova shell around the system. Understanding the physical processes that shape the morphology of nova shells is essential to fully comprehend how the ejection mechanism works during nova eruptions. As part of the Apocalypse Programme, several nova shells have been observed with MUSE. The MUSE data, like all IFU data, contain a spectrum for each spaxel in the field of view. The aim was to convert these data into three-dimensional images in various emission lines, to explore the shell morphology further. In my talk, I will present how we developed 3D images that can be explored on a PC or VR setup.

28/05/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
15:30, Library (ESO, Vitacura) | ESO Santiago
TMT (30 minutes talk)
Talk — TBD
Isabelle Codron (ESO Santiago)

Abstract

TBD

29/05/24 (Wednesday)
14:00, Library (ESO, Vitacura) | ESO Santiago
Python Coffee
Talk — Python Coffee: SHAP analysis for interpretable Machine Learning in Astrophysics
Rodrigo Carvajal (Universidade de Lisboa)

Abstract

It has been argued that traditional Machine Learning algorithms (and other data analysis tools) often lack transparency in how input observables influence the final output. These 'black boxes' can reach the right conclusions for the wrong reasons, damaging our analyses and interpretations. Lately, several tools have been developed to address these issues and open these black boxes, aiming to understand the source of their decisions. One of these tools is the SHapley Additive exPlanations (SHAP), which can give clues on the observables driving ML predictions, leading to better interpretation of models. I will introduce the use of the Python package SHAP with astrophysical examples, highlighting its power in high-dimensional analysis and the insights it can bring to decision-making processes.
15:30, Vitacura | ESO Santiago
TMT (30 minutes talk)
Talk — Speckle interferometry with the Gemini telescopes
Ricardo Salinas (Universidad de la Serena)

Abstract

While adaptive optics is the most widespread method to compensate for atmospheric turbulence, these methods are particularly difficult to implement in the optical regime given the technical challenges imposed by the short coherence times. An alternative to reach the diffraction limit of an optical telescope is provided by speckle interferometry, where, instead of real-time corrections, observations are obtained in timescales similar to the coherence time (a few ms), and the diffraction limit is recovered via a post-hoc reduction in Fourier space. In 2019, the Gemini telescopes commissioned two speckle interferometers, Zorro and 'Alopeke, owned by NASA Ames, which have remained as "permanent visiting" instruments since then. In this talk I will present the characteristics of these instruments, to then present a number of science cases where these instruments are particularly suited, mostly leaning to my own research on RR Lyrae in binary systems, and blue stragglers in hierarchical triplets

30/05/24 (Thursday)
15:30, Library (ESO, Vitacura) | ESO Santiago
TMT (30 minutes talk)
Talk — TBD
Alejandro Saravia (University of Virginia)

Abstract

TBD

31/05/24 (Friday)
15:30, Urania room (ESO, Santiago) | ESO Santiago
ESO Colloquium
Talk — The origins of the first mass extinction event
Michaël Marsset (ESO Vitacura)

Abstract

Studies of micrometeorites in mid-Ordovician limestones and Earth’s impact craters show that our planet witnessed a massive infall of ordinary L chondrite material ~466 million years ago that it believed to be at the origin of the first major mass extinction event (Schmitz et al. 2019). The breakup of a large asteroid in the main belt is the likely cause of this massive infall. In modern times, material originating from this breakup still dominates meteorite falls (~37% of all falls). I will present spectroscopic observations and dynamical evidence that we have identified the only plausible source of this catastrophic event and of the most abundant class of meteorites falling on Earth today.

June 2024

04/06/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
05/06/24 (Wednesday)
14:00, Library (ESO, Vitacura) | ESO Santiago
Python Coffee
Talk — Python Coffee: Numpyro
Bibiana Prinoth

Abstract

tbd

11/06/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
13/06/24 (Thursday)
15:30, Library (ESO, Vitacura) | ESO Santiago
TMT (30 minutes talk)
Talk — tbd
Kate Minker (Observatoire de la Côte d'Azur)

Abstract

tbd

18/06/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
19/06/24 (Wednesday)
15:30, Urania room (ESO, Santiago) | ESO Santiago
TMT (30 minutes talk)
Talk — TBD
Diogo Ribeiro (Max Planck Institute for extraterrestrial Physics)

Abstract

TBD

25/06/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH

July 2024

01/07/24 (Monday)
15:30, Library (ESO, Vitacura) | ESO Santiago
TMT (30 minutes talk)
Talk — TBD
Matteo Sadun Bordoni (Max Planck)

Abstract

TBD

02/07/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
09/07/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
10/07/24 (Wednesday)
15:30, Library (ESO, Vitacura) | ESO Santiago
TMT (30 minutes talk)
Talk — tbd
Katarzyna Nowak (University of Hertfordshire)

Abstract

tbd

11/07/24 (Thursday)
15:30, Licancabur meeting room | ESO Santiago
JAO Tech Talks
Lecture — NOEMA
Kirsty Butler (IRAM)

Abstract

TBD

16/07/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
23/07/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
30/07/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH

August 2024

06/08/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
13/08/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
20/08/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
27/08/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH

September 2024

03/09/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
10/09/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
17/09/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
24/09/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH

October 2024

01/10/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
08/10/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
15/10/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
22/10/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
29/10/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH

November 2024

05/11/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
12/11/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
19/11/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
26/11/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH

December 2024

03/12/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH
10/12/24 (Tuesday)
11:00, Miscanti room, ALMA building | ESO Santiago
JAO/ESO Astro-ph
Meeting — AstroPH