Recent Talks

Current intelligent systems mainly make "predictions". That is, given an input, they estimate the most probable value of the output. These systems have many limitations, they can be easily confused when presented with a different case from their training set and they cannot explain how they arrive to a certain result. Causal models are an alternative to extend the capabilities of current systems; explain the reasons for certain decisions, predict the effect of interventions and imagine alternative situations. In this talk, I will present an introduction to causal models, in particular to causal graphical models. We will see how we can make inferences based on these models: predictions and counterfactuals; as well as learning causal models from data. I will illustrate the application of causal models in various domains: estimation of effective connectivity in the brain, causal modeling of COVID-19, and incorporating causal models in reinforcement learning and its application in robotics. Finally, I will discuss some potential applications of causal modeling in astrophysics.

Gone are the days when we used workstations as our main day to day
computer. Backing-up your data has always been important, but the risks
were much fewer then. Today, when most of us use a laptop as our main
computer, the risks are much higher: added to human error, disk
failures, etc. we have to consider that losing, dropping or getting your
laptop stolen is a real possibility, which brings the added risk of
getting your sensitive data accessed by prying eyes.

In this talk I will share my overall backup plan. While my setting is
likely more complicated than that of most of you, hopefully you can mix
& match the strategies and tools that I use (mainly Borg, but also
Timeshift, Clonezilla, Syncthing, gocryptfs, ...) to suit your needs.

While a complete and thorough backup plan might take some time to
prepare and execute, you shouldn't postpone it. Something is better than
nothing!, and you can start with something very simple, which can be
very easy to implement, and can be improved over time.

CONCERTO (CarbON CII line in post-rEionization and ReionizaTiOn) is a low-resolution spectrometer with an instantaneous field-of-view of 18.6, operating in the 130—310 GHz transparent atmospheric window. It is installed on the 12-meter Atacama Pathfinder Experiment (APEX) telescope at 5 100 m above sea level. The Fourier transform spectrometer (FTS) contains two focal planes hosting a total of 4 304 kinetic inductance detectors. The FTS interferometric pattern is recorded on the fly while continuously scanning the sky. One of the goals of CONCERTO is to characterize the large-scale structure of the Universe by observing the integrated emission from unresolved galaxies via the line intensity mapping technique. In this presentation, I will introduce the CONCERTO instrument and show some first results.

As the number and variety of communications satellites proliferate in the rapidly accelerating New Space Age, specialists and lay observers alike have weighed the implications of a crowded orbital environment for astronomical research. The satellite launch tempo has recently increased dramatically, but conflict over the safe use of outer space has a much longer history. This talk will focus on similar debates surrounding experimental communications satellites from the late 1950s and early 1960s, notably a controversial test system known as Project West Ford. Astronomers have long acted as environmental watchdogs for outer space even as the power landscape in the international aerospace industry shifted during the decades since West Ford. What lessons might current astronomers take from past conflicts over the integrity of the night sky to address contemporary and future risk?

Pequeñas charlas consecutivas de 5 minutos sobre el trabajo de los becarios de verano en el IAC.

Youtube:

https://youtube.com/live/HrVzwfY33bQ?feature=share

The combination of stellar proper motions measured by the Gaia mission with spectroscopic radial velocities has recently enabled the precise determination of the
orbits of Milky Way stars and globular clusters. The information on their dynamics, coupled with existing chemical information, has allowed us to unravel many unknowns on their
origin and evolution, as well as on the assembly history of the Milky Way itself. In this talk I will present the most recent results on this topic, focusing on how globular
clusters can be superior tracers of the Milky Way build-up, and introducing a project, named CARMA, that aims at using globular cluster ages to characterise the most important
merger events experienced by our Galaxy.

Pequeñas charlas consecutivas de 5 minutos sobre el trabajo de los becarios de verano en el IAC.

Entrar Zoom Reunión
https://rediris.zoom.us/j/89609059257

ID de reunión: 896 0905 9257

Planets orbiting close to hot stars experience intense extreme-ultraviolet radiation, potentially leading to atmosphere evaporation and to thermal dissociation of molecules. However, this extreme regime remains mainly unexplored due to observational challenges. Only a single known ultra-hot giant planet, KELT-9b, receives enough ultraviolet radiation for molecular dissociation, with a day-side temperature of ~4,600K. An alternative approach uses irradiated brown dwarfs as hot-Jupiter analogues. With atmospheres and radii similar to those of giant planets, brown dwarfs orbiting close to hot Earth-sized white dwarf stars can be directly detected above the glare of the star.

In this talk I will present the discovery of an extremely irradiated low-mass companion to the hot white dwarf WD0032–317, focusing on the observational aspects of the discovery. Our analysis indicates a day-side temperature of ~8,000K, and a day-to-night temperature difference of ~6,000K. The amount of extreme-ultraviolet radiation received by WD0032–317B is equivalent to that received by planets orbiting close to stars as hot as late B-type stars, and about 5,600 times higher than that of KELT-9b. With a mass of ~75–88 Jupiter masses, this near-hydrogen-burning-limit object is potentially one of the most massive brown dwarfs known.

Simons Observatory (SO) is a new Cosmic Microwave Background telescope currently under construction in the Atacama Desert, close to ALMA and other recent CMB telescopes. It will have six small aperture (42cm) telescopes (SATs), and one large aperture (6m) telescope (LAT), observing at 30-280GHz (1-10mm) using transition edge sensors (TES) and kinetic inductance detectors (KIDs). As well as observing the polarisation of the CMB to unprecedented sensitivity, the LAT will perform a constant survey at higher angular resolution, enabling the systematic detection of transient sources in the submm, with large overlap of optical surveys such as LSST, DESI and DES. As well as giving an overview of SO, I summarise the types of transient sources that are expected to be seen by SO, including flaring stars, quasars, asteroids, and man-made satellites.