Recent Talks

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


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Tuesday June 4, 2024
Dr. Rahna Payyasseri Thanduparackal
CEFCA

Abstract

The Javalambre Photometric Local Survey (J-PLUS) is an ongoing 12-band photometric optical survey, observing thousands of square
degrees of the Northern hemisphere from the dedicated JAST/T80 telescope at the Observatorio Astrofísico de Javalambre.
The larger field of view (FoV), high spatial resolution, contiguous narrow band filters cover a wide wavelength (330-1100 nm)
of J-PLUS/J-PAS surveys act like a low resolution IFU, which is suitable for spatially resolved studies of galaxies. J-surveys have
large Field of view (FoV) and can offer large contiguous observing areas to understand the complete structure of all galaxies
and trace their environment without any pre-selection. In my talk, I will present the results from the spatially resolved study of Halpha 
emission line maps of nearby galaxies at z < 0.017 using JPLUS DR3. We validate our method to build the J-PLUS IFU (J-IFU) emission line maps
with other IFUs such as CALIFA, MANGA and MUSE. I will also present spatially resolved star-forming regions, its photospectra and star formation maps
of JPLUS galaxies.

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Friday May 17, 2024
Dr. Carine BRIAND, Dr. Pauline TEYSSEYRE
LESIA/ Paris Observatory

Abstract

 

The ionospheric D-layer (60 and 90km) is also called the “ignorosphere”, clearly indicating the level of knowledge on this atmospheric layer. Its electron content follows a daily cycle, but also the seasonal cycle of the solar UV flux radiation. In addition to these long-period variations, the D-layer electron density is submitted to much faster forcing, like geomagnetic storms, solar eruptions (hours) or lightning and Transient Luminous Events (seconds or less). The electron content of the D-layer controls the absorption of some radio waves and links the neutral atmosphere to the magnetosphere and radiation belts. The disturbances of the D-layer electron density can lead to HF communications disruption, a threat now identified by the International Civil Aviation Organization. The project focuses on two natural hazards: solar flares because they produce the strongest forcing of the D-layer, and the lightning strokes and Transient Luminous Events because their links to the D-layer are largely unclear. 
The D-layer is too high for balloons and too low for satellites. Therefore, it is inaccessible to continuous in situ measurements. The most widely used technique to study the D-layer consists of measuring the VLF emissions from man-made or natural origin. VLF modes propagate in the waveguide formed by the Earth and the ionosphere, with reduced loss (~2 dB/Mm), thus propagating very long distances. An increase in electron density alters the modes: the amplitude and phase are then affected, which provides an efficient way to detect, in real time, electron density variations. 
During this talk, we will detail the project VLF4IONS, and in particular, the network that is being built worldwide (including Tenerife).

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Friday April 19, 2024
Enol Matilla Blanco
IAC

Abstract

Diseño, construcción y primera luz del EMO-1, un observatorio casero con estación meteorológica integrada, monitoreo permanente del cielo y colaboración científica.

 

Youtube:
https://youtube.com/live/0PFICuLjOAE?feature=share


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Friday April 5, 2024
Pavel Nichita

Abstract

En esta charla se va a presentar los telescopios ATLAS y su integración en la red ATLAS dirigida por la Universidad de Hawaii. Vamos a hablar del estado actual del proyecto, tecnología que se utiliza en los telescopios y el stack software que lleva asociado.

 

Link Youtube:

https://youtube.com/live/37xMArgvyfI?feature=share


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Thursday March 21, 2024
Prof. Kentaro Nagamine
Osaka University

Abstract

In the field of modern cosmological studies, we like to think that we live in an era of "precision cosmology." However, our understanding of matter distribution on small scales is not quite there yet. This limitation stems from the feedback effects of supernovae and supermassive black holes, which alter the matter distribution on scales smaller than a few Mpc and impact star formation and galaxy evolution. I will discuss how surveys such as Subaru-PFS and DESI will enhance our understanding of the Universe's matter distribution. By observing galaxies and AGNs, we can infer the distribution of dark matter, gas, and metals with the support of theoretical modeling and numerical simulations. Specifically, I will explain how we can tighten the constraints on matter distribution on small scales and further refine our understanding of the Lambda-CDM model through IGM/CGM tomography and Lyman-alpha forest analysis. 


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Tuesday March 19, 2024
Prof. Aline Vidotto

Abstract

Activity of cool dwarf stars can reveal itself in the form of high-energy radiation (eg, enhanced X-ray coronal emission, flares) and particles (eg, winds, coronal mass ejections). Together, these phenomena shape the space weather around (exo)planets. Because most of the known exoplanets have significantly closer orbital distances than solar system planets, they are often embedded in much harsher particle and radiation environments, leading to stronger interactions between the exoplanet and its surrounding environment. In this talk I will present an overview of how stellar activity and outflows can induce and shape atmospheric escape in exoplanets. I will focus mostly on close-in gas giant planets, whose escaping atmospheres are somewhat easier to observe. I will then discuss how the observability of atmospheric escape, through spectroscopic transits, evolve on billions of years timescales.


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Thursday March 14, 2024
Laura Scholz
IAC

Abstract

The coupling between the baryonic cycle of galaxies and dark matter halo assembly is central to our understanding of galaxies, and yet, it remains a challenge for theoretical models and elusive to observations. In this talk, I report observational evidence demonstrating that different baryonic properties of nearby galaxies are controlled by their host halos. We map galaxy ages, metallicities and star formation histories across the stellar-to-halo mass relation for SDSS central galaxies using absorption optical spectra. In addition to stellar populations, we also investigate the stellar angular momentum, star formation rates and galaxy morphology across the stellar-to-total dynamical mass relation for CALIFA galaxies. We find that the scatter of both relations correlates with these galaxy properties, which are determined by the combined role of stellar and halo/total mass. Galaxies become older, more metal-rich and less rotationally supported, form the bulk of their stars earlier on and faster, have lower star formation rates and earlier-type morphologies as their stellar mass increases (at fixed halo/total mass). Furthermore, we also observe that the scatter of the star-forming main sequence is driven by galaxies that have experienced different evolutionary histories. We interpret our results as being driven by halo evolution, with galaxies/halos at different evolutionary stages modulating the variety of galaxy properties observed at fixed stellar mass. Our findings call for a revision of the sub-grid physics implementation in cosmological numerical simulations, in particular during the early stages of galaxy formation, and warn observational studies to account for the profound effect that halo formation time may have on measured galaxy properties.

 

Zoom Link: https://rediris.zoom.us/j/96210828127?pwd=Z25JdFg1bnpRTVBSQUdpTVlwUDgyQT09


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Friday March 8, 2024
Marcos Reyes García Talavera
IAC

Abstract

El objetivo de esta charla es presentar los recientes avances del sistema de Óptica Adaptativa de GTC (GTCAO). Se resumirán los resultados de las pruebas de aceptación en la sala AIV en abril de 2023; las dificultades y el éxito del transporte al ORM y la instalación en GTC en junio de 2023; la integración del sistema con el control del telescopio y los primeros resultados de las campañas de commissioning en cielo. Se repasará también brevemente el estado del resto de proyectos del programa, en concreto el sistema de Estrella Guía Láser y el instrumento GRANCAIN.

 

Youtube: https://youtube.com/live/T1TQNju3eEw


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Thursday February 22, 2024
Dr. GyuChul Myeong
University of Cambridge

Abstract

 

Recent advancements in large scale astronomical surveys have introduced a new era for Galactic archaeology. 
The combination of quality astrometric (Gaia) and chemical (e.g., APOGEE, GALAH) data provides us with a rich hyper-dimensional dataset up to ~1.8 billion stars, including the full six-dimensional phase space information and a variety of chemical abundances. 
Coupled with recent computational developments on numerical methods for dynamical analysis, we can construct an effective arena for chemo-dynamical study of our Galaxy. 
Understanding the Galaxy's formation/evolution and the governing physical process will help us to better understand the current LCDM picture in the galactic scale. 
With our chemo-dynamical approach, we study the Galactic assembly history and the origin of Galactic components as well as their associations, which involve a major Galactic merger event that vastly reshaped our Galaxy.

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Tuesday February 20, 2024
Marie-Lou Gendron-Marsolais
IAA

Abstract

 

The central black hole of active galaxies accretes large amounts of matter and powers jets of relativistic particles that can propagate beyond the host galaxy. Radio galaxies are particularly bright at ∼ GHz frequencies, when the accelerated electrons interact with the magnetic field and produce strong synchrotron emission. Such galaxies residing in clusters evolve in a hot, diffuse, X-ray emitting plasma (the intracluster medium, ICM) which is constantly perturbed, both internally by the outbursts of the central AGN, and externally from interactions with other clusters, groups, and individual galaxies. The ram pressure provided by the relative motion between a radio galaxy and the ICM can bend radio jets, producing a wide variety of distorted morphologies, clearly distinguishable from standard double radio galaxies: the so-called "bent-jet radio galaxies". The advent of high-sensitivity low radio frequency facilities (such as e.g. VLA, GMRT, LOFAR, MWA, MeerKAT, ASKAP) has recently shed new light on our conception of galaxy cluster's environments, resolving bent-jet radio galaxies and unveiling diffuse structures extending on large distances without a direct association with a host galaxy ("mini-halos", "halos", or "relics"), which origin remain unclear. Overall, the complete picture of diffuse radio emission in these environments is complex and the link between those various sources and the properties of clusters is not yet clear.
Located at a luminosity distance of 78.4 Mpc, the notorious Perseus cluster of galaxies has been the center of numerous discoveries, its proximity allowing high sensitivity and high resolution studies, revealing the physics of clusters at unprecedented levels of details. In this talk, I will present an overview of the deep multi-scale low radio frequency observations of the Perseus cluster obtained from the Karl G. Jansky Very Large Array. These observations have revealed a multitude of new structures associated with the radio lobes of several galaxies and the central mini-halo. Such work is paving the way for future radio telescopes such as the SKAO, which will uncover many more radio sources in these environments and open a new window on the unknown radio universe.

 

Zoom link: https://rediris.zoom.us/j/99761131815?pwd=QUN0ckRSZWJZQkh1aUxvSU9UNmtJUT09
Meeting ID: 997 6113 1815

Passcode: 164994



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Recent Talks