(Português) Colóquio: Harald Bock (CNRS e Bordeaux) – seminários Física e Química

10/04/2026 14:00

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O Programa de Pós-Graduação em Física convida para o colóquio:

“The Glass Transition and Delayed Luminescence in Columnar Mesophases”*
Dr. Harald Bock, Centre de Recherche Paul Pascal, CNRS & Univ. Bordeaux, France

*Evento de reposição da disciplina seminários

Resumo:
Columnar liquid crystals, made of stacks of aromatic disk-shaped molecules, are alignable viscous fluids that allow anisotropic migration of charges and of excited states. They may go through a glass transition, yielding an anisotropic solid with improved robustness. The proximity of parallel chromophores also favors radiative triplet-triplet recombination to give delayed fluorescence. I will discuss our recent findings in this field.

Data: 14 de abril de 2026 (terça-feira) – Horário: 10h
Local: Auditório Faruk Nome, Departamento de Química – UFSC

(Português) Colóquio: Hin Leung (Edinburgh) – online

06/04/2026 18:41

Sorry, this entry is only available in Brazilian Portuguese. For the sake of viewer convenience, the content is shown below in the alternative language. You may click the link to switch the active language.

O Programa de Pós-Graduação em Física convida para o colóquio:

“Mapping the shutting down of star formation from the local universe to the first galaxies”*

Dr Hin Leung, Royal Observatory of Edinburgh, UK

*Evento de presença obrigatória da disciplina seminários

Resumo:
From large galaxy surveys in the local universe, we find galaxies that are star-forming and galaxies that have mostly stopped forming stars. Those that are no longer forming stars must have at some point quenched their ongoing star formation and evolved passively to achieve the current “red and dead” state. However, the precise physical drivers of this quenching process are still highly debated.

In this talk, I will show results from studying recently quenched galaxies in the local universe. We found that a majority of these galaxies became significantly more metal-rich over a short period, indicating that whatever led to their quenching must also inflate their metal abundance without significant dilution from inflowing metal-poor gas. From looking at spatially resolved information collected in spectroscopic surveys, and applying a novel Hierarchical Bayesian modelling approach to include radial gradients of regional properties, we found evidence that their recent quenching could be caused by mergers with neighbouring galaxies.

Moving to more distant galaxies, from a sample of 14 massive quenched galaxies observed by JWST within 2 billion years after the Big Bang, we found strong evidence for “downsizing” to already be in place at early times. This means more massive galaxies formed earlier than less massive galaxies. Some of these most massive cases might be “cosmology-breaking”, where they are more massive than what a galaxy could reach in the same time predicted by lambda CDM, even with 100% baryonic assembly efficiency. From a broad search for all early and massive quenched galaxies, we report that almost all current cosmological simulations are under-predicting the number densities of these objects by ~2x. These suggest that substantial revisions to our models of early galaxy formation and quenching are needed.

Data: 10 de abril de 2026 (sexta-feira) – Horário: 10h15min
Link de acesso a sala virtual: https://conferenciaweb.rnp.br/ufsc/ppgfsc

Researcher from PPGFSC-UFSC participates in new international survey to investigate the center of the Milky Way

13/03/2026 09:44

Participants of the 1st KMOS VVVX–GalCen Spectroscopic Survey Workshop, held in December 2025 at the Institute of Astrophysics of Universidad Andrés Bello (Chile). The meeting brought together the scientific team involved in the VVV/VVVX surveys and in planning the new spectroscopic survey with the KMOS instrument at the Very Large Telescope (VLT). Credit: Dante Minniti

Astronomers began this week the first observations of a new large international survey called KMOS VVVX-GalCen Spectroscopic Survey, which will investigate tens of thousands of objects in the central region of the Milky Way. The project includes the participation of researcher Roberto K. Saito, professor at the Department of Physics at the Federal University of Santa Catarina (UFSC), the only Brazilian institution present in the main survey team.

The observations are carried out at the Very Large Telescope (VLT), one of the most advanced optical observatories in the world, located at the Cerro Paranal Observatory in the Atacama Desert, northern Chile. The telescope is operated by the European Southern Observatory (ESO).

The KMOS VVVX-GalCen is the first major spectroscopic survey led from Chile, and it was selected by ESO as one of only two large programs that will use the KMOS (K-band Multi Object Spectrograph) instrument over the next three years. In total, the project received 140 nights of observation, which corresponds to a scientific investment estimated at about 8 million dollars in telescope time.

The project is led by astronomers Matías Gómez, from Universidad Andrés Bello (Chile), and Francisco Nogueras-Lara, from the Institute of Astrophysics of Andalucía (Spain). Saito is part of the central group of researchers in the survey and is responsible for one of the scientific areas of the project.

“The first night of observations at Paranal was monitored remotely and went smoothly. Now begins the stage of analyzing the first spectra,” explains the researcher.

The observed targets were selected from two previous highly successful surveys: the VVV/VVVX, which mapped much of the Milky Way in infrared light over the past decade, and GALACTICNUCLEUS, a high-resolution survey of the innermost regions of our galaxy. The new survey will obtain spectra, a technique that allows decomposing the light of celestial objects and revealing properties such as chemical composition, temperature, and velocity.

Among the main scientific objectives are the study of rogue planets that wander freely through space, star clusters hidden by galactic dust, star-forming regions, and distant galaxies concealed behind the plane of the Milky Way. In the future, the survey is also expected to include spectroscopic observations of objects identified by the Legacy Survey of Space and Time (LSST), expanding the scientific possibilities of the project.

Learn more on the project website.

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