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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

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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Evento aberto à toda a comunidade da UFSC

Aula magna 2026
Ciclo de seminários do programa de pós-graduação em Física da UFSC
Data e horário: 13/03/2026 às 10h15
Local: Auditório da Física (FSC 212)

Por que falar sobre Ciência Aberta para a comunidade da Física
Débora Peres Menezes
Diretora de Avaliação de Resultados e Soluções Digitais – CNPq
Profª. Titular – Depto de Física – Universidade Federal de Santa Catarina

A Ciência Aberta tem ganhado destaque como um modelo promissor para democratizar o acesso ao conhecimento científico e fomentar a inovação. No entanto, sua aplicação no Brasil requer uma análise criteriosa das condições de trabalho dos pesquisadores, dos custos associados à sua implementação e da necessidade de regulamentação em âmbito federal. Infelizmente, parte da discussão correu à revelia da comunidade científica nos últimos anos, tendo se concentrado nos órgãos de fomento, órgãos de controle e áreas específicas. Pretendo abordar os seguintes pontos:

• A importância da Ciência Aberta como uma iniciativa global e sua relevância para o Brasil;
• As condições estruturais e financeiras que impactam os pesquisadores no país, em especial, os físicos;
• O papel da regulamentação federal na garantia de sua aplicação responsável e eficiente;
• Os desafios da Economia do Conhecimento que envolve o colonialismo de dados, com destaque para os possíveis impactos na soberania nacional relacionados à ampla disponibilização de dados obtidos em pesquisas feitas com financiamento público.