Seminars
Displaying 101 - 150 of 1222
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27/10/2022 - 12:30
SO colloquio: A new look at the torus of active galactic nuclei The classical picture to explain the observations of active galactic nuclei (AGN) required a geometrically and optically thick torus of molecular gas and dust to obscure the central engine from some lines of sight. For more than two decades, the torus was believed to be a compact (pc-scale), isolated, and rotating structure. Our recent work in the Galactic Activity, Torus, and Outflow Survey (GATOS), using ALMA and high-angular resolution mid-... Dr. Almudena Alonso Herrero |
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25/10/2022 - 12:30
SO Colloquio: Galactic Center: Radiation from black hole candidates and the dynamics of high velocity stars We summarize recent research results on the radiation mechanism of the Super Massive Black Hole (SMBH) candidate SgrA* and ask the question if there are Intermediate Mass Black Hole (IMBH) candidates in the central stellar cluster. Furthermore we give an update on the most recent high velocity stars in the central arcsecond - that are closest to SgrA*. Here we concentrate on the high velocity star cluster dynamics and on the 4711+ stars with... Prof. Andreas Eckart |
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13/10/2022 - 12:30
New developments at the IAA cosmic dust laboratory The interpretation of astronomical observations of comets and asteroids and of extrasolar objects such as protoplanetary and debris disks is crucial for understanding the origin and evolution of planetary systems. Collecting electromagnetic radiation scattered or emitted by dust particles present in these objects with powerful telescopes is often our only way to observe and characterized them. In situ observations are available for a handful of... Dr. Juan Carlos Gómez |
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06/10/2022 - 12:30
Computational Intelligence in the Big Data Context Computational Intelligence (CI) commonly refers to a variety of bio-inspired and/or human-like techniques that can be applied in optimisation, learning and modelling problems. Broadly speaking, CI comprises Artificial Neural Networks, Fuzzy Sets and Fuzzy Logic and Evolutionary Computation. In the era of big data, CI in conjunction with data mining techniques are expected to help uncover useful knowledge from big data as they are very well... Dr. Isaac Triguero |
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26/09/2022 - 12:30
The EnVision mission to Venus: Discovering why our closest neighbour is so different EnVision was selected as ESA’s 5th Medium-class mission in the Agency’s Cosmic Vision plan, targeting a launch in the early 2030s. The mission is a partnership between ESA and NASA. The primary goal is to provide a holistic view of Venus, from its inner core up to its upper atmosphere by a single mission, and will be the first mission of its kind. More specifically, EnVision will characterise Venus’ core and mantle structure, in order to study... Dr. Anne Grete Straume |
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22/09/2022 - 12:30
SO Web-loquio: Old/new problems with Active Galactic Nuclei and AGN application to cosmology After several decades of studies the basic nature of nuclear activity of galaxies is well understood. However, unexpected behaviour of AGN was already noted in the past, and with rise of the amount of data we see numerous evidences of phenomena which still require explanation, line Quasi-Periodic Ejection sources, and Changing-Look AGN. Also it is now time to address in more detail the physical nature of the simple AGN components like Broad Line... Prof. Bozena Czerny |
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21/09/2022 - 16:30
SO Webloquio: Dwarf Galaxies and the Smallest Supermassive Black Holes Despite traditional thinking, an appreciable population of (relatively small) supermassive black holes may be lurking in dwarf galaxies. Before the last decade, nearly all known supermassive black holes were in the nuclei of giant galaxies and the existence of such black holes in dwarf galaxies was highly controversial. The field has now been transformed, with a growing community of researchers working on a variety of observational studies... Dr. Amy Reines |
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16/09/2022 - 12:30
SO Colloquium: Sex and gender analysis in research and Innovation This lecture aims to increase researchers’ awareness of the current demands for the inclusion of sex and gender in their research. In fact, several governments and granting agencies, such as the European Commission and the Spanish Agencia Nacional de Investigación (AEI), now require that requests for funding address whether, and in what sense, sex and gender are relevant to the objectives and methodologies of the research proposed. Parallel with... Dr. Capitolina Díaz |
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13/09/2022 - 12:30
SO Colloquio: Studies on the origins of our solar system My goal in this colloquium is to apprehend globally the Solar System by describing a vast sample of small bodies, from Near Earth Asteroids to remote Trans-Neptunian Objects. This goes beyond projects that focused on certain populations only. The core of the talk is theoretical, with emphasis on inner structures and rings. Meanwhile, the stellar occultations by these objects will provide an exploratory route to characterize objects with widely... Dr. Bruno Sicardy |
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01/09/2022 - 12:30
SO Webloquio: Stellar Magnetism and Extra-Solar Space Weather The environment around the Sun and other late-type stars is controlled by magnetic fields. The coronal high-energy radiation (Extreme Ultra-Violet and X-ray photons), the structure and strength of stellar winds, as well as transients such as flares, coronal mass ejections (CMEs), and energetic particle events, are some examples of this magnetic influence. Apart from their direct consequences on the star and its evolution, these phenomena will... Dr. Julián Alvarado-Gómez |
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21/07/2022 - 12:30
SO Webloquio: Cold gas constraints via HI Intensity Mapping in the SKA era Intensity mapping surveys of neutral hydrogen (HI) are a new way to measure the large-scale matter distribution of our universe over a wide range of redshifts, and thus constrain cosmological parameters describing the universal expansion. The next generation of radio telescopes and interferometers - in particular the Square Kilometre Array (SKA) - are being designed and built to include optimising the detection of the HI line at low spatial... Dr. Laura Wolz |
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14/07/2022 - 12:30
A journey into the Perseus cluster of galaxies 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... Dr. Marie-Lou Gendron-Marsolais |
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07/07/2022 - 12:30
SO Webloquio: Optical interferometric studies of star and planet formation A first step towards understanding planetary formation is the characterisation of the structure and evolution of protoplanetary discs. Although the large scale disc is understood in some detail, very little is known about the inner few au. In this region, dust grains sublimate, and accretion and ejection take place, affecting the entire disk structure and evolution. In this talk, I will review how optical interferometric observations can... Dr. Rebeca García López |
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23/06/2022 - 12:30
Disks around evolved binaries: do they form second-generation planets? Most of the planets are formed around young stars. But can they also form around dying stars? The origin of the diversity and complexity of the detected exoplanetary systems stems from how they form in protoplanetary disks. These disks are intensively studied around young stars thanks to the high-angular resolution provided by recent instruments (VLT, ALMA). However, similar disks are also found around evolved stars, namely post-AGB binaries,... Dr. Jacques Kluska |
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21/06/2022 - 12:30
SO webloquio: Star-planet plasma interactions and radio emissions Exoplanets are expected to sustain various plasma interactions with their parent star, depending on the stellar and planetary magnetic field strengths and on the sub- or super-Alfvénic wind speed at the planet’s orbit. Three such interactions lead to electron acceleration and subsequent radio emissions in our solar system: magnetized planets hit by the super-Alfvénic solar wind, and the sub-Alfvénic interactions of the unmagnetized moon Io and... Dr. Philippe Zarka |
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14/06/2022 - 12:30
Detailed equilibrium and dynamical tides: impact on circularization and synchronization in open clusters Binary stars evolve into chemically-peculiar objects and are a major driver of the Galactic enrichment of heavy elements. During their evolution they undergo interactions, including tides, that circularize their orbits and synchronize stellar spins, impacting both individual systems and stellar populations. My recent work introduces an accurate implementation of equilibrium and dynamical tides in the stellar population code binary_c, relying... Dr. Giovanni Mirouh |
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09/06/2022 - 16:30
SO Webloquio: Space Weather in an Era of Innovative Science The newest generation of solar observational data is allowing a pivot toward making connections in the various solar physics domains and facilitating advanced modeling for space weather conditions and impacts. We study important physical couplings in the solar atmospheric layers, as well as connections from the solar corona through the heliosphere. To advance our understanding of how solar activity and variability impact space weather conditions... Dr. Holly Gilbert |
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07/06/2022 - 12:30
Revisiting the intermediate- to high-mass star formation Intermediate and high-mass forming stars have a large impact on the interstellar medium and nearby star forming regions. Historically, the study of the general properties of intermediate- to high-mass pre-main sequence stars has been hampered by the lack of a well-defined, homogeneous sample, and because few and mostly serendipitously discovered sources were known. As a consequence, many open problems involving high-mass star formation suffer... Dr. Miguel Vioque |
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02/06/2022 - 12:30
SO Coloquio: The Antikythera Mechanism and the Mechanical Universe The Antikythera Mechanism. An astronomical calculator and display device found in a first century BCE shipwreck, it is mechanically more sophisticated than anything known from the subsequent millennium. I want to argue that we should be showing admiration rather than amazement, and that the Mechanism fits rather well into its historic context. But this fit has major implications for the development of humanity’s view of the Universe. Prof. Michael G. Edmunds |
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31/05/2022 - 12:30
SO Webloquio: Empirical and physical properties of Lyman continuum emitters Lyman continuum emitters are galaxies showing escaping ionizing radiation, which thus contributes to ionizing the intergalactic medium. They may be the dominant source of cosmic reionization. I will present an overview of the observations and modeling of low-z analogs of the sources of cosmic reionisation recently discovered. HST observations, including UV spectroscopy with COS and rest-UV imaging with the WFC3, combined with ground-based... Dr. Daniel Schaerer |
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24/05/2022 - 12:30
Time domain astronomy with future X-ray satellites Accreting black holes emit in X-rays at the wave-band in which THESEUS will be observing (0.3 keV-20 MeV) due to their extreme physical conditions. The softer energy range is devoted to thermal emission from the accretion disc and the harder is due to the existence of a hard X-ray emitting corona (with undefined geometry so far). The importance of one component versus the other gives rise to the diverse state classification of accreting black... Dr. Maria D. Caballero-Garcia |
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23/05/2022 - 12:30
New insight into the magnetism of isolated white dwarfs Many stars evolve into magnetic white dwarfs, but we do not know when the magnetic field appears at their surface, if and how it evolves during the cooling phase, and, above all, what are the mechanisms that generate the field, and why they act on some but not all degenerate stars. Observations may help to find an answer to these questions, but their interpretation is dramatically affected by biases due to target selection and a non-homogeneous... Dr. Stefano Bagnulo |
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20/05/2022 - 11:30
Imaging the supermassive black hole at the galactic center with the EHT We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A*), the Galactic center source associated with a supermassive black hole. These observations were conducted in 2017 using a global interferometric array of eight telescopes operating at a wavelength of λ = 1.3 mm. The EHT data resolve a compact emission region with intrahour variability. A variety of imaging and modeling analyses all support an image that... José Luis Gómez, Rocco Lico, Guang-Yao Zhao, Ilje Cho, Antonio Fuentes, y Thalia Traianou |
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19/05/2022 - 12:30
SO Webloquio: Charting the first billion years of our Universe with the Square Kilometre Array The first billion years witnessed the dawn of the first galaxies, eventually culminating in the final phase change of our Universe: the Epoch of Reionization (EoR). Recent observations allowed us limited glimpses into these epochs, improving our understanding of the timing of the EoR. However, we still do not understand the first galaxies and black holes, the vast majority of which are too faint to be seen directly in the foreseeable future.... Dr. Andrei Mesinger |
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12/05/2022 - 12:30
SO Coloquio: The cloud-scale baryon cycle across the nearby galaxy population The cycling of matter in galaxies between molecular clouds, stars and feedback is a major driver of galaxy evolution. However, it remains a major challenge to derive a theory of how galaxies turn their gas into stars and how stellar feedback affects the subsequent star formation on the cloud scale, as a function of the galactic environment. Star formation in galaxies is expected to be highly dependent on the galactic structure and dynamics,... Dr. Mélanie Chevance |
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11/05/2022 - 12:30
SO Coloquio: Stellar clustering connecting the formation and evolution of galaxies to the formation and evolution of us The clustered nature of star formation leaves a long-term imprint on galaxies, stars, and planets. At young ages, stellar clustering subdivides galaxies into individual building blocks undergoing vigorous, feedback-driven life cycles that vary with the galactic environment. These units structure the interstellar medium spatially, dynamically and chemically, and collectively define how galaxies form stars. At old ages, the relics of clustered... Dr. Diederik Kruijssen |
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05/05/2022 - 12:30
Unexplored outflows in nearby low luminosity AGNs: the case of NGC 1052 NGC1052 is considered the prototype of AGN-LINERs, an AGN family at low-luminosity for which, so far, the role of outflows in their evolution has been studied the less. Thanks to MUSE and MEGARA IFS-cubes we found that the stars are distributed in a dynamically hot disc whereas the ionised gas is detected mostly in the polar direction up to 3.3 kpc. We found evidences evidence of an ionised gas outflow (jet-powered) propagating in a cocoon of... Dra. Sara Cazzoli |
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03/05/2022 - 12:30
Radio astronomy in the pre-SKA era: What can Apertif do for you? With the Square Kilometre Array still several years away, SKA pathfinder telescopes are already enabling transformational science in radio astronomy with their astounding improvements in field-of-view, sensitivity, spatial resolution, and spectral bandwidth coverage. The APERture Tile In Focus (Apertif) is one such SKA pathfinder: a phased array feed instrument upgrade to the Westerbork Synthesis Radio Telescope that increases the field-of-view... Dr Kelley Hess |
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28/04/2022 - 12:30
SO Webloquio: When artificial intelligence meets astronomy: celestial object census Over the centuries, astronomers have continued to improve the performance of telescopes and the techniques for observing and analysing data. Nowadays, humans are building more and more advanced telescopes with larger and deeper observations, reaching terabytes and even petabytes of data. The Square Kilometre Array (SKA) radio telescope, the most ambitious project in astronomy under construction, is expected to produce more than 700 petabytes of... Dr. An Tao |
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26/04/2022 - 12:30
Destroying Planetary Systems Modern astronomy invests a large amount of effort to search and characterise planetary systems around solar-like stars. In particular, at early stages of their formations in proto-planetary disks. However, we barely know much about the capacities of the planets to survive the harsh environments produced by their host stars during their evolution. In this talk, I will describe the effects a planet can produce by helping shape the mass loss of... Dr. Jesús Toala |
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21/04/2022 - 12:30
SO Coloquio: Constraints on the origin of free-floating planets from the mass function The stellar mass function is a fundamental parameter to constrain star formation models. Although the stellar content has been extensively studied since Salpeter's first work in 1955, the study of the planetary mass regime is only now becoming feasible. I will present a recent census of the Upper Scorpius and Ophiuchus star- forming region, where we identified between 70 and 170 free- floating planets. This is by far the largest sample of... Dra. Núria Miret Roig |
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20/04/2022 - 12:30
Turning Trash into Treasure: How OH megamasers are contaminating next-generation HI surveys and what they can tell us about galaxy evolution OH megamasers (OHMs) are rare, luminous masers found in (ultra-)luminous infrared galaxies ([U]LIRGs). The dominant OH masing line at 1667 MHz can spoof the 1420 MHz neutral hydrogen (HI) line in untargeted HI emission line surveys. This ambiguity creates a potential source of “contamination” in HI surveys, particularly for next-generation surveys that will reach groundbreaking sensitivities and redshifts. In this talk, I will present... Dr. Hayley Roberts |
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07/04/2022 - 13:00
SO Webloquio: Measuring the Magnetic Fields of Exoplanets with Star-Planet Interactions Planets interact with their host stars through gravity, radiation and magnetic fields. For giant planets orbiting stars within ~20 stellar radii (=0.1 AU for a Sun-like star), magnetic star-planet interactions (SPI) are observable at a range of wavelengths with a variety of photometric, spectroscopic and spectropolarimetric techniques. At such close distances, planets orbit within the sub-alfvénic radius of the star, where magnetic interactions... Dr. Evgenya Shkolnik |
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31/03/2022 - 12:30
How the intracluster light is going to change your life! There are a huge number of astrophysical phenomena that remain barely studied due to the lack of large, multiwavelength and deep optical surveys. This is the Universe with the lowest density of stars, largely unseen by past large field surveys like the Sloan Digital Sky Survey (SDSS). For instance, only a handful of galaxy clusters have been observed with enough depth to witness the intracluster light (ICL), made up of stars that drift freely... Dr. Mireia Montes |
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24/03/2022 - 12:30
Is it possible to simulate time machines in a laboratory? General Relativity is the most succesful theory we have for describing gravitational phenomena. Its range of applicability is vast: from solar system scales to cosmological scales. It is well-known that GR allows the existence of time machines: devices that are able to generate Closed-Timelike-Curves (CTCs). Although these kind of objects are allowed in GR, most researchers believe that they cannot occur on macroscopic scales. However, it is... Gerardo Garcia |
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17/03/2022 - 12:30
Surprises from MAVEN at Mars: Aurora, meteor showers, and a new water loss paradigm The Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft carries the Imaging Ultraviolet Spectrograph (IUVS) to study the Mars atmosphere and atmospheric escape. After more than two Mars years in orbit, IUVS has gained new insights on key phenomena at Mars including dayglow, nightglow, aurora, meteor showers, clouds, solar-planetary interactions and atmospheric evolution. In this presentation, I will highlight three key results... Dr. Nick Schneider |
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10/03/2022 - 12:30
The RoboPol Program: Optical Polarimetric Monitoring of Blazars Blazars are a subclass of Active Galactic Nuclei with relativistic jets pointing at us. For this reason the highly amplified polarized synchrotron emission from their jets dominates in the optical band. Typically, the electric vector position angle (EVPA) of the optical polarized emission in blazars varies in an erratic way. However, in rare cases the EVPA displays long, smooth and monotonic rotations. Being puzzled by this phenomenon missing a... Dr. Dimitriy Blinov |
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03/03/2022 - 12:30
The continuous rise of bulges out of galactic disks A tantalizing enigma in extragalactic astronomy concerns the chronology and driving mechanisms of the buildup of the central luminosity excess (bulge) in spiral galaxies like our Milky Way, i.e. in systems referred to as late-type galaxies (LTGs) in the Hubble classification scheme. The standard scenario envisages a two-phase galaxy formation process, with the bulge assembling first in a quick and violent quasi-monolithic episode, with the disk... Dr. Iris Breda |
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24/02/2022 - 12:30
SO Webloquio: Exploring the transient radio sky with the SKA and its precursors Radio astronomical observations probe particle acceleration in some of the most extreme environments in the Universe. For example, we can trace the relativistic jets produced by accreting black holes; observe flashes from hyper-magnetised neutron stars; and study the aftermath of stars that are ripped to shreds as they pass close to super-massive black holes. These events provide critical information about the extremes of the Universe, but they... Dr Jason Hessels |
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17/02/2022 - 12:30
The Africa Millimetre Telescope project - extending the EHT The Africa Millimetre Telescope (AMT) project led by the Radboud University and the University of Namibia aims to realise a new telescope on the Gamsberg mountain in Namibia to extend the existing network of telescopes that together form the EventHorizonTelescope (EHT). For the future of the EHT more independent nodes in the network are needed to increase the overal redundancy of the network and to improve the image quality and allow for time-... Dr. Marc Klein Wolt |
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10/02/2022 - 12:30
A high-fidelity sky mock of DESI galaxies in the LCDM cosmology By using N-body simulations in which different cosmologies have been assumed and by comparing them with large-scale galaxy surveys, we can constrain cosmological parameters, even ruling out some cosmological models. In this talk I will describe how we use the Uchuu simulation for this purpose. Uchuu is an N-body dark matter simulation that has been created by an international team of researchers from Japan, Spain, USA, Argentina, Australia,... Julia Ereza |
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03/02/2022 - 12:30
SO Webloquio: The Milky Way's young substellar population Young clusters and star forming regions are home to a large number of substellar objects with masses below the hydrogen-burning limit at 0.075 MSun. Most of our knowledge about their populations comes from nearby regions (d lower 400 pc), where we find consistent formation rates of 2-5 young brown dwarfs per 10 newborn stars. Brown dwarf theories, on the other hand, predict that high gas or stellar densities, as well as the presence of massive... Dra Koraljka Muzic |
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27/01/2022 - 12:30
La IAU más cerca que nunca The International Astronomical Union (IAU) has more that 13000 members. Each country pays according to a table that has to do with the number of people belongin to the IAU. But the IAU is not only a club of members but has a number of activities that are open to every member. In particular the IAU run 9 Symposia per year with topics relevant to current astrophysics. On years where there are a General Assembly on top of the 9 Symposia the IAU... Dr. José Miguel Rodriguez Espinoza |
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25/01/2022 - 12:30
Cosmological QUOKKAS: Proof of concept and early results on the Hubble Constant tension Distances are one of the most important yet difficult to get quantities in astronomy. Normally, astronomers use redshifts (which are relatively easy to measure) as distance measure, but this only works if one assumes that there is a relationship between redshift and distance. The relationship between redshift and distance was first observationally verified in the 1920s by Edwin Hubble. He found that the further away a galaxy was, the galaxy... Dr. Jeff Hodgson |
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20/01/2022 - 12:30
Astronomy for attaining sustainable development goals in Africa Education and its contribution to science, technology, and innovation are the key points for combating poverty in the long term. Education is also a key point for empowering girls and women, which is fundamental for achieving the United Nations Sustainable Development Goals (SDGs). Astronomy is a powerful tool to promote education and science but, in addition to that, it is also one of the leading sciences for bringing strong technological... Dra. Mirjana Povic |
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13/01/2022 - 12:30
Galaxy morphologies in multi-wavelength surveys In this talk I will present novel results obtained by using a combination of broad and narrow band optical photometry, from the J-PAS and S-PLUS surveys, in the determination and study galaxy of galaxies’ morphologies. In particular we used Morfometrika and GALFITM to recover non-parametric and parametric values to characterize galaxies’ shapes, as well as a deep learning method for the S-PLUS survey to classify galaxies into early and late type... Dra. Arianna Cortesi |
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11/01/2022 - 12:30
SO Webloquio: Active Galactic Nuclei as seen from the 7 X-ray eyes of eROSITA Active Galactic Nuclei (AGN) are not longer considered part of a small and exotic source population but are now widely accepted to play a significant role in the evolution of galaxies through cosmic time. However, even 20 years after the realization of the close link between the galaxies and the active SMBH that they host, the various mechanisms and the interconnection are not fully clear. Two complementary approaches are followed to deepen our... Dra. Mara Salvato |
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16/12/2021 - 12:30
Lighthouse Piercing Through the Storm Clouds in Massive Star Formation Massive stars play crucial roles in determining the physical and chemical evolution of galaxies. They shape their environment from early in their protostellar phase when they blast the surrounding with powerful jets, up until their violent deaths in the form of supernova. However, they form deeply embedded in their parental clouds, making it challenging to directly observe these stars and immediate environments. Notwithstanding, their massive... Dr Ruben Fedriani |
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09/12/2021 - 12:30
SO Webloquio: Unveiling the unseen magnetized universe with MeerKAT Galaxy clusters are known to harbour magnetic fields, the nature of which remains unresolved. Intra-cluster magnetic fields can be observed at the density contact discontinuity formed by cool and dense plasma running into hot ambient plasma, and the discontinuity exists near the second brightest galaxy, MRC0600-399, in the merging galaxy cluster Abell 3376 (redshift 0.0461). Elongated X-ray emission in the east–west direction shows a comet-like... Dr. James Chibueze |
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02/12/2021 - 12:30
The PUMA project. Mergers and feedback in local ULIRGs resolved by ALMA and MUSE+AO Galaxy mergers and interactions have a key role in the evolution of galaxies, specially at high-z when they were more common than today. Mergers trigger starbursts and AGN activity, which are both regulated by negative feedback processes, as well as can turn spiral galaxies into massive quiescent objects. The local counterparts of these major interactions and mergers are local ULIRGs (L(IR)/Lsun > 1e12) which, thanks to their proximity, allow... Dr. Miguel Pereira Santaella |