Found 10 talks width keyword hydrodynamics
We present the extended data release of the Calar Alto Legacy Integral Field Area (CALIFA) survey (eDR). It comprises science-grade quality data for 895 galaxies obtained with the PMAS/PPak instrument at the 3.5 m telescope at the Calar Alto Observatory along the last 12 years, using the V500 setup (3700-7500Å, 6Å/FWHM) and the CALIFA observing strategy. It includes galaxies of any morphological type, star-formation stage, a wide range of stellar masses ( ∼10^7-10^12 Msun), at an average redshift of ∼0.015 (90\% within 0.005 < z <0.05). Primarily selected based on the projected size and apparent magnitude, we demonstrate that it can be volume corrected resulting in a statistically limited but representative sample of the population of galaxies in the nearby Universe. All the data were homogeneously re-reduced, introducing a set of modifications to the previous reduction. The most relevant is the development and implementation of a new cube-reconstruction algorithm that provides an (almost) seeing-limited spatial resolution (FWHM PSF ∼1.0"). Furthermore we present the analysis performed using the pyPipe3D pipeline for these dataset. We include a description of (i) the analysis performed by the pipeline, (ii) the adopted datamodel for the derived spatially resolved properties and (iii) the catalog of integrated, characteristics and slope of the radial gradients for a set of observational and physical parameters derived for each galaxy. All these data has been distributed through the following webpage: http://ifs.astroscu.unam.mx/CALIFA_WEB/public_html/
Understanding stellar structure and evolution significantly impacts our understanding of the tight-knit evolution of galaxies and exoplanet systems. However, hidden behind the luminous layers of the stellar atmosphere, the deep interior of a star is eluding from direct measurements. The seismic study of waves propagating the deep interior provides the only way to measure the internal structure, dynamics, and mixing in any given star and compare it to theoretical models.
With the photometric data from space missions, such as the NASA Kepler telescope, a golden age has begun for seismology. In particular, the seismic studies of thousands of solar-like have led to numerous breakthroughs in our understanding of the stellar structure of red-giant stars. Complimentary information on stellar binarity, tidal forces, rotation, and lithium abundance provide additional constraints to characterize the advanced evolution of stars further and provide high-resolution insights into complex internal adjustments. Approaching a sample of ~1000 identified solar-like oscillators in binary systems, provided by the ESA Gaia and NASA TESS missions draws an exciting picture on the interaction of stellar and orbital evolution.
ID de reunión: 892 7515 0368
Código de acceso: 101169
I present a detailed analysis of the scaling relations of ETGs and suggest a way to predict the evolution of the distributions of galaxies in these planes. This new approach is able to account of several features observed in the FP projections and of the tilt of the Fundamental Plane.
Vimos Public Extragalactic Redshift Survey (VIPERS) is a spectroscopic survey designed to investigate the spatial distribution of ~90k galaxies on redshift 0.4<z<1.2. The catalogue of spectroscopic observations, combined with auxiliary photometric data, is perfect for evolutionary studies of different types of galaxies. But also for tracing rare objects. One of them are the so-called “red nuggets”, progenitors of the most massive galaxies in the local Universe. The discovery of red nuggets - highly massive, passive and extremely compact galaxies - at high redshift challenged the leading cosmological models, as they do not fit into the evolutionary paths of passive galaxies. Taking into account that the galaxies' mergers are stochastic events, it is possible that some red nuggets remain relatively unaltered for billions of years. Those survivors constitute a group of unique galaxies in the local Universe, commonly named “relics”. Despite numerous studies dedicated to red nuggets and relics, the link between the population of compact, massive, passive galaxies in the early Universe and their remnants in the local Universe, is still poorly understood.
In my talk I will present the first spectroscopically selected catalogue of red nuggets at the intermediate redshift. It is the most extensive catalogue of this kind of galaxies above redshift z > 0.5. Selected under the most strict criteria, the group of 77 objects consists of a statistically important sample, which allows for analysis of physical properties of those rare passive giants. I will discuss the influence of compactness criteria on the sample size. Moreover I will present VIPERS red nuggets number densities and discuss the environmental preferences of those exceptional galaxies.
Mathematics of atmospheric fronts: S.Q.G.(Surface Quasigeostrophic Equation) is a relevant model to understand the evolution of atmospheric fronts. It represents also a mathematical challenge, because of its non-linear and non-local character, which illustrates the rôle of mathematics in the development of science.
This colloquium will be held in person in the Aula
In the local universe most of the stellar mass is in passive galaxies, where star formation is
absent or at very low levels. Understanding what are the mechanisms that have been
responsible for quenching star formation in galaxies, and transforming them into passive,
quiescent systems, is one of the main observational and theoretical challenges of extragalactic
astrophysics. I will give a brief overview of the several possible quenching causes and physical
processes that have been proposed so far, ranging from feedback from black hole accretion and
starburst activity, to effects associated with the large scale environment in which galaxies live.
Although most of these mechanisms and causes play a role in different classes of galaxies and
at different epochs, multi-band observations are providing growing evidences that just a few of
them play the key, dominant role.
I will conclude by providing prospects for further investigating these aspects and tackling open
questions with the next generation of observing facilities.
This talk will be dedicated to luminous (LBol~1E47 erg/s),
high-redshift quasars, which are ideal targets to investigate (i) feedback
from SMBHs, and (ii) the early growth phases of giant galaxies. I will
present evidence of SMBH-driven outflows at all Cosmic epochs, back to
the early Universe. These outflows involve all gas phases (molecular,
neutral, ionised) and extend on nuclear to galactic and circum-galactic
scales. I will report on the first systematic study of the molecular gas
properties in the host-galaxies of the most luminous quasars, fundamental
to probe the impact of SMBH feedback on the host-galaxy evolution. I will
show that luminous quasars pinpoint high-density sites where giant galaxies
assemble, and I will discuss the major contribution of mergers to the final
galaxy mass. To this aim, I will present a wealth of multi-wavelength (UV
to sub-millimeter) observations from the WISE/SDSS hyper-luminous quasars
survey at z~2-5 (WISSH), and recent results from the ESO large program
XQR-30, the Ultimate X-SHOOTER Legacy Survey of Quasars at the Reionization
(This seminar is organized by the IAU G5 commission on stellar and planetary atmospheres)
Task-based computing is a method where computational problems are split
into a large number of semi-independent tasks (cf.
2018MNRAS.477..624N). The method is a general one, with application not
limited to traditional grid-based simulations; it can be applied with
advantages also to particle-based and hybrid simulations, which involve
both particles and fields. The main advantages emerge when doing
simulations of very complex and / or multi-scale systems, where the
cost of updating is very unevenly distributed in space, with perhaps
large volumes with very low update cost and small but important regions
with large update costs.
Possible applications in the context of stellar atmospheres include
modelling that covers large scales, such as whole active regions on the
Sun or even the entire Sun, while at the same time allows resolving
small-scale details in the photosphere, chromosphere, and corona. In
the context of planetary atmospheres, models of pebble-accreting hot
primordial atmospheres that cover all scales, from the surfaces of
Mars- and Earth-size embryos to the scale heights of the surrounding
protoplanetary disks, have already been computed (2018MNRAS.479.5136P,
2019MNRAS.482L.107P), and one can envision a number of applications
where the task-based computing advantage is leveraged, for example to
selectively do the detailed chemistry necessary to treat atmospheres
saturated with evaporated solids, or to do complex cloud chemistry
combined with 3-D radiative transfer.
In the talk I will give a quick overview of the principles behind
task-based computing, and then use both already published and still
on-going work to illustrate how this may be used in practice. I will
finish by discussing how these methods could be applied with great
advantage to problems such as non-equilibrium ionization, non-LTE
radiative transfer, and partial redistribution diagnostics of spectral
AbstractThe amount of baryons seen in the local Universe falls short by a factor2-5 if compared to the amount of detected baryons at intermediate (z~2)or high (z~1,100) redshift. This is the so called "missing baryon" problem in Cosmology. Hydrodynamical simulations of the large scale structure predict that most of those missing baryons should be in the form of ionized gas present in slightly overdense regions, at a temperature ranging from 10^5 to 10^7 K, conforming the "Warm Hot Intergalactic Medium" (WHIM). This WHIM would not form stars, and would not emit or absorb either in the IR, optical or UV. However, it should interact with the photons of the Cosmic Microwave Background (CMB) through two different channels: (i) Thompson scattering (where there is no energy exchange) and (ii) Compton scattering (where hot electrons transfer energy to the CMB photons, distorting their black body spectrum). I shall review the status of the search for missing baryons in the context of CMB observations and the currently most favored cosmological model. I shall also outline new methods and prospects for detecting this missing gas with upcoming CMB experiments and address the link between the cosmic baryon problem and the search for (so far undetected) bulk flows at scales of ~10 Mpc/h.
AbstractIn the EU funded Marie Curie Excellence Team CIFIST (Cosmological Impact of the FIrst STars) work is under way to construct 3D radiation-hydrodynamical model atmospheres for late-type dwarfs and giants, in particular of low metallicity. I will present an overview of the present state of the efforts, discuss some applications of the models, and point to necessary future developments.
« Newer Older »
- TBDThursday December 14, 2023 - 10:30 GMT (Aula)
- GESCOPThursday January 18, 2024 - 10:30 GMT (Aula)