Found 32 talks width keyword galactic structure
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/
Finally, I will summarise our ongoing JWST work within the GATOS (Galactic Activity, Torus and Outflow Survey) collaboration. In particular, I will focus on our recent study about the survival of PAH molecules in AGN-driven outflows.
Only recently, thanks to the Gaia, have we been able to directly measure how our own Galaxy was formed since its infancy, by cannibalizing smaller galaxies formed at the core of dark matter subhalos. These accretion events can be seen as kinematic groups and may have brought their own group of globular clusters, some of which are only seen today as their remnant cold stellar streams. Here I will discuss how the main accretion events unveiled by Gaia can be linked to previously known halo substructures, mainly large stellar clouds identified more than a decade ago in large photometric surveys. Additionally I will discuss the Jhelum stellar stream in the light of its interaction with the Sagittarius stream, which can give us insight on the details of this ongoing accretion event. Finally, I will briefly discuss how the new Gaia XP DR3 spectra is aiding in the identification of metal-poor unmixed halo substructures in the solar neighbourhood, highlighting the case of ED-2, a [Fe/H] = -2.5 cold stellar stream in which the Sun is embedded in.
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.
Within the hierarchical framework for galaxy formation, merging and
tidal interactions are expected to shape large galaxies up to the
present day. While major mergers are quite rare at present, minor
mergers and satellite disruptions - that result in stellar streams -
should be common, and are indeed seen in the stellar halos of the Milky
Way and the Andromeda galaxy. In the last years, the Stellar Stream
Legacy Survey (PI. Martinez-Delgado) has exploited available deep
imaging of some nearby spiral galaxies with the ultimate aim of
estimating the frequency, morphology and stellar luminosity/mass
distribution of these structures in the local Universe. In this talk, I
will present the first results of our systematic survey of stellar
streams together with some recent follow-up observations (e.g. Megara,
Subaru) and N-body modelling of the most striking streams. Finally,
I will discuss what we can learn about galaxy formation from the results
of this survey, including the comparison with the available L-CDM
cosmological simulations, and our plans to extend this stream survey
at lower surface brightness regime with the recently approved ARRAKHIS,
the first ESA fast-mission lead by Spain.
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.
Gravitational dynamical friction affecting the orbits of globular clusters (GCs) was studied extensively as a possible formation mechanism for nuclear star clusters in galaxies. In well-known examples that showcase this phenomenon, like the Milky Way and M31 galaxies, the medium which affects the dynamical friction is dominated by bulge stars. In comparison, the case for dynamical friction in dark matter-dominated systems is much less clear. A puzzling example is the Fornax dwarf galaxy, where the observed positions of GCs have long been suspected to pose a challenge for dark matter, dynamical friction theory, or both. We search for additional systems that are dark matter-dominated and contain a rich population of GCs, offering a test of the mechanism. A possible example is the ultra diffuse galaxy NGC5846-UDG1: we show that GC photometry in this galaxy provide evidence for the imprint of dynamical friction, visible via mass segregation. If confirmed by future analyses of more GC-rich UDG systems, these observations could provide a novel perspective on the nature of dark matter.
The formation and evolution of galaxies across cosmic time proceeds in different phases, paced by their internal evolution and external factors like gas accretion and mergers. The complex and always changing interplay between these mechanisms drives the assembly of galaxies and the physical conditions for star formation, which leaves observable imprints on the stellar populations. Large astrometric and spectroscopic surveys (e.g. Gaia, APOGEE, GALAH) collect the signatures of these past events in the building history of the Milky Way. However, simulations and models are necessary to decode the data. In this talk, I will present results from a series of hydrodynamical simulations of Milky Way-like galaxies, both in isolation and in cosmological context using the VINTERGATAN simulation. I will show the crucial role of mergers, and of the end of the merger phase, in forming the thick and thin Galactic discs, and making the transition between the two. I will then nuance this conclusion by explaining why the secular consumption of gas enables a similar transition, as well as the emergence of spirals, without any external factors.
Stellar populations vary across the galaxy population. However, even within a single galaxy, there are stellar population gradients which spatially resolved spectroscopic studies are beginning to reveal. The MaNGA survey permits a study of gradients in a sample of early-type galaxies which is nearly two orders of magnitude larger than previous work. This allows us to quantify the effects of gradients on estimates of the stellar and dynamical masses of these galaxies, and to study how age and abundance gradients, and thus star formation and assembly histories, vary across the population. In this talk I will present results from our recent analysis.
zoom link: https://rediris.zoom.us/j/97614680345
« Newer 1 | 2 | 3 | 4 Older » Last >>
- Globular clusters as tracers of the Milky Way assembly historyDr. Davide MassariThursday October 5, 2023 - 10:30 GMT+1 (Aula)
- CONCERTO: a breakthrough in the wide field-of-view spectroscopy at millimeter wavelengthsDr. Alessandro FassanoTuesday October 10, 2023 - 12:30 GMT+1 (Aula)