Recent Talks

Galaxies and the dark matter halos in which they reside are intrinsically connected. That relationship holds information about key processes in galaxy and structure formation. In this talk, I will consider how the galaxy-halo connection depends on position within the cosmic web - the familiar decomposition of large-scale structure in filaments, knots and voids. Simulations demonstrate the various ways in which the cosmic web modulates the growth and dynamics of halos. The extent to which the cosmic web impacts on galaxies is more difficult to establish. For example, galaxies might be sensitive only to the evolution of the host halo, in which case any effect of the cosmic web on galaxies is secondary, and can be inferred from the halo's history. There is evidence, however - from simulations and observations - that the cosmic web also impacts on the evolution of galaxies via the effect it has on the broader gas ecosystem in which they are embedded, as well as through "pre-processing" effects on group scale. So, how should we think of the cosmic web in its role as a transformative agent of galaxies? And what physical processes can we convincingly constrain from observations and simulations? In this talk I highlight recent work that addresses these questions.

El Telescopio Solar Europeo (EST), de clase cuatro metros, es un proyecto que se encuentra en su fase de diseño preliminar, previa a la fase de construcción. Con él se pretende aunar y mejorar las prestaciones de los actuales telescopios solares de clase un metro que están operativos. En esta charla se hará un repaso de las herramientas, diagramas, flujo de trabajo utilizado para la definición de los sistemas y subsistemas que abarca el ECS (EST Control System).

Unirse a la reunión Zoom:

https://rediris.zoom.us/j/85762975287
ID de reunión: 857 6297 5287

Youtube:

https://youtube.com/live/h8cpg5yUe9E?feature=share

I present the recent results obtained using the updated version of MG-MAMPOSSt, a code that constrains modified gravity (MG) models viable at cosmological scales using determination of galaxy cluster mass profiles with kinematics and lensing analyses. I will discuss limitations and future developments of this method in view of upcoming imaging and spectroscopic surveys, as well as the possibilities of including X-ray data to break degeneracy among model parameters. Finally I will show preliminary results about the constraints that can be obtained on the inner slope of dark matter profiles when adding the velocity dispersion of the Brightest Central Galaxy (BCG) in the dataset of MG-MAMPOSSt.

FS CMa stars are a subgroup of the B[e] stars. The forbidden emission lines and infrared excess are present in their spectra. This is a sign of very extended circumstellar region. While the B[e] phenomenon has been explained for other B[e] groups, the nature and evolutionary status of FS CMa stars has not been explained. Recently, we discovered very strong magnetic field in one of FS CMa stars, IRAS 17449+2320. The strength of the magnetic field modulus, about 6.2 kG, is in the order of the strongest Ap stars. The magnetic field together with other properties point to the post-merger origin of IRAS 17449+2320. It is very likely that other post-mergers are hidden among FS CMa stars.

The first results of our new N-body simulations show that more than half of mergers occurs in B-type stars. In other words, we are overlooking the most frequent channel of the mergers. This may have an important consequence for the enrichment of the ISM by heavier elements. Especially important it may be in the early universe.

In a time when we deal with extremely large images (be it from computer
simulations or from extremely powerful telescopes), visualizing them can
become a challenge. If we use a regular monitor, we have two options:

1) fit the image to our monitor resolution, which involves interpolation
and thus losing information and the ability to see small image details.

2) zooming in on small parts of the image to view them at full
resolution, which involves losing context and the global view of the
full image.

To alleviate these problems, display walls of hundreds of Megapixels can
be built, which allow us to visualize in full resolution small details
of the images while retaining in view a larger image context. For
example, one of the world's highest resolution tiled-displays is
Stallion (https://www.tacc.utexas.edu/vislab/stallion, at the TACC in
Texas, USA), with an impressive resolution of 597 Megapixels (an earlier
version of the system can be seen being used at
https://tinyurl.com/mt7atad9).

At the IAC we have built a more modest display wall (133 Megapixels),
which you probably have already seen in action in one of our recent
press releases (https://tinyurl.com/4bwtxvec). In this talk I will
introduce this new visualization facility (which any IAC researcher can
use) and discuss on some design issues, possible current and future
uses, limitations, etc.

Las estrellas en el cielo no están quietas. ¿Cómo podemos fotografiar el espacio sin que salgan movidas? Trípodes, monturas, sistemas de guiado y soluciones para conseguir estrellas como alfileres.

Unirse a la reunión Zoom

https://rediris.zoom.us/j/86168960971
ID de reunión: 861 6896 0971

Youtube

https://youtube.com/live/br3we052mv4?feature=share

Kepler photometry was so precise that new ways could be developed to harvest the great wealth of quasi-continuous data that has never been accessible from the ground. We initiated a project that we dubbed The Kepler Pixel Project in order to explore approaches and to discover new pulsating stars and other time-variable objects. During the project we examined individual pixels of the original Kepler mission to find interesting objects around the main Kepler targets. Specifically we launched a subproject to find background, faint RR Lyrae stars that are missing from the original Kepler sample. Altogether we found 26 new RR Lyrae stars, increasing the Kepler original RR Lyrae sample by 50%. In this talk I'll present the latest results of this project. In addition to RR Lyrae stars I will also show results on ~1000 new eclipsing binaries found in the framework of the same project.

Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) is one of the most important ground-based astronomy projects of the coming decade. In the second half of this talk I will present my research group's work on classification of variable stars with machine learning methods which is part of the Hungarian in-kind LSST contribution. The novelty of our method is that we use images of light curves, such as a human classifier would do. The method gives surprisingly good results based on the shape of light curves only, but can be further improved if additional astrophysical parameters (distance, amplitude, colors, etc.) are taken into account.

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. 

In this talk, I'll describe the full upgrade of OSIRIS at GTC telescope, once installed in the Cassegrain focal station including a new monolithic blue-sensitive detector. Changes in the standard operation of the instrument will be detailed, as well as a brief summary of the short-term instrumentation plan for GTC in 2023.

Unirse a la reunión Zoom
https://rediris.zoom.us/j/86985740449
ID de reunión: 869 8574 0449

Enlace de Youtube:

https://youtube.com/live/WxBPiiUkwJ4?feature=share