Recent Talks

We present a sample of 734 ultracool dwarfs using LAMOST DR7 spectra, i.e.,  those having a spectral type of or later than M6, including an L0.  All of these red or brown dwarfs are within 360 pc, with a Gaia G magnitude brighter than 19.2 mag, a BP-RP color redder than 2.5 mag  and an absolute G magnitude fainter than 9 mag. Their stellar parameters  (Teff, log g, and [M/H]) are consistent with being the Galactic thin-disk  population, which is further supported by their kinematics using LAMOST radial velocity plus Gaia proper motion and parallax.  A total of 77 are detected  with the lithium absorption line at 6708 A, signifying youth and substellar nature. We report on their kinematic ages estimated by the velocity dispersion. Thirty five close pairs are identified, of which the binarity of six is discovered for the first time.

With the aim of detecting cosmological gas accretion onto galaxies of the local Universe, we examined the Ha emission in the halo of the 164 galaxies in the field of view of MUSE-Wide (Urrutia+19) with observable Ha (redshift < 0.42).  An exhaustive screening of the Ha images led us to select 118 reliable Ha emitting gas clouds. To our surprise, around 38 % of the time the Ha line profile shows a double peak centered at the rest-frame of the corresponding galaxy. We have explored several physical scenarios to explain this Ha emission, among which accretion disks around rogue  intermediate mass black holes (IMBHs) fit the observations best. I will describe the data analysis (to discard, e.g, instrumental artifacts and high redshift interlopers), the properties of the Ha emitting clumps (their fluxes, peak separation, and spatial distribution with respect to the central galaxy), and the arguments leading to the IMBH hypothesis rather than other alternatives (e.g., cosmological gas, expanding bubbles, or shocks in the circum galactic medium).

Zoom Link:

https://rediris.zoom.us/j/84163489744?pwd=bd4IPA6tcZmVDXa0eYOODcAmnWgTRd.1

Meeting ID: 841 6348 9744

Passcode: 829227

https://youtu.be/cLZXeAfDTvQ

EST será un telescopio solar de clase 4-metros que se instalará en La Palma. Dos son las principales diferencias respecto a otros telescopios de tamaño similar: al trabajar a cúpula abierta está completamente sometido a las fuerzas producidas por el viento, y al ser solar recibirá una gran cantidad de radicación térmica que debe ser debidamente gestionada. En esta charla se presentarán los estudios preliminares realizados para la selección la solución técnica más prometedora para el M1 Assembly, así como unas pinceladas sobre el diseño preliminar que se está desarrollando a partir de ese concepto.

https://youtu.be/n_DA63bXK0A

The first part of this talk will present an overview of the tool "module" and its main commands and flags. "module" provides the dynamic modification of the user’s environment for supporting multiple versions of an application or a library without any conflict. In the second part, we’ll first explain what Python virtual environments are, and describe three actual cases in which they are used. We’ll then illustrate a practical example to install a Python virtual environment, and duplicate it on a different platform.

El Telescopio Solar Europeo (EST) se encuentra actualmente en la fase de diseño preliminar. Uno de los principales objetivos de esta etapa es identificar y definir los requisitos técnicos que guiarán su desarrollo y posterior construcción. En este sentido, las herramientas de modelado y simulación constituyen un elemento clave para la caracterización de prestaciones y la evaluación de distintas alternativas técnicas. El objetivo de esta charla es presentar algunos de los modelos desarrollados por la Oficina de Proyectos de EST para la evaluación de los requisitos dinámicos del telescopio. En concreto, se profundizará en el modelo mecatrónico diseñado para el control del movimiento de los ejes de la estructura.

El seminario se impartirá en el Aula y se anima encarecidamente a asistir presencialmente. Habrá café tecnológico tras la charla, a las 11h30 en la cafetería.

Unirse a la reunión Zoom:
https://rediris.zoom.us/j/87861451633

Enlace de Youtube:

https://youtu.be/uCTyZVr76dc

In the 16th SMACK, the very basics of LaTeX were introduced; showing how to make a basic document from scratch, set the printable size, inserting images and tables and etc. In this session, we will go into more advanced features that are also commonly helpful when preparing a professional document (while letting you focus on your exciting scientific discovery, and not have to worry about the style of the output). These features include automatically referencing different parts of your document using labels (this allows you to easily shuffle figures, sections or tables), making all references to various parts of your text click-able (greatly simplifying things for your readers), using Macros (to avoid repetition or importing your analysis results automatically), adding bibliography, keeping your LaTeX source, and your top directory clean, and finally using Make to easily automate the production of your document.

Lecture notes: https://gitlab.com/makhlaghi/smack-talks-iac/-/blob/master/smack-17-latex-b.md

FastCam is an instrument designed to obtain high spatial resolution images in the optical wavelength range from ground-based telescopes by using the Lucky Imaging technique. This technique is based on the idea of registering the instants of atmospheric stability, typically lasting just some milliseconds, using very short exposures. The instrument consists of a very low noise and very fast readout speed EMCCD camera capable of reaching the diffraction limit of medium-sized telescopes from 380 to 1000 nm. At the beginning of 2019, a new camera was commissioned. Now the instrument makes use of an Andor iXon DU-888U3-CSO#BV back-illuminated system containing a 1024x1024 pixel frame transfer CCD sensor from E2V Technologies. The pixel size is 13 microns and the camera allows up to 30 exposures per second. A new update of the camera acquisition software is currently being worked on. A complete characterisation of the detector is also being carried out in order to better understand and exploit all the performances of the instrument, applying particular configurations for each scientific case. A standard reduction of the data is also being implemented in order to offer it to all users of the instrument. The first FastCam was an instrument jointly developed by the Spanish Instituto de Astrofísica de Canarias (IAC) and the Universidad Politécnica de Cartagena which started in 2006. Since then, the IAC assumed the instrument and tested it on several telescopes of the OOCC, among them the Nordic Telescope (NOT) where images were obtained in the optical domain diffraction-limited with high contrast, reaching a resolution of 0.1”/px. Currently FastCam is a common-user instrument at the Cassegrain focus of the 1.52-meter Carlos Sánchez Telescope (TCS, Teide Observatory) where observations are being made to calibrate the detector with sky tests. The idea is that in the near future it will be installed in the NOT to finish the commissioning process of the new camera and the whole acquisition system so that this instrument can be used by the international community.