Recent Talks

El Instituto de Astrofísica de Canarias ha llevado a cabo la adquisición, instalación y calibración de diversas máquinas de fabricación óptica, con el objetivo de consolidarse como proveedor autosuficiente bajo la denominación de Centro de Sistemas Ópticos Avanzados (CSOA).

Para este propósito, se dispone de dos laboratorios diferenciados. El primero, orientado a óptica de pequeño tamaño, con diámetros inferiores a 500 mm, que cuenta con equipamiento para desbaste, pulido, ultrapulido y recubrimientos. El segundo laboratorio está destinado a óptica de gran tamaño, con diámetros de hasta 1500 mm, y está equipado con maquinaria de pulido y recubrimientos.

En la presente comunicación se describe el laboratorio de fabricación de óptica de pequeño tamaño, el cual integra todos los sistemas necesarios para la fabricación completa de elementos ópticos, abarcando todas las etapas del proceso, desde el corte del bloque óptico hasta el ultrapulido mediante técnicas de ion beam figuring. Se presentará una descripción detallada de las máquinas empleadas y de sus capacidades operativas. Asimismo, se abordan los materiales ópticos procesados, los ensayos de caracterización realizados y las metodologías de medida aplicadas. Finalmente, se expodrán las líneas de trabajo actuales y los objetivos estratégicos a largo plazo en la fabricación de óptica con diámetros de hasta 500 mm.

Asteroids preserve key records of the Solar System’s history, providing insights into collisional and surface evolution as well as the origins of water and life on Earth. Among them, Near-Earth Asteroids (NEAs), with perihelion distances smaller than 1.3 au, represent a unique population that enables detailed investigations of the secular evolution of their orbits and spin states. They are also crucial targets for future spacecraft exploration, planetary defense, and potential space resource utilization. In this talk, I will introduce recent observational studies of NEAs conducted during close approaches to Earth within a few lunar distances, where otherwise impossible observations become feasible. These include simultaneous tricolor video photometry of sub-minute rotators, as well as archival-data studies of an asteroid that will soon approach Earth closely enough to become a spatially resolved target.

B-type stars have temperatures ranging from 10000 to 30000 Kelvin and masses between 3 and 20 Mo. They exhibit radiation-driven stellar winds that lead to significant mass loss throughout their evolution, influencing the chemical enrichment of the interstellar medium. A key feature of this stellar group is its high degree of heterogeneity, including a wide variety of peculiar objects such as stars with high rotational velocities, circumstellar envelopes, or chemical anomalies (e.g., Be, B[e], HAeBe, and LBVs). In these cases, determining fundamental parameters like effective temperature (Teff)  and surface gravity (logg) is particularly challenging, as both line intensities and profiles can be strongly affected by circumstellar material or rotation.

An alternative and robust methodology for estimating these parameters is the BCD (Barbier-Chalonge-Divan) Spectrophotometric Classification System. Based on the analysis of the Balmer discontinuity (or Balmer jump) at 3700 Å, this method was developed as a quantitative equivalent to the MK and Yerkes systems using measurable observable parameters. The BCD system offers a straightforward approach to determining Teff and logg, even in stars with prominent emission lines, while also providing independent estimates of color excess and distance.

In this seminar, I will discuss the application of the BCD method to a diverse sample of objects, ranging from B-type stars in open clusters to emission-line stars and objects in transitional evolutionary phases, such as sgB[e], LBV, and HAeBe stars.

En esta presentación se describe una solución de despliegue para el acceso remoto y autenticado a aplicaciones gráficas mediante navegador web, sin necesidad de instalar software adicional en el cliente. Inicialmente desarrollada en el contexto del proyecto TTNN, se plantea como una propuesta reutilizable para distintos sistemas instrumentales, como aplicaciones de control de instrumentos o telescopios.

 La solución es aplicable a cualquier aplicación gráfica que se ejecute en un host con servidor VNC y conectividad IP, sin requerir modificaciones en la propia aplicación. Asimismo, incorpora mecanismos de gestión de usuarios, autenticación y configuración flexible de las conexiones.

El despliegue se basa en la utilización de servidores VNC en las máquinas del sistema y en Apache Guacamole como plataforma de gestión y provisión del acceso remoto.

The implementation of Adaptive Optics at the GTC, combined with the science instrument FRIDA -- an imager and integral field spectrograph operating in the near-infrared —- represents a factor of 10 to 15 improvement in angular resolution compared to current or planned GTC instruments. These resolutions are still a factor of 1.5 to 4 better than those achieved by the finest space telescopes, JWST and HST. This presentation highlights the imminent realisation of these capabilities at the GTC and the unique scientific opportunities enabled by the GTC+AO+FRIDA combination. To this end, I will outline possible science pathways that are uniquely possible with GTC+AO+FRIDA, ranging from stellar surface mapping to studies of the Local Group at the finest spatial scales and the high-redshift Universe.

"MECHANISM 4.0: Actualización y mejora del software de control de dispositivos del banco MCAO". Por Eric Ríos Hamilton.
"Desarrollos varios para el nuevo software de control de los Telescopios Nocturnos". Por Óscar Guerra Rodríguez.

The aim of this presentation is to introduce the research I have carried out in recent years, which led to being awarded a Ramón y Cajal fellowship, and to outline the future goals of the project. I will cover the three main pillars of my work: the analysis of spectropolarimetric observations, the use and development of inversion codes (computational tools used to infer the physical parameters of the solar atmosphere from these observations), and the design of state-of-the-art instrumentation for ground-based, balloon-borne, and space telescopes. All of these efforts serve a common purpose: advancing our understanding of the Sun. Thus, I will also touch on some of the most compelling open questions in solar physics I have worked on, including the nature of quiet Sun magnetism and the energy release mechanisms behind solar flares.

Wide-field optical imaging is fundamental to nearly every area of astronomy and astrophysics at all wavelengths, particles, and gravitational waves and are the highest demand instruments on their respective telescopes. We have entered the era of billion-dollar 'mega-facilities', such as the James Webb, Roman, and Euclid Space Telescopes, the Cherenkov Telescope Array, the ESO ELT, Giant Magellan Telescope, and Thirty Meter Telescope, the Square Kilometre Array, KM3Net, LIGO/Virgo/KAGRA and future gravitational wave detectors, among others. These facilities require deep, 8m-class wide-field optical imaging to help achieve their main science objectives, obtain deep, accurate photometric redshifts, localise sources and identify and study their host galaxies, and answer long-standing questions. However, existing 8m-class wide-field imagers do not have several much-needed wide-field optical capabilities, and no such imagers are planned on Earth or in space for the next 2+ decades. These capabilities include very deep (m ~ 28-30) u-band and 3000A-10000A imaging, CMOS fast imaging, broad, medium, and narrow band imaging, low surface brightness capability, fast filter change (~10s) and fast (~10s) readout, rapid-response capability, and real-time data processing and source identification for minutes later spectroscopic capability. I will discuss a UV-sensitive optical wide-field imager for the GTC, unique and leading-edge science it will do, and why it will keep GTC a leader in the ELT era.

 The fate of massive stars and the type of supernova (SN) they produce are closely linked to their final stages of evolution. During these late phases, stars may undergo episodic mass loss, forming circumstellar material (CSM) that can leave observable signatures in the SN spectra, particularly as resonance lines in the near-ultraviolet (NUV). In this talk, I will present a sample of superluminous supernovae (SLSNe), an exceptionally luminous class of SNe, focusing on the NUV spectroscopy to search for signatures of recently ejected CSM shells. I will first discuss two SLSNe in which CSM shells are detected, inferring their properties and the timing of the ejection, along with implications for the underlying mass-loss mechanisms and progenitor systems. I will then extend the analysis to the full sample, modelling the spectral regions where CSM-related features are expected in order to evaluate how common such mass-loss episodes are and to place constraints on undetected CSM shells. These results provide new insights into the final stages of massive star evolution and help constrain the nature of SLSN progenitors.