List of all the talks in the archive, sorted by date.
In this talk, I will present the highlights from our recent study of 22
local (z < 0.025) type-1 LINERs from the Palomar Survey, on the basis of
optical long-slit spectroscopic observations taken with TWIN/CAHA,
ALFOSC/NOT and HST/STIS (Cazzoli et al. 2018, MNRAS 480, 1106–1162).
In this study, we explored the AGN-nature of these type-1 LINERs by
studying the broad (BLR-originated) Hα component. Then, we derived
reliable interpretation for the different component of emission lines by
studying their kinematics and ionization mechanism. Finally, we studied
the neutral gas in the nuclei of these LINERs by modeling of the NaD
The Sloan Digital Sky Survey (SDSS) is one of the most successful and prolific projects in the history of Astronomy.
In its fifth iteration SDSS-V (2020-2025) will provide a more comprehensive, global picture of the local universe by
studying the interplay between galactic genesis, stellar and black hole processes, and the physics of the ISM. I will
review the main science goals of the project, the exciting new hardware being implemented (robot fibre positioner,
large IFU systems), and the operational challenges. As in its previous incarnations, SDSS-V remains committed to
providing high-quality data products for the astronomical and educational communities. I will discuss some of the
new ideas being developed for SDSS-V with regards to data reduction, release, archival, and visualisation.
The advanced stages of high-mass stars are characterized by episodic mass loss shed during phases of instability. Key for assigning these stars a proper evolutionary state is to assess the composition and geometry of their ejecta alongside the stellar properties. I will speak about my work to increase the number of B[e] supergiants, Yellow Hypergiants and Luminous Blue variables in the Local Group by investigating circumstellar environments and exploring the evolutionary properties of high-luminous, dusty targets. By conducting and analyzing optical spectroscopy alongside fitting the spectral energy distribution, I derive stellar properties and infer the presence of circumstellar dust. In search of processed ejected material, modeling of the CO band heads in the K-band is further employed. Results of my work in M33 include the discovery of a strong Yellow Hypergiant candidate showing evidence of past eruption. Moreover, the insight into the surrounding molecular environment witnesses the presence of circumstellar/binary disks around post-supergiant/evolved stars. I highlight the importance of the infrared data to resolve the evolutionary status of massive stars and thus, to constrain the physics of the diverse pre-supernova stellar states. Finally, I will speak about my work at IAC regarding the photometric properties of OB stars in conjunction to the latest Gaia Data Release 2 and their possible link to the line-broadening status of the stars.
Starlight principles and recommendations are brought together in the “Declaration in Defence of the Night Sky and the Right to Starlight” (“La Palma Declaration.” 2007), in which, in addition to the IAC, representatives of UNESCO, UNWTO, IAU, UNEP-CMS, CE, SCBD, COE, MAB and the Ramsar Convention all participated and launched Starlight as an international movement in defence of the sky by night and day and to treat it as a source of knowledge and culture that should be shared with society as a whole, promoting the dissemination of astronomy and sustainable, high-quality tourism in those places where the night sky is cared. The Starlight Reserves, Tourist Destinations and other modalities are scenarios that incorporate the observation of the sky as part of the natural, scenic, cultural and scientific heritage and encourage “Star Tourism”, promoting infrastructure, products, activities and training of specialized guides in the field of sustainable tourism. The Starlight Foundation has been selected to lead the UNWTO Affiliate Member Working Group on Scientific Tourism. Updated Starlight certifications and current projects will be summarized in this presentation.
The SDSS Apache Point Observatory Galactic Evolution
Experiment (APOGEE) has
collected high resolution near-IR spectra of several hundred thousand stars
across the Milky Way. I'll describe some observational results about the
spatial variation of chemical abundances as a function of Galactocentric
radius and distance from the midplane, discussing mean abundances,
distribution function, and the variation of abundance ratios of multiple
elements. Additional information related to stellar ages can be obtained
from [C/N] for red giant stars. Several lines of evidence suggest that
migration has had a significant impact on the Galactic disk. The
observed patterns of
abundance ratios may provide observational constraints on
The growth of astrophysical understanding typically results fromthe constructive interplay between theoretical ideas andobservational insights, with each mode of exploration drivingprogress at different times. The result is invariably a morecomplicated but richer picture of the phenomenon than initiallyenvisaged, as well as deeper appreciation of the behavior ofcomplex systems.In this talk, I will use the development of our understanding ofthe structure of outflows from massive O- and B-type stars toillustrate this collaborative “dance”. Starting from the smooth,spherically symmetric models for radiatively driven windsdeveloped in the late 1960s, our view of these outflows hasevolved to include the growth of inhomogeneities on a variety ofspatial scales. Explanations for the origin of this structure havein turn prompted the realization that non-radiative processesmust also shape the emergence of the wind from the stellarphotosphere. Consequently, O- and B-type stars are morecomplicated – and interesting! – objects than often thought.While many fruitful avenues of research remain to be explored,the current paradigm provides a (mostly) self-consistent pictureof massive stars and their outflows.
The bimodal distribution of red and blue galaxies can often be linked through a quenching mechanism that can attenuate the active star forming galaxies into passive ones. Both environment and the stellar mass play an important role in this transition. The ram pressure stripping (RPS) is an important environmental mechanism in dense environments that can severely change the properties and morphology of galaxies. The most extreme cases of galaxies undergoing RPS are known as jellyfish galaxies. Studying this transitioning piece is crucial to improve our understanding of the evolutionary path of galaxies and how quenching succeeds in galaxy clusters. However, jellyfish galaxies are not well characterised morphologically and finding them is still a complex task based mainly on visual inspection. We present the results of a comprehensive study on the properties of a large sample of jellyfish candidates in the multi-cluster system A901/2. We find evidence that the multi-cluster is triggering the effects of RPS in preferential regions in the system and that these galaxies show an enhancement in their star formation rates. We also use the software Morfometryka in order to analyse the unique morphometric features in jellyfish galaxies providing a better comprehension of their physical state and future. This can help unravel the physical processes behind such extreme morphologies as well as helping to automatise the search for jellyfish galaxy candidates in large surveys.
- Gamma-ray AstrophysicsDr. Mónica Vázquez AcostaTuesday July 23, 2019 - 12:30 (Aula)
- COLLOQUIA: Supernova DustProf. Mike BarlowThursday July 25, 2019 - 10:30 (Aula)