Proyectos en marcha aprobados y financiados por fondos externos

(English) In the hierarchical formation model, galaxies assemble their mass over their lifetimes through accretion and mergers with smaller galaxies. As they grow in mass, they also grow in size as dwarf galaxies until they reach ~M∗<10e9M⊙, at which point they continue to grow in mass without changing in size until they transform into the massive ellipticals and spirals. This transition and increasing complexity of the morphology of the galaxy coincides with the peak in the fraction of galaxies containing nuclear star clusters (NSCs), as well as the dominant mechanism for building NSCs- in dwarf galaxies they accrete mass from migrating star clusters in while in the massive galaxies the dominant process is in-situ star formation fuelled by infalling gas. However, the role of NSCs in galaxy mass assembly, and how galaxies develop their bulge and disc structures over time, remain open questions.

The focus of this project is to understand how galaxies transform their morphologies as they accrete mass by studying how the bulges and discs form end evolve, and the role of the NSCs in this process. I will disentangle the spectra and study the stellar populations within each component, such as the bulges, discs and NSCs. Through this stellar populations analysis, I will be able to answer many open questions regarding the internal processes through which galaxies build their mass and how their morphologies transform over time.

FUNDING SOURCE: FONDECYT Iniciación de investigación

PERIOD: 2021-2024

(English) Based on PI programs with ALMA. The proposed research ranges from the characterization of disk outflows from molecular line data at low spatial resolution (100 au scales) to the ultra-high-resolution (3-5 au) continuum observations of very bright and massive protoplanetary disks. The project also includes dust evolution modeling to investigate the formation and evolution of substructures in protoplanetary disks and multi-frequency studies combining ALMA and VLA data.  In parallel to the ALMA studies of protoplanetary disks, we will continue with the dust opacity measurements at the UDP Cosmic Dust Laboratory. The laboratory started operations measuring the IR dust opacities of different families of meteorites as a function of grain size distribution. As remnants of the Solar Nebula, meteorites are the best analogs of the type of dust expected in protoplanetary disks. We will now extend our opacity measurements to the submillimeter regime and design the experiments to be directly relevant to ALMA observations of disks by 1) preparing samples with realistic grain size distributions, 2) performing measurements at the low temperatures present in disks, and 3) mixing dust with ices with different mass fractions to mimic the different types of dust that are expected across the protoplanetary disk.

FUNDING SOURCE: FONDECYT Regular de Investigación

PERIOD: 2021-2024

(English)

FUNDING SOURCE: FONDECYT Regular de Investigación

PERIOD: 2021-2024

(English) Actively accreting super-massive black holes, also known as Active Galactic Nuclei or AGN, are some of the most luminous objects in the Universe at all wavelengths. The large amount of energy they inject into the surrounding galaxy is thought to play a fundamental role in regulating its stellar mass growth, making them key drivers of galaxy evolution. The majority of the luminosity output in luminous AGN comes from the accretion disk surrounding the SMBH up to the last inner stable orbit. If unobscured, the emission of this disk would typically dominate the SED from the UV to the near-IR. However, there can be copious amounts of dust at larger scales (most notably from the dust torus, but also from the host galaxy ISM) that can easily obscure the UV and optical emission. The dust from the torus absorbs the accretion disk radiation and then reradiates it in the mid-IR, making that wavelength range an ideal one on which to identify obscured and unobscured luminous AGN. In this FONDECYT project I will focus on studying different classes of mid-IR selected AGN, with the aim of better understanding their role in galaxy evolution, their structure and their environments, as well as their statistical properties relying in very large samples. Specifically, I will focus on i) Hot Dust Obscured Galaxies, a population of hyper-luminous obscured AGN discovered by the WISE mission, and ii) on sources from the WISE-selected AGN catalogs of Assef et al. (2018a) with emphasis on luminous transients.

FUNDING SOURCE: FONDECYT Regular de Investigación

Period: 2019-2023

(English)

FUNDING SOURCE: FONDECYT Regular de Investigación

Period: 2019-2023

(English) Gravitational waves can be rigorously defined at the radiative ‘end’ of a space time. This limit is usually called null infinity (i.e. the infinity at the ‘end’ of null rays ).
For asymptotically flat spacetimes, the definition of  angular momentum and its fluxes at null infinity suffer the so-called supertranslation ambiguity.   Roughly speaking this  ambiguity results from the fact that cuts at null infinity can be described by different (arbitrary) scalar functions  – the supertranslations –   depending on spherical angles. Mathematically speaking supertranslations are elements of the Bondi-Metzner-Sachs (BMS) group at null infinity which contains representations of the Poincaré group of Special Relativity as subgroups. However a Poincare group (e.g. one for which angular momentum is zero) cannot be picked out uniquely from the BMS group due to the presence of the supertranslations. This makes it difficult to determine  angular momentum and its flux at null infinity. Gravitational wave memory  – which is the irreversible displacement of test particles due the the passage of a gravitational wave – can be related to supertranslations. The idea of the project is to give an operational definition of angular momentum and its flux using the gravitational wave memory
of radiative  compact object space times.

FUNDING SOURCE: FONDECYT Iniciación de Investigación

Period: 2020-2023

(English) With the aim of generating a more inclusive astronomical community, which takes into account the different needs and auditory, visual and physical capacities of people, the Inclusion and Gender Working Group of the Chilean Astronomy Society (SOCHIAS), with Erika Labbé as PI, it proposes to incorporate into its work a team of advisers who come from the communities of people with disabilities, for the co-creation of recommendations for events, dissemination and research, in the construction of surveys, and that they carry out training online on inclusion and accessibility, along with a basic course in Chilean Sign Language (LSCh), with the aim of forming ourselves as a community on these issues.

In addition, we will hire external experts to conduct training on inclusion and gender issues. The trainings will be directed to SOCHIAS members who are interested, extending the invitation to participate to those in charge of communication from the different Nuclei, Millenniums, Institutions, Universities and Colleges / centers that disseminate Astronomy.

FUNDING SOURCE: ALMA-ANID

PERIOD: 2021-2022

(English) This grant is to hire a postdoc (Claudia Aguilera-Gómez) to study rocky exoplanets compositions using an interdisciplinary approach. Our aim is to investigate whether planetary bodies retain the same composition as the material from which they formed, i.e., their host star. To do this, we will utilise white dwarfs that have accreted planetary material from an outer planetary system that survived the star’s evolution, a.k.a. polluted white dwarfs.
In order to determine the composition of the white dwarf’s progenitor, we will perform chemical analyses of wide binaries composed of a polluted white dwarf and a distant main sequence companion. By comparing the composition of the exoplanetary material accreted by the white dwarf to the composition of the binary, we will better understand how planet formation controls composition. Crucially, if the refractory composition matches, this means that host-stars can be used to constrain the composition of observed exoplanets.

FUNDING SOURCE: ESO-Chile Joint Committee

PERIOD: 2021-2022

(English) In this project, we are working to discover and characterise some of the most extreme planetary systems currently known to exist. We will leverage the rich array of observational facilities that we have access to here in Chile, in order to exploit the large catalogues of transit planet candidates offered by the Transiting Exoplanet Survey Satellite (TESS) and Next Generation Transit Survey (NGTS) missions. We are mainly focused on gaining a better understanding of the so-called ‘Neptune Desert’ region of the orbital period and planetary radius parameter space. The Neptune Desert is a region relatively devoid of planets with orbital periods below around 5 days, and with sizes similar to that of Neptune in our own Solar System. Theoretical models that invoke photoevaporation of the planetary atmosphere from the high stellar irradiation environment can mostly explain the paucity of planets, but we aim to investigate to what level additional effects such as Roche Lobe Overflow of the planetary atmosphere comes into play. One key way we are aiming to move forward in this area is by detecting more benchmark planets inside the Neptune Desert, those like LTT9779b (Jenkins et al. 2020), and then following them up from the ground with high precision echelle spectrographs (e.g. ESPRESSO & CRIRES+) and space-based precision photometers (e.g. CHEOPS & TESS) in order to better understand the chemistry and physics of their atmospheres. By incorporating a multi-level approach, we aim to gain a deeper understanding of planet formation and evolution in general.