lunes 27 de noviembre
SALÓN DORADO (120)
10:35 - 11:15
COFFEE BREAK
11:15 - 12:45
H: ISM and Local Universe
ISM
Chair: Mónica Rubio
#050 |
Through the Dust Veil: a Submillimeter and Infrared View of the Closest Starbursts with Interferometers and JWST
Alberto Bolatto
1
1 - University of Maryland at College Park.
Resumen:
Starbursts occur in galaxies that during certain periods in their lives form stars at rates 3-100 times higher than their average during cosmic history. In the z=0 universe they take place mostly when gas is injected into the central regions of galaxies by toques associated with bars or gravitational interactions. Starbursts cannot be observed well in the optical thanks to the high columns of dust that obscure these regions, but observations at infrared and submillimeter wavelengths show that significant fractions of the new stars are formed in massive compact clusters. The mechanisms regulating the formation and dissipation of these clusters are not well understood. The cumulative effects of radiation, stellar winds, and supernovae created by their massive stars set up high pressures in the interstellar medium of these starburst regions that result in galactic scale winds and the ejection of enriched material to the circumgalactic medium. In this presentation I will show interferometric (ALMA, NOEMA, SMA) and JWST results in the central starburst regions of two of the closest starburst galaxies: M82 and NGC253.
#048 |
The extremely sharp transition between molecular and ionized gas in the Horsehead nebula revealed by ALMA
Claudio Hernández-Vera
1
;
Viviana Guzmán
1
;
Javier Goicoechea
2
;
Vincent Maillard
3
;
Jérôme Pety
4
;
Franck Le Petit
3
;
Maryvonne Gerin
3
;
Emeric Bron
3
;
Evelyne Roueff
3
;
Alain Abergel
5
;
Thiébaut-Antoine Schirmer
6
;
John Carpenter
7
;
Pierre Gratier
8
;
Karl Gordon
9
;
Karl Misselt
10
1 - Pontificia Universidad Católica de Chile.
2 - Instituto de Física Fundamental (CSIC).
3 - LERMA, Observatoire de Paris.
4 - Institut de radioastronomie millimétrique (IRAM).
5 - Université Paris-Saclay.
6 - Onsala Space Observatory.
7 - Joint ALMA Observatory.
8 - Laboratoire d’Astrophysique de Bordeaux.
9 - Space Telescope Science Institute.
10 - University of Arizona.
Resumen:
Massive stars can determine the evolution of molecular clouds by eroding and photo-evaporating their surfaces with strong UV radiation fields. Thus, probing the fundamental structure of nearby molecular clouds is crucial to understand how massive stars shape their surrounding mediums and how fast molecular clouds are destroyed. By combining CO $J=3-2$ and HCO$^{+}$ $J=4-3$ data from the ALMA 12m array, the Atacama Compact Array (ACA) and Total Power (single-dish), we present the highest angular resolution ($\sim 0.5^{\prime\prime}$, corresponding to $207$~au) and velocity-resolved images of the molecular gas emission in the Horsehead nebula. We find that CO and HCO$^{+}$ are present at the edge of the cloud, very close to the ionization (H$^{+}$/H) and dissociation fronts (H/H$_{2}$), suggesting a very thin layer of neutral atomic gas and almost no CO-dark H$_{2}$ gas at the molecular cloud edge. Notably, the HCO$^{+}$ emission map exhibits a bimodal behavior, tracing the cold and dense gas shielded from UV radiation and a more diffuse gas component interacting directly with the UV radiation field. Additionally, using CO as a proxy of the C$^{+}$/C/CO front, we conclude that the distances between the fronts can be reproduced by isobaric stationary models, which confirms the presence of a steep density gradient, as suggested by previous observations. Still, dynamical effects cannot be completely ruled-out, and even higher angular observations will be needed to unveil their role.
#467 |
An Integrated H$\alpha$ Flux Atlas of Planetary Nebulae in the Magellanic Clouds: Combining S-PLUS Photometry and Spectroscopic Analysis
Luis Angel Gutiérrez Soto
1
;
Amanda Lopes
1
;
Analia Smith Castelli
1
1 - Instituto de Astrofísica de La Plata.
Resumen:
We present an atlas of integrated H$\alpha$ fluxes for planetary nebulae (PNe) in the Magellanic Clouds (MC) using data from the Southern Photometric Local Universe Survey (S-PLUS), a comprehensive 12-band imaging survey. One of the key aspects of our study lies in the detailed spectroscopic analysis of the weak nebular emission in the PNe. Through spectroscopic data, we were able to quantify various emission lines, including H$\alpha$ and [N II], which play a pivotal role in understanding the ionization state and elemental abundances within these nebulae. The spectroscopic data not only enhances the accuracy of our flux measurements but also provides crucial insights into the physical and chemical properties of the MC PNe. By studying the distribution of ionized gas within the nebulae and examining density variations, we gained valuable information about their structures and evolutionary processes. Furthermore, the comparison of our findings with previous spectroscopic measurements from the literature validates the robustness of our results and reinforces the significance of spectroscopy in unraveling the mysteries of these intriguing celestial objects. In conclusion, our combination of imaging data from S-PLUS with extensive spectroscopic analysis has enriched our knowledge of MC PNe, shedding light on their intricate properties and providing new dimensions to our understanding of their diverse population.
#384 |
Hidden jets in planetary nebulae and how to find them
Jackeline Suzett Rechy-García
1
;
Martin A. Guerrero
2
;
Jesús A. Toalá
3
;
Sara Cazzoli
2
;
Gerardo Ramos-Larios
4
;
Laurence Sabin
5
;
Edgar Santamaría
3
;
Denise R. Gonçalves
1
;
Stavros Akras
6
1 - Valongo Observatory, Federal University of Rio de Janeiro.
2 - Instituto de Astrofísica de Andalucía.
3 - IRyA-UNAM.
4 - Universidad de Guadalajara.
5 - Instituto de Astronomía-UNAM.
6 - Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens.
Resumen:
Almost 80\% of the planetary nebulae (PNe) are non-spherical - elliptical, bipolar, point-symmetric, among others - sometimes showing knots, filaments and jets of low ionization (the low-ionization structures, LIS), and others features of small scales. The presence of stellar jets in PNe has been investigated through morpho-kinematic studies, from narrow-band images and position-velocity maps constructed from high-dispersion, long-slit spectroscopic observations. However, this spectroscopic technique limits the understanding of the global three-dimensional structure of the PNe, since the spatial and spectral information are only obtained along a given orientation. Integral field units (IFU) allow the spatial and kinematics mapping of PNe, for both their small- and large-scale components, to determine their morphology, kinematics, density distribution and the interaction zone of the jets with the surroundings. Many of the stellar jets have only been unveiled through this modern instrumental technique. In this talk I will present results obtained with the optical IFU MEGARA, which highlight the hidden ways that PNe ejecta return their products to the interstellar medium, in a variety of morphologies. In particular: i) the extension of the extremely faint bipolar jet in NGC 2392, mapped for the first time; ii) the kinematic dissection of the born-again HuBi 1; iii) the multiple structures of the M 2–31; iv) the presence of a fast outflow aligned with the symmetry axis of M3-38; and finally, v) the advances obtained for the myriad of shells and LIS in NGC 6543.
#316 |
Radio spectra of the classical nova V5668 Sgr
Zulema Abraham
1
1 - Departamneto de Astronomia/IAG/USP.
Resumen:
V5668 Sgr is a classical nova that erupted on 2015 March 15. Since then, it was detected along the whole elctromagnetic spectrum, from radio to $\gamma$ rays. On day 927 after eruption, it was observed with ALMA in the 230 GHz continuum with high spatial resolution, showing for the first time that an evolved classical nova shell is formed by a large number of small clumps of dense ionized plasma.
In this work we analyse the evolution of the radio spectra (1-35 GHz) of V5668 Sgr obtained with the VLA, and show that they are compatible with the assumption that the clumps were formed in the early epochs of the nova evolution, when fast winds from the surface of the white dwarf overtook the slower shell ejected during the eruption, producing radiative shocks. The time evolution of the density in the clumps is compatible with the existence of tenuous and hot material in pressure equilibrium with the clumps, which at early epochs was responsible for the observed (1-10) keV X-rays.
#155 |
Unveiling the 3D geometry of nova shells with MUSE
Lientur Celedón
1
;
Linda Schmidtobreick
2
;
Claus Tappert
1
;
Fernando Selman
2
1 - Instituto de Física y Astronomía - Universidad de Valparaíso.
2 - European Southern Observatory.
Resumen:
Nova eruptions occur in Cataclysmic Variables when enough material has been accreted onto the surface of the White Dwarf primary. As a consequence, the material that has been accumulated until then is expelled into the Interstellar Medium (ISM), forming an expanding nova shell around the system. Understanding the physical process that shapes the morphology of nova shells is essential to fully comprehending how the ejection mechanism operates during nova eruptions.
The use of Integral Field Spectroscopy (IFS) is a technique that has received little attention in the study of nova shells, despite its advantages in studying their morphology and kinematics. In this talk, I will present our preliminary results regarding an IFS study of several nova shells, with particular emphasis on the study of their morphology.
These shells were observed using the Multi-Unit Spectroscopic Explorer (MUSE) instrument located at the ESO-VLT observatory. All these shells have been previously observed almost 2 decades ago, which allows us not only to study how they look today but also how have they evolved during this time.
The MUSE observations were able to detect a nova shell in the H$\rm\alpha$ line in most of our selected systems, and in some cases also in H$\rm\beta$, [O{\sc iii}] and/or [N{\sc ii}]. Comparison with previous images supports a free expansion of these nova shells, which allows us to convert the observed space within the datacube into a proper physical space.
Each nova shell within our sample shows a characteristic and unique geometry, though some present similarities between them.
Many of them show morphologies that challenge the common perception of nova shells with simple prolate geometries. Taking account of these new results will help us to have a better understanding of the ejection mechanism and/or the interaction with the ISM that shapes the geometry of nova shells.
12:45 - 14:30
LUNCH
15:50 - 16:30
COFFEE BREAK
16:30 - 17:15
E: Sun and Heliosphere
Sun and Helioshere
Chair: Mario Melita
#152 |
Bayesian inference of global magnetic parameters of solar active regions
Mariano Poisson
1
;
Marcelo López Fuentes
1
;
Cristina Hemilse Mandrini
1
;
Francisco Grings
1
;
Pascal Démoulin
2
1 - Instituto de Astronomía y Física del Espacio (CONICET-UBA).
2 - LESIA, Observatoire de Paris, Université PSL, CNRS.
Resumen:
Active regions (ARs) appear in the solar atmosphere as the consequence of the emergence of magnetic flux tubes formed in the solar interior. Several observational evidence, models and simulations have shown that these coherent structures must carry magnetic helicity, forming magnetic flux ropes (FRs). Since these FRs are the most important means by which magnetic energy is transported out to the solar atmosphere, its study is fundamental to fully comprehend energy release processes such as flares and coronal mass ejections. However, acquiring precise estimations of their intrinsic magnetic parameters during the early phase of the ARs evolution is limited to the observed photospheric magnetic flux distribution. In particular, the observed line-of-sight (LOS) component of the photospheric magnetic field can be affected by the amount of twist on these FRs producing a departure of the expected symmetric bipolar configuration. In this work, we aim to model the magnetic parameters of emerging FRs using a Bayesian scheme. We model the 3D structure of the FR with a magnetic field with a geometry defined by a half-torus with uniform torsion. This 8-parameter model can produce a sequence of synthetic LOS magnetograms by projecting the vertical component over transversal planes at different heights relative to the center of the torus. We perform the inference over a sequence of LOS magnetograms of four different emerging ARs. We test and compare submodels in which different temporal correlation of the parameters are considered. We found that the inferred magnetic parameters such as the magnetic helicity and tilt angle obtained for all the studied ARs are consistent with other previous estimations.
#522 |
Application of \textit{Deep Learning} techniques in modeling and observation of the solar photosphere.
Nicolas Morales
1
;
Juan Agudelo
1
;
Santiago Vargas
1
;
Sergiy Shelyag
2
1 - Universidad Nacional de Colombia.
2 - Flinders University.
Resumen:
The present work is framed within the applications of deep neural networks for modeling phenomena present in the solar photosphere. The proposed research is based on the construction of a deep 3D generative convolutional neural network, known as DCGAN (Deep Convolutional Generative Adversarial Network), utilizing Python's artificial intelligence modules such as Pytorch for the neural network architecture. The goal is to train a neural network capable of generating groups of cubes highly similar to training cubes. These cubes correspond to physical quantities of the solar photosphere, such as density, magnetic field, plasma velocity, temperature, among others, obtained from the MURaM simulation code. The aim is to generate realistic simulations of magnetoconvection processes and magnetic activities that occur in the solar convective zone. This work employs the simulation results as training data for the neural network, generating new data with consistency in the physical parameters. Subsequently, a comparison is made between the original simulated results and the training data, and challenges are proposed and discussed for using these tools in the study of the solar photosphere, flux tubes, and pores.
17:15 - 18:00
F: Planetary Systems & Astrobiology
Minor bodies
Chair: Mario Melita
#131 |
Physical properties of Centaurs based on JWST/NIRSPEC spectroscopy: the early formation of dust mantles.
Javier Licandro
1
;
Noemi Pinilla Alonso
2
;
John Stansberry
3
;
Mario de Pra
2
;
Mario Melita
4
;
Ana Carolina de Souza Feliciano
2
;
Bryan Holler
3
;
Vania Lorenzi
5
;
Rosario Brunetto
6
;
Ian Wong
7
;
Dean Hines
3
;
Johnatan Lunine
8
1 - Instituto de Astrofisica de Canarias.
2 - University of Central Florida.
3 - Space Telescope Science Institute.
4 - Instituto de Astronomia y Fisica del Espacio (IAFE), UBA-CONICET.
5 - Centro Galileo Galilei, INAF.
6 - IAS, Université Paris-Saclay, CNRS.
7 - NASA Goddard Space Flight Center.
8 - Department of Astronomy, Cornell University.
Resumen:
Centaurs are a dynamical class of small icy bodies of the solar system, short-time residents (less than 10\^7 yr) in the region between Jupiter’s and Neptune’s orbits. They are scattered from the trans-Neptunian belt (TNB) and a fraction of them become Jupiter family comets (JFCs) during even shorter lifetimes (10\^5 yr). Centaurs are an intermediate population, halfway between the distant, cold, and relatively stable bodies in the and the rapidly sublimating comets of the hot inner regions. Remarkably, some Centaurs (about 10 \%) show comet-like activity even when they are beyond the orbit of Jupiter, which suggests mass loss driven by a process, which is different from the sublimation of water ice. In their chaotic orbital evolution, some of them spend part of their life as Jupiter family comets.
The study of their surface properties is important to understand the link between trans-neptunian objects (TNOs), Centaurs and comets, and how their surface composition evolve whit the time they spend at distances from the Sun were volatiles like CO and CO2 can sublimate.
Near-infrared spectral observations of 10 Centaurs were obtained with the James Webb Space Telescope (JWST) Near-Infrared Spectrograph (NIRSpec) as part of the Guaranteed Time Observers (GTO) program and the 2418 DiSCo-TNOs (Discovering the composition of the trans-Neptunian objects) program (PI: Pinilla-Alonso). JWST’s exquisite sensitivity in the 1-5 micron region allow to obtain high SNR Low-resolution spectra in the 0.6-5 microns region, which provide unique surface compositional information. Ices (H2O, CO2, etc), complex organic and silicates can be identified. We show that two compositional groups as in the TNO population,on dominated by water and silicates and other dominated by carbon species coexist in the Centaur population but with less volatiles than TNOs and a larger fraction of silicate particles (dust) deposited on their surfaces during their active phases.
#331 |
Physical Properties, Source Regions, and Total Mass Flux of Decimetre-Sized Aggregates around 67P/Churyumov-Gerasimenko
Pablo Lemos
1
;
Jessica Agarwal
1
;
Raphael Marschall
2
1 - TU Braunschweig.
2 - Côte d’Azur Observatory.
Resumen:
During its orbit around comet 67P/Churyumov-Gerasimenko (67P), the Rosetta mission obtained a plethora of invaluable data. In particular, dust particles with sizes up to ~0.1 mm were individually sampled and analyzed by dust collectors, while larger particles were remotely observed by the OSIRIS imaging system. Unfortunately, the remote sensing method provided only the particles' position and velocity projected onto the image plane, lacking data regarding the distance to the camera and line-of-sight velocity.
To address this issue we propose a novel approach based on statistically comparing bright tracks observed in OSIRIS images with synthetic images. We implemented a semi-automatic method to detect bright tracks in multiple sets of OSIRIS images. Next, we generated synthetic images by modelling the trajectories of dust aggregates in the cometary coma, influenced by gas drag, gravity from the 3D shape model of the nucleus, solar radiation pressure, and solar tides. Lastly, the trajectories were combined with the camera's position and pointing, in order to generate synthetic images of the aggregates as OSIRIS would have observed them. This novel methodology allowed us to extract essential physical parameters of the aggregates, including size and density, while also uncovering information about their ejection, such as the source region and initial velocity, which are related to the mechanisms causing the ejections themselves. Using the particle parameterns, this approach also allows to estimate the mass flux of large particles into the tail and trail of the comet.
#031 |
Gaia$^\prime$s view of hydrated asteroids
Anthony Brown
1
;
Joost Barendse
1
;
Marco Delbo
2
;
Ashish Mahabal
3
1 - Leiden Observatory.
2 - Observatoire de la Cote d$^\prime$Azur.
3 - California Institute of Technology.
Resumen:
Gaia DR3 presents the reflectance spectra of some 60000 asteroids in the solar system. We analysed these spectra in an attempt to detect the feature in the spectra around 650 nm, the OH band, which is indicative of primitive aqueous alteration, namely that in the parent body (or parent planetesimal) of the asteroid where the OH feature is seen, liquid water was present at some point. In combination with the data on asteroid orbits provided by Gaia, an analysis of this feature can provide insights into where hydration (i.e. water) was present in the primitive solar system.
We present the results of applying a machine learning method to classify asteroid spectra as showing or not showing the hydration feature. The resulting set of asteroids where the OH band may be present are analyzed in terms of their orbital properties. The search for such asteroids is subsequently extended to the Zwicky Transient Faciliity photometric database with the aim to uncover more candidate astreroids with OH bands.
