viernes 01 de diciembre
SALÓN ROJO (150)
10:20 - 11:00
COFFEE BREAK
11:00 - 11:45
B: Facilities, Technologies and Data Science
Techniques and Instruments
Chair: Eleonora Sani
#414 |
Airglow vs. Skyglow: a portable optical spectrograph for the analysis of natural and artificial light at night
Juan Pablo Uchima-Tamayo
1
;
Rodolfo Angeloni
2
;
Marcelo Jaque
1
1 - Universidad de La Serena.
2 - Gemini Observatory, NSFs NOIRLab.
Resumen:
The detrimental effects of light pollution on astronomy, ecology, and human health are intimately linked to the development, and subsequent misuse, of the rapidly evolving lighting technology. Because of the so-called LED revolution, in the course of the last decade, the Spectral Power Distribution (SPD) of man-made light pollution has been shifting from one containing a few emission lines to one containing dozens - if not hundreds - of lines, along with a significantly increased continuum level in the blue-green spectral range. Because of this SPD reshaping, there is ever growing evidence that most of the photometric technologies and techniques that have so far been used to monitor light pollution worldwide are not able to cope with the massive and fast spread of LED sources. Therefore, the only way to make a significant leap forward in the quantitative characterization of this phenomenon is through spectroscopy, a technique capable not only of disentangling the different contributions to the Night Sky Brightness (NSB), but also of following its complex, multiperiodic variability.
In this talk, I will introduce our interdisciplinary project aimed at developing a portable optical spectrograph for the first-ever spectral monitoring of the Chilean night sky. This device will be capable of capturing low-resolution flux-calibrated spectra of large sections of the celestial sphere at once. With its lightweight, modular, and versatile design, it will enable a comprehensive spectral characterization of both natural and artificial sources of NSB. We will eventually gain an accurate understanding of how light pollution affects the upper half of the Chilean horizon, a natural and cultural heritage that is our scientific, social, and moral obligation to protect and preserve.
#298 |
BOCOSUR: an all sky network for fireball detection in Uruguay
Manuel Caldas
1
;
Alvaro Guaimare
1
;
Valeria Abraham
1
;
Lucas Barrios
1
;
Matías Hernández
1
;
Lucía Velasco
1
;
Gonzalo Tancredi
1
1 - Dpto. Astronomía, Facultad de Ciencias.
Resumen:
During the last decade several networks for automatic detection of fireballs have been deployed, with the main scientific goal of enabling a rapid recovery of meteorites and determination of its parent's pre-atmospheric orbit. The geographical distribution of these networks is heavily biased towards the Northern hemisphere. The Bocosur network is a contribution to the global deployment of automated fireball networks, and particularly to the unbiasing of their geographical distribution, since it is located in Uruguay, South America (Lat: -30° to -35°). Its main scientific goal is the detection of fireballs of asteroidal origin, massive enough to produce meteorites, and also to inspire secondary-level students and teachers through their involvement in this citizen-science oriented project. The deployment of this network started in 2019, and was completed in March, 2023, when we installed 20 stations separated ~120 km, covering an area of ~ 180,000km2. During this period of time, one major technological upgrade was made when we migrated from a well-known camera to a higher-resolution, more sensitive system. We were able to build a completely autonomous system at an affordable cost that can be replicated in all the stations. A comparison between the astrometric and photometric performance of these two detection systems is reported. Also, a photometric methodology for estimating the brightness of very bright fireballs is presented and validated against the known magnitudes of Jupiter and the full Moon. We obtain mean residuals of the astrometric reduction of ~5', and the discrepancy between the obtained brightness of Jupiter and the Moon average to 0.18 and 1.0 magnitudes, respectively.
#353 |
Semi-Supervised Domain Adaptation for Multi-band Photometric Supernovae Classification
Jorge Saavedra-Bastidas
1
;
Daniel Moreno-Cartagena
2
;
Manuel Pérez-Carrasco
3
;
Guillermo Cabrera-Vives
2
1 - Astronomy department, Universidad de Concepción.
2 - Department of Computer Science, Universidad de Concepción.
3 - Data Science Unit, Universidad de Concepción.
Resumen:
The transient objects known as supernovae constitute one of the most exciting laboratories of study in various areas of astronomy because of their involvement in different physical processes. The large influx of current data leads us to search for new ways to correctly classify these objects in the shortest amount of time possible, even when reliable labels are scarce. In this paper, we present a novel approach that extends the Minimax Entropy semi-supervised learning algorithm to the classification of multiband time series data and tests it on observational light curves of different supernova categories obtained by forced photometry from the Zwicky Transient Facility (ZTF). We quantify the performance of our classifier according to the number of real supernova light curves delivered during the learning period as well as the evolution of its performance based on the number of observations per supernova available when predicting with new data. Our results show that the classification accuracy improves over the lifetime of the transient as more photometric data become available. We demonstrate the ability of our model to provide early classifications of observed transients from the ZTF data stream compared to fully supervised classification models.
11:45 - 12:30
D: High Energy Phenomena and Fundamental Physics
Gamma-Ray Sources and Cosmic Rays
Chair: Eleonora Sani
#547 |
Machine Learning Explorations in GRB Studies: From Classification to Extended Emission Identification
Keneth Garcia-Cifuentes
1
;
Rosa Leticia Becerra Godinez
2
;
Fabio De Colle
2
1 - Universidad Nacional Autónoma de México.
2 - Universidad Nacional Autónoma de México, Instituto de Ciencias Nucleares.
Resumen:
Gamma-ray bursts (GRBs) have traditionally been categorized based on their durations. However, the emergence of extended emission (EE) GRBs, characterized by durations higher than 2 seconds and properties similar to short GRBs, challenges conventional classification methods. In this talk, we delve into GRB classification, focusing on a non-supervised machine-learning technique (t-distributed stochastic neighbor embedding, t-SNE) for classification and the identification of extended emission in GRBs.
Furthermore, we introduce an innovative tool, ClassipyGRB, designed for astronomers whose research centers on GRBs. This versatile Python3 module enhances the exploration of GRBs by offering interactive visualizations of their light curves and highlighting shared attributes. With ClassipyGRB, astronomers can swiftly compare events, identifying resemblances and exploring their high-frequency characteristics. This tool uses the power of proximity analysis, enabling rapid identification of similar GRBs within seconds.
#086 |
On the origin of the unidentified $\gamma$-ray source in NGC 2071
Agostina Filócomo
1
;
Juan Facundo Albacete Colombo
1
;
Enrique Mestre
2
;
Leonardo Javier Pellizza
3
;
Jorge Ariel Combi
4
1 - Universidad Nacional de Río Negro.
2 - Institute of Space Science.
3 - Instituto de Astronomía y Física del Espacio.
4 - Instituto Argentino de Radioastronomía.
Resumen:
NGC 2071 is a star-forming region positionally correlated with three unidentified $\gamma$-ray sources detected by the \textit{Fermi} satellite telescope. According to preliminary models, T-Tauri stars could produce $\gamma$-ray emission under specific conditions. We performed a spectral and temporal analysis of the \textit{Fermi} data to determine whether the detected emission was caused by flares occurring in T-Tauri stars. We found that the $\gamma$-ray source can only be detected in the first two years of observations at energies above 100~GeV. In addition, a variability analysis reveals that the expected frequency of events is compatible with flare activity with a minimum X-ray energy of $5 \times 10^{37}~\text{erg}$. These observational results impose, for the first time, a substantial constraint on the energetic of flares in T-Tauri stars that could explain the origin of unknown $\gamma$-ray sources in star-forming regions.
#409 |
Massive Star Clusters as Galactic Accelerators of Cosmic Rays
Maria Victoria del Valle
1
1 - Instituto de Astronomia, Geofísica e Ciências Atmosféricas da Universidade de São Paulo (IAG/USP).
Resumen:
In recent years, massive stellar clusters have received renewed attention as possible contributors to the Galactic component of cosmic rays. The collective action of stellar winds forms superbubbles, which are large, multi-parsec structures. The interacting stellar winds supply large amounts of kinetic energy that could be used to accelerate cosmic rays up to very high energies. The particles interact with the surrounding material producing gamma rays. In this work we study the particle acceleration and interactions in super bubbles produced by the collective interactions of massive young stars. We model the gamma-ray emission expected from these interactions and constrain the production of cosmic rays. We also analyze the observability of the modeled sources by gamma-ray observatories.
12:30 - 14:30
LUNCH
15:20 - 16:00
COFFEE BREAK
16:00 - 17:30
B: Facilities, Technologies and Data Science
Surveys, Instruments and Facilities
Chair: Anthony Brown
#445 |
SCORPIO a new facility instrument for Gemini South
The Scorpio Team
1
;
Ruben Diaz
1
1 - Gemini Observatory, NSF$^\prime$s NOIRLab.
Resumen:
SCORPIO, the new Gen4\#3 facility instrument for the Gemini
South telescope, will provide imaging and spectroscopy in
eight wavelength
bands simultaneously from 0.4 to 2.2 microns. SCORPIO will be
extremely versatile in addressing fore$-$front science cases ranging
from Solar System studies to extragalactic astrophysics and will
play a leading role in Gemini follow$-$up of time$-$domain events
triggered by large$-$scale surveys. The instrument is currently
in its Assembly, Integration and Verification phase and is
expected to be commissioned at Cerro Pachon during semester
2025A and offered to the Gemini user community starting in
2025B. In this talk, I$^\prime$ll be reviewing SCORPIO$^\prime$s
history, motivation, and final design, describe the expected
performance in the context of its driving science cases,
and summarize how it will be integrated in the Gemini TDA
projects and operations.
#532 |
The LLAMA Observatory
Jacques R.D. Lepine
1
;
Ricardo F. Trindade
2
;
Danilo Zanella
3
;
Andrey Baryschev
4
;
Fatima Salete Correra
5
;
Marcos Aurelio Luqueze
6
;
Antonio Verri
5
;
Wesley Beccaro
5
;
Ciriaco Goddi
7
;
Tania Dominici
8
;
Cesar Strauss
9
;
Luiz Reitano
10
;
Guillermo G. de Castro
11
;
Jean Pierre Raulin
11
;
Paula Benaglia
12
;
Manuel Fernandez
12
;
Juan José Larrarte
12
;
Guillermo Gancio
12
;
Silvina Cichowolski
13
;
Carlos Valotto
14
;
Ricardo Finger Camus
15
;
Emiliano Rasztocky
12
;
Rodrigo Reeves
16
1 - IAG- Universidade de São Paulo.
2 - Universidade de São Paulo.
3 - IAG-Universidade de São Paulo.
4 - University of Groningen.
5 - Escola Politécnica Universidade de São Paulo.
6 - Escola Politécnica Universidade de São Paulo.
7 - IAG Universidade de São Paulo.
8 - INPE Instituto de Ciências Espaciais.
9 - INPE (Instituto Nacional de Ciências Espaciais).
10 - INPE (Instituto Ncional de Ciências Espaciais).
11 - Universidade Mackenzie.
12 - Instituto Argentino de Radioastronomia.
13 - IAFE (Instituto de Astronomia y Fisica del Espacio).
14 - CONICET Universidad de Cordoba.
15 - Das. -Universidad de Chile.
16 - CePia Universidad de Concepción.
Resumen:
The LLAMA Observatory, in the Argentinian Andes at 4800m altitude, in the Salta province, is a project of Argentina and Brazil, which started in 2014 with an agreement between FAPESP ( research foundation of Sao Paulo State), University of São Paulo, and MinCyt ( Ministry of Science and technology of Argentina. The expenses will be equally shared. The 12m diameter antenna was constructed by VERTEX Antennentechnik GmbH (Duisburg, Germany). The surface precision of the dish will reach 15 microns r.m.s. deviations from an ideal parabola, after a period of fine adjustments. The antenna will perform observations at mm and sub-mm radio waves, like the international ALMA interferometer. The LLAMA antenna will be equipped with two lateral Nasmith cabins, similarly to the APEX antenna. Initially, we will work with receivers band 5, band 6 and band 9 (band names of the ALMA observatory), constructed at NOVA Labs (University of Groningen, Holland). Brazil contributed to the acquisition of receivers and construction of sub-systems , like the optomechanical system to be installed inside the Nasmith and Cassegrain cabins, the cryogenics, and cryostat,where the receivers will be installed. and a system for holography.
The mounting of the antenna, which was slow in last years is going quite rapidly now, after Mincyt attributed to INVAP, a strong engineering and technological company, the task of mounting. It is predicted that the mounting will be concluded in March 2024, and the first light will happen 2 years later.
The main scientific uses will be in the following areas: Galaxy Formation in the Early Universe; Astrochemistry: molecular evolution of interstellar clouds; Identification of unknown lines; Extra-solar planets and proto-planetary disks; polarimetry of radio sources and of the Interstellar Medium; Solar Physics (few antennas at this frequency can be pointed towards the Sun, like LLAMA).
#520 |
Radio telescopes for Mexico and Latin America
Stan Kurtz
1
;
David Gale
2
1 - IRyA, UNAM.
2 - INAOE.
Resumen:
Inspired by similar efforts in Asia, Australia and Africa, we have
undertaken an effort in Mexico to convert a retired telecommunications
antenna into a radio telescope. The Tulancingo-1 antenna is a 32-meter
parabolic dish, located at the Tulancingo Earth Station in the Mexican
state of Hidalgo. When fully operational, we anticipate an operational
frequency range of 1 to 15 GHz, and possibly as high as 23 GHz. Here, we
describe the current state of the conversion project, mention several of
the many potential science applications of the telescope, and extrapolate
our experience to what might be achieved by a Latin American network of
radio telescopes, based on similarly converted antennas.
#421 |
What is this? WIT objects and serendipity in the VVV/VVVX survey
Dante Minniti
1
1 - UNAB/VO/UFSC.
Resumen:
The VVVX survey (VVV extended) have been monitoring the Galactic bulge and southern disk in the near-IR using the VISTA telescope at ESO Paranal Observatory for a dozen years. We have carried out massive searches for variable stars, resulting in the discovery of many many thousands of variable sources of all kinds (eclipsing binaries, RR Lyrae, Miras/LPVs, delta Scuti stars, classical Cepheids, type 2 Cepheids, novae, microlensing events, etc). Interestingly, some objects that defy classification have also been found within our database. These are called WIT objects (short for What Is This?). Upon closer inspection, in the end some of these WITs turn out to be observational glitches, or to fit into the previously known kinds of objects, but that are observed through extreme conditions like very high extinction. However, a few of them appear to be new astrophysical phenomena. I will discuss some specific cases of previously unclassified variable sources that have been discovered by the VVV near-IR survey. They a wide variety of extreme or rare astrophysical phenomena, including light echoes, eruptive YSOs, protostellar colissions, dusty novae, Tabby stars, eclipses by a dark disk, violently variable AGNs, etc. I will describe our searches and also the different follow-up observations that are needed to properly properly characterize these sources, and how to take into account serendipity in future surveys.
