Início » Educação & Divulgação » Webinars » 2023
28/09 - 11:00 am
Valerio Carruba
Abstract ⓘ
Abstract
×Speaker
Valerio Carruba
Title
Deep learning modeling of g-type secular resonances (São Paulo State University)
Abstract
Linear secular resonances happen when there is a commensurability between the precession frequency of the pericenter, g, or longitude of the node, s, of an asteroid and a planet. Non-linear resonances are higher-order combinations of these frequencies. We studied the three most diffusive g-type non-linear secular resonances using Artificial Neural Networks. We identified a population of more than 2000 resonant objects in the g-g6, g-2g6+g5, and g-3g6+2g5 resonances. This allows the creation of Convolutional Neural Network models for the g-g6 and g-2g6+g5 resonance, able to predict the status of several thousands of asteroids in seconds. We identified the 12988 Tiffanykapler, 5507 Nijima, and 170776 2004 CA95 asteroid families among the resonant population, which have all estimated ages of less than 7 My. These are the three first-ever identified young families in resonant configurations of the studied resonances, which allows for setting limits on their original ejection velocity field. Collisional models of the main belt suggest that several more new asteroid families in such configurations will be likely discovered once the new data from the LSST survey will become available, allowing for a better understanding of the processes behind asteroid family formation.
Slides not available
14/09 - 11:00 am
Or Graur
Abstract ⓘ
Abstract
×Speaker
Or Graur
Title
Searching for transient treasures in galaxy spectra (University of Portsmouth)
Abstract
The Sloan Digital Sky Survey (SDSS) and other large-scale spectroscopic galaxy surveys collect hundreds of thousands of galaxy spectra. The collaborations behind these survey use their data mostly for cosmology and galaxy studies. In my talk, I will show how the same data can be used as transient surveys. Every now and again, a transient event, such as a supernova, will happen to go off in the center of the galaxy targeted for spectroscopy. Although this happens rarely (1 in 100,000 spectra), when the galaxy samples are large enough (in the millions), one can assemble transient samples large enough for cutting-edge science. I will show how my group has used both SDSS and the currently-active Dark Energy Spectroscopic Instrument (DESI) survey to study both supernovae and tidal disruption events.
Slides not available