Browsing by Author "Silva-Farfan, Javier"

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    Multiscale Stamps for Real-time Classification of Alert Streams
    (IOP Publishing Ltd., 2023) Reyes-Jainaga, Ignacio; Forster, Francisco; Muñoz Arancibia, Alejandra M.; Cabrera-Vives, Guillermo; Bayo, Amelia; Bauer, Franz Erik; Arredondo, Javier; Reyes, Esteban; Pignata, Giuliano; Mourao, A. M.; Silva-Farfan, Javier; Galbany, Lluis; Alvarez, Alex; Astorga, Nicolas; Castellanos, Pablo; Gallardo, Pedro; Moya, Alberto; Rodriguez, Diego
    In recent years, automatic classifiers of image cutouts (also called "stamps") have been shown to be key for fast supernova discovery. The Vera C. Rubin Observatory will distribute about ten million alerts with their respective stamps each night, enabling the discovery of approximately one million supernovae each year. A growing source of confusion for these classifiers is the presence of satellite glints, sequences of point-like sources produced by rotating satellites or debris. The currently planned Rubin stamps will have a size smaller than the typical separation between these point sources. Thus, a larger field-of-view stamp could enable the automatic identification of these sources. However, the distribution of larger stamps would be limited by network bandwidth restrictions. We evaluate the impact of using image stamps of different angular sizes and resolutions for the fast classification of events (active galactic nuclei, asteroids, bogus, satellites, supernovae, and variable stars), using data from the Zwicky Transient Facility. We compare four scenarios: three with the same number of pixels (small field of view with high resolution, large field of view with low resolution, and a multiscale proposal) and a scenario with the full stamp that has a larger field of view and higher resolution. Compared to small field-of-view stamps, our multiscale strategy reduces misclassifications of satellites as asteroids or supernovae, performing on par with high-resolution stamps that are 15 times heavier. We encourage Rubin and its Science Collaborations to consider the benefits of implementing multiscale stamps as a possible update to the alert specification.
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    Physical Properties of Type II Supernovae Inferred from ZTF and ATLAS Photometric Data
    (2024) Silva-Farfan, Javier; Forster, Francisco; Moriya, Takashi J.; Hernandez-Garcia, L.; Arancibia, A. M. Munoz; Sanchez-Saez, P.; Anderson, Joseph P.; Tonry, John L.; Clocchiatti, Alejandro
    We report an analysis of a sample of 186 spectroscopically confirmed Type II supernova (SN) light curves (LCs) obtained from a combination of Zwicky Transient Facility (ZTF) and Asteroid Terrestrial-impact Last Alert System observations. We implement a method to infer physical parameters from these LCs using hydrodynamic models that take into account the progenitor mass, the explosion energy, and the presence of circumstellar matter (CSM). The CSM is modeled via the mass-loss rate, wind acceleration at the surface of the progenitor star with a beta velocity law, and the CSM radius. We also infer the time of explosion, attenuation (A (V) ), and the redshift for each SN. Our results favor low-mass progenitor stars (M (ZAMS )< 14 M-circle dot) with a dense CSM ( M > 10(-3) M-circle dot yr(-1), CSM radius similar to 10(15) cm, and beta > 2). Additionally, we find that the redshifts inferred from the SN LCs are significantly more accurate than those inferred using the host galaxy photometric redshift, suggesting that this method could be used to infer more accurate host galaxy redshifts from large samples of Type II SNe in the LSST era. Lastly, we compare our results with similar works from the literature.