Examinando por Autor "Galbany, Lluís"

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    First Release of High-redshift Superluminous Supernovae from the Subaru HIgh-Z SUpernova CAmpaign (SHIZUCA). II. Spectroscopic Properties
    (Astrophysical Journal, Supplement Series, 2019-04) Curtin, Chris; Cooke, Jeff; Curtin, Chris; Cooke, Jeff; Moriya, Takashi J.; Tanaka, Masayuki; Quimby, Robert M.; Bernard, Stephanie R.; Galbany, Lluís; Jiang, Ji-an; Lee, Chien-Hsiu; Maeda, Keiichi; Morokuma, Tomoki; Nomoto, Ken’ichi; Pignata, Giuliano; Pritchard, Tyler; Suzuki, Nao; Takahashi, Ichiro; Tanaka, Masaomi; Tominaga, Nozomu; Yamaguchi, Masaki; Yasuda, Naoki
    We present Keck spectroscopic observations of three probable high-redshift superluminous supernovae (SLSNe) from the Subaru HIgh-Z sUpernova CAmpaign (SHIZUCA), confirming redshifts of 1.851, 1.965, and 2.399. The host galaxies were selected for transient monitoring from multiband photometric redshifts. The supernovae are detected during their rise, and the classically scheduled spectra are collected near maximum light. The rest-frame far-ultraviolet (∼1000-2500 ) spectra include a significant host galaxy flux contribution, and we compare our host-galaxy-subtracted spectra to UV-luminous SNe from the literature. While the signal-to-noise ratios of the spectra presented here are sufficient for redshift confirmation, supernova spectroscopic type confirmation remains inconclusive. The success of the first SHIZUCA Keck spectroscopic follow-up program demonstrates that campaigns such as SHIZUCA are capable of identifying high-redshift SLSNe with sufficient accuracy, speed, and depth for rapid, well-cadenced, and informative follow-up.
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    Multiscale Stamps for Real-time Classification of Alert Streams
    (American Astronomical Society, 2023-08) Reyes-Jainaga, Ignacio; Förster, Francisco; Muñoz Arancibia, Alejandra M.; Cabrera-Vives, Guillermo; Bayo, Amelia; Bauer, Franz E.; Arredondo, Javier; Reyes, Esteban; Pignata, Giuliano; Mourão A.M.; Silva-Farfán, Javier; Galbany, Lluís; Álvarez, Alex; Astorga, Nicolás; Castellanos, Pablo; Gallardo, Pedro; Moya, Alberto; Rodríguez, 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. © 2023. The Author(s). Published by the American Astronomical Society.