Browsing by Author "Lira, Paulina"
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- ItemAlert Classification for the ALeRCE Broker System: The Anomaly Detector(IOP Publishing Ltd, 2023) Pérez-Carrasco, Manuel; Cabrera-Vives, Guillermo; Hernández-García, Lorena; Forster, F.; Sanchez-Saez, Paula; Muñoz Arancibia, Alejandra M.; Arredondo, Javier; Astorga, Nicolas; Bauer, Franz Erik; Bayo, Amelia; Catelan, Marcio; Dastidar, Raya; Estevez, P. A.; Lira, Paulina; Pignata, GiulianoAstronomical broker systems, such as Automatic Learning for the Rapid Classification of Events (ALeRCE), are currently analyzing hundreds of thousands of alerts per night, opening up an opportunity to automatically detect anomalous unknown sources. In this work, we present the ALeRCE anomaly detector, composed of three outlier detection algorithms that aim to find transient, periodic, and stochastic anomalous sources within the Zwicky Transient Facility data stream. Our experimental framework consists of cross-validating six anomaly detection algorithms for each of these three classes using the ALeRCE light-curve features. Following the ALeRCE taxonomy, we consider four transient subclasses, five stochastic subclasses, and six periodic subclasses. We evaluate each algorithm by considering each subclass as the anomaly class. For transient and periodic sources the best performance is obtained by a modified version of the deep support vector data description neural network, while for stochastic sources the best results are obtained by calculating the reconstruction error of an autoencoder neural network. Including a visual inspection step for the 10 most promising candidates for each of the 15 ALeRCE subclasses, we detect 31 bogus candidates (i.e., those with photometry or processing issues) and seven potential astrophysical outliers that require follow-up observations for further analysis.
- ItemClustering of Intermediate-Luminosity X-Ray-Selected Active Galactic Nuclei at z ~ 3.(2008) Francke Henríquez, Harold Johanns Phillippe; Treister, Ezequiel; Gawiser, Eric.; Lira, Paulina; Virani, Shanil; Cardamone, Carie; Urry, C. M.; van Dokkum, Pieter; Quadri, R.
- ItemHeavily Obscured AGN in Star-Forming Galaxies at z sime 2.(2009) Treister, Ezequiel; Cardamone, Carolin N.; Schawinski, Kevin; Urry, C. Meg; Gawiser, Eric.; Virani, Shanil; Lira, Paulina; Kartaltepe, Jeyhan; Damen, Maaike; Taylor, EN.; Le Floc'H e; Justham, Stephen; Koekemoer, Anton M.
- ItemLyα emitting Galaxies at z = 2.1 : Stellar Masses, Dust, and Star Formation Histories from Spectral Energy Distribution Fitting.(2011) Guaita, Lucía; Padilla, Nelson; Treister, Ezequiel; Acquaviva, Viviana; Gawiser, Eric; Bond, Nicholas A.; Ciardullo, Robin; Kurczynski, Peter; Gronwall, Caryl; Lira, Paulina; Schawinski, Kevin
- ItemMid-Infrared Properties and Color Selection for X-Ray-Detected Active Galactic Nuclei in the MUSYC Extended Chandra Deep Field-South.(2008) Cardamone, Carolin N.; Treister, Ezequiel; Urry, C. Meg; Damen, Maaike; van Dokkum, Pieter; Labbé, Ivo; Virani, Shanil N.; Lira, Paulina; Gawiser, Eric
- ItemOptical Spectroscopy of X-Ray Sources in the Extended Chandra Deep Field South(2009) Treister, Ezequiel; Virani, Shanil; Gawiser, Eric.; Urry, C. Megan; Lira, Paulina; Francke Henríquez, Harold Johanns Phillippe; Blanc, Guillermo; Cardamone, Carolin N.; Damen, Maaike; Taylor, Edward N.; Schawinski, Kevin
- ItemThe dust covering factor in active galactic nuclei(2016) Stalevski, Marko; Ricci, Claudio; Ueda, Yoshihiro; Lira, Paulina; Fritz, Jacopo; Baes, Maarten
- ItemThe Hunt for Red Quasars: Luminous Obscured Black Hole Growth Unveiled in the Stripe 82 X-Ray Survey(2017) LaMassa, Stephanie M.; Lira, Paulina; Treister, Ezequiel; Glikman, Eilat; Brusa, Marcella; Rigby, Jane R.; Ananna, Tonima; Stern, Daniel.; Urry, C. Megan; Salvato, M.; Alexandroff, Rachael
- ItemThe Multiwavelength Survey by Yale-Chile (MUSYC): Wide K-Band Imaging, Photometric Catalogs, Clustering, and Physical Properties of Galaxies at z ~ 2(2008) Blanc, Guillermo A.; Lira, Paulina; Barrientos, L. Felipe; Aguirre, Paula; Francke, Harold; Taylor, Edward N.; Quadri, Ryan; Marchesini, Danilo; Infante, Leopoldo; Gawiser, Eric; Hall, Patrick B.; Willis, Jon P.; Herrera, David; Maza, José; MUSYC Collaboration
- ItemThe Physical Nature of Lyα-emitting Galaxies at z = 3.1(2006) Gawiser, Eric.; Blanc, Guillermo; Francke Henríquez, Harold Johanns Phillippe; Infante Lira, Leopoldo; Lira, Paulina; Treister, Ezequiel; van Dokkum, Pieter G.; Gronwall, Caryl; Ciardullo, R.; Castander, Francisco J.; Feldmeier, John J.; Franx, Marijn
- ItemThe QUEST–La Silla AGN Variability Survey(2015) Cartier, Régis; Lira, Paulina; Coppi, Paolo; Sánchez, Paula; Arévalo, Patricia; Bauer, Franz Erik; Rabinowitz, David; Zinn, Robert; Muñoz, Ricardo R.; Meza, Nicolás