Browsing by Author "Anguita, Timo"

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    Nine lensed quasars and quasar pairs discovered through spatially extended variability in Pan-STARRS
    (2024) Dux, Frederic; Lemon, Cameron; Courbin, Frederic; Neira, Favio; Anguita, Timo; Galan, Aymeric; Kim, Sam; Hempel, Maren; Hempel, Angela; Lachaume, Regis
    We present the proof of concept of a method for finding strongly lensed quasars using their spatially extended photometric variability through difference imaging in cadenced imaging survey data. We applied the method to Pan-STARRS, starting with an initial selection of 14 107 Gaia multiplets with quasar-like infrared colours from WISE. We identified 229 candidates showing notable spatially extended variability during the Pan-STARRS survey period. These include 20 known lenses and an additional 12 promising candidates for which we obtained long-slit spectroscopy follow-up. This process resulted in the confirmation of four doubly lensed quasars, four unclassified quasar pairs, and one projected quasar pair. Only three are pairs of stars or quasar + star projections. The false-positive rate accordingly is 25%. The lens separations are between 0.81 '' and 1.24 '', and the source redshifts lie between z = 1 :47 and z = 2 :46. Three of the unclassified quasar pairs are promising dual-quasar candidates with separations ranging from 6.6 to 9.3 kpc. We expect that this technique is a particularly e fficient way to select lensed variables in the upcoming Rubin-LSST, which will be crucial given the expected limitations for spectroscopic follow-up.
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    Optimization of the Observing Cadence for the Rubin Observatory Legacy Survey of Space and Time: A Pioneering Process of Community-focused Experimental Design
    (2022) Bianco, Federica B.; Ivezić, Željko; Jones, R. Lynne; Graham, Melissa L.; Marshall, Phil; Saha, Abhijit; Strauss, Michael A.; Yoachim, Peter; Ribeiro, Tiago; Anguita, Timo; Bauer, A. E.; Bauer, Franz E.; Bellm, Eric C.; Blum, Robert D.; Brandt, William N.; Brough, Sarah; Catelan, Márcio; Clarkson, William I.; Connolly, Andrew J.; Gawiser, Eric; Gizis, John E.; Hložek, Renée; Kaviraj, Sugata; Liu, Charles T.; Lochner, Michelle; Mahabal, Ashish A.; Mandelbaum, Rachel; McGehee, Peregrine; Neilsen, Eric H., Jr.; Olsen, Knut A. G.; Peiris, Hiranya V.; Rhodes, Jason; Richards, Gordon T.; Ridgway, Stephen; Schwamb, Megan E.; Scolnic, Dan; Shemmer, Ohad; Slater, Colin T.; Slosar, Anže; Smartt, Stephen J.; Strader, Jay; Street, Rachel; Trilling, David E.; Verma, Aprajita; Vivas, A. K.; Wechsler, Risa H.; Willman, Beth
    Vera C. Rubin Observatory is a ground-based astronomical facility under construction, a joint project of the National Science Foundation and the U.S. Department of Energy, designed to conduct a multipurpose 10 yr optical survey of the Southern Hemisphere sky: the Legacy Survey of Space and Time. Significant flexibility in survey strategy remains within the constraints imposed by the core science goals of probing dark energy and dark matter, cataloging the solar system, exploring the transient optical sky, and mapping the Milky Way. The survey's massive data throughput will be transformational for many other astrophysics domains and Rubin's data access policy sets the stage for a huge community of potential users. To ensure that the survey science potential is maximized while serving as broad a community as possible, Rubin Observatory has involved the scientific community at large in the process of setting and refining the details of the observing strategy. The motivation, history, and decision-making process of this strategy optimization are detailed in this paper, giving context to the science-driven proposals and recommendations for the survey strategy included in this Focus Issue....