Browsing by Author "Torrealba, G."
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- ItemDiscovery of a thin stellar stream in the SLAMS survey(2018) Jethwa, P.; Torrealba, G.; Navarrete, C.; Carballo-Bello, J. A.; de Boer, T.; Erkal, D.; Koposov, S. E.; Duffau, S.; Geisler, D.; Catelan, Márcio; Belokurov, V.
- ItemDiscovery of Thousands of RR Lyrae by the Catalina Surveys(2013) Drake, Andrew J.; Djorgovski, S. G.; Catelan, Márcio; Torrealba, G.; Graham, M.; Mahabal, A. A.; Donalek, C.; Prieto, J.; McNaught, R.; Larson, S. M.; Christensen, E.; Beshore, E. C.We have performed an extensive search for RR Lyrae among the 500 million sources observed by the Catalina Surveys. We detect 23,000 type-ab RR Lyrae (of which 18,700 are new discoveries) from a region spanning 3/4 of the sky. By combining calibrated Catalina photometry with RR Lyrae absolute magnitude estimates, we derive accurate distances and investigate the spatial distribution of structures within the Galactic halo. We identify hundreds of new RR Lyrae belonging to the Sagittarius tidal streams system and compare their observed properties with predictions from existing N-body models. We discover significant evidence that firmly establishes the existence of a tidal stream reaching Galactocentric distances beyond 100 kpc. This stream remains to be explained by any Sagittarius model. For 1,500 of the RR Lyrae we find matches with targets observed by past SDSS spectroscopic surveys. Combining the radial velocities and metallicity estimates from the SDSS spectra, with photometric distances, we investigate the kinematics and abundances of halo tidal stream populations....
- ItemDiscovery of ~9000 new RR Lyrae in the southern Catalina surveys(2015) Torrealba, G.; Catelan, Márcio; Drake, A. J.; Djorgovski, S. G.; McNaught, R. H.; Belokurov, V.; Koposov, S.M.; Graham, M. J.; Mahabal, A.; Larson, S.; Christensen, E.
- ItemNear-Field Cosmology with RR Lyrae Variable Stars: a first view of substructure in the southern sky(2016) Navarrete, C.; Duffau, S.; Vivas, A. K.; Catelan, Márcio; Hajdu, G.; Torrealba, G.; Cortés, C.; Belokurov, V.; Koposov, S.; Drake, A. J.We present the current status of the spectroscopic follow-up of a large number of RR Lyrae (RRL) halo overdensity candidates recently found by Torrealba et al. (2015) using southern-hemisphere data from the Catalina Real-time Transient Survey (CRTS). Characterizing the individual RRL stars in these overdensities is crucial to confirm them as real halo substructures. Low-resolution spectra have been obtained for RRL stars in 11 different overdensities, using the SOAR and Magellan telescopes. Radial velocities and metallicities have been derived so far for 123 and 99 RRL stars, respectively....
- ItemSixty Thousand Periodic Variables from the Catalina Surveys(2014) Drake, Andrew J.; Graham, M.; Djorgovski, S. G.; Catelan, Marcio; Mahabal, A. A.; Prieto, J.; Donalek, C.; Christensen, E. J.; Larson, S. M.; Boattini, A.; Gibbs, A.; Grauer, A. D.; Hill, R.; Kowalski, R.; Johnson, J.; Shelly, F.; Torrealba, G.We have performed an in-depth search for periodic variable stars within the photometry from the Catalina Surveys Data Releases. Our analysis reveals ~40,000 new periodic variable stars with brightness ranging from V=11 to 20, from a region covering ~20,000 square degrees on the sky. Each source is classified based on lightcurve morphology and multi-color photometry from WISE and SDSS. The variable stars discovered include eclipsing binaries, such as Algol, beta Lyrae, W UMa and WD+dM types, and pulsators including delta Scuti's, SX Phe, LPVs, RR Lyrae and Cepheids. We combine these sources with type-ab RR Lyrae from our prior analysis to produce a periodic variable catalog containing 60,000 stars. Using ~5,500 optical spectra from SDSS DR10 we determine the metallicities, surface gravities and radial velocities of the major types. The photometry, classifications and periods will all be made publicly available through the Catalina Surveys data release website....
- ItemTHE CATALINA SURVEYS PERIODIC VARIABLE STAR CATALOG(2014) Drake, A.; Graham, M.; Djorgovski, S.; Mahabal, A.; Catelan, Márcio; García Alvarez, D.; Donalek, C.; Torrealba, G.
- ItemThe Catalina Surveys Southern periodic variable star catalogue(2017) Drake, A. J.; Djorgovski, S. G.; Catelan, Márcio; Graham, M. J.; Mahabal, A. A.; Larson, S.; Christensen, E.; Torrealba, G.; Beshore, E.; McNaught, R. H.; Garradd, G.; Belokurov, V.; Koposov, S. E.
- ItemULTRA-SHORT PERIOD BINARIES FROM THE CATALINA SURVEYS(2014) Drake, A.; Djorgovski, S.; García Alvarez, D.; Graham, M.; Catelan, Márcio; Mahabal, A.; Donalek, C.; Torrealba, G.