Browsing by Author "Donalek, C."
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- ItemCRTS: An Open Optical Transient Survey(2011) Drake, Andrew J.; Djorgovski, S. G.; Mahabal, A.; Williams, R.; Graham, M. J.; Donalek, C.; Prieto, J. L.; Catelan, Márcio; Beshore, E.; Larson, S.; Christensen, E.The Catalina Real-time Transient Survey (CRTS) is an open optical transient survey that covers 3/4 of the entire sky in a search of transient astrophysical phenomena occurring on timescales of minutes to years. Observational data is derived from the three telescopes of the Catalina Sky Survey which cover up to 2,500 square degrees of sky each night. CRTS has so far discovered more that 2000 transient sources including 600 supernovae, 500 dwarf novae and more than 100 Blazars and UV Ceti variables. All data is processed within minutes of observation and discoveries are openly distributed using SkyAlert and VOEvent technologies as well as iPhone, html tables, RSS and Twitter feeds. Events are classified utilizing data from virtual observatory enabled archives, machine learning, and collaborative Citizen science....
- 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....
- 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....
- ItemSupernova 2011ke(2013) Drake, A. J.; Djorgovski, S. G.; Mahabal, A. A.; Graham, M. J.; Williams, R.; Donalek, C.; Prieto, J.; Catelan, Marcio; Larson, S. M.; Christensen, E.; Inserra, C.; Smartt, S. J.; Fraser, M.; Young, D.; Smith, K.; Wright, D.; Kotak, R.; McCrum, M.; Magill, L.; Chen, T. -W.; Pastorello, A.; Benetti, S.; Valenti, S.; Bresolin, F.; Kudritzki, R.; Tonry, J.; Magnier, E.; Huber, M.; Chambers, K.; Kaiser, N.; Morgan, J.; Burgett, W.; Heasley, J.; Sweeney, W.; Waters, C.; Flewelling, H.; Stubbs, C.; Price, P. A.; Sollerman, J.; Taddia, F.; Ergon, M.; Leloudas, G.; Taubenberger, S.Report the Catalina Real-time Transient Survey discovery of an apparent supernova in V-band Catalina Sky Survey (CSS) images: SN 2011 UT R.A. (2000.0) Decl. Mag. 2011ke Apr. 25.4 13 50 57.78 +26 16 42.4 17.6 Nothing is visible at this position on a CSS image from 2011 Mar. 16 UT (limiting mag 19.5). C. Inserra, S. J. Smartt, M. Fraser, D. Young, K. Smith, D. Wright, R. Kotak, M. McCrum, L. Magill, and T.-W. Chen, Queen's University, Belfast; A. Pastorello and S. Benetti, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica; S. Valenti, Las Cumbres Observatory Global Telescope and University of California at Santa Barbara; F. Bresolin, R. Kudritzki, J. Tonry, E. Magnier, M. Huber, K. Chambers, N. Kaiser, J. Morgan, W. Burgett, J. Heasley, W. Sweeney, C. Waters, and H. Flewelling, University of Hawaii; C. Stubbs, Harvard University; P. A. Price, Princeton University; J. Sollerman, F. Taddia, and M. Ergon, Oscar Klein Centre, Stockholm; G. Leloudas, Dark Cosmology Centre, Copenhagen; and S. Taubenberger, Max-Planck-Institut fuer Astrophysik, Garching, report that they obtained a spectrogram of 2011ke on 2011 May 21 UT with the Telescopio Nazionale Galileo (+ DOLORES). The spectrum shows the clear presence of emission from the host galaxy of [O II], [O III], H-beta, and H-alpha. (The host galaxy is also clearly seen in images obtained via the Canada-France-Hawaii Telescope and the Sloan Digital Sky Survey.) A good match is obtained with the spectrum of SN 2010gx (cf. CBET 2413), a super-luminous type-Ic supernova, at a week after maximum light....
- 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 First Data Release of the Catalina Surveys(2012) Drake, Andrew J.; Beshore, E.; Djorgovski, S. G.; Larson, S.; Boattini, A.; Catelan, Marcio; Christensen, E.; Donalek, C.; Gibbs, A.; Graham, M.; Grauer, A.; Hill, R.; Kowalski, R.; Mahabal, A.; Prieto, J. L.; Williams, R.The Catalina Surveys consists of the Catalina Sky Survey (CSS) and the Catalina Real-time Transient Survey (CRTS). These two surveys work synergistically to extract the maximum scientific return from the data gathered by Catalina telescopes. In order to further facility the wealth of time-domain science that is possible with this data, the Catalina Surveys are now releasing Catalina Schmidt telescope photometry for 200 million objects. Each source has been measured over a period of six years and comes from a 24,000 square degree region between declination -30 and +70 degrees (with 10 degree avoidance of the galactic plane). On average each location in the data release has been observed more than 200 times to a depth of V=19.5. We will provide the details of the open-access data services as well as future data releases and recent discoveries....
- ItemThirty Three New SNe from CRTS(2011) Drake, A. J.; Mahabal, A. A.; Djorgovski, S. G.; Graham, M. J.; Williams, R.; Donalek, C.; Myers, A.; Prieto, J.; Catelan, Marcio; Christensen, E.; Beshore, E. C.; Larson, S. M.; Grauer, A.; Boattini, A.; Gibbs, A.; Hill, R.; Kowalski, R.Further to ATel#3188, we report the CRTS discovery of 33 new supernova candidates in data from the Catalina Sky Survey taken between 2011-02-23 and 2011-03-10 UT.
- ItemThree blue optical transients from CRTS(2011) Drake, A. J.; Djorgovski, S. G.; Mahabal, A. A.; Graham, M. J.; Williams, R.; Donalek, C.; Prieto, J.; Catelan, Marcio; Christensen, E.; Beshore, E. C.; Larson, S. M.; McNaught, R. H.During the course of the CRTS survey, observations of poorly understood transient sources were undertaken with the Palomar 5m+DBSP on May 7 and May 8 UT. In addition to many SNe (ATEL#3340), three events were found exhibiting very blue continua.
- 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.