Browsing by Author "Gibbs, A."

Now showing 1 - 6 of 6
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    Sixty 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....
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    The 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....
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    The First Optical Transient Discoveries from MLS (The Astronomer's Telegram, No.2318)
    (2009) Drake, A. J.; Djorgovski, S. G.; Mahabal, A. A.; Graham, M. J.; Williams, R.; Catelan, Marcio; Beshore, E. C.; Larson, S. M.; Boattini, A.; Gibbs, A.; Grauer, A.; Hill, R.; Kowalski, R.; Christensen, E.
    We report on the discovery of optical transients by the Catalina Real-time Transient Survey (CRTS) in data from the Catalina Sky Survey's 1.5m Mount Lemmon Survey (MLS) telescope. The transients were discovered between 2009-11-11 and 2009-11-24 UT and have the following parameters....
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    The pre-Nova light curve of CSS081007:030559+054715
    (2009) Drake, A. J.; Beshore, E. C.; Djorgovski, S. G.; Mahabal, A. A.; Graham, M. J.; Williams, R.; Catelan, Marcio; Larson, S. M.; Hill, R.; Gibbs, A.; Boattini, A.; Christensen, E.
    The Nova CSS081007:030559+054715 was discovered by the Catalina Real-time Transient Survey (CRTS) on Oct 07 2008 UT and followed photometrically with the Palomar-60 between Oct 9 and Dec 12 2008. It was first classified as a possible recurrent nova by Pejcha et al. (2008; ATEL#1825) and later as Oxygen/Neon nova by Prieto et al. (2008; ATel#1835). Beardmore et al. (2008; ATEL#1873) subsequently discovered significant X-ray emission and a 1.77 day period by monitoring it with SWIFT and Nelson et al. (2009; ATEL#1910) observed it with Chandra and found the object to exhibit a supersoft continuum superimposed with prominent emission lines. Goranskij and Metlova (2009; ATEL#1938) observed it optically in B,V and Rc between Dec. 3 2008 and Feb. 19 2009 and discovered two possible periods (1.694 and 0.6106 days). We have analyzed 117 pre-outburst CSS observations of the object taken on 34 nights between Oct 1 2005 and Mar 10 2008 UT. We find the the object exhibited variability well in excess of one magnitude during this time. However, we find no evidence for the post-outburst 1.77 day X-ray period signal observed by Beardmore et al. (2008; ATEL#1873) or the 0.6106 and 1.694 day optical periods observed by Goranskij and Metlova (2009; ATEL#1938). We find the best period for pre-outburst oscillations is 11.386 +/- 0.010 days. However, the data do not strongly constrain the periodic nature of the pre-outburst oscillations. On going CSS observations suggest that the Nova must not have begun the rapid decline noted by Goranskij and Metlova (2009; ATEL#1938) until after Jan 29th UT (rather the Jan. 22nd). Spectroscopic follow-up obtained with the SMARTs 1.5m telescope on Nov. 5th and is consistent with that of Prieto et al. (2008; ATel#1835).
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    The pre-Nova Lightcurve of KT Eri (Nova Eridani 2009)
    (2009) Drake, A. J.; Djorgovski, S. G.; Graham, M. J.; Mahabal, A. A.; Williams, R.; Wils, P.; Greaves, J.; Catelan, Marcio; Prieto, J.; Beshore, E. C.; Larson, S. M.; Boattini, A.; Gibbs, A.; Grauer, A.; Hill, R.; Kowalski, R.; Christensen, E.
    Here we report on historical observations of the pre-Nova source of KT Eri (Nova Eridani 2009). Following the detection of the possible Nova at mag 8.1 by Yamaoka et al. (2009, CBET#2050), we carried out a search of Catalina Sky Survey 0.7m data covering the location of this event. Photometry of the source was found with dates between 2005-01-17 and 2009-11-18 UT. The Nova was clearly seen in outburst in images taken on Nov.
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    Thirty 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.