DSpace Angular :: Browsing by Author "Djorgovski, S. G."

Browsing by Author "Djorgovski, S. G."

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A comprehensive view of a strongly lensedplanck-associated submillimeter galaxy.
(2012) Fu, Hai; Kim, Sam; Jullo, E.; Cooray, Asantha; Bussmann, R. S.; Ivison, R. J.; Pérez-Fournon, I.; Djorgovski, S. G.; Scoville, Nick Z.; Yan, L.; Riechers, D. A.
A Supernova Candidate from the Siding Spring Survey
(2010) Drake, A. J.; Djorgovski, S. G.; Mahabal, A. A.; Graham, M. J.; Williams, R.; Prieto, J.; Catelan , Marcio; Christensen, E.; McNaught, R.; Garradd, G.; Beshore, E. C.; Larson, S. M.
We report the discovery of the first supernova candidate from the Siding Spring Survey (SSS) by the Catalina Real-time Transient Survey (CRTS). The detection has the following details: <table border=1 width=650 align=center> <tr><th>ID</th><th>Disc. Date</th><th>RA</th><th>Dec</th><th>Disc. Mag</th></tr> <tr align=center><td><a href='http://crts.caltech.edu/ATEL/SSS/1005080151534122262.atel.html'> SSS100508:210144-143830</a></td><td> 2010-05-08 </td><td> 21:01:44.10 </td><td> -14:38:30.5 </td><td> 16.4</tr> </table> The host galaxy, 2MFGC 15924 (=PGC 187888), has redshift z=0.0275 (Jones et al....
A survey for dwarf galaxy remnants around 14 globular clusters in the outer halo
(2018) Sollima, A.; Delgado, D. Martinez; Munoz, R. R.; Carballo-Bello, J. A.; Valls-Gabaud, D.; Grebel, E. K.; Santana, F. A.; Cote, P.; Djorgovski, S. G.
An Updated Catalog of 4680 Northern Eclipsing Binaries with Algol-type Light-curve Morphology in the Catalina Sky Surveys
(2018) Papageorgiou, Athanasios; Catelan, Márcio; Christopoulou, Panagiota-Eleftheria; Drake, Andrew J.; Djorgovski, S. G.
CRTS: 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....
Detection of period variations of eclipsing binaries in the Catalina Sky Survey
(2021) Papageorgiou, Athanasios; Catelan, Márcio; Christopoulou, Panagiota-Eleftheria; Drake, Andrew J.; Djorgovski, S. G.
Discovery and Classification of Transients from CRTS-II
(2016) Drake, A. J.; Djorgovski, S. G.; Mahabal, A. A.; Graham, M. J.; Stern, D.; Catelan, Márcio; Christensen, E.; Larson, S. M.
Following on from the Catalina Real-time Transient Survey (CRTS), the CRTS-II project has begun to search for transients and highly variable sources. As with CRTS, all detections will be made public immediately following discovery....
Discovery 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....
Discovery 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.
Interacting supernovae and supernova impostors. LSQ13zm : an outburst heralds the death of a massive star
(2016) Tartaglia, L.; Pastorello, A.; Sullivan, M.; Baltay, C.; Rabinowitz, D.; Nugent, P.; Drake, A. J.; Djorgovski, S. G.; Gal-Yam, A.; Bauer, Franz Erik; Barsukova, E. A.; Goranskij, V. P.; Valeev, A. F.; Fatkhullin, T.; Schulze, S.; Mehner, A.; Fabrika, S.; Taubenberger, S.; Nordin, J.; Valenti, S.
Physical Parameters of Northern Eclipsing Binaries in the Catalina Sky Survey
(2019) Papageorgiou, Athanasios; Catelan, Márcio; Christopoulou, Panagiota-Eleftheria; Drake, Andrew J.; Djorgovski, S. G.
Results from the Catalina Real-time Transient Survey
(2009) Drake, Andrew J.; Djorgovski, S. G.; Mahabal, A. A.; Graham, M.; Williams, R.; Catelan, Marcio; Beshore, E.; Larson, S.; Christensen, E.
The Catalina Real-time Transient Survey (CRTS) is a collaborative effort between Caltech and LPL that uses data from Catalina Sky Survey's 0.7m Schmidt telescope to search for optical transients. This survey currently covers a total of 26,000 square degrees on the sky between declinations -30 and 70. Observations covering 1200 square degrees are taken 21 nights per lunation and reach magnitudes of 19 to 20. CRTS is sensitive to transients with timescales from minutes to years since images are taken in sequences separated by 10 minutes and past observations date back over four years. Transient classification is performed using follow up imaging and spectroscopy in combination with VO-enabled archival analysis of CSS and Palomar Quest synoptic datasets and DSS, 2MASS, SDSS, GALEX and UKIDSS surveys. To date more than 600 unique transients have been identified by CRTS. These include more than 200 newly discovered Supernovae, Cataclysmic Variables and Blazars. Initial results of note include in the discovery of hyper-luminous supernovae, as well as a high rate of supernovae associated with intrinsically faint galaxies. In the near future we expect to expand the survey area and depth by utilizing data from two additional operational Catalina Sky Survey telescopes. All CRTS transients are discovered and distributed openly within minutes of observation using VOEvent technology as well as html tables, RSS feeds and GoogleSky (from VOEventNet.org). Astronomers will soon be able to automatically select transients of particular interest by using the personalized event selection available via the SkyAlert system....
Results From The First Year Of The Catalina Real-time Transient Survey
(2009) Drake, Andrew J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Catelan, Marcio; Beshore, E.; Larson, S.; Christensen, E.
The Catalina Real-time Transient Survey (CRTS) is a collaborative effort between Caltech and LPL that uses data from Catalina Sky Survey's 0.76m Schmidt telescope to search for optical transients (OTs) varying by more than two magnitudes between past and current data. The survey covers 26,000 square degrees on the sky between declination -30 and 70 at Galactic latitudes |b| > 10 deg. Sequences of four observations are taken separated by 10 minutes and cover 1200 square degrees each night for 21 nights per lunation. Observations reach transients at unfiltered magnitudes of 19 to 20. To date more than 400 unique OTs have been identified by CRTS. These transients include more than 150 supernovae and dwarf novae, as well as UV Ceti flares, high proper motion stars, comets, Miras and currently unidentified transients. Classification is carried out using follow up imaging and spectroscopy in combination with VO-enabled archival analysis of CSS and Palomar Quest synoptic datasets and DSS, 2MASS, SDSS, GALEX and UKIDSS surveys. All candidate OTs are published within 5 mins of observation and are openly accessible as VOEvents, html tables and RSS feeds (from VOEventNet.org). As part of our public outreach program, the CRTS event stream is also published in the event layer of Google Sky....
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....
SN 2008jb: A "Lost" Core-collapse Supernova in a Star-forming Dwarf Galaxy at ~10 Mpc
(2012) Prieto, J. L.; Lee, J. C.; Drake, A. J.; McNaught, R.; Garradd, G.; Beacom, J. F.; Beshore, E.; Catelan, Marcio; Djorgovski, S. G.; Pojmanski, G.; Stanek, K. Z.; Szczygieł, D. M.
We present the discovery and follow-up observations of SN 2008jb, a core-collapse supernova in the southern dwarf irregular galaxy ESO 302-14 (MB = -15.3 mag) at 9.6 Mpc. This nearby transient was missed by galaxy-targeted surveys and was only found in archival optical images obtained by the Catalina Real-time Transient Survey and the All-Sky Automated Survey. The well-sampled archival photometry shows that SN 2008jb was detected shortly after explosion and reached a bright optical maximum, V max ~= 13.6 mag (M V, max ~= -16.5). The shape of the light curve shows a plateau of ~100 days, followed by a drop of ~1.4 mag in the V band to a slow decline with an approximate 56Co decay slope. The late-time light curve is consistent with 0.04 ± 0.01 M ⊙ of 56Ni synthesized in the explosion. A spectrum of the supernova obtained two years after explosion shows a broad, boxy Hα emission line, which is unusual for normal Type II-Plateau supernovae at late times. We detect the supernova in archival Spitzer and WISE images obtained 8-14 months after explosion, which show clear signs of warm (600-700 K) dust emission. The dwarf irregular host galaxy, ESO 302-14, has a low gas-phase oxygen abundance, 12 + log(O/H) = 8.2 (~1/5 Z ⊙), similar to those of the Small Magellanic Cloud and the hosts of long gamma-ray bursts and luminous core-collapse supernovae. This metallicity is one of the lowest among local (lsim 10 Mpc) supernova hosts. We study the host environment using GALEX far-UV, R-band, and Hα images and find that the supernova occurred in a large star formation complex. The morphology of the Hα emission appears as a large shell (R ~= 350 pc) surrounding the FUV and optical emission. Using the Hα-to-FUV ratio and FUV and R-band luminosities, we estimate an age of ~9 Myr and a total mass of ~2 × 105 M ⊙ for the star formation complex, assuming a single-age starburst. These properties are consistent with the expanding Hα supershells observed in many well-studied nearby dwarf galaxies, which are tell-tale signs of feedback from the cumulative effect of massive star winds and supernovae. The age estimated for the star-forming region where SN 2008jb exploded suggests a relatively high-mass progenitor star with an initial mass M ~ 20 M ⊙ and warrants further study. We discuss the implications of these findings in the study of core-collapse supernova progenitors. This paper includes data gathered with the 6.5 m Magellan telescope at Las Campanas Observatory, Chile....
Supernova 2010gu
(2010) McNaught, R. H.; Garradd, G.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan , Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.McNaught, R. H.; Garradd, G.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan , Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.McNaught, R. H.; Garradd, G.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan , Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.McNaught, R. H.; Garradd, G.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan , Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.McNaught, R. H.; Garradd, G.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan , Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.McNaught, R. H.; Garradd, G.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan , Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.McNaught, R. H.; Garradd, G.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan , Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.
Further to CBET 2387, R. H. McNaught and G. Garradd, Australian National University; A. J. Drake, S. G. Djorgovski, A. Mahabal, M. J. Graham, and R. Williams, California Institute of Technology; J. L. Prieto, Carnegie Observatories; M. Catelan, Pontificia Universidad Catolica de Chile; E. C. Beshore and S. M. Larson, Lunar and Planetary Laboratory, University of Arizona; and E. Christensen, Gemini Observatory, report the CRTS discovery of an apparent supernova in unfiltered Siding Spring Survey (SSS) images: SN 2010 UT R.A. (2000.0) Decl. Mag. Offset 2010gu Aug. 7.67 22 19 23.16 -36 58 24.5 18.0 7".0 E, 3".3 N Further SSS magnitudes for 2010gu: July 9.81, [19.5; Aug. 10.76, 17.9. The host galaxy, 2MASX J22192259-3658278, has redshift z = 0.056....
Supernova 2010hj in Pgc 67413
(2010) Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; McNaught, R. H.; Garradd, G.; Howerton, S.; Prieto, J. L.; Catelan , Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.
Report the discovery of an apparent supernova in unfiltered Siding Spring Survey (SSS) images: SN 2010 UT R.A. (2000.0) Decl. Mag. Offset 2010hj Aug. 4.61 21 49 09.84 -59 02 23.2 17.1 5".5 W, 8".2 S Nothing was visible at this position on an SSS image from 2009 Oct. 1.50 UT (limitiing mag 18.9), but 2010hj was detected again in SSS images on Aug. 29.59 (no magnitude provided). The host galaxy appears to be PGC 67413 = ESO 145-G16. Joseph Brimacombe, Cairns, Australia, reports that ten stacked 600-s CCD images (limiting magnitude 20) taken remotely with a 32-cm RCOS telescope (+ STL6K camera + clear filter) at the Macedon Ranges Observatory near Melbourne, Australia, on Aug. 29.727 show the new object to be at mag 18.3 and located approximately 7" west and 7" south of the presumed host-galaxy nucleus. Another stacked image (seven 1200-s frames; limiting magnitude 20), taken by Brimacombe on Sept. 2.636 with a 40-cm RCOS telescope (+ U16 camera + red filter) at the Coral Towers Observatory (Cairns), yields mag 18.6 for 2010hj; the Sept. 2 stacked image has been posted at the following website URL: http://www.flickr.com/photos/43846774@N02/4952444311/....
Supernova 2010iw near UGC 4570
(2010) Howerton, C.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan , Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.
Report the discovery by Howerton of an apparent supernova in public Catalina Sky Survey (CSS) images: SN 2010 UT R.A. (2000.0) Decl. Mag. Offset 2010iw Oct. 14.66 8 45 15.01 +27 49 21.8 16.4 12".9 W, 3".4 S Further magnitudes for 2010iw: June 11.16 UT, [19.0 (CSS); Oct. 17.50, 16.3 (Howerton, remotely with a 0.6-m LB-1 telescope, Rodeo, NM, U.S.A.). They note that the new object lies 5".4 east and 1".1 north from a galaxy seen in Sloan Digital Sky Survey images with measured redshift z = 0.109; the current luminosity of 2010iw appears too high for it to be a regular supernova associated with this distant galaxy. The host galaxy is thus is likely to be UGC 4570 (at redshift z = 0.0215)....
Supernova 2010jt
(2010) Howerton, S.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; McNaught, R. H.; Garradd, G.; Prieto, J. L.; Catelan , Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.
Report the discovery of an apparent supernova in Siding Spring Survey (SSS) images made public via the "Catalina Real-time Transient Survey" program: SN 2010 UT R.A. (2000.0) Decl. Mag. Offset 2010jt Nov. 6.57 23 43 41.24 -41 18 46.9 19.0 20".5 E, 29".6 N Further SSS magnitudes for 2010jt: Oct. 18.51 UT, [20.5 (co-added image); Nov. 7.50, 19.0. The likely host galaxy, 6dFGS gJ234339.4-411917, has redshift z = 0.053....
Supernova 2010kq in UGC 1769
(2010) Howerton, S.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan , Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.
Report the CRTS discovery of an apparent supernova in public images from the Catalina Sky Survey (CSS). SN 2010 UT R.A. (2000.0) Decl. Mag. Offset 2010kq Dec. 7.23 2 18 10.92 +37 05 42.4 18.3 0".3 E, 4".9 S After posting on the CBAT's unconfirmed-objects webpage, Markku Nissinen and Veli-Pekka Hentunen (Varkaus, Finland) report that their exposures (limiting mag R = 18.9; 3-sigma) taken on Dec. 9 remotely with a 51-cm f/6.8 GRAS011 Global-Rent-a-Scope (+ FLI ProLine PL-11002M camera) near Mayhill, NM, USA, yield position end figures 11s.05, 39".9 for 2010kq (which is 1".5 east and 6".1 south of the center of the galaxy UGC 1769); they note that nothing is visible at this position on a red Palomar Sky Survey F plate. Further CCD magnitude estimates for 2010kq (unfiltered unless otherwise noted): Nov. 15.20 UT, [19.5 (CSS); Dec. 9.088, R = 16.4 +/- 0.1 (Nissinen and Hentunen); 9.14, 16.4 (Howerton; remotely using the LB-1 0.6m telescope at Rodeo, NM, U.S.A.). Drake notes that the presumed host galaxy, UGC 1769, has redshift z = 0.027....

Browsing by Author "Djorgovski, S. G."

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