Browsing by Author "Prieto, J."

Now showing 1 - 12 of 12
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    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....
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    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....
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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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    Supernova 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....
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    The origin of spin in galaxies: clues from simulations of atomic cooling haloes
    (2015) Prieto, J.; Jiménez, R.; Haiman, Z.; González Reyes, Roberto
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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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    THE. TDE. ASASSN-14li AND. ITS. HOST. RESOLVED. AT. PARSEC. SCALES. WITH. THE. EVN
    (2016) Romero, C.; Prieto, J.; Xian, Chen; Kochanek, C.; Dong, S.; Holoien, T.; Stanek, K.; Liu, F.
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    Thirty Recent SN Candidates from CRTS
    (2012) Drake, A. J.; Djorgovski, S. G.; Mahabal, A. A.; Graham, M. J.; Williams, R.; Prieto, J.; Catelan, Marcio; Christensen, E.; Larson, S. M.; Beshore, E. C.
    Further to ATel#4137, below we report the discovery of 30 supernova candidates by CRTS in Catalina Sky Survey data taken between 2012-09-13 and 2012-10-06 UT.
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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.
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    Three 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.
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    Three-dimensional simulations of clump formation in stellar wind collisions
    (OUP, 2020) Calderón Espinoza, Diego Nicolás; Cuadra Stipetich, Jorge Rodrigo; Schartmann, M.; Burkert, A.; Prieto, J.; Russell, Christopher M. P.
    The inner parsec of our Galaxy contains tens of Wolf–Rayet stars whose powerful outflows are constantly interacting while filling the region with hot, diffuse plasma. Theoretical models have shown that, in some cases, the collision of stellar winds can generate cold, dense material in the form of clumps. However, their formation process and properties are not well understood yet. In this work, we present, for the first time, a statistical study of the clump formation process in unstable wind collisions. We study systems with dense outflows ( ∼10−5 M⊙ yr−1 ), wind speeds of 500– 1500 km s−1 , and stellar separations of ∼20– 200 au . We develop three-dimensional high-resolution hydrodynamical simulations of stellar wind collisions with the adaptive-mesh refinement grid-based code ramses. We aim at characterizing the initial properties of clumps that form through hydrodynamic instabilities, mostly via the non-linear thin-shell instability (NTSI). Our results confirm that more massive clumps are formed in systems whose winds are close to the transition between the radiative and adiabatic regimes. Increasing either the wind speed or the degree of asymmetry increases the dispersion of the clump mass and ejection speed distributions. Nevertheless, the most massive clumps are very light (∼10 −3 – 10−2 M⊕ ), about three orders of magnitude less massive than theoretical upper limits. Applying these results to the Galactic Centre, we find that clumps formed through the NTSI should not be heavy enough either to affect the thermodynamic state of the region or to survive for long enough to fall on to the central supermassive black hole.