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We catalog the 443 bright supernovae discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN) in $2018-2020$ along with the 519 supernovae recovered by ASAS-SN and 516 additional $m_{peak}\leq18$ mag supernovae missed by ASAS-SN. Our statistical analysis focuses primarily on the 984 supernovae discovered or recovered in ASAS-SN $g$-band observations. The complete sample of 2427 ASAS-SN supernovae includes earlier $V$-band samples and unrecovered supernovae. For each supernova, we identify the host galaxy, its UV to mid-IR photometry, and the offset of the supernova from the center of the host. Updated light curves, redshifts, classifications, and host galaxy identifications supersede earlier results. With the increase of the limiting magnitude to $g\leq18$ mag, the ASAS-SN sample is roughly complete up to $m_{peak}=16.7$ mag and is $90\%$ complete for $m_{peak}\leq17.0$ mag. This is an increase from the $V$-band sample where it was roughly complete up to $m_{peak}=16.2$ mag and $70\%$ complete for $m_{peak}\leq17.0$ mag., Comment: 14 pages, 7 figures, 4 tables. Updated to reflect changes made in the published version. Tables containing the catalog data presented in this submission are included in machine-readable format as ancillary files

Full list of authors: Morgado, B. E.; Sicardy, B.; Braga-Ribas, F.; Desmars, J.; Gomes-Júnior, A. R.; Bérard, D.; Leiva, R.; Ortiz, J. L.; Vieira-Martins, R.; Benedetti-Rossi, G.; Santos-Sanz, P.; Camargo, J. I. B.; Duffard, R.; Rommel, F. L.; Assafin, M.; Boufleur, R. C.; Colas, F.; Kretlow, M.; Beisker, W.; Sfair, R.; Snodgrass, C.; Morales, N.; Fernández-Valenzuela, E.; Amaral, L. S.; Amarante, A.; Artola, R. A.; Backes, M.; Bath, K. -L.; Bouley, S.; Buie, M. W.; Cacella, P.; Colazo, C. A.; Colque, J. P.; Dauvergne, J. -L.; Dominik, M.; Emilio, M.; Erickson, C.; Evans, R.; Fabrega-Polleri, J.; Garcia-Lambas, D.; Giacchini, B. L.; Hanna, W.; Herald, D.; Hesler, G.; Hinse, T. C.; Jacques, C.; Jehin, E.; Jørgensen, U. G.; Kerr, S.; Kouprianov, V.; Levine, S. E.; Linder, T.; Maley, P. D.; Machado, D. I.; Maquet, L.; Maury, A.; Melia, R.; Meza, E.; Mondon, B.; Moura, T.; Newman, J.; Payet, T.; Pereira, C. L.; Pollock, J.; Poltronieri, R. C.; Quispe-Huaynasi, F.; Reichart, D.; de Santana, T.; Schneiter, E. M.; Sieyra, M. V.; Skottfelt, J.; Soulier, J. F.; Starck, M.; Thierry, P.; Torres, P. J.; Trabuco, L. L.; Unda-Sanzana, E.; Yamashita, T. A. R.; Winter, O. C.; Zapata, A.; Zuluaga, C. A.--This is an Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., Context. The Centaur (10199) Chariklo has the first ring system discovered around a small object. It was first observed using stellar occultation in 2013. Stellar occultations allow sizes and shapes to be determined with kilometre accuracy, and provide the characteristics of the occulting object and its vicinity. Aims. Using stellar occultations observed between 2017 and 2020, our aim is to constrain the physical parameters of Chariklo and its rings. We also determine the structure of the rings, and obtain precise astrometrical positions of Chariklo. Methods. We predicted and organised several observational campaigns of stellar occultations by Chariklo. Occultation light curves were measured from the datasets, from which ingress and egress times, and the ring widths and opacity values were obtained. These measurements, combined with results from previous works, allow us to obtain significant constraints on Chariklo's shape and ring structure. Results. We characterise Chariklo's ring system (C1R and C2R), and obtain radii and pole orientations that are consistent with, but more accurate than, results from previous occultations. We confirm the detection of W-shaped structures within C1R and an evident variation in radial width. The observed width ranges between 4.8 and 9.1 km with a mean value of 6.5 km. One dual observation (visible and red) does not reveal any differences in the C1R opacity profiles, indicating a ring particle size larger than a few microns. The C1R ring eccentricity is found to be smaller than 0.022 (3σ), and its width variations may indicate an eccentricity higher than ~0.005. We fit a tri-axial shape to Chariklo's detections over 11 occultations, and determine that Chariklo is consistent with an ellipsoid with semi-axes of 143.8-1.5+1.4, 135.2-2.8+1.4, and 99.1-2.7+5.4 km. Ultimately, we provided seven astrometric positions at a milliarcsecond accuracy level, based on Gaia EDR3, and use it to improve Chariklo's ephemeris. © B. E. Morgado et al. 2021., This work was carried out within the “Lucky Star” umbrella that agglomerates the efforts of the Paris, Granada and Rio teams, which is funded by the European Research Council under the European Community’s H2020 (ERC Grant Agreement No. 669416). This research made use of SORA, a python package for stellar occultations reduction and analysis, developed with the support of ERC Lucky Star and LIneA/Brazil, within the collaboration Rio-Paris-Granada teams. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Part of this research is suported by INCT do e-Universo, Brazil (CNPQ grants 465376/2014-2). Based in part on observations made at the Laboratório Nacional de Astrofísica (LNA), Itajubá-MG, Brazil. The data include observations taken by the MiNDSTEp team at the Danish 1.54 m telescope at ESO’s La Silla observatory” and “UGJ acknowledges funding from the European Union H2020-MSCA-ITN-2019 under grant no. 860470 (CHAMELEON) and from the Novo Nordisk Foundation Interdisciplinary Synergy Programme grant no. NNF19OC0057374. TRAPPIST-South is funded by the Belgian Fund for Scientific Research (Fond National de la Recherche Scientifique, FNRS) under the grant PDR T.0120.21. The authors acknowledge the use of Sonja Itting-Enke’s C14 telescope and the facilities at the Cuno Hoffmeister Memorial Observatory (CHMO). The following authors acknowledge the respective CNPq grants: BEM 150612/2020-6; FB-R 314772/2020-0; RV-M 304544/2017-f5, 401903/2016-8; JIBC 308150/2016-3 and 305917/2019-6; MA 427700/2018-3, 310683/2017-3, 473002/2013-2. G.B.R. acknowledges CAPES-FAPERJ/PAPDRJ grant E26/203.173/2016 and CAPES-PRINT/UNESP grant 88887.571156/2020-00, MA FAPERJ grant E-26/111.488/2013 and ARGJr FAPESP grant 2018/11239-8. J.L.O., P.S.-S., R.D., and N.M. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709), from Spanish project AYA2017-89637-R, and from FEDER. P.S.-S. acknowledges financial support by the Spanish grant AYA-RTI2018-098657-J-I00 “LEO-SBNAF” (MCIU/AEI/FEDER, UE). E. Jehin is a Belgian FNRS Senior Research Associate. R.S. and O.C.W. acknowledge FAPESP grant 2016/24561-0 and CNPq grant 305210/2018-1. T.C.H. acknowledges financial support from the National Research Foundation (NRF; No. 2019R1I1A1A01059609).

We present the discovery that ASASSN-14ko is a periodically flaring AGN at the center of the galaxy ESO 253-G003. At the time of its discovery by the All-Sky Automated Survey for Supernovae (ASAS-SN), it was classified as a supernova close to the nucleus. The subsequent six years of V- and g-band ASAS-SN observations reveal that ASASSN-14ko has nuclear flares occurring at regular intervals. The seventeen observed outbursts show evidence of a decreasing period over time, with a mean period of $P_0 = 114.2 \pm 0.4$ days and a period derivative of $\dot{P} = -0.0017\pm0.0003$. The most recent outburst in May 2020, which took place as predicted, exhibited spectroscopic changes during the rise and a had a UV bright, blackbody spectral energy distribution similar to tidal disruption events (TDEs). The X-ray flux decreased by a factor of 4 at the beginning of the outburst and then returned to its quiescent flux after ~8 days. TESS observed an outburst during Sectors 4-6, revealing a rise time of $5.60 \pm 0.05$ days in the optical and a decline that is best fit with an exponential model. We discuss several possible scenarios to explain ASASSN-14ko's periodic outbursts, but currently favor a repeated partial TDE. The next outbursts should peak in the optical on UT 2020-09-7.4$ \pm $1.1 and UT 2020-12-26.5$ \pm $1.4., Comment: 26 pages, 15 figures, 7 tables. Will be submitted to ApJ. The latest flare is currently ongoing, as we predicted

Context. Bright stellar positions are now known with an uncertainty below 1 mas thanks to Gaia DR2. Between 2019-2020, the Galactic plane will be the background of Jupiter. The dense stellar background will lead to an increase in the number of occultations, while the Gaia DR2 catalogue will reduce the prediction uncertainties for the shadow path. Aims. We observed a stellar occultation by the Galilean moon Europa (J2) and propose a campaign for observing stellar occultations for all Galilean moons. Methods. During a predicted period of time, we measured the light flux of the occulted star and the object to determine the time when the flux dropped with respect to one or more reference stars, and the time that it rose again for each observational station. The chords obtained from these observations allowed us to determine apparent sizes, oblatness, and positions with kilometre accuracy. Results. We present results obtained from the first stellar occultation by the Galilean moon Europa observed on 2017 March 31. The apparent fitted ellipse presents an equivalent radius of 1561.2 $\pm$ 3.6 km and oblatenesses 0.0010 $\pm$ 0.0028. A very precise Europa position was determined with an uncertainty of 0.8 mas. We also present prospects for a campaign to observe the future events that will occur between 2019 and 2021 for all Galilean moons. Conclusions. Stellar occultation is a suitable technique for obtaining physical parameters and highly accurate positions of bright satellites close to their primary. A number of successful events can render the 3D shapes of the Galilean moons with high accuracy. We encourage the observational community (amateurs included) to observe the future predicted events., Comment: 10 pages, 16 figures, 4 tables, A&A Letter doi:10.1051/0004-6361/201935500

We present the discovery and early evolution of ASASSN-19bt, a tidal disruption event (TDE) discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN) at a distance of $d\simeq115$ Mpc and the first TDE to be detected by TESS. As the TDE is located in the TESS Continuous Viewing Zone, our dataset includes 30-minute cadence observations starting on 2018 July 25, and we precisely measure that the TDE begins to brighten $\sim8.3$ days before its discovery. Our dataset also includes 18 epochs of Swift UVOT and XRT observations, 2 epochs of XMM-Newton observations, 13 spectroscopic observations, and ground data from the Las Cumbres Observatory telescope network, spanning from 32 days before peak through 37 days after peak. ASASSN-19bt thus has the most detailed pre-peak dataset for any TDE. The TESS light curve indicates that the transient began to brighten on 2019 January 21.6 and that for the first 15 days its rise was consistent with a flux $\propto t^2$ power-law model. The optical/UV emission is well-fit by a blackbody SED, and ASASSN-19bt exhibits an early spike in its luminosity and temperature roughly 32 rest-frame days before peak and spanning up to 14 days that has not been seen in other TDEs, possibly because UV observations were not triggered early enough to detect it. It peaked on 2019 March 04.9 at a luminosity of $L\simeq1.3\times10^{44}$ ergs s$^{-1}$ and radiated $E\simeq3.2\times10^{50}$ ergs during the 41-day rise to peak. X-ray observations after peak indicate a softening of the hard X-ray emission prior to peak, reminiscent of the hard/soft states in X-ray binaries., 23 pages, 14 figures, 5 tables. A machine-readable table containing the host-subtracted photometry presented in this manuscript is included as an ancillary file

We present results from three world-wide campaigns that resulted in the detections of two single-chord and one multi-chord stellar occultations by the plutino object (84922) 2003 VS2. From the single-chord occultations in 2013 and 2014 we obtained accurate astrometric positions for the object, while from the multi-chord occultation on 2014 November 7, we obtained the parameters of the best-fitting ellipse to the limb of the body at the time of occultation. We also obtained short-term photometry data for the body in order to derive its rotational phase during the occultation. The rotational light curve present a peak-to-peak amplitude of 0.141 ± 0.009 mag. This allows us to reconstruct the 3D shape of the body, with principal semi-axes of a = 313.8 ± 7.1 km, b = 265.5- + 9.8 8.8 km, and c = 247.3- + 43.6 26.6 km, which is not consistent with a Jacobi triaxial equilibrium figure. The derived spherical volume equivalent diameter of 548.3- + 44.6 29.5 km is about 5% larger than the radiometric diameter of 2003 VS2 derived from Herschel data of 523 ± 35 km, but still compatible with it within error bars. From those results we can also derive the geometric albedo (0.123- + 0.014 0.015) and, under the assumption that the object is a Maclaurin spheroid, the density r = 1400- + 300 1000 for the plutino. The disappearances and reappearances of the star during the occultations do not show any compelling evidence for a global atmosphere considering a pressure upper limit of about 1 microbar for a pure nitrogen atmosphere, nor secondary features (e.g., rings or satellite) around the main body. © 2019. The American Astronomical Society. All rights reserved., G.B.-R. is thankful for the support of the CAPES and FAPERJ/PAPDRJ (E26/203.173/2016) grant. Part of the research leading to these results has received funding from the European Research Council under the European Community's H2020 (2014-2020/ERC grant agreement No. 669416 >LUCKY STAR>). The research leading to these results has received funding from the European Union's Horizon 2020 Research and Innovation Programme, under grant agreement No. 687378 (SBNAF). P.S.-S. and J.L.O. acknowledge the financial support by the Spanish grant AYA-2017-84637-R and the Proyecto de Excelencia de la Junta de Andalucia J.A. 2012-FQM1776. P.S.-S., J.L.O., and R.D. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the >Center of Excellence Severo Ochoa> award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709). Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under program ID 094.C-0352. M. A. thanks CNPq (grants 427700/2018-3, 310683/2017-3, and 473002/2013-2) and FAPERJ (grant E-26/111.488/2013). J.I.B.C. acknowledges CNPq grant 308150/2016-3. R. V.-M. thanks grants: CNPq-304544/2017-5, 401903/2016-8, Faperj: PAPDRJ-45/2013, and E-26/203.026/2015. F.B.-R. acknowledges CNPq grant 309578/2017-5. E.F.-V. acknowledges UFC 2017 Preeminent Postdoctoral Program (P3). TRAPPIST-South is a project funded by the Belgian Fonds (National) de la Recherche Scientifique (F.R.S.-FNRS) under grant FRFC 2.5.594.09. F. E.J. is a FNRS Senior Research Associate. A.A.C. acknowledges support from FAPERJ (grant E-26/203.186/2016) and CNPq grants (304971/2016-2 and 401669/2016-5). B.M. thanks the CAPES/Cofecub-394/2016-05 grant. A.R.G.J. and R.S. thank the financial support of FAPESP (proc. 2018/11239-8, proc. 2011/08171-3, proc. 2016/24561-0). A. M. thanks Caisey Harlingten for the use of his 50 cm telescope. We thank V. Buso and R. Condori for the observation efforts.

The icy dwarf planet Makemake has projected axes of 1,430 ± 9 and 1,502 ± 45 km and a V-band geometric albedo larger than Pluto’s but smaller than Eris’s, with no global Pluto-like atmosphere. Makemake is thought to be the third-largest dwarf planet in our Solar System, a little smaller than Pluto and Eris, but until now knowledge of its size and albedo were only approximate. This paper reports the results of observations of the occultation of a faint star known as NOMAD 1181-0235723 by Makemake on 23 April 2011. The data confirm that Makemake is smaller than Pluto and Eris, with axes of 1,430±9 km and 1,502±45 km. Makemake's mean geometric albedo — the ratio of light reflected to light received — is intermediate between that of Pluto and that of Eris. All three are icy, making them among the most reflective objects in the Solar System. And the occultation light curves rule out the presence of a global Pluto-like atmosphere on Makemake, although the presence of dark terrain might imply the presence of a localized atmosphere. Pluto and Eris are icy dwarf planets with nearly identical sizes, comparable densities and similar surface compositions as revealed by spectroscopic studies1,2. Pluto possesses an atmosphere whereas Eris does not; the difference probably arises from their differing distances from the Sun, and explains their different albedos3. Makemake is another icy dwarf planet with a spectrum similar to Eris and Pluto4, and is currently at a distance to the Sun intermediate between the two. Although Makemake’s size (1,420 ± 60 km) and albedo are roughly known5,6, there has been no constraint on its density and there were expectations that it could have a Pluto-like atmosphere4,7,8. Here we report the results from a stellar occultation by Makemake on 2011 April 23. Our preferred solution that fits the occultation chords corresponds to a body with projected axes of 1,430 ± 9 km (1σ) and 1,502 ± 45 km, implying a V-band geometric albedo pV = 0.77 ± 0.03. This albedo is larger than that of Pluto, but smaller than that of Eris. The disappearances and reappearances of the star were abrupt, showing that Makemake has no global Pluto-like atmosphere at an upper limit of 4–12 nanobar (1σ) for the surface pressure, although a localized atmosphere is possible. A density of 1.7 ± 0.3 g cm−3 is inferred from the data.

We present results derived from the first multi-chord stellar occultations by the transneptunian object (50000) Quaoar, observed on 2011 May 4 and 2012 February 17, and from a single-chord occultation observed on 2012 October 15. If the timing of the five chords obtained in 2011 were correct, then Quaoar would possess topographic features (crater or mountain) that would be too large for a body of this mass. An alternative model consists in applying time shifts to some chords to account for possible timing errors. Satisfactory elliptical fits to the chords are then possible, yielding an equivalent radius Requiv = 555±2.5 km and geometric visual albedo pV = 0.109±0.007. Assuming that Quaoar is a Maclaurin spheroid with an indeterminate polar aspect angle, we derive a true oblateness of = 0.087+0.0268 −0.0175, an equatorial radius of 569+24 −17 km, and a density of 1.99 ± 0.46 g cm−3. The orientation of our preferred solution in the plane of the sky implies that Quaoar’s satellite Weywot cannot have an equatorial orbit. Finally, we detect no global atmosphere around Quaoar, considering a pressure upper limit of about 20 nbar for a pure methane atmosphere. Fil: Braga Ribas, F.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil; . Laboratoire d; Fil: Sicardy, B.. Laboratoire d; . Universite Pierre Et Marie Curie; Francia; Fil: Ortiz, J. L.. Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España; Fil: Lellouch, E.. Laboratoire d; Fil: Tancredi, G.. Observatorio Astronomico Los Molinos; Uruguay; Fil: Lecacheux, J.. Laboratoire d; Fil: Vieira Martins, R.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil; . L; . Universidade Federal Rural do Rio de Janeiro. Observatorio do Valongo; Brasil; Fil: Camargo, J. I. B.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil; Fil: Assafin, M.. Universidade Federal Rural do Rio de Janeiro. Observatorio do Valongo; Brasil; Fil: Behrend, R.. Observatoire de Geneve; Suiza; Fil: Vachier, F.. L; Fil: Colas, F.. L; Fil: Morales, N.. Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España; Fil: Maury, A.. San Pedro de Atacama Celestial Explorations, Chile; Fil: Emilio, M.. Universidad Stadual de Ponta Grossa; Brasil; Fil: Amorim, A.. Universidade Federal Da Santa Catarina; Brasil; Fil: Unda Sanzana, E.. Universidad de Antofagasta. Unidad de Astronomía; Chile; Fil: Roland, S.. Observatorio Astronomico Los Molinos; Uruguay; Fil: Bruzzone, S.. Observatorio Astronomico Los Molinos; Uruguay; Fil: Almeida, L. A.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil; Fil: Rodrigues, C. V.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil; Fil: Jacques, C.. Centro de Estudos Astronomicos de Minas Gerais; Brasil; Fil: Gil Hutton, Ricardo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - San Juan. Complejo Astronómico; Argentina Fil: Vanzi, L.. Pontificia Universidad Católica de Chile. Department of Electrical Engineering and Center of Astro-Engineering; Chile; Fil: Milone, A. C.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil; Fil: Schoenell, W.. Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España; . Universidade Federal Da Santa Catarina; Brasil; Fil: Salvo, R.. Observatorio Astronomico Los Molinos; Uruguay; Fil: Almenares, L.. Observatorio Astronomico Los Molinos; Uruguay; Fil: Jehin, E. Université de Liège. Institut d’Astrophysique; Belgica; Fil: Manfroid, J.. Université de Liège. Institut d’Astrophysique; Belgica; Fil: Sposetti, S.. Gnosca Observatory, Suiza; Fil: Tanga, P.. Observatoire de la Cote D; . Universite de Sophia Antipolis. Laboratoire Lagrange; Francia; Fil: Klotz, A.. Université Toulouse III “Paul Sabatier”. Observatoire Midi-Pyrénées. Institut de Recherche en Astrophysique et Planétologie; Francia; Fil: Frappa, E.. Euraster, Francia; Fil: Cacella, P.. Rede de Astronomia Observacional; Brasil; Fil: Colque, J. P.. Universidad de Antofagasta. Unidad de Astronomía; Chile; Fil: Neves, C.. Universidad Stadual de Ponta Grossa; Brasil; Fil: Alvarez, E. M.. Observatorio Los Algarrobos, Uruguay; Fil: Gillon, M.. Université de Liège. Institut d’Astrophysique; Belgica; Fil: Pimentel, E.. Centro de Estudos Astronomicos de Minas Gerais; Brasil; Fil: Giacchini, B.. Centro de Estudos Astronomicos de Minas Gerais; Brasil; Fil: Roques, F.. Laboratoire d; Fil: Widemann, T.. Laboratoire d; Fil: Magalhães, V. S.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil; Fil: Thirouin, A.. Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España; Fil: Duffard, Rene Damian. Centro Informático Científico de Andalucía; España; . Consejo Superior de Investigaciones Científicas. Instituto de Astrofísica de Andalucía; España; Fil: Leiva, R.. Pontificia Universidad Católica de Chile. Department of Electrical Engineering and Center of Astro-Engineering; Chile; Fil: Toledo, I.. Joint Atacama Large Millimeter/submillimeter Array Observatory; Chile; Fil: Capeche, J.. Observatorio Astronomico Los Molinos; Uruguay; Fil: Beisker, W.. International Occultation Timing Association European Section; Alemania; Fil: Pollock, J.. Appalachian State University. Department of Physics and Astronomy; Estados Unidos; Fil: Cedeno Montaña, C. E.. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; Brasil; Fil: Ivarsen, K. University of North Carolina. Physics and Astronomy Department; Estados Unidos; Fil: Reichart, D.. University of North Carolina. Physics and Astronomy Department; Estados Unidos; Fil: Haislip, J.. University of North Carolina. Physics and Astronomy Department; Estados Unidos; Fil: Lacluyze, A.. University of North Carolina. Physics and Astronomy Department; Estados Unidos