DSpace Angular :: Browsing by Author "Jorgensen, U. G."

Browsing by Author "Jorgensen, U. G."

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An analysis of binary microlensing event OGLE-2015-BLG-0060
(2019) Tsapras, Y.; Cassan, A.; Ranc, C.; Bachelet, E.; Street, R.; Udalski, A.; Hundertmark, M.; Bozza, V.; Beaulieu, J. P.; Rabus, Markus; Marquette, J. B.; Euteneuer, E.; Bramich, D. M.; Dominik, M.; Jaimes, R. F.; Horne, K.; Mao, S.; Menzies, J.; Schmidt, R.; Snodgrass, C.; Steele, I. A.; Wambsganss, J.; Mroz, P.; Szymanski, M. K.; Soszynski, I.; Skowron, J.; Pietrukowicz, Pawel; Kozlowski, S.; Poleski, R.; Ulaczyk, K.; Pawlak, M.; Jorgensen, U. G.; Skottfelt, J.; Popovas, A.; Ciceri, S.; Korhonen, H.; Kuffmeier, M.; Evans, D. F.; Peixinho, N.; Hinse, T. C.; Burgdorf, M. J.; Southworth, J.; Tronsgaard, R.; Kerins, E.; Andersen, M. I.; Rahvar, S.; Wang, Y.; Wertz, O.; Novati, S. C.; D'Ago, G.; Scarpetta, G.; Mancini, L.; Abe, F.; Asakura, Y.; Bennett, D. P.; Bhattacharya, A.; Donachie, M.; Evans, P.; Fukui, A.; Hirao, Y.; Itow, Y.; Kawasaki, K.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Miyazaki, S.; Nagakane, M.; Ohnishi, K.; Rattenbury, N.; Saito, T.; Sharan, A.; Shibai, H.; Sullivan, D. J.; Sumi, T.; Suzuki, D.; Tristram, P. J.; Yamada, T.; Yonehara, A.
Digging deeper into the dense Galactic globular cluster Terzan 5 with electron-multiplying CCDs Variable star detection and new discoveries
(2024) Jaimes, R. Figuera; Catelan, M.; Horne, K.; Skottfelt, J.; Snodgrass, C.; Dominik, M.; Jorgensen, U. G.; Southworth, J.; Hundertmark, M.; Longa-Pena, P.; Sajadian, S.; Tregolan-Reed, J.; Hinse, T. C.; Andersen, M. I.; Bonavita, M.; Bozza, V.; Burgdorf, M. J.; Haikala, L.; Khalouei, E.; Korhonen, H.; Peixinho, N.; Rabus, M.; Rahvar, S.
Context. High frame-rate imaging was employed to mitigate the effects of atmospheric turbulence (seeing) in observations of globular cluster Terzan 5.
Faint-source-star planetary microlensing: the discovery of the cold gas-giant planet OGLE-2014-BLG-0676Lb
(2017) Rabus, Markus; Rattenbury, N. J.; Bennett, D. P.; Sumi, T.; Koshimoto, N.; Udalski, A.; Shvartzvald, Y.; Maoz, D.; Jorgensen, U. G.; Street, R. A.; Tsapras, Y.; Abe, F.; Asakura, Y.; Barry, R.; Bhattacharya, A.; Suzuki, D.
Gaia21blx: Complete resolution of a binary microlensing event in the Galactic disk
(2024) Rota, P.; Bozza, V.; Hundertmark, M.; Bachelet, E.; Street, R.; Tsapras, Y.; Cassan, A.; Dominik, M.; Jaimes, R. Figuera; Rybicki, K. A.; Wambsganss, J.; Wyrzykowski, L.; Zielinski, P.; Bonavita, M.; Hinse, T. C.; Jorgensen, U. G.; Khalouei, E.; Korhonen, H.; Longa-Pena, P.; Peixinho, N.; Rahvar, S.; Sajadian, S.; Skottfelt, J.; Snodgrass, C.; Tregolan-Reed, J.
Context. Gravitational microlensing is a method that is used to discover planet-hosting systems at distances of several kiloparsec in the Galactic disk and bulge. We present the analysis of a microlensing event reported by the Gaia photometric alert team that might have a bright lens. Aims. In order to infer the mass and distance to the lensing system, the parallax measurement at the position of Gaia21blx was used. In this particular case, the source and the lens have comparable magnitudes and we cannot attribute the parallax measured by Gaia to the lens or source alone. Methods. Since the blending flux is important, we assumed that the Gaia parallax is the flux-weighted average of the parallaxes of the lens and source. Combining this assumption with the information from the microlensing models and the finite source effects we were able to resolve all degeneracies and thus obtained the mass, distance, luminosities and projected kinematics of the binary lens and the source. Results. According to the best model, the lens is a binary system at 2.18 +/- 0.07 kpc from Earth. It is composed of a G star with 0.95 +/- 0.17 M-circle dot and a K star with 0.53 +/- 0.07 M-circle dot. The source is likely to be an F subgiant star at 2.38 +/- 1.71 kpc with a mass of 1.10 +/- 0.18 M-circle dot. Both lenses and the source follow the kinematics of the thin-disk population. We also discuss alternative models, that are disfavored by the data or by prior expectations, however.
Orbital alignment and star-spot properties in the WASP-52 planetary system
(OXFORD UNIV PRESS, 2017) Mancini, L.; Southworth, J.; Raia, G.; Tregloan Reed, J.; Molliere, P.; Bozza, V.; Bretton, M.; Bruni, I.; Ciceri, S.; D'Ago, G.; Dominik, M.; Hinse, T. C.; Hundertmark, M.; Jorgensen, U. G.; Korhonen, H.; Rabus, M.; Rahvar, S.; Starkey, D.; Novati, S. Calchi; Jaimes, R. Figuera; Henning, Th.; Juncher, D.; Haugbolle, T.; Kains, N.; Popovas, A.; Schmidt, R. W.; Skottfelt, J.; Snodgrass, C.; Surdej, J.; Wertz, O.
We report 13 high-precision light curves of eight transits of the exoplanet WASP-52 b, obtained by using four medium-class telescopes, through different filters, and adopting the defocussing technique. One transit was recorded simultaneously from two different observatories and another one from the same site but with two different instruments, including a multiband camera. Anomalies were clearly detected in five light curves and modelled as star-spots occulted by the planet during the transit events. We fitted the clean light curves with the JKTEBOP code, and those with the anomalies with the PRISM + GEMC codes in order to simultaneously model the photometric parameters of the transits and the position, size and contrast of each star-spot. We used these new light curves and some from the literature to revise the physical properties of the WASP-52 system. Star-spots with similar characteristics were detected in four transits over a period of 43 d. In the hypothesis that we are dealing with the same star-spot, periodically occulted by the transiting planet, we estimated the projected orbital obliquity of WASP-52 b to be. = 3 degrees.8 +/- 8 degrees.4. We also determined the true orbital obliquity, psi = 20 degrees +/- 50 degrees, which is, although very uncertain, the first measurement of. purely from star-spot crossings. We finally assembled an optical transmission spectrum of the planet and searched for variations of its radius as a function of wavelength. Our analysis suggests a flat transmission spectrum within the experimental uncertainties.
PATHWAY TO THE GALACTIC DISTRIBUTION OF PLANETS: COMBINED SPITZER AND GROUND-BASED MICROLENS PARALLAX MEASUREMENTS OF 21 SINGLE-LENS EVENTS
(2015) Novati, S. Calchi; Gould, A.; Udalski, A.; Menzies, J. W.; Bond, I. A.; Shvartzvald, Y.; Street, R. A.; Hundertmark, M.; Beichman, C. A.; Yee, J. C.; Carey, S.; Poleski, R.; Skowron, J.; Kozlowski, S.; Mroz, P.; Pietrukowicz, P.; Pietrzynski, G.; Szymanski, M. K.; Soszynski, I.; Ulaczyk, K.; Wyrzykowski, L.; Albrow, M.; Beaulieu, J. P.; Caldwell, J. A. R.; Cassan, A.; Coutures, C.; Danielski, C.; Prester, D. Dominis; Donatowicz, J.; Loncaric, K.; McDougall, A.; Morales, J. C.; Ranc, C.; Zhu, W.; Abe, F.; Barry, R. K.; Bennett, D. P.; Bhattacharya, A.; Fukunaga, D.; Inayama, K.; Koshimoto, N.; Namba, S.; Sumi, T.; Suzuki, D.; Tristram, P. J.; Wakiyama, Y.; Yonehara, A.; Maoz, D.; Kaspi, S.; Friedmann, M.; Bachelet, E.; Jaimes, R. Figuera; Bramich, D. M.; Tsapras, Y.; Horne, K.; Snodgrass, C.; Wambsganss, J.; Steele, I. A.; Kains, N.; Bozza, V.; Dominik, M.; Jorgensen, U. G.; Alsubai, K. A.; Ciceri, S.; D'Ago, G.; Haugbolle, T.; Hessman, F. V.; Hinse, T. C.; Juncher, D.; Korhonen, H.; Mancini, L.; Popovas, A.; Rabus, M.; Rahvar, S.; Scarpetta, G.; Schmidt, R. W.; Skottfelt, J.; Southworth, J.; Starkey, D.; Surdej, J.; Wertz, O.; Zarucki, M.; Gaudi, B. S.; Pogge, R. W.; De Poy, D. L.
We present microlens parallax measurements for 21 (apparently) isolated lenses observed toward the Galactic bulge that were imaged simultaneously from Earth and Spitzer, which was similar to 1 AU west of Earth in projection. We combine these measurements with a kinematic model of the Galaxy to derive distance estimates for each lens, with error bars that are small compared to the Sun's galactocentric distance. The ensemble therefore yields a well-defined cumulative distribution of lens distances. In principle, it is possible to compare this distribution against a set of planets detected in the same experiment in order to measure the Galactic distribution of planets. Since these Spitzer observations yielded only one planet, this is not yet possible in practice. However, it will become possible as larger samples are accumulated.
Physical properties and transmission spectrum of the WASP-74 planetary system from multiband photometry
(2019) Mancini, L.; Southworth, J.; Molliere, P.; Tregloan-Reed, J.; Juvan, I. G.; Chen, G.; Sarkis, P.; Bruni, I.; D’Ago, Giuseppe; Rabus, Markus; Ciceri, S.; Andersen, M. I.; Bozza, V.; Bramich, D. M.; Burgdorf, M.; Dominik, M.; Evans, D. F.; Jaimes, R. F.; Fossati, L.; Henning, T.; Hinse, T. C.; Hundertmark, M.; Jorgensen, U. G.; Kerins, E.; Korhonen, H.; Kuffmeier, M.; Longa, P.; Peixinho, N.; Popovas, A.; Rahvar, S.; Skottfelt, J.; Snodgrass, C.; Tronsgaard, R.; Wang, Y.; Wertz, O.
Precision measurement of a brown dwarf mass in a binary system in the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035
(2022) Herald, A.; Udalski, A.; Bozza, V.; Rota, P.; Bond, I. A.; Yee, J. C.; Sajadian, S.; Mroz, P.; Poleski, R.; Skowron, J.; Szymanski, M. K.; Soszynski, I.; Pietrukowicz, P.; Kozlowski, S.; Ulaczyk, K.; Rybicki, K. A.; Iwanek, P.; Wrona, M.; Gromadzki, M.; Abe, F.; Barry, R.; Bennett, D. P.; Bhattacharya, A.; Fukui, A.; Fujii, H.; Hirao, Y.; Itow, Y.; Kirikawa, R.; Kondo, I.; Koshimoto, N.; Matsubara, Y.; Matsumoto, S.; Miyazaki, S.; Muraki, Y.; Olmschenk, G.; Ranc, C.; Okamura, A.; Rattenbury, N. J.; Satoh, Y.; Sumi, T.; Suzuki, D.; Silva, S. Ishitani; Toda, T.; Tristram, P. J.; Vandorou, A.; Yama, H.; Beichman, C. A.; Bryden, G.; Novati, S. Calchi; Carey, S.; Gaudi, B. S.; Gould, A.; Henderson, C. B.; Johnson, S.; Shvartzvald, Y.; Zhu, W.; Dominik, M.; Hundertmark, M.; Jorgensen, U. G.; Longa-Pena, P.; Skottfelt, J.; Tregloan-Reed, J.; Bach-Moller, N.; Burgdorf, M.; D'Ago, G.; Haikala, L.; Hitchcock, J.; Khalouei, E.; Peixinho, N.; Rahvar, S.; Snodgrass, C.; Southworth, J.; Spyratos, P.; Zang, W.; Yang, H.; Mao, S.; Bachelet, E.; Maoz, D.; Street, R. A.; Tsapras, Y.; Christie, G. W.; Cooper, T.; de Almeida, L.; do Nascimento, J. -D., Jr.; Green, J.; Han, C.; Hennerley, S.; Marmont, A.; McCormick, J.; Monard, L. A. G.; Natusch, T.; Pogge, R.
Context. Brown dwarfs are transition objects between stars and planets that are still poorly understood, for which several competing mechanisms have been proposed to describe their formation. Mass measurements are generally difficult to carry out for isolated objects as well as for brown dwarfs orbiting low-mass stars, which are often too faint for a spectroscopic follow-up.
Refined physical parameters for Chariklo's body and rings from stellar occultations observed between 2013 and 2020
(2021) Morgado, B. E.; Sicardy, B.; Braga-Ribas, F.; Desmars, J.; Gomes-Junior, A. R.; Berard, 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.; Fernandez-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.; Jorgensen, 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.
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.
Rotation periods and astrometric motions of the Luhman 16AB brown dwarfs by high-resolution lucky-imaging monitoring
(2015) Mancini, L.; Giacobbe, P.; Littlefair, S. P.; Southworth, J.; Bozza, V.; Damasso, M.; Dominik, M.; Hundertmark, M.; Jorgensen, U. G.; Rabus, Markus
Star-spot activity, orbital obliquity, transmission spectrum, physical properties, and transit time variations of the HATS-2 planetary system
(2024) Biagiotti, F.; Mancini, L.; Southworth, J.; Tregloan-Reed, J.; Naponiello, L.; Jorgensen, U. G.; Bach-Moller, N.; Basilicata, M.; Bonavita, M.; Bozza, V.; Burgdorf, M. J.; Dominik, M.; Jaimes, R. Figuera; Henning, Th.; Hinse, T. C.; Hundertmark, M.; Khalouei, E.; Longa-Pena, P.; Peixinho, N.; Rabus, M.; Rahvar, S.; Sajadian, S.; Skottfelt, J.; Snodgrass, C.; Jongen, Y.; Vignes, J. -p
Aims. Our aim in this paper is to refine the orbital and physical parameters of the HATS-2 planetary system and study transit timing variations and atmospheric composition thanks to transit observations that span more than 10 yr and that were collected using different instruments and pass-band filters. We also investigate the orbital alignment of the system by studying the anomalies in the transit light curves induced by starspots on the photosphere of the parent star. Methods. We analysed new transit events from both ground-based telescopes and NASA's TESS mission. Anomalies were detected in most of the light curves and modelled as starspots occulted by the planet during transit events. We fitted the clean and symmetric light curves with the JKTEBOP code and those affected by anomalies with the PRISM+GEMC codes to simultaneously model the photometric parameters of the transits and the position, size, and contrast of each starspot. Results. We found consistency between the values we found for the physical and orbital parameters and those from the discovery paper and ATLAS9 stellar atmospherical models. We identified different sets of consecutive starspot-crossing events that temporally occurred in less than five days. Under the hypothesis that we are dealing with the same starspots, occulted twice by the planet during two consecutive transits, we estimated the rotational period of the parent star and, in turn the projected and the true orbital obliquity of the planet. We find that the system is well aligned. We identified the possible presence of transit timing variations in the system, which can be caused by tidal orbital decay, and we derived a low-resolution transmission spectrum.
THE FIRST SIMULTANEOUS MICROLENSING OBSERVATIONS BY TWO SPACE TELESCOPES: SPITZER AND SWIFT REVEAL A BROWN DWARF IN EVENT OGLE-2015-BLG-1319
(2016) Shvartzvald, Y.; Li, Z.; Udalski, A.; Gould, A.; Sumi, T.; Street, R. A.; Novati, S. Calchi; Hundertmark, M.; Bozza, V.; Beichman, C.; Bryden, G.; Carey, S.; Drummond, J.; Fausnaugh, M.; Gaudi, B. S.; Henderson, C. B.; Tan, T. G.; Wibking, B.; Pogge, R. W.; Yee, J. C.; Zhu, W.; Tsapras, Y.; Bachelet, E.; Dominik, M.; Bramich, D. M.; Cassan, A.; Jaimes, R. Figuera; Horne, K.; Ranc, C.; Schmidt, R.; Snodgrass, C.; Wambsganss, J.; Steele, I. A.; Menzies, J.; Mao, S.; Poleski, R.; Pawlak, M.; Szymanski, M. K.; Skowron, J.; Mroz, P.; Kozlowski, S.; Wyrzykowski, L.; Pietrukowicz, P.; Soszynski, I.; Ulaczyk, K.; Abe, F.; Asakura, Y.; Barry, R. K.; Bennett, D. P.; Bhattacharya, A.; Bond, I. A.; Freeman, M.; Hirao, Y.; Itow, Y.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Fukui, A.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Nishioka, T.; Ohnishi, K.; Oyokawa, H.; Rattenbury, N. J.; Saito, To.; Sharan, A.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; Yonehara, A.; Jorgensen, U. G.; Burgdorf, M. J.; Ciceri, S.; D'Ago, G.; Evans, D. F.; Hinse, T. C.; Kains, N.; Kerins, E.; Korhonen, H.; Mancini, L.; Popovas, A.; Rabus, M.; Rahvar, S.; Scarpetta, G.; Skottfelt, J.; Southworth, J.; Peixinho, N.; Verma, P.; Sbarufatti, B.; Kennea, J. A.; Gehrels, N.
Simultaneous observations of microlensing events from multiple locations allow for the breaking of degeneracies between the physical properties of the lensing system, specifically by exploring different regions of the lens plane and by directly measuring the "microlens parallax." We report the discovery of a 30-65M(J) brown dwarf orbiting a K dwarf in the microlensing event OGLE-2015-BLG-1319. The system is located at a distance of similar to 5 kpc toward the Galactic Bulge. The event was observed by several ground-based groups as well as by Spitzer and Swift, allowing a measurement of the physical properties. However, the event is still subject to an eight-fold degeneracy, in particular the well-known close-wide degeneracy, and thus the projected separation between the two lens components is either similar to 0.25 au or similar to 45 au. This is the first microlensing event observed by Swift, with the UVOT camera. We study the region of microlensing parameter space to which Swift is sensitive, finding that though Swift could not measure the microlens parallax with respect to ground-based observations for this event, it can be important for other events. Specifically, it is important for detecting nearby brown dwarfs and free-floating planets in high magnification events.
THE SPITZER MICROLENSING PROGRAM AS A PROBE FOR GLOBULAR CLUSTER PLANETS: ANALYSIS OF OGLE-2015-BLG-0448
(2016) Poleski, Radoslaw; Zhu, Wei; Christie, Grant W.; Udalski, Andrzej; Gould, Andrew; Bachelet, Etienne; Skottfelt, Jesper; Novati, Sebastiano Calchi; Szymanski, M. K.; Soszynski, I.; Pietrzynski, G.; Wyrzykowski, L.; Ulaczyk, K.; Pietrukowicz, P.; Kozlowski, Szymon; Skowron, J.; Mroz, P.; Pawlak, M.; Beichman, C.; Bryden, G.; Carey, S.; Fausnaugh, M.; Gaudi, B. S.; Henderson, C. B.; Pogge, R. W.; Shvartzvald, Y.; Wibking, B.; Yee, J. C.; Beatty, T. G.; Eastman, J. D.; Drummond, J.; Friedmann, M.; Henderson, M.; Johnson, J. A.; Kaspi, S.; Maoz, D.; McCormick, J.; McCrady, N.; Natusch, T.; Ngan, H.; Porritt, I.; Relles, H. M.; Sliski, D. H.; Tan, T. G.; Wittenmyer, R. A.; Wright, J. T.; Street, R. A.; Tsapras, Y.; Bramich, D. M.; Horne, K.; Snodgrass, C.; Steele, I. A.; Menzies, J.; Jaimes, R. Figuera; Wambsganss, J.; Schmidt, R.; Cassan, A.; Ranc, C.; Mao, S.; Bozza, V.; Dominik, M.; Hundertmark, M. P. G.; Jorgensen, U. G.; Andersen, M. I.; Burgdorf, M. J.; Ciceri, S.; D'Ago, G.; Evans, D. F.; Gu, S. H.; Hinse, T. C.; Kains, N.; Kerins, E.; Korhonen, H.; Kuffmeier, M.; Mancini, L.; Popovas, A.; Rabus, M.; Rahvar, S.; Rasmussen, R. T.; Scarpetta, G.; Southworth, J.; Surdej, J.; Unda-Sanzana, E.; Verma, P.; von Essen, C.; Wang, Y. B.; Wertz, O.
The microlensing event OGLE-2015-BLG-0448 was observed by Spitzer and lay within the tidal radius of the globular cluster NGC 6558. The event had moderate magnification and was intensively observed, hence it had the potential to probe the distribution of planets in globular clusters. We measure the proper motion of NGC 6558 (mu(cl) (N, E) = (+0.36 +/- 0.10, +1.42 +/- 0.10) mas yr(-1)) as well as the source and show that the lens is not a cluster member. Even though this particular event does not probe the distribution of planets in globular clusters, other potential cluster lens events can be verified using our methodology. Additionally, we find that microlens parallax measured using Optical Gravitational Lens Experiment (OGLE) photometry is consistent with the value found based on the light curve displacement between the Earth and Spitzer.
Transit timing variations in the WASP-4 planetary system
(2019) Southworth, J.; Dominik, M.; Jorgensen, U. G.; Andersen, M. I.; Bozza, V.; Burgdorf, M. J.; D'Ago, Giuseppe; Dib, S.; Jaimes, R. F.; Fujii, Y. I.; Gill, S.; Haikala, L. K.; Hinse, T. C.; Hundertmark, M.; Khalouei, E.; Korhonen, H.; Longa Pena, P.; Mancini, L.; Peixinho, N.; Rabus, Markus; Rahvar, S.; Sajadian, S.; Skottfelt, J.; Snodgrass, C.; Spyratos, P.; Tregloan Reed, J.; Unda Sanzana, E.; Von Essen, C.

Browsing by Author "Jorgensen, U. G."

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