Browsing by Author "Bozza, V."

Now showing 1 - 20 of 21
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    A super-jupiter orbiting a late-type star : a refined analysis of microlensing event OGLE-2012-BLG-0406
    (2014) Tsapras, Y.; Choi, J.-Y; Street, R.; Han, C.; Bozza, V.; Gould, A.; Dominik, M.; Beaulieu, J. P.; Udalski, A.; Rabus, Markus
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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.
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    EMCCD photometry reveals two new variable stars in the crowded central region of the globular cluster NGC 6981 (Research Note)
    (2013) Skottfelt, J.; Rabus, Markus; Bramich, D.M.; Figuera Jaimes, R.; Jørgensen, U.G.; Kains, N.; Harpsøe, K.B.W.; Liebig, C.; Penny, M.T.; Alsubai, K.A.; Andersen, J.M.; Bozza, V.; Browne, P.; Calchi Novati, S.; Damerdji, Y.; Diehl, C.; Dominik, M.; Elyiv, A.; Giannini, E.; Hessman, F.; Hinse, T.C.; Hundertmark, M.; Juncher, D.; Kerins, E.; Korhonen, H.; Mancini, L.; Martin, R.; Rahvar, S.; Scarpetta, G.; Southworth, J.; Snodgrass, C.; Street, R.A.; Surdej, J.; Tregloan-Reed, J.; Vilela, C.; Williams, A.
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    Erratum : A. detailed census of variable stars in the globular cluster NGC. 6333 (M9) from CCD. differential photometry
    (2016) Ferro, A.; Bramich, D.; Jaimes, R.; Giridhar, S.; Kains, N.; Kuppuswamy, K.; Jorgensen, U.; Alsubai, K.; Andersen, J.; Rabus, Markus; Bozza, V.; Novati, S.; Damerdji, Y.; Diehl, C.; Dreizler, S.; Elyiv, A.
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    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.
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    High-resolution Imaging of Transiting Extrasolar Planetary systems (HITEP) I. Lucky imaging observations of 101 systems in the southern hemisphere
    (2016) Evans, D.; Southworth, J.; Maxted, P.; Skottfelt, J.; Hundertmark, M.; Jorgensen, U.; Dominik, M.; Alsubai, K.; Andersen, M.; Rabus, Markus; Burgdorf, M.; Ciceri, S.; Jaimes, R.; Gu, S.; Haugbolle, T.; Bozza, V.
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    High-resolution imaging of transiting extrasolar planetary systems (HITEP) II. Lucky imaging results from 2015 and 2016
    (2018) Evans, D. F.; Southworth, J.; Smalley, B.; Jørgensen, U.G.; Dominik, M.; Andersen, M.I.; Bozza, V.; Bramich, D.M.; Burgdorf, M.J.; Rabus, Markus
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    Many new variable stars discovered in the core of the globular cluster NGC. 6715 (M54) with EMCCD. observations
    (2016) Starkey, D.; Street, R.; Surdej, J.; Tronsgaard, R.; Unda-Sanzana, E.; Von Essen, C.; Wang, X.; Wertz, O.; Figuera Jaimes, R.; Rabus, Markus; Bramich, D.; Kains, N.; Skottfelt, J.; Jorgensen, U.; Horne, K.; Dominik, M.; Alsubai, K.; Bozza, V.; Burgdorf, M.; Calchi Novati, S.; Ciceri, S..
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    MASS. MEASUREMENTS. OF. ISOLATED. OBJECTS. FROM. SPACE-BASED. MICROLENSING
    (2016) Zhu, W.; Novati, S.; Gould, A.; Udalski, A.; Han, C.; Shvartzvald, Y.; Ranc, C.; Jorgensen, U.; Poleski, R.; Rabus, Markus; Bozza, V.; Beichman, C.; Bryden, G.; Carey, S.; Gaudi, B.; Henderson, C.
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    OGLE-2017-BLG-0329L : a microlensing binary characterized with dramatically enhanced precision using data from space-based observations
    (2018) Han, C.; Calchi Novati, S.; Udalski, A.; Lee, C.U.; Gould, A.; Bozza, V.; Mróz, P.; Pietrukowicz, Pawel; Skowron, J.; Rabus, Markus
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    OGLE-2018-BLG-0022 : A Nearby M-dwarf Binary
    (2019) Street, R.A.; Bachelet, E.; Tsapras, Y.; Hundertmark, M.P.G.; Bozza, V.; Dominik, M.; Bramich, D.M.; Cassan, A.; Horne, K.; Rabus, Markus; Mao, S.; Saha, A.; Wambsganss, J.; Zang, WC; Jorgensen, UG
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    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.
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    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.
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    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.
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    ROME/REA: Three-year, Tri-color Timeseries Photometry of the Galactic Bulge
    (2024) Street, R. A.; Bachelet, E.; Tsapras, Y.; Hundertmark, M. P. G.; Bozza, V.; Bramich, D. M.; Cassan, A.; Dominik, M.; Figuera Jaimes, R.; Horne, K.; Mao, S.; Saha, A.; Wambsganss, J.; Zang, Weicheng
    The Robotic Observations of Microlensing Events/Reactive Event Assessment Survey was a Key Project at Las Cumbres Observatory (hereafter LCO) which continuously monitored 20 selected fields (3.76 sq.deg) in the Galactic Bulge throughout their seasonal visibility window over a three-year period, between 2017 March and 2020 March. Observations were made in three optical passbands (SDSS-g ', -r ', -i '), and LCO's multi-site telescope network enabled the survey to achieve a typical cadence of similar to 10 hr in i ' and similar to 15 hr in g ' and r ' . In addition, intervals of higher cadence (<1 hr) data were obtained during monitoring of key microlensing events within the fields. This paper describes the Difference Image Analysis data reduction pipeline developed to process these data, and the process for combining the photometry from LCO's three observing sites in the Southern Hemisphere. The full timeseries photometry for all similar to 8 million stars, down to a limiting magnitude of i similar to 18 mag is provided in the data release accompanying this paper, and samples of the data are presented for exemplar microlensing events, illustrating how the tri-band data are used to derive constraints on the microlensing source star parameters, a necessary step in determining the physical properties of the lensing object. The timeseries data also enables a wealth of additional science, for example in characterizing long-timescale stellar variability, and a few examples of the data for known variables are presented.
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    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
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    SPITZER. OBSERVATIONS. OF. OGLE-2015-BLG-1212 REVEAL. A. NEW. PATH. TOWARD. BREAKING. STRONG. MICROLENS. DEGENERACIES
    (2016) Bozza, V.; Shvartzvald, Y.; Udalski, A.; Novati, S. Calchi; Bond, I. A.; Han, C.; Hundertmark, M.; Poleski, R.; Pawlak, M.; Rabus, Markus
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    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.
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    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.