0000000000430039
AUTHOR
L. Mancini
Flux and color variations of the quadruply imaged quasar HE 0435-1223
aims: We present VRi photometric observations of the quadruply imaged quasar HE 0435-1223, carried out with the Danish 1.54m telescope at the La Silla Observatory. Our aim was to monitor and study the magnitudes and colors of each lensed component as a function of time. methods: We monitored the object during two seasons (2008 and 2009) in the VRi spectral bands, and reduced the data with two independent techniques: difference imaging and PSF (Point Spread Function) fitting.results: Between these two seasons, our results show an evident decrease in flux by ~0.2-0.4 magnitudes of the four lensed components in the three filters. We also found a significant increase (~0.05-0.015) in their V-R …
Pruritus characteristics in a large Italian cohort of psoriatic patients
Background: Psoriasis (Ps) is a chronic systemic autoimmune disease associated with pruritus in 64–98% of patients. However, few modestly sized studies assess factors associated with psoriatic pruritus. Objective: To investigate factors associated with Ps pruritus intensity. Methods: Psoriasis patients 18 years or older seen in one of 155 centres in Italy between September 2005 and 2009 were identified from the Italian PsoCare registry. Patients without cutaneous psoriasis and those with missed information on pruritus were excluded. Results: We identified 10 802 patients, with a mean age 48.8 ± 14.3 years. Mild itch was present in 33.2% of patients, moderate in 34.4%, severe in 18.7% and ve…
Efficacy of switching between tumor necrosis factor-alfa inhibitors in psoriasis: results from the Italian Psocare registry
Background: Some studies have shown that switching patients from one tumor necrosis factor (TNF)-alfa inhibitor to another may be beneficial when they have an inadequate response or an adverse event. Objective: We sought to assess the variables predicting the efficacy of the second TNF-alfa inhibitor in patients discontinuing the first TNF-alfa inhibitor. Methods: Data from all 5423 consecutive patients starting TNF-alfa inhibitor therapy for psoriasis between September 2005 and September 2010 who were included in the Italian Psocare registry were analyzed. Results: In 105 patients who switched to a second TNF-alfa inhibitor who had complete follow-up data, 75% improvement in the Psoriasis …
A giant planet beyond the snow line in microlensing event OGLE-2011-BLG-0251
We present the analysis of the gravitational microlensing event OGLE-2011-BLG-0251. This anomalous event was observed by several survey and follow-up collaborations conducting microlensing observations towards the Galactic Bulge. Based on detailed modelling of the observed light curve, we find that the lens is composed of two masses with a mass ratio q=1.9 x 10^-3. Thanks to our detection of higher-order effects on the light curve due to the Earth's orbital motion and the finite size of source, we are able to measure the mass and distance to the lens unambiguously. We find that the lens is made up of a planet of mass 0.53 +- 0.21,M_Jup orbiting an M dwarf host star with a mass of 0.26 +- 0.…
Inferring statistics of planet populations by means of automated microlensing searches
(abridged) The study of other worlds is key to understanding our own, and not only provides clues to the origin of our civilization, but also looks into its future. Rather than in identifying nearby systems and learning about their individual properties, the main value of the technique of gravitational microlensing is in obtaining the statistics of planetary populations within the Milky Way and beyond. Only the complementarity of different techniques currently employed promises to yield a complete picture of planet formation that has sufficient predictive power to let us understand how habitable worlds like ours evolve, and how abundant such systems are in the Universe. A cooperative three-…
Characterizing Lenses and Lensed Stars of High-magnification Single-lens Gravitational Microlensing Events with Lenses Passing over Source Stars
We present the analysis of the light curves of 9 high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-2011-BLG-274, OGLE-2011-BLG-0990/MOA-2011-BLG-300, and OGLE-2011-BLG-1101/MOA-2011-BLG-325. For all events, we measure the linear limb-darkening coefficients of the surface brightness profile of source stars by measuring the deviation of the light curves near the peak affected by the finite-source effect. For 7 events, we measure the Einstein radii and the lens-source relative proper motions. Among the…
KELT-9b radial velocity curve
In the framework of the GAPS project, we observed the planet-hosting star KELT-9 (A-type star, vsini~110km/s) with the HARPS-N spectrograph at the Telescopio Nazionale Galileo. In this work we analyse the spectra and the extracted radial velocities, to constrain the physical parameters of the system and to detect the planetary atmosphere of KELT-9b. We extracted from the high-resolution optical spectra the mean stellar line profiles with an analysis based on the Least Square Deconvolution technique. Then, we computed the stellar radial velocities with a method optimized for fast rotators, by fitting the mean stellar line profile with a purely rotational profile instead of using a Gaussian f…
Microlensing Discovery of a Population of Very Tight, Very Low Mass Binary Brown Dwarfs
Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs (BDs) are poorly understood. The multiplicity properties and minimum mass of the BD mass function provide critical empirical diagnostics of these mechanisms. We present the discovery via gravitational microlensing of two very low mass, very tight binary systems. These binaries have directly and precisely measured total system masses of 0.025 M [SUB]⊙[/SUB] and 0.034 M [SUB]⊙[/SUB], and projected separations of 0.31 AU and 0.19 AU, making them the lowest-mass and tightest field BD binaries known. The discovery of a population of such binaries indicates that BD binaries can …