Results for "G. Lanza"

total 108674took 0.14s
Chaotic Scattering in Heavy--Ion ReactionsSep 03 1993We discuss the relevance of chaotic scattering in heavy--ion reactions at energies around the Coulomb barrier. A model in two and three dimensions which takes into account rotational degrees of freedom is discussed both classically and quantum-mechanically. ... More
The DMTPC projectMar 23 2009The DMTPC detector is a low-pressure CF4 TPC with optical readout for directional detection of Dark Matter. The combination of the energy and directional tracking information allows for an efficient suppression of all backgrounds. The choice of gas (CF4) ... More
Event generator to construct cross sections for the multiphonon excitation of a set of collective vibrational modesMar 09 2010The construction of differential cross sections as a function of excitation energy for systems with a collection of low- and high-lying intrinsic vibrational modes has been attempted in the past. A prescription is proposed that simplifies the implementation ... More
Effect of large neutron excess on the dipole response in the region of the Giant Dipole ResonanceJul 17 1997The evolution of the Dipole Response in nuclei with strong neutron excess is studied in the Hartree-Fock plus Random Phase Approximation with Skyrme forces. We find that the neutron excess increases the fragmentation of the isovector Giant Dipole Resonance, ... More
Population of dipole states via isoscalar probes: the splitting of pygmy dipole resonance in $^{124}$Sn}Mar 29 2014Inelastic $\alpha$-scattering excitation cross sections are calculated for electric dipole excitations in $^{124}$Sn based on the transition densities obtained from the relativistic quasiparticle time-blocking approximation (RQTBA) in the framework of ... More
Multiwavelength flux variations induced by stellar magnetic activity: effects on planetary transitsJan 17 2012Stellar magnetic activity is a source of noise in the study of the transits of extrasolar planets. It induces flux variations which affect significantly the transit depth determination and the derivations of planetary and stellar parameters. Furthermore, ... More
The algebraic molecular model in $^{12}$C and its application to the $α$+$^{12}$C scattering: from densities and transition densities to optical potentials and nuclear formfactorsJan 23 2019The algebraic molecular model is used in $^{12}$C to construct densities and transition densities connecting low-lying states of the rotovibrational spectrum, first and foremost those belonging to the rotational bands based on the ground and the Hoyle ... More
On the Excitation of Double Giant Resonances in Heavy Ion ReactionsApr 28 2003The interplay of nuclear and Coulomb processes in the inelastic excitation of single- and double-phonon giant resonances in heavy ion collisions is studied within a simple reaction model. Predominance of the Coulomb excitation mechanism on the population ... More
Similarity of the variability patterns in the Exosat and Ginga folded light curves of the Seyfert galaxy NGC 6814Jan 08 1993The Seyfert galaxy NGC 6814 is known to show periodic variation of its X-ray luminosity. We found that the sequences of peaks (variability patterns) in the folded X-ray light curves constructed from the {\it Exosat} and {\it Ginga} data are remarkably ... More
Collective transition densities in neutron-rich nucleiOct 25 1996Quadrupole transition densities in neutron-rich nuclei in the vicinity of the neutron drip-line are calculated in the framework of the Random Phase Approximation. The continuum is treated by expansion in oscillator functions. We focus on the states which ... More
Hilbert schemes of points of $\mathcal O_{\mathbb P^1}(-n)$ as quiver varietiesApr 12 2015May 02 2015Relying on a monadic description of the moduli space of framed sheaves on Hirzebruch surfaces, we construct ADHM data for the Hilbert scheme of points of the total space of the line bundle $\mathcal O(-n)$ on $\mathbb P^1$. This ADHM description is then ... More
Reducing activity-induced variations in a radial-velocity time series of the Sun as a starApr 11 2019The radial velocity of the Sun as a star is affected by its surface convection and magnetic activity. The moments of the cross-correlation function between the solar spectrum and a binary line mask contain information about the stellar radial velocity ... More
The HADES RV Programme with HARPS-N at TNG XI. GJ 685 b: a warm super-Earth around an active M dwarfMar 28 2019Small rocky planets seem to be very abundant around low-mass M-type stars. Their actual planetary population is however not yet precisely understood. Currently several surveys aim to expand the statistics with intensive detection campaigns, both photometric ... More
ADHM data for the Hilbert scheme of points of the total space of $\mathcal O_{\mathbb P^1}(-n)$Mar 03 2014Dec 06 2014Relying on a monadic description of the moduli space of framed sheaves on Hirzebruch surfaces, we construct ADHM data for the Hilbert scheme of points of the total space of the line bundle $\mathcal O(-n)$ on $\mathbb P^1$.
Higher Forms and Membranes in 4D SupergravitiesMar 07 2019We review the dynamical generation of coupling constants in 4D supergravity by means of gauge three-form fields. The latter are introduced as components of particular chiral supermultiplets and can be coupled to membranes preserving local supersymmetry. ... More
Evidence for vortex staircases in the whole angular range due to competing correlated pinning mechanismsFeb 22 1999We analyze the angular dependence of the irreversible magnetization of YBa$_2$Cu$_3$O$_7$ crystals with columnar defects inclined from the c-axis. At high fields a sharp maximum centered at the tracks' direction is observed. At low fields we identify ... More
DMTPC: Dark matter detection with directional sensitivityDec 17 2010The Dark Matter Time Projection Chamber (DMTPC) experiment uses CF_4 gas at low pressure (0.1 atm) to search for the directional signature of Galactic WIMP dark matter. We describe the DMTPC apparatus and summarize recent results from a 35.7 g-day exposure ... More
DMTPC: a new apparatus for directional detection of Dark MatterOct 01 2008Directional detection of Dark Matter allows for unambiguous direct detection of WIMPs as well as discrimination between various Dark Matter models in our galaxy. The DMTPC detector is a low-pressure TPC with optical readout designed for directional direct ... More
Background Rejection in the DMTPC Dark Matter Search Using Charge SignalsSep 15 2011The Dark Matter Time Projection Chamber (DMTPC) collaboration is developing low-pressure gas TPC detectors for measuring WIMP-nucleon interactions. Optical readout with CCD cameras allows for the detection for the daily modulation in the direction of ... More
Spot modelling of periodic weak-line T Tauri stars observed by CoRoT in NGC 2264Jun 20 2016The space telescope CoRoT has provided light curves of T Tauri stars belonging to the star-forming region of NGC 2264 with unprecedented continuity and precision in the framework of a coordinated multi-wavelength observational project. We perform spot ... More
The DMTPC detectorNov 18 2008Directional detection of Dark Matter allows for unambiguous direct detection of WIMPs as well as discrimination between various Dark Matter models in our galaxy. The DMTPC detector is a low-pressure TPC with optical readout designed for directional direct ... More
First Dark Matter Search Results from a Surface Run of the 10-L DMTPC Directional Dark Matter DetectorJun 15 2010Dec 09 2010The Dark Matter Time Projection Chamber (DMTPC) is a low pressure (75 Torr CF4) 10 liter detector capable of measuring the vector direction of nuclear recoils with the goal of directional dark matter detection. In this paper we present the first dark ... More
Excitation of multiple giant dipole resonances: from spherical to deformed nucleiOct 20 1999The effect of deformation on the excitation of multiple giant dipole resonances is studied. Analytical expressions are derived in the framework of the interacting boson model for the energies and E1 properties of giant dipole resonances in spherical and ... More
Microscopic calculations of double and triple Giant Resonance excitation in heavy ion collisionsNov 22 2006We perform microscopic calculations of the inelastic cross sections for the double and triple excitation of giant resonances induced by heavy ion probes within a semicalssical coupled channels formalism. The channels are defined as eigenstates of a bosonic ... More
Excitation of the GDR and the Compressional Isoscalar Dipole State by alpha scatteringNov 24 1998The excitation of the isovector giant dipole resonance (GDR) by alpha scattering is investigated as a method of probing the neutron excess in exotic nuclei. DWBA calculations are presented for 28O and 70Ca and the interplay of Coulomb and nuclear excitation ... More
Daily variability of Ceres' Albedo detected by means of radial velocities changes of the reflected sunlightFeb 10 2016Bright features have been recently discovered by Dawn on Ceres, which extend previous photometric and Space Telescope observations. These features should produce distortions of the line profiles of the reflected solar spectrum and therefore an apparent ... More
Coupling of Dipole Mode to gamma-unstable Quadrupole OscillationsJul 24 2000The coupling of the high-lying dipole mode to the low-lying quadrupole modes for the case of deformed gamma-unstable nuclei is studied. Results from the geometrical model are compared to those obtained within the dipole boson model. Consistent results ... More
Anharmonic vibrations in nucleiNov 06 2001In this letter, we show that the non-linearitites of large amplitude motions in atomic nuclei induce giant quadrupole and monopole vibrations. As a consequence, the main source of anharmonicity is the coupling with configurations including one of these ... More
Role of the Low-Lying Isoscalar Dipole Modes in the Polarization PotentialFeb 21 1994An analysis of the real and imaginary part of the polarization potential in terms of the relative contributions of the single collective states for the $ ^{208}Pb + ^{208}Pb $ system has been done. The polarization potential has been calculated within ... More
Excitation of Pygmy Dipole Resonance in neutron-rich nuclei via Coulomb and nuclear fieldsJan 27 2010We study the nature of the low-lying dipole strength in neutron-rich nuclei, often associated to the Pygmy Dipole Resonance. The states are described within the Hartree-Fock plus RPA formalism, using different parametrizations of the Skyrme interaction. ... More
Microscopic description of Coulomb and nuclear excitation of multiphonon states in $^{40}$Ca + $^{40}$Ca collisionsOct 30 2001We calculate the inelastic scattering cross sections to populate one- and two-phonon states in heavy ion collisions with both Coulomb and nuclear excitations. Starting from a microscopic approach based on RPA, we go beyond it in order to treat anharmonicities ... More
Boson expansion methods applied to a two-level model in the study of multiple giant resonancesNov 24 1998We apply boson expansion methods to an extended Lipkin-Meshkov-Glick model including anharmonicities in analogy with previous microscopic calculations. We study the effects of different approximations present in these calculations, among which the truncation ... More
CoRoT and stellar activity: preliminary results from the modelling of CoRoT-Exo-2aSep 01 2008We present a preliminary analysis of the photospheric activity of CoRoT-Exo-2a, a young G7V star accompanied by a transiting hot Jupiter recently discovered by CoRoT. We apply spot modelling techniques developed for the analysis of the Sun as a star and ... More
Role of anharmonicities and non-linearities in heavy ion collisions. A microscopic approachJul 26 1996Using a microscopic approach beyond RPA to treat anharmonicities, we mix two-phonon states among themselves and with one-phonon states. We also introduce non-linear terms in the external field. These non-linear terms and the anharmonicities are not taken ... More
Nuclear excitations as coupled one and two random--phase--approximation modesSep 27 2015We present an extension of the random--phase approximation (RPA) where the RPA phonons are used as building blocks to construct the excited states. In our model, that we call double RPA (DRPA), we include up to two RPA phonons. This is an approximate ... More
Controlled Phase Separation in La_0.5 Ca_0.5 Mn O_3May 15 2000Nov 06 2000A systematic study of phase separation effects in polycrystalline La_0.5 Ca_0.5 Mn O_3 obtained under different thermal treatments is reported. Samples with average grain size ranging from 200 to 1300 nm were studied. Magnetic and electrical measurements ... More
Hot Jupiters and stellar magnetic activityMay 20 2008Recent observations suggest that stellar magnetic activity may be influenced by the presence of a close-by giant planet. Specifically, chromospheric hot spots rotating in phase with the planet orbital motion have been observed during some seasons in a ... More
Low RF power plasma ignition and detection for in-situ cleaning of 1.3 GHz 9-cell cavitiesFeb 08 2019Superconducting Radio Frequency (SRF) cavities performance preservation is crucial, from vertical test to accelerator operation. Field Emission (FE) is still one of the performance limiting factors to overcome and plasma cleaning has been proven successful ... More
Searching for star-planet magnetic interaction in CoRoT observationsSep 23 2011Close-in massive planets interact with their host stars through tidal and magnetic mechanisms. In this paper, we review circumstantial evidence for star-planet interaction as revealed by the photospheric magnetic activity in some of the CoRoT planet-hosting ... More
Angular momentum conservation and torsional oscillations in the Sun and solar-like starsJun 12 2007The solar torsional oscillations, i.e., the perturbations of the angular velocity of rotation associated with the eleven-year activity cycle, are a manifestation of the interaction among the interior magnetic fields, amplified and modulated by the solar ... More
On decoherence in quantum gravityAug 21 2015Feb 26 2017It was previously argued that the phenomenon of quantum gravitational decoherence described by the Wheeler-DeWitt equation is responsible for the emergence of the arrow of time. Here we show that the characteristic spatio-temporal scales of quantum gravitational ... More
Hot Jupiters and the evolution of stellar angular momentumDec 23 2009Giant planets orbiting main-sequence stars closer than 0.1 AU are called hot Jupiters. They interact with their stars affecting their angular momentum. Recent observations provide suggestive evidence of excess angular momentum in stars with hot Jupiters ... More
On decoherence in non-renormalizable field theories and quantum gravityAug 21 2015It was previously argued that the phenomenon of quantum gravitational decoherence described by the Wheeler-DeWitt equation is responsible for the emergence of the arrow of time. Here we show that the characteristic spatio-temporal scales of quantum gravitational ... More
Doppler Images of the RS CVn Binary HR 1099 (V711 Tau) from the MUSICOS 1998 CampaignMar 07 2003We present Doppler Images of the RS CVn binary system HR 1099 (V711 Tau) from spectra taken in two different sites, KPNO and MSO, during the MUSICO S 1998 campaign. Contemporaneous APT photometry is used to constrain the Doppler Images. The resulting ... More
Star-planet interactionsAug 26 2014Stars interact with their planets through gravitation, radiation, and magnetic fields. I shall focus on the interactions between late-type stars with an outer convection zone and close-in planets, i.e., with an orbital semimajor axis smaller than approximately ... More
Current state of the modelling of photospheric activityFeb 10 2012I briefly review the current state of the modelling of photospheric activity based on the high-precision optical light curves obtained with MOST, CoRoT, and Kepler. These models can be used to search for active longitudes where activity is preferentially ... More
Stellar activity, differential rotation, and exoplanetsSep 21 2010The photospheric spot activity of some of the stars with transiting planets discovered by the CoRoT space experiment is reviewed. Their out-of-transit light modulations are fitted by a spot model previously tested with the total solar irradiance variations. ... More
Stellar magnetic cyclesSep 25 2009The solar activity cycle is a manifestation of the hydromagnetic dynamo working inside our star. The detection of activity cycles in solar-like stars and the study of their properties allow us to put the solar dynamo in perspective, investigating how ... More
Stellar coronal magnetic fields and star-planet interactionJun 09 2009Evidence of magnetic interaction between late-type stars and close-in giant planets is provided by the observations of stellar hot spots rotating synchronously with the planets and showing an enhancement of chromospheric and X-ray fluxes. We investigate ... More
Star-planet magnetic interaction and evaporation of planetary atmospheresJul 09 2013Stars interact with their close-in planets through radiation, gravitation, and magnetic fields. We investigate the energy input to a planetary atmosphere by reconnection between stellar and planetary magnetic fields and compare it to the energy input ... More
Modelling the time variation of the surface differential rotation in AB Doradus and LQ HydraeOct 11 2007Sequences of Doppler images of the young, rapidly rotating late-type stars AB Dor and LQ Hya show that their equatorial angular velocity and the amplitude of their surface differential rotation vary versus time. Such variations can be modelled to obtain ... More
On the codimension of Noether-Lefshetz loci for toric threefoldsJul 30 2018In this manuscript we sharpen the lower bound on the codimension of the irreducible components of the Noether-Lefschetz locus of surfaces in projective toric threefolds given in [BG17]. We also provide a simpler proof of Theorem 4.11 in [BG17], which ... More
Stellar activity and rotation of the planet host Kepler-17 from long-term space-borne photometryApr 09 2019The study of young Sun-like stars is of fundamental importance to understand the magnetic activity and rotational evolution of the Sun. Space-borne photometry by the Kepler telescope provides unprecedented datasets to investigate these phenomena in Sun-like ... More
On the correlation between stellar chromospheric flux and the surface gravity of close-in planetsOct 30 2014Nov 10 2014The chromospheric emission of stars with close-in transiting planets has been found to correlate with the surface gravity of their planets. Stars with low-gravity planets have on average a lower chromospheric flux. We propose that this correlation is ... More
Star-planet magnetic interaction and activity in late-type stars with close-in planetsJun 26 2012Late-type stars interact with their close-in planets through their coronal magnetic fields. We introduce a theory for the interaction between the stellar and planetary fields focussing on the processes that release magnetic energy in the stellar coronae. ... More
Integral potential method for a transmission problem with Lipschitz interface in ${\mathbb R}^3$ for the Stokes and Darcy-Forchheimer-Brinkman PDE systemsOct 16 2015Sep 04 2016The purpose of this paper is to obtain existence and uniqueness results in weighted Sobolev spaces for transmission problems for the non-linear Darcy-Forchheimer-Brinkman system and the linear Stokes system in two complementary Lipschitz domains in ${\mathbb ... More
Multiple and changing cycles of active stars II. ResultsApr 10 2009We study the time variations of the cycles of 20 active stars based on decades-long photometric or spectroscopic observations. A method of time-frequency analysis, as discussed in a companion paper, is applied to the data. Fifteen stars definitely show ... More
Determination of rotation periods in solar-like stars with irregular sampling: the Gaia caseFeb 03 2012We present a study on the determination of rotation periods (P) of solar-like stars from the photometric irregular time-sampling of the ESA Gaia mission, currently scheduled for launch in 2013, taking into account its dependence on ecliptic coordinates. ... More
Disentangling planetary and stellar activity features in the CoRoT-2 light curveAug 05 2016[Abridged] Context. Stellar activity is an important source of systematic errors and uncertainties in the characterization of exoplanets. Most of the techniques used to correct for this activity focus on an ad hoc data reduction. Aims. We have developed ... More
Tides and angular momentum redistribution inside low-mass stars hosting planets: a first dynamical modelJun 28 2016We introduce a general mathematical framework to model the internal transport of angular momentum in a star hosting a close-in planetary/stellar companion. By assuming that the tidal and rotational distortions are small and that the deposit/extraction ... More
Measurement of the radial velocity of the Sun as a star by means of a reflecting solar system body. The effect of the body rotationMay 05 2015Minor bodies of the solar system can be used to measure the spectrum of the Sun as a star by observing sunlight reflected by their surfaces. To perform an accurate measurement of the radial velocity of the Sun as a star by this method, it is necessary ... More
Evolution of angular-momentum-losing exoplanetary systems : Revisiting Darwin stabilityNov 14 2014Nov 30 2014We assess the importance of tidal evolution and its interplay with magnetic braking in the population of hot-Jupiter planetary systems. By minimizing the total mechanical energy of a given system under the constraint of stellar angular momentum loss, ... More
Prospecting transit duration variations in extrasolar planetary systemsSep 05 2011Oct 03 2011In transiting planetary systems, the angle between the orbital angular momentum and the stellar spin is usually constrained through the Rossiter-McLaughlin effect observed in radial velocity and can be subject to large uncertainties, especially for hot ... More
Radiation and magnetic field effects on new semiconductor power devices for HL-LHC experimentsOct 07 2013The radiation hardness of commercial Silicon Carbide and Gallium Nitride power MOSFETs is presented in this paper, for Total Ionizing Dose effects and Single Event Effects, under gamma, neutrons, protons and heavy ions. Similar tests are discussed for ... More
Starspots on the fastest rotators in the Beta Pic moving groupJul 28 2011Aug 11 2011Aims: We carried out high-resolution spectroscopy and BV(I)_C photometric monitoring of the two fastest late-type rotators in the nearby Beta Pictoris moving group, HD199143 (F7V) and CD-641208 (K7V). The motivation for this work is to investigate the ... More
Coordinated X-ray and Optical observations of Star-Planet Interaction in HD 17156Sep 02 2015Sep 15 2015The large number of close-in Jupiter-size exoplanets prompts the question whether star-planet interaction (SPI) effects can be detected. We focused our attention on the system HD 17156, having a Jupiter-mass planet in a very eccentric orbit. Here we present ... More
A Background-Free Direction-Sensitive Neutron Detector2 A Background-Free Direction-Sensitive Neutron DetectorJun 22 2009We show data from a new type of detector that can be used to determine neutron flux, energy distribution, and direction of neutron motion for both fast and thermal neutrons. Many neutron detectors are plagued by large backgrounds from x-rays and gamma ... More
Polar branches of stellar activity waves: dynamo models and observationsMay 05 2011[Abridged abstract:] Stellar activity data provide evidence of activity wave branches propagating polewards rather than equatorwards (the solar case). Stellar dynamo theory allows polewards propagating dynamo waves for certain governing parameters. We ... More
Hadron detection with a dual-readout fiber calorimeterMar 27 2017In this paper, we describe measurements of the response functions of a fiber-based dual- readout calorimeter for pions, protons and multiparticle "jets" with energies in the range from 10 to 180 GeV. The calorimeter uses lead as absorber material and ... More
Photospheric activity, rotation, and star-planet interaction of the planet-hosting star CoRoT-6Jul 21 2010Sep 21 2010The CoRoT satellite has recently discovered a hot Jupiter that transits across the disc of a F9V star called CoRoT-6 with a period of 8.886 days. We model the photospheric activity of the star and use the maps of the active regions to study stellar differential ... More
Toward directional detection of Dark Matter with the DM-TPC detectorJun 16 2008Directional detection can provide unambiguous observation of Dark Matter interactions even in presence of insidious backgrounds. The DM-TPC collaboration is developing a detector with the goal of measuring the direction and sense of nuclear recoils produced ... More
Improved measurement of the head-tail effect in nuclear recoilsJan 17 2008We present new results with a prototype detector that is being developed by the DMTPC collaboration for the measurement of the direction tag (head-tail) of dark matter wind. We use neutrons from a Cf-252 source to create low-momentum nuclear recoils in ... More
Transport properties of electrons in CF4May 15 2009Carbon-tetrafluoride (CF4) is used as a counting gas in particle detectors, but some of its properties that are of interest for large time-projection chambers are not well known. We measure the mean energy, which is proportional to the diffusion coefficent, ... More
Charge amplification concepts for direction-sensitive dark matter detectorsApr 30 2008Aug 22 2008Direction measurement of weakly interacting massive particles in time-projection chambers can provide definite evidence of their existence and help to determine their properties. This article demonstrates several concepts for charge amplification in time-projection ... More
A bimodal correlation between host star chromospheric emission and the surface gravity of hot JupitersOct 15 2015The chromospheric activity index logR'HK of stars hosting transiting hot Jupiters appears to be correlated with the planets' surface gravity. One of the possible explanations is based on the presence of condensations of planetary evaporated material located ... More
Starspot activity and rotation of the planet-hosting star Kepler-17Oct 05 2012Context. Kepler-17 is a G2V sun-like star accompanied by a transiting planet with a mass of ~2.5 Jupiter masses and an orbital period of 1.486 d, recently discovered by the Kepler space telescope. This star is highly interesting as a young solar analogue. ... More
Photospheric activity and rotation of the planet-hosting star CoRoT-Exo-4aJan 29 2009The space experiment CoRoT has recently detected a transiting hot Jupiter in orbit around a moderately active F-type main-sequence star (CoRoT-Exo-4a). This planetary system is of particular interest because it has an orbital period of 9.202 days, the ... More
Observation of the 'head-tail' effect in nuclear recoils of low-energy neutronsAug 17 2007Oct 09 2007Directional detection of dark matter can provide unambiguous observation of dark matter interactions even in the presence of background. This article presents an experimental method to measure the direction tag ("head-tail") of the dark matter wind by ... More
LOCNES: Low Cost NIR Extended Solar TelescopeAug 09 2018The search for telluric extrasolar planets with the Radial Velocity (RV) technique is intrinsically limited by the stellar jitter due to the activity of the star, because stellar surface inhomogeneities, including spots, plages and convective granules, ... More
On the runaway instability of relativistic toriDec 18 1997We further investigate the runaway instability of relativistic tori around black holes assuming a power law distribution of the specific angular momentum. We neglect the self-gravity of the torus; thus the gravitational field of the system is determined ... More
Modelling solar-like variability for the detection of Earth-like planetary transits. I. Performance of the three-spot modelling and harmonic function fittingFeb 21 2008We present a comparison of two methods of fitting solar-like variability to increase the efficiency of detection of Earth-like planetary transits across the disk of a Sun-like star. One of them is the harmonic fitting method that coupled with the BLS ... More
Time evolution and rotation of starspots on CoRoT-2 from the modelling of transit photometryFeb 10 2011CoRoT-2, the second planet-hosting star discovered by the CoRoT satellite, is a young and active star. A total of 77 transits were observed for this system over a period of 135 days. Small modulations detected in the optical light curve of the planetary ... More
Anomaly Detection for Network Connection LogsDec 01 2018We leverage a streaming architecture based on ELK, Spark and Hadoop in order to collect, store, and analyse database connection logs in near real-time. The proposed system investigates outliers using unsupervised learning; widely adopted clustering and ... More
Emission Line Profiles from Self-Gravitating Thin DisksSep 14 1994We have constructed general relativistic models of a stationary, axially symmnetric, Keplerian thin disk around a rotating black hole. We computed profiles of a spectral line, emitted in the inner region of the disk. In our models we have taken into account ... More
Comparing the performance of stellar variability filters for the detection of planetary transitsJun 27 2008We have developed a new method to improve the transit detection of Earth-sized planets in front of solar-like stars by fitting stellar microvariability by means of a spot model. A large Monte Carlo numerical experiment has been designed to test the performance ... More
Bonding of Cobalt Atoms, Dimers and Co$_4$ Clusters to CircumcoroneneApr 25 2017We study the interaction of circumcoronene molecule C$_{54}$H$_{18}$ with cobalt in the form of atoms, dimers and clusters of four atoms. We find that the cobalt atom prefers to be on a hollow site in the edge zone. The cobalt dimer is bonded perpendicularly ... More
A Measurement of Photon Production in Electron Avalanches in CF4Mar 14 2008This paper presents a measurement of the ratio of photon to electron production and the scintillation spectrum in a popular gas for time pro jection chambers, carbon tetrafluoride (CF4), over the range of 200 to 800 nm; the ratio is measured to be 0.34+/-0.04. ... More
DMTPC-10L: Direction-Sensitive Dark Matter Detector PrototypeOct 15 2008The known direction of motion of dark matter particles relative to the Earth may be a key for their unambiguous identification even in the presence of backgrounds. We describe a prototype detector that is able to reconstruct direction vectors of weakly ... More
Depletion of chlorine into HCl ice in a protostellar coreNov 24 2014The freezeout of gas-phase species onto cold dust grains can drastically alter the chemistry and the heating-cooling balance of protostellar material. In contrast to well-known species such as carbon monoxide (CO), the freezeout of various carriers of ... More
Photospheric activity, rotation, and radial velocity variations of the planet-hosting star CoRoT-7May 20 2010The CoRoT satellite has recently discovered the transits of a telluric planet across the disc of a late-type magnetically active star dubbed CoRoT-7, while a second planet has been detected after filtering out the radial velocity (hereafter RV) variations ... More
DM-TPC: a new approach to directional detection of Dark MatterMay 16 2008Directional detection can provide unambiguous observation of Dark Matter interactions even in presence of insidious backgrounds. The DM-TPC collaboration is developing a detector with the goal of measuring the direction and sense of nuclear recoils produced ... More
Secular orbital evolution of planetary systems and the dearth of close-in planets around fast rotatorsMay 28 2014Jun 18 2014Recent analyses of Kepler space telescope data reveal that transiting planets with orbital periods shorter than about 2-3 days are generally observed around late-type stars with rotation periods longer than about 5-10 days. We investigate different explanations ... More
Constraining tidal dissipation in F-type main-sequence stars: the case of CoRoT-11Dec 28 2010Feb 18 2011Tidal dissipation in late-type stars is presently poorly understood and the study of planetary systems hosting hot Jupiters can provide new observational constraints to test proposed theories. We focus on systems with F-type main-sequence stars and find ... More
A Big Data Architecture for Log Data Storage and AnalysisDec 01 2018We propose an architecture for analysing database connection logs across different instances of databases within an intranet comprising over 10,000 users and associated devices. Our system uses Flume agents to send notifications to a Hadoop Distributed ... More
Semistable Higgs bundles on Calabi-Yau manifoldsOct 10 2017We provide a partial classification of semistable Higgs bundles over a simply connected Calabi-Yau manifolds. Applications to a conjecture about a special class of semistable Higgs bundles are given. In particular, the conjecture is proved for K3 and ... More
A coordinated optical and X-ray spectroscopic campaign on HD179949: searching for planet-induced chromospheric and coronal activityJan 31 2013HD179949 is an F8V star, orbited by a close-in giant planet with a period of ~3 days. Previous studies suggested that the planet enhances the magnetic activity of the parent star, producing a chromospheric hot spot which rotates in phase with the planet ... More
Gaia Data Release 2: Rotational modulation in late-type dwarfsMay 01 2018Jun 27 2018We present the methods devised to identify the BY Dra variables candidates in Gaia DR2 and infer their variability parameters. BY Dra candidates are pre-selected from their position in the HR diagram, built from Gaia parallaxes, $G$ magnitudes, and $(G_{BP} ... More
Performance of Resistive Plate Chambers installed during the first long shutdown of the CMS experimentMay 22 2016The CMS experiment, located at the CERN Large Hadron Collider, has a redundant muon system composed by three different detector technologies: Cathode Strip Chambers (in the forward regions), Drift Tubes (in the central region) and Resistive Plate Chambers ... More
High rate, fast timing Glass RPC for the high η CMS muon detectorsJun 04 2016Jul 22 2016The HL-LHC phase is designed to increase by an order of magnitude the amount of data to be collected by the LHC experiments. To achieve this goal in a reasonable time scale the instantaneous luminosity would also increase by an order of magnitude up to ... More
Radiation Tests of Real-Sized Prototype RPCs for the Future CMS RPC UpscopeMay 02 2016May 04 2016We report on a systematic study of double-gap and four-gap phenolic resistive plate chambers (RPCs) for future high-{\eta} RPC triggers in the CMS. In the present study, we constructed real-sized double-gap and four-gap RPCs with gap thicknesses of 1.6 ... More