Ir Observations Of An Outburst In Comet Hale-Bopp (C/1995 O1)     

Tozzi  Gian Paolo  Mannucci  Filippo  Stanga  Ruggero 《Earth, Moon, and Planets》1997,78(1-3):279-284

The comet Hale-Bopp (C/1995 O1) has been observed in the infrared (1–2.5 μm) with the Nordic Optical Telescope (NOT) equipped with the Arcetri NICMOS3 camera (ARNICA). Two observational campaigns, each one lasting about one week, were made when the comet heliocentric distance was about 3 AU. The first campaign was at the end of August and the second at the end of September 1996. During both runs two major outbursts were observed, the more intense of them started the day before the beginning of the second run. In the images recorded during the first three nights (24.8–26.8 Sept.) of the second run a dust shell expanding in the northern quadrant with a projected velocity of 0.14–0.28 km/s is clearly evident. The dust production rate increased by at least a factor ≈3 at the time of the outburst. Also evident on the first night is a change in the IR color that is well correlated with the dust shell. This is an indication that the material released by the outburst has a different composition and/or size distribution than that in the “quiescent” dust coma. In this paper we present preliminary results about the evolution and the photometric characteristics of the dust shell. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

A Simulation Method for Semicollisional Plasmas     

Filippo Pantellini  Simone Landi 《Astrophysics and Space Science》2001,277(1-2):149-152

We present a one dimensional kinetic simulation model which can be used to simulate the stationary state of a semicollisional plasma. Results of a simple simulation are presented and compared to Fokker-Planck calculations. The model is particularly well suited for the diluted solar atmosphere. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Atmospheric Background Measurement in the 300–400 nm Band with a Balloon Borne Experiment During a Nocturnal Flight     

Giovanni La Rosa  Gaetano Agnetta  Benedetto Biondo  Osvaldo Catalano  Filippo Celi  Renato Di Raffaele  Salvatore Giarrusso  Angelo Mangano  Francesco Russo  John Linsley  Angelo Lo Bue 《Astrophysics and Space Science》2001,276(1):219-226

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Optical properties of Laue lenses for hard X-rays (>60 keV)     

Alessandro Pisa  Filippo Frontera  Gianluca Loffredo  Damiano Pellicciotta  Natalia Auricchio 《Experimental Astronomy》2005,20(1-3):219-228

We report on preliminary results obtained with a Monte Carlo (MC) code developed to study the optical properties of Laue lenses for astro-physical observations. The MC code is written in the Python programming language and uses open source libraries. Among the physical quantities which can be investigated with the MC code, we paid our attention mainly to the estimation of the effective area, field of view (FOV) and point spread function (PSF) of the lens for observation of sources on-axis and off-axis.  相似文献   

Evolution of Br/Cl ratios in fumarolic salammoniac from Vulcano (Aeolian Islands,Italy)     

Nara Coradossi  Anna Garavelli  Martino Salamida  Filippo Vurro 《Bulletin of Volcanology》1996,58(4):310-316

 Bromine/chlorine ratios in salammoniac samples, collected from 1983 to 1994 at the Fossa crater fumaroles of Vulcano (Aeolian Islands), were determined. The data obtained in this work have been compared to those obtained by Coradossi et al. (1985) in order to carry out a systematic study of the Br/Cl ratio variations since 1977. Br/Cl ratios range from 0.04 to 0.29. The Br/Cl ratio variations observed have been interpreted as the result of different contributions among deep and shallow components feeding the fumarolic fluids of Vulcano. The Br/Cl increases, which occurred from 1977 to 1979, in 1983–1984 and in 1992–1993, have been connected to an increased input of magmatic gases. Received: 10 November 1995 / Accepted: 12 July 1996  相似文献   

Projected seasonal mean summer monsoon over India and adjoining regions for the twenty-first century     

Sushil K. Dash  Saroj K. Mishra  Kanhu C. Pattnayak  Ashu Mamgain  Laura Mariotti  Erika Coppola  Filippo Giorgi  Graziano Giuliani 《Theoretical and Applied Climatology》2015,122(3-4):581-593

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A DUAL mission for nuclear astrophysics     

Peter von Ballmoos  Jose Alvarez  Nicolas Barrière  Steve Boggs  Andrei Bykov  Juan Manuel Del Cura Velayos  Filippo Frontera  Lorraine Hanlon  Margarita Hernanz  Emmanuel Hinglais  Jordi Isern  Pierre Jean  Jürgen Kn?dlseder  Lucien Kuiper  Mark Leising  Beno?t Pirard  Jean-Pierre Prost  Rui M. Curado da Silva  Tadayuki Takahashi  John Tomsick  Roland Walter  Andreas Zoglauer 《Experimental Astronomy》2012,34(2):583-622

DUAL will study the origin and evolution of the elements and explores new frontiers of physics: extreme energies that drive powerful stellar explosions and accelerate particles to macroscopic energies; extreme densities that modify the laws of physics around the most compact objects known; and extreme fields that influence matter in a way that is unknown on Earth. The variability of these extreme objects requires continuous all-sky coverage, while detailed study demands an improvement in sensitivity over previous technologies by at least an order of magnitude. The DUAL payload is composed of an All-Sky Compton Imager (ASCI), and two optical modules, the Laue-Lens Optic (LLO) and the Coded-Mask Optic (CMO). The ASCI serves dual roles simultaneously, both as an optimal focal-plane sensor for deep observations with the optical modules and as a sensitive true all-sky telescope in its own right for all-sky surveys and monitoring. While the optical modules are located on the main satellite, the All-Sky Compton Imager is situated on a deployable structure at a distance of 30?m from the satellite. This configuration not only permits to maintain the less massive payload at the focal distance, it also greatly reduces the spacecraft-induced detector background, and, above all it provides ASCI with a continuous all-sky exposure.  相似文献   

Nano dust impacts on spacecraft and boom antenna charging     

Filippo Pantellini  Soraya Belheouane  Nicole Meyer-Vernet  Arnaud Zaslavsky 《Astrophysics and Space Science》2012,341(2):309-314

High rate sampling detectors measuring the potential difference between the main body and boom antennas of interplanetary spacecraft have been shown to be efficient means to measure the voltage pulses induced by nano dust impacts on the spacecraft body itself (see Meyer-Vernet et al. in Sol. Phys. 256:463, 2009). However, rough estimates of the free charge liberated in post impact expanding plasma cloud indicate that the cloud’s own internal electrostatic field is too weak to account for measured pulses as the ones from the TDS instrument on the STEREO spacecraft frequently exceeding 0.1 V/m. In this paper we argue that the detected pulses are not a direct measure of the potential structure of the plasma cloud, but are rather the consequence of a transitional interruption of the photoelectron return current towards the portion of the antenna located within the expanding cloud.  相似文献   

Multi-decadal scenario simulation over Korea using a one-way double-nested regional climate model system. Part 2: future climate projection (2021–2050)     

Eun-Soon Im  Joong-Bae Ahn  Won-Tae Kwon  Filippo Giorgi 《Climate Dynamics》2008,30(2-3):239-254

An analysis of simulated future surface climate change over the southern half of Korean Peninsula using a RegCM3-based high-resolution one-way double-nested system is presented. Changes in mean climate as well as the frequency and intensity of extreme climate events are discussed for the 30-year-period of 2021–2050 with respect to the reference period of 1971–2000 based on the IPCC SRES B2 emission scenario. Warming in the range of 1–4°C is found throughout the analysis region and in all seasons. The warming is maximum in the higher latitudes of the South Korean Peninsula and in the cold season. A large reduction in snow depth is projected in response to the increase of winter minimum temperature induced by the greenhouse warming. The change in precipitation shows a distinct seasonal variation and a substantial regional variability. In particular, we find a large increase of wintertime precipitation over Korea, especially in the upslope side of major mountain systems. Summer precipitation increases over the northern part of South Korea and decreases over the southern regions, indicating regional diversity. The precipitation change also shows marked intraseasonal variations throughout the monsoon season. The temperature change shows a positive trend throughout 2021–2050 while the precipitation change is characterized by pronounced interdecadal variations. The PDF of the daily temperature is shifted towards higher values and is somewhat narrower in the scenario run than the reference one. The number of frost days decreases markedly and the number of hot days increases. The regional distribution of heavy precipitation (over 80 mm/day) changes considerably, indicating changes in flood vulnerable regions. The climate change signal shows pronounced fine scale signal over Korea, indicating the need of high-resolution climate simulations  相似文献   

A search for the progenitors of two Type Ia Supernovae in NGC 1316     

Dan Maoz  Filippo Mannucci 《Monthly notices of the Royal Astronomical Society》2008,388(1):421-428

Recent evidence of a young progenitor population for many Type Ia supernovae (SNe Ia) raises the possibility that evolved intermediate-mass progenitor stars may be detected in pre-explosion images. NGC 1316, a radio galaxy in the Fornax cluster, is a prolific producer of SNe Ia, with four detected since 1980. We analyse Hubble Space Telescope ( HST ) pre-explosion images of the sites of two of the SNe Ia that exploded in this galaxy, SN2006dd (a normal Type Ia) and SN2006mr (likely a subluminous, 1991bg-like, SN Ia). Astrometric positions are obtained from optical and near-infrared ground-based images of the events. We find no candidate point sources at either location, and set upper limits on the flux in B, V and I from any such progenitors. We also estimate the amount of extinction that could be present, based on analysis of the surface-brightness inhomogeneities in the HST images themselves. At the distance of NGC 1316, the limits correspond to absolute magnitudes of  ∼−5.5, −5.4  and −6.0 mag in   M _B , M _V   and   M _I   , respectively. Comparison to stellar evolution models argues against the presence at the supernova sites, 3 yr prior to the explosion, of normal stars with initial masses  ≳6 M_⊙  at the tip of their asymptotic-giant branch (AGB) evolution, young post-AGB stars that had initial masses  ≳4 M_⊙  and post-red giant stars of initial masses  ≳9 M_⊙  .  相似文献