Are Boltzmann plots of hydrogen Balmer lines a tool for identifying a subclass of S1 AGN?

It is becoming clear that we can define two different types of nearby AGN belonging to the Seyfert 1 class (S1), on the basis of the match of the intensities of their Broad Balmer Lines (BBL) with the Boltzmann Plots (BP). These two types of S1 galaxies, that we call BP-S1 and NoBP-S1, are characterized, in first approximation, by Broad Line Regions (BLR) with different structural and physical properties. In this communication, we show that these features can be well pointed out by a multi-wavelength analysis of the continuum and of the broad recombination Hydrogen lines, that we carry out on a sample of objects detected at optical and X-ray frequencies. The investigation is addressed to verify whether BP-S1 are the ideal candidates for the study of the kinematical and structural properties of the BLR, in order to derive reliable estimates of the mass of their central engine and to constrain the properties of their nuclear continuum spectrum.     

一种飞-续-飞随机谱的编制方法及软件

本文介绍了一种飞-续-飞随机谱的编制方法和软件。它以空测的重心过载数据为基础,经过数据处理后,建立对应于每个飞行任务的Markov矩阵。并调整统计平均后的Markov矩阵以保证可得到一个不中断的过载序列。然后从矩阵中抽取半循环序列,构成飞-续-飞随机谱。本文中讨论了矩阵中半循环的随机抽取方法,给出了应用实例。     

The Lunar Orbiter Laser Altimeter Investigation on the Lunar Reconnaissance Orbiter Mission

The Lunar Orbiter Laser Altimeter (LOLA) is an instrument on the payload of NASA’s Lunar Reconnaissance Orbiter spacecraft (LRO) (Chin et al., in Space Sci. Rev. 129:391–419, 2007). The instrument is designed to measure the shape of the Moon by measuring precisely the range from the spacecraft to the lunar surface, and incorporating precision orbit determination of LRO, referencing surface ranges to the Moon’s center of mass. LOLA has 5 beams and operates at 28 Hz, with a nominal accuracy of 10 cm. Its primary objective is to produce a global geodetic grid for the Moon to which all other observations can be precisely referenced.     

Evidence of a cyclotron line at 70 keV from 4U0531+21

The HXR79 hard X-Ray experiment was flown the August 26th 1979 from the Milo Base (Sicily, Italy) and a 27-hour flight was achieved. The scientific payload consisted of two Multiwire Spectroscopic Proportional Counters (MWSPC) with 900 cm² sensitive geometric area each, in the hard X-Ray range (16–180 keV). A single drift scan was performed on the Crab Nebula region after the balloon reached the flotation point (2.9 mbar). The observation gave a maximum counting rate of about 25 counts/s superimposed on a background of about 75 counts/s. The Crab power-law spectrum was observed, and these data provide evidence for a line emission enhancement around 70 keV.     

Performance analysis and mission applications of a new solar sail concept based on crossed booms with tip-deployed membranes

For precursor solar sail activities a strategy for a controlled deployment of large membranes was developed based on a combination of zig-zag folding and coiling of triangular sail segments spanned between crossed booms. This strategy required four autonomous deployment units that were jettisoned after the deployment is completed. In order to reduce the complexity of the system an adaptation of that deployment strategy is investigated.A baseline design for the deployment mechanisms is established that allows the deployment actuation from a central bus system in order to reduce the complexity of the system. The mass of such a sail craft will be slightly increased but its performance is still be reasonable for first solar sail missions.The presented design will be demonstrated on breadboard level showing the feasibility of the deployment strategy. The characteristic acceleration will be evaluated and compared to the requirements of certain proposed solar sail missions.     

Gravity field models from kinematic orbits of CHAMP,GRACE and GOCE satellites

The aim of our work is to generate Earth’s gravity field models from GPS positions of low Earth orbiters. Our inversion method is based on Newton’s second law, which relates the observed acceleration of the satellite with forces acting on it. The observed acceleration is obtained as numerical second derivative of kinematic positions. Observation equations are formulated using the gradient of the spherical harmonic expansion of the geopotential. Other forces are either modelled (lunisolar perturbations, tides) or provided by onboard measurements (nongravitational perturbations). From this linear regression model the geopotential harmonic coefficients are obtained.     

Monitoring coastal sea level using reflected GNSS signals

A continuous monitoring of coastal sea level changes is important for human society since it is predicted that up to 332 million people in coastal and low-lying areas will be directly affected by flooding from sea level rise by the end of the 21st century. The traditional way to observe sea level is using tide gauges that give measurements relative to the Earth’s crust. However, in order to improve the understanding of the sea level change processes it is necessary to separate the measurements into land surface height changes and sea surface height changes. These measurements should then be relative to a global reference frame. This can be done with satellite techniques, and thus a GNSS-based tide gauge is proposed. The GNSS-based tide gauge makes use of both GNSS signals that are directly received and GNSS signals that are reflected from the sea surface. An experimental installation at the Onsala Space Observatory (OSO) shows that the reflected GNSS signals have only about 3 dB less signal-to-noise-ratio than the directly received GNSS signals. Furthermore, a comparison of local sea level observations from the GNSS-based tide gauge with two stilling well gauges, located approximately 18 and 33 km away from OSO, gives a pairwise root-mean-square agreement on the order of 4 cm. This indicates that the GNSS-based tide gauge gives valuable results for sea level monitoring.     

Whole lichen thalli survive exposure to space conditions: results of Lithopanspermia experiment with Aspicilia fruticulosa

The Lithopanspermia space experiment was launched in 2007 with the European Biopan facility for a 10-day spaceflight on board a Russian Foton retrievable satellite. Lithopanspermia included for the first time the vagrant lichen species Aspicilia fruticulosa from Guadalajara steppic highlands (Central Spain), as well as other lichen species. During spaceflight, the samples were exposed to selected space conditions, that is, the space vacuum, cosmic radiation, and different spectral ranges of solar radiation (λ?≥?110, ≥200, ≥290, or ≥400?nm, respectively). After retrieval, the algal and fungal metabolic integrity of the samples were evaluated in terms of chlorophyll a fluorescence, ultrastructure, and CO(2) exchange rates. Whereas the space vacuum and cosmic radiation did not impair the metabolic activity of the lichens, solar electromagnetic radiation, especially in the wavelength range between 100 and 200?nm, caused reduced chlorophyll a yield fluorescence; however, there was a complete recovery after 72?h of reactivation. All samples showed positive rates of net photosynthesis and dark respiration in the gas exchange experiment. Although the ultrastructure of all flight samples showed some probable stress-induced changes (such as the presence of electron-dense bodies in cytoplasmic vacuoles and between the chloroplast thylakoids in photobiont cells as well as in cytoplasmic vacuoles of the mycobiont cells), we concluded that A. fruticulosa was capable of repairing all space-induced damage. Due to size limitations within the Lithopanspermia hardware, the possibility for replication on the sun-exposed samples was limited, and these first results on the resistance of the lichen symbiosis A. fruticulosa to space conditions and, in particular, on the spectral effectiveness of solar extraterrestrial radiation must be considered preliminary. Further testing in space and under space-simulated conditions will be required. Results of this study indicate that the quest to discern the limits of lichen symbiosis resistance to extreme environmental conditions remains open.