2,173 research outputs found

    Detection techniques for tenuous planetary atmospheres Semiannual report, 1 Jul. - 31 Dec. 1968

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    Absorption and desorption of oxygen by zinc oxide film irradiated by ultraviolet ligh

    Detection techniques for tenuous planetary atmospheres Semiannual report, 1 Jan. - 30 Jun. 1970

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    Developing techniques and detectors for analysis of planetary atmosphere

    Detection techniques for tenuous planetary atmospheres

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    The application of detectors developed for analysis of planetary atmospheres under partial vacuum conditions, and data obtained during dust charging studies to various industrial problems is summarized. A specialized apparatus for dust measurements on a planetary lander was designed with the capability of measuring ambient dust density as a function of particle size, as well as for observing the charge of the collected dust. the optical system operates on an intermittent basis and requires only low power. No radioactive source or delicate detection equipment is required. Advances in monitoring catalyst operation by means of exoelection emission are also reported

    A multipoint field ionization source Final report, 11 Nov. 1966 - 12 Apr. 1968

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    Experimental study on use of field ionization and electron emission as ion sources for mass spectrometer

    Detection techniques for tenuous planetary atmospheres Fifth six-month report, 1 Jul. - 30 Dec. 1965

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    Physical methods description for detection and analysis of tenuous planetary atmospheric component gases, especially water vapo

    The subarcsecond mid-infrared view of local active galactic nuclei: II. The mid-infrared--X-ray correlation

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    We present an updated mid-infrared (MIR) versus X-ray correlation for the local active galactic nuclei (AGN) population based on the high angular resolution 12 and 18um continuum fluxes from the AGN subarcsecond MIR atlas and 2-10 keV and 14-195 keV data collected from the literature. We isolate a sample of 152 objects with reliable AGN nature and multi-epoch X-ray data and minimal MIR contribution from star formation. Although the sample is not homogeneous or complete, we show that our results are unlikely to be affected by biases. The MIR--X-ray correlation is nearly linear and within a factor of two independent of the AGN type and the wavebands used. The observed scatter is <0.4 dex. A possible flattening of the correlation slope at the highest luminosities probed (~ 10^45 erg/s) is indicated but not significant. Unobscured objects have, on average, an MIR--X-ray ratio that is only <= 0.15 dex higher than that of obscured objects. Objects with intermediate X-ray column densities (22 < log N_H < 23) actually show the highest MIR--X-ray ratio on average. Radio-loud objects show a higher mean MIR--X-ray ratio at low luminosities, while the ratio is lower than average at high luminosities. This may be explained by synchrotron emission from the jet contributing to the MIR at low-luminosities and additional X-ray emission at high luminosities. True Seyfert 2 candidates and double AGN do not show any deviation from the general behaviour. Finally, we show that the MIR--X-ray correlation can be used to verify the AGN nature of uncertain objects. Specifically, we give equations that allow to determine the intrinsic 2-10 keV luminosities and column densities for objects with complex X-ray properties to within 0.34 dex. These techniques are applied to the uncertain objects of the remaining AGN MIR atlas, demonstrating the usefulness of the MIR--X-ray correlation as an empirical tool.Comment: Accepted for publication in MNRAS, 40 pages, 25 figure

    Detection techniques for tenuous planetary atmospheres

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    Electrostatic charging of dust and its effect on planetary atmospheres is discussed, along with its applications to Martian atmosphere. Laboratory and field experiments in dust storms indicate that the major atmospheric parameters on Mars include: (1) pressure, temperature, and relative humidity; (2) wind velocity and direction; (3) particulate size and composition; and (4) electrostatic charge and field gradient. Various instrumentation techniques adapted for a Mars Lander are briefly reviewed. The effect of exoelectron emission on surface catalysis is studied

    Detection techniques for tenuous planetary atmospheres Semiannual report, 1 Jul. - 31 Dec. 1970

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    Development and characteristics of detectors for analysis of planetary atmosphere

    Differential interferometry of QSO broad-line regions - I. Improving the reverberation mapping model fits and black hole mass estimates

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    Reverberation mapping (RM) estimates the size and kinematics of broad-line regions (BLR) in quasars and type I AGNs. It yields size–luminosity relation to make QSOs standard cosmological candles, and mass–luminosity relation to study the evolution of black holes and galaxies. The accuracy of these relations is limited by the unknown geometry of the BLR clouds distribution and velocities. We analyse the independent BLR structure constraints given by super-resolving differential interferometry. We developed a three-dimensional BLR model to compute all differential interferometry and RM signals. We extrapolate realistic noises from our successful observations of the QSO 3C 273 with AMBER on the VLTI. These signals and noises quantify the differential interferometry capacity to discriminate and measure BLR parameters including angular size, thickness, spatial distribution of clouds, local-to-global and radial-to-rotation velocity ratios, and finally central black hole mass and BLR distance. A Markov Chain Monte Carlo model-fit, of data simulated for various VLTI instruments, gives mass accuracies between 0.06 and 0.13?dex, to be compared to 0.44?dex for RM mass–luminosity fits. We evaluate the number of QSOs accessible to observe with current (AMBER), upcoming (GRAVITY) and possible (OASIS with new generation fringe trackers) VLTI instruments. With available technology, the VLTI could resolve more than 60 BLRs, with a luminosity range larger than four decades, sufficient for a good calibration of RM mass–luminosity laws, from an analysis of the variation of BLR parameters with luminosity
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