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Sample records for affects surface photometry

  1. ESP -- Extended Surface Photometry

    NASA Astrophysics Data System (ADS)

    Gray, Norman; Taylor, Mark; Privett, Grant

    ESP (Extended Surface Photometry) is a package of application programs developed to allow you to determine the photometric properties of galaxies and other extended objects. It has applications that: detect flatfielding faults, remove cosmic rays, median filter images, determine image statistics, determine local background values, perform galaxy profiling, fit 2-D Gaussian profiles to galaxies, generate pie slice cross-sections of galaxies and display profiling results.

  2. ESP: Extended Surface Photometry

    NASA Astrophysics Data System (ADS)

    Privett, Grant; Taylor, Mark; Gray, Norman; Draper, Peter W.; Jenness, Tim

    2014-05-01

    ESP (Extended Surface Photometry) determines the photometric properties of galaxies and other extended objects. It has applications that detect flatfielding faults, remove cosmic rays, median filter images, determine image statistics and local background values, perform galaxy profiling, fit 2-D Gaussian profiles to galaxies, generate pie slice cross-sections of galaxies, and display profiling results. It is distributed as part of the Starlink software collection (ascl:1110.012)

  3. Surface photometry of WINGS galaxies with GASPHOT

    NASA Astrophysics Data System (ADS)

    D'Onofrio, M.; Bindoni, D.; Fasano, G.; Bettoni, D.; Cava, A.; Fritz, J.; Gullieuszik, M.; Kjærgaard, P.; Moretti, A.; Moles, M.; Omizzolo, A.; Poggianti, B. M.; Valentinuzzi, T.; Varela, J.

    2014-12-01

    Aims: We present the B, V, and K band surface photometry catalogs obtained by running the automatic software GASPHOT on galaxies from the WINGS cluster survey with isophotal areas larger than 200 pixels. The catalogs can be downloaded at the Centre de Données Astronomiques de Strasbourg. Methods: The luminosity growth curves of stars and galaxies in a given catalog relative to a given cluster image were obtained simultaneously by slicing the image with a fixed surface brightness step in several SExtractor runs. Then, using a single Sersic law convolved with a space-varying point spread function (PSF), GASPHOT performed a simultaneous χ2 best-fit of the major- and minor-axis luminosity growth curves of galaxies. We outline the GASPHOT performances and compare our surface photometry with that obtained by SExtractor, GALFIT, and GIM2D. This analysis is aimed at providing statistical information about the accuracy that is generally achieved by the softwares for automatic surface photometry of galaxies. Results: The GASPHOT catalogs provide the parameters of the Sersic law that fit the luminosity profiles for each galaxy and for each photometric band. They are the sky coordinates of the galaxy center (RA, Dec), the total magnitude (m), the semi-major axis of the effective isophote (Re), the Sersic index (n), the axis ratio (b/a), and a flag parameter (QFLAG) that generally indicates the fit quality. The WINGS-GASPHOT database includes 41 463 galaxies in the B band, 42 275 in the V band, and 71 687 in the K band. The bright early-type galaxies have higher Sersic indices and larger effective radii, as well as redder colors in their center. In general, the effective radii increase systematically from the K to the V and B band. Conclusions: The GASPHOT photometry agrees well with the surface photometry obtained by GALFIT and GIM2D, and with the aperture photometry provided by SExtractor. In particular, the direct comparison of structural parameters derived by different softwares for common galaxies indicates that the systematic differences are small in general. The only significant deviations are most likely due to the peculiar (and very accurate) image processing adopted by WINGS for large galaxies. The main advantages of GASPHOT with respect to other tools are (i) the automatic finding of the local PSF; (ii) the short CPU execution time; and (iii) the remarkable stability against the choice of the initial-guess parameters. All these characteristics make GASPHOT an ideal tool for blind surface photometry of large galaxy samples in wide-field CCD mosaics. Catalogs are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/572/A87

  4. Automated surface photometry for the Coma Cluster galaxies: The catalog

    NASA Technical Reports Server (NTRS)

    Doi, M.; Fukugita, M.; Okamura, S.; Tarusawa, K.

    1995-01-01

    A homogeneous photometry catalog is presented for 450 galaxies with B(sub 25.5) less than or equal to 16 mag located in the 9.8 deg x 9.8 deg region centered on the Coma Cluster. The catalog is based on photographic photometry using an automated surface photometry software for data reduction applied to B-band Schmidt plates. The catalog provides accurate positions, isophotal and total magnitudes, major and minor axes, and a few other photometric parameters including rudimentary morphology (early of late type).

  5. BVRI SURFACE PHOTOMETRY OF ISOLATED GALAXY TRIPLETS

    SciTech Connect

    Hernandez-Toledo, H. M.; Mendez-Hernandez, H.; Aceves, H.; OlguIn, L. E-mail: hmendez@astroscu.unam.mx E-mail: lorenzo@astro.uson.mx

    2011-03-15

    Optical broadband BVRI observations of 54 galaxies selected from the Catalog of Isolated Triplets of Galaxies in the Northern Hemisphere have been carried out at San Pedro Martir National Observatory to evaluate their photometric and morphological properties. We complement our analysis with Two-Micron All Sky Survey (2MASS) and Sloan Digital Sky Survey (SDSS) images and look for signatures likely related to interactions/mergers. We report apparent/absolute BVRI magnitudes and colors for the 54 galaxies. The membership of these galaxies is re-evaluated by imposing a reasonable condition of concordant redshifts upon the original selection criteria, rendering a final sample of 34 galaxies in 13 triplets, 12 galaxies in close pairs, and 8 galaxy outliers. The triplets are spiral-dominated systems in different dynamical stages from loosely interacting to almost merged objects. The incidence fraction of features likely associated with interactions is {approx}56%, similar to those found in northern and southern compact groups. The average fraction of bars is 35% with a mean value of maximum bar ellipticity {epsilon}{sub max} {approx} 0.4. Bars are hosted in the late-type triplet spirals, almost twice more than in early-type spirals. The global fraction of rings is 20%, all in the late-type components. The overdensity of triplets with respect to the background and their current dynamical status, as devised from our estimate of their dynamical parameters, namely the harmonic radius R{sub H} , velocity dispersion {sigma}, dimensionless crossing time H{sub 0{tau}c}, and virial mass M{sub V} , appear to be sufficient to favor galaxy transformations similar to those seen in dense groups and clusters. By contrast, the lower fraction of bonafide ellipticals and the relatively higher fraction of late-type spirals make these triplets essentially different from the Hickson Compact Groups and more representative of the field. A modest 1.6 enhancement factor in the optical luminosity of the late-type triplet components relative to an isolated galaxy control sample is also interpreted as consistent with interactions in physically bounded aggregates. Our results lead us to suggest that non-negligible populations of physical triplets might be found in complete and well-observed samples. We provide individual mosaics for the 54 galaxies containing (1) logarithmic-scaled R-band images, (2) R-band sharp/filtered images, (3) (B - I) color index maps, (4) RGB images from the SDSS database, (5) co-added J + H + K images generated from the 2MASS archives that were also sharp/filtered, and (6) {epsilon}, position angle radial profiles from a surface photometry analysis of (a) the R band and (b) the co-added near-infrared images, all used for the present analysis.

  6. Surface photometry of comets: outlook for small telescopes

    NASA Astrophysics Data System (ADS)

    Sizonenko, Yu. V.

    2000-09-01

    The small telescopes of observatories in Ukraine have one useful characteristic, which can give a new life for these instruments. With wide angle astrographs and cameras one can obtain the images of extended sky objects for different purposes, in particular for studies of surface brightness distributions. The examples of successful use of the results of surface photometry of comets are presented.

  7. The photometry of flat, basaltic surfaces

    NASA Technical Reports Server (NTRS)

    Weaver, W. R.; Meador, W. E.

    1977-01-01

    A photometer was developed and successfully operated to obtain photometric measurements on several flat, particulate surfaces of basalt for coplanar scattering geometries. The test materials were two size ranges each of two different basalts with significantly different albedos. The measurements include a range of phase angles from 30 to 80 degrees and were obtained by varying the angles of incidence and emission such that the phase angle remained constant. The data were used elsewhere in the verification of the Meador-Weaver photometric function and are presented here in the form of Minnaert plots. In this form the data offered the first support for the accuracy of the Meador-Weaver photometric function because of a deviation of the data from a straight line trend at larger departures from the mirror point geometry. This trend is predicted by the Meador-Weaver function but not by the Minnaert function. The failure of photometric data to support the Minnaert function was not evident in earlier measurements because of the restriction of planetary data to small departures from the mirror point geometry and to small values of the phase angle.

  8. Surface photometry of a sample of elliptical and S0 galaxies

    SciTech Connect

    De carvalho, R.R.; Da costa, L.N.; Djorgovski, S. California Institute of Technology, Pasadena )

    1991-08-01

    The results are reported of surface photometry of 38 early-type galaxies, located mainly in the Fornax Cluster. Detailed comparisons with previously published work are given along with internal and external error estimates for all quantities, and some serious systematic discrepancies in the older aperture photometry of some of the galaxies in the present sample are pointed out. 15 refs.

  9. Photographic surface photometry of the Milky Way. III - Photometry of the central area of the Galaxy in the ultraviolet

    NASA Astrophysics Data System (ADS)

    Proell, H. J.; Schmidt-Kaler, T.; Schlosser, W.

    1983-01-01

    6 photographic plates, taken at La Silla, Chile, with the spherical mirror super-wide-angle camera of the Astronomisches Institut der Ruhr Universität Bochum (see paper I: Schmidt-Kaler, Th. et al., 1982) were measured to study the surface brightness distribution in the area around the centre of the Milky Way, between galactic longitudes 297° and 27°, and latitudes - 30° to + 30°, with an angular resolution of 0.°3 × 0.°3 (Fig. 5). In section 2 the plate material and details of the reductions are presented, so far as not already given in paper I. During the photometric scanning of the plates all stars brighter than a limiting magnitude mlim were marked by hand, and the corresponding data points were replaced by an average from neighbouring points (section 3). Defined at the level of 50% elimination, mlim ≌ 8.m0 (in U). Figure 4 shows the effect of various methods of eliminating bright stars. The errors of the surface photometry are discussed in section 4. The internal mean error of the intensity of one data point, as determined from the scatter from the 6 plates, is ± 9.4%. This error is split into an additive component ± 8 S10U (S10 = intensity of a star of 10m), mostly due to the contributions of airglow and scattered light, and a multiplicative component of ± 7.5%, mostly due to the uncertainty of the photographic characteristic curve. Possible systematic errors are estimated and upper limits for these are given in table II. Section 5 presents the results of the photometry. For the sake of clear representation in the isophote map (Fig 5) data with intermediate intensities 110 < Igal ≦ 250 S10U were smoothed over 0.°9 × 0.°9, data with Igal ≦ 110 S10U were smoothed over 1.°2 × 1.°2. The mean error of the isophotes is about ± 6%. We then compare our photometry with existing ultraviolet surface photometries. Apart from the area l = 320° to 330°, b = -25° to -20° where our intensities are probably vitiated by some remaining airglow influence, there is generally very good agreement with the results of Seidensticker, Schinidt-Kaler and Schlosser (= paper II), their values being smaller by a statistically insignificant additive difference of -14(± 15) S10U. The comparison (Fig 6) with the photoelectric surface photometry of Pfleiderer and Mayer (1971) shows a negligible additive difference of -8 (± 12) S10U, but a large scale difference of 24(± 9)%, the Bochum values being larger. The comparison with the measurements of Leinert and Richter (1981), obtained by the satellite Helios, shows very good agreement in the run of the intensities (Fig. 7). Computation of a point by point correlation reveals their values being smaller by an additive difference of -5 (± 2) S10U and a scale difference of 17(± 2)%. As obvious from figure 7 the main difference in the two photometry results from the finer structures in our data, due to different resolution and different completeness in eliminating background stars. Thus we constructed a lower envelope to our data. This reveals an additive difference of 0 (± 0.3) S10U and a scale difference of 2.4 (± 9)% in the same sense as above. In the last paragraph we discuss the structure of the Milky Way central region in U, in particular those spiral filaments which appear inclined to the galactic equator (shingles, corrugations). The three shingles discovered by Schmidt-Kaler and Schlosser (1973) in the next-inner spiral arm-I and an additional feature appear if the data-field of the UV photometry is spatially differentiated (Fig. 8).

  10. Surface photometry of comet West 1976 VI picture

    NASA Astrophysics Data System (ADS)

    Sizonenko, Iu. V.

    Photometric data from a photograph of comet West 1976 VI, obtained in a 3-min exposure using the wide-angle camera at the high-altitude station of the Main Astronomical Observatory of the Ukrainian Academy of Sciences on March 12, 1976, are reported. The calibration is based on the radioluminescence light sources, and photometry is performed using a microphotometer with pixel size 48 x 12 arcsec and density-to-brightness transformation accuracy 0.8 percent. The brightness-decrease laws for the type I and type II tails have log B = -1.771 log R - 4.186 and log B = -1.769 log R -4.385, respectively.

  11. Planetary surface photometry and imaging: progress and perspectives.

    PubMed

    Goguen, Jay D

    2014-10-01

    Spacecraft have visited and returned many thousands of images and spectra of all of the planets, many of their moons, several asteroids, and a few comet nuclei during the golden age of planetary exploration. The signal in each pixel of each image or spectral channel is a measurement of the radiance of scattered sunlight into a specific direction. The information on the structure and composition of the surface that is contained in variation of the radiance with scattering geometry and wavelength, including polarization state, has only just begun to be exploited and is the topic of this review. The uppermost surfaces of these bodies are mainly composed of particles that are continuously generated by impacts of micrometeoroids and larger impactors. Models of light scattering by distributions of sizes and irregular shapes of particles and by closely packed particles within a surface are challenging. These are active topics of research where considerable progress has recently been made. We focus on the surfaces of bodies lacking atmospheres.These surfaces are diverse and their morphologies give evidence of their evolution by impacts and resurfacing by a variety of processes including down slope movement and electrostatic transport of particles, gravitational accumulation of debris, volatile outgassing and migration, and magnetospheric interactions. Sampling of scattering geometries and spatial resolution is constrained by spacecraft trajectories. However, the large number of archived images and spectra demand more quantitative interpretation. The scattering geometry dependence of the radiance is underutilized and promises constraints on the compositions and structure of the surface for materials that lack diagnostic wavelength dependence. The general problem is considered in terms of the lunar regolith for which samples have been returned to Earth. PMID:25313169

  12. Planetary surface photometry and imaging: progress and perspectives

    NASA Astrophysics Data System (ADS)

    Goguen, Jay D.

    2014-10-01

    Spacecraft have visited and returned many thousands of images and spectra of all of the planets, many of their moons, several asteroids, and a few comet nuclei during the golden age of planetary exploration. The signal in each pixel of each image or spectral channel is a measurement of the radiance of scattered sunlight into a specific direction. The information on the structure and composition of the surface that is contained in variation of the radiance with scattering geometry and wavelength, including polarization state, has only just begun to be exploited and is the topic of this review. The uppermost surfaces of these bodies are mainly composed of particles that are continuously generated by impacts of micrometeoroids and larger impactors. Models of light scattering by distributions of sizes and irregular shapes of particles and by closely packed particles within a surface are challenging. These are active topics of research where considerable progress has recently been made. We focus on the surfaces of bodies lacking atmospheres. These surfaces are diverse and their morphologies give evidence of their evolution by impacts and resurfacing by a variety of processes including down slope movement and electrostatic transport of particles, gravitational accumulation of debris, volatile outgassing and migration, and magnetospheric interactions. Sampling of scattering geometries and spatial resolution is constrained by spacecraft trajectories. However, the large number of archived images and spectra demand more quantitative interpretation. The scattering geometry dependence of the radiance is underutilized and promises constraints on the compositions and structure of the surface for materials that lack diagnostic wavelength dependence. The general problem is considered in terms of the lunar regolith for which samples have been returned to Earth.

  13. Surface photometry of the anomalous tail of comet Bradfield 1987 XXIX.

    NASA Astrophysics Data System (ADS)

    Sizonenko, Yu. V.

    1996-01-01

    A short sunward spike in comet Bradfield 1987 XXIX is shown to be a true anomalous tail. The structure observed from 8 through 19 January 1988 was formed by particles bigger than 0.2 mm ejected at a distance of 1.031 AU from the Sun 37.6 days before the perihelion passage. Surface photometry of six plates of the comet produced its isophotes as well as longitudinal and transverse scans of the anomalous tail.

  14. Balloon-borne infrared telescope for absolute surface photometry of the night sky.

    PubMed

    Hofmann, W; Lemke, D; Thum, C

    1977-12-01

    A dry ice cooled 15-cm ir telescope was used on board the balloon-borne gondola THISBE for absolute surface photometry of the Milky Way, the zodiacal light, and the airglow in the PbS wavelength region. The mechanical, optical, electronical, and thermal design of the instrument is described. The efficiency of the baffle system for suppression of stray light from earth and balloon is discussed in detail. Recent airglow measurements are presented. PMID:20174314

  15. Surface Photometry of Comet Hale-Bopp Carbon Images

    NASA Astrophysics Data System (ADS)

    Sizonenko, Yu. V.

    1997-07-01

    A very long series of photographic observations of the comet Hale-Bopp has been made during January April 1997 at the double astrograph (400/2000) of the Main Astronomical Observatory (Kyiv, Ukraine). Some of the cometary photos were obtained with two wide-band filter combinations. One of these combinations isolates C2 emission, another — the nearby dust continuum. The images were digitized by means of AMDPH-XY machine and then calibrated following the standard procedure. After subtraction of the dust continuum the distribution of surface brightness in the C2 emission coma of comet Hale-Bopp was studied. We found an asymmetric brightness distribution both pre- and post-perihelion. On 21.77 April 1997 a secondary brightness peak is found at the distance of 1.03 × 105 km from the nucleus. It is possible that this peak is related to the extended source of the C2 molecules.

  16. Imaging Surface Spots from Space-Borne Photometry

    NASA Astrophysics Data System (ADS)

    Lanza, A. F.

    2016-04-01

    A general introduction to the foundations of spot modelling is given. It considers geometric models of the surface brightness distribution in late-type stars as can be derived from their wide-band optical light curves. Spot modelling is becoming more and more important thanks to the high-precision, high duty-cycle photometric time series made available by space-borne telescopes designed to search for planets through the method of transits. I review approaches based on a few spots as well as more sophisticated techniques that assume a continuous distributions of active regions and adopt regularization methods developed to solve ill-posed problems. The use of transit light curves to map spots occulted by a planet as it moves across the disc of its host star is also briefly described. In all the cases, the main emphasis is on the basic principles of the modelling techniques and on their testing rather than on the results obtained from their application.

  17. Studying Titan's surface photometry in the 5 microns atmospheric window with the Cassini/VIMS instrument

    NASA Astrophysics Data System (ADS)

    Cornet, T.; Altobelli, N.; Sotin, C.; Le Mouelic, S.; Rodriguez, S.; Philippe, S.; Brown, R. H.; Barnes, J. W.; Buratti, B. J.; Baines, K. H.; Clark, R. N.; Nicholson, P. D.

    2014-12-01

    Due to the influence of methane gas and a thick aerosols haze in the atmosphere, Titan's surface is only visible in 7 spectral atmospheric windows centered at 0.93, 1.08, 1.27, 1.59, 2.01, 2.7-2.8 and 5 microns with the Cassini Visual and Infrared Mapping Spectrometer (VIMS). The 5 microns atmospheric window constitutes the only one being almost insensitive to the haze scattering and which presents only a reduced atmospheric absorption contribution to the signal recorded by the instrument. Despite these advantages leading to the almost direct view of the surface, the 5 microns window is also the noisiest spectral window of the entire VIMS spectrum (an effect highly dependent on the time exposure used for the observations), and it is not totally free from atmospheric contributions, enough to keep "artefacts" in mosaics of several thousands of cubes due to atmospheric and surface photometric effects amplified by the very heterogeneous viewing conditions between each Titan flyby. At first order, a lambertian surface photometry at 5 microns has been used as an initial parameter in order to estimate atmospheric opacity and surface photometry in all VIMS atmospheric windows and to determine the albedo of the surface, yet unknown, both using radiative transfer codes on single cubes or empirical techniques on global hyperspectral mosaics. Other studies suggested that Titan's surface photometry would not be uniquely lambertian but would also contain anisotropic lunar-like contributions. In the present work, we aim at constraining accurately the surface photometry of Titan and residual atmospheric absorption effects in this 5 microns window using a comprehensive study of relevant sites located at various latitudes. Those include bright and dark (dunes) terrains, 5-microns bright terrains (Hotei Regio and Tui Regio), the Huygens Landing Site and high latitudes polar lakes and seas. The VIMS 2004 to 2014 database, composed of more than 40,000 hyperspectral cubes acquired on Titan, has been decomposed into a MySQL relational database in order to perform the present study looking at both spatial and temporal (seasonal) aspects.

  18. Radiative transfer in the surfaces of atmosphereless bodies. III - Interpretation of lunar photometry

    NASA Technical Reports Server (NTRS)

    Lumme, K.; Irvine, W. M.

    1982-01-01

    Narrowband and UBV photoelectric phase curves of the entire lunar disk and surface photometry of some craters have been interpreted using a newly developed generalized radiative transfer theory for planetary regoliths. The data are well fitted by the theory, yielding information on both macroscopic and microscopic lunar properties. Derived values for the integrated disk geometric albedo are considerably higher than quoted previously, because of the present inclusion of an accurately determined opposition effect. The mean surface roughness, defined as the ratio of the height to the radius of a typical irregularity, is found to be 0.9 + or - 0.1, or somewhat less than the mean value of 1.2 obtained for the asteroids. From the phase curves, wavelength-dependent values of the single scattering albedo and the Henyey-Greenstein asymmetry factor for the average surface particle are derived.

  19. Disk Galaxies in the Outer Local Supercluster: Optical CCD Surface Photometry and Distribution of Galaxy Disk Parameter

    NASA Technical Reports Server (NTRS)

    Lu, N. Y.

    1998-01-01

    We report new B-band CCD surface photometry on a sample of 76 disk galaxies brighter than BT = 14.5 mag in the Uppsala General Catalogue of Galaxies, which are confined within a volume located in the outer part of the Local Supercluster.

  20. HST observations of globular clusters in M 31. 1: Surface photometry of 13 objects

    NASA Technical Reports Server (NTRS)

    Pecci, F. Fusi; Battistini, P.; Bendinelli, O.; Bonoli, F.; Cacciari, C.; Djorgovski, S.; Federici, L.; Ferraro, F. R.; Parmeggiani, G.; Weir, N.

    1994-01-01

    We present the initial results of a study of globular clusters in M 31, using the Faint Object Camera (FOC) on the Hubble Space Telescope (HST). The sample of objects consists of 13 clusters spanning a range of properties. Three independent image deconvolution techniques were used in order to compensate for the optical problems of the HST, leading to mutually fully consistent results. We present detailed tests and comparisons to determine the reliability and limits of these deconvolution methods, and conclude that high-quality surface photometry of M 31 globulars is possible with the HST data. Surface brightness profiles have been extracted, and core radii, half-light radii, and central surface brightness values have been measured for all of the clusters in the sample. Their comparison with the values from ground-based observations indicates the later to be systematically and strongly biased by the seeing effects, as it may be expected. A comparison of the structural parameters with those of the Galactic globulars shows that the structural properties of the M 31 globulars are very similar to those of their Galactic counterparts. A candidate for a post-core-collapse cluster, Bo 343 = G 105, has been already identified from these data; this is the first such detection in the M 31 globular cluster system.

  1. DEEP K{sub s} -NEAR-INFRARED SURFACE PHOTOMETRY OF 80 DWARF IRREGULAR GALAXIES IN THE LOCAL VOLUME

    SciTech Connect

    Fingerhut, Robin L.; McCall, Marshall L.; Argote, Mauricio; Cluver, Michelle E.; Nishiyama, Shogo; Rekola, Rami T. F.; Richer, Michael G.; Vaduvescu, Ovidiu; Woudt, Patrick A. E-mail: mccall@yorku.c E-mail: mcluver@ipac.caltech.ed E-mail: rareko@utu.f E-mail: ovidiuv@ing.iac.e

    2010-06-10

    We present deep near-infrared (K{sub s}) images and surface photometry for 80 dwarf irregular galaxies (dIs) within {approx}5 Mpc of the Milky Way. The galaxy images were obtained at five different facilities between 2004 and 2006. The image reductions and surface photometry have been performed using methods specifically designed for isolating faint galaxies from the high and varying near-infrared sky level. Fifty-four of the 80 dIs have surface brightness profiles which could be fit to a hyperbolic-secant (sech) function, while the remaining profiles could be fit to the sum of a sech and a Gaussian function. From these fits, we have measured central surface brightnesses, scale lengths, and integrated magnitudes. This survey is part of a larger study of the connection between large-scale structure and the global properties of dIs, the hypothesized building-blocks of more massive galaxies.

  2. UIT: Ultraviolet surface photometry of the spiral galaxy M74 (NGC 628)

    NASA Technical Reports Server (NTRS)

    Cornett, Robert H.; O'Connell, Robert W.; Greason, Michael R.; Offenberg, Joel D.; Angione, Ronald J.; Bohlin, Ralph C.; Cheng, K. P.; Roberts, Morton S.; Smith, Andrew M.; Smith, Eric P.

    1994-01-01

    Ultraviolet photometry, obtained from Ultraviolet Imaging Telescope (UIT) images at 1520 A (far-UV; magnitudes m(152)) and 2490 A (near-UV; magnitudes m(249)), of the spiral galaxy M74 (NGC 628) is compared with H-alpha, R, V, and B surface photometry and with models. M74's surface brightness profiles have a central peak with an exponential falloff; the exponential scale lengths of the profiles increase with decreasing wavelength for the broad-band images. The slope of the continuum-subtracted H-alpha profile is intermediate between those of far-UV and near-UV profiles, consistent with the related origins of H-alpha and UV emission in extreme Population I material. M74's color profiles all become bluer with increasing radius. The (m(152) - m(249)) color as measured by UIT averages near 0.0 (the color of an A0 star) over the central 20 sec radius and decreases from approximately -0.2 to approximately -0.4 from 20 sec to 200 sec. The spiral arms are the dominant component of the surface photometry colors; interarm regions are slightly redder. In the UV, M74's nuclear region resembles its disk/spiral arm material in colors and morphology, unlike galaxies such as M81. No UV 'bulge' is apparent. The m(152) - m(249) colors and models of M74's central region clearly demonstrate that there is no significant population of O or B stars present in the central 10 sec. M74's UV morphology and (m(152) - m(249)) color profiles are similar to those of M33, although M74 is approximately 0.5 mag redder. M81 has a smooth UV bulge which is much redder than the nuclear regions of M74 and M33. M74 is approximately 0.4 mag bluer than M81 in its outer disk, although M81 has bright UV sources only in spiral arms more than 5 kpc from its center. We investigate possible explanations for the color profiles of the galaxies and the differences among the galaxies: abundances; reddening due to internal dust; interplanetary magnetic field (IMF) variations, and the history of formation of the dominant generations of stars. Abundance and IMF variations do not produce large enough m(152) - m(249) or UV - V color differences. Comparing model UV/optical colors with those of M74 shows that M74's disk has undergone significant star formation over the past 500 Myr, and that either the star-formation history or the extinction varies systematically across M74's disk. Comparison of M74, M33, and M81 (UV - V) colors shows that M74 colors range from the bluest of M33's colors to the bluest of M81's. The failure of reddening models to cover the range of colors, and the known abundance range in such material, leads to the conclusion that star-formation history varies significantly as a function of radius in these galaxies, and that such variation is required to explain the range of colors observed in M74, M33, and M81.

  3. BVRI surface photometry of mixed morphology pairs of galaxies. II. The second data set

    NASA Astrophysics Data System (ADS)

    Franco-Balderas, A.; Hernández-Toledo, H. M.; Dultzin-Hacyan, D.

    2004-04-01

    In order to analyze the photometric signature of gravitational interactions in spiral and elliptical galaxies, we present results of multicolor broad band (BVRI) surface photometry for a second set of 10 mixed pairs drawn from the Karachentsev Catalogue of Isolated Pairs of Galaxies (KPG). We report total magnitudes and colors, as well as surface brightness, color and geometric (ɛ, PA and a4/a) profiles. Most of this subsample have photometric parameters homogeneously derived for the first time. Internal and external data comparisons show consistency within the estimated errors. We find 1 true (E+S) pair and 4 probable (E+S) pairs ((E/S0+S) cases) in the present sample. The remaining objects include 3 lenticular-spiral (S0+S) systems, 1 spiral-spiral (S+S) pair and 1 probable spiral-spiral pair ((S0/Sa+S) case). Four lenticular galaxies show evidence of underlying (perhaps induced) structures like bars/arms. Among the spiral components, an over-representation of early (Sa-Sb) types was found. A brief discussion on the existence of a Holmberg Effect is also presented. Based on data obtained at the 0.84 m telescope of the Observatorio Astronómico Nacional (OAN), San Pedro Mártir, Baja California, México, operated by the Instituto de Astronomía, UNAM. Tables 1-3 and Figs. 3-12 are only available in electronic form at http://www.edpsciences.org

  4. Stellar populations in edge-on galaxies from deep CCD surface photometry, 1: NGC 5907

    NASA Technical Reports Server (NTRS)

    Morrison, Heather L.; Boroson, Todd A.; Harding, Paul

    1994-01-01

    We present extremely deep charge coupled device (CCD) surface photometry of the edge-on Sc galaxy NGC 5907. Our data reach reliably to a surface brightness of R=27 mag/sq arcsec, some two magnitudes fainter than any previous work. We obtained this improvement using a 2048X2048 CCD with a wide (approximately 24 min) field, which made it possible to sky subtract directly from the galaxy frame, and by taking many dark sky flatfields. Our analysis of these data, using a full 2D model fitting procedure with a detailed error model, confirm the thin disk parameters of van der Kruit & Searle (1981). In particular, we confirm that the galaxy's disk has a radial cutoff and a constant scale height with radius. We find evidence for a stellar warp in this system, which has the same orientation as the H I warp. Our deep data also confirm that NGC 5907 has no thick disk. This suggests that theories of thick disk formation from star formation in the early stages of disk collapse, or by secular heating mechanisms, are unlikely to be correct, because they would predict that every galaxy would have a thick disk. Thick disk formation from the accretion of satellite galaxies is more likely.

  5. Surface photometry of plasma tail of comet C/2001 A2 (LINEAR)

    NASA Astrophysics Data System (ADS)

    Filonenko, V.; Velichko, F.

    During 2001 Aug. 1-5 at the out-of-town observation station of the Astronomical Institute of Kharkov National University (AI KhNU) about 100 CCD-images of comet C/2001 A2 (LINEAR) had been obtained with 70-cm reflector AZT-8 using CCD-camera ST-6 and V, R filters. Distribution of surface brightness in the plasma tail of this comet had been studied by software package "IRIS", designed at the AI KNU. Diffusion model, proposed by L.M.Shulman, is used to interpret the results of relative surface photometry of this comet. Using this model, the physical parameters of comet's plasma tail (mean values of induction of magnetic field, acceleration and life's time of fluorescent particles, lengthwise and transverse diffusion coefficients et al.) are estimated. The temporal variations of these parameters during our observations are investigated. Obtained values of physical parameters of the tail of comet C/2001 A2 are comparing with values of similar parameters of plasma tails of other comets (1P/Halley (1982 U1), 67P/Churyumov-Gerasimenko and Austin (C/1982 M1)).

  6. LROC NAC Photometry as a Tool for Studying Physical and Compositional Properties of the Lunar Surface

    NASA Astrophysics Data System (ADS)

    Clegg, R. N.; Jolliff, B. L.; Boyd, A. K.; Stopar, J. D.; Sato, H.; Robinson, M. S.; Hapke, B. W.

    2014-10-01

    LROC NAC photometry has been used to study the effects of rocket exhaust on lunar soil properties, and here we apply the same photometric methods to place compositional constraints on regions of silicic volcanism and pure anorthosite on the Moon.

  7. Surface photometry of early-type galaxies in the Hubble deep field

    NASA Astrophysics Data System (ADS)

    Fasano, G.; Filippi, M.

    1998-05-01

    The detailed surface photometry of a sample of early-type galaxies in the Hubble Deep Field is presented as part of a long-term project aimed to settle strong observational constraints to the theories modelling the evolution of elliptical galaxies from the early stages. The sample has been extracted, in the V606 band, from the database provided by the ESO-STECF-HDF Group \\cite[(Couch 1996).]{Co96} The selection criteria involve the total magnitude, the number of pixels detected above the background level and an automatic star/galaxy classifier. Moreover, form visual inspection of the frames, we excluded the galaxies showing unambiguous late-type morphology. The analysis of the luminosity and geometrical profiles, carried out on the 162 candidates obeying our selection criteria, resulted in a list of 99 ``bona fide'' early-type galaxies, for which accurate total magnitudes and effective radii were computed on the basis of the equivalent luminosity profiles. The comparison with the magnitudes given by \\cite[Williams et al. (1996)]{Wi96} indicates that the automated photometry tends to underestimate the total luminosity of the ellipticals. The luminosity profiles of most of galaxies in our sample follow fairly well the de Vaucouleurs law (``Normal'' profiles). However, a relevant fraction of galaxies, even following the r(1/4) law in the main body light distribution, exhibit in the inner region a flattening of the luminosity profile not attributable to the PSF (``Flat'' profiles) or, in some cases, a complex (multi-nucleus) structure (``Merger'' profiles). A statistically significant correlation is found between the shapes of the luminosity profiles and the ellipticity distribution. In particular, the average ellipticity of galaxies belonging to the ``Flat'' and ``Merger'' classes is significantly higher than that of the ``Normal'' galaxies. Finally, even taken into account the relevant uncertainty of the outer position angle profiles, the amount of isophotal twisting of HDF ellipticals turns out to be significantly larger with respect to that of the local samples. Complete Table 1 is available electronically at the CDS at ftp 130.79.128.5 and Fig. 1 is can be accessed on the online version of the journal (http://www.edpsciences.com).

  8. The stellar content of central dominant galaxies. I - CCD surface photometry

    NASA Astrophysics Data System (ADS)

    Mackie, Glen; Visvanathan, N.; Carter, D.

    1990-08-01

    UBVRI CCD surface photometry and color gradients are presented for 10 central dominant galaxies (CDGs), comprising gE, D, and cD morphological types and covering the range of Bautz-Morgan cluster types. The mean magnitude of the color gradients to a radius of 20 kpc is in agreement with those found in recent CCD studies of bright ellipticals in Virgo. The size of the gradients are consistent with N-body model predictions in which these galaxies are formed or enhanced by merger events. Parameters such as ellipticity, position angle of the major axis, and deviation from ellipticity for eight single-nucleus CDGs are also given. All galaxies show large changes in ellipticity and position angle with radius, and can be considered similar to Kormendy's T3 class of galaxies, in which tidal effects on isophotal structure are very probable. Three out of eight single-nucleus CDGs, NGC 1399, NGC 6876 and IC 1860, show evidence of isochromal flattening inside 10 kpc. Five (three boxy, two disk) out of the eight single-nucleus CDGs display nonelliptical isophotes.

  9. THE MID-INFRARED TULLY-FISHER RELATION: SPITZER SURFACE PHOTOMETRY

    SciTech Connect

    Sorce, Jenny G.; Courtois, Helene M.; Tully, R. Brent

    2012-11-01

    The availability of photometric imaging of several thousand galaxies with the Spitzer Space Telescope enables a mid-infrared calibration of the correlation between luminosity and rotation in spiral galaxies. The most important advantage of the new calibration in the 3.6 {mu}m band, IRAC Channel 1, is photometric consistency across the entire sky. Additional advantages are minimal obscuration, observations of flux dominated by old stars, and sensitivity to low surface brightness levels due to favorable backgrounds. Roughly 3000 galaxies have been observed through Spitzer cycle 7 and images of these are available from the Spitzer archive. In cycle 8, a program called Cosmic Flows with Spitzer was initiated, which will increase the available sample of spiral galaxies with inclinations greater than 45 Degree-Sign from face-on that are suitable for distance measurements by 1274. This paper describes procedures, based on the photometry package Archangel, that are being employed to analyze both the archival and new data in a uniform way. We give results for 235 galaxies, our calibrator sample for the Tully-Fisher relation. Galaxy magnitudes are determined with uncertainties held below 0.05 mag for normal spiral systems. A subsequent paper will describe the calibration of the [3.6] luminosity-rotation relation.

  10. Near-infrared surface photometry of early-type spiral galaxies. I. Bulge and disk decomposition

    NASA Astrophysics Data System (ADS)

    Moriondo, G.; Giovanardi, C.; Hunt, L. K.

    1998-05-01

    We present near-infrared (NIR) surface photometry of a sample of 14 early-type spirals with observed rotation curves. In this first paper, we report the results of two-dimensional parametric and non-parametric decompositions to separate the bulge and disk components; the parametric bulge is modeled with a generalized exponential law of integer index n, and the disk with a simple exponential. We find that the derived bulge parameters, for a given galaxy, vary systematically with the bulge shape index n. The mean early-type bulge has a best-fit n = 2.6, and 80% of the sample has best n of 2 or 3. Bulges are rarely spherical; the median bulge intrinsic ellipticity is 0.33. The median early-type disk has (J-K)_d more than 0.1 mag bluer than the bulge, and a NIR disk surface brightness more than 1 mag arcsec(-2) brighter than later-type disks. Our data are consistent with the well-established correlation of both bulge and disk surface brightness with physical scale length, and we note that the location of bulges within this projection of the fundamental plane depends on their shape index n. In agreement with previous work, the ratios of bulge and disk scale lengths are consistent with a constant value r_e/r_d = 0.3; however, such value again depends on the bulge index n, implying that claims for a scale-free Hubble sequence may be premature. Based on observations taken at TIRGO (Gornergrat, Switzerland). TIRGO is operated by CAISMI--CNR, Arcetri, Firenze, Italy.

  11. Photometric calibration of NGS/POSS and ESO/SRC plates using the NOAO PDS measuring engine. II - Surface photometry

    NASA Technical Reports Server (NTRS)

    Cutri, Roc M.; Low, Frank J.; Guhathakurta, Puragra

    1993-01-01

    In this paper we present a method to calibrate surface photometry of faint sources measured from direct photographic plates, such as those of the NGS/POSS and ESO/SRC Sky Survey. This calibration procedure does not require scanning sensitometer spots on the plates, but instead uses measurements of the brightness profiles of many faint stars of known brightness to fit a linearized approximation to the characteristic curve. The approximation is valid for only low- to medium-density emulsions, so this technique is appropriate only for relatively faint emission. Comparison between measurements of representative extended sources on the NGS/POSS and CCD images indicates that surface photometry can be obtained from the Sky Survey plates accurate to 0.1-0.3 mag in the range mu(B) between 23 and 27 and mu(R) between 22 and 26 mag/sq arcsec.

  12. Multicolor surface photometry of a sample of low luminosity radio galaxies

    NASA Astrophysics Data System (ADS)

    Sahu, Sheetal Kumar; Pandey, S. K.; Chakradhari, N. K.; Baburao Pandge, Mahadev

    2015-08-01

    We present a detailed multiband photometric study of five galaxies, selected from a sample of low luminosity early-type galaxies from B2 sample, which have mpg = 15.7, mV = 16.5, redshifts up to 0.2, radio powers P408 = 1023 - 1026.5 W Hz-1 and between 1022 - 1025 W Hz-1 at 1.4 GHz. We have used observed BVR and Hα images from IGO 2m telescope (Pune, India) and 2m HCT, Indian Astronomical Observatory (IAO Hanle, India), and archival multiband data from SDSS (ugriz), 2MASS (JHKs ), WISE, Spitzer (mid-IR), XMM, CHANDRA (X-ray), UV (GALEX) and radio from VLA, IRAM for this study.We used standard technique of surface photometry by fitting ellipses to the isophotes for studying the distribution of light in the galaxies by studying their surface brightness profiles, ellipticity profiles, position angle profiles, variation of center of isophotes along semi-major axis, shapes of isophotes, radial color gradients, twists in isophotes and fine structure variations from smooth light profile. The obtained surface brightness profiles are fitted to the core-Sersic model for decomposing the galaxy light profiles and quantify the radial stellar distributions of the sample galaxies.The multiband color index profiles, e.g. u-g, g-r, r-i, i-z, B-R, B-V, J-Hs , J-Ks , H-Ks , R-Ks , 3.4-4.6 μm, 4.6-12 μm (mid-IR) and FUV-NUV(UV), are obtained and combined with various maps e.g . unsharp-masked images, residual maps, quotient maps, dust extinction maps, Hα emission maps, CO intensity maps, diffuse X-ray emission maps and extinction curves of the galaxies to study the morphology, properties and physical correlations of different phases (e.g cool gas, dust, ionized gas and hot gases) of Inter Stellar Medium and to examine various star formation related processes in the galaxies.

  13. RADIAL DISTRIBUTION OF STARS, GAS AND DUST IN SINGS GALAXIES. I. SURFACE PHOTOMETRY AND MORPHOLOGY

    SciTech Connect

    Munoz-Mateos, J. C.; Gil de Paz, A.; Zamorano, J. E-mail: agpaz@astrax.fis.ucm.e

    2009-10-01

    We present ultraviolet through far-infrared (FIR) surface brightness profiles for the 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). The imagery used to measure the profiles includes Galaxy Evolution Explorer UV data, optical images from Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, and Sloan Digital Sky Survey, near-IR data from Two Micron All Sky Survey, and mid- and FIR images from Spitzer. Along with the radial profiles, we also provide multi-wavelength asymptotic magnitudes and several nonparametric indicators of galaxy morphology: the concentration index (C {sub 42}), the asymmetry (A), the Gini coefficient (G), and the normalized second-order moment of the brightest 20% of the galaxy's flux (M-bar{sub 20}). In this paper, the first of a series, we describe the technical aspects regarding the surface photometry, and present a basic analysis of the global and structural properties of the SINGS galaxies at different wavelengths. The homogeneity in the acquisition, reduction, and analysis of the results presented here makes these data ideal for multiple unanticipated studies on the radial distribution of the properties of stars, dust, and gas in galaxies. Our radial profiles show a wide range of morphologies and multiple components (bulges, exponential disks, inner and outer disk truncations, etc.) that vary not only from galaxy to galaxy but also with wavelength for a given object. In the optical and near-IR, the SINGS galaxies occupy the same regions in the C {sub 42}-A-G-M-bar{sub 20} parameter space as other normal galaxies in previous studies. However, they appear much less centrally concentrated, more asymmetric, and with larger values of G when viewed in the UV (due to star-forming clumps scattered across the disk) and in the mid-IR (due to the emission of polycyclic aromatic hydrocarbons at 8.0 {mu}m and very hot dust at 24 {mu}m). In an accompanying paper by Munoz-Mateos et al., we focus on the radial distribution of dust properties in the SINGS galaxies, providing a detailed analysis of the radial variation of the attenuation, the dust column density, the dust-to-gas ratio, the abundance of PAHs, and the intensity of the heating starlight.

  14. Surface photometry of spiral galaxies. I - Theoretical color variation and surface brightness across spiral arms

    NASA Technical Reports Server (NTRS)

    Yuan, C.; Grosbol, P.

    1981-01-01

    A method for the construction of color variations and surface brightness across a galactic spiral arm, using the concepts and results of the density-wave theory, is developed. The color variation measured by the index Q varies with the ratio of the light of young stars to that of the old stars, the initial mass function, and the pattern speed. The fact that the variation of brightness and color across a spiral arm is relatively smooth and symmetrical and not sharp as in the galactic shock picture is due to the smearing-out effects of star formation inside a cloud in the regions behind the galactic shock, and the tendency of new stars to fall back to small galactocentric distances after their formation because of their lower angular velocity at birth. Both effects arise naturally in the context of the density-wave theory.

  15. Surface photometry of radio loud elliptical galaxies from the B2 sample

    NASA Astrophysics Data System (ADS)

    González-Serrano, J. I.; Carballo, R.

    2000-03-01

    V-band CCD imaging is presented for 72 galaxies from the B2 radio sample (Colla et al. \\cite{colla}; Fanti et al. \\cite{fanti78}), with redshifts up to 0.2 and radio powers P408=1023-1026.5 W Hz-1. According to the morphology on the optical images 57 galaxies are classified as ellipticals, 6 as spirals and 7 as irregular. Surface photometry of the sample of ellipticals was obtained fitting ellipses to the light distribution. The light profile of these galaxies generally follows a de Vaucouleurs law, although in three cases the profiles show large excesses relative to the r1/4 law at large radii. The fitted mu_e and r_e parameters for the de Vaucouleurs galaxies are given in the paper. Three of the ellipticals show a bright nucleus. One of them is a known broad line radio galaxy (B2 1833+32) and the remaining two are Markarian galaxies, classified in the literature as BL Lac objects (B2 1101+38 and B2 1652+39). The radial profiles for ellipticity, position angle, and B_4 term of the Fourier analysis are presented in the paper, and the morphological peculiarities of the ellipticals are described, including the presence of shells, tails, nuclear dust, isophote twisting, off-centering, and boxiness or diskness of the isophotes. Only one of the galaxies in this work is included in the subsample of B2 radio galaxies with well-defined jets (Parma et al. \\cite{parma87}). In this sense the present sample complements the sample of 24 radio galaxies with well-defined radio jets in Parma et al. for which a similar study was presented in González-Serrano et al. (\\cite{gserrano93}). The irregular galaxy B2 0916+33 appears to be misclassified, and we suggest that the right identification of the radio source is a nearby point like object with V=18.45 mag. The spiral galaxy associated with B2 1441+26 is also misclassified. A point-like optical object with V=18.88 mag, located at ~ 36 arcsec from the original identification and coincident with the radio core is the most probable counterpart. Table 4 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html Complete Figure 1 and Figure 2 are only available at http://www.edpsciences.org

  16. Fast Photometry

    NASA Astrophysics Data System (ADS)

    Menke, J.

    2007-05-01

    Fast photometry is measuring changes in brightness in the range of several seconds down to a few milliseconds or faster. Increasingly, asteroid and lunar occultation measurements are carried out using camcorders or video cameras. These can be very inexpensive, and allow event timing to about 0.02 sec. GPS timing signals, good to a microsecond or better, can be combined with video or photometers to allow UTC timing to as good as the sensing device allows. Beyond video cameras that are usually limited to event timing, there is also a role for amateurs to explore true high speed photometry. I will describe use of several inexpensive devices that allow an amateur to conduct fast photometry. I include observing results from this equipment as used in occultation and scintillation studies, and will discuss some of the possible areas of amateur work.

  17. VEGAS: A VST Early-type GAlaxy Survey. I. Presentation, wide-field surface photometry, and substructures in NGC 4472

    NASA Astrophysics Data System (ADS)

    Capaccioli, Massimo; Spavone, Marilena; Grado, Aniello; Iodice, Enrichetta; Limatola, Luca; Napolitano, Nicola R.; Cantiello, Michele; Paolillo, Maurizio; Romanowsky, Aaron J.; Forbes, Duncan A.; Puzia, Thomas H.; Raimondo, Gabriella; Schipani, Pietro

    2015-09-01

    Context. We present the VST Early-type GAlaxy Survey (VEGAS), which is designed to obtain deep multiband photometry in g,r,i, of about one hundred nearby galaxies down to 27.3, 26.8, and 26 mag/arcsec2 respectively, using the ESO facility VST/OmegaCAM. Aims: The goals of the survey are 1) to map the light distribution up to ten effective radii, re; 2) to trace color gradients and surface brightness fluctuation gradients out to a few re for stellar population characterization; and 3) to obtain a full census of the satellite systems (globular clusters and dwarf galaxies) out to 20% of the galaxy virial radius. The external regions of galaxies retain signatures of the formation and evolution mechanisms that shaped them, and the study of nearby objects enables a detailed analysis of their morphology and interaction features. To clarify the complex variety of formation mechanisms of early-type galaxies (ETGs), wide and deep photometry is the primary observational step, which at the moment has been pursued with only a few dedicated programs. The VEGAS survey has been designated to provide these data for a volume-limited sample with exceptional image quality. Methods: In this commissioning photometric paper we illustrate the capabilities of the survey using g- and i-band VST/OmegaCAM images of the nearby galaxy NGC 4472 and of smaller ETGs in the surrounding field. Results: Our surface brightness profiles reach rather faint levels and agree excellently well with previous literature. Genuine new results concern the detection of an intracluster light tail in NGC 4472 and of various substructures at increasing scales. We have also produced extended (g - i) color profiles. Conclusions: The VST/OmegaCAM data that we acquire in the context of the VEGAS survey provide a detailed view of substructures in the optical emission from extended galaxies, which can be as faint as a hundred times below the sky level. Appendices are available in electronic form at http://www.aanda.org

  18. Titan: Preliminary results on surface properties and photometry from VIMS observations of the early flybys

    USGS Publications Warehouse

    Buratti, B.J.; Sotin, C.; Brown, R.H.; Hicks, M.D.; Clark, R.N.; Mosher, J.A.; McCord, T.B.; Jaumann, R.; Baines, K.H.; Nicholson, P.D.; Momary, T.; Simonelli, D.P.; Sicardy, B.

    2006-01-01

    Cassini observations of the surface of Titan offer unprecedented views of its surface through atmospheric windows in the 1-5 ??m region. Images obtained in windows for which the haze opacity is low can be used to derive quantitative photometric parameters such as albedo and albedo distribution, and physical properties such as roughness and particle characteristics. Images from the early Titan flybys, particularly T0, Ta, and T5 have been analyzed to create albedo maps in the 2.01 and 2.73 ??m windows. We find the average normal reflectance at these two wavelengths to be 0.15??0.02 and 0.035??0.003, respectively. Titan's surface is bifurcated into two albedo regimes, particularly at 2.01 ??m. Analysis of these two regimes to understand the physical character of the surface was accomplished with a macroscopic roughness model. We find that the two types of surface have substantially different roughness, with the low-albedo surface exhibiting mean slope angles of ???18??, and the high-albedo terrain having a much more substantial roughness with a mean slope angle of ???34??. A single-scattering phase function approximated by a one-term Henyey-Greenstein equation was also fit to each unit. Titan's surface is back-scattering (g???0.3-0.4), and does not exhibit substantially different backscattering behavior between the two terrains. Our results suggest that two distinct geophysical domains exist on Titan: a bright region cut by deep drainage channels and a relatively smooth surface. The two terrains are covered by a film or a coating of particles perhaps precipitated from the satellite's haze layer and transported by eolian processes. Our results are preliminary: more accurate values for the surface albedo and physical parameters will be derived as more data is gathered by the Cassini spacecraft and as a more complete radiative transfer model is developed from both Cassini orbiter and Huygens Lander measurements. ?? 2006 Elsevier Ltd. All rights reserved.

  19. Investigation of Titan's surface and atmosphere photometry using the VIMS instrument onboard Cassini

    NASA Astrophysics Data System (ADS)

    Cornet, T.; Altobelli, N.; Rodriguez, S.; Maltagliati, L.; Le Mouélic, S.; Sotin, C.; Brown, R. H.; Barnes, J. W.; Buratti, B. J.; Baines, K. H.; Clark, R. N.; Nicholson, P. D.

    2015-10-01

    After 110 targeted flybys of Titan in a decade, the Cassini Visual and Infrared Mapping Spectrometer (VIMS) instrument acquired more than 34,000 hyperspectral cubes pointing at the surface of Titan on the dayside. Due to the strong influence of the absorbing and scattering atmosphere and of the heterogeneous viewing geometry of the flybys, retrieving Titan's surface and atmosphere normal albedo values extracted from the VIMS data remains challenging. In the present work, we aim to determine appropriate photometric functions to describe the light scattering in Titan's atmosphere,which could be used as a basis for empirical corrections or Radiative Transfer (RT) calculations to retrieve normal albedo values for the surface and the atmosphere.

  20. Surface photometry of disk galaxies at 60 and 100 microns - Radial gradients in dust temperature in optically thin disks

    NASA Technical Reports Server (NTRS)

    Bothun, Gregory D.; Rogers, C.

    1992-01-01

    Surface, aperture, and grid photometry are performed at 60 and 100 microns for a sample of 28 nearby, large angular size galaxies. The spatial resolution of the data is 0.5-2.0 kpc, which allows for a coarse investigation of predicted radial gradients in physical dust temperature. A model is derived which predicts a drop of 3 K for every optical scale length, and this model agrees well with the data. In addition, for a subsample of 16 galaxies the radial profile at 60 microns is directly compared with that in the B or I band. The model predicts that optically thick disks should have scale lengths a factor of two smaller at 60 microns compared to B. In the optically thin case, the scale lengths are about equal except for the effect of the gradient in dust temperature. Virtually all of the data support the prediction of the optically thin case. Finally, 10 galaxies in the sample have sufficient angular sizes to allow for a coarse 2D spatial mapping of the 60/100 microns flux ratio. These maps clearly reveal that, when present, small amounts of hot dust dominate the emission at 60 microns and effectively mask the existence of a much larger amount of cold dust.

  1. Surface Photometry of Celestial Sources from a Space Vehicle: Introduction and Observational Procedures*

    PubMed Central

    Roach, Franklin E.; Carroll, Benjamin; Aller, Lawrence H.; Smith, Leroi

    1972-01-01

    Diffuse celestial sources of relatively low surface brightness such as the Milky Way, zodiacal light, and gegenschein (or contre lumière) can be studied most reliably from above the earth's atmosphere with equipment flown in artificial satellites. We review the techniques used and some of the difficulties encountered in day-time observations from satellites by the use of a special photometer and polarimeter flown in the orbiting skylab observatory, OSO-6. PMID:16591970

  2. The photometric functions of Phobos and Deimos. II - Surface photometry of Deimos

    NASA Technical Reports Server (NTRS)

    Noland, M.; Veverka, J.

    1977-01-01

    Mariner 9 television pictures of Deimos are used to study the uniformity of a certain photometric scattering parameter over the surface of the satellite. It is shown that the photometric data considered satisfy the reciprocity principle and that the Hapke-Irvine scattering law is adequate for describing the surface. Phase functions for Deimos are obtained from scans along the photometric equator, and the photometric behavior of the brightest and darkest areas on the satellite's disk is examined. The results indicate that the surface of Deimos is covered uniformly by a dark and texturally complex material whose photometric behavior is well-represented by the Hapke-Irvine law, that the intrinsic phase coefficient of this material is about 0.017 mag/deg over the phase-angle range from 20 to 80 deg, and that slightly brighter material is present near some craters. Since enhanced brightening was not observed at the specular point of the photometric equator in any of the pictures studied, it is concluded that large exposures of solid rock are absent from the Mars-facing side of Deimos.

  3. Near-infrared observations of galaxies in Pisces-Perseus. I. vec H-band surface photometry of 174 spiral

    NASA Astrophysics Data System (ADS)

    Moriondo, G.; Baffa, C.; Casertano, S.; Chincarini, G.; Gavazzi, G.; Giovanardi, C.; Hunt, L. K.; Pierini, D.; Sperandio, M.; Trinchieri, G.

    1999-05-01

    We present near-infrared, H-band (1.65 $() μm), surface photometry of 174 spiral galaxies in the area of the Pisces-Perseus supercluster. The images, acquired with the ARNICA camera mounted on various telescopes, are used to derive radial profiles of surface brightness, ellipticities, and position angles, together with global parameters such as H-band magnitudes and diameters Radial profiles in tabular form and images FITS files are also available upon request from gmorio@arcetri.astro.it.}. The mean relation between H-band isophotal diameter D_{21.5} and the B-band D25 implies a B-H color of the outer disk bluer than 3.5; moreover, D_{21.5}/D25 depends on (global) color and absolute luminosity. The correlations among the various photometric parameters suggest a ratio between isophotal radius D_{21.5}/2 and disk scale length of ~ m3.5 and a mean disk central brightness ~ meq 17.5 H-mag arcsec^{-2}. We confirm the trend of the concentration index C31$ with absolute luminosity and, to a lesser degree, with morphological type. We also assess the influence of non-axisymmetric structures on the radial profiles and on the derived parameters. Based on observations at the TIRGO, NOT, and VATT telescopes. TIRGO (Gornergrat, CH) is operated by CAISMI-CNR, Arcetri, Firenze. NOT (La Palma, Canary Islands) is operated by NOTSA, the Nordic Observatory Scientific Association. VATT (Mt. Graham, Az) is operated by VORG, the Vatican Observatory Research Group Table 3 and Fig. 4 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html.

  4. A radiation-transfer analysis of the effects of dust on the surface photometry of a sample of nearby spiral galaxies

    NASA Astrophysics Data System (ADS)

    Pastrav, Bogdan Adrian; Rushton, Mark T.; Popescu, Cristina C.; Tuffs, Richard J.

    2015-08-01

    Intrinsic scale lengths, inclinations and bulge-to-disk ratios of galaxies are critical inputs for radiation-transfer modelling of the panchromatic (UV/optical-MIR/FIR/submm) broadband spectral energy distribution of spiral galaxies. Although these quantities can be derived from analysis of surface photometry of optical images of targets, the effect of the dust on the measured brightness distributions in the optical must be taken into account if a fully self-consistent analysis incorporating the panchromatic and surface photometry is to be achieved. Here we give results of a careful analysis of surface photometry for a benchmark sample ofwell resolved nearby spiral galaxies. We then show how the results can be used in conjunction with aradiation transfer analysis of the panchromatic output of the same objects and the library of morphological corrections for dust given by Pastrav et al.(2013a,b) to provide self-consistent corrections for the morphological and photometric parameters of the disk and bulge components of the target galaxies.

  5. Surface photometry of brightest cluster galaxies and intracluster stars in ΛCDM

    NASA Astrophysics Data System (ADS)

    Cooper, A. P.; Gao, L.; Guo, Q.; Frenk, C. S.; Jenkins, A.; Springel, V.; White, S. D. M.

    2015-08-01

    We simulate the phase-space distribution of stellar mass in nine massive Λ cold dark matter galaxy clusters by applying the semi-analytic particle tagging method of Cooper et al. to the Phoenix suite of high-resolution N-body simulations (M200 ≈ 7.5-33 × 1014 M⊙). The resulting surface brightness (SB) profiles of brightest cluster galaxies (BCGs) match well to observations. On average, stars formed in galaxies accreted by the BCG account for ≳90 per cent of its total mass (the remainder is formed in situ). In circular BCG-centred apertures, the superposition of multiple debris clouds (each ≳10 per cent of the total BCG mass) from different progenitors can result in an extensive outer diffuse component, qualitatively similar to a `cD envelope'. These clouds typically originate from tidal stripping at z ≲ 1 and comprise both streams and the extended envelopes of other massive galaxies in the cluster. Stars at very low SB contribute a significant fraction of the total cluster stellar mass budget: in the central 1 Mpc2 of a z ˜ 0.15 cluster imaged at SDSS-like resolution, our fiducial model predicts 80-95 per cent of stellar mass below a SB of μV ˜ 26.5 mag arcsec-2 is associated with accreted stars in the envelope of the BCG. The ratio of BCG stellar mass (including this diffuse component) to total cluster stellar mass is ˜30 per cent.

  6. VizieR Online Data Catalog: Surface Photometry of ESO-Uppsala Galaxies (Lauberts+ 1989)

    NASA Astrophysics Data System (ADS)

    Lauberts, A.; Valentijn, E. A.

    2006-04-01

    The 15467 southern galaxies in this catalog were scanned from 407 blue and 407 red original ESO-Schmidt plates using a PDS microdensitometer. The galaxies were selected from the ESO-Uppsala Catalogue (VII/34). The original selection criterion was a minimum visual angular diameter of 1arcmin. The plates were calibrated using a catalog of photo- electric standards of 1700 standard galaxies transformed to a photometric standard system (Cousins) created by the authors. The result is a catalog acquired in a homogeneous fashion for all types of galaxies in various environments. The extracted parameters include radial surface brightness profiles, magnitudes at several isophotal levels, colors, color gradients, effective radius parameters, structural parameters such as axial ratios, position angles, and profile gradients. The full version of the catalog, made of 190 columns, is available as the file "esolv.fit" in FITS table format. The ascii file "esolv1.dat" contains a subset of these columns which includes those parameters listed in the printed book version. Detailed discussion of the catalog creation is given in the published book version (ISBN 3-923524-31-5) (2 data files).

  7. ARCHANGEL: Galaxy Photometry System

    NASA Astrophysics Data System (ADS)

    Schombert, James

    2011-07-01

    ARCHANGEL is a Unix-based package for the surface photometry of galaxies. While oriented for large angular size systems (i.e. many pixels), its tools can be applied to any imaging data of any size. The package core contains routines to perform the following critical galaxy photometry functions: sky determinationframe cleaningellipse fittingprofile fittingtotal and isophotal magnitudes The goal of the package is to provide an automated, assembly-line type of reduction system for galaxy photometry of space-based or ground-based imaging data. The procedures outlined in the documentation are flux independent, thus, these routines can be used for non-optical data as well as typical imaging datasets. ARCHANGEL has been tested on several current OS's (RedHat Linux, Ubuntu Linux, Solaris, Mac OS X). A tarball for installation is available at the download page. The main routines are Python and FORTRAN based, therefore, a current installation of Python and a FORTRAN compiler are required. The ARCHANGEL package also contains Python hooks to the PGPLOT package, an XML processor and network tools which automatically link to data archives (i.e. NED, HST, 2MASS, etc) to download images in a non-interactive manner.

  8. How surface damage removal affects fatigue life

    NASA Technical Reports Server (NTRS)

    Jeelani, S.; Scott, M. A.

    1988-01-01

    The effect of the removal of work hardened surface layers from specimens of 2024-T4 aluminum alloy and AISI-4130 steel on their fatigue lives has been investigated. Specimens were fatigued at selected stress levels for a given number of cycles, and the surface layer was removed followed by subsequent fatigue cycling. Results confirm that when a material is subjected to fatigue loading, damage accumulates in the surface layers in the form of work hardening. Removal of the surface layer brings the specimen back to its pre-fatigued condition.

  9. Produce Surface Characteristics Affect Product Quality and Safety

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The surface characteristics of fresh-cut fruits and vegetables vary largely among produce types, maturities and processing procedure. Studies have shown that the surface topography of produce significantly affected adherence, attachment, and biofilm formation of bacteria, as well as their removal a...

  10. GHASP: an Hα kinematic survey of spiral galaxies - X. Surface photometry, decompositions and the Tully-Fisher relation in the Rc band

    NASA Astrophysics Data System (ADS)

    Barbosa, C. E.; Mendes de Oliveira, C.; Amram, P.; Ferrari, F.; Russeil, D.; Epinat, B.; Perret, V.; Adami, C.; Marcelin, M.

    2015-11-01

    We present Rc-band surface photometry for 170 of the 203 galaxies in GHASP, the Gassendi H-alpha survey of spirals, a sample of late-type galaxies for which high-resolution Fabry-Perot Hα maps have previously been obtained. Our data set is constructed using new Rc-band observations taken at the Observatoire de Haute-Provence, supplemented with Sloan Digital Sky Survey archival data, obtained with the purpose of deriving homogeneous photometric profiles and parameters. Our results include Rc-band surface brightness profiles for 170 galaxies and ugriz profiles for 108 of these objects. We catalogue several parameters of general interest for further reference, such as total magnitude, effective radius and isophotal parameters (magnitude, position angle, ellipticity and inclination). We also perform a structural decomposition of the surface brightness profiles using a multi-component method to separate discs from bulges and bars, and to observe the main scaling relations involving luminosities, sizes and maximum velocities. We determine the Rc-band Tully-Fisher relation using maximum velocities derived solely from Hα rotation curves for a sample of 80 galaxies, resulting in a slope of -8.1 ± 0.5, zero-point of -3.0 ± 1.0 and an estimated intrinsic scatter of 0.28 ± 0.07. We note that, unlike the Tully-Fisher relation in the near-infrared derived for the same sample, no change in the slope of the relation is seen at the low-mass end (for galaxies with Vmax < 125 km s-1). We suggest that this different behaviour of the Tully-Fisher relation (with the optical relation being described by a single power law while the near-infrared has two), may be caused by differences in the stellar mass-to-light ratio for galaxies with Vmax < 125 km s-1.

  11. Andromeda (M31) optical and infrared disk survey. I. Insights in wide-field near-IR surface photometry

    SciTech Connect

    Sick, Jonathan; Courteau, Stéphane; Cuillandre, Jean-Charles; McDonald, Michael; De Jong, Roelof; Tully, R. Brent

    2014-05-01

    We present wide-field near-infrared J and K{sub s} images of the Andromeda Galaxy (M31) taken with WIRCam at the Canada-France-Hawaii Telescope as part of the Andromeda Optical and Infrared Disk Survey. This data set allows simultaneous observations of resolved stars and near-infrared (NIR) surface brightness across M31's entire bulge and disk (within R = 22 kpc), permitting a direct test of the stellar composition of near-infrared light in a nearby galaxy. Here we develop NIR observation and reduction methods to recover a uniform surface brightness map across the 3° × 1° disk of M31 with 27 WIRCam fields. Two sky-target nodding strategies are tested, and we find that strictly minimizing sky sampling latency cannot improve background subtraction accuracy to better than 2% of the background level due to spatio-temporal variations in the NIR skyglow. We fully describe our WIRCam reduction pipeline and advocate using flats built from night-sky images over a single night, rather than dome flats that do not capture the WIRCam illumination field. Contamination from scattered light and thermal background in sky flats has a negligible effect on the surface brightness shape compared to the stochastic differences in background shape between sky and galaxy disk fields, which are ∼0.3% of the background level. The most dramatic calibration step is the introduction of scalar sky offsets to each image that optimizes surface brightness continuity. Sky offsets reduce the mean surface brightness difference between observation blocks from 1% to <0.1% of the background level, though the absolute background level remains statistically uncertain to 0.15% of the background level. We present our WIRCam reduction pipeline and performance analysis to give specific recommendations for the improvement of NIR wide-field imaging methods.

  12. How surface roughness affects chemical transfer from soil to surface runoff?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil surface roughness affects transport processes, e.g., runoff generation, infiltration, sediment detachment, etc., occurring on the surface. Nevertheless, how soil roughness affects chemical transport is less known. In this study, we partitioned roughness elements into mounds which diverge water ...

  13. Activities affecting surface water resources: A general overview

    SciTech Connect

    Not Available

    1990-01-01

    In November 1987, P.E.I. signed a federal/provincial work-sharing arrangement on water resource management focusing on groundwater pollution, surface water degradation and estuarine eutrophication. The surface water program was designed to identify current surface water uses and users within 12 major watersheds across the Island containing 26 individual rivers, as well as problems arising due to practices that degrade the quality of surface water and restricts its value to other user groups. This report presents a general overview of the program, covering the general characteristics of the Island; operations in agriculture, fish and wildlife, forestry, recreation, fisheries, and industry; alterations of natural features of waterways; wetlands; additional watershed activities such as hydrometric stations and subdivision development; and activities affecting surface water resources such as sedimentation sources, pollution point sources and instream obstructions.

  14. QDPHOT: Quick & Dirty PHOTometry

    NASA Astrophysics Data System (ADS)

    Mighell, Kenneth

    2016-01-01

    QDPHOT is a fast CCD stellar photometry task which quickly produces CCD stellar photometry from two CCD images of a star field. It was designed to be a data mining tool for finding high-quality stellar observations in the data archives of the National Virtual Observatory. QDPHOT typically takes just a few seconds to analyze two Hubble Space Telescope WFPC2 observations of Local Group star clusters. It is also suitable for real-time data-quality analysis of CCD observations; on-the-fly instrumental color-magnitude diagrams can be produced at the telescope console during the few seconds between CCD readouts.

  15. Detailed photometry of Comet Crommelin (1983 n)

    NASA Astrophysics Data System (ADS)

    Sizonenko, Iu. V.

    1986-04-01

    A computer-aided procedure used to obtain detailed photometry of Comet Crommelin (1983 n) is described. Determinations are made of the integral magnitude of the comet and of the magnitude of the bright nucleus. Analytical expressions are obtained which relate the surface brightness of the comet to the distance from the photometric center along selected directions.

  16. The SL2S Galaxy-scale Lens Sample. III. Lens Models, Surface Photometry, and Stellar Masses for the Final Sample

    NASA Astrophysics Data System (ADS)

    Sonnenfeld, Alessandro; Gavazzi, Raphaël; Suyu, Sherry H.; Treu, Tommaso; Marshall, Philip J.

    2013-11-01

    We present Hubble Space Telescope (HST) imaging data and Canada-France-Hawaii Telescope (CFHT) near-infrared ground-based images for the final sample of 56 candidate galaxy-scale lenses uncovered in the CFHT Legacy Survey as part of the Strong Lensing in the Legacy Survey project. The new images are used to perform lens modeling, measure surface photometry, and estimate stellar masses of the deflector early-type galaxies (ETGs). Lens modeling is performed on the HST images (or CFHT when HST is not available) by fitting the spatially extended light distribution of the lensed features assuming a singular isothermal ellipsoid mass profile and by reconstructing the intrinsic source light distribution on a pixelized grid. Based on the analysis of systematic uncertainties and comparison with inference based on different methods, we estimate that our Einstein radii are accurate to ~3%. HST imaging provides a much higher success rate in confirming gravitational lenses and measuring their Einstein radii than CFHT imaging does. Lens modeling with ground-based images, however, when successful, yields Einstein radius measurements that are competitive with space-based images. Information from the lens models is used together with spectroscopic information from companion Paper IV to classify the systems, resulting in a final sample of 39 confirmed (grade A) lenses and 17 promising candidates (grade B,C). This represents an increase of half an order of magnitude in sample size with respect to the sample of confirmed lenses studied in Papers I and II. The Einstein radii of the confirmed lenses in our sample span the range 5-15 kpc and are typically larger than those of other surveys, probing the mass in regions where the dark matter contribution is more important. Stellar masses are in the range 1011-1012 M ⊙, covering the range of massive ETGs. The redshifts of the main deflector span a range 0.3 <= zd <= 0.8, which nicely complements low-redshift samples like the Sloan Lens ACS survey and thus provides an excellent sample for the study of the cosmic evolution of the mass distribution of ETGs over the second half of the history of the universe.

  17. THE SL2S GALAXY-SCALE LENS SAMPLE. III. LENS MODELS, SURFACE PHOTOMETRY, AND STELLAR MASSES FOR THE FINAL SAMPLE

    SciTech Connect

    Sonnenfeld, Alessandro; Suyu, Sherry H.; Treu, Tommaso; Gavazzi, Raphaël; Marshall, Philip J.

    2013-11-10

    We present Hubble Space Telescope (HST) imaging data and Canada-France-Hawaii Telescope (CFHT) near-infrared ground-based images for the final sample of 56 candidate galaxy-scale lenses uncovered in the CFHT Legacy Survey as part of the Strong Lensing in the Legacy Survey project. The new images are used to perform lens modeling, measure surface photometry, and estimate stellar masses of the deflector early-type galaxies (ETGs). Lens modeling is performed on the HST images (or CFHT when HST is not available) by fitting the spatially extended light distribution of the lensed features assuming a singular isothermal ellipsoid mass profile and by reconstructing the intrinsic source light distribution on a pixelized grid. Based on the analysis of systematic uncertainties and comparison with inference based on different methods, we estimate that our Einstein radii are accurate to ∼3%. HST imaging provides a much higher success rate in confirming gravitational lenses and measuring their Einstein radii than CFHT imaging does. Lens modeling with ground-based images, however, when successful, yields Einstein radius measurements that are competitive with space-based images. Information from the lens models is used together with spectroscopic information from companion Paper IV to classify the systems, resulting in a final sample of 39 confirmed (grade A) lenses and 17 promising candidates (grade B,C). This represents an increase of half an order of magnitude in sample size with respect to the sample of confirmed lenses studied in Papers I and II. The Einstein radii of the confirmed lenses in our sample span the range 5-15 kpc and are typically larger than those of other surveys, probing the mass in regions where the dark matter contribution is more important. Stellar masses are in the range 10{sup 11}-10{sup 12} M{sub ☉}, covering the range of massive ETGs. The redshifts of the main deflector span a range 0.3 ≤ z{sub d} ≤ 0.8, which nicely complements low-redshift samples like the Sloan Lens ACS survey and thus provides an excellent sample for the study of the cosmic evolution of the mass distribution of ETGs over the second half of the history of the universe.

  18. Third Workshop on Photometry

    NASA Technical Reports Server (NTRS)

    Borucki, William J. (Editor); Lasher, Lawrence E. (Editor)

    2001-01-01

    The discoveries of extrasolar planets by Wolszczan, Mayor and Queloz, Butler et al., and others have stimulated a widespread effort to obtain a body of data sufficient to understand their occurrence and characteristics. Doppler velocity techniques have found dozens of extrasolar planets with masses similar to that of Jupiter. Approximately ten percent of the stars that show planets with orbital periods of a few days to a week are expected to show transits. With the mass obtained from Doppler velocity measurements and the size from transit photometry, the densities of the planets can be determined. Theoretical models of the structure of "hot Jupiters" (i.e., those planets within a tenth of an astronomical unit (AU) of the parent star) indicate that these planets should be substantially larger in size and lower in density than Jupiter. Thus the combination of transit and Doppler velocity measurements provide a critical test of the theories of planetary structure. Furthermore, because photometry can be done with small-aperture telescopes rather than requiring the use of much larger telescopes, transit photometry should also reduce the cost of discovering extrasolar planets.

  19. BV photometry of UX ARIETIS

    NASA Astrophysics Data System (ADS)

    Mohin, S.; Raveendran, A. V.

    1989-03-01

    Differential BV photometry of UX Ari obtained on 58 nights during 1984-1985, 1985-1986, 1986-1987, and 1987-1988 observing season is presented. It is found that (B-V) is phase dependent, with the system being reddest at the light maximum. This is interpreted as being due to the variable fractional contribution by the G5 V component to the total light at shorter wavelengths. An analysis of the available data indicates that, at larger amplitudes of the photometric wave, the brightness at maximum increases and that at minimum decreases, and both converge to DeltaV of about 1.0 mag at very low amplitudes. It implies that the low wave amplitudes are essentially due to more homogeneity in the surface distribution of spots rather than to low levels of spot activity. The variation in wave amplitude is found to be near-sinusoidal with a period around 13-14 years.

  20. The 2060 Chiron: CCD photometry

    NASA Technical Reports Server (NTRS)

    Bus, Schelte J.; Bowell, Edward; Harris, Alan W.

    1987-01-01

    R-band CCD photometry of 2060 was carried out on nine nights in Nov. and Dec. 1986. The rotation period is 5.9181 + or - 0.0003 hr and the peak to peak lightcurve amplitude is 0.088 + or - 0.0003 mag. Photometric parameters are H sub R = 6.24 + or - 0.02 mag and G sub R = + or - 0.15, though formal errors may not be realistic. The lightcurve has two pairs of extrema, but its asymmetry, as evidenced by the presence of significant odd Fourier harmonics, suggests macroscopic surface irregularities and/or the presence of some large scale albedo variegation. The observational rms residual is + or - 0.015 mag. On time scales from minutes to days there is no evidence for nonperiodic (cometary) brightness changes at the level of a few millimagnitudes.

  1. New BVIc Photometry of the Pleiades

    NASA Astrophysics Data System (ADS)

    Kamai, Brittany; Vrba, F. J.; Stauffer, J. R.; Stassun, K. G.

    2010-01-01

    We have obtained new BVIc photometry for 332 members of the Pleiades open cluster. This more than doubles the amount of Johnson/Cousins photometric data for the low-mass stars of this cluster. Our target stars are proper motion members fainter than V = 9 for which there is no published photoelectric photometry in the Cousins system (or where only V or Ic were previously observed). We identify that 3% of the stars we observed are probable non-members, based on their significant displacement either above or below the Pleiades locus in color-magnitude diagrams. We use the new photometry to redefine the single-star main sequence isochrone for the Pleiades. We compare the new Pleiades main-sequence to accurate published photometry for low mass stars in two other well-studied, older nearby open clusters - Praesepe and the Hyades. The new observations allow us to provide improved measures of how youth (primarily via rapid rotation) affects the SEDs of young, low mass stars, as previously discussed in Stauffer et al. (2003).

  2. Do surface processes and/or the presence of an initial surface topography affect(s) the fold linkage?

    NASA Astrophysics Data System (ADS)

    Collignon, Marine; Fernandez, Naiara; Kaus, Boris J. P.

    2014-05-01

    Landscape geomorphology provides an indirect observation of the tectonic activity. Surface processes and tectonics interact one with another to create a wide variety of landscape. Geomorphic features such as wind gaps can record the amplification and lateral propagation of embryonic fold segments. Depending of their relative initial spacing, those growing fold segments can link and form long train folds. This mechanism has been suggested for the Zagros Folded Belt, where the axial lengths of folds can reach more than 100 km. Previous studies have focused on fold linkage or on the response of the drainage network to tectonic forcing. Using seeds in their setup to prescribe the fold orientation, Grasemann and Schmalholz (2012) numerically investigated the distance between two isolated laterally propagating folds to explain the different modes of linkage. However, the effects of surface processes on the fold development have not been considered. Our recent multilayer folding experiments, in which an initial random perturbation was prescribed, have shown that under efficient drainage network conditions, or when a non-zero initial topography was applied to the model, the type of fold linkage could be modified. In this study we systematically investigate the effects of surface processes on the mode of linkage and how the distance between two isolated growing perturbations, required for linkage, is affected. In order to address this question, we use the 3D thermo-mechanical code LaMEM, which has been coupled to a finite-element based landscape evolution model (both erosion and sedimentation). The landscape evolution model uses a non-linear diffusion formulation (Simpson and Schlunegger, 2003) taking into account both hillslopes and channel processes. Graseman, B., and Schmalholz, S. M., 2012, Lateral fold growth and fold linkage: Geology, v. 40. Simpson, G., and Schlunegger, F., 2003, Topographic evolution and morphology of surfaces evolving in repsonse to coupled fluvial and hillslope sediment transport: Journal of geophysical research, v. 108, p. 16p.

  3. THE IMPACT OF CONTAMINATED RR LYRAE/GLOBULAR CLUSTER PHOTOMETRY ON THE DISTANCE SCALE

    SciTech Connect

    Majaess, D.; Turner, D.; Lane, D.; Gieren, W.

    2012-06-10

    RR Lyrae variables and the stellar constituents of globular clusters are employed to establish the cosmic distance scale and age of the universe. However, photometry for RR Lyrae variables in the globular clusters M3, M15, M54, M92, NGC 2419, and NGC 6441 exhibit a dependence on the clustercentric distance. For example, variables and stars positioned near the crowded high-surface brightness cores of the clusters may suffer from photometric contamination, which invariably affects a suite of inferred parameters (e.g., distance, color excess, absolute magnitude, etc.). The impetus for this study is to mitigate the propagation of systematic uncertainties by increasing awareness of the pernicious impact of contaminated and radial-dependent photometry.

  4. k2photometry: Read, reduce and detrend K2 photometry

    NASA Astrophysics Data System (ADS)

    Van Eylen, Vincent; Nowak, Grzegorz; Albrecht, Simon; Palle, Enric; Ribas, Ignasi; Bruntt, Hans; Perger, Manuel; Gandolfi, Davide; Hirano, Teriyuki; Sanchis-Ojeda, Roberto; Kiilerich, Amanda; Arranz, Jorge P.; Badenas, Mariona; Dai, Fei; Deeg, Hans J.; Guenther, Eike W.; Montanes-Rodriguez, Pilar; Narita, Norio; Rogers, Leslie A.; Bejar, Victor J. S.; Shrotriya, Tushar S.; Winn, Joshua N.; Sebastian, Daniel

    2016-02-01

    k2photometry reads, reduces and detrends K2 photometry and searches for transiting planets. MAST database pixel files are used as input; the output includes raw lightcurves, detrended lightcurves and a transit search can be performed as well. Stellar variability is not typically well-preserved but parameters can be tweaked to change that. The BLS algorithm used to detect periodic events is a Python implementation by Ruth Angus and Dan Foreman-Mackey (https://github.com/dfm/python-bls).

  5. Photometry from space

    NASA Technical Reports Server (NTRS)

    Nelson, M. J.; Bless, R. C.; Percival, J. W.; White, R. L.

    1992-01-01

    A brief description of the High Speed Photometer (HSP) of the Hubble Space Telescope is given, in particular the HSP light path, detectors, entrance apertures, and filters. The status of HSP testing to date is reported, and problems encountered with the bright earth and the telescope pointing system are described. The calibration effort for the HSP is well under way. Results of internal (instrument coordinate) aperture locations good to 0.05 arcsec and external (telescope coordinate) locations good to 0.02 arcsec are shown. The effects of spacecraft pointing and jitter on HSP photometry are detailed, and a preliminary measurement of spacecraft jitter with HSP is shown. The aperture calibration effort is verified by accurate pointing of a star to different HSP 1.0 arcsec entrance apertures, and photometric performance of the instrument is shown to be accurate to the 2 percent photon noise of the observations. Future science verification and guaranteed observing time programs are listed. Suggestions are made for future space-based photometers.

  6. How Direction of Illumination Affects Visually Perceived Surface Roughness

    PubMed Central

    Ho, Yun-Xian; Landy, Michael S.; Maloney, Laurence T.

    2009-01-01

    We examined visual estimation of surface roughness using random computer-generated three-dimensional (3D) surfaces rendered under a mixture of diffuse lighting and a punctate source. The angle between the tangent to the plane containing the surface texture and the direction to the punctate source was varied from 50 to 70 degrees across lighting conditions. Observers were presented with pairs of surfaces under different lighting conditions and indicated which 3D surface appeared rougher. Surfaces were viewed either in isolation or in scenes with added objects whose shading, cast shadows and specular highlights provided information about the spatial distribution of illumination. All observers perceived surfaces to be markedly rougher with decreasing illuminant angle. Performance in scenes with added objects was no closer to constant than that in scenes without added objects. We identified four novel cues that are valid cues to roughness under any single lighting condition but that are not invariant under changes in lighting condition. We modeled observers’ deviations from roughness constancy as a weighted linear combination of these “pseudo-cues” and found that they account for a substantial amount of observers’ systematic deviations from roughness constancy with changes in lighting condition. PMID:16881794

  7. Photometry of umbral dots

    NASA Astrophysics Data System (ADS)

    Sobotka, M.; Hanslmeier, A.

    2005-10-01

    Until now, the size of umbral dots has been considered to be below the resolution limit of large solar telescopes. We analyze observations of two sunspots and two pores, acquired in September 2003 with the new 1-m Swedish Solar Telescope, La Palma. White-light images with a resolution better than 0.15 arcsec were taken simultaneously in blue (451 nm) and red (602 nm) wavelength bands. They were corrected for scattered light and restored for the instrumental profile of the telescope. Intensities, diameters and positions of umbral dots were measured in aligned pairs of images in the blue and red wavelength band. We find that observed intensities of umbral dots are correlated with local intensities of umbral background. On average, UDs are by about 1000 K hotter than the coolest area in the umbra and by 500-1000 K cooler than the undisturbed photosphere. Individual UDs may reach or exceed the average photospheric brightness and temperature. Histograms of observed diameters peak at 0.23 arcsec (170 km). This indicates that the majority of umbral dots are spatially resolved with the 1-m telescope. The mean nearest-neighbour distance between umbral dots is 0.4 arcsec and their average observed filling factor is 9%. The method of two-colour photometry is discussed and applied to obtain average "true" intensities and diameters. About 50% of umbral dots are brighter than the quiet photosphere and the average "true" diameter of umbral dots is 100 km. However, the latter results might be influenced by systematic errors of the method.

  8. Plant surface wax affects parasitoid's response to host footprints.

    PubMed

    Rostás, Michael; Ruf, Daniel; Zabka, Vanessa; Hildebrandt, Ulrich

    2008-10-01

    The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants (cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones. PMID:18548222

  9. Plant surface wax affects parasitoid's response to host footprints

    NASA Astrophysics Data System (ADS)

    Rostás, Michael; Ruf, Daniel; Zabka, Vanessa; Hildebrandt, Ulrich

    2008-10-01

    The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants ( cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones.

  10. Free-surface stability criterion as affected by velocity distribution

    USGS Publications Warehouse

    Cheng-Lung, Chen

    1995-01-01

    This paper examines how the velocity distribution of flow in open channels affects the kinematic and dynamic wave velocities, from which the various forms of the Vedernikov number V can be formulated. When V >1, disturbances created in open-channel flow will amplify in the form of roll waves; when V <1, some (though not all) disturbances will attenuate. A study of the Vedernikov stability criterion reveals that it can be readily deduced within the framework of the kinematic and dynamic wave theories by comparing the kinematic wave velocity to the corresponding dynamic wave velocity. -from Author

  11. Detection by Transit Photometry

    NASA Technical Reports Server (NTRS)

    Borucki, William J.; Koch, David G.; Jenkins, Jon M.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    A periodic sequence of planetary transits provides a valid detection of an orbiting planet and provides the relative size of the planet and its orbital period. Ancillary measurements of the stellar spectrum and the variations of the star's radial velocity or position combined with stellar models allow the absolute size of the planet and its mass to be obtained. The results of this approach have already shown that the planet orbiting HD209458 has only 70% of the mass of Jupiter, but is nearly 50% larger in radius. Based on models of planetary structure, these results imply that the planet must have spent most of its lifetime so close to the star that it has not been able to cool and contract as have the giant planets in our Solar System. Thus its density is much less than Jupiter and Saturn and is actually less than that of water; i.e., about 0.4 gr/cu cm. If more sensitive measurements of the light curve of stars with closely orbiting planets can be made that provide the varying amplitude of the light reflected by the planet at various phases in its orbit, then characteristics of the planetary atmosphere can be obtained. Potentially, these data can identify major molecular species present in the atmosphere and tell us if clouds are present and yield the phase function of the aerosols. Although such detail cannot be obtained for Earth-size planets because their signal amplitudes are too small, it is possible to get data critical to the determination of the structure of extrasolar planetary systems. In particular, the size distributions and their orbital distributions can be measured by the transit photometry missions now in development. The COROT mission should be able to find large terrestrial planets in short-period orbits while the more ambitious Kepler and Eddington missions should be able to detect planets even smaller than the Earth and at orbital distances that place them in the habitable zone of their stars.

  12. Lunar Mare Photometry from SMART-1/AMIE Data

    NASA Astrophysics Data System (ADS)

    Wilkman, Olli; Muinonen, K.; Parviainen, H.; Näränen, J.; Videen, G.; Josset, J.; Beauvivre, S.; SMART-1 AMIE Team

    2012-10-01

    The SMART-1 spacecraft pioneered European lunar exploration with its orbiting mission in 2004-2006. Among its instruments was the optical/near-infrared camera AMIE which mapped the lunar surface with a resolution between 40 to 200 metres per pixel. We have taken a sample of over eight hundred AMIE frames, representing most of the mare regions of the near side. We extracted multi-angular photometry from the images by sampling the brightness of the surface and estimating the local observational geometry (the directions to the camera and the Sun compared to the surface normal). We assume that the photometric properties of mare surfaces are similar in all the regions studied and consider the entire data set as representing "average" mare properties. Mare surfaces were chosen because they are smooth, making the estimation of the observational geometry simple, and also because they are dark, justifying the use of the Lommel-Seeliger scattering law. Using a numerical ray-tracing code with a simulated regolith medium we compute the effect of mutual shadowing of surface particles. This simulation considers the full observational geometry and includes azimuthal shadowings effects. The contribution of shadowing can then be removed from the data, resulting in a phase function for the lunar mare surfaces. In all cases, the reduced phase function shows a significant opposition effect, indicating that the lunar opposition effect is not explainable through shadowing effects only. Physical properties of the surface such as porosity and surface roughness affect the shadowing function. By varying these properties in the ray-tracing simulation, some information of the corresponding properties of the lunar surface may be gained. Research supported, in part, by the Academy of Finland (contract 127461) and by the NASA Lunar Advanced Science and Exploration Research Program (contract NNX11AB25G).

  13. The RINGS Survey: Optical Broadband Photometry

    NASA Astrophysics Data System (ADS)

    Kuzio de Naray, Rachel; Mitchell, Carl; Spekkens, Kristine; Sellwood, Jerry; Williams, Ted

    2016-01-01

    We have targeted a sample of 19 nearby spiral galaxies, the RSS Imaging and Spectroscopy Nearby Galaxy Survey (RINGS), for detailed study of their mass distributions. We have obtained Fabry-Perot Halpha velocity fields using the Southern African Large Telescope (SALT), 21-cm HI observations using the Very Large Array (VLA), and optical broadband BVRI photometry using the CTIO 0.9m and KPNO 2.1m telescopes. We present the results of the photometric component of the survey including multicolor images, surface brightness profiles, and DiskFit structural models.

  14. PHOTOM: Photometry of digitized images

    NASA Astrophysics Data System (ADS)

    Eaton, Nicholas; Draper, Peter W.; Allan, Alasdair; Naylor, Tim; Mukai, Koji; Currie, Malcolm J.; McCaughrean, Mark

    2014-05-01

    PHOTOM performs photometry of digitized images. It has two basic modes of operation: using an interactive display to specify the positions for the measurements, or obtaining those positions from a file. In both modes of operation PHOTOM performs photometry using either the traditional aperture method or via optimal extraction. When using the traditional aperture extraction method the target aperture can be circular or elliptical and its size and shape can be varied interactively on the display, or by entering values from the keyboard. Both methods allow the background sky level to be either sampled interactively by the manual positioning of an aperture, or automatically from an annulus surrounding the target object. PHOTOM is the photometry backend for the GAIA tool (ascl:1403.024) and is part of the Starlink software collection (ascl:1110.012).

  15. Second Workshop on Improvements to Photometry

    NASA Technical Reports Server (NTRS)

    Borucki, William J. (Editor)

    1988-01-01

    The papers in these proceedings show that a major effort is under way to improve all aspects of photometry. Astronomical multichannel photometry, photodiodes, analog-to-digital converters, data reduction techniques, interference filters and optical fibers are discussed.

  16. Multicolor photoelectric photometry of Neptune.

    NASA Technical Reports Server (NTRS)

    Appleby, J. F.

    1973-01-01

    Mean opposition magnitudes at unit distance and geometric albedos obtained as functions of wavelength from multicolor photoelectric photometry observations of Neptune performed in southern France and South Africa are presented. The measurements were made in the standard UBV bands and in seven narrow bands isolated by interference filters between 0.314 and 0.627 microns.

  17. Time Series Photometry of the Youngest Stars - MIPS24 Photometry for IC1396A

    NASA Astrophysics Data System (ADS)

    Stauffer, John; Carey, Sean; Hartmann, Lee; Hillenbrand, Lynne; Morales, Maria; Rebull, Luisa; Werner, Michael

    2008-08-01

    We have recently obtained IRAC time-series photometry of the embedded, very young cluster of young stellar objects (YSOs) in the Elephant's Trunk Nebula (a.k.a. IC1396A). About 20% of the YSOs, including about half of the Class I stars, showed relatively large amplitude (> 0.1 mag) variability with characteristic timescales of 4 to 15 days, and with very little difference in light curve shape and amplitude between 3.6 and 8 microns. The most plausible physical model for these variations is that we are seeing these stars primarilyin scattered light all the way out to 8 microns, and that the sources of the variability are hot spots (from accretion flows) on the surfaces of these stars. In order to place further constraints on models for these stars, we propose to obtain MIPS24 photometric observations of the 5'x5' "head" of the IC1396A star-forming globule at sixteen epochs, about twice per day, during a single MIPS campaign. We will also obtain a small amount of new IRAC time-series photometry in an adjacent campaign in order to place the MIPS photometry in better context with the existing IRAC light curves obtained in February 2008. The entire set of observations requires 3.6 hours of observing time.

  18. Photometry of Phoebe

    NASA Technical Reports Server (NTRS)

    Kruse, S.; Klavetter, J. J.; Dunham, E. W.

    1986-01-01

    The nonsynchronous rotational period and light curve for Phoebe are analyzed. The variations in CCD chip pixel response, the intensity of the images, the sky background level, and the atmospheric effects and color response of the detector are examined. Consideration is also given to brightness variations and the solar phase function at small phase angles (0.2-1.2 deg) of the light curve. The Phoebe surface is compared with asteroid surfaces by fitting the data to a linear phase function. It is determined that the Phoebe's sidereal rotational period is refined to 9.282 + or - 0.015 hr, the light curve in V filter exhibits 20 percent brightness variations with weaker higher-order harmonics, and the solar phase coefficient at angles less than 1.2 deg is 0.180 + or 0.035 mag/deg. The Phoebe data at small phase angles correlated well with a phase function for C-type asteroids.

  19. Voyager photometry of Io

    SciTech Connect

    Simonelli, D.P.

    1987-01-01

    Detailed disk-integrated and disk-resolved photometric studies of the Jovian moon Io were carried out using Voyager images. Disk-integrated properties derived from the Voyager data, such as phase curves, rotation curves, geometric albedos, phase integrals, and the Bond albedo, are generally consistent with earth-based estimates. Near-opposition limb-darkening behavior, as parameterized by the Minnaert photometric function, has been accurately measured for regions on the surface of Io in three distinct color classes: Bright (white), Average (orange), and Polar (brown). The limb-darkening results allow derivation of accurate near-opposition disk-resolved phase curves, revealing substantial differences in opposition surge among the color classes. Modeling of the phase curves using the Hapke photometric function supports the contention that the uppermost layer of the Ionian surface is on average extremely porous, and suggests that this layer is substantially more porous in Average and Polar areas than in the Bright regions, a difference consistent with models of Io's surface layer. Combination of limb-darkening and phase information leads to determination of accurate normal reflectance spectra for the color classes; careful comparison with laboratory data supports earlier claims that the spectra of Ionian materials can be explained by mixtures of sulfur and SO/sub 2/ frost, although this is not a unique diagnostic identification.

  20. Photometry of compact galaxies.

    NASA Technical Reports Server (NTRS)

    Shen, B. S. P.; Usher, P. D.; Barrett, J. W.

    1972-01-01

    Photometric histories of the N galaxies 3C 390.3 and PKS 0521-36. Four other compact galaxies, Markarian 9, I Zw 92, 2 Zw 136, and III Zw 77 showed no evidence of variability. The photometric histories were obtained from an exhaustive study of those plates of the Harvard collection taken with large aperture cameras. The images of all galaxies reported were indistinguishable from stars due to the camera f-ratios and low surface brightness of the outlying nebulosities of the galaxies. Standard techniques for the study of variable stars are therefore applicable.

  1. Friction, Wear, and Surface Damage of Metals as Affected by Solid Surface Films

    NASA Technical Reports Server (NTRS)

    Bisson, Edmond E; Johnson, Robert L; Swikert, Max A; Godfrey, Douglas

    1956-01-01

    As predicted by friction theory, experiments showed that friction and surface damage of metals can be reduced by solid surface films. The ability of materials to form surface films that prevent welding was a very important factor in wear of dry and boundary lubricated surfaces. Films of graphitic carbon on cast irons, nio on nickel alloys, and feo and fe sub 3 o sub 4 on ferrous materials were found to be beneficial. Abrasive films such as fe sub 2 o sub 3 or moo sub 3 were definitely detrimental. It appears that the importance of oxide films to friction and wear processes has not been fully appreciated.

  2. Characterisation of the Gaia photometry

    NASA Astrophysics Data System (ADS)

    Carrasco, J. M.; Jordi, C.; Fabricius, C.; Voss, H.; Weiler, M.

    2014-07-01

    Our team at the University of Barcelona has contributed since the early phases of the mission to the definition, evaluation and calibration modelling of the Gaia photometry. To maximise the Gaia scientific exploitation, we have frequently shared many different tools and data with the astronomical community. Among this information we have defined several relationships among colours involving Gaia magnitudes and colours from other commonly used photometric systems (Johnson-Cousins, SDSS, Hipparcos, Tycho and 2MASS) for several types of stars (including white dwarfs). These relationships can be used for planning scientific exploitation of Gaia data, performing simulations of the Gaia-like sky, planning ground-based complementary observations and for building catalogues with auxiliary validation data. During the commissioning phase our team (as part of the Payload Experts group) has been intensively checking the first photometric data to analyse the health and properties of the real instrument. These preliminary analyses allowed us to monitor the throughput variations with time, assess the spectral resolution and re-evaluate the performances of the end-of-mission photometry. The Payload Experts group activities continue beyond the commissioning phase aiming to optimize the operations onboard for maximizing the scientific return. Some example of first spectra and photometry are shown.

  3. Multicolour Optical Photometry of Active Geostationary Satellites

    NASA Astrophysics Data System (ADS)

    Jolley, A.; Wade, G.; Bedard, D.

    Although broadband photometry has been used to infer information about artificial satellites since soon after the launch of Sputnik 1, the development of photometric techniques for non-resolved space object identification or characterisation has been hampered by the large number of variables involved. Many individual studies, and some long ongoing experiments, have used costly metre-class telescopes to obtain data despite other experiments demonstrating that much more flexible and affordable small aperture telescopes may be suitable for the task. In addition, due to the highly time consuming and weather dependent nature of obtaining photometric observations, many studies have suffered from data sets of limited size, or relied upon simulations to support their claims. With this in mind, an experiment was conducted with the aim of determining the utility of small aperture telescopes for conducting broadband photometry of satellites for the purpose of non-resolved space object identification and characterisation. A 14 inch Celestron CG-14 telescope was used to gain multiple night-long, high temporal resolution data sets of six active geostationary satellites. The results of the experiment cast doubt on the efficacy of some of the previous approaches to obtaining and analysing photometric data. It was discovered that geostationary satellite lightcurves can vary to a greater degree than has generally been recognised, and colour ratios vary considerably with changes in the illumination/observation geometry, making it difficult to use colour for satellite discrimination. Evidence was also detected of variations in the spectral energy distribution of sunlight reflected off satellite surface materials, which could have implications for surface material characterisation and techniques that aim to separate satellite body and solar panel contributions to the total observed spectra.

  4. The surface physicochemistry and adhesiveness of Shewanella are affected by their surface polysaccharides.

    PubMed

    Korenevsky, Anton; Beveridge, Terry J

    2007-06-01

    Shewanella strains have previously been studied with regard to their cell surface ultrastructure and LPS composition. They have now been further characterized with respect to their surface physicochemistry and ability to adhere to haematite. The surfaces of the Shewanella strains were found to be electronegative and hydrophilic, and these properties could be correlated with LPS composition or the presence of capsular polysaccharides. Strains expressing rough LPS with no capsule were more hydrophobic and electronegative than those possessing smooth LPS or capsules. By combining different approaches, such as contact-angle measurement, hydrophilic/hydrophobic chromatography, microelectrophoresis, adhesion assays and calculation of interaction energies, it was shown that electrostatic interactions predominate over hydrophobic interactions at the cell-iron oxide interface. Bacterial adhesion to haematite was significantly reduced in strains expressing smooth LPS or a capsule. These findings remained true for Shewanella strains grown under either aerobic or anaerobic conditions, although the surfaces of anaerobic cells appeared to be less electronegative and more hydrophilic than those of aerobic cells. PMID:17526844

  5. Nutrient losses in runoff from feedlot surfaces as affected by unconsolidated surface materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beef cattle feedlots contain unconsolidated surface materials (USM) (loose manure pack) that accumulate within feedlot pens during a feeding cycle. The effects of varying amounts of USM on feedlot runoff water quality are not well defined. The objectives of this field investigation were to: a) compa...

  6. Visual and radiometric photometry of 1580 Betulia. [asteroid infrared observation

    NASA Technical Reports Server (NTRS)

    Lebofsky, L. A.; Veeder, G. J.; Matson, D. L.; Lebofsky, M. J.

    1978-01-01

    Broadband visual and 10.6-micron photometry of 1580 Betulia was obtained during its close approach to earth in May 1976. The photometry was analyzed by using the 'radiometric method' to derive the radius (2.10 + or - 0.40 km) and albedo (0.108 + or - 0.012) of Betulia. Radar and polarimetric results indicate a radius greater than 3.0 km and a geometric albedo of about 0.05. To be compatible with these results, Betulia was also modeled as having a surface with the thermal characteristics of bare rock rather than those of the 'lunar' regolith model used for previous analysis of radiometry of other asteroids. A 3.7-km radius and a geometric albedo of about 0.04 are compatible with all available observations. Betulia is the first Mars-crossing asteroid found to have such a low albedo, which may be indicative of carbonaceous surface material.

  7. Collected photometry of FK Comae Berenices

    NASA Astrophysics Data System (ADS)

    Jetsu, L.; Tuominen, I.; Antov, A.; Bopp, B. W.; Chugainov, P. F.; Grankin, K. N.; Linnaluoto, S.; Melnikov, S. Yu.; Nations, H. L.; Panov, K. P.; Shevchenko, V. S.

    1994-01-01

    New photometric observations of FK Comae Berenices are combined to the previously published photometry and a firm basis established for the long--term phometric studies of this rapidly rotating late--type giant. The methods used to combine a quarter of a century of observations into a homogeneous set of standard Johnson UBVRI photometry are presented.

  8. Host surface properties affect prepenetration processes in the barley powdery mildew fungus.

    PubMed

    Zabka, Vanessa; Stangl, Michaela; Bringmann, Gerhard; Vogg, Gerd; Riederer, Markus; Hildebrandt, Ulrich

    2008-01-01

    The initial contact between Blumeria graminis f.sp. hordei and its host barley (Hordeum vulgare) takes place on epicuticular waxes at the surfaces of aerial plant organs. Here, the extent to which chemical composition, crystal structure and hydrophobicity of cuticular waxes affect fungal prepenetration processes was explored. The leaf surface properties of barley eceriferum (cer) wax mutants were characterized in detail. Barley leaves and artificial surfaces were used to investigate the early events of fungal infection. Even after epicuticular waxes had been stripped away, cer mutant leaf surfaces did not affect fungal prepenetration properties. Removal of total leaf cuticular waxes, however, resulted in a 20% reduction in conidial germination and differentiation. Two major components of barley leaf wax, hexacosanol and hexacosanal, differed considerably in their ability to effectively trigger conidial differentiation on glass surfaces. While hexacosanol, attaining a maximum hydrophobicity with contact angles of no more than 80 degrees, proved to be noninductive, hexacosanal significantly stimulated differentiation in c. 50% of B. graminis conidia, but only at contact angles > 80 degrees. These results, together with an observed inductive effect of highly hydrophobic, wax-free artificial surfaces, provide new insights into the interplay of physical and chemical surface cues involved in triggering prepenetration processes in B. graminis. PMID:17937760

  9. The lenticular NGC 3115 - A standard for galaxy photometry

    NASA Astrophysics Data System (ADS)

    Capaccioli, M.; Held, E. V.; Nieto, J.-L.

    NGC 3115, a lenticular galaxy that is seen edge-on, is an ideal candidate for surface photometry in virtue of its proximity and absence of close prominent companions. An independent two-dimensional study of NGC 3115 has been made using the high resolution CFH telescope, as well as the ESO and UK Schmidt telescopes (for the outer regions). Light profiles along both main axes were produced for each intensity frame; the results obtained are presented in graphical form.

  10. THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY. X. ULTRAVIOLET TO INFRARED PHOTOMETRY OF 117 MILLION EQUIDISTANT STARS

    SciTech Connect

    Williams, Benjamin F.; Dalcanton, Julianne J.; Weisz, Daniel R.; Byler, Nell; Johnson, L. C. E-mail: jd@astro.washington.edu E-mail: lcjohnso@astro.washington.edu; and others

    2014-11-01

    We have measured stellar photometry with the Hubble Space Telescope Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys in near ultraviolet (F275W, F336W), optical (F475W, F814W), and near infrared (F110W, F160W) bands for 117 million resolved stars in M31. As part of the Panchromatic Hubble Andromeda Treasury survey, we measured photometry with simultaneous point-spread function (PSF) fitting across all bands and at all source positions after precise astrometric image alignment (<5-10 mas accuracy). In the outer disk, the photometry reaches a completeness-limited depth of F475W ∼ 28, while in the crowded, high surface brightness bulge, the photometry reaches F475W ∼ 25. We find that simultaneous photometry and optimized measurement parameters significantly increase the detection limit of the lowest-resolution filters (WFC3/IR) providing color-magnitude diagrams (CMDs) that are up to 2.5 mag deeper when compared with CMDs from WFC3/IR photometry alone. We present extensive analysis of the data quality including comparisons of luminosity functions and repeat measurements, and we use artificial star tests to quantify photometric completeness, uncertainties and biases. We find that the largest sources of systematic error in the photometry are due to spatial variations in the PSF models and charge transfer efficiency corrections. This stellar catalog is the largest ever produced for equidistant sources, and is publicly available for download by the community.

  11. Interactions of bluff-body obstacles with turbulent airflows affecting evaporative fluxes from porous surfaces

    NASA Astrophysics Data System (ADS)

    Haghighi, Erfan; Or, Dani

    2015-11-01

    Bluff-body obstacles interacting with turbulent airflows are common in many natural and engineering applications (from desert pavement and shrubs over natural surfaces to cylindrical elements in compact heat exchangers). Even with obstacles of simple geometry, their interactions within turbulent airflows result in a complex and unsteady flow field that affects surface drag partitioning and transport of scalars from adjacent evaporating surfaces. Observations of spatio-temporal thermal patterns on evaporating porous surfaces adjacent to bluff-body obstacles depict well-defined and persistent zonation of evaporation rates that were used to construct a simple mechanistic model for surface-turbulence interactions. Results from evaporative drying of sand surfaces with isolated cylindrical elements (bluff bodies) subjected to constant turbulent airflows were in good agreement with model predictions for localized exchange rates. Experimental and theoretical results show persistent enhancement of evaporative fluxes from bluff-rough surfaces relative to smooth flat surfaces under similar conditions. The enhancement is attributed to formation of vortices that induce a thinner boundary layer over part of the interacting surface footprint. For a practical range of air velocities (0.5-4.0 m/s), low-aspect ratio cylindrical bluff elements placed on evaporating sand surfaces enhanced evaporative mass losses (relative to a flat surface) by up to 300% for high density of elements and high wind velocity, similar to observations reported in the literature. Concepts from drag partitioning were used to generalize the model and upscale predictions to evaporation from surfaces with multiple obstacles for potential applications to natural bluff-rough surfaces.

  12. TT Arietis: Spectroscopy and Photometry

    NASA Astrophysics Data System (ADS)

    Wu, Xiaoan; Li, Zongyun; Ding, Yuerong; Zhang, Zhousheng; Li, Zili

    2002-04-01

    We report the photometry and spectroscopy of TT Arietis around the turn of the millennium, when the nova-like variable is in high state. A positive superhump since 1997 still exists. A more precise orbital period than before, 0.13755040+/-1.7×10-7 days, is established. The intensity of the Balmer emission core is found to modulate at the superhump period rather than the orbital period and 180° out of phase with continuum. The intensity of Balmer absorption wings is approximately proportional to the continuum flux. The correlation between Balmer lines and continuum provides a new clue to the study of sources of continuum and emission lines. The mass ratio of the binary is found to be in the range of 0.19+/-0.04, which lends strong support to the proposition that superhumps arise from the inner Lindblad 3:1 resonance in TT Ari, as in superoutbursts of SU UMa stars.

  13. CHARACTERIZATION OF SLOAN DIGITAL SKY SURVEY STELLAR PHOTOMETRY

    SciTech Connect

    Fukugita, Masataka; Yasuda, Naoki; Doi, Mamoru; Gunn, James E.; York, Donald G.

    2011-02-15

    We study the photometric properties of stars in the data archive of the Sloan Digital Sky Survey (SDSS), the prime aim being to understand the photometric calibration over the entire data set. It is confirmed that the photometric calibration of point sources is accurately on the system defined by the SDSS standard stars. We have also confirmed that the photometric synthesis of the SDSS spectrophotometric data gives broadband fluxes that agree with the photometry with errors of no more than 0.04 mag and little systematic tilt with wavelength. This verifies that the response functions of the 2.5 m telescope system are well characterized. We locate stars in the SDSS photometric system, so that stars can roughly be classified into spectral classes from the color information. We show how metallicity and surface gravity affect colors, and that stars contained in the SDSS general catalog, plotted in color space, show a distribution that matches well with what is anticipated from the variations of metallicity and surface gravity. The color-color plots are perfectly consistent among the three samples-stars in the SDSS general catalog, SDSS standard stars, and spectrophotometric stars of Gunn and Stryker-especially when some considerations are taken into account of the differences (primarily metallicity) of the samples. We show that the g - r-inverse temperature relation is tight and can be used as a good estimator of the effective temperature of stars over a fairly wide range of effective temperatures. We also confirm that the colors of G2V stars in the SDSS photometric system match well with the Sun.

  14. Characterization of Sloan Digital Sky Survey Stellar Photometry

    NASA Astrophysics Data System (ADS)

    Fukugita, Masataka; Yasuda, Naoki; Doi, Mamoru; Gunn, James E.; York, Donald G.

    2011-02-01

    We study the photometric properties of stars in the data archive of the Sloan Digital Sky Survey (SDSS), the prime aim being to understand the photometric calibration over the entire data set. It is confirmed that the photometric calibration of point sources is accurately on the system defined by the SDSS standard stars. We have also confirmed that the photometric synthesis of the SDSS spectrophotometric data gives broadband fluxes that agree with the photometry with errors of no more than 0.04 mag and little systematic tilt with wavelength. This verifies that the response functions of the 2.5 m telescope system are well characterized. We locate stars in the SDSS photometric system, so that stars can roughly be classified into spectral classes from the color information. We show how metallicity and surface gravity affect colors, and that stars contained in the SDSS general catalog, plotted in color space, show a distribution that matches well with what is anticipated from the variations of metallicity and surface gravity. The color-color plots are perfectly consistent among the three samples—stars in the SDSS general catalog, SDSS standard stars, and spectrophotometric stars of Gunn & Stryker—especially when some considerations are taken into account of the differences (primarily metallicity) of the samples. We show that the g - r-inverse temperature relation is tight and can be used as a good estimator of the effective temperature of stars over a fairly wide range of effective temperatures. We also confirm that the colors of G2V stars in the SDSS photometric system match well with the Sun.

  15. Surface shape affects the three-dimensional exploratory movements of nocturnal arboreal snakes.

    PubMed

    Jayne, Bruce C; Olberding, Jeffrey P; Athreya, Dilip; Riley, Michael A

    2012-12-01

    Movement and searching behaviors at diverse spatial scales are important for understanding how animals interact with their environment. Although the shapes of branches and the voids in arboreal habitats seem likely to affect searching behaviors, their influence is poorly understood. To gain insights into how both environmental structure and the attributes of an animal may affect movement and searching, we compared the three-dimensional exploratory movements of snakes in the dark on two simulated arboreal surfaces (disc and horizontal cylinder). Most of the exploratory movements of snakes in the dark were a small fraction of the distances they could reach while bridging gaps in the light. The snakes extended farther away from the edge of the supporting surface at the ends of the cylinder than from the sides of the cylinder or from any direction from the surface of the disc. The exploratory movements were not random, and the surface shape and three-dimensional directions had significant interactive effects on how the movements were structured in time. Thus, the physical capacity for reaching did not limit the area that was explored, but the shape of the supporting surface and the orientation relative to gravity did create biased searching patterns. PMID:23052853

  16. Theory of wide-angle photometry from standard stars

    NASA Technical Reports Server (NTRS)

    Usher, Peter D.

    1989-01-01

    Wide angle celestial structures, such as bright comet tails and nearby galaxies and clusters of galaxies, rely on photographic methods for quantified morphology and photometry, primarily because electronic devices with comparable resolution and sky coverage are beyond current technological capability. The problem of the photometry of extended structures and of how this problem may be overcome through calibration by photometric standard stars is examined. The perfect properties of the ideal field of view are stated in the guise of a radiometric paraxial approximation, in the hope that fields of view of actual telescopes will conform. Fundamental radiometric concepts are worked through before the issue of atmospheric attenuation is addressed. The independence of observed atmospheric extinction and surface brightness leads off the quest for formal solutions to the problem of surface photometry. Methods and problems of solution are discussed. The spectre is confronted in the spirit of standard stars and shown to be chimerical in that light, provided certain rituals are adopted. After a brief discussion of Baker-Sampson polynomials and the vexing issue of saturation, a pursuit is made of actual numbers to be expected in real cases. While the numbers crunched are gathered ex nihilo, they demonstrate the feasibility of Newton's method in the solution of this overdetermined, nonlinear, least square, multiparametric, photometric problem.

  17. Galaxy photometry at faint light levels - Interaction with the environment

    NASA Astrophysics Data System (ADS)

    Carter, D.

    Interactions of two disk galaxies are considered, taking into account findings which suggest that violent relaxation in the stellar component of a merging system operates on a shorter time scale than dissipation in the gaseous component. Interactions between disk and elliptical galaxies are also discussed along with tidal distension of the envelopes of galaxies, cD galaxies, the halos of spiral galaxies, isophotometry, interacting spiral galaxies, dust lanes, the environment of radio galaxies, and future work. It is pointed out that photometry, particularly panoramic surface photometry, can provide important evidence on the effects of mergers, accretion, and tides on galaxies. More sensitive X-ray telescopes will make it possible to observe the accretion by galaxies of the hot intergalactic medium. Such an accretion is, perhaps, the most important environmental effect on galaxies.

  18. Do Aging and Tactile Noise Stimulation Affect Responses to Support Surface Translations in Healthy Adults?

    PubMed Central

    Pourmoghaddam, Amir; Lee, Beom-Chan; Layne, Charles S.

    2016-01-01

    Appropriate neuromuscular responses to support surface perturbations are crucial to prevent falls, but aging-related anatomical and physiological changes affect the appropriateness and efficiency of such responses. Low-level noise application to sensory receptors has shown to be effective for postural improvement in a variety of different balance tasks, but it is unknown whether this intervention may have value for improvement of corrective postural responses. Ten healthy younger and ten healthy older adults were exposed to sudden backward translations of the support surface. Low-level noise (mechanical vibration) to the foot soles was added during random trials and temporal (response latency) and spatial characteristics (maximum center-of-pressure excursion and anterior-posterior path length) of postural responses were assessed. Mixed-model ANOVA was applied for analysis of postural response differences based on age and vibration condition. Age affected postural response characteristics, but older adults were well able to maintain balance when exposed to a postural perturbation. Low-level noise application did not affect any postural outcomes. Healthy aging affects some specific measures of postural stability, and in high-functioning older individuals, a low-level noise intervention may not be valuable. More research is needed to investigate if recurring fallers and neuropathy patients could benefit from the intervention in postural perturbation tasks. PMID:27195007

  19. Surface chemical functionalities affect the behavior of human adipose-derived stem cells in vitro

    NASA Astrophysics Data System (ADS)

    Liu, Xujie; Feng, Qingling; Bachhuka, Akash; Vasilev, Krasimir

    2013-04-01

    This study examines the effect of surface chemical functionalities on the behavior of human adipose-derived stem cells (hASCs) in vitro. Plasma polymerized films rich in amine (sbnd NH2), carboxyl (sbnd COOH) and methyl (sbnd CH3), were generated on hydroxyapatite (HAp) substrates. The surface chemical functionalities were characterized by X-ray photoelectron spectroscopy (XPS). The ability of different substrates to absorb proteins was evaluated. The results showed that substrates modified with hydrophilic functional group (sbnd COOH and sbnd NH2) can absorb more proteins than these modified with more hydrophobic functional group (sbnd CH3). The behavior of human adipose-derived stem cells (hASCs) cultured on different substrates was investigated in vitro: cell counting kit-8 (CCK-8) analysis was used to characterize cell proliferation, scanning electronic microscopy (SEM) analysis was used to characterize cell morphology and alkaline phosphatase (ALP) activity analysis was used to account for differentiation. The results of this study demonstrated that the sbnd NH2 modified surfaces encourage osteogenic differentiation; the sbnd COOH modified surfaces promote cell adhesion and spreading and the sbnd CH3 modified surfaces have the lowest ability to induce osteogenic differentiation. These findings confirmed that the surface chemical states of biomaterials can affect the behavior of hASCs in vitro.

  20. Plasma treatment of polystyrene thin films affects more than the surface.

    PubMed

    Calchera, Angela R; Curtis, Alexander D; Patterson, James E

    2012-07-25

    Plasma treatment of polymer materials introduces chemical functionalities and modifies the material to make the native hydrophobic surface more hydrophilic. It is generally assumed that this process only affects the surface of the material. We used vibrationally resonant sum-frequency generation spectroscopy to observe changes in the orientation of phenyl groups in polystyrene (PS) thin films on various substrates before and after plasma treatment. VR-SFG selectively probes regions of broken symmetry, such as surfaces, but can also detect the emergence of anisotropy. On dielectric substrates, such as fused silica, the spectroscopic peak corresponding to the symmetric stretching (ν2) mode of the phenyl rings was undetectable after plasma treatment, showing that surface phenyl rings were altered. This peak also diminished on conducting substrates, but the intensity of another peak corresponding to the same mode in a bulklike environment increased significantly, suggesting that plasma treatment induces partial ordering of the bulk polymer. This ordering is seen on conducting substrates even when the polymer is not directly exposed to the plasma. Annealing reverses these effects on the polystyrene bulk; however, the surface phenyl rings do not return to the orientation observed for untreated films. These results call into question the assumption that the effects of plasma treatment are limited to the free surface and opens up other possibilities for material modification with low-temperature plasmas. PMID:22642391

  1. Meteor44 Video Meteor Photometry

    NASA Technical Reports Server (NTRS)

    Swift, Wesley R.; Suggs, Robert M.; Cooke, William J.

    2004-01-01

    Meteor44 is a software system developed at MSFC for the calibration and analysis of video meteor data. The dynamic range of the (8bit) video data is extended by approximately 4 magnitudes for both meteors and stellar images using saturation compensation. Camera and lens specific saturation compensation coefficients are derived from artificial variable star laboratory measurements. Saturation compensation significantly increases the number of meteors with measured intensity and improves the estimation of meteoroid mass distribution. Astrometry is automated to determine each image's plate coefficient using appropriate star catalogs. The images are simultaneously intensity calibrated from the contained stars to determine the photon sensitivity and the saturation level referenced above the atmosphere. The camera s spectral response is used to compensate for stellar color index and typical meteor spectra in order to report meteor light curves in traditional visual magnitude units. Recent efforts include improved camera calibration procedures, long focal length 'streak' meteor photometry and two-station track determination. Meteor44 has been used to analyze data from the 2001, 2002 and 2003 MSFC Leonid observational campaigns as well as several lesser showers. The software is interactive and can be demonstrated using data from recent Leonid campaigns.

  2. First photometry results from Gaia

    NASA Astrophysics Data System (ADS)

    Brown, Anthony

    2015-08-01

    An overview of the Gaia Photometric Processing is presented. The Gaia photometry consists of the white light (330-1050 nm) G-band, and low resolution spectrophotometry realized by two prisms dispersing all the light entering the field of view. One disperser - called BP for Blue Photometer- operates in the wavelength range 330-680 nm; the other - called RP for Red Photometer - covers the wavelength range 640-1050 nm. The light collected by BP and RP can also be integrated into two broad bands, G_BP and G_RP.This photometric data reduction is based on the overall principle of a self-calibrating system improved by iteration. The input data includes flux (G, G_BP, G_RP) and the low-resolution spectral data. The calibration models and algorithms used are described. Initial validation results are shown which indicate the photometric quality of the preliminary calibrated data. Expectations for the quality of the photometric data to be included in the first public data release (mid-2016) are discussed.

  3. WFPC2 Stellar Photometry with HSTphot

    NASA Technical Reports Server (NTRS)

    Dolphin, Andrew E.

    2000-01-01

    HSTphot, a photometry package designed to handle the undersampled PSFs found in WFPC2 images, is introduced and described, as well as some of the considerations that have to be made in order to obtain accurate PSF-fitting stellar photometry with WFPC2 data. Tests of HSTphot's internal reliability are made using multiple observations of the same field, and tests of external reliability are made by comparing with DoPHOT reductions of the same data. Subject headz'ngs: techniques: photometric

  4. L' AND M' Photometry Of Ultracool Dwarfs

    NASA Technical Reports Server (NTRS)

    Marley, M. S.; Tsvetanov, Z. I.; Vrba, F. J.; Henden, A. A.; Luginbuhl, C. B.

    2004-01-01

    We have compiled L' (3.4-4.1 microns) and M' (4.6- 4.8 microns) photometry of 63 single and binary M, L, and T dwarfs obtained at the United Kingdom Infrared Telescope using the Mauna Kea Observatory filter set. This compilation includes new L' measurements of eight L dwarfs and 13 T dwarfs and new M' measurements of seven L dwarfs, five T dwarfs, and the M1 dwarf Gl 229A. These new data increase by factors of 0. 6 and 1.6, respectively, the numbers of ultracool dwarfs T (sub eff) photometry, and trigonometric parallaxes are available, and we estimate these quantities for nine other dwarfs whose parallaxes and flux-calibrated spectra have been obtained. BC(SUB K) is a well-behaved function of near-infrared spectral type with a dispersion of approx. 0.1 mag for types M6-T5 it is significantly more scattered for types T5-T9. T (sub eff) declines steeply and monotonically for types M6-L7 and T4-T9, but it is nearly constant at approx. 1450 K for types L7-T4 with assumed ages of approx. 3 Gyr. This constant T(sub eff) is evidenced by nearly unchanging values of L'-M' between types L6 and T3. It also supports recent models that attribute the changing near-infrared luminosities and spectral features across the L-T transition to the rapid migration, disruption, and/or thinning of condensate clouds over a narrow range of T(sub eff). The L' and M' luminosities of early-T dwarfs do not exhibit the pronounced humps or inflections previously noted in l through K bands, but insufficient data exist for types L6-T5 to assert that M(Sub L') and M(sub M') are strictly monotonic within this range of typew. We compare the observed K, L', and M' luminosities of L and T dwarfs in our sample with those predicted by precipitation-cloud-free models for varying surface gravities and sedimentation efficiencies.

  5. BVRI PHOTOMETRY OF 53 UNUSUAL ASTEROIDS

    SciTech Connect

    Ye, Q.-Z.

    2011-02-15

    We present the results of BVRI photometry and classification of 53 unusual asteroids, including 35 near-Earth asteroids (NEAs), 6 high eccentricity/inclination asteroids, and 12 recently identified asteroid-pair candidates. Most of these asteroids were not classified prior to this work. For the few asteroids that have been previously studied, the results are generally in agreement. In addition to observing and classifying these objects, we merge the results from severalphotometric/spectroscopic surveys to create the largest-ever sample with 449 spectrally classified NEAs for statistical analysis. We identify a 'transition point' of the relative number of C/X-like and S-like NEAs at H {approx} 18 {r_reversible} D {approx} 1 km with confidence level at {approx}95% or higher. We find that the C/X-like:S-like ratio for 18 {<=} H < 22 is about twice as high as that of H < 18 (0.33 {+-} 0.04 versus 0.17 {+-} 0.02), virtually supporting the hypothesis that smaller NEAs generally have less weathered surfaces (therefore less reddish appearance) due to younger collision ages.

  6. Processes Affecting the Annual Surface Energy Budget at High-Latitude Terrestrial Sites

    NASA Astrophysics Data System (ADS)

    Persson, P. O. G.; Stone, R. S.; Grachev, A.; Matrosova, L.

    2012-04-01

    Instrumentation at four Study of Environmental Arctic Change (SEARCH) sites (Barrow, Eureka, Alert, and Tiksi) have been enhanced in the past 6 years, including during the 2007-2008 IPY. Data from these sites are used to investigate the annual cycle of the surface energy budget (SEB), its coupling to atmospheric processes, and for Alert, its interannual variability. The comprehensive data sets are useful for showing interactions between the atmosphere, surface, and soil at high temporal resolution throughout the annual cycle. Processes that govern the SEB variability at each site are identified, and their impacts on the SEB are quantified. For example, mesoscale modulation of the SEB caused by forcing from the local terrain (downslope wind events) and coastlines (sea and land breezes) are significant at Alert and Eureka, with these processes affecting both radiative, turbulent, and ground heat flux terms in the SEB. Sub-seasonal and interannual variations in atmospheric processes and SEB impact soil thermal structures, such as the depth and timing of the summer active layer. These analyses provide an improved understanding of the processes producing changes in surface and soil temperature, linking them through the SEB as affected by atmospheric processes.

  7. The Panchromatic Hubble Andromeda Treasury Survey: UV-IR Photometry of 117 Million Stars

    NASA Astrophysics Data System (ADS)

    Williams, Benjamin F.; Lang, Dustin; Dalcanton, Julianne; Dolphin, Andrew E.; Weisz, Daniel R.; Johnson, Lent C.; Byler, Nell; Gregersen, Dylan; Seth, Anil; Girardi, Leo; PHAT Survey Team

    2015-01-01

    We have measured resolved stellar photometry using HST/WFC3 and HST/ACS imaging in near ultraviolet (F275W, F336W), optical (F475W, F814W), and near infrared (F110W, F160W) with simultaneous point spread function fitting across all bands at all source positions. All images were aligned to 5-10 milliarcsecond relative accuracy and to 50 milliarcsec global accuracy. In the outer disk, the photometry reaches a completeness-limited depth of F475W~28, while in the crowded, high surface brightness bulge, the photometry reaches F475W~25. We find that simultaneous photometry and optimized measurement parameters significantly increase the detection limit of the lowest resolution filters (WFC3/IR) providing color-magnitude diagrams that are up to 2.5 magnitudes deeper when compared with color-magnitude diagrams from WFC3/IR photometry alone. This stellar catalog is the largest ever produced for equidistant sources, and is publicly available for download by the community. The quality of the photometry catalog, as well as examples of some initial results from model fitting will be discussed. PHAT is supported by HST GO-12055 administered by NASA.

  8. Inhibition of Cell Surface Export of Group A Streptococcal Anchorless Surface Dehydrogenase Affects Bacterial Adherence and Antiphagocytic Properties

    PubMed Central

    Bol, Grgory; Jin, Hong; Pancholi, Vijay

    2005-01-01

    Surface dehydrogenase (SDH) is an anchorless, multifunctional protein displayed on the surfaces of group A Streptococcus (GAS) organisms. SDH is encoded by a single gene, sdh (gap or plr) that is essential for bacterial survival. Hence, the resulting nonfeasibility of creating a knockout mutant is a major limiting factor in studying its role in GAS pathogenesis. An insertion mutagenesis strategy was devised in which a nucleotide sequence encoding a hydrophobic tail of 12 amino acids (337IVLVGLVMLLLS348) was added at the 3? end of the sdh gene, successfully creating a viable mutant strain (M1-SDHHBtail). In this mutant strain, the SDHHBtail protein was not secreted in the medium but was retained in the cytoplasm and to some extent trapped within the cell wall. Hence, SDHHBtail was not displayed on the GAS surface. The mutant strain, M1-SDHHBtail, grew at the same rate as the wild-type strain. The SDHHBtail protein displayed the same GAPDH activity as the wild-type SDH protein. Although the whole-cell extracts of the wild-type and mutant strains showed similar GAPDH activities, cell wall extracts of the mutant strain showed 5.5-fold less GAPDH activity than the wild-type strain. The mutant strain, M1-SDHHBtail, bound significantly less human plasminogen, adhered poorly to human pharyngeal cells, and lost its innate antiphagocytic activity. These results indicate that the prevention of the cell surface export of SDH affects the virulence properties of GAS. The anchorless SDH protein, thus, is an important virulence factor. PMID:16177295

  9. Dry heat treatment affects wheat bran surface properties and hydration kinetics.

    PubMed

    Jacobs, Pieter J; Hemdane, Sami; Delcour, Jan A; Courtin, Christophe M

    2016-07-15

    Heat stabilization of wheat bran aims at inactivation of enzymes which may cause rancidity and processability issues. Such treatments may however cause additional unanticipated phenomena which may affect wheat bran technological properties. In this work, the impact of toasting on wheat bran hydration capacity and hydration kinetics was studied. Hydration properties were assessed using the Enslin-Neff and drainage centrifugation water retention capacity methods, thermogravimetric analysis and contact angle goniometry, next to more traditional methods. While equilibrium hydration properties of bran were not affected by the heat treatment, the rate at which the heat treated bran hydrated was, however, very significantly reduced compared to the untreated bran. This phenomenon was found to originate from the formation of a lipid coating during the treatment rendering the bran surface hydrophobic. These insights help to understand and partially account for the modified processability of heat treated bran in food applications. PMID:26948645

  10. Differential Photometry at 1612 MHz

    NASA Astrophysics Data System (ADS)

    Lewis, B. Murray

    2009-01-01

    The 1612 MHz light curves of high latitude OH/IR stars have been observed for several years with the Arecibo 305m telescope, to derive the light-travel time diameter of their shells from the phase difference between their red and blue shifted peaks, and to look for secular evolution of their masers. However, direct intensity measurements are always limited by the extent to which the telescope's characteristics can be removed. These, in Arecibo's case, are subject to changes in the weight distribution about the structure over time, to the functioning of the vertical tie-down system, which can be interrupted by thunder storms, and by temperature-related zenith angle effects during daytime observations. Nevertheless, all of these limitations are neutralized when the ratio of the two peaks is used as the observed parameter. This form of differential photometry often results in clean light curves, though the ratio may still be perturbed by RFI, by interstellar scintillation, and more predictably by noise. The increased sensitivity of this observing mode readily detects (1) any differential evolution of the two masers, as well as (2) highlighting changes in masing gain between the two peaks around the pulsation cycle, that in turn are indicative of the operation of partially rather than fully saturated masers. In many of our light-curves there are abrupt changes in the ratio of the peak intensities at a constant pulsation phase. These are interpreted as being due to the onset of dust formation at that phase of the pulsation cycle, with a consequent abrupt change in the reprocessing of the stellar SED, and hence to an abrupt change in the maser pump. This is a feature of the Gray, Howe & Lewis (MN 364, 783 (2005)) maser model. Examples of these effects will be shown.

  11. DIRECT COMPARISON OF KINETIC AND LOCAL EQUILIBRIUM FORMULATIONS FOR SOLUTE TRANSPORT AFFECTED BY SURFACE REACTIONS.

    USGS Publications Warehouse

    Bahr, Jean M.; Rubin, Jacob

    1987-01-01

    Modeling transport of reacting solutes in porous media often requires a choice between models based on the local equilibrium assumption (LEA) and models involving reaction kinetics. Direct comparison of the mathematical formulations for these two types of transport models can aid in this choice. For cases of transport affected by surface reaction, such a comparison is made possible by a new derivation procedure. This procedure yields a kinetics-based formulation that is the sum of the LEA formulation and one or more kinetically influenced terms. The dimensionless form of the new kinetics-based formulation facilitates identification of critical parameter groupings which control the approach to transport behavior consistent with LEA model predictions. Results of numerical experiments demonstrate that criteria for LEA applicability can be expressed conveniently in terms of these parameter groupings. The derivation procedure is demonstrated for examples of surface reactions including first-order reversible sorption, Langmuir-type kinetics and binary, homovalent ion exchange.

  12. How will surface treatments affect the translucency of porcelain laminate veneers?

    PubMed Central

    Turgut, Sedanur; Ayaz, Elif Aydogan; Korkmaz, Fatih Mehmet; Ulusoy, Kıvanç Utku; Bagis, Yildirim Hakan

    2014-01-01

    PURPOSE The purpose of this study was to evaluate whether surface treatments affect the translucency of laminate veneers with different shades and thicknesses. MATERIALS AND METHODS A total of 224 disc-shaped ceramic veneers were prepared from A1, A3, HT (High Translucent) and HO (High Opaque) shades of IPS e.max Press (Ivoclar Vivadent) with 0.5 mm and 1.0 mm thicknesses. The ceramics were divided into four groups for surface treatments. Group C: no surface treatments; Group HF: etched with hydrofluoric acid; Group SB: sandblasted with 50-µm Al2O3; and Group L; irradiated with an Er;YAG laser. A translucent shade of resin cement (Rely X Veneer, 3M ESPE) was chosen for cementation. The color values of the veneers were measured with a colorimeter and translucency parameter (TP) values were calculated. A three-way ANOVA with interactions for TP values was performed and Bonferroni tests were used when appropriate (α=0.05). RESULTS There were significant interactions between the surface treatments, ceramic shades and thicknesses (P=.001). For the 0.5-mm-thick specimens there were significant differences after the SB and L treatments. There was no significant difference between the HF and C treatments for any shades or thicknesses (P>.05). For the 1-mm-thick ceramics, there was only a significant difference between the L and C treatments for the HT shade ceramics (P=.01). There were also significant differences between the SB and C treatments except not for the HO shades (P=.768). CONCLUSION The SB and L treatments caused laminate veneers to become more opaque; however, HF treatment did not affect the TP values. When the laminate veneers were thinner, both the shade of the ceramic and the SB and laser treatments had a greater effect on the TP values. PMID:24605200

  13. Surface charge affects cellular uptake and intracellular trafficking of chitosan-based nanoparticles.

    PubMed

    Yue, Zhan-Guo; Wei, Wei; Lv, Pi-Ping; Yue, Hua; Wang, Lian-Yan; Su, Zhi-Guo; Ma, Guang-Hui

    2011-07-11

    Chitosan-based nanoparticles (NPs) are widely used in drug delivery, device-based therapy, tissue engineering, and medical imaging. In this aspect, a clear understanding of how physicochemical properties of these NPs affect the cytological response is in high demand. The objective of this study is to evaluate the effect of surface charge on cellular uptake profiles (rate and amount) and intracellular trafficking. We fabricate three kinds of NPs (∼ 215 nm) with different surface charge via SPG membrane emulsification technique and deposition method. They possess uniform size as well as identical other physicochemical properties, minimizing any differences between the NPs except for surface charge. Moreover, we extend our research to eight cell lines, which could help to obtain a representative conclusion. Results show that the cellular uptake rate and amount are both positively correlated with the surface charge in all cell line. Subsequent intracellular trafficking indicates that some of positively charged NPs could escape from lysosome after being internalized and exhibit perinuclear localization, whereas the negatively and neutrally charged NPs prefer to colocalize with lysosome. These results are critical in building the knowledge base required to design chitosan-based NPs to be used efficiently and specifically. PMID:21657799

  14. Amylolytic hydrolysis of native starch granules affected by granule surface area.

    PubMed

    Kim, J C; Kong, B W; Kim, M J; Lee, S H

    2008-11-01

    Initial stage of hydrolysis of native starch granules with various amylolytic enzymes, alpha-amylase from Bacillus subtilis, glucoamylase I (GA-I) and II (GA-II) from Aspergillus niger, and beta-amylase from sweet potato showed that the reaction was apparently affected by a specific surface area of the starch granules. The ratios of the reciprocal of initial velocity of each amylolytic hydrolysis for native potato and maize starch to that for rice with the amylolytic enzymes were nearly equivalent to the ratio of surface area per mass of the 2 starch granules to that of rice, that is, 6.94 and 2.25, respectively. Thus, the reciprocal of initial velocity of each enzymatic hydrolysis as expressed in a Lineweaver-Burk plot was a linear function of the reciprocal of surface area for each starch granule. As a result, it is concluded that amylolytic hydrolysis of native starch granules is governed by the specific surface area, not by the mass concentration, of each granule. PMID:19021791

  15. Optimized Structure and Vibrational Properties by Error Affected Potential Energy Surfaces

    PubMed Central

    Zen, Andrea; Zhelyazov, Delyan; Guidoni, Leonardo

    2013-01-01

    The precise theoretical determination of the geometrical parameters of molecules at the minima of their potential energy surface and of the corresponding vibrational properties are of fundamental importance for the interpretation of vibrational spectroscopy experiments. Quantum Monte Carlo techniques are correlated electronic structure methods promising for large molecules, which are intrinsically affected by stochastic errors on both energy and force calculations, making the mentioned calculations more challenging with respect to other more traditional quantum chemistry tools. To circumvent this drawback in the present work, we formulate the general problem of evaluating the molecular equilibrium structures, the harmonic frequencies, and the anharmonic coefficients of an error affected potential energy surface. The proposed approach, based on a multidimensional fitting procedure, is illustrated together with a critical evaluation of systematic and statistical errors. We observe that the use of forces instead of energies in the fitting procedure reduces the statistical uncertainty of the vibrational parameters by 1 order of magnitude. Preliminary results based on variational Monte Carlo calculations on the water molecule demonstrate the possibility to evaluate geometrical parameters and harmonic and anharmonic coefficients at this level of theory with an affordable computational cost and a small stochastic uncertainty (<0.07% for geometries and <0.7% for vibrational properties). PMID:24093004

  16. Seat surface inclination may affect postural stability during Boccia ball throwing in children with cerebral palsy.

    PubMed

    Tsai, Yung-Shen; Yu, Yi-Chen; Huang, Po-Chang; Cheng, Hsin-Yi Kathy

    2014-12-01

    The aim of the study was to examine how seat surface inclination affects Boccia ball throwing movement and postural stability among children with cerebral palsy (CP). Twelve children with bilateral spastic CP (3 with gross motor function classification system Level I, 5 with Level II, and 4 with Level III) participated in this study. All participants underwent pediatric reach tests and ball throwing performance analyses while seated on 15° anterior- or posterior-inclined, and horizontal surfaces. An electromagnetic motion analysis system was synchronized with a force plate to assess throwing motion and postural stability. The results of the pediatric reach test (p = 0.026), the amplitude of elbow movement (p = 0.036), peak vertical ground reaction force (PVGRF) (p < 0.001), and movement range of the center of pressure (COP) (p < 0.020) were significantly affected by seat inclination during throwing. Post hoc comparisons showed that anterior inclination allowed greater amplitude of elbow movement and PVGRF, and less COP movement range compared with the other inclines. Posterior inclination yielded less reaching distance and PVGRF, and greater COP movement range compared with the other inclines. The anterior-inclined seat yielded superior postural stability for throwing Boccia balls among children with bilateral spastic CP, whereas the posterior-inclined seat caused difficulty. PMID:25241116

  17. Osteoclasts but not osteoblasts are affected by a calcified surface treated with zoledronic acid in vitro

    SciTech Connect

    Schindeler, Aaron . E-mail: AaronS@chw.edu.au; Little, David G.

    2005-12-16

    Bisphosphonates are potent inhibitors of osteoclast-mediated bone resorption. Recent interest has centered on the effects of bisphosphonates on osteoblasts. Chronic dosing of osteoblasts with solubilized bisphosphonates has been reported to enhance osteogenesis and mineralization in vitro. However, this methodology poorly reflects the in vivo situation, where free bisphosphonate becomes rapidly bound to mineralized bone surfaces. To establish a more clinically relevant cell culture model, we cultured bone cells on calcium phosphate coated quartz discs pre-treated with the potent nitrogen-containing bisphosphonate, zoledronic acid (ZA). Binding studies utilizing [{sup 14}C]-labeled ZA confirmed that the bisphosphonate bound in a concentration-dependent manner over the 1-50 {mu}M dose range. When grown on ZA-treated discs, the viability of bone-marrow derived osteoclasts was greatly reduced, while the viability and mineralization of the osteoblastic MC3T3-E1 cell line were largely unaffected. This suggests that only bone resorbing cells are affected by bound bisphosphonate. However, this system does not account for transient exposure to unbound bisphosphonate in the hours following a clinical dosing. To model this event, we transiently treated osteoblasts with ZA in the absence of a calcified surface. Osteoblasts proved highly resistant to all transitory treatment regimes, even when utilizing ZA concentrations that prevented mineralization and/or induced cell death when dosed chronically. This study represents a pharmacologically more relevant approach to modeling bisphosphonate treatment on cultured bone cells and implies that bisphosphonate therapies may not directly affect osteoblasts at bone surfaces.

  18. Improving Kepler Pipeline Sensitivity with Pixel Response Function Photometry.

    NASA Astrophysics Data System (ADS)

    Morris, Robert L.; Bryson, Steve; Jenkins, Jon Michael; Smith, Jeffrey C

    2014-06-01

    We present the results of our investigation into the feasibility and expected benefits of implementing PRF-fitting photometry in the Kepler Science Processing Pipeline. The Kepler Pixel Response Function (PRF) describes the expected system response to a point source at infinity and includes the effects of the optical point spread function, the CCD detector responsivity function, and spacecraft pointing jitter. Planet detection in the Kepler pipeline is currently based on simple aperture photometry (SAP), which is most effective when applied to uncrowded bright stars. Its effectiveness diminishes rapidly as target brightness decreases relative to the effects of noise sources such as detector electronics, background stars, and image motion. In contrast, PRF photometry is based on fitting an explicit model of image formation to the data and naturally accounts for image motion and contributions of background stars. The key to obtaining high-quality photometry from PRF fitting is a high-quality model of the system's PRF, while the key to efficiently processing the large number of Kepler targets is an accurate catalog and accurate mapping of celestial coordinates onto the focal plane. If the CCD coordinates of stellar centroids are known a priori then the problem of PRF fitting becomes linear. A model of the Kepler PRF was constructed at the time of spacecraft commissioning by fitting piecewise polynomial surfaces to data from dithered full frame images. While this model accurately captured the initial state of the system, the PRF has evolved dynamically since then and has been seen to deviate significantly from the initial (static) model. We construct a dynamic PRF model which is then used to recover photometry for all targets of interest. Both simulation tests and results from Kepler flight data demonstrate the effectiveness of our approach. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA’s Science Mission Directorate.Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA’s Science Mission Directorate.

  19. Eos, Koronis, and Maria Family Asteroids: Infrared (JHK) Photometry

    NASA Technical Reports Server (NTRS)

    Veeder, Glenn J.; Matson, Dennis L.; Owensby, Pamela D.; Gradie, Jonathan C.; Bell, Jeffrey F.; Tedesco, Edward F.

    1995-01-01

    Infrared photometry at 1.2, 1.6, and 2.2 micrometer (JHK) is reported for 56 asteroids in the Eos, Koronis and, Maria dynamical families. These data are consistent with similar surface composition for all of the asteroids of each family. The infrared colors within each family cluster in the region observed for the S taxonomic class, but Eos asteroids may belong to a separable K class. Asteroid 243 Ida, which was observed by the Galileo spacecraft, is a typical member of the Koronis family. The average infrared colors of the Maria family are slightly redder than those of the Eos and Koronis families.

  20. Biofilm Formation by the Fish Pathogen Flavobacterium columnare: Development and Parameters Affecting Surface Attachment

    PubMed Central

    Cai, Wenlong; De La Fuente, Leonardo

    2013-01-01

    Flavobacterium columnare is a bacterial fish pathogen that affects many freshwater species worldwide. The natural reservoir of this pathogen is unknown, but its resilience in closed aquaculture systems posits biofilm as the source of contagion for farmed fish. The objectives of this study were (i) to characterize the dynamics of biofilm formation and morphology under static and flow conditions and (ii) to evaluate the effects of temperature, pH, salinity, hardness, and carbohydrates on biofilm formation. Nineteen F. columnare strains, including representatives of all of the defined genetic groups (genomovars), were compared in this study. The structure of biofilm was characterized by light microscopy, confocal laser scanning microscopy, and scanning electron microscopy. F. columnare was able to attach to and colonize inert surfaces by producing biofilm. Surface colonization started within 6 h postinoculation, and microcolonies were observed within 24 h. Extracellular polysaccharide substances and water channels were observed in mature biofilms (24 to 48 h). A similar time course was observed when F. columnare formed biofilm in microfluidic chambers under flow conditions. The virulence potential of biofilm was confirmed by cutaneous inoculation of channel catfish fingerlings with mature biofilm. Several physicochemical parameters modulate attachment to surfaces, with the largest influence being exerted by hardness, salinity, and the presence of mannose. Maintenance of hardness and salinity values within certain ranges could prevent biofilm formation by F. columnare in aquaculture systems. PMID:23851087

  1. Seismic signatures of carbonate caves affected by near-surface absorptions

    NASA Astrophysics Data System (ADS)

    Rao, Ying; Wang, Yanghua

    2015-12-01

    The near-surface absorption within a low-velocity zone generally has an exponential attenuation effect on seismic waves. But how does this absorption affect seismic signatures of karstic caves in deep carbonate reservoirs? Seismic simulation and analysis reveals that, although this near-surface absorption attenuates the wave energy of a continuous reflection, it does not alter the basic kinematic shape of bead-string reflections, a special seismic characteristic associated with carbonate caves in the Tarim Basin, China. Therefore, the bead-strings in seismic profiles can be utilized, with a great certainty, for interpreting the existence of caves within the deep carbonate reservoirs and for evaluating their pore spaces. Nevertheless, the difference between the central frequency and the peak frequency is increased along with the increment in the absorption. While the wave energy of bead-string reflections remains strong, due to the interference of seismic multiples generated by big impedance contrast between the infill materials of a cave and the surrounding carbonate rocks, the central frequency is shifted linearly with respect to the near-surface absorption. These two features can be exploited simultaneously, for a stable attenuation analysis of field seismic data.

  2. Biofilm formation by the fish pathogen Flavobacterium columnare: development and parameters affecting surface attachment.

    PubMed

    Cai, Wenlong; De La Fuente, Leonardo; Arias, Covadonga R

    2013-09-01

    Flavobacterium columnare is a bacterial fish pathogen that affects many freshwater species worldwide. The natural reservoir of this pathogen is unknown, but its resilience in closed aquaculture systems posits biofilm as the source of contagion for farmed fish. The objectives of this study were (i) to characterize the dynamics of biofilm formation and morphology under static and flow conditions and (ii) to evaluate the effects of temperature, pH, salinity, hardness, and carbohydrates on biofilm formation. Nineteen F. columnare strains, including representatives of all of the defined genetic groups (genomovars), were compared in this study. The structure of biofilm was characterized by light microscopy, confocal laser scanning microscopy, and scanning electron microscopy. F. columnare was able to attach to and colonize inert surfaces by producing biofilm. Surface colonization started within 6 h postinoculation, and microcolonies were observed within 24 h. Extracellular polysaccharide substances and water channels were observed in mature biofilms (24 to 48 h). A similar time course was observed when F. columnare formed biofilm in microfluidic chambers under flow conditions. The virulence potential of biofilm was confirmed by cutaneous inoculation of channel catfish fingerlings with mature biofilm. Several physicochemical parameters modulate attachment to surfaces, with the largest influence being exerted by hardness, salinity, and the presence of mannose. Maintenance of hardness and salinity values within certain ranges could prevent biofilm formation by F. columnare in aquaculture systems. PMID:23851087

  3. Photographic stellar photometry with the PDS microdensitometer

    NASA Technical Reports Server (NTRS)

    Stetson, P. B.

    1979-01-01

    A technique for photographic stellar photometry with the PDS microdensitometer is described. It employs a least-squares fit to a model density profile to derive an instrumental magnitude index, an image-abnormality index, and the local value of the background density for each image. The instrumental magnitude index is calibrated in terms of true magnitude by the same methods as for iris photometry. A preliminary test of the method using plates of the open cluster NGC 188 indicates that a precision comparable to or slightly better than that of conventional iris photometry or other methods of PDS reduction may easily be attained. Possibilities for the future elaboration of the technique are mentioned.

  4. Detection of Terrestrial Planets Using Transit Photometry

    NASA Technical Reports Server (NTRS)

    Koch, David; Witteborn, Fred; Jenkins, Jon; Dunham, Edward; Boruci, William; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Transit photometry detection of planets offers many advantages: an ability to detect terrestrial size planets, direct determination of the planet's size, applicability to all main-sequence stars, and a differential brightness change of the periodic signature being independent of stellar distance or planetary orbital semi-major axis. Ground and space based photometry have already been successful in detecting transits of the giant planet HD209458b. However, photometry 100 times better is required to detect terrestrial planets. We present results of laboratory measurements of an end-to-end photometric system incorporating all of the important confounding noise features of both the sky and a space based photometer including spacecraft jitter. In addition to demonstrating an instrumental noise of less than 10 ppm (an Earth transit of a solar-like star is 80 ppm), the brightnesses of individual stars were dimmed to simulate Earth-size transit signals. These 'transits' were reliably detected as part of the tests.

  5. Photometry Studies of Asteroids and Variable Stars

    NASA Astrophysics Data System (ADS)

    Han, Xianming; Li, B.; Zhao, H.; Liu, W.; Sun, L.; Gao, S.; Shi, J.; Wang, S.; Pan, X.; Jiang, P.; Zhou, H.

    2013-01-01

    During the fall semester of 2012, we carried out extensive photometry studies of asteroids to obtain their rotation periods using the 0.9-m SARA North telescope located at the Kitt Peak National Observatory in Arizona and at the 0.6-m SARA South telescope located at the Cerro Tololo Inter-American Observatory in Chile. The asteroids that we carried out photometry studies include: 782 Montefiore, 3024 Hainan, 3842 Harlansmith, 3920 Aubignan, 5542 Moffatt, 5951 AliceMone, 6720 Gifu, 19978 1989VJ. We will present their rotation periods, and compare with previous results where available. During the course of photometry studies, we also discovered several variable stars. We will also present these new variable stars and their periods.

  6. Elucidating Sources and Factors Affecting Delivery of Nitrogen to Surface Waters of New York State

    NASA Astrophysics Data System (ADS)

    Golden, H. E.; Boyer, E. W.; Burns, D. A.; Elliott, E.; Kendall, C.; Butler, T.

    2005-12-01

    Rapid changes in power generation, transportation, and agriculture have appreciably altered nitrogen (N) cycling at regional scales, increasing N inputs to landscapes and surface waters. Numerous studies have linked this surplus N to a host of concerns, including eutrophication and violations in drinking water standards. Inputs of N nation-wide have increased during recent decades, primarily from the production and use of fertilizers, the planting of N-fixing crops, and the combustion of fossil fuels. The role of atmospheric N sources is of particular concern in New York, as rates of atmospheric N deposition in the northeast are among the highest in the nation. Our work aims to quantify nitrogen sources and fate in watersheds throughout the state. Further, we intend to elucidate factors controlling the retention and release of N to surface waters. We quantify nitrogen inputs through both measurement data (e.g., from wet and dry atmospheric deposition, precipitation, streamflow, water quality, and isotopic tracers) and from synoptic spatial databases (e.g., of terrain, land use, and fertilizer inputs). We present preliminary results from large catchments in contrasting spatial settings across the state (different land use configurations and atmospheric deposition gradients), illustrating the contribution of nitrogen sources to each region and factors affecting delivery to surface waters. Further, we present 30 years of temporal data from a large watershed (Fall Creek) in the Finger Lakes region of the state to demonstrate how hydrological and biogeochemical factors, over seasons and under varying hydrological regimes, combine to control N dynamics in surface waters. Our collective work provides information that is necessary to develop sound strategies for understanding and managing nutrients at regional scales.

  7. Surface coating affects behavior of metallic nanoparticles in a biological environment

    PubMed Central

    Jurašin, Darija Domazet; Ćurlin, Marija; Capjak, Ivona; Crnković, Tea; Lovrić, Marija; Babič, Michal; Horák, Daniel; Gajović, Srećko

    2016-01-01

    Summary Silver (AgNPs) and maghemite, i.e., superparamagnetic iron oxide nanoparticles (SPIONs) are promising candidates for new medical applications, which implies the need for strict information regarding their physicochemical characteristics and behavior in a biological environment. The currently developed AgNPs and SPIONs encompass a myriad of sizes and surface coatings, which affect NPs properties and may improve their biocompatibility. This study is aimed to evaluate the effects of surface coating on colloidal stability and behavior of AgNPs and SPIONs in modelled biological environments using dynamic and electrophoretic light scattering techniques, as well as transmission electron microscopy to visualize the behavior of the NP. Three dispersion media were investigated: ultrapure water (UW), biological cell culture medium without addition of protein (BM), and BM supplemented with common serum protein (BMP). The obtained results showed that different coating agents on AgNPs and SPIONs produced different stabilities in the same biological media. The combination of negative charge and high adsorption strength of coating agents proved to be important for achieving good stability of metallic NPs in electrolyte-rich fluids. Most importantly, the presence of proteins provided colloidal stabilization to metallic NPs in biological fluids regardless of their chemical composition, surface structure and surface charge. In addition, an assessment of AgNP and SPION behavior in real biological fluids, rat whole blood (WhBl) and blood plasma (BlPl), revealed that the composition of a biological medium is crucial for the colloidal stability and type of metallic NP transformation. Our results highlight the importance of physicochemical characterization and stability evaluation of metallic NPs in a variety of biological systems including as many NP properties as possible. PMID:26977382

  8. Surface coating affects behavior of metallic nanoparticles in a biological environment.

    PubMed

    Jurašin, Darija Domazet; Ćurlin, Marija; Capjak, Ivona; Crnković, Tea; Lovrić, Marija; Babič, Michal; Horák, Daniel; Vinković Vrček, Ivana; Gajović, Srećko

    2016-01-01

    Silver (AgNPs) and maghemite, i.e., superparamagnetic iron oxide nanoparticles (SPIONs) are promising candidates for new medical applications, which implies the need for strict information regarding their physicochemical characteristics and behavior in a biological environment. The currently developed AgNPs and SPIONs encompass a myriad of sizes and surface coatings, which affect NPs properties and may improve their biocompatibility. This study is aimed to evaluate the effects of surface coating on colloidal stability and behavior of AgNPs and SPIONs in modelled biological environments using dynamic and electrophoretic light scattering techniques, as well as transmission electron microscopy to visualize the behavior of the NP. Three dispersion media were investigated: ultrapure water (UW), biological cell culture medium without addition of protein (BM), and BM supplemented with common serum protein (BMP). The obtained results showed that different coating agents on AgNPs and SPIONs produced different stabilities in the same biological media. The combination of negative charge and high adsorption strength of coating agents proved to be important for achieving good stability of metallic NPs in electrolyte-rich fluids. Most importantly, the presence of proteins provided colloidal stabilization to metallic NPs in biological fluids regardless of their chemical composition, surface structure and surface charge. In addition, an assessment of AgNP and SPION behavior in real biological fluids, rat whole blood (WhBl) and blood plasma (BlPl), revealed that the composition of a biological medium is crucial for the colloidal stability and type of metallic NP transformation. Our results highlight the importance of physicochemical characterization and stability evaluation of metallic NPs in a variety of biological systems including as many NP properties as possible. PMID:26977382

  9. Light-induced heterogeneous reactions of NO2 on indoor surfaces: How they affect the balance of nitrous acid

    NASA Astrophysics Data System (ADS)

    Gomez Alvarez, E.; Soergel, M.; Bassil, S.; Zetzsch, C.; Gligorovski, S.; Wortham, H.

    2011-12-01

    Nitrous acid (HONO) is an important indoor pollutant. The adverse health effects due to the formation of nitrosamines are well known. HONO acts as a nitrosating agent after wall reactions of HONO with nicotine [Sleiman et al., 2010]. Indoor air can be surprisingly rich in HONO (homes with fireplaces, stoves, gas heating and cooking) and also surfaces are abundant. High HONO concentrations have been measured in indoor environments, from the direct emissions and heterogeneous reactions of NO2 in darkness. However, the measured HONO concentrations do not correspond to the HONO levels determined by the models [Carslaw, 2007]. We have tested in a flow tube reactor on-line coupled to a NOx analyzer and a sensitive Long Path Absorption Photometry instrument, the behaviour of various indoor surfaces towards NO2 under simulated solar light irradiation (λ= 300-700 nm). Our study has allowed us to obtain a deeper knowledge on the mechanisms of heterogeneous formation of HONO, quantifying the dependence of HONO formation on behalf of NO2 concentration and relative humidity and the enhancement of HONO formation in the presence of light. Pyrex, acidic detergent, alkaline detergent, paint and lacquer were tested on behalf of their heterogeneous reactivity towards NO2 in the absence and in presence of light. The results obtained demonstrated that indoor surfaces are photo-chemically active under atmospherically relevant conditions. The strongly alkaline surfaces (such as certain types of detergent) show a strong long-term uptake capacity. However, other surfaces such as detergents with a more acidic character released HONO. In some cases such as paint and varnish, a strong HONO release with light was detected, which was significantly higher than that obtained over clean glass surfaces. Certain organics present on their composition could exert a photo-sensitizing effect that may explain their increased reactivity. Unfortunately, the final balance points towards an important net production of HONO from organics usually applied on different indoor surfaces that add to the very powerful HONO production simply due to heterogeneous reactivity on bare indoor surfaces. The results of this study add to the increasing concern over the reactivity in indoor environments and in particular from the point of view of HONO formation kinetics.

  10. Photometry of the old nova HZ Pup

    NASA Astrophysics Data System (ADS)

    Cassanelli, Tomas; Abbott, Tim

    2016-01-01

    This study of the old nova HZ Pup involved obtaining image data, removing the instrumental signature, performing photometry on the stellar images present, and generating light curves. Relative photometry between the target star and other stars in the image was used to remove atmospheric effects. A periodogram of this light curve shows the historically known periodicity close to 20 minutes. However, other periodicities are also present and it is not clear from the data which are real and which are artifacts of the sampling. These data will be combined with data from other telescopes collected contemporaneously in order to resolve this ambiguity.

  11. Soil factors affecting mycorrhizal use in surface mine reclamation. Information circular/1993

    SciTech Connect

    Norland, M.R.

    1993-01-01

    Surface and subsurface stabilization of mining-related wastes through revegetation depends upon the physical, chemical, and biological condition of the waste following mining. Mining disturbances can significantly alter the soil physical, chemical, and biological characteristics of a site, reducing or eliminating mycorrhizal fungi from the soil. Mycorrhizae are economically and ecologically important because they can alleviate environmental stresses caused by lack of proper soil condition and because they are vital to stabilization of mining waste by increasing plant survival and biomass through increased nutrient and water uptake. The report discusses some of the ecological factors that may affect mycorrhizae-plant associations on mining-related wastes and provides general information on mycorrhizae inoculation technology.

  12. Multiband Photometry of the Chromospherically Active & Spotted Binary System IM Peg—the Guide Star for the Gravity Probe B Mission

    NASA Astrophysics Data System (ADS)

    Zellem, Robert; Guinan, Edward F.; Messina, Sergio; Lanza, Antonino F.; Wasatonic, Richard; McCook, George P.

    2010-06-01

    We report on the starspot properties of IM Pegasi—the guide star of the Gravity Probe B (GP-B) satellite. GP-B's mission is to measure two predicted consequences of general relativity—the frame-dragging and geodetic effects—via its extremely precise onboard gyroscopes. However, IM Peg is a chomospherically active binary system with a luminous K2 III primary star showing rotationally modulated (Prot ≈ 24.5 days) light variations from starspots. The starspots can potentially cause problems as GP-B can erroneously interpret a change in starspot coverage (and corresponding shifts in the light center) as the star's movement. This apparent shift can also be exacerbated by possible changes in the light center (photocenter) of the binary system arising from changes in the light balance with the fainter ~1 Msolar (main-sequence early G-type star) component. Since 2000, we have carried out multiband high-precision photoelectric photometry of IM Peg to determine its activity and starspot coverage. Our photometry uses Strömgren uvby intermediate-band filters, VRI filters, and TiO (720/750 nm) narrowband filter sets. Measurements were made relative to nearby comparison and check stars using 0.8 m and 0.25 m telescopes. Analysis of TiO and multiband continuum photometry constrains the starspot areas, temperatures, and surface distributions. The photometry has been modeled using the maximum entropy and Tikhonov regularizations to determine the properties of starspots and to evaluate the effects of changing starspot areas and distributions on the light center of the binary. Our results indicate that IM Peg's activity should not affect the GP-B mission. We also present a study of IM Peg's long-term starspot cycle, which shows evidence of being 20 yr long. Lastly, we have determined the intrinsic (unspotted) brightness of the star to be V mag = 5.62 ± 0.03.

  13. Mendelian and non-mendelian mutations affecting surface antigen expression in Paramecium tetraurelia

    SciTech Connect

    Epstein, L.M.; Forney, J.D.

    1984-08-01

    A screening procedure was devised for the isolation of X-ray-induced mutations affecting the expression of the A immobilization antigen (i-antigen) in Paramecium tetraurelia. Two of the mutations isolated by this procedure proved to be in modifier genes. The two genes are unlinked to each other and unlinked to the structural A i-antigen gene. These are the first modifier genes identified in a Paramecium sp. that affect surface antigen expression. Another mutation was found to be a deletion of sequences just downstream from the A i-antigen gene. In cells carrying this mutation, the A i-antigen gene lies in close proximity to the end of a macronuclear chromosome. The expression of the A i-antigen is not affected in these cells, demonstrating that downstream sequences are not important for the regulation and expression of the A i-antigen gene. A stable cell line was also recovered which shows non-Mendelian inheritance of a macronuclear deletion of the A i-antigen gene. This mutant does not contain the gene in its macronucleus, but contains a complete copy of the gene in its micronucleus. In the cytoplasm of wild-type animals, the micronuclear gene is included in the developing macronucleus; in the cytoplasm of the mutant, the incorporation of the A i-antigen gene into the macronucleus is inhibited. This is the first evidence that a mechanism is available in ciliates to control the expression of a gene by regulating its incorporation into developing macronuclei.

  14. Factors affecting the stimulus artifact tail in surface-recorded somatosensory-evoked potentials.

    PubMed

    Hua, Y; Lovely, D F; Doraiswami, R

    2006-03-01

    Surface-recorded somatosensory-evoked potentials (SEPs) are neural signals elicited by an external stimulus. In the case of electrically induced SEPs, the artifact generated by the stimulation process can severely distort the signal. In some cases, the artifact tail often lasts well into the initiation of the SEP making the determination of absolute latency very difficult. In this work, a new approach was taken to identify factors that affect the tail of the artifact. The methodology adopted was the development of a lumped electrical circuit model of the artifact generation process. While the modeling of the instrumentation hardware is relatively simple, this is not the case with tissue and electrode/skin interface effects. Consequently, this paper describes a novel tissue modeling approach that uses an autoregressive moving average (ARMA) parametric technique and an artificial neural network (ANN) to estimate tissue parameters from experimental data. This coupled with an estimation of the stimulation electrode-skin impedance completes the lumped circuit model. Simulink (The Mathworks Inc.) was used to evaluate the model under several different conditions. These results show that both the stimulation electrode-skin interface impedance and nature of the body tissue directly under the recording electrodes have a profound effect on the appearance of the stimulus artifact tail. This was verified by experimentally recorded data obtained from the median nerve using surface electrodes. Conclusions drawn from this work include that stimulation electrodes with low series capacitance should be used whenever possible to minimize the duration of the artifact tail. PMID:16937164

  15. Inferring planetary obliquity using rotational and orbital photometry

    NASA Astrophysics Data System (ADS)

    Schwartz, J. C.; Sekowski, C.; Haggard, H. M.; Pallé, E.; Cowan, N. B.

    2016-03-01

    The obliquity of a terrestrial planet is an important clue about its formation and critical to its climate. Previous studies using simulated photometry of Earth show that continuous observations over most of a planet's orbit can be inverted to infer obliquity. However, few studies of more general planets with arbitrary albedo markings have been made and, in particular, a simple theoretical understanding of why it is possible to extract obliquity from light curves is missing. Reflected light seen by a distant observer is the product of a planet's albedo map, its host star's illumination, and the visibility of different regions. It is useful to treat the product of illumination and visibility as the kernel of a convolution. Time-resolved photometry constrains both the albedo map and the kernel, the latter of which sweeps over the planet due to rotational and orbital motion. The kernel's movement distinguishes prograde from retrograde rotation for planets with non-zero obliquity on inclined orbits. We demonstrate that the kernel's longitudinal width and mean latitude are distinct functions of obliquity and axial orientation. Notably, we find that a planet's spin axis affects the kernel - and hence time-resolved photometry - even if this planet is east-west uniform or spinning rapidly, or if it is north-south uniform. We find that perfect knowledge of the kernel at 2-4 orbital phases is usually sufficient to uniquely determine a planet's spin axis. Surprisingly, we predict that east-west albedo contrast is more useful for constraining obliquity than north-south contrast.

  16. TRIPP: Time Resolved Imaging Photometry Package

    NASA Astrophysics Data System (ADS)

    Geckeler, Ralf D.; Schuh, Sonja; Dreizler, Stefan; Deetjen, Jochen; Gleissner, Thomas; Risse, Patrick; Rauch, Thomas; Göhler, Eckart; Hügelmeyer, Simon; Husser, Tim-Oliver; Israel, Holger; Benlloch-Garcia, Sara; Pottschmidt, Katja; Wilms, Jörn

    2014-05-01

    Written in IDL, TRIPP performs CCD time series reduction and analysis. It provides an on-line check of the incoming frames, performs relative aperture photometry and provides a set of time series tools, such as calculation of periodograms including false alarm probability determination, epoc folding, sinus fitting, and light curve simulations.

  17. Detecting Problematic Observer Offsets in Sparse Photometry

    NASA Astrophysics Data System (ADS)

    Calderwood, T.

    2014-06-01

    A heuristic method, based upon histogram analysis, is presented for detecting offsets pervasive enough to be symptoms of problematic observing technique or calibration. This method is illustrated by a study of scatter in AAVSO photoelectric photometry (PEP) for five well-observed variable stars.

  18. Detecting Problematic Observer Offsets in Sparse Photometry

    NASA Astrophysics Data System (ADS)

    Calderwood, Tom

    2014-05-01

    A heuristic method, based upon histogram analysis, is presented for detecting offsets pervasive enough to be symptoms of problematic observing technique or calibration. This method is illustrated by a study of scatter in AAVSO photoelectric photometry (PEP) for five well-observed variable stars.

  19. Photometry of Faint Wide Doubles in Hydra

    NASA Astrophysics Data System (ADS)

    Knapp, Wilfried; Thuemen, Chris; Gould, Ross

    2015-11-01

    Images of several double stars in Hydra published on the "Double Star Imaging Project" Yahoo Group page suggest magnitude issues compared with the corresponding WDS catalog data per end of 2014. Taking additional images with V and B filters enabled photometry for these pairs, suggesting significant corrections to the old data in WDS.

  20. ATel 7543: NIR photometry of SNhunt 275

    NASA Astrophysics Data System (ADS)

    Richardson, Noel; Artigau, Etienne

    2015-05-01

    SNhunt 275 (PSN J09093496+3307204) appears to be behaving similarly to SN 2009ip with an eruptive mass-loss event followed by a supernova explosion. We obtained a few epochs of NIR photometry using the Observatoire du Mont Megantic 1.6 m telescope and the CPAPIR instrument (Artigau et al. ...

  1. Photoelectric photometry era at the Astronomical Institute of the Slovak Academy of Sciences III. Fast photometry

    NASA Astrophysics Data System (ADS)

    Vaňko, M.; Kollár, V.; Komžík, R.; Koza, J.; Pribulla, T.

    2015-12-01

    We present a continuation of the article series describing the photoelectric photometry era at the Astronomical Institute of the Slovak Academy of Sciences. The paper aims to provide a comprehensive technical description of implementation of the fast photometry at the Stará Lesná Observatory and estimates its photometric precision. Using integration times of 0.1 s and 0.01 s, an estimated photometric precision of the fast photometry is about 0.02 mag and 0.06 mag, respectively. Here, we also show the observation principles of the fast photometry and its use in positive observation of stellar occultation lasting 18.44 s by the asteroid (85) Io.

  2. Precision Multiband Photometry with a DSLR Camera

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Bakos, G. Á.; Penev, K.; Csubry, Z.; Hartman, J. D.; Bhatti, W.; de Val-Borro, M.

    2016-03-01

    Ground-based exoplanet surveys such as SuperWASP, HAT Network of Telescopes (HATNet), and KELT have discovered close to two hundred transiting extrasolar planets in the past several years. The strategy of these surveys is to look at a large field of view and measure the brightnesses of its bright stars to around half a percent per point precision, which is adequate for detecting hot Jupiters. Typically, these surveys use CCD detectors to achieve high precision photometry. These CCDS, however, are expensive relative to other consumer-grade optical imaging devices, such as digital single-lens reflex cameras (DSLRs). We look at the possibility of using a DSLR camera for precision photometry. Specifically, we used a Canon EOS 60D camera that records light in three colors simultaneously. The DSLR was integrated into the HATNet survey and collected observations for a month, after which photometry was extracted for 6600 stars in a selected stellar field. We found that the DSLR achieves a best-case median absolute deviation of 4.6 mmag per 180 s exposure when the DSLR color channels are combined, and 1000 stars are measured to better than 10 mmag (1%). Also, we achieve 10 mmag or better photometry in the individual colors. This is good enough to detect transiting hot Jupiters. We performed a candidate search on all stars and found four candidates, one of which is KELT-3b, the only known transiting hot Jupiter in our selected field. We conclude that the Canon 60D is a cheap, lightweight device capable of useful photometry in multiple colors.

  3. The NGC 1399 Globular Cluster System: Washington Photometry Revisited

    NASA Astrophysics Data System (ADS)

    Ostrov, Pablo G.; Forte, Juan C.; Geisler, Doug

    1998-12-01

    A new analysis and discussion of Washington CCD photometry for some 500 globular cluster candidates associated with the Fornax cluster cD galaxy NGC 1399 are presented. The image handling in this work includes improved methods for the removal of both the galaxy halo and fringing effects over that employed in a previous work of ours. The analysis of the globular cluster candidates inside an annular region between 0.5‧ and 4' from the galaxy center using two-color diagrams shows a clear bimodal distribution for objects fainter than T_1 = 21.0 (V ~ 21.5). The modal colors of the globular clusters belonging to the red population are coincident, within the measuring uncertainties, with those of the galaxy halo. In turn, the average integrated colors of the blue population are comparable to those of the bluest non-star-forming low surface brightness galaxies in Fornax. Red clusters appear more centrally concentrated than the blue clusters. A new determination of the integrated luminosity function turnover (T_1 = 23.24) leads to a distance modulus for NGC 1399 of V_0 - M_V = 31.02 +/- 0.2. The total number of globular clusters, combined with our preliminary photometry of the galaxy halo, leads to an overall specific frequency S_N = 5.6 +/- 1.0, which is considerably lower than previous estimates available in the literature. We note that these last values have been based on an extrapolation of aperture photometry of the inner regions of the galaxy.

  4. Infrared Photometry for Automated Telescopes: Passband Selection

    NASA Astrophysics Data System (ADS)

    Milone, Gene; Young, Andrew T.

    2011-03-01

    The high precision that photometry in the near and intermediate infrared region can provide has not been achieved, partly because of technical challenges (including cryogenics, which most IR detectors require), and partly because the filters in common use are not optimized to avoid water-vapor absorptions, which are the principal impediment to precise ground-based IR photometry. We review the IRWG filters that achieve this goal, and the trials that were undertaken to demonstrate their superiority. We focus especially on the near IR set and, for high elevation sites, the passbands in the N window. We also discuss the price to be paid for the improved precision, in the form of lower throughput, and why it should be paid: to achieve not only higher precision (i.e., improved signal-to-noise ratio), but also lower extinction, thus producing higher accuracy in extra-atmospheric magnitudes. The edges of the IRWG passbands are not defined by the edges of the atmospheric windows: therefore, they admit no flux from these (constantly varying) edges. The throughput cost and the lack of a large body of data already obtained in these passbands are principal reasons why the IRWG filters are not in wide use at observatories around the world that currently do IR work. Yet a measure of the signal-to-noise ratio varies inversely with both extinction and with a measure of the Forbes effect. So, the small loss of raw throughput is recouped in signal-to-noise gain. We illustrate these points with passbands of both near and intermediate IR passbands. There is also the matter of cost for small production runs of these filters; reduced costs can be realized through bulk orders with uniform filter specifications. As a consequence, the near-IR IRWG passbands offer the prospect of being able to do photometry in those passbands at both high and low elevation sites that are capable of supporting precise photometry, thereby freeing infrared photometry from the need to access exclusively high and dry elevation sites, although photometry done at those sites can also benefit from improved accuracy and transformability. We suggest that if the IRWG passbands are made available, they will be used! New automated systems making use of these passbands have the advantage of establishing the system more widely, creating a larger body of data to which future observations will be fully transformable, and will be cheaper to purchase. This work has been supported in part by grants to EFM by the Canadian Natural Sciences and Engineering Research Council.

  5. Deep photometry and integral magnitudes of 8 nearby galaxies

    NASA Astrophysics Data System (ADS)

    Georgiev, Ts. B.

    2016-02-01

    We estimated integral magnitudes of galaxies trying to include the contribution of the brightest part of their halos. We performed surface photometry based on (i) concentric elliptical rims, corresponding to the peripheral ellipticity of the image, (ii) median estimation of the mean value of the rim pixels, (iii) apparent radial brightness profiles, corresponding to the rim medians, and (iv) magnitude curves of growth, derived by numerical integrations of the apparent rim profiles, without preliminary background estimation and removal. Furthermore, we used the magnitude curves of growth to determine the integral magnitudes (limited by size and deepness of our frames) and compared them with the total magnitudes in the data base HyperLeda. Also, we used the rim-profiles to estimate the background level far enough from the galaxy center and we build (here—only for trial) the intrinsic radial profiles (with background removal). We apply this photometry on 8 nearby galaxies, observed with CCD in the system BVRC IC by the 50 cm Schmidt telescope of the Rozhen NAO in 2003-2004. We build radial profiles which occur to be as average 1.8 times (1.2-2.5 times) larger than in data base NED and of integral brightness that occurs to be about 1.4 times (1.2-1.7 times) higher than in data base HyperLeda. The relative brightness additions, found here, correlate with the color index and anti-correlate with the luminosity of the galaxy.

  6. Surface Physicochemistry and Ionic Strength Affects eDNA’s Role in Bacterial Adhesion to Abiotic Surfaces

    PubMed Central

    Regina, Viduthalai R.; Lokanathan, Arcot R.; Modrzyński, Jakub J.; Sutherland, Duncan S.; Meyer, Rikke L.

    2014-01-01

    Extracellular DNA (eDNA) is an important structural component of biofilms formed by many bacteria, but few reports have focused on its role in initial cell adhesion. The aim of this study was to investigate the role of eDNA in bacterial adhesion to abiotic surfaces, and determine to which extent eDNA-mediated adhesion depends on the physicochemical properties of the surface and surrounding liquid. We investigated eDNA alteration of cell surface hydrophobicity and zeta potential, and subsequently quantified the effect of eDNA on the adhesion of Staphylococcus xylosus to glass surfaces functionalised with different chemistries resulting in variable hydrophobicity and charge. Cell adhesion experiments were carried out at three different ionic strengths. Removal of eDNA from S. xylosus cells by DNase treatment did not alter the zeta potential, but rendered the cells more hydrophilic. DNase treatment impaired adhesion of cells to glass surfaces, but the adhesive properties of S. xylosus were regained within 30 minutes if DNase was not continuously present, implying a continuous release of eDNA in the culture. Removal of eDNA lowered the adhesion of S. xylosus to all surfaces chemistries tested, but not at all ionic strengths. No effect was seen on glass surfaces and carboxyl-functionalised surfaces at high ionic strength, and a reverse effect occurred on amine-functionalised surfaces at low ionic strength. However, eDNA promoted adhesion of cells to hydrophobic surfaces irrespective of the ionic strength. The adhesive properties of eDNA in mediating initial adhesion of S. xylosus is thus highly versatile, but also dependent on the physicochemical properties of the surface and ionic strength of the surrounding medium. PMID:25122477

  7. CCD Photometry of the Polar BY Cam

    NASA Astrophysics Data System (ADS)

    Jessop, H.; Chin, V.; Spear, G.

    1992-12-01

    BY Cam (=H0538+608), a very erratic member of the AM Herculis-type binaries also known as polars, was observed at the University of Arizona 40-inch telescope, with the Sonoma State University Astrolink CCD camera for six nights during November 1991. Two additional nights of CCD photometry were obtained during September 1992 at the Sonoma State Observatory, with the 25-cm Epoch Automated Telescope and SSU Astrolink CCD camera. These data comprise one of the most extensive sets of photometry acquired for this object. We will present the results of these observations, and discuss their relevance towards the further determination of some of the system's parameters. This work has been supported by a California State University Pre-Doctoral Award and Pre-Doctoral Summer Internship Award, and a Grant-In-Aid from the Sigma Xi Scientific Research Society.

  8. UBV photometry of hot white dwarf stars

    NASA Astrophysics Data System (ADS)

    Cheselka, Mathew; Holberg, J. B.; Watkins, Ron; Collins, James; Tweedy, R. W.

    1993-12-01

    Johnson UBV photometry has been obtained for a set of hot degenerate stars, primarily DA and DO white dwarfs from among those detected in the Palomar-Green survey of UV excess objects. Most of our program stars have estimated effective temperatures (Teff) in the range 22,000 to 80,000 K and have no previous photometry. Some objects selected are also x-ray and extreme ultraviolet sources from the ROSAT all sky survey. The importance of precise photometric measurements in the analysis of x-ray data is discussed. A discrepancy between the observed colors and predicted colors is noted, and possibly accounted for by difficulties in defining the atmospheric cutoff of the U band and a general lack of hot stars used to define the photometric transformation between theoretical and observed colors.

  9. Recalibrating SFD Using SDSS Spectroscopy And Photometry

    NASA Astrophysics Data System (ADS)

    Schlafly, Eddie; Finkbeiner, D. P.

    2011-05-01

    We use new measurements of reddening using SDSS photometry and spectroscopy to test the SFD dust map. We find that both the photometric and spectroscopic technique agree on a common SFD calibration that is different from the original SFD calibration by 13%. We find additionally that a Fitzpatrick 1999 reddening law provides a good fit to the reddening law derived from these techniques, while CCM and O'Donnell reddening laws are disfavored.

  10. Photometry of Saturn at large phase angles

    NASA Technical Reports Server (NTRS)

    Tomasko, M. G.; Mcmillan, R. S.; Doose, L. R.; Castillo, N. D.; Dilley, J. P.

    1980-01-01

    In the present paper, the single-scattering phase function of Saturn's aerosols is determined from the vertical structure of Saturn's atmosphere, derived in a previous analysis, and Pioneer's imaging photometry of bright and dark zones on Saturn in red and blue light. The single-scattering phase function is well represented by a combination of two Henyey-Greenstein functions. Moderately forward scattering functions fit well both in red and blue light, although a definite difference between the two colors is found.

  11. WISE Photometry for 400 Million SDSS Sources

    NASA Astrophysics Data System (ADS)

    Lang, Dustin; Hogg, David W.; Schlegel, David J.

    2016-02-01

    We present photometry of images from the Wide-Field Infrared Survey Explorer (WISE) of over 400 million sources detected by the Sloan Digital Sky Survey (SDSS). We use a “forced photometry” technique, using measured SDSS source positions, star-galaxy classification, and galaxy profiles to define the sources whose fluxes are to be measured in the WISE images. We perform photometry with The Tractor image modeling code, working on our “unWISE” coaddds and taking account of the WISE point-spread function and a noise model. The result is a measurement of the flux of each SDSS source in each WISE band. Many sources have little flux in the WISE bands, so often the measurements we report are consistent with zero given our uncertainties. However, for many sources we get 3σ or 4σ measurements; these sources would not be reported by the “official” WISE pipeline and will not appear in the WISE catalog, yet they can be highly informative for some scientific questions. In addition, these small-signal measurements can be used in stacking analyses at the catalog level. The forced photometry approach has the advantage that we measure a consistent set of sources between SDSS and WISE, taking advantage of the resolution and depth of the SDSS images to interpret the WISE images; objects that are resolved in SDSS but blended together in WISE still have accurate measurements in our photometry. Our results, and the code used to produce them, are publicly available at http://unwise.me.

  12. Lightcurve Photometry Opportunities: 2016 April-June

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Harris, Alan W.; Durech, Josef; Benner, Lance A. M.

    2016-04-01

    We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and having either none or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.

  13. Lightcurve Photometry Opportunities: 2016 January-March

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Harris, Alan W.; Durech, Josef; Benner, Lance A. M.

    2016-01-01

    We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and have no or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.

  14. Galileo Photometry of Asteroid 951 Gaspra

    USGS Publications Warehouse

    Helfenstein, P.; Veverka, J.; Thomas, P.C.; Simonelli, D.P.; Lee, P.; Klaasen, K.; Johnson, T.V.; Breneman, H.; Head, J.W.; Murchie, S.; Fanale, F.; Robinson, M.; Clark, B.; Granahan, J.; Garbeil, H.; McEwen, A.S.; Kirk, R.L.; Davies, M.; Neukum, G.; Mottola, S.; Wagner, R.; Belton, M.; Chapman, C.; Pilcher, C.

    1994-01-01

    Galileo images of Gaspra make it possible for the first time to determine a main-belt asteroid's photometric properties accurately by providing surface-resolved coverage over a wide range of incidence and emission angles and by extending the phase angle coverage to phases not observable from Earth. We combine Earth-based telescopic photometry over phase angles 2?? ??? ?? ??? 25?? with Galileo whole-disk and disk-resolved data at 33?? ??? ?? ??? 51?? to derive average global photometric properties in terms of Hapke's photometric model. The microscopic texture and particle phase-function behavior of Gaspra's surface are remarkably like those of other airless rocky bodies such as the Moon. The macroscopic surface roughness parameter, ??̄ = 29??, is slightly larger than that reported for typical lunar materials. The particle single scattering albedo, ??́0 = 0.36 ?? 0.07, is significantly larger than for lunar materials, and the opposition surge amplitude, B0 = 1.63 ?? 0.07, is correspondingly smaller. We determine a visual geometric albedo pv = 0.22 ?? 0.06 for Gaspra, in close agreement with pv = 0.22 ?? 0.03 estimated from Earth-based observations. Gaspra's phase integral is 0.47, and the bolometric Bond albedo is estimated to be 0.12 ?? 0.03. An albedo map derived by correcting Galileo images with our average global photometric function reveals subdued albedo contrasts of ??10% or less over Gaspra's northern hemisphere. Several independent classification algorithms confirm the subtle spectral heterogeneity reported earlier (S. Mottola, M. DiMartino, M. Gonano-Beurer, H. Hoffman, and G. Neukum, 1993, Asteroids, Comets, Meteors, pp. 421-424; M. J. S. Belton et al., 1992, Science 257, 1647-1652). Whole-disk colors (0.41 ??? ?? ??? 0.99 ??m) vary systematically with longitude by about ??5%, but color differences as large as 30% occur locally. Colors vary continuously between end-member materials whose areal distribution correlates with regional topography. Infrared: violet (0.99:0.41-??m) color ratios on Gaspra are strongly correlated with local elevation, being largest at lower elevations and smaller at higher elevations. No correlation was detected between elevation and the green:violet (0.56:0.41-??m) color ratio. Bright materials with a strong 1-??m absorption occur primarily in association with craters along ridges, while darker materials with 30% weaker 1-??m signatures occur downslope. The variations of color and albedo cannot be easily explained by grain-size effects alone or by differences in photometric geometry. The trends observed are consistent with those revealed by laboratory studies of the effects of comminution, glass formation, and segregation of metal from silicate components in chondritic meteorites and also in some silicate mixtures. The relative importance of these various processes on Gaspra remains to be determined. ?? 1994 Academic Press. All rights reserved.

  15. Marine organic geochemistry in industrially affected coastal areas in Greece: Hydrocarbons in surface sediments

    NASA Astrophysics Data System (ADS)

    Hatzianestis, Ioannis

    2015-04-01

    Hydrocarbons are abundant components of the organic material in coastal zones. Their sources are mainly anthropogenic, but several natural ones have also been recognized. Among hydrocarbons, the polycyclic aromatic ones (PAHs) have received special attention since they considered as hazardous environmental chemicals and are included in priority pollutant lists. The purpose of this study was to investigate the distribution, sources and transport pathways of hydrocarbons in marine areas in Greece directly influenced from the operation of major industrial units in the coastal zone by using a molecular marker approach, characteristic compositional patterns and related indices and also to evaluate their potential toxicity. Thirty two surface sediment samples were collected from three marine areas: a) Antikyra bay in Korinthiakos gulf, affected from the operation of an alumina and production plant b) Larymna bay in Noth Evoikos, affected from the operation of a nickel production plant and c) Aliveri bay in South Evoikos Gulf, affected from a cement production plant. In all the studied areas aquaculture and fishing activities have been also developed in the coastal zone. High aliphatic hydrocarbon (AHC) concentrations (~500 μg/g), indicating significant petroleum related inputs, were measured only in Antikyra bay. In all the other samples, AHC values were below 100 μg/g. N-alkanes were the most prominent resolved components (R) with an elevated odd to even carbon number preference, revealing the high importance of terrestrial inputs in the study areas. The unresolved complex mixture (UCM) was the major component of the aliphatic fraction (UCM/R > 4), indicating a chronic oil pollution. A series of hopanes were also identified, with patterns characteristic of oil-derived hydrocarbons, further confirming the presence of pollutant inputs from fossil fuel products. Extremely high PAH concentrations (> 100,000 ng/g) were found in the close vicinity of the alumina production plant in Antikyra bay. High levels of PAHs up to 22,000 ng/g were also found in Aliveri bay, whereas lower values up to 7500 ng/g, but still indicating significant pollution, were measured close to the nickel production plant in Larymna bay. The examination of PAH molecular indices revealed that in Antikyra and Larymna bays more than 80% of the PAHs have pyrolytic origin coming from various combustion sources. On the contrary, in Aliveri bay about 60% of the PAHs are related to petrogenic/petroleum inputs. With respect to ecotoxicological effects, mean quotient Effect-Range Median (m-ERM) values, higher than 1.5, were calculated in Antikyra bay, indicating a high probability (76%) of toxicity. In Aliveri and Larymna bays the m-ERM values were between 0.11 and 0.5 bay suggesting a lower probability (21%) of toxicity. Overall, the results of our study reveal that high quantities of PAHs produced from land point sources such as the industrial units can enter into small coastal marine areas supporting activities such as aquaculture and fishing. Thus, desirable and permitted uses must be well defined and regulatory frameworks must be established.

  16. 100 years of photometry and radiometry

    NASA Astrophysics Data System (ADS)

    Hardis, Jonathan E.

    2001-06-01

    Measurement of light is an old subject, though the past 100 years have seen significant advances. 100 years ago, photometry - the art and science of measuring light as it is perceived by people - had the greater technological importance. Even today SI (the metric system) retains a base unit for photometry, the candela. However, early work at NBS included pivotal projects in the field of radiometry - the measurement of the physical characteristics of light. These included the validation of Planck's newly-minted theory of blackbody radiation, determining the radiation constants with good accuracy, and the definitive analysis of the spectral responsivity of human vision, so as to relate photometry to radiometry. This latter work has only increased in importance over the past 75 years as the definition of the candela has changed and improved. Today, NIST makes radiometric, and hence photometric measurements, with unprecedented precision. Cryogenic radiometers based on the principle of electrical substitution measure optical flux with uncertainties of 0.02%. Additional facilities enable measurement of spectral responsivity, spectral radiance, and spectral irradiance. Novel detectors, such as light-traps, allow the best accuracy to be transferred from the primary standards to routinely-used instruments and to calibration customers. Filtered detectors are used to realize photometric scales, radiation temperature scales, and other specialized measurements. Indeed, the story of the metrology of light is the story of continuous improvement, both driven by and enabled by advances in technology. We touch upon some of these as a prelude to the other talks in this Conference.

  17. Material characterization by laser speckle photometry

    NASA Astrophysics Data System (ADS)

    Bendjus, Beatrice; Cikalova, Ulana; Schreiber, Juergen

    2012-10-01

    The damage and stress conditions of large industrial components have to be tested continuously. Especially welding processes in the field of coal production demand a nondestructive monitoring of internal stresses under an external load. In a first step, a new optical method, Laser Speckle Photometry was used during laboratory welding experiments under tensile and bending loads at high strength construction steels. Laser Speckle Photometry is a fast and contactless method for measuring spatial-temporal dynamics of speckle field with high temporal resolution after local heat excitation. The thermally induced change in the material structure causes changes in the speckle-field, which is formed by a probing laser. The shift of the speckle-field is analyzed by statistical methods, using correlation functions. The result of processing is the two-dimensional distribution of thermal diffusivity coefficient correlated to porosity, materials strain or hardness [1-3]. Here, the results of the welding experiments under load are presented. It is shown, that the Laser Speckle Photometry is a suitable technique for nondestructive monitoring and characterization of internal material stresses under external load.

  18. Dynamics between fruit cuticles and surface microflora can affect sanitizing methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofilms are communities of microorganisms held together by substances such as polysaccharides which form on surfaces. These communities do not need to be on living tissue but form on any available surface such as rocks in a stream, interior of pipes and on teeth. On surfaces, including fruit, these...

  19. Analysing Thermal Response Test Data Affected by Groundwater Flow and Surface Temperature Change

    NASA Astrophysics Data System (ADS)

    Verdoya, Massimo; Imitazione, Gianmario; Chiozzi, Paolo; Orsi, Marco; Armadillo, Egidio

    2014-05-01

    Tests that record the underground temperature variation due to a constant heat injected into a borehole (or extracted from it) by means of a carrier fluid are routinely performed to infer subsurface thermal conductivity and borehole thermal resistance, which are needed to size geothermal heat pump systems. The most popular model to analyse temperature-time curves obtained from these tests is the infinite line source (ILS). This model gives appropriate estimations of thermal parameters only if particular hydro-geological conditions are fulfilled. Several flaws can however affect data interpretation with ILS, which is based on strong assumptions like those of a purely conductive heat transfer regime in a homogeneous medium, no vertical heat flow and infinite length of the borehole. Other drawbacks can arise from the difficulty in the proper thermal insulation of the test equipment, and consequently with oscillations of the carrier fluid temperature due to surface temperature changes. In this paper, we focused on the treatment of thermal response test data when both advection and periodic changes of surface temperature occur. We used a moving line source model to simulate temperature-time signals under different hypothesis of Darcy velocity and thermal properties. A random noise was added to the signal in order to mimic high frequency disturbances, possibly caused by equipment operating conditions and/or geological variability. The subsurface thermal conductivity, the Darcy velocity and the borehole thermal resistance were inferred by minimising the root mean square error between the synthetic dataset and the theoretical model. The optimisation was carried out with the Nelder-Mead algorithm, and thermal and hydraulic properties were determined by iterative reprocessing according to a trial-and-error procedure. The inferred thermal and hydraulic parameters are well consistent with the 'a priory' values, and the presence of noise in the synthetic data does not produce instability. The same optimisation procedure was also applied to interpret the synthetic signal with the ILS model. In case of Darcy velocity of the order of 10-6 m s-1, ILS largely overestimates thermal conductivity. The optimisation analysis was then applied to real thermal response tests carried out in boreholes drilled in sedimentary formation aquifers, whose volume heat capacity was assumed to be known. These data showed a periodic offset in the recorded temperature-time series. A Fourier analysis allowed the recognition of harmonic contributions with period of about 12 and 24 hours. These oscillations appeared to be coherent with the data of air temperature change recorded at the test sites. The temperature-time curves were then filtered to remove the disturbing spectral components associated to a non-optimal thermostatic behaviour of the apparatus. This produced reliable estimates of thermal conductivity, Darcy velocity and borehole thermal resistance. The magnitude of the inferred groundwater flow was also checked by means of an independent method based on the analysis of temperature-depth logs recorded prior to the thermal tests, under thermal equilibrium conditions.

  20. Photometry of AM Herculis - A slow optical pulsar

    NASA Technical Reports Server (NTRS)

    Priedhorsky, W. C.; Krzeminski, W.

    1978-01-01

    Multicolor photometry of the X-ray binary AM Her suggests that the red component of the optical flux is closely related to the source of optical circular polarization in the system. It is concluded from the periodic modulation of flux in the U through R bands, which is particularly well-defined when plotted as color curves, that the primary and secondary minima are neither eclipses by a secondary star nor eclipses by a hot spot. It is suggested that the primary minimum in the visual light curve is the eclipse of a region of intense optical emission in the magnetic field near the surface of a degenerate dwarf by that dwarf itself.

  1. Photometry and models of eight near-Earth asteroids

    NASA Astrophysics Data System (ADS)

    Kaasalainen, Mikko; Pravec, Petr; Krugly, Yurij N.; Šarounová, Lenka; Torppa, Johanna; Virtanen, Jenni; Kaasalainen, Sanna; Erikson, Anders; Nathues, Andreas; Ďurech, Josef; Wolf, Marek; Lagerros, Johan S. V.; Lindgren, Mats; Lagerkvist, Claes-Ingvar; Koff, Robert; Davies, John; Mann, Rita; Kušnirák, Peter; Gaftonyuk, Ninel M.; Shevchenko, Vasilij G.; Chiorny, Vasilij G.; Belskaya, Irina N.

    2004-01-01

    We present new observations and models of the shapes and rotational states of the eight near-Earth Asteroids (1580) Betulia, (1627) Ivar, (1980) Tezcatlipoca, (2100) Ra-Shalom, (3199) Nefertiti, (3908) Nyx, (4957) Brucemurray, and (5587) 1990 SB. We also outline some of their solar phase curves, corrected to common reference geometry with the models. Some of the targets may feature sizable global nonconvexities, but the observable solar phase angles were not sufficiently high for confirming these. None is likely to have a very densely cratered surface. We discuss the role of the intermediate topographic scale range in photometry, and surmise that this scale range is less important than large or small scale lengths.

  2. Precision photometry and variability of massive stars from space

    NASA Astrophysics Data System (ADS)

    Moffat, Anthony F. J.

    2013-06-01

    While the satellites CoRoT and Kepler, launched in 2007 and 2010, have recently provided long, intense time-series of precision photometric data for a few fairly massive stars, they are limited in sky coverage and are mainly dedicated to asteroseismology of lower-mass stars and transits of exoplanets. On the other hand, the MOST mission has been operating since 2003 and reaches a much larger swath of sky. I will examine what has been done to date in the area of precision time-dependent optical photometry of massive stars, primarily from space. Of particular interest is the MOST photometry of eight bright WR stars of various subtypes: While few if any pulsations have been detected down to a level well below 1 mmag, a new paradigm appears to be emerging: the frequent presence of quasi-periodic, cuspy-like photometric variations in mainly later-type WN and WC stars. This variability (up to several percent) may be related to non-radial pulsations of the underlying star, or more likely, magnetic spots ultimately generated by newly revealed sub-surface convection in hot luminous stars, which may be especially prevalent in deeper surface layers of cooler late-type WR stars. Such localized (hot) spots could also be the drivers of Corotating Interaction Regions linked to rotation of the underlying star. Similar results appear to be forthcoming for O stars as well. The soon-to-be-launched nanosatellite array BRITE-Constellation will concentrate on variability of a large number of naked-eye luminous stars.

  3. Magnetic activity on V889 Herculis. Combining photometry and spectroscopy

    NASA Astrophysics Data System (ADS)

    Järvinen, S. P.; Korhonen, H.; Berdyugina, S. V.; Ilyin, I.; Strassmeier, K. G.; Weber, M.; Savanov, I.; Tuominen, I.

    2008-09-01

    Aims: In this paper we analyse photometric and spectroscopic observations of the young active dwarf V889 Her. We present new surface temperature maps, and compare them to earlier published Doppler maps, as well as to the results obtained from long-term photometry. Methods: The light curve inversions and surface temperature maps were obtained using the Occamian approach inversion technique. Results: The 12 years of photometric records on V889 Her suggest a possible photometric cycle of approximately 9 years. Variability on this time scale is detected in the maximum, minimum, and mean photometric magnitudes. The spots prefer to concentrate on two active longitudes that are approximately 180° apart. Furthermore, one flip-flop event, i.e., a sudden change of the dominant active longitude by 180°, is detected at the time of the global maximum activity. The wings of the Ca II 8662 Å indicate that the quiet photosphere of the V889 Her is similar to the one of the present Sun supporting earlier determined atmospheric parameters, while the chromosphere of V889 Her shows signs of much stronger activity. The temperature maps reveal that the polar regions are covered by spots, which are about 1500 K cooler than the quiet photosphere. The mean spot latitude varies slightly with time. It appears that the spot latitudes from our Doppler images and the spot migration rates revealed by photometry indicate a weaker differential rotation than reported earlier, but in the same (solar-like) direction. Based on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. Table [see full textsee full textsee full text] and Figs. [see full textsee full textsee full text]-[see full textsee full textsee full text] are only available in electronic form at http://www.aanda.org

  4. Nanoscale Roughness and Morphology Affect the IsoElectric Point of Titania Surfaces

    PubMed Central

    Borghi, Francesca; Vyas, Varun; Podestà, Alessandro; Milani, Paolo

    2013-01-01

    We report on the systematic investigation of the role of surface nanoscale roughness and morphology on the charging behaviour of nanostructured titania (TiO2) surfaces in aqueous solutions. IsoElectric Points (IEPs) of surfaces have been characterized by direct measurement of the electrostatic double layer interactions between titania surfaces and the micrometer-sized spherical silica probe of an atomic force microscope in NaCl aqueous electrolyte. The use of a colloidal probe provides well-defined interaction geometry and allows effectively probing the overall effect of nanoscale morphology. By using supersonic cluster beam deposition to fabricate nanostructured titania films, we achieved a quantitative control over the surface morphological parameters. We performed a systematical exploration of the electrical double layer properties in different interaction regimes characterized by different ratios of characteristic nanometric lengths of the system: the surface rms roughness Rq, the correlation length ξ and the Debye length λD. We observed a remarkable reduction by several pH units of IEP on rough nanostructured surfaces, with respect to flat crystalline rutile TiO2. In order to explain the observed behavior of IEP, we consider the roughness-induced self-overlap of the electrical double layers as a potential source of deviation from the trend expected for flat surfaces. PMID:23874708

  5. Factors affecting projected Arctic surface shortwave heating and albedo change in coupled climate models.

    PubMed

    Holland, Marika M; Landrum, Laura

    2015-07-13

    We use a large ensemble of simulations from the Community Earth System Model to quantify simulated changes in the twentieth and twenty-first century Arctic surface shortwave heating associated with changing incoming solar radiation and changing ice conditions. For increases in shortwave absorption associated with albedo reductions, the relative influence of changing sea ice surface properties and changing sea ice areal coverage is assessed. Changes in the surface sea ice properties are associated with an earlier melt season onset, a longer snow-free season and enhanced surface ponding. Because many of these changes occur during peak solar insolation, they have a considerable influence on Arctic surface shortwave heating that is comparable to the influence of ice area loss in the early twenty-first century. As ice area loss continues through the twenty-first century, it overwhelms the influence of changes in the sea ice surface state, and is responsible for a majority of the net shortwave increases by the mid-twenty-first century. A comparison with the Arctic surface albedo and shortwave heating in CMIP5 models indicates a large spread in projected twenty-first century change. This is in part related to different ice loss rates among the models and different representations of the late twentieth century ice albedo and associated sea ice surface state. PMID:26032318

  6. Charles Nordmann and Multicolour Stellar Photometry

    NASA Astrophysics Data System (ADS)

    Lequeux, James

    2010-11-01

    Charles Nordmann (1881-1940), an astronomer at the Paris Observatory, was the first to determine the effective temperature of stars with his photometre heterochrome, simultaneously and independently of Rosenberg, Wilsing and Scheiner in Germany. He is also the remote precursor of the multicolour photometry of Johnson and Morgan. In spite of the quality of his temperature determinations, which were as good or better than those made by spectrophotometry, he rapidly fell into oblivion because of some failures in his scientific work. We examine his activity in the international context of the time, and explain why he has been forgotten, to be rediscovered only recently.

  7. Photoelectric photometry of selected SAO stars. III

    NASA Technical Reports Server (NTRS)

    Scharlach, W. W. G.; Craine, E. R.

    1983-01-01

    Photometric observations of 131 SAO stars for use in calibrating data obtained from the Near Infrared Photographic Sky Survey (NIPSS) are reported. The serial numbers of the primary NIPSS program fields in which the photometry was done are shown along with the approximate position of each field and the number of stars observed in each field. The observations are listed, showing the SAO numbers of the program stars, their 1950 equatorial coordinates, the V magnitudes, and the (V-R) and (V-I) color indices. The mean errors in magnitudes and color indices obtained by averaging deviations from the mean for each star are on the order of 0.02 mag.

  8. Time Series Photometry of KZ Lacertae

    NASA Astrophysics Data System (ADS)

    Joner, Michael D.

    2016-01-01

    We present BVRI time series photometry of the high amplitude delta Scuti star KZ Lacertae secured using the 0.9-meter telescope located at the Brigham Young University West Mountain Observatory. In addition to the multicolor light curves that are presented, the V data from the last six years of observations are used to plot an O-C diagram in order to determine the ephemeris and evaluate evidence for period change. We wish to thank the Brigham Young University College of Physical and Mathematical Sciences as well as the Department of Physics and Astronomy for their continued support of the research activities at the West Mountain Observatory.

  9. Quick and Dirty WFPC2 Stellar Photometry

    NASA Technical Reports Server (NTRS)

    Mighell, Kenneth J.

    2001-01-01

    The latest release of the IRAF (Image Reduction and Analysis Facility) MXTOOLS package includes the new tasks QDWFPC2 (Quick and Dirty Wide Field and Planetary Camera, which does quick CCD (charge-coupled device) stellar photometry on two Hubble Space Telescope (HST) WFPC2 (Wide Field and Planetary Camera) observations: WFPC2COLOR, which converts HST WFPC2 instrumental magnitudes to standard colors using the Holtzman et al. color equations, and QDCMD (Quick and Dirty Color Magnitude Diagram), which reads the output of WFPC2COLOR and displays a color-magnitude diagram on a user-chosen graphics device.

  10. New BVR Photometry of BL Camelopardalis

    NASA Astrophysics Data System (ADS)

    Joner, Michael D.

    2015-01-01

    New BVR photometry of the SX Phe star BL Camelopardalis has been secured with the 0.9 m reflector at the BYU West Mountain Observatory. The new data have been used to determine times of maximum light, standardize light curves in each of the three filters, and examine the frequencies that are currently detectable in the light curves from a single location.We acknowledge the Brigham Young University College of Physical and Mathematical Sciences as well as the Department of Physics and Astronomy for continued support of this and other research efforts currently being done at the West Mountain Observatory.

  11. Near Infrared Photometry of Nova Del 2013

    NASA Astrophysics Data System (ADS)

    Cass, C. A.; Carlon, L. R.; Corgan, T. D.; Dykhoff, A. D.; Gehrz, D. R.; Shenoy, P. D.

    2013-08-01

    Subjects: Infra-Red, Nova We report RIJHKLM photometry of Nova Del 2013 taken on August 28.13 UT using an As:Si bolometer mounted on the 0.76-m infrared telescope of the University of Minnesota's O'Brien Observatory (Marine on St. Croix, Minnesota, USA). Vega (alpha Lyrae) was used as the standard star. On this date we find: R = 5.6 +/- 0.1, I = 5.2 +/- 0.1, J = 4.5 +/- 0.1, H = 4.7 +/- 0.1, K = 4.7 +/- 0.1, L = 3.3 +/- 0.2, M = +1.8 +/- 0.3.

  12. Photometry and polarimetry of V 1057 Cygni.

    NASA Technical Reports Server (NTRS)

    Rieke, G.; Lee, T.; Coyne, G.

    1972-01-01

    Evaluation of extensive photometric and polarimetric data over a six-month interval for V 1057 Cyg. The polarization appears to be constant and of interstellar origin; the photometry, which extends nearly six octaves from the ultraviolet to 22 microns in the infrared, indicates that the total observed luminosity is decreasing - having now declined about 10% from its earlier level. A model characterized by two circumstellar shells which absorb and reradiate short-wavelength stellar flux from an underlying A1-type star provides the best fit to the observational data. The present variability, however, cannot be due to circumstellar activity, but appears to originate in the star itself.

  13. Factors affecting the spontaneous motion of condensate drops on superhydrophobic copper surfaces.

    PubMed

    Feng, Jie; Qin, Zhaoqian; Yao, Shuhuai

    2012-04-10

    The coalescence-induced condensate drop motion on some superhydrophobic surfaces (SHSs) has attracted increasing attention because of its potential applications in sustained dropwise condensation, water collection, anti-icing, and anticorrosion. However, an investigation of the mechanism of such self-propelled motion including the factors for designing such SHSs is still limited. In this article, we fabricated a series of superhydrophobic copper surfaces with nanoribbon structures using wet chemical oxidation followed by fluorization treatment. We then systematically studied the influence of surface roughness and the chemical properties of as-prepared surfaces on the spontaneous motion of condensate drops. We quantified the "frequency" of the condensate drop motion based on microscopic sequential images and showed that the trend of this frequency varied with the nanoribbon structure and extent of fluorination. More obvious spontaneous condensate drop motion was observed on surfaces with a higher extent of fluorization and nanostructures possessing sufficiently narrow spacing and higher perpendicularity. We attribute this enhanced drop mobility to the stable Cassie state of condensate drops in the dynamic dropwise condensation process that is determined by the nanoscale morphology and local surface energy. PMID:22424422

  14. Changes in droplet surface tension affect the observed hygroscopicity of photochemically aged biomass burning aerosol.

    PubMed

    Giordano, Michael R; Short, Daniel Z; Hosseini, Seyedehsan; Lichtenberg, William; Asa-Awuku, Akua A

    2013-10-01

    This study examines the hygroscopic and surface tension properties as a function of photochemical aging of the aerosol emissions from biomass burning. Experiments were conducted in a chamber setting at the UC-Riverside Center for Environmental Research and Technology (CE-CERT) Atmospheric Processes Lab using two biomass fuel sources, manzanita and chamise. Cloud condensation nuclei (CCN) measurements and off-line filter sample analysis were conducted. The water-soluble organic carbon content and surface tension of the extracted filter samples were measured. Surface tension information was then examined with Köhler theory analysis to calculate the hygroscopicity parameter, κ. Laboratory measurement of biomass burning smoke from two chaparral fuels is shown to depress the surface tension of water by 30% or more at organic matter concentrations relevant at droplet activation. Accounting for surface tension depression can lower the calculated κ by a factor of 2. This work provides evidence for surface tension depression in an important aerosol system and may provide closure for differing sub- and supersaturated κ measurements. PMID:23957441

  15. Colloidal mobilization of arsenic from mining-affected soils by surface runoff.

    PubMed

    Gomez-Gonzalez, Miguel Angel; Voegelin, Andreas; Garcia-Guinea, Javier; Bolea, Eduardo; Laborda, Francisco; Garrido, Fernando

    2016-02-01

    Scorodite-rich wastes left as a legacy of mining and smelting operations pose a threat to environmental health. Colloids formed by the weathering of processing wastes may control the release of arsenic (As) into surface waters. At a former mine site in Madrid (Spain), we investigated the mobilization of colloidal As by surface runoff from weathered processing wastes and from sediments in the bed of a draining creek and a downstream sedimentation-pond. Colloids mobilized by surface runoff during simulated rain events were characterized for their composition, structure and mode of As uptake using asymmetric flow field-flow fractionation coupled to inductively plasma mass spectrometry (AF4-ICP-MS) and X-ray absorption spectroscopy (XAS) at the As and Fe K-edges. Colloidal scorodite mobilized in surface runoff from the waste pile is acting as a mobile As carrier. In surface runoff from the river bed and the sedimentation pond, ferrihydrite was identified as the dominant As-bearing colloidal phase. The results from this study suggest that mobilization of As-bearing colloids by surface runoff may play an important role in the dispersion of As from metallurgical wastes deposited above ground and needs to be considered in risk assessment. PMID:26454721

  16. Abiotic Factors Affecting the Persistence of Avian Influenza Virus in Surface Waters of Waterfowl Habitats

    PubMed Central

    Dalton, Melinda S.; Cressler, Alan M.; Berghaus, Roy D.; Stallknecht, David E.

    2014-01-01

    Avian influenza (AI) virus can remain infectious in water for months, and virus-contaminated surface water is considered to be a source of infection within wild waterfowl populations. Previous work has characterized the effects of pH, salinity, and temperature on viral persistence in water, but most of that work was done with modified distilled water. The objective of this study was to identify the abiotic factors that influence the duration of AI virus persistence in natural surface water. Surface water samples were collected from 38 waterfowl habitats distributed across the United States. Samples were submitted to the U.S. Geological Survey National Water Quality Laboratory for chemical analysis and the University of Georgia for viral reduction time analysis. Samples were filtered with 0.22-μm filters, and the durations of persistence of three wild-bird-derived influenza A viruses within each water sample at 10, 17, and 28°C were determined. The effects of the surface water physicochemical factors on the duration of AI viral persistence in laboratory experiments were evaluated by multivariable linear regression with robust standard errors. The duration of AI virus persistence was determined to be longest in filtered surface water with a low temperature (<17°C), a neutral-to-basic pH (7.0 to 8.5), low salinity (<0.5 ppt), and a low ammonia concentration (<0.5 mg/liter). Our results also highlighted potential strain-related variation in the stability of AI virus in surface water. These results bring us closer to being able to predict the duration of AI virus persistence in surface water of waterfowl habitats. PMID:24584247

  17. Learning beyond the Surface: Engaging the Cognitive, Affective and Spiritual Dimensions within the Curriculum

    ERIC Educational Resources Information Center

    Buchanan, Michael T.; Hyde, Brendan

    2008-01-01

    In Australia the separation of mind, body and spirit by secular society has had a significant influence on educational trends. An outcomes-based approach to education, with an emphasis on cognitive learning, has meant that the affective and spiritual dimensions of students' lives have often been understated. Classroom programs in religious

  18. Learning beyond the Surface: Engaging the Cognitive, Affective and Spiritual Dimensions within the Curriculum

    ERIC Educational Resources Information Center

    Buchanan, Michael T.; Hyde, Brendan

    2008-01-01

    In Australia the separation of mind, body and spirit by secular society has had a significant influence on educational trends. An outcomes-based approach to education, with an emphasis on cognitive learning, has meant that the affective and spiritual dimensions of students' lives have often been understated. Classroom programs in religious…

  19. Surface and subsurface geologic risk factors to ground water affecting brownfield redevelopment potential.

    PubMed

    Kaufman, Martin M; Murray, Kent S; Rogers, Daniel T

    2003-01-01

    A model is created for assessing the redevelopment potential of brownfields. The model is derived from a space and time conceptual framework that identifies and measures the surface and subsurface risk factors present at brownfield sites. The model then combines these factors with a contamination extent multiplier at each site to create an index of redevelopment potential. Results from the application of the model within an urbanized watershed demonstrate clear differences between the redevelopment potential present within five different near-surface geologic units, with those units containing clay being less vulnerable to subsurface contamination. With and without the extent multiplier, the total risk present at the brownfield sites within all the geologic units is also strongly correlated to the actual costs of remediation. Thus, computing the total surface and subsurface risk within a watershed can help guide the remediation efforts at broad geographic scales, and prioritize the locations for redevelopment. PMID:12708672

  20. How linear surface waves are affected by a current with constant vorticity

    NASA Astrophysics Data System (ADS)

    Ellingsen, Simen .; Brevik, Iver

    2014-03-01

    The interaction of surface waves with Couette-type current with uniform vorticity is a well suited problem for students approaching the theory of surface waves. The problem, although mathematically simple, contains rich physics, and is moreover important in several situations from oceanography and marine technology to microfluidics. We here lay out a simple two-dimensional theory of waves propagating upon a basic flow of uniform vorticity of constant depth. The dispersion relation is found, showing how the shearing current introduces different phase velocities for upstream and downstream propagating waves. The role of the surface tension is discussed and applied to the case of a wave pattern created by a moving source, stationary as seen by the source. We conclude by discussing how the average potential and kinetic energies are no longer equal in the presence of shear.

  1. Surface Chemical Gradient Affects the Differentiation of Human Adipose-Derived Stem Cells via ERK1/2 Signaling Pathway.

    PubMed

    Liu, Xujie; Shi, Shengjun; Feng, Qingling; Bachhuka, Akash; He, Wei; Huang, Qianli; Zhang, Ranran; Yang, Xing; Vasilev, Krasimir

    2015-08-26

    To understand the role of surface chemistry on cell behavior and the associated molecular mechanisms, we developed and utilized a surface chemical gradient of amine functional groups by carefully adjusting the gas composition of 1,7-octadiene (OD) and allylamine (AA) of the plasma phase above a moving substrate. The chemical gradient surface used in the present work shows an increasing N/C ratio and wettability from the OD side toward the AA side with no change in surface topography. Under standard culture conditions (with serum), human adipose-derived stem cells (hASCs) adhesion and spreading area increased toward the AA side of the gradient. However, there were no differences in cell behavior in the absence of serum. These results, supported by the trends in proteins adsorption on the gradient surface, demonstrated that surface chemistry affects the response of hASCs through cell-adhesive serum proteins, rather than interacting directly with the cells. The expression of p-ERK and the osteogenic differentiation increased toward the AA side of the gradient, while adipogenic differentiation decreased in the same direction; however, when the activation of ERK1/2 was blocked by PD98059, the levels of osteogenic or adipogenic differentiation on different regions of the chemical gradient were the same. This indicates that ERK1/2 may be an important downstream signaling pathway of surface chemistry directed stem cell fate. PMID:26237746

  2. How subsurface patterns affect surface energy budget patterns: a sudanian case study

    NASA Astrophysics Data System (ADS)

    Robert, D.; Cohard, J.; Descloitres, M.; Vandervaere, J.; Braud, I.; Vauclin, M.

    2011-12-01

    Fractured bedrock areas are still challenging for hydrological modeling because of their complex underground property distributions. The heterogeneity in soil hydraulic properties, for example, can control the subsurface water fluxes and create surface soil moisture pattern which becomes preferential areas for runoff production or evapotranspiration. This study aimed to evaluate the impact of a bedrock topography, including outcropping, on subsurface water fluxes and the induced energy budget patterns at the surface. To deal with these ground water/surface water interactions, we run the Parflow-CLM distributed coupled land surface and groundwater model over the 12km2 Ara watershed (Northern Benin) for different bedrock configurations. The Ara catchment is submitted to a sudanian climate with 1200mm total rainfall per year. It is part of the AMMA-Catch project in which 3 meso sites have been documented along a south to north transect in West Africa. The geology of the Ara catchment is composed of metamorphic rocks. The main orientation of the geological structures (and of the gneiss foliation) is roughly north-south and the dip angle is 20° east. These structure create patterns in effective porosity distribution which is supposed to induce subsurface flow perpendicular to surface slope direction. Controlled Parflow-CLM simulation results are compared with energy budget data, including 3 net radiation measurements, eddy covariance station, scintillometric measurements to estimate evapotranspiration at different scales. The experimental device also include ground measurements like distributed surface soil moisture profile and piezometers. Parflow-CLM simulations are in good agreement with energy budget observations if observed Leaf Area Index time series are take into account. Then different hydraulic property distributions (effective porosity, hydraulic transmissivity, water retention curves) are evaluated through watershed dynamic differences.

  3. Cobalt and chromium exposure affects osteoblast function and impairs the mineralization of prosthesis surfaces in vitro.

    PubMed

    Shah, Karan M; Wilkinson, Jeremy Mark; Gartland, Alison

    2015-11-01

    Cobalt (Co) and chromium (Cr) ions and nanoparticles equivalent to those released through tribo-corrosion of prosthetic metal-on-metal (MOM) bearings and taper junctions are detrimental to osteoblast activity and function in vitro when examined as individual species. Here we examined the effects of Co(2+):Cr(3+) and Co(2+):Cr(6+) combinations on osteoblast-like SaOS-2 cellular activity, alkaline phosphatase (ALP) activity and mineralization to better reflect clinical exposure conditions in vivo. We also assessed the effect of Co(2+):Cr(3+) combinations and Co:Cr nanoparticles on SaOS-2 cell osteogenic responses on grit-blasted, plasma-sprayed titanium-coated, and hydroxyapatite-coated prosthesis surfaces. Cellular activity and ALP activity were reduced to a greater extent with combination treatments compared to individual ions. Co(2+) and Cr(3+) interacted additively and synergistically to reduce cellular activity and ALP activity, respectively, while the Co(2+) with Cr(6+) combination was dominated by the effect of Cr(6+) alone. Mineralization by osteoblasts was greater on hydroxyapatite-coated surfaces compared to grit-blasted and plasma-sprayed titanium-coated surfaces. Treatments with Co(2+):Cr(3+) ions and Co:Cr nanoparticles reduced the percentage mineralization on all surfaces, with hydroxyapatite-coated surfaces having the least reduction. In conclusion, our data suggests that previous studies investigating individual metal ions underestimate their potential clinical effects on osteoblast activity. Furthermore, the data suggests that hydroxyapatite-coated surfaces may modulate osteoblast responses to metal debris. PMID:25929464

  4. How do slope and surface roughness affect plot-scale overland flow connectivity?

    NASA Astrophysics Data System (ADS)

    Peñuela, Andrés; Javaux, Mathieu; Bielders, Charles L.

    2015-09-01

    Surface micro-topography and slope drive the hydrological response of plots through the gradual filling of depressions as well as the establishment of hydraulic connections between overflowing depressions. Therefore, quantifying and understanding the effects of surface roughness and slope on plot-scale overland flow connectivity is crucial to improve current hydrological modeling and runoff prediction. This study aimed at establishing predictive equations relating structural and functional connectivity indicators in function of slope and roughness. The Relative Surface Connection function (RSCf) was used as a functional connectivity indicator was applied. Three characteristic parameters were defined to characterize the RSCf: the surface initially connected to the outlet, the connectivity threshold and the maximum depression storage (DSmax). Gaussian surface elevation fields (6 m × 6 m) were generated for a range of slopes and roughnesses (sill σ and range R of the variogram). A full factorial of 6 slopes (0-15%), 6 values of R (50-400 mm) and 6 values of σ (2-40 mm) was considered, and the RSCf calculated for 10 realizations of each combination. Results showed that the characteristic parameters of the RSCf are greatly influenced by R, σ and slope. At low slopes and high ratios of σ/2R, the characteristic parameters of the RSCf appear linked to a single component of the surface roughness (R or σ). On the contrary, both R and σ are needed to predict the RSCf at high slopes and low ratios of σ/2R. A simple conceptualization of surface depressions as rectangles, whose shape was determined by R and σ, allowed deriving simple mathematical expressions to estimate the characteristic parameters of the RSCf in function of R, σ and slope. In the case of DSmax, the proposed equation performed better than previous empirical expressions found in the literature which do not account for the horizontal component of the surface roughness. The proposed expressions allow estimating the characteristic points of the RSCf with reasonable accuracy and could therefore prove useful for integrating plot-scale overland flow connectivity into hydrological models whenever the RSCf presents a well-defined connectivity threshold.

  5. JHK photometry of selected Trojan and Hilda asteroids

    NASA Technical Reports Server (NTRS)

    Smith, Dale W.; Johnson, Paul E.; Buckingham, William L.; Shorthill, Richard W.

    1992-01-01

    No entirely satisfactory match has been established between the present JHK photometry of selected Hilda and Trojan asteroids and photometry for both main belt asteroids and laboratory samples. It is noted that while the leading Trojans and Hildas exhibit similar and homogeneous JHK colors, the trailing Trojans appear to be more heterogeneous. Charcoal and magnetite provide the best match in terms of JHK colors.

  6. Sub-surface soil carbon changes affects biofuel greenhouse gas emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Changes in direct soil organic carbon (SOC) can have a major impact on overall greenhouse gas (GHG) emissions from biofuels when using life-cycle assessment (LCA). Estimated changes in SOC, when accounted for in an LCA, are typically derived from near-surface soil depths (<30 cm). Changes in subsurf...

  7. Surface and ground water quality in a restored urban stream affected by road salts

    EPA Science Inventory

    In 2001 research began in Minebank Run, MD to examine the impact of restoration on water quality. Our research area was to determine if road salts in the surface and ground waters are detrimental to the stream channel restoration. The upstream reach (UP), above the Baltimore I-...

  8. EFFECTS OF GRAZING MANAGEMENT ON PASTURE CHARACTERISTICS AFFECTING SEDIMENT AND NUTRIENT LOADS IN SURFACE WATERS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To evaluate cattle grazing effects on the potential for sediment and nutrient loading of surface waters, forage cover, sward height, and mass and manure cover were measured in pastures with different grazing management systems. Six 12.1-ha cool-season grass pastures were assigned one of three treat...

  9. Detoxification of Implant Surfaces Affected by Peri-Implant Disease: An Overview of Surgical Methods

    PubMed Central

    Wilson Jr, Thomas G.

    2013-01-01

    Purpose. Peri-implantitis is one of the major causes of implant failure. The detoxification of the implant surface is necessary to obtain reosseointegration. The aim of this review was to summarize in vitro and in vivo studies as well as clinical trials that have evaluated surgical approaches for detoxification of the implant body surfaces. Materials and Methods. A literature search was conducted using MEDLINE (PubMed) from 1966 to 2013. The outcome variables were the ability of the therapeutic method to eliminate the biofilm and endotoxins from the implant surface, the changes in clinical parameters, radiographic bone fill, and histological reosseointegration. Results. From 574 articles found, 76 were analyzed. The findings, advantages, and disadvantages of using mechanical, chemical methods and lasers are discussed. Conclusions. Complete elimination of the biofilms is difficult to achieve. All therapies induce changes of the chemical and physical properties of the implant surface. Partial reosseointegration after detoxification has been reported in animals. Combination protocols for surgical treatment of peri-implantitis in humans have shown some positive clinical and radiographic results, but long-term evaluation to evaluate the validity and reliability of the techniques is needed. PMID:23983691

  10. Physiological variables affecting surface film formation by native lamellar body-like pulmonary surfactant particles.

    PubMed

    Hobi, Nina; Siber, Gerlinde; Bouzas, Virginia; Ravasio, Andrea; Prez-Gil, Jesus; Haller, Thomas

    2014-07-01

    Pulmonary surfactant (PS) is a surface active complex of lipids and proteins that prevents the alveolar structures from collapsing and reduces the work of breathing by lowering the surface tension at the alveolar air-liquid interface (ALI). Surfactant is synthesized by the alveolar type II (AT II) cells, and it is stored in specialized organelles, the lamellar bodies (LBs), as tightly packed lipid bilayers. Upon secretion into the alveolar lining fluid, a large fraction of these particles retain most of their packed lamellar structure, giving rise to the term lamellar body like-particles (LBPs). Due to their stability in aqueous media, freshly secreted LBPs can be harvested from AT II cell preparations. However, when LBPs get in contact with an ALI, they quickly and spontaneously adsorb into a highly organized surface film. In the present study we investigated the adsorptive capacity of LBPs at an ALI under relevant physiological parameters that characterize the alveolar environment in homeostatic or in pathological conditions. Adsorption of LBPs at an ALI is highly sensitive to pH, temperature and albumin concentration and to a relatively lesser extent to changes in osmolarity or Ca(2+) concentrations in the physiological range. Furthermore, proteolysis of LBPs significantly decreases their adsorptive capacity confirming the important role of surfactant proteins in the formation of surface active films. PMID:24582711

  11. Investigations on temperature distribution of satellite surfaces affected by solar absorptivity

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Pan, X. X.; Li, G. H.; Liu, X.; Jiang, L. X.

    2010-09-01

    Based on the Monte Carlo ray-tracing method, the network coefficients of thermal network model describing the radiation heat transfer among satellite surfaces is solved by considering the surface material optical characters. It is superiority to the conventional Gebhart's method in view of the grey body and the diffuse reflection assumptions. The zone leveling method is used to discrete the governing equations and the solar absorpivity is separated and considered to be an important correction parameter. Effects of the solar incidence round angle, the zenith angle and the ratio of absorpivity to emissivity (RAE) on temperature distribution are numerically simulated and discussed in detail. The higher or the lower the RAE may be lead to the alternative heating and cooling tend with a larger heating or cooling velocity of main body surfaces than the solar array surfaces. Furthermore, maximum temperature of main body is almost larger than solar arrays. Under the same RAE, solar incidence angle make a great effect on the uniform character of temperature distribution.

  12. Photometry of dark atmosphereless planetary bodies: an efficient numerical model

    NASA Astrophysics Data System (ADS)

    Wilkman, Olli; Muinonen, Karri; Peltoniemi, Jouni

    2015-12-01

    We present a scattering model for regolith-covered Solar System bodies. It can be used to compute the intensity of light scattered by a surface consisting of packed, mutually shadowing particles. Our intention is to provide a model in which other researchers can apply in studies of Solar System photometry. Our model is a Lommel-Seeliger type model, representing a medium composed of individual scatterers with small single-scattering albedo. This means that it is suitable for dark regolith surfaces such as the Moon and many classes of asteroids. Our model adds an additional term which takes into account the mutual shadowing between the scatterers. The scatterers can have an arbitrary phase function. We use a numerical ray-tracing simulation to compute the shadowing contribution. We present the model in a form which makes implementing it in existing software straightforward and fast. The model in practice is implemented as files containing pre-computed values of the surface reflection coefficient, which can be loaded into a user's program and used to compute the scattering in the desired viewing geometries. As the usage requires only a little simple arithmetic and a table look-up, it is as fast to use as common analytical models.

  13. Ten Recent Enhancements To Aperture Photometry Tool

    NASA Astrophysics Data System (ADS)

    Laher, Russ; Rebull, L. M.; Gorjian, V.

    2013-01-01

    Aperture Photometry Tool is free, multi-platform, easy-to-install software for astronomical research, as well as for learning, visualizing, and refining aperture-photometry analyses. This mature software has been under development for five years, and is a silent workhorse of the NASA/IPAC Teacher Archive Research Program. Software version 2.1.5 is described by Laher et al., Publications of the Astronomical Society of the Pacific, Vol. 124, No. 917, pp. 737-763, (July 2012). Four software upgrades have been released since the publication, which include new capabilities, increased speed, more user-friendliness, and some minor bug fixes. Visit www.aperturephotometry.org to download the latest version. The enhancements are as follows: 1) Added new Tools menu option to write selected primary-image data to a comma-separated-value file (for importing into Excel); 2) Added a new display of the color-table levels on a separate panel; 3) Added a new tool to measure the angular separation between positions on the thumbnail image, via mouse-cursor drag and release; 4) Added a new tool to overlay an aperture at user-specified coordinates (in addition to aperture overlay via mouse click); 5) Speeded up the source-list tool with optional multithreading in its automatic mode (allowed thread number is user-specifiable); 6) Added a new “Number” column to the output aperture-photometry-table file in order to track the input source order (multithreading reorders the output); 7) Upgraded the source-list tool to accept input source lists containing positions in sexagesimal equatorial coordinates (in addition to decimal degrees, or, alternatively, pixel coordinates); 8) Added a new decimal/sexagesimal converter; 9) Upgraded the source-list creation tool to compute the detection threshold using robust estimates of the local background and local data dispersion, where the user can select the grid and window sizes for these local calculations; and 10) Modified the batch mode to optionally generate a source list. These upgrades increase the software's utility, and more improvements are planned for future releases.

  14. Retention of potentially mobile radiocesium in forest surface soils affected by the Fukushima nuclear accident

    PubMed Central

    Koarashi, Jun; Moriya, Koichi; Atarashi-Andoh, Mariko; Matsunaga, Takeshi; Fujita, Hiroki; Nagaoka, Mika

    2012-01-01

    The fate of 137Cs derived from the Fukushima nuclear accident fallout and associated radiological hazards are largely dependent on its mobility in the surface soils of forest ecosystems. Thus, we quantified microbial and adsorptive retentions of 137Cs in forest surface (0–3 cm) soils. The K2SO4 extraction process liberated 2.1%–12.8% of the total 137Cs from the soils. Two soils with a higher content of clay- and silt-sized particles, organic carbon content, and cation exchange capacity showed higher 137Cs extractability. Microbial biomass was observed in all of the soils. However, the 137Cs extractability did not increase after destruction of the microbial biomass by chloroform fumigation, providing no evidence for microbial retention of the Fukushima-fallout 137Cs. The results indicate that uptake of 137Cs by soil microorganisms is less important for retention of potentially mobile 137Cs in the forest surface soils compared to ion-exchange adsorption on non-specific sites provided by abiotic components. PMID:23256039

  15. Different Culture Media Affect Proliferation, Surface Epitope Expression, and Differentiation of Ovine MSC

    PubMed Central

    Tolba, René; Jahnen-Dechent, Wilhelm; Lethaus, Bernd; Neuss, Sabine

    2013-01-01

    Orthopedic implants including engineered bone tissue are commonly tested in sheep. To avoid rejection of heterologous or xenogeneic cells, autologous cells are preferably used, that is, ovine mesenchymal stem cells (oMSC). Unlike human MSC, ovine MSC are not well studied regarding isolation, expansion, and characterization. Here we investigated the impact of culture media composition on growth characteristics, differentiation, and surface antigen expression of oMSC. The culture media varied in fetal calf serum (FCS) content and in the addition of supplements and/or additional epidermal growth factor (EGF). We found that FCS strongly influenced oMSC proliferation and that specific combinations of supplemental factors (MCDB-201, ITS-plus, dexamethasone, and L-ascorbic acid) determined the expression of surface epitopes. We compared two published protocols for oMSC differentiation towards the osteogenic, adipogenic, and chondrogenic fate and found (i) considerable donor to donor variations, (ii) protocol-dependent variations, and (iii) variations resulting from the preculture medium composition. Our results indicate that the isolation and culture of oMSC in different growth media are highly variable regarding oMSC phenotype and behaviour. Furthermore, variations from donor to donor critically influence growth rate, surface marker expression, and differentiation. PMID:24228035

  16. Factors affecting sorption of nitro explosives to biochar: pyrolysis temperature, surface treatment, competition, and dissolved metals.

    PubMed

    Oh, Seok-Young; Seo, Yong-Deuk

    2015-05-01

    The application of rice straw-derived biochar for removing nitro explosives, including 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), from contaminated water was investigated through batch experiments. An increase in the pyrolysis temperature from 250 to 900°C in general led to higher pH, surface area, cation exchange capacity (CEC), point of zero charge, and C:O ratio of biochar. The maximum sorption capacity estimated by a mixed sorption-partition model increased when pyrolysis temperatures were elevated from 250 to 900°C, indicating that C content and aromaticity of biochar were strongly related to the sorption of nitro explosives to biochar. Surface treatment with acid or oxidant increased the sorption capacity of biochar for the two strong π-acceptor compounds (DNT and TNT) but not for RDX. However, the enhancement of sorption capacity was not directly related to increased surface area and CEC. Compared with single-sorption systems, coexistence of explosives or cationic metals resulted in decreased sorption of each explosive to biochar, suggesting that sorption of nitro explosives and cationic metals to electron-rich portions in biochar was competitive. Our results suggest that π-π electron donor acceptor interactions are main sorption mechanisms and that changing various conditions can enhance or reduce the sorption of nitro explosives to biochar. PMID:26024263

  17. Polarimetric Retrievals of Surface and Cirrus Clouds Properties in the Region Affected by the Deepwater Horizon Oil Spill

    NASA Technical Reports Server (NTRS)

    Ottaviani, Matteo; Cairns, Brian; Chowdhary, Jacek; Van Diedenhoven, Bastiaan; Knobelspiesse, Kirk; Hostetler, Chris; Ferrare, Rich; Burton, Sharon; Hair, John; Obland, Michael D.; Rogers, Raymond

    2012-01-01

    In 2010, the Goddard Institute for Space Studies (GISS) Research Scanning Polarimeter (RSP) performed several aerial surveys over the region affected by the oil spill caused by the explosion of the Deepwater Horizon offshore platform. The instrument was deployed on the NASA Langley B200 aircraft together with the High Spectral Resolution Lidar (HSRL), which provides information on the distribution of the aerosol layers beneath the aircraft, including an accurate estimate of aerosol optical depth. This work illustrates the merits of polarization measurements in detecting variations of ocean surface properties linked to the presence of an oil slick. In particular, we make use of the degree of linear polarization in the glint region, which is severely affected by variations in the refractive index but insensitive to the waviness of the water surface. Alterations in the surface optical properties are therefore expected to directly affect the polarization response of the RSP channel at 2264 nm, where both molecular and aerosol scattering are negligible and virtually all of the observed signal is generated via Fresnel reflection at the surface. The glint profile at this wavelength is fitted with a model which can optimally estimate refractive index, wind speed and direction, together with aircraft attitude variations affecting the viewing geometry. The retrieved refractive index markedly increases over oil-contaminated waters, while the apparent wind speed is significantly lower than in adjacent uncontaminated areas, suggesting that the slick dampens high-frequency components of the ocean wave spectrum. The constraint on surface reflectance provided by the short-wave infrared channels is a cornerstone of established procedures to retrieve atmospheric aerosol microphysical parameters based on the inversion of the RSP multispectral measurements. This retrieval, which benefits from the ancillary information provided by the HSRL, was in this specific case hampered by prohibitive variability in atmospheric conditions (very inhomogeneous aerosol distribution and cloud cover). Although the results presented for the surface are essentially unaffected, we discuss the results obtained by typing algorithms in sorting the complex mix of aerosol types, and show evidence of oriented ice in cirrus clouds present in the area. In this context, polarization measurements at 1880 nm were used to infer ice habit and cirrus optical depth, which was found in the subvisual/threshold-visible regime, confirming the utility of the aforementioned RSP channel for the remote sensing of even thin cold clouds.

  18. Surface variations affecting human dental enamel studied using nanomechanical and chemical analysis

    NASA Astrophysics Data System (ADS)

    Dickinson, Michelle Emma

    The enamel surface is the interface between the tooth and its ever changing oral environment. Cavity (caries) formation and extrinsic tooth staining are due, respectively, to degradation of the enamel structure under low pH conditions and interactions between salivary pellicle and dietary elements. Both of these occur at the enamel surface and are caused by the local environment changing the chemistry of the surface. The results can be detrimental to the enamel's mechanical integrity and aesthetics. Incipient carious lesions are the precursor to caries and form due to demineralisation of enamel. These carious lesions are a reversible structure where ions (e.g. Ca2+, F -) can diffuse in (remineralisation) to preserve the tooth's structural integrity. This investigation used controlled in vitro demineralisation and remineralisation to study artificial carious lesion formation and repair. The carious lesions were cross-sectioned and characterised using nanoindentation, electron probe micro-analysis and time of flight secondary ion mass spectrometry. Mechanical and chemical maps showed the carious lesion had a significantly reduced hardness and elastic modulus, and the calcium and phosphate content was lower than in sound enamel. Fluoride based remineralisation treatments gave a new phase (possibly fluorohydroxyapatite) within the lesion with mechanical properties higher than sound enamel. The acquired salivary pellicle is a protein-rich film formed by the physisorption of organic molecules in saliva onto the enamel surface. Its functions include lubrication during mastication and chemical protection. However, pellicle proteins react with dietary elements such as polyphenols (tannins in tea) causing a brown stain. This study has used in vitro dynamic nanoindentation and atomic force microscopy to examine normal and stained pellicles formed in vivo. The effects of polyphenols on the pellicle's mechanical properties and morphology have been studied. It was found that the initial adsorption of proteins occurred within 30 seconds of exposure to the oral cavity; fully mature pellicles develop in 2 hours. Polyphenol staining resulted in substantial changes in the morphology and mechanical properties of the pellicle. Specifically, staining gives pellicles consisting of large globules with high surface adhesion and a high loss tangent. These changes help explain why extrinsic stains are difficult to remove abrasively.

  19. TERMS PHOTOMETRY OF KNOWN TRANSITING EXOPLANETS

    SciTech Connect

    Dragomir, Diana; Kane, Stephen R.; Ciardi, David R.; Gelino, Dawn M.; Payne, Alan; Ramirez, Solange V.; Von Braun, Kaspar; Wyatt, Pamela; Pilyavsky, Genady; Mahadevan, Suvrath; Wright, Jason T.; Zachary Gazak, J.; Rabus, Markus

    2011-10-15

    The Transit Ephemeris Refinement and Monitoring Survey conducts radial velocity and photometric monitoring of known exoplanets in order to refine planetary orbits and predictions of possible transit times. This effort is primarily directed toward planets not known to transit, but a small sample of our targets consists of known transiting systems. Here we present precision photometry for six WASP (Wide Angle Search for Planets) planets acquired during their transit windows. We perform a Markov Chain Monte Carlo analysis for each planet and combine these data with previous measurements to redetermine the period and ephemerides for these planets. These observations provide recent mid-transit times which are useful for scheduling future observations. Our results improve the ephemerides of WASP-4b, WASP-5b, and WASP-6b and reduce the uncertainties on the mid-transit time for WASP-29b. We also confirm the orbital, stellar, and planetary parameters of all six systems.

  20. Techniques for Automated Single-Star Photometry

    NASA Astrophysics Data System (ADS)

    Henry, Gregory W.

    2001-02-01

    Tennessee State University operates several automatic photoelectric telescopes (APTs) located at Fairborn Observatory in the Patagonia Mountains of southern Arizona. The APTs are dedicated to photometric monitoring programs that would be expensive and difficult to accomplish without the advantages of automation. I review the operation of two of the telescopes (a 0.75- and 0.80-meter (m) APT) and the quality-control techniques that result in the routine acquisition of single-star differential photometry with a precision of 0.001 mag for single observations and 0.0001 - 0.0002 mag for seasonal means. I also illustrate the capabilities of the APTS with sample results from a program to measure luminosity cycles in sun-like stars and a related program to search for the signatures of extrasolar planets around these stars.

  1. Techniques for Automated Single-Star Photometry

    NASA Technical Reports Server (NTRS)

    Henry, Gregory W.

    2001-01-01

    Tennessee State University operates several automatic photoelectric telescopes (APTs) located at Fairborn Observatory in the Patagonia Mountains of southern Arizona. The APTs are dedicated to photometric monitoring programs that would be expensive and difficult to accomplish without the advantages of automation. I review the operation of two of the telescopes (a 0.75- and 0.80-meter (m) APT) and the quality-control techniques that result in the routine acquisition of single-star differential photometry with a precision of 0.001 mag for single observations and 0.0001 - 0.0002 mag for seasonal means. I also illustrate the capabilities of the APTS with sample results from a program to measure luminosity cycles in sun-like stars and a related program to search for the signatures of extrasolar planets around these stars.

  2. Photometry and Spectroscopy of 47 Cassiopeiae

    NASA Astrophysics Data System (ADS)

    Garner, H. L.; Etzel, P. B.

    1998-05-01

    The HIPPARCOS catalog lists the young rapidly rotating F0 V star 47 Cassiopeiae as a close visual binary. The orbit of the photocenter yields a semi-major axis of 39.3 mas and a period of 1616 days. Gudel et al. (1998, Tenth Cambridge Conference on Cool Stars and the Sun) discuss the puzzle of this system as evidenced by its high X-Ray flux (ROSAT All-Sky Survey), its strong radio flux (6 cm), and indications of rotational modulation in these bands with a period of about one day. Such signatures of coronal activity are not normally associated with early F-type main-sequence stars. Photometry (1996-1997) and spectroscopy (1994-1997) from SDSU's Mount Laguna Observatory will be presented and discussed in connection with the anomalous behavior of the system. Our photometry shows no evidence of rotational modulation, which might be consistent with large star-spot groups, nor any evidence of flaring events. Our spectroscopy does not show any evidence of emission or other forms of line variability at H-alpha that are normally associated with chromospheric activity. However, we do find evidence of radial velocity variations that are consistent with those expected from the HIPPARCOS orbit. Our preliminary orbit is consistent with the interpretation by Gudel et al. that the source of the anomalous X-Ray and radio flux is a very close, chromospherically active solar-type companion. This work was supported by NASA/AURA grant GO-06691 for HST and NSF grant AST94-17035.

  3. Photometry Transforms Generation with PTGP (Abstract)

    NASA Astrophysics Data System (ADS)

    Myers, G.; Menzies, K.; Silvis, G.; Harris, B.

    2015-06-01

    (Abstract only) Historically the development of photometry transformation coefficients required extensive manual effort and the use of large spreadsheets. A new release—version 5.0—of the Photometry Transformations Generation Program (PTGP) achieves the goal of generating transformation coefficients without the use of spreadsheets—saving considerable time and ensuring data accuracy. PTGP version 5.0 works directly with VSP to retrieve the most recent standard star reference magnitudes (currently for M67 and NGC7790). It then processes instrument magnitude file(s) downloaded from vphot or exported from AIP4WIN or MAXIM. Either AUID or “Boulder” star identifications can be used for AIP4WIN and MAXIM. When using VPHOT data or “Boulder” star identifications, PTGP determines the AUID names for each of the reference standard stars. All standard transforms are calculated. Plots of each transform's data can be reviewed, and individual star observations added/deleted. Transform sets can be saved for further use. Transform sets can be compared and selected sets averaged. The averaged sets can be exported in a file format compatible with the AAVSO TA tool. The presentation will provide a brief overview and demonstration of the tool. It will also discuss the implications of using PYTHON for the development—both benefits and potential problems. The program runs on both PCs and Macs. A subsequent presentation will discuss the use of VPHOT and PTGP to generate transforms and the testing of the impacts of varying key VPHOT and PTGP parameters.

  4. Factors affecting survival of Shigatoxin-producing Escherichia coli on abiotic surfaces.

    PubMed

    Mretr, T; Heir, E; Mo, K R; Habimana, O; Abdelgani, A; Langsrud, S

    2010-03-31

    Shigatoxin-producing Escherichia coli (STEC) causes severe infections, and has been the cause of a number of foodborne outbreaks. Knowledge on the survival of STEC is crucial in order to limit the risk of cross contamination and transfer of STEC to food during processing. In this study survival of STEC and non-STEC on surfaces under various humidities, temperatures and in the presence of different types of soil was investigated. A model system with controlled relative humidity and temperature was established by using saturated salt solutions. All the 12 STEC strains had a reduction in viable count during incubation at 70% RH at 12 degrees C. The reduction was 2-3.5 log and 4.5-5.5 log after 1 and 7 days of incubation, respectively. Surviving cells were observed after 19 days of incubation. The STEC strains were more resistant to desiccation than non-STEC strains. STEC survived better at 12 degrees C, compared to 20 degrees C. The survival of STEC was much lower than the survival of a Staphylococcus simulans strain tested, which showed less than 1 log reduction until day 7 at 70% RH at 12 degrees C, while several STEC strains had comparable survival to a Salmonella Agona strain. The survival of two STEC strains tested was highest at 98% RH. The lowest survival was observed at 85% RH, with better survival at drier conditions. Presence of proteins and glucose protected the cells at dry conditions. Two commercial disinfectants tested at in-use concentration had limited effect (0.8-2.5 log reduction) against STEC on stainless steel, especially for cells incubated at high relative humidity (98% RH). STEC surviving on surfaces in the food industry may impose a risk for cross contamination. Cleaning and use of suitable disinfectants will reduce the survival of STEC, but surfaces should be allowed to dry completely since humid conditions will promote the survival and growth of STEC. PMID:20100628

  5. Pilot investigations of surface parts of three closed landfills and factors affecting them.

    PubMed

    Saarela, Jouko

    2003-05-01

    Aftercare of closed sanitary landfills in a major environmental problem. Rehabilitation of the landfill with vegetation and reducing leachate production are two issues that must be dealt. For this reason, Finnish Environment Institute has conducted several projects on closed landfills. This research aims at determining the physical and chemical properties of the soils at three closed landfills in Helsinki, Finland. Research was conducted to understand the impact by studying the following properties: Chemical, nutrient metal, gamma and radon analysis of surface soils of three closed landfills in Helsinki area. PMID:12733818

  6. A new capture fraction method to map how pumpage affects surface water flow

    USGS Publications Warehouse

    Leake, S.A.; Reeves, H.W.; Dickinson, J.E.

    2010-01-01

    All groundwater pumped is balanced by removal of water somewhere, initially from storage in the aquifer and later from capture in the form of increase in recharge and decrease in discharge. Capture that results in a loss of water in streams, rivers, and wetlands now is a concern in many parts of the United States. Hydrologists commonly use analytical and numerical approaches to study temporal variations in sources of water to wells for select points of interest. Much can be learned about coupled surface/groundwater systems, however, by looking at the spatial distribution of theoretical capture for select times of interest. Development of maps of capture requires (1) a reasonably well-constructed transient or steady state model of an aquifer with head-dependent flow boundaries representing surface water features or evapotranspiration and (2) an automated procedure to run the model repeatedly and extract results, each time with a well in a different location. This paper presents new methods for simulating and mapping capture using three-dimensional groundwater flow models and presents examples from Arizona, Oregon, and Michigan. Journal compilation ?? 2010 National Ground Water Association. No claim to original US government works.

  7. Factors Affecting P Loads to Surface Waters: Comparing the Roles of Precipitation and Land Management Practices

    NASA Astrophysics Data System (ADS)

    Motew, M.; Booth, E.; Carpenter, S. R.; Kucharik, C. J.

    2014-12-01

    Surface water quality is a major concern in the Yahara watershed (YW) of southern Wisconsin, home to a thriving dairy industry, the city of Madison, and five highly valued lakes that are eutrophic. Despite management interventions to mitigate runoff, there has been no significant trend in P loading to the lakes since 1975. Increases in manure production and heavy rainfall events over this time period may have offset any effects of management. We developed a comprehensive, integrated modeling framework that can simulate the effects of multiple drivers on ecosystem services, including surface water quality. The framework includes process-based representation of terrestrial ecosystems (Agro-IBIS) and groundwater flow (MODFLOW), hydrologic routing of water and nutrients across the landscape (THMB), and assessment of lake water quality (YWQM). Biogeochemical cycling and hydrologic transport of P have been added to the framework to enable detailed simulation of P dynamics within the watershed, including interactions with climate and management. The P module features in-soil cycling of organic, inorganic, and labile forms of P; manure application, decomposition, and subsequent loss of dissolved P in runoff; loss of particulate-bound P with erosion; and transport of dissolved and particulate P within waterways. Model results will compare the effects of increased heavy rainfall events, increased manure production, and implementation of best management practices on P loads to the Yahara lakes.

  8. A surface-exposed neuraminidase affects complement resistance and virulence of the oral spirochete Treponema denticola

    PubMed Central

    Kurniyati, Kurni; Zhang, Weiyan; Zhang, Kai; Li, Chunhao

    2013-01-01

    Neuraminidases (sialidases) catalyze the removal of terminal sialic acid from glycoconjugates. Bacterial pathogens often utilize neuraminidases to scavenge host sialic acid, which can be utilized either as a nutrient or as a decorating molecule to disguise themselves from host immune attacks. Herein, a putative neuraminidase (TDE0471) was identified in Treponema denticola, an oral spirochete associated with human periodontitis. TDE0471 is a cell surface-exposed exo-neuraminidase that removes sialic acid from human serum proteins; it is required for T. denticola to grow in a medium that mimics gingival crevice fluid, suggesting that the spirochete may use sialic acid as a nutrient in vivo. TDE0471 protects T. denticola from serum killing by preventing the deposition of membrane attack complexes on the bacterial cell surface. Animal studies revealed that a TDE0471-deficient mutant is less virulent than its parental wild-type strain in BALB/C mice. However, it causes a level of tissue damage similar to the wild type in complement-deficient B6.129S4-C3tm1Crr/J mice albeit the damage caused by both bacterial strains is more severe in these transgenic mice. Based on these results, we propose that T. denticola has evolved a strategy to scavenge host sialic acid using its neuraminidase, which allows the spirochete to acquire nutrients and evade complement killing. PMID:23808705

  9. N-acetyl-L-cysteine affects growth, extracellular polysaccharide production, and bacterial biofilm formation on solid surfaces.

    PubMed

    Olofsson, Ann-Cathrin; Hermansson, Malte; Elwing, Hans

    2003-08-01

    N-Acetyl-L-cysteine (NAC) is used in medical treatment of patients with chronic bronchitis. The positive effects of NAC treatment have primarily been attributed to the mucus-dissolving properties of NAC, as well as its ability to decrease biofilm formation, which reduces bacterial infections. Our results suggest that NAC also may be an interesting candidate for use as an agent to reduce and prevent biofilm formation on stainless steel surfaces in environments typical of paper mill plants. Using 10 different bacterial strains isolated from a paper mill, we found that the mode of action of NAC is chemical, as well as biological, in the case of bacterial adhesion to stainless steel surfaces. The initial adhesion of bacteria is dependent on the wettability of the substratum. NAC was shown to bind to stainless steel, increasing the wettability of the surface. Moreover, NAC decreased bacterial adhesion and even detached bacteria that were adhering to stainless steel surfaces. Growth of various bacteria, as monocultures or in a multispecies community, was inhibited at different concentrations of NAC. We also found that there was no detectable degradation of extracellular polysaccharides (EPS) by NAC, indicating that NAC reduced the production of EPS, in most bacteria tested, even at concentrations at which growth was not affected. Altogether, the presence of NAC changes the texture of the biofilm formed and makes NAC an interesting candidate for use as a general inhibitor of formation of bacterial biofilms on stainless steel surfaces. PMID:12902275

  10. Dynamitin affects cell-surface expression of voltage-gated sodium channel Nav1.5.

    PubMed

    Chatin, Benoît; Colombier, Pauline; Gamblin, Anne Laure; Allouis, Marie; Le Bouffant, Françoise

    2014-11-01

    The major cardiac voltage-gated sodium channel Nav1.5 associates with proteins that regulate its biosynthesis, localization, activity and degradation. Identification of partner proteins is crucial for a better understanding of the channel regulation. Using a yeast two-hybrid screen, we identified dynamitin as a Nav1.5-interacting protein. Dynamitin is part of the microtubule-binding multiprotein complex dynactin. When overexpressed it is a potent inhibitor of dynein/kinesin-mediated transport along the microtubules by disrupting the dynactin complex and dissociating cargoes from microtubules. The use of deletion constructs showed that the C-terminal domain of dynamitin is essential for binding to the first intracellular interdomain of Nav1.5. Co-immunoprecipitation assays confirmed the association between Nav1.5 and dynamitin in mouse heart extracts. Immunostaining experiments showed that dynamitin and Nav1.5 co-localize at intercalated discs of mouse cardiomyocytes. The whole-cell patch-clamp technique was applied to test the functional link between Nav1.5 and dynamitin. Dynamitin overexpression in HEK-293 (human embryonic kidney 293) cells expressing Nav1.5 resulted in a decrease in sodium current density in the membrane with no modification of the channel-gating properties. Biotinylation experiments produced similar information with a reduction in Nav1.5 at the cell surface when dynactin-dependent transport was inhibited. The present study strongly suggests that dynamitin is involved in the regulation of Nav1.5 cell-surface density. PMID:25088759

  11. Do particle size and surface functionality affect uptake and depuration of gold nanoparticles by aquatic invertebrates?

    PubMed

    Park, Sujung; Woodhall, James; Ma, Guibin; Veinot, Jonathan G C; Boxall, Alistair B A

    2015-04-01

    Because of the widespread use of engineered nanoparticles (ENPs) in consumer and industrial products, it is inevitable that these materials will enter the environment. It is often stated that the uptake of ENPs into organisms in the environment is related to the particle size and surface functionality. To test this assumption, the present study investigated the uptake and depuration of gold nanoparticle (Au NPs) coated with either citrate (Au-citrate NPs), mercaptoundecanoic acid (Au-MUDA NPs), amino polyethylene glycol (PEG) thiol (Au-NH2 NPs), or PEG (Au-PEG NP) by the aquatic invertebrate Gammarus pulex. The studies were performed using a range of standard ecotoxicity media and natural waters, resulting in varying degrees of aggregation of the different NPs. Uptake of gold by G. pulex varied depending on the surface coatings, with Au-MUDA and Au-citrate NPs being taken up to a greater extent than Au-NH2 and Au-PEG NPs in all test media and natural waters. In all test media evaluated, higher amounts of amino and PEG-coated ENPs were eliminated compared with MUDA- and citrate-coated ENPs. No obvious relationships were seen between the aggregation state of the different Au NPs in treatment and uptake, suggesting that the widely accepted assumption that Au NP uptake is related to particle size does not hold for the range of aggregation states studied (67.1-178.8 nm). Positive correlations between particle number concentration in the media and uptake were observed, indicating that this factor might partly explain the differences in uptake of a particle from different media types. PMID:25556899

  12. Plasma of Argon Affects the Earliest Biological Response of Different Implant Surfaces: An In Vitro Comparative Study.

    PubMed

    Canullo, L; Genova, T; Tallarico, M; Gautier, G; Mussano, F; Botticelli, D

    2016-05-01

    The aim of this in vitro study was to evaluate the early cell response and protein adsorption elicited by the argon plasma treatment of different commercially available titanium surfaces via a chair-side device. Sterile disks made of grade 4 titanium (n= 450, 4-mm diameter) with 3 surface topographies (machined, plasma sprayed, and zirconia blasted and acid etched) were allocated to receive 4 testing treatments (2% and 10% protein adsorption and cell adhesion with MC3T3-E1 and MG-63). Furthermore, the specimens were divided to undergo 1) argon plasma treatment (10 W, 1 bar for 12 min) in a plasma reactor, 2) ultraviolet (UV) light treatment for 2 h (positive control group), or 3) no treatment (control group). Pretreatment surface analyses based on a scanning electron microscope and profilometer images were also performed. Profilometric analysis demonstrated that the evaluated specimens perfectly suit the standard parameters. The use of argon plasma was capable of affecting the quantity of proteins adsorbed on the different surfaces, notwithstanding their roughness or topographic features at a low fetal bovine serum concentration (2%). UV light treatment for 2 h attained similar results. Moreover, both the plasma of argon and the UV light demonstrated a significant increase in the number of osteoblasts adherent at 10 min in all tested surfaces. Within its limitations, this in vitro study highlights the potential biological benefits of treating implant surfaces with plasma of argon or UV, irrespective of the roughness of the titanium surface. However, in vivo experiments are needed to confirm these preliminary data and settle the rationale of a treatment that might be clinically relevant in case of bone-reparative deficiencies. PMID:26848069

  13. Restoration and Photometry of Full-Disk Solar Images

    NASA Astrophysics Data System (ADS)

    Walton, Stephen R.; Preminger, Dora G.

    1999-04-01

    Daily, photometric, full-disk digital solar images have been taken at the San Fernando Observatory (SFO) in several wavelengths for more than 10 years. This work describes a project to evaluate and remove the effects of scattered light from the images, while preserving the photometry. We model both the solar limb and the point-spread function analytically, and the algorithm uses a least-squares fitting technique that does not require artificial extension of the data. Image restoration is carried out using standard techniques, with the exception of a method for estimating a non-white noise component. We show using artificial solar images with ``sunspots'' and ``faculae'' that the effects of blurring are greater near the solar limb, but that the restorations recover most of the actual contrast of surface features. Images taken with two different telescopes, after restoration, show surface feature contrasts that are in better agreement than before the restoration. In addition, the measured umbral contrast of approximately -90% on restored images at 6723 Å is the expected contrast value for umbral temperatures near 3000 K. Modeling of the solar irradiance using restored images instead of the original images from a 3 month period in 1988 shows no advantage if we use variations in sunspot deficit and facular excess to model irradiance variations. However, a new parameter, the model total irradiance derived from restored broadband red images, can model the actual solar irradiance during this period with an R2 value of 0.96.

  14. New Insights into Stellar Astrophysics from High-Precision Photometry

    NASA Astrophysics Data System (ADS)

    Soderblom, David R.

    2013-01-01

    The rich harvest of information on the occurrence and nature of planets around solar-type stars is why Kepler was built, but equally profound from this mission are the insights and quantitative physical studies of stars. The Kepler sample is dominated by the ~100,000 stars that are like the Sun, yet the Kepler field includes examples of nearly every stellar type. Kepler's exquisite photometry - continuously over an extended time - has enabled the detection of new phenomena and has provided critical tests of stellar models. In this brief review I will summarize some of the exciting new findings that Kepler has made possible, including: Stellar surface granulation in late-type stars; Evidence for rapid rotation of the cores of some evolved stars; Flares on G, K and M stars; Precise ages for older solar-type stars; Evidence for "mixed" modes in evolved stars that couple p-modes to interior g-modes; Stellar differential rotation; Detection of stellar activity cycles from asteroseismology; Mixing processes in stars; Detailed studies of eclipsing binaries; A comparison of the Sun to similar stars; Pulsating stars; Stellar surface features revealed by planet transits.

  15. Proliferation of Purple Sulphur Bacteria at the Sediment Surface Affects Intertidal Mat Diversity and Functionality

    PubMed Central

    Hubas, Cédric; Jesus, Bruno; Ruivo, Mickael; Meziane, Tarik; Thiney, Najet; Davoult, Dominique; Spilmont, Nicolas; Paterson, David M.; Jeanthon, Christian

    2013-01-01

    There is a relative absence of studies dealing with mats of purple sulphur bacteria in the intertidal zone. These bacteria display an array of metabolic pathways that allow them to disperse and develop under a wide variety of conditions, making these mats important in terms of ecosystem processes and functions. Mass blooms of purple sulphur bacteria develop during summer on sediments in the intertidal zone especially on macroalgal deposits. The microbial composition of different types of mats differentially affected by the development of purple sulphur bacteria was examined, at low tide, using a set of biochemical markers (fatty acids, pigments) and composition was assessed against their influence on ecosystem functions (sediment cohesiveness, CO2 fixation). We demonstrated that proliferation of purple sulphur bacteria has a major impact on intertidal mats diversity and functions. Indeed, assemblages dominated by purple sulphur bacteria (Chromatiaceae) were efficient exopolymer producers and their biostabilisation potential was significant. In addition, the massive growth of purple sulphur bacteria resulted in a net CO2 degassing whereas diatom dominated biofilms represented a net CO2 sink. PMID:24340018

  16. Proliferation of purple sulphur bacteria at the sediment surface affects intertidal mat diversity and functionality.

    PubMed

    Hubas, Cdric; Jesus, Bruno; Ruivo, Mickael; Meziane, Tarik; Thiney, Najet; Davoult, Dominique; Spilmont, Nicolas; Paterson, David M; Jeanthon, Christian

    2013-01-01

    There is a relative absence of studies dealing with mats of purple sulphur bacteria in the intertidal zone. These bacteria display an array of metabolic pathways that allow them to disperse and develop under a wide variety of conditions, making these mats important in terms of ecosystem processes and functions. Mass blooms of purple sulphur bacteria develop during summer on sediments in the intertidal zone especially on macroalgal deposits. The microbial composition of different types of mats differentially affected by the development of purple sulphur bacteria was examined, at low tide, using a set of biochemical markers (fatty acids, pigments) and composition was assessed against their influence on ecosystem functions (sediment cohesiveness, CO2 fixation). We demonstrated that proliferation of purple sulphur bacteria has a major impact on intertidal mats diversity and functions. Indeed, assemblages dominated by purple sulphur bacteria (Chromatiaceae) were efficient exopolymer producers and their biostabilisation potential was significant. In addition, the massive growth of purple sulphur bacteria resulted in a net CO2 degassing whereas diatom dominated biofilms represented a net CO2 sink. PMID:24340018

  17. Visual and Near-IR Photometry of Nova Del 2013

    NASA Astrophysics Data System (ADS)

    Gehrz, R. D.; Dykhoff, D. A.; Shenoy, D. P.

    2013-08-01

    We report Visual and Near-IR photometry of Nova Del 2013 taken at the University of Minnesota's O'Brien Observatory (Marine-on-St-Croix, Minnesota, USA). VRIJHKLM photometry were obtained on two successive nights using an AsSi bolometer. Vega (alpha Lyrae) was used as the standard star. Our photometry show: August 16.2 UT: V = 4.8 +/- 0.1, R = 5.4 +/- 0.1, I = 5.2 +/- 0.1, J = 4.4 +/- 0.1, H = 4.3 +/- 0.1, K = 4.3 +/- 0.1, L = 4.5 +/- 0.2.

  18. Characterization of extrasolar planetary atmospheres by thermal infrared photometry

    NASA Astrophysics Data System (ADS)

    Pierrehumbert, R.; Lloyd, J. P.

    2010-12-01

    Exoplanet observations offer the potential to study planetary atmospheres at stages of evolution not accessible in our own solar system. The detection of any atmosphere at all around an M-dwarf Super-Earth class planet would provide a powerful constraint on theories of atmospheric escape. We propose a method for detection and characterization of atmospheres through thermal infrared photometry. The method takes advantage of the changing infrared emission seen by a distant observer, caused by the variation in which part of the planet is viewed as it proceeds in its orbit. We focus on the novel issues presented by planets with a distinct surface. We present a catalog of thermal emission signatures pertinent to planets in close-orbits about M-dwarfs. Such planets are expected to be in tide-locked, quasi-synchronous spin states, or 3:2 spin-orbit resonances, and have a very hot spot under the subsolar point, and a very cold nightside, particularly when the atmosphere is thin or absent. When there is an atmosphere, the low Coriolis force makes heat transport very efficient, leading to an atmosphere that is horizontally isothermal. This behavior is familiar from the WTG approximation widely applied to the Earth's tropics, and we have verified by GCM simulations that it applies globally for planets in slow spin-states. When the atmosphere is optically thick in some parts of the thermal infrared, the dichotomy beween atmospheric and surface temperature contrasts leaves a characteristic imprint on the thermal emission time series. The figure illustrates the method for a tide-locked planet in a circular orbit, with stellar luminosity and semi-major axis similar to Gliese 581c. The orbit is viewed edge-on but transit effects are not shown. We show synthetic observations at two wavenumbers, for both an airless case and a case with an isothermal atmosphere. In the optically thick band, the the atmosphere shows up in the moderation of the photometry curve. We will also show signatures for planets in eccentric orbits and other spin states, and from simulations of partially ice-covered waterworlds. Typical ratios of planetary to stellar fluxes are on the order of ten ppm. For a system ten light-years distant, photon counts are on the order of 10 m-2s{-1]. Pertinent instrumental issues will be discussed

  19. Surface interactions affect the toxicity of engineered metal oxide nanoparticles toward Paramecium.

    PubMed

    Li, Kungang; Chen, Ying; Zhang, Wen; Pu, Zhichao; Jiang, Lin; Chen, Yongsheng

    2012-08-20

    To better understand the potential impacts of engineered metal oxide nanoparticles (NPs) in the ecosystem, we investigated the acute toxicity of seven different types of engineered metal oxide NPs against Paramecium multimicronucleatum, a ciliated protozoan, using the 48 h LC(50) (lethal concentration, 50%) test. Our results showed that the 48 h LC(50) values of these NPs to Paramecium ranged from 0.81 (Fe(2)O(3) NPs) to 9269 mg/L (Al(2)O(3) NPs); their toxicity to Paramecium increased as follows: Al(2)O(3) < TiO(2) < CeO(2) < ZnO < SiO(2) < CuO < Fe(2)O(3) NPs. On the basis of the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, interfacial interactions between NPs and cell membrane were evaluated, and the magnitude of interaction energy barrier correlated well with the 48 h LC(50) data of NPs to Paramecium; this implies that metal oxide NPs with strong association with the cell surface might induce more severe cytotoxicity in unicellular organisms. PMID:22693953

  20. How does the spaceborne radar blind zone affect derived surface snowfall statistics in polar regions?

    NASA Astrophysics Data System (ADS)

    Maahn, Maximilian; Burgard, Clara; Crewell, Susanne; Gorodetskaya, Irina V.; Kneifel, Stefan; Lhermitte, Stef; Van Tricht, Kristof; Lipzig, Nicole P. M.

    2014-12-01

    Global statistics of snowfall are currently only available from the CloudSat satellite. But CloudSat cannot provide observations of clouds and precipitation within the so-called blind zone, which is caused by ground-clutter contamination of the CloudSat radar and covers the last 1200 m above land/ice surface. In this study, the impact of the blind zone of CloudSat on derived snowfall statistics in polar regions is investigated by analyzing three 12 month data sets recorded by ground-based Micro Rain Radar (MRR) at the Belgian Princess Elisabeth station in East Antarctica and at Ny-Ålesund and Longyearbyen in Svalbard, Norway. MRR radar reflectivity profiles are investigated in respect to vertical variability in the frequency distribution, changes in the number of observed snow events, and impacts on total precipitation. Results show that the blind zone leads to reflectivity being underestimated by up to 1 dB, the number of events being altered by ±5% and the precipitation amount being underestimated by 9 to 11 percentage points. Besides investigating a blind zone of 1200 m, the impacts of a reduced blind zone of 600 m are also analyzed. This analysis will help in assessing future missions with a smaller blind zone. The reduced blind zone leads to improved representation of mean reflectivity but does not improve the bias in event numbers and precipitation amount.

  1. Experiences with Opto-Mechanical Systems that Affect Optical Surfaces at the Sub-Nanometer Level

    SciTech Connect

    Hale, L C; Taylor, J S

    2008-04-03

    Projection optical systems built for Extreme Ultraviolet Lithography (EUVL) demonstrated the ability to produce, support and position reflective optical surfaces for achieving transmitted wavefront errors of 1 nm or less. Principal challenges included optical interferometry, optical manufacturing processes, multi-layer coating technology and opto mechanics. Our group was responsible for designing, building and aligning two different projection optical systems: a full-field, 0.1 NA, four-mirror system for 70 nm features and a small-field, 0.3 NA, two-mirror system for 30 nm features. Other than physical size and configuration, the two systems were very similar in the way they were designed, built and aligned. A key difference exists in the optic mounts, driven primarily by constraints from the metrology equipment used by different optics manufacturers. As mechanical stability and deterministic position control of optics will continue to play an essential role in future systems, we focus our discussion on opto-mechanics and primarily the optic mounts.

  2. How do silanes affect the lubricating properties of cationic double chain surfactant on silica surfaces?

    PubMed

    Beauvais, Muriel; Serreau, Laurence; Heitz, Caroline; Barthel, Etienne

    2009-03-01

    The effect of an aminosilane on the lubricant properties of a C(18) double-chained cationic surfactant has been investigated in the context of glass fiber forming process. The surfactant adsorption was studied on silica by Fourier transform infrared (FT-IR) spectroscopy in the attenuated total reflexion (ATR) mode as a function of the aminosilane concentration in an organic water based formulation (sizing) used to coat the glass fibers during the process. A reciprocating ball-on-plate tribometer was used to compare friction properties of silica in contact with the aminosilane-surfactant mixture and in presence of each component of the sizing. Surface forces were measured between silica and an atomic force microscope (AFM) silicon nitride tip in the sizing and in the pure cationic surfactant solution. The aminosilane on its own has no lubricant property and reduces or even suppresses the cationic surfactant adsorption on silica. However, the silica-silica contact is lubricated even if the infrared spectroscopy does not detect any surfactant adsorption. The repeated contacts and shear due to the friction experiment itself induce accumulation, organization and compactness of surfactant bilayers. PMID:19059599

  3. Water chemistry of surface waters affected by the Fourmile Canyon wildfire, Colorado, 2010-2011

    USGS Publications Warehouse

    McCleskey, R. Blaine; Writer, Jeffrey H.; Murphy, Sheila F.

    2012-01-01

    In September 2010, the Fourmile Canyon fire burned about 23 percent of the Fourmile Creek watershed in Boulder County, Colo. Water-quality sampling of Fourmile Creek began within a month after the wildfire to assess its effects on surface-water chemistry. Water samples were collected from five sites along Fourmile Creek (above, within, and below the burned area) monthly during base flow, twice weekly during snowmelt runoff, and at higher frequencies during storm events. Stream discharge was also monitored. Water-quality samples were collected less frequently from an additional 6 sites on Fourmile Creek, from 11 tributaries or other inputs, and from 3 sites along Boulder Creek. The pH, electrical conductivity, temperature, specific ultraviolet absorbance, total suspended solids, and concentrations (dissolved and total) of major cations (calcium, magnesium, sodium, and potassium), anions (chloride, sulfate, alkalinity, fluoride, and bromide), nutrients (nitrate, ammonium, and phosphorus), trace metals (aluminum, arsenic, boron, barium, beryllium, cadmium, cobalt, chromium, copper, iron, mercury, lithium, manganese, molybdenum, nickel, lead, rubidium, antimony, selenium, strontium, vanadium, and zinc), and dissolved organic carbon are here reported for 436 samples collected during 2010 and 2011.

  4. Sea surface temperature fronts affect distribution of Pacific saury (Cololabis saira) in the Northwestern Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Tseng, Chen-Te; Sun, Chi-Lu; Belkin, Igor M.; Yeh, Su-Zan; Kuo, Chin-Lau; Liu, Don-Chung

    2014-09-01

    Pacific saury (Cololabis saira) is an important fisheries resource and commercial species of Taiwanese deep-sea saury stick-held dip net fishery in the Northwestern Pacific Ocean. In this study, the logbook data of a 3-year (2006-2008) Taiwanese Pacific saury fishery and corresponding satellite-derived MODIS sea surface temperature (SST) data were analyzed to detect SST fronts and examine their influence on the spatio-temporal distribution of Pacific saury. The fronts were identified by the Cayula-Cornillon single-image edge detection algorithm. The results show that low frequency of SST fronts is associated with lower CPUEs during the early fishing season (June-August), while high frequency of SST fronts is associated with higher CPUEs during the peak fishing season. When fishing locations of Pacific saury are close to the SST fronts, higher CPUEs are observed. Results of this study provide a better understanding of how SST fronts influence distribution of Pacific saury and improve the basis of fishing ground forecasting.

  5. Affecting the morphology of silver deposition on carbon nanotube surface: from nanoparticles to dendritic (tree-like) nanostructures.

    PubMed

    Forati-Nezhad, Mohsen; Mir Mohamad Sadeghi, Gity; Yaghmaie, Frank; Alimohammadi, Farbod

    2015-01-01

    Chemical reduction was used to synthesize silver crystals on the surface of multiwall carbon nanotubes (MWCNTs) in the presence of acetone, N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone, and isopropyl alcohol as solvent. DMF and sodium dodecyl sulfate were used as a reducing and a stabilizing agent, respectively. The structure and nature of hybrid MWCNT/silver were characterized by Raman spectroscopy, FTIR spectroscopy, transmission electron microscopy (TEM), and field emission scanning electron microscope (FESEM). The presence of silver crystals on the nanotubes was confirmed by XRD. The results show the formation of silver crystals on the MWCNT surface and indicate that the morphology of silver crystals can be control by changing the solvent. The type of solvent is an effective parameter that affects the particle size and morphological transition from nanoparticles to silver trees. PMID:25491982

  6. Erosive cola-based drinks affect the bonding to enamel surface: an in vitro study

    PubMed Central

    CASAS-APAYCO, Leslie Caroll; DREIBI, Vanessa Manzini; HIPÓLITO, Ana Carolina; GRAEFF, Márcia Sirlene Zardin; RIOS, Daniela; MAGALHÃES, Ana Carolina; BUZALAF, Marília Afonso Rabelo; WANG, Linda

    2014-01-01

    Objective This study aimed to assess the impact of in vitro erosion provoked by different cola-based drinks (Coke types), associated or not with toothbrushing, to bonding to enamel. Material and Methods Fifty-six bovine enamel specimens were prepared and randomly assigned into seven groups (N=8): C- Control (neither eroded nor abraded), ERO-RC: 3x/1-minute immersion in Regular Coke (RC), ERO-LC: 3x/1-minute immersion in Light Coke (LC), ERO-ZC: 3x/1-minute immersion in Zero Coke (ZC) and three other eroded groups, subsequently abraded for 1-minute toothbrushing (EROAB-RC, EROAB-LC and EROAB-ZC, respectively). After challenges, they were stored overnight in artificial saliva for a total of 24 hours and restored with Adper Single Bond 2/Filtek Z350. Buildup coronal surfaces were cut in 1 mm2 -specimens and subjected to a microtensile test. Data were statistically analyzed by two-way ANOVA/Bonferroni tests (α=0.05). Failure modes were assessed by optical microscopy (X40). The interface of the restorations were observed using Confocal Laser Scanning Microscopy (CLSM). Results All tested cola-based drinks significantly reduced the bond strength, which was also observed in the analyses of interfaces. Toothbrushing did not have any impact on the bond strength. CLSM showed that except for Zero Coke, all eroded specimens resulted in irregular hybrid layer formation. Conclusions All cola-based drinks reduced the bond strength. Different patterns of hybrid layers were obtained revealing their impact, except for ZC. PMID:24918663

  7. Millimagnitude photometry for transiting exoplanets candidates

    NASA Astrophysics Data System (ADS)

    Miranda, S. H.; Ramírez, S.; Minniti, D.; Ivanov, V. D.; Pietrzynski, G.

    2009-05-01

    We present precise new V, I, and K-band photometry for the planetary transit candidate star OGLE-TR-82. Good seeing V-band images acquired with the VIMOS instrument at ESO Very Large Telescope (VLT) allowed us to measure V = 20.6+/-0.03 mag star in spite of the presence of a brighter neighbour about 1'' away. This faint magnitude answers the question why it has not been possible to measure radial velocities for this object. One transit of this star has been observed with the GMOS-S instrument of GEMINI-South telescope in the i and g-bands. The measurement of the transit allows us to verify that this is not a false positive, to confirm the transit amplitude measured by OGLE, and to improve the ephemeris. The transit is well defined in the i-band light curve, with a depth of A_i=0.034 mag. It is less well defined, but deeper (A_g=0.1 mag) in the g-band, in which the star is significantly fainter. The near-infrared photometry obtained with the SOFI array at the ESO New Technology Telescope (NTT) yields K = 12.2+/-0.1, and V - K = 8.4+/-0.1, so red that it is unlike any other transit candidate studied before. Due to the extreme nature of this object, we have not yet been able to measure velocities for this star, but based on the new data we consider two different possible configurations: (1) a nearby M7V star, or (2) a blend with a very reddened distant red giant. The nearby M7V dwarf hypothesis would give a radius for the companion of R_p = 0.3+/-0.1 R_J, i.e. the size of Neptune. Near-IR spectroscopy finally shows that OGLE-TR-82 is a distant, reddened giant of spectral type K3III, with A_V=6. Therefore, we discard the planetary nature of the companion. We conclude that this system is a main-sequence binary blended with a background red giant.

  8. Detection of Extrasolar Planets by Transit Photometry

    NASA Technical Reports Server (NTRS)

    Borucki, William; Koch, David; Webster, Larry; Dunham, Edward; Witteborn, Fred; Jenkins, Jon; Caldwell, Douglas; Showen, Robert; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    A knowledge of other planetary systems that includes information on the number, size, mass, and spacing of the planets around a variety of star types is needed to deepen our understanding of planetary system formation and processes that give rise to their final configurations. Recent discoveries show that many planetary systems are quite different from the solar system in that they often possess giant planets in short period orbits. The inferred evolution of these planets and their orbital characteristics imply the absence of Earth-like planets near the habitable zone. Information on the properties of the giant-inner planets is now being obtained by both the Doppler velocity and the transit photometry techniques. The combination of the two techniques provides the mass, size, and density of the planets. For the planet orbiting star HD209458, transit photometry provided the first independent confirmation and measurement of the diameter of an extrasolar planet. The observations indicate a planet 1.27 the diameter of Jupiter with 0.63 of its mass (Charbonneau et al. 1999). The results are in excellent agreement with the theory of planetary atmospheres for a planet of the indicated mass and distance from a solar-like star. The observation of the November 23, 1999 transit of that planet made by the Ames Vulcan photometer at Lick Observatory is presented. In the future, the combination of the two techniques will greatly increase the number of discoveries and the richness of the science yield. Small rocky planets at orbital distances from 0.9 to 1.2 AU are more likely to harbor life than the gas giant planets that are now being discovered. However, new technology is needed to find smaller, Earth-like planets, which are about three hundred times less massive than Jupiter-like planets. The Kepler project is a space craft mission designed to discover hundreds of Earth-size planets in and near the habitable zone around a wide variety of stars. To demonstrate that the technology exists to find such small planets, our group has conducted an end-to-end system test. The results of the laboratory tests are presented and show that we are ready to start the search for Earth-size planets.

  9. Polarimetric Retrievals of Surface and Aerosol Properties in the Region Affected by the Deepwater Horizon Oil Spill

    NASA Astrophysics Data System (ADS)

    Ottaviani, M.; Cairns, B.; Chowdhary, J.; Knobelspiesse, K. D.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Rogers, R.; Obland, M. D.; Zhai, P.; Hu, Y.

    2010-12-01

    In July 2010, the Research Scanning Polarimeter (RSP) effectuated two flights in two consecutive days over the region affected by the oil spill of the Deepwater Horizon offshore platform. Integrated on the NASA Langley B-200 aircraft, the instrument is deployed together with the High Spectral Resolution Lidar (HSRL), which provides information on the distribution of the aerosol layers beneath the aircraft including an accurate estimate of aerosol optical depth. We present a sensitivity study to illustrate the merits of polarization measurements in detecting variations of ocean surface properties linked to the presence of an oil slick. In particular, the Degree of Linear Polarization (DoLP) in the glint region does not depend on the surface roughness, while is severely affected by variations in the refractive index of the ocean surface. Exploiting the RSP channel at 2250nm, where virtually all the signal is generated by the Fresnel reflection at the surface, the DoLP at any angle well into the glint region can therefore be used to detect alterations in the ocean surface. More specifically, the glint profile at this wavelength is fitted to the Cox-Munk model with a routine which can optimally estimate wind speed and direction, while taking into account aircraft attitude variations in determining the viewing geometry. The surveyed area also presents a complex mix of aerosol types. At least one major urban layer originating in the US Southeast mixes in the central portion of the flight trajectory with smoke caused by controlled burns around the damaged platform. The constrain on surface reflectance provided by the SWIR RSP channel, together with the aerosol optical depth provided by the HSRL, are used in Radiative Transfer computations to model the channels at shorter wavelengths and retrieve aerosol descriptive parameters such as aerosol size distribution and refractive index. Finally, the presence of smoke is ground for a discussion on the possibility to infer aerosol absorption. In this respect, RSP retrieval can be aided by the HSRL unique capability of measuring aerosol extinction and backscatter independently.

  10. Voyager photometry of Triton - Haze and surface photometric properties

    NASA Technical Reports Server (NTRS)

    Hillier, J.; Helfenstein, P.; Verbiscer, A.; Veverka, J.

    1991-01-01

    The Voyager whole-disk observations of Triton at 0.41, 0.48, and 0.56 micron filter wavelengths are analyzed using a model which combines an improved version of Hapke's photometric equation with a thin atmospheric haze layer in the appropriate spherical geometry. The model is shown to describe accurately the phase curves over a range of phase angles and to agree with disk-resolved brightness scans along the photometric equator and mirror meridian. According to the model, the photometric parameters of Triton's regolith are reasonably typical of icy satellites, except for the extremely high (close to unity) single-scattering albedo.

  11. WIYN Open Cluster Study: UBVRI Photometry of NGC 2158

    NASA Astrophysics Data System (ADS)

    Taverne, Luke T.; Steinhauer, Aaron J.; Deliyannis, Constantine P.

    2015-01-01

    We present WIYN 0.9m HDI UBVRI photometry of NGC 2158, a very rich, intermediate-aged, open cluster located near the galactic anti-center. We report derived values for the cluster age, distance, reddening.

  12. Mg2+ binds to the surface of thymidylate synthase and affects hydride transfer at the interior active site

    PubMed Central

    Wang, Zhen; Sapienza, Paul J.; Abeysinghe, Thelma; Luzum, Calvin; Lee, Andrew L.; Finer-Moore, Janet S.; Stroud, Robert M.; Kohen, Amnon

    2013-01-01

    Thymidylate synthase (TSase) produces the sole intracellular de novo source of thymidine (i.e. the DNA base T) and thus is a common target for antibiotic and anticancer drugs. Mg2+ has been reported to affect TSase activity, but the mechanism of this interaction has not been investigated. Here we show that Mg2+ binds to the surface of Escherichia coli TSase and affects the kinetics of hydride transfer at the interior active site (16 Å away). Examination of the crystal structures identifies a Mg2+ near the glutamyl moiety of the folate cofactor, providing the first structural evidence for Mg2+ binding to TSase. The kinetics and NMR relaxation experiments suggest that the weak binding of Mg2+ to the protein surface stabilizes the closed conformation of the ternary enzyme complex and reduces the entropy of activation on the hydride transfer step. Mg2+ accelerates the hydride transfer by ca. 7-fold but does not affect the magnitude or temperature-dependence of the intrinsic kinetic isotope effect. These results suggest that Mg2+ facilitates the protein motions that bring the hydride donor and acceptor together, but it does not change the tunneling ready state of the hydride transfer. These findings highlight how variations in cellular Mg2+ concentration can modulate enzyme activity through long-range interactions in the protein, rather than binding at the active site. The interaction of Mg2+ with the glutamyl-tail of the folate cofactor and nonconserved residues of bacterial TSase may assist in designing antifolates with poly-glutamyl substitutes as species-specific antibiotic drugs. PMID:23611499

  13. Subglacial drainage of surface melt water affects ice motion: Application of a modeling study to West Greenland

    NASA Astrophysics Data System (ADS)

    Chu, W.; Creyts, T. T.; Bell, R. E.

    2013-12-01

    Subglacial hydrology is one of the main controlling factors in the spatial and temporal evolution of ice flow. The distribution of effective pressure and the form of subglacial drainage networks have important implications on basal sliding. However, subglacial melt water drainage is dynamic in space and time and varies in a complicated manner coupled to surface hydrology. Despite recent conceptual advances, relatively little is known about how the surface hydrology interacts with the subglacial drainage system and how it affects effective pressure and ice flow. Here, we build a 2D numerical model of subglacial drainage to investigate the coupling between drainage of surface melt water and glacier motion. A synthetic glacier geometry is used to obtain the steady-state solutions for effective pressure and subglacial conduit sizes on a rectangular grid. The model has channels and distributed linked cavities that occupy the grid centers and exchange water along the grid edges. The numerical procedure uses Newton's method to compute water pressure and conduit cross-sectional area. The water pressure solution is applied to a sliding law to calculate ice flow speed. We then applied the water model to a 6000 km2 catchment south of Jakobshavn Isbrae along the western margin of Greenland. The water model is forced with surface melt input from the Polar MM5 regional climate model. Surface melt is supplied at discrete locations through supraglacial lakes. The location of supraglacial lakes are identified from satellite imagery. We compare modeled output of ice speed to satellite derived measurements of ice flow and discuss their agreements and discrepancies.

  14. BVRI CCD photometry of Omega Centauri

    NASA Astrophysics Data System (ADS)

    Alcaino, Gonzalo; Liller, William

    1987-12-01

    The authors present the first CCD, BVRI main-sequence photometry for ω Cen, matched to the new BVRI isochrones of VandenBerg and Bell (1985). Their main conclusions are: (1) The main-sequence turnoffs as seen in the several colors are found to be at VTO = 18.3±0.15; the MSTO color indexes are at: B-V = 0.55±0.03, V-I = 0.73±0.03, and B-I = 1.28±0.03. (2) The magnitude difference between the main-sequence turnoff and the horizontal branch is ΔMV = 3.80±0.15, as derived from the color-magnitude diagrams. (3) The authors deduce a consistent age for ω Cen in all three color-magnitude diagrams of 17±1.5 Gyr. (4) The large scatter among the main-sequence stars demonstrates that the chemical inhomogeneity of about |Fe/H| = ≡1 dex persists as well in the unevolved stars, hence suggesting the composition to be primordial.

  15. Recent Advances in Video Meteor Photometry

    NASA Technical Reports Server (NTRS)

    Swift, Wesley R.; Suggs, Robert M.; Meachem, Terry; Cooke, William J.

    2003-01-01

    One of the most common (and obvious) problems with video meteor data involves the saturation of the output signal produced by bright meteors, resulting in the elimination of such meteors from photometric determinations. It is important to realize that a "bright" meteor recorded by intensified meteor camera is not what would be considered "bright" by a visual observer - indeed, many Generation II or III camera systems are saturated by meteors with a visual magnitude of 3, barely even noticeable to the untrained eye. As the relatively small fields of view (approx.30 ) of the camera systems captures at best modest numbers of meteors, even during storm peaks, the loss of meteors brighter than +3 renders the determination of shower population indices from video observations even more difficult. Considerable effort has been devoted by the authors to the study of the meteor camera systems employed during the Marshall Space Flight Center s Leonid ground-based campaigns, and a calibration scheme has been devised which can extend the useful dynamic range of such systems by approximately 4 magnitudes. The calibration setup involves only simple equipment, available to amateur and professional, and it is hoped that use of this technique will make for better meteor photometry, and move video meteor analysis beyond the realm of simple counts.

  16. BVI CCD photometry of 47 Tucanae

    SciTech Connect

    Alcaino, G.; Liller, W.

    1987-08-01

    CCD BVI main-sequence photometry of 47 Tuc is presented, matched to the recent BVI isochrones of VandenBerg and Bell (1985). The main-sequence turnoffs are found to be at V = 17.60 + or - 0.1, B-V = 0.56 + or - 0.02; V-I = 0.68 + or - 0.02, and B-I = 1.24 + or - 0.02. The magnitude difference between the main-sequence turnoff and the horizontal branch is 3.55 + or - 0.15 for all three color indices. A consistent age for 47 Tuc of 17 Gyr and a consistent distance modulus of (m-M)v = 13.2 are obtained for all three indices, and an absolute magnitude of Mv = 0.85 is determined for the horizontal branch stars. The results also favor the adoption of (Fe/H) near -0.5 as the best abundance value for 47 Tuc. 38 references.

  17. BVRI photometry of DQ Herculis in 2014

    NASA Astrophysics Data System (ADS)

    Dmitrienko, E. S.; Ibragimov, M. A.; Savanov, I. S.; Satovskii, B. L.; Egamberdiev, Sh. A.; Burkhanov, O. A.

    2015-09-01

    The results of BV RI photometry of the nova DQ Her 1934 performed at the Maidanak Observatory of the Astronomical Institute of the Uzbek Academy of Sciences in October 2014 are presented. The system's brightness, the out-of-eclipse color indices, and the shape of the minima in the BV RI light curves, which are due to eclipses of the white dwarf with its accreting disk-like envelope by the red dwarf, correspond to one of the lowest activity levels observed during the system's deepest relaxation after a nova outburst. The orbital-phase variations of the color indices indicate the presence of a considerably non-uniform brightness distribution for light coming from the disk-like envelope and other gaseous structures of DQ Her, which are observed at orbital phases of 0.85-1.15. The results can be qualitatively interpreted in a picture in which the gas flow structure is formed during mass exchange in an intermediate polar. The behavior found for the color indices could be due, for example, to the visibility in this phase interval of the passage of regions of shocks (tidal shocks, a hot line, and/or a detached shock) through the line of sight.

  18. Exoplanet Photometry of Tres-5b Using a DSLR Camera

    NASA Astrophysics Data System (ADS)

    Miller, Mike

    2015-05-01

    DSLR cameras are commonly used by amateur astronomers in the field of variable star photometry. After submitting photometry results to AAVSO using a DSLR camera for the past 4 years, I decided to see if it was possible to actually record magnitude drops of as little as 15 to 20 mmg as are seen in some exoplanet transits. Surprisingly, my results were much better than I expected. Clearly it is possible to get publishable results of exoplanet transits with a DSLR camera.

  19. BINARY STAR SYNTHETIC PHOTOMETRY AND DISTANCE DETERMINATION USING BINSYN

    SciTech Connect

    Linnell, Albert P.; DeStefano, Paul; Hubeny, Ivan E-mail: pdestefa@uw.edu

    2013-09-15

    This paper extends synthetic photometry to components of binary star systems. The paper demonstrates accurate recovery of single star photometric properties for four photometric standards, Vega, Sirius, GD153, and HD209458, ranging over the HR diagram, when their model synthetic spectra are placed in fictitious binary systems and subjected to synthetic photometry processing. Techniques for photometric distance determination have been validated for all four photometric standards.

  20. The expected Gaia revolution in asteroid science: Photometry and spectroscopy

    NASA Astrophysics Data System (ADS)

    Cellino, A.

    2014-07-01

    Gaia is expected to produce a major revolution in our knowledge of the asteroids. Apart from a huge improvement in the accuracy of the orbital elements of these objects, something which is a ''natural'' consequence of the unprecedented astrometric accuracy of Gaia, we can also expect that the photometric and spectrophotometric performances of the Gaia detectors will be such to substantially move ahead the frontier of the domain of physical characterization of asteroids by means of remote observations. A list of physical properties, that will be derived from the analysis of the detections corresponding to different observed transits of each object in the Gaia focal plane during five years of operational activity, includes masses, sizes, average densities, spin properties, reflectance spectra, albedos, as well as a new taxonomic classification. In this review, the focus will be on Gaia photometry and spectrophotometry. The method of photometric inversion of sparse photometric data developed to reduce Gaia photometric data of asteroids will be described, and its expected performances will be discussed. In particular, the choice of assuming for the objects the shapes of ideal triaxial ellipsoids, fairly simplistic in an era in which much more refined shape models are currently used in photometric inversion methods, will be justified by the need of minimizing the CPU time needed to process data for hundreds of thousands of objects in a reasonable time. The processing of spectrophotometric data will be also described. These data will produce a huge data set of reflectance spectra of asteroids. A particular advantage of these data will be that of including also the blue part of the spectrum, which has been substantially lost since the epoch in which the CCD detectors have replaced the older photomultipliers used for UBVRI photometry. The big data set of new asteroid spectra will be also used to develop a new asteroid taxonomy, used new algorithms developed for this purpose. Coupled with the determination of reasonably accurate masses and bulk densities for the biggest 100 asteroids, Gaia data will open a new era in asteroid science, and will allow us to answer some fundamental questions, including the relation between internal structure and surface properties. The resulting post-Gaia scenario in asteroid science will be very much improved with respect to the current state of the art.

  1. NEW UBVRI PHOTOMETRY OF 234 M33 STAR CLUSTERS

    SciTech Connect

    Ma Jun

    2013-04-15

    This is the second paper of our series. In this paper, we present UBVRI photometry for 234 star clusters in the field of M33. For most of these star clusters, there is photometry in only two bands in previous studies. The photometry of these star clusters is performed using archival images from the Local Group Galaxies Survey, which covers 0.8 deg{sup 2} along the major axis of M33. Detailed comparisons show that, in general, our photometry is consistent with previous measurements, and in particular that our photometry is in good agreement with that of Zloczewski and Kaluzny. Combined with star cluster photometry in previous studies, we present some results: none of the M33 youngest clusters ({approx}10{sup 7} yr) have masses approaching 10{sup 5} M{sub Sun }, and comparisons with models of simple stellar populations suggest a large range of ages for M33 star clusters and some as old as the Galactic globular clusters.

  2. FIXING THE U-BAND PHOTOMETRY OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Krisciunas, Kevin; Bastola, Deepak; Suntzeff, Nicholas B.; Espinoza, Juan; Gonzalez, David; Gonzalez, Luis; Gonzalez, Sergio; Hsiao, Eric Y.; Morrell, Nidia; Phillips, Mark M.; Hamuy, Mario E-mail: suntzeff@physics.tamu.edu E-mail: hsiao@lco.cl E-mail: mmp@lco.cl

    2013-01-01

    We present previously unpublished photometry of supernovae 2003gs and 2003hv. Using spectroscopically derived corrections to the U-band photometry, we reconcile U-band light curves made from imagery with the Cerro Tololo 0.9 m, 1.3 m, and Las Campanas 1 m telescopes. Previously, such light curves showed a 0.4 mag spread at one month after maximum light. This gives us hope that a set of corrected ultraviolet light curves of nearby objects can contribute to the full utilization of rest-frame U-band data of supernovae at redshift {approx}0.3-0.8. As pointed out recently by Kessler et al. in the context of the Sloan Digital Sky Survey supernova search, if we take the published U-band photometry of nearby Type Ia supernovae at face value, there is a 0.12 mag U-band anomaly in the distance moduli of higher redshift objects. This anomaly led the Sloan survey to eliminate from their analyses all photometry obtained in the rest-frame U-band. The Supernova Legacy Survey eliminated observer frame U-band photometry, which is to say nearby objects observed in the U-band, but they used photometry of high-redshift objects no matter in which band the photons were emitted.

  3. BRITE-Constellation: Nanosatellites for Precision Photometry of Bright Stars

    NASA Astrophysics Data System (ADS)

    Weiss, W. W.; Rucinski, S. M.; Moffat, A. F. J.; Schwarzenberg-Czerny, A.; Koudelka, O. F.; Grant, C. C.; Zee, R. E.; Kuschnig, R.; Mochnacki, St.; Matthews, J. M.; Orleanski, P.; Pamyatnykh, A.; Pigulski, A.; Alves, J.; Guedel, M.; Handler, G.; Wade, G. A.; Zwintz, K.

    2014-06-01

    BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is an international nanosatellite mission to monitor photometrically, in two colours, the brightness and temperature variations of stars generally brighter than mag(V) ≈ 4 with precision and time coverage not possible from the ground. The current mission design consists of six nanosats (hence Constellation): two from Austria, two from Canada, and two from Poland. Each 7 kg nanosat carries an optical telescope of aperture 3 cm feeding an uncooled CCD. One instrument in each pair is equipped with a blue filter; the other with a red filter. Each BRITE instrument has a wide field of view (≈24°), so up to about 15 bright stars can be observed simultaneously, sampled in 32 × 32 pixels sub-rasters. Photometry of additional fainter targets, with reduced precision but thorough time sampling, will be possible through onboard data processing. The BRITE sample is dominated by the most intrinsically luminous stars: massive stars seen at all evolutionary stages, and evolved medium-mass stars at the very end of their nuclear burning phases. The goals of BRITE-Constellation are to (1) measure p- and g-mode pulsations to probe the interiors and ages of stars through asteroseismology; (2) look for varying spots on the stars surfaces carried across the stellar disks by rotation, which are the sources of co-rotating interaction regions in the winds of the most luminous stars, probably arising from magnetic subsurface convection; and (3) search for planetary transits.

  4. A New Look at Photometry of the Moon

    NASA Astrophysics Data System (ADS)

    Goguen, Jay D.; Stone, T. C.; Kieffer, H. H.; Buratti, B. J.

    2010-10-01

    We test 2 very different models for light scattering by the lunar regolith: 1) TRLA - a Topographically Rough surface layer comprised of Low Albedo particles, and 2) RTE - a flat surface layer with the published size distribution and optical constants of Apollo soil particles, Mie calculation of the mean particle scattering matrix and rigorous solution of the Radiative Transfer Equation for all orders of scattering (Mishchenko et al 1999, JQRST 63, 409). For a typical lunar highland location (-17.21, 20.01), ROLO photometry (Kieffer & Stone 2005, Astron. J. 129, 2887) shows a distinct difference between the radiances measured before and after full moon (BFM, AFM) at the same 47.5 ± 2.5 degree phase angle, corresponding to incidence angles of 30 and 70 degrees, respectively. The TRLA model requires rms slopes of 34.1 ± 2.6 degrees to reproduce this BFM/AFM radiance difference, similar to previously published results. Analysis of Apollo ALSCC stereo images of in situ lunar regolith (Helfenstein and Shepard 1999, Icarus 141, 107) shows that such large rms slopes pertain to a sub-mm horizontal distance scale. The RTE model also reproduces the same BFM/AFM radiance difference, but as a direct consequence of multiple scattering between particles within the flat (zero topographic roughness) regolith layer. Approximately 80% of the radiance in the RTE model is contributed by photons scattered more than once. We conclude that topographic roughness of the regolith surface and multiple scattering between regolith particles can have a nearly identical effect on this BFM/AFM difference in the lunar radiance. Roughness and multiple scattering are strongly correlated parameters in the sense that any approximations regarding one of them will influence the value deduced for the other. A complete treatment of this work is published in Goguen et al 2010, Icarus 208, 548.

  5. APASS Landolt-Sloan BVgri photometry of Rave stars. I. Data, effective temperatures, and reddenings

    SciTech Connect

    Munari, U.; Siviero, A.; Henden, A.; Frigo, A.; Bienaymé, O.; Siebert, A.; Bland-Hawthorn, J.; Boeche, C.; Grebel, E. K.; Freeman, K. C.; Gibson, B. K.; Gilmore, G.; Kordopatis, G.; Helmi, A.; Levine, S. E.; Navarro, J. F.; Parker, Q. A.; Reid, W.; Seabroke, G. M.; and others

    2014-11-01

    We provide AAVSO Photometric All-Sky Survey (APASS) photometry in the Landolt BV and Sloan g'r'i' bands for all 425,743 stars included in the fourth RAVE Data Release. The internal accuracy of the APASS photometry of RAVE stars, expressed as the error of the mean of data obtained and separately calibrated over a median of four distinct observing epochs and distributed between 2009 and 2013, is 0.013, 0.012, 0.012, 0.014, and 0.021 mag for the B, V, g', r', and i' bands, respectively. The equally high external accuracy of APASS photometry has been verified on secondary Landolt and Sloan photometric standard stars not involved in the APASS calibration process and on a large body of literature data on field and cluster stars, confirming the absence of offsets and trends. Compared with the Carlsberg Meridian Catalog (CMC-15), APASS astrometry of RAVE stars is accurate to a median value of 0.098 arcsec. Brightness distribution functions for the RAVE stars have been derived in all bands. APASS photometry of RAVE stars, augmented by 2MASS JHK infrared data, has been χ{sup 2} fitted to a densely populated synthetic photometric library designed to widely explore temperature, surface gravity, metallicity, and reddening. Resulting T {sub eff} and E {sub B–V}, computed over a range of options, are provided and discussed, and will be kept updated in response to future APASS and RAVE data releases. In the process, we find that the reddening caused by a homogeneous slab of dust, extending for 140 pc on either side of the Galactic plane and responsible for E{sub B−V}{sup poles} = 0.036 ± 0.002 at the Galactic poles, is a suitable approximation of the actual reddening encountered at Galactic latitudes |b| ≥ 25°.

  6. APASS Landolt-Sloan BVgri Photometry of RAVE Stars. I. Data, Effective Temperatures, and Reddenings

    NASA Astrophysics Data System (ADS)

    Munari, U.; Henden, A.; Frigo, A.; Zwitter, T.; Bienaymé, O.; Bland-Hawthorn, J.; Boeche, C.; Freeman, K. C.; Gibson, B. K.; Gilmore, G.; Grebel, E. K.; Helmi, A.; Kordopatis, G.; Levine, S. E.; Navarro, J. F.; Parker, Q. A.; Reid, W.; Seabroke, G. M.; Siebert, A.; Siviero, A.; Smith, T. C.; Steinmetz, M.; Templeton, M.; Terrell, D.; Welch, D. L.; Williams, M.; Wyse, R. F. G.

    2014-11-01

    We provide AAVSO Photometric All-Sky Survey (APASS) photometry in the Landolt BV and Sloan g'r'i' bands for all 425,743 stars included in the fourth RAVE Data Release. The internal accuracy of the APASS photometry of RAVE stars, expressed as the error of the mean of data obtained and separately calibrated over a median of four distinct observing epochs and distributed between 2009 and 2013, is 0.013, 0.012, 0.012, 0.014, and 0.021 mag for the B, V, g', r', and i' bands, respectively. The equally high external accuracy of APASS photometry has been verified on secondary Landolt and Sloan photometric standard stars not involved in the APASS calibration process and on a large body of literature data on field and cluster stars, confirming the absence of offsets and trends. Compared with the Carlsberg Meridian Catalog (CMC-15), APASS astrometry of RAVE stars is accurate to a median value of 0.098 arcsec. Brightness distribution functions for the RAVE stars have been derived in all bands. APASS photometry of RAVE stars, augmented by 2MASS JHK infrared data, has been χ2 fitted to a densely populated synthetic photometric library designed to widely explore temperature, surface gravity, metallicity, and reddening. Resulting T eff and E B - V , computed over a range of options, are provided and discussed, and will be kept updated in response to future APASS and RAVE data releases. In the process, we find that the reddening caused by a homogeneous slab of dust, extending for 140 pc on either side of the Galactic plane and responsible for EpolesB-V = 0.036 ± 0.002 at the Galactic poles, is a suitable approximation of the actual reddening encountered at Galactic latitudes |b| >= 25°.

  7. ASPIN: Research project on near-Earth asteroid photometry in frame of the ISON optical network

    NASA Astrophysics Data System (ADS)

    Molotov, Igor; Inasaridze, Raguli; Elenin, Leonid; Krugly, Yurij; Rumyantsev, Vasilij; Namkhai, Tungalag; Schmalz, Sergei; Tsogt-Ochir, Shijirbayar

    International Scientific Optical Network (ISON) represents one of largest systems specializing in observation of space objects. The main goal of project is observations of space debris. As an additional task the regular photometry of near-Earth asteroids (NEAs) is carried out using the network’s telescopes with apertures from 0.4 m up to 2.6 m (ASPIN project - Asteroid Search and Photometry Initiative). The photometry is aimed at getting lightcurves of asteroids for solving different tasks concerning with physical properties of these celestial bodies. The lightcurves have been obtained with a typical photometric accuracy of 0.01-0.03 mag. The main purpose of the observations is to study characteristics of asteroids such as rotation period, size and shape of the body, surface composition and other. It is expected to detect an influence of the YORP effect. Special attention is paid to the detection of binary asteroids. During 2013 the photometric observations have been carried out at 12 observatories during more than 250 nights which have been allowed to obtain the data on 40 NEAs as well as 15 main-belt asteroids. In result the rotation periods have been determined for 8 NEAs in the first time and refined for 10 NEAs. Two binary systems were discovered. Lightcurves of 11 main-belt asteroids with diameters less than 10 km (binary systems or members of small clusters) were obtained. Several of the observed asteroids were radar targets - between them the NEA (367943) Duende (or 2012 DA14), which was approached to the Earth in day of falling the Chelyabinsk meteor on February 23, 2013. The obtained results will be presented and perspectives of NEA photometry with ISON telescopes will be discussed.

  8. The RSA survey of dwarf galaxies, 1: Optical photometry

    NASA Technical Reports Server (NTRS)

    Vader, J. Patricia; Chaboyer, Brian

    1994-01-01

    We present detailed surface photometry, based on broad B-band charge coupled device (CCD) images, of about 80 dwarf galaxies. Our sample represents approximately 10% of all dwarf galaxies identified in the vicinity of Revised Shapley-Ames (RSA) galaxies on high resolution blue photographic plates, referred to as the RSA survey of dwarf galaxies. We derive global properties and radial surface brightness profiles, and examine the morphologies. The radial surface brightness profiles of dwarf galaxies, whether early or late type, display the same varieties in shape and complexity as those of classical giant galaxies. Only a few are well described by a pure r(exp 1/4) law. Exponential profiles prevail. Features typical of giant disk galaxies, such as exponential profiles with a central depression, lenses, and even, in one case (IC 2041), a relatively prominent bulge are also found in dwarf galaxies. Our data suggest that the central region evolves from being bulge-like, with an r(exp 1/4) law profile, in bright galaxies to a lens-like structure in dwarf galaxies. We prove detailed surface photometry to be a helpful if not always sufficient tool in investigating the structure of dwarf galaxies. In many cases kinematic information is needed to complete the picture. We find the shapes of the surface brightness profiles to be loosely associated with morphological type. Our sample contains several new galaxies with properties intermediate between those of giant and dwarf ellipticals (but no M32-like objects). This shows that such intermediate galaxies exist so that at least a fraction of early-type dwarf ellipticals is structurally related to early-type giants instead of belonging to a totally unrelated, disjunct family. This supports an origin of early-type dwarf galaxies as originally more massive systems that acquired their current morphology as a result of substantial, presumable supernova-driven, mass loss. On the other hand, several early-type dwarfs in our sample are merger candidates. Merger events may lead to anisotropic velocity distributions in systems of any luminosity, including dwarfs. The RSA sample of dwarf galaxies is more likely to contain mergers because, in contrast to earlier dwarf galaxy surveys that have focused on clusters and rich groups of galaxies, the RSA dwarfs are typically located in low density environments. The occurrence of mergers among dwarf galaxies is of interest in connection with the rapid evolution of faint blue galaxy counts at redshift z less than 1 which suggests that dwarf galaxies were about five times more numerous in the recent past. Finally, our sample contains several examples of late-type dwarfs and 'transition' types that are potential precursors of nucleated early-type dwarfs. All the above processes--mass loss, mergers, astration--are likely to have contributed to the formation of the current population of diffuse early-type dwarfs. A few new redshifts of dwarf galaxies are reported in this paper.

  9. The RSA survey of dwarf galaxies, 1: Optical photometry

    NASA Astrophysics Data System (ADS)

    Vader, J. Patricia; Chaboyer, Brian

    1994-10-01

    We present detailed surface photometry, based on broad B-band charge coupled device (CCD) images, of about 80 dwarf galaxies. Our sample represents approximately 10% of all dwarf galaxies identified in the vicinity of Revised Shapley-Ames (RSA) galaxies on high resolution blue photographic plates, referred to as the RSA survey of dwarf galaxies. We derive global properties and radial surface brightness profiles, and examine the morphologies. The radial surface brightness profiles of dwarf galaxies, whether early or late type, display the same varieties in shape and complexity as those of classical giant galaxies. Only a few are well described by a pure r1/4 law. Exponential profiles prevail. Features typical of giant disk galaxies, such as exponential profiles with a central depression, lenses, and even, in one case (IC 2041), a relatively prominent bulge are also found in dwarf galaxies. Our data suggest that the central region evolves from being bulge-like, with an r1/4 law profile, in bright galaxies to a lens-like structure in dwarf galaxies. We prove detailed surface photometry to be a helpful if not always sufficient tool in investigating the structure of dwarf galaxies. In many cases kinematic information is needed to complete the picture. We find the shapes of the surface brightness profiles to be loosely associated with morphological type. Our sample contains several new galaxies with properties intermediate between those of giant and dwarf ellipticals (but no M32-like objects). This shows that such intermediate galaxies exist so that at least a fraction of early-type dwarf ellipticals is structurally related to early-type giants instead of belonging to a totally unrelated, disjunct family. This supports an origin of early-type dwarf galaxies as originally more massive systems that acquired their current morphology as a result of substantial, presumable supernova-driven, mass loss. On the other hand, several early-type dwarfs in our sample are merger candidates. Merger events may lead to anisotropic velocity distributions in systems of any luminosity, including dwarfs. The RSA sample of dwarf galaxies is more likely to contain mergers because, in contrast to earlier dwarf galaxy surveys that have focused on clusters and rich groups of galaxies, the RSA dwarfs are typically located in low density environments. The occurrence of mergers among dwarf galaxies is of interest in connection with the rapid evolution of faint blue galaxy counts at redshift z less than 1 which suggests that dwarf galaxies were about five times more numerous in the recent past.

  10. Spatio-temporal patterns in land use and management affecting surface runoff response of agricultural catchments—A review

    NASA Astrophysics Data System (ADS)

    Fiener, P.; Auerswald, K.; Van Oost, K.

    2011-05-01

    Surface runoff and associated erosion processes adversely affect soil and surface water quality. There is increasing evidence that a sound understanding of spatial-temporal dynamics of land use and management are crucial to understanding surface runoff processes and underpinning mitigation strategies. In this review, we synthesise the effects of (1) temporal patterns of land management of individual fields, and (2) spatio-temporal interaction of several fields within catchments by applying semivariance analysis, which allows the extent and range of the different patterns to be compared. Consistent effects of management on the temporal dynamics of surface runoff of individual fields can be identified, some of which have been incorporated into small-scale hydrological models. In contrast, the effects of patchiness, the spatial organisation of patches with different soil hydrological properties, and the effects of linear landscape structures are less well understood and are rarely incorporated in models. The main challenge for quantifying these effects arises from temporal changes within individual patches, where the largest contrasts usually occur in mid-summer and cause a seasonally varying effect of patchiness on the overall catchment response. Some studies indicate that increasing agricultural patchiness, due to decreasing field sizes, reduces the catchment-scale response to rainfall, especially in cases of Hortonian runoff. Linear structures associated with patchiness of fields (e.g. field borders, ditches, and ephemeral gullies) may either increase or decrease the hydraulic connectivity within a catchment. The largest gap in research relates to the effects and temporal variation of patch interaction, the influence of the spatial organisation of patches and the interaction with linear structures. In view of the substantial changes in the structure of agricultural landscapes occurring throughout the world, it is necessary to improve our knowledge of the influence of patchiness and connectivity, and to implement this knowledge in new modelling tools.

  11. HST BVI photometry of Triton and Proteus

    NASA Astrophysics Data System (ADS)

    Pascu, Dan; Storrs, Alex D.; Wells, Eddie N.; Hershey, John L.; Rohde, James R.; Seidelmann, P. Kenneth; Currie, Douglas G.

    2006-12-01

    BVI photometry of Triton and Proteus was derived from HST images taken in 1997. The VEGAMAG photometric technique was used. Triton was found to be brighter by a few percent than observations of the 1970's and 1980's, as expected due to the increasingly greater exposure of the bright south polar region. The leading side was also found to be brighter than the trailing side by 0.09 mag in all filters—50% larger than reported by Franz [Franz, O.G., 1981. Icarus 45, 602-606]. Contrary to our previous results [Pascu, D., et al., 1998. Bull. Am. Astron. Soc. 30, 1101], we found no episodic reddening. Our previous conclusions were based on an inaccurate early version of the Charge Transfer Efficiency (CTE) correction. The present result limits the start of the reddening event reported by Hicks and Buratti [Hicks, M.D., Buratti, B.J., 2004. Icarus 171, 210-218]. Our ( B- V) result of 0.70±0.01 supports the global blueing described by Buratti et al. [Buratti, B.J., Goguen, J.D., Gibson, J., Mosher, J., 1994. Icarus 110, 303-314]. Our observations of July 1997 agree with the Voyager results and are among the bluest colors seen. We found Proteus somewhat brighter than earlier studies, but in good agreement with the recent value given by Karkoschka [Karkoschka, E., 2003. Icarus 162, 400-407]. A leading/trailing brightness asymmetry was detected for Proteus, with the leading side 0.1 mag brighter. The unique differences in action of the endogenic and exogenic processes on Triton and Proteus provides an opportunity to separate the endogenic and exogenic effects on Triton.

  12. Narrowband photometry of Comet Austin 1990V

    NASA Astrophysics Data System (ADS)

    Waniak, W.; Magdziarz, P.; Winiarski, M.

    1994-03-01

    The results of photoelectric photometry with the narrowband CN, C3, C2, blue continuum, and ultraviolet continuum International Halley Watch (IHW) interference filters are present. The observations were carried out with a set of diaphragms of different radii. Vectorial Monte Carlo modeling of the cometary coma was used for the determination of production rates of the radicals, the parent and daughter lifetimes, and the daughter ejection velocities from the parents. The CN and C2 parent lifetimes (at 1.0 AU) were 2.7 +/- 1.3 x 104 and 2.3 +/- 0.6 x 104 sec, respectively, and the lifetimes of CN, C3 and C2, molecules were 2.1 +/- 3.0 x 105, 1.8 +/- 2.0 x 105, and 1.1 +/- 0.4 x 105 sec (at 1.0 AU), respectively. The daughter ejection velocities from parents were 2.6 +/- 1.2 km/sec for the CN and 0.1 +/- 0.8 km/sec for the C2 molecule. The dependence on heliocentric distance of the molecules and dust production rates in the range of 0.7/1.0 AU was described by the power law function rh-n. The power index was 2.97 +/- 0.11 for CN, 2.34 +/- 0.55 for C3, 2.44 +/- 0.17 for C2, and 3.44 +/- 0.51 for dust. Relative abundances of CN and C3 for Comet Austin at 1.0 AU postperihelion were similar to the 'normal' ones with some enrichment of the C2 molecule.

  13. Dithering Strategies and Point-Source Photometry

    SciTech Connect

    Samsing, Johan; Kim, Alex G

    2011-02-22

    The accuracy in the photometry of a point source depends on the point-spread function (PSF), detector pixelization, and observing strategy. The PSF and pixel response describe the spatial blurring of the source, the pixel scale describes the spatial sampling of a single exposure, and the observing strategy determines the set of dithered exposures with pointing offsets from which the source flux is inferred. In a wide-field imaging survey, sources of interest are randomly distributed within the field of view and hence are centered randomly within a pixel. A given hardware configuration and observing strategy therefore have a distribution of photometric uncertainty for sources of fixed flux that fall in the field. In this article we explore the ensemble behavior of photometric and position accuracies for different PSFs, pixel scales, and dithering patterns. We find that the average uncertainty in the flux determination depends slightly on dither strategy, whereas the position determination can be strongly dependent on the dithering. For cases with pixels much larger than the PSF, the uncertainty distributions can be non-Gaussian, with rms values that are particularly sensitive to the dither strategy. We also find that for these configurations with large pixels, pointings dithered by a fractional pixel amount do not always give minimal average uncertainties; this is in contrast to image reconstruction for which fractional dithers are optimal. When fractional pixel dithering is favored, a pointing accuracy of better than {approx}0.15 {approx}0.15 pixel width is required to maintain half the advantage over random dithers.

  14. Naturally Occurring Deletional Mutation in the C-Terminal Cytoplasmic Tail of CCR5 Affects Surface Trafficking of CCR5

    PubMed Central

    Shioda, Tatsuo; Nakayama, Emi E.; Tanaka, Yuetsu; Xin, Xiaomi; Liu, Huanliang; Kawana-Tachikawa, Ai; Kato, Atsushi; Sakai, Yuko; Nagai, Yoshiyuki; Iwamoto, Aikichi

    2001-01-01

    CCR5 is an essential coreceptor for the cellular entry of R5 strains of human immunodeficiency virus type 1 (HIV-1). CCR5-893(−) is a single-nucleotide deletion mutation which is observed exclusively in Asians (M. A. Ansari-Lari, et al., Nat. Genet. 16:221–222, 1997). This mutant gene produces a CCR5 which lacks the entire C-terminal cytoplasmic tail. To assess the effect of CCR5-893(−) on HIV-1 infection, we generated a recombinant Sendai virus expressing the mutant CCR5 and compared its HIV-1 coreceptor activity with that of wild-type CCR5. Although the mutant CCR5 has intact extracellular domains, its coreceptor activity was much less than that of wild-type CCR5. Flow cytometric analyses and confocal microscopic observation of cells expressing the mutant CCR5 revealed that surface CCR5 levels were greatly reduced in these cells, while cytoplasmic CCR5 levels of the mutant CCR5 were comparable to that of the wild type. Peripheral blood CD4+ T cells obtained from individuals heterozygous for this allele expressed very low levels of CCR5. These data suggest that the CCR5-893(−) mutation affects intracellular transport of CCR5 and raise the possibility that this mutation also affects HIV-1 transmission and disease progression. PMID:11238872

  15. The highly unusual outgassing of Comet 103P/Hartley 2 from narrowband photometry and imaging of the coma

    NASA Astrophysics Data System (ADS)

    Knight, Matthew M.; Schleicher, David G.

    2013-02-01

    We report on photometry and imaging of Comet 103P/Hartley 2 obtained at Lowell Observatory from 1991 through 2011. We acquired photoelectric photometry on two nights in 1991, four nights in 1997/1998, and 13 nights in 2010/2011. We observed a strong secular decrease in water and all other observed species production in 2010/2011 from the 1991 and 1997/1998 levels. We see evidence for a strong asymmetry with respect to perihelion in the production rates of our usual bandpasses, with peak production occurring ˜10 days post-perihelion and production rates considerably higher post-perihelion. The composition was "typical," in agreement with the findings of other investigators. We obtained imaging on 39 nights from 2010 July until 2011 January. We find that, after accounting for their varying parentage and lifetimes, the C2 and C3 coma morphology resemble the CN morphology we reported previously. These species exhibited an hourglass shape in October and November, and the morphology changed with rotation and evolved over time. The OH and NH coma morphology showed hints of an hourglass shape near the nucleus, but was also enhanced in the anti-sunward hemisphere. This tailward brightness enhancement did not vary significantly with rotation and evolved with the viewing geometry. We conclude that all five gas species likely originate from the same source regions on the nucleus, but that OH and NH were derived from small grains of water and ammonia ice that survived long enough to be affected by radiation pressure and driven in the anti-sunward direction. We detected the faint, sunward facing dust jet reported by other authors, and did not detect a corresponding gas feature. This jet varied little during a night but exhibited some variations from night to night, suggesting it is located near the total angular momentum vector. Overall, our imaging results support the conclusions of other authors that Hartley 2's "hyperactivity" is caused by icy particles of various sizes that are lifted off the surface and break up in the coma to greatly increase the effective active surface area.

  16. Correlating Total Visual Magnitude Estimates and CCD Photometry for Comets

    NASA Astrophysics Data System (ADS)

    Kidger, Mark Richard

    2015-08-01

    A key facet of understanding the activity of comets is coverage of their light curve. For some comets such as 2P/Encke there is good light curve coverage from visual observers extending back over many returns over more than 2 centuries. However, in recent years, CCD photometry by amateur astronomers has become the dominant data source and the number of total visual magnitude estimates has reduced sharply, making comparison of recent and historical photometric data for comets increasingly difficult. The relationship between total visual magnitude estimates - dominated by the emission from the Swan bands of C2 - and CCD aperture photometry - dominated by the dust continuum - has been far from clear.This paper compares CCD aperture photometry and total visual magnitude for several recent well-observed bright comets, including C/2014 Q2 (Lovejoy), C/2012 S1 (ISON) and C/2011 L4 (PanSTARRS) using a consistent and homogeneous database of observations from (mainly) Spanish observers. For comets with a 1/r radial coma profile, good agreement is found between CCD aperture photometry and total visual magnitude estimates for a CCD aperture corresponding to a physical coma diameter of ≈105km.The relationship between the coma radial brightness slope and the equivalent physical aperture for CCD photometry to obtain agreement with total visual magnitude estimates is investigated.

  17. HST photometry of the trapezium cluster

    NASA Technical Reports Server (NTRS)

    Prosser, Charles F.; Stauffer, John R.; Hartmann, Lee; Soderblom, David R.; Jones, Burton F.; Werner, Michael W.; Mccaughrean, Mark J.

    1994-01-01

    We have obtained images of 11 fields in the Trapezium cluster with the Planetary Camera (PC) of the Hubble Space Telescope (HST) in order to extend Herbig & Terndrup's (1986) study of this prototype, dense embedded cluster to fainter magnitudes than is possible from the ground. Using these images, we have identified 319 stars within an area of approximately 12 sq arc min corresponding roughly to a volume of approximately 0.065 cu pc assuming the cluster is approximately spherically symmetric. Our completeness limits for star identification in V-band and I-band images are V approximately = 20 and I(sub c) approximately = 19 respectively, corresponding to a mass limit of approximately 0.15 solar mass if the faintest stars have the same average A(sub v) as that estimated for the brighter stars in the cluster. We have compared the V versus V-I color-magnitude diagram derived from the HST photometry to new theoretical isochrones. Star formation in the Trapezium appears to be remarkably coeval, with greater than or = 80% of the stars having inferred ages less than 1 Myr. Over the somewhat limited mass range of the observations, there is no evidence for 'bimodal' star formation-the high- and low-mass stars appear to have the same ages. The sharp cores of the HST images and the small angular size of the PC pixels has allowed us to identify 35 new visual binaries in the cluster with separations from approximately 0.06 arc sec (approximately 26 AU) to approximately 1.0 arc sec (approximately 440 AU). For the range of binary separations that we are sensitive to, the observed binary frequency for the Trapezium is essentially identical to that estimated for field low-mass stars by Duquennoy & Mayor (1991). The most straightfoward inference from this result is that binaries in this separation are unlikely to be formed by a tidal capture process. We have also identified three stars which have associated compact nebulosity visible in the HST images. One of these star + nebulosity cases was previously identified by O'Dell, Wen, & Hu (1993)-these objects appear to form a class of objects whose circumstellar matter is being 'lit up', most likely by Theta(sup 1) Ori C, enabling the gas to be observable at both optical and radio wavelengths (Felli et al. 1993a, b). We provide a brief summary of the optical properties of the other radio sources which appear in our PC images.

  18. Processes affecting the transport of Cryptosporidium parvum and other persistent pathogens in surface- and ground-waters

    NASA Astrophysics Data System (ADS)

    Packman, A. I.; Lau, B. L.; Harter, T.; Atwill, E. R.

    2007-12-01

    Waterborne diseases are transmitted through numerous environmental pathways, and their migration is strongly mediated by interaction with a wide variety of sediments and other natural materials during transport. Here we provide an overview of factors that affect the fate of persistent water-borne pathogens, focusing particularly on the zoonotic pathogen Cryptosporidium parvum as an example. While individual microbial cells are both small and have low specific gravity, suggesting that they should be highly mobile and remain suspended for long periods of time, attachment to a variety of background materials can substantially reduce pathogen mobility. Cryptosporidium oocysts readily associate with both inorganic and organic particles, resulting in the formation of aggregates. This process tends to increase the effective settling velocity of C. parvum in surface waters. Similarly, pathogens readily become associated with the solid matrix during transport in groundwater, resulting in removal by filtration. However, this process is reversible with C. parvum, resulting in a slow long-term release following the initial deposition. Pathogens also become associated with biofilms, which are surface-attached communities of microorganisms in a gelatinous matrix. The presence of biofilms increases the immobilization and retention of Cryptosporidium on solid surfaces. All of these processes influence pathogen transmission in surface waters such as rivers and water-supply canals. In these environments, pathogens can be immobilized by deposition into stable sediment beds by a combination of gravitational sedimentation and advection into pore waters followed by subsurface filtration. Association with background suspended matter tends to increase pathogen deposition by sedimentation, and the presence of benthic (sedimentary) biofilms also tends to increase pathogen retention. For pathogens that remain viable for long periods of time in natural aquatic systems, as is the case with Cryptosporidium and other cyst-and spore-forming organisms, then the sediments and sedimentary biofilms become an environmental reservoir of pathogens. Cysts retained in biofilms appear to be relatively difficult to resuspend, but slow, long-term biological release and high-flow events that mobilize streambed sediments both deliver pathogens into transport.

  19. Uranium in Surface Waters and Sediments Affected by Historical Mining in the Denver West 1:100,000 Quadrangle, Colorado

    USGS Publications Warehouse

    Zielinski, Robert A.; Otton, James K.; Schumann, R. Randall; Wirt, Laurie

    2008-01-01

    Geochemical sampling of 82 stream waters and 87 stream sediments within mountainous areas immediately west of Denver, Colorado, was conducted by the U.S. Geological Survey in October 1994. The primary purpose was to evaluate regionally the effects of geology and past mining on the concentration and distribution of uranium. The study area contains uranium- and thorium-rich bedrock, numerous noneconomic occurrences of uranium minerals, and several uranium deposits of variable size and production history. During the sampling period, local streams had low discharge and were more susceptible to uranium-bearing acid drainage originating from historical mines of base- and precious-metal sulfides. Results indicated that the spatial distribution of Precambrian granites and metamorphic rocks strongly influences the concentration of uranium in stream sediments. Within-stream transport increases the dispersion of uranium- and thorium rich mineral grains derived primarily from granitic source rocks. Dissolved uranium occurs predominantly as uranyl carbonate complexes, and concentrations ranged from less than 1 to 65 micrograms per liter. Most values were less than 5 micrograms per liter, which is less than the current drinking water standard of 30 micrograms per liter and much less than locally applied aquatic-life toxicity standards of several hundred micrograms per liter. In local streams that are affected by uranium-bearing acid mine drainage, dissolved uranium is moderated by dilution and sorptive uptake by stream sediments. Sorbents include mineral alteration products and chemical precipitates of iron- and aluminum-oxyhydroxides, which form where acid drainage enters streams and is neutralized. Suspended uranium is relatively abundant in some stream segments affected by nearby acid drainage, which likely represents mobilization of these chemical precipitates. The 234U/238U activity ratio of acid drainage (0.95-1.0) is distinct from that of local surface waters (more than 1.05), and this distinctive isotopic composition may be preserved in iron-oxyhydroxide precipitates of acid drainage origin. The study area includes a particularly large vein-type uranium deposit (Schwartzwalder mine) with past uranium production. Stream water and sediment collected downstream from the mine's surface operations have locally anomalous concentrations of uranium. Fine-grained sediments downstream from the mine contain rare minute particles (10-20 micrometers) of uraninite, which is unstable in a stream environment and thus probably of recent origin related to mining. Additional rare particles of very fine grained (less than 5 micrometer) barite likely entered the stream as discharge from settling ponds in which barite precipitation was formerly used to scavenge dissolved radium from mine effluent.

  20. CCD Photometry of Bright Stars Using Objective Wire Mesh

    NASA Astrophysics Data System (ADS)

    Kamiński, Krzysztof; Schwarzenberg-Czerny, Aleksander; Zgórz, Marika

    2014-06-01

    Obtaining accurate photometry of bright stars from the ground remains problematic due to the danger of overexposing the target and/or the lack of suitable nearby comparison stars. The century-old method of using objective wire mesh to produce multiple stellar images seems promising for the precise CCD photometry of such stars. Furthermore, our tests on β Cep and its comparison star, differing by 5 mag, are very encouraging. Using a CCD camera and a 20 cm telescope with the objective covered by a plastic wire mesh, in poor weather conditions, we obtained differential photometry with a precision of 4.5 mmag per two minute exposure. Our technique is flexible and may be tuned to cover a range as big as 6-8 mag. We discuss the possibility of installing a wire mesh directly in the filter wheel.

  1. CCD Photometry of bright stars using objective wire mesh

    SciTech Connect

    Kami?ski, Krzysztof; Zgrz, Marika; Schwarzenberg-Czerny, Aleksander

    2014-06-01

    Obtaining accurate photometry of bright stars from the ground remains problematic due to the danger of overexposing the target and/or the lack of suitable nearby comparison stars. The century-old method of using objective wire mesh to produce multiple stellar images seems promising for the precise CCD photometry of such stars. Furthermore, our tests on ? Cep and its comparison star, differing by 5 mag, are very encouraging. Using a CCD camera and a 20 cm telescope with the objective covered by a plastic wire mesh, in poor weather conditions, we obtained differential photometry with a precision of 4.5 mmag per two minute exposure. Our technique is flexible and may be tuned to cover a range as big as 6-8 mag. We discuss the possibility of installing a wire mesh directly in the filter wheel.

  2. Near-IR Photometry of Nova Del 2013

    NASA Astrophysics Data System (ADS)

    Cass, C. A.; Carlon, L. R.; Corgan, T. D.; Dykhoff, A. D.; Gehrz, D. R.; Shenoy, P. D.

    2013-08-01

    Subjects: Infra-Red, Nova We report Near-IR photometry of Nova Del 2013 taken with the 0.76-m infrared telescope at the University of Minnesota's O'Brien Observatory (Marine on St. Croix, Minnesota, USA). RIJHKLM photometry were obtained on August 21.17 and 23.13 UT using an AsSi bolometer. Vega (alpha Lyrae) was used as the standard star. Our photometry show: August 21.17 UT: R = 5.1 +/- 0.1, I = 4.6 +/- 0.1, J = 4.6 +/- 0.1, H = 4.1 +/- 0.1, K = 3.9 +/- 0.1, L = 2.7 +/- 0.2, M = +2.2 +/- 0.2.

  3. Photometry Of The Semi-regular Variable Tx Tau

    NASA Astrophysics Data System (ADS)

    Wyman, Katherine; Spear, G.; McLin, K.; Cominsky, L.; Mankiewicz, L.; Reichart, D.; Ivarsen, K.

    2009-12-01

    We report V-band and I-band photometry for the SRA type variable TX Tau. Photometry was obtained using the robotic telescope GORT at the Hume Observatory (NASA funded through Sonoma State University) and the PROMPT robotic telescopes at Cerro Tololo Inter-American Observatory (NSF and NASA funded through the University of North Carolina). Photometry was also obtained using the PI of the Sky optical transient search system at Las Campanas Observatory developed by a consortium of institutions in Poland. Modern periods are determined, the V-band and I-band light curves are compared, and V-I colors are derived. It is possible that the classification for this variable should be reconsidered.

  4. How Does the Gibbs Inequality Condition Affect the Stability and Detachment of Floating Spheres from the Free Surface of Water?

    PubMed

    Feng, Dong-Xia; Nguyen, Anh V

    2016-03-01

    Floating objects on the air-water interfaces are central to a number of everyday activities, from walking on water by insects to flotation separation of valuable minerals using air bubbles. The available theories show that a fine sphere can float if the force of surface tension and buoyancies can support the sphere at the interface with an apical angle subtended by the circle of contact being larger than the contact angle. Here we show that the pinning of the contact line at the sharp edge, known as the Gibbs inequality condition, also plays a significant role in controlling the stability and detachment of floating spheres. Specifically, we truncated the spheres with different angles and used a force sensor device to measure the force of pushing the truncated spheres from the interface into water. We also developed a theoretical modeling to calculate the pushing force that in combination with experimental results shows different effects of the Gibbs inequality condition on the stability and detachment of the spheres from the water surface. For small angles of truncation, the Gibbs inequality condition does not affect the sphere detachment, and hence the classical theories on the floatability of spheres are valid. For large truncated angles, the Gibbs inequality condition determines the tenacity of the particle-meniscus contact and the stability and detachment of floating spheres. In this case, the classical theories on the floatability of spheres are no longer valid. A critical truncated angle for the transition from the classical to the Gibbs inequality regimes of detachment was also established. The outcomes of this research advance our understanding of the behavior of floating objects, in particular, the flotation separation of valuable minerals, which often contain various sharp edges of their crystal faces. PMID:26837262

  5. International Studies of Hazardous Groundwater/Surface Water Exchange in the Volcanic Eruption and Tsunami Affected Areas of Kamchatka

    NASA Astrophysics Data System (ADS)

    Kontar, Y. A.; Gusiakov, V. K.; Izbekov, P. E.; Gordeev, E.; Titov, V. V.; Verstraeten, I. M.; Pinegina, T. K.; Tsadikovsky, E. I.; Heilweil, V. M.; Gingerich, S. B.

    2012-12-01

    During the US-Russia Geohazards Workshop held July 17-19, 2012 in Moscow, Russia the international research effort was asked to identify cooperative actions for disaster risk reduction, focusing on extreme geophysical events. As a part of this recommendation the PIRE project was developed to understand, quantify, forecast and protect the coastal zone aquifers and inland water resources of Kamchatka (Russia) and its ecosystems affected by the November 4, 1952 Kamchatka tsunami (Khalatyrka Beach near Petropavlovsk-Kamchatskiy) and the January 2, 1996 Karymskiy volcano eruption and the lake tsunami. This project brings together teams from U.S. universities and research institutions located in Russia. The research consortium was briefed on recent technical developments and will utilize samples secured via major international volcanic and tsunami programs for the purpose of advancing the study of submarine groundwater discharge (SGD) in the volcanic eruption and tsunami affected coastal areas and inland lakes of Kamchatka. We plan to accomplish this project by developing and applying the next generation of field sampling, remote sensing, laboratory techniques and mathematical tools to study groundwater-surface water interaction processes and SGD. We will develop a field and modeling approach to define SGD environment, key controls, and influence of volcano eruption and tsunami, which will provide a framework for making recommendations to combat contamination. This is valuable for politicians, water resource managers and decision-makers and for the volcano eruption and tsunami affected region water supply and water quality of Kamchatka. Data mining and results of our field work will be compiled for spatial modeling by Geo-Information System (GIS) using 3-D Earth Systems Visualization Lab. The field and model results will be communicated to interested stakeholders via an interactive web site. This will allow computation of SGD spatial patterns. In addition, thanks to the conceptual integrated approach, the mathematical tool will be transportable to other regions affected by volcanic eruption and tsunami. We will involve students in the work, incorporate the results into our teaching portfolio and work closely with the IUGG GeoRisk Commission and AGU Natural Hazards Focus Group to communicate our findings to the broader public, specifically local communities that will be most impacted. Under the PIRE education component, a cohort of U.S. and Russian post-doctoral researchers and students will receive training and contribute to the overall natural hazards SGD science agenda in cooperation with senior U.S. researchers and leading investigators from the Russian institutions. Overall, the extensive team of researchers, students and institutions is poised to deliver an innovative and broad spectrum of science associated with the study of SGD in the volcanic eruption and tsunami affected areas, in a way not possible to achieve in isolation.

  6. Inverse problems of NEO photometry: Imaging the NEO population

    NASA Astrophysics Data System (ADS)

    Kaasalainen1, Mikko; Durech, Josef

    2007-05-01

    Photometry is the main source of information on NEOs (and other asteroids) en masse. Surveys such as Pan-STARRS and LSST will produce colossal photometric databases that can readily be used for mapping the physical characteristics of the whole asteroid population. These datasets are efficiently enriched by any additional dense photometric or other observations. Due to their quickly changing geometries with respect to the Earth, NEOs are the subpopulation that can be mapped the fastest. I review the state of the art in the construction of physical asteroid models from sparse and/or dense photometric data (that can also be combined with other data modes). The models describe the shapes, spin states, scattering properties and surface structure of the targets, and are the solutions of inverse problems necessarily involving comprehensive mathematical analysis. I sum up what we can and cannot get from photometric data, and how all this is done in practice. I also discuss the new freely available software package for solving photometric inverse problems (soon to be released). The analysis of photometric datasets will very soon become an automated industry, resulting in tens of thousands of asteroid models, a large portion of them NEOs. The computational effort in this is considerable in both computer and human time, which means that a large portion of the targets is likely to be analyzed only once. This, again, means that we have to have a good understanding of the reliability of our models, and this is impossible without a thorough understanding of the mathematical nature of the inverse problem(s) involved. Very important concepts are the uniqueness and stability of the solution, the parameter spaces, the so-called inverse crimes in simulations and error prediction, and the domination of systematic errors over random ones.

  7. BATC 15 Band Photometry of the Open Cluster NGC 188

    NASA Astrophysics Data System (ADS)

    Wang, Jiaxin; Ma, Jun; Wu, Zhenyu; Wang, Song; Zhou, Xu

    2015-08-01

    This paper presents CCD multicolor photometry for the old open cluster NGC 188. The observations were carried out as part of the Beijing-Arizona-Taiwan-Connecticut Multicolor Sky Survey from 1995 February to 2008 March, using 15 intermediate-band filters covering 3000-10000 Å. By fitting the Padova theoretical isochrones to our data, the fundamental parameters of this cluster are derived: an age of t=7.5+/- 0.5 Gyr, a distance modulus of {(m-M)}0=11.17+/- 0.08, and a reddening of E(B-V)=0.036+/- 0.010. The radial surface density profile of NGC 188 is obtained using the star count. By fitting the King model, the structural parameters of NGC 188 are derived: a core radius of {R}c=3\\buildrel{ \\prime}\\over{.} 80, a tidal radius of {R}t=44\\buildrel{ \\prime}\\over{.} 78, and a concentration parameter of {C}0={log}({R}t/{R}c)=1.07. Fitting the mass function (MF) to a power-law function φ (m)\\propto {m}α , the slopes of the MFs for different spatial regions are derived. We find that NGC 188 presents a slope break in the MF. The break mass is {m}{break}=0.885 {M}⊙ . In the mass range above {m}{break}, the slope of the overall region is α =-0.76. The slope of the core region is α =1.09, and the slopes of the external regions are α =-0.86 and α =-2.15, respectively. In the mass range below {m}{break}, these slopes are α =0.12, α =4.91, α =1.33, and α =-1.09, respectively. The mass segregation in NGC 188 is reflected in the obvious variation of the slopes in different spatial regions of this cluster.

  8. The Founders of the XXth Century Stellar Photometry in Russia

    NASA Astrophysics Data System (ADS)

    Pustylnik, I.; Mironov, A.

    Our contribution is dedicated to two ``godfathers'' of astrophotometry in Russia - Vitold Karlovich Ceraski (1849-1925) and Vladimir Borisovich Nikonov (1905-1987). We discuss their scientific legacy and its impact upon the formation of the school of stellar photometry in Russia and the USSR. The graduate of Moscow University in 1871 V. Ceraski started his scientific career in the University astronomical observatory. Already at the dawn of XXth century he was universally regarded as an indisputable authority in Russian astrophotometry. Ceraski introduced essential improvements into the K.-F. Zöllner's visual polarimetric photometer. With its aid he measured in 1903-1905 the stellar magnitude of the Sun with an accuracy close to its modern value (within a 5 % margin) by carefully comparing the brightness of Venus with that of the speck of the solar light reflected from the convex glass surface (during the day) and by comparing the brightness of Venus with that of the brightest stars (in the night). V. Nikonov, the graduate of Leningrad University, in 1925 embarked upon scientific investigations in the local Astronomical Institute. During these years the 13 inch reflector has been installed by Leningrad astronomers at the mountain Kanobili (Abastumani observatory, Georgia). In 1937 Nikonov constructed the first in the USSR photoelectric photometer. Experiments with it indicated that the attainable precision for 4.5m stars amounted to 0.003m. It was obvious for Nikonov that with such a precision one should exercise extreme care in reduction of stellar magnitudes beyond the earth's upper atmosphere. In 1944 he elaborated a method to account for atmospheric extinction which is now universally known as Nikonov's method. Its underlying idea lies in the observations of all non-variable stars available in the program for different air masses.

  9. The spotted contact binary SS ARIETIS - Spectroscopy and infrared photometry

    NASA Astrophysics Data System (ADS)

    Rainger, P. P.; Bell, S. A.; Hilditch, R. W.

    1992-02-01

    The first infrared photometry for the W-UMa system SS Ari is presented. An analysis based on medium-resolution spectroscopy presented here shows that SS Ari is a W-type system with a mass ratio of 0.33. It seems certain that the asymmetry in the published light curves and those obtained for this study can be explained by the effect of spots on one or possibly both components of the system. The precise location, size and temperature of these spots require the use of Doppler Imaging techniques in conjunction with high-quality multiband photometry.

  10. HUBBLE SPACE TELESCOPE Photometry of the Globular Cluster M4

    NASA Astrophysics Data System (ADS)

    Ibata, Rodrigo A.; Richer, Harvey B.; Fahlman, Gregory G.; Bolte, Michael; Bond, Howard E.; Hesser, James E.; Pryor, Carlton; Stetson, Peter B.

    1999-02-01

    This paper presents a detailed description of the acquisition and processing of a large body of imaging data for three fields in the globular cluster M4 taken with the Wide Field and Planetary Camera 2 aboard the Hubble Space Telescope. Analysis with the ALLFRAME package yielded the deepest photometry yet obtained for this cluster. The resulting data set for 4708 stars (positions and calibrated photometry in V, I, and, in two fields, U) spanning approximately six cluster core radii is presented. The scientific analysis is deferred to three companion papers, which investigate the significant white dwarf population discovered and the main-sequence population.

  11. A Study of Dust Cloud Parameters by Vilnius Photometry

    NASA Astrophysics Data System (ADS)

    Smriglio, F.; Dasgupta, A. K.; Boyle, R. P.

    Three-dimensional classification of stars based on their seven-color CCD photometry in the Vilnius system has been succesfully applied to study the small scale structure of interstellar dust clouds. In the present paper the statistical equations of Munch are modified and applied to stars located beyond the galactic absorbing layer. This particular use of Munch's statistics and the properties of CCD photometry in the Vilnius system offer a better possibility of probing the small scale structure of interstellar medium outside of the solar vicinity. This new technique and the first results are discussed.

  12. Does the temperature of beverages affect the surface roughness, hardness, and color stability of a composite resin?

    PubMed Central

    Tuncer, Duygu; Karaman, Emel; Firat, Esra

    2013-01-01

    Objective: To investigate the effect of beverages’ temperature on the surface roughness, hardness, and color stability of a composite resin. Materials and Methods: Fifty specimens of the Filtek Z250 composite (3M ESPE, Dental Products, St.Paul, MN, USA) were prepared and initial roughness, microhardness, and color were measured. Then the specimens were randomly divided into five groups of 10 specimens each: Coffee at 70°C, coffee at 37°C, cola at 10°C, cola at 37°C, and artificial saliva (control). After the samples were subjected to 15 min × 3 cycles per day of exposure to the solutions for 30 days, the final measurements were recorded. Results: After immersion in beverages, the artificial saliva group showed hardness values higher than those of the other groups (P < 0.001) and the microhardness values were significantly different from the initial values in all groups except for the control group. Both cola groups showed roughness values higher than the baseline values (P < 0.05), while the other groups showed values similar to the baseline measurements. When ΔE measurements were examined, the 70°C coffee group showed the highest color change among all the groups (P < 0.05). Conclusion: High-temperature solutions caused alterations in certain properties of composites, such as increased color change, although they did not affect the hardness or roughness of the composite resin material tested. PMID:24883021

  13. Infrared space observatory photometry of circumstellar dust in Vega-type systems

    NASA Technical Reports Server (NTRS)

    Fajardo-Acosta, S. B.; Stencel, R. E.; Backman, D. E.; Thakur, N.

    1998-01-01

    The ISOPHOT (Infrared Space Observatory Photometry) instrument onboard the Infrared Space Observatory (ISO) was used to obtain 3.6-90 micron photometry of Vega-type systems. Photometric data were calibrated with the ISOPHOT fine calibration source 1 (FCS1). Linear regression was used to derive transformations to make comparisons to ground-based and IRAS photometry systems possible. These transformations were applied to the photometry of 14 main-sequence stars. Details of these results are reported on.

  14. Isotopic assessment of sources and processes affecting sulfate and nitrate in surface water and groundwater of Luxembourg.

    PubMed

    Rock, L; Mayer, B

    2002-12-01

    Surface water and deep and shallow groundwater samples were taken from selected parts of the Grand-Duchy of Luxembourg to determine the isotopic composition of nitrate and sulfate, in order to identify sources and/or processes affecting these solutes. Deep groundwater had sulfate concentrations between 20 and 40 mg/L, delta34S(sulfate) values between -3.0 and -20.0 per thousand, and delta18O(sulfate) values between +1.5 and +5.0 per thousand; nitrate was characterized by concentrations varying between < 0.5 and 10 mg/L, delta15N(nitrate) values of approximately -0.5 per thousand, and delta18O(nitrate) values approximately +3.0 per thousand. In the shallow groundwater, sulfate concentrations ranged from 25 to 30 mg/L, delta34S(sulfate) values from -20.0 to +4.5 per thousand, and delta18O(sulfate) values from approximately +0.5 to +4.5 per thousand; nitrate concentrations varied between approximately 10 and 75 mg/L, delta15N(nitrate) values between +2.5 and +10.0 per thousand, and delta18O(nitrate) values between +1.0 and +3.0 per thousand. In surface water, sulfate concentrations ranged from 10 to 210 mg/L, delta34S(sulfate) values varied between -9.3 and +10.9 per thousand, and delta18O(sulfate) values between +3.0 and +10.7 per thousand were observed. Nitrate concentrations ranged from 10 to 40 mg/L, delta15N(nitrate) values from +6.5 to +12.0 per thousand, and delta18O(nitrate) values from -0.4 to +4.0 per thousand. Based on these data, three sulfate sources were identified controlling the riverine sulfate load. These are soil sulfate, dissolution of evaporites, and oxidation of reduced S minerals in the bedrock. Both groundwater types were predominantly influenced by sulfate from the two latter lithogenic S sources. The deep groundwater and a couple shallow groundwater samples had nitrate derived mainly from soil nitrification. All other sampling sites were influenced by nitrate originating from sewage and/or manure. A decrease in nitrate concentration observed along one of the rivers was attributed to denitrification. It appears that sulfate within Luxembourg's aquatic ecosystem is mainly of lithogenic origin, whereas nitrate is often derived from anthropogenic activities. PMID:12725423

  15. Characterization of Transiting Exoplanets by Way of Differential Photometry

    ERIC Educational Resources Information Center

    Cowley, Michael; Hughes, Stephen

    2014-01-01

    This paper describes a simple activity for plotting and characterizing the light curve from an exoplanet transit event by way of differential photometry analysis. Using free digital imaging software, participants analyse a series of telescope images with the goal of calculating various exoplanet parameters, including size, orbital radius and

  16. Comet Kohoutek. [proceedings - astronomical photometry/astronomical spectroscopy

    NASA Technical Reports Server (NTRS)

    Gary, G. A. (Editor)

    1975-01-01

    A compilation of scientific observations (workshop) is presented. Topics discussed are: (1) tail form, structure, and evolution; (2) hydroxyl related observations; (3) molecules and atoms in the coma and tail; (4) photometry and radiometry; and (5) spacecraft and ground based observation data. Color photographs are shown.

  17. Iontophoresis and Flame Photometry: A Hybrid Interdisciplinary Experiment

    ERIC Educational Resources Information Center

    Sharp, Duncan; Cottam, Linzi; Bradley, Sarah; Brannigan, Jeanie; Davis, James

    2010-01-01

    The combination of reverse iontophoresis and flame photometry provides an engaging analytical experiment that gives first-year undergraduate students a flavor of modern drug delivery and analyte extraction techniques while reinforcing core analytical concepts. The experiment provides a highly visual demonstration of the iontophoresis technique and…

  18. JCMT COADD: UKT14 continuum and photometry data reduction

    NASA Astrophysics Data System (ADS)

    Hughes, David; Oliveira, Firmin J.; Tilanus, Remo P. J.; Jenness, Tim

    2014-11-01

    COADD was used to reduce photometry and continuum data from the UKT14 instrument on the James Clerk Maxwell Telescope in the 1990s. The software can co-add multiple observations and perform sigma clipping and Kolmogorov-Smirnov statistical analysis. Additional information on the software is available in the JCMT Spring 1993 newsletter (large PDF).

  19. Photometry of Asteroids 558 Carmen, 613 Ginevra, and 1124 Stroobantia

    NASA Astrophysics Data System (ADS)

    Gil-Hutton, Ricardo

    1998-04-01

    CCD photometry of asteroids 558, 613 and 1124 are herein presented, which was obtained during four observing periods on 1993 and 1995. We have determined the following synodic rotational periods: 558 Carmen (9.264 +/- 0.005 hours), 613 Gineva (16.45 +/- 0.01 hours) and 1124 Stroobantia (16.39 +/- 0.01 hours).

  20. Iontophoresis and Flame Photometry: A Hybrid Interdisciplinary Experiment

    ERIC Educational Resources Information Center

    Sharp, Duncan; Cottam, Linzi; Bradley, Sarah; Brannigan, Jeanie; Davis, James

    2010-01-01

    The combination of reverse iontophoresis and flame photometry provides an engaging analytical experiment that gives first-year undergraduate students a flavor of modern drug delivery and analyte extraction techniques while reinforcing core analytical concepts. The experiment provides a highly visual demonstration of the iontophoresis technique and

  1. Characterization of Transiting Exoplanets by Way of Differential Photometry

    ERIC Educational Resources Information Center

    Cowley, Michael; Hughes, Stephen

    2014-01-01

    This paper describes a simple activity for plotting and characterizing the light curve from an exoplanet transit event by way of differential photometry analysis. Using free digital imaging software, participants analyse a series of telescope images with the goal of calculating various exoplanet parameters, including size, orbital radius and…

  2. Photoelectric photometry of J V. [Jupiter satellite Amalthea

    NASA Technical Reports Server (NTRS)

    Millis, R. L.

    1978-01-01

    UBV photometry of J V (Amalthea) near greatest western elongation shows this satellite to be about one magnitude fainter than previously believed. It is observed to be very red, having a B-V color index near + 1.5 mag. Unlike the Galilean satellites, J V appears to be a low-albedo object.

  3. Multiband photometry of PSNJ14102342-4318437 with OAUNI

    NASA Astrophysics Data System (ADS)

    Pereyra, A.; Cori, W.; Ricra, J.; Zevallos, M.; Tello, J.

    2016-01-01

    We report multiband photometry of Type Ib SN PSNJ14102342-4318437 (ATel #8415, ATel #8434, ATel #8437, ATel #8504) on 2016-01-10 (UT) gathered with the OAUNI 51cm telescope (Pereyra et al. 2015; arXiv:1512.03104) at Huancayo Observatory, Peru.

  4. Use of single-representative reverse-engineered surface-models for RSA does not affect measurement accuracy and precision.

    PubMed

    Seehaus, Frank; Schwarze, Michael; Flörkemeier, Thilo; von Lewinski, Gabriela; Kaptein, Bart L; Jakubowitz, Eike; Hurschler, Christof

    2016-05-01

    Implant migration can be accurately quantified by model-based Roentgen stereophotogrammetric analysis (RSA), using an implant surface model to locate the implant relative to the bone. In a clinical situation, a single reverse engineering (RE) model for each implant type and size is used. It is unclear to what extent the accuracy and precision of migration measurement is affected by implant manufacturing variability unaccounted for by a single representative model. Individual RE models were generated for five short-stem hip implants of the same type and size. Two phantom analyses and one clinical analysis were performed: "Accuracy-matched models": one stem was assessed, and the results from the original RE model were compared with randomly selected models. "Accuracy-random model": each of the five stems was assessed and analyzed using one randomly selected RE model. "Precision-clinical setting": implant migration was calculated for eight patients, and all five available RE models were applied to each case. For the two phantom experiments, the 95%CI of the bias ranged from -0.28 mm to 0.30 mm for translation and -2.3° to 2.5° for rotation. In the clinical setting, precision is less than 0.5 mm and 1.2° for translation and rotation, respectively, except for rotations about the proximodistal axis (<4.1°). High accuracy and precision of model-based RSA can be achieved and are not biased by using a single representative RE model. At least for implants similar in shape to the investigated short-stem, individual models are not necessary. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:903-910, 2016. PMID:26553748

  5. New Horizons disk-integrated approach photometry of Pluto and Charon

    NASA Astrophysics Data System (ADS)

    Zangari, Amanda M.; Buie, Marc W.; Buratti, Bonnie J.; Verbiscer, Anne J.; Howett, C. J. A.; Weaver, H. A.; Olkin, Catherine B.; Ennico, Kimberly; Young, Leslie A.; Stern, S. A.

    2015-11-01

    Approach and cruise observations of Pluto and Charon by NASA's New Horizons LOng Range Reconnaissance Imager ("LORRI") allow monitoring of Pluto not only at phase angles beyond Earth's 2 degree limit, but present a near constant sub-observer latitude of 43 degrees. However, the creation of light curves and solar phase curves of the pair prove to be an interesting challenge. Early images of the pair from July 2013 are barely resolved and have low signal, while later images show the pair clearly resolved and at sufficient resolution. Just at the Pluto approaches the signal level and image quality of prior HST images, surface features become resolved, rendering disk integrated photometry increasingly difficult and inaccurate, with the largest discrepancies found at longitudes which show the intersection of features informally named Tombaugh Regio ("the heart") and Cthulhu Macula ("the whale"). Now, post flyby, accurate knowledge of the radius and the shapes of surface features and their patterns of dark and light, allow for the creation of custom PSFs created from flyby maps. Using these maps, we present disk-integrated approach photometry, a solar phase curve and estimate Hapke parameters, taking into account the sub-observer position.This work was supported by the NASA New Horizons Project.

  6. Analysis of the DE CVn Photometry

    NASA Astrophysics Data System (ADS)

    Kolbin, A. I.

    2015-04-01

    The spottedness of the secondary component of a precataclysmic binary DE CVn has been investigated using the photometric data. A simultaneous analysis of the V and Rc light curves was carried out to map the stellar surface. Two different approaches were used for the starspot mapping. The first one is based on the approximation of the spottedness with circular spots. The idea of the second approach consists in partitioning the stellar surface into a grid of small areas. Over this grid a search for the continuous temperature distribution is carried out by the Tikhonov regularization algorithm.

  7. High-precision photometry by telescope defocusing - I. The transiting planetary system WASP-5

    NASA Astrophysics Data System (ADS)

    Southworth, John; Hinse, T. C.; Jrgensen, U. G.; Dominik, M.; Ricci, D.; Burgdorf, M. J.; Hornstrup, A.; Wheatley, P. J.; Anguita, T.; Bozza, V.; Novati, S. Calchi; Harpse, K.; Kjrgaard, P.; Liebig, C.; Mancini, L.; Masi, G.; Mathiasen, M.; Rahvar, S.; Scarpetta, G.; Snodgrass, C.; Surdej, J.; Thne, C. C.; Zub, M.

    2009-06-01

    We present high-precision photometry of two transit events of the extrasolar planetary system WASP-5, obtained with the Danish 1.54-m telescope at European Southern Obseratory La Silla. In order to minimize both random and flat-fielding errors, we defocused the telescope so its point spread function approximated an annulus of diameter 40 pixel (16 arcsec). Data reduction was undertaken using standard aperture photometry plus an algorithm for optimally combining the ensemble of comparison stars. The resulting light curves have point-to-point scatters of 0.50mmag for the first transit and 0.59mmag for the second. We construct detailed signal-to-noise ratio calculations for defocused photometry, and apply them to our observations. We model the light curves with the JKTEBOP code and combine the results with tabulated predictions from theoretical stellar evolutionary models to derive the physical properties of the WASP-5 system. We find that the planet has a mass of Mb = 1.637 +/- 0.075 +/- 0.033MJup, a radius of Rb = 1.171 +/- 0.056 +/- 0.012R Jup, a large surface gravity of gb = 29.6 +/- 2.8ms-2 and a density of ?b = 1.02 +/- 0.14 +/- 0.01?Jup (statistical and systematic uncertainties). The planet's high equilibrium temperature of Teq = 1732 +/- 80K makes it a good candidate for detecting secondary eclipses. Based on data collected by Microlensing Network for the Detection of Small Terrestrial Exoplanets (MiNDSTEp) with the Danish 1.54-m telescope at the ESO La Silla Observatory. E-mail: j.k.taylor@warwick.ac.uk Royal Society University Research Fellow.

  8. THE SIZE AND SURFACE COATING OF NANOSILVER DIFFERENTIALLY AFFECTS BIOLOGICAL ACTIVITY IN BLOOD BRAIN BARRIER (RBEC4) CELLS.

    EPA Science Inventory

    Linking the physical properties of nanoparticles with differences in their biological activity is critical for understanding their potential toxicity and mode of action. The influence of aggregate size, surface coating, and surface charge on nanosilver's (nanoAg) movement through...

  9. Crowded Field Photometry in the CLASH Clusters: Measuring the Red Sequence of Cluster Galaxies with Robust Photometry

    NASA Astrophysics Data System (ADS)

    Connor, Thomas; Donahue, Megan; Moustakas, John; Kelson, Daniel; Coe, Dan A.; Postman, Marc; CLASH Team

    2016-01-01

    The Cluster Lensing And Supernova survey with Hubble (CLASH) is an HST multi-cycle treasury program investigating 25 massive clusters of galaxies with X-ray gas Tx > 5 keV, spanning ~5 to ~30 x 10^14 solar masses, and a redshift range of 0.15 < z < 0.9. With 500 orbits of HST time and 16-filter, ultraviolet to infrared photometry of each cluster, this survey offers an unprecedented dataset for cluster galaxy photometry across a span of age and mass, but obtaining robust photometry for the cluster members has been hampered by the crowded field. We have developed a new technique to detect and define objects despite the presence of overlapping light profiles and to measure photometry of galaxies overlapping the extended haloes of massive galaxies. Utilizing spectral energy distribution fitting, we infer the properties of the detected galaxies, including their abundances and the time since their first star formation. Here we will discuss our technique and results, including the role metallicity and age play in shaping the red sequence of cluster galaxies.

  10. VizieR Online Data Catalog: JHKs photometry of IC 1396N (Beltran+, 2009)

    NASA Astrophysics Data System (ADS)

    Beltran, M. T.; Massi, F.; Lopez, R.; Girart, J. M.; Estalella, R.

    2009-04-01

    Table 1 contains the JHKs photometry and positions of found Ks sources detected in the three bands towards IC 1396N. Table 2 contains the JHKs photometry and positions of found Ks sources detected in the H and Ks bands. Table 3 contains the JHKs photometry and positions of sources only detected in the Ks band. Table 4 contains the JHKs photometry and positions of sources detected in the J and H bands. Table 5 contains the H2 photometry and positions of the knots. (5 data files).

  11. Cosmogenic dating ranging from 20 to 700 ka of a series of alluvial fan surfaces affected by the El Tigre fault, Argentina

    NASA Astrophysics Data System (ADS)

    Siame, Lionel L.; Bourlès, Didier L.; Sébrier, Michel; Bellier, Olivier; Castano, Juan Carlos; Araujo, Mario; Perez, Miguel; Raisbeck, Grant M.; Yiou, Françoise

    1997-11-01

    It is crucial to date continental landforms to quantify processes involved in terrestrial surface evolution, especially in regions affected by active tectonics. Andean quaternary alluvial fan surfaces affected by the El Tigre strike-slip fault have been studied using combined geomorphic and 10Be exposure age approaches. Field observations and SPOT (French acronym for “Satellite for Observation of the Earth”) image analysis enable the identification of six alluvial fan units. Measurements of in situ produced cosmogenic 10Be concentrations in quartzite boulders exposed on the top of fan surfaces show that the depositional periods ended during successive major interglacial stages. The calculated minimum exposure ages date the abandonments of the alluvial fan surface from 41 000 ± 8500 yr for the youngest to 670 000 ± 140 000 yr for the oldest unit. When linked to the measured maximum cumulative right-lateral displacement of stream channels, the exposure ages yield a horizontal slip rate of about 1 mm/yr on the El Tigre fault. This study shows that for arid regions, where fan surface erosion is minimal, in situ produced 10Be can be used to constrain the age of stratigraphically separate alluvial fan surfaces. These fan surface exposure ages can be further used to calculate slip rates on active faults and infer depositional periods correlative with climatic events.

  12. Near infrared photometry of comet C/2005 E2 (McNaught)

    NASA Astrophysics Data System (ADS)

    Picazzio, Enos; Figueredo, Elysandra; de Almeida, Amaury Augusto; de Oliveira, Claudia Mendes; Churyumov, Klim Ivanovich

    We present results of JHK photometry for comet C/2005 E2 (McNaught). Observations were made with the OSIRIS imager at the SOAR telescope, on Sept. 26-27, 2005. The dependence of the main parameters on the angular distance from the cometary photometric nucleus is discussed. We considered concentric rings around the photometric nucleus of the comet, with the radius determined by the aperture. Integrated flux in the ring, surface brightness, J-H and H-K color indices, and mean flux decay were obtained for each ring. A phometric radial profile was also obtained by tracing average values of the ace brightness for increasing values of radii in isophotes which allowed us to compute the azimuthally averaged surface brightness of the coma. The images centered on the photometric nucleus show three jets from active areas on the nucleus.

  13. CCD photometry of the Uranian satellites

    NASA Technical Reports Server (NTRS)

    Buratti, Bonnie J.; Gibson, James; Mosher, Joel A.

    1992-01-01

    Broadband V and R CCD observations of the Uranian satellite system have been obtained over the full range of solar phase angles observable from earth. These first visual observations of the phase curves of Miranda, Ariel, and Umbriel show that Ariel and Miranda exhibit the large opposition surges previously seen on the two outer Uranian Satellites. Umbriel, however, lacks an appreciable opposition surge; its surface is either extremely compact or consists of small particles which lack a backscattered component. The tenuous structure of the other satellites is most likely due to the effects of eons of meteoritic gardening.

  14. Factors affecting the wettability of different surface materials with vegetable oil at high temperatures and its relation to cleanability

    NASA Astrophysics Data System (ADS)

    Ashokkumar, Saranya; Adler-Nissen, Jens; Møller, Per

    2012-12-01

    The main aim of the work was to investigate the wettability of different surface materials with vegetable oil (olive oil) over the temperature range of 25-200 °C to understand the differences in cleanability of different surfaces exposed to high temperatures in food processes. The different surface materials investigated include stainless steel (reference), PTFE (polytetrafluoroethylene), silicone, quasicrystalline (Al, Fe, Cr) and ceramic coatings: zirconium oxide (ZrO2), zirconium nitride (ZrN) and titanium aluminum nitride (TiAlN). The ceramic coatings were deposited on stainless steel with two different levels of roughness. The cosine of the contact angle of olive oil on different surface materials rises linearly with increasing temperature. Among the materials analyzed, polymers (PTFE, silicone) gave the lowest cos θ values. Studies of the effect of roughness and surface flaws on wettability revealed that the cos θ values increases with increasing roughness and surface flaws. Correlation analysis indicates that the measured contact angle values gave useful information for grouping easy-clean polymer materials from the other materials; for the latter group, there is no direct relation between contact angle and cleanability. In addition to surface wettability with oil many other factors such as roughness and surface defects play an essential role in determining their cleanability.

  15. Cell sheet detachment affects the extracellular matrix: a surface science study comparing thermal liftoff, enzymatic, and mechanical methods.

    PubMed

    Canavan, Heather E; Cheng, Xuanhong; Graham, Daniel J; Ratner, Buddy D; Castner, David G

    2005-10-01

    This work compares the removal of bovine aortic endothelial cell (BAEC) monolayers via 1) low-temperature liftoff from a "smart polymer," plasma polymerized poly(N-isopropyl acrylamide) (ppNIPAM), 2) enzymatic digestion, and 3) mechanical dissociation from ppNIPAM surfaces. We examine the surfaces after cell removal by using X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), immunostaining, and cell adhesion assay. Immunoassay results indicate that low-temperature liftoff nondestructively harvests the cell sheet and most of the underlying extracellular matrix (ECM), whereas enzymatic digestion and mechanical dissociation are damaging to both the cells and ECM. XPS results indicate that amide and alcohol groups attributed to proteins in the ECM are present on postliftoff surfaces. Principal component analysis (PCA) of ToF-SIMS data indicates that molecular ion fragments of amino acids are present on postliftoff surfaces. Finally, a cell adhesion assay seeding new cells on surfaces from which an initial layer of cells was removed via each of the three methods indicates that liftoff and mechanical dissociation leave behind surfaces that better promote cell adhesion. We conclude that the removal of BAEC cells via low-temperature liftoff from ppNIPAM-treated surfaces is less damaging to the ECM proteins remaining at the surface than the other methods. PMID:16086418

  16. Volatile Organic Compound (VOC) emissions from feedlot pen surface materials as affected by within pen location, moisture, and temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A laboratory study was conducted to evaluate the effects of pen location, moisture, and temperature on emissions of volatile organic compounds (VOC) from surface materials obtained from feedlot pens where beef cattle were fed a diet containing 30% wet distillers grain plus solubles. Surface material...

  17. Copernicus spectra and infrared photometry of 42 Orionis

    NASA Technical Reports Server (NTRS)

    Johnson, H. M.; Snow, T. P., Jr.; Gehrz, R. D.; Hackwell, J. A.

    1977-01-01

    The Orion sword star 42 Ori is embedded in a nebula north of and separated from the Orion nebula. The B1 V star is probably normal. Other members of the multiple remain poorly defined, and the nebula may exhibit some peculiarities that may depend on them. Copernicus ultraviolet spectra of the star are described here, especially in the form of tables of wavelength identifications. The properties of the interstellar material in the line of sight are also discussed. Infrared photometry is presented which suggests that the ratio of total to selective extinction ranges from 3 to 3.5 for the interstellar matter in the direction of 42 Ori. The IR photometry provides no evidence for companion stellar or circumstellar components.

  18. High-speed multicolour photometry with CMOS cameras

    NASA Astrophysics Data System (ADS)

    Pokhvala, S. M.; Zhilyaev, B. E.; Reshetnyk, V. M.

    2012-11-01

    We present the results of testing the commercial digital camera Nikon D90 with a CMOS sensor for high-speed photometry with a small telescope Celestron 11'' at the Peak Terskol Observatory. CMOS sensor allows to perform photometry in 3 filters simultaneously that gives a great advantage compared with monochrome CCD detectors. The Bayer BGR colour system of CMOS sensors is close to the Johnson BVR system. The results of testing show that one can carry out photometric measurements with CMOS cameras for stars with the V-magnitude up to ≃14^{m} with the precision of 0.01^{m}. Stars with the V-magnitude up to ˜10 can be shot at 24 frames per second in the video mode.

  19. Millimeter-to-Far-Infrared Photometry of Cygnus A

    NASA Astrophysics Data System (ADS)

    Benford, Dominic J.; Staguhn, J.; Kovacs, A.; Sharp, E.; Maher, S.

    2013-01-01

    We present precision photometry and imaging of the core and two radio lobes of the galaxy Cygnus A at a wavelength of 2 millimeters, taken using the GISMO camera at the IRAM 30m telescope. We also present new 350 micron photometry using the SHARC-II camera at the CSO, archival Spitzer data, and WISE data, all with the aim of producing a precision spectral energy distribution of the synchrotron emission from the two radio lobes along with a single-dish size of the synchrotron-emitting regions. Using a sophisticated mapping approach and with attention to an accurate beamwidth measurement, we are able to determine that the two lobes have an effective emission scale of around 9+/-0.5 arcseconds, and are therefore roughly 10kpc in scale.

  20. CCD Photometry of Hubble's Variable Nebula, NGC 2261

    NASA Astrophysics Data System (ADS)

    Martin, B.; Bennum, D.; Rodrigue, M.; Colegrove, T.; Schultz, A.; Disanti, M.; Fink, U.

    1994-12-01

    We present BVRI photometry of R Mon/NGC 2261. The brightness variations of this system have been well documented and are believed to be the direct result of dark bodies orbiting R Mon and casting shadows upon the nebula. The apparent movement of the shadow boundaries suggest outward motion similar in character to a rotating beam of light from a lighthouse playing on cloud banks at different distances. We describe preliminary results of a project to study R Mon/NGC 2261 using CCD imaging data obtained during the period 1985-1988. The time based color analysis allows us to study spatially the changes in the light intensity from the nebula near R Mon. We present photometry from a data set obtained on December 5, 1988.

  1. Ultraviolet photometry of OB associations in M31

    NASA Technical Reports Server (NTRS)

    Hill, Jesse K.; Isensee, Joan E.; Bohlin, Ralph C.; O'Connell, Robert W.; Roberts, Morton S.; Smith, Andrew M.; Stecher, Theodore P.

    1993-01-01

    The study obtains near-UV and FUV magnitudes for 76 massive stars in 24 OB associations in the central and southern portions of M31 from images obtained by the Ultraviolet Imaging Telescope (UIT) during the Astro 1 spacelab mission. A comparison is made with the previous UIT photometry of 30 stars in the giant association NGC 206. Extinctions are estimated from the relation between E(B - V) and the distance from the center of M31 derived by Hodge and Lee (1988) from topical CCD stellar photometry. From evolutionary models, lower limits to the maximum stellar mass are estimated at about 60-100 solar masses in NGC 206, A29, A61, A63, A130, and A132. For other associations, the limits are in the range of about 20-55 solar masses.

  2. RASNZ Photometry Section, Incorporating the Auckland Photoelectric Observers' Group

    NASA Astrophysics Data System (ADS)

    Walker, S.

    2012-06-01

    (Abstract only) This review traces the development of amateur photoelectric and CCD photometry in New Zealand from its beginnings in the late 1960s at Christchurch and Auckland, through the Auckland Photoelectric Observers' Group and the RASNZ Photometry Section to its present place in Variable Stars South. For this period of over forty years the participants have been heavily involved with southern hemisphere variable star astronomy and observatories such as Carter, Mt. John, and Auckland, together with which were sponsored the highly successful photoelectric conferences, PEP 1-5. Samples of various projects are shown and described. The full text can be seen at http://www.variablestarssouth.org/index.php/community/member-publications/posters

  3. An Aperture Photometry Pipeline for K2 Data

    NASA Astrophysics Data System (ADS)

    Buzasi, Derek L.; Carboneau, Lindsey; Lezcano, Andy; Vydra, Ekaterina

    2016-01-01

    As part of an ongoing research program with undergraduate students at Florida Gulf Coast University, we have constructed an aperture photometry pipeline for K2 data. The pipeline performs dynamic automated aperture mask definition for all targets in the K2 fields, followed by aperture photometry and detrending. Our pipeline is currently used to support a number of projects, including studies of stellar rotation and activity, red giant asteroseismology, gyrochronology, and exoplanet searches. In addition, output is used to support an undergraduate class on exoplanets aimed at a student audience of both majors and non-majors. The pipeline is designed for both batch and single-target use, and is easily extensible to data from other missions, and pipeline output is available to the community. This paper will describe our pipeline and its capabilities and illustrate the quality of the results, drawing on all of the applications for which it is currently used.

  4. Absolute stellar photometry on moderate-resolution FPA images

    USGS Publications Warehouse

    Stone, T.C.

    2009-01-01

    An extensive database of star (and Moon) images has been collected by the ground-based RObotic Lunar Observatory (ROLO) as part of the US Geological Survey program for lunar calibration. The stellar data are used to derive nightly atmospheric corrections for the observations from extinction measurements, and absolute calibration of the ROLO sensors is based on observations of Vega and published reference flux and spectrum data. The ROLO telescopes were designed for imaging the Moon at moderate resolution, thus imposing some limitations for the stellar photometry. Attaining accurate stellar photometry with the ROLO image data has required development of specialized processing techniques. A key consideration is consistency in discriminating the star core signal from the off-axis point spread function. The analysis and processing methods applied to the ROLO stellar image database are described. ?? 2009 BIPM and IOP Publishing Ltd.

  5. Luminosities and temperatures of M dwarf stars from infrared photometry

    NASA Technical Reports Server (NTRS)

    Veeder, G. J.

    1974-01-01

    Bolometric magnitudes for a large number of M type dwarf stars, obtained by broadband infrared photometry at 1.65, 2.2, and 3.5 microns, are reviewed. The data obtained indicate that one parameter is sufficient to describe the blanketing in all of the UBVRI bands for all types of M dwarfs. In general, late M dwarfs seem to have lower effective temperatures than are predicted by theoretical models.

  6. Photometry of AMOR Asteroids 1036 Ganymede and 1139 Atami

    NASA Astrophysics Data System (ADS)

    Lupishko, D. F.; Velichko, F. P.; Shevchenko, V. G.

    1989-01-01

    UBV photometry was used to determine the light curves of the asteroids Ganymede (July to November, 1985) and Atami (October, 1986). Their amplitudes amount to 0.40 and greater than 0.18 m, respectively. Ganymede is found to have a period of 10 h 18.25 + or - 0.16 m and a straight direction of rotation. The probable value for the period of Atami is greater than about 20 h.

  7. PythonPhot: Simple DAOPHOT-type photometry in Python

    NASA Astrophysics Data System (ADS)

    Jones, David O.; Scolnic, Daniel M.; Rodney, Steven A.

    2015-01-01

    PythonPhot is a simple Python translation of DAOPHOT-type (ascl:1104.011) photometry procedures from the IDL AstroLib (Landsman 1993), including aperture and PSF-fitting algorithms, with a few modest additions to increase functionality and ease of use. These codes allow fast, easy, and reliable photometric measurements and are currently used in the Pan-STARRS supernova pipeline and the HST CLASH/CANDELS supernova analysis.

  8. Astronomical Photometry and the Legacy of Arne Henden (Abstract)

    NASA Astrophysics Data System (ADS)

    Joner, M.

    2015-06-01

    (Abstract only) Arne Henden has helped provide a valuable resource to the photometric community with the publication of the 1982 book Astronomical Photometry. I will present a brief review of the topics covered in this handbook and recount some of the many times that it has been useful to myself and my students for answering a wide variety of questions dealing with the acquisition and reduction of photometric observations.

  9. BVR photometry and CCD spectroscopy of nova Del 2013

    NASA Astrophysics Data System (ADS)

    Santangelo, M. M. M.; Pasquini, M.

    2013-08-01

    In the course of the CATS (Capannori Astronomical Transient Survey) project, M.M.M. Santangelo and M. Pasquini performed BVR photoelectric photometry and low resolution CCD long-slit spectrometry of nova Delphini 2013. The measurements were made with an Optec SSP-5A single channel photoelectric photometer (with a photomultiplier tube Hamamatsu R6358), and with a SBIG SGS spectrometer + CCD camera ST-7XME attached at OAC's 0.30-m f/10 Schmidt-Cassegrain telescope.

  10. Photometry and Other Characteristics of Venus

    NASA Astrophysics Data System (ADS)

    Schmude, Richard W., Jr.; Dutton, James

    2001-12-01

    New photoelectric magnitude measurements are reported and these values have been combined with previously reported measurements in the selection of the photometric constants of Venus. The selected normalized magnitudes of Venus are: B(1,0) = -3.42, V(1,0) = -4.25, R(1,0) = -4.87 and I(1,0) = -5.14, while the selected solar phase angle coefficients for the B, V, R and I filters are: 0.0055, 0.0063, 0.0071 and 0.0062. Dichotomy measurements made between 1919 and 2001 have been reviewed and it is concluded that the Schroeter effect is real and that it is primarily due to two factors: 1) twilight scattering and 2) shading near the terminator. We also conclude that there is no correlation between the Schroeter effect and the 11-year solar cycle and that there is no difference in the magnitude of the Schroeter effect between eastern and western apparitions. There does, however, appear to be a ~35 year cycle in the magnitude of the Schroeter effect during most of the Twentieth Century. We also conclude that the cusp extensions of Venus may affect the observed phase of that planet and that irregularities near the terminator suggest large-scale vertical cloud relief of about 2-5 kilometers.

  11. M2K Planet Search: Spectroscopic Screening and Transit Photometry

    NASA Astrophysics Data System (ADS)

    Mann, Andrew; Gaidos, E.; Fischer, D.; Lepine, S.

    2010-10-01

    The M2K project is a search for planets orbiting nearby early M and late K dwarf drawn from the SUPERBLINK catalog. M and K dwarfs are highly attractive targets for finding low-mass and habitable planets because (1) close-in planets are more likely to orbit within their habitable zone, (2) planets orbiting them induce a larger Doppler signal and have deeper transits than similar planets around F, G, and early K type stars, (3) planet formation models predict they hold an abundance of super-Earth sized planets, and (4) they represent the vast majority of the stars close enough for direct imaging techniques. In spite of this, only 10% of late K and early M dwarfs are being monitored by current Doppler surveys. As part of the M2K project we have obtained low-resolution spectra for more than 2000 of our sample of 10,000 M and K dwarfs. We vet our sample by screening these stars for high metallicity and low chromospheric activity. We search for transits on targets showing high RMS Doppler signal and photometry candidates provided by SuperWASP project. By using "snapshot” photometry have been able to achieve sub-millimag photometry on numerous transit targets in the same night. With further follow-up observations we will be able to detect planets smaller than 10 Earth masses.

  12. Night sky photometry with amateur-grade digital cameras

    NASA Astrophysics Data System (ADS)

    Mrozek, Tomasz; Gronkiewicz, Dominik; Kolomanski, Sylwester; Steslicki, Marek

    2015-08-01

    Measurements of night sky brightness can give us valuable information on light pollution. The more the measurements we have the better is our knowledge on the spatial distribution of the pollution on local and global scale.High accuracy professional photometry of night sky can be performed with dedicated instruments. The main drawbacks of this method are high price and low mobility. This limits an amount of observers and therefore amount of photometric data that can be collected. In order to overcome the problem of limited amount of data we can involve amateur astronomers in photometry of night sky. However, to achieve this goal we need a method that utilizes equipment which is usually used by amateur astronomers, e.g digital cameras.We propose a method that enables good accuracy photometry of night sky with a use of digital compact or DSLR cameras. In the method reduction of observations and standarization to Johnson UBV system are performed. We tested several cameras and compared results to Sky Quality Meter (SQM) measurements. The overall consistency for results is within 0.2 mag.

  13. QDPHOT : An IRAF Task for Quick &Dirty Photometry

    NASA Astrophysics Data System (ADS)

    Mighell, K. J.

    I presented a new fast CCD stellar photometry task for IRAF called QDPHOT (Quick & Dirty PHOTometry) which is designed to quickly produce good CCD stellar photometry for applications where speed matters and every second is important. QDPHOT currently detects and photometers stars present in two aligned CCD images with stellar full-width-at-half-maximum values of 2-3 pixels. QDPHOT typically takes just a few seconds to analyze a single CCD of two aligned WFPC2 observations in two filters [e.g. 2-3 seconds on a 200MHz Sun Ultra1 workstation]. QDPHOT is suitable for producing on-the-fly instrumental color-magnitude diagrams at the telescope console in the few seconds between CCD readouts. QDPHOT is also an excellent data mining tool for finding high-quality stellar observations amongst GB of archived data. As an example of using QDPHOT as a data mining tool, I presented many instrumental color-magnitude diagrams of globular clusters in the Milky Way and nearby galaxies which are based on archival WFPC2 observations obtained from the Hubble Space Telescope data archive. Typical reduction times for these WFPC2 observations was about 8-12 seconds per cluster CMD (all 4 WFPC2 CCDs). QDPHOT is currently packaged as part of the IRAF QDTOOLS package which is available at the following website: http://www.noao.edu/staff/mighell/qdtools/

  14. Transformed photometry of young stars in Cha requested

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2013-01-01

    Dr. Peter Abraham (Konkoly Observatory, Budapest, Hungary) requested the assistance of AAVSO observers in monitoring eight young stars in Chamaeleon in support of photometry he and his colleagues will be obtaining with the VLT/ISAAC (infrared) and Herschel Space Observatory (far-infrared) during January-February 2013. The targets are CR Cha, CT Cha, HP Cha (Glass I), VW Cha, VZ Cha, WW CHa, WX Cha, XX Cha. Calibrated, transformed VRI photometry is requested to precisely monitor changes in the optical brightness and colors of these objects. Calibration and transformation of the photometry is crucial - if all of the data are not on the same system and particularly if the colors are not transformed, it will be extremely difficult to correlate the data usefully. Previous observations indicate that the stars are highly variable. Brightness changes can be expected from a few tenths of a magnitude to up to 1-2 magnitudes on a timescale of a few days to a few weeks. Observers are asked to try to obtain one to two sets of VRI images per night. Finder charts with sequences may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

  15. Multi-channel fiber photometry for population neuronal activity recording

    PubMed Central

    Guo, Qingchun; Zhou, Jingfeng; Feng, Qiru; Lin, Rui; Gong, Hui; Luo, Qingming; Zeng, Shaoqun; Luo, Minmin; Fu, Ling

    2015-01-01

    Fiber photometry has become increasingly popular among neuroscientists as a convenient tool for the recording of genetically defined neuronal population in behaving animals. Here, we report the development of the multi-channel fiber photometry system to simultaneously monitor neural activities in several brain areas of an animal or in different animals. In this system, a galvano-mirror modulates and cyclically couples the excitation light to individual multimode optical fiber bundles. A single photodetector collects excited light and the configuration of fiber bundle assembly and the scanner determines the total channel number. We demonstrated that the system exhibited negligible crosstalk between channels and optical signals could be sampled simultaneously with a sample rate of at least 100 Hz for each channel, which is sufficient for recording calcium signals. Using this system, we successfully recorded GCaMP6 fluorescent signals from the bilateral barrel cortices of a head-restrained mouse in a dual-channel mode, and the orbitofrontal cortices of multiple freely moving mice in a triple-channel mode. The multi-channel fiber photometry system would be a valuable tool for simultaneous recordings of population activities in different brain areas of a given animal and different interacting individuals. PMID:26504642

  16. Multi-channel fiber photometry for population neuronal activity recording.

    PubMed

    Guo, Qingchun; Zhou, Jingfeng; Feng, Qiru; Lin, Rui; Gong, Hui; Luo, Qingming; Zeng, Shaoqun; Luo, Minmin; Fu, Ling

    2015-10-01

    Fiber photometry has become increasingly popular among neuroscientists as a convenient tool for the recording of genetically defined neuronal population in behaving animals. Here, we report the development of the multi-channel fiber photometry system to simultaneously monitor neural activities in several brain areas of an animal or in different animals. In this system, a galvano-mirror modulates and cyclically couples the excitation light to individual multimode optical fiber bundles. A single photodetector collects excited light and the configuration of fiber bundle assembly and the scanner determines the total channel number. We demonstrated that the system exhibited negligible crosstalk between channels and optical signals could be sampled simultaneously with a sample rate of at least 100 Hz for each channel, which is sufficient for recording calcium signals. Using this system, we successfully recorded GCaMP6 fluorescent signals from the bilateral barrel cortices of a head-restrained mouse in a dual-channel mode, and the orbitofrontal cortices of multiple freely moving mice in a triple-channel mode. The multi-channel fiber photometry system would be a valuable tool for simultaneous recordings of population activities in different brain areas of a given animal and different interacting individuals. PMID:26504642

  17. Galileo photometry of Apollo landing sites

    NASA Technical Reports Server (NTRS)

    Helfenstein, P.; Veverka, J.; Head, James W.; Pieters, C.; Pratt, S.; Mustard, J.; Klaasen, K.; Neukum, G.; Hoffmann, H.; Jaumann, R.

    1993-01-01

    As of December 1992, the Galileo spacecraft performed its second and final flyby (EM2), of the Earth-Moon system, during which it acquired Solid State Imaging (SSI) camera images of the lunar surface suitable for photometric analysis using Hapke's, photometric model. These images, together with those from the first flyby (EM1) in December 1989, provide observations of all of the Apollo landing sites over a wide range of photometric geometries and at eight broadband filter wavelengths ranging from 0.41 micron to 0.99 micron. We have completed a preliminary photometric analysis of Apollo landing sites visible in EM1 images and developed a new strategy for a more complete analysis of the combined EM1 and EM2 data sets in conjunction with telescopic observations and spectrogoniometric measurements of returned lunar samples. No existing single data set, whether from spacecraft flyby, telescopic observation, or laboratory analysis of returned samples, describes completely the light scattering behavior of a particular location on the Moon at all angles of incidence (i), emission (e), and phase angles (a). Earthbased telescopic observations of particular lunar sites provide good coverage of incidence nad phase angles, but their range in emission angle is limited to only a few degrees because of the Moon's synchronous rotation. Spacecraft flyby observations from Galileo are now available for specific lunar features at many photometric geometries unobtainable from Earth; however, this data set lacks coverage at very small phase angles (a less than 13 deg) important for distinguishing the well-known 'opposition effect'. Spectrogoniometric measurements from returned lunar samples can provide photometric coverage at almost any geometry; however, mechanical properties of prepared particulate laboratory samples, such as particle compaction and macroscopic roughness, likely differ from those on the lunar surface. In this study, we have developed methods for the simultaneous analysis of all three types of data: we combine Galileo and telescopic observations to obtain the most complete coverage with photometric geometry, and use spectrogoniometric observations of lunar soils to help distinguish the photometric effects of macroscopic roughness from those caused by particle phase function behavior (i.e., the directional scattering properties of regolith particles).

  18. FACTORS AFFECTING THE LONG-TERM RESPONSE OF SURFACE WATERS TO ACIDIC DEPOSITION: STATE-OF-THE-SCIENCE

    EPA Science Inventory

    Recent intensive study of the causes of surface water acidification has led to numerous hypothesized controlling mechanisms. Among these are the salt-effect reduction of alkalinity, the base cation buffering and sulfate adsorption capacities of soils, availability of weatherable ...

  19. Galileo photometry of asteroid 243 Ida

    USGS Publications Warehouse

    Helfenstein, P.; Veverka, J.; Thomas, P.C.; Simonelli, D.P.; Klaasen, K.; Johnson, T.V.; Fanale, F.; Granahan, J.; McEwen, A.S.; Belton, M.; Chapman, C.

    1996-01-01

    Galileo imaging observations over phase angles 19.5?? to 109.8?? are combined with near-opposition Earth-based data to derive the photometric properties of Ida. To first order these properties are uniform over the surface and well modeled at ?? = 0.55 ??m by Hapke parameters ????0 = 0.22, h = 0.020, B0 = 1.5, g = -0.33, and ?? = 18?? with corresponding geometric albedo p = 0.21??0.030.01 and Bond albedo AB = 0.081??0.0170.008. Ida's photometric properties are more similar to those of "average S-asteroids" (P. Helfenstein and J. Veverka 1989, Asteroids II, Univ. of Arizona Press, Tucson) than are those of 951 Gaspra. Two primary color units are identified on Ida: Terrain A exhibits a spectrum with relatively shallower 1-??m absorption and a relatively steeper red spectral slope than average Ida, while Terrain B has a deeper 1-??m absorption and a less steep red slope. The average photometric properties of Ida and Terrain A are similar while those of Terrain B differ mostly in having a slightly higher value of ????0 (0.22 versus 0.21), suggesting that Terrain B consists of slightly brighter, more transparent regolith particles. Galileo observations of Ida's satellite Dactyl over phase angles 19.5?? to 47.6?? suggest photometric characteristics similar to those of Ida, the major difference being Dactyl's slightly lower albedo (0.20 compared to 0.21). ?? 1990 Academic Press, Inc.

  20. High-Quality Broadband BVRI Photometry of Benchmark Open Clusters

    NASA Astrophysics Data System (ADS)

    Joner, Michael D.

    Photometric techniques are often used to observe stars and it can be demonstrated that fundamental stellar properties can be observationally determined using calibrated sets of photometric data. Many of the most powerful techniques utilized to calibrate stellar photometry employ the use of stars in clusters since the individual stars are believed to have many common properties such as age, composition, and approximate distance. Broadband photometric Johnson/Cousins BVRI observations are presented for several nearby open clusters. The new photometry has been tested for consistency relative to archival work and shown to be both accurate and precise. The careful use of a regular routine when making photometric observations, along with the monitoring of instrumental systems and the use of various quality control techniques when making observations or performing data reductions, will enhance an observer's ability to produce high-quality photometric measurements. This work contains a condensed review of the history of photometry, along with a brief description of several popular photometric systems that are often utilized in the field of stellar astrophysics. Publications written by Taylor or produced during the early Taylor and Joner collaboration are deemed especially relevant to the current work. A synopsis of seven archival publications is offered, along with a review of notable reports of VRI photometric observations for the nearby Hyades open star cluster. The body of this present work consists of four publications that appeared between the years 2005 and 2008, along with a soon to be submitted manuscript for a fifth publication. Each of these papers deals specifically with high-quality broadband photometry of open clusters with new data being presented for the Hyades, Coma, NGC 752, Praesepe, and M67. It is concluded that the VRI photometry produced during the Taylor and Joner collaborative investigations forms a high-quality data set that has been: (1) stable for a period of more than 25 years; (2) monitored and tested several times for consistency relative to the broadband Cousins system, and (3) shown to have well-understood transformations to other versions of broadband photometric systems. Further work is suggested for: (1) the transformation relationships for the reddest stars available for use as standards; (2) the standardization of more fields for use with CCD detectors; (3) a further investigation of transformations of blue color indices for observations done using CCD detectors with enhanced UV sensitivity, and (4) a continuation of work on methods to produce high-quality observations of assorted star clusters (both open and globular) with CCD-based instrumentation and intermediate-band photometric systems.

  1. Karl Schwarzschild's investigations of ``out-of-focus photometry'' between 1897-1899 and his contribution to photographic photometry

    NASA Astrophysics Data System (ADS)

    Habison, Peter

    From 1897 to 1899 Karl Schwarzschild was working at Kuffner Observatory in Vienna. During these years he developed new measuring techniques in the field of photographic photometry, where he particularly studied the quantitative determination of the departure of the reciprocity law during photographic exposures. During that time stellar magnitudes were almost exclusively determined by measuring the size of in-focus stellar disks. Photometry using out-of-focus exposures had been proposed, but had not yet been tried. Schwarzschild's very first paper in this context contains two important results: The intimation that estimating densities on out-of-focus plates could give an accuracy of better than 0.05 mag and the analysis of his photographic data indicated that the reciprocity law (S=Iṡ t), was not obeyed. >From the paper it is not clear how he came to set himself this double task. A series of singly exposed plates date from September 1897, whereas the series of exposures of particular relevance to the question of the time dependence of plate density all date from October 1897. It is remarkable how Schwarzschild succeeded in deriving a better approximation of the characteristic curve's dependence on intensity and time. The talk will focus on Schwarzschild's investigations of ``out-of-focus photometry'' between 1897 and 1899. A few selected original photographic plates will be presented and discussed.

  2. Characterization of surface properties affecting the activity of the 'free silica' fraction of respirable dusts. Final report

    SciTech Connect

    Wallace, W.E.; Keane, M.J.

    1988-01-01

    A two-part study was conducted to investigate the surface properties of the quartz or 'free silica' fraction of respirable mine dusts. The degree of surface contamination of respirable quartz particles was studied using scanning electron microscopy with energy-dispersive x-ray analysis (SEM-EDX) to distinguish alumino/silicate and magnesium silicate surface occlusions from the silicate particles. By varying the electron-beam accelerating voltage, the depth of penetration could be reduced, so that the surface layer could be distinguished from the substrate material. Experiments were conducted on the relationship of measured SEM-EDX signal coming from the substrate to coating thickness and electron-beam accelerating voltage. In the second part, modifications were made of respirable-quartz-particle cytotoxicity by surface treatment. As measured by erythrocyte hemolysis and pulmonary macrophage release of lactate dehydrogenase in-vitro, respirable quartz cytotoxicity was neutralized by boiling in water in glass test tubes for 10 to 40 minutes. The membranolytic potential was reduced to near zero by boiling up to 10 milligrams of quartz per milliliter of water. Replacing the medium with fresh water midway through the boiling resulted in full detoxification. Preboiling the medium with silica reduced the effect. Detoxification persisted after mild drying at 110 C for 8 hours and persisted after 3 days of resuspension in water at room temperature.

  3. BRITE-Constellation: Nanosatellites for precision photometry of bright stars

    NASA Astrophysics Data System (ADS)

    Weiss, W. W.; Moffat, A. F. J.; Schwarzenberg-Czerny, A.; Koudelka, O. F.; Grant, C. C.; Zee, R. E.; Kuschnig, R.; Mochnacki, St.; Rucinski, S. M.; Matthews, J. M.; Orleański, P.; Pamyatnykh, A. A.; Pigulski, A.; Alves, J.; Guedel, M.; Handler, G.; Wade, G. A.; Scholtz, A. L.; Scholtz

    2014-02-01

    BRITE-Constellation (where BRITE stands for BRIght Target Explorer) is an international nanosatellite mission to monitor photometrically, in two colours, brightness and temperature variations of stars brighter than V ~ 4, with precision and time coverage not possible from the ground. The current mission design consists of three pairs of 7 kg nanosats (hence ``Constellation'') from Austria, Canada and Poland carrying optical telescopes (3 cm aperture) and CCDs. One instrument in each pair is equipped with a blue filter; the other, a red filter. The first two nanosats (funded by Austria) are UniBRITE, designed and built by UTIAS-SFL (University of Toronto Institute for Aerospace Studies-Space Flight Laboratory) and its twin, BRITE-Austria, built by the Technical University Graz (TUG) with support of UTIAS-SFL. They were launched on 25 February 2013 by the Indian Space Agency, under contract to the Canadian Space Agency. Each BRITE instrument has a wide field of view (~ 24 degrees), so up to 15 bright stars can be observed simultaneously in 32 × 32 sub-rasters. Photometry (with reduced precision but thorough time sampling) of additional fainter targets will be possible through on-board data processing. A critical technical element of the BRITE mission is the three-axis attitude control system to stabilize a nanosat with very low inertia. The pointing stability is better than 1.5 arcminutes rms, a significant advance by UTIAS-SFL over any previous nanosatellite. BRITE-Constellation will primarily measure p- and g-mode pulsations to probe the interiors and ages of stars through asteroseismology. The BRITE sample of many of the brightest stars in the night sky is dominated by the most intrinsically luminous stars: massive stars seen at all evolutionary stages, and evolved medium-mass stars at the very end of their nuclear burning phases (cool giants and AGB stars). The Hertzsprung-Russell diagram for stars brighter than mag V=4 from which the BRITE-Constellation sample will be selected is shown in Fig. 1. This sample falls into two principal classes of stars: (1) Hot luminous H-burning stars (O to F stars). Analyses of OB star variability have the potential to help solve two outstanding problems: the sizes of convective (mixed) cores in massive stars and the influence of rapid rotation on their structure and evolution. (2) Cool luminous stars (AGB stars, cool giants and cool supergiants). Measurements of the time scales involved in surface granulation and differential rotation will constrain turbulent convection models. Mass loss from these stars (especially the massive supernova progenitors) is a major contributor to the evolution of the interstellar medium, so in a sense, this sample dominates cosmic ``ecology'' in terms of future generations of star formation. The massive stars are believed to share many characteristics of the lower mass range of the first generation of stars ever formed (although the original examples are of course long gone). BRITE observations will also be used to detect some Jupiter- and even Neptune-sized planets around bright host stars via transits, as expected on the basis of statistics from the Kepler exoplanet mission. Detecting planets around such very bright stars will greatly facilitate their subsequent characterization. BRITE will also use surface spots to investigate stellar rotation. The following Table summarizes launch and orbit parameters of BRITE-Constellation components. The full version of this paper describing in more detail BRITE-Constellation will be published separately in a journal. The symposium presentation is available at http://iaus301.astro.uni.wroc.pl/program.php

  4. Analysis of Factors Affecting Surface Expression and Immunogenicity of Recombinant Proteins Expressed by Gram-Positive Commensal Vectors

    PubMed Central

    Bolken, Tové C.; Franke, Christine A.; Jones, Kevin F.; Bell, Richard H.; Swanson, Ryan M.; King, David S.; Fischetti, Vincent A.; Hruby, Dennis E.

    2002-01-01

    Several key protein structural attributes were altered in an effort to optimize expression and immunogenicity of a foreign protein (M protein from Streptococcus pyogenes) exposed on the surface of Streptococcus gordonii commensal bacterial vectors: (i) a shorter N-terminal region, (ii) the addition of a 94-amino-acid spacer, and (iii) the addition of extra C-repeat regions (CRR) from the M6 protein. A decrease in the amount of cell surface M6 was observed upon deletion of 10 or more amino acid residues at the N terminus. On the other hand, reactivity of monoclonal antibody to surface M6 increased with the addition of the spacer adjacent to the proline- and glycine-rich region, and an increase in epitope dosage was obtained by adding another CRR immediately downstream of the original CRR. The results obtained should facilitate the design of improved vaccine candidates using this antigen delivery technology. PMID:11953386

  5. Analysis of factors affecting surface expression and immunogenicity of recombinant proteins expressed by gram-positive commensal vectors.

    PubMed

    Bolken, Tové C; Franke, Christine A; Jones, Kevin F; Bell, Richard H; Swanson, Ryan M; King, David S; Fischetti, Vincent A; Hruby, Dennis E

    2002-05-01

    Several key protein structural attributes were altered in an effort to optimize expression and immunogenicity of a foreign protein (M protein from Streptococcus pyogenes) exposed on the surface of Streptococcus gordonii commensal bacterial vectors: (i) a shorter N-terminal region, (ii) the addition of a 94-amino-acid spacer, and (iii) the addition of extra C-repeat regions (CRR) from the M6 protein. A decrease in the amount of cell surface M6 was observed upon deletion of 10 or more amino acid residues at the N terminus. On the other hand, reactivity of monoclonal antibody to surface M6 increased with the addition of the spacer adjacent to the proline- and glycine-rich region, and an increase in epitope dosage was obtained by adding another CRR immediately downstream of the original CRR. The results obtained should facilitate the design of improved vaccine candidates using this antigen delivery technology. PMID:11953386

  6. Immune Evasion Proteins of Murine Cytomegalovirus Preferentially Affect Cell Surface Display of Recently Generated Peptide Presentation Complexes?

    PubMed Central

    Lemmermann, Niels A. W.; Gergely, Kerstin; Bhm, Verena; Deegen, Petra; Dubner, Torsten; Reddehase, Matthias J.

    2010-01-01

    For recognition of infected cells by CD8 T cells, antigenic peptides are presented at the cell surface, bound to major histocompatibility complex class I (MHC-I) molecules. Downmodulation of cell surface MHC-I molecules is regarded as a hallmark function of cytomegalovirus-encoded immunoevasins. The molecular mechanisms by which immunoevasins interfere with the MHC-I pathway suggest, however, that this downmodulation may be secondary to an interruption of turnover replenishment and that hindrance of the vesicular transport of recently generated peptide-MHC (pMHC) complexes to the cell surface is the actual function of immunoevasins. Here we have used the model of murine cytomegalovirus (mCMV) infection to provide experimental evidence for this hypothesis. To quantitate pMHC complexes at the cell surface after infection in the presence and absence of immunoevasins, we generated the recombinant viruses mCMV-SIINFEKL and mCMV-?m06m152-SIINFEKL, respectively, expressing the Kb-presented peptide SIINFEKL with early-phase kinetics in place of an immunodominant peptide of the viral carrier protein gp36.5/m164. The data revealed ?10,000 Kb molecules presenting SIINFEKL in the absence of immunoevasins, which is an occupancy of ?10% of all cell surface Kb molecules, whereas immunoevasins reduced this number to almost the detection limit. To selectively evaluate their effect on preexisting pMHC complexes, cells were exogenously loaded with SIINFEKL peptide shortly after infection with mCMV-SIINFEKA, in which endogenous presentation is prevented by an L174A mutation of the C-terminal MHC-I anchor residue. The data suggest that pMHC complexes present at the cell surface in advance of immunoevasin gene expression are downmodulated due to constitutive turnover in the absence of resupply. PMID:19906905

  7. Surface pressure affects B-hordein network formation at the air-water interface in relation to gastric digestibility.

    PubMed

    Yang, Jingqi; Huang, Jun; Zeng, Hongbo; Chen, Lingyun

    2015-11-01

    Protein interfacial network formation under mechanical pressure and its influence on degradation was investigated at molecular level using Langmuir-Blodgett B-hordein monolayer as a 2D model. Surface properties, such as surface pressure, dilatational and shear rheology and the surface pressure-area (π-A) isotherm, of B-hordein at air-water interface were analyzed by tensiometer, rheometer and a Langmuir-Blodgett trough respectively. B-Hordein conformation and orientation under different surface pressures were determined by polarization modulation-infrared reflection absorption spectroscopy (PM-IRRAS). The interfacial network morphology was observed by atomic force microscopy (AFM). B-Hordein could reduce the air-water surface tension rapidly to ∼45mN/m and form a solid-like network with high rheological elasticity and compressibility at interface, which could be a result of interactions developed by intermolecular β-sheets. The results also revealed that B-hordein interfacial network switched from an expanded liquid phase to a solid-like film with increasing compression pressure. The orientation of B-hordein was parallel to the surface when in expended liquid phase, whereas upon compression, the hydrophobic repetitive region tilted away from water phase. When compressed to 30mN/m, a strong elastic network was formed at the interface, and it was resistant to a harsh gastric-like environment of low pH and pepsin. This work generated fundamental knowledge, which suggested the potential to design B-hordein stabilized emulsions and encapsulations with controllable digestibility for small intestine targeted delivery of bioactive compounds. PMID:26342324

  8. Chronic topical application of all-trans-retinoic acid in man does not affect corneocyte surface area.

    PubMed

    Robinson, S M; Poncet, M; Ferracin, J; Czernielewski, J; Verschoore, M

    1994-01-01

    The potential therapeutic activity of topically applied novel analogues of retinoic acid is currently measured in many different animal models. In most cases, the technique used is invasive and biopsy specimens are required. Furthermore, efficacy in these models is not a guarantee of success in treatment of humans. Therefore, predictive human pharmacology tests are required in order to quantify a retinoid effect on human skin before conducting large clinical trials. The aim of this study was to determine whether changes in corneocyte surface area could be used as a predictive measure for the efficacy of topical retinoids in man. Topical applications of all-trans retinoic acid gel (Aberel), salicylic acid gel and the gel vehicle were made once daily for 4 weeks to skin of the lumbar region of healthy human volunteers. Corneocytes were recovered from these three treated zones as well as from one zone of untreated skin, and their surface areas were measured by image analysis using a MOP-Videoplan. The results showed that at no point during the 4 weeks of daily application to healthy human skin was there a statistically significant difference in the surface area of corneocytes recovered from Aberel, salicylic acid-, vehicle-treated or untreated sites. No specific effect of retinoic acid could be detected. However, although no between-treatment differences were found, significant cyclical changes in the mean surface areas with respect to baseline were observed. PMID:8024798

  9. Rhomboid 4 (ROM4) Affects the Processing of Surface Adhesins and Facilitates Host Cell Invasion by Toxoplasma gondii

    PubMed Central

    Buguliskis, Jeffrey S.; Brossier, Fabien; Shuman, Joel; Sibley, L. David

    2010-01-01

    Host cell attachment by Toxoplasma gondii is dependent on polarized secretion of apical adhesins released from the micronemes. Subsequent translocation of these adhesive complexes by an actin-myosin motor powers motility and host cell invasion. Invasion and motility are also accompanied by shedding of surface adhesins by intramembrane proteolysis. Several previous studies have implicated rhomboid proteases in this step; however, their precise roles in vivo have not been elucidated. Using a conditional knockout strategy, we demonstrate that TgROM4 participates in processing of surface adhesins including MIC2, AMA1, and MIC3. Suppression of TgROM4 led to decreased release of the adhesin MIC2 into the supernatant and concomitantly increased the surface expression of this and a subset of other adhesins. Suppression of TgROM4 resulted in disruption of normal gliding, with the majority of parasites twirling on their posterior ends. Parasites lacking TgROM4 bound better to host cells, but lost the ability to apically orient and consequently most failed to generate a moving junction; hence, invasion was severely impaired. Our findings indicate that TgROM4 is involved in shedding of micronemal proteins from the cell surface. Down regulation of TgROM4 disrupts the normal apical-posterior gradient of adhesins that is important for efficient cell motility and invasion of host cells by T. gondii. PMID:20421941

  10. Photometry from Voyager 2 - Initial results from the Uranian atmosphere, satellites, and rings

    NASA Technical Reports Server (NTRS)

    Lane, A. L.; West, R. A.; Nelson, R. M.; Wallis, B. D.; Buratti, B. J.; Horn, L. J.; Hord, C. W.; Esposito, L. W.; Simmons, K. E.; Graps, A. L.

    1986-01-01

    The results of Voyager 2 photopolarimetry (PPS) surveys of Uranus, the ring system, occultation experiments and observations of the Uranian moons are reported. Dual-channel photometry and polarimetry data obtained of the atmosphere at various emission and phase angles are delineated and compared with characteristics of the Saturn and Jupiter atmospheres. The results of temperature, UV absorption and density profile calculations are also discussed. Extensive ring dimensional data, based on two occultation experiments, are provided in tabular form noting that the rings contain no dust. Finally, the geometric albedos of the five major moons and the phase curve of the moon Titania are presented. The latter data indicate that Titanian surface features are not the result of recent events such as volcanism or ice slurry outflows.

  11. Large-scale stress factors affecting coral reefs: open ocean sea surface temperature and surface seawater aragonite saturation over the next 400 years

    NASA Astrophysics Data System (ADS)

    Meissner, K. J.; Lippmann, T.; Sen Gupta, A.

    2012-06-01

    One-third of the world's coral reefs have disappeared over the last 30 years, and a further third is under threat today from various stress factors. The main global stress factors on coral reefs have been identified as changes in sea surface temperature (SST) and changes in surface seawater aragonite saturation (Ωarag). Here, we use a climate model of intermediate complexity, which includes an ocean general circulation model and a fully coupled carbon cycle, in conjunction with present-day observations of inter-annual SST variability to investigate three IPCC representative concentration pathways (RCP 3PD, RCP 4.5, and RCP 8.5), and their impact on the environmental stressors of coral reefs related to open ocean SST and open ocean Ωarag over the next 400 years. Our simulations show that for the RCP 4.5 and 8.5 scenarios, the threshold of 3.3 for zonal and annual mean Ωarag would be crossed in the first half of this century. By year 2030, 66-85% of the reef locations considered in this study would experience severe bleaching events at least once every 10 years. Regardless of the concentration pathway, virtually every reef considered in this study (>97%) would experience severe thermal stress by year 2050. In all our simulations, changes in surface seawater aragonite saturation lead changes in temperatures.

  12. Comparison of ozone determinations by ultraviolet photometry and gas-phase titration

    NASA Technical Reports Server (NTRS)

    Demore, W. B.; Patapoff, M.

    1976-01-01

    A comparison of ozone determinations based on ultraviolet absorption photometry and gas-phase titration (GPT) shows good agreement between the two methods. Together with other results, these findings indicate that three candidate reference methods for ozone, UV photometry, IR photometry, and GPT are in substantial agreement. However, the GPT method is not recommended for routine use by air pollution agencies for calibration of ozone monitors because of susceptibility to experimental error.

  13. Detoxification of Implant Surfaces Affected by Peri-Implant Disease: An Overview of Non-surgical Methods

    PubMed Central

    Valderrama, Pilar; Blansett, Jonathan A; Gonzalez, Mayra G; Cantu, Myrna G; Wilson, Thomas G

    2014-01-01

    Objective: The aim of this review is to summarize the findings of studies that have evaluated non-surgical approaches for detoxification of implant body surfaces in vitro and in vivo, and to evaluate clinical trials on the use of these methodologies for treating peri-implant disease. Materials and methods: A literature search was conducted using MEDLINE (Pubmed) from 1966 to 2013. In vitro and in vivo studies as well as clinical trials on non-surgical therapy were evaluated. The outcome variables were the ability of the therapeutic method to eliminate the biofilm and endotoxins from the implant surface, the changes in clinical parameters including probing depth, clinical attachment levels, bleeding on probing; radiographic bone fill and histological re-osseointegration. Results: From 134 articles found 35 were analyzed. The findings, advantages and disadvantages of using lasers as well as mechanical and chemical methods are discussed. Most of the in vivo and human studies used combination therapies which makes determining the efficacy of one specific method difficult. Most human studies are case series with short term longitudinal analysis without survival or failure reports. Conclusion: Complete elimination of the biofilms is difficult to achieve using these approaches. All therapies induce changes of the chemical and physical properties of the implant surface. Re-osseointegration may be difficult to achieve if not impossible without surgical access to ensure thorough debridement of the defect and detoxification of the implant surface. Combination protocols for non-surgical treatment of peri-implantitis in humans have shown some positive clinical results but long-term evaluation to evaluate the validity and reliability of the techniques is needed. PMID:24894571

  14. Occurrence of near-surface ozone depletion in the Arctic spring strongly affected by Northern-Hemispheric climate variability

    NASA Astrophysics Data System (ADS)

    Koo, J.; Wang, Y.; Jiang, T.; Deng, Y.; Oltmans, S. J.; Solberg, S.

    2013-12-01

    In the Arctic spring, near-surface ozone can decrease to extremely low levels due to chemical removal catalyzed by halogen radicals. These ozone depletion events (ODEs) are usually accompanied by greatly enhanced surface deposition of reactive gaseous mercury. Here we show the effects of regional climate variability on Arctic ODE frequencies by analyzing surface ozone measurements at three monitoring sites (Barrow, Alert, and Zeppelinfjellet) in the past 30 years. Among the various climate variability indices, the Western Pacific (WP) index has the most significant impact. In years with high ODE frequencies at Barrow and Alert in April, the WP teleconnection pattern tends to be in its negative phase with a weakened storm track from the western Pacific to the Arctic and a strengthened subtropical jet across the Pacific, reducing transport of ozone-rich air masses from mid-latitudes to the Arctic. Analysis of the observations at Zeppelinfjellet indicates a much stronger influence of WP pattern in the 2000s than 1990s. Consequently, the WP index may be used as a proxy to assess ODE frequencies and subsequent environmental impacts in future climate projections.

  15. Cell surface localization of importin α1/KPNA2 affects cancer cell proliferation by regulating FGF1 signalling

    PubMed Central

    Yamada, Kohji; Miyamoto, Yoichi; Tsujii, Akira; Moriyama, Tetsuji; Ikuno, Yudai; Shiromizu, Takashi; Serada, Satoshi; Fujimoto, Minoru; Tomonaga, Takeshi; Naka, Tetsuji; Yoneda, Yoshihiro; Oka, Masahiro

    2016-01-01

    Importin α1 is involved in nuclear import as a receptor for proteins with a classical nuclear localization signal (cNLS). Here, we report that importin α1 is localized to the cell surface in several cancer cell lines and detected in their cultured medium. We also found that exogenously added importin α1 is associated with the cell membrane via interaction with heparan sulfate. Furthermore, we revealed that the cell surface importin α1 recognizes cNLS-containing substrates. More particularly, importin α1 bound directly to FGF1 and FGF2, secreted cNLS-containing growth factors, and addition of exogenous importin α1 enhanced the activation of ERK1/2, downstream targets of FGF1 signalling, in FGF1-stimulated cancer cells. Additionally, anti-importin α1 antibody treatment suppressed the importin α1−FGF1 complex formation and ERK1/2 activation, resulting in decreased cell growth. This study provides novel evidence that functional importin α1 is located at the cell surface, where it accelerates the proliferation of cancer cells. PMID:26887791

  16. High-precision photometry for K2 Campaign 1

    NASA Astrophysics Data System (ADS)

    Huang, C. X.; Penev, K.; Hartman, J. D.; Bakos, G. Á.; Bhatti, W.; Domsa, I.; de Val-Borro, M.

    2015-12-01

    The two reaction wheel K2 mission promises and has delivered new discoveries in the stellar and exoplanet fields. However, due to the loss of accurate pointing, it also brings new challenges for the data reduction processes. In this paper, we describe a new reduction pipeline for extracting high-precision photometry from the K2 data set, and present public light curves for the K2 Campaign 1 target pixel data set. Key to our reduction is the derivation of global astrometric solutions from the target stamps, from which accurate centroids are passed on for high-precision photometry extraction. We extract target light curves for sources from a combined UCAC4 and EPIC catalogue - this includes not only primary targets of the K2 campaign 1, but also any other stars that happen to fall on the pixel stamps. We provide the raw light curves, and the products of various detrending processes aimed at removing different types of systematics. Our astrometric solutions achieve a median residual of ˜0.127 arcsec. For bright stars, our best 6.5 h precision for raw light curves is ˜20 parts per million (ppm). For our detrended light curves, the best 6.5 h precision achieved is ˜15 ppm. We show that our detrended light curves have fewer systematic effects (or trends, or red-noise) than light curves produced by other groups from the same observations. Example light curves of transiting planets and a Cepheid variable candidate, are also presented. We make all light curves public, including the raw and detrended photometry, at http://k2.hatsurveys.org.

  17. Photometry and spectroscopy in the open cluster alpha Persei, 2.

    NASA Technical Reports Server (NTRS)

    Prosser, Charles F.

    1994-01-01

    Results from a combination of new spectroscopic and photometric observations in the lower main sequence and pre-main sequence of the open cluster alpha Persei are presented. New echelle spectroscopy has provided radial and rotational velocity information for thirteen candidate members, three of which are nonmembers based on radial velocity, absence of a Li 6707 A feature, and absence of H alpha emission. A set of revised rotational velocity estimates for several slowly rotating candidates identified earlier is given, yielding rotational velocities as low as 7 km/s for two apparent cluster members. VI photometry for several pre-main-sequence members is given; the new (V, V-I(sub K) photometry yields a more clearly defined pre-main sequence. A list of approximately 30 new faint candidate members based on the (V, V-I(sub K)), charge coupled device (CCD) photometry is presented in an effort to identify additional cluster members at very low masses. Low-dispersion spectra obtained for several of these candidates provide in some cases supporting evidence for cluster membership. The single brown dwarf candidate in this cluster is for the first time placed in a color-magnitude diagram with other cluster members, providing a better means for establishing its true status. Stars from among the list of new photometric candidates may provide the means for establishing a sequence of cluster members down to very faint magnitudes (V approximately 21) and consequently very low masses. New coordinate determinations for previous candidate members and finding charts for the new photometric candidates are provided in Appendices.

  18. Identifying Subluminous M Stars Using Three Color Photometry

    NASA Astrophysics Data System (ADS)

    Robertson, Thomas H.; Thompson, S. K.; Thompson, D. L.

    2013-06-01

    Subdwarf stars are stars that appear below the main sequence in a color-magnitude diagram for the most common stars which make up the disk of our galaxy. The present criteria for identifying red subdwarfs vary based on the observational data. Typically, stars have been classified as subdwarfs if they were faint with high proper motions. It is also known that subdwarfs are metal poor and can be identified by visual inspection of their spectra as well. By examining a red star’s relative TiO5 and CaH abundances in digital spectra, it can be classified as subdwarf. Such classification requires the acquisition and analysis of digital spectra which is very time consuming. This project attempted to determine if these stars can be objectively identified using three-color photometry. The three-color photometry compares broad band R and I colors and intermediate-band CaH observations. This photometry, developed at Ball State University, has been shown to be effective and efficient in luminosity classification (distinguishing between giant and dwarf stars) and in estimating distances to red dwarf stars. Observations of red dwarfs and subdwarfs made using the 0.9-m telescope of the Southeastern Association for Research in Astronomy (SARA) showed that stars in the color range 0.9 < R-I < 1.4 can be identified as subluminous using their position in the (R-CaH) - (R-I) two-color diagram. This information can be very helpful in identifying subdwarf stars in photometric surveys for red dwarf stars and in reducing systematic errors in their photometric parallaxes.

  19. Photometry and spectroscopy in the open cluster Alpha Persei, 2

    NASA Technical Reports Server (NTRS)

    Prosser, Charles F.

    1993-01-01

    Results from a combination of new spectroscopic and photometric observations in the lower main-sequence and pre-main sequence of the open cluster alpha Persei are presented. New echelle spectroscopy has provided radial and rotational velocity information for thirteen candidate members, three of which are nonmembers based on radial velocity, absence of a Li 6707A feature, and absence of H-alpha emission. A set of revised rotational velocity estimates for several slowly rotating candidates identified earlier is given, yielding rotational velocities as low as 7 km/s for two apparent cluster members. VRI photometry for several pre-main sequence members is given; the new (V,V-I(sub K)) photometry yields a more clearly defined pre-main sequence. A list of approximately 43 new faint candidate members based on the (V,V-I(sub K)) CCD photometry is presented in an effort to identify additional cluster members at very low masses. Low-dispersion spectra obtained for several of these candidates provide in some cases supporting evidence for cluster membership. The single brown dwarf candidate in this cluster is for the first time placed in a color-magnitude diagram with other cluster members, providing a better means for establishing its true status. Stars from among the list of new photometric candidates may provide the means for establishing a sequence of cluster members down to very faint magnitudes (V approximately 21) and consequently very low masses. New coordinate determinations for previous candidate members and finding charts for the new photometric candidates are provided in appendices.

  20. CCD-photometry of comets at large heliocentric distances

    NASA Technical Reports Server (NTRS)

    Mueller, Beatrice E. A.

    1992-01-01

    CCD imaging and time series photometry are used to determine the state of activity, nuclear properties and eventually the rotational motion of cometary nuclei. Cometary activity at large heliocentric distances and mantle evolution are not yet fully understood. Results of observations carried out at the 2.1 telescope on Kitt Peak April 10-12 and May 15-16, 1991 are discussed. Color values and color-color diagrams are presented for several comets and asteroids. Estimations of nuclear radii and shapes are given.

  1. Multicolor Photometry of the Uranus Irregular Satellites Sycorax and Caliban

    NASA Astrophysics Data System (ADS)

    Maris, Michele; Carraro, Giovanni; Cremonese, Gabriele; Fulle, Marco

    2001-05-01

    We report on accurate BVRI photometry for the two Uranian irregular satellites Sycorax and Caliban. We derive colors showing that Sycorax is bluer than Caliban. Our data allow us to detect a significant variability in Caliban's light curve, which suggests an estimated period of about 3 hr. Although it is the brighter of the two bodies, Sycorax does not display a strong, statistically significant variability. However, our data seem to suggest a period of about 4 hr. Based on observations carried out at ESO La Silla (Chile). See the Asteroid Properties Database (1993), http://pdssbn.astro.umd.edu/sbnhtml/.

  2. Refined flicker photometry technique to measure ocular lens density.

    PubMed

    Teikari, Petteri; Najjar, Raymond P; Knoblauch, Kenneth; Dumortier, Dominique; Cornut, Pierre-Loïc; Denis, Philippe; Cooper, Howard M; Gronfier, Claude

    2012-11-01

    Many physiological and pathological conditions are associated with a change in the crystalline lens transmittance. Estimates of lens opacification, however, generally rely on subjective rather than objective measures in clinical practice. The goal of our study was to develop an improved psychophysical heterochromatic flicker photometry technique combined with existing mathematical models to evaluate the spectral transmittance of the human ocular media noninvasively. Our results show that it is possible to accurately estimate ocular media density in vivo in humans. Potential applications of our approach include basic research and clinical settings on visual and nonimage-forming visual systems. PMID:23201811

  3. LEMON: an (almost) completely automated differential-photometry pipeline

    NASA Astrophysics Data System (ADS)

    Terrón, V.; Fernández, M.

    2011-11-01

    We present LEMON, the CCD differential-photometry pipeline, written in Python, developed at the Institute of Astrophysics of Andalusia (CSIC) and originally designed for its use at the 1.23 m CAHA telescope for automated variable stars detection and analysis. The aim of our tool is to make it possible to completely reduce thousands of images of time series in a matter of hours and with minimal user interaction, if not none at all, automatically detecting variable stars and presenting the results to the astronomer.

  4. Coordinates and RI photometry of Large Magellanic Cloud carbon stars

    SciTech Connect

    Costa, E. )

    1990-07-01

    Coordinates and photoelectric RI magnitudes are given for 86 carbon stars discovered by Blanco et al. in four selected 0.12 deg sq areas of the LMC. A comparison with the photometry of Blanco et al. for carbon stars in three different fields of the LMC suggests that the luminosity distribution of the carbon stars may change from center to center in the LMC. This possibility is supported by the differences in the mean I magnitude of the carbon stars detected between the four areas studied. 16 refs.

  5. Deep NIR photometry of the globular 47Tuc.

    NASA Astrophysics Data System (ADS)

    Troisi, L.; Bono, G.; Dall'Ora, M.; Calamida, A.; Di Cecco, A.; Iannicola, G.; Sanna, N.; Stetson, P. B.; Buonanno, R.; Caputo, F.; Corsi, C. E.; Degl'Innocenti, S.; Ferraro, I.; Nonino, M.; Monelli, M.; Prada Moroni, P. G.; Romaniello, M.; Walker, A. R.; Zoccali, M.

    We performed accurate and deep NIR (J,K) photometry of the Globular Cluster (GC) 47Tuc using data collected with SOFI at New Technology Telescope (NTT) (ESO, La Silla). Data cover a significant fraction of the innermost regions of the cluster and the Color Magnitude Diagram (CMD) ranges from the red HB down to the lower Main Sequence (MS). In the faint magnitude limit, we clearly detected the knee, along the MS, caused by the Collision Induced Absorption. We found that this feature is located at J˜ 18.45 and J-K˜ 0.68 mag.

  6. Using DA White Dwarfs to Calibrate Synthetic Photometry

    NASA Astrophysics Data System (ADS)

    Holberg, J. B.

    2007-04-01

    Four widely used photometric systems, namely the Johnson-Kron-Cousins UBVRI, the Strmgren uvby, the 2MASS JHKs and the Sloan Digital Sky Survey ugriz systems have been directly compared with the HST absolute photometric scale of Bohlin & Gilliland (2004). These comparisons are subsequently used to construct a large grid of accurate synthetic magnitudes for DA white dwarfs. This grid is, in turn, critically evaluated with respect to the observed photometry from substantial samples of actual white dwarfs. The advantages of DA white dwarfs as photometric stars are emphasized, and the prospects for extending the use of these stars into the near infrared are highlighted.

  7. MYRaf: An Easy Aperture Photometry GUI for IRAF

    NASA Astrophysics Data System (ADS)

    Niaei, M. S.; KiliÇ, Y.; Özeren, F. F.

    2015-07-01

    We describe the design and development of MYRaf, a GUI (Graphical User Interface) that aims to be completely open-source under General Public License (GPL). MYRaf is an easy to use, reliable, and a fast IRAF aperture photometry GUI tool for those who are conversant with text-based software and command-line procedures in GNU/Linux OSs. MYRaf uses IRAF, PyRAF, matplotlib, ginga, alipy, and SExtractor with the general-purpose and high-level programming language Python, and uses the Qt framework.

  8. Spectroscopy and photometry for low-mass stars in Praesepe

    NASA Technical Reports Server (NTRS)

    Williams, Scott D.; Stauffer, John R.; Prosser, Charles F.; Herter, Terry

    1994-01-01

    We have obtained spectral types, H alpha equivalent widths, and optical photometry for a small sample of late K and M dwarf candidate members of the Praesepe open cluster. At least for the small sample of stars we have observed, all of the Paesepe members later than M2 have H alpha in emission. The chromospheric activity of the Praesepe satrs is essentially the same as that for Hyades members of the same mass, as expected since the two clusters are thought to be the same age.

  9. Charge coupled device based phase resolved stroboscopic photometry of pulsars

    NASA Astrophysics Data System (ADS)

    Kotar, Jurij; Vidrih, Simon; Čadež, Andrej

    2003-06-01

    A stroboscope designed to observe pulsars in the optical spectrum is presented. The absolute phase of the stroboscope is synchronized to better than 2.5 μs with the known radio ephemerides for a given pulsar. The absolute timing is provided by the Global Positioning System clock. With such a device resolved photometry of pulsars can be performed. We demonstrated the instrument's capabilities with the results of a set of observations of the Crab pulsar, the brightest of the known optical pulsars, with a visual magnitude of 16.5, and a rotational frequency of ~29 Hz.

  10. Optical photometry and spectroscopy of Nova Del 2013

    NASA Astrophysics Data System (ADS)

    Tomov, T.; Ilkiewicz, K.; Swierczynski, E.; Belcheva, M.; Dimitrov, D.

    2013-08-01

    We report optical BV photometry and spectroscopy of Nova Del 2013, carried out between August 14.88 UT and August 15.08 UT. Using a 60 cm Cassegrain telescope at the Nicolaus Copernicus University Observatory (Torun, Poland) we estimated the V brightness of the Nova to be 6.31+/-0.02 mag and 6.18+/-0.03 mag on Aug. 14.94 UT and Aug. 15.02 UT respectively. HD 194113 (F2, V=8.00 mag) was used as a comparison star.

  11. EUVE photometry of SS Cygni: Dwarf nova outbursts and oscillations

    SciTech Connect

    Mauche, C.W.

    1995-05-15

    The authors present EUVE Deep Survey photometry and AAVSO optical measurements of the 1993 August and 1994 June/July outbursts of the dwarf nova SS Cygni. The EUV and optical light curves are used to illustrate the different response of the accretion disk to outbursts which begin at the inner edge and propagate outward, and those which begin at the outer edge and propagate inward. Furthermore, the authors describe the properties of the quasi-coherent 7--9 s sinusoidal oscillations in the EUV flux detected during the rise and plateau stages of these outbursts.

  12. CCD time-resolved photometry of faint cataclysmic variables. III

    NASA Technical Reports Server (NTRS)

    Howell, Steve B.; Szkody, Paula; Kreidl, Tobias J.; Mason, Keith O.; Puchnarewicz, E. M.

    1990-01-01

    CCD time-resolved photometry in V, B, and near-IR for 17 faint cataclysmic variables (CVs) is presented and analyzed. The data are obtained at Kitt Peak National Observatory, the Perkins reflector, Lowell Observatory, and the Observatorio del Roque de los Muchachos from April-June 1989. The degree of variability and periodicities for the CVs are examined. It is observed that the variability of most of the stars is consistent with CV class behavior. Orbital periods for five CVs are determined, and three potential eclipsing systems are detected.

  13. Seasonal dynamics of the land surface energy balance of a boreal forest-peatland landscape affected by degrading permafrost in the Taiga Plains, Canada

    NASA Astrophysics Data System (ADS)

    Helbig, M.; Wischnewski, K.; Chasmer, L.; Quinton, W. L.; Kljun, N.; Detto, M.; Sonnentag, O.

    2014-12-01

    Northern boreal ecosystems along the southern limit of permafrost comprise a mosaic of forests with permafrost, and permafrost-free peatland and lake ecosystems. The proportion of permafrost-free areas has rapidly increased over the last decades due to increasingly warmer air temperatures. This change in land cover causes changes in vegetation composition and structure affecting land surface characteristics such as albedo and surface roughness with important implications for the land surface energy balance and thus regional climate. For example, a decrease in sensible heat flux potentially cools the atmosphere and thus constitutes a negative feedback to the climate system. Changes in latent heat fluxes alter regional water vapour dynamics and thus may affect precipitation patterns. To better understand the land surface energy balance under the influence of degrading permafrost, we measured sensible and latent heat fluxes with two eddy covariance systems, one at 15 m and one at 2 m above the ground surface, along with net radiation and soil heat flux at Scotty Creek, a watershed in the discontinuous permafrost zone in the southern part of the Northwest Territories, Canada. The flux footprint of the 15 m-eddy covariance system covers an area equally covered by black spruce forests and permafrost-free, treeless peatlands whereas the flux footprint of the adjacent 2 m-eddy covariance system covers a single bog within the footprint of the 15 m system. Peak sensible heat fluxes at the bog were up to 200 W m-2 smaller than the landscape-scale fluxes between April and July 2014. During the snow free period, peak latent heat fluxes at the wet bog were about 50 W m-2 higher than the landscape-scale fluxes. Albedo of the forest was generally smaller compared to the bog except for the immediate post-melt period when the bog was affected by widespread surface flooding. This difference in albedo leads to higher net radiation at the forest site, particularly during the snow cover period. Our nested tower measurements indicate that with further permafrost degradation sensible heat and latent heat fluxes are likely to decrease and increase, respectively. This shift in the land surface energy balance could attenuate the regional positive air temperature trend and favour increased summer precipitation in the northern boreal zone.

  14. Hepatitis B immunoprophylaxis failure and the presence of hepatitis B surface gene mutants in the affected children.

    PubMed

    Lee, Le Ye; Aw, Marion; Rauff, Mary; Loh, Kah-Sin; Lim, Seng Gee; Lee, Guan Huei

    2015-08-01

    Hepatitis B virus (HBV) infection is usually vertically transmitted from the mother to child during birth in Asian countries. Despite immunization, immunoprophylaxis failure is well-documented. The aim of the study was to study immunoprophylaxis failure rate in the cohort of infants delivered by chronic HBV-infected mothers and to determine risk factors for failure. This was an observational study involving chronic hepatitis B infected mothers seen at a tertiary care center in Singapore between June 2009 and December 2013. Infants born to these mothers were recruited after they had completed the recommended vaccination schedule. Serological testing for the children was performed 3 months after completion of the last dose of vaccine. HBV surface gene sequencing was carried out if HBV DNA was detectable in the children. Among the 161 mothers enrolled, most were HBeAg negative. HBeAg positive mothers were younger and had a significantly higher viral load (6.5 log) as compared to HBeAg negative mothers (1.35 log) (P < 0.001). Four children (2.6%) were found to have immunoprophylaxis failure. Two occurred in children delivered by mothers with extremely high viral load of more than 5 × 10(7)  IU/ml. HBV surface gene mutations were detected in most children (3 out of 4) with immunoprophylaxis failure. The overall effectiveness of the hepatitis B vaccination program was high. High maternal viral load and presence of surface gene mutants may be potential contributors. PMID:25782362

  15. An Evaluation of the Scale at which Ground-Surface Heat Flux Patchiness Affects the Convective Boundary Layer Using Large-Eddy Simulations.

    NASA Astrophysics Data System (ADS)

    Avissar, Roni; Schmidt, Tatyana

    1998-08-01

    The effects on the convective boundary layer (CBL) of surface heterogeneities produced by surface sensible heat flux waves with different means, amplitudes, and wavelengths were investigated here. The major objective of this study was to evaluate at which scale surface heterogeneity starts to significantly affect the heat fluxes in the CBL. The large-eddy simulation option of the Regional Atmospheric Modeling System developed at Colorado State University was used for that purpose. Avissar et al. evaluated this model against observations and demonstrated its reliability. It appears that the impact of amplitude and wavelength of a heat wave is nonlinearly dependent upon the mean heating rate. The circulations (or rolls) resulting from surface heterogeneity are strong when the amplitude and the wavelength of the heat wave are large, especially at low mean heating rate. In that case the profiles of horizontally averaged variables are quite strongly modified in the CBL. The potential temperature is not constant with elevation, and the sensible heat flux considerably departs from the linear variation with height obtained in a typical CBL that develops over a homogeneous domain. The mean turbulence kinetic energy profile depicts two maxima, one near the ground surface and one near the top of the CBL, corresponding to the strong horizontal flow that develops near the ground surface and the return flow at the top of the CBL. In a dry atmosphere, a weak background wind of 2.5 m s1 is strong enough to considerably reduce the impact of ground-surface heterogeneity on the CBL. A moderate background wind of 5 m s1 virtually eliminates all impacts that could potentially be produced in realistic landscapes. Water vapor does not significantly affect the CBL. However, the formation of rolls at preferential locations within the heterogeneous domain results in `pockets' of high moisture concentration, which have a strong potential for clouds formation. Such clouds may not form over homogeneous domains where moisture is more uniformly distributed, and the CBL is not as high as in heterogeneous domains. From this study, it can be concluded that as long as the `patchiness' of the landscape has a characteristic length scale smaller than about 5-10 km (even without background wind), the `mosaic of tiles' type of land surface scheme suggested by Avissar and Pielke can be applied to represent the land surface in atmospheric models. At larger scales, the impact of landscape heterogeneity may be significant, especially when the atmosphere is humid. Therefore, this study supports previous estimates, which were based on theoretical analyses.

  16. Mutations in Arabidopsis thaliana genes involved in the tryptophan biosynthesis pathway affect root waving on tilted agar surfaces

    NASA Technical Reports Server (NTRS)

    Rutherford, R.; Gallois, P.; Masson, P. H.

    1998-01-01

    Arabidopsis thaliana roots grow in a wavy pattern upon a slanted surface. A novel mutation in the anthranilate synthase alpha 1 (ASA1) gene, named trp5-2wvc1, and mutations in the tryptophan synthase alpha and beta 1 genes (trp3-1 and trp2-1, respectively) confer a compressed root wave phenotype on tilted agar surfaces. When trp5-2wvc1 seedlings are grown on media supplemented with anthranilate metabolites, their roots wave like wild type. Genetic and pharmacological experiments argue that the compressed root wave phenotypes of trp5-2wvc1, trp2-1 and trp3-1 seedlings are not due to reduced IAA biosynthetic potential, but rather to a deficiency in L-tryptophan (L-Trp), or in a L-Trp derivative. Although the roots of 7-day-old seedlings possess higher concentrations of free L-Trp than the shoot as a whole, trp5-2wvc1 mutants show no detectable alteration in L-Trp levels in either tissue type, suggesting that a very localized shortage of L-Trp, or of a L-Trp-derived compound, is responsible for the observed phenotype.

  17. Application of an environmental decision support system to a water quality trading program affected by surface water diversions.

    PubMed

    Obropta, Christopher C; Niazi, Mehran; Kardos, Josef S

    2008-12-01

    Environmental decision support systems (EDSSs) are an emerging tool used to integrate the evaluation of highly complex and interrelated physicochemical, biological, hydrological, social, and economic aspects of environmental problems. An EDSS approach is developed to address hot-spot concerns for a water quality trading program intended to implement the total maximum daily load (TMDL) for phosphorus in the Non-Tidal Passaic River Basin of New Jersey. Twenty-two wastewater treatment plants (WWTPs) spread throughout the watershed are considered the major sources of phosphorus loading to the river system. Periodic surface water diversions to a major reservoir from the confluence of two key tributaries alter the natural hydrology of the watershed and must be considered in the development of a trading framework that ensures protection of water quality. An EDSS is applied that enables the selection of a water quality trading framework that protects the watershed from phosphorus-induced hot spots. The EDSS employs Simon's (1960) three stages of the decision-making process: intelligence, design, and choice. The identification of two potential hot spots and three diversion scenarios enables the delineation of three management areas for buying and selling of phosphorus credits among WWTPs. The result shows that the most conservative option entails consideration of two possible diversion scenarios, and trading between management areas is restricted accordingly. The method described here is believed to be the first application of an EDSS to a water quality trading program that explicitly accounts for surface water diversions. PMID:18592303

  18. Multicolor Photometry of the Merging Galaxy Cluster A2319: Dynamics and Star Formation Properties

    NASA Astrophysics Data System (ADS)

    Yan, Peng-Fei; Yuan, Qi-Rong; Zhang, Li; Zhou, Xu

    2014-05-01

    Asymmetric X-ray emission and a powerful cluster-scale radio halo indicate that A2319 is a merging cluster of galaxies. This paper presents our multicolor photometry for A2319 with 15 optical intermediate filters in the Beijing-Arizona-Taiwan-Connecticut (BATC) system. There are 142 galaxies with known spectroscopic redshifts within the viewing field of 58' × 58' centered on this rich cluster, including 128 member galaxies (called sample I). A large velocity dispersion in the rest frame, 1622^{+91}_{-70} km s-1, suggests merger dynamics in A2319. The contour map of projected density and localized velocity structure confirm the so-called A2319B substructure, at ~10' northwest to the main concentration A2319A. The spectral energy distributions (SEDs) of more than 30,000 sources are obtained in our BATC photometry down to V ~ 20 mag. A u-band (~3551 Å) image with better seeing and spatial resolution, obtained with the Bok 2.3 m telescope at Kitt Peak, is taken to make star-galaxy separation and distinguish the overlapping contamination in the BATC aperture photometry. With color-color diagrams and photometric redshift technique, 233 galaxies brighter than h BATC = 19.0 are newly selected as member candidates after an exclusion of false candidates with contaminated BATC SEDs by eyeball-checking the u-band Bok image. The early-type galaxies are found to follow a tight color-magnitude correlation. Based on sample I and the enlarged sample of member galaxies (called sample II), subcluster A2319B is confirmed. The star formation properties of cluster galaxies are derived with the evolutionary synthesis model, PEGASE, assuming a Salpeter initial mass function and an exponentially decreasing star formation rate (SFR). A strong environmental effect on star formation histories is found in the manner that galaxies in the sparse regions have various star formation histories, while galaxies in the dense regions are found to have shorter SFR time scales, older stellar ages, and higher interstellar medium metallicities. For the merging cluster A2319, local surface density is a better environmental indicator rather than the cluster-centric distance. Compared with the well-relaxed cluster A2589, a higher fraction of star-forming galaxies is found in A2319, indicating that the galaxy-scale turbulence stimulated by the subcluster merger might have played a role in triggering the star formation activity.

  19. Accurate PSF-matched photometry for the J-PAS survey

    NASA Astrophysics Data System (ADS)

    Jimenez-Teja, Yolanda; Benitez, Txitxo; Dupke, Renato a.

    2015-08-01

    The Javalambre-PAU Astrophysical Survey (J-PAS) is expected to map 8,600 squared-degrees of the sky using 54 narrow and 5 broad band filters. Carried out by a Spanish-Brazilian consortium, the main goal of this survey is to measure Baryon Acoustic Oscillations (BAOs) with photometric redshifts. The expectation is measuring these photometric redshifts with a precision of dz/(1 + z) ~ 0.003 for 100 million galaxies and a few millions of quasars, and reaching an accuracy of dz/(1 + z) ~ 0.01 for other 300 million galaxies. With these numbers, it will be possible to determine w in the Dark Energy (DE) equation of state with an accuracy of < 4%. To achieve such precision and measure the radial BAOs, not only an advanced technical setup but also special data processing tools are required. These tools must be accurate as well as suitable to be implemented in fully automated and computationally efficient algorithms.The factor that most influences the photometric redshift precision is the quality of the photometry. For that reason we have developed a new technique based on the Chebyshev-Fourier bases (CHEFs, Jiménez-Teja & Benítez 2012, ApJ, 745, 150) to obtain a highly precise multicolor photometry without PSF consideration, thus saving a considerable amount of time and circumventing severe problems such as the PSF variability across the images. The CHEFs are a set of mathematical orthonormal bases with different scale and resolution levels, originally designed to fit the surface light distribution of galaxies. They have proved to be able to model any kind of morphology, including spirals, highly elliptical, or irregular galaxies, including isophotal twists and fine substructure. They also fit high signal-to-noise images, lensing arcs and stars with great accuracy. We can calculate optimal, unbiased, total magnitudes directly through these CHEFs models and, thus, colors without needing the PSF.We compare our photometry with widely-used codes such as SExtractor (Bertin & Arnouts 1996, Astron Astrophys Sup, 117, 393) and ColorPro (Coe et al. 2006, AJ, 132, 926), using real data from the COSMOS survey, the HUDF, and the XDF.

  20. Multicolor photometry of the merging galaxy cluster A2319: Dynamics and star formation properties

    SciTech Connect

    Yan, Peng-Fei; Yuan, Qi-Rong; Zhang, Li; Zhou, Xu E-mail: yuanqirong@njnu.edu.cn

    2014-05-01

    Asymmetric X-ray emission and a powerful cluster-scale radio halo indicate that A2319 is a merging cluster of galaxies. This paper presents our multicolor photometry for A2319 with 15 optical intermediate filters in the Beijing-Arizona-Taiwan-Connecticut (BATC) system. There are 142 galaxies with known spectroscopic redshifts within the viewing field of 58' × 58' centered on this rich cluster, including 128 member galaxies (called sample I). A large velocity dispersion in the rest frame, 1622{sub −70}{sup +91} km s{sup –1}, suggests merger dynamics in A2319. The contour map of projected density and localized velocity structure confirm the so-called A2319B substructure, at ∼10' northwest to the main concentration A2319A. The spectral energy distributions (SEDs) of more than 30,000 sources are obtained in our BATC photometry down to V ∼ 20 mag. A u-band (∼3551 Å) image with better seeing and spatial resolution, obtained with the Bok 2.3 m telescope at Kitt Peak, is taken to make star-galaxy separation and distinguish the overlapping contamination in the BATC aperture photometry. With color-color diagrams and photometric redshift technique, 233 galaxies brighter than h {sub BATC} = 19.0 are newly selected as member candidates after an exclusion of false candidates with contaminated BATC SEDs by eyeball-checking the u-band Bok image. The early-type galaxies are found to follow a tight color-magnitude correlation. Based on sample I and the enlarged sample of member galaxies (called sample II), subcluster A2319B is confirmed. The star formation properties of cluster galaxies are derived with the evolutionary synthesis model, PEGASE, assuming a Salpeter initial mass function and an exponentially decreasing star formation rate (SFR). A strong environmental effect on star formation histories is found in the manner that galaxies in the sparse regions have various star formation histories, while galaxies in the dense regions are found to have shorter SFR time scales, older stellar ages, and higher interstellar medium metallicities. For the merging cluster A2319, local surface density is a better environmental indicator rather than the cluster-centric distance. Compared with the well-relaxed cluster A2589, a higher fraction of star-forming galaxies is found in A2319, indicating that the galaxy-scale turbulence stimulated by the subcluster merger might have played a role in triggering the star formation activity.

  1. Apatite formation on bioactive calcium-silicate cements for dentistry affects surface topography and human marrow stromal cells proliferation.

    PubMed

    Gandolfi, Maria Giovanna; Ciapetti, Gabriela; Taddei, Paola; Perut, Francesca; Tinti, Anna; Cardoso, Marcio Vivan; Van Meerbeek, Bart; Prati, Carlo

    2010-10-01

    The effect of ageing in phosphate-containing solution of bioactive calcium-silicate cements on the chemistry, morphology and topography of the surface, as well as on in vitro human marrow stromal cells viability and proliferation was investigated. A calcium-silicate cement (wTC) mainly based on dicalcium-silicate and tricalcium-silicate was prepared. Alpha-TCP was added to wTC to obtain wTC-TCP. Bismuth oxide was inserted in wTC to prepare a radiopaque cement (wTC-Bi). A commercial calcium-silicate cement (ProRoot MTA) was tested as control. Cement disks were aged in DPBS for 5 h ('fresh samples'), 14 and 28 days, and analyzed by ESEM/EDX, SEM/EDX, ATR-FTIR, micro-Raman techniques and scanning white-light interferometry. Proliferation, LDH release, ALP activity and collagen production of human marrow stromal cells (MSC) seeded for 1-28 days on the cements were evaluated. Fresh samples exposed a surface mainly composed of calcium-silicate hydrates CSH (from the hydration of belite and alite), calcium hydroxide, calcium carbonate, and ettringite. Apatite nano-spherulites rapidly precipitated on cement surfaces within 5 h. On wTC-TCP the Ca-P deposits appeared thicker than on the other cements. Aged cements showed an irregular porous calcium-phosphate (Ca-P) coating, formed by aggregated apatite spherulites with interspersed calcite crystals. All the experimental cements exerted no acute toxicity in the cell assay system and allowed cell growth. Using biochemical results, the scores were: fresh cements>aged cements for cell proliferation and ALP activity (except for wTC-Bi), whereas fresh cements

  2. Estimating environmental conditions affecting protozoal pathogen removal in surface water wetland systems using a multi-scale, model-based approach.

    PubMed

    Daniels, Miles E; Hogan, Jennifer; Smith, Woutrina A; Oates, Stori C; Miller, Melissa A; Hardin, Dane; Shapiro, Karen; Los Huertos, Marc; Conrad, Patricia A; Dominik, Clare; Watson, Fred G R

    2014-09-15

    Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii are waterborne protozoal pathogens distributed worldwide and empirical evidence suggests that wetlands reduce the concentrations of these pathogens under certain environmental conditions. The goal of this study was to evaluate how protozoal removal in surface water is affected by the water temperature, turbidity, salinity, and vegetation cover of wetlands in the Monterey Bay region of California. To examine how protozoal removal was affected by these environmental factors, we conducted observational experiments at three primary spatial scales: settling columns, recirculating wetland mesocosm tanks, and an experimental research wetland (Molera Wetland). Simultaneously, we developed a protozoal transport model for surface water to simulate the settling columns, the mesocosm tanks, and the Molera Wetland. With a high degree of uncertainty expected in the model predictions and field observations, we developed the model within a Bayesian statistical framework. We found protozoal removal increased when water flowed through vegetation, and with higher levels of turbidity, salinity, and temperature. Protozoal removal in surface water was maximized (~0.1 hour(-1)) when flowing through emergent vegetation at 2% cover, and with a vegetation contact time of ~30 minutes compared to the effects of temperature, salinity, and turbidity. Our studies revealed that an increase in vegetated wetland area, with water moving through vegetation, would likely improve regional water quality through the reduction of fecal protozoal pathogen loads. PMID:25016109

  3. Network-scale dynamics of sediment mixtures: how do tectonics affect surface bed texture and channel slope?

    NASA Astrophysics Data System (ADS)

    Gasparini, N. M.; Bras, R. L.; Tucker, G. E.

    2003-04-01

    An alluvial channel's slope and bed texture are intimately linked. Along with fluvial discharge, these variables are the key players in setting alluvial transport rates. We know that both channel slope and mean grain size usually decrease downstream, but how sensitive are these variables to tectonic changes? Are basin concavity and downstream fining drastically disrupted during transitions from one tectonic regime to another? We explore these questions using the CHILD numerical landscape evolution model to generate alluvial networks composed of a sand and gravel mixture. The steady-state and transient patterns of both channel slope and sediment texture are investigated. The steady-state patterns in slope and sediment texture are verified independently by solving the erosion equations under equilibrium conditions, i.e. the case when the erosion rate is equal to the uplift rate across the entire landscape. The inclusion of surface texture as a free parameter (as opposed to just channel slope) leads to some surprising results. In all cases, an increase in uplift rate results in channel beds which are finer at equilibrium (for a given drainage area). Higher uplift rates imply larger equilibrium transport rates; this leads to finer channels that have a smaller critical shear stress to entrain material, and therefore more material can be transported for a given discharge (and channel slope). Changes in equilibrium slopes are less intuitive. An increase in uplift rates can cause channel slopes to increase, remain the same, or decrease, depending on model parameter values. In the surprising case in which equilibrium channel slopes decrease with increasing uplift rates, we suggest that surface texture changes more than compensate for the required increase in transport rates, causing channel slopes to decrease. These results highlight the important role of sediment grain size in determining transport rates and caution us against ignoring this important variable in fluvial networks.

  4. Performance of loblolly, Virginia, and shortleaf pine on a reclaimed surface mine as affected by Pisolithus tinctorius ectomycorrhizae and fertilization

    SciTech Connect

    Walker, R.F.; West, D.C.; McLaughlin, S.B.; Amundsen, C.C.

    1985-01-01

    The effects of an induced Pisolithus tinctorius infection and broadcast fertilization were studied on the survival and growth of loblolly (Pinus taeda), Virginia (Pinus virginiana), and shortleaf (Pinus echinata) pine outplanted on a reclaimed east Tennessee coal surface mine site. The study site had been previously regraded and hydroseeded with a mixture of ground cover species. After six years, the survival and growth of loblolly pine with P. tinctorius ectomycorrhizae were signficantly improved in comparison with control loblolly pine infected by other ectomycorrhizal symbionts. The response of the Virginia pine to the infection by P. tinctorius was negligible after five years. Fertilization at outplanting significantly reduced the survival of both loblolly and Virginia pine. Fertilization of the shortleaf pine at the start of the third growing season did not result in the drastic mortality exhibited by the loblolly pine, and to a lesser extent the Virginia pine, in response to fertilization at outplanting, but this treatment was still detrimental to the survival of the shortleaf pine after five years. There was a marginal improvement in the survival and growth of the shortleaf pine in response to the infection by P. tinctorius. The effect of fertilization on the growth of all three species was negligible, and the increase in mortality associated with this treatment appeared to be primarily the result of increased competition with the ground cover species. These results indicate that the magnitude of the response exhibited by pines on harsh sites to an ectomycorrhizal infection by P. tinctorius is species dependent. Also, broadcast fertilization is inefficient on surface-mined sites where a vegetative ground cover has been established. 11 refs., 3 tabs.

  5. Spectroscopy and photometry campaign on three bright Wolf Rayet stars

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2013-06-01

    Dr. Noel Richardson (Universite de Montreal) and colleagues have invited AAVSO observers to participate in an international professional-amateur spectroscopy and photometry campaign on the Wof Rayet stars WR 134, WR 135, and WR 137 (HD 191765, HD 192103, and HD 192641). The campaign has begun and runs through September 17, 2013. The purpose of the campaign is to study clumping aspects of the strong winds and changes present in large structures in the stellar winds in these WR stars. Spectroscopy and UBVRI time-series observations are requested. Supplemental targets to be observed if time permits are V905 Sco (HD 160529) and V4375 Sgr (HD 316285). Finder charts with sequences may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Photometry should be submitted to the AAVSO International Database. Details of the campaign are given at: http://www.stsci.de/wr134/index.htm. Instructions for sending spectroscopy data to Dr. Richardson are given at http! ://www.stsci.de/wr134/pdf/data_transfer.pdf.

  6. High Precision Photometry for the K2 Mission

    NASA Astrophysics Data System (ADS)

    Huang, Xu; Soares-Furtado, Melinda; Penev, Kaloyan; Hartman, Joel; Bakos, Gaspar; Bhatti, Waqas; Domsa, Istvan; de Val-Borro, Miguel

    2015-12-01

    The two reaction wheel K2 mission brings new challenges for the data reduction processes. We developed a reduction pipeline for extracting high precision photometry from the K2 dataset and we use this pipeline to generate light curves for the K2 Campaign 0 super-stamps and K2 Campaign 1 target pixel dataset. Key to our reduction technique is the derivation of global astrometric solutions from the target stamps from which accurate centroids are passed on for high precision photometry extraction. We also implemented the image subtraction method to reduce the K2 Campaign 0 super-stamps containing open clusters M35 and NGC2158. We extract target light curvesfor sources from a combined UCAC4 and EPIC catalogue -- this includes not only primary targets of the K2 Mission, but also other stars that happen to fall on the pixel stamps. Our astrometric solutions achieve a median residual of ~0.127". For bright stars, our best 6.5 hour precision for raw light curves is ~20 parts per million (ppm). For our detrended light curves, the best 6.5 hour precision achieved is ~15 ppm. We show that our detrended light curves have fewer systematic effects (or trends, or red-noise) than light curves produced by other groups from the same observations. We highlight the measurements of rotation curves using the K2 light curves of stars within open cluster M35 and NGC2158.

  7. Orion Project: A Photometry and Spectroscopy Project for Small Observatories

    NASA Astrophysics Data System (ADS)

    Hopkins, Jeffrey L.

    2014-05-01

    Orion, the hunter, is one of the most famous constellations. Its declination is such that it is visible from most of the civilized world. In addition, most of the stars of Orion are very bright and interesting. Originally this Project was called the Betelgeuse Campaign, but four more stars were added so the name was changed to the Orion Project. The Project now includes Betelgeuse, Rigel and the three stars of Orion's belt, Mintaka, Alnilam and Alnitak. Both photometry and spectroscopy provide data for the Project. The Project has several goals. First is to help beginners with photometry and spectroscopy. The second goal is the actual observations and data. Because these stars are very bright, they are seldom observed in detail. Their brightness also posses a problem for most professional observatories. It is hoped that by having observations over a long time, interesting changes can be seen that will warrant closer investigation. The AAVSO has an excellent archive of photometric data, but is still lacking a means of handling spectroscopic data. As a third goal it is hoped that the procedures refined in this Project for spectroscopic data may help promote a similar system for the AAVSO.

  8. A new look at photometry of the Moon

    USGS Publications Warehouse

    Goguen, J.D.; Stone, T.C.; Kieffer, H.H.; Buratti, B.J.

    2010-01-01

    We use ROLO photometry (Kieffer, H.H., Stone, T.C. [2005]. Astron. J. 129, 2887-2901) to characterize the before and after full Moon radiance variation for a typical highlands site and a typical mare site. Focusing on the phase angle range 45??. ) to calculate the scattering matrix and solve the radiative transfer equation for I/. F. The mean single scattering albedo is ??=0.808, the asymmetry parameter is ???cos. ?????=0.77 and the phase function is very strongly peaked in both the forward and backward scattering directions. The fit to the observations for the highland site is excellent and multiply scattered photons contribute 80% of I/. F. We conclude that either model, roughness or multiple scattering, can match the observations, but that the strongly anisotropic phase functions of realistic particles require rigorous calculation of many orders of scattering or spurious photometric roughness estimates are guaranteed. Our multiple scattering calculation is the first to combine: (1) a regolith model matched to the measured particle size distribution and index of refraction of the lunar soil, (2) a rigorous calculation of the particle phase function and solution of the radiative transfer equation, and (3) application to lunar photometry with absolute radiance calibration. ?? 2010 Elsevier Inc.

  9. The MOST Asteroseismology Mission: Ultraprecise Photometry from Space

    NASA Astrophysics Data System (ADS)

    Walker, Gordon; Matthews, Jaymie; Kuschnig, Rainer; Johnson, Ron; Rucinski, Slavek; Pazder, John; Burley, Gregory; Walker, Andrew; Skaret, Kristina; Zee, Robert; Grocott, Simon; Carroll, Kieran; Sinclair, Peter; Sturgeon, Don; Harron, John

    2003-09-01

    The Microvariablity and Oscillations of Stars (MOST) mission is a low-cost microsatellite designed to detect low-degree acoustic oscillations (periods of minutes) with micromagnitude precision in solar-type stars and metal-poor subdwarfs. There are also plans to detect light reflected from giant, short-period, extrasolar planets and the oscillations of roAp stars and the turbulent variability in the dense winds of Wolf-Rayet stars. This paper describes the experiment and how we met the challenge of ultraprecise photometry despite severe constraints on the mass, volume, and power available for the instrument. A side-viewing, 150 mm aperture Rumak-Maksutov telescope feeds two frame-transfer CCDs, one for tracking and the other for science. There is a single 300 nm wide filter centered at 525 nm. Microlenses project Fabry images of the brighter (V<=10) target stars onto the science CCD. Fainter target stars will be focused directly elsewhere on the CCD. MOST was launched on 2003 June 30 into a low-Earth, Sun-synchronous, polar orbit allowing stars between -19° and +36° declination to be viewed continuously for up to 60 days. Attitude is controlled by reaction wheels and magnetotorquers. A solar safety shutter over the telescope diagonal is the only other moving part. Accumulated photometry will be used to calibrate response across the target field stop, and data will be compressed and downloaded to three dedicated ground stations.

  10. UBV Photometry of the young open cluster Berkely 87

    NASA Astrophysics Data System (ADS)

    Akinyemi, Abolaji; Eskridge, Paul B.

    2015-01-01

    We obtained UBV imaging of a field in the young open cluster Berkeley 87. From these images, we measured the brightness of ~180 stars in the cluster. Our photometry was calibrated using published photometry (Turner & Forbes 1982 PASP 94, 789) of a subset of stars in our field. The cluster is in a region of the sky with strongly varying extinction. Therefore we made a (U-B)-(B-V) color-color diagram of the field and used this to de-redden the stars on a case by case basis. We de-reddened the stars using the unreddened supergiant and main sequence colors from Astrophysical Quantities (Cox 2000).The color-magnitude diagrams of the de-reddened stars are compared to the Padova isochrones(Marigo et al 2008 A&A 482 883). The isochrones are generated for a range of ages, with solar metalicity and no α enhancement. The best fit for the isochrones was the main sequence de-reddened stars from which the age of the cluster is estimated to be 20 million years. This is older than previous age estimates (1-5 million years) from earlier studies of the cluster. This may indicate age variation in the cluster.We acknowledge the support of the Physics and Astronomy department, and the College of Science and Engineering, Minnesota State University, Mankato.

  11. Multicolor photometry of triple system b Per requested

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2013-01-01

    Dr. Bob Zavala (U.S. Naval Observatory, Flagstaff) has requested AAVSO assistance in obtaining multicolor photometry of the bright triple system b Per in order to prepare for and detect a possible eclipse of the AB components by the C component predicted for 2013 January 23. Multi-color photometric observations of 4.5V b Per are requested 2013 January 23 through February 04. Based on a revised period of 702.45 ± 0.05 days, the next time of minimum light is predicted for HJD = 2456321.35 ± 0.05 (UT 2013 January 28 20:24UT ± 1.5 hours). The eclipse may last for up to four days, so the coverage requested will provide both a baseline out-of-eclipse light curve and a multi-color eclipse light curve for analysis. Photometry is needed at the level of 0.02-0.03 magnitude or better, as the eclipse may be as deep as 0.1 magnitude. For PEP observers, V coverage, and B if possible, is requested. DSLR observers should use whatever band(s) are available to them. Finder charts may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and links.

  12. Ca by Photometry of Southern Globular Clusters: Now or Never

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Woo; Walker, Alistair

    2011-08-01

    Our recent study of Galactic globular clusters using Ca by photometry has shown that many globular clusters have multiple red giant branch populations with distinct calcium abundances. This suggests that these globular clusters, like ω Cen, are most likely the relics of more massive primeval dwarf galaxies that merged and disrupted to form the proto-Galaxy. We seek to obtain high precision Ca by photometry for 9 southern globular clusters with signatures of multiple stellar populations and 2 dwarf satellite galaxies using the CTIO- 4m/Mosaic II and our own Ca by filters. Our proposed observations will provide unique opportunity to explore fundamental aspects of stellar evolution, the star formation and chemical enrichment histories of globular clusters and dwarf satellite galaxies, and furthermore, the formation of the Milky Way Galaxy in the (Lambda)CDM hierarchical merging paradigm. Since the Mosaic II imager will be retired in mid- 2011B, it will be our last chance to provide invaluable data to the community for southern globular clusters.

  13. PHOTOMETRY OF VARIABLE STARS FROM DOME A, ANTARCTICA

    SciTech Connect

    Wang Lingzhi; Macri, Lucas M.; Krisciunas, Kevin; Wang Lifan; Ashley, Michael C. B.; Lawrence, Jon S.; Luong-Van, Daniel; Storey, John W. V.; Cui Xiangqun; Gong Xuefei; Yuan Xiangyan; Feng Longlong; Yang Ji; Zhu Zhenxi; Liu Qiang; Zhou Xu; Pennypacker, Carl R.; Shang Zhaohui; Yang Huigen; York, Donald G.

    2011-11-15

    Dome A on the Antarctic plateau is likely one of the best observing sites on Earth thanks to the excellent atmospheric conditions present at the site during the long polar winter night. We present high-cadence time-series aperture photometry of 10,000 stars with i < 14.5 mag located in a 23 deg{sup 2} region centered on the south celestial pole. The photometry was obtained with one of the CSTAR telescopes during 128 days of the 2008 Antarctic winter. We used this photometric data set to derive site statistics for Dome A and to search for variable stars. Thanks to the nearly uninterrupted synoptic coverage, we found six times as many variables as previous surveys with similar magnitude limits. We detected 157 variable stars, of which 55% were unclassified, 27% were likely binaries, and 17% were likely pulsating stars. The latter category includes {delta} Scuti, {gamma} Doradus, and RR Lyrae variables. One variable may be a transiting exoplanet.

  14. Near-IR Spectroscopy and Visual Broadband Photometry of Unbound Asteroid Pairs

    NASA Astrophysics Data System (ADS)

    Wolters, Stephen D.; Weissman, P.; Duddy, S. R.; Christou, A.; Green, S. F.; Lowry, S. C.; Rozitis, B.

    2012-10-01

    Over 62 pairs of asteroids have been identified with extremely similar orbits (Rozek, Breiter, and Jopek 2011, MNRAS 412, 987). Backwards integration of their orbits show that each pair probably experienced a very low-velocity close encounter, in many cases less than 1 Myr ago (e.g. Vokrouhlický and Nesvorný 2008, AJ 136, 280). Pravec et al. (2010, Nature, 466, 1085) examined 35 pairs and found that the secondary/primary mass ratio is <0.2. Also, as this ratio approaches 0.2, the rotation period of the primary increases. This is consistent with formation of the pairs through rotational fission of a parent rubble-pile asteroid (Scheeres 2007, Icarus 189, 370). However, the pairs were linked through dynamical considerations alone, and mass ratios were determined using catalogued visual magnitudes and the assumption that the albedos and bulk densities of the components are identical. We are undertaking a campaign of characterising the asteroids in these pairs using visual and NIR spectroscopy as well as thermal IR photometry. We present 0.8-2.5 micron spectroscopic observations of using SpeX on NASA-IRTF, and BVRI photometry using the 0.6-m Table Mountain Observatory telescope. Our goals are to assess the similarity of the spectra of the components’ surfaces (e.g. Duddy et al. 2012, A&A, 539, A36) and also to look for evidence of color variation as a function of rotational phase. Since dynamical studies have placed constraints on the formation ages, if the asteroids are completely resurfaced during formation, we can start to explore the timescales involved in space weathering. We report recent progress in our investigations. This work was supported in part by the NASA Planetary Astronomy Program and done in part at the Jet Propulsion Laboratory under contract with NASA.

  15. Cell surface protein C23 affects EGF-EGFR induced activation of ERK and PI3K-AKT pathways.

    PubMed

    Lv, Shunzeng; Dai, Congxin; Liu, Yuting; Sun, Bowen; Shi, Ranran; Han, Mingzhi; Bian, Ruixiang; Wang, Renzhi

    2015-02-01

    The epidermal growth factor (EGF) pathway has been reported as canonical causes in cancer development. Meanwhile, the involvement of C23 in multiple signaling pathways has been also investigated (Lv et al., 2014). However, the effect of C23 on EGF pathway in glioblastoma is not fully characterized. In the present study, C23 and the epidermal growth factor receptor (EGFR) of U251 cell line were inhibited by C23 and EGFR antibodies, respectively; and then C23 and EGFR siRNAs were used to knock down endogenous C23 and EGFR, respectively. In addition, soft-agar and MTT assay were also introduced. Compared with control, either C23 or EGFR antibodies efficiently repressed the phosphorylation levels of ERK1/2 (p<0.000) and AKT (p<0.000). Similarly, either C23 or EGFR siRNAs indeed resulted in C23 and EGFR knockdown, and further suppressed the expression of p-ERK1/2 and p-AKT. Most importantly, immunoprecipitation revealed C23 interacted with EGFR once U251 was exposed to EGF treatment. In addition, the MTT and soft-agar assay also identified that C23 or EGFR siRNAs could obviously affected cell growth (p=0.004) and invasiveness, as cell viability and colony formation decreased markedly. Our results suggest that C23 plays a crucial role in activation of EGF-induced ERK and PI3K-AKT pathways via interacting with EGFR; furthermore, C23 could be indicative of an important factor in glioblastoma development and a useful target for glioblastoma treatment. PMID:25015231

  16. Affects and Affect Consciousness

    PubMed Central

    MONSEN, JON T.; EILERTSEN, DAG ERIK; MELGÅRD, TROND; ØDEGÅRD, PÅL

    1996-01-01

    Affect consciousness (AC) was operationalized as degrees of awareness, tolerance, nonverbal expression, and conceptual expression of nine specific affects. A semistructured interview (ACI) and separate scales were developed to assess these aspects of affect integration. Their psychometric properties were preliminarily explored by having 20 former psychiatric outpatients complete the interview. Concurrent validity was assessed by using DSM-III-R Axis I and II diagnoses, the Health-Sickness Rating Scale, SCL-90-R, and several indexes from the Minnesota Multiphasic Personality Inventory. Satisfactory interrater reliability and high levels of internal consistency supported the construct validity of the measure. Results suggest the most meaningful use of this instrument is in measuring specific affect and overall AC. Clinically, the ACI has provided highly specific and relevant qualitative data for use in planning psychotherapeutic interventions. PMID:22700292

  17. VizieR Online Data Catalog: Metallicity calibrations for UBV photometry (Karatas+, 2006)

    NASA Astrophysics Data System (ADS)

    Karatas, Y.; Schuster, W. J.

    2007-05-01

    UBV photometry [V, (B-V), (U-B)] has been collected from large data bases in conjunction with the derivation of intrinsic-colour, metallicity and absolute magnitude calibrations of F-, G- and early-K-type stars for uvby-beta photometry being derived by Karata & Schuster (in preparation). (2 data files).

  18. VizieR Online Data Catalog: [Fe/H] & VMAG calibrations for UBV photometry (Karatas+, 2006)

    NASA Astrophysics Data System (ADS)

    Karatas, Y.; Schuster, W. J.

    2007-05-01

    UBV photometry [V, (B-V), (U-B)] has been collected from large data bases in conjunction with the derivation of intrinsic-colour, metallicity and absolute magnitude calibrations of F-, G- and early-K-type stars for uvby-beta photometry being derived by Karata & Schuster (in preparation). (2 data files).

  19. Photoelectric UBV photometry of northern stars from the HK objective-prism survey

    NASA Astrophysics Data System (ADS)

    Doinidis, Steve P.; Beers, Timothy C.

    1990-12-01

    Photoelectric photometry is presented for a sample of 139 halo stars drawn from an extension of the HK objective-prism survey of Beers, Preston, and Shectman to the northern galactic hemisphere. The candidates for which photometry is reported were selected to span a wide range of types, but are dominated by stars classified as type AB, A, or 'metal poor'.

  20. Snow cover and ground surface temperature on a talus slope affected by mass movements. Veleta cirque, Sierra Nevada, Spain

    NASA Astrophysics Data System (ADS)

    Tanarro, L. M.; Palacios, D.; Gómez-Ortiz, A.; Salvador-Franch, F.

    2012-04-01

    This paper analyses the thermal ground behaviour on an alpine talus slope located at the foot of the north wall of the glacial cirque on the Pico del Veleta (3398 m, 37°03'21''N, 3°21'57''W, MAAT: -0,4°C) in Sierra Nevada, SE Spain. There are frequent mass movements on this talus slope, particularly in its central section, caused by the abundant presence of fine-grained sediment and by the water from snowmelt and/or ice degradation in the ground or permafrost (Gómez et al., 2003). To determine the snowmelt pattern and ocurrence of permafrost, a continuous ground surface temperature was kept by installing 6 mini-loggers (HOBO Pendant) along the descending profile of the central talus, which is 170 m long with altitudes ranging from 3180 m at the higher end to 3085 m at the lower end. A thermal borehole was also installed at a depth of 2 m at the base of the slope on an active rock glacier. The results obtained for the period October 2008 - September 2009 show that, in contrast to alpine talus slopes (Luetschg et. al., 2004; Lambiel and Pieracci, 2008), the upper part of the slope is characterized by mean annual ground surface temperatures (MAGST) lower than at the base of the talus, possibly due to the effect of the shadow of the cirque wall. The MAGST oscillate between 0.592°C at the station near the slope apex (S2) and 1.836°C at the station near the base (S5). In winter-spring, when the talus slope is covered with snow, the GST are stabilized at all stations between mid-October and early November. The minimum GST, which express the BTS conditions, oscillate between 0.232 and 0.01°C, depending on the month, with lowest values recorded during the month of April. Only one station (S3, mid-slope) recorded negative values (max. value : - 0.549°C in December and - 0.211 in April ). In summer, the snow disappears fairly quickly between mid- and late July on the intermediate stretch of the talus slope (S3, S4, S6), where the majority of the flows detected occur. In the mid-upper part (S5, S2) the thaw occurs in mid-August. The GST data provide evidence of the current absence of permafrost along the talus slope profile, although some years ago it was detected using BTS methods (Gómez et al., 2003. Gómez-Ortiz, A., Palacios, D., Luengo, E., Tanarro, L. M.; Schulte, L. and Ramos, M., 2003. Talus instability in a recent deglaciation area and its relationship to buried ice and snow cover evolution (Picacho del Veleta, Sierra Nevada, Spain). Geografisca Annaler 85 A (2), 165-182. Lambiel, C. and Pieracci, K. 2008. Permafrost distribution in talus slopes located within the alpine periglacial belt, Swiss Alps. Permafrost and Periglac. Process. 19: 293-304 Luetschg, M.; Stoeckli, M.; Lehning, M.; Haeberli, W., and Ammann, W. 2004. Temperatures in two boreholes at Flüela Pass, Eastern Swiss Alps: the effect of snow redistribution on permafrost distribution patterns in high mountain areas. Permafrost and Periglac. Process. 15: 283-297. Research funded by CGL2009-7343 project, Government of Spain.

  1. Distribution and factors affecting adsorption of sterols in the surface sediments of Bosten Lake and Manas Lake, Xinjiang.

    PubMed

    Liu, Jiang; Yao, Xiaorui; Lu, Jianjiang; Qiao, Xiuwen; Liu, Zilong; Li, Shanman

    2016-03-01

    This study investigated the concentrations and distribution of eight sterol compounds in the surface sediments of Bosten Lake and Manas Lake, Xinjiang, China. The ratios of sterols as diagnostic indices were used to identify pollution sources. The sediment of the two lakes was selected as an adsorbent to investigate the adsorption behaviour of sterols. Results showed that the sterols were widely distributed in the sediments of the lakes in the study areas. The total concentrations of the detected sterols in Bosten Lake and in Manas Lake were 1.584-27.897 and 2.048-18.373 μg g(-1)∙dw, respectively. In all of the sampling sites, the amount of faecal sterols was less than that of plant sterols. β-sitosterol was the dominant plant sterol with a mean concentration of 2.378 ± 2.234 μg g(-1)∙dw; cholesterol was the most abundant faecal sterol with a mean concentration of 1.060 ± 1.402 μg g(-1)∙dw. The pollution level was higher in Bosten Lake than in Manas Lake. Majority of the ratios clearly demonstrated that the contamination by human faecal sources was occurring at stations which are adjacent to residential areas and water inlets. The adsorption behaviour of sterols to sediment suggested that the sterol adsorption coefficients were reduced as temperature increased. As salinity increased, the adsorption quantity also increased. As pH increased, the sediment adsorption of sterol slightly increased because the strong alkaline solution is not conducive to the adsorption of sterols. The ratios between sterols did not change largely with the change in external factors. PMID:26593726

  2. Face shape of unaffected parents with cleft affected offspring: combining three-dimensional surface imaging and geometric morphometrics

    PubMed Central

    Weinberg, SM; Naidoo, SD; Bardi, KM; Brandon, CA; Neiswanger, K; Resick, JM; Martin, RA; Marazita, ML

    2009-01-01

    Objective Various lines of evidence suggest that face shape may be a predisposing factor for nonsyndromic cleft lip with or without cleft palate (CL/P). In the present study, 3D surface imaging and statistical shape analysis were used to evaluate face shape differences between the unaffected (non-cleft) parents of individuals with CL/P and unrelated controls. Methods Sixteen facial landmarks were collected from 3D captures of 80 unaffected parents and 80 matched controls. Prior to analysis, each unaffected parent was assigned to a subgroup on the basis of prior family history (positive or negative). A geometric morphometric approach was utilized to scale and superimpose the landmark coordinate data (Procrustes analysis), test for omnibus group differences in face shape, and uncover specific modes of shape variation capable of discriminating unaffected parents from controls. Results Significant disparity in face shape was observed between unaffected parents and controls (p < 0.01). Notably, these changes were specific to parents with a positive family history of CL/P. Shape changes associated with CL/P predisposition included marked flattening of the facial profile (midface retrusion), reduced upper facial height, increased lower facial height and excess interorbital width. Additionally, a sex-specific pattern of parent-control difference was evident in the transverse dimensions of the nasolabial complex. Conclusions The faces of unaffected parents from multiplex cleft families display meaningful shape differences compared with the general population. Quantitative assessment of the facial phenotype in cleft families may enhance efforts to discover the root causes of CL/P. PMID:19840279

  3. Mutagenesis of two surface-exposed loops of the Bacillus thuringiensis CryIC delta-endotoxin affects insecticidal specificity.

    PubMed Central

    Smith, G P; Ellar, D J

    1994-01-01

    Site-directed mutagenesis was used to determine the role of two surface-exposed loops (Gly-317-Phe-320 and Gln-374-Pro-377) in the insecticidal specificity of the Bacillus thuringiensis CryIC delta-endotoxin. Mutant toxins were generated by PCR using degenerate oligonucleotide primers, and expressed in Escherichia coli. More than 50 mutant toxins were screened for toxicity to the lepidopteran Spodoptera frugiperda Sf9 cell line using an in vitro lawn assay. A panel of these mutant toxins, which included toxic and non-toxic variants from both loops, was further screened for activity towards Aedes aegypti larvae. The activity of these mutants to Sf9 cells was quantified more precisely using a cell lysis assay. Three categories of mutants were identified: (1) those non-toxic to either Sf9 cells or Aedes aegypti larvae; (2) those fully toxic to both genera; and (3) those which were only toxic to Sf9 cells. For the first loop, the differential specificity was not restricted to any single residue. In the second loop, two mutant toxins with a Pro-377-->Ala substitution displayed this phenotype. The time dependence of toxicity towards Sf9 cells was examined using the same panel of mutants. All toxic mutants displayed an identical time course to the wild-type toxin, with the exception of the two Pro-377-->Ala mutants of the second loop. These toxins displayed a lower time dependence, no cell death occurring within the first hour of incubation. These results show that the two loops are important determinants of both the activity and specificity of the CryIC delta-endotoxin. Images Figure 1 PMID:8093015

  4. DOE-EMSP Final Report: Characterization of Changes in Colloid and DNAPL Affecting Surface Chemistry and Remediation

    SciTech Connect

    Susan E. Powers; Stefan J. Grimberg; Miles Denham

    2007-02-07

    The waste disposal to the M-area basin and A-14 outfall at the Savannah River Department of Energy facility in Aiken SC (USA) included a wide variety of inorganic aqueous flows and organic solvents in the form of dense non-aqueous phase liquids (DNAPL). The DNAPL has migrated through the subsurface resulting in widespread groundwater contamination. The goal of this research was to identify and quantify processes that could have affected the migration and remediation of the DNAPL in the subsurface. It was hypothesized that the variety of waste disposed at this site could have altered the mineral, microbial and DNAPL properties at this site relative to other DNAPL sites. The DNAPL was determined to have a very low interfacial tension and is suspected to be distributed in fine grained media, thereby reducing the effectiveness of soil vapor extraction remediation efforts. Although the DNAPL is primarily comprised of tetrachloroethene and trichloroethane, it also contains organic acids and several heavy metals. Experimental results suggest that iron from the aqueous and DNAPL phases undergoes precipitation and dechlorination reactions at the DNAPL-water interface, contributing to the low interfacial tension and acidity of the DNAPL. Biological activity in the contaminated region can also contribute to the low interfacial tension. PCE degrading bacteria produce biosurfactants and adhere to the DNAPL-water interface when stressed by high tetrachloroethene or low dissolved oxygen concentrations. The presence of iron can reduce the interfacial tension by nearly an order of magnitude, while the PCE degraders reduced the interfacial tension by nearly 50%. Abiotic changes in the mineral characteristics were not found to be substantially different between contaminated and background samples. The research completed here begins to shed some insight into the complexities of DNAPL fate and migration at sites where co-disposal of many different waste products occurred. Quantifying the low interfacial tension of the SRS DNAPL helps to formulate a new conceptual picture of the subsurface DNAPL migration and provides an explanation of the limited effectiveness of remediation efforts. Alternative designs for remediation that are more effective for sites with DNAPL in fine grained media are required.

  5. Does river restoration affect diurnal and seasonal changes to surface water quality? A study along the Thur River, Switzerland.

    PubMed

    Chittoor Viswanathan, Vidhya; Molson, John; Schirmer, Mario

    2015-11-01

    Changes in river water quality were investigated along the lower reach of the Thur River, Switzerland, following river restoration and a summer storm event. River restoration and hydrological storm events can each cause dramatic changes to water quality by affecting various bio-geochemical processes in the river, but have to date not been well documented, especially in combination. Evaluating the success of river restoration is often restricted in large catchments due to a lack of high frequency water quality data, which are needed for process understanding. These challenges were addressed in this study by measuring water quality parameters including dissolved oxygen (DO), temperature, pH, electrical conductivity (EC), nitrate and dissolved organic carbon (DOC) with a high temporal frequency (15 min-1h) over selected time scales. In addition, the stable isotopes of water (δD and δ(18)O-H2O) as well as those of nitrate (δ(15)N-NO3(-) and δ(18)O-NO3(-)) were measured to follow changes in water quality in response to the hydrological changes in the river. To compare the spatial distribution of pre- and post-restoration water quality, the sampling stations were chosen upstream and downstream of the restored section. The diurnal and seasonal changes were monitored by conducting 24-hour campaigns in three seasons (winter, summer and autumn) in 2012 and 2013. The amplitude of the diurnal changes of the various observed parameters showed significant seasonal and spatial variability. Biological processes--mainly photosynthesis and respiration--were found to be the major drivers of these diurnal cycles. During low flow in autumn, a reduction of nitrate (attributed to assimilation by autotrophs) in the pre-dawn period and a production of DOC during the daytime (attributed to photosynthesis) were observed downstream of the restored site. Further, a summer storm event was found to override the influence of these biological processes that control the diurnal changes. High frequency daily monitoring of key water quality parameters over different seasons is shown to be essential in evaluating river restoration success. PMID:26057997

  6. Retrievals of precipitable water vapor using star photometry: Assessment with Raman lidar and link to sun photometry

    NASA Astrophysics Data System (ADS)

    Pérez-Ramírez, D.; Navas-Guzmán, F.; Lyamani, H.; Fernández-Gálvez, J.; Olmo, F. J.; Alados-Arboledas, L.

    2012-03-01

    This work deals with the applicability of a star photometer to retrieve precipitable water vapor (W) at nighttime by means of direct irradiance from stars using a 940 nm narrowband filter. Retrievals are assessed with simultaneous data from a Raman lidar system and linked with daytime values from a sun photometer using measurements taken from March to May 2007 at an urban site. Calibration of both the star and sun photometers was performed by the Modified Astronomical Langley Method. The retrieval of W from photometers is based on a look up table using a simplified expression for the water vapor transmittance and the relative optical water vapor air mass. This methodology presents a systematic uncertainty in W below 3% and 6% for sun and star photometry, respectively. Retrievals of W from star photometry were 9% above those obtained from the Raman lidar technique, but with a great agreement in the temporal evolution from both instruments. The link of daytime and nighttime values of W using sun and star photometers for a more extended database showed a smooth continuity between consecutive periods.

  7. Feasibility of spectro-photometry in X-rays (SPHINX) from the moon

    NASA Astrophysics Data System (ADS)

    Sarkar, Ritabrata; Chakrabarti, Sandip Kumar

    2010-08-01

    Doing space Astronomy on lunar surface has several advantages. We present here feasibility of an All Sky Monitoring Payload for Spectro-photometry in X-rays (SPHINX) which can be placed on a lander on the moon or in a space craft orbiting around the moon. The Si-PIN photo-diodes and CdTe crystals are used to detect solar flares, bright gamma bursts, soft gamma-ray repeaters from space and also X-ray fluorescence (XRF) from lunar surface. We present the complete Geant4 simulation to study the feasibility of such an instrument in presence of Cosmic Diffused X-Ray Background (CDXRB). We find that the signal to noise ratio is sufficient for moderate to bright GRBs (above 5 keV), for the quiet sun (up to 100 keV), solar flares, soft gamma-ray repeaters, X-ray Fluorescence (XRF) of lunar surface etc. This is a low-cost system which is capable of performing multiple tasks while stationed at the natural satellite of our planet.

  8. Shear Wave Velocity Profiles Determined from Surface Wave Measurements at Sites Affected by the August 15th, 2007 Earthquake in Peru

    NASA Astrophysics Data System (ADS)

    Rosenblad, B. L.; Bay, J. A.

    2008-05-01

    The shear wave velocity (Vs) profile of near-surface soils is a critical parameter for understanding recorded ground motions and predicting local site effects in an earthquake. In structural design, the Vs profile in the top 30 m is used to modify design response spectra to account for local soil effects. In addition, knowledge of the near- surface Vs profile at strong motion stations can be used to account for changes in frequency content and amplification caused by the local site conditions. Following the August 15th, 2007 earthquake in Peru, a field testing program was performed to measure Vs profiles in the top 20 to 30 m at twenty-two locations in the affected region. The measurements were performed primarily at the sites of damaged school buildings but were also performed at several strong motion station sites as well as a few locations where evidence of soil liquefaction was observed. Nineteen of the sites were located in the severely affected cities of Chincha, Ica, Pisco and Tambo de Mora, with the remaining three sites located in, Lima, Palpa and Paracus. The Vs profiles were determined from surface wave velocity measurements performed with an impact source. The objective of this paper is to present and discuss the range of Vs profile conditions encountered in the regions affected by the Pisco-Peru earthquake. In the city of Ica, the profiles generally exhibited gradually increasing velocities with depth, with velocities which rarely exceeded 400 m/s in the top 30 m. In contrast, the profiles measured in Pisco, often exhibited strong, shallow velocity contrasts with Vs increasing from less than 200 m/s at the surface to over 600 m/s at some sites. The profiles measured in Chincha generally fell in between the ranges measured in Ica and Pisco. Lastly, soil liquefaction was evident throughout Tambo de Mora on the coast of Peru. Measurements indicated very low shear wave velocities of 75 to 125 m/s in the top 4 m, which is consistent with the observed liquefaction in this region.

  9. Nanoparticles Affect PCR Primarily via Surface Interactions with PCR Components: Using Amino-Modified Silica-Coated Magnetic Nanoparticles as a Main Model.

    PubMed

    Bai, Yalong; Cui, Yan; Paoli, George C; Shi, Chunlei; Wang, Dapeng; Shi, Xianming

    2015-06-24

    Nanomaterials have been widely reported to affect the polymerase chain reaction (PCR). However, many studies in which these effects were observed were not comprehensive, and many of the proposed mechanisms have been primarily speculative. In this work, we used amino-modified silica-coated magnetic nanoparticles (ASMNPs, which can be collected very easily using an external magnetic field) as a model and compared them with gold nanoparticles (AuNPs, which have been studied extensively) to reveal the mechanisms by which nanoparticles affect PCR. We found that nanoparticles affect PCR primarily by binding to PCR components: (1) inhibition, (2) specifity, and (3) efficiency and yield of PCR are impacted. (1) Excess nanomaterials inhibit PCR by adsorbing to DNA polymerase, Mg(2+), oligonucleotide primers, or DNA templates. Nanoparticle surface-active groups are particularly important to this effect. (2, a) Nanomaterials do not inhibit nonspecific amplification products caused by false priming as previously surmised. It was shown that relatively low concentrations of nanoparticles inhibited the amplification of long amplicons, and increasing the amount of nanoparticles inhibited the amplification of short amplicons. This concentration phenomenon appears to be the result of the formation of "joints" upon the adsorption of ASMNPs to DNA templates. (b) Nanomaterials are able to inhibit nonspecific amplification products due to incomplete amplification by preferably adsorbing single-stranded incomplete amplification products. (3) Some types of nanomaterials, such as AuNPs, enhance the efficiency and yield of PCR because these types of nanoparticles can adsorb to single-stranded DNA more strongly than to double-stranded DNA. This behavior assists in the rapid and thorough denaturation of double-stranded DNA templates. Therefore, the interaction between the surface of nanoparticles and PCR components is sufficient to explain most of the effects of nanoparticles on PCR. PMID:26030087

  10. On modeling and nanoanalysis of caries-affected dentin surfaces restored with Zn-containing amalgam and in vitro oral function.

    PubMed

    Toledano, Manuel; Aguilera, Fátima S; Osorio, Estrella; López-López, Modesto T; Cabello, Inmaculada; Toledano-Osorio, Manuel; Osorio, Raquel

    2015-01-01

    The aim of this research was to assess the influence of mechanical loading on the ability of Zn-free versus Zn-containing amalgams to promote remineralization at the dentin interface. Sound and caries-affected dentin surfaces (CAD) were restored using Zn-free or Zn-containing dental amalgams. Midcoronal dentin surfaces were studied by (1) atomic force microscopy analysis (including plot and phase imaging, nanoindentation test [modulus of Young (Ei), nanoroughness measurements, and fibril diameter assessment], (2) Raman spectroscopy/cluster analysis, (3) x-ray diffraction, (4) field emission electron microscope and energy-dispersive analysis, for morphological, mechanical, and physicochemical characterization. Analyses were performed before amalgam placement and after amalgam removal, at 24 h and 3 weeks of load cycling. Zn-free and Zn-containing amalgams restorations promoted an increase in the modulus of Young of CAD surfaces, after 3 weeks of load cycling; at this time, Zn-containing amalgams attained higher Ei than Zn-free restorations. Zn-containing amalgams induced tubular occlusion after load cycling, in both sound and CAD. Zn free-amalgams promoted remineralization of both intertubular and peritubular dentin in CAD substrata. These minerals were identified as calcium-phosphate deposits and crystals as hydroxyl-apatite with augmented crystallographic maturity but with some components of lattice distortion. Crosslinking of collagen diminished and secondary structure of collagen increased in CAD substrate restored with Zn-containing amalgam after 3 weeks of load cycling, indicating an advanced preservation, molecular organization, and orientation of collagen fibrils after load cycling. Plot and phase images permitted to observe the topographical changes which were promoted by the mineral deposits; in general, the indexes related to higher remineralization gave rise to a decrease of nanoroughness and an augmentation of the bandwidth of the collagen fibrils. Zn-containing amalgam restorations submitted to mechanical stimuli promote remineralization of the partially mineral-depleted subjacent substrate at the caries-affected dentin. PMID:26483350

  11. CCD photometry of globular clusters in NGC 3377

    NASA Astrophysics Data System (ADS)

    Harris, William E.

    1990-08-01

    New CCD photometry to a limit B = 24.3 is presented for a sample of globular clusters around NGC 337, an intermediate-size elliptical in the Leo group. Assuming that the luminosity function of its globular clusters follows the same log-normal form as in other galaxies, a peak frequency level (turnover magnitude) of B(0) = 23.35 + or - 0.40 is derived for a combined sample of clusters in NGC 3377 and NGC 3379. Matching this to the globular clusters in the Milky Way then gives a distance modulus (m - M)B (Leo) = 30.2, or d = (10.7 + or - 2.2) Mpc, in good agreement with other recent distance-scale methods. The clusters around NGC 3377 follow a highly ellipsoidal space distribution; two different tests show that their distribution is at least as flattened as the E6 shape of the galaxy itself.

  12. CCD photometry of globular clusters in NGC 3377

    SciTech Connect

    Harris, W.E. )

    1990-09-01

    New CCD photometry to a limit B = 24.3 is presented for a sample of globular clusters around NGC 337, an intermediate-size elliptical in the Leo group. Assuming that the luminosity function of its globular clusters follows the same log-normal form as in other galaxies, a peak frequency level (turnover magnitude) of B(0) = 23.35 + or - 0.40 is derived for a combined sample of clusters in NGC 3377 and NGC 3379. Matching this to the globular clusters in the Milky Way then gives a distance modulus (m - M)B (Leo) = 30.2, or d = (10.7 + or - 2.2) Mpc, in good agreement with other recent distance-scale methods. The clusters around NGC 3377 follow a highly ellipsoidal space distribution; two different tests show that their distribution is at least as flattened as the E6 shape of the galaxy itself. 31 refs.

  13. Results of the 2015 Mexican Asteroid Photometry Campaign

    NASA Astrophysics Data System (ADS)

    Sada, Pedro V.; Navarro-Meza, Samuel; Reyes-Ruiz, Mauricio; Olguin, Lorenzo L.; Saucedo, Julio C.; Loera-Gonzalez, Pablo

    2016-04-01

    The 2015 Mexican Asteroid Photometry Campaign was organized at the 2nd National Planetary Astrophysics Workshop held in 2015 March at the Universidad Autónoma de Nuevo León in Monterrey, México. Three asteroids were selected for coordinated observations from several Mexican observatories. We report full lightcurves for the main-belt asteroid 1084 Tamariwa (P = 6.195 ± 0.001 h) and near-Earth asteroid (NEA) 4055 Magellan (P = 7.479 ± 0.001 h). Asteroid 1466 Mundleria was also observed on eight nights but no lightcurve was obtained because of its faintness, a crowded field-of-view, and low amplitude (<0.03 mag).

  14. Asteroid models from photometry and complementary data sources

    NASA Astrophysics Data System (ADS)

    Kaasalainen, Mikko

    2016-05-01

    I discuss inversion methods for asteroid shape and spin reconstruction with photometry (lightcurves) and complementary data sources such as adaptive optics or other images, occultation timings, interferometry, and range-Doppler radar data. These are essentially different sampling modes (generalized projections) of plane-of-sky images. An important concept in this approach is the optimal weighting of the various data modes. The maximum compatibility estimate, a multi-modal generalization of the maximum likelihood estimate, can be used for this purpose. I discuss the fundamental properties of lightcurve inversion by examining the two-dimensional case that, though not usable in our three-dimensional world, is simple to analyze, and it shares essentially the same uniqueness and stability properties as the 3-D case. After this, I review the main aspects of 3-D shape representations, lightcurve inversion, and the inclusion of complementary data.

  15. Evaluation of urine culture screening by light-scatter photometry

    SciTech Connect

    Hale, D.C.; Thrupp, L.D.; Matsen, J.M.

    1981-08-01

    Urine screening for bacteriuria by light-scatter photometry (Autobac) was evaluated for accuracy and compared with a colony count by the calibrated loop method. Incubation time, inoculum size, precision, and interference of particulate matter were evaluated in an effort to standardize the screening procedure. Results showed that urines could be accurately screened for Enterobacteriaceae by inoculating a single Autobac cuvette chamber with 0.1 or 0.2 ml of urine and determining the voltage change after four hours. A change of greater than or equal to 0.2 units indicates significant bacteriuria. Decreased accuracy was noted for urines having greater than 10(5) cfu/ml of Pseudomonas species or gram-positive cocci, possibly because these organisms grow more slowly.

  16. USING PHOTOMETRY TO PROBE THE CIRCUMSTELLAR ENVIRONMENT OF {delta} SCORPII

    SciTech Connect

    Jones, C. E.; Wiegert, P. A.; Cyr, R. P.; Halonen, R. J.; Tycner, C.; Henry, G. W.; Muterspaugh, M. W.

    2013-05-15

    We acquired Johnson BV photometry of the binary Be disk system {delta} Scorpii during its 2009, 2010, 2011, and 2012 observing seasons and used it to probe the innermost regions of the disk. We found that several disk building events have occurred during this time, resulting in an overall brightening in the V band and reddening of the system. In addition to these long-term trends, we found cyclical variability in each observing season on timescales between 60 and 100 days. We were able to reproduce the changes in the magnitude and color of {delta} Sco using our theoretical models and found that variable mass-loss rates in the range 2.5-7.0 Multiplication-Sign 10{sup -9} M{sub Sun} yr{sup -1} over {approx}35 days can reproduce the observed increase in brightness.

  17. Three years of photometry of IM Pegasi = HR 8703

    NASA Technical Reports Server (NTRS)

    Eaton, J. A.; Hall, D. S.; Henry, G. W.; Lovell, L. P.; Stephan, C. A.; Chambliss, C. R.; Detterline, P. K.; Landis, H. J.; Louth, H.; Renner, T. R.

    1983-01-01

    Differential photometry of this K1 IV-III p RS CVn-type binary in 1978-79, 1979-80, and 1980-81 at eight different observatories shows that the variability, discovered originally by Herbst, is periodic. The mean of three different determinations of the photometric period was 24(d).39 + or 0(d).03, about 1 percent shorter than the orbital period of 24(d).649 determined spectroscopically by Harper. The total range observed during these three years was for V from 5(m).60 to 5(m).85. The light curve was nearly sinusoidal but always noticieably asymmetric, with the sense reversing sometime between 1979-80 and 1980-81.

  18. Prelude to, and Nature of the Space Photometry Revolution

    NASA Astrophysics Data System (ADS)

    Gilliland, Ronald L.

    2015-09-01

    It is now less than a decade since CoRoT initiated the space photometry revolution with breakthrough discoveries, and five years since Kepler started a series of similar advances. I'll set the context for this revolution noting the status of asteroseismology and exoplanet discovery as it was 15-25 years ago in order to give perspective on why it is not mere hyperbole to claim CoRoT and Kepler fostered a revolution in our sciences. Primary events setting up the revolution will be recounted. I'll continue with noting the major discoveries in hand, and how asteroseismology and exoplanet studies, and indeed our approach to doing science, have been forever changed thanks to these spectacular missions.

  19. Spitzer IRAC Photometry for Time Series in Crowded Fields

    NASA Astrophysics Data System (ADS)

    Calchi Novati, S.; Gould, A.; Yee, J. C.; Beichman, C.; Bryden, G.; Carey, S.; Fausnaugh, M.; Gaudi, B. S.; Henderson, C. B.; Pogge, R. W.; Shvartzvald, Y.; Wibking, B.; Zhu, W.; Spitzer Team; Udalski, A.; Poleski, R.; Pawlak, M.; Szymański, M. K.; Skowron, J.; Mróz, P.; Kozłowski, S.; Wyrzykowski, Ł.; Pietrukowicz, P.; Pietrzyński, G.; Soszyński, I.; Ulaczyk, K.; OGLE Group

    2015-12-01

    We develop a new photometry algorithm that is optimized for the Infrared Array Camera (IRAC) Spitzer time series in crowded fields and that is particularly adapted to faint or heavily blended targets. We apply this to the 170 targets from the 2015 Spitzer microlensing campaign and present the results of three variants of this algorithm in an online catalog. We present detailed accounts of the application of this algorithm to two difficult cases, one very faint and the other very crowded. Several of Spitzer's instrumental characteristics that drive the specific features of this algorithm are shared by Kepler and WFIRST, implying that these features may prove to be a useful starting point for algorithms designed for microlensing campaigns by these other missions.

  20. Steps toward a physical calibration of UBV photometry

    NASA Astrophysics Data System (ADS)

    Buser, R.; Kurucz, R. L.

    The large data base of photoelectric measurements on the Johnson UBV system has been a primary source of information in many fields of astrophysical interest. The availability of UBV data for virtually all types of stars known to make up the stellar populations in galaxies requires a continued effort toward establishing a fully physical calibration of these data in order to propagate effectively the improving knowledge on stellar evolution and stellar atmospheres (i.e., the HR diagram) through the observations relevant to the structure and evolution of the galaxies. One of the major links in this long chain of scientific progress is provided by the synthesis of stellar photometric properties from theoretical model atmospheres. This paper will briefly address some of the basic problems involved in the synthetic color calculations and discuss the theoretical calibration of UBV photometry as obtained from various grids of model atmospheres covering a large range of stellar types.

  1. ColorPro: PSF-corrected aperture-matched photometry

    NASA Astrophysics Data System (ADS)

    Coe, Dan; Benitez, Narciso

    2015-08-01

    ColorPro automatically obtains robust colors across images of varied PSF. To correct for the flux lost in images with poorer PSF, the "detection image" is blurred to match the PSF of these other images, allowing observation of how much flux is lost. All photometry is performed in the highest resolution frame (images being aligned given WCS information in the FITS headers), and identical apertures are used in every image. Usually isophotal apertures are used, as determined by SExtractor (ascl:1010.064). Using SExSeg (ascl:1508.006), object aperture definitions can be pre-defined and object detections from different image filters can be combined automatically into a single comprehensive "segmentation map." After producing the final photometric catalog, ColorPro can automatically run BPZ (ascl:1108.011) to obtain Bayesian Photometric Redshifts.

  2. Towards photometry pipeline of the Indonesian space surveillance system

    NASA Astrophysics Data System (ADS)

    Priyatikanto, Rhorom; Religia, Bahar; Rachman, Abdul; Dani, Tiar

    2015-09-01

    Optical observation through sub-meter telescope equipped with CCD camera becomes alternative method for increasing orbital debris detection and surveillance. This observational mode is expected to eye medium-sized objects in higher orbits (e.g. MEO, GTO, GSO & GEO), beyond the reach of usual radar system. However, such observation of fast moving objects demands special treatment and analysis technique. In this study, we performed photometric analysis of the satellite track images photographed using rehabilitated Schmidt Bima Sakti telescope in Bosscha Observatory. The Hough transformation was implemented to automatically detect linear streak from the images. From this analysis and comparison to USSPACECOM catalog, two satellites were identified and associated with inactive Thuraya-3 satellite and Satcom-3 debris which are located at geostationary orbit. Further aperture photometry analysis revealed the periodicity of tumbling Satcom-3 debris. In the near future, it is not impossible to apply similar scheme to establish an analysis pipeline for optical space surveillance system hosted in Indonesia.

  3. The symbiosis of photometry and radial-velocity measurements

    NASA Technical Reports Server (NTRS)

    Cochran, William D.

    1994-01-01

    The FRESIP mission is optimized to detect the inner planets of a planetary system. According to the current paradigm of planet formation, these planets will probably be small Earth-sized objects. Ground-based radial-velocity programs now have the sensitivity to detect Jovian-mass planets in orbit around bright solar-type stars. We expect the more massive planets to form in the outer regions of a proto-stellar nebula. These two types of measurements will very nicely complement each other, as they have highest detection probability for very different types of planets. The combination of FRESIP photometry and ground-based spectra will provide independent confirmation of the existence of planetary systems in orbit around other stars. Such detection of both terrestrial and Jovian planets in orbit around the same star is essential to test our understanding of planet formation.

  4. An interactive modular design for computerized photometry in spectrochemical analysis

    NASA Technical Reports Server (NTRS)

    Bair, V. L.

    1980-01-01

    A general functional description of totally automatic photometry of emission spectra is not available for an operating environment in which the sample compositions and analysis procedures are low-volume and non-routine. The advantages of using an interactive approach to computer control in such an operating environment are demonstrated. This approach includes modular subroutines selected at multiple-option, menu-style decision points. This style of programming is used to trace elemental determinations, including the automated reading of spectrographic plates produced by a 3.4 m Ebert mount spectrograph using a dc-arc in an argon atmosphere. The simplified control logic and modular subroutine approach facilitates innovative research and program development, yet is easily adapted to routine tasks. Operator confidence and control are increased by the built-in options including degree of automation, amount of intermediate data printed out, amount of user prompting, and multidirectional decision points.

  5. Flaring on RS CVn systems: Results from EUVE Photometry

    NASA Astrophysics Data System (ADS)

    Osten, R. A.; Brown, A.; Ayres, T. R.

    We present broadband EUV photometry for a sample of RS CVn systems observed with the Deep Survey Spectrometer and Right Angle Program (RAP) Scanners on the Extreme Ultraviolet Explorer (EUVE). We have developed robust data analysis and light curve software for the interpretation of these data. Large-scale flaring activity is seen on 15 of the 18 systems studied. These binaries cover a range in orbital period of 0.7 days to 21 days and include a mixture of giant, subgiant, and dwarf luminosity classes. For many systems the photometric coverage extends over several orbital periods and flaring is unambiguously characterized. We present statistics on the distribution of variability in the survey. Correlations of flaring with binary properties are examined.

  6. Narrow-band X-ray photometry as a tool for studying galaxy and cluster mass distributions

    NASA Astrophysics Data System (ADS)

    Humphrey, Philip J.; Buote, David A.

    2013-12-01

    We explore the utility of narrow-band X-ray surface photometry as a tool for making fully Bayesian, hydrostatic mass measurements of clusters of galaxies, groups and early-type galaxies. We demonstrate that it is sufficient to measure the surface photometry with the Chandra X-ray Observatory in only three (rest frame) bands (0.5-0.9, 0.9-2.0 and 2.0-7.0 keV) in order to constrain the temperature, density and abundance of the hot interstellar medium (ISM). Adopting parametrized models for the mass distribution and radial entropy profile and assuming spherical symmetry, we show that the constraints on the mass and thermodynamic properties of the ISM that are obtained by fitting data from all three bands simultaneously are comparable to those obtained by fitting similar models to the temperature and density profiles derived from spatially resolved spectroscopy, as is typically done. We demonstrate that the constraints can be significantly tightened when exploiting a recently derived, empirical relationship between the gas fraction and the entropy profile at large scales, eliminating arbitrary extrapolations at large radii. This `Scaled Adiabatic Model' is well suited to modest signal-to-noise ratio data, and we show that accurate, precise measurements of the global system properties are inferred when employing it to fit data from even very shallow, snapshot X-ray observations. The well-defined asymptotic behaviour of the model also makes it ideally suited for use in Sunyaev-Zeldovich studies of galaxy clusters.

  7. Recovering physical properties from narrow-band photometry

    NASA Astrophysics Data System (ADS)

    Schoenell, W.; Cid Fernandes, R.; Benítez, N.; Vale Asari, N.

    2013-05-01

    Our aim in this work is to answer, using simulated narrow-band photometry data, the following general question: What can we learn about galaxies from these new generation cosmological surveys? For instance, can we estimate stellar age and metallicity distributions? Can we separate star-forming galaxies from AGN? Can we measure emission lines, nebular abundances and extinction? With what precision? To accomplish this, we selected a sample of about 300k galaxies with good S/N from the SDSS and divided them in two groups: 200k objects and a template library of 100k. We corrected the spectra to z = 0 and converted them to filter fluxes. Using a statistical approach, we calculated a Probability Distribution Function (PDF) for each property of each object and the library. Since we have the properties of all the data from the STARLIGHT-SDSS database, we could compare them with the results obtained from summaries of the PDF (mean, median, etc). Our results shows that we retrieve the weighted average of the log of the galaxy age with a good error margin (σ ≈ 0.1 - 0.2 dex), and similarly for the physical properties such as mass-to-light ratio, mean stellar metallicity, etc. Furthermore, our main result is that we can derive emission line intensities and ratios with similar precision. This makes this method unique in comparison to the other methods on the market to analyze photometry data and shows that, from the point of view of galaxy studies, future photometric surveys will be much more useful than anticipated.

  8. Far-ultraviolet photometry of the globular cluster omega Cen

    NASA Technical Reports Server (NTRS)

    Whitney, Jonathan H.; O'Connell, Robert W.; Rood, Robert T.; Dorman, Ben; Landsman, Wayne B.; Cheng, K.-P.; Bohlin, Ralph C.; Hintzen, Paul M. N.; Roberts, Morton S.; Smith, Andrew M.

    1994-01-01

    We present far-ultraviolet images of the globular cluster omega Centauri obtained with the Ultraviolet Imaging Telescope (UIT) during the 1990 December Astro-1 mission. A total of 1957 sources are detected at 1620 A to a limiting ultraviolet (UV) magnitude of 16.4 in the central 24 min diameter region of the field and a limit of 15.6 over the remainder of the 40 min diameter field. Over 1400 of these sources are matched with stars on a Stroemgren u band charge coupled devices (CCD) frame obtained with the Cerro Tololo Inter-American Observatory (CTIO) 0.9 m telescope to produce a (far-UV, u) color-magnitude diagram (CMD). Completeness of the sample and error estimates are determined by photometry of artificial stars added to the images. The horizontal branch (HB) of the CMD is heavily populated hotter than 9000 K. A large number of 'extreme HB' stars are found hotter than a conspicuous break in the HB at T(sub e) approximately 16000 K. There is also a significant population of stars above the HB, the brightest of which is 4 mag brighter than the HB. Most of the hotter of these appear to be 'AGB-manque' or 'Post-Early Asymptotic Giant Branch' stars. We compare the observations to recent theoretical evolutionary tracks for the zero-age HB and subsequent phases. The tracks match the data well, with the exception of the hotter HB stars, many of which fall below the zero-age horizontal branch. It is unclear as yet whether these are a special population or an artifact of errors in the models or photometry. We identify 33 stars with T(sub e) greater than or approximately = 50000 K, which are hotter than zero-age HB stars with envelope masses of 0.003 solar mass.

  9. Spectral properties of near-Earth and Mars-crossing asteroids using Sloan photometry

    NASA Astrophysics Data System (ADS)

    Carry, B.; Solano, E.; Eggl, S.; DeMeo, F. E.

    2016-04-01

    The nature and origin of the asteroids orbiting in near-Earth space, including those on a potentially hazardous trajectory, is of both scientific interest and practical importance. We aim here at determining the taxonomy of a large sample of near-Earth and Mars-crosser asteroids and analyze the distribution of these classes with orbit. We use this distribution to identify the source regions of near-Earth objects and to study the strength of planetary encounters to refresh asteroid surfaces. We measure the photometry of these asteroids over four filters at visible wavelengths on images taken by the Sloan Digital Sky Survey (SDSS). These colors are used to classify the asteroids into a taxonomy consistent with the widely used Bus-DeMeo taxonomy (DeMeo et al. [2009]. Icarus 202, 160-180) based on visible and near-infrared spectroscopy. We report here on the taxonomic classification of 206 near-Earth and 776 Mars-crosser asteroids determined from SDSS photometry, representing an increase of 40% and 663% of known taxonomy classifications in these populations. Using the source region mapper by Greenstreet et al. (Greenstreet, S., Ngo, H., Gladman, B. [2012]. Icarus, 217, 355-366), we compare for the first time the taxonomic distribution among near-Earth and main-belt asteroids of similar diameters. Both distributions agree at the few percent level for the inner part of the main belt and we confirm this region as a main source of near-Earth objects. The effect of planetary encounters on asteroid surfaces are also studied by developing a simple model of forces acting on a surface grain during planetary encounter, which provides the minimum distance at which a close approach should occur to trigger resurfacing events. By integrating numerically the orbit of the 519 S-type and 46 Q-type asteroids in our sample back in time for 500,000 years and monitoring their encounter distance with Venus, Earth, Mars, and Jupiter, we seek to understand the conditions for resurfacing events. The population of Q-type is found to present statistically more encounters with Venus and the Earth than S-types, although both S- and Q-types present the same amount of encounters with Mars.

  10. Time-series Photometry of the Pre-Main Sequence Binary V4046 Sgr: Testing the Accretion Stream Theory

    NASA Astrophysics Data System (ADS)

    Tofflemire, Benjamin M.; Mathieu, Robert D.; Ardila, David R.; Ciardi, David R.

    2015-01-01

    Most stars are born in binaries, and the evolution of protostellar disks in pre-main sequence (PMS) binary stars is a current frontier of star formation research. PMS binary stars can have up to three accretion disks: two circumstellar disks and a circumbinary disk separated by a dynamically cleared gap. Theory suggests that mass may periodically flow in an accretion stream from a circumbinary disk across the gap onto circumstellar disks or stellar surfaces. Thus, accretion in PMS binaries is controlled by not only radiation, disk viscosity, and magnetic fields, but also by orbital dynamics.As part of a larger, ongoing effort to characterize mass accretion in young binary systems, we test the predictions of the binary accretion stream theory through continuous, multi-orbit, multi-color optical and near-infrared (NIR) time-series photometry. Observations such as these are capable of detecting and characterizing these modulated accretion streams, if they are generally present. Broad-band blue and ultraviolet photometry trace the accretion luminosity and photospheric temperature while NIR photometry provide a measurement of warm circumstellar material, all as a function of orbital phase. The predicted phase and magnitude of enhanced accretion are highly dependent on the binary orbital parameters and as such, our campaign focuses on 10 PMS binaries of varying periods and eccentricities. Here we present multi-color optical (U, B,V, R), narrowband (Hα), and multi-color NIR (J, H) lightcurves of the PMS binary V4046 Sgr (P=2.42 days) obtained with the SMARTS 1.3m telescope and LCOGT 1m telescope network. These results act to showcase the quality and breadth of data we have, or are currently obtaining, for each of the PMS binaries in our sample. With the full characterization of our sample, these observations will guide an extension of the accretion paradigm from single young stars to multiple systems.

  11. EXTENDED PHOTOMETRY FOR THE DEEP2 GALAXY REDSHIFT SURVEY: A TESTBED FOR PHOTOMETRIC REDSHIFT EXPERIMENTS

    SciTech Connect

    Matthews, Daniel J.; Newman, Jeffrey A.; Coil, Alison L.; Cooper, Michael C.; Gwyn, Stephen D. J. E-mail: janewman@pitt.edu E-mail: m.cooper@uci.edu

    2013-02-15

    This paper describes a new catalog that supplements the existing DEEP2 Galaxy Redshift Survey photometric and spectroscopic catalogs with ugriz photometry from two other surveys: the Canada-France-Hawaii Legacy Survey (CFHTLS) and the Sloan Digital Sky Survey (SDSS). Each catalog is cross-matched by position on the sky in order to assign ugriz photometry to objects in the DEEP2 catalogs. We have recalibrated the CFHTLS photometry where it overlaps DEEP2 in order to provide a more uniform data set. We have also used this improved photometry to predict DEEP2 BRI photometry in regions where only poorer measurements were available previously. In addition, we have included improved astrometry tied to SDSS rather than USNO-A2.0 for all DEEP2 objects. In total this catalog contains {approx}27, 000 objects with full ugriz photometry as well as robust spectroscopic redshift measurements, 64% of which have r > 23. By combining the secure and accurate redshifts of the DEEP2 Galaxy Redshift Survey with ugriz photometry, we have created a catalog that can be used as an excellent testbed for future photo-z studies, including tests of algorithms for surveys such as LSST and DES.

  12. Wide Field Near-infrared Photometry of 12 Galactic Globular Clusters: Observations Versus Models on the Red Giant Branch

    NASA Astrophysics Data System (ADS)

    Cohen, Roger E.; Hempel, Maren; Mauro, Francesco; Geisler, Douglas; Alonso-Garcia, Javier; Kinemuchi, Karen

    2015-12-01

    We present wide field near-infrared (near-IR) photometry of 12 Galactic globular clusters, typically extending from the tip of the cluster red giant branch (RGB) to the main sequence turnoff. Using recent homogenous values of cluster distance, reddening and metallicity, the resulting photometry is directly compared to the predictions of several recent libraries of stellar evolutionary models. Of the sets of models investigated, Dartmouth and Victoria-Regina models best reproduce the observed RGB morphology, albeit with offsets in J-{K}S color which vary in their significance in light of all sources of observational uncertainty. Therefore, we also present newly recalibrated relations between near-IR photometric indices describing the upper RGB versus cluster iron abundance as well as global metallicity. The influence of enhancements in alpha elements and helium are analyzed, and we find that the former affect the morphology of the upper RGB in accord with model predictions. Meanwhile, the empirical relations we derive are in good agreement with previous results, and minor discrepancies can likely be attributed to differences in the assumed cluster distances and reddenings. In addition, we present measurements of the horizontal branch (HB) and RGB bump magnitudes, finding a non-negligible dependence of the near-IR HB magnitude on cluster metallicity. Lastly, we discuss the influence of assumed cluster distances, reddenings and metallicities on our results, finding that our empirical relations are generally insensitive to these factors to within their uncertainties.

  13. The AAVSO Photoelectric Photometry Program in Its Scientific and Socio-Historic Context

    NASA Astrophysics Data System (ADS)

    Percy, J. R.

    2012-06-01

    In this paper, I review the work of the AAVSO in the area of photoelectric photometry (PEP). This work was influenced by several trends: in science, in technology, and in the sociology of amateur astronomy. Through the 1980s, the AAVSO photoelectric photometry program competed with other such programs and, in recent years, has been overshadowed by CCD photometry programs. Nevertheless, the AAVSO PEP program has, through careful organization, motivation, and feedback, produced extensive scientific results, and can continue to do so. In the case of my own research, AAVSO PEP observations have also contributed significantly to the education of my students.

  14. CCD BVRI photometry of the open clusters NGC 7142 and NGC 2281

    NASA Astrophysics Data System (ADS)

    Punanova, A. F.; Krushinsky, V. V.; Loktin, A. V.; Burdanov, A. Y.; Popov, A. A.; Avvakumova, E. A.; Zalozhnih, I. S.

    Photometry of stars up to 17 mag in the field of the open clusters NGC 7142 and NGC 2281 in BVRI filters was performed to search for new short-term variable stars. Seventeen variable stars were found using robust median statistics and 18 were suspected to be variable. We separated probable cluster members using proper motions from UCAC3 and our photometric diagrams. Also we used our BVRI photometry and JHK photometry from 2MASS to improve age and reddening for the clusters.

  15. Surface orientation affects the direction of cone growth by Leptolyngbya sp. strain C1, a likely architect of coniform structures Octopus Spring (Yellowstone National Park).

    PubMed

    Reyes, Kristina; Gonzalez, Nicolas I; Stewart, Joshua; Ospino, Frank; Nguyen, Dickie; Cho, David T; Ghahremani, Nahal; Spear, John R; Johnson, Hope A

    2013-02-01

    Laminated, microbially produced stromatolites within the rock record provide some of the earliest evidence for life on Earth. The chemical, physical, and biological factors that lead to the initiation of these organosedimentary structures and shape their morphology are unclear. Modern coniform structures with morphological features similar to stromatolites are found on the surface of cyanobacterial/microbial mats. They display a vertical element of growth, can have lamination, can be lithified, and observably grow with time. To begin to understand the microbial processes and interactions required for cone formation, we determined the phylogenetic composition of the microbial community of a coniform structure from a cyanobacterial mat at Octopus Spring, Yellowstone National Park, and reconstituted coniform structures in vitro. The 16S rRNA clone library from the coniform structure was dominated by Leptolyngbya sp. Other cyanobacteria and heterotrophic bacteria were present in much lower abundance. The same Leptolyngbya sp. identified in the clone library was also enriched in the laboratory and could produce cones in vitro. When coniform structures were cultivated in the laboratory, the initial incubation conditions were found to influence coniform morphology. In addition, both the angle of illumination and the orientation of the surface affected the angle of cone formation demonstrating how external factors can influence coniform, and likely, stromatolite morphology. PMID:23241986

  16. Synthetic photometry for M and K giants and stellar evolution: hydrostatic dust-free model atmospheres and chemical abundances

    NASA Astrophysics Data System (ADS)

    Aringer, B.; Girardi, L.; Nowotny, W.; Marigo, P.; Bressan, A.

    2016-04-01

    Based on a grid of hydrostatic spherical COMARCS models for cool stars, we have calculated observable properties of these objects, which will be mainly used in combination with stellar evolution tracks and population synthesis tools. The high-resolution opacity sampling and low-resolution convolved spectra as well as bolometric corrections for a large number of filter systems are made electronically available. We exploit those data to study the effect of mass, C/O ratio and nitrogen abundance on the photometry of K and M giants. Depending on effective temperature, surface gravity and the chosen wavelength ranges, variations of the investigated parameters cause very weak to moderate and, in the case of C/O values close to 1, even strong shifts of the colours. For the usage with stellar evolution calculations, they will be treated as correction factors applied to the results of an interpolation in the main quantities. When we compare the synthetic photometry to observed relations and to data from the Galactic bulge, we find in general a good agreement. Deviations appear for the coolest giants showing pulsations, mass-loss and dust shells, which cannot be described by hydrostatic models.

  17. Photometry and Spectroscopy of BD+35 1111 in M38

    NASA Astrophysics Data System (ADS)

    Souza, Steven P.; Kwitter, Karen B.; Sami, Mona; Beltz-Mohrmann, Gillian

    2014-06-01

    BD+35 1111 is a ~10.5-magnitude star in the field of M38, an open cluster that has been a target of our ongoing study of Hα emission variability in massive stars via narrowband CCD photometry (e.g. Souza, Davis, and Teich 2013, BAAS. 45, PM354.22). BD+35 1111 has no MKK classification in the literature, and is not listed as variable in GCVS, VSX, or NSVS. It is included, with no further characterization, in both the Vatican and Kohoutek catalogs of emission line stars. Using inhomogeneous ensemble photometry (e.g. Bhatti, Richmond, Ford, and Petro 2010, ApJ Supp., 186, 233), we find it to be an irregular variable with a range of ~0.15 mag. To further understand this star we obtained a medium-resolution spectrum using the DIS spectrograph on the ARC 3.5-meter telescope at Apache Point Observatory. We classify BD+35 1111 as B2Ve, the only confirmed Be star in the field of M38. This raises the question of membership, since the age of M38 is likely 250 Ma or greater (Pandey et al. 2007, Publ. Astron. Soc. Japan 59, 547). From published B and V magnitudes we find a nominal distance to BD+35 1111 of 1.6 kpc, but with a range of 1.3 to 2.0 kpc, marginally consistent with distance estimates for M38 ranging from 1.0 to 1.4 kpc. If a member, BD+35 1111 is a candidate blue straggler. If not, it may have escaped from a nearby younger cluster, possibly Kronberger 1 (Kronberger et al. 2006, A&A 447, 921), which has the right heliocentric distance and age. The notion that BD+35 1111 is behind M38 is supported by its reddening of EB-V ~ 0.5, significantly higher than for M38 itself 0.24). We gratefully acknowledge support for student research from NSF grant AST-1005024 to the Keck Northeast Astronomy Consortium, Williams College, and NASA via an American Astronomical Society Small Research Grant.

  18. Infrared photometry and polarimetry of Cygnus X-3

    NASA Technical Reports Server (NTRS)

    Jones, Terry Jay; Gehrz, Robert D.; Kobulnicky, Henry A.; Molnar, Lawrence A.; Howard, Eric M.

    1994-01-01

    We present photometry and linear polarimetry of Cygnus X-3 at K (2.2 micrometers) obtained over a 5 yr period. Photometry and polarimetry at J, H, and K of nearby field stars is also presented. From an analysis of these data we find: (1) Using the x-ray ephemeris of Kitamoto et al. (ApJ, 384, 263 (1992), including the first and second derivatives of the period, the leading edge of the decline to minimum in the quiescent K light curve has not changed in phase since 1974. The duration of the minimum in the light curve has changed significantly between different epochs, becoming much broader in 1993 than it was previously. (2) In addition to an interstellar polarization component, it is likely Cyg X-3 has an intrinsic polarization component that is variable. The variations in the polarization do not show any diagnostic pattern with orbital phase. A crude analysis of the polarization suggests the intrinsic polarization of Cyg X-3 has a mean position angle of approximately 12 deg, nearly the same as the direction of the expanding radio lobes. This is consistent with circumstellar electrons scattering in an equatorial disk that is perpendicular to the lobe axis. (3) The mean position angle for the interstellar polarization in the direction of Cyg X-3 is 150 deg. This is nearly perpendicular to the axis of interstellar radio scattering seen in the extended (Very Long Baseline Inteferometry (VLBI) images. Since the position angle of interstellar polarization is the same as the projected magnetic field direction, this suggests the interstellar (not circumstellar) scattering must be taking place perpendicular to the interstellar magnetic field lines. (4) Cyg X-3 was observed at K during a flare on 1992 September 30 with a temporal resolution of 6 s. The flaring had rise and fall times of approximately 50 s with peak intensities up to 80 mJy. The flux between individual flare events never dropped to quiescent levels for the duration of our observations (approximately 2000 s).

  19. VizieR Online Data Catalog: General Catalog of Photometry of Galaxies (Longo+ 1983)

    NASA Astrophysics Data System (ADS)

    Longo, G.; de Vaucouleurs, A.

    1994-01-01

    Details of the integrated photometry of galaxies in the UBV system (generally through circular apertures centered at the nucleus) published prior to 1963 were given in three appendices to the (First) Reference Catalogue of Bright Galaxies (RCBG = RC1). The publication of an updated listing in the Second Reference Catalogue (RC2) has been requested since then. The present catalogue contains no less than 16,680 observations of 3,578 galaxies generally brighter than the 16-th V-band magnitude collected from 150 different sources, including several recent unpublished series from McDonald and Siding Spring Observatories. We excluded only the numerous galaxies fainter than this magnitude, and the numerous observations of the nuclei of Seyfert galaxies and variable N-galaxies through small apertures published after 1972-73 which add little or no new information on the magnitude-aperture curve of the underlying galaxy. In addition to the measured magnitudes and colors, the important notes relative to each observation were extracted from the original publications and/or our own unpublished records. This is necessary for a proper interpretation of the raw data which are often affected by field stars, nearby companion galaxies, centering difficulties, and of course weather conditions. We have generally rejected photographic observations made through undefined apertures and photoelectric observations not directory transformable to the UBV system. the transformation equations adopted for observations not originally in the UBV system are given in Table 1, after RC1 (Tables 10, 11 and 12), RC2 (Table 11) and de Vaucouleurs (1961). Alternative transformations are indicated in the notes to Table 1. (* Table 1 of the published catalogue is not archived here. -- CDS) Altogether the catalogue contains 12,796 observations of 2086 NGC objects, 1059 observations of 303 IC objects, and 2825 observations of 1189 anonymous objects. This is still far insufficient for coverage of galaxies in RC2 and those anticipated in future RC3. The need for large systematic programs of photoelectric aperture photometry of galaxies in the U,B,V system remains as pressing as ever. Observatories should consider dedicating small telescopes to this urgent task. In this respect the present catalogue should be helpful to identify unobserved or insufficiently observed objects. Total magnitudes and colors, and other photometric parameters derived from the present catalogue of raw data will be included in the RC3. (1 data file).

  20. THE ARAUCARIA PROJECT. A DISTANCE DETERMINATION TO THE LOCAL GROUP SPIRAL M33 FROM NEAR-INFRARED PHOTOMETRY OF CEPHEID VARIABLES

    SciTech Connect

    Gieren, Wolfgang; Pietrzynski, Grzegorz; Graczyk, Dariusz E-mail: pietrzyn@hubble.cfm.udec.cl; and others

    2013-08-10

    Motivated by an amazing range of reported distances to the nearby Local Group spiral galaxy M33, we have obtained deep near-infrared photometry for 26 long-period Cepheids in this galaxy with the ESO Very Large Telescope. From the data, we constructed period-luminosity relations in the J and K bands which together with previous optical VI photometry for the Cepheids by Macri et al. were used to determine the true distance modulus of M33, and the mean reddening affecting the Cepheid sample with the multiwavelength fit method developed in the Araucaria Project. We find a true distance modulus of 24.62 for M33, with a total uncertainty of {+-}0.07 mag which is dominated by the uncertainty on the photometric zero points in our photometry. The reddening is determined as E(B - V) = 0.19 {+-} 0.02, in agreement with the value used by the Hubble Space Telescope Key Project of Freedman et al. but in some discrepancy with other recent determinations based on blue supergiant spectroscopy and an O-type eclipsing binary which yielded lower reddening values. Our derived M33 distance modulus is extremely insensitive to the adopted reddening law. We show that the possible effects of metallicity and crowding on our present distance determination are both at the 1%-2% level and therefore minor contributors to the total uncertainty of our distance result for M33.

  1. Infrared photometry of the black hole candidate Sagittarius A*

    NASA Technical Reports Server (NTRS)

    Close, Laird M.; Mccarthy, Donald W. JR.; Melia, Fulvio

    1995-01-01

    An infrared source has been imaged within 0.2 +/- 0.3 arcseconds of the unique Galactic center radio source Sgr A* High angular resolution (averaged value of the Full Width at Half Maximum (FWHM) approximately 0.55 arcseconds) was achieved by rapid (approximately 50 Hz) real-time images motion compensation. The source's near-infrared magnitudes (K = 12.1 +/- 0.3, H = 13.7 +/- 0.3, and J = 16.6 +/- 0.4) are consistent with a hot object reddened by the local extinction A(sub v) approximately 27). At the 3 sigma level of confidence, a time series of 80 images limits the source variability to less than 50% on timescales from 3 to 30 minutes. The photometry is consistent with the emission from a simple accretion disk model for a approximately 1 x 10(exp 6) solar mass black hole. However, the fluxes are also consistent with a hot luminous (L approximately 10(exp 3.5) to 10(exp 4-6) solar luminosity) central cluster star positionally coincident with Sgr A*.

  2. High Speed Photometry and Spectroscopy of Novae at Quiescence

    NASA Astrophysics Data System (ADS)

    Egan, J. M.; Woudt, P. A.; Warner, B.; Williams, R. E.; Steeghs, D. T. H.; Ribeiro, V. A. R. M.

    2014-12-01

    We present spectroscopy of Nova Velorum 1999 (V382 Vel) and Nova Sagittarii 1936c (V630 Sgr) obtained with the Southern African Large Telescope in May and July 2012 as part of our ongoing observing campaign of old novae. The SALT spectrum of V382 Vel is dominated by broad Hα emission associated with the nova shell. The other Balmer lines in the spectrum are narrower and single-peaked, with Hβ at similar line strength as He II 4686Å. The SALT spectrum of V630 Sgr is dominated by He II 4686Å, emission lines are double-peaked (except the lines of the He II Pickering series) and show clear variations in multiple spectra obtained over one-quarter of the binary orbit. Additional high speed photometry of V382 Vel has been obtained in 2012 using the new SHOC photometer of the South African Astronomical Observatory. It shows the emergence of large amplitude quasi-periodic variability with periodicities around ˜ 30 minutes, not seen previously.

  3. Analysis of RGU Photometry in Selected Area 51

    NASA Astrophysics Data System (ADS)

    Bilir, S.; Karaali, S.; Buser, R.

    2004-09-01

    A low-latitude anticenter field (l=189 °, b=+21 °) is investigated by using the full calibration tools of RGU photometry. The observed RGU data are reduced to the standard system and the separation of dwarfs and evolved stars is carried out by an empirical method. Stars are categorized into three metallicity classes, i.e. -0.25<[M/H]≤+0.50, $-1.00<[M/H]≤-0.25, and [M/H]≤-1.00 dex, and their absolute magnitudes are determined by the corresponding color-magnitude diagrams. The unusually large scattering in the two-color diagrams is reduced by excluding 153 extra-galactic objects, identifying them compared with the charts of Basel Astronomical Institute and University of Minnesota, and by the criterion and algorithm of Gaidos et al. [1]. The local logarithmic space density for giants, D*(0)=6.75, lies within the local densities of Gliese and Gliese & Jahreiss. The local luminosity function in our work for the absolute magnitude interval 3

  4. NEOWISE STUDIES OF ASTEROIDS WITH SLOAN PHOTOMETRY: PRELIMINARY RESULTS

    SciTech Connect

    Mainzer, A.; Masiero, J.; Bauer, J.; Hand, E.; Grav, T.; Mo, W.; Tholen, D. J.; McMillan, R. S.; Maleszewski, C.; Wright, E.; Watkins, J.; Spahr, T.; Cutri, R. M.; Walker, R.

    2012-01-20

    We have combined the NEOWISE and Sloan Digital Sky Survey data to study the albedos of 24,353 asteroids with candidate taxonomic classifications derived using Sloan photometry. We find a wide range of moderate to high albedos for candidate S-type asteroids that are analogous to the S complex defined by previous spectrophotometrically based taxonomic systems. The candidate C-type asteroids, while generally very dark, have a tail of higher albedos that overlaps the S types. The albedo distribution for asteroids with a photometrically derived Q classification is extremely similar to those of the S types. Asteroids with similar colors to (4) Vesta have higher albedos than the S types, and most have orbital elements similar to known Vesta family members. Finally, we show that the relative reflectance at 3.4 and 4.6 {mu}m is higher for D-type asteroids and suggest that their red visible and near-infrared spectral slope extends out to these wavelengths. Understanding the relationship between size, albedo, and taxonomic classification is complicated by the fact that the objects with classifications were selected from the visible/near-infrared Sloan Moving Object Catalog, which is biased against fainter asteroids, including those with lower albedos.

  5. GASPS Photometry of the Tucana-Horologium Association

    NASA Technical Reports Server (NTRS)

    Roberge, Donaldson J.; Roberge, Aki

    2010-01-01

    The GASPS Open Time Key Programme on Herschel represents a new opportunity to sensitively probe protoplanetary and debris disks at far-IR wavelengths. We present preliminary PACS 70 and 160 micron photometry of eighteen stars in the 30 Myr-old Tucana-Horologium association. Of these eighteen, eight were detected in the 70 micron band. Four of these eight were also detected in the 160 micron band. We constructed SEDs for these systems using optical data from Hipparcos (B and V), near-IR data from 2MASS (J, H, and K), mid-IR data from IRAS and Spitzer MIPS (12 and 24 microns, respectively), and the new far-IR data from PACS. For the stars showing IR excess emission, we fit simple single-temperature blackbody curves to the IR excess in order to determine the rough dust abundances and temperatures. Dust observations at these wavelengths will also be important for comparison with upcoming Herschel PACS spectra that will search for gas in the disks. Our goal is to determine or limit the ever-allusive gas-to-dust ratio for these disk systems.

  6. Multicolor NTT Photometry of the Anomalous Globular Cluster NGC 288

    NASA Astrophysics Data System (ADS)

    Alcaino, Gonzalo; Liller, William; Alvarado, Franklin

    1997-12-01

    We present UBV photometry of 2494 stars in a 38 arcmin square field in the anomalous high latitude globular cluster NGC 288 observed with a CCD camera and the 3.5 m NTT at ESO/La Silla. Our results can be summarized as follows: VTO=18.90±0.l4, and turnoff colors at (B-V)TO=0.46±0.05, (U - B)TO= -0.02±0.05 and independently (U - V)TO=0.45±0.07 (estimated external uncertainties). By fitting the resulting B - V ridge line to the theoretical isochrones of Bergbusch & VandenBerg (1992, ApJS, 81, 163) with [Fe/H]=-1.26, Y=0.2358, and [O/Fe]=+0.55, we derive the following values: the apparent distance modulus, (m - M)V = 14.85±0.10 and the interstellar reddening E(B - V) =0.04±0.02, and an age of 14±2 Gyr. We note the presence of approximately 17 blue stragglers, 4 hot faint BHB stars, and 5 faint possibly variable stars.

  7. A Search for Ringed Exoplanets Using Kepler Photometry

    NASA Astrophysics Data System (ADS)

    Heising, Matthew Z.; Marcy, Geoffrey W.; Schlichting, Hilke E.

    2015-11-01

    Models are developed to simulate light curves of stars dimmed by transiting exoplanets with and without rings. These models are then applied to Kepler photometry to search for planetary rings in a sample of 21 exoplanets, mostly hot Jupiters, chosen to offer the best observational opportunity for discovering potential rings. We also examine what kinds of rings might be expected for these planets, in terms of both size and orientation, based on arguments involving the host planet’s equilibrium temperature, its likely obliquities, and the formation and stability of possible ring systems. Finding no evidence for rings, for each of the 21 studied planets it is determined on an observational basis which potential rings can be rejected out of a representative set of fiducial rings, varying in both size and orientation. For 12 of the 21 planets, we determined that Saturn-like rings could be ruled out for at least certain orientations. Additionally, the detectability of rings is studied, and it is found that ringed planets with small obliquities (roughly 5°-10°) can yield large signals, which is encouraging for future work, since such small obliquities are expected for hot Jupiters.

  8. Photon counting and fast photometry with L3 CCDs

    NASA Astrophysics Data System (ADS)

    Tulloch, Simon M.

    2004-09-01

    The new L3 Technology CCDs from E2V allow detector read noise to be decoupled from readout speed. If operated at sufficiently high gain, the read noise drops to sub-electron levels and photon counting becomes possible. At ING we have incorporated CCD60 , CCD87 and CCD97 L3 detectors into cryogenic cameras coupled to SDSU controllers for a variety of tests both in the lab and on-sky using the 4.2m William Herschel Telescope. These detectors have been operated in proportional and photon-counting mode using an in-house Linux based DAS. We have gained a number of insights into photon counting optimisation, how to cope with the effects of the L3 pipeline delay and the reduction of internal device-generated spurious charge. We have also discovered a statistical method for determining the gain of an L3 system from pulse height analysis of the individual photon events. Our on-sky test program has consisted to date of high frame rate photometry of the Crab Nebula Pulsar.

  9. Performance of Electroluminescent Flats for Precision Light Curve Photometry

    NASA Astrophysics Data System (ADS)

    Avril, Ryan L.; Oberst, T. E.

    2014-01-01

    We measure of the quality of flat field frames (flats) taken using an electroluminescent (EL) panel versus both dome and sky flats for purposes of calibrating visual CCD images. Classic dome and sky flats can both suffer from overall gradients and local irregularities. EL panel flats have recently grown in popularity as a third alternative, based partly on their potential to be free of such defects. We assess the flats based on their contributions to the RMS noise of long-duration light curves constructed via differential aperture photometry. The noise levels explored range from ~ 1 - few mmag, as needed for the ground-based detection of transiting planets. The target and reference stars are deliberately permitted to drift across the CCD in order to probe pixel-to-pixel variations. Both the filter and focus are varied during the tests - the former to probe color variation in the flats, and the latter because defocusing tends to average out pixel-to-pixel variations that the flats are intended to remove. All tests were performed at the Westminster College Observatory (WCO), which belongs to the Kilodegree Extremely Little Telescope (KELT)-North follow-up network.

  10. High-speed ultraviolet photometry of HD 60435

    NASA Technical Reports Server (NTRS)

    Taylor, M.; Nelson, M. J.; Bless, R. C.; Dolan, J. F.; Elliot, J. L.; Percival, J. W.; Robinson, E. L.; Van Citters, G. W.

    1993-01-01

    We present the first high-speed ultraviolet photometry of an oscillating Ap star, HD 60435. After removing known orbital effects related to the Hubble Space Telescope, we confirm the presence of a strong pulsation period at a frequency of 123.70 cycles per day. In addition, we find significant amplitude modulation of this frequency that we suggest could be the result of beating of multiple periodicities. In this context, we suggest evidence for the presence of four additional frequencies at nu = 120.56, 126.55, 149.49, and 221.03 cycles per day. Three of these frequencies correspond well to frequencies detected in optical observations of HD 60435. The fourth, at 149.49 cycles per day, if real, is a potentially new pulsation mode that has not been detected in ground-based observations of this star. The amplitude of the 123 cycles per day pulsation is significantly larger in the ultraviolet than it is in the blue.

  11. High Precision Photometry of Bright Transiting Exoplanet Hosts

    NASA Astrophysics Data System (ADS)

    Wilson, Maurice; Eastman, Jason; Johnson, John A.

    2016-01-01

    Within the past two decades, the successful search for exoplanets and the characterization of their physical properties have shown the immense progress that has been made towards finding planets with characteristics similar to Earth. For most exoplanets with a radius about the size of Earth, evaluating their physical properties, such as the mass, radius and equilibrium temperature, cannot be determined with satisfactory precision. The MINiature Exoplanet Radial Velocity Array (MINERVA) was recently built to obtain spectroscopic and photometric measurements to find, confirm, and characterize Earth-like exoplanets. MINERVA's spectroscopic survey targets the brightest, nearby stars which are well-suited to the array's capabilities, while its primary photometric goal is to search for transits around these bright targets. Typically, it is difficult to find satisfactory comparison stars within a telescope's field of view when the primary target is very bright. This issue is resolved by using one of MINERVA's telescopes to observe the primary bright star while the other telescopes observe a distinct field of view that contains satisfactory bright comparison stars. We describe the code used to identify nearby comparison stars, schedule the four telescopes, produce differential photometry from multiple telescopes, and show the first results from this effort.This work has been funded by the Ronald E. McNair Post-Baccalaureate Achievement Program, the ERAU Honors Program, the ERAU Undergraduate Research Spark Fund, and the Banneker Institute at the Harvard-Smithsonian Center for Astrophysics.

  12. Satellite Characterization with uvbyCaH? Photometry

    NASA Astrophysics Data System (ADS)

    Hamilton, N.

    A satellite's spectrum has two contributions: reflected sunlight and its own blackbody radiation. The extended Strömgren system, uvbyH?Ca, is proposed as a self-calibrating method of subtracting out the sunlight. While the blackbody radiation contribution will be weak, it will not have the H? and Ca II H and K absorption features. It is argued here that the signal-to-noise ration of the blackbody radiation to the solar radiation may be detectable, and that information used for satellite characterization. The uvby bands will characterize the reflected sunlight and that model can be extended to the standard profile of the H? and Ca II H and K absorption lines. Any excess radiation in the absorption lines could be from the blackbody emission of the satellite. This proposed method is suited for the Haleakala 3.67m telescope since multiple coudé feeds can be used for simultaneous narrow-band photometry at various altitudes of observation. Calibration stars in this system are available, but not needed during the observation. The relative strength of the blackbody emission to the sunlight will depend on unique features of the satellite. Models of blackbody radiation detection will be presented.

  13. RELATIVE PHOTOMETRY OF HAT-P-1b OCCULTATIONS

    SciTech Connect

    Beky, Bence; Holman, Matthew J.; Noyes, Robert W.; Sasselov, Dimitar D.; Gilliland, Ronald L.; Bakos, Gaspar A.; Winn, Joshua N.

    2013-06-01

    We present Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph observations of two occultations of the transiting exoplanet HAT-P-1b. By measuring the planet to star flux ratio near opposition, we constrain the geometric albedo of the planet, which is strongly linked to its atmospheric temperature gradient. An advantage of HAT-P-1 as a target is its binary companion ADS 16402 A, which provides an excellent photometric reference, simplifying the usual steps in removing instrumental artifacts from HST time-series photometry. We find that without this reference star, we would need to detrend the lightcurve with the time of the exposures as well as the first three powers of HST orbital phase, and this would introduce a strong bias in the results for the albedo. However, with this reference star, we only need to detrend the data with the time of the exposures to achieve the same per-point scatter, therefore we can avoid most of the bias associated with detrending. Our final result is a 2{sigma} upper limit of 0.64 for the geometric albedo of HAT-P-1b between 577 and 947 nm.

  14. Stromgren $u$ Photometry of CH Cygni in 1995 and 1996

    NASA Astrophysics Data System (ADS)

    Rodgers, B.; Hoard, D. W.; Burdullis, T.; Machado-Pelaez, L.; O'Toole, M.; Reed, S.

    1997-10-01

    Rapid time-resolution, Stromgren u-band photometry of CH cygni shows a marked decrease in quasi-periodic, short time scale ( ~ 2000--3000 s) variability between 1995 August and 1996 June. In 1995, we detected variability of ~ 0.3--0.4 mag with periods of ~2200 s and ~2700 s, which are remarkably similar to periods reported by Hoard (1993) from similar u-band measurements of CH Cyg in 1992. In contrast, during a number of nights in 1996 the u magnitude was roughly constant within 0.1 mag, and the light curves showed no evidence of rapid variability. The average u magnitude of CH Cyg decreased by ~ 0.9 mag between 1995 and 1996, suggesting a common source for the quasi-periodic variability and the u-band luminosity, namely the hot component in the interacting binary. We discuss several possible explanations for this variability, including the spin of an accreting, magnetic white dwarf (as in the intermediate polar class of cataclysmic variables) and the reprocessing of accretion-induced radiation from the white dwarf in circumstellar material. (SECTION: Stars)

  15. VizieR Online Data Catalog: CCD UBVI photometry of NGC 6791 (Kaluzny+, 1995)

    NASA Astrophysics Data System (ADS)

    Kaluzny, J.; Rucinski, S. M.

    1995-06-01

    Three new photometric CCD-based datasets are presented for NGC 6791. They consist of deep UBV photometry (to Vlim=24, Blim=24, Ulim=23) of the central parts of the cluster and of selected fields around it, and of relatively shallower UBVI photometry for the whole cluster (23'x23'). The data have been used to discuss the reddening, metallicity and age of NGC 6791. (2 data files).

  16. VizieR Online Data Catalog: WASP-104b and WASP-106b photometry (Smith+, 2014)

    NASA Astrophysics Data System (ADS)

    Smith, A. M. S.; Anderson, D. R.; Armstrong, D. J.; Barros, S. C. C.; Bonomo, A. S.; Bouchy, F.; Brown, D. J. A.; Collier, Cameron A.; Delrez, L.; Faedi, F.; Gillon, M.; Gomez Maqueo Chew, Y.; Hebrard, G.; Jehin, E.; Lendl, M.; Louden, T. M.; Maxted, P. F. L.; Montagnier, G.; Neveu-Vanmalle, M.; Osborn, H. P.; Pepe, F.; Pollacco, D.; Queloz, D.; Rostron, J. W.; Segransan, D.; Smalley, B.; Triaud, A. H. M. J.; Turner, O. D.; Udry, S.; Walker, S. R.; West, R. G.; Wheatley, P. J.

    2014-09-01

    The stars WASP-104 and WASP-106 were observed by SuperWASP-N from 2008 to 2011, and by WASP-South from 2009 to 2010. This differential survey photometry has been de-reddened and normalised. Further photometry was obtained using the TRAPPIST, Euler, Liverpool and Isaac Newton telescopes in 2013 and 2014. All these data are plotted in Figures 1 and 2. (1 data file).

  17. Disk-resolved photometry of Vesta and Lutetia and comparison with other asteroids

    NASA Astrophysics Data System (ADS)

    Longobardo, Andrea; Palomba, Ernesto; Ciarniello, Mauro; Tosi, Federico; De Sanctis, Maria Cristina; Capaccioni, Fabrizio; Zambon, Francesca; Ammannito, Eleonora; Filacchione, Gianrico; Raymond, Carol A.

    2016-03-01

    Photometry of asteroids gives fundamental information about their spectral and physical properties. The aim of this work is two-fold: (1) to calculate phase functions of Vesta and Lutetia in the visible spectral range; and (2) to compare photometric properties of all the asteroids visited by space missions, as inferred from disk-resolved photometry. The phase functions of Vesta and Lutetia have been retrieved by performing a statistical analysis on data provided by the VIR-Dawn and the VIRTIS-Rosetta imaging spectrometers, respectively. The approach is based on the empirical procedure defined in Longobardo et al. (Longobardo, A. et al. [2014]. Icarus 240, 20-35). The Vesta phase functions have been calculated at two wavelengths, one outside (0.75 μm) and one inside (0.95 μm) the pyroxene absorption band at 0.9 μm. The steepness of the phase function at 0.75 μm decreases from dark to bright regions, due to the increasing role of multiple scattering. Otherwise, the phase function at 0.95 μm results in uniformity across Vesta surface, since darkening agents are spectrally featureless and their influence at wavelengths inside the pyroxene absorption band is negligible. Moreover, it is, on average, steeper than the phase functions at 0.75 μm, due to the more important role of single scattering at 0.95 μm. The Lutetia phase function is instead constant across the surface due to the homogeneous spectral properties of this asteroid. The obtained photometric curves (reflectance versus phase angle) of Vesta and Lutetia have been then compared with those retrieved in previous works on asteroids visited by space missions. Differently from comparisons of disk-integrated phase functions of asteroids performed in previous works at low phase angles (lower than 25°), this work restricts to asteroid observations that are disk-resolved and occur at solar phase angles between 20° and 60°. The S-type asteroids (Gaspra, Ida, Eros and Annefrank) show similar photometric curves. The phase functions found in bright material units on Vesta are similar to those found for Steins (E-type in the Tholen taxonomy, Xe-type in the Bus one), suggesting a photometric analogy between achondritic surfaces. The latter are brighter and with a flatter phase function with respect to chondritic surfaces: we argued that this behavior is driven by optical properties of asteroid surfaces (e.g. albedo, role of multiple scattering) rather than by physical ones (e.g. grain size, roughness). Dark material units on Vesta show an intermediate behavior between achondrites and the C-type Mathilde, confirming once again that these regions are characterized by mixtures of HED and carbonaceous chondrites. While a clear anti-correlation is observed between reflectance and steepness of phase function for V, S and C asteroids, Lutetia shows an anomalous photometric behavior, presenting both a low reflectance and a flat phase curve, and hence cannot be grouped with other spectral classes here considered. This behavior is similar to some X-type asteroids ground-observed at low phase angles and is consistent with a chondritic composition of its surface.

  18. SYNMAG PHOTOMETRY: A FAST TOOL FOR CATALOG-LEVEL MATCHED COLORS OF EXTENDED SOURCES

    SciTech Connect

    Bundy, Kevin; Yasuda, Naoki; Hogg, David W.; Higgs, Tim D.; Nichol, Robert C.; Masters, Karen L.; Lang, Dustin; Wake, David A.

    2012-12-01

    Obtaining reliable, matched photometry for galaxies imaged by different observatories represents a key challenge in the era of wide-field surveys spanning more than several hundred square degrees. Methods such as flux fitting, profile fitting, and PSF homogenization followed by matched-aperture photometry are all computationally expensive. We present an alternative solution called 'synthetic aperture photometry' that exploits galaxy profile fits in one band to efficiently model the observed, point-spread-function-convolved light profile in other bands and predict the flux in arbitrarily sized apertures. Because aperture magnitudes are the most widely tabulated flux measurements in survey catalogs, producing synthetic aperture magnitudes (SYNMAGs) enables very fast matched photometry at the catalog level, without reprocessing imaging data. We make our code public and apply it to obtain matched photometry between Sloan Digital Sky Survey ugriz and UKIDSS YJHK imaging, recovering red-sequence colors and photometric redshifts with a scatter and accuracy as good as if not better than FWHM-homogenized photometry from the GAMA Survey. Finally, we list some specific measurements that upcoming surveys could make available to facilitate and ease the use of SYNMAGs.

  19. SYNMAG Photometry: A Fast Tool for Catalog-level Matched Colors of Extended Sources

    NASA Astrophysics Data System (ADS)

    Bundy, Kevin; Hogg, David W.; Higgs, Tim D.; Nichol, Robert C.; Yasuda, Naoki; Masters, Karen L.; Lang, Dustin; Wake, David A.

    2012-12-01

    Obtaining reliable, matched photometry for galaxies imaged by different observatories represents a key challenge in the era of wide-field surveys spanning more than several hundred square degrees. Methods such as flux fitting, profile fitting, and PSF homogenization followed by matched-aperture photometry are all computationally expensive. We present an alternative solution called "synthetic aperture photometry" that exploits galaxy profile fits in one band to efficiently model the observed, point-spread-function-convolved light profile in other bands and predict the flux in arbitrarily sized apertures. Because aperture magnitudes are the most widely tabulated flux measurements in survey catalogs, producing synthetic aperture magnitudes (SYNMAGs) enables very fast matched photometry at the catalog level, without reprocessing imaging data. We make our code public and apply it to obtain matched photometry between Sloan Digital Sky Survey ugriz and UKIDSS YJHK imaging, recovering red-sequence colors and photometric redshifts with a scatter and accuracy as good as if not better than FWHM-homogenized photometry from the GAMA Survey. Finally, we list some specific measurements that upcoming surveys could make available to facilitate and ease the use of SYNMAGs.

  20. Star clusters of the Large Magellanic Cloud - CCD photometry of NGC 1831

    NASA Astrophysics Data System (ADS)

    Vallenari, A.; Chiosi, C.; Bertelli, G.; Meylan, G.; Ortolani, S.

    1992-09-01

    The Johnson BV-CCD photometry of the LMC cluster NGC 1831 and of a companion field is presented. These data are used to construct a CMD of the cluster corrected for photometric incompleteness and contamination by field stars, and a luminosity function of the main-sequence stars complete down to V = 20.5. The surface brightness profile of NGC 1831 can be satisfactorily fitted with a King-Michie model with isotropic velocity dispersion and Salpeter initial mass function (x - 1.35) characterized by concentration log(rt/rc) = 1.2, core radius of 11.8 arcsec, and tidal radius of 187.0 arcsec. The photometric quality of the data is assessed by means of various crowding experiments in order to provide the completeness factors per magnitude bin for the B and V passbands, and to derive expressions for the photometric errors as a function of B and V magnitudes. From the detailed morphology of the CMD, and in particular the existence of stars in the Hertzsprung gap, it is suggested that a substantial fraction of unresolved stars is likely present.

  1. Multicolour time series photometry of four short-period weak-lined T Tauri stars

    NASA Astrophysics Data System (ADS)

    Koen, C.

    2015-05-01

    The paper describes continuous photometric monitoring of four pre-main-sequence stars, probable members of young stellar associations. Measurements, covering at least four nights per star, were obtained by cycling through several filters. The data could be used to choose between aliases of rotation periods quoted in the literature. As expected, the amplitudes of sinusoidal variations decline with increasing wavelength, mildly enough to indicate the presence of coolspots on the stellar surfaces. Variability amplitudes can dwindle from a 0.1 mag level to virtually zero on a time-scale of one or two days. A flare observed in CD-36 3202 is discussed in some detail, and a useful mathematical model for its shape is introduced. It is demonstrated that accurate colour indices (σ < 5-6 mmag, typically) can be derived from the photometry. The magnitude variations as measured through different filters are linearly related. This is exploited to calculate spot temperatures (800-1150 K below photospheric for the different stars) and the ranges of variation of the spot filling factors (roughly 10-20 per cent). The available All Sky Automated Survey measurements of the stars are analysed, and it is concluded that there is good evidence for differential rotation in all four stars.

  2. Photometry from voyager 2: initial results from the uranian atmosphere, satellites, and rings.

    PubMed

    Lane, A L; Hord, C W; West, R A; Esposito, L W; Simmons, K E; Nelson, R M; Wallis, B D; Buratti, B J; Horn, L J; Graps, A L; Pryor, W R

    1986-07-01

    The Voyager 2 photopolarimeter successfully completed the Uranus encounter, acquiring new data on the planet's atmosphere, its principal satellites, and its ring system. Spatially resolved photometry of the atmosphere at 0.27 micrometer shows no enhancement in absorption toward the pole, unlike the case for Jupiter and Saturn. Stellar occultation measurements indicate the temperature at the 1-millibar level over the north pole is near 90 kelvins. The geometric albedos of the five large satellites of Uranus were measured at 0.27 and 0.75 micrometer and indicate the presence of low albedo, spetrally flat absorbing material. Titania seems to have a fluffy surface, as indicated by its phase curve. The nine ground-based rings were detected, and their internal structure, optical depths, and positions were determined. The sharp edges of the in ring made it possible to measure its edge thickness (less than 150 meters) and particle sizes (less than 30 meters); little or no dust was detcted. New narrow rings and partial rings (arcs) were measured, and the narrow component of the eta ring was found to be discontinuous. PMID:17812890

  3. Imaging Spotted Stars with Simultaneous Interferometry, Spectroscopy, and Photometry

    NASA Astrophysics Data System (ADS)

    Roettenbacher, Rachael; Monnier, John; Korhonen, Heidi; Harmon, Robert; Henry, Gregory W.; Fekel, Francis C.; Williamson, Michael; Latham, David

    2015-08-01

    Harnessing the sub-milliarcsecond resolving capabilities of the world's largest infrared interferometer, the Center for High Angular Resolution Astronomy (CHARA) Array, we combine light from all six telescopes with the Michigan Infrared Combiner (MIRC) to directly image the spotted stellar surfaces of the giant primary stars of RS CVn binary systems. In the first study of its kind, we compare these unprecedented interferometric (aperture synthesis) images of stars with simultaneous Doppler and light-curve inversion images to verify the methods and understand their limitations. Using the latitude information we obtain from the Doppler and aperture synthesis images, we investigate degeneracies across hemispheres and the latitude dependence of magnetic field structures. Additionally, we have made the first detections of the systems' faint companions (H-band flux ratios >250:1), detected ellipsoidal variations, and measured gravity darkening. Together these results affect previous analyses of starspot location (e.g. active longitudes), evolution, and differential rotation. Whether or not current solar dynamos can accurately predict the properties of the young, active Sun is unclear; our detailed studies of active, cool giants with rapid rotation and large starspots may help broaden and guide extensions of dynamo theory.

  4. Surface composition of Pluto

    NASA Technical Reports Server (NTRS)

    Lebofsky, L. A.; Lebofsky, M. J.; Rieke, G. H.

    1979-01-01

    Broadband (J, H, K and L) and narrowband (1.5- to 3.7-micron) infrared photometry of Pluto has been conducted in order to check previous ambiguous observations of methane frost on the planet's surface. In detail, the match between a laboratory spectrum of methane frost and the observed spectrum of Pluto is not good. Nevertheless, the photometric observations suggest the presence of methane in some form.

  5. Steric factors affecting the discrimination of isomeric and structurally related olefin gases and vapors with a reagent-coated surface acoustic wave sensor.

    PubMed

    Zellers, E T; Zhang, G Z

    1992-06-01

    An investigation of steric factors affecting the olefin-olefin selectivity of a surface acoustic wave (SAW) sensor coated with reagents of the general formula trans-PtCl2(ethylene)-(substituted-pyridine) is described. Detection is based on the mass increase accompanying replacement of ethylene by other gas-phase olefins to form the corresponding olefin-substituted products. Selectivity depends on the relative reaction rates of the different olefins. Within series of structurally similar butenes, acrylates, and aromatic olefins, unusually high selectivity is observed for the less hindered olefins and complete discrimination of isomers is achieved in certain cases. Replacing pyridine by 2-methylpyridine and 2,6-dimethylpyridine in the reagent complex progressively reduces the sensor response. Sensitivities increase with increasing temperature and limits of detection ranging from about 2 to 70 micrograms/L are achieved with modest heating (30-40 degrees C) using a 30-MHz SAW oscillator. Initial results with a 52-MHz sensor shows a 3.4-fold increase in sensitivity compared to the 30-MHz sensor in rough agreement with theory. PMID:1621995

  6. Flight Investigation on a Fighter-type Airplane of Factors which Affect the Loads and Load Distributions on the Vertical Tail Surfaces During Rudder Kicks and Fishtails

    NASA Technical Reports Server (NTRS)

    Boshar, John

    1947-01-01

    Results are presented of a flight investigation conducted on a fighter-type airplane to determine the factors which affect the loads and load distributions on the vertical tail surfaces in maneuvers. An analysis is made of the data obtained in steady flight, rudder kicks, and fishtail maneuvers. For the rudder kicks, the significant loads were the "deflection load" resulting from an abrupt control deflection and the "dynamic load" consisting of a load corresponding to the new static equilibrium condition for the rudder deflected plus a load due to a transient overshoot. The minimum time to reach the maximum control deflection attainable by the pilot in any flight condition was found to be a constant. In the fishtail maneuvers, it was found that the pilot tends to deflect the rudder in phase with the natural frequency of the airplane. The maximum loads measured in fishtails were of the same order of magnitude as those from a rudder kick in which the rudder is returned to zero at the time of maximum sideslip.

  7. SECONDARY ECLIPSE PHOTOMETRY OF WASP-4b WITH WARM SPITZER

    SciTech Connect

    Beerer, Ingrid M.; Knutson, Heather A.; Burrows, Adam; Fortney, Jonathan J.; Laughlin, Gregory; Agol, Eric; Cowan, Nicolas B.; Charbonneau, David; Desert, Jean-Michel; Deming, Drake; Langton, Jonathan; Lewis, Nikole K.; Showman, Adam P.

    2011-01-20

    We present photometry of the giant extrasolar planet WASP-4b at 3.6 and 4.5 {mu}m taken with the Infrared Array Camera on board the Spitzer Space Telescope as part of Spitzer's extended warm mission. We find secondary eclipse depths of 0.319% {+-} 0.031% and 0.343% {+-} 0.027% for the 3.6 and 4.5 {mu}m bands, respectively, and show model emission spectra and pressure-temperature profiles for the planetary atmosphere. These eclipse depths are well fit by model emission spectra with water and other molecules in absorption, similar to those used for TrES-3 and HD 189733b. Depending on our choice of model, these results indicate that this planet has either a weak dayside temperature inversion or no inversion at all. The absence of a strong thermal inversion on this highly irradiated planet is contrary to the idea that highly irradiated planets are expected to have inversions, perhaps due the presence of an unknown absorber in the upper atmosphere. This result might be explained by the modestly enhanced activity level of WASP-4b's G7V host star, which could increase the amount of UV flux received by the planet, therefore reducing the abundance of the unknown stratospheric absorber in the planetary atmosphere as suggested in Knutson et al. We also find no evidence for an offset in the timing of the secondary eclipse and place a 2{sigma} upper limit on |ecos {omega}| of 0.0024, which constrains the range of tidal heating models that could explain this planet's inflated radius.

  8. Multicolor Photometry of the Type II Cepheid Prototype W Virginis

    NASA Astrophysics Data System (ADS)

    Templeton, M. R.; Henden, A. A.

    2007-11-01

    We present the results of recent long-term BVRCIC photometric monitoring of the type II Cepheid prototype W Virginis. These new observations, made during the 2006 and 2007 observing season, represent the longest homogeneous, multicolor light curve of W Vir to date. The BVRCIC light and color curves show conclusively that W Vir exhibits modest but detectable cycle-to-cycle variations, the cause of which appears to be multiperiodicity rather than nonlinearity. We combined our V-band data with the five available years of ASAS-3 V-band photometry to obtain a 6.5 yr light curve that we then analyzed to obtain the pulsation spectrum of W Vir. We find a best-fit period P0 = 17.27134 days; along with this period and the integer-ratio harmonics P0/2 through P0/5 inclusive, we clearly detect two additional periods, P1 and Plow, that are close to but not exactly 2P0/3 and 2P0, respectively. The former, P1 = 11.52562 days, we interpret to be the first overtone mode; the latter, Plow = 34.59760 days, is close to the beat period of (P - P)-1, as well as to the value of 2P0. We interpret the previously reported but thus far unconfirmed descriptions of alternating minima as manifestations of this multiperiodicity. Finally, we use the period derived from the V-band light curve to define a new ephemeris: HJDmax = 2,452,758.172 + 17.27134E. We compiled an (O - C) diagram spanning 75 yr from 1932 to 2007 using a variety of published photometric data and visual observations from the American Association of Variable Star Observers and derived a period-change term for the ephemeris equal to -9.9 × 10-7E2, indicating a period decrease.

  9. Precision Photometry to Study the Nature of Dark Energy

    SciTech Connect

    Lorenzon, Wolfgang; Schubnell, Michael

    2011-01-30

    Over the past decade scientists have collected convincing evidence that the expansion of the universe is accelerating, leading to the conclusion that the content of our universe is dominated by a mysterious 'dark energy'. The fact that present theory cannot account for the dark energy has made the determination of the nature of dark energy central to the field of high energy physics. It is expected that nothing short of a revolution in our understanding of the fundamental laws of physics is required to fully understand the accelerating universe. Discovering the nature of dark energy is a very difficult task, and requires experiments that employ a combination of different observational techniques, such as type-Ia supernovae, gravitational weak lensing surveys, galaxy and galaxy cluster surveys, and baryon acoustic oscillations. A critical component of any approach to understanding the nature of dark energy is precision photometry. This report addresses just that. Most dark energy missions will require photometric calibration over a wide range of intensities using standardized stars and internal reference sources. All of the techniques proposed for these missions rely on a complete understanding of the linearity of the detectors. The technical report focuses on the investigation and characterization of 'reciprocity failure', a newly discovered count-rate dependent nonlinearity in the NICMOS cameras on the Hubble Space Telescope. In order to quantify reciprocity failure for modern astronomical detectors, we built a dedicated reciprocity test setup that produced a known amount of light on a detector, and to measured its response as a function of light intensity and wavelength.

  10. Just the Photometry: Constraining exoplanet orbits by measuring stellar densities

    NASA Astrophysics Data System (ADS)

    Sliski, David; Kipping, D. M.

    2014-01-01

    One unique trick in toolkit of astronomers studying transiting exoplanets, is that the mean stellar density may be determined using the shape of the light curve, under various idealized assumptions such as a circular orbit and the target star is unblended. “Asterodensity profiling” seeks to exploit this trick by comparing the light curve derived stellar density to that from some independent measurement. Any difference between the two measures indicates that one or more of the idealized assumptions are invalid. Therefore, the major challenge with single-planet systems (so-called “single-body asterodensity profiling” or SAP) is distinguishing whether the difference is due to a blend, orbital eccentricity or some combination. By careful consideration of the input priors, utilizing constraints from secondary eclipses and a Bayesian analysis of the system in question, the problem is tractable though, offering the chance to determine the underlying eccentricity distribution of exoplanets and even aid in validating planet candidates through blend analysis. In this talk, I will discuss single-body asterodensity profiling (SAP) for targets with asteroseismologically determined stellar densities, which is generally considered a gold-standard measure. We have investigated several targets with the largest apparent discrepancies between the transit-derived stellar density and that from asteroseismology. By independently detrending and fitting the transit light curves, we have calculated a revised value of this crucial ratio, with various priors tried. I will present the current results our work and discuss implications for the eccentricity and blend validation of these studied systems. I will finish by exploring the exciting potential of this technique in the TESS-era, where the fact our technique requires bright-star photometry alone, opens the door to constraints for hundreds/thousands of objects.

  11. VizieR Online Data Catalog: Photometry and motions in Arches and Quintuplet (Stolte+, 2015)

    NASA Astrophysics Data System (ADS)

    Stolte, A.; Hussmann, B.; Olczak, C.; Brandner, W.; Habibi, M.; Ghez, A. M.; Morris, M. R.; Lu, J., R.; Clarkson, W., I.; Anderson, J.

    2015-02-01

    Two to three epochs of photometry and astrometric imaging were obtained in the Arches and Quintuplet clusters with the VLT/NAOS-CONICA instrument from 2002 to 2012, covering timebaselines from 3 to 5 years in each of five fields per cluster. Astrometry and proper motions were derived from Ks imaging. The combination with HST/WFC3 F127M and F153M imaging provided infrared colours, and NACO L' observations were used to derive infrared excess emission. The spatial resolution of all NAOS-CONICA observations was 27.1-milliarcseconds/pixel and 130mas/pixel for all WFC3 images. The catalogue provides all epochs of Ks photometry and proper motions for stars brighter than Ks=17.5mag. Proper motions are derived as the positional difference between two astrometric epochs. HST/WFC3 F127M and F153M photometry was converted to standard JH photometry with colour equations provided in the paper. L' photometry was referenced to the Spitzer/GLIMPSE survey with uncertain zeropoints due to the large differences in spatial resolution, and absolute values should be treated with care, while relative photometry is robust. Membership indicators are given as follows: 1: likely cluster member, 0: likely non-member, -1: unknown membership, -99: two epoch measurements could not be obtained. For Quintuplet cluster (tablee1.dat), an indication of cluster membership is given as a formal probability in Field 2-5, where stars with pclus>0.4 are likely member candidates. A value of -99.0 indicates that the corresponding photometry or astrometry could not be obtained. (2 data files).

  12. Documentation for the machine-readable version of the ANS Ultraviolet Photometry Catalogue of Point Sources (Wesselius et al 1982)

    NASA Technical Reports Server (NTRS)

    Warren, W. H., Jr.

    1984-01-01

    The machine-readable version of the Astronomical Netherlands Satellite ultraviolet photometry catalog is described in detail, with a byte-by-byte format description and characteristics of the data file given. The catalog is a compilation of ultraviolet photometry in five bands, within the wavelength range 155 nm to 330 nm, for 3573 mostly stellar objects. Additional cross reference data (object identification, UBV photometry and MK spectral types) are included in the catalog.

  13. Is increasing industrialization affecting remote ecosystem health in the South Americas? Insights from ocean surface water measurements of As, Sb and Pb from a GEOTRACES transect

    NASA Astrophysics Data System (ADS)

    Weiss, Dominik; Salaun, Pascal; Van den Berg, Stan; Bi, Zaoshun

    2014-05-01

    Continued industrial development of the South Americas with increasing atmospheric emission of toxic trace metals has lead to a growing concern about possible effects on pristine ecosystem health. Concentration measurements of trace metals in ocean surface waters in the North Atlantic have successfully revealed the global extent of atmospheric pollution in the Northern Hemisphere during economical growth in the USA and Europe, suggesting a similar approach can be applied to the Southern Hemisphere. To this end, we determined concentrations of lead (Pb), antimony (Sb) and arsenic (As) using voltammetry in surface water samples of the South Atlantic Ocean collected during the third leg of the GEOTRACES West Atlantic Cruise. These elements are volatile and therefore most likely suitable tracer elements of industrial emissions from South America. The samples were not filtered and the solutions were acidified and UV digested. Total concentrations of Pb were detected. Detected As levels correspond to the sum of inorganic species (AsIII + AsV) plus the mono methyl arsenic acid (MMA) while the dimethyl arsenic acid (DMA) is not detected in such conditions. For Sb, detected levels correspond at least to the sum of inorganic fractions (SbIII + SbV). The measured concentrations for Pb varied from 6 to 23 pM. Concentrations were highest at -35° latitude and lowest at -40° and -50° latitude. We found a decreasing trend from about -35° latitude southwards. The average concentrations of As was 20 nM and of Sb 1.2 nM. Arsenic showed a more significant north to south trend than Sb. Arsenic concentration was highest at -23 ° latitude (21 nM) and the lowest at -43 ° latitude (17.7 nM). Antimony concentration was highest at -31 ° latitude (1.5 nM) and lowest at -35 ° latitude (1.0 nM). Our preliminary data suggests that the major industrial centres in Brazil (i.e., Sao Paolo, Rio de Janeiro) and Argentina (i.e., Buenos Aires) affect atmospheric metal fluxes to remote environments. The concentrations, however, are not as high as determined in the Northern Hemisphere, suggesting a less drastic impact. That is also reflected in air quality data from the major cities.

  14. Comparative evaluation of microshear bond strength of the caries-affected dentinal surface treated with conventional method and chemomechanical method (papain)

    PubMed Central

    Chittem, Jyothi; Sajjan, Girija S.; Varma, Kanumuri Madhu

    2015-01-01

    Background: There is a growing interest in chemomechanical excavation (papain) in permanent molar teeth. There are several studies dealing with primary molar teeth. Aim: The aim of this study was to evaluate the influence of conventional method and Carie-care (chemomechanical method) on the microshear bond strength (μSBS) and the type of failure of an adhesive system to caries-affected dentin of permanent molar teeth. Materials and Methods: Twenty permanent molar teeth with carious lesions extending into the dentin were selected. Through the center of the carious lesion, teeth were sectioned mesiodistally and divided into two groups based on the method of caries excavation (conventional and chemomechanical method). The time required for the completion of excavation procedure was noted. Samples were again divided into two subgroups in each according to the method of restoration (Ketac N100 and Filtek Z350 composite). The bonded interface was subjected to μSBS testing in a universal testing machine. Fractured surfaces were examined under a stereomicroscope, and representative specimens were examined under scanning electron microscope for the type of failure. Statistical Analysis: It was achieved with unpaired t-test and Kruskal-Wallis H-test at 5% level of significance. Results: The μSBS values of Carie-care groups were similar to that of the conventional method. The μSBSs of resin composite were significantly (P < 0.001) more than that of resin glass ionomer bonded irrespective of the method of caries excavation. Conclusion: A papain-based chemomechanical agent can be used safely as a method for caries removal when employing conventional adhesive systems. PMID:26430299

  15. Surface Facial Electromyography, Skin Conductance, and Self-Reported Emotional Responses to Light- and Season-Relevant Stimuli in Seasonal Affective Disorder

    PubMed Central

    Lindsey, Kathryn Tierney; Rohan, Kelly J.; Roecklein, Kathryn A.; Mahon, Jennifer N.

    2011-01-01

    Background Learned associations between depressive behavior and environmental stimuli signaling low light availability and winter season may play a role in seasonal affective disorder (SAD). The purpose of this study was to determine whether light and season environmental cues elicit emotional responses that are distinct in individuals with SAD. Methods Twenty-four currently depressed SAD participants were compared to 24 demographically-matched controls with no depression history on emotional responses to outdoor scenes captured under two light intensity (i.e., clear, sunny vs. overcast sky) and three season (i.e., summer with green leaves, fall with autumn foliage, and winter with bare trees) conditions. Emotion measures included surface facial electromyography (EMG) activity in the corrugator supercilii and zygomaticus major muscle regions, skin conductance, and self-reported mood state on the Profile of Mood States Depression–Dejection Subscale. Results Light intensity was a more salient cue than season in determining emotional reactions among SAD participants. Relative to controls, SAD participants displayed more corrugator activity, more frequent significant skin conductance responses (SCR), greater SCR magnitude, and more self-reported depressed mood in response to overcast stimuli and less corrugator activity, lower SCR magnitude, and less self-reported depressed mood in response to sunny stimuli. Limitations Study limitations include the single, as opposed to repeated, assessment and the lack of a nonseasonal depression group. Conclusions These findings suggest that extreme emotional reactivity to light-relevant stimuli may be a correlate of winter depression; and future work should examine its potential onset or maintenance significance. PMID:21600661

  16. Photometry of supernovae in an image series: methods and application to the SuperNova Legacy Survey (SNLS)

    NASA Astrophysics Data System (ADS)

    Astier, P.; El Hage, P.; Guy, J.; Hardin, D.; Betoule, M.; Fabbro, S.; Fourmanoit, N.; Pain, R.; Regnault, N.

    2013-09-01

    Aims: We present a technique to measure lightcurves of time-variable point sources on a spatially structured background from imaging data. The technique was developed to measure lightcurves of SNLS supernovae in order to infer their distances. This photometry technique performs simultaneous point spread function (PSF) photometry at the same sky position on an image series. Methods: We describe two implementations of the method: one that resamples images before measuring fluxes, and one which does not. In both instances, we sketch the key algorithms involved and present the validation using semi-artificial sources introduced in real images in order to assess the accuracy of the supernova flux measurements relative to that of surrounding stars. We describe the methods required to anchor these PSF fluxes to calibrated aperture catalogs, in order to derive SN magnitudes. Results: We find a marginally significant bias of 2 mmag of the after-resampling method, and no bias at the mmag accuracy for the non-resampling method. Given surrounding star magnitudes, we determine the systematic uncertainty of SN magnitudes to be less than 1.5 mmag, which represents about one third of the current photometric calibration uncertainty affecting SN measurements. The SN photometry delivers several by-products: bright star PSF flux measurements which have a repeatability of about 0.6%, as for aperture measurements; we measure relative astrometric positions with a noise floor of 2.4 mas for a single-image bright star measurement; we show that in all bands of the MegaCam instrument, stars exhibit a profile linearly broadening with flux by about 0.5% over the whole brightness range. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii.

  17. Broad-band BVRI photometry of isolated spiral galaxies

    NASA Astrophysics Data System (ADS)

    Hernndez-Toledo, H. M.; Ortega-Esbr, S.

    2008-08-01

    Context: Uniform and high resolution observations in samples of isolated galaxies are required to estimate fundamental morphological and structural parameters for comparative studies of environmental effects and for confronting model predictions of galaxy evolution. A subsample of The Catalog of Isolated Galaxies (CIG), Karachentseva (1973), has been uniformly observed at San Pedro Mrtir National Observatory in Mxico and a photometric and morphological study of these galaxies has been carried out. Aims: We report multicolor broad band (BVRI) photometry for a subsample of 40 isolated spirals drawn from the CIG. Total magnitudes and colors at various circular apertures as well as a detailed morphological analysis that is extended into the NIR bands are presented. Some structural parameters are estimated from the global light distribution in the optical and NIR bands to complement our morphological analysis and several correlations between the photometric and structural parameters are explored. Emphasis was given to the detection of morphological distortions at high/low intensity levels. Methods: The observations, data reduction, and analysis are described. Morphology is reevaluated from a combination of optical logarithmically scaled R band images, filter-enhanced R band images, (B-I) color index maps, archived near IR {JHK} images from the TwoMicron Survey and optical-NIR ? and PA radial profiles after an isophotal analysis. {RGB} images from the SDSS database were retrieved when available to complement our analysis. The {CAS} structural parameters (Concentration, Asymmetry, and Clumpiness) were calculated from the images in each band. Results: The fraction of galaxies with well-identified optical/near-IR bars (SB) is 40%, while another 25% shows evidence of weak or suspected bars (SAB). The sample average value of the maximum bar ellipticity is ?_max? 0.35. 57.5% of the galaxies in the sample show rings. The {CAS} parameters change with the observed band, the morphological type and global color. We found 9 isolated galaxies with disturbed morphology. After reviewing their local number density and tidal strength parameters, we identified CIG 744 as a morphologically disturbed isolated galaxy having M_HI/LI > 1; a tentative candidate to interact with a dark gas-rich object. However, its loci in the ?0 ^I/log(M_HI/LI) diagram, suggests that CIG 744 is itself a gas-rich disturbed-isolated galaxy probably in a lengthy or ongoing process of formation, instead. Appendices A and B are only available in electronic form at http://www.aanda.org

  18. Results of CCD Transit Photometry Testing for the Kepler Mission

    NASA Astrophysics Data System (ADS)

    Koch, D.; Witteborn, F.; Dunham, E.; Jenkins, J.; Borucki, W.; Webster, L.

    1999-12-01

    Transit signals produced by Earth-size planets in orbit around solar-like stars are of the order of 8e-5 and have durations from 4 to 16 hours for planets in or near the habitable zone. A mission to search for habitable planets has been proposed (Koch, et al., 1998). At the heart of the mission is an array of CCDs used to continuously measure the relative brightness variations of 100,000 dwarf stars for transits. A testbed facility has been constructed to determine the effects of various induced noise sources on the capability of a CCD photometer to maintain an instrument relative precision of better than 1e-5. The photometry facility includes: a simulated star field with an approximate solar spectrum, fast optics to simulate the space borne telescope, a thinned back-illuminated CCD similar to those to be used on the spacecraft operating at 1 Mpix/sec read rate, and shutterless operation. The test facility is thermally and mechanically isolated. Each source of noise is introduced in a controlled fashion and evaluated. Pointing noise or changing thermal conditions in the spacecraft can cause star-image motion at the milli-pixel level. These motions are imposed by piezo-electric devices that move the photometer relative to the star field. Transit signals as small as Earth-size transits of solar-like stars are generated and measured. This is accomplished by electrical self-heating and expansion of fine wires placed across many of the star apertures. The small decrease in stellar brightness is used to demonstrate that Earth-size planets can be detected under realistic noise conditions and at the shot-noise-limited level. The effects of imposing several noise sources are shown and the resulting detectability of planets is presented. This work is supported in part by the NASA Discovery program and NASA Ames. Koch, D., Borucki, W., Webster, L., Dunham, E., Jenkins, J., Marriott, J. and Reitsema, H. SPIE Conf. on Space Telescopes and Instruments V, 3356, 599-607 (1998)

  19. High-precision ground-based photometry of exoplanets

    NASA Astrophysics Data System (ADS)

    de Mooij, Ernst J. W.; Jayawardhana, Ray

    2013-04-01

    High-precision photometry of transiting exoplanet systems has contributed significantly to our understanding of the properties of their atmospheres. The best targets are the bright exoplanet systems, for which the high number of photons allow very high signal-to-noise ratios. Most of the current instruments are not optimised for these high-precision measurements, either they have a large read-out overhead to reduce the readnoise and/or their field-of-view is limited, preventing simultaneous observations of both the target and a reference star. Recently we have proposed a new wide-field imager for the Observatoir de Mont-Megantic optimised for these bright systems (PI: Jayawardhana). The instruments has a dual beam design and a field-of-view of 17' by 17'. The cameras have a read-out time of 2 seconds, significantly reducing read-out overheads. Over the past years we have obtained significant experience with how to reach the high precision required for the characterisation of exoplanet atmospheres. Based on our experience we provide the following advice: Get the best calibrations possible. In the case of bad weather, characterise the instrument (e.g. non-linearity, dome flats, bias level), this is vital for better understanding of the science data. Observe the target for as long as possible, the out-of-transit baseline is as important as the transit/eclipse itself. A short baseline can lead to improperly corrected systematic and mis-estimation of the red-noise. Keep everything (e.g. position on detector, exposure time) as stable as possible. Take care that the defocus is not too strong. For a large defocus, the contribution of the total flux from the sky-background in the aperture could well exceed that of the target, resulting in very strict requirements on the precision at which the background is measured.

  20. Hubble Space Telescope Photometry for the Halo Stars in the Leo Elliptical NGC 3377

    NASA Astrophysics Data System (ADS)

    Harris, William E.; Harris, Gretchen L. H.; Layden, Andrew C.; Stetson, Peter B.

    2007-07-01

    We have used the ACS camera on HST to obtain (V,I) photometry for 57,000 red giant stars in the halo of the Leo elliptical NGC 3377, an intermediate-luminosity elliptical. We use this sample of stars to derive the metallicity distribution function (MDF) for its halo field stars and comment on its chemical evolution history compared with both larger and smaller E galaxies. Our ACS WFC field spans a radial range extending from 4 to 18 kpc projected distance from the center of NGC 3377 and thus covers a significant portion of this galaxy's halo. We find that the MDF is broad, reaching a peak at log(Z/Zsolar)~=-0.6, but containing virtually no stars more metal-poor than log(Z/Zsolar)=-1.5. It may, in addition, have relatively few stars more metal-rich than log(Z/Zsolar)~=-0.3, although interpretation of the high-metallicity end of the MDF is limited by photometric completeness that affects the detection of the reddest, most metal-rich stars. NGC 3377 appears to have an enrichment history intermediate between those of normal dwarf ellipticals and the much larger giants. As yet, we find no clear evidence that the halo of NGC 3377 contains a significant population of ``young'' (<3 Gyr) stars. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program 9811. Support for this work was provided in part by NASA through grant HST-GO-09811.01-A from the Space Telescope Science Institute, under NASA contract NAS 5-26555.

  1. Revisiting the photometry of (308635) 2005 YU_{55} in four colors at McDonald Observatory

    NASA Astrophysics Data System (ADS)

    Ries, J.

    2014-07-01

    We have obtained wide-field CCD images of asteroid (308635) 2005 YU_{55} during November 13-18, 2011, using the McDonald Observatory 0.76-m telescope with a Prime Focus Corrector. The field of view of this instrument is 45' by 45', which allows reliable relative photometry in spite of the substantial sky motion of the object. We planned to take exposures through the B, V, R, and I filters, and spaced the timing to evenly sample the estimated 18-hour rotational period (based on Arecibo radar observations obtained in April 2010). We have also observed Landolt photometric standards on two separate nights under very good sky conditions to calibrate the target either directly or by calibrating the reference stars imaged with the target. We hoped to obtain color indexes and see how the color affects the lightcurve. Unfortunately, due to a glitch of new software installation at that time, the filter entries in the image headers were incorrect. It was easy to correctly identify the actual filters for the Landolt fields, but we had problems separating the V, R, and I images for the actual object. We are using only the images for which the identification is unambiguous, and we have approximately 100 images in R, 80 in V, 40 in B, and 20 in I. Using the phase parameter and the rotational period determined by other studies (Hicks, et al., Warner, et al.), we attempt to reconstruct the lightcurve in V and R and look for possible phase dependence in the (V-R) color index. Although the radar data favors the 19.31-h rotational period (Busch et al.), we will also check whether our data is consistent with the shorter 16.34-h solution. The results will be presented at the meeting.

  2. Multicolor Photometry and Time-resolved Spectroscopy of Two sdBV Stars

    NASA Astrophysics Data System (ADS)

    Reed, M. D.; O'Toole, S. J.; Telting, J. H.; Østensen, R. H.; Heber, U.; Barlow, B. N.; Reichart, D. E.; Nysewander, M. C.; LaCluyze, A. P.; Ivarsen, K. M.; Haislip, J. B.; Bean, J.

    2012-03-01

    Observational mode constraints have mostly been lacking for short period pulsating sdB stars, yet such identifications are vital to constrain models. Time-resolved spectroscopy and multicolor photometry have been employed with mixed results for short-period pulsating sdB stars. Time-resolved spectroscopy has successfully measured radial velocity, temperature, and gravity variations in six pulsators, yet interpreting results is far from straightforward. Multicolor photometry requires extremely high precision to discern between low-degree modes, yet has been used effectively to eliminate high-degree modes. Combining radial velocity (RV) and multicolor measurements has also been shown as an effective means of constraining mode identifications. We present preliminary results for Feige 48 and EC 01541-1409 using both time-resolved spectroscopy and multicolor photometry and an initial examination of their pulsation modes using the atmospheric codes BRUCE and KYLIE.

  3. Hypercalibration: A Pan-STARRS1-based Recalibration of the Sloan Digital Sky Survey Photometry

    NASA Astrophysics Data System (ADS)

    Finkbeiner, Douglas P.; Schlafly, Edward F.; Schlegel, David J.; Padmanabhan, Nikhil; Jurić, Mario; Burgett, William S.; Chambers, Kenneth C.; Denneau, Larry; Draper, Peter W.; Flewelling, Heather; Hodapp, Klaus W.; Kaiser, Nick; Magnier, E. A.; Metcalfe, N.; Morgan, Jeffrey S.; Price, Paul A.; Stubbs, Christopher W.; Tonry, John L.

    2016-05-01

    We present a recalibration of the Sloan Digital Sky Survey (SDSS) photometry with new flat fields and zero points derived from Pan-STARRS1. Using point-spread function (PSF) photometry of 60 million stars with 16 < r < 20, we derive a model of amplifier gain and flat-field corrections with per-run rms residuals of 3 millimagnitudes (mmag) in griz bands and 15 mmag in u band. The new photometric zero points are adjusted to leave the median in the Galactic north unchanged for compatibility with previous SDSS work. We also identify transient non-photometric periods in SDSS (“contrails”) based on photometric deviations co-temporal in SDSS bands. The recalibrated stellar PSF photometry of SDSS and PS1 has an rms difference of {9, 7, 7, 8} mmag in griz, respectively, when averaged over 15‧ regions.

  4. VizieR Online Data Catalog: uvby photometry of 4 CP stars (Adelman, 1997)

    NASA Astrophysics Data System (ADS)

    Adelman, S. J.

    1996-11-01

    Differential Stroemgren uvby photometric observations from the Four College Automated Photoelectric Telescope are presented for four magnetic chemically peculiar stars. Comparison with uvby photometry of Pedersen & Thomsen for HD 37776 yields an improved period of 1.538675 days. New periods of 15.0305 days and 18.065 days are found for the sharp-lined stars HR 2258 and HR 6958, respectively, rather than one of their aliases. For HR 6958 each color shows a slightly different time of maximum. Comparison of the four color photometry of 108 Aqr taken during the fall of 1995 which well covers the period shows the presence of a secondary minimum near primary maximum in u, v, and b. Comparison with published photometry indicates indicates that subtle changes in the shapes of the light curves have occurred suggesting that this star might be precessing. (5 data files).

  5. ASTERIA: A CubeSat for Exoplanet Transit and Stellar Photometry

    NASA Astrophysics Data System (ADS)

    Knapp, Mary; Seager, Sara

    2015-12-01

    We present ASTERIA, a 6U CubeSat demonstrator for exoplanet transit photometry. ASTERIA, currently in development at JPL and due to be launched in mid to late 2016, is a testbed for a two-stage pointing system capable of <10 arcsecond pointing as well as active thermal control. These two features will allow ASTERIA to achieve very high photometric precision (<100 ppm) in a very small and cost effective package. ASTERIA will be used to search for transits of known RV planets as well as perform long duration, high cadence stellar photometry. The stellar photometry data will be used to study flares and stellar activity on a variety of stellar types. This presentation will focus on ASTERIA's science mission.

  6. VizieR Online Data Catalog: Ks photometry of LMC RR Lyrae (Borissova+, 2009)

    NASA Astrophysics Data System (ADS)

    Borissova, J.; Rejkuba, M.; Minniti, D.; Catelan, M.; Ivanov, V. D.

    2009-06-01

    This paper presents new (single-epoch) J-band and (multi-epoch) Ks-band photometry of RR Lyr stars in 7 different LMC fields, observed with the near-IR camera SOFI at ESO's New Technology Telescope. Additional Ks-band data for another two LMC fields were taken with the ISPI infrared array at CTIO's Blanco 4m telescope. The near-IR photometry was cross-correlated with the MACHO and OGLE databases, resulting in a catalog of 62 RR Lyr stars with BV RIJKs photometry. A subsample of 50 stars also has spectroscopically mea sured metallicities. In the deep JK color-magnitude diagrams of 7 fields, red giant branch, red clump and RR Lyr stars are detected. (2 data files).

  7. Optical BVRI photometry of common proper motion F/G/K+M wide separation binaries

    SciTech Connect

    Li, Ting; Marshall, Jennifer L.; Williams, Patrick; Chavez, Joy; Lépine, Sébastien

    2014-10-01

    We present optical (BVRI) photometric measurements of a sample of 76 common proper motion wide separation main-sequence binary pairs. The pairs are composed of a F-, G-, or K-type primary star and an M-type secondary. The sample is selected from the revised NLTT catalog and the LSPM catalog. The photometry is generally precise to 0.03 mag in all bands. We separate our sample into two groups, dwarf candidates and subdwarf candidates, using the reduced proper motion diagram constructed with our improved photometry. The M subdwarf candidates in general have larger V – R colors than the M dwarf candidates at a given V – I color. This is consistent with an average metallicity difference between the two groups, as predicted by the PHOENIX/BT-Settl models. The improved photometry will be used as input into a technique to determine the metallicities of the M-type stars.

  8. Photoelectric photometry of Comet P/Halley from Mauna Kea Observatory

    NASA Technical Reports Server (NTRS)

    Piscitelli, J. R.; Tholen, D. J.; Hammel, H. B.; Lark, N.

    1986-01-01

    A program of photoelectric photometry of comet Halley yielded 60 nights of usable photometry. The uncertainty in the photometry in all filters except OH is better than 2%. Throughout the apparition, the comet is brightest in the filters that isolated the neutral gas emission features of OH, CN, C2, and C3. The fluxes in the filters that isolated the ionic emission features of CO(+) and H2O(+) are comparable to the continuum when centered upon the optocenter, thereby making the ionic emission weak to undetectable above the continuum. The continuum colors do not appear to be a function of phase angle; therefore, the colors are probably indicative of dust grain composition and are not dominated by scattering geometry effects.

  9. Stellar photometry with the Hubble Space Telescope Wide-field/Planetary camera - A progress report

    NASA Technical Reports Server (NTRS)

    Holtzman, Jon A.; Hunter, Deidre; Groth, Edward J.; Light, Robert M.; Faber, S. M.

    1991-01-01

    The prospects for the use of the Wide-Field/Planetary Camera (WFPC) for stellar photometry are described. The large halos of the point-spread function (PSF) resulting from spherical aberration and from spatial, temporal, and color variations of the PSF are the main limitations to accurate photometry. Degradations caused by crowding are exacerbated by the halos of the PSF. An attempt is made to quantify these effects and determine the current accuracy of stellar photometry with the WFPC. In realistic cases, the brighter stars in crowded fields have 0.09 mag errors; fainter stars have larger errors depending on the degree of crowding. It is shown that measuring Cepheids in Virgo Cluster galaxies is not currently possible without inordinate increases in exposure times.

  10. Star Clusters in M33: Updated UBVRI Photometry, Ages, Metallicities, and Masses

    NASA Astrophysics Data System (ADS)

    Fan, Zhou; de Grijs, Richard

    2014-04-01

    The photometric characterization of M33 star clusters is far from complete. In this paper, we present homogeneous UBVRI photometry of 708 star clusters and cluster candidates in M33 based on archival images from the Local Group Galaxies Survey, which covers 0.8 deg2 along the galaxy's major axis. Our photometry includes 387, 563, 616, 580, and 478 objects in the UBVRI bands, respectively, of which 276, 405, 430, 457, and 363 do not have previously published UBVRI photometry. Our photometry is consistent with previous measurements (where available) in all filters. We adopted Sloan Digital Sky Survey ugriz photometry for complementary purposes, as well as Two Micron All Sky Survey near-infrared JHK photometry where available. We fitted the spectral-energy distributions of 671 star clusters and candidates to derive their ages, metallicities, and masses based on the updated PARSEC simple stellar populations synthesis models. The results of our χ2 minimization routines show that only 205 of the 671 clusters (31%) are older than 2 Gyr, which represents a much smaller fraction of the cluster population than that in M31 (56%), suggesting that M33 is dominated by young star clusters (<1 Gyr). We investigate the mass distributions of the star clusters—both open and globular clusters—in M33, M31, the Milky Way, and the Large Magellanic Cloud. Their mean values are log (M cl/M ⊙) = 4.25, 5.43, 2.72, and 4.18, respectively. The fraction of open to globular clusters is highest in the Milky Way and lowest in M31. Our comparisons of the cluster ages, masses, and metallicities show that our results are basically in agreement with previous studies (where objects in common are available); differences can be traced back to differences in the models adopted, the fitting methods used, and stochastic sampling effects.

  11. Galaxy And Mass Assembly (GAMA): Accurate Panchromatic Photometry from Optical Priors using LAMBDAR

    NASA Astrophysics Data System (ADS)

    Wright, A. H.; Robotham, A. S. G.; Bourne, N.; Driver, S. P.; Dunne, L.; Maddox, S. J.; Alpaslan, M.; Andrews, S. K.; Bauer, A. E.; Bland-Hawthorn, J.; Brough, S.; Brown, M. J. I.; Cluver, M.; Davies, L. J. M.; Holwerda, B. W.; Hopkins, A. M.; Jarrett, T. H.; Kafle, P. R.; Lange, R.; Liske, J.; Loveday, J.; Moffett, A. J.; Norberg, P.; Popescu, C. C.; Smith, M.; Taylor, E. N.; Tuffs, R. J.; Wang, L.; Wilkins, S. M.

    2016-04-01

    We present the Lambda Adaptive Multi-band Deblending Algorithm in R (LAMBDAR), a novel code for calculating matched aperture photometry across images that are neither pixel- nor PSF-matched, using prior aperture definitions derived from high resolution optical imaging. The development of this program is motivated by the desire for consistent photometry and uncertainties across large ranges of photometric imaging, for use in calculating spectral energy distributions. We describe the program, specifically key features required for robust determination of panchromatic photometry: propagation of apertures to images with arbitrary resolution, local background estimation, aperture normalisation, uncertainty determination and propagation, and object deblending. Using simulated images, we demonstrate that the program is able to recover accurate photometric measurements in both high-resolution, low-confusion, and low-resolution, high-confusion, regimes. We apply the program to the 21-band photometric dataset from the Galaxy And Mass Assembly (GAMA) Panchromatic Data Release (PDR; Driver et al. 2016), which contains imaging spanning the far-UV to the far-IR. We compare photometry derived from LAMBDAR with that presented in Driver et al. (2016), finding broad agreement between the datasets. Nonetheless, we demonstrate that the photometry from LAMBDAR is superior to that from the GAMA PDR, as determined by a reduction in the outlier rate and intrinsic scatter of colours in the LAMBDAR dataset. We similarly find a decrease in the outlier rate of stellar masses and star formation rates using LAMBDAR photometry. Finally, we note an exceptional increase in the number of UV and mid-IR sources able to be constrained, which is accompanied by a significant increase in the mid-IR colour-colour parameter-space able to be explored.

  12. Photometric Analysis for the Kepler Mission: Optimal Aperture Photometry and Difference Image Analysis

    NASA Astrophysics Data System (ADS)

    Jenkins, Jon M.; Gilliland, R. L.; Chandrasekaran, H.; Bryson, S. T.; Caldwell, D. A.; Borucki, W. J.

    2006-12-01

    The science processing pipeline for the Kepler Science Operations Center will use two different approaches for developing stellar flux time series from the pixels downlinked from the spacecraft: Difference Image Analysis (DIA) Photometry and Optimal Aperture Photometry (OAP). We have prototyped both approaches and applied them to artificial data sets containing a wealth of realistic astrophysical phenomena including transiting planets, stellar variability, background eclipsing binaries and differential velocity aberration (DVA). These data sets were furnished using the Kepler End to End Model (see Bryson et al., this session). The primary purpose of the study was to investigate the effect of DVA on the ability of the Kepler processing pipeline to: 1) obtain high precision, high fidelity stellar flux time series, 2) to detect signatures of transiting planets in the data set, and 3) to reject false positives represented by background eclipsing binary systems. OAP photometry is an extension of the optimal pixel weighting photometry introduced by Jenkins et al. 2000 (ProcSPIE 4013) and is motivated by the slow drift of the stars on the CCDs by up to 0.6 pixels over three months compared to the tight pointing requirements for the attitude control system (0.01 = 1 σ at 15 minutes). The photometry from OAP consists of taking a weighted sum of the pixels in each target's aperture, where the weights are functions of the change in position of the target and hence, can mitigate the large apparent changes in stellar flux for simple aperture photometry. The results of the study indicate that DIA and OAP produce comparable photometric time series, and furthermore, that DVA does not interfere with the ability of Kepler to detect such planets or to reject false positives from background eclipsing binaries. The Kepler Mission is funded by NASA's Discovery Program.

  13. FAINT NEAR-ULTRAVIOLET/FAR-ULTRAVIOLET STANDARDS FROM SWIFT/UVOT, GALEX, AND SDSS PHOTOMETRY

    SciTech Connect

    Siegel, Michael H.; Hoversten, Erik A.; Roming, Peter W. A.; Brown, Peter E-mail: hoversten@astro.psu.ed E-mail: brown@astro.psu.ed

    2010-12-10

    At present, the precision of deep ultraviolet photometry is somewhat limited by the dearth of faint ultraviolet standard stars. In an effort to improve this situation, we present a uniform catalog of 11 new faint (u {approx} 17) ultraviolet standard stars. High-precision photometry of these stars has been taken from the Sloan Digital Sky Survey and Galaxy Evolution Explorer archives and combined with new data from the Swift Ultraviolet Optical Telescope to provide precise photometric measures extending from the near-infrared to the far-ultraviolet. These stars were chosen because they are known to be hot (20, 000 < T{sub eff} < 50, 000 K) DA white dwarfs with published Sloan spectra that should be photometrically stable. This careful selection allows us to compare the combined photometry and Sloan spectroscopy to models of pure hydrogen atmospheres to both constrain the underlying properties of the white dwarfs and test the ability of white dwarf models to predict the photometric measures. We find that the photometry provides good constraints on white dwarf temperatures, which demonstrates the ability of Swift/UVOT to investigate the properties of hot luminous stars. We further find that the models reproduce the photometric measures in all 11 passbands to within their systematic uncertainties. Within the limits of our photometry, we find the standard stars to be photometrically stable. This success indicates that the models can be used to calibrate additional filters to our standard system, permitting easier comparison of photometry from heterogeneous sources. The largest source of uncertainty in the model fitting is the uncertainty in the foreground reddening curve, a problem that is especially acute in the UV.

  14. Precision of a Low-Cost InGaAs Detector for Near Infrared Photometry

    NASA Astrophysics Data System (ADS)

    Sullivan, Peter W.; Croll, Bryce; Simcoe, Robert A.

    2013-09-01

    We have designed, constructed, and tested an InGaAs near-infrared camera to explore whether low-cost detectors can make small (<= 1 m) telescopes capable of precise (< 1 mmag) infrared photometry of relatively bright targets. The camera is constructed around the 640 × 512 pixel APS640C sensor built by FLIR Electro-Optical Components. We designed custom analog-to-digital electronics for maximum stability and minimum noise. The InGaAs dark current halves with every 7°C of cooling, and we reduce it to 840 e- s-1 pixel-1 (with a pixel-to-pixel variation of ± 200 e- s-1 pixel-1) by cooling the array to -20°C. Beyond this point, glow from the readout dominates. The single-sample read noise of 149 e- is reduced to 54 e- through up-the-ramp sampling. Laboratory testing with a star field generated by a lenslet array shows that two-star differential photometry is possible to a precision of 631 ± 205 ppm (0.68 mmag) hr-1/2 at a flux of 2.4 × 104 e- s-1. Employing three comparison stars and decorrelating reference signals further improves the precision to 483 ± 161 ppm (0.52 mmag) hr-1/2. Photometric observations of HD80606 and HD80607 (J = 7.7 and 7.8) in the Y band shows that differential photometry to a precision of 415 ppm (0.45 mmag) hr-1/2 is achieved with an effective telescope aperture of 0.25 m. Next-generation InGaAs detectors should indeed enable Poisson-limited photometry of brighter dwarfs with particular advantage for late-M and L types. In addition, one might acquire near-infrared photometry simultaneously with optical photometry or radial velocity measurements to maximize the return of exoplanet searches with small telescopes.

  15. STAR CLUSTERS IN M33: UPDATED UBVRI PHOTOMETRY, AGES, METALLICITIES, AND MASSES

    SciTech Connect

    Fan, Zhou; De Grijs, Richard E-mail: grijs@pku.edu.cn

    2014-04-01

    The photometric characterization of M33 star clusters is far from complete. In this paper, we present homogeneous UBVRI photometry of 708 star clusters and cluster candidates in M33 based on archival images from the Local Group Galaxies Survey, which covers 0.8 deg{sup 2} along the galaxy's major axis. Our photometry includes 387, 563, 616, 580, and 478 objects in the UBVRI bands, respectively, of which 276, 405, 430, 457, and 363 do not have previously published UBVRI photometry. Our photometry is consistent with previous measurements (where available) in all filters. We adopted Sloan Digital Sky Survey ugriz photometry for complementary purposes, as well as Two Micron All Sky Survey near-infrared JHK photometry where available. We fitted the spectral-energy distributions of 671 star clusters and candidates to derive their ages, metallicities, and masses based on the updated PARSEC simple stellar populations synthesis models. The results of our χ{sup 2} minimization routines show that only 205 of the 671 clusters (31%) are older than 2 Gyr, which represents a much smaller fraction of the cluster population than that in M31 (56%), suggesting that M33 is dominated by young star clusters (<1 Gyr). We investigate the mass distributions of the star clusters—both open and globular clusters—in M33, M31, the Milky Way, and the Large Magellanic Cloud. Their mean values are log (M {sub cl}/M {sub ☉}) = 4.25, 5.43, 2.72, and 4.18, respectively. The fraction of open to globular clusters is highest in the Milky Way and lowest in M31. Our comparisons of the cluster ages, masses, and metallicities show that our results are basically in agreement with previous studies (where objects in common are available); differences can be traced back to differences in the models adopted, the fitting methods used, and stochastic sampling effects.

  16. Temperature mapping of sunspots and pores from speckle reconstructed three colour photometry

    NASA Astrophysics Data System (ADS)

    Suetterlin, P.; Wiehr, E.

    1998-08-01

    The two-dimensional temperature distribution in a highly structured sunspot and in two small umbrae is determined from a three-colour photometry in narrow spectral continua. Disturbing influences from the earth's atmosphere are removed by speckle masking techniques, yielding a spatial resolution limited by the telescope's aperture. The corresponding colour temperatures are consistent over a range of more than 2000 K, although the numerical correction introduced by the reconstruction differs largely for the three colours. Part of the scatter in the temperature relation disappears when convoluting the final images with artificial PSFs that compensate for the different, colour dependent spatial resolution. The remaining spread in the scatter plots does not reflect noise, but is related to local variations of the temperature difference between the continuum emitting layers. This is most obvious for a small umbra which yields `branches' in the scatter plots the `bluer' of which corresponding to the limb-side umbral border. Here, the `hot rim' of a Wilson depressed umbra becomes visible. The temperature map of the large spot shows that the bright umbral dots do not reach the temperature of the non-spot surroundings. Instead, they exceed the 2000 K cooler umbral temperature minimum by 900-1300 K. The filamentary structure of the surrounding penumbra has spatial temperature fluctuations of typically 700 K, a value which fits earlier observed contrasts. However, the mean temperatures of 5650 K in the dark and 6250 K in the bright penumbral fine structures exceed former findings. Exceptionally bright penumbral grains are 250 K hotter than the mean solar surface and thus exceed even brightest granules.

  17. TIME-SERIES BVI PHOTOMETRY FOR THE GLOBULAR CLUSTER NGC 6981 {sup ,} {sup ,}

    SciTech Connect

    Amigo, P.; Catelan, M.; Zoccali, M.; Stetson, P. B.; Smith, H. A. E-mail: mzoccali@astro.puc.cl E-mail: Peter.Stetson@nrc-cnrc.gc.ca

    2013-11-01

    We present new BVI photometry of the globular cluster NGC 6981, based mostly on ground-based CCD archival images. We present a new color-magnitude diagram (CMD) that reaches almost four magnitudes below the turn-off level. We performed new derivations of metallicity and morphological parameters of the evolved sequences, in good agreement with the results of previous authors, and obtain a value of [Fe/H] ≅ –1.50 in the new UVES scale. We also identify the cluster's blue straggler population. Comparing the radial distribution of these stars with the red giant branch population, we find that the blue stragglers are more centrally concentrated, as found in previous studies of blue stragglers in globular clusters. Taking advantage of the large field of view covered by our study, we analyzed the surface density profile of the cluster, and find extratidal main sequence stars out to r ≈ 14.'1, or about twice the tidal radius. We speculate that the presence of these stars may be due to tidal disruption in the course of NGC 6981's orbit, in which case tidal tails associated with the cluster may exist. We also take a fresh look at the variable stars in the cluster, recovering all previously known variables, including three SX Phoenicis stars. We also add three previously unknown RR Lyrae (one c-type and two ab-type) to the total census. Finally, comparing our CMD with unpublished data for M3 (NGC 5272), a cluster with a similar metallicity and horizontal branch morphology, we found that both objects are essentially coeval.

  18. Diagnostics of stellar modelling from spectroscopy and photometry of globular clusters

    NASA Astrophysics Data System (ADS)

    Angelou, George C.; D'Orazi, Valentina; Constantino, Thomas N.; Church, Ross P.; Stancliffe, Richard J.; Lattanzio, John C.

    2015-07-01

    We conduct a series of comparisons between spectroscopic and photometric observations of globular clusters and stellar models to examine their predictive power. Data from medium-to-high resolution spectroscopic surveys of lithium allow us to investigate first dredge-up and extra mixing in two clusters well separated in metallicity. Abundances at first dredge-up are satisfactorily reproduced but there is preliminary evidence to suggest that the models overestimate the luminosity at which the surface composition first changes in the lowest metallicity system. Our models also begin extra mixing at luminosities that are too high, demonstrating a significant discrepancy with observations at low metallicity. We model the abundance changes during extra mixing as a thermohaline process and determine that the usual diffusive form of this mechanism cannot simultaneously reproduce both the carbon and lithium observations. Hubble Space Telescope photometry provides turn-off and bump magnitudes in a large number of globular clusters and offers the opportunity to better test stellar modelling as function of metallicity. We directly compare the predicted main-sequence turn-off and bump magnitudes as well as the distance-independent parameter Δ M_V ^{MSTO}_{bump}. We require 15 Gyr isochrones to match the main-sequence turn-off magnitude in some clusters and cannot match the bump in low-metallicity systems. Changes to the distance modulus, metallicity scale and bolometric corrections may impact on the direct comparisons but Δ M_V ^{MSTO}_{bump}, which is also underestimated from the models, can only be improved through changes to the input physics. Overshooting at the base of the convective envelope with an efficiency that is metallicity dependent is required to reproduce the empirically determined value of Δ M_V ^{MSTO}_{bump}.

  19. Extreme ultraviolet spectroscopy and photometry of VV Puppis during a high accretion state

    NASA Technical Reports Server (NTRS)

    Vennes, Stephane; Szkody, Paula; Sion, Edward M.; Long, Knox S.

    1995-01-01

    We determine the physical properties of the accretion region of the AM Her-type binary VV Puppis using extreme ultraviolet (EUV) medium-resolution spectroscopy and photometry obtained with the Extreme Ultraviolet Explorer (EUVE) observatory. The EUV continuum from VV Pup was detected in the wavelength range from 75 to 135 A and was simultaneously recorded with the Deep Survey/Spectrometer (DS/S) imaging telescope, allowing for the extraction of an accurate light curve. VV Pup appeared to have entered a high-accretion state just prior to the pointed EUVE observations. We use the EUV light curve to infer the diameter of the accretion region (d = 220 km) assuming a hemispherical geometry and a radius of 9000 km for the white dwarf. We perform a model atmosphere analysis and, based on the light curve properties and assuming a distance of 145 pc, we derive an effective temperature of the accretion region in the range 270,000 is less than T(sub eff) is less than 360,000 K and a neutral hydrogen column density in the local interstellar medium of n(sub H) = 1.9 - 3.7 x 10(exp 19)/sq cm. The total EUV/soft X-ray energy radiated by the accretion region is approximately 3.5 x 10(exp 32) ergs/s. Our results provide a first verification of past suggestions that deep heating of the white dwarf surface produces the soft X-ray flux from the polars. We present a possible detection of O VI absortion features, and we suggest that extensive EUVE observations targeting high-accretion events may result in oxygen and heavier element abundance determination in the accretion region.

  20. A New Look at Factors Affecting Microbial Silicification: Effects of Microbe to Solution Ratio, Al and Fe on Silica Accumulation on B. subtilis Surfaces

    NASA Astrophysics Data System (ADS)

    Tenesch, A. C.; Hinman, N. W.; Blank, C. E.

    2006-12-01

    In this investigation, we aim to constrain the geochemical conditions that favor siliceous microfossil formation. This work will provide a framework for assessing the biogenic origin of putative microfossils in siliceous hydrothermal deposits on early Earth, and potentially, on Mars. Previous work on silicification of microbial cells has been done under unnatural conditions or when cells were physiological stressed. Here, we attempt to reduce the amount reduce the amount of physiological stress on the organisms and to better emulate the natural environment. Silicification experiments involving the gram-positive bacterium, Bacillus subtilis, have been conducted under different experimental conditions to provide insight into the processes that affect silicification of microorganisms. Experiments were conducted with silica stock solution at an initial pH of 8, and with and without added Al and Fe, in two different experimental designs. The first experimental design represented a silica-limited environment in which the ratio of exponentially growing culture (O.D.600 = 0.2) to silica-rich stock solution was very high (1:1 v/v). Silica concentrations declined likely due to nucleation and precipitation mediated by microbial surfaces, and the pH dropped from 8.0 to 6.5. The presence of Fe and Al resulted in lower dissolved silica concentrations, suggesting additional effects of these ions on nucleation and precipitation. The second experimental design used a lower ratio of exponentially growing culture (O.D.600 = .2) to silica-rich stock solution (0.004:1 v/v) resulting in a stable concentration of silica, which was also accompanied by a slight decline in pH. This latter design is more similar to the cell:silica ratios found in natural environments. B. subtilis cells were examined using scanning electron microscopy (SEM) accompanied by energy dispersive spectrometry (EDS). Cells exhibited silica crystallites under SEM and yet continued to undergo cell division in an environment of limited resources. Silicification in the low-ratio experiments appeared to be more efficient as cells were more encrusted with Si than cells in the high-ratio experiments. Further, sporulation was more efficient in the low-ratio experiments.

  1. HUBBLE SPACE TELESCOPE Survey of Clusters in Nearby Galaxies. I. Detection and Photometry

    NASA Astrophysics Data System (ADS)

    Dolphin, Andrew E.; Kennicutt, Robert C., Jr.

    2002-01-01

    We have developed photometric techniques that can be applied to images with highly variable backgrounds, as well as to slightly extended objects (object size comparable to or smaller than point-spread function [PSF] size). We have shown that ordinary stellar PSF-fitting photometry can be applied to slightly extended objects provided that one applies a systematic correction to the photometry that is a function primarily of the observed sharpness. Applying these techniques to the Cepheid target NGC 3627, we find that we are successfully able to photometer the stars and clusters, as well as discriminate the cluster population with a negligible number of false detections.

  2. Spectroscopy and photometry of the nova M31N 2014-01a at maximum

    NASA Astrophysics Data System (ADS)

    Fabrika, S.; Barsukova, E. A.; Valeev, A. F.; Sholukhova, O.; Hornoch, K.; Shafter, A. W.; Henze, M.

    2014-01-01

    We report optical spectroscopy and photometry of the recent M31 nova candidate M31N 2014-01a (= PNV J00431362+4114469) detected by the Lick Observatory Supernova Search on 2014 Jan. 02.13 UT (http://www.cbat.eps.harvard.edu/unconf/followups/J00431362+4114469.html ) and also observed on 2014 Jan. 05.42 UT as a 16.4 mag object by T. Yusa and K. Kato (Japan). Using the Russian BTA telescope equipped with the SCORPIO spectrograph we have obtained spectra and photometry of the nova M31N 2014-01a on 2014 Jan.

  3. U-B-V photometry of the spectroscopic-visual triple HD 165590

    NASA Astrophysics Data System (ADS)

    Bruton, J. R.; Hall, D. S.; Boyd, L. J.; Genet, R. M.; Lines, R. D.

    1989-05-01

    Results of photoelectric UBV photometry from Lines (1983) and V photometry from Scarfe (1977), together with observation results from the Automatic Photoelectric Telescope (APT) on the triple HD 165590 visual binary, all obtained between 1977 and 1986, are examined, using a FORTRAN program to analyze the noneclipse light variations. A new linear ephemeris is obtained, which shows that the orbital period of Aa = Ab is constant, within the uncertainties of the available times of mid-primary eclipse and times of conjunction derived from the analysis of the ellipticity effect.

  4. Photometry and imaging of the peculiar planetary nebula IRAS 21282 + 5050

    NASA Technical Reports Server (NTRS)

    Kwok, Sun; Hrivnak, Bruce J.; Langill, Philip P.

    1993-01-01

    We report visible, near-infrared, and mid-infrared photometry of the IRAS planetary nebula 21282+ 5050. Narrow-band photometry at 10 microns confirms the presence of the 11.3-micron PAH feature. IRAS 21282+5050 belongs to a small group of planetary nebulae with WC11 nuclei and PAH emission. The spectral energy distribution shows that majority of the flux is emitted in the infrared, and the object has one of the highest infrared excesses among all planetary nebulae. Optical imaging (after subtraction of the central star) reveals a nebula of size of about 7 x 5 arcsec which is elongated along the N-S direction.

  5. VizieR Online Data Catalog: gr photometry of Sextans A and Sextans B (Bellazzini+, 2014)

    NASA Astrophysics Data System (ADS)

    Bellazzini, M.; Beccari, G.; Fraternali, F.; Oosterloo, T. A.; Sollima, A.; Testa, V.; Galleti, S.; Perina, S.; Faccini, M.; Cusano, F.

    2014-04-01

    The tables present deep LBT/LBC g and r photometry of the stars having image quality parameters (provided by DAOPHOTII) CHI<=2 and SHARP within magnitude-dependent contours traced to include the bulk of stellar objects. The observations were achieved on the night og 2012-02-21 with the Large Binocular Camera at the Large Binocular Telescope in binocular mode; g images were acquired with the blue arm and r images with the red arm of the telescope/camera. The astrometry and the photometry were calibrated with stars in common with SDSS-DR9 (V/139). (2 data files).

  6. Documentation for the machine-readable version of a catalogue of homogeneous photometry of bright stars on the DDO system

    NASA Technical Reports Server (NTRS)

    Warren, W. H., Jr.

    1982-01-01

    The magnetic tape version of the Catalog of Homogeneous Photometry of Bright Stars on the DDO System is described. The catalog represents a compilation of DDO photometry of 2196 bright G and K stars prepared from observations made at Kitt Peak National and Cerro Tololo Inter-American observatories. Stars representative of good velocities, spectral types, and freedom from companion contamination are presented.

  7. VizieR Online Data Catalog: Photometry in cluster 2158+0351 at z=0.45 (Molinari+ 1990)

    NASA Astrophysics Data System (ADS)

    Molinari, E.; Buzzoni, A.; Chincarini, G.

    1993-03-01

    Results of detailed 3-colour photometry of the distant cluster 2158+0351 (z=0.445) are presented. The photometry was produced using the INVENTORY package. The Gunn g, r, i magnitudes were measureed, down to r = 23.5, with a typical error of 0.1mag. (1 data file).

  8. Results of near-Earth-asteroid photometry in the frame of the ASPIN programme

    NASA Astrophysics Data System (ADS)

    Krugly, Y.; Molotov, I.; Inasaridze, R.; Kvaratskhelia, O.; Aivazyan, V.; Rumyantsev, V.; Belskaya, I.; Golubaev, A.; Sergeev, A.; Shevchenko, V.; Slyusarev, I.; Burkhonov, O.; Ehgamberdiev, S.; Elenin, L.; Voropaev, V.; Koupianov, V.; Gaftonyuk, N.; Baransky, A.; Irsmambetova, T.; Litvinenko, E.; Aliev, A.; Namkhai, T.

    2014-07-01

    Regular photometric observations aimed for obtaining physical properties of near-Earth asteroids (NEA) are carried out within the Asteroid Search and Photometry Initiative (ASPIN) of the International Scientific Optical Network (ISON). At present, ISON project joins 35 observation facilities in 15 countries with 80 telescopes of different class. Photometric observations of NEAs are carried out at the telescopes with apertures from 20 cm up to 2.6 m equipped with CCD cameras. The obtained lightcurves in the Johnson-Cousins photometric system or in exceptional cases in the integral light (unfiltered photometry) have typical photometric accuracy of 0.01-0.03 mag. The main targets of these observations are near-Earth asteroids as hazardous objects pose a threat for the Earth civilization. The main purpose of the observations is to study characteristics of asteroids such as rotation period, size, and shape of the body, and surface composition. The observations are aimed toward searching binary asteroids, supporting the asteroid radar observations and investigation of the YORP effect. In 2013, we have observed 40 near-Earth asteroids in more than 200 nights. The rotation periods have been determined for 14 NEAs for the first time and, for 6 NEAs, rotation periods were defined more precisely. New rotation periods have been obtained for objects from Aten group: (137805) 1999 YK_5, (329437) 2002 OA_{22}, (367943) Duende (2012 DA_{14}); Apollo: (17188) 1999 WC_2, (137126) 1999 CF_9, (163249) 2002 GT, (251346) 2007 SJ, 2013 TV_{135}; Amor: (9950) ESA, (24445) 2000 PM_8, (137199) 1999 KX_4, (285263) 1998 QE_2, (361071) 2006 AO_4, 2010 XZ_{67}, and refined for (1943) Anteros, (3361) Orpheus, (3752) Camillo, (7888) 1993 UC, (53435) 1999 VM_{40}, (68216) 2001 CV_{26}. NEAs (7888) 1993 UC and (68216) 2001 CV_{26} were found to show signs of a binary nature. To detect possible binary asteroids, we observe the object during several consecutive nights and at several observatories located at different longitudes. In particular, to cover a long time interval and not to miss the eclipse/occultation minima, the binary NEA (285263) 1998 QE_2 has been observed in close dates in Ukraine, Georgia, Tajikistan, Mongolia, the Far East of Russia, and Mexico. To test an influence of the YORP effect on the spin rates, the lightcurves of NEAs (2100) Ra-Shalom, 88710 2001 SL_9, and (138852) 2000 WN_{10} have been obtained. The observations of small NEAs (with diameters smaller 200 m) have revealed very fast rotating NEAs with rotation periods smaller than 2.2 hours for (363305) 2002 NV_{16}, 2000 KA, and 2013 QR_1. Many of our targets were also the targets of the radar observations in the Arecibo and the Goldstone. The obtained results will be presented and the perspectives of the ASPIN programme will be discussed.

  9. Adhesion of Streptococcus mitis and Actinomyces oris in co-culture to machined and anodized titanium surfaces as affected by atmosphere and pH

    PubMed Central

    2013-01-01

    Background With the rising demand for osseointegrated titanium implants for replacing missing teeth, often in patients with a history of periodontitis, implant-related infections have become an issue of growing concern. Novel methods for treating and preventing implant-associated infections are urgently needed. The aim of this study was to investigate if different pH, atmosphere and surface properties could restrict bacterial adhesion to titanium surfaces used in dental implants. Methods Titanium discs with machined or anodized (TiUnite™) surface were incubated with a co-culture of Streptococcus mitis and Actinomyces oris (early colonizers of oral surfaces) at pH 5.0, 7.0 and 9.0 at aerobic or anaerobic atmosphere. The adhesion was analysed by counting colony forming (CFU) units on agar and by confocal laser scanning microscopy (CLSM). Results The CFU analysis showed that a pH of 5.0 was found to significantly decrease the adhesion of S. mitis, and an aerobic atmosphere, the adhesion of A. oris. S. mitis was found in significantly less amounts on the anodized surface than the machined surface, while A. oris was found in equal amounts on both surfaces. The CLSM analysis confirmed the results from the CFU count and provided additional information on how the two oral commensal species adhered to the surfaces: mainly in dispersed clusters oriented with the groves of the machined surface and the pores of the anodized surface. Conclusions Bacterial adhesion by S. mitis and A. oris can be restricted by acidic pH and aerobic atmosphere. The anodized surface reduced the adhesion of S. mitis compared to the machined surface; while A. oris adhered equally well to the pores of the anodized surface and to the grooves of the machined surface. It is difficult to transfer these results directly into a clinical situation. However, it is worth further investigating these findings from an in vitro perspective, as well as clinically, to gain more knowledge of the effects acid pH and aerobic atmosphere have on initial bacterial adhesion. PMID:23298213

  10. VizieR Online Data Catalog: Multiband surface photometry of 21 BCGs (Micheva+ 2013)

    NASA Astrophysics Data System (ADS)

    Micheva, G.; Ostlin, G.; Zackrisson, E.; Bergvall, N.; Marquart, T.; Masegosa, J.; Marquez, I.; Cumming, R. J.; Durret, F.

    2013-07-01

    The data consist of optical and NIR broadband imaging (UBVRIHKs), obtained during the period 2003-2007 with ALFOSC (at the Nordic Optical Telescope, NOT, La Palma), MOSCA (NOT), and EMMI (at the European Southern Observatory New Technology Telescope, ESO NTT, La Silla) in the optical, and with NOTCAM (NOT) and SOFI (ESO NTT) in the NIR. Very deep observations are of a volume-limited sample of 21 Blue Compact Galaxies (Emission line galaxies). The images are reduced (bias correction, flatfielding, normalized, aligned, skysubtracted). Calibration to the Vega photometric system in the optical based on Landolt standard stars; in the NIR on 2MASS field stars found in each frame. Total exposure time (seconds) in each filter and galaxy is included in each FITS header as TOTALTIM. Cosmic rays have not been removed. (4 data files).

  11. VizieR Online Data Catalog: Surface photometry of local dwarf galaxies (Sharina+, 2008)

    NASA Astrophysics Data System (ADS)

    Sharina, M. E.; Karachentsev, I. D.; Dolphin, A. E.; Karachentseva, V. E.; Tully, R. B.; Karataeva, G. M.; Makarov, D. I.; Makarova, L. N.; Sakai, S.; Shaya, E. J.; Nikolaev, E. Y.; Kuznetsov, A. N.

    2009-04-01

    Our sample (see Table 1) consists of 104 dwarf galaxies observed with the Wide Field and Planetary Camera 2 (WFPC2) using the WF3-fix aperture (proposals GO 8192 and 8601) and with the Advanced Camera for Surveys (ACS) (proposals 9771 and 10235). All HST observations were carried out with the filters F606W and F814W, the response characteristics of which can be transformed to the filters V and I in the Johnson-Cousins system. The exposure times were 600s in each filter for the WFPC2 sample. The ACS images were taken with the exposure times of 900 and 1200s in the F606W and F814W filters, respectively. (2 data files).

  12. VizieR Online Data Catalog: Surface photometry of BCD galaxies (Gil de Paz+, 2005)

    NASA Astrophysics Data System (ADS)

    Gil de Paz, A.; Madore, B. F.

    2005-07-01

    In Paper I (Gil de Paz+, 2003, J/ApJS/147/29) we presented an extensive description of the observations. Briefly, we observed 86 of the 114 Atlas galaxies at the Palomar 60 inch (1.524m) telescope using a 2048x2048 CCD in B, R, and the appropriately redshifted H? narrowband filter (??~20). The remaining 28 galaxies were observed at the Las Campanas Observatory 100 inch (2.54m) (du Pont) telescope using a similar 2048x2048 CCD (with narrowband H? of ??~65). (3 data files).

  13. UBV photometry of V934 Her in the X-ray outburst

    NASA Astrophysics Data System (ADS)

    Metlova, N. V.; Goranskij, V. P.

    2014-09-01

    After Swift detection of the X-ray outburst in the system of M2 III giant with a neutron star V934 Her (4U 1700+24, HD 154791) on 18 Sep 2014 (ATel #6482), we perform its optical photometry at the Sternberg Astronomical Institute Crimean Station using 60 cm telescope and Lyuty's photoelectric UBV photometer.

  14. CCD photometry and astrometry in the selected regions C and E in the Large Magellanic Cloud.

    NASA Astrophysics Data System (ADS)

    Will, J.-M.; Bomans, D. J.; Tucholke, H.-J.; de Boer, K. S.; Grebel, E. K.; Richtler, T.; Seggewiss, W.; Vallenari, A.

    1995-09-01

    In this paper we present CCD data of objects in the LMC selected regions C and E. These data include the young globular cluster NGC 1818, the association NGC 1948, and the intermediate age cluster NGC 1978. We discuss the calibration of the data and provide complete tables of the photometry and astrometry of all stars within our field of view.

  15. New shape models of asteroids reconstructed from sparse-in-time photometry

    NASA Astrophysics Data System (ADS)

    Durech, Josef; Hanus, Josef; Vanco, Radim; Oszkiewicz, Dagmara Anna

    2015-08-01

    Asteroid physical parameters - the shape, the sidereal rotation period, and the spin axis orientation - can be reconstructed from the disk-integrated photometry either dense (classical lightcurves) or sparse in time by the lightcurve inversion method. We will review our recent progress in asteroid shape reconstruction from sparse photometry. The problem of finding a unique solution of the inverse problem is time consuming because the sidereal rotation period has to be found by scanning a wide interval of possible periods. This can be efficiently solved by splitting the period parameter space into small parts that are sent to computers of volunteers and processed in parallel. We will show how this approach of distributed computing works with currently available sparse photometry processed in the framework of project Asteroids@home. In particular, we will show the results based on the Lowell Photometric Database. The method produce reliable asteroid models with very low rate of false solutions and the pipelines and codes can be directly used also to other sources of sparse photometry - Gaia data, for example. We will present the distribution of spin axis of hundreds of asteroids, discuss the dependence of the spin obliquity on the size of an asteroid,and show examples of spin-axis distribution in asteroid families that confirm the Yarkovsky/YORP evolution scenario.

  16. VizieR Online Data Catalog: Hipparcos photometry of CP stars (Adelman 1998)

    NASA Astrophysics Data System (ADS)

    Adelman, S. J.

    1998-06-01

    The Hipparcos photometry of the chemically peculiar main-sequence B, A and F stars are examined for variability. Some non-magnetic CP stars, Mercury-Manganese and metallic-line stars, which according to canonical wisdom should not be variable, may be variable and are identified for further study. Some potentially important magnetic CP stars are noted. (3 data files).

  17. VizieR Online Data Catalog: Carrier fit analysis of LQ Hya photometry (Olspert+, 2015)

    NASA Astrophysics Data System (ADS)

    Olspert, N.; Kapyla, M. J.; Pelt, J.; Cole, E. M.; Hackman, T.; Lehtinen, J.; Henry, G. W.

    2015-02-01

    The epochs as well as differential magnitudes of primary and secondary minima obtained from the model are presented. The analysis was done for the homogeneous data set D2 as denoted in the paper (photometry obtained with the T3 0.4m APT at the Fairborn Observatory). (1 data file).

  18. Spectroscopy and photometry of the nova candidate M33N 2013-12a

    NASA Astrophysics Data System (ADS)

    Fabrika, S.; Barsukova, E. A.; Valeev, A. F.; Sholukhova, O.; Hornoch, K.; Shafter, A. W.; Henze, M.

    2014-01-01

    We report optical spectroscopy and photometry of a recent M33 nova candidate (M33N 2013-12a = PNV J01331092+3037511) detected by the Lick Observatory Supernova Search ( http://www.cbat.eps.harvard.edu/unconf/followups/J01331092+3037511.html ).

  19. AN UPDATED CATALOG OF M33 CLUSTERS AND CANDIDATES: UBVRI PHOTOMETRY AND SOME STATISTICAL RESULTS

    SciTech Connect

    Ma Jun

    2012-08-15

    We present UBVRI photometry for 392 star clusters and candidates in the field of M33, which are selected from the most recent star cluster catalog. In this catalog, the authors listed star clusters' parameters such as cluster positions, magnitudes, colors in the UBVRIJHK{sub s} filters, and so on. However, a large fraction of objects in this catalog do not have previously published photometry. Photometry is performed using archival images from the Local Group Galaxies Survey, which covers 0.8 deg{sup 2} along the major axis of M33. Detailed comparisons show that, in general, our photometry is consistent with previous measurements. Positions (right ascension and declination) for some clusters are corrected here. Combined with previous literature, ours constitute a large sample of M33 star clusters. Based on this cluster sample, we present some statistical results: none of the youngest M33 clusters ({approx}10{sup 7} yr) have masses approaching 10{sup 5} M{sub Sun} ; roughly half the star clusters are consistent with the 10{sup 4}-10{sup 5} M{sub Sun} mass models; the continuous distribution of star clusters along the model line indicates that M33 star clusters have been formed continuously from the epoch of the first star cluster formation until recent times; and there are {approx}50 star clusters which are overlapped with the Galactic globular clusters on the color-color diagram, and these clusters are old globular cluster candidates in M33.

  20. Physical studies of asteroids. XXV - Photoelectric photometry of asteroids obtained at ESO and Hoher List Observatory

    NASA Astrophysics Data System (ADS)

    Lagerkvist, C.-I.; Magnusson, P.; Debehogne, H.; Hoffmann, M.; Erikson, A.; de Campos, A.; Cutispoto, G.

    1992-11-01

    Photoelectric photometry of 14 asteroids, carried out at ESO and the Hoher List Observatory during 1990 and 1991, are presented. Composite lightcurves were derived for the asteroids 140 Siwa, 238 Hypatia, 347 Pariana, 389 Industria and 1593 Fagnes. UBV colors are also given for ten of the asteroids.