These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

CCD surface photometry of galaxies  

NASA Technical Reports Server (NTRS)

We present here the results based on analysis of broad band optical images of radio loud and radio quiet galaxies selected from a set of x-ray galaxies. Data reduction techniques, and surface photometry using the IRAF data reduction package are described. The radial surface brightness profile of each galaxy is obtained. The disc, bulge, and nucleus of the galaxy are modeled based on the estimated brightness profile. The model of the galaxy is constructed, which is subtracted from the observed image to enhance the small scale features in the galaxy. Color maps of the galaxy are obtained and compared with those of normal galaxies. The optical properties of the galaxy are compared with its x-ray and radio properties.

Anupama, G. C.; Kembhavi, A. K.

1992-01-01

2

Hubble Deep Field surface photometry (Fasano+ 1998)  

Microsoft Academic Search

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 (Couch,

G. Fasano; M. Filippi; F. Bertola

1997-01-01

3

Surface photometry of WINGS galaxies with GASPHOT  

E-print Network

Aims. We present the B-, V- and K-band surface photometry catalogs obtained running the automatic software GASPHOT on galaxies from the WINGS cluster survey having isophotal area larger than 200 pixels. The catalogs can be downloaded at the Centre de Donnees Astronomiques de Strasbourg (CDS). Methods. 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 generally achieved by the softwares for automatic surface photometry of galaxies. Results. For each galaxy and for each photometric band the GASPHOT catalogs provide the parameters of the Sersic law best-fitting the luminosity profiles. They are: the sky coordinates of the galaxy center (R:A:; 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) giving a global indication of the fit quality. The WINGS-GASPHOT dat...

D'Onofrio, Mauro; Fasano, Gianni; Bettoni, Daniela; Cava, Antonio; Fritz, Jacopo; Gullieuszik, Marco; Kjaergaard, Per; Moretti, Alessia; Moles, Mariano; Omizzolo, Alessandro; Poggianti, Bianca; Valentinuzzi, Tiziano; Varela, Jesus

2014-01-01

4

Hubble Deep Field surface photometry (Fasano+ 1998)  

NASA Astrophysics Data System (ADS)

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 (Couch, 1996, ). 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 Williams et al. (1996, Cat. ) 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 r1/4 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. (2 data files).

Fasano, G.; Filippi, M.; Bertola, F.

1997-11-01

5

Changes on Pluto's Surface Revealed with Long Timebase Photometry  

NASA Astrophysics Data System (ADS)

We are continuing to monitor the long-term photometric behavior of Pluto in order to constrain volatile surface migration. As Pluto passes near the center of the galaxy, the fields are too crowded for normal aperture photometric techniques. We approached this problem with a combination of point-spread function (PSF) photometry and optimal image subtraction (OIS). Our data are from the 0.8-m robotic telescope at Lowell Observatory, the 1-m robotic telescope at New Mexico State Observatory, and the Faulkes 2-m robotic telescope at Siding Spring, part of Las Cumbres Observatory. Our latest results add photometric data up through 2012 to the data collected since discovery. Our new reduction scheme consists of background catalogs, image subtraction using deep templates, and Pluto photometry extraction. We also use the known photometric properties of Charon determined with HST to remove Charon's contribution from old and new data and compare these results with the HST data where Pluto is measured by itself. Data since 2002 show marked departures from the behavior prior to that time. These results provide clear evidence for time evolution of Pluto's surface albedo. We will present these results along with implications for present-day processes that are altering the surface of Pluto. This work also provides crucial insight into the effort required to provide ground-based support observations for the upcoming New Horizons flyby of Pluto in 2015. Support for this work was provided by NASA Planetary Astronomy Program, grant number NNX09AB43G.

George, Erin; Buie, M.

2013-10-01

6

CCD surface photometry of galaxies in the cluster Shapley 1346-30  

Microsoft Academic Search

Multicolour CCD surface photometry has been obtained for seven galaxies in the cluster Shapley 1346-30, viz. IC 4329, IC 4329 A, NGC 5291, NGC 5291 B, NGC 5298, NGC 5298 A and NGC 5302. The data have been reduced via ellipse fitting routines. Intensity profiles are used to clarify some discrepancies in previous morphological classifications. The authors also present colour

P. N. Daly; S. Phillipps; M. J. Disney

1987-01-01

7

Deep near-infrared surface photometry and properties of Local Volume dwarf irregular galaxies  

NASA Astrophysics Data System (ADS)

We present deep H-band surface photometry and analysis of 40 Local Volume galaxies, a sample primarily composed of dwarf irregulars in the Cen A group, obtained using the Infrared Imager and Spectrograph 2 detector at the 3.9-m Anglo-Australian Telescope. We probe to a surface brightness of ˜25 mag arcsec-2, reaching a 40 times lower stellar density than the Two Micron All Sky Survey (2MASS). Employing extremely careful and rigorous cleaning techniques to remove contaminating sources, we perform surface photometry on 33 detected galaxies deriving the observed total magnitude, effective surface brightness and best-fitting Sérsic parameters. We make image quality and surface photometry comparisons to 2MASS and VISTA Hemisphere Survey demonstrating that deep targeted surveys are still the most reliable means of obtaining accurate surface photometry. We investigate the B - H colours with respect to mass for Local Volume galaxies, finding that the colours of dwarf irregulars are significantly varied, eliminating the possibility of using optical-near-infrared colour transformations to facilitate comparison to the more widely available optical data sets. The structure-luminosity relationships are investigated for our `clean' sample of dwarf irregulars. We demonstrate that a significant fraction of the Local Volume dwarf irregular population have underlying structural properties similar to both Local Volume and Virgo cluster dwarf ellipticals. Linear regressions to structure-luminosity relationships for the Local Volume galaxies and Virgo cluster dwarf ellipticals show significant differences in both slope and scatter around the established trend lines, suggesting that environment might regulate the structural scaling relationships of dwarf galaxies in comparison to their more isolated counterparts.

Young, T.; Jerjen, H.; López-Sánchez, Á. R.; Koribalski, B. S.

2014-11-01

8

Planetary surface photometry and imaging: progress and perspectives.  

PubMed

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

Goguen, Jay D

2014-10-01

9

Planetary surface photometry and imaging: progress and perspectives  

NASA Astrophysics Data System (ADS)

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.

Goguen, Jay D.

2014-10-01

10

CCD surface photometry of galaxies in the cluster Shapley 1346-30  

NASA Astrophysics Data System (ADS)

Multicolour CCD surface photometry has been obtained for seven galaxies in the cluster Shapley 1346-30, viz. IC 4329, IC 4329 A, NGC 5291, NGC 5291 B, NGC 5298, NGC 5298 A and NGC 5302. The data have been reduced via ellipse fitting routines. Intensity profiles are used to clarify some discrepancies in previous morphological classifications. The authors also present colour profiles and variations of position angle, eccentricity and centre with isophotal radius.

Daly, P. N.; Phillipps, S.; Disney, M. J.

1987-02-01

11

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

Microsoft Academic Search

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

W. Hofmann; D. Lemke; C. Thum

1977-01-01

12

Disc galaxies with multiple triaxial structures. II. JHK surface photometry and numerical simulations  

E-print Network

We present detailed JHK surface photometry with ellipse fits of 13 galaxies selected from previous optical observations as likely candidates for having a secondary bar or a triaxial bulge within the primary bar. We have found 7 double-barred galaxies, 3 double-barred galaxies with an additional intermediate structure with twisted isophotes, and 3 galaxies with a bar and central twisted isophotes. A global analysis of the structural parameter characteristics in the I- and K-bands is presented. Various numerical models of galaxies with bars within bars are also analysed using the ellipse fitting technique and compared to the observations. A thorough review of the possible hypotheses able to explain this phenomenon is given with emphasis on the most likely ones.

D. Friedli; H. Wozniak; M. Rieke; L. Martinet; P. Bratschi

1996-03-12

13

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

SciTech Connect

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.

Fingerhut, Robin L.; McCall, Marshall L.; Argote, Mauricio [Department of Physics and Astronomy, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3 (Canada); Cluver, Michelle E. [IPAC, California Institute of Technology, MC 220-6, Pasadena, CA 91106 (United States); Nishiyama, Shogo [Department of Astronomy, Kyoto University Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Rekola, Rami T. F. [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, FI-21500 Piikkioe (Finland); Richer, Michael G. [Instituto de Astronomia, Universidad Autonoma de Mexico, P.O. Box 439027, San Diego, CA 92143 (United States); Vaduvescu, Ovidiu [Isaac Newton Group of Telescopes, Apartado 321, E-38700 Santa Cruz de La Palma (Spain); Woudt, Patrick A., E-mail: rfinger@yorku.c, E-mail: mccall@yorku.c, E-mail: argote@yorku.c, E-mail: mcluver@ipac.caltech.ed, E-mail: shogo@kusastro.kyoto-u.ac.j, E-mail: rareko@utu.f, E-mail: richer@astrosen.unam.m, E-mail: ovidiuv@ing.iac.e, E-mail: pwoudt@ast.uct.ac.z [Department of Astronomy, University of Cape Town, Rondebosch 7700 (South Africa)

2010-06-10

14

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

15

UV and Optical Surface Photometry of NGC 1068 from UIT and Ground-Based Observations  

NASA Astrophysics Data System (ADS)

We present a photometric analysis of ultraviolet (UV) and optical image data for NGC 1068. The UV data were obtained by the Ultraviolet Imaging Telescope (UIT) in two bands: far-UV (FUV), lambda_ {eff} ~ 1520 \\ Angstroms, and near-UV (NUV), lambda_ {eff} ~ 2490 \\ Angstroms. Associated optical CCD images in the B and R bandpasses were obtained at KPNO and at Mt. Laguna Observatory of San Diego State University. Using annular aperture photometry and isophotal fitting techniques, we derive structural parameters such as disk scale lengths, central surface brightness, luminosity, and isophotal diameters. The radial brightness profile is best described by two components with a distinct break at r ~ 90('') (6.5 kpc). This break is present in the NUV, B, and R bands, with the NUV bandpass being the most pronounced. Both components are consistent with an exponentially declining light profile, with the outer component (90('') < r < \\ ~ 200('') ) showing a more shallow gradient. Maps of the UV-optical color distribution (muv -- moptical) reveal the dust distribution, the underlying old stellar population and areas of recent massive star formation. The broken circumnuclear ring of luminous knots appears blue in UV-optical colors. However, their FUV -- NUV colors are more complex; exhibiting a range of colors, - 0.5 < FUV -- NUV < +0.5, most likely produced by patchy extinction. These maps also show a uniform red disk at r > 50('') (3.5 kpc) with a NUV -- B color ~ 1.4 mags and a NUV -- R color ~ 2.9 mags.

Roberts, L. J.; Fanelli, M. N.; Neff, S. G.; Smith, E. P.; Cheng, K. P.; Hintzen, P. M. N.; O'Connell, R. W.; Bohlin, R. C.; Roberts, M. S.; Smith, A. M.; Stecher, T. P.

1993-12-01

16

NGC 4314. I - Visible and short-wavelength infrared surface photometry of the nucleus and bar  

NASA Technical Reports Server (NTRS)

BVI (TI CCD) and JHK (University of Texas IR Camera) surface photometry of NGC 4314, an SB (rs)ap anemic spiral with a nuclear ring containing recent star formation, is presented. The shortwave IR (SWIR) frames reveal a nuclear bar of length 2 arcsec at PA of 0 deg. The nuclear ring and associated dust were detected in all SWIR color indices. A nuclear spiral was detected in the visible and SWIR just exterior to the ring. Extremely low-amplitude spiral-shaped deficits were found in the stellar distribution in the SWIR in this same region. These are attributed to dust, since CO is detectable at or near these locations. Average minor-axis profiles show this galaxy to have a nuclear bulge obeying the de Vaucouleurs r exp 1/4 law for values in the range 2-7 arcsec. The extinction and scattering characteristics of dust near the sites of recent star formation in the nuclear ring are discussed.

Benedict, G. F.; Higdon, J. L.; Tollestrup, E. V.; Hahn, J. M.; Harvey, P. M.

1992-01-01

17

Hubble Space Telescope Observations of the CfA Seyfert 2 Galaxies: Near-Infrared Surface Photometry and Nuclear Bars  

Microsoft Academic Search

We present near-infrared J and H surface photometry of 24 of the nearby Seyfert 1.8, 1.9, and 2 galaxies from the CfA Seyfert sample. The excellent angular resolution of the Hubble Space Telescope probes spatial scales as small as tens of parsecs in most of these active galactic nuclei (AGNs) and is sensitive to the presence of nuclear bars and

Paul Martini; Richard W. Pogge; Swara Ravindranath; Jin H. An

2001-01-01

18

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

NASA Technical Reports Server (NTRS)

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.

Yuan, C.; Grosbol, P.

1981-01-01

19

Effect of surface conditions affecting voltage breakdowns  

NASA Astrophysics Data System (ADS)

The maximum power transferred by ion cyclotron range of frequency (ICRF) antennas is dependent on the breakdown threshold when operated at high voltages. The voltage that these antennas can withstand is lowered and hence breakdowns occur due to many factors. The Surface Plasma Arcs by Radiofrequency - Control Study or SPARCS facility has a 0-15kV DC power supply to deliver power to flat cathode surface and semi-spherical anode made of Cu and Al under 10-8-10-6 torr vacuum conditions. The effects of different surface conditions on the breakdown threshold were then investigated. Also, as the ICRF antennas used for heating plasmas may come into contact with contaminants from the plasma, Li was also deposited on the cathode surface through in-situ evaporation coating and its effect on the breakdown threshold was investigated. Results on surface roughness showed no significant dependence of the breakdown threshold on macroscopic surface roughness in the cathode arithmetic roughness range of ˜77-1139nm. Microscopic surface features such as grain boundaries, impurities and imperfections may play a more visible role in affecting the vacuum breakdown.

Flauta, Randolph; Aghazarian, Maro; Caughman, John; Ruzic, David

2008-11-01

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)

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.

Bothun, Gregory D.; Rogers, C.

1992-01-01

21

Optics on a fractal surface and the photometry of the regoliths  

NASA Astrophysics Data System (ADS)

The light scattered by a rough surface is calculated in a model where the surface is simulated by a mathematical fractal of dimension (D(H) between 2 and 3) and fractal density in the projected area towards the observer rho(H) (rho(H) between 0 and 1). The reflectance on such a surface is calculated in the special case of a 'hemispherical' fractal, in both the geometric optics approximation and a more general diffraction regime. By using a two-parameter phase function (single scattering albedo omega-sub-0 and asymmetry parameter g-sub-0), and including multiple scattering, this four-parameter model is found to reproduce within a good accuracy the phase function of several classes of atmosphereless bodies in the solar system, in good agreement with previous photometric models. The main effect of the diffraction is to reduce the width of the opposition surge by roughly a factor of 2. Another prediction of the model is that the single-scattering contribution due to the fractal part of the surface can be reduced, for nonzero phase angle, to an arbitrarily small amount, for high enough fractal dimension and density. This effect could give a new interpretation of the strong opposition effect observed on some objects, and also of the very low brightness of many solar system bodies.

Drossart, P.

1993-05-01

22

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

NASA Technical Reports Server (NTRS)

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.

Noland, M.; Veverka, J.

1977-01-01

23

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

NASA Astrophysics Data System (ADS)

We present near-infrared, H-band (1.65 $() ?m), surface photometry of 174 spiral galaxies in the area of the Pisces-Perseus supercluster. The images, acquired with the ARNICA camera mounted on various telescopes, are used to derive radial profiles of surface brightness, ellipticities, and position angles, together with global parameters such as H-band magnitudes and diameters Radial profiles in tabular form and images FITS files are also available upon request from gmorio@arcetri.astro.it.}. The mean relation between H-band isophotal diameter D_{21.5} and the B-band D25 implies a B-H color of the outer disk bluer than 3.5; moreover, D_{21.5}/D25 depends on (global) color and absolute luminosity. The correlations among the various photometric parameters suggest a ratio between isophotal radius D_{21.5}/2 and disk scale length of ~ m3.5 and a mean disk central brightness ~ meq 17.5 H-mag arcsec^{-2}. We confirm the trend of the concentration index C31$ 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.

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

1999-05-01

24

Dust-corrected surface photometry of M 31 from the Spitzer far infrared observations  

E-print Network

We create a model for recovering the intrinsic, absorption-corrected surface brightness distribution of a galaxy and apply the model to the M31. We construct a galactic model as a superposition of axially symmetric stellar components and a dust disc to analyse the intrinsic absorption efects. Dust column density is assumed to be proportional to the far-infrared flux of the galaxy. Along each line of sight, the observed far-infrared spectral energy distribution is approximated with modified black body functions considering dust components with different temperatures, allowing to determine the temperatures and relative column densities of the dust components. We apply the model to the nearby galaxy M31 using the Spitzer Space Telescope far-infrared observations for mapping dust distribution and temperature. A warm and a cold dust component are distinguished. The temperature of the warm dust in M31 varies between 56 and 60 K and is highest in the spiral arms; the temperature of the cold component is mostly 15-19...

Tempel, Elmo; Tenjes, Peeter; 10.1051/0004-6361/200912186

2009-01-01

25

Configurational Equilibrium of Cracks Affected by Surface Stress and  

E-print Network

Configurational Equilibrium of Cracks Affected by Surface Stress and Crack-Tip Point Load Chien HUIC Remote Loading, Surface Stress and Crack-Tip Load 11 22 2 0 - P R P The Bulk-Surface System Free-Body and Surface Stress The Bulk-Surface System Free-Body Of The "Surface" R 2 2 0 2 0 0 0 062999

Wu, Chien H.

26

How surface damage removal affects fatigue life  

NASA Technical Reports Server (NTRS)

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.

Jeelani, S.; Scott, M. A.

1988-01-01

27

ARCHANGEL: Galaxy Photometry System  

NASA Astrophysics Data System (ADS)

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.

Schombert, James

2011-07-01

28

Galaxy Photometry  

NSDL National Science Digital Library

This activity asks students to observe the images of three spiral galaxies of different surface brightnesses. Each of the loaded images is active in the sense that you can place a rectangular aperture on them and determine the flux. The flux through the aperture equals the galaxy flux + the sky flux. Hence to determine the galaxy flux you need to put an aperture on the sky background (where there is little or no galaxy light) and measure that.

Department, University O.

2005-06-17

29

1.65?m (H-band) surface photometry of galaxies. II. Observations of 297 galaxies with the TIRGO 1.5m telescope.  

NASA Astrophysics Data System (ADS)

We present near-infrared H-band (1.65?m) surface photometry of 297 galaxies (mostly) in the Coma Supercluster obtained with the Arcetri NICMOS3 camera, ARNICA, mounted on the Gornergrat Infrared Telescope. Magnitudes and diameters within the 21.5mag/arcsec^2^ isophote, concentration indices, and total H magnitudes are derived. Combining these observations with those obtained similarly using the Calar Alto telescopes (Paper I, 1996A&AS..120..489G) we find a strong positive correlation between the near-infrared concentration index and the galaxy H-band luminosity, and we analyze the consequent dependence of near-infrared growth-curves on H-band luminosity.

Gavazzi, G.; Pierini, D.; Baffa, C.; Lisi, F.; Hunt, L. K.; Randone, I.; Boselli, A.

1996-12-01

30

1.65 ?m (H-band) surface photometry of galaxies. III. observations of 558 galaxies with the TIRGO 1.5 m telescope  

NASA Astrophysics Data System (ADS)

We present near-infrared H-band (1.65 ?m ) surface photometry of 558 galaxies in the Coma Supercluster and in the Virgo cluster. This data set, obtained with the Arcetri NICMOS3 camera ARNICA mounted on the Gornergrat Infrared Telescope, is aimed at complementing, with observations of mostly early-type objects, our NIR survey of spiral galaxies in these regions, presented in previous papers of this series. Magnitudes at the optical radius, total magnitudes, isophotal radii and light concentration indices are derived. We confirm the existence of a positive correlation between the near-infrared concentration index and the galaxy H-band luminosity Based on observations taken at TIRGO (Gornergrat, Switzerland). TIRGO is operated by CAISMI-CNR, Arcetri, Firenze, Italy. Tables 1 and 2 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

Gavazzi, G.; Franzetti, P.; Scodeggio, M.; Boselli, A.; Pierini, D.; Baffa, C.; Lisi, F.; Hunt, L. K.

2000-02-01

31

Activities affecting surface water resources: A general overview  

SciTech Connect

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.

Not Available

1990-01-01

32

How a Change in Water Phase Affects Surface Temperatures  

NSDL National Science Digital Library

In this problem-based learning (PBL) activity, students take on the role of a student research scientist and explore the role of solar energy in determining climate. Students conduct experiments to observe how a change in water phase affects surface temperatures. Materials required for the investigation include 2 aquariums, dry sand or soil, two heat lamps, and two thermometers.The lesson is supported by teacher notes, answer key, glossary and an appendix with information about using PBL in the classroom. This is the second of three activities in Investigating the Climate System: Energy, a Balancing Act.

33

Galileo photometry of Asteroid 951 Gaspra  

Microsoft Academic Search

The mean photometric properties of Gaspra's surface are derived in terms of Hapke's photometric model by combining earth-based telescopic photometry with Galileo's whole-disk and disk-resolved data. The results are used to estimate fundamental properties, such as the geometric albedo, and to compare surface materials on Gaspra with materials on other planetary surfaces. The photometric parameters and a new shape model

P. Helfenstein; J. Veverka; P. C. Thomas; D. P. Simonelli; P. Lee; K. Klaasen; T. V. Johnson; H. Breneman; J. W. Head; S. Murchie

1994-01-01

34

Internal standard flame photometry  

Microsoft Academic Search

The author's colour wedge photometer has been used to study some aspects of flame photometry as applied to chemical analysis. It has been shown that convenient calibration curves may be obtained with this method. Studies have also been made of the effect of foreign substances and of the optimum operating conditions of the flame.

E G Walsh

1952-01-01

35

Exploration mode affects visuohaptic integration of surface orientation.  

PubMed

We experience the world mostly in a multisensory fashion using a combination of all of our senses. Depending on the modality we can select different exploration strategies for extracting perceptual information. For instance, using touch we can enclose an object in our hand to explore parts of the object in parallel. Alternatively, we can trace the object with a single finger to explore its parts in a serial fashion. In this study we investigated whether the exploration mode (parallel vs. serial) affects the way sensory signals are combined. To this end, participants visually and haptically explored surfaces that varied in roll angle and indicated which side of the surface was perceived as higher. In Experiment 1, the exploration mode was the same for both modalities (i.e., both parallel or both serial). In Experiment 2, we introduced a difference in exploration mode between the two modalities (visual exploration was parallel while haptic exploration was serial or vice versa). The results showed that visual and haptic signals were combined in a statistically optimal fashion only when the exploration modes were the same. In case of an asymmetry in the exploration modes across modalities, integration was suboptimal. This indicates that spatial-temporal discrepancies in the acquisition of information in the two senses (i.e., haptic and visual) can lead to the breakdown of sensory integration. PMID:25413627

Plaisier, Myrthe A; van Dam, Loes C J; Glowania, Catharina; Ernst, Marc O

2014-01-01

36

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

SciTech Connect

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.

Sonnenfeld, Alessandro; Suyu, Sherry H.; Treu, Tommaso [Physics Department, University of California, Santa Barbara, CA 93106 (United States); Gavazzi, Raphaël [Institut d'Astrophysique de Paris, UMR7095 CNRS-Université Pierre et Marie Curie, 98bis bd Arago, F-75014 Paris (France); Marshall, Philip J., E-mail: sonnen@physics.ucsb.edu [Department of Physics, University of Oxford, Keble Road, Oxford, OX1 3RH (United Kingdom)

2013-11-10

37

SURFACE ENERGY BALANCE AFFECTS GAS EXCHANGE OF THREE SHRUB SPECIES  

Microsoft Academic Search

We investigated the energy balance of vegetative and nonvegetative surfaces and gas exchange for 3 shrub species growing over each surface. During a 1 -week period, incoming short-wave radiation, surface and soil tempera- ture, and soil heat flux for turf and pine-bark mulch surfaces were gathered. Air temperature and relative humidity at 2 heights over each surface were also measured.

Thayne Montague; Roger Kjelgren; Larry Rupp

38

Surface photometry of edge-on spiral galaxies. IV - The distribution of light, colour, and mass in the disk and spheroid of NGC 7814  

NASA Astrophysics Data System (ADS)

We present three-colour surface photometry of the edge-on spiral galaxy NGC 7814. The light distribution of this galaxy is dominated by its spheroid. We fit the light distribution of the spheroid with high accuracy (0.1-0.2 mag arc s-2) using a model in which the radial dependence is an R1/4--law and the isophotes at all radii and in all three colours have an axis ratio of about 0.57. The colours of the spheroid become progressively bluer with increasing radius and the isochromes are closely similar in shape to the isophotes. The colour gradient results, presumably, from a decrease in the mean heavy element abundance with increasing radius. Subtraction of the light predicted by the spheroid model from the observed total light distributions reveals the residual disk. This has colours similar to those of an old disk population and it has been fitted with the disk model proposed in Paper I of this series. The disk involves only a few percent of the total mass of NGC 7814, 50 that the spheroid dominates the gravitational field. This is presumably the reason that the spheroid of NGC 7814 is not flattened in its outer parts (as is the case in NGC 4565, 891, and 4013 described in Papers 1-111) and why the dust lane and the old stellar disk are much thicker in the z-direction than is the case in the later type spirals. The sum of our model disk and spheroid reproduces the observed surface brightness distributions everywhere - except near the dust lane - to 0.2 mag arc s-2 or better. There are no appreciable populations with flattenings intermediate between those of the disk and spheroid. This fact, together with the - observed similarity of isochromes and isophotes and the uniformity of isophotal axis ratios in the spheroid present difficulties - for models in which galactic halos form by a gaseous condensation process. We report Westerbork H I synthesis observations of NGC 7814. These observations show that the H I is located in a flat, thin disk out to 4'.5-5', a radius coinciding with the galaxy's optical extent. There may be a warp on the SE side beyond this radius. The rotation curve is flat from 0;75 galactocentric radius out to at least 4'.5-5' at 225 ± 15 km s-1. The total mass within this radius (22 kpc) is 2 1011 Msun km s-1 assuming a distance of 15 Mpc. Of this mass ˜0.5% is in the form of H I and ˜2% in the form of disk stars. We estimate that the mass-to-light ratio in the spheroid increases by an order of magnitude from 14 to 160 Msun/Lsun over the range 3-22 kpc in galactocentric distance. We also show that this mass and luminosity distribution in the spheroid combined with the stellar velocity field (Kormendy and Illingworth, 1981) predicts that the velocity dispersion is roughly isotropic in the centre and at greater distances from the centre becomes increasingly anisotropic, the radial velocity dispersion increasing with galactocentric distance. We infer from the abundance structure of the spheroid that metal-rich halo stars formed in the protogalaxy in locations such that they had larger binding energy than metal-poor ones. If the dark matter consists of faint stars or black dwarfs that formed together with luminous halo stars, the observed abundance gradient and the M/L gradient may be causally related.

van der Kruit, P. C.; Searle, L.

1982-06-01

39

Third Workshop on Photometry  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

40

The 2060 Chiron: CCD photometry  

NASA Technical Reports Server (NTRS)

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.

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

1987-01-01

41

Football Playing Surface and Shoe Design Affect Rotational Traction  

Microsoft Academic Search

Background: High rotational traction between football shoes and the playing surface may be a potential mechanism of injury for the lower extremity.Hypothesis: Rotational traction at the shoe-surface interface depends on shoe design and surface type.Study Design: Controlled laboratory study.Methods: A mobile testing apparatus with a compliant ankle was used to apply rotations and measure the torque at the shoe-surface interface.

Mark R. Villwock; Eric G. Meyer; John W. Powell; Amy J. Fouty; Roger C. Haut

2009-01-01

42

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

PubMed

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

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

2008-10-01

43

Plant surface wax affects parasitoid's response to host footprints  

NASA Astrophysics Data System (ADS)

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.

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

2008-10-01

44

How strain affects the reactivity of surface metal oxide catalysts.  

PubMed

Highly dispersed molybdenum oxide supported on mesoporous silica SBA-15 has been prepared by anion exchange resulting in a series of catalysts with changing Mo densities (0.2-2.5?Mo atoms?nm(-2) ). X-ray absorption, UV/Vis, Raman, and IR spectroscopy indicate that doubly anchored tetrahedral dioxo MoO4 units are the major surface species at all loadings. Higher reducibility at loadings close to the monolayer measured by temperature-programmed reduction and a steep increase in the catalytic activity observed in metathesis of propene and oxidative dehydrogenation of propane at 8?% of Mo loading are attributed to frustration of Mo oxide surface species and lateral interactions. Based on DFT calculations, NEXAFS spectra at the O-K-edge at high Mo loadings are explained by distorted MoO4 complexes. Limited availability of anchor silanol groups at high loadings forces the MoO4 groups to form more strained configurations. The occurrence of strain is linked to the increase in reactivity. PMID:24259425

Amakawa, Kazuhiko; Sun, Lili; Guo, Chunsheng; Hävecker, Michael; Kube, Pierre; Wachs, Israel E; Lwin, Soe; Frenkel, Anatoly I; Patlolla, Anitha; Hermann, Klaus; Schlögl, Robert; Trunschke, Annette

2013-12-16

45

Asteroid photometry achieved with small telescopes  

NASA Astrophysics Data System (ADS)

Despite very valuable information from space missions (NEAR, Hayabusa,...) extremely important data about asteroids are provided by photometric observations from ground-based telescopes. Because observations are so time-consuming, small telescopes (<2 m) at professional observatories are mostly used. The Community of amateur astronomers also perform extraordinary precise work using even smaller telescopes (>0.2 m). The results of short-term photometry are the rotational period and the amplitude of changes of brightness in a variety of solar phase angles. Medium-term photometry is able to cover eclipses/occultations of binary asteroids very well and to determine the parameters of the primary and the satellite. Long-term photometry detects amplitude variations in different apparitions, determines the direction of rotation axes and the sense of rotation and helps to create a 3D model of the asteroid's shape. By using photometric data from a wider time interval we can study the thermal YORP effect, which affects the trajectory and rotation of asteroids (mainly NEAs). It can be used also in the photometric survey of the paired asteroids.

Husárik, M.

2014-03-01

46

Aerodynamic and surface resistances affecting energy transport in a sparse crop  

Microsoft Academic Search

Ham, J.M. and Heilman, J.L., 1991. Aerodynamic and surface resistances affecting energy transport in a sparse crop. Agric, For. Meteorol., 53: 267-284. Aerodynamic and surface properties of the soil and canopy affect energy transport within sparse crops. A study was conducted with cotton ( Gossypium hirsutum L. ) to evaluate the feasibility of using both surface and within-canopy resistances to

J. M. Ham; J. L. Heilman

1991-01-01

47

Factors Affecting Survival of Bacteriophage on Tomato Leaf Surfaces?  

PubMed Central

The ability of bacteriophage to persist in the phyllosphere for extended periods is limited by many factors, including sunlight irradiation, especially in the UV zone, temperature, desiccation, and exposure to copper bactericides. The effects of these factors on persistence of phage and formulated phage (phage mixed with skim milk) were evaluated. In field studies, copper caused significant phage reduction if applied on the day of phage application but not if applied 4 or 7 days in advance. Sunlight UV was evaluated for detrimental effects on phage survival on tomato foliage in the field. Phage was applied in the early morning, midmorning, early afternoon, and late evening, while UVA plus UVB irradiation and phage populations were monitored. The intensity of UV irradiation positively correlated with phage population decline. The protective formulation reduced the UV effect. In order to demonstrate direct effects of UV, phage suspensions were exposed to UV irradiation and assayed for effectiveness against bacterial spot of tomato. UV significantly reduced phage ability to control bacterial spot. Ambient temperature had a pronounced effect on nonformulated phage but not on formulated phages. The effects of desiccation and fluorescent light illumination on phage were investigated. Desiccation caused a significant but only slight reduction in phage populations after 60 days, whereas fluorescent light eliminated phages within 2 weeks. The protective formulation eliminated the reduction caused by both of these factors. Phage persistence was dramatically affected by UV, while the other factors had less pronounced effects. Formulated phage reduced deleterious effects of the studied environmental factors. PMID:17259361

Iriarte, F. B.; Balogh, B.; Momol, M. T.; Smith, L. M.; Wilson, M.; Jones, J. B.

2007-01-01

48

Precision Photometry for Planetary Transits  

NASA Astrophysics Data System (ADS)

This paper reviews the state of the art in follow-up photometry for planetary transit searches. Three topics are discussed: (1) Photometric monitoring of planets discovered by radial velocity to detect possible transits (2) Follow-up photometry of candidates from photometric transit search to weed out eclipsing binaries and false positives (3) High-precision light curves of known transiting planets to increase the accuracy on the planet parameters.

Pont, F.; Moutou, C.

2007-07-01

49

Nanoparticles affect the survival of bacteria on leaf surfaces.  

PubMed

The increasing presence of nanomaterial and nanoproducts makes it imperative to learn more about the associated impacts of these materials on human health and the environment. In this study, the effect of the nanomaterial TiO2 on the phyllosphere microbial community was investigated. Analysis results by PCR-denaturing gradient gel electrophoresis revealed a TiO2-induced change in the community structure of microorganisms. An epiphytic bacterium, Bacillus cereus 905, was chosen to study the role of the superoxide dismutase-encoding genes, sodA-1 and sodA-2, and its survival from TiO2 photocatalysis. Our results showed that the expression of sodA-1 and sodA-2 was induced by photocatalytic oxidation, with a higher induction observed in sodA-2. In addition, compared with wild-type B. cereus 905, a reduced bacterial population was observed in a sodA-1 and sodA-2 double deletion mutant strain KOS on a cucumber leaf surface sprayed with TiO2. Because the phyllosphere is considered as one of the major habitats for microorganisms, and substantial areas of the earth are covered with leaves, the results of this work provides information of the potential impact of photocatalytic nanomaterial in the environment. PMID:19573199

Wang, Shuang; Chang, Li-Yan; Wang, Yong-Jun; Wang, Qi; Yang, Ching-Hong; Mei, Ru-Hong

2009-05-01

50

How Waves Affect the Distribution of Particles that Float on a Liquid Surface P. Denissenko,1  

E-print Network

How Waves Affect the Distribution of Particles that Float on a Liquid Surface P. Denissenko,1 G of particles that float on a liquid surface. We show that clustering of small particles in a standing wave,9,10]. Here we study the effect of clustering by waves on a liquid surface. In a single-mode standing wave

Falkovich, Gregory

51

Detection by Transit Photometry  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

52

PHOTOM: Photometry of digitized images  

NASA Astrophysics Data System (ADS)

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).

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

2014-05-01

53

Second Workshop on Improvements to Photometry  

NASA Technical Reports Server (NTRS)

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.

Borucki, William J. (editor)

1988-01-01

54

NAAP Variable Star Photometry 1/12 Variable Star Photometry Student Guide  

E-print Network

Name: NAAP ­ Variable Star Photometry 1/12 Variable Star Photometry ­ Student Guide Background) ___________________________________________________________________________ #12;Name: NAAP ­ Variable Star Photometry 2/12 Question 3: A CCD has a greatest possible pixel value. This process of alignment is known as registration. #12;Name: NAAP ­ Variable Star Photometry 3

Farritor, Shane

55

CCD photometry of 625 Xenia  

NASA Astrophysics Data System (ADS)

615 Xenia was observed for eight nights using CCD photometry during the months of April and May 1998. The period of rotation was 21.101 ± 0.032 hours, and the lightcurve had amplitude of 0.50 ± 0.05 magnitude.

Worman, W. E.; Fieber, Sherry; Creason, Mary A.

56

Voyager photometry of Io  

SciTech Connect

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.

Simonelli, D.P.

1987-01-01

57

How impregnation with boron compounds affects the surface hardness of some varnishes  

Microsoft Academic Search

Purpose – The purpose of this paper is to investigate how impregnation with boron compounds affects the surface hardness of varnished wood materials. Design\\/methodology\\/approach – Test samples were prepared from Scotch pine, Oriental spruce, and Uludag fir, which met the requirements of ASTM D 358.These samples were impregnated with boric acid (Ba) and borax (Bx) using a vacuum technique, according

M. Atar; H. Keskin; S. Korkut; D. S. Korkut

2011-01-01

58

Photometry of meteorites  

NASA Astrophysics Data System (ADS)

We have measured the bi-directional reflectance phase function on selected meteorite samples (1 howardite, 1 eucrite, 1 diogenite, Orgeuil (CI), Tagish Lake (CC), Allende (CV), Lunar meteorite (MAC 88105), Forest Vale (H4)) covering part of the geochemical and petrologic diversity expected for asteroid surfaces. Samples were measured as powders, for which we achieved reflectance measurements from phase angles down to 3°, and up to 150°, at five different wavelengths covering the VIS-NIR spectral region. The data were fitted by the photometric model of Hapke (Hapke, B. [1993]. Theory of reflectance and emittance spectroscopy. Cambridge University Press, Cambridge). The physical sense of the retrieved Hapke’s parameters seems unclear but they permit to interpolate the data to any observation geometry. Strong opposition effects were observed for all samples. The absolute intensity of this effect appears moderately variable among our sample suite, and is not correlated with the average sample reflectance. We interpret this observation as Shadow-Hiding Opposition Effect (SHOE). In the case of samples presenting intense absorption bands (the Fe crystal field band at 1 ?m of HED and the ordinary chondrite), we observe significant dependence of band depth to phase angle, up to 70°, even for moderate variation of phase angle. In addition, a general trend of spectral reddening with phase angle is observed. This reddening, linear with phase angle, is present in all meteorites studied. This behavior is not predicted by classical radiative theories. We propose that small-scale roughness (of the order of or below the wavelength) may induce such a behavior.

Beck, P.; Pommerol, A.; Thomas, N.; Schmitt, B.; Moynier, F.; Barrat, J.-A.

2012-03-01

59

Nanoscale topographic changes on sterilized glass surfaces affect cell adhesion and spreading.  

PubMed

Producing sterile glass surfaces is of great importance for a wide range of laboratory and medical applications, including in vitro cell culture and tissue engineering. However, sterilization may change the surface properties of glass and thereby affect its use for medical applications, for instance as a substrate for culturing cells. To investigate potential effects of sterilization on glass surface topography, borosilicate glass coverslips were left untreated or subjected to several common sterilization procedures, including low-temperature plasma gas, gamma irradiation and steam. Imaging by atomic force microscopy demonstrated that the surface of untreated borosilicate coverslips features a complex landscape of microislands ranging from 1000 to 3000 nm in diameter and 1 to 3 nm in height. Steam treatment completely removes these microislands, producing a nanosmooth glass surface. In contrast, plasma treatment partially degrades the microisland structure, while gamma irradiation has no effect on microisland topography. To test for possible effects of the nanotopographic structures on cell adhesion, human gingival fibroblasts were seeded on untreated or sterilized glass surfaces. Analyzing fibroblast adhesion 3, 6, and 24 h after cell seeding revealed significant differences in cell attachment and spreading depending on the sterilization method applied. Furthermore, single-cell force spectroscopy revealed a connection between the nanotopographic landscape of glass and the formation of cellular adhesion forces, indicating that fibroblasts generally adhere weakly to nanosmooth but strongly to nanorough glass surfaces. Nanotopographic changes induced by different sterilization methods may therefore need to be considered when preparing sterile glass surfaces for cell culture or biomedical applications. PMID:24027204

Wittenburg, Gretel; Lauer, Günter; Oswald, Steffen; Labudde, Dirk; Franz, Clemens M

2014-08-01

60

CCD surface photometry of IC 2220  

Microsoft Academic Search

BVRI color-difference measurements are reported for the unusual bipolar reflection nebula IC 2220 which surrounds an early-M giant. The data were obtained through BVRI imaging with a CCD detector. Analysis of the color difference between the nebula and the illuminating star HR 3126 indicates that the nebular dust, having formed in the outflow from the star, is similar to average

Adolf N. Witt; C. Rogers

1991-01-01

61

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

PubMed

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

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

2012-12-01

62

Superfast Photometry with MANIA Complex  

NASA Astrophysics Data System (ADS)

We present a hard/software MANIA complex for carrying out superfast photometry. A new type of ``time-code'' converter ``Quantochron'' allows us to measure arrival times of photons registered by a photodetector with time resolutions up to 20 nsec in 2(16) channels (space, colors, polarization, etc.) simultaneously. Special software was developed to investigate variability on a time scale of 2times 10(-8) - 10(3) sec by statistical analysis of the time interval distribution between detected photons and ``classical'' light curves. The results of some observations are presented.

Shvartsman, V. F.; Bernstein, I. N.; Beskin, G. M.; Komarova, V. N.; Neizvestny, S. I.; Plokhotnichenko, V. L.; Popova, M. Yu.; Zhuravkov, A. V.

63

Photometry of astrometric reference stars  

NASA Technical Reports Server (NTRS)

UBVRI, DDO, and uvby, H-beta photometry of astrometric reference stars is presented. Spectral types and luminosity classifications made from the colors are used to determine their spectroscopic parallaxes. In this paper, colors for 309 stars in 25 regions are given, and classifications for 210 stars have been made. These stars form reference frames in the Allegheny Observatory Multichannel Astrometric Photometer astrometric program, and in the Praesepe cluster reduced by Russell (1976). It is found that the present photometric spectral types are reliable to within 2.5 spectral subclasses.

Castelaz, Michael W.; Persinger, Tim; Stein, John W.; Prosser, James; Powell, Harry D.

1991-01-01

64

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

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

65

The Panchromatic Hubble Andromeda Treasury. X. Ultraviolet to Infrared Photometry of 117 Million Equidistant Stars  

NASA Astrophysics Data System (ADS)

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.

Williams, Benjamin F.; Lang, Dustin; Dalcanton, Julianne J.; Dolphin, Andrew E.; Weisz, Daniel R.; Bell, Eric F.; Bianchi, Luciana; Byler, Nell; Gilbert, Karoline M.; Girardi, Léo; Gordon, Karl; Gregersen, Dylan; Johnson, L. C.; Kalirai, Jason; Lauer, Tod R.; Monachesi, Antonela; Rosenfield, Philip; Seth, Anil; Skillman, Eva

2014-11-01

66

Fast photometry with small telescopes  

NASA Astrophysics Data System (ADS)

Facility instruments on major telescopes rarely provide photometry on timescales into the sub-second range. The development of dedicated high-time resolution detectors that could be attached as guest instruments was therefore natural to follow up with optical observations on many highly time variable astronomical objects. Such sources were often discovered first in the radio range (e.g. pulsars, quasars) or with X- and gamma-ray satellites (X-ray binaries, cataclysmic variables, gamma-ray bursts). Although telescopes in the 4 - 8m class would be nice to have for high-time resolution astronomy (HTRA) the access is often oversubscribed. Many currently active HTRA instruments were started on smaller telescopes in the 1-3m class, which provide the flexibility and observation time needed for the observation of highly variable stars. We describe the basic detector types, i.e. fast imaging or photon counting, and current projects. Based on our experience with the fast timing photo-polarimeter OPTIMA (Optical Timing Analyzer), we review some observational constraints on meter-class telescopes. We demonstrate the 'scientific power' of very fast photometry, done with OPTIMA and similar systems on small telescopes, with selected results for a black hole binary, an optical transient magnetar, and the Crab pulsar. %

Kanbach, G.; Rau, A.; S?owikowska, A.

2014-03-01

67

CHARACTERIZATION OF SLOAN DIGITAL SKY SURVEY STELLAR PHOTOMETRY  

SciTech Connect

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.

Fukugita, Masataka [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 2778582 (Japan); Yasuda, Naoki; Doi, Mamoru [Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 2778583 (Japan); Gunn, James E. [Princeton University Observatory, Princeton, NJ 08544 (United States); York, Donald G. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

2011-02-15

68

Kir2.4 Surface Expression and Basal Current Are Affected by Heterotrimeric G-Proteins*  

PubMed Central

Kir2.4, a strongly rectifying potassium channel that is localized to neurons and is especially abundant in retina, was fished with yeast two-hybrid screen using a constitutively active G?o1. Here, we wished to determine whether and how G?o affects this channel. Using transfected HEK 293 cells and retinal tissue, we showed that Kir2.4 interacts with G?o, and this interaction is stronger with the GDP-bound form of G?o. Using two-electrode voltage clamp, we recorded from oocytes that were injected with Kir2.4 mRNA and a combination of G-protein subunit mRNAs. We found that the wild type and the inactive mutant of G?o reduce the Kir2.4 basal current, whereas the active mutant has little effect. Other pertussis-sensitive G? subunits also reduce this current, whereas G?s increases it. G?? increases the current, whereas m-phosducin, which binds G?? without affecting the state of G?, reduces it. We then tested the effect of G-protein subunits on the surface expression of the channel fused to cerulean by imaging the plasma membranes of the oocytes. We found that the surface expression is affected, with effects paralleling those seen with the basal current. This suggests that the observed effects on the current are mainly indirect and are due to surface expression. Similar results were obtained in transfected HEK cells. Moreover, we show that in retinal ON bipolar cells lacking G?3, localization of Kir2.4 in the dendritic tips is reduced. We conclude that G?? targets Kir2.4 to the plasma membrane, and G?o slows this down by binding G??. PMID:23339194

Sulaiman, Pyroja; Xu, Ying; Fina, Marie E.; Tummala, Shanti R.; Ramakrishnan, Hariharasubramanian; Dhingra, Anuradha; Vardi, Noga

2013-01-01

69

Inhibition of cell surface export of group A streptococcal anchorless surface dehydrogenase affects bacterial adherence and antiphagocytic properties.  

PubMed

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 ((337)IVLVGLVMLLLS(348)) was added at the 3' end of the sdh gene, successfully creating a viable mutant strain (M1-SDH(HBtail)). In this mutant strain, the SDH(HBtail) protein was not secreted in the medium but was retained in the cytoplasm and to some extent trapped within the cell wall. Hence, SDH(HBtail) was not displayed on the GAS surface. The mutant strain, M1-SDH(HBtail), grew at the same rate as the wild-type strain. The SDH(HBtail) 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-SDH(HBtail), 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

Boël, Grégory; Jin, Hong; Pancholi, Vijay

2005-10-01

70

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

PubMed Central

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 (?=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

Turgut, Sedanur; Ayaz, Elif Aydogan; Korkmaz, Fatih Mehmet; Ulusoy, K?vanc Utku; Bagis, Yildirim Hakan

2014-01-01

71

From Spitzer Galaxy Photometry to Tully-Fisher Distances  

E-print Network

This paper involves a data release of the observational campaign: Cosmicflows with Spitzer (CFS). Surface photometry of the 1270 galaxies constituting the survey is presented. An additional ~ 400 galaxies from various other Spitzer surveys are also analyzed. CFS complements the Spitzer Survey of Stellar Structure in Galaxies, that provides photometry for an additional 2352 galaxies, by extending observations to low galactic latitudes (|b|calibrators, selected in K band, of the Tully-Fisher relation. The addition of new calibrators demonstrate the robustness of the previously released calibration. Our estimate of the Hubble constant using supernova host galaxies is unchanged, H0 = 75.2 +/- 3.3 km/s/Mpc. Distance-derived radial peculiar velocities, for the 1935 galaxies with all the available parameters, will be incorporated into a new data release of the Cosmicflows project. The size of the previous catalog will be increased by 20%, including spatial regions close to t...

Sorce, J G; Courtois, H M; Jarrett, T H; Neill, J D; Shaya, E J

2014-01-01

72

Sea-surface temperature affects breeding density of an avian rocky intertidal predator, the black oystercatcher Haematopus bachmani  

E-print Network

Sea-surface temperature affects breeding density of an avian rocky intertidal predator, the black Rocky intertidal Sea-surface temperature Data collected in ten years (2003­2012) on Triangle Island oystercatchers (Haematopus bachmani) declines with increasing spring sea-surface temperature. In all ten years

73

Noise characteristics of LCOGT time series photometry  

NASA Astrophysics Data System (ADS)

The Las Cumbres Observatory Global Telescope (LCOGT) facility consists of a network of robotic telescopes located at multiple sites in both the northern and southern hemispheres. We have deployed and commissioned nine 1.0m telescopes. Eight of these are distributed longitudinally at three sites to provide continuous night-time coverage in the south. LCOGT's unique capabilities can contribute to a wide range of research in the field of time-domain astronomy. To ensure optimal data quality for individual as well as combined multi-telescope time series, it is essential that we understand and correct - whenever possible - the instrument systematics affecting LCOGT network observations. We identify physical sources of noise present in LCOGT 1.0m photometry, and we use singular value decomposition (SVD) to filter correlated noise patterns common to an ensemble of stars in a given time series data set. We quantify and compare the levels of uncorrelated and correlated noise before and after SVD filtering using power spectral analysis. Finally, we discuss the properties of and methods to reduce any remaining post-SVD red noise that is due to instrumental systematics.

Dragomir, Diana; Brown, T. M.

2014-01-01

74

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

NASA Astrophysics Data System (ADS)

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 (?= 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.

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

2011-12-01

75

Meteor44 Video Meteor Photometry  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

76

Sorption processes affecting arsenic solubility in oxidized surface sediments from Tulare Lake Bed, California  

USGS Publications Warehouse

Elevated concentrations of arsenic (As) in shallow groundwater in Tulare Basin pose an environmental risk because of the carcinogenic properties of As and the potential for its migration to deep aquifers that could serve as a future drinking water source. Adsorption and desorption are hypothesized to be the major processes controlling As solubility in oxidized surface sediments where arsenate [As(V)] is dominant. This study examined the relationship between sorption processes and arsenic solubility in shallow sediments from the dry Tulare Lake bed by determining sorption isotherms, pH effect on solubility, and desorption-readsorption behavior (hysteresis), and by using a surface complexation model to describe sorption. The sediments showed a high capacity to adsorb As(V). Estimates of the maximum adsorption capacity were 92 mg As kg- 1 at pH 7.5 and 70 mg As kg- 1 at pH 8.5 obtained using the Langmuir adsorption isotherm. Soluble arsenic [> 97% As(V)] did not increase dramatically until above pH 10. In the native pH range (7.5-8.5), soluble As concentrations were close to the lowest, indicating that As was strongly retained on the sediment. A surface complexation model, the constant capacitance model, was able to provide a simultaneous fit to both adsorption isotherms (pH 7.5 and 8.5) and the adsorption envelope (pH effect on soluble As), although the data ranges are one order of magnitude different. A hysteresis phenomenon between As adsorbed on the sediment and As in solution phase was observed in the desorption-readsorption processes and differs from conventional hysteresis observed in adsorption-desorption processes. The cause is most likely due to modification of adsorbent surfaces in sediment samples upon extensive extractions (or desorption). The significance of the hysteresis phenomenon in affecting As solubility and mobility may be better understood by further microscopic studies of As interaction mechanisms with sediments subjected to extensive leaching in natural environments. ?? 2006 Elsevier B.V. All rights reserved.

Gao, S.; Goldberg, S.; Herbel, M.J.; Chalmers, A.T.; Fujii, R.; Tanji, K.K.

2006-01-01

77

Improving Kepler Pipeline Sensitivity with Pixel Response Function Photometry.  

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

78

Surface loading affects internal pressure source characteristics derived from volcano deformation signals  

NASA Astrophysics Data System (ADS)

Deformation of the Earth's surface provides critical information about the migration of material beneath a volcano. The resulting displacements, recorded by geodetic techniques such as GPS or InSAR, are used to infer characteristics of the volcanic plumbing system which are critical for hazard mitigation in volcanic regions. Given some deformation data, we search for the source model that explains the data best. Discussions of the results usually focus on the validity of the chosen model and the underlying assumptions regarding crustal composition, e.g. the level of inhomogeneity, elastic versus plastic deformation, thermal effects, depth vs. volume trade offs of the applied analytical models, or the (in-)compressibility of materials. Surface loads such as lava flows, however, provide an additional source of deformation. The initial elastic response due to a load on the surface of the Earth is followed by a visco-elastic response of the ductile crust below the uppermost elastic layer. Thus, a deformation signal recorded in the vicinity of a volcano is often composed of at least two contributors: an internal pressure source (the magma chamber) and a surface load (e.g., a composition of previously erupted lava flows) - at the extreme the volcanic edifice and its glaciers. A test case for a circular lava flow on top of a deflating magma chamber shows that the crust will adjust to the load towards final relaxed response. During this relaxation process gradual subsidence occurs that may mistakenly be interpreted as due to pressure decrease in a magma chamber since the deformation pattern of both processes are very similar. This poses a problem when characteristics of a magma chamber are to be derived. Based on the ratio of horizontal and vertical displacement and a combination of model results (Green's functions and Mogi model), we can estimate the composition of observed deformation signals. This method is applied to the Icelandic volcano Mt. Hekla where we investigate InSAR observations prior to the Hekla 2000 eruption that show circular pattern of near field subsidence and far field inflation. We compare these data to the deformation pattern expected from pressure changes in a hypothetical, shallow magma reservoir. We estimate surface loading at the volcano to account for a displacement of 13.5mm-yr based on a comparison of expected Mogi source and observed InSAR line of sight velocity. From this we estimate an effective relaxation time of tr = 100yrs for this region. We infer an elastic plate thickness of H = 3.5km which controls the 15 - 20km radius of subsidence. We find that surface load signals in volcanic regions affect magmatic source model estimates significantly ; to the point of changing the preferred source model. This effect should be considered in virtually any volcanic region that shows lava flow emplacement, glacier dynamics, or sudden load removal (i.e., lateral blasts). Deformation data that remains uncorrected will most likely result in an overestimation of depth and volume of a magma reservoir. We find that the ratio of displacements aids the identification of composite signals and suggest that the ratio for GPS data be employed more rigorously in future studies since this allows volume independent source depth estimates.

Grapenthin, Ronni; Sigmundsson, Freysteinn; Ofeigsson, Benedikt; Sturkell, Erik

2010-05-01

79

Detection of Terrestrial Planets Using Transit Photometry  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

80

Photometry Studies of Asteroids and Variable Stars  

NASA Astrophysics Data System (ADS)

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.

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

81

Distant Comets Photometry and Dust Modeling  

NASA Astrophysics Data System (ADS)

Several comets have been observed to develop coma on their in-bound leg at heliocentric distances from 5.84 to 11.49 AU. We will present the observational evidence for their activity and propose an explanation based on experiments carried out on amorphous, gas-laden ice samples that are 0.1 to 100 microns thick and formed by flowing water vapor and CO onto a cold surface. The considerable gas emission occurs when the amorphous ice anneals before 135K, where it transforms into a crystalline structure. This activity was found experimentally to be associated with gas release during annealing of the gas-laden amorphous ice. We observed and measured optical CCD photometry for two short-period and five long-period, dynamically new comets, that have enter the inner solar system directly from the Oort cloud for the first time. All of these comets have been observed pre-perihelion. Observations were done with the University of Hawaii 2.2-m telescope on Mauna Kea with the Tektronix 2x2K CCD camera through the Kron-Cousins B, V, R, I filter system. In order to observationally distinguish the physical causes of activity, not only is it important to observe comets at large heliocentric distances, but also those that are dynamically new and on the in-bound leg of their orbits at distances beyond where the amorphous to crystalline ice phase transition can occur. This research includes observations of the level of nucleus activity as a function of distance. We also would like to present Finson-Probstein (FP) dust modeling investigation on select comets. From the FP dust modeling of a cometary tail we can determine three basic parameters: the dust production rate, the particle distribution, and the emission velocity of the grains.

Pittichova, Jana; Meech, K. J.; Bar-Nun, A.; Notesco, G.

2008-09-01

82

CLEA: Photoelectric Photometry of the Pleiades  

NSDL National Science Digital Library

This lab is designed to familiarize students with the technique of photoelectric filter photometry and counting statistics. The software for this exercise puts students in control of a computer-controlled telescope with sidereal tracking. It illustrates the use of equatorial coordinates for finding stars in a cluster and introduces the use of H-R diagrams for analyzing the age and distance of clusters. A student guide supplied with the software describes how to use B and V photometry of cluster members to plot an H-R diagram of the Pleiades and to determine its distance. This is part of a larger collection of simulations, Project CLEA.

Marschall, Laurence; Snyder, Glenn; Cooper, P. R.; Hayden, Michael; Good, Rhonda

2008-12-15

83

Subtle changes in surface chemistry affect embryoid body cell differentiation: lessons learnt from surface-bound amine density gradients.  

PubMed

Advanced approaches to direct the differentiation of embryonic stem cells are highly sought after. The surface-bound chemical gradient format is a powerful screening approach that can be deployed to study changes in stem cell behavior as a function of subtle changes in surface chemistry. Here, we investigate the spontaneous differentiation of cells derived from differentiating mouse embryoid body (mEB) cells into endoderm, mesoderm, and ectoderm following culture on surface-bound gradients of chemical functional groups in the absence of differentiation-biasing bioactive factors. Gradients were created using a diffusion-controlled plasma polymerization technique. The generated coating ranged from hydrophobic 1,7-octadiene (OD) plasma polymer at one end of the gradient to a more hydrophilic allylamine (AA) plasma polymer on the opposite end. The gradient surface was divided into seven equal regions of progressively increasing AA plasma polymer content and mEB cell response within these regions was compared. Cells adhered preferentially to the central regions of the gradient; however, cell proliferation increased toward AA-plasma-polymer-rich end of the gradient. Variation in the expression of germ layer markers was noted across the gradient surface. High AA:OD plasma polymer ratios triggered cell differentiation toward both mesoderm and ectoderm. Expression of tissue-specific markers, in particular, KRT18, AFP, and TNNT2, was strikingly responsive to subtle changes in surface chemistry, exhibiting vastly different expression levels between adjacent regions. Our results suggest that the surface-bound gradient platform is well suited to screening surface chemistries for use in the field of stem cell technologies and regenerative medicine. PMID:24354633

Delalat, Bahman; Goreham, Renee V; Vasilev, Krasimir; Harding, Frances J; Voelcker, Nicolas H

2014-06-01

84

Detecting Problematic Observer Offsets in Sparse Photometry  

NASA Astrophysics Data System (ADS)

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.

Calderwood, T.

2014-06-01

85

Nanoscale Roughness and Morphology Affect the IsoElectric Point of Titania Surfaces  

PubMed Central

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 ? and the Debye length ?D. 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

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

2013-01-01

86

Affecting surface chirality via multicomponent adsorption of chiral and achiral molecules.  

PubMed

Here we report on the apparent reduction in surface chirality upon co-assembling a chiral and achiral molecule into a physisorbed self-assembled monolayer at the liquid/solid interface as revealed by scanning tunneling microscopy (STM). Chiral OPV with achiral thymine gives rise to surface-confined supramolecular diastereomers. PMID:25154626

Guo, Zongxia; De Cat, Inge; Van Averbeke, Bernard; Lin, Jianbin; Wang, Guojie; Xu, Hong; Lazzaroni, Roberto; Beljonne, David; Schenning, Albertus P H J; De Feyter, Steven

2014-09-11

87

Surface and Subsurface Geologic Risk Factors to Ground Water Affecting Brownfield Redevelopment Potential  

Microsoft Academic Search

brownfields. The model is derived from a space and time conceptual framework that identifies and measures the surface and subsurface risk the substances released on and just below the surface factors present at brownfield sites. The model then combines these by human activity and their interactions with the near- factors with a contamination extent multiplier at each site to create

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

2003-01-01

88

Some factors affecting EBSD pattern quality of Ga + ion-milled face centred cubic metal surfaces  

Microsoft Academic Search

Using a DualBeam™ platform, it is possible to generate crystallographic volumes of microstructure by sequentially milling submicron slices of a material using the focused ion beam (FIB) and mapping each newly created surface using electron backscatter diffraction (EBSD). The present work describes the influence of some FIB milling parameters on the quality of EBSD patterns obtained on ion-milled surfaces of

N. Mateescu; M. Ferry; W. Xu; J. M. Cairney

2007-01-01

89

From Spitzer Galaxy photometry to Tully-Fisher distances  

NASA Astrophysics Data System (ADS)

This paper involves a data release of the observational campaign: Cosmicflows with Spitzer (CFS). Surface photometry of the 1270 galaxies constituting the survey is presented. An additional ˜400 galaxies from various other Spitzer surveys are also analysed. CFS complements the Spitzer Survey of Stellar Structure in Galaxies, that provides photometry for an additional 2352 galaxies, by extending observations to low galactic latitudes (|b| < 30°). Among these galaxies are calibrators, selected in the K band, of the Tully-Fisher relation. The addition of new calibrators demonstrates the robustness of the previously released calibration. Our estimate of the Hubble constant using supernova host galaxies is unchanged, H0 = 75.2 ± 3.3 km s-1 Mpc-1. Distance-derived radial peculiar velocities, for the 1935 galaxies with all the available parameters, will be incorporated into a new data release of the Cosmicflows project. The size of the previous catalogue will be increased by 20 per cent, including spatial regions close to the Zone of Avoidance.

Sorce, J. G.; Tully, R. B.; Courtois, H. M.; Jarrett, T. H.; Neill, J. D.; Shaya, E. J.

2014-10-01

90

How surface roughness affects the angular dependence of the sputtering yield , A. Hassanein  

E-print Network

Brunauer­Emmett­Teller (BET) method and adsorption from hexane solution to measure the material sur- face area, where BET is a theory explains the physical adsorption of gas molecules on a material surface

Harilal, S. S.

91

Small Surface Pretilt Strikingly Affects the Director Profile during Poiseuille Flow of a Nematic Liquid Crystal  

NASA Astrophysics Data System (ADS)

Conventional nematic liquid crystal cells are fabricated with small surface pretilt of the director induced by rubbed polymer alignment. Depending on the orientation of the bounding surfaces, this may lead to two slightly different untwisted director configurations, splay and parallel. This small difference leads to remarkably different director profiles during pressure-driven flow, observed here using optical conoscopy. Data show excellent agreement with numerical modeling from Leslie-Ericksen-Parodi theory.

Holmes, C. J.; Cornford, S. L.; Sambles, J. R.

2010-06-01

92

Surface branch of the hydrologic cycle affecting Texas for water year 1959  

E-print Network

OF TABLES Number Page Estimated seasonal values of terrestial albedos for selected stations in Texas 29 Average monthly values of precipitation computed by various methods for Texas, water year 1959 38 Estimates of actual average monthly pre..., been defined and/or measured adequately. Some of these parameters are: a. temperature b. wind movement (at levels up to two meters from the surface) c. solar and terrestial radiation d. ground surface properties (type, albedo and moisture...

Gargiulo, Alphonse, Jr

2012-06-07

93

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

PubMed

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, ?. 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 ? 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 ? measurements. PMID:23957441

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

2013-10-01

94

Galileo Photometry of Asteroid 951 Gaspra  

USGS Publications Warehouse

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.

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

95

Lightcurve Photometry Opportunities: 2014 July-September  

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

96

Lightcurve Photometry Opportunities: 2014 April-June  

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

97

Lightcurve Photometry Opportunities: 2013 October-December  

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

98

Lightcurve Photometry Opportunities: 2014 October-December  

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

99

IC 4651 uvby photometry (Meibom, 2000)  

Microsoft Academic Search

New accurate CCD photometry in the u, v, b and y bands of the Stroemgren system filters has been obtained for 17640 stars to approximately. V=20mag in a approximately 21' x 21' field centered on the intermediate-age open cluster IC 4651. The observations was obtained with the Danish 1.5-m telescope at the European Southern Observatory, La Silla, Chile. Table 1

S. Meibom

2000-01-01

100

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

ERIC Educational Resources Information Center

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…

Buchanan, Michael T.; Hyde, Brendan

2008-01-01

101

Antecedent soil moisture affecting surface cracking of a Vertisol in field conditions  

Microsoft Academic Search

Cracking of shrink–swell soils influences landscape hydrology. Watershed models that address soil cracking phenomena generally use a relationship between shrinkage and current soil water content to estimate the extent of cracking. Although antecedent soil moisture prior to soil shrinkage is found to affect the shrinking of expansive soils in laboratory measurements, field observations are limited. In a previous study, a

Andrea Sz. Kishné; Cristine L. S. Morgan; Yufeng Ge; Wesley L. Miller

2010-01-01

102

Abiotic factors affecting the persistence of avian influenza virus in surface waters of waterfowl habitats.  

PubMed

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-?m 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

Keeler, Shamus P; Dalton, Melinda S; Cressler, Alan M; Berghaus, Roy D; Stallknecht, David E

2014-05-01

103

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

PubMed Central

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-?m 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

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

2014-01-01

104

Photometry with FORS at the ESO VLT  

E-print Network

ESO's two FOcal Reducer and low dispersion Spectrographs (FORS) are the primary imaging cameras for the VLT. Since they are not direct-imaging cameras, the accuracy of photometry which can routinely be obtained is limited by significant sky concentration and other effects. Photometric standard observations are routinely obtained by ESO, and nightly zero points are computed mainly for the purpose of monitoring the instrument performance. The accuracy of these zero points is about 10%. Recently, we have started a program to investigate, if and how percent-level absolute photometric accuracy with FORS can be achieved. The main results of this project are presented in this paper. We first discuss the quality of the flatfields and how it can be improved. We then use data with improved flat-fielding to investigate the usefulness of Stetson standard fields for FORS calibration and the accuracy which can be achieved. The main findings of the FORS Absolute Photometry Project program are as follows. There are significant differences between the sky flats and the true photometric response of the instrument which partially depend on the rotator angle. A second order correction to the sky flat significantly improves the relative photometry within the field. Percent level photometric accuracy can be achieved with FORS1. To achieve this accuracy, observers need to invest some of the assigned science time for imaging of photometric standard fields in addition to the routine nightly photometric calibration.

W. Freudling; M. Romaniello; F. Patat; P. Moller; E. Jehin; K. O'Brien

2006-10-24

105

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

106

Surface tension and contact angle of herbicide solutions affected by surfactants  

Microsoft Academic Search

Contact angle and surface tension were measured for distilled and hard water solutions of adjuvants, Ortho X-77, Span-20,\\u000a Sterox-NJ. Surfactant-WK, Triton B-1956, Triton X-114, Tween-20, and Sun Oil 11E. The same parameters were measured for suspensions\\u000a of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] and ametryne [2-(ethylamino)-4-(isopropylamino)-6-(methylthio)-s-triazine] with and without each adjuvant. All adjuvants reduced surface tension and contact angle of distilled water; Surfactant-WK\\u000a was

Megh Singh; J. R. Orsenigo; D. O. Shah

1984-01-01

107

How Do Silanes Affect the Lubricating Properties of Cationic Double Chain Surfactant on Silica Surfaces ?  

E-print Network

interaction between the silane and the surfactant, both able to adsorb on the glass surface. Investigations with glass after the silane hydrolysis 7,8 and with the matrix. A question then relates to the possible on friction properties of silica, glass or mica in presence of silane and surfactant mixture are not available

Paris-Sud XI, Université de

108

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

PubMed

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

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

2014-07-01

109

IL6 and IL8 levels after cardiopulmonary bypass are not affected by surface coating  

Microsoft Academic Search

Background. Contact of blood with the surfaces of the cardiopulmonary bypass (CPB) circuit has been implicated as a cause of the inflammatory response. We undertook a prospective randomized trial of 200 pediatric patients, all with a calculated total bypass flow of less than 2.3 L\\/min (< 0.96 L\\/m2\\/min).Methods. Patients were randomly assigned to 1 of 4 CPB groups: (1) Nonheparin-bonded

Stephen B Horton; Warwick W Butt; Richard J Mullaly; Clarke A Thuys; Eve B O’Connor; Keith Byron; Andrew D Cochrane; Christian P Brizard; Tom R Karl

1999-01-01

110

Superoxide Dismutase Activity in Pseudomonas putida Affects Utilization of Sugars and Growth on Root Surfaces  

Microsoft Academic Search

To investigate the role of superoxide dismutases (SOD) in root colonization and oxidative stress, mutants of Pseudomonas putida lacking manganese-superoxide dismutase (MnSOD) (sodA), iron-superoxide dismutase (FeSOD) (sodB), or both were generated. The sodA sodB mutant did not grow on components washed from bean root surfaces or glucose in minimal medium. The sodB and sodA sodB mutants were more sensitive than

YOUNG CHEOL KIM; CHARLES D. MILLER; ANNE J. ANDERSON

2000-01-01

111

Surface modification of poly( l -lactic acid) affects initial cell attachment, cell morphology, and cell growth  

Microsoft Academic Search

The object of this study was to develop a highly porous scaffold to be used in regeneration of blood vessels, nerves, and other hollow tissues with small openings. Using the phase-inversion method and a mixture of water and methanol as a coagulating agent, we prepared highly porous flat membranes from poly(l-lactic acid) (PLLA) with numerous pores both on the surface

Manae Yamaguchi; Toshio Shinbo; Toshiyuki Kanamori; Pi-chao Wang; Motohiro Niwa; Hiroyoshi Kawakami; Shoji Nagaoka; Kohichiro Hirakawa; Masahiro Kamiya

2004-01-01

112

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

PubMed Central

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

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

2012-01-01

113

Photometry Of The Semi-regular Variable Tx Tau  

Microsoft Academic Search

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

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

2009-01-01

114

Solid Surface Structure Affects Liquid Order at the Polystyrene/SAM Interface  

E-print Network

We present a combined x-ray and neutron reflectivity study characterizing the interface between polystyrene (PS) and silanized surfaces. Motivated by the large difference in slip velocity of PS on top of dodecyl-trichlorosilane (DTS) and octadecyl-trichlorosilane (OTS) found in previous studies, these two systems were chosen for the present investigation. The results reveal the molecular conformation of PS on silanized silicon. Differences in the molecular tilt of OTS and DTS are replicated by the adjacent phenyl rings of the PS. We discuss our findings in terms of a potential link between the microscopic interfacial structure and dynamic properties of polymeric liquids at interfaces.

Philipp Gutfreund; Oliver Bäumchen; Dorothee van der Grinten; Renate Fetzer; Marco Maccarini; Karin Jacobs; Hartmut Zabel; Max Wolff

2011-04-05

115

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

USGS Publications Warehouse

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.

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

2010-01-01

116

Distortion of trichome morphology by the hairless mutation of tomato affects leaf surface chemistry.  

PubMed

Trichomes are specialized epidermal structures that function as physical and chemical deterrents against arthropod herbivores. Aerial tissues of cultivated tomato (Solanum lycopersicum) are populated by several morphologically distinct trichome types, the most abundant of which is the type VI glandular trichome that produces various specialized metabolites. Here, the effect of the hairless (hl) mutation on trichome density and morphology, chemical composition, and resistance to a natural insect herbivore of tomato was investigated. The results show that the major effect of hl on pubescence results from structural distortion (bending and swelling) of all trichome types in aerial tissues. Leaf surface extracts and isolated type VI glands from hl plants contained wild-type levels of monoterpenes, glycoalkaloids, and acyl sugars, but were deficient in sesquiterpene and polyphenolic compounds implicated in anti-insect defence. No-choice bioassays showed that hl plants are compromised in resistance to the specialist herbivore Manduca sexta. These results establish a link between the morphology and chemical composition of glandular trichomes in cultivated tomato, and show that hl-mediated changes in these leaf surface traits correlate with decreased resistance to insect herbivory. PMID:20018901

Kang, Jin-Ho; Shi, Feng; Jones, A Daniel; Marks, M David; Howe, Gregg A

2010-02-01

117

Nephrocalcin isoforms coat crystal surfaces and differentially affect calcium oxalate monohydrate crystal morphology, growth, and aggregation  

NASA Astrophysics Data System (ADS)

Calcium oxalate crystals were grown in the presence of each of the four isoforms of nephrocalcin (NC), a urinary protein proposed to inhibit kidney stone growth. Crystal size, morphology, and surface topography were assessed using optical microscopy, Coulter counter measurements, scanning electron microscopy (SEM), and atomic force microscopy (AFM). All crystals grown in the presence of NC isoforms were calcium oxalate monohydrates (COMs). Crystals formed in the presence of NC-A were smaller than control crystals, which were grown without NC, according to optical and SEM results, suggesting that NC-A restricts crystal growth. In contrast, samples grown with NC-C and NC-D exhibit more large crystals and several crystal aggregates, suggesting that NC-C and -D promote crystal growth and aggregation. Crystals grown with NC-B are not significantly larger or smaller than controls. AFM images of the crystals reveal significantly different surface textures on the control crystals relative to those grown with NC isoforms, indicating that NC acts by coating nascent calcium oxalate crystals. These are the first reported AFM images that show topography of NC-coated crystals. These findings suggest that NC isoforms have distinct interactions with different COM crystal faces, which may be responsible for their different effects on crystal growth and morphology.

Kurutz, Josh W.; Carvalho, Mauricio; Nakagawa, Yasushi

2003-08-01

118

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

PubMed

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. PMID:20727017

Leake, Stanley A; Reeves, Howard W; Dickinson, Jesse E

2010-01-01

119

Superfast Photometry with the MANIA Complex  

NASA Astrophysics Data System (ADS)

We describe the hard/software MANIA complex for carrying out superfast photometry. A new type of time-code converter Quantochron allows us to measure arrival times of photons registered by a photodetector with time resolution up to 20 ns in 216 channels (space, colours, polarization, etc.) simultaneously. Special software was developed to investigate variability on a time-scale of 2 × 10-8-103 s by statistical analysis of the time inverval distribution between detected photons and classical light curves. The results of some observations are presented.

Shvartsman, V. F.; Bernstein, I. N.; Beskin, G. M.; Komarova, V. N.; Neizvestny, S. I.; Plokhotnichenko, V. L.; Popova, M. Yu.; Zhuravkov, A. V.

120

Simultaneous Filter Photometry of V1727 Cygni  

NASA Astrophysics Data System (ADS)

We present high speed optical photometry of the low mass X-ray binary V1727 Cygni. Simultaneous observations were obtained during five consecutive nights in 2013 using McDonald Observatory's 2.7-m and 2.1-m telescopes using u' and R filters respectively. There is very little variation in the u' intensity. The R data displays night to night and orbital period variations. We discuss constraints on system properties provided by these multi-filter data. This program is funded by NSF grant 0958783.

Sundin, Emma; Mason, P. A.; Robinson, E. L.; Morales, J.; Gomez, S.; Gonzalez, R.; Lopez, I.; Bell, K.

2014-01-01

121

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

PubMed

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

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

2014-11-01

122

Superoxide Dismutase Activity in Pseudomonas putida Affects Utilization of Sugars and Growth on Root Surfaces  

PubMed Central

To investigate the role of superoxide dismutases (SOD) in root colonization and oxidative stress, mutants of Pseudomonas putida lacking manganese-superoxide dismutase (MnSOD) (sodA), iron-superoxide dismutase (FeSOD) (sodB), or both were generated. The sodA sodB mutant did not grow on components washed from bean root surfaces or glucose in minimal medium. The sodB and sodA sodB mutants were more sensitive than wild type to oxidative stress generated within the cell by paraquat treatment. In single inoculation of SOD mutants on bean, only the sodA sodB double mutant was impaired in growth on root surfaces. In mixed inoculations with wild type, populations of the sodA mutant were equal to those of the wild type, but levels of the sodB mutant and, to a great extent, the sodA sodB mutant, were reduced. Confocal microscopy of young bean roots inoculated with green fluorescent protein-tagged cells showed that wild type and SOD single mutants colonized well predominantly at the root tip but that the sodA sodB double mutant grew poorly at the tip. Our results indicate that FeSOD in P. putida is more important than MnSOD in aerobic metabolism and oxidative stress. Inhibition of key metabolic enzymes by increased levels of superoxide anion may cause the impaired growth of SOD mutants in vitro and in planta. PMID:10742227

Kim, Young Cheol; Miller, Charles D.; Anderson, Anne J.

2000-01-01

123

Water color affects the stratification, surface temperature, heat content, and mean epilimnetic irradiance of small lakes  

USGS Publications Warehouse

The effects of water color on lake stratification, mean epilimnetic irradiance, and lake temperature dynamics were examined in small, north-temperate lakes that differed widely in water color (1.5-19.8 m -1). Among these lakes, colored lakes differed from clear lakes in the following ways: (i) the epilimnia were shallower and colder, and mean epilimnetic irradiance was reduced; (ii) the diel temperature cycles were more pronounced; (iii) whole-lake heat accumulation during stratification was reduced. The depth of the epilimnion ranged from 2.5 m in the clearest lake to 0.75 m in the most colored lake, and 91% of the variation in epilimnetic depth was explained by water color. Summer mean morning epilimnetic temperature was ???2??C cooler in the most colored lake compared with the clearest lake. In clear lakes, the diel temperature range (1.4 ?? 0.7??C) was significantly (p = 0.01) less than that in the most colored lake (2.1 ?? 1.0??C). Change in whole-lake heat content was negatively correlated with water color. Increasing water color decreased light penetration more than thermocline depth, leading to reduced mean epilimnetic irradiance in the colored lakes. Thus, in these small lakes, water color significantly affected temperature, thermocline depth, and light climate. ?? 2006 NRC.

Houser, J. N.

2006-01-01

124

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

PubMed

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

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

2013-01-01

125

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

126

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

SciTech Connect

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.

Hale, L C; Taylor, J S

2008-04-03

127

Globular Cluster Ages and Stromgren CCD Photometry  

E-print Network

Stromgren uvby CCD photometry can be used in a variety of ways to constrain the absolute and relative ages of globular clusters. The reddening corrected (v-y, c1) diagram offers the means to derive ages that are completely independent of distance. Very precise differential ages for clusters of the same chemical composition may also be determined from such 2-color plots, or from measurements of the magnitude difference, Delta_u, between the subgiant and horizontal branches on the $u-y, u$ plane (where both of these features are flat and well-defined, even for clusters like M13 that have extremely blue HBs on the (B-V, V) diagram). Based on high-quality photometry we find that: (1) M92 is 15 Gyr old, (2) M3 and M13 differ in age by < 1 Gyr, and (3) NGC 288, NGC 362, and NGC 1851 are coeval to within ~1.5 Gyr. These results strongly suggest that age cannot be the only ``second parameter''. Finally, we suggest that the observed variations in c1 among giant branch stars in all the metal-poor clusters that we have studied so far are likely due to star-to-star C and N abundance variations, and potentially indicate that most (if not all) globular clusters have ``primordial'' variations in at least these elements.

Frank Grundahl

1999-09-23

128

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

PubMed Central

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 (?=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.

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

129

Enteric YaiW Is a Surface-Exposed Outer Membrane Lipoprotein That Affects Sensitivity to an Antimicrobial Peptide  

PubMed Central

yaiW is a previously uncharacterized gene found in enteric bacteria that is of particular interest because it is located adjacent to the sbmA gene, whose bacA ortholog is required for Sinorhizobium meliloti symbiosis and Brucella abortus pathogenesis. We show that yaiW is cotranscribed with sbmA in Escherichia coli and Salmonella enterica serovar Typhi and Typhimurium strains. We present evidence that the YaiW is a palmitate-modified surface exposed outer membrane lipoprotein. Since BacA function affects the very-long-chain fatty acid (VLCFA) modification of S. meliloti and B. abortus lipid A, we tested whether SbmA function might affect either the fatty acid modification of the YaiW lipoprotein or the fatty acid modification of enteric lipid A but found that it did not. Interestingly, we did observe that E. coli SbmA suppresses deficiencies in the VLCFA modification of the lipopolysaccharide of an S. meliloti bacA mutant despite the absence of VLCFA in E. coli. Finally, we found that both YaiW and SbmA positively affect the uptake of proline-rich Bac7 peptides, suggesting a possible connection between their cellular functions. PMID:24214946

Arnold, Markus F. F.; Caro-Hernandez, Paola; Tan, Karen; Runti, Giulia; Wehmeier, Silvia; Scocchi, Marco; Doerrler, William T.; Ferguson, Gail P.

2014-01-01

130

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

PubMed

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. Mg(2+) has been reported to affect TSase activity, but the mechanism of this interaction has not been investigated. Here we show that Mg(2+) 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 Mg(2+) near the glutamyl moiety of the folate cofactor, providing the first structural evidence for Mg(2+) binding to TSase. The kinetics and NMR relaxation experiments suggest that the weak binding of Mg(2+) to the protein surface stabilizes the closed conformation of the ternary enzyme complex and reduces the entropy of activation on the hydride transfer step. Mg(2+) accelerates the hydride transfer by ~7-fold but does not affect the magnitude or temperature dependence of the intrinsic kinetic isotope effect. These results suggest that Mg(2+) 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 Mg(2+) concentration can modulate enzyme activity through long-range interactions in the protein, rather than binding at the active site. The interaction of Mg(2+) with the glutamyl tail of the folate cofactor and nonconserved residues of bacterial TSase may assist in designing antifolates with polyglutamyl substitutes as species-specific antibiotic drugs. PMID:23611499

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

2013-05-22

131

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

PubMed Central

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

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

2013-01-01

132

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

133

Coating thickness affects surface stress measurement of brush electro-plating nickel coating using Rayleigh wave approach.  

PubMed

A surface ultrasonic wave approach was presented for measuring surface stress of brush electro-plating nickel coating specimen, and the influence of coating thickness on surface stress measurement was discussed. In this research, two Rayleigh wave transducers with 5MHz frequency were employed to collect Rayleigh wave signals of coating specimen with different static tensile stresses and different coating thickness. The difference in time of flight between two Rayleigh wave signals was determined based on normalized cross correlation function. The influence of stress on propagation velocity of Rayleigh wave and the relationship between the difference in time of flight and tensile stress that corresponded to different coating thickness were discussed. Results indicate that inhomogeneous deformation of coating affects the relationship between the difference in time of flight and tensile stress, velocity of Rayleigh wave propagating in coating specimen increases with coating thickness increasing, and the variation rate reduces of difference in time of flight with tensile stress increasing as coating thickness increases. PMID:22534060

Liu, Bin; Dong, Shiyun; Xu, Binshi; He, Peng

2012-09-01

134

Ten Recent Enhancements To Aperture Photometry Tool  

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

135

TERMS PHOTOMETRY OF KNOWN TRANSITING EXOPLANETS  

SciTech Connect

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.

Dragomir, Diana; Kane, Stephen R.; Ciardi, David R.; Gelino, Dawn M.; Payne, Alan; Ramirez, Solange V.; Von Braun, Kaspar; Wyatt, Pamela [NASA Exoplanet Science Institute, Caltech, MS 100-22, Pasadena, CA 91125 (United States); Pilyavsky, Genady; Mahadevan, Suvrath; Wright, Jason T. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Zachary Gazak, J. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Rabus, Markus, E-mail: diana@phas.ubc.ca [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)

2011-10-15

136

How do Atmospheres Affect Planetary Temperatures? Activity C Can we Model an Atmosphere's Effect Upon a Planet's Surface Temperature?  

NSDL National Science Digital Library

In this activity, students simulate the interaction of variables, including carbon dioxide, in a radiation balance exercise using a spreadsheet-based radiation balance model. Through a series of experiments, students attempt to mimic the surface temperatures of Earth, Mercury, Venus and Mars, and account for the influence of greenhouse gases in atmospheric temperatures. The activity supports inquiry into the real-world problem of contemporary climate change. Student-collected data is needed from activity A in the same module, "How do atmospheres interact with solar energy?" to complete this activity. Included in the resource are several student data sheets and a teacher's guide. This activity is part of module 4, "How do Atmospheres Affect Planetary Temperatures?" in Earth Climate Course: What Determines a Planet's Climate? The course aims to help students to develop an understanding of our environment as a system of human and natural processes that result in changes that occur over various space and time scales.

137

Surface charges of the membrane crucially affect regulation of Na,K-ATPase by phospholemman (FXYD1).  

PubMed

The human ?1/His10-?1 isoform of Na,K-ATPase has been reconstituted as a complex with and without FXYD1 into proteoliposomes of various lipid compositions in order to study the effect of the regulatory subunit on the half-saturating Na? concentration (K(½)) of Na? ions for activation of the ion pump. It has been shown that the fraction of negatively charged lipid in the bilayer crucially affects the regulatory properties. At low concentrations of the negatively charged lipid DOPS (<10 %), FXYD1 increases K(½) of Na? ions for activation of the ion pump. Phosphorylation of FXYD1 by protein kinase A at Ser68 abrogates this effect. Conversely, for proteoliposomes made with high concentrations of DOPS (>10 %), little or no effect of FXYD1 on the K(½) of Na? ions is observed. Depending on ionic strength and lipid composition of the proteoliposomes, FXYD1 can alter the K(½) of Na? ions by up to twofold. We propose possible molecular mechanisms to explain the regulatory effects of FXYD1 and the influence of charged lipid and protein phosphorylation. In particular, the positively charged C-terminal helix of FXYD1 appears to be highly mobile and may interact with the cytoplasmic N domain of the ?-subunit, the interaction being strongly affected by phosphorylation at Ser68 and the surface charge of the membrane. PMID:24105627

Cirri, Erica; Kirchner, Corinna; Becker, Simon; Katz, Adriana; Karlish, Steven J; Apell, Hans-Jürgen

2013-12-01

138

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

PubMed Central

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

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

139

The post-translational modification of the Clostridium difficile flagellin affects motility, cell surface properties and virulence.  

PubMed

Clostridium difficile is a prominent nosocomial pathogen, proliferating and causing enteric disease in individuals with a compromised gut microflora. We characterized the post-translational modification of flagellin in C. difficile 630. The structure of the modification was solved by nuclear magnetic resonance and shown to contain an N-acetylglucosamine substituted with a phosphorylated N-methyl-l-threonine. A reverse genetics approach investigated the function of the putative four-gene modification locus. All mutants were found to have truncated glycan structures by LC-MS/MS, taking into account bioinformatic analysis, we propose that the open reading frame CD0241 encodes a kinase involved in the transfer of the phosphate to the threonine, the CD0242 protein catalyses the addition of the phosphothreonine to the N-acetylglucosamine moiety and CD0243 transfers the methyl group to the threonine. Some mutations affected motility and caused cells to aggregate to each other and abiotic surfaces. Altering the structure of the flagellin modification impacted on colonization and disease recurrence in a murine model of infection, showing that alterations in the surface architecture of C. difficile vegetative cells can play a significant role in disease. We show that motility is not a requirement for colonization, but that colonization was compromised when the glycan structure was incomplete. PMID:25135277

Faulds-Pain, Alexandra; Twine, Susan M; Vinogradov, Evgeny; Strong, Philippa C R; Dell, Anne; Buckley, Anthony M; Douce, Gillian R; Valiente, Esmeralda; Logan, Susan M; Wren, Brendan W

2014-10-01

140

Disk-resolved photometry of Asteroid (2867) Steins  

NASA Astrophysics Data System (ADS)

We present a new method to perform disk-resolved photometry in order to investigate the intrinsic photometric properties of the surface of small Solar System bodies. We adopt the standard approach where a shape model is combined with a photometric formalism - in practise the Hapke formalism - to remove the effects of topography and recover the photometric (Hapke) parameters of either the global surface or, in its most elaborated form, the spatial variations of these parameters across the surface. Our method operates in the space of the facets representing the three-dimensional shape of the body, whereas all past analysis have always been performed in the space of the image pixels although they are not intrinsic to the surface of the body. This has the advantage of automatically tracking the same local surface element on a series of images. We first apply our method to images of the nucleus of Comet 9P/Tempel 1 obtained by the High-Resolution Imager (HRI) instrument on board the Deep Impact spacecraft and our derived Hapke parameters are in good agreement with those published by Li et al. (Li, J.-Y. et al. [2007]. Icarus 187, 41-55) within their respective uncertainties. We confirm the presence of an extended region of higher roughness in the southern hemisphere of the nucleus and the higher albedo of the ice-rich regions identified by Sunshine et al. (Sunshine, J.M. et al. [2006]. Science 311, 1453-1455) near the equator. The photometric properties of Asteroid (2867) Steins are then studied from multi-spectral images obtained with the OSIRIS Wide Angle Camera (WAC) on board the Rosetta spacecraft during its flyby on 5 September 2008. Our analysis indicates that the surface is highly porous (?84%) and that it exhibits both a shadow-hiding opposition effect (SHOE) and probably, a coherent-backscatter opposition effect (CBOE). The single scattering albedo is the highest (SSA = 0.57) ever observed among small bodies visited by spacecrafts. Our modelled roughness parameter is indicative of a high microscale roughness. The surface of Steins may in fact exhibit a fractal surface with high roughness present on a large range of scales, from micrometers to centimeters. The geometric and Bond albedos are calculated with the Hapke parameters yielding Ap = 0.39 ± 0.02 and AB = 0.24 ± 0.01. This high albedo is consistent with an iron-poor surface composition similar to aubrite meteorites which are suspected to originate from the E-type asteroids. We find no photometric variations on the surface at the (limited) spatial resolution of the WAC images.

Spjuth, S.; Jorda, L.; Lamy, P. L.; Keller, H. U.; Li, J.-Y.

2012-11-01

141

The TAOS Project: High-Speed Crowded Field Aperture Photometry  

NASA Astrophysics Data System (ADS)

We have devised an aperture photometry pipeline for data reduction of image data from the Taiwanese-American Occultation Survey (TAOS). The photometry pipeline has high computational performance, and is capable of real-time photometric reduction of images containing up to 1000 stars, within the sampling rate of 5 Hz. The pipeline is optimized for both speed and signal-to-noise performance, and in the latter category it performs nearly as well as DAOPHOT. This paper provides a detailed description of the TAOS aperture photometry pipeline.

Zhang, Z.-W.; Kim, D.-W.; Wang, J.-H.; Lehner, M. J.; Chen, W. P.; Byun, Y.-I.; Alcock, C.; Axelrod, T.; Bianco, F. B.; Coehlo, N. K.; Cook, K. H.; Dave, R.; de Pater, I.; Giammarco, J.; King, S.-K.; Lee, T.; Lin, H.-C.; Marshall, S. L.; Porrata, R.; Protopapas, P.; Rice, J. A.; Schwamb, M. E.; Wang, S.-Y.; Wen, C.-Y.

2009-12-01

142

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

NASA Astrophysics Data System (ADS)

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.

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

2007-12-01

143

The surface photometry catalogue of the ESO-Uppsala galaxies  

Microsoft Academic Search

Not Available Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use: Authors Title Keywords (in text query field) Return: Query Results Return items starting with number Query Form Database: Astronomy Physics arXiv e-prints

Andris Lauberts; Edwin A. Valentijn

1989-01-01

144

Detection of Extrasolar Planets by Transit Photometry  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

145

A catalogue of IJK photometry of Planetary Nebulae with DENIS  

E-print Network

Near-infrared photometry of planetary nebulae (PNe) allows the classification of those objects. We present the largest homogeneous sample so far, obtained with the Deep Near Infrared Southern Sky Survey (DENIS).

S. Schmeja; S. Kimeswenger

2001-05-15

146

Induction effects for heterochromatic brightness matching, heterochromatic flicker photometry,  

E-print Network

Induction effects for heterochromatic brightness matching, heterochromatic flicker photometry, and minimally distinct border: implications for the neural mechanisms underlying induction Karen L. Gunther manuscript received April 21, 2005; accepted April 24, 2005 Brightness induction refers to the finding

Dobkins, Karen R.

147

BINARY STAR SYNTHETIC PHOTOMETRY AND DISTANCE DETERMINATION USING BINSYN  

SciTech Connect

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.

Linnell, Albert P. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); DeStefano, Paul [8508B Midvale Ave. North, Seattle, WA 98103 (United States); Hubeny, Ivan, E-mail: linnell@astro.washington.edu, E-mail: pdestefa@uw.edu, E-mail: hubeny@as.arizona.edu [Steward Observatory and Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States)

2013-09-15

148

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

NASA Astrophysics Data System (ADS)

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 ?2 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 E^{poles}_{B-V} = 0.036 ± 0.002 at the Galactic poles, is a suitable approximation of the actual reddening encountered at Galactic latitudes |b| >= 25°.

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

149

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

NASA Astrophysics Data System (ADS)

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.

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

150

NEW UBVRI PHOTOMETRY OF 234 M33 STAR CLUSTERS  

SciTech Connect

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.

Ma Jun, E-mail: majun@nao.cas.cn [National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100012 (China); Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

2013-04-15

151

Microlensing for extrasolar planets : improving the photometry  

NASA Astrophysics Data System (ADS)

Gravitational Microlensing, as a technique for detecting Extrasolar Planets, is recognised for its potential in discovering small-mass planets similar to Earth, at a distance of a few Astronomical Units from their host stars. However, analysing the data from microlensing events (which statistically rarely reveal planets) is complex and requires continued and intensive use of various networks of telescopes working together in order to observe the phenomenon. As such the techniques are constantly being developed and refined; this project outlines some steps of the careful analysis required to model an event and ensure the best quality data is used in the fitting. A quantitative investigation into increasing the quality of the original photometric data available from any microlensing event demonstrates that 'lucky imaging' can lead to a marked improvement in the signal to noise ratio of images over standard imaging techniques, which could result in more accurate models and thus the calculation of more accurate planetary parameters. In addition, a simulation illustrating the effects of atmospheric turbulence on exposures was created, and expanded upon to give an approximation of the lucky imaging technique. This further demonstrated the advantages of lucky images which are shown to potentially approach the quality of those expected from diffraction limited photometry. The simulation may be further developed for potential future use as a 'theoretical lucky imager' in our research group, capable of producing and analysing synthetic exposures through customisable conditions.

Bajek, David J.

152

BVI CCD photometry of 47 Tucanae  

SciTech Connect

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.

Alcaino, G.; Liller, W.

1987-08-01

153

Recent Advances in Video Meteor Photometry  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

154

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

PubMed Central

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 ?E 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

Tuncer, Duygu; Karaman, Emel; Firat, Esra

2013-01-01

155

The RSA survey of dwarf galaxies, 1: Optical photometry  

NASA Technical Reports Server (NTRS)

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.

Vader, J. Patricia; Chaboyer, Brian

1994-01-01

156

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

NASA Astrophysics Data System (ADS)

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.

Knight, Matthew M.; Schleicher, David G.

2013-02-01

157

Mesopic luminance assessed with minimum motion photometry.  

PubMed

We measured the relative contribution of rods and cones to luminance across a range of photopic, mesopic, and scotopic adaptation levels and at various retinal eccentricities. We isolated the luminance channel by setting motion-based luminance nulls (minimum motion photometry) using annular stimuli. Luminance nulls between differently colored stimuli require equality in a weighted sum of rod and cone excitations. The relative cone weight increases smoothly from the scotopic range, where rods dominate, to photopic levels, where rod influence becomes negligible. The change from rod to cone vision does not occur uniformly over the visual field. The more peripheral the stimulus location, the higher is the light level required for cones to participate strongly. The relative cone contribution can be described by a sigmoid function of intensity, with two parameters that each depend on the eccentricity and spatial frequency of the stimulus. One parameter determines the "meso-mesopic" luminance--the center of the mesopic range, at which rod and cone contributions are balanced. This increases with eccentricity, reflecting an increase in the meso-mesopic luminance from 0.04 scotopic cd/m(2) at 2° eccentricity to 0.44 scotopic cd/m(2) at 18°. The second parameter represents the slope of the log-log threshold-versus-intensity curve (TVI curve) for rod vision. This parameter inversely scales the width of the mesopic range and increases only slightly with eccentricity (from 0.73 at 2° to 0.78 for vision at 18° off-axis). PMID:21868482

Raphael, Sabine; MacLeod, Donald I A

2011-01-01

158

HST BVI photometry of Triton and Proteus  

NASA Astrophysics Data System (ADS)

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.

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

2006-12-01

159

VizieR Online Data Catalog: Galaxies morphology and IR photometry III. (Gavazzi+, 2000)  

NASA Astrophysics Data System (ADS)

We present near-infrared H-band (1.65?m) surface photometry of 558 galaxies in the Coma Supercluster and in the Virgo cluster. This data set, obtained with the Arcetri NICMOS3 camera ARNICA mounted on the Gornergrat Infrared Telescope, is aimed at complementing, with observations of mostly early-type objects, our NIR survey of spiral galaxies in these regions, presented in previous papers of this series. Magnitudes at the optical radius, total magnitudes, isophotal radii and light concentration indices are derived. We confirm the existence of a positive correlation between the near-infrared concentration index and the galaxy H-band luminosity (2 data files).

Gavazzi, G.; Franzetti, P.; Scodeggio, M.; Boselli, A.; Pierini, D.; Baffa, C.; Lisi, F.; Hunt, L. K.

1999-11-01

160

Stellar Magnetism in the Era of Space-Based Precision Photometry  

NASA Astrophysics Data System (ADS)

The advent of precision space-based photometric missions such as MOST, CoRoT and Kepler has revealed stellar magnetic activity in unprecedented detail. These observations enable new investigations into the fundamental nature of stellar magnetism by furthering our understanding of the stellar rotation and differential rotation that generate the field, and the photometric variability caused by the surface manifestations of the field. In the case of stars with planetary candidates, these data also offer synergy between studies of stars and planets. Here, I review the possibilities and challenges for deepening our understanding of magnetism in solar-like stars in the era of space-based precision photometry.

Walkowicz, Lucianne M.

2014-08-01

161

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...

162

First time-series optical photometry from Antarctica  

E-print Network

Beating the Earth's day-night cycle is mandatory for long and continuous time-series photometry and had been achieved with either large ground-based networks of observatories at different geographic longitudes or when conducted from space. A third possibility is offered by a polar location with astronomically-qualified site characteristics. Aims. In this paper, we present the first scientific stellar time-series optical photometry from Dome C in Antarctica and analyze approximately 13,000 CCD frames taken in July 2007. We conclude that high-precision CCD photometry with exceptional time coverage and cadence can be obtained at Dome C in Antarctica and be successfully used for time-series astrophysics.

K. G. Strassmeier; R. Briguglio; T. Granzer; G. Tosti; I. DiVarano; I. Savanov; M. Bagaglia; S. Castellini; A. Mancini; G. Nucciarelli; O. Straniero; E. Distefano; S. Messina; G. Cutispoto

2008-07-18

163

CCD photometry of bright stars using objective wire mesh  

E-print Network

Obtaining accurate photometry of bright stars from the ground remains tricky because of the danger of overexposure of the target and/or lack of suitable nearby comparison star. The century-old method of the objective wire mesh used to produce multiple stellar images seems attractive for precision CCD photometry of such stars. Our tests on beta Cep and its comparison star differing by 5 magnitudes prove very encouraging. Using a CCD camera and a 20 cm telescope with objective covered with a plastic wire mesh, located in poor weather conditions we obtained differential photometry of precision 4.5 mmag per 2 min exposure. Our technique is flexible and may be tuned to cover as big magnitude range as 6 - 8 magnitudes. We discuss the possibility of installing a wire mesh directly in the filter wheel.

Kami?ski, Krzysztof; Zgórz, Marika

2014-01-01

164

UBV(RI)c photometry of Stock 16 (Vazquez+, 2005)  

NASA Astrophysics Data System (ADS)

CCD UBV(RI)c imaging photometry was carried out in the field of Stock 16 along two observational runs at the University of Toronto Southern Observatory, Las Campanas, Chile, using the Hellen Sawyer Hogg 60-cm telescope: on the nights of 1994 April 13, 14 and 16, we obtained UBVRI photometry for four frames with the nitrogen-cooled detector PM METHACROME UV coated (0.45"/pix) covering 4' on a side; three more frames were exposed on the nights of 1996 February 25 and 26 in the UBV(I)c bands (this time, the detector was glycol-refrigerated). (1 data file).

Vazquez, R. A.; Baume, G. L.; Feinstein, C.; Nunez, J. A.; Vergne, M. M.

2005-02-01

165

Characterization of transiting exoplanets by way of differential photometry  

NASA Astrophysics Data System (ADS)

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 habitability. The activity has been designed for a high-school or undergraduate university level and introduces fundamental concepts in astrophysics and an understanding of the basis for exoplanetary science, the transit method and digital photometry.

Cowley, Michael; Hughes, Stephen

2014-05-01

166

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

NASA Astrophysics Data System (ADS)

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 ? values. Studies of the effect of roughness and surface flaws on wettability revealed that the cos ? 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.

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

2012-12-01

167

Iontophoresis and Flame Photometry: A Hybrid Interdisciplinary Experiment  

ERIC Educational Resources Information Center

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…

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

2010-01-01

168

NIR photometry of MASTER OTJ013135.43+555831.5  

NASA Astrophysics Data System (ADS)

Following the report on MASTER OTJ013135.43+555831.5 by Denisenko et al.,2014 (Atel #6432). We carried out NIR photometry recently, On October 4th,2014 (JD2456934.8775), we found the object with fluxes corresponding to J = 14.879 +/- 0.05, H = 13.431 +/- 0,05 and Ks = 12.236 +/- 0.05.

Carrasco, L.; Porras, A.; Recillas, E.; Leon-Tavares, J.; Chavushyan, V.; Carraminana, A.

2014-10-01

169

Characterization of Transiting Exoplanets by Way of Differential Photometry  

ERIC Educational Resources Information Center

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…

Cowley, Michael; Hughes, Stephen

2014-01-01

170

Far-ultraviolet stellar photometry: A field in Orion  

Microsoft Academic Search

Far-ultraviolet photometry for 625 objects in Orion is presented. These data were extracted from electrographic camera images obtained during sounding rocket flights in 1975 and 1982. The 1975 images were centered close to the belt of Orion while the 1982 images were centered approximately 9 deg further north. One hundred and fifty stars fell in the overlapping region and were

Edward G. Schmidt; George R. Carruthers

1993-01-01

171

Photometry of the Under Observed RR Lyrae Star GM Orionis  

NASA Astrophysics Data System (ADS)

We report photometric observations of the under-observed RR Lyrae variable star GM Orionis. Earlier observations show an inconsistency in the star’s observed brightness, while the amplitude of variability has remained constant. We show photometry that has been collected over a three-year period demonstrating a continued increase in brightness. We discuss possible explanations.

Brown, Justin; Boyle, R. J.

2014-01-01

172

Multicolor CCD Photometry of the Open Cluster IC 361  

Microsoft Academic Search

CCD photometry in the eight-color Vilnius + I system for 7250 stars down to I = 19.6 mag has been obtained in the 20 arcmin × 26' field of the open cluster IC 361 in Camelopardalis. The catalog of 1420 stars down to V ˜ 18.5 mag is presented. It contains the coordinates, V magnitudes, seven color indices, quantitative photometric

J. Zdanavicius; S. Bartasiute; R. P. Boyle; F. J. Vrba; K. Zdanavicius

2010-01-01

173

BVRI CCD Photometry of the Open Cluster IC 4996  

Microsoft Academic Search

CCD observations in the BVRI system of 126 stars in the central part of the open cluster IC 4996 are presented. The precision of the photometry and the parameters of the cluster are discussed. A distance of r = 1620 pc and an age t = 9 Myr of the cluster are determined.

V. Vansevicius; A. Bridzius; A. Pucinskas; T. Sasaki Sasaki

1996-01-01

174

A Laboratory of Photometry and Radiometry of Light Pollution (LPLAB)  

Microsoft Academic Search

We present the Laboratory of Photometry and Radiometry of Light Pollution (LPLAB) that we set up to provide the Light Pollution Science and Technology Institute (ISTIL) of instruments and calibration services to support its scientific and technological research on light pollution and related environmental effects. The laboratory equipments are characterized by low light intensity measurement and calibration capabilities and by

P. Cinzano

2003-01-01

175

CCD Photometry of Nova V1500 Cygni Twenty Years After  

E-print Network

We report on CCD photometry of Nova V1500 Cygni obtained in July 1995 to show that twenty years after outburst, being of about 18~mag, the star can still be observed with small telescopes. The 0.1396 day period continues to be stable.

I. Semeniuk; A. Olech; M. Nalezyty

1995-12-14

176

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 ...

177

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

Microsoft Academic Search

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

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

2010-01-01

178

Penetrating the Surface: The Impact of Visual Format on Readers’ Affective Responses to Authentic Foreign Language Texts  

Microsoft Academic Search

This paper examines visual and affective factors involved in the reading of foreign language texts. It draws on the results of a pilot study among students of post-compulsory school stage studying French in England. Through a detailed analysis of students’ reactions to texts, it demonstrates that the use of ‘authentic’ documents under currently held notions of ‘authenticity’ may have a

Ian Maun

2006-01-01

179

Characterizing Young Brown Dwarfs Using Synthetic Photometry and Expanded Spectral Energy Distributions  

NASA Astrophysics Data System (ADS)

Brown dwarfs cool, shrink and fade with time; therefore, older and more massive objects can have the same optical spectral types as younger, less massive brown dwarfs. Ambiguity in their near-infrared spectra further obfuscates crucial physical parameters such as effective temperature, surface gravity, metallicity, and dust and clouds. We attempt to disentangle these parameters by calculating a suite of synthetic colors from PHOENIX model atmospheres, using confirmed young brown dwarfs as benchmark objects to identify colors sensitive to surface gravity. We also construct nearly complete spectral energy distributions (SEDs) by combining WISE mid-infrared photometry with our extensive database of optical and near-infrared spectra and parallaxes. With the extended SEDs of known young objects and increased wavelength baseline of diagnostic colors we will be able to identify new young candidates to expand our sample of young brown dwarfs and understand their atmospheric properties.

Filippazzo, Joe; Rice, E. L.; Cruz, K. L.; Faherty, J.; BDNYC

2013-01-01

180

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

PubMed Central

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

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

2014-01-01

181

Apatite formation on bioactive calcium-silicate cements for dentistry affects surface topography and human marrow stromal cells proliferation  

Microsoft Academic Search

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

Maria Giovanna Gandolfi; Gabriela Ciapetti; Paola Taddei; Francesca Perut; Anna Tinti; Marcio Vivan Cardoso; Bart Van Meerbeek; Carlo Prati

2010-01-01

182

Surfaces  

E-print Network

Surfaces is a collection of four individual essays which focus on the characteristics and tactile qualities of surfaces within a variety of perceived landscapes. Each essay concentrates on a unique surface theme and purpose; ...

DeMaio, Ernest Vincent, 1964-

1989-01-01

183

CCD photometry of the Uranian satellites  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

184

Galileo Photometry of Asteroid 243 Ida  

Microsoft Academic Search

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 albedop= 0.21±0.030.01and Bond albedoAB= 0.081±0.0170.008.

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

1996-01-01

185

Photometry on Metal-Poor Stars with HST Parallaxes  

NASA Astrophysics Data System (ADS)

Stellar evolution models and isochrones of metal-poor stars are widely used in astrophysics. However, there are few observational tests of the validity of these models below metallicities of [Fe/H] = -1.5. To remedy this situation, HST has determined parallaxes for 9 metal-poor main sequence stars. Here, we present new ground-based photometry of these stars. The observations were obtained at MDM observatory in March of 2012 over the course of five nights. Our photometry is compared to literature values and combined with parallax results to obtain absolute magnitudes for these stars. The locations of the stars on a color-magnitude diagram are compared to theoretical models.

Joyce, Meridith; Chaboyer, Brian C.; Feiden, Gregory A.; Matthews, Morgan; Benedict, G. Fritz; McArthur, Barbara; Harrison, Thomas E.; McWilliam, Andrew; Nelan, Edmund P.; Patterson, Richard J.; Sarajedini, Ata

2014-06-01

186

Absolute stellar photometry on moderate-resolution FPA images  

USGS Publications Warehouse

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.

Stone, T. C.

2009-01-01

187

UBVI and Ha Photometry of the h & chi Persei cluster  

E-print Network

UBVI and Ha photometry is presented for 17319 stars in vicinity of the young double cluster h & chi Persei. Our photometry extends over a 37arcmin x 1arcdeg field centered on the association. We construct reddening contours within the imaged field. We find that the two clusters share a common distance modulus of 11.75$\\pm$0.05 and ages of log age(yr) = 7.1$\\pm$0.1. From the V-Ha colour, a measure of the Ha emission strength, we conduct a survey for emission line objects within the association. We detect a sample of 33 Be stars, 8 of which are new detections. We present a scenario of evolutionary enhancement of the Be phenomenon to account for the peak in Be fraction towards the top of the main-sequence in the population of h & chi Persei and similar young clusters.

Stefan C. Keller; Eva K. Grebel; Grant Miller; Kenneth Yoss

2001-04-10

188

The Spitzer Local Volume Legacy (LVL) global optical photometry  

NASA Astrophysics Data System (ADS)

We present the global optical photometry of 246 galaxies in the Local Volume Legacy (LVL) survey. The full volume-limited sample consists of 258 nearby (D < 11 Mpc) galaxies whose absolute B-band magnitude span a range of -9.6 < MB < -20.7 mag. A composite optical (UBVR) data set is constructed from observed UBVR and Sloan Digital Sky Survey ugriz imaging, where the ugriz magnitudes are transformed into UBVR. We present photometry within three galaxy apertures defined at UV, optical, and IR wavelengths. Flux comparisons between these apertures reveal that the traditional optical R25 galaxy apertures do not fully encompass extended sources. Using the larger IR apertures, we find colour-colour relationships where later type spiral and irregular galaxies tend to be bluer than earlier type galaxies. These data provide the missing optical emission from which future LVL studies can construct the full panchromatic (UV-optical-IR) spectral energy distributions.

Cook, David O.; Dale, Daniel A.; Johnson, Benjamin D.; Van Zee, Liese; Lee, Janice C.; Kennicutt, Robert C.; Calzetti, Daniela; Staudaher, Shawn M.; Engelbracht, Charles W.

2014-11-01

189

Estimating environmental conditions affecting protozoal pathogen removal in surface water wetland systems using a multi-scale, model-based approach.  

PubMed

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

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

190

ISOCAM Photometry of Narrow-Line X-ray Galaxies  

E-print Network

Mid-infrared photometry of the hosts of Narrow-Line X-ray Galaxies at 6 microns and 12 microns has been attempted with ISOCAM. No conclusive detections have been made. This implies that these are quiescent objects with little or no active star-formation. Neither X-ray binaries nor starburst-driven superwinds are consistent explanations for the X-ray emission in these objects. We conclude that these NLXGs are predominantly AGN-powered.

J. D. Law-Green; A. Zezas; M. J. Ward; C. Boisson

1998-12-23

191

CCD time-resolved photometry of faint cataclysmic variables. IV  

NASA Technical Reports Server (NTRS)

Time-resolved CCD photometry in V, B, and the near-IR has been obtained, with average time-series length of 3 hours, for 15 certified or candidate cataclysmic-variable faint stars. Orbital periods are found in three of the stars, and nine others are noted to exhibit evidence leading toward confirmation of cataclysmic-variable status. The characteristics of PG 0917+342 and PG 2240+193 are as yet unclear.

Howell, Steve B.; Dobrzycka, Danuta; Szkody, Paula; Kreidl, Tobias J.

1991-01-01

192

BV photographic and CCD photometry of IC 4651  

Microsoft Academic Search

A BV photometric survey in IC 4651 based on photographic and CCD material calibrated with photoelectric photometry from Eggen (1971) and Anthony-Twarog and Twarog (1987) has been completed. The color-magnitude diagram is consistent with an age of 2.4 + or - 0.3 x 10 to the 9th yr derived by comparison with the isochrones of VandenBerg (1985) if the apparent

Barbara J. Anthony-Twarog; Krishna Mukherjee; Bruce A. Twarog; Nelson Caldwell

1988-01-01

193

CCD Photometry of Galactic Globular Clusters.III.IC 4499  

Microsoft Academic Search

The variable star population of the Oosterhoff Type I galactic globular cluster IC 4499 (C1452-820) has been studied by CCD photometry, from observations in the B, V, R, and I passbands made during the period 1987-1994. Light curves have been prepared for 97 RR Lyrae variables and one variable blue-straggler (SX Phe) star. The RR Lyraes have =17.65±0.01, and via

Alistair R. Walker; James M. Nemec

1996-01-01

194

CCD Photometry of SW Ursae Majoris during the 1996 Superoutburst  

E-print Network

We present CCD R photometry of SW Ursae Majoris - an SUUMa type cataclysmic variable - obtained during its April 1996 superoutburst. The mean value of the superhump period derived from our observations is 0.05818(+/-2) days (83.8 min). The analysis of times of superhump maxima gives clear evidence for the increase of the superhump period with dPsh/dt=0.000089.

I. Semeniuk; A. Olech; T. Kwast; M. Nalezyty

1997-04-22

195

Using a Web Cam CCD to do V Band Photometry  

NASA Astrophysics Data System (ADS)

With the plethora of cheap web cam based CCD cameras in the market today, it seemed expedient to find out if they can be used to do photometry. An experiment was planned to determine if it was possible to do this kind of exacting measurement. Arne Henden (AAVSO) believed it would be possible to do V band photometry to 0.05 mag accuracy with a web cam CCD. Using a 6" refractor, the heart of M42 was repeatedly imaged. Theta 2 and SAO 132322 were the comparison stars and V361 Orion was the target variable. Since the 1/4 HAD CCD chip only allows for a field of 10x7 arc minutes using the 6" refractor, the number targets was limited. The RGB on the chip itself provides the filters needed for photometry. The G band pass on the chip ranges from 425-650 nm with a peak band pass at 540, V band pass is 475-645 with a peak at 525. The results indicate that a web cam CCD can be used for V band photometry. With a 10 second calibrated exposure without the Peltier cooling being engaged, the results for the 2 target stars were ± 0.18 mag. The star Theta 2 was 0.18 brighter in V than the actual measurement from the Tycho catalog. SAO 132322 was -0.012 mag dimmer than the listed Tycho measurement. Then using SAO 132322 and Theta 2 as comparison stars, V361 Orion was estimated at 7.786 magnitudes. This is inline with visual estimates received before and after this date. With more estimates of known magnitude comparison stars, a correction factor should be estimated and applied to the variable work that will make it more accurate. This correction factor should bring it close to Arne Henden's estimate of 0.05 mag accuracy.

Temple, Paul

2009-05-01

196

Distance to NGC 1569 via Deep HST\\/ACS Photometry  

Microsoft Academic Search

The dwarf irregular galaxy NGC 1569 is the closest and strongest starburst galaxy to the Milky Way, and contains three of the most massive super star clusters ever discovered. Using the ACS\\/WFC on the Hubble Space Telescope we have obtained the deepest optical photometry of this galaxy to date, yielding a V,I color-magnitude diagram (CMD) with some 450,000 stars. These

Aaron J. Grocholski; A. Aloisi; R. P. van der Marel; J. Mack; F. Annibali; M. Sirianni; L. Angeretti; D. Romano; M. Tosi; L. Greggio; E. V. Held

2008-01-01

197

Application of an environmental decision support system to a water quality trading program affected by surface water diversions.  

PubMed

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

Obropta, Christopher C; Niazi, Mehran; Kardos, Josef S

2008-12-01

198

How do Uncertainties in the Surface Chemical Abundances of the Sun Affect the Predicted Solar Neutrino Fluxes?  

E-print Network

We show that uncertainties in the values of the surface heavy element abundances of the Sun are the largest source of the theoretical uncertainty in calculating the p-p, pep, 8B, 13N, 15O, and 17F solar neutrino fluxes. We evaluate for the first time the sensitivity (partial derivative) of each solar neutrino flux with respect to the surface abundance of each element. We then calculate the uncertainties in each neutrino flux using `conservative (preferred)' and `optimistic' estimates for the uncertainties in the element abundances. The total conservative (optimistic) composition uncertainty in the predicted 8B neutrino flux is 11.6% (5.0%) when sensitivities to individual element abundances are used. The traditional method that lumps all abundances into a single quantity (total heavy element to hydrogen ratio, Z/X) yields a larger uncertainty, 20%. The uncertainties in the carbon, oxygen, neon, silicon, sulphur, and iron abundances all make significant contributions to the uncertainties in calculating solar neutrino fluxes; the uncertainties of different elements are most important for different neutrino fluxes. The uncertainty in the iron abundance is the largest source of the estimated composition uncertainties of the important 7Be and 8B solar neutrinos. Carbon is the largest contributor to the uncertainty in the calculation of the p-p, 13N, and 15O neutrino fluxes. However, for all neutrino fluxes, several elements contribute comparable amounts to the total composition uncertainty.

John N. Bahcall; Aldo M. Serenelli

2004-12-03

199

Hydrologic characterization of a permafrost-affected headwaters catchment using a coupled groundwater-surface water model and field measurements of active layer characteristics  

NASA Astrophysics Data System (ADS)

Permafrost degradation is expected to change the quantity and quality of solute fluxes from northern watersheds. In particular, fluxes of organic carbon (OC) and mercury (Hg) are of great concern for aquatic and marine ecosystems in this area. The total export of OC and Hg depends upon hydrology of permafrost-affected catchments; in particular, the magnitude and extent of groundwater-surface water flows. Hydrologic processes in these catchments are complex and poorly understood; furthermore, understanding of groundwater-surface water interaction is greatly complicated by permafrost degradation. Hydrologic modeling and field studies at West Twin Creek - a permafrost-affected, experimental headwaters catchment in interior Alaska - have been undertaken to identify the dominant controls upon catchment hydrology, groundwater-surface water interaction, and export of OC and Hg. A coupled groundwater-surface water model was developed using the code GSFLOW, calibrated to several years of streamflow data. Sensitivity analysis revealed that groundwater-surface water flows are predominantly controlled by physical characteristics of the soil active layer in the catchment. A suite of measurements was designed to better constrain the properties of the soil active layer at West Twin Creek during a period of maximum thaw depth. Gridded permafrost probing and soil coring were undertaken along several transects through hillslope and riparian areas. Ground-penetrating radar (GPR) surveys were conducted to complement these point measurements, providing spatially continuous information on active layer thickness along survey lines. Soil coring and GPR surveys revealed distinct soil profiles and frost table depths at several hillslope locations. Soils varied from fine eolian silts to coarse schist cobbles, and differences corresponded to moisture, surface vegetation, and thaw depth. These differences may have large effects on moisture storage, hillslope hydraulic conductivity, and subsequently runoff potential. Artificial rainfall experiments were then performed to quantify surface runoff and interflow through organic and mineral horizons at control plots representative of each soil profile type. These experiments showed that water flow occurs predominantly at the interface between organic and mineral horizons in hillslope soils. The targeted measurements undertaken during this field campaign were used to revise the hydrologic model for the catchment, providing more accurate estimates of groundwater-surface water fluxes for the purposes of forecasting OC and Hg exports.

Kikuchi, C.; Koch, J.; Steelman, C. M.; Schuster, P. F.

2012-12-01

200

Identifying Contaminated K-Band Globular Cluster RR Lyrae Photometry  

NASA Astrophysics Data System (ADS)

Acquiring near-infrared K-band (2.2 ?m) photometry for RR Lyrae variables in globular clusters and nearby galaxies is advantageous, since the resulting distances are less impacted by reddening and metallicity. However, K-band photometry for RR Lyrae variables in M5, Reticulum, M92, ? Cen, and M15 display clustercentric trends. The Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) data imply that multiple stars in close proximity to RR Lyrae variables located near the cluster core, where the stellar density increases markedly, are generally unresolved in ground-based images. RR Lyrae variables near the cluster core appear to suffer from photometric contamination, thereby yielding underestimated cluster distances and biased ages. The impact is particularly pernicious, since the contamination propagates a systematic uncertainty into the distance scale, and hinders the quest for precision cosmology. The clustercentric trends are probably unassociated with variations in chemical composition, since an empirical K-band period-magnitude relation inferred from Araucaria/VLT (Very Large Telescope) data for RR Lyrae variables in the Sculptor dSph exhibits a negligible metallicity dependence: (0.059 ± 0.095) × [Fe/H]ZW, a finding that supports prior observational results. A future multiepoch, high-resolution near-infrared survey, analogous to the optical HST ACS Galactic Globular Cluster Survey, may be employed to establish K-band photometry for the contaminating stars discussed here.

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

2012-10-01

201

M2K Planet Search: Spectroscopic Screening and Transit Photometry  

NASA Astrophysics Data System (ADS)

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.

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

2010-10-01

202

ULTRACAM photometry of the eclipsing cataclysmic variables XZ Eri and DV UMa  

NASA Astrophysics Data System (ADS)

We present high-speed, three-colour photometry of the faint eclipsing cataclysmic variables XZ Eri and DV UMa. We determine the system parameters through two techniques: first, timings of the eclipse contact phases of the white dwarf and bright-spot using the derivative of the light curve; and secondly, a parametrized model of the eclipse fitted to the observed light curve by ?2 minimization. For both objects, we prefer the latter method, as it is less affected by photon noise and rapid flickering. For XZ Eri we obtain a mass ratio q= 0.1098 +/- 0.0017 and an orbital inclination . For DV UMa we derive figures of q= 0.1506 +/- 0.0009 and . The secondary star in XZ Eri has a very low mass Mr/Msolar= 0.0842 +/- 0.0024, placing it close to the upper limit on the mass of a brown dwarf.

Feline, W. J.; Dhillon, V. S.; Marsh, T. R.; Brinkworth, C. S.

2004-11-01

203

Apatite formation on bioactive calcium-silicate cements for dentistry affects surface topography and human marrow stromal cells proliferation.  

PubMed

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

Gandolfi, Maria Giovanna; Ciapetti, Gabriela; Taddei, Paola; Perut, Francesca; Tinti, Anna; Cardoso, Marcio Vivan; Van Meerbeek, Bart; Prati, Carlo

2010-10-01

204

The impact of main belt asteroids on infrared--submillimetre photometry and source counts  

E-print Network

> Among the components of the infrared and submillimetre sky background, the closest layer is the thermal emission of dust particles and minor bodies in the Solar System. This contribution is especially important for current and future infrared and submillimetre space instruments --like those of Spitzer, Akari and Herschel -- and must be characterised by a reliable statistical model. > We describe the impact of the thermal emission of main belt asteroids on the 5...1000um photometry and source counts, for the current and future spaceborne and ground-based instruments, in general, as well as for specific dates and sky positions. > We used the statistical asteroid model (SAM) to calculate the positions of main belt asteroids down to a size of 1km, and calculated their infrared and submillimetre brightness using the standard thermal model. Fluctuation powers, confusion noise values and number counts were derived from the fluxes of individual asteroids. > We have constructed a large database of infrared and submillimetre fluxes for SAM asteroids with a temporal resolution of 5 days, covering the time span January 1, 2000 -- December 31, 2012. Asteroid fluctuation powers and number counts derived from this database can be obtained for a specific observation setup via our public web-interface. > Current space instruments working in the mid-infrared regime (Akari and Spitzer Space Telescopes) are affected by asteroid confusion noise in some specific areas of the sky, while the photometry of space infrared and submillimetre instruments in the near future (e.g. Herschel and Planck Space Observatories) will not be affected by asteroids. Faint main belt asteroids might also be responsible for most of the zodiacal emission fluctuations near the ecliptic.

Cs. Kiss; A. Pal; Th. G. Mueller; P. Abraham

2007-11-24

205

Synthetic Spectroscopy and Photometry for the Sun  

NASA Astrophysics Data System (ADS)

The availability of a digital version of the solar line spectrum (Kitt Peak Preliminary Solar Atlas, Brault & Testerman 1972) has made it possible to carry out detailed comparisons of observed and synthetic spectra. The more accurately the spectrum of the Sun, and other standard stars, can be reproduced, the more likely the line list is to give reliable results in other applications. Detailed comparisons have been made using three lists. The first two are: 1) One which has been used repeatedly by the author and collaborators e.g. Bell, Dickens & Gustafsson (ApJ,229,604,1979); Tripicco & Bell (AJ,103,1285,1992); 2) One derived from Kurucz (Stellar Atmospheres: Beyond Classical Models, Kluwer, Dordrecht, p408,1991) for elements between Ca and Ni, supplemented with lines for other elements from Kurucz & Peytremann (SAO Spec Rept 362,1975) and molecular lines from the author's list (e.g. Bell & Gustafsson MNRAS,236,653,1989). The Kurucz list predicts many lines in the solar spectrum which are either not seen or are observed to be far weaker. The errors in oscillator strength may exceed a factor of 10. On the other hand, there are not a corresponding number of lines which are observed but which are not present in the synthetic spectra. Needless to say, this excess in the computed line absorption will affect the calculation of both model atmospheres and synthetic magnitudes. For example, the computed U-B colors will be too red. In view of these errors, and the much better fit which spectra calculated using the author's lists give to the solar line spectrum, the Kurucz list has been used only to fill in gaps in the author's list, thereby creating a third list. This list also incorporates new laboratory gf values (e.g. O'Brian et al. JOSA B,8,1185,1991). Detailed comparisons of observed and synthetic solar spectra from the different lists are shown.

Bell, R. A.

1993-05-01

206

Galileo photometry of asteroid 243 Ida  

USGS Publications Warehouse

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.

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

207

High-Quality Broadband BVRI Photometry of Benchmark Open Clusters  

NASA Astrophysics Data System (ADS)

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.

Joner, Michael D.

208

BV photometry of five shell galaxies  

NASA Astrophysics Data System (ADS)

Current views consider shell structures as bona fide signatures of a recent minor/major merging event though also weak interaction models (WIM) could produce long lasting shells on host galaxies possessing a stellar thick disc. We present a B V band photometric study of a sample of 5 shell galaxies belonging to the Malin & Carter (1983) compilation. The structural properties and colors of the galaxies, as well as the colors of their shells are examined in detail. We did not find signatures of the presence of double nuclei. NGC 7585 is the only E galaxy in the sample and has a moderately boxy structure. The other galaxies have either a discy structure or are mixed E/S0 type galaxies. NGC 474 is a true lenticular. NGC 6776 shows a diffuse asymmetric outer structure and a system of tails of the the same color of the galaxy body; but not clear shells. In general, the color of the shells in our sample is similar or slightly redder than that of the host galaxy, whose color, in turn, is typical of the early-type morphological class. One of the outer shells of NGC 474 is significantly bluer than the body of the galaxy. Since NGC 474 appears to be interacting with NGC 470, the color of this one shell could be explained as result of a recent acquisition of material through tidal interaction. The WIM hypothesis could explain both the red and the blue shells of NGC 474, this latter acquired from the fly-by of the nearby companion NGC 470, but the lack of the constancy of shell surface brightness as a ratio of the underlying galaxy brightness argues against WIM. We speculate about evidence, which also comes from different observations, that suggests a merging/accretion origin of the shells. Based on observations obtained at the Observatoire de Haute Provence, CNRS, Saint Michel l'Observatoire, France and ESO, La Silla, Chile

Pierfederici, F.; Rampazzo, R.

2004-06-01

209

Would the heat of an oil pipeline buried 4 feet underground affect ground or surface water temperature or the roots of typical Nebraska crops like corn, soybeans, alfalfa? Would  

E-print Network

1 Crops Would the heat of an oil pipeline buried 4 feet underground affect ground or surface water of the plant roots are close to the surface (say within a couple of feet); but a few roots do reach deeper temperatures throughout the rooting zone (from the surface to, say, 4-5 feet deep) then, yes, there would most

Nebraska-Lincoln, University of

210

VizieR Online Data Catalog: Galaxies morphology and IR photometry II. (Gavazzi+ 1996)  

NASA Astrophysics Data System (ADS)

We present near-infrared H-band (1.65?m) surface photometry of 297 galaxies (mostly) in the Coma Supercluster obtained with the Arcetri NICMOS3 camera, ARNICA, mounted on the Gornergrat Infrared Telescope. Magnitudes and diameters within the 21.5mag/arcsec2 isophote, concentration indices, and total H magnitudes are derived. Combining these observations with those obtained similarly using the Calar Alto telescopes (Paper I, ) we find a strong positive correlation between the near-infrared concentration index and the galaxy H-band luminosity, and we analyze the consequent dependence of near-infrared growth-curves on H-band luminosity. For a description of the H band photometric system, see e.g. (2 data files).

Gavazzi, G.; Pierini, D.; Baffa, C.; Lisi, F.; Hunt, L. K.; Randone, I.; Boselli, A.

1996-05-01

211

A 3D extinction map of the northern Galactic plane based on IPHAS photometry  

NASA Astrophysics Data System (ADS)

We present a 3D map of extinction in the northern Galactic plane derived using photometry from the INT/WFC Photometric H? Survey of the northern Galactic plane. The map has fine angular ( ˜ 10 arcmin) and distance (100 pc) sampling allied to a significant depth (?5 kpc). We construct the map using a method based on a hierarchical Bayesian model described in a previous article by Sale. In addition to mean extinction, we also measure differential extinction, which arises from the fractal nature of the interstellar medium, and show that it will be the dominant source of uncertainty in estimates of extinction to some arbitrary position. The method applied also furnishes us with photometric estimates of the distance, extinction, effective temperature, surface gravity, and mass for ˜38 million stars. Both the extinction map and the catalogue of stellar parameters are made publicly available via http://www.iphas.org/extinction.

Sale, S. E.; Drew, J. E.; Barentsen, G.; Farnhill, H. J.; Raddi, R.; Barlow, M. J.; Eislöffel, J.; Vink, J. S.; Rodríguez-Gil, P.; Wright, N. J.

2014-10-01

212

Temperature-Induced Changes in the Lipopolysaccharide of Yersinia pestis Affect Plasminogen Activation by the Pla Surface Protease?  

PubMed Central

The Pla surface protease of Yersinia pestis activates human plasminogen and is a central virulence factor in bubonic and pneumonic plague. Pla is a transmembrane ?-barrel protein and member of the omptin family of outer membrane proteases which require bound lipopolysaccharide (LPS) to be proteolytically active. Plasminogen activation and autoprocessing of Pla were dramatically higher in Y. pestis cells grown at 37°C than in cells grown at 20°C; the difference in enzymatic activity by far exceeded the increase in the cellular content of the Pla protein. Y. pestis modifies its LPS structure in response to growth temperature. We purified His6-Pla under denaturing conditions and compared various LPS types for their capacity to enhance plasmin formation by His6-Pla solubilized in detergent. Reactivation of His6-Pla was higher with Y. pestis LPSs isolated from bacteria grown at 37°C than with LPSs from cells grown at 25°C. Lack of O antigens and the presence of the outer core region as well as a lowered level of acylation in LPS were found to enhance the Pla-LPS interaction. Genetic substitution of arginine 138, which is part of a three-dimensional protein motif for binding to lipid A phosphates, decreased both the enzymatic activity of His6-Pla and the amount of Pla in Y. pestis cells, suggesting the importance of the Pla-lipid A phosphate interaction. The temperature-induced changes in LPS are known to help Y. pestis to avoid innate immune responses, and our results strongly suggest that they also potentiate Pla-mediated proteolysis. PMID:20368351

Suomalainen, Marjo; Lobo, Leandro Araujo; Brandenburg, Klaus; Lindner, Buko; Virkola, Ritva; Knirel, Yuriy A.; Anisimov, Andrey P.; Holst, Otto; Korhonen, Timo K.

2010-01-01

213

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)

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.

Rosenblad, B. L.; Bay, J. A.

2008-05-01

214

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

NASA Technical Reports Server (NTRS)

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.

Prosser, Charles F.

1994-01-01

215

MOST photometry of the enigmatic PMS pulsator HD 142666  

NASA Astrophysics Data System (ADS)

Context: Modeling of pre-main sequence (PMS) stars through asteroseismology of PMS p-mode pulsators has only recently become possible, and spacebased photometry is one of the important sources of data for these efforts. We present precise photometry of the pulsating Herbig Ae star HD 142666 obtained in two consecutive years with the MOST (Microvariability & Oscilations of STars) satellite. Aims: Previously, only a single pulsation period was known for HD 142666. The MOST photometry reveals that HD 142666 is multi-periodic. However, the unique identification of pulsation frequencies is complicated by the presence of irregular variability caused by the star's circumstellar dust disk. The two light curves obtained with MOST in 2006 and 2007 provided data of unprecedented quality to study the pulsations in HD 142666 and also to monitor the circumstellar variability. Methods: Frequency analysis was performed using the routine sigspec and the results from the 2006 and 2007 campaigns were then compared to each other with the software cinderella to identify frequencies common to both light curves. The correlated frequencies were then submitted to an asteroseismic analysis. Results: We attribute 12 frequencies to pulsation. Model fits to the three frequencies with the highest amplitudes lie well outside the uncertainty box for the star's position in the HR diagram based on published values. Some of the frequencies appear to be rotationally split modes. Conclusions: The models suggest that either (1) the published estimate of the luminosity of HD 142666, based on a relation between circumstellar disk radius and stellar luminosity, is too high and/or (2) additional physics such as mass accretion may be needed in our models to accurately fit both the observed frequencies and HD 142666's position in the HR diagram. Based on data from the MOST satellite, a Canadian Space Agency mission, jointly operated by Dynacon Inc., the University of Toronto Institute for Aerospace Studies and the University of British Columbia with the assistance of the University of Vienna.

Zwintz, K.; Kallinger, T.; Guenther, D. B.; Gruberbauer, M.; Huber, D.; Rowe, J.; Kuschnig, R.; Weiss, W. W.; Matthews, J. M.; Moffat, A. F. J.; Rucinski, S. M.; Sasselov, D.; Walker, G. A. H.; Casey, M. P.

2009-02-01

216

Cool White Dwarfs Revisited -- New Spectroscopy and Photometry  

E-print Network

In this paper we present new and improved data on 38 cool white dwarfs identified by Oppenheimer et al. 2001 (OHDHS) as candidate dark halo objects. Using the high-res spectra obtained with LRIS, we measure radial velocities for 13 WDs that show an H alpha line. We show that the knowledge of RVs decreases the UV-plane velocities by only 6%. The radial velocity sample has a W-velocity dispersion of sig_W = 59 km/s--in between the values associated with the thick disk and the stellar halo. We also see indications for the presence of two populations by analyzing the velocities in the UV plane. In addition, we present CCD photometry for half of the sample, and with it recalibrate the photographic photometry of the remaining WDs. Using the new photometry in standard bands, and by applying the appropriate color-magnitude relations for H and He atmospheres, we obtain new distance estimates. New distances of the WDs that were not originally selected as halo candidates yield 13 new candidates. On average, new distances produce velocities in the UV plane that are larger by 10%, with already fast objects gaining more. Using the new data, while applying the same UV-velocity cut (94 km/s) as in OHDHS, we find a density of cool WDs of 1.7e-4 pc^-3, confirming the value of OHDHS. In addition, we derive the density as a function of the UV-velocity cutoff. The density (corrected for losses due to higher UV cuts) starts to flatten out at 150 km/s (0.4e-4 pc^-3), and is minimized (thus minimizing a possible non-halo contamination) at 190 km/s (0.3e-4 pc^-3). These densities are in a rough agreement with the estimates for the stellar halo WDs, corresponding to a factor of 1.9 and 1.4 higher values.

Samir Salim; R. Michael Rich; Brad M. Hansen; L. V. E. Koopmans; Ben R. Oppenheimer; Roger D. Blandford

2003-08-07

217

Photometry and spectroscopy in the open cluster Alpha Persei, 2  

NASA Technical Reports Server (NTRS)

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.

Prosser, Charles F.

1993-01-01

218

Multicolor Photometry of the Merging Galaxy Cluster A2319: Dynamics and Star Formation Properties  

NASA Astrophysics Data System (ADS)

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.

Yan, Peng-Fei; Yuan, Qi-Rong; Zhang, Li; Zhou, Xu

2014-05-01

219

A digital imaging photometry system for cometary data acquisition  

NASA Technical Reports Server (NTRS)

This report describes a digital imaging photometry system developed in the Space Science Laboratory at the Marshall Space Flight center. The photometric system used for cometary data acquisition is based on an intensified secondary electron conduction (ISEC) vidicon coupled to a versatile data acquisition system which allows real-time interactive operation. Field tests on the Orion and Rosette nebulas indicate a limiting magnitude of approximately m sub v = 14 over the 40 arcmin field-of-view. Observations were conducted of Comet Giacobini-Zinner in August 1985. The resulting data are discussed in relation to the capabilities of the digital analysis system. The development program concluded on August 31, 1985.

Clifton, K. S.; Benson, C. M.; Gary, G. A.

1986-01-01

220

UBVRI photometry of the FK5 Extension Catalogue Stars  

NASA Astrophysics Data System (ADS)

UBVRI photometry in the Kron-Cousins system for 272 stars of the Extension Catalogue of the Fifth Fundamental Star Catalogue (FK5 stars) in the declination zone +7 deg to -90 deg is presented. Tables 1-2 are also 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 Based on observations made at the European Southern Observatory, La Silla, Chile.

Carrasco, G.; Ledoux, C.; Loyola, P.

1997-12-01

221

Photometry and Modelling of Tidal Dwarfs around AM Galaxies  

NASA Astrophysics Data System (ADS)

Tidal dwarf galaxies (TDGs) are a class of objects born from preenriched material in the tails of interacting and merging galaxies. The recent study of a small number of TDGs showed common properties in metallicity, blue colors, and H i-gas content. This study aims to a larger statistics of TDGs. Therefore we present B, V, R photometry of TDG-candidates in a sample of objects from the AM catalog. The modelling of the resulting colors through evolutionary synthesis is used for the interpretation regarding burst age, metallicity, and relative proportions of the old and young starburst components.

Weilbacher, P. M.; Duc, P.-A.; Fritze-v. Alvensleben, U.; Fricke, K. J.

222

U-band photometry of 17 WINGS clusters  

NASA Astrophysics Data System (ADS)

Context. This paper belongs to a series presenting the WIde Field Nearby Galaxy-cluster Survey (WINGS). The WINGS project has collected wide-field, optical (B, V), and near-infrared (J, K) imaging as well as medium resolution spectroscopy of galaxies in a sample of 76 X-ray selected nearby clusters (0.04 photometry of galaxies and stars in the fields of 17 clusters of the WINGS sample. We also extend the original B- and V-band photometry (WINGS-OPT) for 9 and 6 WINGS clusters to a larger field of view. Methods: We used both the new and already existing B-band photometry to obtain reliable (U - B) colors of galaxies within three fixed apertures in kpc. To this aim, we took particular care with the astrometric precision in the reduction procedure. Since not all the observations were taken in good transparency conditions, the photometric calibration was partly obtained by relying on the SDSS and WINGS-OPT photometry for the U- and optical bands, respectively. Results: We provide U-band (also B- and V-band, where possible) total magnitudes of stars and galaxies in the fields of clusters. For galaxies only, the catalogs also provide geometrical parameters and carefully centered aperture magnitudes. The internal consistency of magnitudes was checked for clusters imaged with different cameras, while the external photometric consistency was obtained by comparison with the WINGS-OPT and SDSS surveys. Conclusions: The photometric catalogs presented here add the U-band information to the WINGS database for extending the spectral energy distribution of the galaxies, in particular in the ultraviolet wavelengths which are fundamental for deriving the star formation rate properties. Photometric 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/561/A111

Omizzolo, A.; Fasano, G.; Reverte Paya, D.; De Santis, C.; Grado, A.; Bettoni, D.; Poggianti, B.; D'Onofrio, M.; Moretti, A.; Varela, J.; Fritz, J.; Gullieuszik, M.; Cava, A.; Grazian, A.; Moles, M.

2014-01-01

223

CCD Photometry of Dwarf Nova AL Com in Superoutburst  

E-print Network

We report a CCD optical photometry of a dwarf nova AL Com in superoutburst. Before superhumps occurred the light curve was highly variable with dominant periods about 41 minutes and 81.5 minutes for different nights. The period of observed superhumps is 82.5 minutes and seems to be stable. The first harmonic of the basic period is also present. We detected a weak signal corresponding to period 78.1 minutes. One of the periods 78.1 or 81.5 is suspected to be a possible signature of orbital motion in the system.

W. Pych; A. Olech

1995-09-20

224

CCD-Delta a and BVR photometry of NGC 7296  

E-print Network

The first CCD photometric investigation of the open cluster NGC 7296 up to now was performed within the narrow band Delta a photometric system, which enables us to detect peculiar objects. A deeper investigation of that cluster followed, using the standard BVR-Bessel filter set. The age and E(B-V) was determined independently to log t= 8.0 and 0.15 respectively by using Delta a and broadband photometry. In total five Be/Ae objects and two metal-weak stars showing significant negative Delta a-values as well as one classical chemically peculiar star could be identified within that intermediate age open cluster.

M. Netopil; E. Paunzen; H. M. Maitzen; A. Claret; K. Pavlovski; E. Tamajo

2005-07-25

225

Photometry and polarimetry of pre-main sequence stars  

NASA Astrophysics Data System (ADS)

We present optical and infrared photometry, and optical polarimetry, of several pre-main sequence stars; much of the data were obtained quasi-simultaneously. Our data demonstrate that, while a simple occultation model for deep visual minima in pre-main sequence stars is consistent with the data in some cases, in others a major change in the outer dust shell is required to account for the optical-infrared behaviour. Apart from the marginal case of UX Ori, there is no significant correlation between polarization and photometric colours. We tentatively report the possible detection of circular polarization in AK Sco, RU Lup, HD97048 and HD144667.

Hutchinson, M. G.; Albinson, J. S.; Barrett, P.; Davies, J. K.; Evans, A.; Goldsmith, M. J.; Maddison, R. C.

1994-05-01

226

Broadband Photometry of the Potentially Hazardous Asteroid 2013 RH74  

NASA Astrophysics Data System (ADS)

The Near-Earth Asteroid (NEA) 2013 RH74 was discovered by the Catalina Sky Survey on September 15 2013 (MPEC 2013-S15) and has been designated as a Potentially Hazardous Asteroid (PHA) by the Minor Planet Center. We obtained six partial nights of broadband Bessel BVRI photometry at the JPL Table Mountain 0.6-m telescope (TMO), as summarized in Table 1. This object was detected by planetary radar soon after discovery (http://echo.jpl.nasa.gov/asteroids/index.html).

Hicks, M.; Ebelhar, S.

2013-11-01

227

Broadband Photometry of the Potentially Hazardous Asteroid 251346 (2007 SJ)  

NASA Astrophysics Data System (ADS)

The Near-Earth Asteroid (NEA) 251346 (2007 SJ) was discovered by the LINEAR Sky Survey on September 17, 2007 (MPEC 2007-S17). With a Minimum Orbit Intersection Distance (MOID) of 0.045 AU and an expected diameter between 1.3~2.8 km, this object has been designated as a Potentially Hazardous Asteroid (PHA) by the Minor Planet Center. We obtained two partial nights of broadband Bessel BVRI photometry (October 10 and December 11, 2013) and one night (December 13, 2013) at the JPL Table Mountain 0.6-m telescope (TMO), as summarized in Table 1.

Hicks, M.; Ebelhar, S.

2014-01-01

228

Near-IR Spectroscopy and Visual Broadband Photometry of Unbound Asteroid Pairs  

NASA Astrophysics Data System (ADS)

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.

Wolters, Stephen D.; Weissman, P.; Duddy, S. R.; Christou, A.; Green, S. F.; Lowry, S. C.; Rozitis, B.

2012-10-01

229

BVI CCD photometry of the globular cluster M4  

SciTech Connect

CCD BV1 main-sequence (MS) photometry of M4, the globular cluster closest to the sun, is presented. The photometry is matched to the BVI isochrones of VandenBerg and Bell (1985). The MS turnoffs are found to be at V = 16.90 + or - 0.05, B-V = 0.81 + or - 0.02, V-I = 0.96 + or - 0.02, and B - I = 1.77 + or - 0.02. The magnitude difference between the MS turnoff and the horizontal branch is Delta M(V) = 3.52 + or - 0.1 for all three color indices. Using Y = 0.2, (Fe/H) = - 1.27, and alpha = 1.65, with a distance modulus of (m-M)V = 12.7 and E(B-V) = 0.41, a consistent age for M4 is deduced in all three color indices of 17 + or - 1.5 Gyr. 34 references.

Alcaino, G.; Liller, W.; Alvarado, F.

1988-07-01

230

Macular Pigment Optical Density Measured by Heterochromatic Modulation Photometry  

PubMed Central

Purpose To psychophysically determine macular pigment optical density (MPOD) employing the heterochromatic modulation photometry (HMP) paradigm by estimating 460 nm absorption at central and peripheral retinal locations. Methods For the HMP measurements, two lights (B: 460 nm and R: 660 nm) were presented in a test field and were modulated in counterphase at medium or high frequencies. The contrasts of the two lights were varied in tandem to determine flicker detection thresholds. Detection thresholds were measured for different R:B modulation ratios. The modulation ratio with minimal sensitivity (maximal threshold) is the point of equiluminance. Measurements were performed in 25 normal subjects (11 male, 14 female; age: 30±11 years, mean ± sd) using an eight channel LED stimulator with Maxwellian view optics. The results were compared with those from two published techniques – one based on heterochromatic flicker photometry (Macular Densitometer) and the other on fundus reflectometry (MPR). Results We were able to estimate MPOD with HMP using a modified theoretical model that was fitted to the HMP data. The resultant MPODHMP values correlated significantly with the MPODMPR values and with the MPODHFP values obtained at 0.25° and 0.5° retinal eccentricity. Conclusions HMP is a flicker-based method with measurements taken at a constant mean chromaticity and luminance. The data can be well fit by a model that allows all data points to contribute to the photometric equality estimate. Therefore, we think that HMP may be a useful method for MPOD measurements, in basic and clinical vision experiments. PMID:25354049

Huchzermeyer, Cord; Schlomberg, Juliane; Welge-Lüssen, Ulrich; Berendschot, Tos T. J. M.; Pokorny, Joel; Kremers, Jan

2014-01-01

231

Multicolor photometry of triple system b Per requested  

NASA Astrophysics Data System (ADS)

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.

Waagen, Elizabeth O.

2013-01-01

232

PHOTOMETRY OF VARIABLE STARS FROM DOME A, ANTARCTICA  

SciTech Connect

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.

Wang Lingzhi [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Macri, Lucas M.; Krisciunas, Kevin; Wang Lifan [Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Ashley, Michael C. B.; Lawrence, Jon S.; Luong-Van, Daniel; Storey, John W. V. [School of Physics, University of New South Wales, NSW 2052 (Australia); Cui Xiangqun; Gong Xuefei; Yuan Xiangyan [Nanjing Institute of Astronomical Optics and Technology, Nanjing 210042 (China); Feng Longlong; Yang Ji; Zhu Zhenxi [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Liu Qiang; Zhou Xu [National Astronomical Observatory of China, Chinese Academy of Sciences, Beijing 100012 (China); Pennypacker, Carl R. [Center for Astrophysics, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Shang Zhaohui [Department of Physics, Tianjin Normal University, Tianjin 300074 (China); Yang Huigen [Polar Research Institute of China, Pudong, Shanghai 200136 (China); York, Donald G. [Department of Astronomy and Astrophysics and Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 (United States)

2011-11-15

233

Stellar Photometry and Astrometry with Discrete Point Spread Functions  

E-print Network

The key features of the MATPHOT algorithm for precise and accurate stellar photometry and astrometry using discrete Point Spread Functions are described. A discrete Point Spread Function (PSF) is a sampled version of a continuous PSF which describes the two-dimensional probability distribution of photons from a point source (star) just above the detector. The shape information about the photon scattering pattern of a discrete PSF is typically encoded using a numerical table (matrix) or a FITS image file. Discrete PSFs are shifted within an observational model using a 21-pixel-wide damped sinc function and position partial derivatives are computed using a five-point numerical differentiation formula. Precise and accurate stellar photometry and astrometry is achieved with undersampled CCD observations by using supersampled discrete PSFs that are sampled 2, 3, or more times more finely than the observational data. The precision and accuracy of the MATPHOT algorithm is demonstrated by using the C-language MPD code to analyze simulated CCD stellar observations; measured performance is compared with a theoretical performance model. Detailed analysis of simulated Next Generation Space Telescope observations demonstrate that millipixel relative astrometry and millimag photometric precision is achievable with complicated space-based discrete PSFs. For further information about MATPHOT and MPD, including source code and documentation, see http://www.noao.edu/staff/mighell/matphot

Kenneth J. Mighell

2005-05-20

234

Photometry of Variable Stars from Dome A, Antarctica  

E-print Network

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 square-degree 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 find 6 times as many variables as previous surveys with similar magnitude limits. We detected 157 variable stars, of which 55% are unclassified, 27% are likely binaries and 17% are likely pulsating stars. The latter category includes delta Scuti, gamma Doradus and RR Lyrae variables. One variable may be a transiting exoplanet.

Wang, Lingzhi; Krisciunas, Kevin; Wang, Lifan; Ashley, Michael C B; Cui, Xiangqun; Feng, Long-Long; Gong, Xuefei; Lawrence, Jon S; Liu, Qiang; Luong-Van, Daniel; Pennypacker, Carl R; Shang, Zhaohui; Storey, John W V; Yang, Huigen; Yang, Ji; Yuan, Xiangyan; York, Donald G; Zhou, Xu; Zhu, Zhenxi

2011-01-01

235

Infrared spectroscopy and photometry of Comet Austin 1990 V  

NASA Technical Reports Server (NTRS)

3-micron and 10-micron spectra and IR photometry of the dynamically new Comet Austin 1990 V were obtained for March-May 1990. An unusual 9-11 micron emission feature 15-20 percent above the continuum is evident at 0.78 AU postperihelion. The shape, in particular a peak at 11.06 micron, differs from that seen in Halley and several other comets, suggesting a difference in the mineralogy of the silicate grains. The 3.1-7.7 micron spectrum at 0.35 AU shows no obvious feature; feature/continuum contrast of the 3.36 micron emission feature is less than about 5 percent. Based on the IR photometry and a dust model weighted toward small grains, the dust production rate on 6 May at 0.78 AU was about 3 x 10 exp 5 g/s. The corresponding dust/gas mass ratio was about 0.1, classifying Austin as a dust-poor comet. This designation refers only to the relative dust cross section, not to the total mass.

Hanner, Martha S.; Russell, Ray W.; Lynch, David K.; Brooke, Timothy Y.

1993-01-01

236

Macho Proper Motions From Optical/Infrared Photometry  

E-print Network

Optical/infrared photometry can double the number of proper motion measurements of Massive Compact Objects (MACHOs) relative to single band photometry. The proper motion of a MACHO can be measured by finding the ratio $q$ of the (known) radius of the source star to the Einstein radius of the MACHO, $q=\\theta_s/\\theta_e$. A classic method for doing this is to look for the effect on the light curve of the finite size of the source. A modification of this method proposed by Witt (1995) is to look for color changes in the light curve due to the fact that the limb darkening of the source is different in different bands. We demonstrate that the ``classical'' method is not feasible unless the MACHO actually transits the source: if the MACHO passes at say 1.5 source radii, there is still a sizable $\\sim 5\\%$ effect, but the light curve cannot be distinguished from point-source light curves with different parameters. However, color measurements in $V$ $(0.55\\,\\mu$m) and $H$ $(1.65\\,\\mu$m) reduce the errors by a factor $\\sim 120$ and permit proper motion measurements at impact parameters of up to 2 source radii. Color maps in $V-H$ are also useful in the detection of planetary systems. Giant stars have a ``red ring'' in such maps. A planet which transits this ring gives rise to a distinctive signature which can help in the measurement of the planetary system's proper motion.

Andrew Gould; Douglas L. Welch

1995-06-07

237

Improving the Photometry of the Pi of the Sky System  

NASA Astrophysics Data System (ADS)

The "Pi of the Sky" robotic telescope was designed to monitor a significant fraction of the sky with good time resolution and range. The main goal of the "Pi of the Sky" detector is to look for short timescale optical transients arising from various astrophysical phenomena, mainly for the optical counterparts of Gamma Ray Bursts (GRB). The system design, the observation methodology and the algorithms that have been developed make this detector a sophisticated instrument for looking for novae and supernovae stars and for monitoring blasars and AGNs activity. The final detector will consist of two sets of 12 cameras, one camera covering a field of view of 20° × 20°. For data taken with the prototype detector at the Las Campanas Observatory, Chile, photometry uncertainty of 0.018-0.024 magnitudo for stars 7-10m was obtained. With a new calibration algorithm taking into account the spectral type of reference stars, the stability of the photometry algorithm can be significantly improved. Preliminary results from the BGInd variable are presented, showing that uncertainty of the order of 0.013 can be obtained.

?arnecki, A. F.; Ma?ek, K.; Soko?owski, M.

238

Optimal Addition of Images for Detection and Photometry  

E-print Network

In this paper we describe weighting techniques used for the optimal coaddition of CCD frames with differing characteristics. Optimal means maximum signal-to-noise (s/n) for stellar objects. We derive formulae for four applications: 1) object detection via matched filter, 2) object detection identical to DAOFIND, 3) aperture photometry, and 4) ALLSTAR profile-fitting photometry. We have included examples involving 21 frames for which either the sky brightness or image resolution varied by a factor of three. The gains in s/n were modest for most of the examples, except for DAOFIND detection with varying image resolution which exhibited a substantial s/n increase. Even though the only consideration was maximizing s/n, the image resolution was seen to improve for most of the variable resolution examples. Also discussed are empirical fits for the weighting and the availability of the program, WEIGHT, used to generate the weighting for the individual frames. Finally, we include appendices describing the effects of clipping algorithms and a scheme for star/galaxy and cosmic ray/star discrimination.

Philippe Fischer; Greg P. Kochanski

1993-10-14

239

A new look at photometry of the Moon  

USGS Publications Warehouse

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.

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

2010-01-01

240

VizieR Online Data Catalog: CU Vir Stroemgren differential photometry (Pyper+, 2013)  

NASA Astrophysics Data System (ADS)

Our data are from two sources: Stroemgren differential uvby photometry obtained using the Four College Automated Photometric Telescope (FCAPT) originally on Mt. Hopkins, AZ, and later at Fairborn Observatory, Washington Camp, AZ, and photometry from the Solar Mass Ejection Imager (SMEI). (1 data file).

Pyper, D. M.; Stevens, I. R.; Adelman, S. J.

2014-06-01

241

Achieving high-precision ground-based photometry for transiting exoplanets  

E-print Network

Achieving high-precision ground-based photometry for transiting exoplanets Olivier Guyona, USA ABSTRACT Detection of transiting exoplanets requires high precision photometry, at the percent opportunity for exoplanet transit detection. We have recently assembled a prototype DSLR-based robotic imaging

Guyon, Olivier

242

VizieR Online Data Catalog: Metallicity calibrations for UBV photometry (Karatas+, 2006)  

NASA Astrophysics Data System (ADS)

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).

Karatas, Y.; Schuster, W. J.

2007-05-01

243

VizieR Online Data Catalog: [Fe/H] & VMAG calibrations for UBV photometry (Karatas+, 2006)  

NASA Astrophysics Data System (ADS)

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).

Karatas, Y.; Schuster, W. J.

2007-05-01

244

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

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

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

245

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 Central

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

Reyes, Kristina; Gonzalez, Nicolas I.; Stewart, Joshua; Ospino, Frank; Nguyen, Dickie; Cho, David T.; Ghahremani, Nahal; Spear, John R.

2013-01-01

246

Extreme Ultraviolet Explorer Photometry of RS Canum Venaticorum Systems: Four Flaring Megaseconds  

NASA Astrophysics Data System (ADS)

We present an analysis of 12.2 Ms of Extreme Ultraviolet Explorer (EUVE) photometry of 16 RS CVn systems (including four flaring megaseconds). Our study attempts a systematic categorization of stellar coronal emission in RS CVn binary systems. The temporal resolution of the EUVE satellite and the opportunity for long observations enables us to study separately the quiescent and flaring states of RS CVn systems. Thirty of 31 observations are statistically variable. We examine light curves, characterizing both phase-dependent variations and large- and small-scale flaring. There is evidence for small-scale stochastic variability on the one short-period (Porb<1 day) system in our sample (ER Vul), which we interpret as small-scale flaring. CF Tuc is the only system for which phase-dependent variations over multiple orbital periods are seen. We analyze 30 flares on nine systems, fitting rise and decay times. Several flares have durations >0.5Porb and thus cannot originate from compact emission regions close to the stellar surfaces. Many flares have unusual flare morphologies, with rise times comparable to or greater than the decay time, and emission plateaus. In addition, eight flares have decay phases that are fit better by a broken power law than a single power law. The decay times for the second power law are statistically different than the single decay times and are correlated with the flare rise times. This observed connection points to the potential importance of the change in decay rate as a means of examining the physical processes operating during the flare. The distribution of orbital phases of flare onsets on V711 Tau (HR 1099), the best-studied RS CVn in our sample, is consistent with a Poisson distribution that is random in time. In two systems that are partially eclipsing (CF Tuc and ER Vul), we find no evidence for an eclipse in the light curve, indicating that the emission region is large compared to the stellar radius. We parameterize the distribution of flare energies as a power law, finding a cut-off energy of ~1033 ergs and a slope of -0.6. Flare energy increases with flare duration as E~?t1.42, confirming the long-duration nature of high-energy flares on RS CVn systems. The integrated flare luminosity depends on the quiescent luminosity as Lflare~L1.05quiescent. Flare frequencies range from 0.1 day-1 to 1.5 day-1. For observations not affected by the dead spot on the Deep Survey detector, 40% of the observed time was spent in a flaring state, indicating that flaring is a ``normal'' state for the coronae of these systems. We note the presence of a quasi-periodicity in EUVE photometric data on the order of 1 day, which is not corrected for in the standard reduction and analysis software.

Osten, Rachel A.; Brown, Alexander

1999-04-01

247

Feasibility of spectro-photometry in X-rays (SPHINX) from the moon  

NASA Astrophysics Data System (ADS)

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.

Sarkar, Ritabrata; Chakrabarti, Sandip Kumar

2010-08-01

248

Astrometry and Photometry of Binary Exoplanet Host Stars  

NASA Astrophysics Data System (ADS)

Using the adaptive optics system on the AEOS 3.6m telescope, we conducted an astrometry survey of stars hosting exo-planets discovered by radial velocity studies. The data were collected in I-band and multiple frames were collected and co-added to produce images capable of revealing faint stellar companions. The survey was intended to detect both optical and physical companions. Duplicity among exoplanet host stars can influence the planetary orbits. A census of faint background stars is important for coronagraphic imaging surveys, as it eliminates the possibility of mistagging a background star as a possible planetary companion. We present astrometry and photometry on 7 previously known binaries and for 8 newly detected companions. An additional 46 stars were observed with no signs of companions, We also present orbits for two of the previously known binaries: HIP 14954 (HD 19994 = HJ 663) and HIP 67275 (HD 120136 = STT 270).

ten Brummelaar, Theo; Turner, N. H.; Roberts, L. C., Jr.; Hartkopf, W. I.; Mason, B. D.

2009-12-01

249

The symbiosis of photometry and radial-velocity measurements  

NASA Technical Reports Server (NTRS)

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.

Cochran, William D.

1994-01-01

250

USING PHOTOMETRY TO PROBE THE CIRCUMSTELLAR ENVIRONMENT OF {delta} SCORPII  

SciTech Connect

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.

Jones, C. E.; Wiegert, P. A.; Cyr, R. P.; Halonen, R. J. [Department of Physics and Astronomy, Western University, London, ON N6A 3K7 (Canada); Tycner, C. [Department of Physics, Central Michigan University, Mt. Pleasant, MI 48859 (United States); Henry, G. W.; Muterspaugh, M. W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box No 9501, Nashville, TN 37209 (United States)

2013-05-15

251

Photometry and Spectroscopy with the SMARTS Consortium Telescopes  

NASA Astrophysics Data System (ADS)

We present recent results from the SMARTS Consortium Telescopes located at Cerro Tololo, designed to highlight the capabilities of the telescopes and instruments. We will report astrometry from the 0.9m+2KCCD obtained for the RECONS project (Dieterich et al. 2014 and Riedel et al. 2014), optical/IR photometry obtained with the 1.3m+ANDICAM for studies of X-ray binaries (e.g. MacDonald et al. 2014) and the SMARTS/Fermi blazar project (Bonning et al. 2012), and high-resolution spectroscopy obtained with the 1.5m+Chiron for exoplanet studies (Tokovinin et al. 2013). We note that time is available to new private partners on all these telescope/instrument combinations.

Bailyn, Charles D.; Buxton, Michelle; Misenti, Victoria; Fischer, Debra; Henry, Todd J.; Van Der Bliek, Nicole S.

2014-06-01

252

Broadband Photometry of the Potentially Hazardous Asteroid 2010 GU21  

NASA Astrophysics Data System (ADS)

The Near-Earth Asteroid (NEA) 2010 GU21 was discovered by the Catalina Sky Survey on April 5 2010 (MPEC 2010-G55) and has been designated as a Potentially Hazardous Asteroid (PHA) by the Minor Planet Center. We obtained Bessel BVRI photometry over the course of three nights at the JPL Table Mountain 0.6-m telescope (TMO), as illustrated in [1][2][3] and summarized in Table 1.

Hicks, M.; Somers, J.; Foster, J.; McAuley, A.

2010-04-01

253

Infrared spectral reflectances of asteroid surfaces  

NASA Technical Reports Server (NTRS)

This review compares the types of compositional information produced by three complementary techniques used in infrared observations of asteroid surfaces: broadband JHKL photometry, narrow band photometry, and multiplex spectroscopy. The high information content of these infrared observations permits definitive interpretations of asteroid surface compositions in terms of the major meteoritic minerals (olivine, pyroxene, plagioclase feldspar, hydrous silicates, and metallic Ni-Fe). These studies emphasize the individuality of asteroid surface compositions, the inadequacy of simple comparisons with spectra of meteorites, and the need to coordinate spectral measurements of all types to optimize diagnostic capabilities.

Larson, H. P.; Veeder, G. J.

1979-01-01

254

EXTENDED PHOTOMETRY FOR THE DEEP2 GALAXY REDSHIFT SURVEY: A TESTBED FOR PHOTOMETRIC REDSHIFT EXPERIMENTS  

SciTech Connect

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.

Matthews, Daniel J.; Newman, Jeffrey A. [Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, PA 15260 (United States); Coil, Alison L. [Department of Physics, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (United States); Cooper, Michael C. [Center for Galaxy Evolution, Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697 (United States); Gwyn, Stephen D. J., E-mail: djm70@pitt.edu, E-mail: janewman@pitt.edu, E-mail: acoil@ucsd.edu, E-mail: m.cooper@uci.edu, E-mail: Stephen.Gwyn@nrc-cnrc.gc.ca [Canadian Astronomical Data Centre, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, British Columbia V9E 2E7 (Canada)

2013-02-15

255

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)

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.

Boshar, John

1947-01-01

256

Steric factors affecting the discrimination of isomeric and structurally related olefin gases and vapors with a reagent-coated surface acoustic wave sensor.  

PubMed

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

Zellers, E T; Zhang, G Z

1992-06-01

257

Affective Domain  

NSDL National Science Digital Library

The affective domain can significantly enhance, inhibit or even prevent student learning. The affective domain includes factors such as student motivation, attitudes, perceptions and values. Teachers can increase their effectiveness by considering the affective domain in planning courses, delivering lectures and activities, and assessing student learning. This module contains information and resources for incorporating the affective domain into teaching.

258

The AAVSO Photoelectric Photometry Program in Its Scientific and Socio-Historic Context  

NASA Astrophysics Data System (ADS)

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.

Percy, J. R.

2012-06-01

259

Optical Photometry of BY Cam Modeled Using a Multipolar Magnetic Field Structure  

NASA Astrophysics Data System (ADS)

We present new high-speed broad-band optical photometry of the asynchronous polar (magnetic cataclysmic variable) BY Cam. Observations were obtained at the 2.1-m Otto Struve Telescope of McDonald observatory with 3s integration times. In an attempt to understand the complex changes in accretion flow geometry, we performed full 3D MHD simulations assuming a variety of white dwarf magnetic field structures including both aligned and non-aligned dipole plus quadrupole field components. We compare model predictions with photometry and various phases of the beat cycle and find that synthetic light curves derived from a multipolar field structure are consistent with the optical photometry.

Morales, John; Mason, P. A.; Zhilkin, A.; Bisikalo, D. V.; Robinson, E. L.

2014-01-01

260

THE ARAUCARIA PROJECT. A DISTANCE DETERMINATION TO THE LOCAL GROUP SPIRAL M33 FROM NEAR-INFRARED PHOTOMETRY OF CEPHEID VARIABLES  

SciTech Connect

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.

Gieren, Wolfgang; Pietrzynski, Grzegorz; Graczyk, Dariusz, E-mail: wgieren@astro-udec.cl, E-mail: pietrzyn@hubble.cfm.udec.cl [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warsaw (Poland); and others

2013-08-10

261

3.6-7.9 um Photometry of L and T Dwarfs and the Prevalence of Vertical Mixing in their Atmospheres  

E-print Network

We present new L' (3.75 um) photometry of six L and T dwarfs, and M' (4.70 um) photometry of ten L and T dwarfs, observed at Gemini Observatory, and new 3.55, 4.49, 5.73 and 7.87 um photometry of nine L and T dwarfs, obtained with the Spitzer Space Telescope. The sample includes unusually blue and red dwarfs from our near-infrared studies. The data are combined with published L', M' and Spitzer photometry of L and T dwarfs, and trends of colors with spectral type and other colors are examined. Model atmospheres by Marley and Saumon are used to generate synthetic colors for ranges of effective temperature, gravity, grain sedimentation efficiency, metallicity and vertical mixing efficiency. We explore how these parameters affect the mid-infrared colors of L and T dwarfs and find that the data are modelled satisfactorily only if substantial vertical mixing occurs in both L- and T-dwarf atmospheres. The location and range of the L and T dwarf sequences in IRAC color-color and color - magnitude diagrams is also only reproduced if this mixing occurs, with a range of efficiency described by K_zz ~ 10^2-10^6 cm^2/s. The colors of the unusually red dwarfs are best reproduced by non-equilibrium models with low sedimentation efficiency, i.e. thick cloud decks, and those of the unusually blue dwarfs by non-equilibrium models with high sedimentation efficiency, i.e. thin cloud decks. The K-L' and Spitzer [3.55]-[4.49] colors can be used as indicators of effective temperature for L and T dwarfs, but care must be taken to include gravity and metallicity effects for late-T dwarfs and vertical mixing for both late-L and T dwarfs.

S. K. Leggett; D. Saumon; M. S. Marley; T. R. Geballe; D. A. Golimowski; D. Stephens; X. Fan

2006-10-06

262

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)

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.

Weiss, Dominik; Salaun, Pascal; Van den Berg, Stan; Bi, Zaoshun

2014-05-01

263

Photometry and Spectroscopy of BD+35 1111 in M38  

NASA Astrophysics Data System (ADS)

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 H? 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.

Souza, Steven P.; Kwitter, Karen B.; Sami, Mona; Beltz-Mohrmann, Gillian

2014-06-01

264

Improved LRG Selection Algorithms combining Optical And WISE (Infrared) Photometry  

NASA Astrophysics Data System (ADS)

Luminous red galaxies (LRGs) are the most massive galaxies in nearby universe of z < 1.0 which appear to have formed the bulk of their stars at early times. Mostly ellipticals, they are associated with massive dark matter halos and hence cluster very strongly which makes them an excellent tracer of the large-scale structure of the Universe. LRGs at z < 0.6 can be selected efficiently using optical photometry, but at z >0.6 this becomes increasingly difficult. Here we present the results of new techniques now being applied to select LRGs at redshifts 0.6 < z < 1 utilizing SDSS and WISE photometry in combination. Old stellar populations exhibit a global maximum in their SED at a wavelength of 1.6 ?m, commonly referred to as the '1.6 ?m bump'. Since LRGs possess very few young stars, this feature generally dominates their overall spectral energy distribution. The lowest wavelength channel in WISE is centered at 3.4 ?m, causing LRGs that are at 1 to be extremely bright in this band compared to the optical. As a result, the r-W1 vs. r-i color-color diagram (where W1 is the 3.4 ?m WISE AB magnitude) provides an efficient tool for selecting high-redshift LRGs while avoiding stars. In this poster, we present new results from efforts to optimize the color cut used to select LRGs, yielding samples with a very low stellar contamination rate, but a high fraction of galaxies that are both at z>0.6 and intrinsically red in color. Studying their properties and distribution can also help us determine the mechanisms by which these rare objects form. We have tested this method using photometric redshifts and spectroscopic redshifts in the COSMOS field and DEEP2 fields respectively. LRGs selected with this method are the targets for future-generation surveys such as eBOSS and DESI and undergoing surveys like, SEQUELS BOSS ancillary survey which aim at high precision measurement of BAO.

Prakash, Abhishek; Newman, J.; eBOSS Collaboration

2014-01-01

265

Photometry of Be Stars in the vicinity of COROT primary targets for asteroseismology  

E-print Network

We present differential photometry of Be stars close to potential COROT primary targets for asteroseismology. Several stars are found to be short period variables. We propose them to be considered as secondary targets in the COROT asteroseismology fields.

J. Gutierrez-Soto; J. Fabregat; J. Suso; A. M. Hubert; M. Floquet; R. Garrido

2003-09-29

266

Determination of the Components of Reagent and Buffer Solutions by Flame Photometry.  

National Technical Information Service (NTIS)

An analytical process has been worked out for quantitative determination by flame photometry of sodium-potassium tartrate in a Fehling II and Nylander solution, potassium dehydrophosphate, and sodium monohydrophosphate in buffer phosphate solutions used r...

M. Sarsunova, S. Szuesova

1971-01-01

267

Precision of a Low-Cost InGaAs Detector for Near Infrared Photometry  

E-print Network

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. ...

Simcoe, Robert A.

268

Photometry of infrared space telescope images using the grid PRF method Dphot  

NASA Astrophysics Data System (ADS)

The grid PRF photometry method Dphot detects and measures point sources and extended sources using the Basic Calibrated Data images from the Spitzer Space Telescope without prior source position information. A mosaic is not used. Point sources with separations as small as 1.0 arcsec can be detected and measured. Examples of Dphot photometry are presented for 47 Tuc, the Galactic Center, Einstein Cross, and galaxies in GOODS North.

Elliott, David G.

2012-09-01

269

On the benefits of photometry for roAp theory: MOST observations of ? Equulei (HD 201601)  

NASA Astrophysics Data System (ADS)

We discuss the potential of space photometry for rapidly oscillating Ap (roAp) stars. In reference to the MOST observations of ?Equulei (Gruberbauer et al., 2008), we show that several aspects of the roAp phenomenon demand longer observational time bases and better time sampling than those currently feasible using spectroscopy. We conclude that, in order to improve our understanding of roAp stars, photometry is still an important tool which should not be neglected.

Gruberbauer, M.; Weiss, W. W.

2008-04-01

270

UBVRI and Halpha Photometry of the Young Open Cluster NGC 6530  

Microsoft Academic Search

New UBVRI and Halpha photometry has been obtained for the young open cluster NGC 6530 located 10' east of the Lagoon Nebula (M8). We found 37 pre-main-sequence (PMS) stars with Halpha emission and nine PMS candidates using the R-Halpha color, a measure of Halpha emission. From this new photometry we derived the cluster parameters (V0-MV=11.25+\\/-0.1 mag and =0.35 mag), typical

Hwankyung Sung; Moo-Young Chun; Michael S. Bessell

2000-01-01

271

VizieR Online Data Catalog: WASP-104b and WASP-106b photometry (Smith+, 2014)  

NASA Astrophysics Data System (ADS)

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).

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

272

UBVRI H(alpha) Photometry of the Young Open Cluster NGC 2264  

NASA Astrophysics Data System (ADS)

UBVRI H? CCD photometry has been obtained for the young open cluster NGC 2264. Using (R -H?) color, a measure of H? emission, we selected member stars in the pre-main-sequence (PMS) stage. The reliability of the (R -H?) color as a PMS star selection criterion was critically evaluated from their spatial distribution, near-IR photometric data and spectroscopic characteristics. By constructing the HR diagram, we determined the typical age and age spread of NGC 2264. Some discussions on the age discrepancy between turn-off age and turn-on age in a cluster were made. The shape of the initial mass function (IMF) of NGC 2264 is very similar to that of the Orion Nebula Cluster, but the surface density is far lower than that of NGC 6231 or the Orion Nebula Cluster. By assuming that the thickness (or amount of mass) of the circumstellar shell is linearly proportional to the strength of the H? emission ? (R - H?) (? (R -H?)* - ( R - H?)MS), it can be concluded that the amount of material in the circumstellar shell is not the main source of spread in magnitude due to the lack of correlation between ?(R - H?) and ?Mv (?Mv*-MtV=2 Myr).

Sung, Hwangkyung; Bessell, Michael S.; Lee, See-Woo

1997-12-01

273

DDO Photometry of M71: Carbon and Nitrogen Patterns Among Evolving Giants  

E-print Network

We present V, B-V, and DDO C(41-42) and C(42-45) photometry for a sample of 75 red giants down to M_V = +2 in the relatively metal-rich Galactic globular cluster M71. The C(41-42) colors reveal a bimodal distribution of CN band strengths generally anticorrelated with CH band strength as measured by the C(42-45) color. Both DDO colors agree well with those found in 47 Tucanae -- a nearby globular cluster of similar metallicity -- and suggest nearly identical C and N abundance patterns among the giants of both clusters. A comparison with synthetic DDO colors demonstrates that little change in surface C or N abundance is required to match the colors of the M71 giants over the entire luminosity range observed. Apparently like 47 Tuc (a cluster of much greater mass and central concentration), M71 exhibits an abundance pattern which cannot be solely the result of internal mixing.

M. M. Briley; G. H. Smith; C. F. Claver

2001-08-07

274

Star clusters in M33: updated UBVRI photometry, ages, metallicities, and masses  

E-print Network

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$^2$ 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 {\\sc parsec} simple stellar populations synthesis models. The results of our $\\chi^2$ minimization routines show that only 205 o...

Fan, Zhou

2014-01-01

275

Transit Timing Variations as an Exercise for High Precision Photometry  

NASA Astrophysics Data System (ADS)

Extrasolar planet transit timing variations (TTVs) provide an excellent means of professional/amateur collaboration that can also serve as a good test-project to assess an effort to improve a research telescope's photometry performance. I started a global telescope TTV project to look for perturbations in the timing of transits of known extrasolar planets as a project to "work out” the newly acquired telescopes. These perturbations can indicate the presence of unknown additional planets that if under favorable resonance conditions can reveal planets with a mass as low as an earth mass. TTV observations also do double by how the light curves provides an opportunity to do detailed study of the planet and star's effects on the light curve. For these purposed I arranged a collaboration to use the FTN telescope on Maui, Hawaii, and we joined the larger Transit Light Curve (TLC) project. I was stationed near FTN in Maui, Hawaii to do a year-long effort to commission the 2.0m FTN, using such test projects. Results that are available a year after this project started will be presented. Professional/amateur collaborations are particularly essential to this project especially in the event that the original telescope data fails to be released. Expected accomplishments of achieving the full data will be presented.

Taylor, Stuart F.

2009-01-01

276

Analysis of RGU Photometry in Selected Area 51  

E-print Network

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 colour-magnitude diagrams. The unusually large scattering in the two-colour 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. (1993). The local logarithmic space density for giants, D(0)=6.75, lies within the local densities of Gliese (1969) and Gliese & Jahreiss (1992). The local luminosity function for the absolute magnitude interval 3

S. Bilir; S. Karaali; R. Buser

2004-07-02

277

Glory revealed in disk-integrated photometry of Venus  

E-print Network

Context. Reflected light from a spatially unresolved planet yields unique insight into the overall optical properties of the planet cover. Glories are optical phenomena caused by light that is backscattered within spherical droplets following a narrow distribution of sizes; they are well known on Earth as localised features above liquid clouds. Aims. Here we report the first evidence for a glory in the disk-integrated photometry of Venus and, in turn, of any planet. Methods. We used previously published phase curves of the planet that were reproduced over the full range of phase angles with model predictions based on a realistic description of the Venus atmosphere. We assumed that the optical properties of the planet as a whole can be described by a uniform and stable cloud cover, an assumption that agrees well with observational evidence. Results. We specifically show that the measured phase curves mimic the scattering properties of the Venus upper-cloud micron-sized aerosols, also at the small phase angles ...

Muñoz, A García; Sánchez-Lavega, A

2014-01-01

278

Infrared imaging and photometry of Comet Giacobini-Zinner  

NASA Astrophysics Data System (ADS)

Infrared images and photometry were obtained to determine the spatial distribution and physical characteristics (temperature, albedo, size distribution, total mass, etc.) of the grains in the coma of Comet GZ. A 10.8 m image of Comet GZ obtained on August 4 represents the first groundbased thermal-infrared image of a Comet. Among the most significant results are: (1)An estimate of the number of grains that the ICE spacecraft must have encountered, which led the plasma wave team to conclude that they could only detect impacts on the antennae and not on the whole body of the ICE spacecraft; (2)The discovery of a population of large grains (radius > 100 micrometer), not observed in most other comets, which formed a curved tail near the nucleus (within 80 arcsec or 34,000 km); and (3)the detection of structure in the spatial distribution in the coma of the particle albedo, which was tentatively attributed to the presence of very fluffy grains which are likely to have multiple internal scattering of incident sunlight. The albedo map of Comet GZ was obtained by combining the 10.8 micrometer image shown with a simultaneous image taken at 0.68 micrometer, a bandpass which isolates the scattered continuum.

Campins, H.

1986-09-01

279

Small Telescope Infrared Photometry of the epsilon Aurigae Eclipse  

NASA Astrophysics Data System (ADS)

Near-infrared photometry of epsilon Aurigae, in the H- and J-bands, was undertaken during the 2009-2011 eclipse using telescopes of moderate size (8-inch and 14-inch diameter). Instruments of this size successfully collected scientific data in the H- and J-bands. Observations were made from the campus of East Tennessee State University (ETSU), Johnson City, Tennessee, the campus of King College, Bristol, Tennessee, and from the author's home. Signal/Noise ratios of approximately 45 were obtained during times of maximum eclipse. Higher S/N ratios could have been obtained by extending the length of time on target. S/N ratios of almost 100 were obtained outside of eclipse. The infrared light curves produced closely parallel the light curve in the visual range (V), being about 0.5 magnitude brighter in H and 0.7 magnitude brighter in J. The eclipse was easily detected and followed throughout its duration. The rate of ingress was shallower than the rate of egress in both the H- and J-bands. The background variations of the primary star were readily detected.

Rutherford, T. P.

2012-06-01

280

RELATIVE PHOTOMETRY OF HAT-P-1b OCCULTATIONS  

SciTech Connect

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.

Beky, Bence; Holman, Matthew J.; Noyes, Robert W.; Sasselov, Dimitar D. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138 (United States); Gilliland, Ronald L. [Center for Exoplanets and Habitable Worlds, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Bakos, Gaspar A. [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544 (United States); Winn, Joshua N., E-mail: bbeky@cfa.harvard.edu [Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 70 Vassar Street, Cambridge, MA 02139 (United States)

2013-06-01

281

HUBBLE SPACE TELESCOPE PHOTOMETRY OF GLOBULAR CLUSTERS IN M81  

SciTech Connect

We perform aperture photometry and profile fitting on 419 globular cluster (GC) candidates with m{sub V} {<=} 23 mag identified in Hubble Space Telescope/Advanced Camera for Surveys BVI imaging, and estimate the effective radii of the clusters. We identify 85 previously known spectroscopically confirmed clusters, and newly identify 136 objects as good cluster candidates within the 3{sigma} color and size ranges defined by the spectroscopically confirmed clusters, yielding a total of 221 probable GCs. The luminosity function peak for the 221 probable GCs with estimated total dereddening applied is V {approx} (20.26 {+-} 0.13) mag, corresponding to a distance of {approx}3.7 {+-} 0.3 Mpc. The blue and red GC candidates, and the metal-rich and metal-poor spectroscopically confirmed clusters, respectively, are similar in half-light radius. Red confirmed clusters are about 6% larger in median half-light radius than blue confirmed clusters, and red and blue good GC candidates are nearly identical in half-light radius. The total population of confirmed and 'good' candidates shows an increase in half-light radius as a function of galactocentric distance.

Nantais, Julie B. [Departamento de Astronomia, Universidad de Concepcion Av. Esteban Iturra s/n Barrio Universitario Casilla 160-C Concepcion (Chile); Huchra, John P.; Zezas, Andreas; Gazeas, Kosmas; Strader, Jay [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2011-12-15

282

BRITE-Constellation: nanosatellites for precision photometry of bright stars  

E-print Network

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 degrees), so up to about 15 bright stars can be observed simultaneously, sampled in 32 pixel x 32 pixel 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 e...

Weiss, W W; 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; CCD,

2014-01-01

283

Distance to NGC 1569 via Deep HST/ACS Photometry  

NASA Astrophysics Data System (ADS)

The dwarf irregular galaxy NGC 1569 is the closest and strongest starburst galaxy to the Milky Way, and contains three of the most massive super star clusters ever discovered. Using the ACS/WFC on the Hubble Space Telescope we have obtained the deepest optical photometry of this galaxy to date, yielding a V,I color-magnitude diagram (CMD) with some 450,000 stars. These data have allowed us, for the first time, to unequivocally measure the brightness of the tip of the red giant branch and thereby determine the distance to NGC 1569. We find that this galaxy lies 40% farther away than what is typically assumed. The longer distance makes NGC 1569 an even more extreme starburst galaxy; previous estimates of the star formation shift to younger epochs and the rate of star formation becomes stronger by a factor of 2. In addition, with the new distance the dynamical masses of the super star clusters increase by 40% while their luminosities double. Preliminary results on the star formation history of NGC 1569 as inferred from the observed CMD will also be presented.

Grocholski, Aaron J.; Aloisi, A.; van der Marel, R. P.; Mack, J.; Annibali, F.; Sirianni, M.; Angeretti, L.; Romano, D.; Tosi, M.; Greggio, L.; Held, E. V.

2008-05-01

284

Performance of Electroluminescent Flats for Precision Light Curve Photometry  

NASA Astrophysics Data System (ADS)

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.

Avril, Ryan L.; Oberst, T. E.

2014-01-01

285

Campaign Photometry During The 2010 Eclipse Of Epsilon Aurigae  

NASA Astrophysics Data System (ADS)

Epsilon Aurigae is a long period (27.1 years) eclipsing binary star system with an eclipse that lasts nearly 2 years, but with severe ambiguities about component masses and shape. The current eclipse began on schedule in August of 2009. During the previous, 1982-1984 eclipse, an International Campaign was formed to coordinate a detailed study of the system. While that Campaign was deemed successful, the evolutionary status of the star system remained unclear. Epsilon Aurigae has been observed nearly continuously since the 1982 eclipse. The current Campaign was officially started in 2006. In addition to a Yahoo forum we have a dedicated web site and more than 18 online newsletters reporting photometry, spectroscopy, interferometry and polarimetry data. High quality UBVRIJH band photometric data since before the start of the current eclipse has been submitted. We explore the color differences among the light curves in terms of eclipse phases and archival data. At least one new model of the star system has been proposed since the current Campaign began: a low mass but very high luminosity F star plus a B star surrounded by a debris disk. The current eclipse and in particular the interferometry and spectroscopic data have caused new thoughts on defining eclipsing variable star contact points and phases of an eclipse. Second contact may not be the same point as start of totality and third contact may not be the same point as the start of egress and end of totality. In addition, the much awaited mid-eclipse brightening may or may not have appeared. This paper identifies the current Campaign contributors and the photometric data. This work was supported in part by the bequest of William Herschel Womble in support of astronomy at the University of Denver, by NSF grant 1016678 to the University of Denver.

Hopkins, Jeff; Stencel, R. E.

2011-01-01

286

Just the Photometry: Constraining exoplanet orbits by measuring stellar densities  

NASA Astrophysics Data System (ADS)

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.

Sliski, David; Kipping, D. M.

2014-01-01

287

Multicolor Photometry of the Type II Cepheid Prototype W Virginis  

NASA Astrophysics Data System (ADS)

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.

Templeton, M. R.; Henden, A. A.

2007-11-01

288

Open Cluster Survey: Time-Series Monitoring and Precise Photometry  

NASA Astrophysics Data System (ADS)

Star clusters, especially compact ones (with diameter of few to ten arcmin), are suitable targets to search for light variability in a group of stars by means of an ordinary Cassegrain telescope plus CCD system. A special patrolling with short time-fixed exposures and mmag accuracy could be used also to study stellar oscillation for a group of stars simultaneously. The last can be carried out both separately from one site and within the WET(Whole-Earth Telescope) XCov campaigns. The detection of extra-solar planet transit events might be a by-product of a long-term monitoring of compact open clusters as well. We present the program of open star clusters monitoring with the Zeiss 1 meter RCC telescope of Maidanak observatory which has been recently automated. In combination with quite good seeing at this observatory (see, e.g., Sarazin, M. 1999, URL http://www.eso.org/gen-fac/pubs/astclim/) the automatic telescope, equipped with a large-format (2KX2K) CCD camera AP-10, will allow collecting homogeneous time-series for analysis. We already started this program in 2001 and had a set of patrol observations with a Zeiss 0.6 meter telescope and an AP-10 camera in 2003. Seven compact open clusters in the Milky Way (NGC 7801, King 1, King 13, King 8, King 20, Berkeley 55, IC 4996) have been monitored for stellar variability and some results of photometry will be presented. A few interesting variables were discovered and dozens for the moment are suspected of variability for the first time within our program. It is also shown how observations like these could feasibly be used for exo-planet searches. We have made steps to join the Whole-Earth Telescope effort in future campaigns for Asteroseismology.

Hojaev, A. S.; Semakov, D. G.

2006-08-01

289

Precision Photometry to Study the Nature of Dark Energy  

SciTech Connect

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.

Lorenzon, Wolfgang; Schubnell, Michael

2011-01-30

290

Spitzer Photometry of WISE-selected Brown Dwarf and Hyper-luminous Infrared Galaxy Candidates  

NASA Astrophysics Data System (ADS)

We present Spitzer 3.6 and 4.5 ?m photometry and positions for a sample of 1510 brown dwarf candidates identified by the Wide-field Infrared Survey Explorer (WISE) all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12). Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify seven fainter (4.5 ?m ~ 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy candidates. For this control sample, we find another six brown dwarf candidates, suggesting that the seven companion candidates are not physically associated. In fact, only one of these seven Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this, there is no evidence for any widely separated (>20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of ~7.33 × 105 objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 ?m photometry, along with positionally matched B and R photometry from USNO-B; J, H, and Ks photometry from Two Micron All-Sky Survey; and W1, W2, W3, and W4 photometry from the WISE all-sky catalog.

Griffith, Roger L.; Kirkpatrick, J. Davy; Eisenhardt, Peter R. M.; Gelino, Christopher R.; Cushing, Michael C.; Benford, Dominic; Blain, Andrew; Bridge, Carrie R.; Cohen, Martin; Cutri, Roc M.; Donoso, Emilio; Jarrett, Thomas H.; Lonsdale, Carol; Mace, Gregory; Mainzer, A.; Marsh, Ken; Padgett, Deborah; Petty, Sara; Ressler, Michael E.; Skrutskie, Michael F.; Stanford, Spencer A.; Stern, Daniel; Tsai, Chao-Wei; Wright, Edward L.; Wu, Jingwen; Yan, Lin

2012-11-01

291

Shear Wave Velocity Profiles Determined from Surface Wave Measurements at Sites Affected by the August 15th, 2007 Earthquake in Peru  

Microsoft Academic Search

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

B. L. Rosenblad; J. A. Bay

2008-01-01

292

Adhesion of Streptococcus mitis and Actinomyces oris in co-culture to machined and anodized titanium surfaces as affected by atmosphere and pH  

PubMed Central

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

2013-01-01

293

Rotational Modulation and Flares on Rs-Canum and By-Draconis Stars - Part Seventeen - Ultraviolet Spectroscopy and Optical Photometry of Au-Microscopii in 1986  

NASA Astrophysics Data System (ADS)

We present IUE spectroscopy and optical photometry of the active late type star AU Mic. The UV spectroscopy allow us to measure the chromospheric and transition region line fluxes. No detectable variations attributable to rotational modulation were evident in either the chromospheric lines or optical bands. We have produced an emission measure curve for the quiescent state of AU Mic, which spans a temperature range 4.0 ? log Te ? 7.6 when coupled with previous X-ray flux measurements. The quiescent radiative losses per unit surface area over the above temperature range is ?8 1O7 erg cm-2 s-1

Quin, D. A.; Doyle, J. G.; Butler, C. J.; Byrne, P. B.; Swank, J. H.

1993-05-01

294

Surface adsorption, intracellular accumulation and compartmentalization of Pb(II) in batch-operated lagoons with Salvinia minima as affected by environmental conditions, EDTA and nutrients  

Microsoft Academic Search

The effects of environmental factors and nutrients on the various possible removal mechanisms (surface adsorption, intracellular\\u000a accumulation and precipitation to sediments) and partitioning of lead among various compartments (plant biomass, water column\\u000a and sediments) in Salvinia minima batch-operated lagoons, were evaluated. Surface adsorption was found to be the predominant mechanism for Pb(II) removal under\\u000a all environmental conditions tested in the

Eugenia J. Olguín; Gloria Sánchez-Galván; Teresa Pérez-Pérez; Arith Pérez-Orozco

2005-01-01

295

High-precision ground-based photometry of exoplanets  

NASA Astrophysics Data System (ADS)

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.

de Mooij, Ernst J. W.; Jayawardhana, Ray

2013-04-01

296

a necessary consequence of Titan's widely varying seasonal insola-tion, will affect the magnitude of the surface sensible heat flux  

E-print Network

a necessary consequence of Titan's widely varying seasonal insola- tion, will affect the magnitude lapse rate is close to the boundary between stability and instability, as has been measured on Titan13 will not occur. At the time of our observations, Titan was approaching southern summer solstice, and, owing

Cai, Long

297

The Panchromatic Hubble Andromeda Treasury X. Ultraviolet to Infrared Photometry of 117 Million Equidistant Stars  

E-print Network

We have measured stellar photometry with the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS) 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 (PHAT) survey, we measured photometry with simultaneous point spread function fitting across all bands and at all source positions after precise astrometric image alignment (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. We pres...

Williams, Benjamin F; Dalcanton, Julianne J; Dolphin, Andrew E; Weisz, Daniel R; Bell, Eric F; Bianchi, Luciana; Byler, Eleanor; Gilbert, Karoline M; Girardi, Leo; Gordon, Karl; Gregersen, Dylan; Johnson, L C; Kalirai, Jason; Lauer, Tod R; Monachesi, Antonela; Rosenfield, Philip; Seth, Anil; Skillman, Evan

2014-01-01

298

Reference-less detection, astrometry, and photometry of faint companions with adaptive optics  

E-print Network

We propose a complete framework for the detection, astrometry, and photometry of faint companions from a sequence of adaptive optics corrected short exposures. The algorithms exploit the difference in statistics between the on-axis and off-axis intensity. Using moderate-Strehl ratio data obtained with the natural guide star adaptive optics system on the Lick Observatory's 3-m Shane Telescope, we compare these methods to the standard approach of PSF fitting. We give detection limits for the Lick system, as well as a first guide to expected accuracy of differential photometry and astrometry with the new techniques. The proposed approach to detection offers a new way of determining dynamic range, while the new algorithms for differential photometry and astrometry yield accurate results for very faint and close-in companions where PSF fitting fails. All three proposed algorithms are self-calibrating, i.e. they do not require observation of a calibration star thus improving the observing efficiency.

Szymon Gladysz; Julian C. Christou

2008-05-13

299

Optical BVRI Photometry of Common Proper Motion F/G/K+M Wide Separation Binaries  

NASA Astrophysics Data System (ADS)

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.

Li, Ting; Marshall, Jennifer L.; Lépine, Sébastien; Williams, Patrick; Chavez, Joy

2014-10-01

300

Time-series BVI Photometry for the Globular Cluster NGC 6981  

NASA Astrophysics Data System (ADS)

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. This paper makes use of data obtained from the Isaac Newton Group Archive, which is maintained as part of the CASU Astronomical Data Centre at the Institute of Astronomy, Cambridge.

Amigo, P.; Stetson, P. B.; Catelan, M.; Zoccali, M.; Smith, H. A.

2013-11-01

301

TIME-SERIES BVI PHOTOMETRY FOR THE GLOBULAR CLUSTER NGC 6981 {sup ,} {sup ,}  

SciTech Connect

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.

Amigo, P.; Catelan, M.; Zoccali, M. [Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago (Chile); Stetson, P. B. [Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Smith, H. A., E-mail: mcatelan@astro.puc.cl, E-mail: mzoccali@astro.puc.cl, E-mail: pia.amigo@dfa.uv.cl, E-mail: Peter.Stetson@nrc-cnrc.gc.ca, E-mail: smith@pa.msu.edu [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

2013-11-01

302

Precision of a Low-Cost InGaAs Detector for Near Infrared Photometry  

NASA Astrophysics Data System (ADS)

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.

Sullivan, Peter W.; Croll, Bryce; Simcoe, Robert A.

2013-09-01

303

Star Clusters in M33: Updated UBVRI Photometry, Ages, Metallicities, and Masses  

NASA Astrophysics Data System (ADS)

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 ?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 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.

Fan, Zhou; de Grijs, Richard

2014-04-01

304

Surface-wave site characterization at 53 strong-motion recording stations affected by the Parkfield, California, M6.0 earthquake of 28 September 2004  

USGS Publications Warehouse

We present one-dimensional shear-wave velocity (VS) profiles at 52 strong-motion sites that recorded the 28 September 2004 Magnitude 6.0 Parkfield, Calif., earthquake. We estimate the VS profiles with the Spectral Analysis of Surface-Waves (SASW) method. The SASW method is a noninvasive method that indirectly estimates the VS at depth from variations in the Rayleigh wave phase velocity at the surface. To address the uncertainty associated with these measurements, we compare the SASW profiles to surface-source downhole-receiver (SSDR) profiles at four sites. Three of the four SSDR sites are in close agreement with the adjacent SASW site, while the SASW profile is considerably slower than the SSDR profile at one site.

Thompson, Eric M.; Kayen, Robert E.; Carkin, Brad; Tanaka, Hajime

2010-01-01

305

Optical photometry of the eclipsing Large Magellanic Cloud supersoft source CAL 87  

E-print Network

We present optical photometry of the eclipsing supersoft source, CAL87. These observations comprise long term data accumulated as a by-product of the MACHO Project, and high speed white light photometry of a single eclipse. We (i) derive an improved ephemeris of To = HJD 2450111.5144(3) + 0.44267714(6)E for the time of minimum light, (ii) find the eclipse structure to be stable over a period of 4 years, and (iii) investigate the colour variation as a function of orbital phase. The resolution afforded by the high speed nature of the white light observations enables us to see new structure in the light curve morphology.

C. Alcock

1997-02-13

306

CHEOPS: a space telescope for ultra-high precision photometry of exoplanet transits  

NASA Astrophysics Data System (ADS)

The CHaracterising ExOPlanet Satellite (CHEOPS) is a joint ESA-Switzerland space mission (expected to launch in 2017) dedicated to search for exoplanet transits by means of ultra-high precision photometry. CHEOPS will provide accurate radii for planets down to Earth size. Targets will mainly come from radial velocity surveys. The CHEOPS instrument is an optical space telescope of 30 cm clear aperture with a single focal plane CCD detector. The tube assembly is passively cooled and thermally controlled to support high precision, low noise photometry. The telescope feeds a re-imaging optic, which supports the straylight suppression concept to achieve the required Signal to Noise.

Fortier, Andrea; Beck, Thomas; Benz, Willy; Broeg, Christopher; Cessa, Virginie; Ehrenreich, David; Thomas, Nicolas

2014-08-01

307

High-Quality Photometry of Asteroids at Millimeter and Submillimeter Wavelengths  

NASA Astrophysics Data System (ADS)

Photometric observations with the JCMT at millimeter and submillimeter wavelengths have been made for the asteroids 1 Ceres, 4 Vesta, 6 Hebe, 7 Iris, 16 Psyche, 18 Melpomene, and 216 Kleopatra. The measurements reported here include a careful estimation of the possible systematic biases that may be present in the photometry. Whenever possible, the flux densities have been averaged over a complete rotational light curve to eliminate rotational phase as a source of uncertainty. Combining our measurements with those from the literature at other wavelengths, we present spectral energy distributions (SEDs) for the thermal emission from these asteroids spanning the infrared and radio ranges. The effective emissivity e_EFF is defined as the ratio of the observed flux density to that which would have been observed from a nonrotating, spherical blackbody with the same size, distance from the Earth, and distance from the Sun, as though viewed at opposition. The physical properties that influence e_EFF are discussed qualitatively, using our SEDs to illustrate the importance of each effect. In this way, the effective emissivity is demonstrated to be a useful means to present the SED of an asteroid over the whole range of wavelengths for which thermal emission dominates the observable flux density. The most important physical properties that distinguish the SEDs of the nonmetallic asteroids (Ceres, Vesta, Hebe, Iris, and Melpomene) from each other appear to be (1) the optical depth through the layer of warm material that has been heated by the Sun on the day side of the asteroid; (2) the density of the surface materials; and (3) the rotation period of the asteroid. For Ceres the warm surface layer is partially opaque at wavelengths near 1 mm, while for Vesta it is transparent at all wavelengths longer than 0.35 mm. We attribute the transparency of Vesta's warm surface layer to its low density. In contrast, Iris appears to have relatively dense materials on its surface that transport heat effectively from its surface to its deeper layers, reducing the infrared beaming compared to Ceres and increasing the optical depth of its warm surface layer compared to Vesta. The effectiveness of rotation in suppressing the infrared beaming phenomenon is illustrated by Vesta, a rapid rotator with a weak infrared beaming effect, and by Melpomene, a slow rotator with a strong infrared beaming effect. The SEDs of the M-type (metallic) asteroids (Psyche and Kleopatra) have a distinctive shape, with a steep decrease from infrared to radio wavelengths. The effective emissivities at wavelengths near 1 mm are too low to correspond to physical temperatures in the asteroids' surfaces but are consistent with the presence of large metal fractions in their surface minerals, which would make their surfaces reflective rather than emissive at long wavelengths. This is the first clear mineralogical distinction that we have been able to make based on the shape of an asteroid's SED.

Redman, Russell O.; Feldman, P. A.; Matthews, H. E.

1998-09-01

308

VAPHOT -A Package for Precision Differential Aperture Photometry HANS J. DEEG1,2, LAURANCE R. DOYLE3  

E-print Network

to perform reliable and precise time-series photometry of uncrowded fields. This package works within the IRAF environment and is built upon the standard aperture photometry task `phot' from IRAF. The design is outlined; the calculation of these sizes is performed by a subroutine `apcalc' within the `vaphot' package

Deeg, Hans-Jörg

309

Deletion of the Hoc and Soc capsid proteins affects the surface and cellular uptake properties of bacteriophage T4 derived nanoparticles  

PubMed Central

Recently the use of engineered viral scaffolds in biotechnology and medical applications has been increasing dramatically. T4 phage capsid derived nanoparticles (NPs) have potential advantages as sensors and in biotechnology. These applications require that the physical properties and cellular uptake of these NPs be understood. In this study we used a T4 deletion mutant to investigate the effects of removing both the Hoc and Soc proteins from the capsid surface on T4 tailless NPs. The surface charge, zeta potential, size, and cellular uptake efficiencies for both the T4 NP and T4?Hoc?Soc NP mutant were measured and compared using dynamic light scattering and flow cytometry and significant differences were detected. PMID:22285187

Robertson, Kelly; Furukawa, Yoko; Underwood, Alison; Black, Lindsay; Liu, Jinny L.

2014-01-01

310

Deletion of the Hoc and Soc capsid proteins affects the surface and cellular uptake properties of bacteriophage T4 derived nanoparticles.  

PubMed

Recently the use of engineered viral scaffolds in biotechnology and medical applications has been increasing dramatically. T4 phage capsid derived nanoparticles (NPs) have potential advantages as sensors and in biotechnology. These applications require that the physical properties and cellular uptake of these NPs be understood. In this study we used a T4 deletion mutant to investigate the effects of removing both the Hoc and Soc proteins from the capsid surface on T4 tailless NPs. The surface charge, zeta potential, size, and cellular uptake efficiencies for both the T4 NP and T4?Hoc?Soc NP mutant were measured and compared using dynamic light scattering and flow cytometry and significant differences were detected. PMID:22285187

Robertson, Kelly; Furukawa, Yoko; Underwood, Alison; Black, Lindsay; Liu, Jinny L

2012-02-17

311

Effect of sampling method on contaminant measurement in pore-water and surface water at two uranium operations: can method affect conclusions?  

Microsoft Academic Search

This paper describes a comparison of two methods of sediment pore-water sampling and two methods of surface water sampling\\u000a that were used in a broader investigation of cause(s) of adverse effects on benthic invertebrate communities at two Saskatchewan\\u000a uranium operations (Key Lake and Rabbit Lake). Variables measured and compared included pH, ammonia, DOC, and trace metals.\\u000a The two types of

Erin L. Robertson; Karsten Liber

2009-01-01

312

Geochemical distribution and removal of As, Fe, Mn and Al in a surface water system affected by acid mine drainage at a coalfield in Southwestern China  

NASA Astrophysics Data System (ADS)

The chemical characteristics, formation and natural attenuation of pollutants in the coal acid mine drainage (AMD) at Xingren coalfield, Southwest China, are discussed in this paper based on the results of a geochemical investigation as well as geological and hydrogeological background information. The chemical composition of the AMD is controlled by the dissolution of sulfide minerals in the coal seam, the initial composition of the groundwater and the water-rock interaction. The AMD is characterized by high sulfate concentrations, high levels of dissolved metals (Fe, Al, Mn, etc.) and low pH values. Ca2+ and SO4 2- are the dominant cation and anion in the AMD, respectively, while Ca2+ and HCO3 - are present at significant levels in background water and surface water after the drainage leaves the mine site. The pH and alkalinity increase asymptotically with the distance along the flow path, while concentrations of sulfate, ferrous iron, aluminum and manganese are typically controlled by the deposition of secondary minerals. Low concentrations of As and other pollutants in the surface waters of the Xingren coalfield could be due to relatively low quantities being released from coal seams, to adsorption and coprecipitation on secondary minerals in stream sediments, and to dilution by unpolluted surface recharge. Although As is not the most serious water quality problem in the Xingren region at present, it is still a potential environmental problem.

Wu, Pan; Tang, Changyuan; Liu, Congqiang; Zhu, Lijun; Pei, Tingquan; Feng, Lijuan

2009-06-01

313

NGC 4314. II - Hubble Space Telescope I-band surface photometry of the nuclear region  

NASA Astrophysics Data System (ADS)

We present an HST I-band Planetary Camera image of the nuclear region of NGC 4314, an anemic barred galaxy with recent star formation confined to a nuclear ring. These data resolve the nuclear ring into multiple sites of new star formation and resolve associated dust lanes into discrete clouds. Deconvolution results in at least 0.13 arcsec resolution, as demonstrated by the de Vaucouleurs r exp 1/4 law. Contrasted with similar studies of M87 and NGC 7457, we find no photometric evidence for an extreme concentration of stars in the center of NGC 4314. We identify an oval distortion of length 8 arcsec in the nuclear region, using ellipse-fitting routines and the unsharp masked frame. This nuclear bar has newer stars near its ends. We catalog 14 star clusters associated with H II regions in the nuclear ring. As an additional demonstration of the resolution achieved, the integral size distribution of these clusters is described by an exponential relationship which prevails down to 0.14 arcsec.

Benedict, G. F.; Higdon, J. L.; Jefferys, W. H.; Duncombe, R.; Hemenway, P. D.; Shelus, P. J.; Whipple, A. L.; Nelan, E.; Story, D.; McArthur, B.; McCartney, J.; Franz, O. G.; Fredrick, L. W.; van Altena, Wm. F.

1993-04-01

314

Investigating spatial variation in the surface and atmosphere of Pluto through stellar occultations and PSF photometry  

E-print Network

Stellar occultations provide a high-resolution view of a single chord through Pluto's atmosphere. This thesis presents three projects related to stellar occultation observations of Pluto. The first project concerns the ...

Zangari, Amanda Marie

2013-01-01

315

UBV photometry of V934 Her in the X-ray outburst  

NASA Astrophysics Data System (ADS)

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.

Metlova, N. V.; Goranskij, V. P.

2014-09-01

316

Absolute magnitudes for late-type dwarf stars for Sloan photometry  

E-print Network

We present a new formula for absolute magnitude determination for late-type dwarf stars as a function of (g-r) and (r-i) for Sloan photometry. The absolute magnitudes estimated by this approach are brighter than those estimated by colour-magnitude diagrams, and they reduce the luminosity function rather close to the luminosity function of Hipparcos.

S. Bilir; S. Karaali; S. Tuncel

2005-03-18

317

Long-term photometry of variables at ESO. I - The first data catalogue (1982-1986)  

NASA Astrophysics Data System (ADS)

This paper presents the catalog of photometric data in the Stromgren system obtained during the first four years (October 1982 - September 1986) of the Long-Term Photometry of Variables (LTPV) program at ESO. The data are available in computer-readable form.

Manfroid, J.; Sterken, C.; Bruch, A.; Burger, M.; de Groot, M.; Duerbeck, H. W.; Duemmler, R.; Figer, A.; Hageman, T.; Hensberge, H.; Jorissen, A.; Madejsky, R.; Mandel, H.; Ott, H.-A.; Reitermann, A.; Schulte-Ladbeck, R. E.; Stahl, O.; Steenman, H.; Vander Linden, D.; Zickgraf, F.-J.

1991-03-01

318

VizieR Online Data Catalog: gr photometry of Sextans A and Sextans B (Bellazzini+, 2014)  

NASA Astrophysics Data System (ADS)

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. (2 data files).

Bellazzini, M.; Beccari, G.; Fraternali, F.; Oosterloo, T. A.; Sollima, A.; Testa, V.; Galleti, S.; Perina, S.; Faccini, M.; Cusano, F.

2014-04-01

319

Stellar content of nearby galaxies. I - BVRI CCD photometry for IC 1613  

Microsoft Academic Search

BVRI photometry of over 2000 stars in two fields in IC 1613 has been obtained from CCD frames taken at the prime focus of the Canada-France-Hawaii telescope. The disk of IC 1613 is seen to contain stars with a range of ages: (1) young stars indicated by a distinctive plume of luminous blue stars, yellow supergiants, Cepheids, and a smaller

Wendy L. Freedman

1988-01-01

320

Photometry and Spectrophotometry of the New Variable Star IRAS 20192+3025  

Microsoft Academic Search

We present CCD V and Ic band photometry and spectrophotometry of the object IRAS 20192+3025. The results of this study indicate the object to be a red giant of spectral type M4-6 with periodic variations in the light curve at 20.9 and 40.6 days. The resulting variability type is SRB.

J. D. West; D. R. Alexander

2001-01-01

321

CCD Photometry of the Old Open Clusters IC 361 and Berkeley 78  

Microsoft Academic Search

Open clusters are important test particles for probing the formation and evolution of the Milky Way disk. We have undertaken VI CCD photometry of the poorly studied open clusters IC 361 and Berkeley 78. Ages and distances of these clusters have been determined using the Girardi et al.(2002, A&A, 391, 195) isochrones. In this contribution we present the results of

Amy M. Jones; R. Phelps

2007-01-01

322

The reddening to the galaxy IC 342 from CCD BV photometry of its brightest stars  

Microsoft Academic Search

An attempt was made to estimate the reddening for the galaxy IC 342 on the basis of CCD BV photometry obtained for 117 stars brighter than V = 22.0 mag in a field centered near a spiral arm. At V = 19.4 mag, the plume of the main sequence and slightly evolved blue supergiant stars were detected. The plume is

Barry F. Madore; Wendy L. Freedman

1992-01-01

323

SPIRE point source photometry: within the Herschel interactive processing environment (HIPE)  

NASA Astrophysics Data System (ADS)

The different algorithms appropriate for point source photometry on data from the SPIRE instrument on-board the Herschel Space Observatory, within the Herschel Interactive Processing Environment (HIPE) are compared. Point source photometry of a large ensemble of standard calibration stars and dark sky observations is carried out using the 4 major methods within HIPE: SUSSEXtractor, DAOphot, the SPIRE Timeline Fitter and simple Aperture Photometry. Colour corrections and effective beam areas as a function of the assumed source spectral index are also included to produce a large number of photometric measurements per individual target, in each of the 3 SPIRE bands (250, 350, 500 ?m), to examine both the accuracy and repeatability of each of the 4 algorithms. It is concluded that for flux densities down to the level of 30mJy that the SPIRE Timeline Fitter is the method of choice. However, at least in the 250 and 350 ?m bands, all 4 methods provide photometric repeatability better than a few percent down to at approximately 100mJy. The DAOphot method appears in many cases to have a systematic offset of ˜8 % in all SPIRE bands which may be indicative of a sub-optimal aperture correction. In general, aperture photometry is the least reliable method, i.e. largest scatter between observations, especially in the longest wavelength band. At the faintest fluxes, <30mJy, SUSSEXtractor or DAOphot provide a better alternative to the Timeline Fitter.

Pearson, Chris; Lim, Tanya; North, Chris; Bendo, George; Conversi, Luca; Dowell, Darren; Griffin, Matt; Jin, Terry; Laporte, Nicolas; Papageorgiou, Andreas; Schulz, Bernhard; Shupe, Dave; Smith, Anthony J.; Xu, Kevin

2014-07-01

324

ASTROMETRY AND NEAR-INFRARED PHOTOMETRY OF NEPTUNE'S INNER SATELLITES AND RING ARCS  

E-print Network

ABSTRACT We report 1.87 lm photometry and astrometry of the inner satellites (Proteus, Larissa, Galatea.094 (Proteus). The ring arcs display a reddish spectral response similar to the satellites' in the 0.5­1.9 lm wavelength range. If we consider an earlier photometric measurement of Proteus obtained at K band

Schneider, Glenn

325

Sunlight transmission through desert dust and marine aerosols: Diffuse light corrections to Sun photometry and pyrheliometry  

Microsoft Academic Search

Desert dust and marine aerosols are receiving increased scientific attention because of their prevalence on intercontinental scales and their potentially large effects on Earth radiation, climate, other aerosols, clouds, and precipitation. The relatively large size of dust and marine aerosol particles produces scattering phase functions that are strongly forward peaked. Hence Sun photometry and pyrheliometry of these aerosols are more

P. B. Russell; J. M. Livingston; O. Dubovik; S. A. Ramirez; J. Wang; J. Redemann; B. Schmid; M. Box; B. N. Holben

2004-01-01

326

The strongest desert dust intrusion mixed with smoke over the Iberian Peninsula registered with Sun photometry  

Microsoft Academic Search

We present the analysis of the strongest North African desert dust (DD) intrusion that occurred over the Iberian Peninsula (IP) during the last decade, as registered by modern remote sensing techniques like Sun photometry. This event took place from 22 July to 3 August 2004. The most relevant features of this exceptional event, originated over the Saharan desert, were its

V. E. Cachorro; C. Toledano; N. Prats; M. Sorribas; S. Mogo; A. Berjón; B. Torres; R. Rodrigo; J. de la Rosa; A. M. De Frutos

2008-01-01

327

The Reduction of CCD Images for Stellar Photometry on the VATT  

Microsoft Academic Search

We briefly describe a method of organizing all the star field exposures taken in a complete CCD observational run. By a ``CommandLog'' (to be published in J. Astron. Data) one can organize all the observations and process them within IRAF in an orderly, automated manner to arrive at stellar photometry calibrated into a standard photometric system (in our case, Strömvil).

R. Janusz; R. P. Boyle; A. G. Davis Philip

2003-01-01

328

AN UPDATED CATALOG OF M33 CLUSTERS AND CANDIDATES: UBVRI PHOTOMETRY AND SOME STATISTICAL RESULTS  

SciTech Connect

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.

Ma Jun, E-mail: majun@nao.cas.cn [National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100012 (China)

2012-08-15

329

Analysis of Astrometry and Photometry Observations of Asteroids at the RTT150  

E-print Network

, 2007). Considering the time length of the Gaia mission, there will be encounters between asteroids and Earth, as the three year period is comparable to the synodic periods of main belt asteroidsAnalysis of Astrometry and Photometry Observations of Asteroids at the RTT150 Ivantsov, A.1

Boyer, Edmond

330

Four-colour photometry of the spotted dMe-star EY Draconis  

NASA Astrophysics Data System (ADS)

We present the first four-colour photometry and spot modelling of the fast-rotating active star EY Draconis. In the result of the modelling possible spot evolution can be seen. The observed light curve appeared to be stable through 118 rotational cycles.

Vida, K.

2006-09-01

331

Photometry of the spiral pair NGC 450\\/UGC 807 and the optical thickness of galactic disks  

Microsoft Academic Search

CCD images of the non-interacting spiral pair NGC 450 and UGC 807 in B, V, R, and I filters were used to perform photometry on these two Sb spirals. The goal was to determine the absorption suffered by UGC 807 because of the presence of the disk of NGC 450 in the foreground. The color variations observed, the comparison of

Yiannis C. Andredakis; P. C. van der Kruit

1992-01-01

332

NIR photometry the AGN candidate MASTER OTJ005720.90+282557.1  

NASA Astrophysics Data System (ADS)

Following the report on flaring activity of MASTER OTJ005720.90+282557.1 by Balanutsa et al.,2014 (Atel #6686). We carried out NIR photometry recently, On November 17th,2014 (JD2456978.719363), we found this object with a flux corresponding to H = 16.224 +/- 0,07.

Carrasco, L.; Miramon, J.; Porras, A.; Recillas, E.; Leon-Tavares, J.; Chavushyan, V.; Carraminana, A.

2014-11-01

333

Spitzer Photometry of WISE-Selected Brown Dwarf and Hyper-Lumninous Infrared Galaxy Candidates  

NASA Technical Reports Server (NTRS)

We present Spitzer 3.6 and 4.5 micrometer photometry and positions for a sample of 1510 brown dwarf candidates identified by the Wide-field Infrared Survey Explorer (WISE) all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12). Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify seven fainter (4.5 m to approximately 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy candidates. For this control sample, we find another six brown dwarf candidates, suggesting that the seven companion candidates are not physically associated. In fact, only one of these seven Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this, there is no evidence for any widely separated (greater than 20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of 7.33 x 10(exp 5) objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 m photometry, along with positionally matched B and R photometry from USNO-B; J, H, and Ks photometry from Two Micron All-Sky Survey; and W1, W2, W3, and W4 photometry from the WISE all-sky catalog.

Griffith, Roger L.; Kirkpatrick, J. Davy; Eisenhardt, Peter R. M.; Gelino, Christopher R.; Cushing, Michael C.; Benford, Dominic; Blain, Andrew; Bridge, Carrie R.; Cohen, Martin; Cutri, Roc M.; Donoso, Emilio; Jarrett, Thomas H.; Lonsdale, Carol; Mace, Gregory; Mainzer, A.; Marsh, Ken; Padgett, Deborah; Petty, Sara; Ressler, Michael E.; Skrutskie, Michael F.; Stanford, Spencer A.; Stern, Daniel; Tsai, Chao-Wei; Wright, Edward L.; Wu, Jingwen

2012-01-01

334

Destabilization of olivine by 30-keV electron irradiation: a possible mechanism of space weathering affecting interplanetary dust particles and planetary surfaces  

NASA Astrophysics Data System (ADS)

Electron irradiation experiments were performed using a 30-keV electron beam on single crystals of olivine in a scanning electron microscope (SEM) and in an electron microprobe (EMP). We determined that, under certain conditions, structural damage is caused to the irradiated surface of iron-bearing olivines. The irradiated areas comprise spherules with sizes of hundreds of nanometers and micrometer-sized holes. In the immediate vicinities of the irradiated areas, droplets with sizes of tens of nanometers and branching tracks are observed. With increasing total charge, the hundreds of nanometer-sized spherules become larger and more irregular in shape. The size and shape of the nanometer-sized droplets remain almost constant, but their surface density increases (in m -2). Chemical fractionations compared to the initial olivine were found: the irradiated areas are slightly enriched in MgO, whereas the deposits are enriched in SiO 2. Destabilization of olivine is not due to the dissipation of the implanted energy as heat, but results most probably from electrostatic discharges leading to the breakdown of the dielectric lattice. The possibility that such processes could be responsible for significant space weathering of interplanetary dust particles and regoliths of planetary surfaces should be taken into account. In the interplanetary medium, 10-keV range electrons are carried by the solar wind, whereas at 1 AU from the Sun, the lifetime of cometary dust and the exposure time of lunar regolith are, at least, 10 to 100 times greater than the duration required to accumulate the damaging electronic doses applied in this study. Moreover, the comparison of the microstructures of samples irradiated in the present study with features of lunar regolith grains reveals several chemical and structural similarities.

Lemelle, L.; Beaunier, L.; Borensztajn, S.; Fialin, M.; Guyot, F.

2003-05-01

335

Geohydrology of the aquifers that may be affected by the surface mining of coal in the Fruitland Formation in the San Juan Basin, northwestern New Mexico  

USGS Publications Warehouse

A monitoring network of 50 wells was installed from 1975 to 1979 in the surface-mineable coal area. The purpose of the network was to collect hydrologic data and to establish a data base. The hydrologic data consist of water level measurements, water chemistry, and selected aquifer characteristics. The four aquifers considered in this study are: (1) The Pictured Cliffs Sandstone; (2) coal seams and interbedded lithologic units of the Fruitland Formation; (3) overburden of the Kirtland Shale and Fruitland Formation; and (4) the alluvium along the Chaco River and its eastern and northeastern tributaries. Five sites were selected for study. Four of these sites, Western Coal Company 's lease near Fruitland, Bisti West, Kimbeto, and Ojo Encino, have surface-mineable coal. The Chaco River alluvium was selected because it is downstream from anticipated mining activity. The specific conductances of the representative water samples from selected wells in the 4 aquifers in the 5 study areas ranged from 800 to 23,000 microsiemens/cm at 25 C. The dominant cation in all samples was sodium. The water is brackish in the Pictured Cliffs Sandstone and in the coal seams and interbedded lithologic units of the Fruitland Formation. It is fresh to saline in the overburden of the Fruitland Shale and Fruitland Formation, and fresh to brackish in the Chaco River alluvium. (Author 's abstract)

Myers, R.G.; Villanueva, E.D.

1986-01-01

336

The Calibration of the Swift/UVOT Optical Observations: A Recipe for Photometry  

E-print Network

Swift/UVOT has the capability to provide critical insight into the physics of the early afterglows of gamma-ray bursts (GRBs). But without precise calibration of the UVOT to standard photometric systems, it is impossible to leverage late- time, ground-based follow-up data to the early-time UVOT observations. In this paper, we present a calibration of the Swift/UVOT photometry to the standard Johnson UBV system for the UVOT UBV filters,and a step-by-step photometry recipe for analyzing these data. We base our analysis on aperture photometry performed on the ground-based and UVOT observations of the local standard stars in the fields of supernovae (SNe) 2005am and 2005cf, and a number of Landolt standard stars.We find that the optimal photometry aperture radius for UVOT data is small (2".5 for unbinned data,3".0 for 2X2 binned data),and show that the coincidence- loss (C-loss) correction is important even for relatively faint magnitudes (mag 16 to 19). Based on a theoretically motivated model,we fit the C-loss correction with two parameters, the photometric zero point (ZP) and the saturation magnitude (m_inf), and derive tight constraints for both parameters [sigma(ZP) = 0.01 mag and sigma(m_inf) = 0.02 mag)].We find that the color term correction is not necessary for the UVOT B and V filters,but is necessary for the U filter for blue objects [(U - V) < 0.4 mag]. We also apply our calibration results to the UVOT observations of GRB 050603. There is a scatter of ~0.04--0.08 mag in our final UVOT photometry, the cause of which is unclear, but may be partly due to the spatial variation in the pixel sensitivity of the UVOT detector.

Weidong Li; Saurabh Jha; Alexei V. Filippenko; Joshua S. Bloom; David Pooley; Ryan J. Foley; Daniel A. Perley

2005-05-25

337

Mars surface albedo and changes  

E-print Network

The pervasive Mars dust is continually transported between surface and atmosphere. When on the surface, dust increases the albedo of darker underlying rocks and regolith, which modifies climate energy balance and must be quantified. Remote observation of surface albedo absolute value and albedo change is however complicated by dust itself when lifted in the atmosphere. Here we present a method to calculate and map the bolometric solar hemispherical albedo of the Martian surface using the 2004 - 2010 OMEGA imaging spectrometer dataset. This method takes into account aerosols radiative transfer, surface photometry, and instrumental issues such as registration differences between visible and near-IR detectors. Resulting albedos are on average 17% higher than previous estimates for bright surfaces while similar for dark surfaces. We observed that surface albedo changes occur mostly during the storm season due to isolated events. The main variations are observed during the 2007 global dust storm and during the fol...

Vincendon, Mathieu; Altieri, Francesca; Ody, Anouck

2014-01-01

338

A Response Surface Methodology study on the role of factors affecting growth and volatile phenol production by Brettanomyces bruxellensis ISA 2211 in wine.  

PubMed

The present study was aimed at determining the effect of glucose, ethanol and sulphur dioxide on the growth and volatile phenol production by Brettanomyces bruxellensis in red wines using a response surface methodology approach. Sulphur dioxide proved to have a significant (p < 0.05) negative linear and quadratic effect on growth and 4-ethylphenol production. Concentrations of sulphur dioxide higher than 20 mg L(-1), at pH 3.50, induced immediate loss of cell culturability under growth permissive levels of ethanol. Under high ethanol concentrations (14% v/v), the lag phase increased from 3 to 10 days, growth being fully arrested at 15% (v/v). Glucose up to 10 g L(-1) was found to be a significant factor (quadratic level) in biomass increase under low ethanol (<12.5% v/v) and low sulphite concentrations. However, when cells were inactivated by sulphur dioxide and ethanol, glucose (up to 10 g L(-1)) did not prevent cell death. Production of more than 50 ?g L(-1) day(-1) of 4-ethylphenol was only observed in the presence of high numbers (10(6) CFU mL(-1)) of culturable cells, being stimulated by increasing glucose concentrations. PMID:24929715

Chandra, M; Barata, A; Ferreira-Dias, S; Malfeito-Ferreira, M; Loureiro, V

2014-09-01

339

Visible Color and Photometry of Bright Materials on Vesta  

NASA Technical Reports Server (NTRS)

The Dawn Framing Camera (FC) collected images of the surface of Vesta at a pixel scale of 70 m in the High Altitude Mapping Orbit (HAMO) phase through its clear and seven color filters spanning from 430 nm to 980 nm. The surface of Vesta displays a large diversity in its brightness and colors, evidently related to the diverse geology [1] and mineralogy [2]. Here we report a detailed investigation of the visible colors and photometric properties of the apparently bright materials on Vesta in order to study their origin. The global distribution and the spectroscopy of bright materials are discussed in companion papers [3, 4], and the synthesis results about the origin of Vestan bright materials are reported in [5].

Schroder, S. E.; Li, J. Y.; Mittlefehldt, D. W.; Pieters, C. M.; De Sanctis, M. C.; Hiesinger, H.; Blewett, D. T.; Russell, C. T.; Raymond, C. A.; Keller, H. U.

2012-01-01

340

The NEAT database photometry and constraints on the rotation of 5535 AnneFrank.  

NASA Astrophysics Data System (ADS)

In November of 2002, the main belt asteroid 5535 Annefrank was observed over a 26-minute window with the Stardust spacecraft. During this time, the first spacecraft images of this S-class asteroid were taken over ~40% of the surface at a resolution of 185-300 m/pixel (Duxbury et al. 2004). Stardust collected 72 images at varying phase angles, producing a phase curve out to 134 degrees and a geometric albedo of 0.24. Annefrank's orientation, shape and size were constrained by the encounter's imaging data, revealing a minimum triaxial ellipsoid size of 6.6 x 5.0 x 3.4 km, and irregular topography, including a protrusion along the end of its longest axis. Owing to the brevity of the observing window no constraints on the rotational period or spin axis orientation were made by the encounter, and Annefrank is assumed to be a slow-rotator. Thus, we began a campaign to observe Annefrank in May of 2005 through December of 2006 using the 0.6 meter telescope at Table Mountain Observatory, run by Caltech's/Jet Propulsion Laboratory (JPL). A total of 14 nights of observation yielded a light curve with possible rotational periods of 0.48, 0.63, and 0.95 days, so that further constrains were required to determine its rotation and spin axis orientation. The Near-Earth Asteroid Tracking (NEAT) project at JPL has systematically observed the sky for more than a decade. While the main objective of NEAT is the discovery of near-earth objects (NEOs), the NEAT database provides multiple observations over varying time scales (hours, days, months and years). As a result, the NEAT database provides a history of behavior over a time span of more than ten years and can serve as a powerful tool to analyze the time-dependent nature of solar system bodies. We use the NEAT database here to conduct a photometric study of 5535 Annefrank to better constrain the period and derive an orientation of the spin axis. The data have also been used to conduct photometry and derive phase curves of bright outer solar system objects, and we present a subset of these results as well. This research was funded in part by NASA through the Discovery Data Analysis Program. This work was performed in part at the Jet Propulsion Laboratory operated by the California Institute of Technology under contract with NASA.

Bauer, J. M.; Schmidt, B. E.; Lawrence, K. J.; Buratti, B. J.; Eckel, J.; Petersen, P.; Hillier, J. K.

2007-12-01

341

Resolved photometry of Vesta reveals physical properties of crater regolith  

NASA Astrophysics Data System (ADS)

During its year-long orbital mission, the Dawn spacecraft has mapped the surface of main-belt asteroid Vesta multiple times at different spatial resolutions and illumination and viewing angles. The onboard Framing Camera has acquired thousands of clear filter and narrow band images, which, with the availability of high-resolution global shape models, allows for a photometric characterization of the surface in unprecedented detail. We analyze clear filter images to retrieve the photometric properties of the regolith. In the first part of the paper we evaluate different photometric models for the global average. In the second part we use these results to study variations in albedo and steepness of the phase curve over the surface. Maps of these two photometric parameters show large scale albedo variations, which appear to be associated with compositional differences. They also reveal the location of photometrically extreme terrains, where the phase curve is unusually shallow or steep. We find that shallow phase curves are associated with steep slopes on crater walls and faults, as calculated from a shape model. On the other hand, the phase curve of ejecta associated with young impact craters is steep. We interpret these variations in phase curve slope in terms of physical roughness of the regolith. The lack of rough ejecta around older craters suggests that initially rough ejecta associated with impact craters on Vesta are smoothed over a relatively short time of several tens of Myr. We propose that this process is the result of impact gardening, and as such represents a previously unrecognized aspect of Vesta space weathering (Pieters et al., 2012). If this type of space weathering is common, we may expect to encounter this photometric phenomenon on other main belt asteroids.

Schröder, S. E.; Mottola, S.; Keller, H. U.; Raymond, C. A.; Russell, C. T.

2013-09-01

342

Resolved Photometry of Vesta Reveals Physical Properties of Crater Regolith  

NASA Astrophysics Data System (ADS)

During its year-long orbital mission, the Dawn spacecraft mapped the surface of main-belt asteroid Vesta multiple times at different spatial resolutions and illumination and viewing angles. The on-board Framing Camera acquired thousands of clear filter and narrow band images, which, with the availability of high-resolution global shape models, allows for a photometric characterization of the surface in unprecedented detail. We analyze clear filter images to retrieve the photometric properties of the regolith. We evaluate different photometric models for the global average, and use these results to study variations in albedo and steepness of the phase curve over the surface. Maps of these two photometric parameters show large scale albedo variations that appear to be associated with compositional differences. They also reveal the location of photometrically extreme terrains, where the phase curve is unusually shallow or steep. We find that shallow phase curves are associated with steep slopes on crater walls and faults. On the other hand, the phase curve of ejecta associated with young impact craters is steep. We interpret these variations in phase curve slope in terms of physical roughness of the regolith. The lack of rough ejecta around older craters suggests that initially rough ejecta associated with impact craters on Vesta are smoothed over a relatively short time of several tens of Myr. This process appears to be the result of impact gardening, and as such represents a previously unrecognized aspect of Vesta space weathering. We may expect to encounter this photometric phenomenon on other main belt asteroids.

Schroeder, Stefan; Mottola, S.; Keller, U.; Raymond, C.; Russell, C.

2013-10-01

343

How does nature of rain affect micro-physical parameters of surface rain? A study on vertical profile and surface rain micro-structure over eastern Himalaya in India  

NASA Astrophysics Data System (ADS)

A study has been made on the effect of nature of the rain (convective, stratiform and mixed) on the various micro-physical properties like drop-size distributions (DSD), fall velocity and rain rate of surface rain over Darjeeling (27.01 (°) N, 88.15 (°) E), a high altitude (2200 m asl) station at eastern Himalaya in India. A vertical looking Micro Rain Radar (MRR) was used for the vertical profile of micro-physical parameters of rain along with the rain height derived from the bright band structure of melting layer of radar reflectivity profile. The micro-physical parameters of surface rain was obtained using a ground based Disdrometer. Data has been collected and analysed for all the rain events during monsoon (June-September), 2013. All the rain events over the entire study period were classified as convective, stratiform and mixed type based on the bright band structure. DSD, fall velocity of rain drops and rain rate obtained from Disdrometer were correlated with the types of rain obtained from MRR. Our results showed that the average height of bright band of melting layer was 2.5 km and 4 km for convective and stratiform type of rain respectively. For mixed type of rain radar reflectivity shows two peaks with the bright band heights ranging from 2 - 5 km. Convective rain events showed higher rain rate at the ground with the range of 30-40 mm hr (-1) . Instantaneous rain rate of convective rain events sometimes reached more than 100 mm hr (-1) . DSD at the surface showed that number of bigger drops (> 0.5 mm) increases significantly compared to smaller drops (< 0.5 mm) along with higher fall velocities. The drop diameter for this type of rain reached 5 mm for most of the cases. For stratiform type of rain, surface rain rate was found to be comparatively much lower remaining around 5 mm hr (-1) . The number of bigger drops was much lower associated to stratiform type of rain. The drop diameter remained within 2 mm for most of the cases. Several events were observed where all types of rains occurred with convective rains appeared at the initial phase of rain followed by mixed type and both of them lasted for low duration. Stratiform rains which appeared after the mixed type lasted for longer duration till the end of the events. The individual characteristics for each type of rains were distinctly observed for the events where all these three types were present. These distinctly different features of different rain types could significantly impact on the washing or scavenging air pollutants below the cloud with different potentials.

Singh, Soumendra; Chatterjee, Abhijit; Ghosh, Sanjay; Raha, Sibaji; Mitra, Amitabha

344

CCD Photometry of NGC 2482 and Five Previously Unobserved Open Star Clusters  

E-print Network

We present BV and u'g'r'i' CCD photometry of the central region of NGC 2482. We also present BVu'g' CCD photometry of five clusters that have been poorly studied in the past: Ruprecht 42, Ruprecht 51, Ruprecht 153, Ruprecht 154; and AH03 J0748-26.9, which to our knowledge has not been studied before. Using a global optimization technique that eliminates much of the subjectivity previously inherent in main sequence fitting studies, we obtain values of the distances, ages, and metallicities of the clusters, with robust estimates of the uncertainties of these fundamental parameters. Four of our clusters are less than ~1.3 kpc beyond the Sun's distance from the Galactic Center and have essentially solar metallicity. The metallicities of those clusters more distant from the Galactic Center are consistent with a 0.3 dex step to lower [Fe/H] found in other studies.

Krisciunas, Kevin; Dias, Wilton

2014-01-01

345

VizieR Online Data Catalog: Long-term photometry of Variables I. (Manfroid+ 1991)  

NASA Astrophysics Data System (ADS)

This is the first catalogue of photometric data in the Stroemgren system obtained during the period October 1982 - September 1986. Full description can be found in ESO report SP 8. Since our goal is not absolute (all-sky) photometry, the observations should be used for differential photometry only. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 5 of paper) ------------------------------------ System y b-y m1 c1 ------------------------------------ 1 0.0109 0.0088 0.0133 0.0136 4 0.0068 0.0057 0.0079 0.0118 5 0.0087 0.0070 0.0114 0.0114 6 0.0090 0.0078 0.0126 0.0132 7 0.0071 0.0033 0.0041 0.0065 ------------------------------------ (2 data files).

Manfroid, J.; Sterken, C.; Bruch, A.; Burger, M.; de Groot, M.; Duerbeck, H. W.; Duemmler, R.; Figer, A.; Hageman, T.; Hensberge, H.; Jorissen, A.; Madejsky, R.; Mandel, H.; Ott, H. A.; Reitermann, A.; Schulte-Ladbeck, R. E.; Stahl, O.; Steenman, H.; Vander Linden, D.; Zickgraf, F. J.

1995-11-01

346

Estimations of orbital parameters of exoplanets from transit photometry by using dynamical constraints  

E-print Network

The probability of the detection of Earth-like exoplanets may increase in the near future after the launch of the space missions using the transit photometry as observation method. By using this technique only the semi-major axis of the detected planet can be determined, and there will be no information on the upper limit of its orbital eccentricity. However, the orbital eccentricity is a very important parameter, not only from a dynamical point of view, since it gives also information on the climate and the habitability of the Earth-like planets. In this paper a possible procedure is suggested for confining the eccentricity of an exoplanet discovered by transit photometry if an already known giant planet orbits also in the system.

Zsolt Sandor

2006-06-01

347

UBVRI and H? Photometry of the Young Open Cluster NGC 6530  

NASA Astrophysics Data System (ADS)

New UBVRI and H? photometry has been obtained for the young open cluster NGC 6530 located 10' east of the Lagoon Nebula (M8). We found 37 pre-main-sequence (PMS) stars with H? emission and nine PMS candidates using the R-H? color, a measure of H? emission. From this new photometry we derived the cluster parameters (V0-MV=11.25+/-0.1 mag and =0.35 mag), typical age (1.5 Myr), and an age spread of about 5 Myr. We confirmed the presence of a small amount of differential reddening across the cluster. We also verified the abnormal reddening law for the cluster, especially for a heavily embedded O7 V star, Herschel 36. Comparisons were made for several PMS evolution models with regard to the resulting age distribution and the initial mass function.

Sung, Hwankyung; Chun, Moo-Young; Bessell, Michael S.

2000-07-01

348

Employing the Technology of Virtual Observatory as the Fundamental Framework for the CCD Photometry Survey  

NASA Astrophysics Data System (ADS)

The project of Ond?ejov Southern Photometry Survey (OSPS) is an attempt to exploit the wealth of temporal information contained in multi-colour CCD photometry obtained with 1.54m Danish telescope at La Silla in remote observing mode by several groups of Czech astronomers working on different scientific programs and various primary targets. The OSPS realizes the idea of an automatic extraction of multi-colour light curves from every celestial object identified in the frame, thus giving access to 99% of data normally disposed by the PI's, who usually measure only few targets in every CCD frame. The Virtual Observatory (VO) technology is exploited here as an integral part of previewing, data reduction, bookkeeping, method of analysis and publishing.

Škoda, P.; Hroch, F.; Nádvorník, J.; Mikhailova, D.

2014-05-01

349

UBVRI CCD Photometry of the Type IC Supernova SN 1994I in M51 : The First two months  

Microsoft Academic Search

We present UBVRI CCD Photometry of the Type Ic supernova SN 1994I in M51 which was discovered on April 2, 1994(UT). UBVRI CCD Photometry of SN 1994I were obtained for the period of the first two months from April 4, 1994, using the Seoul National University Observatory 60cm telescope. The light curves of SN 1994I show several interesting features :

Myung Gyoon Lee; Eunhyeuk Kim; Sang Chul Kim; Seung Li Kim; Won-Kee Park; Tae Soo Pyo

1995-01-01

350

CoRoT photometry and high-resolution spectroscopy of the interacting eclipsing binary AU Monocerotis  

Microsoft Academic Search

Analyses of very accurate CoRoT space photometry, past Johnson V photoelectric photometry and high-resolution echelle spectra led to the determination of improved and consistent fundamental stellar properties of both components of AU Monocerotis. We derived new, accurate ephemerides for both the orbital motion (with a period of ) and the long-term, overall brightness variation (with a period of ) of

M. Desmet; Y. Frémat; F. Baudin; P. Harmanec; P. Lampens; E. Janot Pacheco; M. Briquet; P. Degroote; C. Neiner; P. Mathias; E. Poretti; M. Rainer; K. Uytterhoeven; P. J. Amado; J.-C. Valtier; A. Prsa; C. Maceroni; C. Aerts

2010-01-01

351

BVRI CCD photometry of the metal-poor globular cluster M68 (NGC 4590)  

SciTech Connect

BVRI photometry of the low metallicity globular cluster M68 (NGC 4590) was obtained with a CCD camera and the 2.2-m ESO telescope. The resulting BV color-magnitude diagrams are compared with the observations of McClure et al. (1987). The observations are also compared with theoretical isochrones, yielding a cluster age of 13 Gyr with a likely external uncertainty of 2 or 3 Gyr. 25 refs.

Alcaino, G.; Liller, W.; Alvarado, F.; Wenderoth, E. (Ministerio de Educacion de Chile, Santiago (Chile))

1990-06-01

352

13-color photometry of pre-main sequence stars - Preliminary report and results  

NASA Astrophysics Data System (ADS)

Broad (UBVRI) and intermediate (13-color) band photometry of 160 stars selected mainly from the Herbig Rao catalogue are being carried on currently, mainly to complement the published data of these stars in the optical window (for example shortward of the Balmer and longward of the Paschen discontinuities). The 13-color photometric system and its applications to pre-main sequence stars are briefly discussed. First results are presented.

Chavarria-K., C.; de Lara, E.

1981-12-01

353

NIR photometry the AGN candidate MASTER OTJ203431.37+641048.8  

NASA Astrophysics Data System (ADS)

Following the report on flaring activity of MASTER OTJ203431.37+601048.8 by Denisenko et al.,2014 (Atel #6470). We carried out NIR photometry recently, On October 4th,2014 (JD2456934.7287), we found this object with fluxes corresponding to J = 13,739 +/- 0.02, H = 11.494 +/- 0,03 and Ks = 10.667 +/- 0.03.

Carrasco, L.; Porras, A.; Recillas, E.; Leon-Tavares, J.; Chavushyan, V.; Carraminana, A.

2014-10-01

354

Photometry of VdBH 222 stars and field stars (Marco+, 2014)  

NASA Astrophysics Data System (ADS)

We obtained UBVR photometry of VdBH 222 using the ESO Faint Object Spectrograph and Camera (EFOSC2) on the NTT on the night of 24 June 2012. The instrument was equipped with CCD#40, which is a Loral/Lesser, thinned, AR-coated, UV-flooded, and MPP chip that is controlled by ESO-FIERA. It covers a field of view of and has a pixel scale of 0.12". (4 data files).

Marco, A.; Negueruela, I.; Gonzalez-Fernandez, C.; Maiz Apellaniz, J.; Dorda, R.; Clark, J. S.

2014-05-01

355

In Pursuit of LSST Science Requirements: A Comparison of Photometry Algorithms  

E-print Network

We have developed an end-to-end photometric data processing pipeline to compare current photometric algorithms commonly used on ground-based imaging data. This testbed is exceedingly adaptable, and enables us to perform many research and development tasks, including image subtraction and co-addition, object detection and measurements, the production of photometric catalogs, and the creation and stocking of database tables with time-series information. This testing has been undertaken to evaluate existing photometry algorithms for consideration by a next-generation image processing pipeline for the Large Synoptic Survey Telescope (LSST). We outline the results of our tests for four packages: The Sloan Digital Sky Survey's (SDSS) Photo package, Daophot and Allframe, DoPhot, and two versions of Source Extractor (SExtractor). The ability of these algorithms to perform point-source photometry, astrometry, shape measurements, star-galaxy separation, and to measure objects at low signal-to-noise is quantified. We also perform a detailed crowded field comparison of Daophot and Allframe, and profile the speed and memory requirements in detail for SExtractor. We find that both Daophot and Photo are able to perform aperture photometry to high enough precision to meet LSST's science requirements, and less adequately at PSF-fitting photometry. Photo performs the best at simultaneous point and extended-source shape and brightness measurements. SExtractor is the fastest algorithm, and recent upgrades in the software yield high-quality centroid and shape measurements with little bias towards faint magnitudes. Allframe yields the best photometric results in crowded fields.

Andrew C. Becker; Nicole M. Silvestri; Russell E. Owen; Zeljko Ivezic; Robert H. Lupton

2007-12-05

356

CCD photometry of the globular cluster M2: RR Lyrae physical parameters and new variables  

Microsoft Academic Search

We report the results of CCD V and R photometry of the RR Lyrae stars in M2. The periodicities of most variables are revised and new ephemerides are calculated. Light-curve decomposition of the RR Lyrae stars was carried out and the corresponding mean physical parameters [Fe\\/H] = -1.47, Teff = 6276K, logL = 1.63Lsolar and MV = 0.71 from nine

C. Lázaro; A. Arellano Ferro; M. J. Arévalo; D. M. Bramich; S. Giridhar; E. Poretti

2006-01-01

357

Photometry and Polarimetry Of Point-Sources With The COBE(*) \\/DIRBE Datasets  

Microsoft Academic Search

The COBE DIRBE data archive contains a unique record of bright IR point source observations over the entire sky. Point source photometry (1.25-240 mu m) and polarimetry (1.25-3.5 mu m) derived from these data permit the study of stellar energy distributions, variability, and polarization. This poster reviews the extraction of fluxes of point-sources from the DIRBE time-ordered data, and presents

G. Berriman; K. J. Mitchell; J. Gales; S. W. Stemwedel; T. Kelsall; D. Richardson; J. A. Skard

1995-01-01

358

Photometry Data Coding for Three-Dimensional Mesh Models Using Connectivity and Geometry Information  

Microsoft Academic Search

\\u000a In this paper, we propose new predictive coding schemes for photometry data of three-dimensional (3-D) mesh models as per-vertex\\u000a binding. We exploit geometry and connectivity information to enhance coding efficiency of the color and normal vector data.\\u000a For color coding, we predict the color of the current vertex by a weighted sum of colors of adjacent vertices considering\\u000a angles between

Young-suk Yoon; Sung-yeol Kim; Yo-sung Ho

2005-01-01

359

K-band transit and secondary eclipse photometry of exoplanet OGLE-TR-113b  

Microsoft Academic Search

We present high-precision K-band photometry of the transit and secondary eclipse of extrasolar planet OGLE-TR-113, using the SOFI near-infrared instrument on European Southern Observatory's New Technology Telescope. Data were taken in 5-s exposures over two periods of 3-4 h, using random jitter position offsets. In this way, a relative photometric precision of ~1 per cent per frame was achieved, avoiding

I. A. G. Snellen; E. Covino

2007-01-01

360

New Cepheid distances to nearby galaxies based on BVRI CCD photometry. I - IC 1613  

Microsoft Academic Search

BVRI CCD photometric observations of 11 previously known Cepheids in IC 1613 have been obtained at the Canada-France-Hawaii telescope. These new Cepheid data, in conjunction with recent near-infrared photometry, are used to estimate the mean total extinction for the Cepheids and to provide a distance to the galaxy. A true distance modulus to IC 1613 of 24.3 + or -0.1

Wendy L. Freedman

1988-01-01

361

UBV(Ikc) CCD Photometry of Young Open Clusters. I. IC 1805  

Microsoft Academic Search

The UBVIkc CCD photometry was performed in the central region(about 20'x20x) of the extremely young open cluster IC 1805. Member stars were selected in the (B-V) - (U-B) and (V-I) - (B-V) color-color planes. Applying recent stellar evolutionary models, we derived the age, age-spread, and initial mass function(IMF) of the cluster. IC 1805 was found to be an extremely young(t_age

Hwankyung Sung; See-Woo Lee

1995-01-01

362

CCD uvbyHbeta Photometry in Clusters: I. The Open Cluster Standard, IC 4651  

Microsoft Academic Search

CCD photometry of the intermediate-age open cluster, IC 4651, on the\\u000auvbyHbeta system is presented and analyzed. By using a combination of the\\u000ainformation from the color-magnitude diagram (CMD) and the color-color\\u000adiagrams, a sample of 98 highly probable main sequence cluster members with\\u000ahigh photometric accuracy is isolated. From this sample, adopting the intrinsic\\u000acolor relation of Olsen (1988),

B. J. Anthony-Twarog; B. A. Twarog

1999-01-01

363

VI CCD Photometry of the Old Open Clusters IC 361 and Berkeley 78  

Microsoft Academic Search

Open clusters are important test particles for probing the formation and evolution of the Milky Way disk. We have undertaken VI CCD photometry of the poorly studied open clusters IC 361 and Berkeley 78. Ages, reddenings [E(V-I)], Heliocentric distances [d], apparent distance moduli [(m-M)v], true distance moduli [(m-M)o], Galactocentric radii [RGC], and vertical distances for the plane [z] for these

Amy Jones; Randy Phelps

2007-01-01

364

CCD photometry of late-type stars in the young open cluster IC 2602  

Microsoft Academic Search

We present the results of VRI photometry of the young open cluster IC 2602. Two 15 arcmin times 15 arcmin fields were observed in February and May 1991 using the 1-m Swope telescope at Las Campanas. Using theoretical isochrones obtained from \\\\cite[D'Antona & Mazzitelli (1994)]{dam94}, and allowing for observational and other uncertainties, we identify 78 primary candidate members with 12

D. C. Foster; P. B. Byrne; S. L. Hawley; W. R. J. Rolleston

1997-01-01

365

CCD UVBY Hbeta Photometry in Clusters. I. The Open Cluster Standard, IC 4651  

Microsoft Academic Search

CCD photometry of the intermediate-age open cluster IC 4651 on the uvbyHbeta system is presented and analyzed. By using a combination of the information from the color-magnitude diagram (CMD) and the color-color diagrams, a sample of 98 highly probable main-sequence cluster members with high photometric accuracy is isolated. From this sample, adopting the intrinsic color relation of Olsen, E(b-y)=0.062+\\/-0.003 and

Barbara J. Anthony-Twarog; Bruce A. Twarog

2000-01-01

366

Resetting the Star: Uncovering New Warm Debris Disks using High-acccuracy IRAC Photometry  

NASA Astrophysics Data System (ADS)

Debris disks trace the collisional breakdown of asteroid and comet parent bodies orbiting nearby main sequence stars. The most common type is a cold analog of our Kuiper belt with emission peaking near 70 microns wavelength. Less than 10% of known debris disks show warm emission at 22 or 24 microns. Warm debris disks are especially interesting because they trace material in the terrestrial planet zones analogous to our inner solar system. Their short dynamical time scales make them proxies stellar youth, for high levels of gravitational stirring by massive planets, or as tracers of recent collisions between large planetesimals. The Wide-Field Infrared Survey Explorer (WISE) has completed a new, sensitive all-sky mapping in the 3.3, 4.6, 12, and 22 micron bands. Using the WISE photometry alone, Padgett et al. (2013) were able to identify 346 Hipparcos stars as new, warm debris disk sources with 22 micron emission > 4 sigma above the stellar photosphere. A substantial additional number of nearby Hipparcos stars show excess emission at the 3 sigma level but require confirmation. IRAC subarray photometry at S/N of >= 100 provides a way to achieve this confirmation by measuring the stellar photospheric brightness to 3-4 times better accuracy at 3.6 microns than WISE itself has done at the same wavelength. We propose to make such measurements for 421 Hipparcos stars which show indications of WISE 22 micron excess, and for which the improved 3.6 micron photometry would result in a 4 sigma excess detection. An additional 131 stars with Spitzer/MIPS 24 micron photometry will be observed toward the same goal of enabling the detection of weaker excesses through better characterization of the stellar photospheric emission. This program should almost double the number of warm debris disks discovered by WISE around nearby Hipparcos stars. This expanded sample will provide prime targets for imaging of self-luminous exoplanets and for spectroscopic characterization of mineralogical features using JWST.

Stapelfeldt, Karl; Padgett, Deborah; Su, Kate

2012-12-01

367

Galaxy and Mass Assembly: FUV, NUV, ugrizYJHK Petrosian, Kron and Sérsic photometry  

Microsoft Academic Search

In order to generate credible 0.1-2 mum spectral energy distributions, the Galaxy and Mass Assembly (GAMA) project requires many gigabytes of imaging data from a number of instruments to be reprocessed into a standard format. In this paper, we discuss the software infrastructure we use, and create self-consistent ugrizYJHK photometry for all sources within the GAMA sample. Using UKIDSS and

David T. Hill; Lee S. Kelvin; Simon P. Driver; Aaron S. G. Robotham; Ewan Cameron; Nicholas Cross; Ellen Andrae; Ivan K. Baldry; Steven P. Bamford; Joss Bland-Hawthorn; Sarah Brough; Christopher J. Conselice; Simon Dye; Andrew M. Hopkins; Jochen Liske; Jon Loveday; Peder Norberg; John A. Peacock; Scott M. Croom; Carlos S. Frenk; Alister W. Graham; D. Heath Jones; Konrad Kuijken; Barry F. Madore; Robert C. Nichol; Hannah R. Parkinson; Steven Phillipps; Kevin A. Pimbblet; Cristina C. Popescu; Matthew Prescott; Mark Seibert; Rob G. Sharp; Will J. Sutherland; Daniel Thomas; Richard J. Tuffs; Elco van Kampen

2011-01-01

368

Documentation for the machine-readable version of the thirteen color photometry of 1380 bright stars  

NASA Technical Reports Server (NTRS)

The magnetic tape version of the catalogue of thirteen-color photometry of 1380 bright stars, containing data on the 13 color medium narrow band photometric system is described. Observations of essentially all stars brighter than fifth visual magnitude north of delta = -20 deg and brighter than fourth visual magnitude south of delta = -20 deg are included. It is intended to enable users to read and process the tape without the common difficulties and uncertainties.

Warren, W. H., Jr.; Roman, N. G.

1981-01-01

369

Comparison of Atmospheric Parameters Determined from Spectroscopy and Photometry for DA White Dwarfs in the Sloan Digital Sky Survey  

NASA Astrophysics Data System (ADS)

We present a comparative analysis of atmospheric parameters obtained with the so-called photometric and spectroscopic techniques. Photometric and spectroscopic data for 1360 DA white dwarfs from the Sloan Digital Sky Survey (SDSS) are used, as well as spectroscopic data from the Villanova White Dwarf Catalog. We first test the calibration of the ugriz photometric system by using model atmosphere fits to observed data. Our photometric analysis indicates that the ugriz photometry appears well calibrated when the SDSS to AB95 zeropoint corrections are applied. The spectroscopic analysis of the same data set reveals that the so-called high-log g problem can be solved by applying published correction functions that take into account three-dimensional hydrodynamical effects. However, a comparison between the SDSS and the White Dwarf Catalog spectra also suggests that the SDSS spectra still suffer from a small calibration problem. We then compare the atmospheric parameters obtained from both fitting techniques and show that the photometric temperatures are systematically lower than those obtained from spectroscopic data. This systematic offset may be linked to the hydrogen line profiles used in the model atmospheres. We finally present the results of an analysis aimed at measuring surface gravities using photometric data only.

Genest-Beaulieu, C.; Bergeron, P.

2014-12-01

370

Hubble Space Telescope photometry of the central regions of Virgo Cluster elliptical galaxies. 1: Observations, discussion, and conclusions  

NASA Technical Reports Server (NTRS)

Using the Hubble Space Telescope we have observed at 10 pc resolution the nuclei of a luminosity-limited sample of 14 E and E/SO galaxies in the Virgo Cluster with magnitudes B(sub T) = 9.4 to 13.4. In this paper we present the images, and discuss the results of the detailed analysis of the surface photometry given in two companion papers. We find that the nuclear and near-nuclear morphologies confirm and strengthen the previously recognized dichotomy of 'E' galaxies into 'true' and 'disky' subtypes. The latter, usually classified E4 or later, often show a bright nuclear disk of radius approximately 100 pc. Essentially all early-type galaxies with -18 greater than M(sub B) greater than -20 are disky. Most true E galaxies are classified E4 or earlier. Most galaxies of both types show dust in the nuclear regions, the most remarkable example being a compact dust disk in NGC 4261. Other than dust, no anomalies were detected in the centers of the three galaxies in our sample which show clear kinematic evidence for a decoupled component.

Jaffe, Walter; Ford, Holland C.; O'Connell, Robert W.; Bosch, Frank C. Van Den; Ferrarese, Laura

1994-01-01

371

HIIphot: Automated Photometry of HII Regions Applied to M51  

E-print Network

We have developed a robust, automated method, hereafter designated HIIphot, which enables accurate photometric characterization of HII regions while permitting genuine adaptivity to irregular source morphology. HIIphot utilizes object-recognition techniques to make a first guess at the shapes of all sources then allows for departure from such idealized ``seeds'' through an iterative growing procedure. Photometric corrections for spatially coincident diffuse emission are derived from a low-order surface fit to the background after exclusion of all detected sources. We present results for the well-studied, nearby spiral M51 in which 1229 HII regions are detected above the 5-sigma level. A simple, weighted power-law fit to the measured H-alpha luminosity function (HII LF) above log L_H-alpha = 37.6 gives alpha = -1.75+/-0.06, despite a conspicuous break in the HII LF observed near L_H-alpha = 10^38.9. Our best- fit slope is marginally steeper than measured by Rand (1992), perhaps reflecting our increased sensitivity at low luminosities and to notably diffuse objects. HII regions located in interarm gaps are preferentially less luminous than counterparts which constitute M51's grand-design spiral arms and are best fit with a power-law slope of alpha = -1.96+/-0.15. We assign arm/interarm status for HII regions based upon the varying surface brightness of diffuse emission as a function of position throughout the image. Using our measurement of the integrated flux contributed by resolved HII regions in M51, we estimate the diffuse fraction to be approximately 0.45 -- in agreement with the determination of Greenawalt et al. (1998). Automated processing of degraded datasets is undertaken to gauge systematic effects associated with limiting spatial resolution and sensitivity.

David A. Thilker; Robert Braun; Rene A. M. Walterbos

2000-06-01

372

A SEARCH FOR THE TRANSIT OF HD 168443b: IMPROVED ORBITAL PARAMETERS AND PHOTOMETRY  

SciTech Connect

The discovery of transiting planets around bright stars holds the potential to greatly enhance our understanding of planetary atmospheres. In this work we present the search for transits of HD 168443b, a massive planet orbiting the bright star HD 168443 (V = 6.92) with a period of 58.11 days. The high eccentricity of the planetary orbit (e = 0.53) significantly enhances the a priori transit probability beyond that expected for a circular orbit, making HD 168443 a candidate for our ongoing Transit Ephemeris Refinement and Monitoring Survey. Using additional radial velocities from Keck High Resolution Echelle Spectrometer, we refined the orbital parameters of this multi-planet system and derived a new transit ephemeris for HD 168443b. The reduced uncertainties in the transit window make a photometric transit search practicable. Photometric observations acquired during predicted transit windows were obtained on three nights. Cerro Tololo Inter-American Observatory 1.0 m photometry acquired on 2010 September 7 had the required precision to detect a transit but fell just outside of our final transit window. Nightly photometry from the T8 0.8 m automated photometric telescope at Fairborn Observatory, acquired over a span of 109 nights, demonstrates that HD 168443 is constant on a timescale of weeks. Higher-cadence photometry on 2011 April 28 and June 25 shows no evidence of a transit. We are able to rule out a non-grazing transit of HD 168443b.

Pilyavsky, Genady; Mahadevan, Suvrath; Wright, Jason T.; Wang, Xuesong X. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Kane, Stephen R.; Ciardi, David R.; Dragomir, Diana; Von Braun, Kaspar [NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Howard, Andrew W. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); De Pree, Chris; Marlowe, Hannah [Department of Physics and Astronomy, Agnes Scott College, 141 East College Avenue, Decatur, GA 30030 (United States); Fischer, Debra [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States); Jensen, Eric L. N. [Department of Physics and Astronomy, Swarthmore College, Swarthmore, PA 19081 (United States); Laughlin, Gregory [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Rabus, Markus, E-mail: gcp5017@psu.edu, E-mail: suvrath@astro.psu.edu [Departamento de Astonomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)

2011-12-20

373

Near-infrared photometry of Y dwarfs: low ammonia abundance and the onset of water clouds  

E-print Network

We present new near-infrared photometry for seven late-type T dwarfs and nine Y-type dwarfs, and lower limit magnitudes for a tenth Y dwarf, obtained at Gemini Observatory. We also present a reanalysis of H-band imaging data from the Keck Observatory Archive, for an eleventh Y dwarf. These data are combined with earlier MKO-system photometry, Spitzer and WISE mid-infrared photometry, and available trigonometric parallaxes, to create a sample of late-type brown dwarfs which includes ten T9-T9.5 dwarfs or dwarf systems, and sixteen Y dwarfs. We compare the data to our models which include updated H_2 and NH_3 opacity, as well as low-temperature condensate clouds. The models qualitatively reproduce the trends seen in the observed colors, however there are discrepancies of around a factor of two in flux for the Y0-Y1 dwarfs, with T_eff~350-400K. At T_eff~400K, the problems could be addressed by significantly reducing the NH_3 absorption, for example by halving the abundance of NH_3 possibly by vertical mixing. At...

Leggett, S K; Marley, M S; Saumon, D

2014-01-01

374

Spectral photometry of extreme helium stars: Ultraviolet fluxes and effective temperature  

NASA Technical Reports Server (NTRS)

Ultraviolet flux distributions are presented for the extremely helium rich stars BD +10 deg 2179, HD 124448, LSS 3378, BD -9 deg 4395, LSE 78, HD 160641, LSIV -1 deg 2, BD 1 deg 3438, HD 168476, MV Sgr, LS IV-14 deg 109 (CD -35 deg 11760), LSII +33 deg 5 and BD +1 deg 4381 (LSIV +2 deg 13) obtained with the International Ultraviolet Explorer (IUE). Broad band photometry and a newly computed grid of line blanketed model atmospheres were used to determine accurate angular diameters and total stellar fluxes. The resultant effective temperatures are in most cases in satisfactory agreement with those based on broad band photometry and/or high resolution spectroscopy in the visible. For two objects, LSII +33 deg 5 and LSE 78, disagreement was found between the IUE observations and broadband photometry: the colors predict temperatures around 20,000 K, whereas the UV spectra indicate much lower photospheric temperatures of 14,000 to 15,000 K. The new temperature scale for extreme helium stars extends to lower effective temperatures than that of Heber and Schoenberner (1981) and covers the range from 8,500 K to 32,000 K.

Drilling, J. S.; Schoenberner, D.; Heber, U.; Lynas-Gray, A. E.

1982-01-01

375

High quality optical photometry of NEOs in support of a Warm Spitzer program  

NASA Astrophysics Data System (ADS)

Near Earth Objects (NEOs) may act as dynamical and compositional tracers of the history of near-Earth space. However, despite their scientific importance, key characteristics of the NEO population - such as the size distribution, mix of albedos and mineralogies, and contributions from so-called dead or dormant comets - remain largely unexplored; some 99% of all presently known NEOs are essentially uncharacterized. We have been awarded 500 hours of Warm Spitzer time to study ~700 NEOs. The Spitzer data will allow us to measure thermal fluxes and, in combination with optical data, derive albedos and diameters for a large fraction of all known NEOs. The primary uncertainty in our Spitzer results will derive from a lack of good optical photometry for our targets. We propose here a tightly focused program to obtain optical photometry of ~100 NEOs with a range of telescopes. These observations have been carefully planned to maximize efficiency and minimize demand on the largest telescopes, and are complemented by observations obtained elsewhere. The resulting photometry will enable our Warm Spitzer NEO science.

Trilling, David E.; Thomas, Cristina A.; Hora, Joseph L.; Penprase, Bryan; Emery, Joshua P.; Kistler, John L.; Spahr, Timothy B.

2010-02-01

376

A Recalibration of Optical Photometry: Tycho-2, Strömgren, and Johnson Systems  

NASA Astrophysics Data System (ADS)

I use high-quality Hubble Space Telescope (HST) spectrophotometry to analyze the calibration of three popular optical photometry systems: Tycho-2 BT and VT, Strömgren uvby, and Johnson UBV. For Tycho-2, I revisit the analysis of an earlier paper to include the new recalibration of grating/aperture corrections, vignetting, and charge transfer inefficiency effects produced by the Space Telescope Imaging Spectrograph group and to consider the consequences of both random and systematic uncertainties. The new results reaffirm the good quality of both the Tycho-2 photometry and the HST spectrophotometry but yield a slightly different value for ZPBT-VT of 0.033+/-0.001 (random) +/-0.005 (systematic) mag. For the Strömgren v, b, and y filters I find that the published sensitivity curves are consistent with the available photometry and spectrophotometry, and I derive new values for the associated ZPb-y and ZPm1. The same conclusion is drawn for the Johnson B and V filters and the associated ZPB-V. The situation is different for the Strömgren u and the Johnson U filters. There I find that the published sensitivity curves yield results that are inconsistent with the available photometry and spectrophotometry, likely caused by an incorrect treatment of atmospheric effects on the short-wavelength end. I reanalyze the data to produce new average sensitivity curves for those two filters and new values for ZPc1 and ZPU-B. The new computation of synthetic U-B and B-V colors uses a single B sensitivity curve, which eliminates the previous unphysical existence of different definitions for each color. Finally, I find that if one uses values from the literature for which uncertainties are not given, reasonable estimates for these are 1%-2% for Strömgren b-y, m1, and c1 and 2%-3% for Johnson B-V and U-B. The use of the results in this paper should lead to a significant reduction of systematic errors when comparing synthetic photometry models with real colors and indices.

Maíz Apellániz, J.

2006-02-01

377

High-temperature measurement techniques for the application in photometry, radiometry and thermometry  

NASA Astrophysics Data System (ADS)

Well characterised sources of thermal radiation are essential for photometry, radiometry, and thermometry. They serve as reference radiators for the calibration of detectors and radiance sources. Thermal radiation sources are advantageous for this purpose compared to other radiance sources such as lamps or LEDs because they possess a continuous spectrum of the emitted spectral radiance, which, for blackbody sources, can be calculated analytically using Planck’s law of radiation. For application in thermometry, blackbody sources starting from temperatures near absolute zero to temperatures up to 3000 ?C are needed for the calibration of radiation thermometers. For application in photometry and radiometry high intensity sources of radiation in the visible and UV region of the optical spectrum were required. This latter requirement is met by blackbody sources at temperatures well above 2000 ?C. An ideal reference source should always emit the same amount of radiation at any time of use. This is realised by fixed-point radiators. Such radiators are based on a phase transition of a substance, at high temperatures the melting and freezing points of metals. However, current metal fixed-points are limited to relatively low temperatures. In the present work innovative techniques necessary for research into high-temperature thermal radiation sources are developed and thoroughly described. Starting with variable temperature blackbody sources the techniques required are: Precise apertures determination and detailed characterisation of the applied optical detectors. The described techniques are then used to undertake research into the development of high-temperature fixed-points above the copper fixed-point for application in photometry, radiometry, and thermometry. Applying these sophisticated techniques it was shown that these new high-temperature fixed-points are reproducible and repeatable to better than 100 mK at temperatures up to nearly 3200 K. Finally, a forward look is given that shows the potential of such fixed-points for improving traceability and accuracy in photometry, radiometry, and thermometry. This work forms the foundation for accurate and practical applications of high-temperature fixed-point sources and sets the international benchmark for measurement techniques in photometry, radiometry, and thermometry. This work will open the use of the novel high-temperature fixed-points in an improved International Temperature Scale and will significantly improve and ease the realisation and dissemination of the SI base unit candela, significantly reducing the uncertainty for industrial measurements in these fields.

Hartmann, Jürgen

2009-01-01

378

VizieR Online Data Catalog: Multiwavelength photometry for 34 SMGs (Rowlands+, 2014)  

NASA Astrophysics Data System (ADS)

Photometry for 34 submillimetre galaxies (including 5 galaxies with poor quality SED fits rejected from the final sample) utilised in the paper from the compilation in Magnelli et al (2012A&A...539A.155M, hereafter M12), which were taken from blank field (sub)millimetre surveys (850-1200um) which have robust counterparts identified with deep radio, interferometric submillimetre and/or mid-infrared imaging. In GOODS-N all photometry shortwards of 3um is described in Berta et al. (2010A&A...518L..30B, 2011A&A...532A..49B) and includes PSF-matched photometry from HST ACS bviz (version 1.0), FLAMINGOS JHK, IRAC 3.6, 4.5, 5.8, 8.0um was obtained with the ConvPhot code and spectroscopic redshifts and U-band magnitudes from Barger et al. (2008, Cat. J/ApJ/689/687). Deep CFHT WirCAM K_s band photometry was taken from Wang et al. (2010, Cat. J/ApJS/187/251). We refer the reader to http://www2011.mpe.mpg.de/ir/Research/PEP/publicdatareleases.php?lang=en for details, but briefly, magnitudes with value +99.99 are non-detections. ConvPhot-derived magnitudes are negative if they are fainter than the 1-sigma noise level. In this case the absolute value of the magnitude (with a small correction to galactic extinction) corresponds to half their flux and their magnitude uncertainty is equal to 0.7526mag. The U-band magnitudes from Barger et al. (2008, Cat. J/ApJ/689/687) are -99.99 if a source was not matched. In some cases magnitudes are negative and not -99.99, see Barger et al (2008, Cat. J/ApJ/689/687) for details. WIRCam Ks magnitudes are -99.99 if an object was not matched. The 70um MIPS data in GOODS-N are from Magnelli et al. (2011, Cat. J/A+A/528/A35), negative flux values indicate an upper limit, with the absolute flux value equal to the 5? upper limit computed from the 70um residual map. We list the uncertainties from both the residual map and Monte-Carlo simulations which includes an additional statistical contribution from confusion noise, see Magnelli et al. (2011, Cat J/A+A/528/A35) for details. In ECDFS we use the compilation of photometry for SMGs presented in Wardlow et al. (2011, Cat. J/MNRAS/415/1479) which includes data from MUSYC (Gawiser et al. 2006, Cat. J/ApJS/162/1), Taylor et al. (2009, Cat. J/ApJS/183/295), IRAC photometry from Damen et al. (2011, cat. J/ApJ/727/1) and GOODS/VIMOS U-band data from Nonino et al. (2009 2009ApJS..183..244N). Non-detections with a 3 sigma upper limit flag in Wardlow et al. (2011, Cat. J/MNRAS/415/1479) are indicated by a negative value of the catalogue magnitude after correcting for galactic extinction. The 70um Herschel PACS data is from Magnelli et al. (2012A&A...539A.155M.). In the Lockman Hole we use the photometry described in Fotopoulou et al. (2012, Cat. J/ApJS/198/1), which comprises UV data from GALEX, Large Binocular Telescope (U, B, V, Y, z') and Subaru (Rc, Ic, z') photometry, J and K photometry from the UKIRT and MIR data from IRAC. We present the catalogue magnitudes without the zeropoint offsets applied so that the user can choose whether to apply them. A value of -99 indicates that a value of 99 was produced by SExtractor for either the magnitude or the error, or the source was has no coverage in that band. In the COSMOS field we use the Intermediate and Broad Band Photometry Catalog as presented in Capak et al. (2007, Cat. II/284), Ilbert et al. (2009ApJ...690.1236I) Salvato et al. (2009ApJ...690.1250S) and McCracken et al (2010ApJ...708..202M). We have applied the offsets in the catalogue to correct the magnitudes to total , but we leave the choice of applying zeropoint offsets up to the user. Magnitudes with value of 99 indicate a non-detection, with the error equal to the 1 sigma limiting magnitude (not corrected to total or galactic extinction corrected). See also Salvato et al. (2009ApJ...690.1250S) and Elvis et al. (2012ApJ...759....6E) for 5 sigma catalogue depths. The public Spitzer IRAC photometry was retrieved from the COSMOS archive (http://irsa.ipac.caltech.edu/data/COSMOS/). The 1.9" aperture fluxes have been corrected to total us

Rowlands, K.; Dunne, L.; Dye, S.; Aragon-Salamanca, A.; Maddox, S.; da Cunha, E.; Smith, D. J. B.; Bourne, N.; Eales, S.; Gomez, H. L.; Smail, I.; Alpaslan, M.; Clark, C. J. R.; Driver, S.; Ibar, E.; Ivison, R. J.; Robotham, A.; Smith, M. W. L.; Valiante, E.

2014-03-01

379

Retrieval of optical depth and particle size distribution of tropospheric and stratospheric aerosols by means of sun photometry  

SciTech Connect

Aerosol optical depth measurements by means of ground-based Sun photometry were made in Bern, Switzerland during two and a half years primarily to provide quantitative corrections for atmospheric effects in remotely sensed data in the visible and near-infrared spectral region. An investigation of the spatial variability of tropospheric aerosol was accomplished in the summer of 1994 in the Swiss Central Plain, a region often covered by a thick aerosol layer. Intercomparisons are made with two Sun photometers operated by the Swiss Meteorological Institute in Payerne and Davos. By means of an inversion technique, columnar particle size distributions were derived from the aerosol optical depth spectra. Effective radius, columnar surface area, and columnar mass were computed from the inversion results. Most of the spectra measured in Bern exhibit an Angstroem-law dependence. Consequently, the inverted size distributions are very close to power-law distributions. Data collected during a four month calibration campaign in fall 1993 at a high-mountain station in the Swiss Alps allowed the authors to study optical properties of stratospheric aerosol. The extinction spectra measured have shown to be still strongly influenced by remaining aerosol of the June 1991 volcanic eruptions of Mount Pinatubo. Inverted particle size distributions can be characterized by a broad monodisperse peak with a mode radius around 0.25 {micro}m. Both aerosol optical depths and effective radii had not yet returned to pre-eruption values. Comparison of retrieved aerosol optical depth, columnar surface area and mass, with the values derived from lidar observations performed in Garmisch-Partenkirchen, Southern-Germany, yielded good agreement.

Schmid, B.; Maetzler, C.; Kaempfer, N. [Univ. of Bern (Switzerland). Inst. of Applied Physics] [Univ. of Bern (Switzerland). Inst. of Applied Physics; Heimo, A. [Swiss Meteorological Inst., Payerne (Switzerland)] [Swiss Meteorological Inst., Payerne (Switzerland)

1997-01-01

380

Variables Affecting Earth's Albedo  

NSDL National Science Digital Library

Earth's albedo is the fraction of incoming radiation (sunlight) that is reflected into space. The Earth has an average albedo, which describes how much sunlight is reflected on average for the whole planet and the whole year. The Earth also has a local albedo, which determines how much of the Sun's light is reflected from a particular place at a particular time. The local albedo depends on the particular local surface, which can change seasonally as vegetation changes. It also depends on more rapidly changing things such as snow and clouds. In this lesson, students will investigate one of the variables that affect the Earth's albedo. They will collect and graph data on Earth's albedo from two surface types at the same latitude over a period of two years. They will then use the data to calculate how much difference there is in Earth's albedo between the two locations and suggest reasons for the differences.

381

HK photometry in an UCHII region near Sh2-217 (Brand+, 2011)  

NASA Astrophysics Data System (ADS)

Coordinates and photometric parameters (magnitudes and colours) are presented of the stars located in a molecular condensation on the SW-border of the Galactic HII region Sh2-217. The data were obtained on January 4, 2004 with the 3.58-m Telescopio Nazionale Galileo (TNG; La Palma, Canary Islands, Spain). Near-infrared observations were carried out through H and K' broad-band filters with the camera NICS. The image scale is 0.25arcsec/pixel, yielding a field of view of about 4.2'x4.2'. Observing strategy and exposure times are described in Deharveng et al. (2006A&A...458..191D), the only difference being that the dithering sequence for the H-band images was the same as adopted for K'. The data reduction steps adopted are outlined in Deharveng et al. (2006A&A...458..191D). Aperture photometry was done using the DAOPHOT package in IRAF. We followed the same procedure described in Deharveng et al. (2006A&A...458..191D) to obtain aperture photometry, after which PSF-fitting photometry was performed. Although the seeing was good (<1"), the night was barely photometric, so we calibrated our H, K' photometry with that performed on the same field by Deharveng et al. (2003, Cat. J/A+A/399/1135). We calculated the difference in magnitudes for each coinciding source and plotted it against our derived instrumental H-K'. A colour term was present in K' because of the difference between the K and K' filters. After a best-fit calibration, a residual r.m.s. of about 0.2mag. was present in the difference between our photometry and that of Deharveng et al. (2003, J/A+A/399/1135), probably because of the different seeing and possibly also due to the intrinsic variability of young stars. Our photometry is thus on the same HK standard system as Deharveng et al. (2003, J/A+A/399/1135). Sources with K, H < 11-12 are in the non-linear regime or saturated, but such bright objects are few in number and lie outside the cluster, and are probably foreground stars. The approximate limiting magnitudes are K=18.48 and H=19.52, much deeper than achieved by Deharveng et al. (2003, J/A+A/399/1135). We estimate completeness limits of approximately K=16.5 and H=17.5 from the peak in histograms of the number of detected sources as a function of magnitude, after binning in 1mag. intervals. The astrometric calibration of the frames was obtained by measuring the position on the image of a sample of stars and fitting those positions to the equatorial coordinates given by Deharveng et al. (2006A&A...458..191D), using tasks of STSDAS/IRAF. The typical accuracy of this procedure is of the order of 1". (1 data file).

Brand, J.; Massi, F.; Zavagno, A.; Deharveng, L.; Lefloch, B.

2010-11-01

382

Diagnostic potential of endotoxin scattering photometry for sepsis and septic shock.  

PubMed

Endotoxin scattering photometry (ESP) is a novel Limulus amebocyte lysate (LAL) assay that uses a laser light-scattering particle-counting method. In the present study, we compared ESP, standard turbidimetric LAL assay, and procalcitonin assay for the evaluation of sepsis after emergency gastrointestinal surgery. A total of 174 samples were collected from 40 adult patients undergoing emergency gastrointestinal surgery and 10 patients with colorectal cancer undergoing elective surgery as nonseptic controls. Plasma endotoxin levels were measured with ESP and turbidimetric LAL assay, and plasma procalcitonin levels were assessed with a standard procalcitonin assay. Plasma endotoxin and procalcitonin levels increased corresponding to the degree of sepsis. Endotoxin scattering photometry significantly discriminated between patients with or without septic shock: sensitivity, 81.1%; specificity, 76.6%; positive predictive value, 48.4%; negative predictive value, 93.8%; and accuracy, 77.6%. The area under the receiver operating characteristic curve for septic shock with the ESP assay (endotoxin cutoff value, 23.8 pg/mL) was 0.8532 ± 0.0301 (95% confidence interval, 0.7841-0.9030; P < 0.0001). The predictive power of ESP was superior to that of turbidimetric assay (difference, 0.1965 ± 0.0588; 95% confidence interval, 0.0812-0.3117; P = 0.0008). There was no significant difference in predictive power between ESP and procalcitonin assay. Endotoxin scattering photometry also discriminated between patients with and without sepsis. Area under the receiver operating characteristic curve analysis showed that ESP had the best predictive power for diagnosing sepsis. In conclusion, compared with turbidimetric LAL assay, ESP more sensitively detected plasma endotoxin and significantly discriminated between sepsis and septic shock in patients undergoing gastrointestinal emergency surgery. PMID:24089007

Shimizu, Tomoharu; Obata, Toru; Sonoda, Hiromichi; Akabori, Hiroya; Miyake, Tohru; Yamamoto, Hiroshi; Tabata, Takahisa; Eguchi, Yutaka; Tani, Tohru

2013-12-01

383

Weighing the Giants - II. Improved calibration of photometry from stellar colours and accurate photometric redshifts  

NASA Astrophysics Data System (ADS)

We present improved methods for using stars found in astronomical exposures to calibrate both star and galaxy colours as well as to adjust the instrument flat-field. By developing a spectroscopic model for the Sloan Digital Sky Survey (SDSS) stellar locus in colour-colour space, synthesizing an expected stellar locus, and simultaneously solving for all unknown zero-points when fitting to the instrumental locus, we increase the calibration accuracy of stellar locus matching. We also use a new combined technique to estimate improved flat-field models for the Subaru SuprimeCam camera, forming `star flats' based on the magnitudes of stars observed in multiple positions or through comparison with available measurements in the SDSS catalogue. These techniques yield galaxy magnitudes with reliable colour calibration (?0.01-0.02 mag accuracy) that enable us to estimate photometric redshift probability distributions without spectroscopic training samples. We test the accuracy of our photometric redshifts using spectroscopic redshifts zs for ˜5000 galaxies in 27cluster fields with at least five bands of photometry, as well as galaxies in the Cosmic Evolution Survey (COSMOS) field, finding ?((zp - zs)/(1 + zs)) ? 0.03 for the most probable redshift zp. We show that the full posterior probability distributions for the redshifts of galaxies with five-band photometry exhibit good agreement with redshifts estimated from thirty-band photometry in the COSMOS field. The growth of shear with increasing distance behind each galaxy cluster shows the expected redshift-distance relation for a flat ? cold dark matter (?-CDM) cosmology. Photometric redshifts and calibrated colours are used in subsequent papers to measure the masses of 51 galaxy clusters from their weak gravitational shear and determine improved cosmological constraints. We make our PYTHON code for stellar locus matching publicly available at http://big-macs-calibrate.googlecode.com; the code requires only input catalogues and filter transmission functions.

Kelly, Patrick L.; von der Linden, Anja; Applegate, Douglas E.; Allen, Mark T.; Allen, Steven W.; Burchat, Patricia R.; Burke, David L.; Ebeling, Harald; Capak, Peter; Czoske, Oliver; Donovan, David; Mantz, Adam; Morris, R. Glenn

2014-03-01

384

Using Narrow Band Photometry to Detect Young Brown Dwarfs in IC348  

E-print Network

We report the discovery of a population of young brown dwarf candidates in the open star cluster IC348 and the development of a new spectroscopic classification technique using narrow band photometry. Observations were made using FLITECAM, the First Light Camera for SOFIA, at the 3-m Shane Telescope at Lick Observatory. FLITECAM is a new 1-5 micron camera with an 8 arcmin field of view. Custom narrow band filters were developed to detect absorption features of water vapor (at 1.495 microns) and methane (at 1.66 microns) characteristic of brown dwarfs. These filters enable spectral classification of stars and brown dwarfs without spectroscopy. FLITECAM's narrow and broadband photometry was verified by examining the color-color and color-magnitude characteristics of stars whose spectral type and reddening was known from previous surveys. Using our narrow band filter photometry method, it was possible to identify an object measured with a signal-to-noise ratio of 20 or better to within +/-3 spectral class subtypes for late-type stars. With this technique, very deep images of the central region of IC348 (H ~ 20.0) have identified 18 sources as possible L or T dwarf candidates. Out of these 18, we expect that between 3 - 6 of these objects are statistically likely to be background stars, with the remainder being true low-mass members of the cluster. If confirmed as cluster members then these are very low-mass objects (~5 Mjupiter). We also describe how two additional narrow band filters can improve the contrast between M, L, and T dwarfs as well as provide a means to determine the reddening of an individual object.

A. K. Mainzer; Ian S. McLean

2003-06-30

385

An Updated Catalog of M31 Globular-like Clusters: UBVRI Photometry, Ages, and Masses  

NASA Astrophysics Data System (ADS)

We present an updated UBVRI photometric catalog containing 970 objects in the field of M31, selected from the Revised Bologna Catalog (RBC v.4.0), including 965, 967, 965, 953, and 827 sources in the individual UBVRI bands, respectively, of which 205, 123, 14, 126, and 109 objects do not have previously published photometry. Photometry is performed using archival images from the Local Group Galaxies Survey, which covers 2.2 deg2 along the major axis of M31. Detailed comparisons show that our photometry is fully consistent with previous measurements in all filters. We focus on 445 confirmed "globular-like" clusters and candidates, comprising typical globular and young massive clusters. The ages and masses of these objects are derived by comparing their observed spectral-energy distributions with simple stellar population synthesis. Approximately half of the clusters are younger than 2 Gyr, suggesting that there has been significant recent active star formation in M31, which is consistent with previous results. We note that clusters in the halo (r projected > 30 kpc) are composed of two different components: older clusters with ages >10 Gyr and younger clusters with ages around 1 Gyr. The spatial distributions show that the young clusters (<2 Gyr) are spatially coincident with the galaxy's disk, including the "10 kpc ring," the "outer ring," and the halo of M31, while the old clusters (>2 Gyr) are spatially correlated with the bulge and halo. We also estimate the masses of the 445 confirmed clusters and candidates in M31 and find that our estimates agree well with previously published values. We find that none of the young disk clusters can survive the inevitable encounters with giant molecular clouds in the galaxy's disk and that they will eventually be disrupted on timescales of a few Gyr. Specifically, young disk clusters with a mass of 104 M sun are expected to dissolve within 3.0 Gyr and will, thus, not evolve to become globular clusters.

Fan, Zhou; de Grijs, Richard; Zhou, Xu

2010-12-01

386

VizieR Online Data Catalog: King 5 and Berkeley 20 UBVRI photometry (Durgapal+, 2001)  

NASA Astrophysics Data System (ADS)

We present multicolour CCD photometry for two poorly studied open clusters (King 5 and Be 20). Photometry for a field near King 5 was also carried out to estimate the contamination by field stars. The colour magnitude diagrams (CMD) of the clusters show a well defined main sequence extending to the limit of the photometry, V~=20mag. The reddening for King 5, estimated from the colour-colour diagram, is ~0.82, whereas that for Be 20 as estimated by comparing theoretical main-sequence (MS) with the observed MS is 0.10. The morphology of the CMDs indicates that these clusters are old. The CMD of Be 20 shows a globular cluster-like horizontal branch. In case of King 5 the comparison of observational CMDs with the standard isochrones of VandenBerg (1985ApJS...58..711V) indicates an apparent discrepancy between the shape of the turnoff and isochrones. The CMDs of King 5 seem to be better understood in terms of stellar models with convective overshoot. The comparison of the CMDs with the stellar models by Bertelli et al. (1985A&A...150...33B) with convective overshoot produces a good fit for a metallicity Z=0.008 and an age of 1Gyr for King 5 and 5Gyr for Be 20. An apparent distance modulus (m-M)=14.0 and 15.1 has been estimated for King 5 and Be 20 respectively. They correspond to a distance of 1900+/-100pc and 9026+/-480pc, respectively. The radial density distribution in King 5 indicates that there is an excess of low mass stars in the outer region of the cluster, whereas the density distribution in Be 20 shows a good fit with the empirical King (1962AJ.....67..471K) model. For both clusters, observations have also been carried out to search for variable stars. (3 data files).

Durgapal, A. K.; Pandey, A. K.; Mohan, V.

2001-05-01

387

DEEP, WIDE-FIELD CCD PHOTOMETRY FOR THE OPEN CLUSTER NGC 3532  

SciTech Connect

We present the results of a deep, wide-field CCD survey for the open cluster NGC 3532. Our new BV(RI){sub c} photometry effectively covers a one square degree area and reaches an unprecedented depth of V {approx} 21 to reveal that NGC 3532 is a rich open cluster that harbors a large number of faint, low-mass stars. We employ a number of methods to reduce the impact of field star contamination in the cluster color-magnitude diagrams (CMDs), including supplementing our photometry with JHK{sub s} data from the 2MASS catalog. These efforts allow us to define a robust sample of candidate main-sequence stars suitable for a purely empirical determination of the cluster's parameters by comparing them to the well-established Hyades main sequence. Our results confirm previous findings that NGC 3532 lies fairly near to the Sun [(m - M){sub 0} = 8.46 {+-} 0.05; 492{sup +12}{sub -11} pc] and has an extremely low reddening for its location near the Galactic plane [E(B - V) = 0.028 {+-} 0.006]. Moreover, an age of {approx}300 Myr has been derived for the cluster by fitting a set of overshooting isochrones to the well-populated upper main sequence. This new photometry also extends faint enough to reach the cluster white dwarf sequence, as confirmed by our photometric recovery of eight spectroscopically identified members of the cluster. Using the location of these eight members, along with the latest theoretical cooling tracks, we have identified {approx}30 additional white dwarf stars in the [V, (B - V)] CMD that have a high probability of belonging to NGC 3532. Reassuringly, the age we derive from fitting white dwarf isochrones to the locus of these stars, 300 {+-} 100 Myr, is consistent with the age derived from the turnoff. Our analysis of the photometry also includes an estimation of the binary star fraction as well as a determination of the cluster's luminosity and mass functions.

Clem, James L.; Landolt, Arlo U. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001 (United States); Hoard, D. W.; Wachter, Stefanie, E-mail: jclem@phys.lsu.edu, E-mail: landolt@phys.lsu.edu, E-mail: hoard@ipac.caltech.edu, E-mail: wachter@ipac.caltech.edu [Spitzer Science Center, California Institute of Technology, 1200 E. California Blvd., MC 220-6, Pasadena, CA 91125 (United States)

2011-04-15

388

Dwarf Irregular Galaxy Leo A: Suprime-Cam Wide-field Stellar Photometry  

NASA Astrophysics Data System (ADS)

We have surveyed a complete extent of Leo A—an apparently isolated gas-rich low-mass dwarf irregular galaxy in the Local Group. The B, V, and I passband CCD images (typical seeing ~0.''8) were obtained with the Subaru Telescope equipped with the Suprime-Cam mosaic camera. The wide-field (20' × 24') photometry catalog of 38,856 objects (V ~ 16-26 mag) is presented. This survey is also intended to serve as "a finding chart" for future imaging and spectroscopic observation programs of Leo A. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

Stonkut?, Rima; Arimoto, Nobuo; Hasegawa, Takashi; Narbutis, Donatas; Tamura, Naoyuki; Vansevi?ius, Vladas

2014-10-01

389

H-alpha Confirmation, Astrometry and Photometry of Two Novae in M31  

NASA Astrophysics Data System (ADS)

We obtained five 120-s narrow-band H-alpha and three 90-s R-band CCD frames of the central region of M31 on 2013 June 27.189 and 27.193 UT, respectively, with the 2.5-m Isaac Newton Telescope + WFC at La Palma under ~2.0" seeing. The single frames were co-added and the co-added images were used for photometry and astrometry of the two recently discovered and spectroscopically unconfirmed M31 nova candidates, namely the PNV J00424894+4115163 (ATel #5133) and PNV J00425987+4120379 (ATel #5157).

Hornoch, K.; Vaduvescu, O.; Gonzalez, A.

2013-06-01

390

EMCCD Speckle Measurements, Differential Photometry and Dynamical Masses of Visual Binary Stars  

NASA Astrophysics Data System (ADS)

We report results of the EMCCD speckle measurements and differential photometry conducted for 46 visual binaries with the 6 m telescope of SAO (Russia) in 2007. The orbits for COU 1281 and COU 1037 are calculated for the first time and those for CHA 137, COU 100, COU 1136, CHA 51, CHA 55, COU 206, ADS 13961 are improved. Using dynamical parallax, both distance and total mass estimates for these pairs were obtained. In general, dynamical parallaxes and total masses are in good agreement with Hipparcos data and standard mass-luminosity calibrations respectively.

Tamazian, V. S.; Docobo, J. A.; Balega, Yu. Yu.; Melikian, N. D.; Malogolovets, E. A.

2011-07-01

391

VizieR Online Data Catalog: Differential photometry of FK Com (Korhonen+, 2007)  

NASA Astrophysics Data System (ADS)

In the present work we publish new photometric observations of the very active single giant, FK Com for the time period between the 1st of January 2002 and the 8th of July 2004. The observations have been carried out with three different automatic photometric telescopes: Phoenix 10, Wolfgang and Amadeus, all located in Arizona, USA. Observations contain measurements at the following bands: Johnson U, B and V, Cousins I and Stroemgren b and y. The observations are differential photometry in respect to the primary comparison star HD 117567. (3 data files).

Korhonen, H.; Berdyugina, S. V.; Hackman, T.; Ilyin, I. V.; Strassmeier, K. G.; Tuominen, I.

2007-10-01

392

VizieR Online Data Catalog: BVI photometry of 5 CVn cloud galaxies (Karachentsev+ 1998)  

NASA Astrophysics Data System (ADS)

We present results of CCD imaging in B, V of five late-type galaxies with radial velocities V0<350km/s in the Canes Venatici cloud. Based on the photometry of their brightest blue stars we derived the following distances to the galaxies: 9.7Mpc for NGC 4144, 4.5Mpc for NGC 4244, 4.2Mpc for NGC 4395, 2.9Mpc for NGC 4449, and 8.2Mpc for UGC 8331. (1 data file).

Karachentsev, I. D.; Drozdovsky, I. O.

1998-01-01

393

Follow-up of Kepler candidates transiting hot-Jupiter with ground based photometry  

NASA Astrophysics Data System (ADS)

We have selected a group of planetary candidates from the Kepler field with short transiting times and observed them at the West Mountain Observatory (WMO) with the objective to confirm or find their nature. The resulting light curves showed that KOI667 is a diluted eclipsing binary. Further observations at the Dominion Astrophysical Observatory (DAO) and the use of Point Spread Function (PSF) photometry resolved the eclipsing binary. We present the techniques used to obtain the light curves and the identification of the eclipsing binary.

Gaillard, Clement; Stephens, D.; Larson, J.; Ranquist, E.; Stoker, E.; Rawlins, J.

2013-10-01

394

Dwarf Irregular Galaxy Leo A. Suprime-Cam Wide-Field Stellar Photometry  

E-print Network

We have surveyed a complete extent of Leo A - an apparently isolated gas-rich low-mass dwarf irregular galaxy in the Local Group. The $B$, $V$, and $I$ passband CCD images (typical seeing $\\sim$0.8") were obtained with Subaru Telescope equipped with Suprime-Cam mosaic camera. The wide-field ($20' \\times 24'$) photometry catalog of 38,856 objects ($V \\sim 16-26$ mag) is presented. This survey is also intended to serve as "a finding chart" for future imaging and spectroscopic observation programs of Leo A.

Stonkut?, R; Hasegawa, T; Narbutis, D; Tamura, N; Vansevi?ius, V

2014-01-01

395

UvbyH-beta photoelectric and CCD photometry of IC 4651  

Microsoft Academic Search

uvbyHbeta photoelectric and CCD photometry of the old, open southern cluster IC 4651 is presented and analyzed. The combined data lead to the following cluster characteristics: E(b-y) = 0.064±0.006, [Fe\\/H] = +0.23±0.02, (m-M)0 = 9.83±0.04, and an age on the system of VandenBerg (1985) of 2.4±0.2×109yr. The cluster color-magnitude diagram exhibits some scatter, all of which can be explained by

Barbara J. Anthony-Twarog; Bruce A. Twarog

1987-01-01

396

CCD photometry of asteroids 970 Primula and 1631 Kopff using a remote commercial telescope  

NASA Astrophysics Data System (ADS)

CCD photometry of asteroids 970 Primula and 1631 Kopff obtained remotely at Tenagra Observatories during October and November 2003 is reported. A synodic rotation period of 2.777±0.001 hours is determined from four nights of observations for Primula. The resulting rotation period for Kopff is 6.683±0.001 hours from five nights of observations. Both observed lightcurves were nearly symmtrical with amplitudes of 0.18±0.02 magnitudes for Primula and 0.41±0.04 for Kopff.

Sada, Pedro V.; Canizales, Eder D.; Armada, Edgar M.

2004-09-01

397

Kinematics and photometry as complementary tools in the study of barred galaxies  

E-print Network

Recent advances in observational techniques and theoretical modelling of galaxy kinematics allow us to use more than just optical morphology to discern the structure and dynamics of galaxies. Here, we show for three barred galaxies (UGC 10205, NGC 6221 and NGC4340) that both kinematics and photometry are necessary to fully understand the properties of these galaxies. Kinematic and spectrophotometric data enable us to detect structures such as bars and gas shocks that are not directly visible in the images; conversely, imaging can be crucial for understanding the kinematic and dynamical behavior of a galaxy.

Juan Carlos Vega Beltran; Peter Erwin; John Beckman; Alessandro Pizzella; Enrico Maria Corsini; Francesco Bertola; Werner W. Zeilinger

2000-10-30

398

Empirical Calibration of Hubble Space Telescope WFPC2 F606W and F814W Photometry  

E-print Network

Using the ground-based V and I photometry of a sample of stars from the Groth Strip, we obtain the first empirical calibration of the F606W and F814W Hubble Space Telescope WFPC2 filters for 0.5

Samir Salim; Andrew Gould

1998-09-30

399

Mode identification for Balloon 090100001 using combined multicolour photometry and spectroscopy  

E-print Network

In this paper, we show that method of mode identification using combined multicolour photometry and spectroscopy can be successfully applied to the pulsating subdwarf B star Balloon 090100001. The method constrains the spherical degree, l.We confirm that the dominant mode is radial and we show that for some other modes the method provides values of l consistent with the observed rotationally split triplet. Moreover, we derive a radius variation of 1.7 per cent for the dominant mode. The identification opens the possibility for constraining the internal structure of the star by means of seismic methods.

A. Baran; A. Pigulski; S. J. O'Toole

2008-02-23

400

V(RI)_C Photometry of Cepheids in the Magellanic Clouds  

NASA Astrophysics Data System (ADS)

We present V(RI)_C data for 13 Cepheids in the Large Magellanic Cloud and eight in the Small Magellanic Cloud. The total number of new measures is 55 in each wavelength band. The median uncertainty in the photometry is +/-0.03 mag. These results supplement a larger photometric program presented in the second paper in this series which contained 1000 measures (+/-0.01 mag) in each wavelength band on 22 variables with periods in the range 8-133 days.

Barnes, Thomas G., III; Ivans, Inese I.; Martin, Jodie R.; Froning, C. S.; Moffett, Thomas J.

1999-07-01

401

Broadband Photometry of the Large Potentially Hazardous Asteroid 138095 (2000 DK79)  

NASA Astrophysics Data System (ADS)

The Near-Earth Asteroid (NEA)138095 (2000 DK79) was discovered by the LINEAR Sky Survey on February 26, 2010 (MPEC 2000-E42). With a Minimum Orbit Intersection Distance (MOID) of 0.049 AU and an expected diameter between 1.8 km and 3 km, this object has been designated as a Potentially Hazardous Asteroid (PHA) by the Minor Planet Center. We obtained two partial nights of broadband Bessel BVRI photometry at the JPL Table Mountain 0.6-m telescope (TMO) on November 16 and 17, 2013, as summarized in Table 1.

Hicks, M.; Ebelhar, S.

2013-11-01

402

Broadband Photometry of 2007 LE: A Binary Near-Earth Asteroid  

NASA Astrophysics Data System (ADS)

The near-Earth asteroid 2007 LE was discovered on June 2, 2007 by the LINEAR NEO survey (MPEC 2007-L21). The object passed within 0.048 AU of the Earth on June 02 2012 and has been designated as a Potentially Hazardous Asteroid (PHA) my the Minor Planet Center. We obtained 3 nights of time-resolved photometry at the JPL Table Mountain Observatory (TMO) 0.6-m telescope, as summarized in Table 1, and included one night of BVRI imaging [Figure 1].

Hicks, M.; Smythe, W.; Dombroski, D.; Davtyan, T.; Teague, S.; Strojia, C.

2012-06-01

403

Broadband Photometry of the Potentially Hazardous Asteroid 329614 (2003 KU2)  

NASA Astrophysics Data System (ADS)

The near-Earth asteroid 329614 (2003 KU2) was discovered by A. F. Tubbiolo on May 05 2003 (MPEC 2003-K26). Due to its large size (D~1km) and Minimum Orbit Intersection Distance MOID=0.0285 AU, the object has been designated as a Potentially Hazardous Asteroid (PHA) by the IAU Minor Planet Center. We took advantage of the PHA's excellent 2012 apparition to obtain 3 nights of time-resolved Bessel BVRI photometry at the JPL Table Mountain Observatory (TMO) 0.6-m telescope, as summarized in Table 1.

Hicks, M.; Dombroski, D.; Davtyan, T.; Teague, S.; Strojia, C.

2012-07-01

404

THE ARAUCARIA PROJECT: THE DISTANCE TO THE SCULPTOR GALAXY NGC 247 FROM NEAR-INFRARED PHOTOMETRY OF CEPHEID VARIABLES  

SciTech Connect

We have obtained deep near-infrared images in J and K filters of four fields in the Sculptor Group spiral galaxy NGC 247 with the ESO VLT and Infrared Spectrometer and Array Camera. For a sample of 10 Cepheids in these fields, previously discovered by GarcIa-Varela et al. from optical wide-field images, we have determined mean J and K magnitudes and have constructed the period-luminosity (PL) relations in these bands. Using the near-infrared PL relations together with those in the optical V and I bands, we have determined a true distance modulus for NGC 247 of 27.64 mag, with a random uncertainty of {+-}2% and a systematic uncertainty of {approx}4% which is dominated by the effect of unresolved stars on the Cepheid photometry. The mean reddening affecting the NGC 247 Cepheids of E(B - V) = 0.18 {+-} 0.02 mag is mostly produced in the host galaxy itself and is significantly higher than what was found in the previous optical Cepheid studies in NGC 247 of our own group, and Madore et al., leading to a 7% decrease in the previous optical Cepheid distance. As in other studies of our project, the distance modulus of NGC 247 we report is tied to an assumed Large Magellanic Cloud distance modulus of 18.50. Comparison with other distance measurements to NGC 247 shows that the present IR-based Cepheid distance is the most accurate among these determinations. With a distance of 3.4 Mpc, NGC 247 is about 1.5 Mpc more distant than NGC 55 and NGC 300, two other Sculptor Group spirals analyzed before with the same technique by our group.

Gieren, Wolfgang; Pietrzynski, Grzegorz; Szewczyk, Olaf [Universidad de Concepcion, Departamento de Astronomia, Casilla 160-C, Concepcion (Chile); Soszynski, Igor [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478, Warsaw (Poland); Bresolin, Fabio; Kudritzki, Rolf-Peter; Urbaneja, Miguel A. [Institute for Astronomy, University of Hawaii at Manoa, 2680 Woodlawn Drive, Honolulu HI 96822 (United States); Storm, Jesper [Astrophysikalisches Institut Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany); Minniti, Dante [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); GarcIa-Varela, Alejandro [Universidad de los Andes, Departamento de Fisica, Bogota (Colombia)], E-mail: wgieren@astro-udec.cl, E-mail: szewczyk@astro-udec.cl, E-mail: pietrzyn@hubble.cfm.udec.cl, E-mail: soszynsk@astrouw.edu.pl, E-mail: bresolin@ifa.hawaii.edu, E-mail: kud@ifa.hawaii.edu, E-mail: urbaneja@ifa.hawaii.edu, E-mail: jstorm@aip.de, E-mail: dante@astro.puc.cl

2009-08-01

405

To what extent do current and projected increases in surface ozone affect photosynthesis and stomatal conductance of trees? A meta-analytic review of the last 3 decades of experiments.  

PubMed

The surface concentration of ozone ([O(3)]) has risen from less than 10 ppb prior to the industrial revolution to a day-time mean concentration of approximately 40 ppb over much of the northern temperate zone. If current global emission trends continue, surface [O(3)] is projected to rise a further 50% over this century, with larger increases in many locations including Northern Hemisphere forests. This review uses statistical meta-analysis to determine mean effects, and their confidence limits, of both the current and projected elevations of [O(3)] on light-saturated photosynthetic CO(2) uptake (A(sat)) and stomatal conductance (g(s)) in trees. In total, 348 measurements of A(sat) from 61 studies and 266 measures of g(s) from 55 studies were reviewed. Results suggested that the elevation of [O(3)] that has occurred since the industrial revolution is depressing A(sat) and g(s) by 11% (CI 9-13%) and 13% (CI 11-15%), respectively, where CI is the 95% confidence interval. In contrast to angiosperms, gymnosperms were not significantly affected. Both drought and elevated [CO(2)] significantly decreased the effect of ambient [O(3)]. Younger trees (<4 years) were affected less than older trees. Elevation of [O(3)] above current levels caused progressively larger losses of A(sat) and g(s), including gymnosperms. Results are consistent with the expectation that damage to photosynthesis depends on the cumulative uptake of ozone (O(3)) into the leaf. Thus, factors that lower g(s) lessen damage. Where both g(s) and [O(3)] were recorded, an overall decline in A(sat) of 0.21% per mmol m(-2) of estimated cumulative O(3) uptake was calculated. These findings suggest that rising [O(3)], an often overlooked aspect of global atmospheric change, is progressively depressing the ability of temperate and boreal forests to assimilate carbon and transfer water vapour to the atmosphere, with significant potential effects on terrestrial carbon sinks and regional hydrologies. PMID:17661752

Wittig, Victoria E; Ainsworth, Elizabeth A; Long, Stephen P

2007-09-01

406

Strömgren and H? photometry of O and B type stars in star-forming regions. I. Canis Major - Puppis - Vela  

NASA Astrophysics Data System (ADS)

Strömgren and H? photometry of OB-stars generally brighter than 9.5 mag in the Canis Major - Puppis - Vela region of Milky Way is reported. The observations are based on the Milky Way luminous-star (LS) identifications and are designed to create a complete, magnitude-limited sample of LS for this field. We present new uvby photometry for 127 LS and H? photometry for 25 of them. These observations are part of an ongoing effort to improve the completeness of the existing uvbybeta data-base for the bright OB-type stars in the Milky Way, with the aim to investigate the structure of selected star-forming regions. Based on data from the Strömgren Automatic Telescope of the Copenhagen Astronomical Observatory, La Silla. Tables 3 and 4 are only available in electronic form at the CDS via anonymous ftp to 130.79.128.5 or via http://cdsweb.u-strasbg.fr/Abstract.html

Kaltcheva, N. T.; Olsen, E. H.

1999-12-01

407

SUPERNOVA REMNANTS AND THE INTERSTELLAR MEDIUM OF M83: IMAGING AND PHOTOMETRY WITH THE WIDE FIELD CAMERA 3 ON THE HUBBLE SPACE TELESCOPE  

SciTech Connect

We present Wide Field Camera 3 images taken with the Hubble Space Telescope within a single field in the southern grand design star-forming galaxy M83. Based on their size, morphology, and photometry in continuum-subtracted Halpha, [S II], Hbeta, [O III], and [O II] filters, we have identified 60 supernova remnant (SNR) candidates, as well as a handful of young ejecta-dominated candidates. A catalog of these remnants, their sizes and, where possible, their Halpha fluxes are given. Radiative ages and pre-shock densities are derived from those SNRs that have good photometry. The ages lie in the range 2.62 < log (tau{sub rad}/yr) < 5.0, and the pre-shock densities at the blast wave range over 0.56 < n{sub 0}/cm{sup -3} < 1680. Two populations of SNRs have been discovered. These divide into a nuclear and spiral arm group and an inter-arm population. We infer an arm to inter-arm density contrast of 4. The surface flux in diffuse X-rays is correlated with the inferred pre-shock density, indicating that the warm interstellar medium (ISM) is pressurized by the hot X-ray plasma. We also find that the ISM in the nuclear region of M83 is characterized by a very high porosity and pressure, and infer an SNR rate of 1 per 70-150 yr for the nuclear (R < 300 pc) region. On the basis of the number of SNRs detected and their radiative ages, we infer that the lower mass of Type II SNe in M83 is M{sub min} = 16{sup +7}{sub -5} M{sub sun}. Finally, we give evidence for the likely detection of the remnant of the historical supernova, SN1968L.

Dopita, Michael A. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Blair, William P.; Kuntz, Kip D. [Johns Hopkins University, Baltimore, MD (United States); Long, Knox S.; Mutchler, Max; Whitmore, Bradley C.; Bond, Howard E.; MacKenty, John [Space Telescope Science Institute, Baltimore, MD (United States); Balick, Bruce [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Calzetti, Daniela [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Carollo, Marcella [Institute of Astronomy, ETH-Zurich, CH-8093 Zurich (Switzerland); Disney, Michael [Department of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Frogel, Jay A. [Association of Universities for Research in Astronomy, Washington, DC 20005 (United States); O'Connell, Robert [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Hall, Donald [Institute for Astronomy, Honolulu, HI 96822 (United States); Holtzman, Jon A. [New Mexico State University, Las Cruces, NM 88003 (United States); Kimble, Randy A. [Goddard Space Flight Center, Greenbelt, MD 20771 (United States); McCarthy, Patrick [Carnegie Institute of Washington, Pasadena, CA 91101-1292 (United States); Paresce, Francesco [Institute of Space Astrophysics, INAF, 40129 Bologna (Italy); Saha, Abhijit, E-mail: Michael.Dopita@anu.edu.a [NOAO, Tucson, AZ 85726-6732 (United States)

2010-02-20

408

First CCD Photometry of the Interacting Binary AF Geminorum: Evidence for a Gravitationally Bound Third Object?  

NASA Astrophysics Data System (ADS)

AF Geminorum (AF Gem) is an unusual Algol-type eclipsing binary star system in that the primary eclipse is a transit of the cooler, more evolved secondary star in front of the main sequence primary star. Our observations of AF Gem were made using the 0.61-meter Ritchey-Chrétien telescope at the Kutztown University Observatory (Kutztown, Pennsylvania) over 9 nights from 28 Nov 2012 to 6 Feb 2013. A total of 5350 data images were obtained of AF Gem during this time, and the results of our photometry suggest evidence for a third light source which may be gravitationally bound to the system. We present the first CCD photometric study in BVRI for this system, resolve the third light source from our photometry, provide a consistent orbital solution using the Wilson-Devinney code, and present a detailed ephemeris analysis. With an orbital period of 1.24 days, an overall decreasing ephemeris, and a possible third body in the system, AF Gem certainly warrants future photometric and spectroscopic observations.

Yuhas, Bernard J.; Reed, Phillip A.; Chambliss, Carlson R.

2013-07-01

409

HERSCHEL FAR-INFRARED AND SUBMILLIMETER PHOTOMETRY FOR THE KINGFISH SAMPLE OF NEARBY GALAXIES  

SciTech Connect

New far-infrared and submillimeter photometry from the Herschel Space Observatory is presented for 61 nearby galaxies from the Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel (KINGFISH) sample. The spatially integrated fluxes are largely consistent with expectations based on Spitzer far-infrared photometry and extrapolations to longer wavelengths using popular dust emission models. Dwarf irregular galaxies are notable exceptions, as already noted by other authors, as their 500 {mu}m emission shows evidence for a submillimeter excess. In addition, the fraction of dust heating attributed to intense radiation fields associated with photodissociation regions is found to be (21 {+-} 4)% larger when Herschel data are included in the analysis. Dust masses obtained from the dust emission models of Draine and Li are found to be on average nearly a factor of two higher than those based on single-temperature modified blackbodies, as single blackbody curves do not capture the full range of dust temperatures inherent to any galaxy. The discrepancy is largest for galaxies exhibiting the coolest far-infrared colors.

Dale, D. A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Aniano, G.; Draine, B. T. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Engelbracht, C. W.; Hinz, J. L.; Montiel, E. J. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Krause, O.; Groves, B. A. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Roussel, H. [Institut d'Astrophysique de Paris, UMR7095 CNRS, Universite Pierre and Marie Curie, 98 bis Boulevard Arago, 75014 Paris (France); Appleton, P. N. [NASA Herschel Science Center, IPAC, California Institute of Technology, Pasadena, CA 91125 (United States); Armus, L.; Beirao, P. [Spitzer Science Center, California Institute of Technology, MC 314-6, Pasadena, CA 91125 (United States); Bolatto, A. D. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Brandl, B. R. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Calzetti, D.; Crocker, A. F. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Croxall, K. V. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Galametz, M. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Gordon, K. D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Hao, C.-N., E-mail: ddale@uwyo.edu [Tianjin Astrophysics Center, Tianjin Normal University, Tianjin 300387 (China); and others

2012-01-20

410

OAO/MITSuME Photometry of Dwarf Novae. I. SU Ursae Majoris  

NASA Astrophysics Data System (ADS)

We report on simultaneous g', and Rc photometry of SU Ursae Majoris during 2011 December-2012 February using OAO/MITSuME. Our photometry revealed that quiescence is divided into three types based on the magnitude and color. Quiescent light curves showed complicated profiles with various amplitudes and time scales. Although no superoutbursts were observed during our run, five normal outbursts occurred with intervals of 11-21 d. The shapes of the normal outbursts were characteristic of the outside-in type. During the rising phase of a normal outburst, the light curve showed periodic modulations with a period of ˜ 0.048111(354) d, but the origin of this peirod was unclear. We examined daily averaged color-color diagrams, and found that two cycles exist. This implies that the thermal limit cycle in SU UMa is complicated. We newly discovered that g' - Rc becomes red about 3 days prior to an outburst. Although the working mechanism on this reddening is unclear, we propose two possibilities: one is that the inner portion of the accretion disk is filled by matter and obscures the central white dwarf; the other is that the stagnation effect works in the outer region of the accretion disk.

Imada, Akira; Izumiura, Hideyuki; Kuroda, Daisuke; Yanagisawa, Kenshi; Omodaka, Toshihiro; Miyanoshita, Ryo; Kawai, Nobuyuki; Nogami, Daisaku

2013-08-01

411

FUV & NUV Integrated-Light Photometry of Galactic Globular Clusters Using GALEX Archival Data.  

NASA Astrophysics Data System (ADS)

We developed an Integrated-light photometric database in the far (1500 Angstrom) and near (2300 Angstrom) ultraviolet, covering a big data set the Galactic Globular Clusters (GGCs) available in the GALEX GR6 data release. The dataset includes 40 objects, spanning a wide range of stellar population properties. We performed curve of growth and King model fitting on the FUV and NUV images to obtain total magnitudes in these two passbands. Together with existing optical and infrared integrated photometry, age and metallicity estimates available from the literature, this constitutes an important multi-wavelength empirical dataset to compare with unresolved old stellar populations (GCs in distant galaxies). This is the first extension of the integrated-light measurements of old stellar populations in the Far-UV spectral domain. The UV data provide an unique opportunity to test and improve the Simple Stellar Populations (SSP) model performance in this part of the spectrum (e.g. the influence of blue and extreme HB stars and blue stragglers on integrated photometry and spectroscopy).

Munoz Gonzalez, Cesar A.; Pessev, P.; de Propris, R.

2012-01-01

412

THE CHANDRA SURVEY OF THE COSMOS FIELD. II. SOURCE DETECTION AND PHOTOMETRY  

SciTech Connect

The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra program that covers the central contiguous {approx}0.92 deg{sup 2} of the COSMOS field. C-COSMOS is the result of a complex tiling, with every position being observed in up to six overlapping pointings (four overlapping pointings in most of the central {approx}0.45 deg{sup 2} area with the best exposure, and two overlapping pointings in most of the surrounding area, covering an additional {approx}0.47 deg{sup 2}). Therefore, the full exploitation of the C-COSMOS data requires a dedicated and accurate analysis focused on three main issues: (1) maximizing the sensitivity when the point-spread function (PSF) changes strongly among different observations of the same source (from {approx}1 arcsec up to {approx}10 arcsec half-power radius); (2) resolving close pairs; and (3) obtaining the best source localization and count rate. We present here our treatment of four key analysis items: source detection, localization, photometry, and survey sensitivity. Our final procedure consists of a two step procedure: (1) a wavelet detection algorithm to find source candidates and (2) a maximum likelihood PSF fitting algorithm to evaluate the source count rates and the probability that each source candidate is a fluctuation of the background. We discuss the main characteristics of this procedure, which was the result of detailed comparisons between different detection algorithms and photometry tools, calibrated with extensive and dedicated simulations.

Puccetti, S. [ASI Science Data Center, via Galileo Galilei, 00044 Frascati (Italy); Vignali, C. [Dipartimento di Astronomia, Universita di Bologna, via Ranzani 1, Bologna (Italy); Cappelluti, N.; Brunner, H.; Brusa, M.; Fruscione, A.; Finoguenov, A. [Max Planck Institut fuer extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching bei Muenchen (Germany); Fiore, F. [INAF-OAR, via Frascati 33, Monteporzio, I00040 (Italy); Zamorani, G.; Gilli, R.; Coma