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Sample records for vlt uves spectra

  1. NGC 6302: high-ionization permitted lines. Applying X-SSN synthesis to VLT-UVES spectra

    CERN Document Server

    Pequignot, Daniel; Casassus, Simon

    2011-01-01

    A preliminary VLT-UVES spectrum of NGC 6302 (Casassus et al. 2002, MN), which hosts one of the hottest PN nuclei known (Teff ~ 220000 K; Wright et al. 2011, MN), has been recently analysed by means of X-SSN, a spectrum synthesis code for nebulae (Morisset and P\\'equignot). Permitted recombination lines from highly-ionized species are detected/identified for the first time in a PN, and some of them probably for the first time in (Astro)Physics. The need for a homogeneous, high signal-to-noise UVES spectrum for NGC 6302 is advocated.

  2. Saturn's Doppler velocimetry wind measurements with VLT/UVES

    Science.gov (United States)

    Silva, Miguel; Mota Machado, Pedro; Luz, David; Sanchez-Lavega, Agustin; Hueso, Ricardo; Peralta, Javier

    2016-10-01

    We present Doppler wind velocity results of Saturn's zonal flow at ~0.4 mbar pressure level. Our aim is help to constrain the characterization of the equatorial jet at the referred altitude and the latitudinal variation of the zonal winds, to contribute to monitor the spatial and temporal variability in order to achieve a better understanding of the dynamics of Saturn's zonal winds, which Sánchez-Lavega et al. (2003, Nature, 423, 623) have found to have strongly changed in recent years, as the planet approached southern summer solstice.The UVES/VLT instrument has been used, which simultaneously achieves high spectral resolving power and high spatial resolution. The field has been derotated in order to have the aperture aligned perpendicularly to Saturn's rotation axis. In this configuration, spatial information in the East-West direction is preserved in a set of spectra in the direction perpendicular to dispersion.The technique of absolute accelerometry (AA, Connes, 1985, ApSS 110, 211) has been applied to the backscattered solar spectrum in order to determine the Doppler shift associated with the zonal circulation. Our measurements have been made in the wavelength range of 480-680 nm. Previously we successfully adapted this Doppler velocimetry technique for measuring winds at Venus cloud tops (Machado et al. 2012).The observations consisted of 4 blocks of 15 exposures of 90 sec, plus two shorter blocks of 9 exposures, totalling 7.3 hours of telescope time. In order to cover the whole disk the aperture has been offset by 1 arcsec in the North-South direction between consecutive exposures. Most of the northern hemisphere was covered by the rings. Saturn's diameter was 17.4 arcsec, and the slit aperture was 0.3x25 arcsec. The aperture offset between consecutive exposures was 1 arcsec. Two observations blocks of 9 exposures only covered the central part of the disk, and four others covered the whole disk. The sub-terrestrial point was at -26.1 degrees South. The

  3. Wind measurements in Saturn's atmosphere with UVES/VLT ground-based Doppler velocimetry

    Science.gov (United States)

    Machado, Pedro; Silva, Miguel; Peralta, Javier; Luz, David; Sánchez-Lavega, Agustin; Hueso, Ricardo

    2016-04-01

    We will present preliminary Doppler wind velocity results of Saturn's zonal flow at cloud level. Our aim is help to constrain the characterization of the equatorial jet at cloud level and the latitudinal variation of the zonal winds, to measure its spatial and temporal variability, to contribute to monitor the variability in order to achieve a better understanding of the dynamics of Saturn's zonal winds, whose equatorial jet has a complex vertical structure and temporal variability (Sanchez-Lavega et al., Nature, 423, 623, 3003; Garcia-Melendo et al., Geophys. Res. Lett., 37, L22204. 2010). Finally, the complementarity with Cassini, providing an independent set of observations. The UVES/VLT instrument has been used, which simultaneously achieves high spectral resolving power and high spatial resolution. The field has been derotated in order to have the aperture aligned perpendicularly to Saturn's rotation axis. In this configuration, spatial information in the East-West direction is preserved in a set of spectra in the direction perpendicular to dispersion. The technique of absolute accelerometry (AA, Connes, 1985, ApSS 110, 211) has been applied to the backscattered solar spectrum in order to determine the Doppler shift associated with the zonal circulation. Our measurements have been made in the wavelength range of 480-680 nm. Previously we successfully adapted this Doppler velocimetry technique for measuring winds at Venus cloud tops (Machado et al. 2012). In the present study we will show the adaptation of this method for Saturn's case. Since the AA technique only allows to compare spectra where the line shifts are within the line width, in fast rotating atmospheres (as is the case of Saturn) the spectra must be compared by pairs from adjacent areas of the disk (adjacent pixels in the slit). We will use coordinated observations from the Cassini's Visible and Infrared Mapping Spectrometer (VIMS), in order to compare with the Doppler winds obtained from the UVES/VLT

  4. VLT\\/UVES Abundances in Four Nearby Dwarf Spheroidal Galaxies I. Nucleosynthesis and Abundance Ratios

    CERN Document Server

    Shetrone, M; Tolstoy, E; Primas, F; Hill, V; Kaufer, A

    2003-01-01

    We have used UVES on VLT-UT2 to take spectra of 15 red giants in the Sculptor, Fornax, Carina and Leo I dwarf spheroidal galaxies. We measure the abundances of alpha, iron peak, s and r-process elements. No dSph giants in our sample show the deep mixing abundance pattern seen in nearly all globular clusters. At a given metallicity, the dSph giants exhibit lower [el/Fe] abundance ratios for the alpha elements than stars in the Galactic halo. This can be caused by a slow star formation rate and contribution from Type Ia SN, and/or a small star formation event (low total mass) and mass dependent Type II SN yields. Differences in the even-Z [el/Fe] ratios between these galaxies, as well as differences in the evolution of the s&r-process elements are interpreted in terms of their star formation histories. Comparison of the dSph abundances with those of the Galactic halo reveals some consistencies. In particular, we find stars that mimic the abundance pattern found by Nissen & Shuster (1997) for metal-rich,...

  5. VLT\\/UVES Abundances in Four Nearby Dwarf Spheroidal Galaxies II. Implications for Understanding Galaxy Evolution

    CERN Document Server

    Tolstoy, E; Shetrone, M; Primas, F; Hill, V; Szeifert, A K T; Tolstoy, Eline

    2003-01-01

    We have used UVES on VLT-UT2 to take spectra of 15 individual red giant stars in the centers of four nearby dwarf spheroidal galaxies: Sculptor, Fornax, Carina and Leo I. We measure the abundance variations of numerous elements in these low mass stars with a range of ages (1-15Gyr old). This means that we can effectively measure the chemical evolution of these galaxies WITH TIME. Our results show a significant spread in metallicity with age, but an overall trend consistent with what might be expected from a closed (or perhaps leaky) box chemical evolution scenario over the last 10-15Gyr. We notice that each of these galaxies show broadly similar abundance patterns for all elements measured. This suggests a fairly uniform progression of chemical evolution with time, despite quite a large range of star formation histories. It seems likely that these galaxies had similar initial conditions, and evolve in a similar manner with star formation occurring at a uniformly low rate, even if at different times. With our ...

  6. VLT/UVES Observations of Interstellar Molecules and Diffuse Bands in the Magellanic Clouds

    CERN Document Server

    Welty, D E; Gredel, R; Lambert, D L; Thorburn, J A

    2006-01-01

    We discuss the abundances of interstellar CH, CH+, and CN in the Magellanic Clouds (MC), derived from spectra of 7 SMC and 13 LMC stars obtained (mostly) with the VLT/UVES. CH and/or CH+ are detected toward 3 SMC and 9 LMC stars; CN is detected toward 2 stars. In the MC, the CH/H2 ratio is comparable to that found for diffuse Galactic molecular clouds in some sight lines, but is lower by factors up to 10-15 in others. The abundance of CH in the MC thus appears to depend on local physical conditions -- and not just on metallicity. The observed relationships between the column density of CH and those of CN, CH+, Na I, and K I in the MC are generally consistent with the trends observed in our Galaxy. Using existing data for the rotational populations of H2, we estimate temperatures, radiation field strengths, and local hydrogen densities for the diffuse molecular gas. Densities estimated from N(CH), assuming that CH is produced via steady-state gas-phase reactions, are considerably higher; much better agreement ...

  7. VLT/UVES constraints on the cosmological variability of the fine-structure constant

    CERN Document Server

    Levshakov, S A; Molaro, P; D'Odorico, S

    2004-01-01

    A differential many-multiplet (DMM) technique is developed to probe the variability of alpha. Applied to the FeII lines of the metal absorption line system at zabs = 1.839 in the spectrum of Q1101-264 obtained by means of the UV-Visual Echelle Spectrograph (UVES) at the ESO Very Large Telescope (VLT), the DMM provides da/a = (4.3+/-7.8) 10^{-6}.The zabs = 1.15 FeII system toward HE0515-4414 has been re-analyzed by the DMM method thus obtaining for the combined sample da/a = (0.7+/-3.1) 10^{-6}. These values are shifted with respect to the Keck/HIRES mean da/a = (-5.7+/-1.1) 10^{-6} (Murphy et al. 2004) at very high confidence level (95%). The fundamental photon noise limitation in the da/a measurement with the VLT/UVES is discussed to figure the prospects for future observations. It is suggested that with a spectrograph of 10 times the UVES resolution coupled to a 100m class telescope the present Oklo level (da/a >= 4.5 10^{-8}) can be achieved along cosmological distances with differential measurements of da...

  8. Revealing deuterium Balmer lines in HII regions with VLT-UVES

    CERN Document Server

    Hébrard, G; Walsh, J R; Vidal-Madjar, A; Ferlet, R

    2000-01-01

    The search for deuterium Balmer lines with VLT-UVES is reported in HII regions of the Galaxy and the Magellanic Clouds. The DI lines appear as faint, narrow emission features in the blue wings of the HI Balmer lines and can be distinguished from high-velocity HI emission. The previous identification to deuterium is re-inforced beyond doubt. The detection of D-alpha and D-beta in Orion (Hebrard et al. 2000) is confirmed and deuterium lines are now detected up to at least D-eta. The UVES observations provide the first detection of Balmer DI lines in four new HII regions (M 8, M 16, M 20, and DEM S 103 in SMC), demonstrating that these lines are of common occurence.

  9. VLT/UVES abundances in four nearby dwarf spheroidal galaxies. I. Nucleosynthesis and abundance ratios

    NARCIS (Netherlands)

    Shetrone, M; Venn, KA; Tolstoy, E; Primas, F; Hill, [No Value; Kaufer, A

    2003-01-01

    We have used the Ultraviolet Echelle Spectrograph (UVES) on Kueyen (UT2) of the Very Large Telescope to take spectra of 15 individual red giants in the Sculptor, Fornax, Carina, and Leo I dwarf spheroidal galaxies (dSph's). We measure the abundances of alpha-, iron peak, first s-process, second s-pr

  10. VLT/UVES abundances in four nearby dwarf spheroidal galaxies. II. Implications for understanding galaxy evolution

    NARCIS (Netherlands)

    Tolstoy, E; Venn, KA; Shetrone, M; Primas, F; Hill, [No Value; Kaufer, A; Szeifert, T

    2003-01-01

    We have used the Ultraviolet Visual-Echelle Spectrograph (UVES) on Kueyen (UT2) of the Very Large Telescope to take spectra of 15 individual red giant stars in the centers of four nearby dwarf spheroidal galaxies (dSph's) : Sculptor, Fornax, Carina, and Leo I. We measure the abundance variations of

  11. VLT/UVES constraints on the cosmological variability of the fine-structure constant

    Science.gov (United States)

    Levshakov, S. A.; Centurión, M.; Molaro, P.; D'Odorico, S.

    2005-05-01

    We propose a new methodology for probing the cosmological variability of α from pairs of Fe II lines (SIDAM, single ion differential α measurement) observed in individual exposures from a high resolution spectrograph. By this we avoid the influence of the spectral shifts due to (i) ionization inhomogeneities in the absorbers; and (ii) non-zero offsets between different exposures. Applied to the Fe II lines of the metal absorption line system at z_abs = 1.839 in the spectrum of Q 1101-264 obtained by means of the UV-Visual Echelle Spectrograph (UVES) at the ESO Very Large Telescope (VLT), SIDAM provides Δα/α = (2.4±3.8_stat)×10-6. The z_abs = 1.15 Fe II system toward HE 0515-4414 has been re-analyzed by this method thus obtaining for the combined sample Δα/α = (0.4±1.5_stat)×10-6. These values are shifted with respect to the Keck/HIRES mean Δα/α = (-5.7 ± 1.1_stat)×10-6 (Murphy et al. 2004) at very high confidence level (95%). The fundamental photon noise limitation in the Δα/α measurement with the VLT/UVES is discussed to figure the prospects for future observations. It is suggested that with a spectrograph of ~10 times the UVES dispersion coupled to a 100 m class telescope the present Oklo level (Δα/α ≥ 4.5 × 10-8) can be achieved along cosmological distances with differential measurements of Δα/α.

  12. Search for alpha variation in UVES spectra: Analysis of C IV and Si IV doublets towards QSO 1101-264

    Science.gov (United States)

    Martínez Fiorenzano, A. F.; Vladilo, G.; Bonifacio, P.

    Motivated by previous studies of QSO spectra that reported a variation of the fine structure constant alpha , a search for C IV and Si IV doublets was conducted in the absorption spectrum toward QSO 1101-264, obtained by VLT-UVES during the Science Verification. Seven C IV and two Si IV systems were identified and accurate measurements of wavelengths over the redshift range 1.1862 < z < 1.8377 were performed. After a careful selection of pairs of lines, the ``Alkali Doublet" method with a derived analitical expression for the error analysis was applied to compute the alpha variation. The result according in magnitud order with previous doublets measurements, corresponds to one Si IV system: Delta alpha /alpha = (- 3.09 +/- 8.46) x 10-5. Data from UVES-VLT.

  13. Quantification of non-LTE contributions to OH rotational temperatures based on VLT/X-shooter, VLT/UVES, and TIMED/SABER data

    Science.gov (United States)

    Noll, Stefan; Kausch, Wolfgang; Kimeswenger, Stefan; Proxauf, Bastian; Unterguggenberger, Stefanie; Jones, Amy M.

    2016-04-01

    The hydroxyl (OH) airglow emission is very valuable for estimating atmospheric temperatures at about 87 km because it is relatively easy to measure. The usual approach is based on intensity ratios of OH lines with low rotational upper levels of a given band and the assumption of a Boltzmann distribution of the level populations consistent with the ambient temperature. However, this assumption can be unrealistic if the frequency of thermalising collisions is too low, which is most likely at the highest emission altitudes. We have investigated the amounts of possible non-LTE contributions to the measured OH rotational temperatures depending on the selected lines, band, and time of observation. For this, we used several hundred spectra from the echelle spectrograph X-shooter at the Very Large Telescope (VLT) at Cerro Paranal in Chile. These data with a very wide wavelength coverage allowed us to simultaneously measure temperatures for 25 OH bands and two O2 bands. The latter were used to obtain reference temperatures, which is possible since the radiative lifetimes of the upper states are sufficiently long for establishing full thermalisation for the populations of the different rotational levels. For a comparison of the resulting temperatures, a correction of the different emission altitudes is required. Hence, we also used CO2-based temperature and OH and O2 emission profile data from the SABER multi-channel radiometer on the TIMED satellite. The altitude-corrected OH rotational temperatures show significant non-LTE effects for higher vibrational levels of the upper state v' and especially even v'. The maximum deviations of more than 10 K were found for v' = 8. The non-LTE effects can vary within a range of a few K. The studied nocturnal variations indicate that the non-LTE contributions increase when the emission layer rises. Finally, we will also present first results for several thousand spectra taken with the VLT high-resolution optical echelle spectrograph UVES

  14. The beryllium abundance in the very metal-poor halo star G 64-12 from VLT/UVES observations

    CERN Document Server

    Primas, F; Nissen, P E; Hill, V

    2000-01-01

    We report on a new spectroscopic analysis of the very metal deficient star G 64-12 ([Fe/H]=-3.3), aimed at determining, for the first time, its Be content. The spectra were observed during the Science Verification of UVES, the ESO VLT Ultraviolet and Visible Echelle Spectrograph. The high resolution (~48,000) and high S/N (~130 per pixel) achieved at the wavelengths of the BeII resonance doublet allowed an accurate determination of its abundance: log N(Be/H) = -13.10 +/- 0.15 dex. The Be abundance is significantly higher than expected from previous measurements of Be in stars of similar metallicity (3D and NLTE corrections acting to make a slightly higher value than an LTE analysis). When compared to iron, the high [Be/Fe] ratio thus found may suggest a flattening in the beryllium evolutionary trend at the lowest metallicity end or the presence of dispersion at early epochs of galactic evolution.

  15. Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars

    CERN Document Server

    Smiljanic, R; Bergemann, M; Frasca, A; Magrini, L; Masseron, T; Pancino, E; Ruchti, G; Roman, I San; Sbordone, L; Sousa, S G; Tabernero, H; Tautvaisiene, G; Valentini, M; Weber, M; Worley, C C; Adibekyan, V Zh; Prieto, C Allende; Barisevicius, G; Biazzo, K; Blanco-Cuaresma, S; Bonifacio, P; Bragaglia, A; Caffau, E; Cantat-Gaudin, T; Chorniy, Y; de Laverny, P; Delgado-Mena, E; Donati, P; Duffau, S; Franciosini, E; Friel, E; Geisler, D; Hernandez, J I Gonzalez; Gruyters, P; Guiglion, G; Hansen, C J; Heiter, U; Hill, V; Jacobson, H R; Jofre, P; Jonsson, H; Lanzafame, A C; Lardo, C; Ludwig, H G; Maiorca, E; Mikolaitis, S; Montes, D; Morel, T; Mucciarelli, A; Munoz, C; Nordlander, T; Pasquini, L; Puzeras, E; Recio-Blanco, A; Ryde, N; Sacco, G; Santos, N C; Serenelli, A M; Sordo, R; Soubiran, C; Spina, L; Steffen, M; Vallenari, A; Van Eck, S; Villanova, S; Gilmore, G; Randich, S; Asplund, M; Binney, J; Drew, J; Feltzing, S; Ferguson, A; Jeffries, R; Micela, G; Negueruela, I; Prusti, T; Rix, H-W; Alfaro, E; Babusiaux, C; Bensby, T; Blomme, R; Flaccomio, E; Francois, P; Irwin, M; Koposov, S; Walton, N; Bayo, A; Carraro, G; Costado, M T; Damiani, F; Edvardsson, B; Hourihane, A; Jackson, R; Lewis, J; Lind, K; Marconi, G; Martayan, C; Monaco, L; Morbidelli, L; Prisinzano, L; Zaggia, S

    2014-01-01

    The Gaia-ESO Survey is obtaining high-quality spectroscopic data for about 10^5 stars using FLAMES at the VLT. UVES high-resolution spectra are being collected for about 5000 FGK-type stars. These UVES spectra are analyzed in parallel by several state-of-the-art methodologies. Our aim is to present how these analyses were implemented, to discuss their results, and to describe how a final recommended parameter scale is defined. We also discuss the precision (method-to-method dispersion) and accuracy (biases with respect to the reference values) of the final parameters. These results are part of the Gaia-ESO 2nd internal release and will be part of its 1st public release of advanced data products. The final parameter scale is tied to the one defined by the Gaia benchmark stars, a set of stars with fundamental atmospheric parameters. A set of open and globular clusters is used to evaluate the physical soundness of the results. Each methodology is judged against the benchmark stars to define weights in three diff...

  16. Search for alpha variation in UVES spectra: Analysis of C IV and Si IV doublets towards QSO 1101-264

    CERN Document Server

    Fiorenzano, A F M; Bonifacio, P

    2003-01-01

    Motivated by previous studies of QSO spectra that reported a variation of the fine structure constant alpha, a search for C IV and Si IV doublets was conducted in the absorption spectrum towardS QSO 1101-264, obtained by VLT-UVES during the Science Verification. Seven C IV and two Si IV systems were identified and accurate measurements of wavelengths over the redshift range 1.1862 < z < 1.8377 were performed. After a careful selection of pairs of lines, the "Alkali Doublet" method with a derived analitical expression for the error analysis was applied to compute the alpha variation. The result according in magnitud order with previous doublets measurements, corresponds to one Si IV system: Delta alpha/alpha = (- 3.09 +/- 8.46) x 10^(-5).

  17. The AMBRE Project: Stellar Parameterisation of the ESO:UVES archived spectra

    CERN Document Server

    Worley, C C; Recio-Blanco, A; Hill, V; Bijaoui, A

    2016-01-01

    The AMBRE Project is a collaboration between the European Southern Observatory (ESO) and the Observatoire de la Cote d'Azur (OCA) that has been established in order to carry out the determination of stellar atmospheric parameters for the archived spectra of four ESO spectrographs. The analysis of the UVES archived spectra for their stellar parameters has been completed in the third phase of the AMBRE Project. From the complete ESO:UVES archive dataset that was received covering the period 2000 to 2010, 51921 spectra for the six standard setups were analysed. The AMBRE analysis pipeline uses the stellar parameterisation algorithm MATISSE to obtain the stellar atmospheric parameters. The synthetic grid is currently constrained to FGKM stars only. Stellar atmospheric parameters are reported for 12,403 of the 51,921 UVES archived spectra analysed in AMBRE:UVES. This equates to ~23.9% of the sample and ~3,708 stars. Effective temperature, surface gravity, metallicity and alpha element to iron ratio abundances are ...

  18. Rapid-Response Mode VLT/UVES spectroscopy of GRB060418: Conclusive evidence for UV pumping from the time evolution of FeII and NiII excited- and metastable-level populations

    CERN Document Server

    Vreeswijk, P M; Smette, A; Ellison, S L; Jaunsen, A O; Andersen, M I; Fruchter, A S; Fynbo, J P U; Hjorth, J; Kaufer, A; Møller, P; Petitjean, P; Savaglio, S; Wijers, R A M J

    2006-01-01

    We present high-resolution spectroscopic observations of GRB 060418, obtained with VLT/UVES. These observations were triggered using the VLT Rapid-Response Mode (RRM), which allows for automated observations of transient phenomena, without any human intervention. This resulted in the first UVES exposure of GRB 060418 to be started only 10 minutes after the initial Swift satellite trigger. A sequence of spectra covering 330-670 nm were acquired at 11, 16, 25, 41 and 71 minutes (mid-exposure) after the trigger, with a resolving power of 7 km/s, and a signal-to-noise ratio of 10-15. This time-series clearly shows evidence for time variability of allowed transitions involving Fe II fine-structure levels, and metastable levels of both Fe II and Ni II, at the host-galaxy redshift z=1.490. We model the observed evolution of the level populations with three different excitation mechanisms: collisions, excitation by infra-red photons, and fluorescence following excitation by ultraviolet photons. Our data allow us to r...

  19. The Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars

    Science.gov (United States)

    Smiljanic, R.; Korn, A. J.; Bergemann, M.; Frasca, A.; Magrini, L.; Masseron, T.; Pancino, E.; Ruchti, G.; San Roman, I.; Sbordone, L.; Sousa, S. G.; Tabernero, H.; Tautvaišienė, G.; Valentini, M.; Weber, M.; Worley, C. C.; Adibekyan, V. Zh.; Allende Prieto, C.; Barisevičius, G.; Biazzo, K.; Blanco-Cuaresma, S.; Bonifacio, P.; Bragaglia, A.; Caffau, E.; Cantat-Gaudin, T.; Chorniy, Y.; de Laverny, P.; Delgado-Mena, E.; Donati, P.; Duffau, S.; Franciosini, E.; Friel, E.; Geisler, D.; González Hernández, J. I.; Gruyters, P.; Guiglion, G.; Hansen, C. J.; Heiter, U.; Hill, V.; Jacobson, H. R.; Jofre, P.; Jönsson, H.; Lanzafame, A. C.; Lardo, C.; Ludwig, H.-G.; Maiorca, E.; Mikolaitis, Š.; Montes, D.; Morel, T.; Mucciarelli, A.; Muñoz, C.; Nordlander, T.; Pasquini, L.; Puzeras, E.; Recio-Blanco, A.; Ryde, N.; Sacco, G.; Santos, N. C.; Serenelli, A. M.; Sordo, R.; Soubiran, C.; Spina, L.; Steffen, M.; Vallenari, A.; Van Eck, S.; Villanova, S.; Gilmore, G.; Randich, S.; Asplund, M.; Binney, J.; Drew, J.; Feltzing, S.; Ferguson, A.; Jeffries, R.; Micela, G.; Negueruela, I.; Prusti, T.; Rix, H.-W.; Alfaro, E.; Babusiaux, C.; Bensby, T.; Blomme, R.; Flaccomio, E.; François, P.; Irwin, M.; Koposov, S.; Walton, N.; Bayo, A.; Carraro, G.; Costado, M. T.; Damiani, F.; Edvardsson, B.; Hourihane, A.; Jackson, R.; Lewis, J.; Lind, K.; Marconi, G.; Martayan, C.; Monaco, L.; Morbidelli, L.; Prisinzano, L.; Zaggia, S.

    2014-10-01

    Context. The ongoing Gaia-ESO Public Spectroscopic Survey is using FLAMES at the VLT to obtain high-quality medium-resolution Giraffe spectra for about 105 stars and high-resolution UVES spectra for about 5000 stars. With UVES, the Survey has already observed 1447 FGK-type stars. Aims: These UVES spectra are analyzed in parallel by several state-of-the-art methodologies. Our aim is to present how these analyses were implemented, to discuss their results, and to describe how a final recommended parameter scale is defined. We also discuss the precision (method-to-method dispersion) and accuracy (biases with respect to the reference values) of the final parameters. These results are part of the Gaia-ESO second internal release and will be part of its first public release of advanced data products. Methods: The final parameter scale is tied to the scale defined by the Gaia benchmark stars, a set of stars with fundamental atmospheric parameters. In addition, a set of open and globular clusters is used to evaluate the physical soundness of the results. Each of the implemented methodologies is judged against the benchmark stars to define weights in three different regions of the parameter space. The final recommended results are the weighted medians of those from the individual methods. Results: The recommended results successfully reproduce the atmospheric parameters of the benchmark stars and the expected Teff-log g relation of the calibrating clusters. Atmospheric parameters and abundances have been determined for 1301 FGK-type stars observed with UVES. The median of the method-to-method dispersion of the atmospheric parameters is 55 K for Teff, 0.13 dex for log g and 0.07 dex for [Fe/H]. Systematic biases are estimated to be between 50-100 K for Teff, 0.10-0.25 dex for log g and 0.05-0.10 dex for [Fe/H]. Abundances for 24 elements were derived: C, N, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ba, Nd, and Eu. The typical method

  20. Rapid-response mode VLT/UVES spectroscopy of super iron-rich gas exposed to GRB 080310. Evidence of ionization in action and episodic star formation in the host

    CERN Document Server

    De Cia, A; Fox, A J; Vreeswijk, P M; Smette, A; Petitjean, P; Bjornsson, G; Fynbo, J P U; Hjorth, J; Jakobsson, P

    2012-01-01

    We analyse high-resolution near-UV and optical spectra of the afterglow of GRB 080310, obtained with the Very Large Telescope Ultraviolet and Visual Echelle Spectrograph (VLT/UVES), to investigate the circumburst environment and the interstellar medium of the gamma-ray burst (GRB) host galaxy. The VLT rapid-response mode (RRM) enabled the observations to start only 13 minutes after the Swift trigger and a series of four exposures to be collected before dawn. A low neutral-hydrogen column-density (log N (HI) = 18.7) is measured at the host-galaxy redshift of z = 2.42743. At this redshift, we also detect a large number of resonance ground-state absorption lines (e.g., CII, MgII, AlII, SiII, CrII, CIV, SiIV), as well as time-varying absorption from the fine-structure levels of FeII. Time-varying absorption from a highly excited FeIII energy level (7S3), giving rise to the so-called UV34 line triplet, is also detected, for the first time in a GRB afterglow. The CrII ground-state and all observed FeII energy level...

  1. The Gaia-ESO Survey: processing of the FLAMES-UVES spectra

    CERN Document Server

    Sacco, G G; Franciosini, E; Maiorca, E; Randich, S; Modigliani, A; Gilmore, G; Asplund, M; Binney, J; Bonifacio, P; Drew, J; Feltzing, S; Ferguson, A; Jeffries, R; Micela, G; Negueruela, I; Prusti, T; Rix, H -W; Vallenari, A; Alfaro, E; Prieto, C Allende; Babusiaux, C; Bensby, T; Blomme, R; Bragaglia, A; Flaccomio, E; Francois, P; Hambly, N; Irwin, M; Koposov, S; Korn, A; Lanzafame, A; Pancino, E; Recio-Blanco, A; Smiljanic, R; Van Eck, S; Walton, N; Bergemann, M; Costado, M T; de Laverny, P; Heiter, U; Hill, V; Hourihane, A; Jackson, R; Jofre, P; Lewis, J; Lind, K; Lardo, C; Magrini, L; Masseron, T; Prisinzano, L; Worley, C

    2014-01-01

    The Gaia-ESO Survey is a large public spectroscopic survey that aims to derive radial velocities and fundamental parameters of about 10^5 Milky Way stars in the field and in clusters. Observations are carried out with the multi-object optical spectrograph FLAMES, using simultaneously the medium resolution (R~20,000) GIRAFFE spectrograph and the high resolution (R~47,000) UVES spectrograph. In this paper, we describe the methods and the software used for the data reduction, the derivation of the radial velocities, and the quality control of the FLAMES-UVES spectra. Data reduction has been performed using a workflow specifically developed for this project. This workflow runs the ESO public pipeline optimizing the data reduction for the Gaia-ESO Survey, performs automatically sky subtraction, barycentric correction and normalisation, and calculates radial velocities and a first guess of the rotational velocities. The quality control is performed using the output parameters from the ESO pipeline, by a visual insp...

  2. [Discrimination of pressed and extracted camellia oils by Vis/NIR spectra combined with UVE-PLS-LDA].

    Science.gov (United States)

    Wen, Zhen-cai; Sun, Tong; Geng, Xiang; Liu, Mu-hua

    2013-09-01

    Camellia oil is a special and high quality edible oil in China, and quality of pressed camellia oils is superior to extracted camellia oils. The objective of the present research was to discriminate pressed and extracted camellia oils by visible/near infrared (Vis/NIR) spectroscopy. The transmission spectra of pressed and extracted camellia oil samples were acquired using a QualitySpec spectrometer in the wavelength range of 350-1800 nm. Uninformative variable elimination (UVE) was used to select informative wavelength variables, and eliminate uninformative wavelength variables, then partial least squares combined with linear discriminant analysis (PLS-LDA) was used to develop classification model. At last, the classification model was used to discriminate 26 samples in the prediction set. The results indicate that UVE-PLS-LDA is an efficient discrimination and classification method, pressed and extracted camellia oils can be discriminated well by the classification model developed by UVE-PLS-LDA, the accurate rate is 100% for both samples in the calibration and prediction sets. So, Vis/NIR spectra combined with UVE-PLS-LDA is an effective method for discriminating pressed and extracted camellia oils.

  3. VLT/UVES spectroscopy of V4332 Sagittarii in 2005: The best view on a decade-old stellar-merger remnant

    CERN Document Server

    Tylenda, R; Kamiński, T; Schmidt, M

    2014-01-01

    V4332 Sgr is a red transient (red nova) whose eruption was observed in 1994. The remnant of the eruption shows a unique optical spectrum: strong emission lines of atomes and molecules superimposed on a M-type stellar spectrum. The stellar-like remnant is presumably embedded in a disc-like dusty envelope orientated almost face-on. The observed optical spectrum is supposed to result from interactions of the central-star radiation with dust and gas in the disc and outflows initiated in 1994. We have reduced and measured a high-resolution (R ~ 40000) spectrum of V4332 Sgr obtained with VLT/UVES in April/May 2005. The spectrum comes from the ESO archives and is the best quality spectrum of the object ever obtained. We have identified and measured over 200 emission features belonging to 11 elements and 6 molecules. The continuous, stellar-like component can be classified as ~M3. The radial velocity of the object, as derived from narrow atomic emission line, is -75 km/s. The interstellar reddening was estimated as b...

  4. SBS 0335-052E+W: deep VLT/FORS+UVES spectroscopy of the pair of the lowest-metallicity blue compact dwarf galaxies

    CERN Document Server

    Izotov, Yu I; Fricke, K J; Papaderos, P

    2009-01-01

    (abridged) We present deep archival VLT/FORS1+UVES spectroscopic observations of the system of two blue compact dwarf (BCD) galaxies SBS 0335-052E and SBS 0335-052W. Our aim is to derive element abundances in different HII regions of this unique system of galaxies and to study spatial abundance variations. We determine abundances of helium, nitrogen, oxygen, neon, sulfur, chlorine, argon and iron. The oxygen abundance in the brighter eastern galaxy varies in the range 7.11 to 7.32 in different HII regions supporting previous findings and suggesting the presence of oxygen abundance variations on spatial scales of ~1-2 kpc. The oxygen abundance in the brightest region No.1 of SBS 0335-052W is 7.22+/-0.07, consistent with previous determinations.Three other HII regions are much more metal-poor with an unprecedently low oxygen abundance of 12+logO/H=7.01+/-0.07 (region No.2), 6.98+/-0.06 (region No.3), and 6.86+/-0.14 (region No.4). These are the lowest oxygen abundances ever derived in emission-line galaxies. He...

  5. VLT/UVES observations of peculiar alpha abundances in a sub-DLA at z ~ 1.8 towards the quasar B1101-26

    CERN Document Server

    Fox, Anne; Fechner, Cora

    2014-01-01

    We present a detailed analysis of chemical abundances in a sub-damped Lyman alpha absorber at z=1.839 towards the quasar B1101-26, based on a very-high-resolution (R ~ 75,000) and high-signal-to-noise (S/N >100) spectrum observed with the UV Visual Echelle spectrograph (UVES) installed on the ESO Very Large Telescope (VLT). The absorption line profiles are resolved into a maximum of eleven velocity components spanning a rest-frame velocity range of 200 km/s. Detected ions include CII, CIV, NII, OI, MgI, MgII, AlII, AlIII, SiII, SiIII, SiIV, FeII, and possibly SII. The total neutral hydrogen column density is log N(HI) = 19.48 +/- 0.01. From measurements of column densities and Doppler parameters we estimate element abundances of the above-given elements. The overall metallicity, as traced by [OI/HI], is -1.56 +/- 0.01. For the nitrogen-to-oxygen ratio we derive an upper limit of [NI/OI] < -0.65, which suggests a chemically young absorption line system. This is supported by a supersolar alpha/Fe ratio of [S...

  6. Abundance analysis of the supergiant stars HD 80057 and HD 80404 based on their UVES Spectra

    CERN Document Server

    Tanrıverdi, Taner

    2015-01-01

    This study presents elemental abundances of the early A-type supergiant HD 80057 and the late A-type supergiant HD80404. High resolution and high signal-to-noise ratio spectra published by the UVES Paranal Observatory Project (Bagnulo et al., 2003) were analysed to compute their elemental abundances using ATLAS9 (Kurucz, 1993, 2005; Sbordone et al., 2004). In our analysis we assumed local thermodynamic equilibrium. The atmospheric parameters of HD 80057 used in this study are from Firnstein & Przybilla (2012), and that of HD80404 are derived from spectral energy distribution, ionization equilibria of Cr I/II and Fe I/II, and the fits to the wings of Balmer lines and Paschen lines as Teff = 7700 +/- 150 K and log g=1.60 +/- 0.15 (in cgs). The microturbulent velocities of HD 80057 and HD 80404 have been determined as 4.3 +/- 0.1 and 2.2 +/- 0.7 km s^-1 . The rotational velocities are 15 +/-1 and 7 +/- 2 km s^-1 and their macroturbulence velocities are 24 +/-2 and 2+/-1 km s^-1 . We have given the abundances...

  7. Variations in VLT/UVES-based OH rotational temperatures for time scales from hours to 15 years

    Science.gov (United States)

    Noll, Stefan; Kimeswenger, Stefan; Proxauf, Bastian; Kausch, Wolfgang; Unterguggenberger, Stefanie; Jones, Amy M.

    2017-04-01

    Hydroxyl (OH) emission is an important tracer of the climate, chemistry, and dynamics of the Earth's mesopause region. However, the relation of intensity variations in different OH lines is not well understood yet. This is critical for the most popular use of OH lines: the estimate of ambient temperatures based on transitions at low rotational levels of the same band. It is possible that the measured variability of the derived rotational temperature does not coincide with changes in the ambient temperature. Such differences can be caused by varying deviations from the local thermodynamic equilibrium (LTE) for the population distribution over the considered rotational levels. The non-LTE effects depend on the ratio of the thermalising collisions (mostly related to molecular oxygen) and competing radiative transitions or collisions without thermalisation of the rotational level distribution. Therefore, significant changes in the vertical structure of excited OH and its main quenchers can affect the temperature measurements. We have investigated the variability of OH rotational temperatures and the corresponding contributions of non-LTE effects for different OH bands and time scales up to 15 years based on data of the high-resolution echelle spectrograph UVES at the Very Large Telescope at Cerro Paranal in Chile. In order to link the measured rotational temperatures with the structure of the OH emission layer, we have also studied OH emission and kinetic temperature profiles from the multi-channel radiometer SABER on the TIMED satellite taken between 2002 and 2015. The results show that non-LTE contributions can significantly affect the OH rotational temperatures. Their variations can be especially strong during the night and for high upper vibrational levels of the transitions, where amplitudes of several Kelvins can be measured. They appear to be weak if long-term variations such as those caused by the solar cycle are investigated. These differences in the response

  8. VLT/UVES spectroscopy of Wray 977, the hypergiant companion to the X-ray pulsar GX301-2

    NARCIS (Netherlands)

    Kaper, L.; van der Meer, A.; Najarro, F.

    2006-01-01

    Model atmosphere fits to high-resolution optical spectra of Wray 977 confirm the B hypergiant classification of the massive companion to the X-ray pulsar GX301-2. The models give a radius of 62 Ro, an effective temperature of 18 100 K and a luminosity of 5 × 105 Lo. These values are somewhat reduced

  9. VLT-UVES observations of the Balmer line variations of eta Carinae during the 2003 spectroscopic event

    CERN Document Server

    Weis, K; Bomans, D J; Davidson, K; Gull, T R; Humphreys, R M; Weis, Kerstin; Stahl, Otmar; Bomans, Dominik J.; Davidson, Kris; Gull, Theodore R.; Humphreys, Roberta M.

    2004-01-01

    We present high spectral resolution echelle observations of the Balmer line variations during the 2003.5 ``spectroscopic event'' of eta Carinae. Spectra have been recorded of both eta Carinae and the Homunculus at the FOS4 position in its SE lobe. This spot shows a reflected stellar spectrum which is less contaminated by nebular emission lines than ground-based observations of the central object itself. Our observations show that the spectroscopic event is much less pronounced at this position than when seen directly on eta Car using HST/STIS. Assuming that the reflected spectrum is indeed latitude dependent this indicates that the spectral changes during the event seen pole-on (FOS4) are different from those closer to the equator (directly on the star). In contrast to the spectrum of the star, the scattered spectrum of FOS4 always shows pronounced P Cygni absorption with little variation across the ``spectroscopic event''. After that event an additional high-velocity absorption component appears. The emissio...

  10. The bispectrum of the Lyman-alpha forest at z~2-2.4 from a Large sample of UVES QSO Absorption Spectra (LUQAS)

    CERN Document Server

    Viel, M; Heavens, A; Hähnelt, M G; Kim, T S; Springel, V; Hernquist, L

    2004-01-01

    We present a determination of the bispectrum of the flux in the Lyman-alpha forest of QSO absorption spectra obtained from LUQAS which consists of spectra observed with the high resolution Echelle spectrograph UVES. Typical errors on the observed bispectrum as obtained from a jack-knife estimator are ~ 50%. For wavenumbers in the range 0.03 s/km 2.

  11. VLT/UVES observations of extremely strong intervening damped Lyman-alpha systems: Molecular hydrogen and excited carbon, oxygen and silicon at log N(HI)=22.4

    CERN Document Server

    Noterdaeme, P; Rahmani, H; Petitjean, P; Pâris, I; Ledoux, C; Gupta, N; López, S

    2015-01-01

    We present a detailed analysis of three extremely strong intervening DLAs (log N(HI)>=21.7) observed towards quasars with VLT/UVES. We measure overall metallicities of [Zn/H]~-1.2, -1.3 and -0.7 at respectively zabs=2.34 towards SDSS J2140-0321 (log N(HI) = 22.4+/-0.1), zabs=3.35 towards SDSS J1456+1609 (log N(HI) = 21.7+/-0.1) and zabs=2.25 towards SDSS J0154+1935 (log N(HI) = 21.75+/-0.15). We detect H2 towards J2140-0321 (log N(H2) = 20.13+/-0.07) and J1456+1609 (log N(H2) = 17.10+/-0.09) and argue for a tentative detection towards J0154+1935. Absorption from the excited fine-structure levels of OI, CI and SiII are detected in the system towards J2140-0321, that has the largest HI column density detected so far in an intervening DLA. This is the first detection of OI fine-structure lines in a QSO-DLA, that also provides us a rare possibility to study the chemical abundances of less abundant atoms like Co and Ge. Simple single phase photo-ionisation models fail to reproduce all the observed quantities. Inst...

  12. Empirical classification of VLT/Giraffe stellar spectra in the wavelength range 6440-6810 A in the gamma Vel cluster, and calibration of spectral indices

    CERN Document Server

    Damiani, F; Micela, G; Randich, S; Gilmore, G; Drew, J E; Jeffries, R D; Frémat, Y; Alfaro, E J; Bensby, T; Bragaglia, A; Flaccomio, E; Lanzafame, A C; Pancino, E; Recio-Blanco, A; Sacco, G G; Smiljanic, R; Jackson, R J; de Laverny, P; Morbidelli, L; Worley, C C; Hourihane, A; Costado, M T; Jofré, P; Lind, K; Maiorca, E

    2014-01-01

    We study spectral diagnostics available from optical spectra with R=17000 obtained with the VLT/Giraffe HR15n setup, using observations from the Gaia-ESO Survey, on the gamma Vel young cluster, in order to determine the fundamental parameters of these stars. We define a set of spectroscopic indices, sampling TiO bands, H-alpha core and wings, and many temperature- and gravity-sensitive lines. Combined indices tau (gamma) are also defined as Teff (log g) indicators over a wide spectral-type range. H-alpha emission-line indices are also chromospheric activity or accretion indicators. A metallicity-sensitive index is also defined. These indices enable us to find a clear difference between gravities of main-sequence and pre-main-sequence stars (as well as giant stars): the (gamma,tau) diagram is thus argued to be a promising distance-independent age measurement tool for young clusters. Our indices were quantitatively calibrated by means of photometry and literature reference spectra (from UVES-POP and ELODIE 3.1 ...

  13. The Lyman-alpha forest of a Lyman Break Galaxy VLT Spectra of MS1512-cB58 at z=2.724

    CERN Document Server

    Savaglio, S; Padovani, P

    2001-01-01

    The high redshift galaxy MS1512-cB58 (z=2.724, m_V=20.64) has been observed with the very efficient high resolution echelle spectrograph VLT/UVES. Although this is a very challenging observational program for a Southern hemisphere telescope (the galaxy is located at +36 deg declination), high resolution spectra (FWHM ~ 26 km/s) have revealed, with unprecedented detail along a galaxy sight line, the Lyman-alpha forest due to intervening clouds in the intergalactic medium (IGM). The mean depression D_A due to IGM absorption blueward of the galaxy Ly-alpha wavelength and the number density dn/dz of Ly-alpha clouds have been compared with equivalent results obtained for QSO sight lines at similar redshifts. Our results indicate a possible excess of absorption close to the galaxy. The mean depression at ~ 150 h_65^-1 Mpc comoving (Omega_m=0.3, Omega_Lambda=0.7) from the galaxy is D_A=0.36+/-0.03, to be compared with 0.22+/-0.04, expected from a best fit to QSO sight lines. In the same region (z=2.610), the number ...

  14. RADIAL VELOCITIES FROM VLT-KMOS SPECTRA OF GIANT STARS IN THE GLOBULAR CLUSTER NGC 6388

    Energy Technology Data Exchange (ETDEWEB)

    Lapenna, E.; Mucciarelli, A.; Lanzoni, B.; Ferraro, F. R.; Dalessandro, E. [Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, Viale Berti Pichat 6/2, I-40127 Bologna (Italy); Origlia, L. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani, 1, I-40127 Bologna (Italy); Valenti, E. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München (Germany); Cirasuolo, M. [Institute for Astronomy, University of Edinburgh and STFC, UK Astronomy Technology Center Royal Observatory, Blackford Hill, EH9 3HJ, Edinburgh (United Kingdom)

    2015-01-01

    We present new radial velocity measurements for 82 stars, members of the Galactic globular cluster (GC) NGC 6388, obtained from ESO-VLT K-band Multi Object Spectrograph (KMOS) spectra acquired during the instrument Science Verification. The accuracy of the wavelength calibration is discussed and a number of tests of the KMOS response are presented. The cluster systemic velocity obtained (81.3 ± 1.5 km s{sup –1}) is in very good agreement with previous determinations. While a hint of ordered rotation is found between 9'' and 20'' from the cluster center, where the distribution of radial velocities is clearly bimodal, more data are needed before drawing any firm conclusions. The acquired sample of radial velocities has also been used to determine the cluster velocity dispersion (VD) profile between ∼9'' and 70'', supplementing previous measurements at r < 2'' and r > 60'' obtained with ESO-SINFONI and ESO-FLAMES spectroscopy, respectively. The new portion of the VD profile nicely matches the previous ones, better defining the knee of the distribution. The present work clearly shows the effectiveness of a deployable integral field unit in measuring the radial velocities of individual stars for determining the VD profile of Galactic GCs. It represents the pilot project for an ongoing large program with KMOS and FLAMES at the ESO-VLT, aimed at determining the next generation of VD and rotation profiles for a representative sample of GCs.

  15. Happy Anniversary, VLT !

    Science.gov (United States)

    2004-04-01

    Telescopes (UTs) and will in due time also include four moving 1.8-m Auxiliary Telescopes (ATs), the first one of which successfully passed its first tests in January of this year (see ESO PR 01/04). With unprecedented optical resolution and unsurpassed surface area, the VLT produces extremely sharp images and can record light from the faintest and most remote objects in the Universe. It works at the limit of modern technology, regularly allowing the scientists to peer into new and unknown territories in the immense Universe. Contrary to other large astronomical telescopes, the VLT was designed from the beginning with the use of interferometry as a major goal. For this reason, the four 8.2-m Unit Telescopes were positioned in a quasi-trapezoidal configuration. The light beams from these telescopes, at this moment two-by-two, can be combined in the VLT Interferometer (VLTI). It provides the European scientific community with a ground-based telescope array with collecting power significantly greater than any other facilities available at present or being planned, offering imaging and spectroscopy capabilities at visible and infrared wavelengths. Seven of the planned ten first-generation astronomical instruments are now in operation at the VLT. They cover all major observing modes required to tackle current "hot", front-line research topics: * the multi-mode instrument FORS1 (FOcal Reducer and Spectrograph) and its twin, FORS2, * the Infrared Spectrometer And Array Camera (ISAAC) cryogenic infrared imager and spectrometer, * the UVES (Ultra-violet and Visible Echelle Spectrograph) high-dispersion spectrograph, * the NAOS-CONICA Adaptive Optics facility producing images as sharp as if taken in space [2], * the VIsible Multi-Object Spectrograph (VIMOS) four-channel multiobject spectrograph and imager - allowing to obtain low-resolution spectra of up to 1000 galaxies at a time * the Fibre Large Array Multi-Element Spectrograph (FLAMES) that offers the unique capability to study

  16. The ESO UVES Advanced Data Products Quasar Sample - I. Dataset and New N_HI Measurements of Damped Absorbers

    CERN Document Server

    Zafar, Tayyaba; Peroux, Celine

    2013-01-01

    We present here a dataset of quasars observed with the Ultraviolet Visual Echelle Spectrograph (UVES) on the VLT and available in the ESO UVES Advanced Data Products archive. The sample is made up of a total of 250 high resolution quasar spectra with emission redshifts ranging from 0.191 10^{19} cm^{-2}, which constitutes the sub-damped Lya absorber (sub-DLA) threshold. Within the wavelength coverage of our UVES data, we find 150 damped Lya systems (DLAs)/sub-DLAs in the range 1.5 < z_abs < 4.7. Of these 150, 93 are DLAs and 57 are sub-DLAs. An extensive search in the literature indicates that 6 of these DLAs and 13 of these sub-DLAs have their N_HI measured for the first time. Among them, 10 are new identifications as DLAs/sub-DLAs. For each of these systems, we obtain an accurate measurement of the HI column density and the absorber's redshift in the range 1.7 < z_abs < 4.2 by implementing a Voigt profile-fitting algorithm. These absorbers are further confirmed thanks to the detection of associ...

  17. Early-type stars observed in the ESO UVES Paranal Observatory Project - V. Time-variable interstellar absorption

    CERN Document Server

    McEvoy, Catherine M; Dufton, Philip L; Smith, Keith T; Kennedy, Michael B; Keenan, Francis P; Lambert, David L; Welty, Daniel E; Lauroesch, James T

    2015-01-01

    The structure and properties of the diffuse interstellar medium (ISM) on small scales, sub-au to 1 pc, are poorly understood. We compare interstellar absorption-lines, observed towards a selection of O- and B-type stars at two or more epochs, to search for variations over time caused by the transverse motion of each star combined with changes in the structure in the foreground ISM. Two sets of data were used: 83 VLT- UVES spectra with approximately 6 yr between epochs and 21 McDonald observatory 2.7m telescope echelle spectra with 6 - 20 yr between epochs, over a range of scales from 0 - 360 au. The interstellar absorption-lines observed at the two epochs were subtracted and searched for any residuals due to changes in the foreground ISM. Of the 104 sightlines investigated with typically five or more components in Na I D, possible temporal variation was identified in five UVES spectra (six components), in Ca II, Ca I and/or Na I absorption-lines. The variations detected range from 7\\% to a factor of 3.6 in co...

  18. Modelling telluric line spectra in the optical and infrared with an application to VLT/X-Shooter spectr

    CERN Document Server

    Rudolf, N; Schneider, P C; Schmitt, J H M M

    2016-01-01

    Earth's atmosphere imprints a large number of telluric absorption and emission lines on astronomical spectra, especially in the near infrared, that need to be removed before analysing the affected wavelength regions. These lines are typically removed by comparison to A- or B-type stars used as telluric standards that themselves have strong hydrogen lines, which complicates the removal of telluric lines. We have developed a method to circumvent that problem. For our IDL software package tellrem we used a recent approach to model telluric absorption features with the line-by-line radiative transfer model (LBLRTM). The broad wavelength coverage of the X-Shooter at VLT allows us to expand their technique by determining the abundances of the most important telluric molecules H2O, O2, CO2, and CH4 from sufficiently isolated line groups. For individual observations we construct a telluric absorption model for most of the spectral range that is used to remove the telluric absorption from the object spectrum. We remov...

  19. The UVES Large Program for Testing Fundamental Physics II: Constraints on a Change in {\\mu} Towards Quasar HE 0027-1836

    CERN Document Server

    Rahmani, H; Srianand, R; Noterdaeme, P; Petitjean, P; Molaro, P; Whitmore, J B; Murphy, M T; Centurion, M; Fathivavsari, H; D'Odorico, S; Evans, T M; Levshakov, S A; Lopez, S; Martins, C J A P; Reimers, D; Vladilo, G

    2013-01-01

    We present an accurate analysis of the H2 absorption lines from the zabs ~ 2.4018 damped Ly{\\alpha} system towards HE 0027-1836 observed with the Very Large Telescope Ultraviolet and Visual Echelle Spectrograph (VLT/UVES) as a part of the European Southern Observatory Large Programme "The UVES large programme for testing fundamental physics" to constrain the variation of proton-to-electron mass ratio, {\\mu} = mp/me. We perform cross-correlation analysis between 19 individual exposures taken over three years and the combined spectrum to check the wavelength calibration stability. We notice the presence of a possible wavelength dependent velocity drift especially in the data taken in 2012. We use available asteroids spectra taken with UVES close to our observations to confirm and quantify this effect. We consider single and two component Voigt profiles to model the observed H2 absorption profiles. We use both linear regression analysis and Voigt profile fitting where {\\Delta}{\\mu}/{\\mu} is explicitly considered...

  20. Impact of instrumental systematic errors on fine-structure constant measurements with quasar spectra

    CERN Document Server

    Whitmore, J B

    2014-01-01

    We present a new `supercalibration' technique for measuring systematic distortions in the wavelength scales of high resolution spectrographs. By comparing spectra of `solar twin' stars or asteroids with a reference laboratory solar spectrum, distortions in the standard thorium--argon calibration can be tracked with $\\sim$10\\,m\\,s$^{-1}$ precision over the entire optical wavelength range on scales of both echelle orders ($\\sim$50--100\\,\\AA) and entire spectrographs arms ($\\sim$1000--3000\\,\\AA). Using archival spectra from the past 20 years we have probed the supercalibration history of the VLT--UVES and Keck--HIRES spectrographs. We find that systematic errors in their wavelength scales are ubiquitous and substantial, with long-range distortions varying between typically $\\pm$200\\,m\\,s$^{-1}$\\,per 1000\\,\\AA. We apply a simple model of these distortions to simulated spectra which characterize the large UVES and HIRES quasar samples which previously indicated possible evidence for cosmological variations in the ...

  1. Successful "First Light" for VLT High-Resolution Spectrograph

    Science.gov (United States)

    1999-10-01

    Great Research Prospects with UVES at KUEYEN A major new astronomical instrument for the ESO Very Large Telescope at Paranal (Chile), the UVES high-resolution spectrograph, has just made its first observations of astronomical objects. The astronomers are delighted with the quality of the spectra obtained at this moment of "First Light". Although much fine-tuning still has to be done, this early success promises well for new and exciting science projects with this large European research facility. Astronomical instruments at VLT KUEYEN The second VLT 8.2-m Unit Telescope, KUEYEN ("The Moon" in the Mapuche language), is in the process of being tuned to perfection before it will be "handed" over to the astronomers on April 1, 2000. The testing of the new giant telescope has been successfully completed. The latest pointing tests were very positive and, from real performance measurements covering the entire operating range of the telescope, the overall accuracy on the sky was found to be 0.85 arcsec (the RMS-value). This is an excellent result for any telescope and implies that KUEYEN (as is already the case for ANTU) will be able to acquire its future target objects securely and efficiently, thus saving precious observing time. This work has paved the way for the installation of large astronomical instruments at its three focal positions, all prototype facilities that are capable of catching the light from even very faint and distant celestial objects. The three instruments at KUEYEN are referred to by their acronyms UVES , FORS2 and FLAMES. They are all dedicated to the investigation of the spectroscopic properties of faint stars and galaxies in the Universe. The UVES instrument The first to be installed is the Ultraviolet Visual Echelle Spectrograph (UVES) that was built by ESO, with the collaboration of the Trieste Observatory (Italy) for the control software. Complete tests of its optical and mechanical components, as well as of its CCD detectors and of the complex

  2. Installation and first results of FLAMES, the VLT multifibre facility

    Science.gov (United States)

    Pasquini, Luca; Alonso, Jaime; Avila, Gerardo; Barriga, Pablo; Biereichel, Peter; Buzzoni, Bernard; Cavadore, Cyril; Cumani, Claudio; Dekker, Hans; Delabre, Bernard; Kaufer, Andreas; Kotzlowski, Heinz; Hill, Vanessa; Lizon, Jean-Luis; Nees, Walter; Santin, Paolo; Schmutzer, Ricardo; Kesteren, A. V.; Zoccali, Manuela

    2003-03-01

    FLAMES is the VLT Fibre Facility, installed and being commissioned at the Nasmyth A of UT2 (Kueyen Telescope). FLAMES has been built and assembled at the VLT telescope in about 4 years through an international collaboration between 10 institutes in 6 countries and 3 continents. It had first light with the fibre link to the red arm of UVES on April 1, and with the GIRAFFE spectrograph on July 3. We have not yet enough data to compare the observed vs. expected astronomical performances, although these first data are encouraging in many respects. We aim at proceeding soon with the remaining tests

  3. Exoplanetary atmospheric sodium revealed by the orbital motion. Narrow-band transmission spectroscopy of HD 189733b with UVES

    CERN Document Server

    Khalafinejad, S; Hoeijmakers, H J; Zhou, G; Klocova, T; Schmitt, J H M M; Dreizler, S; Lopez-Morales, M; Husser, T -O; Schmidt, T O B; Collet, R

    2016-01-01

    During primary transits, the spectral signatures of an exoplanet atmosphere can be measured using transmission spectroscopy. The goal of this work is to accurately measure the atomspheric sodium absorption light curve in HD189733b, correcting for the effects of stellar differential limb-darkening, stellar activity and a "bump" caused by the changing radial velocity of the exoplanet. In fact, due to the high cadence and quality of our data, it is the first time that the last feature can be detected even by visual inspection. We use 244 high-resolution optical spectra taken by the UVES instrument mounted at the VLT. Our observations cover a full transit of HD 189733b, with a cadence of 45 seconds. To probe the transmission spectrum of sodium we produce excess light- curves integrating the stellar flux in passbands of 1 \\AA, 1.5 \\AA, and 3 \\AA inside the core of each sodium D-line. We model the effects of external sources on the excess light-curves, which correspond to an observed stellar flare beginning close t...

  4. UVES Analyses the Universe: A First Portfolio of Most Promising Results

    Science.gov (United States)

    2000-04-01

    Astronomers working with a major new instrument at the ESO Very Large Telescope (VLT) at the Paranal Observatory have had a first taste of what is bound to become a research bonanza. Recent test observations with the Ultraviolet-Visual Echelle Spectrograph (UVES) have demonstrated the exceptional science potential of this powerful facility (views from the installation are available as PR Photos 36p-t/99 ). The first long-exposure test spectra of stars, galaxies and quasars obtained with UVES have thrilled the astronomers by their extraordinary quality. Some have already yielded important results, from unprecedentedly accurate chemical analysis of individual stars in nearby galaxies to abundance measurements of light elements created during the Big Bang. Others provide new insights into the composition of the gas in a galaxy in the early Universe, less than 3 billion years after the Big Bang [1]. One particular set of observations measured an upper limit of the uranium content in a very old star - and thereby a lower limit to the age of the universe. UVES starts operations UVES began normal operations on April 1, 2000, at the Nasmyth B focus of KUEYEN , the second 8.2-m VLT Unit Telescope, and it is now fully at the disposal of the scientists. The observing time available until the end of September 2000 was assigned to a large number of front-line research projects by the ESO Observing Programmes Committee. For UVES , as for all other VLT instruments, all observations are executed by ESO staff. In "service observing" mode, they choose the targets from a pre-compiled list, taking into account programme priority and sky conditions. In "visitor mode", the ESO astronomer executes the observations according to the sequence chosen by the visiting astronomer who is also present at the telescope. UVES is the third instrument after FORS1 and ISAAC to enter into regular use at the VLT. It is followed by FORS2 , the second version of FORS that was successfully commissioned

  5. CLASH-VLT: Dissecting the Frontier Fields Galaxy Cluster MACS J0416.1-2403 with $\\sim800$ Spectra of Member Galaxies

    CERN Document Server

    Balestra, I; Sartoris, B; Girardi, M; Grillo, C; Nonino, M; Rosati, P; Biviano, A; Ettori, S; Forman, W; Jones, C; Koekemoer, A; Medezinski, E; Ogrean, G A; Tozzi, P; Umetsu, K; Vanzella, E; van Weeren, R J; Zitrin, A; Annunziatella, M; Caminha, G B; Broadhurst, T; Coe, D; Donahue, M; Fritz, A; Frye, B; Kelson, D; Lombardi, M; Maier, C; Meneghetti, M; Monna, A; Postman, M; Scodeggio, M; Seitz, S; Ziegler, B

    2015-01-01

    We present VIMOS-VLT spectroscopy of the Frontier Fields cluster MACS~J0416.1-2403. Taken as part of the CLASH-VLT survey, the large spectroscopic campaign provided more than 4000 reliable redshifts, including ~800 cluster member galaxies. The unprecedented sample of cluster members at this redshift allows us to perform a highly detailed dynamical and structural analysis of the cluster out to ~3$r_{200}$ (~5Mpc). Our analysis of substructures reveals a complex system composed of a main massive cluster ($M_{200}$~0.9$\\times 10^{15} M_{\\odot}$) presenting two major features: i) a bimodal velocity distribution, showing two central peaks separated by $\\Delta V_{rf}$~1100 km s$^{-1}$ with comparable galaxy content and velocity dispersion, ii) a projected elongation of the main substructures along the NE-SW direction, with a prominent subclump ~600 kpc SW of the center and an isolated BCG approximately halfway between the center and the SW clump. We also detect a low mass structure at z~0.390, ~10' S of the cluster...

  6. UVES Investigates the Environment of a Very Remote Galaxy

    Science.gov (United States)

    2002-03-01

    Surplus of Intergalactic Material May Be Young Supercluster Summary Observations with ESO's Very Large Telescope (VLT) have enabled an international group of astronomers [1] to study in unprecedented detail the surroundings of a very remote galaxy, almost 12 billion light-years distant [2]. The corresponding light travel time means that it is seen at a moment only about 3 billion years after the Big Bang. This galaxy is designated MS 1512-cB58 and is the brightest known at such a large distance and such an early time. This is due to a lucky circumstance: a massive cluster of galaxies ( MS 1512+36 ) is located about halfway along the line-of-sight, at a distance of about 7 billion light-years, and acts as a gravitational "magnifying glass". Thanks to this lensing effect, the image of MS1512-cB58 appears 50 times brighter . Nevertheless, the apparent brightness is still as faint as magnitude 20.6 (i.e., nearly 1 million times fainter than what can be perceived with the unaided eye). Moreover, MS 1512-cB58 is located 36° north of the celestial equator and never rises more than 29° above the horizon at Paranal. It was therefore a great challenge to secure the present observational data with the UVES high-dispersion spectrograph on the 8.2-m VLT KUEYEN telescope . The extremely detailed UVES-spectrum of MS 1512-cB58 displays numerous signatures (absorption lines) of intergalactic gas clouds along the line-of-sight . Some of the clouds are quite close to the galaxy and the astronomers have therefore been able to investigate the distribution of matter in its immediate surroundings. They found an excess of material near MS 1512-cB58, possible evidence of a young supercluster of galaxies , already at this very early epoch. The new observations thus provide an invaluable contribution to current studies of the birth and evolution of structures in the early Universe. This is the first time this kind of observation has ever been done of a galaxy at such a large distance . All

  7. VLT Observations of Turnoff stars in the Globular Cluster NGC 6397

    CERN Document Server

    Thévenin, F; De Pacheco, J A F; Idiart, T P; Jasniewicz, G; De Laverny, P; Plez, B

    2001-01-01

    VLT-UVES high resolution spectra of seven turnoff stars in the metal-poor globular cluster NGC 6397 have been obtained. Atmospheric parameters and abundances of several elements (Li, Na, Mg, Ca, Sc, Ti, Cr, Fe, Ni, Zn and Ba) were derived for program stars. The mean iron abundance is [Fe/H] = -2.02, with no star-to-star variation. The mean abundances of the alpha-elements (Ca, Ti) and of the iron-peak elements (Sc, Cr, Ni) are consistent with abundances derived for field stars of similar metallicity. Magnesium is also almost solar, consistent with the values found by Idiart & Th\\'evenin (2000) when non-LTE effects (NLTE hereafter) are taken into account. The sodium abundance derived for five stars is essentially solar, but one object (A447) is clearly Na deficient. These results are compatible with the expected abundance range estimated from the stochastic evolutionary halo model by Argast et al. (2000) when at the epoch of [Fe/H] $\\sim$ -2 the interstellar medium is supposed to become well-mixed.

  8. Domain wall signatures in BICEP2, Planck, VLT/UVES and Keck/HIRES data?

    CERN Document Server

    Avelino, P P

    2014-01-01

    We consider the possibility that current hints for a spatial variation of the fine structure constant at high redshift could be due to a domain wall network described by a scalar field non-minimally coupled to the electromagnetic field. We show that in order to be cause of the reported spatial variation of the fine structure constant, without being in conflict with the observed anisotropies of the cosmic microwave background, the characteristic scale of the network would have to be of the order of the Hubble radius and the fractional contribution of the domain wall network to the energy density of the Universe would need to be in the range $10^{-10} < \\Omega_{w0} < 10^{-5}$. We argue that for sufficiently large values of $\\Omega_{w0}$ in this range, domain walls could even be responsible for the large scale anomalies in the temperature distribution of the cosmic microwave background detected by Planck and WMAP and for the B-mode polarisation signature detected by BICEP2. Since the domain wall contributi...

  9. The AVES adaptive optics spectrograph for the VLT: status report

    Science.gov (United States)

    Pallavicini, Roberto; Delabre, Bernard; Pasquini, Luca; Zerbi, Filippo M.; Bonanno, Giovanni; Comari, Maurizio; Conconi, Paolo; Mazzoleni, Ruben; Santin, Paolo; Damiani, Francesco; Di Marcantonio, Paolo; Franchini, Mariagrazia; Spano, Paolo; Bonifacio, P.; Catalano, Santo; Molaro, Paolo P.; Randich, S.; Rodono, Marcello

    2003-03-01

    We report on the status of AVES, the Adaptive-optics Visual Echelle Spectrograph proposed for the secondary port of the Nasmyth Adaptive Optics System (NAOS) recently installed at the VLT. AVES is an intermediate resolution (R ≍ 16,000) high-efficiency fixed- format echelle spectrograph which operates in the spectral band 500 - 1,000 nm. In addition to a high intrinsic efficiency, comparable to that of ESI at Keck II, it takes advantage of the adaptive optics correction provided by NAOS to reduce the sky and detector contribution in background-limited observations of weak sources, thus allowing a further magnitude gain with respect to comparable non-adaptive optics spectrographs. Simulations show that the instrument will be capable of reaching a magnitude V = 22.5 at S/N > 10 in two hours, two magnitudes weaker than GIRAFFE at the same resolution and 3 magnitudes weaker than the higher resolution UVES spectrograph. Imaging and coronographic functions have also been implemented in the design. We present the results of the final design study and we dicuss the technical and operational issues related to its implementation at the VLT as a visitor instrument. We also discuss the possibility of using a scaled-up non-adaptive optics version of the same design as an element of a double- or triple-arm intermediate-resolution spectrograph for the VLT. Such an option looks attractive in the context of a high-efficiency large-bandwidth (320 - 1,500 nm) spectrograph ("fast-shooter") being considered by ESO as a 2nd-generation VLT instrument.

  10. Alternative Data Reduction Procedures for UVES: Wavelength Calibration and Spectrum Addition

    CERN Document Server

    Thompson, Rodger I; Black, John H; Martins, C J A P

    2008-01-01

    This paper addresses alternative procedures to the ESO supplied pipeline procedures for the reduction of UVES spectra of two quasar spectra to determine the value of the fundamental constant mu = Mp/Me at early times in the universe. The procedures utilize intermediate product images and spectra produced by the pipeline with alternative wavelength calibration and spectrum addition methods. Spectroscopic studies that require extreme wavelength precision need customized wavelength calibration procedures beyond that usually supplied by the standard data reduction pipelines. An example of such studies is the measurement of the values of the fundamental constants at early times in the universe. This article describes a wavelength calibration procedure for the UV-Visual Echelle Spectrometer on the Very Large Telescope, however, it can be extended to other spectrometers as well. The procedure described here provides relative wavelength precision of better than 3E-7 for the long-slit Thorium-Argon calibration lamp ex...

  11. VLT Observations Confirm that the Universe Was Hotter in the Past

    Science.gov (United States)

    2000-12-01

    . However, slight temperature variations in different directions have been measured, most recently by means of detailed observations from a balloon above Antarctica (the Boomerang experiment). Since the universe is expanding, it must have been denser in the past. A particular prediction of the Big Bang theory is also that the temperature of the CMBR must have been higher at earlier times. However, although quite a few attempts have been made, no clear observational confirmation of this has been possible so far. In fact, the best observations until now have only been able to establish upper limits to the cosmic temperature at earlier epochs. But proof is now available from new observations carried out with the Ultra-violet and Visual Echelle Spectrograph (UVES) at the 8.2-m VLT KUEYEN telescope on Paranal . Very demanding observations The further we look out into the Universe, the further we look back in time. It was actually suggested more than 30 years ago that the predicted increase of temperature with distance (redshift) could be tested by observing specific absorption lines in the spectra of distant quasars. The idea is simply that at earlier epochs, the CMBR was hot enough to excite certain atomic levels, and thus to give rise to particular absorption lines in the spectrum of a celestial object. Some faint absorption lines of neutral carbon atoms were found to be especially promising, in the sense that they were predicted to be very sensitive to the surrounding temperature. However, previous generations of (smaller) astronomical telescopes were unable to achieve spectra of sufficient quality of these faint absorption lines in faint and remote objects in the distant (i.e., early) Universe. The need to isolate the CMBR effects The advent of 8-m class telescopes has now changed this situation. A few years ago, the 10-m Keck telescope (Mauna Kea, Hawaii, USA) obtained a spectrum of a quasar that was sufficiently detailed to determine an upper limit to the temperature of

  12. VLT Data Flow System Begins Operation

    Science.gov (United States)

    1999-06-01

    Building a Terabyte Archive at the ESO Headquarters The ESO Very Large Telescope (VLT) is the sum of many sophisticated parts. The site at Cerro Paranal in the dry Atacama desert in Northern Chile is one of the best locations for astronomical observations from the surface of the Earth. Each of the four 8.2-m telescopes is a technological marvel with self-adjusting optics placed in a gigantic mechanical structure of the utmost precision, continuously controlled by advanced soft- and hardware. A multitude of extremely complex instruments with sensitive detectors capture the faint light from distant objects in the Universe and record the digital data fast and efficiently as images and spectra, with a minimum of induced noise. And now the next crucial link in this chain is in place. A few nights ago, following an extended test period, the VLT Data Flow System began providing the astronomers with a steady stream of high-quality, calibrated image and spectral data, ready to be interpreted. The VLT project has entered into a new phase with a larger degree of automation. Indeed, the first 8.2-m Unit Telescope, ANTU, with the FORS1 and ISAAC instruments, has now become a true astronomy machine . A smooth flow of data through the entire system ESO PR Photo 25a/99 ESO PR Photo 25a/99 [Preview - JPEG: 400 x 292 pix - 104k] [Normal - JPEG: 800 x 584 pix - 264k] [High-Res - JPEG: 3000 x 2189 pix - 1.5M] Caption to ESO PR Photo 25a/99 : Simplified flow diagramme for the VLT Data Flow System . It is a closed-loop software system which incorporates various subsystems that track the flow of data all the way from the submission of proposals to storage of the acquired data in the VLT Science Archive Facility. The DFS main components are: Program Handling, Observation Handling, Telescope Control System, Science Archive, Pipeline and Quality Control. Arrows indicate lines of feedback. Already from the start of this project more than ten years ago, the ESO Very Large Telescope was

  13. Multiple Eyes for the VLT

    Science.gov (United States)

    2002-01-01

    First System of Deployable Multi-Integral Field Units Ready Summary The ESO Very Large Telescope (VLT) at the Paranal Observatory is being equipped with many state-of-the-art astronomical instruments that will allow observations in a large number of different modes and wavebands. Soon to come is the Fibre Large Array Multi-Element Spectrograph (FLAMES) , a project co-ordinated by ESO. It incorporates several complex components, now being constructed at various research institutions in Europe and Australia. One of these, a true technological feat, is a unique system of 15 deployable fibre bundles, the so-called Integral Field Units (IFUs) . They can be accurately positioned within a sky field-of-view measuring no less that 25 arcmin in diameter, i.e., almost as large as the full Moon . Each of the IFUs looks like an insect's eye and images a small sky area (3 x 2 arcsec 2 ) with a multiple microlens. From each IFU, 20 narrow light beams are sent via optical fibres to an advanced spectrograph. All 300 spectra are recorded simultaneously by a sensitive digital camera. A major advantage of this technique is that, contrary usual spectroscopic observations in which spectral information is obtained along a (one-dimensional) line on the sky, it now allows (two-dimensional) area spectroscopy . This will permit extremely efficient spectral observations of many celestial objects, including faint galaxies, providing detailed information about their internal structure and motions. Such studies will have an important impact on our understanding, e.g., of the early evolution of galaxies , the main building blocks in the Universe. The IFUs have been developed by a team of astronomers and engineers [2] at the Observatoire de Paris-Meudon. All IFU components are now at the ESO Headquarters in Garching (Germany) where they are being checked and integrated into the instrument [3]. PR Photo 03a/02 : The GIRAFFE spectrograph in the ESO Assembly Hall (Garching, Germany) . PR Photo 03b/02

  14. [Determination of soluble solids content in Nanfeng Mandarin by Vis/NIR spectroscopy and UVE-ICA-LS-SVM].

    Science.gov (United States)

    Sun, Tong; Xu, Wen-Li; Hu, Tian; Liu, Mu-Hua

    2013-12-01

    The objective of the present research was to assess soluble solids content (SSC) of Nanfeng mandarin by visible/near infrared (Vis/NIR) spectroscopy combined with new variable selection method, simplify prediction model and improve the performance of prediction model for SSC of Nanfeng mandarin. A total of 300 Nanfeng mandarin samples were used, the numbers of Nanfeng mandarin samples in calibration, validation and prediction sets were 150, 75 and 75, respectively. Vis/NIR spectra of Nanfeng mandarin samples were acquired by a QualitySpec spectrometer in the wavelength range of 350-1000 nm. Uninformative variables elimination (UVE) was used to eliminate wavelength variables that had few information of SSC, then independent component analysis (ICA) was used to extract independent components (ICs) from spectra that eliminated uninformative wavelength variables. At last, least squares support vector machine (LS-SVM) was used to develop calibration models for SSC of Nanfeng mandarin using extracted ICs, and 75 prediction samples that had not been used for model development were used to evaluate the performance of SSC model of Nanfeng mandarin. The results indicate t hat Vis/NIR spectroscopy combinedwith UVE-ICA-LS-SVM is suitable for assessing SSC o f Nanfeng mandarin, and t he precision o f prediction ishigh. UVE--ICA is an effective method to eliminate uninformative wavelength variables, extract important spectral information, simplify prediction model and improve the performance of prediction model. The SSC model developed by UVE-ICA-LS-SVM is superior to that developed by PLS, PCA-LS-SVM or ICA-LS-SVM, and the coefficient of determination and root mean square error in calibration, validation and prediction sets were 0.978, 0.230%, 0.965, 0.301% and 0.967, 0.292%, respectively.

  15. UVES and X-Shooter spectroscopy of the emission line AM CVn systems GP Com and V396 Hya

    CERN Document Server

    Kupfer, T; Groot, P J; Marsh, T R; Nelemans, G; Roelofs, G H A

    2016-01-01

    We present time-resolved spectroscopy of the AM CVn-type binaries GP Com and V396 Hya obtained with VLT/X-Shooter and VLT/UVES. We fully resolve the narrow central components of the dominant helium lines and determine radial velocity semi-amplitudes of $K_{\\rm spike} = 11.7\\pm0.3$ km s$^{-1}$ for GP Com and $K_{\\rm spike} = 5.8\\pm0.3$ km s$^{-1}$ for V396 Hya. The mean velocities of the narrow central components show variations from line to line. Compared to calculated line profiles that include Stark broadening we are able to explain the displacements, and the appearance of forbidden helium lines, by additional Stark broadening of emission in a helium plasma with an electron density $n_e\\simeq 5\\times 10^{15}$ cm$^{-3}$. More than $30$ nitrogen and more than $10$ neon lines emission lines were detected in both systems. Additionally, $20$ nitrogen absorption lines are only seen in GP Com. The radial velocity variations of these lines show the same phase and velocity amplitude as the central helium emission co...

  16. ESO-VLT Science Data Processing

    Science.gov (United States)

    Hanuschik, Reinhard; Data Processing; Quality Control Group

    2017-09-01

    "In the past three years the QC group at ESO has installed an efficient process to create science-grade data products from VLT instruments. With the focus on spectroscopic observations, these data products are complementary to the (externally provided) data products from the surveys. The production line combines efficient mass production (more than one million spectra have been generated so far), previews, and quality control. All data products are available to the community through the ESO archive interface. The talk will highlight the most recent addition, the MUSE datacubes."

  17. UVES Abundances of Stars in Nearby Dwarf Spheroidal Galaxies

    Science.gov (United States)

    Tolstoy, Eline; Venn, Kim; Shetrone, Matt; Primas, Francesca; Hill, Vanessa; Kaufer, Andreas; Szeifert, Thomas

    2002-07-01

    It is a truth universally acknowledged, that a galaxy in possession of a good quantity of gas must want to form stars. It is the details of how and why that baffle us all. The simplest theories either would have this process a carefully self-regulated affair, or one that goes completely out of control and is capable of wrecking the galaxy which hosts it. Of course the majority of galaxies seem to amble along somewhere between these two extremes, and the mean properties tend to favour a quiescent self-regulated evolutionary scenario. But there area variety of observations which require us to invoke transitory ‘bursts’ of star-formation at one time or another in most galaxy types. Several nearby dwarf spheroidal galaxies have clearly determined star-formation histories with apparent periods of zero star formation followed by periods of fairly active star formation. If we are able to understand what separated these bursts we would understand several important phenomena in galaxy evolution. Were these galaxies able to clear out their gas reservoir in a burst of star formation? How did this gas return? or did it? Have these galaxies receieved gas from the IGM instead? Could stars from these types of galaxy contribute significantly to the halo population in our Galaxy? To answer these questions we need to combine accurate stellar photometry and Colour-Magnitude Diagram interpretation with detailed metal abundances to combine a star-formation rate versus time with a range of element abundances with time. Different elements trace different evolutionary process (e.g., relative contributions of type I and II supernovae). We often aren't even sure of the abundance spread in these galaxies. We have collected detailed high resolution UVES spectra of four nearby dwarf spheroidal galaxies (Sculptor, Fornax, Leo I & Carina) to begin to answer these questions. This is a precursor study to a more complete study with FLAMES. We presented at this meeting the initial results for

  18. 9 Sgr spectra 1999-2011 (Rauw+, 2012)

    NARCIS (Netherlands)

    G. Rauw; H. Sana; M. Spano; E. Gosset; L. Mahy; M. De Becker; P. Eenens

    2012-01-01

    The best quality wavelength-calibrated and normalized spectra of 9 Sgr are provided. These data were obtained with the FEROS, UVES and Coralie spectrographs. The wavelengths are given in the heliocentric frame of reference.

  19. VLT Instruments Pipeline System Overview

    Science.gov (United States)

    Jung, Y.; Ballester, P.; Banse, K.; Hummel, W.; Izzo, C.; McKay, D. J.; Kiesgen, M.; Lundin, L. K.; Modigliani, A.; Palsa, R. M.; Sabet, C.

    2004-07-01

    Since the beginning of the VLT operations in 1998, substantial effort has been put in the development of automatic data reduction tools for the VLT instruments. A VLT instrument pipeline is a complex system that has to be able to identify and classify each produced FITS file, optionally retrieve calibration files from a database, use an image processing software to reduce the data, compute and log quality control parameters, produce FITS images or tables with the correct headers, optionally display them in the control room and send them to the archive. Each instrument has its own dedicated pipeline, based on a common infrastructure and installed with the VLT Data Flow System (DFS). With the increase in the number and the complexity of supported instruments and in the rate of produced data, these pipelines are becoming vital for both the VLT operations and the users, and request more and more resources for development and maintenance. This paper describes the different pipeline tasks with some real examples. It also explains how the development process has been improved to both decrease its cost and increase the pipelines quality using the lessons learned from the first instruments pipelines development.

  20. The red dwarf pair GJ65 AB: inflated, spinning twins of Proxima. Fundamental parameters from PIONIER, NACO, and UVES observations

    Science.gov (United States)

    Kervella, P.; Mérand, A.; Ledoux, C.; Demory, B.-O.; Le Bouquin, J.-B.

    2016-10-01

    The nearby red dwarf binary GJ65 AB (UV+BL Ceti, M5.5Ve+M6Ve) is a cornerstone system to probe the physics of very low-mass stars. The radii of the two stars are currently known only from indirect photometric estimates, however, and this prevents us from using GJ65 AB as calibrators for the mass-radius (M-R) relation. We present new interferometric measurements of the angular diameters of the two components of GJ65 with the VLTI/PIONIER instrument in the near-infrared H band: θUD(A) = 0.558 ± 0.008 ± 0.020 mas and θUD(B) = 0.539 ± 0.009 ± 0.020 mas. They translate into limb-darkened angular diameters of θLD(A) = 0.573 ± 0.021 mas and θLD(B) = 0.554 ± 0.022 mas. Based on the known parallax, the linear radii are R(A) = 0.165 ± 0.006 R⊙ and R(B) = 0.159 ± 0.006 R⊙ (σ(R) /R = 4%). We searched for the signature of flares and faint companions in the interferometric visibilities and closure phases, but we did not identify any significant signal. We also observed GJ65 with the VLT/NACO adaptive optics and refined the orbital parameters and infrared magnitudes of the system. We derived masses for the two components of m(A) = 0.1225 ± 0.0043 M⊙ and m(B) = 0.1195 ± 0.0043 M⊙ (σ(m) /m = 4%). To derive the radial and rotational velocities of the two stars as well as their relative metallicity with respect to Proxima, we also present new individual UVES high-resolution spectra of the two components. Placing GJ65 A and B in the mass-radius diagram shows that their radii exceed expectations from recent models by 14 ± 4% and 12 ± 4%, respectively. Following previous theories, we propose that this discrepancy is caused by the inhibition of convective energy transport by a strong internal magnetic field generated by dynamo effect in these two fast-rotating stars. A comparison with the almost identical twin Proxima, which is rotating slowly, strengthens this hypothesis because the radius of Proxima does not appear to be inflated compared to models. Based on

  1. The VLT FLAMES Tarantula Survey

    NARCIS (Netherlands)

    Evans, C.; Taylor, W.; Sana, H.; Hénault-Brunet, V.; Bagnoli, T.; Bastian, N.; Bestenlehner, J.; Bonanos, A.; Bressert, E.; Brott, I.; Campbell, M.; Cantiello, M.; Carraro, G.; Clark, S.; Costa, E.; Crowther, P.; de Koter, A.; de Mink, S.; Doran, E.; Dufton, P.; Dunstall, P.; Garcia, M.; Gieles, M.; Gräfener, G.; Herrero, A.; Howarth, I.; Izzard, R.; Köhler, K.; Langer, N.; Lennon, D.; Maíz Apellániz, J.; Markova, N.; Najarro, P.; Puls, J.; Ramirez, O.; Sabín-Sanjulián, C.; Simón-Díaz, S.; Smartt, S.; Stroud, V.; van Loon, J.; Vink, J.S.; Walborn, N.

    2011-01-01

    We introduce the VLT FLAMES Tarantula Survey, an ESO Large Programme from which we have obtained optical spectroscopy of over 800 massive stars in the spectacular 30 Doradus region of the Large Magellanic Cloud. A key feature is the use of multi-epoch observations to provide strong constraints on

  2. Time variations of narrow absorption lines in high resolution quasar spectra

    CERN Document Server

    Boissé, P; Prochaska, J X; Péroux, C; York, D G

    2015-01-01

    Aims. We have searched for temporal variations of narrow absorption lines in high resolution quasar spectra. A sample of 5 distant sources have been assembled, for which 2 spectra - VLT/UVES or Keck/HIRES - taken several years apart are available. Methods. We first investigate under which conditions variations in absorption line profiles can be detected reliably from high resolution spectra, and discuss the implications of changes in terms of small-scale structure within the intervening gas or intrinsic origin. The targets selected allow us to investigate the time behavior of a broad variety of absorption line systems, sampling diverse environments: the vicinity of active nuclei, galaxy halos, molecular-rich galaxy disks associated with damped Lya systems, as well as neutral gas within our own Galaxy. Results. Absorption lines from MgII, FeII or proxy species with lines of lower opacity tracing the same kind of gas appear to be remarkably stable (1 sigma upper limits as low as 10 % for some components on scal...

  3. The COS/UVES Absorption Survey of the Magellanic Stream: II. Evidence for a complex enrichment history of the Stream from the Fairall 9 sightline

    CERN Document Server

    Richter, Philipp; Wakker, Bart P; Lehner, Nicolas; Howk, J Christopher; Bland-Hawthorn, Joss; Bekhti, Nadya Ben; Fechner, Cora

    2013-01-01

    We present a multi-wavelength study of the Magellanic Stream (MS), a massive gaseous structure in the Local Group that is believed to represent material stripped from the Magellanic Clouds. We use ultraviolet, optical and radio data obtained with HST/COS, VLT/UVES, FUSE and GASS to study metal abundances and physical conditions in the Stream toward the quasar Fairall 9. Line absorption in the MS is detected from a large number of metal ions and from molecular hydrogen. From the analysis of unsaturated SII absorption, in combination with a detailed photoionization model, we obtain a surprisingly high alpha abundance in the Stream toward Fairall 9 of [S/H]=-0.30pm0.04 (0.5 solar). This value is 5 times higher than what is found along other MS sightlines based on similar COS/UVES data sets. In contrast, the measured nitrogen abundance is found to be substantially lower ([N/H]=-1.15pm0.06), implying a very low [alpha/N] ratio of -0.85 dex. The substantial differences in the chemical composition of the Magellanic ...

  4. Atomic Diffusion and Mixing in Old Stars I. VLT/FLAMES-UVES Observations of Stars in NGC 6397

    CERN Document Server

    Korn, A J; Richard, O; Barklem, P S; Mashonkina, L; Collet, R; Gustafsson, B; Piskunov, N

    2007-01-01

    We present a homogeneous photometric and spectroscopic analysis of 18 stars along the evolutionary sequence of the metal-poor globular cluster NGC 6397 ([Fe/H] = -2), from the main-sequence turnoff point to red giants below the bump. The spectroscopic stellar parameters, in particular stellar-parameter differences between groups of stars, are in good agreement with broad-band and Stroemgren photometry calibrated on the infrared-flux method. The spectroscopic abundance analysis reveals, for the first time, systematic trends of iron abundance with evolutionary stage. Iron is found to be 31% less abundant in the turnoff-point stars than in the red giants. An abundance difference in lithium is seen between the turnoff-point and warm subgiant stars. The impact of potential systematic errors on these abundance trends (stellar parameters, the hydrostatic and LTE approximations) is quantitatively evaluated and found not to alter our conclusions significantly. Trends for various elements (Li, Mg, Ca, Ti and Fe) are co...

  5. UVES and X-Shooter spectroscopy of the emission line AM CVn systems GP Com and V396 Hya

    Science.gov (United States)

    Kupfer, T.; Steeghs, D.; Groot, P. J.; Marsh, T. R.; Nelemans, G.; Roelofs, G. H. A.

    2016-04-01

    We present time-resolved spectroscopy of the AM CVn-type binaries GP Com and V396 Hya obtained with VLT/X-Shooter and VLT/UV-Visual Echelle Spectrograph (UVES). We fully resolve the narrow central components of the dominant helium lines and determine radial velocity semi-amplitudes of Kspike = 11.7 ± 0.3 km s-1 for GP Com and Kspike = 5.8 ± 0.3 km s-1 for V396 Hya. The mean velocities of the narrow central components show variations from line to line. Compared to calculated line profiles that include Stark broadening we are able to explain the displacements, and the appearance of forbidden helium lines, by additional Stark broadening of emission in a helium plasma with an electron density ne ≃ 5 × 1015 cm-3. More than 30 nitrogen and more than 10 neon lines emission lines were detected in both systems. Additionally, 20 nitrogen absorption lines are only seen in GP Com. The radial velocity variations of these lines show the same phase and velocity amplitude as the central helium emission components. The small semi-amplitude of the central helium emission component, the consistency of phase and amplitude with the absorption components in GP Com as well as the measured Stark effect shows that the central helium emission component, the so-called central-spike, is consistent with an origin on the accreting white dwarf. We use the dynamics of the bright spot and the central-spike to constrain the binary parameters for both systems and find a donor mass of 9.6-42.8 MJupiter for GP Com and 6.1-30.5 MJupiter for V396 Hya. We find an upper limit for the rotational velocity of the accretor of vrot < 46 km s-1 for GP Com and vrot < 59 km s-1 for V396 Hya which excludes a fast rotating accretor in both systems.

  6. The VLT Real Time Display

    Science.gov (United States)

    Herlin, T.; Brighton, A.; Biereichel, P.

    The VLT Real-Time Display (RTD) software was developed in order to support image display in real-time, providing a tool for users to display video like images from a camera or detector as fast as possible on an X-Server. The RTD software is implemented as a package providing a Tcl/Tk image widget written in C++ and an independent image handling library and can be used as a building block, adding display capabilities to dedicated VLT control applications. The RTD widget provides basic image display functionality like: panning, zooming, color scaling, colormaps, intensity changes, pixel query, overlaying of line graphics. A large set of assisting widgets, e.g., colorbar, zoom window, spectrum plot are provided to enable the building of image applications. The support for real-time is provided by an RTD image event mechanism used for camera or detector subsystems to pass images to the RTD widget. Image data are passed efficiently via shared memory. This paper describes the architecture of the RTD software and summarizes the features provided by RTD.

  7. VLT spectroscopy of NGC3115 globular clusters

    CERN Document Server

    Kuntschner, H; Sharples, R M; Worthey, G; Fricke, K J; Kuntschner, Harald; Ziegler, Bodo L.; Worthey, Guy; Fricke, Klaus J.

    2002-01-01

    We present results derived from VLT-FORS2 spectra of 24 different globular clusters associated with the lenticular galaxy NGC3115. A subsample of 17 globular clusters have sufficiently high signal-to-noise to allow precision measurements of absorption line-strengths. Comparing these indices to new stellar population models by Thomas et al. we determine ages, metallicities and element abundance ratios. Our data are also compared with the Lick/IDS observations of Milky Way and M31 globular clusters. Unpublished higher order Balmer lines (HgammaA,F and HdeltaA,F) from the Lick/IDS observations are given in the Appendix. Our best age estimates show that the observed clusters which sample the bimodal colour distribution of NGC3115 are coeval within our observational errors (2-3 Gyr). Our best calibrated age/metallicity diagnostic diagram (Hbeta vs [MgFe]) indicates an absolute age of 11-12 Gyr. We confirm with our accurate line-strength measurements that the (V-I) colour is a good metallicity indicator within the ...

  8. VLT laser guide star facility

    Science.gov (United States)

    Bonaccini, Domenico; Allaert, Eric; Araujo, Constanza; Brunetto, Enzo; Buzzoni, Bernard; Comin, Mauro; Cullum, Martin J.; Davies, Richard I.; Dichirico, Canio; Dierickx, Philippe; Dimmler, Martin; Duchateau, Michel; Egedal, Carsten; Hackenberg, Wolfgang K. P.; Hippler, Stefan; Kellner, Stefan; van Kesteren, Arno; Koch, Franz; Neumann, Udo; Ott, Thomas; Quattri, Marco; Quentin, Jutta; Rabien, Sebastian; Tamai, Roberto; Tapia, Mario; Tarenghi, Massimo

    2003-02-01

    We report on the ongoing VLT Laser Guide Star Facility project, which will allow the ESO UT4 telescope to produce an artificial reference star for the Adaptive Optics systems NAOS-CONICA and SINFONI. A custom developed dye laser producing >10W CW at 589nm is installed on-board of the UT4 telescope, then relayed by means of a single mode optical fiber behind the secondary mirror, where a 500mm diameter lightweight, f/1 launch telescope is projecting the laser beam at 90 km altitude. We described the design tradeoffs and provide some details of the chosen subsystems. This paper is an update including subsystems results, to be read together with our previous paper on LGSF design description.

  9. THE COS/UVES ABSORPTION SURVEY OF THE MAGELLANIC STREAM. II. EVIDENCE FOR A COMPLEX ENRICHMENT HISTORY OF THE STREAM FROM THE FAIRALL 9 SIGHTLINE

    Energy Technology Data Exchange (ETDEWEB)

    Richter, Philipp; Fechner, Cora [Institut fuer Physik und Astronomie, Universitaet Potsdam, Haus 28, Karl-Liebknecht-Str. 24/25, D-14476 Golm (Potsdam) (Germany); Fox, Andrew J. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Wakker, Bart P. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Lehner, Nicolas; Howk, J. Christopher [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Bland-Hawthorn, Joss [Institute of Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Ben Bekhti, Nadya [Argelander-Institut fuer Astronomie, Universitaet Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany)

    2013-08-01

    We present a multi-wavelength study of the Magellanic Stream (MS), a massive gaseous structure in the Local Group that is believed to represent material stripped from the Magellanic Clouds. We use ultraviolet, optical and radio data obtained with HST/COS, VLT/UVES, FUSE, GASS, and ATCA to study metal abundances and physical conditions in the Stream toward the quasar Fairall 9. Line absorption in the MS from a large number of metal ions and from molecular hydrogen is detected in up to seven absorption components, indicating the presence of multi-phase gas. From the analysis of unsaturated S II absorption, in combination with a detailed photoionization model, we obtain a surprisingly high {alpha} abundance in the Stream toward Fairall 9 of [S/H] = -0.30 {+-} 0.04 (0.50 solar). This value is five times higher than what is found along other MS sightlines based on similar COS/UVES data sets. In contrast, the measured nitrogen abundance is found to be substantially lower ([N/H] = -1.15 {+-} 0.06), implying a very low [N/{alpha}] ratio of -0.85 dex. The substantial differences in the chemical composition of MS toward Fairall 9 compared to other sightlines point toward a complex enrichment history of the Stream. We favor a scenario, in which the gas toward Fairall 9 was locally enriched with {alpha} elements by massive stars and then was separated from the Magellanic Clouds before the delayed nitrogen enrichment from intermediate-mass stars could set in. Our results support (but do not require) the idea that there is a metal-enriched filament in the Stream toward Fairall 9 that originates in the LMC.

  10. The Uve1 endonuclease is regulated by the white collar complex to protect cryptococcus neoformans from UV damage.

    Directory of Open Access Journals (Sweden)

    Surbhi Verma

    Full Text Available The pathogenic fungus Cryptococcus neoformans uses the Bwc1-Bwc2 photoreceptor complex to regulate mating in response to light, virulence and ultraviolet radiation tolerance. How the complex controls these functions is unclear. Here, we identify and characterize a gene in Cryptococcus, UVE1, whose mutation leads to a UV hypersensitive phenotype. The homologous gene in fission yeast Schizosaccharomyces pombe encodes an apurinic/apyrimidinic endonuclease acting in the UVDE-dependent excision repair (UVER pathway. C. neoformans UVE1 complements a S. pombe uvde knockout strain. UVE1 is photoregulated in a Bwc1-dependent manner in Cryptococcus, and in Neurospora crassa and Phycomyces blakesleeanus that are species that represent two other major lineages in the fungi. Overexpression of UVE1 in bwc1 mutants rescues their UV sensitivity phenotype and gel mobility shift experiments show binding of Bwc2 to the UVE1 promoter, indicating that UVE1 is a direct downstream target for the Bwc1-Bwc2 complex. Uve1-GFP fusions localize to the mitochondria. Repair of UV-induced damage to the mitochondria is delayed in the uve1 mutant strain. Thus, in C. neoformans UVE1 is a key gene regulated in response to light that is responsible for tolerance to UV stress for protection of the mitochondrial genome.

  11. VIMOS - a Cosmology Machine for the VLT

    Science.gov (United States)

    2002-03-01

    Successful Test Observations With Powerful New Instrument at Paranal [1] Summary One of the most fundamental tasks of modern astrophysics is the study of the evolution of the Universe . This is a daunting undertaking that requires extensive observations of large samples of objects in order to produce reasonably detailed maps of the distribution of galaxies in the Universe and to perform statistical analysis. Much effort is now being put into mapping the relatively nearby space and thereby to learn how the Universe looks today . But to study its evolution, we must compare this with how it looked when it still was young . This is possible, because astronomers can "look back in time" by studying remote objects - the larger their distance, the longer the light we now observe has been underway to us, and the longer is thus the corresponding "look-back time". This may sound easy, but it is not. Very distant objects are very dim and can only be observed with large telescopes. Looking at one object at a time would make such a study extremely time-consuming and, in practical terms, impossible. To do it anyhow, we need the largest possible telescope with a highly specialised, exceedingly sensitive instrument that is able to observe a very large number of (faint) objects in the remote universe simultaneously . The VLT VIsible Multi-Object Spectrograph (VIMOS) is such an instrument. It can obtain many hundreds of spectra of individual galaxies in the shortest possible time; in fact, in one special observing mode, up to 6400 spectra of the galaxies in a remote cluster during a single exposure, augmenting the data gathering power of the telescope by the same proportion. This marvellous science machine has just been installed at the 8.2-m MELIPAL telescope, the third unit of the Very Large Telescope (VLT) at the ESO Paranal Observatory. A main task will be to carry out 3-dimensional mapping of the distant Universe from which we can learn its large-scale structure . "First light

  12. Toward accurate radial velocities with the fiber-fed GIRAFFE multi-object VLT spectrograph

    Science.gov (United States)

    Royer, Frederic; Blecha, Andre; North, Pierre; Simond, Gilles; Baratchart, Sebastien; Cayatte, Veronique; Chemin, Laurent; Palsa, Ralf

    2002-12-01

    We describe briefly the Data-Reduction of the VLT fiber-fed multi-object GIRAFFE spectrograph - part of the VLT FLAMES facility. We focus on specific features of GIRAFFE - the simultaneous wavelength calibration - and their impact on the data-reduction strategy. We describe the implementation of the global physical model and we compare the results obtained with the simulated, laboratory and preliminary data. We discuss the influence of critical parameters, the overall accuracy of the wavelength solution, and the stability and the robustness of the global model approach. We address the accuracy of radial velocity measurements illustrated by solar spectra obtained during the Preliminary Acceptance in Europe.

  13. The Origin and Evolution of the Halo PN BoBn 1: From a Viewpoint of Chemical Abundances Based on Multiwavelength Spectra

    CERN Document Server

    Otsuka, M; Hyung, S; Izumiura, H; STScI,; Telescope/NAOJ, Subaru; University, Chungbuk National; Observatory/NAOJ, Okayama Astrophysical

    2010-01-01

    We have performed a comprehensive chemical abundance analysis of the extremely metal-poor ([Ar/H]<-2) halo planetary nebula (PN) BoBn 1 based on IUE archive data, Subaru/HDS spectra, VLT/UVES archive data, and Spitzer/IRS spectra. We have detected over 600 lines in total and calculated ionic and elemental abundances of 13 elements using detected optical recombination lines (ORLs) and collisionally excited lines (CELs). The estimations of C, N, O, and Ne abundances from the ORLs and Kr, Xe, and Ba from the CELs are done the first for this nebula, empirically and theoretically. The C, N, O, and Ne abundances from ORLs are systematically larger than those from CELs. The abundance discrepancies apart from O could be explained by a temperature fluctuation model, and that of O might be by a hydrogen deficient cold component model. We have detected 5 fluorine and several s-process elements. The amounts of [F/H], [Kr/H], and [Xe/H] suggest that BoBn 1 is the most F-rich among F detected PNe and is a heavy s-proces...

  14. The European Southern Observatory and VLT telescopes on Paranal

    Science.gov (United States)

    Boley, P. A.

    2012-01-01

    The Very Large Telescope (VLT) of the European Southern Observatory (ESO) on Cerro Paranal is one of the most influential observing complexes in the world. In this overview lecture, an introduction to the ESO organization and VLT telescopes is presented, along with a small selection of scientific works. Particular attention is given to the importance of the VLT for the Russian scientific community, as well as to present and future perspectives for making use of ESO and VLT data.

  15. Niveles de trombopoyetina en humor acuoso de pacientes con uveítis anterior aguda no infecciosa

    OpenAIRE

    Mondejar Garcia, José Juan

    2015-01-01

    Niveles de trombopoyetina en humor acuoso de pacientes con uveítis anterior aguda no infecciosa Introducción: Las uveítis anteriores agudas no infecciosas (UAANI) son idiopáticas, aunque ligadas a estímulos ambientales y genéticos. Están relacionadas con la respuesta inmune innata y adaptativa. Han sido aisladas citoquinas y factores de crecimiento celular (PEDF y VEGF) en el ojo y el suero de pacientes con uveítis. Los factores de crecimiento (FC) controlan el crecimiento y la diferencia...

  16. The VLT-FLAMES Tarantula survey

    NARCIS (Netherlands)

    Taylor, W.D.; Evans, C.J.; Henault-Brunet, V.; Bastian, N.; Beletsky, Y.; Bestenlehner, J.; Brott, I.; Cantiello, M.; Carraro, G.; Clark, J.S.; Crowther, P.A.; de Koter, A.; de Mink, S.E.; Doran, E.; Dufton, P.L.; Dunstall, P.; Gieles, M.; Grafener, G.; Herrero, A.; Howarth, I.D.; Langer, N.; Lennon, D.J.; Maiz-Apellaniz, J; Markova, N.; Najarro, P.; Puls, J.; Sana, H.A.A.; Simon-Diaz, S.; Smartt, S.J.; Stroud, V.E.; van Loon, J.T.; Vink, J.S.; Walborn, N.R.

    2011-01-01

    The VLT-FLAMES Tarantula Survey is an ESO Large Programme that has provided multi-epoch spectroscopy of over 1000 stars in the 30 Doradus region in the Large Magellanic Cloud. Armed with this unique dataset the assembled consortium is now addressing a broad range of fundamental questions in both ste

  17. When VLT Meets HST : The HUGS Survey

    NARCIS (Netherlands)

    Fontana, A.; Dunlop, J. S.; Paris, D.; Targett, T.; Boutsia, K.; Castellano, M.; Galametz, A.; Grazian, A.; McLure, R.; Merlin, E.; Pentericci, L.; Wuyts, S.; Almaini, O.; Caputi, K.; Chary, R.-R.; Cirasuolo, M.; Conselice, C.; Cooray, A.; Daddi, E.; Dickinson, M.; Faber, S. M.; Fazio, G.; Ferguson, H.; Giallongo, E.; Giavalisco, M.; Grogin, N.; Hathi, N.; Koekemoer, A.; Koo, D. C.; Lucas, R.; Nonino, M.; Rix, H.-W.; Renzini, A.; Rosario, D.; Santini, P.; Scarlata, C.; Sommariva, V.; Stark, D. P.; van der Wel, A.; Vanzella, E.; Wild, V.; Yan, H.; Zibetti, S.

    2014-01-01

    A new ultra-deep near-infrared imaging survey has been completed using the HAWK-I imager at the VLT. It is named HUGS (HAWK-I Ultra Deep Survey and GOODS Survey) and delivers the deepest, highest quality images ever collected in the K-band. HUGS complements the data delivered by the HST CANDELS surv

  18. Deep Impact High Resolution Optical Spectroscopy with the ESO VLT and the Keck 1 telescope

    CERN Document Server

    Jehin, E; Cochran, A L; Hutsemékers, D; Jackson, W M; Manfroid, J; Rauer, H; Schulz, R; Zucconi, J M

    2006-01-01

    We report on observations of comet 9P/Tempel 1 carried out before, during, and after the NASA DEEP IMPACT event (UT July 4), with the optical spectrometers UVES and HIRES mounted on the telescopes Kueyen of the ESO VLT (Chile) and Keck 1 on Mauna Kea (Hawaii), respectively. A total observing time of about 60 hours, distributed over 15 nights around the impact date, allowed us (i) to find a periodic variation of 1.709 +/- 0.009 day in the CN and NH flux, explained by the presence of two major active regions; (ii) to derive a lifetime > ~ 5 x 10^4 s for the parent of the CN radical from a simple modeling of the CN light curve after the impact; (iii) to follow the gas and dust spatial profiles evolution during the 4 hours following the impact and derive the projected velocities (400 m/s and 150 m/s respectively); (iv) to show that the material released by the impact has the same carbon and nitrogen isotopic composition as the surface material (12C/13C = 95 +/- 15 and 14N/15N = 145 +/- 20).

  19. The Great Observatories Origins Deep Survey VLT/FORS2 spectroscopy in the GOODS-South Field

    NARCIS (Netherlands)

    Vanzella, E; Cristiani, S; Dickinson, M; Kuntschner, H; Moustakas, LA; Nonino, M; Rosati, P; Stern, D; Cesarsky, C; Ettori, S; Ferguson, HC; Fosbury, RAE; Giavalisco, M; Haase, J; Renzini, A; Rettura, A; Serra, P

    2005-01-01

    We present the first results of the ESO/ GOODS program of spectroscopy of faint galaxies in the Chandra Deep Field South ( CDF- S). 399 spectra of 303 unique targets have been obtained in service mode with the FORS2 spectrograph at the ESO/ VLT, providing 234 redshift determinations ( the median of

  20. Enfermedades articulares y uveítis Articular diseases and uveitis

    Directory of Open Access Journals (Sweden)

    J.M. Benítez del Castillo

    2008-01-01

    Full Text Available La inflamación ocular es una manifestación clínica frecuente de múltiples enfermedades sistémicas autoinmunes, siendo de gran relevancia en las espondiloartropatías. Dentro del grupo de las espondiloartropatías existen diferentes entidades clínicas, asociándose a diferentes patrones de uveítis. Se han definido una serie de patrones discriminativos que relacionan formas concretas de uveítis con determinadas enfermedades sistémicas u oculares. La uveítis anterior aguda unilateral recidivante es la más frecuente en las espondiloartropatías, y puede ser la forma de inicio de una espondiloartropatía no diagnosticada previamente. La colaboración entre oftalmólogos y reumatólogos o internistas es fundamental para el correcto manejo y tratamiento de estos pacientes.Ocular inflammation is a common clinical manifestation related to several autoimmune systemic disorders, specially spondyloarthropaties. In this group, there are different clinical diseases that are related to special uveitic patterns. Several discriminative patterns have been defined that closely link uveitis with certain systemic or ophthalmic diseases. Unilateral recurrent anterior acute uveitis is the most frequent form of uveitis related to spondyloarthropaties, and is sometimes the initial manifestation of an undiagnosed spondyloarthropaty. The collaboration of ophthalmologists, rheumatologists and internal medicine specialists is very important for the correct management and treatment of these patients.

  1. Progress on the VLT Adaptive Optics Facility

    Science.gov (United States)

    Arsenault, R.; Madec, P.-Y.; Paufique, J.; Ströbele, S.; Pirard, J.-F.; Vernet, É.; Hackenberg, W.; Hubin, N.; Jochum, L.; Kuntschner, H.; Glindemann, A.; Amico, P.; Lelouarn, M.; Kolb, J.; Tordo, S.; Donaldson, R.; Sã¶Nke, C.; Bonaccini Calia, D.; Conzelmann, R.; Delabre, B.; Kiekebusch, M.; Duhoux, P.; Guidolin, I.; Quattri, M.; Guzman, R.; Buzzoni, B.; Comin, M.; Dupuy, C.; Quentin, J.; Lizon, J.-L.; Silber, A.; Jolly, P.; Manescau, A.; Hammersley, P.; Reyes, J.; Jost, A.; Duchateau, M.; Heinz, V.; Bechet, C.; Stuik, R.

    2010-12-01

    The Very Large Telescope (VLT) Adaptive Optics Facility is a project that will transform one of the VLT's Unit Telescopes into an adaptive telescope that includes a deformable mirror in its optical train. For this purpose the secondary mirror is to be replaced by a thin shell deformable mirror; it will be possible to launch four laser guide stars from the centrepiece and two adaptive optics modules are being developed to feed the instruments HAWK-I and MUSE. These modules implement innovative correction modes for seeing improvement through ground layer adaptive optics and, for high Strehl ratio performance, laser tomography adaptive correction. The performance of these modes will be tested in Europe with a custom test bench called ASSIST. The project has completed its final design phase and concluded an intense phase of procurement; the year 2011 will see the beginning of assembly, integration and tests.

  2. ESO VLT laser guide star facility

    Science.gov (United States)

    Bonaccini, Domenico; Hackenberg, Wolfgang K.; Cullum, Martin J.; Brunetto, Enzo; Ott, Thomas; Quattri, Marco; Allaert, Eric; Dimmler, Martin; Tarenghi, Massimo; Van Kersteren, A.; Di Chirico, C.; Buzzoni, Bernard; Gray, Peter; Tamai, R.; Tapia, M.

    2002-02-01

    We report in this paper on the design and progress of the ESO Laser Guide Star Facility. The project will create a user facility embedded in UT4, to produce in the Earth's Mesosphere Laser Guide Stars, which extend the sky coverage of Adaptive Optics systems on the VLT UT4 telescope. Embedded into the project are provisions for multiple LGS to cope with second generation MCAO instruments.

  3. Uveítis sifilítica asociada al virus de inmunodeficiencia humana

    Directory of Open Access Journals (Sweden)

    Isabel Ambou Frutos

    Full Text Available La sífilis es una infección crónica y multisistémica, producida por la espiroqueta Treponema pallidum. Las manifestaciones oculares de la sífilis son varias y pueden afectar todas las estructuras oculares. La uveítis es el tipo de afectación ocular más frecuente. Puede presentarse en la fase secundaria, latente o terciaria y cursa de forma bilateral en el 50 % de los casos. También puede verse asociada al virus de inmunodeficiencia humana. Desde la introducción de la terapia antirretroviral de gran actividad, la mortalidad asociada al SIDA disminuyó y la incidencia de sífilis y otras enfermedades de trasmisión sexual aumentó como consecuencia de la expansión de la población homosexual. Teniendo en cuenta la gran variedad de formas de presentación, se le conoce como la gran simuladora y forma parte del diagnóstico diferencial de cualquier uveítis. Presentamos el caso de un paciente masculino de 64 años de edad que acude al Cuerpo de Guardia, donde refiere visión borrosa del ojo derecho de aproximadamente 45 días de evolución, asociado a enrojecimiento ocular, dolor y molestias a la luz, a quien posteriormente se le diagnóstico una uveítis sifilítica asociada al virus de inmunodeficincia humana.

  4. Uveíte na artrite idiopática juvenil Uveitis in juvenile idiopathic arthritis

    Directory of Open Access Journals (Sweden)

    Adriana M. Roberto

    2002-02-01

    Full Text Available Objetivo: avaliar a freqüência de uveíte anterior crônica em pacientes com artrite idiopática juvenil (AIJ e sua associação com a presença do fator antinúcleo (FAN. Casuística e métodos: foram avaliadas, retrospectivamente, 72 crianças com diagnóstico confirmado de AIJ, que tiveram avaliação oftalmológica através da biomicroscopia para exame da câmara anterior da úvea, determinação do FAN (imunofluorescência indireta e fator reumatóide (FR (prova do látex no período inicial da doença. Para os pacientes com FAN positivo, esta avaliação foi realizada a cada três meses, e, caso contrário, a cada seis meses.Resultados: dos 72 pacientes com AIJ, 40 (55,5% crianças eram do sexo masculino e 36 (50% caucasóides. A idade média de início da AIJ foi 6,4 anos (1 a 14 anos, e a idade média na época do estudo foi de 10,4 anos (1 a 19 anos. De acordo com o tipo de início da AIJ, em 32 (44,4% crianças era pauciarticular (17 meninos e 15 meninas, em 30 (41,6% era poliarticular (17 meninos e 13 meninas, e em 10 (14% era sistêmico (6 meninos e 4 meninas. A presença de uveíte anterior crônica foi detectada em cinco (6,5% crianças com idade média de 11,4 anos. Destas, quatro (80% eram do tipo de início pauciarticular (três meninas do tipo I, com FAN positivo, e um menino do tipo I, FAN negativo, e uma menina com doença poliarticular (FAN e FR negativos. Neste grupo, a idade de início da AIJ foi em média 5,1 anos (3 a 12 anos, e a idade de início da uveíte foi em média de 9 anos (4 a 16 anos. O FAN foi positivo em 3/5 pacientes (60% com uveíte. Dentre os pacientes com AIJ e sem uveíte (67 crianças, oito (12% apresentaram FAN positivo. Quanto à evolução dos pacientes com comprometimento ocular, três crianças tiveram apenas um episódio de uveíte, e duas crianças apresentaram quatro recorrências da uveíte com catarata sem atividade articular associada. A presença do FAN foi estatisticamente mais freq

  5. VLT/SINFONI spectroscopy of the superantennae

    Directory of Open Access Journals (Sweden)

    J. Reunanen

    2007-01-01

    Full Text Available Presentamos los resultados de espectroscopia de campo integral en bandas H y K VLT/SINFONI de IRAS 19254-7245 (Superantennae, una ULRIG cercana con un AGN embebido. Los mapas de las líneas, campos de velocidades y mapas de dispersión de velocidades se presentan para varias líneas de emisión. Las proporciones de las líneas de emisión de H2 son consistentes con la excitación térmica, debida probablemente a choques.

  6. Data Flow System for the VLT Interferometer

    Science.gov (United States)

    Ballester, P.; Licha, T.; Percheron, I.; Sabet, C.

    2006-07-01

    A milestone on the accuracy of angular measurements is reached with each new instrument on the VLT interferometer: about 10 milliarcsec for MIDI (N Band), 1 milliarcsec for AMBER (JHK bands) and, later, the ultimate goal of 10 microarcsec for the PRIMA imaging and astrometry facility. Extracting the science information from these measurements requires a unified understanding of the data obtained by modelling, homogeneous calibration of large datasets and robust data reduction methods. We describe in this poster the operational tools provided for observation preparation, pipeline processing, and data quality control.

  7. Beam combination modes of the VLT

    Science.gov (United States)

    Merkle, Fritz

    The optical configuration of the ESO Very Large Telescope (VLT) is based on a linear array of 4 independently mounted 8-m telescopes. This concept allows a flexible and versatile use of the telescopes. They can be operated either independently or in various combination schemes. In the latter case, the light collected with the unit telescopes is fed via beam combination optics to the combined focus. The incoherent combination with a combined coude focus offers the light collecting power approximately equivalent to a 16-m single dish telescope. The efficiency of the combined foci operation is only given if the losses in the combining train are minimized.

  8. With the VLT Interferometer towards Sharper Vision

    Science.gov (United States)

    2000-05-01

    The Nova-ESO VLTI Expertise Centre Opens in Leiden (The Netherlands) European science and technology will gain further strength when the new, front-line Nova-ESO VLTI Expertise Centre (NEVEC) opens in Leiden (The Netherlands) this week. It is a joint venture of the Netherlands Research School for Astronomy (NOVA) (itself a collaboration between the Universities of Amsterdam, Groningen, Leiden, and Utrecht) and the European Southern Observatory (ESO). It is concerned with the Very Large Telescope Interferometer (VLTI). The Inauguration of the new Centre will take place on Friday, May 26, 2000, at the Gorlaeus Laboratory (Lecture Hall no. 1), Einsteinweg 55 2333 CC Leiden; the programme is available on the web. Media representatives who would like to participate in this event and who want further details should contact the Nova Information Centre (e-mail: jacques@astro.uva.nl; Tel: +31-20-5257480 or +31-6-246 525 46). The inaugural ceremony is preceded by a scientific workshop on ground and space-based optical interferometry. NEVEC: A Technology Centre of Excellence As a joint project of NOVA and ESO, NEVEC will develop in the coming years the expertise to exploit the unique interferometric possibilities of the Very Large Telescope (VLT) - now being built on Paranal mountain in Chile. Its primary goals are the * development of instrument modeling, data reduction and calibration techniques for the VLTI; * accumulation of expertise relevant for second-generation VLTI instruments; and * education in the use of the VLTI and related matters. NEVEC will develop optical equipment, simulations and software to enable interferometry with VLT [1]. The new Center provides a strong impulse to Dutch participation in the VLTI. With direct involvement in this R&D work, the scientists at NOVA will be in the front row to do observations with this unique research facility, bound to produce top-level research and many exciting new discoveries. The ESO VLTI at Paranal ESO PR Photo 14a/00

  9. Obsolescence of electronics at the VLT

    Science.gov (United States)

    Hüdepohl, Gerhard; Haddad, Juan-Pablo; Lucuix, Christian

    2016-07-01

    The ESO Very Large Telescope Observatory (VLT) at Cerro Paranal in Chile had its first light in 1998. Most of the telescopes' electronics components were chosen and designed in the mid 1990s and are now around 20 years old. As a consequence we are confronted with increasing failure rates due to aging and lack of spare parts, since many of the components are no longer available on the market. The lifetime of large telescopes is generally much beyond 25 years. Therefore the obsolescence of electronics components and modules becomes an issue sooner or later and forces the operations teams to upgrade the systems to new technology in order to avoid that the telescope becomes inoperable. Technology upgrade is a time and money consuming process, which in many cases is not straightforward and has various types of complications. This paper shows the strategy, analysis, approach, timeline, complications and progress in obsolescence driven electronics upgrades at the ESO Very Large Telescope (VLT) at the Paranal Observatory.

  10. Enhancing [Spatial] Creativity – Enhancing creativity of architects by applying unconventional virtual environments (UVEs

    Directory of Open Access Journals (Sweden)

    Alireza Mahdizadeh Hakak

    2017-07-01

    Full Text Available Potentials of virtual environment for enhancing creativity of architects have shaped this research. There is no singular definition of creativity. In fact, there are more than 100 different definitions for creativity according to different contexts and disciplines. Nevertheless, it is possible to confine the boundaries of definitions and address creativity within a confined framework. The first practical step was thus to perform an in-depth literature survey to define a boundary condition for the widespread topic of “creativity” and identify vital research questions pertaining to creativity. In this regard, personality and behavior of creative people; mood, state, temper, intelligence vs. creativity, motivation and so forth were ignored. Instead, cognitive aspects of creativity such as thinking patterns, conceptual blending, idea expansion and tolerance of ambiguity have been focused upon.The second step was to test whether starting a design procedure with a 2 or a 3-dimensional mode of thinking has any correlation with creativity. An experiment pertaining to this test was designed in which participants were asked to perform the same design task once with 2D tools and environments (e.g. traditional pen and paper and the next time by applying 3D tools and environments (e.g. 3D software. A jury of experts in the field of design subjectively compared the results and arrived at a conclusion that participates generated more creative ideas by implementing 3D environments/tools. The third step, involved the introduction of unconventional virtual environments (UVEs, which subsequently lead to the creation of a hypothesis. This hypothesis tries to connect navigation in UVEs with the enhancement of creativity.  Characteristics of UVEs and theoretical arguments around the hypothesis were also discussed. The fourth step, involved a discussion on two effective parameters of creativity: 1- Tolerance of ambiguity2- Conceptual blendingAttempts to

  11. O papel das quimiocinas nas uveítes The role of chemokines in uveitis

    Directory of Open Access Journals (Sweden)

    Roberto Martins Gonçalves

    2007-03-01

    Full Text Available A inflamação é parte do processo fisiológico que visa reparar o dano tecidual causado por infecção, trauma, auto-imunidade. Quando este processo fisiológico encontra-se alterado, pode contribuir para o aumento do dano tecidual. As quimiocinas e seus receptores são importantes elementos envolvidos no processo de migração celular para os tecidos inflamados. Nas doenças oculares, principalmente nas uveítes, estas proteínas estão sendo identificadas como importantes mediadores da resposta inflamatória. Esta revisão visa discutir o papel das quimiocinas em diversas doenças oculares, dando ênfase aos processos uveíticos.Inflammation is part of the physiological process that aims at repairing the damage produced by different causes such as infection, trauma, and autoimmune disease. However, when this physiological process is not regulated, it can contribute to the increase in tissue damage. Chemokines and their receptors are major factors involved in the process of cell migration into inflamed tissues. In the ocular diseases, mainly in uveitis, such proteins have been identified as important mediators of the inflammation process. This review discusses the role of chemokines in several ocular diseases, with emphasis on the uveitic process.

  12. VLT Unit Telescopes Named at Paranal Inauguration

    Science.gov (United States)

    1999-03-01

    This has been a busy, but also a very successful and rewarding week for the European Southern Observatory and its staff. While "First Light" was achieved at the second 8.2-m VLT Unit Telescope (UT2) ahead of schedule, UT1 produced its sharpest image so far. This happened at a moment of exceptional observing conditions in the night between March 4 and 5, 1999. During a 6-min exposure of the majestic spiral galaxy, NGC 2997 , stellar images of only 0.25 arcsec FWHM (full-width half-maximum) were recorded. This and two other frames of nearly the same quality have provided the base for the beautiful colour-composite shown above. At this excellent angular resolution, individual star forming regions are well visible along the spiral arms. Of particular interest is the peculiar, twisted shape of the long spiral arm to the right. The Paranal Inauguration The official inauguration of the Paranal Observatory took place in the afternoon of March 5, 1999, in the presence of His Excellency, the President of the Republic of Chile, Don Eduardo Frei Ruiz-Tagle, and ministers of his cabinet, as well the Ambassadors to Chile of the ESO member states and many other distinguished guests. The President of the ESO Council, Mr. Henrik Grage, and the ESO Director General, Professor Riccardo Giacconi, were the foremost representatives of the ESO organisation; most members of the ESO Council and ESO staff also participated. A substantial number of media representatives from Europe and Chile were present and reported - often live - from Paranal during the afternoon and evening. The guests were shown the impressive installations at the new observatory, including the first and second 8.2-m VLT Unit Telescopes; the latter having achieved "First Light" just four days before. A festive ceremony took place in the dome of UT2, under the large telescope structure that had been tilted towards the horizon to make place for the numerous participants. After an introductory address by the ESO Director

  13. Incidência e etiologia de uveítes em Curitiba Incidence and etiology of uveitis in Curitiba

    Directory of Open Access Journals (Sweden)

    Marcelo Luis Gehlen

    1999-10-01

    Full Text Available Objetivo: Determinar a incidência e a etiologia dos casos de uveítes em Curitiba-PR. Métodos: Foram estudados 68 casos de uveítes em Curitiba, PR, atendidos no ambulatório de oftalmologia no período de janeiro a abril de 1998 procurando estabelecer o diagnóstico a partir de ampla investigação clínica e laboratorial. Resultados: Em nosso estudo, constatamos que a uveíte posterior foi a mais encontrada (49%, seguindo-se a panuveíte (29% e, com menor freqüência, a uveíte anterior (22%. A etiologia mais freqüente para as uveítes posteriores foi a toxoplasmose, responsável por 88% dos casos. Entre as panuveítes, novamente a toxoplasmose prevaleceu, com 85% e, dentro das uveítes anteriores, a principal causa foi a espondilite anquilosante com 20%. Conclusão: Em Curitiba, há um predomínio de uveítes posteriores e panuveítes, sendo a causa mais comum a toxoplasmose. No entanto, enfatiza-se que existem outras causas importantes de uveítes que devem ser lembradas pelo oftalmologista na investigação clínica.Purpose: To study the incidence and etiology of uveitis in Curitiba, PR, Brazil. Methods: Sixty-eight cases of uveitis were studied in Curitiba, PR between January and April, 1998. Clinical and laboratorial research was performed in order to establish the diagnosis. Results: In this study, we found that posterior uveitis was the most frequent (49%, followed by panuveitis (29%, and, less frequently, anterior uveitis (22%. The major etiology of posterior uveitis was toxoplasmosis, responsible for 88% of the cases; among panuveitis, toxoplasmosis also predomi-nated, representing 85% and, the main cause of anterior uveitis was ankylosing spondilytis with 20%. Conclusions: In Curitiba, posterior uveitis and panuveitis predominate, and the most frequent etiology is toxoplas-mosis. However, its important to emphasize that there are other important causes of uveitis which should be remem-bered by the ophthalmologist during the

  14. Espondilite anquilosante e uveíte: revisão Ankylosing spondylitis and uveitis: overview

    Directory of Open Access Journals (Sweden)

    Enéias Bezerra Gouveia

    2012-10-01

    Full Text Available O presente trabalho propõe uma revisão de epidemiologia, patogênese, quadro clínico, diagnóstico e tratamento da espondilite anquilosante e sua associação com alteração ocular com a devida condução da doença e suas manifestações. Os autores utilizaram em sua pesquisa os bancos de dados PubMed (MEDLINE, LILACS e Biblioteca do Centro de Estudos de Oftalmologia. A espondilite anquilosante é uma doença inflamatória crônica que acomete preferencialmente o esqueleto axial, podendo evoluir com rigidez e limitação funcional progressiva. Seu início costuma ocorrer por volta da segunda à terceira década de vida, preferencialmente em indivíduos do gênero masculino, caucasianos e HLA-B27-positivos. Sua etiologia e patogênese não são completamente elucidadas, e seu diagnóstico costuma ser tardio. O controle clínico e o tratamento são frequentemente satisfatórios.A uveíte anterior aguda é a manifestação extra-articular mais comum, ocorrendo em cerca de 20%-30% dos pacientes com espondilite anquilosante. Aproximadamente metade dos casos de uveíte anterior aguda está associada à presença do antígeno HLA-B27, podendo ser a primeira manifestação de uma doença reumatológica não diagnosticada, geralmente com boa resposta terapêutica e bom prognóstico. Concluímos que, para melhor avaliação e tratamento dos pacientes com uveíte, é importante maior integração entre oftalmologistas e reumatologistas.The present article reviews the epidemiology, pathogenesis, clinical features, diagnosis, and treatment of ankylosing spondylitis and its association with ocular changes. The authors used the PubMed (MEDLINE, LILACS, and Ophthalmology Library databases. Ankylosing spondylitis is a chronic inflammatory disease that usually affects the axial skeleton and can progress to stiffness and progressive functional limitation. Ankylosing spondylitis usually begins around the second to third decade of life, preferentially in HLA

  15. VLT FORS2 comparative transmission spectral survey of clear and cloudy exoplanet atmospheres

    Science.gov (United States)

    Nikolov, Nikolay; Sing, David; Gibson, Neale; Evans, Thomas; Barstow, Joanna Katy; Kataria, Tiffany; Wilson, Paul A.

    2016-10-01

    Transmission spectroscopy is a key to unlocking the secrets of close-in exoplanet atmospheres. Observations have started to unveil a vast diversity of irradiated giant planet atmospheres with clouds and hazes playing a definitive role across the entire mass and temperature regime. We have initiated a ground-based, multi-object transmission spectroscopy of a hand full of hot Jupiters, covering the wavelength range 360-850nm using the recently upgraded FOcal Reducer and Spectrograph (FORS2) mounted on the Very Large Telescope (VLT) at the European Southern Observatory (ESO). These targets were selected for comparative follow-up as their transmission spectra showed evidence for alkali metal absorption, based on the results of Hubble Space Telescope (HST) observations. This talk will discuss the first results from the programme, demonstrating excellent agreement between the transmission spectra measured from VLT and HST and further reinforce the findings of clear, cloudy and hazy atmospheres. More details will be discussed on the narrow alkali features obtained with FORS2 at higher resolution, revealing its high potential in securing optical transmission spectra. These FORS2 observations are the first ground-based detections of clear, cloudy and hazy hot-Jupiter atmosphere with a simultaneous detections of Na, K, and H2 Rayleigh scattering. Our program demonstrates the large potential of the instrument for optical transmission spectroscopy, capable of obtaining HST-quality light curves from the ground. Compared to HST, the larger aperture of VLT will allow for fainter targets to be observed and higher spectral resolution, which can greatly aid comparative exoplanet studies. This is important for further exploring the diversity of exoplanet atmospheres and is particularly complementary to the near- and mid-IR regime, to be covered by the upcoming James-Webb Space Telescope (JWST) and is readily applicable to less massive planets down to super-Earths.

  16. VLT imaging of the {\\beta} Pictoris gas disk

    CERN Document Server

    Nilsson, R; Olofsson, G; Fathi, K; Thébault, Ph; Liseau, R

    2012-01-01

    Circumstellar debris disks older than a few Myr should be largely devoid of primordial gas remaining from the protoplanetary disk phase. Tracing the origin of observed atomic gas in Keplerian rotation in the edge-on debris disk surrounding the ~12 Myr old star {\\beta} Pictoris requires more detailed information about its spatial distribution than has previously been acquired by limited slit spectroscopy. Especially indications of asymmetries and presence of Ca II gas at high disk latitudes call for additional investigation. We set out to recover a complete image of the Fe I and Ca II gas emission around {\\beta} Pic by spatially resolved, high-resolution spectroscopic observations to better understand the morphology and origin of the gaseous disk component. The multiple fiber facility FLAMES/GIRAFFE at the VLT, with the large IFU ARGUS, was used to obtain spatially resolved optical spectra in four regions covering the northeast and southwest side of the disk. Emission lines from Fe I and Ca II were mapped and ...

  17. VLT FORS2 comparative transmission spectral survey of clear and cloudy exoplanet atmospheres

    Science.gov (United States)

    Nikolov, Nikolay; Sing, David K.; Gibson, Neale; Fortney, Jonathan J.; Evans, Tom M.; Barstow, Joanna; Kataria, Tiffany; Wilson, Paul

    2017-01-01

    Thousands of transiting exoplanets are known today but not many have been studied in transmission. While observations with the Hubble Space Telescope (HST) have started to reveal a diversity of atmosphere types, drawing robust conclusions about the underlying population is hampered by the small sample size. This can be greatly aided by ground-based telescopes, equipped with multi-object spectrographs by their unprecedented access to the abundance of fainter systems that HST cannot observe. We have initiated a ground-based, multi-object transmission spectroscopy of a handful of hot gas-giants, covering the wavelength range 360-850nm, using the recently upgraded FOcal Reducer and Spectrograph (FORS2) mounted on the Very Large Telescope (VLT). These exoplanets were selected for a comparative follow-up as their transmission spectra showed evidence for alkali metal absorption, based on the results of HST observations. Here we will discuss first results from the program, demonstrating an excellent agreement between the transmission spectra measured from VLT and HST and detections of Na and K absorption and scattering by clouds/hazes in the atmospheres of several exoplanets. More details will be discussed on the narrow alkali features obtained with FORS2 at higher resolution, revealing its high potential in obtaining optical transmission spectra, which can greatly aid comparative exoplanet studies.

  18. VLT observations of the asymmetric Etched Hourglass Nebula, MyCn 18

    CERN Document Server

    Clyne, N; Lloyd, M; Matsuura, M; Singh, N; Meaburn, J

    2014-01-01

    Context. The mechanisms that form extreme bipolar planetary nebulae remain unclear. Aims. The physical properties, structure, and dynamics of the bipolar planetary nebula, MyCn 18, are investigated in detail with the aim of understanding the shaping mechanism and evolutionary history of this object. Methods. VLT infrared images, VLT ISAAC infrared spectra, and long-slit optical Echelle spectra are used to investigate MyCn 18. Morpho-kinematic modelling was used to firmly constrain the structure and kinematics of the source. A timescale analysis was used to determine the kinematical age of the nebula and its main components. Results. A spectroscopic study of MyCn 18's central and offset region reveals the detailed make-up of its nebular composition. Molecular hydrogen, atomic helium, and Bracket gamma emission are detected from the central regions of MyCn 18. ISAAC spectra from a slit position along the narrow waist of the nebula demonstrate that the ionised gas resides closer to the centre of the nebula than ...

  19. SCIENCE OPPORTUNITIES ON THE VLT INTERFEROMETER

    Directory of Open Access Journals (Sweden)

    M. Schöller

    2010-01-01

    Full Text Available El interferómetro del VLT está desde hace varios años en operaciones científicas, con nuevas oportunidades disponibles cada vez que nuevas instalaciones están siendo integradas. La mayor parte de estos pasos son fácilmente visibles, pero algunas posibilidades se presentan a partir de mejoras simples. Detallo el potencial científico del VLTI, dando una descripción de la infraestructura y los modos ofrecidos por los instrumentos. Luego examino las limitaciones fijadas por la accesibilidad del cielo, flujo del objeto en el espectro visible e infrarrojo, o la morfología del objeto, seguida por una discusión de qué información se puede extraer de las mediciones del VLTI. Finalizo con una perspectiva en las mejoras futuras del VLTI.

  20. "First Light" for the VLT Interferometer

    Science.gov (United States)

    2001-03-01

    Excellent Fringes From Bright Stars Prove VLTI Concept Summary Following the "First Light" for the fourth of the 8.2-m telescopes of the VLT Observatory on Paranal in September 2000, ESO scientists and engineers have just successfully accomplished the next major step of this large project. On March 17, 2001, "First Fringes" were obtained with the VLT Interferometer (VLTI) - this important event corresponds to the "First Light" for an astronomical telescope. At the VLTI, it occurred when the infrared light from the bright star Sirius was captured by two small telescopes and the two beams were successfully combined in the subterranean Interferometric Laboratory to form the typical pattern of dark and bright lines known as " interferometric fringes ". This proves the success of the robust VLTI concept, in particular of the "Delay Line". On the next night, the VLTI was used to perform a scientific measurement of the angular diameter of another comparatively bright star, Alpha Hydrae ( Alphard ); it was found to be 0.00929±0.00017 arcsec . This corresponds to the angular distance between the two headlights of a car as seen from a distance of approx. 35,000 kilometres. The excellent result was obtained during a series of observations, each lasting 2 minutes, and fully confirming the impressive predicted abilities of the VLTI . This first observation with the VLTI is a monumental technological achievement, especially in terms of accuracy and stability . It crucially depends on the proper combination and functioning of a large number of individual opto-mechnical and electronic elements. This includes the test telescopes that capture the starlight, continuous and extremely precise adjustment of the various mirrors that deflect the light beams as well as the automatic positioning and motion of the Delay Line carriages and, not least, the optimal tuning of the VLT INterferometer Commissionning Instrument (VINCI). These initial observations prove the overall concept for the

  1. VLT Smashes the Record of the Farthest Known Galaxy

    Science.gov (United States)

    2004-03-01

    Redshift 10 Galaxy discovered at the Edge of the Dark Ages [1] Summary Using the ISAAC near-infrared instrument on ESO's Very Large Telescope, and the magnification effect of a gravitational lens, a team of French and Swiss astronomers [2] has found several faint galaxies believed to be the most remote known. Further spectroscopic studies of one of these candidates has provided a strong case for what is now the new record holder - and by far - of the most distant galaxy known in the Universe. Named Abell 1835 IR1916, the newly discovered galaxy has a redshift of 10 [3] and is located about 13,230 million light-years away. It is therefore seen at a time when the Universe was merely 470 million years young, that is, barely 3 percent of its current age. This primeval galaxy appears to be ten thousand times less massive than our Galaxy, the Milky Way. It might well be among the first class of objects which put an end to the Dark Ages of the Universe. This remarkable discovery illustrates the potential of large ground-based telescopes in the near-infrared domain for the exploration of the very early Universe. PR Photo 05a/04: Abell 1835 IR1916 - the Farthest Galaxy - Seen in the Near-Infrared PR Photo 05b/04: Two-dimensional Spectra of Abell 1835 IR1916 Digging into the past Like palaeontologists who dig deeper and deeper to find the oldest remains, astronomers try to look further and further to scrutinise the very young Universe. The ultimate quest? Finding the first stars and galaxies that formed just after the Big Bang. More precisely, astronomers are trying to explore the last "unknown territories", the boundary between the "Dark Ages" and the "Cosmic Renaissance". Rather shortly after the Big Bang, which is now believed to have taken place some 13,700 million years ago, the Universe plunged into darkness. The relic radiation from the primordial fireball had been stretched by the cosmic expansion towards longer wavelengths and neither stars nor quasars had yet been

  2. Next VLT Instrument Ready for the Astronomers

    Science.gov (United States)

    2000-02-01

    FORS2 Commissioning Period Successfully Terminated The commissioning of the FORS2 multi-mode astronomical instrument at KUEYEN , the second FOcal Reducer/low dispersion Spectrograph at the ESO Very Large Telescope, was successfully finished today. This important work - that may be likened with the test driving of a new car model - took place during two periods, from October 22 to November 21, 1999, and January 22 to February 8, 2000. The overall goal was to thoroughly test the functioning of the new instrument, its conformity to specifications and to optimize its operation at the telescope. FORS2 is now ready to be handed over to the astronomers on April 1, 2000. Observing time for a six-month period until October 1 has already been allocated to a large number of research programmes. Two of the images that were obtained with FORS2 during the commissioning period are shown here. An early report about this instrument is available as ESO PR 17/99. The many modes of FORS2 The FORS Commissioning Team carried out a comprehensive test programme for all observing modes. These tests were done with "observation blocks (OBs)" that describe the set-up of the instrument and telescope for each exposure in all details, e.g., position in the sky of the object to be observed, filters, exposure time, etc.. Whenever an OB is "activated" from the control console, the corresponding observation is automatically performed. Additional information about the VLT Data Flow System is available in ESO PR 10/99. The FORS2 observing modes include direct imaging, long-slit and multi-object spectroscopy, exactly as in its twin, FORS1 at ANTU . In addition, FORS2 contains the "Mask Exchange Unit" , a motorized magazine that holds 10 masks made of thin metal plates into which the slits are cut by means of a laser. The advantage of this particular observing method is that more spectra (of more objects) can be taken with a single exposure (up to approximately 80) and that the shape of the slits can be

  3. The design of ERIS for the VLT

    Science.gov (United States)

    Amico, P.; Marchetti, E.; Pedichini, F.; Baruffolo, A.; Delabre, B.; Duchateau, M.; Ekinci, M.; Fantinel, D.; Fedrigo, E.; Finger, G.; Frank, C.; Hofmann, R.; Jolley, P.; Lizon, J. L.; Le Louarn, M.; Madec, P.-Y.; Soenke, C.; Weisz, H.

    2012-09-01

    The Enhanced Resolution Imager and Spectrograph (ERIS) is the next-generation instrument planned for the Very Large Telescope (VLT) and the Adaptive Optics Facility (AOF)1. It is an AO assisted instrument that will make use of the Deformable Secondary Mirror and the new Laser Guide Star Facility (4LGSF), and it is designed for the Cassegrain focus of the telescope UT4. The project just concluded its conceptual design phase and is awaiting formal approval to continue to the next phase. ERIS will offer 1-5 μm imaging and 1-2.5 μm integral field spectroscopic capabilities with high Strehl performance. As such it will replace, with much improved single conjugated AO correction, the most scientifically important and popular observing capabilities currently offered by NACO2 (diffraction limited imaging in JM band, Sparse Aperture Masking and APP coronagraphy) and by SINFONI3, whose instrumental module, SPIFFI, will be re-used in ERIS. The Cassegrain location and the performance requirements impose challenging demands on the project, from opto-mechanical design to cryogenics to the operational concept. In this paper we describe the baseline design proposed for ERIS and discuss these technical challenges, with particular emphasis on the trade-offs and the novel solutions proposed for building ERIS.

  4. VLT Captures First Direct Spectrum of an Exoplanet

    Science.gov (United States)

    2010-01-01

    eclipse", and then the spectrum could be extracted by comparing the light of the star before and after. However, this method can only be applied if the orientation of the exoplanet's orbit is exactly right, which is true for only a small fraction of all exoplanetary systems. The present spectrum, on the other hand, was obtained from the ground, using ESO's Very Large Telescope (VLT), in direct observations that do not depend on the orbit's orientation. As the host star is several thousand times brighter than the planet, this is a remarkable achievement. "It's like trying to see what a candle is made of, by observing it from a distance of two kilometres when it's next to a blindingly bright 300 Watt lamp," says Janson. The discovery was made possible by the infrared instrument NACO, mounted on the VLT, and relied heavily on the extraordinary capabilities of the instrument's adaptive optics system [3]. Even more precise images and spectra of giant exoplanets are expected both from the next generation instrument SPHERE, to be installed on the VLT in 2011, and from the European Extremely Large Telescope. The newly collected data show that the atmosphere enclosing the planet is still poorly understood. "The features observed in the spectrum are not compatible with current theoretical models," explains co-author Wolfgang Brandner. "We need to take into account a more detailed description of the atmospheric dust clouds, or accept that the atmosphere has a different chemical composition from that previously assumed." The astronomers hope to soon get their hands on the fingerprints of the other two giant planets so they can compare, for the first time, the spectra of three planets belonging to the same system. "This will surely shed new light on the processes that lead to the formation of planetary systems like our own," concludes Janson. Notes [1] As every rainbow demonstrates, white light can be split up into different colours. Astronomers artificially split up the light they

  5. The Earth as an extrasolar transiting planet - II: HARPS and UVES detection of water vapour and biogenic species O$_2$ and O$_3$

    CERN Document Server

    Arnold, Luc; Vidal-Madjar, Alfred; Dumusque, Xavier; Nitschelm, Christian; Querel, Richard R; Hedelt, Pascal; Berthier, Jérôme; Lovis, Christophe; Moutou, Claire; Ferlet, Roger; Crooker, David

    2014-01-01

    The atmospheric composition of transiting exoplanets can be characterized during transit by spectroscopy. For an Earth twin, models predict that oxygen and ozone biogenic gases should be detectable, as well as water vapour, a molecule linked to habitability as we know it on Earth. The aim is to measure the Earth radius versus wavelength at the highest spectral resolution available to fully characterize the signature of the Earth seen as a transiting exoplanet. We present observations of Dec. 21, 2010 Moon eclipse. The Earth observed from the Moon during a lunar eclipse transits in front of the Sun and opens access to the Earth atmosphere transmission spectrum. We used two different ESO spectrographs to take penumbra and umbra high-resolution spectra from 3100 to 10400\\AA. A change in moisture above the telescope compromised the UVES data. We explain how we correct this effect. The data are analyzed by three different methods, the first method being the method described in Vidal-Madjar et al. 2010 based on the...

  6. An extensive VLT/X-shooter library of photospheric templates of pre-main sequence stars

    Science.gov (United States)

    Manara, C. F.; Frasca, A.; Alcalá, J. M.; Natta, A.; Stelzer, B.; Testi, L.

    2017-09-01

    Context. Studies of the formation and evolution of young stars and their disks rely on knowledge of the stellar parameters of the young stars. The derivation of these parameters is commonly based on comparison with photospheric template spectra. Furthermore, chromospheric emission in young active stars impacts the measurement of mass accretion rates, a key quantity for studying disk evolution. Aims: Here we derive stellar properties of low-mass (M⋆≲ 2 M⊙) pre-main sequence stars without disks, which represent ideal photospheric templates for studies of young stars. We also use these spectra to constrain the impact of chromospheric emission on the measurements of mass accretion rates. The spectra are reduced, flux-calibrated, and corrected for telluric absorption, and are made available to the community. Methods: We derive the spectral type for our targets by analyzing the photospheric molecular features present in their VLT/X-shooter spectra by means of spectral indices and comparison of the relative strength of photospheric absorption features. We also measure effective temperature, gravity, projected rotational velocity, and radial velocity from our spectra by fitting them with synthetic spectra with the ROTFIT tool. The targets have negligible extinction (AVhttp://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/605/A86

  7. Uveítes anteriores associadas a doenças sistêmicas Anterior uveitis associated to systemic diseases

    Directory of Open Access Journals (Sweden)

    Maria Angélica Pavão Dimantas

    2003-01-01

    Full Text Available As uveítes anteriores são caracterizadas pela inflamação preponderante do segmento anterior do olho. Hiperemia conjuntival, reação de câmara anterior com células e "flare", precipitados ceráticos e sinéquias posteriores são sinais que compõem o quadro inflamatório. Aspectos clínicos de algumas doenças sistêmicas envolvidas na etiologia das uveítes anteriores serão abordados neste artigo.Anterior uveitis describes a disease predominantly limited to the anterior segment of the eye. Conjunctival hyperemia, anterior chamber cell and flare, keratic precipitates, and iris abnormalities including posterior synechiae characterize the inflammation. This article discusses clinical aspects of the systemic diseases that cause anterior uveitis with review of the literature.

  8. MOONS: A New Powerful Multi-Object Spectrograph for the VLT

    Science.gov (United States)

    Cirasuolo, M.; MOONS Consortium

    2016-10-01

    MOONS (the Multi-Object Optical and Near-infrared Spectrograph) is a third-generation instrument for the ESO Very Large Telescope (VLT). The large collecting area offered by the VLT (8.2 m diameter), combined with the large multiplex and wavelength coverage (optical to near-IR: 0.64 μm - 1.8 μm) of MOONS will provide the European astronomical community with a powerful, unique instrument able to pioneer a wide range of Galactic, Extragalactic and Cosmological studies, and the crucial follow-up for major facilities such as Gaia, VISTA, Euclid and LSST. MOONS has the observational power needed to unveil galaxy formation and evolution over the entire history of the Universe, from stars in our Milky Way, through the redshift desert, and up to the epoch of the very first galaxies and reionization of the Universe at redshifts of z > 8-9, just a few million years after the Big Bang. From five years of observations MOONS will provide high-quality spectra for >3 M stars in our Galaxy and the Local Group, and for 1-2 M galaxies at z >1 (for an SDSS-like survey), promising to revolutionize our understanding of the Universe. The baseline design consists of 1024 fibers, deployable over a field-of-view of ˜500 sq. arcmin, the largest patrol field offered by the Nasmyth focus at the VLT. The total wavelength coverage is 0.64 μm - 1.8 μm with two spectral resolving power settings: in the medium-resolution mode (R˜4,000-6,000) the entire wavelength range is observed simultaneously, while the high-resolution mode will cover simultaneously selected sub-regions: one region with R˜9,000 near the Ca II triplet to measure stellar radial velocities, and part of the H-band at R˜20,000 for precision measurements of chemical abundances.

  9. Uso da flunixina meglumina tópica no tratamento de uveítes em cães

    Directory of Open Access Journals (Sweden)

    Andrade A.L.

    2003-01-01

    Full Text Available Este trabalho teve por objetivo comparar o efeito (uso tópico da flunixina meglumina e da dexametasona no controle da uveíte anterior em cães, por meio de avaliação clínica e pela dosagem de proteínas no humor aquoso. Foram utilizados 17 cães portadores de uveíte anterior de diversas etiologias. Os animais, divididos em dois grupos, foram tratados durante 15 dias. Observou-se maior eficácia da flunixina meglumina na cura clínica das uveítes e na redução significativa da concentração de proteínas no humor aquoso em relação à dexametasona. Concluiu-se que a preparação comercial de uso parenteral pode ser utilizada como colírio no tratamento de doenças inflamatórias da úvea.

  10. Uveítis intermedia: Experiencias terapéuticas Intermediate uveitis: Therapeutic experiences

    Directory of Open Access Journals (Sweden)

    Sandra M. Borges Pérez

    2001-12-01

    Full Text Available Se realizó un estudio descriptivo prospectivo a 50 ojos (41 pacientes con el diagnóstico de uveítis intermedia durante un período de 3 años. Esta patología fue más frecuente en la mujer (58 %, en edades jóvenes (25 a 45 años y en plena actividad laboral. Se presentan complicaciones y dentro de ellas el edema macular cistoide constituye la causa que más afecta la visión. La mejoría de la agudeza visual fue más notable en los pacientes bajo régimen de tratamiento médico acompañado de tratamiento quirúrgico (40 %. El 50 % de los pacientes presentaron recidivas.A descriptive and prospective study of 50 eyes (41 patients with the diagnosis of intermediate uveitis was conducted during 3 years. This pathology was more frequent in women (58 %, in young patients (25-45 years old and among workers. Among the complications, the cystoid macular edema was the main cause of vision affections. The improvement of visual acuity was more remarkable in patients under medical and surgical treatment (40 %. 50 % of the patients had relapses.

  11. VLT/VLTI Second-Generation Instrumentation: Lessons Learned

    Science.gov (United States)

    Gilmozzi, R.; Pasquini, L.; Russell, A.

    2016-12-01

    The five second-generation instruments already delivered for the Very Large Telescope (VLT) represent worthy successors to the first generation of instrumentation development. Despite this success, it is still possible to learn many lessons for the future. A review, preceded by a workshop, on the lessons learned from the second-generation instrumentation for the VLT and VLT Interferometer took place in November 2015, following a previous review twelve years ago on lessons learned from the first-generation instruments. The aim of the workshop was to identify lessons in order to help define/refine good practice and make recommendations for the future. This article briefly reports on the workshop and summarises the findings of the review panel, their recommendations and some of the steps to implement them.

  12. The 8.2 metre primary mirrors of the VLT

    Science.gov (United States)

    Dierickx, P.; Enard, D.; Merkle, F.; Noethe, L.; Wilson, R. N.

    1990-08-01

    The Very Large Telescope (VLT) presently being developed at ESO is described in terms of technological advances which make its use both technically effective and feasible. The VLT capitalizes on advances in materials, polishing techniques, and mirror support systems. The VLT consists of four 8-m alt-az telescopes and a 2-m auxiliary telescope in a single-dish configuration with Zerodur meniscus mirrors passively supported on a lateral system. A discussion of the tradeoffs between glass and metal mirrors is presented, and computerized polishing is described in relation to optical specifications. The mirror is supported with 150 axial and 60 lateral supports with electromechanical actuators to modulate applied force. The active optics concept is employed via the flexibility of the primary mirror, which generates elastomechanical deformations and the position and orientation of the secondary mirror.

  13. VLT/FORS2 observations of the optical counterpart of the isolated neutron star RBS 1774

    CERN Document Server

    Mignani, R P; Turolla, R; Haberl, F; Cropper, M; Motch, C; Treves, A; Zampieri, L

    2011-01-01

    X-ray observations performed with ROSAT led to the discovery of a group (seven to date) of X-ray dim and radio-silent middle-aged isolated neutron stars (a.k.a. XDINSs), which are characterised by pure blackbody spectra (kT~40-100 eV), long X-ray pulsations (P=3-12 s), and appear to be endowed with relatively high magnetic fields, (B~10d13-14 G). RBS 1774 is one of the few XDINSs with a candidate optical counterpart, which we discovered with the VLT. We performed deep observations of RBS 1774 in the R band with the VLT to disentangle a non-thermal power-law spectrum from a Rayleigh-Jeans, whose contributions are expected to be very much different in the red part of the spectrum. We did not detect the RBS 1774 candidate counterpart down to a 3 sigma limiting magnitude of R~27. The constraint on its colour, (B-R)<0.6, rules out that it is a background object, positionally coincident with the X-ray source. Our R-band upper limit is consistent with the extrapolation of the B-band flux (assuming a 3 sigma uncer...

  14. Applications of Tunable Imaging Filters for the VLT

    CERN Document Server

    Jones, H

    2001-01-01

    Tunable imaging filters have been used for a variety of science programmes on the Anglo-Australian and William Herschel Telescopes during the last five years. This contribution describes these novel devices and reviews the science (both Galactic and extragalactic) done with them. Possible strategies for implementing a tunable filter at the VLT are also discussed. Significant scientific potential exists for a tunable filter on the VLT, particularly in the years before such capability becomes available on 8 -- 10 m-class telescopes elsewhere.

  15. Surface composition of Europa based on VLT observations

    Science.gov (United States)

    Ligier, N.; Poulet, F.; Carter, J.

    2016-12-01

    Jupiter's moon Europa may harbor a global salty ocean under an 80-170 km thick outer layer consisting of an icy crust (Anderson et al. 1998). Meanwhile, the 10-50 My old surface, dated by cratering rates (Pappalardo et al. 1999) implies rapid surface recycling and reprocessing that could result in tectonic activity (Kattenhorn et al. 2014) and plumes (Roth et al. 2014). The surface could thus exhibit fingerprints of chemical species, as minerals characteristics of an ocean-mantle interaction and/or organics of exobiological interest, directly originating from the subglacial ocean. In order to re-investigate the composition of Europa's surface, a global mapping campaign of the satellite was performed with the near-infrared integral field spectrograph SINFONI on the Very Large Telescope (VLT) in Chile. The high spectral binning of this instrument (0.5 nm) and large signal noise ratio in comparison to previous observations are adequate to detect sharp absorptions in the wavelength range 1.45-2.45 μm. In addition, the spatially resolved spectra we obtained over five epochs nearly cover the entire surface of Europa with a pixel scale of 12.5 by 25 m.a.s ( 35 by 70 km on Europa's surface), thus permitting a global scale study. Several icy and non-icy compounds were detected and mapped at process likely engendered by the Io plasma torus, the crystalline form is found to be approximately twice as abundant as the amorphous ice based on the analysis of the 1.65 μm band. If the surface is dominated by small and mid-sized water ice grains (25-200 μm), crystalline water-ice grains exhibit spatial inhomogeneities in their distribution. The sulfuric acid hydrate distribution exhibits the typical "bullseye" feature on the trailing hemisphere. The presence of Mg-bearing chlorinated salts (chloride, chlorate, and perchlorate) is supported by linear spectral modeling of the data, while the presence of sulfate salts is challenged. The distribution of some of these species is

  16. VLT imaging of the β Pictoris gas disk

    Science.gov (United States)

    Nilsson, R.; Brandeker, A.; Olofsson, G.; Fathi, K.; Thébault, Ph.; Liseau, R.

    2012-08-01

    Context. Circumstellar debris disks older than a few Myr should be largely devoid of primordial gas remaining from the protoplanetary disk phase. Tracing the origin of observed atomic gas in Keplerian rotation in the edge-on debris disk surrounding the ~12 Myr old star β Pictoris requires more detailed information about its spatial distribution than has previously been acquired by limited slit spectroscopy. Especially indications of asymmetries and presence of Ca ii gas at high disk latitudes call for additional investigation to exclude or confirm its connection to observed dust structures or suggested cometary bodies on inclined eccentric orbits. Aims: We set out to recover a complete image of the Fe i and Ca ii gas emission around β Pic by spatially resolved, high-resolution spectroscopic observations to better understand the morphology and origin of the gaseous disk component. Methods: The multiple fiber facility FLAMES/GIRAFFE at the Very Large Telescope (VLT), with the large integral-field-unit ARGUS, was used to obtain spatially resolved optical spectra (from 385.9 to 404.8 nm) in four regions covering the northeast and southwest side of the disk. Emission lines from Fe i (at 386.0 nm) and Ca ii (at 393.4 and 396.8 nm) were mapped and could be used to fit a parametric function for the disk gas distribution, using a gas-ionisation code for gas-poor debris disks. Results: Both Fe i and Ca ii emission are clearly detected, with the former dominating along the disk midplane, and the latter revealing vertically more extended gas. The surface intensity of the Fe i emission is lower but more extended in the northeast (reaching the 210 AU limit of our observations) than in the southwest, while Ca ii shows the opposite asymmetry. The modelled Fe gas disk profile shows a linear increase in scale height with radius, and a vertical profile that suggests dynamical interaction with the dust. We also qualitatively demonstrate that the Ca ii emission profile can be

  17. SPHERE: A Planet Finder Instrument for the VLT

    NARCIS (Netherlands)

    Beuzit, J.L.; Feldt, M.; Dohlen, K.; Mouillet, D.; Puget, P.; Antichi, J.; Baudoz, P.; Boccaletti, A.; Carbillet, M.; Charton, J.; Claudi, R.; Fusco, T.; Gratton, R.; Henning, T.; Hubin, N.; Joos, F.; Kasper, M.; Langlois, M.; Moutou, C.; Pragt, J.; Rabou, P.; Saisse, M.; Schmid, H.M.; Turatto, M.; Udry, S.; Vakili, F.; Waters, R.; Wildi, F.

    2007-01-01

    Direct detection and spectral characterization of extra-solar planets is one of the most exciting but also one of the most challenging areas in modern astronomy. For its second generation instrumentation on the VLT, ESO has supported two phase A studies for a so-called Planet Finder dedicated instru

  18. The design of the MOONS-VLT spectrometer

    NARCIS (Netherlands)

    Oliva, E.; Diolaiti, E.; Garilli, B.; Gratton, R.; Lorenzetti, D.; Schipani, P.; Scuderi, S.; Vanzella, E.; Cirasuolo, M.; Afonso, J.; Bender, R.; Bonifacio, P.; Kaper, L.; Vanzi, L.; Baffa, C.; Bianco, A.; Bonoli, C.; Bortoletto, F.; Bruno, P.; Carbonaro, L.; Centrone, M.; Cresci, G.; De Caprio, V.; Del Vecchio, C.; Di Marcantonio, P.; Di Paola, A.; D'Alessio, F.; D'Alessandro, M.; D'Orsi, S.; Falcini, G.; Ferruzzi, D.; Fontana, A.; Foppiani, I.; Fumana, M.; Giani, E.; Leone, F.; Li Causi, G.; Lombini, M.; Maiolino, R.; Mannucci, F.; Marty, L.; Miglietta, L.; Munari, M.; Navarro, R.; Origlia, L.; Paioro, L.; Pedichini, F.; Pragt, J.; Randich, S.; Scodeggio, M.; Spano, P.; Speziali, R.; Stuik, R.; Tozzi, A.; Vitali, F.

    2012-01-01

    MOONS is a new conceptual design for a multi-object spectrograph for the ESO Very Large Telescope (VLT) which will provide the ESO astronomical community with a powerful, unique instrument able to serve a wide range of Galactic, Extragalactic and Cosmological studies. The instrument foresees 1000

  19. The science case of the CHEOPS planet finder for VLT

    NARCIS (Netherlands)

    Gratton, R.; Feldt, M.; Schmid, H.M.; Brandner, W.; Hippler, S.; Neuhauser, R.; Quirrenbach, A.; Desidera, S.; Turatto, M.; Stam, D.M.; Hasinger, G.; Turner, M.J.L.

    2004-01-01

    The CHEOPS Planet Finder is one of the proposed second generation instruments for the VLT. Its purpose is to image and characterize giant extrasolar planets in different phases of their evolution: young, warm planets as well as old, cold ones. Imaging the last ones is the most challenging task becau

  20. The design of the MOONS-VLT spectrometer

    NARCIS (Netherlands)

    Oliva, E.; Diolaiti, E.; Garilli, B.; Gratton, R.; Lorenzetti, D.; Schipani, P.; Scuderi, S.; Vanzella, E.; Cirasuolo, M.; Afonso, J.; Bender, R.; Bonifacio, P.; Kaper, L.; Vanzi, L.; Baffa, C.; Bianco, A.; Bonoli, C.; Bortoletto, F.; Bruno, P.; Carbonaro, L.; Centrone, M.; Cresci, G.; De Caprio, V.; Del Vecchio, C.; Di Marcantonio, P.; Di Paola, A.; D'Alessio, F.; D'Alessandro, M.; D'Orsi, S.; Falcini, G.; Ferruzzi, D.; Fontana, A.; Foppiani, I.; Fumana, M.; Giani, E.; Leone, F.; Li Causi, G.; Lombini, M.; Maiolino, R.; Mannucci, F.; Marty, L.; Miglietta, L.; Munari, M.; Navarro, R.; Origlia, L.; Paioro, L.; Pedichini, F.; Pragt, J.; Randich, S.; Scodeggio, M.; Spano, P.; Speziali, R.; Stuik, R.; Tozzi, A.; Vitali, F.

    2012-01-01

    MOONS is a new conceptual design for a multi-object spectrograph for the ESO Very Large Telescope (VLT) which will provide the ESO astronomical community with a powerful, unique instrument able to serve a wide range of Galactic, Extragalactic and Cosmological studies. The instrument foresees 1000 fi

  1. The ESO/VLT 3rd year Type Ia supernova data set from the Supernova Legacy Survey

    CERN Document Server

    Balland, C; Basa, S; Mouchet, M; Howell, D A; Astier, P; Carlberg, R G; Conley, A; Fouchez, D; Guy, J; Hardin, D; Hook, I M; Pain, R; Perrett, K; Pritchet, C J; Regnault, N; Rich, J; Sullivan, M; Antilogus, P; Arsenijevic, V; Du, J Le; Fabbro, S; Lidman, C; Mourao, A; Palanque-Delabrouille, Nathalie; Pécontal, E; Ruhlmann-Kleider, V

    2009-01-01

    We present 139 spectra of 124 Type Ia supernovae (SNeIa) that were observed at the ESO/VLT during the first three years of the Canada-France-Hawai Telescope (CFHT) Supernova Legacy Survey (SNLS). This homogeneous data set is used to test for redshift evolution of SNeIa spectra, and will be used in the SNLS 3rd year cosmological analyses. Spectra have been reduced and extracted with a dedicated pipeline that uses photometric information from deep CFHT Legacy Survey (CFHT-LS) reference images to trace, at sub-pixel accuracy, the position of the supernova on the spectrogram as a function of wavelength. It also separates the supernova and its host light in 60% of cases. The identification of the supernova candidates is performed using a spectrophotometric SNIa model. A total of 124 SNeIa, roughly 50% of the overall SNLS spectroscopic sample, have been identified using the ESO/VLT during the first three years of the survey. Their redshifts range from z=0.149 to z=1.031. The average redshift of the sample is z=0.63...

  2. GRB hosts through cosmic time. VLT/X-Shooter emission-line spectroscopy of 96 γ-ray-burst-selected galaxies at 0.1

    NARCIS (Netherlands)

    T. Krühler; D. Malesani; J.P.U. Fynbo; O.E. Hartoog; J. Hjorth; P. Jakobsson; D.A. Perley; A.. Rossi; P. Schady; S. Schulze; N.R. Tanvir; S.D. Vergani; K. Wiersema; P.M.J. Afonso; J. Bolmer; Z. Cano; S. Covino; V. D’Elia; A. de Ugarte Postigo; R. Filgas; M. Friis; J.F. Graham; J. Greiner; P. Goldoni; A. Gomboc; F. Hammer; J. Japelj; D.A. Kann; L. Kaper; S. Klose; A.J. Levan; G. Leloudas; B. Milvang-Jensen; A. Nicuesa Guelbenzu; E. Palazzi; E. Pian; S. Piranomonte; R. Sánchez-Ramírez; S. Savaglio; J. Selsing; G. Tagliaferri; P.M. Vreeswijk; D.J. Watson; D. Xu

    2015-01-01

    We present data and initial results from VLT/X-Shooter emission-line spectroscopy of 96 galaxies selected by long γ-ray bursts (GRBs) at 0.1 spectra available to date. Most of our GRBs were detected by Swift and 76% are at 0.5

  3. The chemical composition of the galactic H II regions M8 and M17. A revision based on deep vlt echelle spectrophotometry

    Directory of Open Access Journals (Sweden)

    Jorge García-Rojas

    2007-01-01

    Full Text Available Presentamos nuevos datos espectrofotométricos de las regiones H II Galácticas M8 y M17. Los datos se obtuvieron a través del espectrógrafo echelle UVES del VLT en el intervalo entre los 3100 y los 10400 Ă. Medimos las intensidades de 375 y 260 líneas de emisión en M8 y M17, respectivamente, incrementando de forma significativa el número de líneas identificadas en estas nebulosas. La mayoría de las líneas detectadas son permitidas. Calculamos las temperaturas y densidades electrónicas usando diferentes diagnósticos, y determinamos las abundancias iónicas de He+, C++, O+ and O++ a partir de líneas debidas únicamente a recombinación, así como las abundancias de un gran número de iones de diferentes elementos usando líneas de excitación colisional. Obtuvimos estimaciones consistentes de t2 usando diferentes indicadores independientes. Detectamos líneas de emisión de la serie de Balmer de deuterio en M8, hasta DÎ; también mostramos que sus intensidades son consistentes con el hecho de que la fluorescencia del continuo es el principal mecanismo de excitación de estas líneas.

  4. Keck and VLT Observations of Super-damped Lyman-alpha Absorbers at z=2=2.5: Constraints on Chemical Compositions and Physical Conditions

    CERN Document Server

    Kulkarni, Varsha P; Morrison, Sean; Peroux, Celine; Quiret, Samuel; York, Donald G

    2015-01-01

    We report Keck/ESI and VLT/UVES observations of three super-damped Lyman-alpha quasar absorbers with H I column densities log N(HI) >= 21.7 at redshifts z=2-2.5. All three absorbers show similar metallicities (-1.3 to -1.5 dex), and dust depletion of Fe, Ni, and Mn. Two of the absorbers show supersolar [S/Zn] and [Si/Zn]. We combine our results with those for other DLAs to examine trends between N(HI), metallicity, dust depletion. A larger fraction of the super-DLAs lie close to or above the line [X/H]=20.59-log N(HI) in the metallicity vs. N(HI) plot, compared to the less gas-rich DLAs, suggesting that super-DLAs are more likely to be rich in molecules. Unfortunately, our data for Q0230-0334 and Q0743+1421 do not cover H2 absorption lines. For Q1418+0718, some H2 lines are covered, but not detected. CO is not detected in any of our absorbers. For DLAs with log N(HI) 21.7 may have somewhat narrower velocity dispersions delta v_90 than the less gas-rich DLAs, and may arise in cooler and/or less turbulent gas.

  5. Caracterização da uveíte na espondilite anquilosante Characterization of uveitis in ankylosing spondylitis

    Directory of Open Access Journals (Sweden)

    Percival Degrava Sampaio-Barros

    2003-12-01

    Full Text Available OBJETIVO: analisar a apresentação clínica e a evolução da uveíte em uma população de 207 pacientes com espondilite anquilosante (EA. MÉTODOS: estudo retrospectivo (1988-2001 analisando 207 pacientes com o diagnóstico de EA segundo os critérios de Nova York modificados. Todos apresentavam investigação clínica (envolvimento axial e periférico, entesopatias, manifestações extra-articulares e radiológica (sacroilíaca, coluna lombar, dorsal e cervical completas, além da pesquisa do HLA-B27 (com seus respectivos alelos, quando possível. Os dados foram comparados com a presença de uveíte durante o período de seguimento dos pacientes. RESULTADOS: trinta pacientes (14,5% apresentaram 55 episódios de uveíte anterior aguda unilateral durante o seguimento ambulatorial. Vinte e sete pacientes encontravam-se em atividade articular da EA no momento da crise de uveíte, enquanto três pacientes encontravam-se inativos do ponto de vista articular. Um único paciente, em tratamento de tuberculose pulmonar, apresentou um episódio de uveíte posterior. Entre os pacientes com uveíte, houve predomínio de sexo masculino (82,6%, raça caucasóide (77,8%, início da EA na idade adulta (83,1%, HLA-B27 positivo (79,2%, sem história familiar de EA (84,5%. Houve associação estatística entre uveíte e idade de início juvenil (p = 0,0094 e entesopatias aquileana (p = 0,0003 e plantar (p = 0,0067. Nenhum paciente apresentou seqüela ocular grave da uveíte. Dezesseis pacientes fizeram uso de sulfassalazina (1,0 g/dia a 2,0 g/dia, por prazo mínimo de seis meses. CONCLUSÕES: a uveíte anterior aguda foi comum na evolução da EA nesta casuística, estando associada preferencialmente à EA de início juvenil e ao acometimento articular entesopático de membros inferiores.OBJECTIVE: To analyze the clinical picture and outcome of uveitis in a series of 207 patients with ankylosing spondylitis (AS. METHODS: Retrospective study (1988-2001 analyzing

  6. Spectroscopic confirmation of high-redshift supernovae with the ESO VLT

    CERN Document Server

    Lidman, C E; Folatelli, G; Garavini, G; Nobili, S; Aldering, G; Amanullah, R; Antilogus, P; Astier, Pierre; Blanc, G; Burns, M S; Conley, A; Deustua, S E; Doi, M; Ellis, R; Fabbro, S; Fadeev, V; Gibbons, R; Goldhaber, G; Goobar, A; Groom, D E; Hook, I; Kashikawa, N; Kim, A G; Knop, R A; Lee Byung Cheol; Méndez, J; Morokuma, T; Motohara, K; Nugent, P; Pain, R; Perlmutter, S; Prasad, V; Quimby, R; Raux, J; Regnault, N; Ruiz-Lapuente, P; Sainton, G; Schaefer, B E; Schahmaneche, K; Smith, E; Spadafora, A L; Stanishev, V; Walton, N A; Wang, L; Wood-Vasey, W M; Yasuda, N

    2004-01-01

    We present VLT FORS1 and FORS2 spectra of 39 candidate high-redshift supernovae that were discovered as part of a cosmological study using Type Ia supernovae (SNe Ia) over a wide range of redshifts. From the spectra alone, 20 candidates are spectrally classified as SNe Ia with redshifts ranging from z=0.212 to z=1.181. Of the remaining 19 candidates, 1 might be a Type II supernova and 11 exhibit broad supernova-like spectral features and/or have supernova-like light curves. The candidates were discovered in 8 separate ground-based searches. In those searches in which SNe Ia at z ~ 0.5 were targeted, over 80% of the observed candidates were spectrally classified as SNe Ia. In those searches in which SNe Ia with z > 1 were targeted, 4 candidates with z > 1 were spectrally classified as SNe Ia and later followed with ground and space based observatories. We present the spectra of all candidates, including those that could not be spectrally classified as supernova.

  7. Image quality and high contrast improvements on VLT/NACO

    CERN Document Server

    Girard, Julien H V; Mawet, Dimitri; Kasper, Markus; Zins, Gérard; Neichel, Benoît; Kolb, Johann; Christiaens, Valentin; Tourneboeuf, Martin; 10.1117/12.925660

    2012-01-01

    NACO is the famous and versatile diffraction limited NIR imager and spectrograph with which ESO celebrated 10 years of Adaptive Optics at the VLT. Since two years a substantial effort has been put in to understanding and fixing issues that directly affect the image quality and the high contrast performances of the instrument. Experiments to compensate the non-common-path aberrations and recover the highest possible Strehl ratios have been carried out successfully and a plan is hereafter described to perform such measurements regularly. The drift associated to pupil tracking since 2007 was fixed in October 2011. NACO is therefore even better suited for high contrast imaging and can be used with coronagraphic masks in the image plane. Some contrast measurements are shown and discussed. The work accomplished on NACO will serve as reference for the next generation instruments on the VLT, especially those working at the diffraction limit and making use of angular differential imaging (i.e. SPHERE, VISIR, possibly ...

  8. New BVRI photometry results on KBOs from the ESO VLT

    CERN Document Server

    Santos-Sanz, P; Barrera, L; Boehnhardt, H

    2008-01-01

    Photometric surveys of transNeptunian objects (TNOs) and Centaurs have suggested possible correlations between some orbital parameters and surface colors of classical objects, scattered disk objects (SDOs), and Centaurs. However, larger sample sizes are needed in order to corroborate or rule out the possible correlations and find some possible new ones. We use VLT-FORS images through BVRI filters of 32 Kuiper Belt Objects (KBOs) and obtain their colors after proper reduction and calibration. We study the possible correlations merging these new measurements with the VLT published results from the ESO large program and with the latest published results of the Meudon Multicolor Survey via non-parametric statistical tests. We obtain a large dataset of 116 objects (classical, SDOs and Centaurs) and, in addition to confirming most of the correlations and conclusions reached in the literature, some possible new correlations are found. The most interesting ones are some correlations of color vs. orbital parameters fo...

  9. Designing a common real-time controller for VLT applications

    Science.gov (United States)

    Bauvir, Bertrand; Wallander, Anders; Duhoux, Philippe; Huxley, Alexis; Karban, Robert

    2004-09-01

    The increasing number of digital control applications in the context of the VLT, and particularly the VLT Interferometer, brought the need to find a common solution to address the problems of performance and maintainability. Tools for Advanced Control (TAC) aims at helping both control and software engineers in the design and prototyping of real-time control applications by providing them with a set of standard functions and an easy way to combine them to create complex control algorithms. In this paper we describe the software architecture and design of TAC, the VLT standard for digital control applications. Algorithms are described at schematic level and take the form of a set of interconnected function blocks. Periodical execution of the algorithm as well as features like runtime modification of parameters and probing of internal data are also managed by TAC, allowing the application designers to avoid spending time writing low value software code and therefore focus on application-specific concerns. We also summarize the results achieved on the first actual applications using TAC, to manage real-time control or digital signal processing algorithms, currently deployed and being commissioned at Paranal Observatory.

  10. Ionization processes in a local analogue of distant clumpy galaxies: VLT MUSE IFU spectroscopy and FORS deep images of the TDG NGC 5291N

    CERN Document Server

    Fensch, J; Weilbacher, P M; Boquien, M; Zackrisson, E

    2016-01-01

    We present IFU observations with MUSE@VLT and deep imaging with FORS@VLT of a dwarf galaxy recently formed within the giant collisional HI ring surrounding NGC 5291. This TDG-like object has the characteristics of typical z=1-2 gas-rich spiral galaxies: a high gas fraction, a rather turbulent clumpy ISM, the absence of an old stellar population, a moderate metallicity and star formation efficiency. The MUSE spectra allow us to determine the physical conditions within the various complex substructures revealed by the deep optical images, and to scrutinize at unprecedented spatial resolution the ionization processes at play in this specific medium. Starburst age, extinction and metallicity maps of the TDG and surrounding regions were determined using the strong emission lines Hbeta, [OIII], [OI], [NII], Halpha and [SII] combined with empirical diagnostics. Discrimination between different ionization mechanisms was made using BPT--like diagrams and shock plus photoionization models. Globally, the physical condit...

  11. SWEET-Cat update and FASMA. A new minimization procedure for stellar parameters using high-quality spectra

    Science.gov (United States)

    Andreasen, D. T.; Sousa, S. G.; Tsantaki, M.; Teixeira, G. D. C.; Mortier, A.; Santos, N. C.; Suárez-Andrés, L.; Delgado-Mena, E.; Ferreira, A. C. S.

    2017-04-01

    Context. Thanks to the importance that the star-planet relation has to our understanding of the planet formation process, the precise determination of stellar parameters for the ever increasing number of discovered extrasolar planets is of great relevance. Furthermore, precise stellar parameters are needed to fully characterize the planet properties. It is thus important to continue the efforts to determine, in the most uniform way possible, the parameters for stars with planets as new discoveries are announced. Aims: In this paper we present new precise atmospheric parameters for a sample of 50 stars with planets. The results are presented in the catalogue: SWEET-Cat. Methods: Stellar atmospheric parameters and masses for the 50 stars were derived assuming local thermodynamic equilibrium and using high-resolution and high signal-to-noise spectra. The methodology used is based on the measurement of equivalent widths with ARES2 for a list of iron lines. The line abundances were derived using MOOG. We then used the curve of growth analysis to determine the parameters. We implemented a new minimization procedure which significantly improves the computational time. Results: The stellar parameters for the 50 stars are presented and compared with previously determined literature values. For SWEET-Cat, we compile values for the effective temperature, surface gravity, metallicity, and stellar mass for almost all the planet host stars listed in the Extrasolar Planets Encyclopaedia. This data will be updated on a continuous basis. The data can be used for statistical studies of the star-planet correlation, and for the derivation of consistent properties for known planets. Based on observations collected at the La Silla Observatory, ESO (Chile), with FEROS/2.2 m (run 2014B/020), with UVES/VLT at the Cerro Paranal Observatory (runs ID 092.C-0695, 093.C-0219, 094.C-0367, 095.C-0324, and 096.C-0092), and with FIES/NOT at Roque de los Muchachos (Spain; runs ID 14AF14 and 53

  12. Workshop “Science with the VLT in the ELT Era”

    CERN Document Server

    Astrophysics and Space Science Proceedings

    2008-01-01

    The Workshop ‘Science with the VLT in the ELT era’ was organised by ESO as a forum for the astronomical community to debate its expected future use of ESO’s Very Large Telescope ( and its VLTI interferometric mode) when other facilities such as ALMA, JWST and, hopefully, at least one extremely large 30-40m class telescope will be operating. VLT/I science highlights were presented, future science priorities argued, synergies between the VLT and the future facilities confirmed and specific new VLT/I instruments proposed.

  13. The ESO UVES Advanced Data Products Quasar Sample-V. Identifying the Galaxy Counterpart to the sub-Damped Ly-alpha System towards Q2239-2949

    CERN Document Server

    Zafar, Tayyaba; Péroux, Céline; Quiret, Samuel; Fynbo, Johan P U; Ledoux, Cédric; Deharveng, Jean-Michel

    2016-01-01

    Gas flows in and out of galaxies are one of the key unknowns in todays' galaxy evolution studies. Because gas flows carry mass, energy and metals, they are believed to be closely connected to the star formation history of galaxies. Most of these processes take place in the circum-galactic medium (CGM) which remains challenging to observe in emission. A powerful tool to study the CGM gas is offered by combining observations of the gas traced by absorption lines in quasar spectra with detection of the stellar component of the same absorbing-galaxy. To this end, we have targeted the zabs=1.825 sub-Damped Ly-alpha absorber (sub-DLA) towards the zem=2.102 quasar 2dF J 223941.8-294955 (hereafter Q2239-2949) with the ESO VLT/X-Shooter spectrograph. Our aim is to investigate the relation between its properties in emission and in absorption. The derived metallicity of the sub-DLA with log N(HI) = 19.84+/-0.14 cm-2 is [M/H] >-0.75. Using the Voigt profile optical depth method, we measure Delta_v90(FeII)=64 kms-1. The s...

  14. VLT/X-shooter survey of near-infrared diffuse interstellar bands

    CERN Document Server

    Cox, N L J; Kaper, L; Ehrenfreund, P; Foing, B H; Ochsendorf, B B; van Hooff, S H M; Salama, F

    2014-01-01

    This paper presents a spectral survey of diffuse interstellar bands (DIBs) in the NIR range, from 0.9 to 2.5 micron. The observations were designed to detect new DIBs, confirm previously proposed NIR DIBs, and characterise their behaviour with respect to known line-of-sight properties (including the optical DIBs present in our spectra). X-shooter at the VLT was used to obtained medium-resolution spectra of eight known DIB targets and one telluric reference star. In addition to the known 9577, 9632, 11797, and 13175 Angstroms NIR DIBs, we confirm 9 out of the 13 NIR DIBs that were presented by Geballe and co-workers in 2011. Furthermore, we report 12 new NIR DIB candidates. The strengths of the strongest NIR DIBs show a general correlation with reddening, E(B-V), but with a large scatter. Several NIR DIBs are more strongly correlated with the 5780 Angstroms DIB strength than with E(B-V); this is especially the case for the 15268 Angstroms DIB. The NIR DIBs are strong: the summed equivalent widths of the five s...

  15. Uveitis in dogs infected with Ehrlichia canis Uveíte em cães infectados com Ehrlichia canis

    Directory of Open Access Journals (Sweden)

    Arianne Pontes Oriá

    2004-08-01

    Full Text Available Uveitis is a common disease in dogs with a multitude of causes, one of them being ehrlichiosis. This article reviews several uveitis etiologies, as well as the important aspects of canine ehrlichiosis, including its diagnosis and the main ophthalmic signs presented in these cases. It also reports the therapy that should be used.As uveítes, que se constituem em oftalmopatias comuns entre os cães, decorrem de inúmeras causas. Em nosso meio, destaca-se a erliquiose. Este artigo discute as várias causas da enfermidade ocular, bem como aspectos importantes da enfermidade parasitária, incluindo os sinais, o diagnóstico e o tratamento.

  16. VLT Detects First Superstorm on Exoplanet

    Science.gov (United States)

    2010-06-01

    fingerprints, observing the planet for about five hours, as it passed in front of its star. "CRIRES is the only instrument in the world that can deliver spectra that are sharp enough to determine the position of the carbon monoxide lines at a precision of 1 part in 100 000," says another team member Remco de Kok. "This high precision allows us to measure the velocity of the carbon monoxide gas for the first time using the Doppler effect." The astronomers achieved several other firsts. They directly measured the velocity of the exoplanet as it orbits its home star. "In general, the mass of an exoplanet is determined by measuring the wobble of the star and assuming a mass for the star, according to theory. Here, we have been able to measure the motion of the planet as well, and thus determine both the mass of the star and of the planet," says co-author Ernst de Mooij. Also for the first time, the astronomers measured how much carbon is present in the atmosphere of this planet. "It seems that H209458b is actually as carbon-rich as Jupiter and Saturn. This could indicate that it was formed in the same way," says Snellen. "In the future, astronomers may be able to use this type of observation to study the atmospheres of Earth-like planets, to determine whether life also exists elsewhere in the Universe." More information This research was presented in a paper that appears this week in the journal Nature: "The orbital motion, absolute mass, and high-altitude winds of exoplanet HD209458b", by I. Snellen et al. The team is composed of Ignas A. G. Snellen and Ernst J. W. de Mooij, (Leiden Observatory, The Netherlands), Remco J. de Kok (SRON, Utrecht, The Netherlands), and Simon Albrecht (Massachusetts Institute of Technology, USA). ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France

  17. ESPRESSO: the ultimate rocky exoplanets hunter for the VLT

    Science.gov (United States)

    Mégevand, Denis; Zerbi, Filippo M.; Cabral, Alexandre; Di Marcantonio, Paolo; Amate, Manuel; Pepe, Francesco; Cristiani, Stefano; Rebolo, Rafael; Santos, Nuno C.; Dekker, Hans; Abreu, Manuel; Affolter, Michael; Avila, Gerardo; Baldini, Veronica; Bristow, Paul; Broeg, Christopher; Carvas, Pedro; Cirami, Roberto; Coelho, João.; Comari, Maurizio; Conconi, Paolo; Coretti, Igor; Cupani, Guido; D'Odorico, Valentina; De Caprio, Vincenzo; Delabre, Bernard; Figueira, Pedro; Fleury, Michel; Fragoso, Ana; Genolet, Ludovic; Gomes, Ricardo; Gonzalez Hernandez, Jonay; Hughes, Ian; Iwert, Olaf; Kerber, Florian; Landoni, Marco; Lima, Jorge; Lizon, Jean-Louis; Lovis, Christophe; Maire, Charles; Mannetta, Marco; Martins, Carlos; Moitinho, André; Molaro, Paolo; Monteiro, Manuel; Rasilla, José Luis; Riva, Marco; Santana Tschudi, Samuel; Santin, Paolo; Sosnowska, Danuta; Sousa, Sergio; Spanò, Paolo; Tenegi, Fabio; Toso, Giorgio; Vanzella, Eros; Viel, Matteo; Zapatero Osorio, Maria Rosa

    2012-09-01

    ESPRESSO, the VLT rocky exoplanets hunter, will combine the efficiency of modern echelle spectrograph with extreme radial-velocity precision. It will be installed at Paranal on ESO's VLT in order to achieve a gain of two magnitudes with respect to its predecessor HARPS, and the instrumental radial-velocity precision will be improved to reach 10 cm/s level. We have constituted a Consortium of astronomical research institutes to fund, design and build ESPRESSO on behalf of and in collaboration with ESO, the European Southern Observatory. The project has passed the preliminary design review in November 2011. The spectrograph will be installed at the so-called "Combined Coudé Laboratory" of the VLT, it will be linked to the four 8.2 meters Unit Telescopes (UT) through four optical "Coudé trains" and will be operated either with a single telescope or with up to four UTs. In exchange of the major financial and human effort the building Consortium will be awarded with guaranteed observing time (GTO), which will be invested in a common scientific program. Thanks to its characteristics and the ability of combining incoherently the light of 4 large telescopes, ESPRESSO will offer new possibilities in many fields of astronomy. Our main scientific objectives are, however, the search and characterization of rocky exoplanets in the habitable zone of quiet, near-by G to M-dwarfs, and the analysis of the variability of fundamental physical constants. In this paper, we present the ambitious scientific objectives, the capabilities of ESPRESSO, the technical solutions for the system and its subsystems, enlightening the main differences between ESPRESSO and its predecessors. The project aspects of this facility are also described, from the consortium and partnership structure to the planning phases and milestones.

  18. VLT telescope control software: status, development, and lessons learned

    Science.gov (United States)

    Wirenstrand, Krister

    2003-02-01

    The four 8m VLT telescopes on Paranal are now in full science operation, and they all deliver good results with very small technical downtimes. Of course, many factors are contributing to these results, and also the telescope control software has its share. It has demonstrated to be robust and reliable and also flexible and expandable. In the four years since First Light of the first VLT telescope, this software has been continuously maintained and developed, for improvements on the 8m telescopes but also for use on other telescopes. In addition to the 8m ones, another three telescopes, using applicable parts of the same software, are in operation on Paranal: the 350- mm seeing monitor and two 400-mm siderostats. And the process continues: in the beginning of 2003 the first of three 1.8m Auxiliary Telescopes for the VLT Interferometer will be installed; the control software to 80% being the same as for the 8m telescopes, but with additional devices and control functionality. Another three ESO telescopes on La Silla are also using the same software, as well as two wide field telescopes for Paranal that are now in the design and manufacturing phase. In this development process, and in particular after first installation, we have learned lessons in many areas of software project work. System design and engineering, standardization, tools, testing: these are example areas where there is always room for improvement. Another lesson learned is the importance of the concept of Commissioning, i.e. the work to take the telescope from "integrated" to "working"! What the future of telescope control software will be, that we don't know, but we are working on it! And we try to keep an evolutionary approach, taking advantage of the lessons learned.

  19. ESO Council Decides to Continue VLT Project at Paranal

    Science.gov (United States)

    1994-08-01

    The Council [1] of the European Southern Observatory has met in extraordinary session at the ESO Headquarters in Garching near Munich on August 8 and 9, 1994. The main agenda items were concerned with the recent developments around ESO's relations with the host state, the Republic of Chile, as well as the status of the organisation's main project, the 16-metre equivalent Very Large Telescope (VLT) which will become the world's largest optical telescope. Council had decided to hold this special meeting [2] because of various uncertainties that have arisen in connection with the implementation of the VLT Project at Cerro Paranal, approx. 130 kilometres south of Antofagasta, capital of the II Region in Chile. Following continued consultations at different levels within the ESO member states and after careful consideration of all aspects of the current situation - including various supportive actions by the Chilean Government as well as the incessive attacks against this international organisation from certain sides reported in the media in that country - Council took the important decision to continue the construction of the VLT Observatory at Paranal, while at the same time requesting the ESO Management to pursue the ongoing studies of alternative solutions. THE COUNCIL DECISIONS In particular, the ESO Council took note of recent positive developments which have occurred since the May 1994 round of discussions with the Chilean authorities in Santiago. The confirmation of ESO's immunities as an International Organization in Chile, contained in a number of important statements and documents, is considered a significant step by the Chilean Government to insure to ESO the unhindered erection and later operation of the VLT on Paranal. Under these circumstances and in order to maintain progress on the VLT project, the ESO Council authorized the ESO Management to continue the on-site work at Paranal. Council also took note of the desire expressed by the Chilean Government

  20. VLT/NACO observations of Neptune's ring arcs

    Science.gov (United States)

    Renner, S.; Sicardy, B.; Souami, D.; Dumas, C.

    2011-10-01

    We present NACO adaptative optics observations of Neptune's ring arcs at 2.2 μm (K band), taken with the VLT-Yepun telescope in August 2007. We give improved mean motion values for the arcs and Galatea, thus confirming the mismatch between the arcs' position and the location of the 42:43 corotation inclination resonance. We compare the photometry of the arcs with previous observations. We finally use the data to constrain the masses and positions of the coorbital satellites which could confine the arcs, while allowing a slow evolution of the system.

  1. VLT instrumentation control: the collaboration of OATs with ESO

    Science.gov (United States)

    Santin, P.

    The collaboration of the Astrophysics Technology Group (ATG) of the Astronomical Observatory of Trieste with ESO will be presented. It may be considered as an example of a good practice in the collaboration of a peripheral Institute with ESO. Started in 1985, it spans almost all the time since Italy joined ESO in 1982. The Trieste Astrophysics Technology Group (ATG) participated in many technological enterprise of ESO, from Remote Observing to VLT instrumentation and to ALMA ACS, and is now looking for the challenging E-ELT.

  2. VLT spectroscopy of massive stars in NGC55

    Directory of Open Access Journals (Sweden)

    N. Castro

    2007-01-01

    Full Text Available We present the first spectroscopy study of massive stars in NGC55. The data, taken with VLT-FORS2 allow us to provide spectral classification for 200 objects located through- out the galaxy. From this sample, suitable B-type supergiants are chosen for subsequent higher resolution spectroscopic observations that will enable a quantitative study. The stellar abundances will be a key point in the study of galaxy chemical evolution. We also discuss how GTC-OSIRIS can be a valuable tool for similar studies.

  3. A valiant little terminal: A VLT user's manual

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, A.

    1990-12-01

    This report is a manual for the valiant little terminal. Information covered in this report is as follow: an introduction to VLT; installation; starting up; text screen menus; graphics screen menus; introduction to VLT's scripting facility; quick reference section; and troubleshooting.

  4. MOONS: the Multi-Object Optical and Near-infrared Spectrograph for the VLT

    NARCIS (Netherlands)

    M. Cirasuolo; . et al.; L. Kaper; B. Lemasle

    2014-01-01

    MOONS is a new Multi-Object Optical and Near-infrared Spectrograph selected by ESO as a third generation instrument for the Very Large Telescope (VLT). The grasp of the large collecting area offered by the VLT (8.2m diameter), combined with the large multiplex and wavelength coverage (optical to nea

  5. The Great Observatories Origins Deep Survey VLT/FORS2 Spectroscopy in the GOODS-South Field: Part II

    CERN Document Server

    Vanzella, E; Dickinson, M; Kuntschner, H; Nonino, M; Rettura, A; Rosati, P; Vernet, J; Césarsky, C J; Ferguson, H C; Fosbury, R A E; Giavalisco, M; Haase, J; Moustakas, L A; Popesso, P; Renzini, A; Stern, D; Team, the GOODS

    2006-01-01

    We present the second campaign of the ESO/GOODS program of spectroscopy of faint galaxies in the Chandra Deep Field South (CDF-S). Objects were selected as candidates for VLT/FORS2 observations primarily based on the expectation that the detection and measurement of their spectral features would benefit from the high throughput and spectral resolution of FORS2. The reliability of the redshift estimates is assessed using diagnostic diagrams and comparing the results with public data. 807 spectra of 652 individual targets have been obtained in service mode with the FORS2 spectrograph at the ESO/VLT, providing 501 redshift determinations. The typical redshift uncertainty is estimated to be sigma_z ~ 0.0009. Galaxies have been color selected in a way that the resulting redshift distribution typically spans two redshift domains: from z=0.5 to 2 and z=3.5 to 6.2. In particular, 94 B435-,V606-,i775-"dropout" Lyman break galaxies have been observed, yielding redshifts for 64 objects in the interval 3.4

  6. VizieR Online Data Catalog: Reflectance spectra of 12 Trojans and Hildas (Marsset+, 2014)

    Science.gov (United States)

    Marsset, M.; Vernazza, P.; Gourgeot, F.; Dumas, C.; Birlan, M.; Lamy, P.; Binzel, R. P.

    2014-07-01

    We present 17 reflectance spectra of 12 high albedo (pv>0.14) Trojans (8 objects) and Hildas (4 objects) obtained with the ESO/VLT Echelle spectrograph X-SHOOTER in the 0.3-2.2um spectral range (14 spectra) and with the NASA/IRTF spectrograph SpeX in the 0.8-2.5um spectral range (3 spectra). X-SHOOTER spectra were normalized to unity at 0.55um and SpeX spectra were normalized to unity at 2.2um . The spectra presented in this work were collected between April and December 2013. (18 data files).

  7. AVES: an adaptive optics visual echelle spectrograph for the VLT

    Science.gov (United States)

    Pasquini, Luca; Delabre, Bernard; Avila, Gerardo; Bonaccini, Domenico

    1998-07-01

    We present the preliminary study of a low cost, high performance spectrograph for the VLT, for observations in the V, R and I bands. This spectrograph is meant for intermediate (R equals 16,000) resolution spectroscopy of faint (sky and/or detector limited) sources, with particular emphasis on the study of solar-type (F-G) stars belonging to the nearest galaxies and to distant (or highly reddened) galactic clusters. The spectrograph is designed to use the adaptive optics (AO) systems at the VLT Telescope. Even if these AO systems will not provide diffraction limited images in the V, R and I bands, the photon concentration will still be above approximately 60% of the flux in an 0.3 arcsecond aperture for typical Paranal conditions. This makes the construction of a compact, cheap and efficient echelle spectrograph possible. AVES will outperform comparable non adaptive optic instruments by more than one magnitude for sky- and/or detector-limited observations, and it will be very suitable for observations in crowded fields.

  8. Enfermedades sistémicas no infecciosas y uveítis Non-infectious systemic diseases and uveitis

    Directory of Open Access Journals (Sweden)

    D. Díaz-Valle

    2008-01-01

    Full Text Available La uveítis se define como la inflamación del tracto uveal, aunque en la práctica clínica hace referencia a cualquier proceso inflamatorio intraocular. El origen de esta inflamación puede atribuirse a un mecanismo endógeno, ya sea formando parte de una enfermedad sistémica (sarcoidosis, enfermedad de Behçet, esclerosis múltiple, síndrome de Vogt-Koyanagi-Harada, etc. o de forma ocular aislada. En muchas ocasiones, la enfermedad ocular constituye la forma de comienzo de una enfermedad sistémica. Por otra parte, la afectación ocular constituye, en ocasiones, la principal causa de morbilidad derivada de la enfermedad, por lo que su diagnóstico y tratamiento precoz son de la máxima importancia para evitar secuelas irreversibles. En este artículo se revisan los aspectos clínicos, diagnósticos y terapéuticos más relevantes de la afectación ocular en el contexto clínico de las enfermedades sistémicas no infecciosas más comúnmente asociadas a uveítis.Uveitis can be defined as any inflammation affecting the uveal tract, although in clinical practice this term includes any intraocular inflammatory event. The etiology of this inflammation can be related to an endogenous mechanism in the clinical course of a systemic disease (sarcoidosis, Behçet’s disease, multiple sclerosis, Vogt-Koyanagi-Harada disease, etc., or an isolated ocular entity. Sometimes, ocular inflammation is the initial manifestation of an undiagnosed systemic disease. On the other hand, ocular involvement could be the main cause of morbidity of the disease, and early diagnosis and treatment is an important issue in order to avoid irreversible ocular damage. In this article, the authors review some relevant clinical, diagnostic and therapeutic topics related to the most common non-infectious systemic diseases associated with uveitis.

  9. Spectral analysis of Uranus' 2014 bright storm with VLT/SINFONI

    CERN Document Server

    Irwin, Patrick G J; Read, Peter L; Tice, Dane; de Pater, Imke; Orton, Glenn S; Teanby, Nicholas A; Davis, Gary R

    2015-01-01

    An extremely bright storm system observed in Uranus' atmosphere by amateur observers in September 2014 triggered an international campaign to observe this feature with many telescopes across the world. Observations of the storm system in the near infrared were acquired in October and November 2014 with SINFONI on ESO's Very Large Telescope (VLT) in Chile. SINFONI is an Integral Field Unit spectrometer returning 64x64 pixel images with 2048 wavelengths. Image cubes in the H-band (1.43 - 1.87 microns) were obtained at spatial resolutions of ~0.1". The observations show that the centre of the storm feature shifts markedly with increasing altitude, moving in the retrograde direction and slightly poleward with increasing altitude. We also see a faint 'tail' of more reflective material to the immediate south of the storm, which again trails in the retrograde direction. The observed spectra were analysed with the radiative transfer and retrieval code, NEMESIS. We find that the storm is well-modelled using either two...

  10. Meridional variation in tropospheric methane on Titan observed with AO spectroscopy at Keck and VLT

    CERN Document Server

    Ádámkovics, Máté; Hayes, Alexander G; Rojo, Patricio M; Corlies, Paul; Barnes, Jason W; Ivanov, Valentin D; Brown, Robert H; Baines, Kevin H; Buratti, Bonnie J; Clark, Roger N; Nicholson, Philip D; Sotin, Christophe

    2015-01-01

    The spatial distribution of the tropospheric methane on Titan was measured using near-infrared spectroscopy. Ground-based observations at 1.5$\\mu{\\rm m}$ (H-band) were performed during the same night using instruments with adaptive optics at both the W. M. Keck Observatory and at the Paranal Observatory on 17 July 2014 UT. The integral field observations with SINFONI on the VLT covered the entire H-band at moderate resolving power, $R=\\lambda/\\Delta\\lambda\\approx1,500$, while the Keck observations were performed with NIRSPAO near 1.55254$\\mu{\\rm m}$ at higher resolution, $R\\approx25,000$. The moderate resolution observations are used for flux calibration and for the determination of model parameters that can be degenerate in the interpretation of high resolution spectra. Line-by-line calculations of CH$_4$ and CH$_3$D correlated $k$ distributions from the HITRAN 2012 database were used, which incorporate revised line assignments near 1.5$\\mu{\\rm m}$. We fit the surface albedo and aerosol distributions in the ...

  11. Mid-infrared imaging of 25 local AGN with VLT-VISIR

    CERN Document Server

    Horst, Hannes; Gandhi, Poshak; Smette, Alain

    2009-01-01

    Aims. High angular resolution N-band imaging is used to discern the torus of active galactic nuclei (AGN) from its environment in order to allow a comparison of its mid-infrared properties to the expectations of the unified scenario for AGN. Methods. We present VLT-VISIR images of 25 low-redshift AGN of different Seyfert types, as well as N-band SEDs of 20 of them. In addition, we compare our results for 19 of them to Spitzer IRS spectra. Results. We find that at a resolution of ~ 0.35", all the nuclei of our observed sources are point-like, except for 2 objects whose extension is likely of instrumental origin. For 3 objects, however, we observed additional extended circumnuclear emission, even though our observational strategy was not designed to detect it. Comparison of the VISIR photometry and Spitzer spectrophotometry indicates that the latter is affected by extended emission in at least 7 out of 19 objects and the level of contamination is (0.20 ~ 0.85) * F_IRS. In particular, the 10 um silicate emission...

  12. The ESO UVES Advanced Data Products quasar sample - V. Identifying the galaxy counterpart to the sub-damped Lyα system towards Q 2239-2949

    Science.gov (United States)

    Zafar, Tayyaba; Møller, Palle; Péroux, Céline; Quiret, Samuel; Fynbo, Johan P. U.; Ledoux, Cédric; Deharveng, Jean-Michel

    2017-02-01

    Gas flows in and out of galaxies are one of the key unknowns in today's galaxy evolution studies. Because gas flows carry mass, energy, and metals, they are believed to be closely connected to the star formation history of galaxies. Most of these processes take place in the circum-galactic medium (CGM) which remains challenging to observe in emission. A powerful tool to study the CGM gas is offered by combining observations of the gas traced by absorption lines in quasar spectra with detection of the stellar component of the same absorbing-galaxy. To this end, we have targeted the zabs = 1.825 sub-damped Lyα absorber (sub-DLA) towards the zem = 2.102 quasar 2dF J 223941.8-294955 (hereafter Q 2239-2949) with the ESO VLT/X-Shooter spectrograph. Our aim is to investigate the relation between its properties in emission and in absorption. The derived metallicity of the sub-DLA with log N(H I) = 19.84 ± 0.14 cm-2 is [M/H] > -0.75. Using the Voigt profile optical depth method, we measure Δv90(Fe II) = 64 km s-1. The sub-DLA galaxy counterpart is located at an impact parameter of 2{^''.}4 ± 0{^''.}2 (20.8 ± 1.7 kpc at z = 1.825). We have detected Lyα and marginal [O II] emissions. The mean measured flux of the Lyα line is FLy α ∼ 5.7 × 10-18 erg s-1 cm-2 Å-1, corresponding to a dust uncorrected SFR of ∼0.13 M⊙ yr-1.

  13. The ESO UVES Advanced Data Products Quasar Sample - III. Evidence of Bimodality in the [N/alpha] Distribution

    CERN Document Server

    Zafar, Tayyaba; Peroux, Celine; Molaro, Paolo; D'Odorico, Valentina; Vladilo, Giovanni; Popping, Attila

    2014-01-01

    We report here a study of nitrogen and $\\alpha$-capture element (O, S, and Si) abundances in 18 Damped Ly$\\alpha$ Absorbers (DLAs) and sub-DLAs drawn from the ESO-UVES Advanced Data Products (EUADP) database. We report 9 new measurements, 5 upper and 4 lower limits of nitrogen that when compiled with available nitrogen measurements from the literature makes a sample of 108 systems. The extended sample presented here confirms the [N/$\\alpha$] bimodal behaviour suggested in previous studies. Three-quarter of the systems show $\\langle$[N/$\\alpha$]$\\rangle=-0.85$ ($\\pm$0.20 dex) and one-quarter ratios are clustered at $\\langle$[N/$\\alpha$]$\\rangle= -1.41$ ($\\pm$0.14 dex). The high [N/$\\alpha$] plateau is consistent with the HII regions of dwarf irregular and blue compact dwarf galaxies although extended to lower metallicities and could be interpreted as the result of a primary nitrogen production by intermediate mass stars. The low [N/$\\alpha$] values are the lowest ever observed in any astrophysical site. In spi...

  14. The ESO UVES Advanced Data Products Quasar Sample - II. Cosmological Evolution of the Neutral Gas Mass Density

    CERN Document Server

    Zafar, Tayyaba; Popping, Attila; Milliard, Bruno; Deharveng, Jean-Michel; Frank, Stephan

    2013-01-01

    Quasar foreground damped absorbers, associated with HI-rich galaxies allow to estimate the neutral gas mass over cosmic time, which is a possible indicator of gas consumption as star formation proceeds. The DLAs and sub-DLAs are believed to contain a large fraction of neutral gas mass in the Universe. In Paper I of the series, we present the results of a search for DLAs and sub-DLAs in the ESO-UVES Advanced Data Products dataset of 250 quasars. Here we use an unbiased sub-sample of sub-DLAs from this dataset. We build a subset of 122 quasars ranging from 1.5

  15. Hubble and ESO's VLT provide unique 3D views of remote galaxies

    Science.gov (United States)

    2009-03-01

    Astronomers have obtained exceptional 3D views of distant galaxies, seen when the Universe was half its current age, by combining the twin strengths of the NASA/ESA Hubble Space Telescope's acute eye, and the capacity of ESO's Very Large Telescope to probe the motions of gas in tiny objects. By looking at this unique "history book" of our Universe, at an epoch when the Sun and the Earth did not yet exist, scientists hope to solve the puzzle of how galaxies formed in the remote past. ESO PR Photo 10a/09 A 3D view of remote galaxies ESO PR Photo 10b/09 Measuring motions in 3 distant galaxies ESO PR Video 10a/09 Galaxies in collision For decades, distant galaxies that emitted their light six billion years ago were no more than small specks of light on the sky. With the launch of the Hubble Space Telescope in the early 1990s, astronomers were able to scrutinise the structure of distant galaxies in some detail for the first time. Under the superb skies of Paranal, the VLT's FLAMES/GIRAFFE spectrograph (ESO 13/02) -- which obtains simultaneous spectra from small areas of extended objects -- can now also resolve the motions of the gas in these distant galaxies (ESO 10/06). "This unique combination of Hubble and the VLT allows us to model distant galaxies almost as nicely as we can close ones," says François Hammer, who led the team. "In effect, FLAMES/GIRAFFE now allows us to measure the velocity of the gas at various locations in these objects. This means that we can see how the gas is moving, which provides us with a three-dimensional view of galaxies halfway across the Universe." The team has undertaken the Herculean task of reconstituting the history of about one hundred remote galaxies that have been observed with both Hubble and GIRAFFE on the VLT. The first results are coming in and have already provided useful insights for three galaxies. In one galaxy, GIRAFFE revealed a region full of ionised gas, that is, hot gas composed of atoms that have been stripped of

  16. Estudo da prevalência das uveítes em hospital oftalmológico terciário em Teresina, Piauí, Brasil

    Directory of Open Access Journals (Sweden)

    Leonardo Pinheiro Teixeira

    2016-06-01

    Full Text Available RESUMO Objetivo: analisar a prevalência das uveítes em pacientes atendidos em um serviço oftalmológico terciário em Teresina, Piauí. Métodos: estudo retrospectivo baseado em prontuários de pacientes atendidos nesse serviço. Foram descritos: gênero, faixa etária, procedência, doença de base, diagnóstico anatômico, aspecto clínico e tempo de evolução. Resultados: foram incluídos 403 prontuários constatando-se que a cada 1000 pacientes atendidos neste serviço, 3,2 tinham uveíte.A idade média dos pacientes foi de 42 anos, tanto o gênero feminino (50,6% quanto o gênero masculino (49,4% foram acometidos similarmente, com 61,5% dos pacientes provenientes da capital. A doença de base mais frequente foi a toxoplasmose, seguida das uveítes idiopáticas apenas com manifestações oculares. Quanto à classificação anatômica, 49,6% foram posteriores e 3,5% foram intermediárias. Em relação ao aspecto clínico, 64% foram granulomatosas, 24,8% não-granulomatosas e 11,2% não foram classificáveis. Segundo a evolução clínica, 41,4% foram agudas, seguidas de 30,8% crônicas, 14,4% recorrentes e em 13,4% os pacientes não foi feito o acompanhamento. Conclusão: pudemos constatar que para cada 1000 pacientes atendidos neste serviço 3,2 tinham uveíte, apresentando-se a toxoplasmose como importante fonte de uveíte neste serviço.

  17. Calibration strategy of the pyramid wavefront sensor module of ERIS with the VLT deformable secondary mirror

    Science.gov (United States)

    Riccardi, A.; Briguglio, R.; Pinna, E.; Agapito, G.; Quiros-Pacheco, F.; Esposito, S.

    2012-07-01

    ERIS is a new Adaptive Optics Instrument for the Adaptive Optics Facility of the VLT that foresees, in its design phase, a Pyramid Wavefront Sensor Module (PWM) to be used with the VLT Deformable Secondary Mirror (VLT-DSM) as corrector. As opposite to the concave secondary mirrors currently in use (e.g. at LBT), VLT-DSM is convex and calibration of the interaction matrix (IM) between the PWM and the DSM is not foreseen on-telescope during day-time. In this paper different options of calibration are evaluated and compared with particular attention on the synthetic evaluation and on-sky calibration of the IM. A trade-off of the calibration options, the optimization techniques and the related validation with numerical simulations are also provided.

  18. Two VLT 8.2-m Unit Telescopes in Action

    Science.gov (United States)

    1999-04-01

    Visitors at ANTU - Astronomical Images from KUEYEN The VLT Control Room at the Paranal Observatory is becoming a busy place indeed. From here, two specialist teams of ESO astronomers and engineers now operate two VLT 8.2-m Unit Telescopes in parallel, ANTU and KUEYEN (formerly UT1 and UT2, for more information about the naming and the pronunciation, see ESO Press Release 06/99 ). Regular science observations have just started with the first of these giant telescopes, while impressive astronomical images are being obtained with the second. The work is hard, but the mood in the control room is good. Insiders claim that there have even been occasions on which the groups have had a friendly "competition" about which telescope makes the "best" images! The ANTU-team has worked with the FORS multi-mode instrument , their colleagues at KUEYEN use the VLT Test Camera for the ongoing tests of this new telescope. While the first is a highly developed astronomical instrument with a large-field CCD imager (6.8 x 6.8 arcmin 2 in the normal mode; 3.4 x 3.4 arcmin 2 in the high-resolution mode), the other is a less complex CCD camera with a smaller field (1.5 x 1.5 arcmin 2 ), suited to verify the optical performance of the telescope. As these images demonstrate, the performance of the second VLT Unit Telescope is steadily improving and it may not be too long before its optical quality will approach that of the first. First KUEYEN photos of stars and galaxies We present here some of the first astronomical images, taken with the second telescope, KUEYEN, in late March and early April 1999. They reflect the current status of the optical, electronic and mechanical systems, still in the process of being tuned. As expected, the experience gained from ANTU last year has turned out to be invaluable and has allowed good progress during this extremely delicate process. ESO PR Photo 19a/99 ESO PR Photo 19a/99 [Preview - JPEG: 400 x 433 pix - 160k] [Normal - JPEG: 800 x 866 pix - 457k] [High

  19. New Vistas Open with MIDI at the VLT Interferometer

    Science.gov (United States)

    2002-12-01

    "First Fringes" in Mid-Infrared Spectral Region with Two Giant Telescopes Summary Following several weeks of around-the-clock work, a team of astronomers and engineers from Germany, the Netherlands, France and ESO [2] has successfully performed the first observations with the MID-Infrared interferometric instrument (MIDI), a new, extremely powerful instrument just installed in the underground laboratory of the VLT Interferometer (VLTI) at the Paranal Observatory (Chile). In the early morning of December 15, 2002, two of the 8.2 m VLT unit telescopes (ANTU and MELIPAL) were pointed towards the southern star eta Carinae and the two light beams were directed via the complex intervening optics system towards MIDI. After a few hours of tuning and optimization, strong and stable interferometric fringes were obtained, indicating that all VLTI components - from telescopes to the new instrument - were working together perfectly. Two more stars were observed before sunrise, further proving the stability of the entire system. The first observations with MIDI mark one more important step towards full and regular operation of the VLT Interferometer [3] . They are a result of five years of determined efforts within a concerted technology project, based on a close collaboration between ESO and several European research institutes (see below). Now opening great research vistas, they also represent several "firsts" in observational astrophysics, together amounting to a real breakthrough in the field of astronomical interferometry . New views at mid-infrared wavelengths : MIDI is sensitive to light of a wavelength near 10 µm, i.e., in the mid-infrared spectral region ("thermal infrared"). This provides rich opportunities to study a wide range of otherwise inaccessible, crucial astrophysical phenomena, e.g., the formation of planets in dusty disks around newborn stars and the innermost regions around black holes. However, it is a great technical challenge to perform mid

  20. The VLT Adaptive Optics Facility Project: Telescope Systems

    Science.gov (United States)

    Arsenault, Robin; Hubin, Norbert; Stroebele, Stefan; Fedrigo, Enrico; Oberti, Sylvain; Kissler-Patig, Markus; Bacon, Roland; McDermid, Richard; Bonaccini-Calia, Domenico; Biasi, Roberto; Gallieni, Daniele; Riccardi, Armando; Donaldson, Rob; Lelouarn, Miska; Hackenberg, Wolfgang; Conzelman, Ralf; Delabre, Bernard; Stuik, Remko; Paufique, Jerome; Kasper, Markus; Vernet, Elise; Downing, Mark; Esposito, Simone; Duchateau, Michel; Franx, Marijn; Myers, Richard; Goodsell, Steven

    2006-03-01

    The Adaptive Optics Facility is a project to convert UT4 into a specialised Adaptive Telescope. The present secondary mirror (M2) will be replaced by a new M2-Unit hosting a 1170-actuator deformable mirror. The three focal stations will be equipped with instruments adapted to the new capability of this UT. Two instruments have been identified for the two Nasmyth foci: Hawk-I with its AO module GRAAL allowing a Ground Layer Adaptive Optics correction and MUSE with GALACSI for GLAO correction and Laser Tomography Adaptive Optics correction. A future instrument still needs to be defined for the Cassegrain focus. Several guide stars are required for the type of adaptive corrections needed and a Four Laser Guide Star Facility (4LGSF) is being developed in the scope of the AO Facility. Convex mirrors like the VLT M2 represent a major challenge for testing and a substantial effort is dedicated to this. ASSIST, is a test bench that will allow testing of the Deformable Secondary Mirror and both instruments with simulated turbulence. This article focusses on the telescope systems (Adaptive Secondary, Four Laser Guide Star Facility, RTC platform and ASSIST Test Bench). The following article describes the AO Modules GALACSI and GRAAL.

  1. VLT polarimetry observations of PSR B0656+14

    CERN Document Server

    Mignani, R P; Shearer, A; Testa, V; Sowikowska, A; Rudak, B; Krzeszowki, K; Kanbach, G

    2015-01-01

    Optical polarisation measurements are key tests for different models of the pulsar magnetosphere. Furthermore, comparing the relative orientation of the phase-averaged linear polarisation direction and the pulsar proper motion vector may unveil a peculiar alignment, clearly seen in the Crab pulsar. Our goal is to obtain the first measurement of the phase-averaged optical linear polarisation of the fifth brightest optical pulsar, PSR\\, B0656+14, which has also a precisely measured proper motion, and verify a possible alignment between the polarisation direction and the proper motion vector. We carried out observations with the Very Large Telescope (VLT) to measure the phase-averaged optical polarisation degree (P.D.) and position angle (P.A.) of PSR B0656+14. We measured a P.D. of $11.9\\%\\pm5.5\\%$ and a P.A. of $125.8\\degr\\pm13.2\\degr$, measured East of North. Albeit of marginal significance, this is the first measurement of the phase-averaged optical P. D. for this pulsar. Moreover, we found that the P.A. of ...

  2. Astrometric precision of observations at VLT/FORS2

    CERN Document Server

    Lazorenko, P F

    2005-01-01

    In this paper we test the astrometric precision of VLT/FORS2 observations using a serie of CCD frames taken in Galactic bulge area. A special reduction method based on symmetrization of reference fields was used to reduce the atmospheric image motion. Positional precision of unsaturated R=16 mag star images at 17 sec exposure and 0.55 arcsec seeing was found to be equal to 300 microarcsec. The total error of observations was decomposed into components. It was shown that astrometric error depends largely on the photon centroiding error of the target (250 microarcsec for 16 mag stars) while the image motion is much less (110 microarcsec). At galactic latitudes to about 20 degrees, precision for a serie of frames with a 10 min total exposure is estimated to be 30-50 microarcsec for 14-16 mag stars providing the images are not overexposed and the filter R "special" is used. Error estimates for fields with smaller sky star density are given. We conclude that astrometric observations with large telescopes, under op...

  3. Sharpest Ever VLT Images at NAOS-CONICA "First Light"

    Science.gov (United States)

    2001-12-01

    Very Promising Start-Up of New Adaptive Optics Instrument at Paranal Summary A team of astronomers and engineers from French and German research institutes and ESO at the Paranal Observatory is celebrating the successful accomplishment of "First Light" for the NAOS-CONICA Adaptive Optics facility . With this event, another important milestone for the Very Large Telescope (VLT) project has been passed. Normally, the achievable image sharpness of a ground-based telescope is limited by the effect of atmospheric turbulence. However, with the Adaptive Optics (AO) technique, this drawback can be overcome and the telescope produces images that are at the theoretical limit, i.e., as sharp as if it were in space . Adaptive Optics works by means of a computer-controlled, flexible mirror that counteracts the image distortion induced by atmospheric turbulence in real time. The larger the main mirror of the telescope is, and the shorter the wavelength of the observed light, the sharper will be the images recorded. During a preceding four-week period of hard and concentrated work, the expert team assembled and installed this major astronomical instrument at the 8.2-m VLT YEPUN Unit Telescope (UT4). On November 25, 2001, following careful adjustments of this complex apparatus, a steady stream of photons from a southern star bounced off the computer-controlled deformable mirror inside NAOS and proceeded to form in CONICA the sharpest image produced so far by one of the VLT telescopes. With a core angular diameter of only 0.07 arcsec, this image is near the theoretical limit possible for a telescope of this size and at the infrared wavelength used for this demonstration (the K-band at 2.2 µm). Subsequent tests reached the spectacular performance of 0.04 arcsec in the J-band (wavelength 1.2 µm). "I am proud of this impressive achievement", says ESO Director General Catherine Cesarsky. "It shows the true potential of European science and technology and it provides a fine

  4. MASSIVE STARS: FROM THE VLT TO THE ELT

    Directory of Open Access Journals (Sweden)

    Chris Evans

    2008-01-01

    Full Text Available Nuestro conocimiento de las estrellas masivas ha aumentado significativamente en los últimos 30 años gracias a las nuevas instalaciones y tecnologías. En esta contribución presento un gran survey de estrellas masivas que se ha realizado recientemente mediante el uso de VLT-FLAMES, mostrando los campos observados y remarcando la fracción de estrellas binarias que se ha encontrado. Estos datos se han utilizado para la primera comprobación empírica de la dependencia de la intensidad de los vientos estelares con la metalicidad, encontrándose un buen acuerdo con la teoría un resultado de gran importancia para los modelos de evolución estelar, que se utilizan para la interpretación de cúmulos lejanos, starburst y galaxias con formación estelar. Dando un paso más, comentaré como en la actualidad se están dedicando grandes esfuerzos al avance de los planes de actuación y desarrollo de los Telescopios de Gran Tamaño, que serán una realidad en un futuro próximo; este hecho nos ofrecerá una posibilidad más que interesante para obtener observaciones con resolución espacial de estrellas masivas más allá del Grupo Local.

  5. VLT spectroscopy of XTE J2123-058 during quiescence

    CERN Document Server

    Casares, J; Shahbaz, T; Zurita, C; Charles, P A

    2001-01-01

    We present VLT low resolution spectroscopy of the neutron star X-ray transient XTE J2123-058 during its quiescent state. Our data reveal the presence of a K7V companion which contributes 77 % to the total flux at 6300 A and orbits the neutron star at K_2 = 287 +/- 12 km/s. Contrary to other soft X-ray transients (SXTs), the Halpha emission is almost exactly in antiphase with the velocity curve of the optical companion. Using the light-center technique we obtain K_1 = 140 +/- 27 km/s and hence q=K_1/K_2=M_2/M_1= 0.49 +/- 0.10. This, combined with a previous determination of the inclination angle (i=73 +/- 4) yields M_1 = 1.55 +/- 0.31 Msun and M_2 = 0.76 +/- 0.22 Msun. M_2 agrees well with the observed spectral type. Doppler tomography of the Halpha emission shows a non-symmetric accretion disc distribution mimicking that seen in SW Sex stars. Although we find a large systemic velocity of -110 +/- 8 km/s this value is consistent with the galactic rotation velocity at the position of J2123-058, and hence a halo...

  6. The VLT Measures the Shape of a Type Ia Supernova

    Science.gov (United States)

    2003-08-01

    First Polarimetric Detection of Explosion Asymmetry has Cosmological Implications Summary An international team of astronomers [2] has performed new and very detailed observations of a supernova in a distant galaxy with the ESO Very Large Telescope (VLT) at the Paranal Observatory (Chile). They show for the first time that a particular type of supernova, caused by the explosion of a "white dwarf", a dense star with a mass around that of the Sun, is asymmetric during the initial phases of expansion . The significance of this observation is much larger than may seem at a first glance . This particular kind of supernova, designated "Type Ia", plays a very important role in the current attempts to map the Universe. It has for long been assumed that Type Ia supernovae all have the same intrinsic brightness , earning them a nickname as "standard candles". If so, differences in the observed brightness between individual supernovae of this type simply reflect their different distances. This, and the fact that the peak brightness of these supernovae rivals that of their parent galaxy, has allowed to measure distances of even very remote galaxies . Some apparent discrepancies that were recently found have led to the discovery of cosmic acceleration . However, this first clearcut observation of explosion asymmetry in a Type Ia supernova means that the exact brightness of such an object will depend on the angle from which it is seen. Since this angle is unknown for any particular supernova, this obviously introduces an amount of uncertainty into this kind of basic distance measurements in the Universe which must be taken into account in the future. Fortunately, the VLT data also show that if you wait a little - which in observational terms makes it possible to look deeper into the expanding fireball - then it becomes more spherical. Distance determinations of supernovae that are performed at this later stage will therefore be more accurate. PR Photo 24a/03 : Spiral galaxy NGC

  7. Uveitis due to anaplasmosis in a newborn Holstein calf Uveíte por anaplasmose em bezerro da raça Holandesa

    Directory of Open Access Journals (Sweden)

    J.L. Laus

    2006-12-01

    Full Text Available Relata-se o caso de um bovino com, aproximadamente, seis horas de vida, apresentando histórico de febre, apatia, inapetência e desconforto ocular. No exame oftálmico rotineiro, encontraram-se valores do teste da lágrima de Schirmer aumentados, diminuição da pressão intra-ocular, hemorragia conjuntival, uveíte anterior, edema corneal e injeção ciliar em ambos os olhos. Coletou-se amostra de sangue para realização de esfregaço sangüíneo, hemograma e bioquímica sérica. No esfregaço visibilizaram-se corpúsculos de Anaplasma marginale em hemácias parasitadas. Quanto à bioquímica sérica, não foram observadas alterações. Os mesmos exames foram realizados na mãe do animal tendo como resultado a positividade para A. marginale. Para o controle da uveíte foi utilizada uma única aplicação de 0,5ml de betametasona a 5%, por via subconjuntival, em cada um dos olhos. Para o tratamento da anaplasmose, seguiu-se o protocolo a base de 10mg/kg de oxitetraciclina, por via intramuscular profunda, a cada 12 horas. Diante os achados oftálmicos e a presença de corpúsculos de A. marginale em hemácias parasitadas, contatou-se, ser um caso de uveíte crônica secundaria a doença sistêmica, factível com Anaplasmose.

  8. Utilidad del Análisis de las Muestras Intraoculares en el Diagnóstico de las Uveítis

    OpenAIRE

    2016-01-01

    OBJETIVO: Mientras que las uveítis o inflamaciones intraoculares de origen infeccioso suponen generalmente la curación de la enfermedad, las de origen no-infeccioso conllevan tratamientos médicos crónicos y quirúrgicos recurrentes, con la consiguiente morbilidad potencial y costes económicos importantes. Este estudio realiza un análisis de los beneficios, tanto diagnósticos como económicos, de la realización de pruebas de laboratorio en muestras oculares durante el diagnóstico ...

  9. Características clínicas y diagnóstico etiológico de las uveítis virales

    Directory of Open Access Journals (Sweden)

    Adrianne Mayuli Suñet Álvarez

    Full Text Available Objetivo: determinar las características clínicas y epidemiológicas de las uveítis virales según su etiología. Métodos: se realizó un estudio observacional y descriptivo transversal, que determinó el diagnóstico clínico y etiológico, según la reacción en cadena de polimerasa (PCR de 10 ojos de pacientes atendidos en la consulta de uveítis, en el Instituto Cubano de Oftalmología «Ramón Pando Ferrer», de mayo a noviembre del 2010. Se utilizó una muestra de fluidos intraoculares tomada a los pacientes. Las variables analizadas fueron: edad, sexo, color de piel, antecedentes personales generales u oculares, clasificación anatómica y patológica de la uveítis, curso evolutivo, bilateralidad, agudeza visual y presión intraocular iniciales y finales respectivamente, hallazgos al fondo de ojo y resultados de la PCR. La información fue procesada y los resultados expuestos en tablas. Resultados: la edad promedio de los pacientes estudiados fue de 34,5 años, que presentaron en su mayoría episodios de uveítis anteriores unilaterales. La agudeza visual mejor corregida final mejoró con respecto a la inicial en el grupo de estudio, aunque la presión intraocular se mantuvo elevada sin lograr controlarla. El virus más hallado fue el Herpes simple. Conclusiones: los virus son responsables de producir inflamaciones oculares de presentación variada, lo que en ocasiones retrasa el diagnóstico, empeorando el pronóstico visual. En estos casos el método de PCR ha demostrado ser una herramienta útil para establecer el diagnóstico etiológico.

  10. The Great Observatories Origins Deep Survey - VLT/FORS2 Spectroscopy in the GOODS-South Field

    CERN Document Server

    Vanzella, E; Dickinson, M; Kuntschner, H; Moustakas, L A; Nonino, M; Rosati, P; Stern, D; Césarsky, C J; Ettori, S; Ferguson, H C; Fosbury, R A E; Giavalisco, M; Haase, J; Renzini, A; Rettura, A; Serra, P

    2004-01-01

    We present the first results of the ESO/GOODS program of spectroscopy of faint galaxies in the Chandra Deep Field South (CDF-S). 399 spectra of 303 unique targets have been obtained in service mode with the FORS2 spectrograph at the ESO/VLT, providing 234 redshift determinations (the median of the redshift distribution is at 1.04). The typical redshift uncertainty is estimated to be sig(z) ~ 0.001. Galaxies have been color selected in a way that the resulting redshift distribution typically spans from z=0.5 to 2. The reduced spectra and the derived redshifts are released to the community through the ESO web page http://www.eso.org/science/goods/ Large scale structure is clearly detected at z ~ 0.67, 0.73, 1.10 and 1.61. Three Lyman-break galaxies have also been included as targets and are confirmed to have redshifts z=4.800, 4.882 and 5.828. In a few cases, we observe clear [OII]3727 rotation curves, even at the relatively low resolution (R = 860) of the present observations. Assuming that the observed veloci...

  11. Inequality spectra

    Science.gov (United States)

    Eliazar, Iddo

    2017-03-01

    Inequality indices are widely applied in economics and in the social sciences as quantitative measures of the socioeconomic inequality of human societies. The application of inequality indices extends to size-distributions at large, where these indices can be used as general gauges of statistical heterogeneity. Moreover, as inequality indices are plentiful, arrays of such indices facilitate high-detail quantification of statistical heterogeneity. In this paper we elevate from arrays of inequality indices to inequality spectra: continuums of inequality indices that are parameterized by a single control parameter. We present a general methodology of constructing Lorenz-based inequality spectra, apply the general methodology to establish four sets of inequality spectra, investigate the properties of these sets, and show how these sets generalize known inequality gauges such as: the Gini index, the extended Gini index, the Rényi index, and hill curves.

  12. The VLT Unravels the Nature of the Fastest Binary Star

    Science.gov (United States)

    2002-03-01

    Two Hot White Dwarfs Perform a Tight Dance Summary Observations with ESO's Very Large Telescope (VLT) in Chile and the Italian Telescopio Nazionale Galileo (TNG) on the Canary Islands during the past two years have enabled an international group of astronomers [1] to unravel the true nature of an exceptional binary stellar system. This system, designated RX J0806.3+1527 , was first discovered as an X-ray source of variable brightness - once every five minutes, it "switches off" for a short moment. The new observations have shown beyond doubt that this period reflects the orbital motion of two "white dwarf" stars that revolve around each other at a distance of only 80,000 km . Each of the stars is about as large as the Earth and this is the shortest orbital period known for any binary stellar system. The VLT spectrum displays lines of ionized helium, indicating that the presence of an exceedingly hot area on one of the stars - a "hot spot" with a temperature of approx. 250,000 degrees. The system is currently in a rarely seen, transitory evolutionary state . PR Photo 10a/02 : U- and R-band images of RX J0806.3+1527. PR Photo 10b/02 : Spectrum of RX J0806.3+1527 An amazing stellar binary system ESO PR Photo 10a/02 ESO PR Photo 10a/02 [Preview - JPEG: 800 x 400 pix - 440k] [Normal - JPEG: 1600 x 800 pix - 1.1M] Caption : PR Photo 10a/02 shows U and R filter images of the sky field around RX J0806.3+1527 (at centre of circle), obtained with the FORS2 multi-mode instrument on VLT KUEYEN. The object is brightest at the shorter wavelength (U-band) - reflecting its very high temperature. Technical information about the photo is available below. One year is the time it takes the Earth to move once around the Sun, our central star. This may seem quite fast when measured on the scale of the Universe, but this is a snail's motion compared to the the speed of two recently discovered stars. They revolve around each other 100,000 times faster; one full revolution takes only 321

  13. Uveitis as first manifestation of probably Crohn's disease Uveíte como primeira manifestação de provável doença de Crohn

    Directory of Open Access Journals (Sweden)

    Ieda Maria Alexandre Barreira

    2012-12-01

    Full Text Available Extraintestinal manifestations of Crohn's disease are common. Although ocular complications of Crohn's disease are infrequent, most ocular manifestations include iritis, uveitis, episcleritis, scleritis and conjuntivitis. We report a patient who developed uveitis two years before diagnose of Crohn's disease.Manifestações extraintestinais da doença de Crohn são comuns. As manifestações oculares são infrequentes e caracterizam-se em sua maioria por irite, uveíte, episclerite, esclerite e conjuntivite. Relatamos o caso de uma paciente que desenvolveu uveíte dois anos antes de firmado o diagnóstico de doenca de Crohn.

  14. Line-by-line analysis of Neptune's near-IR spectrum observed with Gemini/NIFS and VLT/CRIRES

    Science.gov (United States)

    Irwin, P. G. J.; Lellouch, E.; de Bergh, C.; Courtin, R.; Bézard, B.; Fletcher, L. N.; Orton, G. S.; Teanby, N. A.; Calcutt, S. B.; Tice, D.; Hurley, J.; Davis, G. R.

    2014-01-01

    New line data describing the absorption of CH4 and CH3D from 1.26 to 1.71 μm (WKMC-80K, Campargue, A., Wang, L., Mondelain, D., Kassi, S., Bézard, B., Lellouch, E., Coustenis, A., de Bergh, C., Hirtzig, M., Drossart, P. [2012]. Icarus 219, 110-128) have been applied to the analysis of Gemini-N/NIFS observations of Neptune made in 2009 and VLT/CRIRES observations made in 2010. The new line data are found to greatly improve the fit to the observed spectra and present a considerable advance over previous methane datasets. The improved fits lead to an empirically derived wavelength-dependent correction to the scattering properties of the main observable cloud deck at 2-3 bars that is very similar to the correction determined for Uranus' lower cloud using the same line dataset by Irwin et al. (Irwin, P.G.J., de Bergh, C., Courtin, R., Bézard, B., Teanby, N.A., Davis, G.R., Fletcher, L.N., Orton, G.S., Calcutt, S.B., Tice, D., Hurley, J. [2012]. Icarus 220, 369-382). By varying the abundance of CH3D in our simulations, analysis of the Gemini/NIFS observations leads to a new determination of the CH3D/CH4 ratio for Neptune of 3.0-0.9+1.0×10-4, which is smaller than previous determinations, but is identical (to within error) with the CH3D/CH4 ratio of 2.9-0.5+0.9×10-4 derived by a similar analysis of Gemini/NIFS observations of Uranus made in the same year. Thus it appears that the atmospheres of Uranus and Neptune have an almost identical D/H ratio, which suggests that the icy planetisimals forming these planets came from the same source reservoir, or a reservoir that was well-mixed at the locations of ice giant formation, assuming complete mixing between the atmosphere and interior of both these planets. VLT/CRIRES observations of Neptune have also been analysed with the WKMC-80K methane line database, yielding very good fits, with little evidence for missing absorption features. The CRIRES spectra indicate that the mole fraction of CO at the 2-3 bar level must be

  15. First light of the VLT planet finder SPHERE - II. The physical properties and the architecture of the young systems PZ Tel and HD 1160 revisited

    CERN Document Server

    Maire, A -L; Ginski, C; Vigan, A; Messina, S; Mesa, D; Galicher, R; Gratton, R; Desidera, S; Kopytova, T G; Millward, M; Thalmann, C; Claudi, R U; Ehrenreich, D; Zurlo, A; Chauvin, G; Antichi, J>; Baruffolo, A; Bazzon, A; Beuzit, J -L; Blanchard, P; Boccaletti, A; de Boer, J; Carle, M; Cascone, E; Costille, A; De Caprio, V; Delboulbe, A; Dohlen, K; Dominik, C; Feldt, M; Fusco, T; Girard, J H; Giro, E; Gisler, D; Gluck, L; Gry, C; Henning, T; Hubin, N; Hugot, E; Jaquet, M; Kasper, M; Lagrange, A -M; Langlois, M; Mignant, D Le; Llored, M; Madec, F; Martinez, P; Mawet, D; Milli, J; Moeller-Nilsson, O; Mouillet, D; Moulin, T; Moutou, C; Origne, A; Pavlov, A; Petit, C; Pragt, J; Puget, P; Ramos, J; Rochat, S; Roelfsema, R; Salasnich, B; Sauvage, J -F; Schmid, H M; Turatto, M; Udry, S; Vakili, F; Wahhaj, Z; Weber, L; Wildi, F

    2015-01-01

    [Abridged] Context. The young systems PZ Tel and HD 1160, hosting known low-mass companions, were observed during the commissioning of the new planet finder SPHERE with several imaging and spectroscopic modes. Aims. We aim to refine the physical properties and architecture of both systems. Methods. We use SPHERE commissioning data and REM observations, as well as literature and unpublished data from VLT/SINFONI, VLT/NaCo, Gemini/NICI, and Keck/NIRC2. Results. We derive new photometry and confirm the nearly daily photometric variability of PZ Tel A. Using literature data spanning 38 yr, we show that the star also exhibits a long-term variability trend. The 0.63-3.8 mic SED of PZ Tel B allows us to revise its properties: spectral type M7+/-1, Teff=2700+/-100 K, log(g)0.66) of PZ Tel B. For e4 MJ) outside 0.5" for the PZ Tel system. We also show that K1-K2 color can be used with YJH low-resolution spectra to identify young L-type companions, provided high photometric accuracy (<0.05 mag) is achieved. Conclusi...

  16. Automatic abundance analysis of high resolution spectra

    CERN Document Server

    Bonifacio, P; Bonifacio, Piercarlo; Caffau, Elisabetta

    2003-01-01

    We describe an automatic procedure for determining abundances from high resolution spectra. Such procedures are becoming increasingly important as large amounts of data are delivered from 8m telescopes and their high-multiplexing fiber facilities, such as FLAMES on ESO-VLT. The present procedure is specifically targeted for the analysis of spectra of giants in the Sgr dSph; however, the procedure may be, in principle, tailored to analyse stars of any type. Emphasis is placed on the algorithms and on the stability of the method; the external accuracy rests, ultimately, on the reliability of the theoretical models (model-atmospheres, synthetic spectra) used to interpret the data. Comparison of the results of the procedure with the results of a traditional analysis for 12 Sgr giants shows that abundances accurate at the level of 0.2 dex, comparable with that of traditional analysis of the same spectra, may be derived in a fast and efficient way. Such automatic procedures are not meant to replace the traditional ...

  17. Efeitos da injeção subtenoniana posterior de corticóide em pacientes com uveíte

    Directory of Open Access Journals (Sweden)

    Finamor Luciana Peixoto

    2003-01-01

    Full Text Available OBJETIVO: Determinar os efeitos da injeção subtenoniana posterior de corticóide (ISPC sobre a pressão intra-ocular (Po e acuidade visual em uma série de pacientes com uveíte. MÉTODOS: Estudo prospectivo de 18 pacientes que foram submetidos à injeção subtenoniana posterior de acetato de triancinolona (Kenalog® 40 mg - 9 pacientes, 14 injeções ou acetato de metilprednisolona (Depomedrol® 40mg - 9 pacientes, 15 injeções para tratamento de inflamação intra-ocular crônica e/ou edema macular cistóide. RESULTADOS: A acuidade visual final melhorou em 92% dos pacientes após a primeira injeção periocular de corticóide. Cinqüenta por cento melhoraram 1 linha e 42% melhoraram pelo menos 3 linhas, sendo que o tempo médio para a melhora foi de 3 semanas. Aumento da pressão intra-ocular ocorreu em 44 % dos pacientes (8 pacientes com média de 31 mmHg, variando de 21 a 38 mmHg. O aumento da pressão intra-ocular foi mais freqüente nos pacientes jovens e nos que receberam Kenalog®, com início, em média, após 2,5 semanas. CONCLUSÃO: Ainjeção subtenoniana de corticóide é uma forma de tratamento eficaz para a baixa acuidade visual secundária a alguns tipos de uveíte, como uveíte intermediária, doença de Behçet, síndrome de Vogt-Koyanagi-Harada, vasculite retiniana e artrite reumatóide. Porém, pode induzir aumento da pressão intra-ocular em alguns pacientes, especialmente em crianças e jovens.

  18. Evaluación farmacoterapéutica y evolutiva de uveítis crónicas y recurrentes no infecciosas

    Directory of Open Access Journals (Sweden)

    Mireya Benítez Cartaya

    Full Text Available Objetivos: evaluar el tratamiento farmacológico e identificar los factores pronósticos en una evolución clínica desfavorable con uveítis crónicas y recurrentes no infecciosas, en el Instituto Cubano Oftalmología "Ramón Pando Ferrer" durante el período 2012-2013. Métodos: se realizó un estudio de utilización de medicamentos. Se efectuó un diseño de cohorte retrospectivo evaluativo y un estudio transversal analítico de factores pronósticos. Fueron evaluados 116 pacientes. Las variables utilizadas correspondieron a la evaluación farmacoterapéutica: selección del medicamento, pauta de administración y causas de incumplimiento terapéutico. Para la evolución clínica desfavorable se analizaron variables sociodemográficas y clínicas. Se calcularon frecuencias absolutas y relativas. Se realizó un análisis univariado. Las variables significativas a la evolución se incluyeron en el modelo de regresión logística múltiple. Resultados: no existieron errores en la prescripción en el 100 % de los evaluados. El 15,5 % de los pacientes no cumplieron con el tratamiento prescrito; 83,3 % se relacionó con la presencia de reacciones adversas y 33,3 % con la falta de disponibilidad. El 57 % presentó efectos adversos por corticoesteroides y el 39 % por inmunosupresores. El curso clínico crónico y la localización resultaron factores influyentes en una evolución desfavorable. Conclusiones: la evaluación farmacoterapéutica en el caso de las uveítis crónicas es adecuada. No existen errores en la prescripción. Las causas más frecuentes de incumplimiento terapéutico son la suspensión del tratamiento por efectos adversos, la falta de disponibilidad de inmunosupresores y la alternativa biológica. El curso clínico crónico y la localización de las uveítis pueden considerarse como un factor pronóstico en la evolución desfavorable de esta enfermedad.

  19. zCOSMOS : A large VLT/VIMOS redshift survey covering 0

    NARCIS (Netherlands)

    Lilly, S. J.; Le Fevre, O.; Renzini, A.; Zamorani, G.; Scodeggio, M.; Contini, T.; Carollo, C. M.; Hasinger, G.; Kneib, J.-P.; Iovino, A.; Le Brun, V.; Maier, C.; Mainieri, V.; Mignoli, M.; Silverman, J.; Tasca, L. A. M.; Bolzonella, M.; Bongiorno, A.; Bottini, D.; Capak, P.; Caputi, K.; Cimatti, A.; Cucciati, O.; Daddi, E.; Feldmann, R.; Franzetti, P.; Garilli, B.; Guzzo, L.; Ilbert, O.; Kampczyk, P.; Kovac, K.; Lamareille, F.; Leauthaud, A.; Le Borgne, J.-F.; McCracken, H. J.; Marinoni, C.; Pello, R.; Ricciardelli, E.; Scarlata, C.; Vergani, D.; Sanders, D. B.; Schinnerer, E.; Scoville, N.; Taniguchi, Y.; Arnouts, S.; Aussel, H.; Bardelli, S.; Brusa, M.; Cappi, A.; Ciliegi, P.; Finoguenov, A.; Foucaud, S.; Franceschini, R.; Halliday, C.; Impey, C.; Knobel, C.; Koekemoer, A.; Kurk, J.; Maccagni, D.; Maddox, S.; Marano, B.; Marconi, G.; Meneux, B.; Mobasher, B.; Moreau, C.; Peacock, J. A.; Porciani, C.; Pozzetti, L.; Scaramella, R.; Schiminovich, D.; Shopbell, P.; Smail, I.; Thompson, D.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Zucca, E.

    2007-01-01

    zCOSMOS is a large-redshift survey that is being undertaken in the COSMOS field using 600 hr of observation with the VIMOS spectrograph on the 8mVLT. The survey is designed to characterize the environments of COSMOS galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cos

  20. Motion control solution for new PLC-based standard development platform for VLT instrument control systems

    Science.gov (United States)

    Popovic, D.; Brast, R.; Di Lieto, N.; Kiekebusch, M.; Knudstrup, J.; Lucuix, C.

    2014-07-01

    More than a decade ago, due to obsolescence issues, ESO initiated the design and implementation of a custom-made CANbus based motion controller (CAN-RMC) to provide, together with a tailor-made software library (motor library), the motion control capabilities for the VME platform needed for the second generation VLT/VLTI instruments. The CAN-RMC controller has been successfully used in a number of VLT instruments but it has high production costs compared to the commercial off-the-shelf (COTS) industrial solutions available on the market today. In the scope of the selection of a new PLC-based platform for the VLT instrument control systems, ESO has evaluated motion control solutions from the company Beckhoff. This paper presents the investigation, implementation and testing of the PLC/TwinCAT/EtherCAT motion controllers for DC and stepper motors and their adaptation and integration into the VLT instrumentation framework. It reports functional and performance test results for the most typical use cases of astronomical instruments like initialization sequences, tracking, switch position detections, backslash compensation, brake handling, etc. In addition, it gives an overview of the main features of TwinCAT NC/PTP, PLCopen MC, EtherCAT motion control terminals and the engineering tools like TwinCAT Scope that are integrated into the development environment and simplify software development, testing and commissioning of motorized instrument functions.

  1. The Cepheid Distance to NGC 5236 (M 83) with the VLT

    NARCIS (Netherlands)

    Thim, F.; Tammann, G. A.; Saha, A.; Dolphin, A.; Sandage, A.; Tolstoy, E.; Labhardt, L.

    2003-01-01

    Published in: Astrophys. J. 590 (2003) 256-270 citations recorded in [Science Citation Index] Abstract: Cepheids have been observed in NGC 5236 (M 83) using the ANTU (UT1) 8.2 meter telescope of the ESO VLT with FORS1. Observations over 34 epochs in V and I have been made between January 2000 and Ju

  2. OmegaCAM: the 16k × 16k Survey Camera for the VLT Survey Telescope

    NARCIS (Netherlands)

    Deul, Erik; Kuijken, Konrad; Valentijn, Edwin A.; Tyson, J. Anthony; Wolff, Sidney

    2002-01-01

    OmegaCAM, a 16k×16k-pixel wide field optical camera, and the VLT Survey Telescope (VST) that is to host it, will constitute a major sky surveying machine that becomes operational in 2004 at ESO"s Paranal Observatory. It maps one square degree of sky with 0.21 arcsec sized pixels. Both individual pro

  3. The VLT LBG Redshift Survey - I. Clustering and dynamics of ≈1000 galaxies at z≈ 3

    NARCIS (Netherlands)

    Bielby, R. M.; Shanks, T.; Weilbacher, P. M.; Infante, L.; Crighton, N. H. M.; Bornancini, C.; Bouché, N.; Héraudeau, P.; Lambas, D. G.; Lowenthal, J.; Minniti, D.; Padilla, N.; Petitjean, P.; Theuns, T.

    2011-01-01

    We present the initial imaging and spectroscopic data acquired as part of the Very Large Telescope (VLT) VIMOS Lyman-break galaxy Survey. UBR (or UBVI) imaging covers five ≈36 × 36 arcmin2 fields centred on bright z > 3 quasi-stellar objects (QSOs), allowing ≈21 000 2

  4. MOONS: a multi-object optical and near-infrared spectrograph for the VLT

    NARCIS (Netherlands)

    Cirasuolo, M.; Afonso, J.; Bender, R.; Bonifacio, P.; Evans, C.; Kaper, L.; Oliva, Ernesto; Vanzi, Leonardo; Abreu, Manuel; Atad-Ettedgui, Eli; Babusiaux, Carine; Bauer, Franz E.; Best, Philip; Bezawada, Naidu; Bryson, Ian R.; Cabral, Alexandre; Caputi, Karina; Centrone, Mauro; Chemla, Fanny; Cimatti, Andrea; Cioni, Maria-Rosa; Clementini, Gisella; Coelho, João.; Daddi, Emanuele; Dunlop, James S.; Feltzing, Sofia; Ferguson, Annette; Flores, Hector; Fontana, Adriano; Fynbo, Johan; Garilli, Bianca; Glauser, Adrian M.; Guinouard, Isabelle; Hammer, Jean-François; Hastings, Peter R.; Hess, Hans-Joachim; Ivison, Rob J.; Jagourel, Pascal; Jarvis, Matt; Kauffman, G.; Lawrence, A.; Lee, D.; Li Causi, G.; Lilly, S.; Lorenzetti, D.; Maiolino, R.; Mannucci, F.; McLure, R.; Minniti, D.; Montgomery, D.; Muschielok, B.; Nandra, K.; Navarro, R.; Norberg, P.; Origlia, L.; Padilla, N.; Peacock, J.; Pedicini, F.; Pentericci, L.; Pragt, J.; Puech, M.; Randich, S.; Renzini, A.; Ryde, N.; Rodrigues, M.; Royer, F.; Saglia, R.; Sánchez, A.; Schnetler, H.; Sobral, D.; Speziali, R.; Todd, S.; Tolstoy, E.; Torres, M.; Venema, L.; Vitali, F.; Wegner, M.; Wells, M.; Wild, V.; Wright, G.

    2012-01-01

    MOONS is a new conceptual design for a Multi-Object Optical and Near-infrared Spectrograph for the Very Large Telescope (VLT), selected by ESO for a Phase A study. The baseline design consists of ~1000 fibers deployable over a field of view of ~500 square arcmin, the largest patrol field offered by

  5. The VLT-FLAMES Tarantula Survey: I. Introduction and observational overview

    NARCIS (Netherlands)

    Evans, C.J.; Taylor, W.D.; Hénault-Brunet, V.; Sana, H.A.A.; de Koter, A.; Simón-Díaz, S.; Carraro, G.; Bagnoli, T.; Bastian, N.; Bestenlehner, J.M.; Bonanos, A.Z.; Bressert, E.; Brott, I.; Campbell, M.A.; Cantiello, M.; Clark, J.S.; Costa, E.; Crowther, P.A.; de Mink, S.E.; Doran, E.; Dufton, P.L.; Dunstall, P.R.; Friedrich, K.; Garcia, M.; Gieles, M.; Gräfener, G.; Herrero, A.; Howarth, I.D.; Izzard, R.G.; Langer, N.; Lennon, D.J.; Maiz Apellániz, J.; Markova, N.; Najarro, F.; Puls, J.; Ramirez, O.H.; Sabín-Sanjulián, C.; Smartt, S.J.; Stroud, V.E.; van Loon, J.T.; Vink, J.S.; Walborn, N.R.

    2011-01-01

    The VLT-FLAMES Tarantula Survey (VFTS) is an ESO Large Programme that has obtained multi-epoch optical spectroscopy of over 800 massive stars in the 30 Doradus region of the Large Magellanic Cloud (LMC). Here we introduce our scientific motivations and give an overview of the survey targets, includi

  6. The VLT-FLAMES Tarantula Survey. I. Introduction and observational overview

    NARCIS (Netherlands)

    Evans, C.J.; Taylor, W.D.; de Koter, A.; Brott, I.; Walborn, N.R.

    2011-01-01

    The VLT-FLAMES Tarantula Survey (VFTS) is an ESO Large Programme that has obtained multi-epoch optical spectroscopy of over 800 massive stars in the 30 Doradus region of the Large Magellanic Cloud (LMC). Here we introduce our scientific motivations and give an overview of the survey targets, includi

  7. Alcohol affects video lottery terminal (VLT) gambling behaviors and cognitions differently.

    Science.gov (United States)

    Ellery, Michael; Stewart, Sherry H

    2014-03-01

    People frequently combine alcohol use and gambling. However, our understanding of the effects of alcohol on gambling behavior is limited, both in terms of what the effects are and how they occur. The effects of a moderately intoxicating dose of alcohol (i.e., a blood alcohol concentration of .06 g%) on the video lottery terminal (VLT) gambling behaviors and cognitions of community-recruited nonpathological (n = 30) and probable pathological gamblers (n = 30) were compared. Alcohol increased the rate of double up betting (i.e., choosing to play a bonus game, after a winning video poker hand, which involves trying to pick a higher ranked card than the dealer's card from among 5 face down cards) of probable pathological gamblers, but did not influence their irrational beliefs about VLT play. Alcohol maintained the irrational beliefs about VLT play of nonpathological gamblers, but did not influence their gambling behaviors. Results are consistent with a growing body of research finding that gambling cognitions have an equivocal role in explaining actual gambling behaviors. Potential mechanisms for the observed effects are discussed. Applied implications discussed include: educating regular VLT players about the effects of alcohol on irrational gambling cognitions; reconsidering policies and practices that make alcohol available where machine gambling takes place; and targeting even moderate alcohol use in the treatment of gambling problems.

  8. The VLT-FLAMES Tarantula Survey. XXII. Multiplicity properties of the B-type stars

    NARCIS (Netherlands)

    Dunstall, P.R.; Dufton, P.L.; Sana, H.; Evans, C.J.; Howarth, I.D.; Simón-Díaz, S.; de Mink, S.E.; Langer, N.; Maíz Apellániz, J.; Taylor, W.D.

    2015-01-01

    We investigate the multiplicity properties of 408 B-type stars observed in the 30 Doradus region of the Large Magellanic Cloud with multi-epoch spectroscopy from the VLT-FLAMES Tarantula Survey (VFTS). We use a cross-correlation method to estimate relative radial velocities from the helium and metal

  9. Athermal design of the optical tube assemblies for the ESO VLT four laser guidestar facility

    NARCIS (Netherlands)

    Henselmans, R.; Nijkerk, M.D.; Lemmen, M.H.J.; Rijnveld, N.; Kamphues, F.G.

    2011-01-01

    TNO is developing the Optical Tube Asssemblies (OTAs) for the ESO VLT Four Laser Guide Star Facility. The OTAs are Galilean 20x beam expanders, expanding a Ø15 mm input beam to a steerable Ø300 mm output beam with a wavefront quality requirement of 50 nm rms. The allowed defocus under the influence

  10. VIMOS-VLT and Spitzer observations of a radio galaxy at z=2.5

    NARCIS (Netherlands)

    Villar-Martin, M; Sanchez, SF; De Breuck, C; Peletier, R; Vernet, J; Rettura, A; Seymour, N; Humphrey, A; Stern, D; Alighieri, SD; Fosbury, R

    2006-01-01

    We present: (i) a kinematic and morphological study of the giant Ly alpha nebula associated with the radio galaxy MRC 2104-242 (z = 2.49) based on integral field spectroscopic Visible Multiobject Spectrograph (VIMOS) data from the Very Large Telescope (VLT), and (ii) a photometric study of the host

  11. Data Mining for Double Stars on VLT Survey Telescope Image Archive

    Science.gov (United States)

    Curelaru, Lucian

    2017-04-01

    The article presents a set of methods and tools used to identify and measure double stars on already existing images produced by the ESO VLT Survey Telescope in Paranal Chile. A precision analysis and a first set of measurements are included.

  12. The Vimos VLT Deep Survey: Global properties of 20000 galaxies in the I_AB<=22.5 WIDE survey

    CERN Document Server

    Garilli, B; Guzzo, L; MacCagni, D; Le Brun, V; De la Torre, S; Meneux, B; Tresse, L; Franzetti, P; Zamorani, G; Zanichelli, A; Gregorini, L; Vergani, D; Bottini, D; Scaramella, R; Scodeggio, M; Vettolani, G; Adami, C; Arnouts, S; Bardelli, S; Bolzonella, M; Cappi, A; Charlot, S; Ciliegi, P; Contini, T; Foucaud, S; Gavignaud, I; Ilbert, O; Iovino, A; Lamareille, F; McCracken, H J; Marano, B; Marinoni, C; Mazure, A; Merighi, R; Paltani, S; Pellò, R; Pollo, A; Pozzetti, L; Radovich, M; Zucca, E; Blaizot, J; Bongiorno, A; Cucciati, O; Mellier, Y; Moreau, C; Paioro, L

    2008-01-01

    The VVDS-Wide survey has been designed with the general aim of tracing the large-scale distribution of galaxies at z~1 on comoving scales reaching ~100Mpc/h, while providing a good control of cosmic variance over areas as large as a few square degrees. This is achieved by measuring redshifts with VIMOS at the ESO VLT to a limiting magnitude I_AB=22.5, targeting four independent fields with size up to 4 sq.deg. each. The whole survey covers 8.6 sq.deg., here we present the general properties of the current redshift sample. This includes 32734 spectra in the four regions (19977 galaxies, 304 type I AGNs, and 9913 stars), covering a total area of 6.1 sq.deg, with a sampling rate of 22 to 24%. The redshift success rate is above 90% independently of magnitude. It is the currently largest area coverage among redshift surveys reaching z~1. We give the mean N(z) distribution averaged over 6.1 sq.deg. Comparing galaxy densities from the four fields shows that in a redshift bin Deltaz=0.1 at z~1 one still has factor-of...

  13. Integral field spectroscopy of planetary nebulae: mapping the line diagnostics and hydrogen-poor zones with VLT FLAMES

    CERN Document Server

    Tsamis, Y G; Péquignot, D; Barlow, M J; Danziger, I J; Liu, X -W

    2008-01-01

    (Abridged) Results from the first dedicated study of Galactic PNe by means of optical integral field spectroscopy with the VLT FLAMES Argus IFU are presented. Three typical Galactic-disk PNe have been mapped with the 11.5''x7.2'' Argus array: two dimensional spectral maps of NGC 5882, 6153 and 7009 with 297 spatial pixels per target were obtained at sub-arcsec resolutions and 297 spectra per target were obtained in the 396.4-507.8 nm range. Spatially resolved maps of emission lines and of nebular physical properties were produced. The abundances of helium and of doubly ionized carbon and oxygen were derived from optical recombination lines (ORLs), while those of O^2+ were also derived from the collisionally excited lines (CELs). The abundance discrepancy problem was investigated by mapping the ratio of ORL/CEL abundances for O^2+ (the abundance discrepancy factor; ADF) across the face of the PNe. The ADF varies between targets and also with position within the targets attaining values of ~40 in the case of NG...

  14. SINFONI/VLT 3D spectroscopy of massive galaxies: Strong rotational support at z~1.4

    CERN Document Server

    Buitrago, Fernando; Epinat, Benoit; Bedregal, Alejandro G; Grutzbauch, Ruth

    2013-01-01

    There is cumulative evidence showing that, for the most massive galaxies, the fraction of disk-like objects compared to those with spheroidal properties increases with redshift. However, this evidence is thus far based on detailed morphological analyses of these objects which ultimately rests on the shape of their surface brightness profiles. To explore the consistency of this scenario, it is necessary to measure the dynamical status of these galaxies. With this aim we have obtained near-infrared integral field spectra in the H-band for 10 massive galaxies (M_{stellar} >10^{11} h_{70}^-2 M_{Sun}) at z~1.4 with SINFONI at the VLT. Our sample is selected by their stellar mass and EW[OII] > 15\\AA, to secure their kinematic measurements, but without accounting for any morphological or flux criteria a priori. Through this 3D kinematic spectroscopy analysis we find that half (i.e. 50+/-7%) of our galaxies are compatible with being rotationally supported disks, in agreement with previous morphological expectations. ...

  15. The Resolved Structure and Dynamics of an Isolated Dwarf Galaxy: A VLT and Keck Spectroscopic Survey of WLM

    CERN Document Server

    Leaman, Ryan; Brooks, Alyson M; Battaglia, Giuseppina; Cole, Andrew A; Ibata, Rodrigo A; Irwin, Mike J; McConnachie, Alan W; Mendel, J Trevor; Tolstoy, Eline

    2012-01-01

    We present spectroscopic data for 180 red giant branch stars in the isolated dwarf irregular galaxy WLM. Observations of the Calcium II triplet lines in spectra of RGB stars covering the entire galaxy were obtained with FORS2 at the VLT and DEIMOS on Keck II allowing us to derive velocities, metallicities, and ages for the stars. With accompanying photometric and radio data we have measured the structural parameters of the stellar and gaseous populations over the full galaxy. The stellar populations show an intrinsically thick configuration with $0.39 \\leq q_{0} \\leq 0.57$. The stellar rotation in WLM is measured to be $17 \\pm 1$ km s$^{-1}$, however the ratio of rotation to pressure support for the stars is $V/\\sigma \\sim 1$, in contrast to the gas whose ratio is seven times larger. This, along with the structural data and alignment of the kinematic and photometric axes, suggests we are viewing WLM as a highly inclined oblate spheroid. Stellar rotation curves, corrected for asymmetric drift, are used to comp...

  16. VIMOS-VLT Integral Field Kinematics of the Giant Low Surface Brightness Galaxy ESO 323-G064

    CERN Document Server

    Coccato, L; Rubin, V C; D'Odorico, S; McGaugh, S S

    2008-01-01

    Aims:We have studied the bulge and the disk kinematics of the giant low surface brightness galaxy ESO 323-G064 in order to investigate its dynamical properties and the radial mass profile of the dark matter (DM) halo. Methods:We observed the galaxy with integral field spectroscopy (VLT/VIMOS, in IFU configuration), measured the positions of the ionized gas by fitting Gaussian functions to the O[III] and Hbeta emission lines, and fit stellar templates to the galaxy spectra to determine velocity and velocity dispersions. We modeled the stellar kinematics in the bulge with spherical isotropic Jeans models and explored the implications of self consistent and dark matter scenarios for NFW and pseudo isothermal halos. Results:In the bulge-dominated region, r<5", the emission lines show multi-peaked profiles. The disk dominated region of the galaxy, 13"

  17. A VLT/FLAMES STUDY OF THE PECULIAR INTERMEDIATE-AGE LARGE MAGELLANIC CLOUD STAR CLUSTER NGC 1846. I. KINEMATICS

    Energy Technology Data Exchange (ETDEWEB)

    Mackey, A. D.; Da Costa, G. S.; Yong, D. [Research School of Astronomy and Astrophysics, The Australian National University, Mount Stromlo Observatory, via Cotter Road, Weston, ACT 2611 (Australia); Ferguson, A. M. N., E-mail: dougal@mso.anu.edu.au [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom)

    2013-01-01

    In this paper we present high-resolution VLT/FLAMES observations of red giant stars in the massive intermediate-age Large Magellanic Cloud star cluster NGC 1846, which, on the basis of its extended main-sequence turnoff (EMSTO), possesses an internal age spread of Almost-Equal-To 300 Myr. We describe in detail our target selection and data reduction procedures, and construct a sample of 21 stars possessing radial velocities indicating their membership of NGC 1846 at high confidence. We consider high-resolution spectra of the planetary nebula Mo-17, and conclude that this object is also a member of the cluster. Our measured radial velocities allow us to conduct a detailed investigation of the internal kinematics of NGC 1846, the first time this has been done for an EMSTO system. The key result of this work is that the cluster exhibits a significant degree of systemic rotation, of a magnitude comparable to the mean velocity dispersion. Using an extensive suite of Monte Carlo models we demonstrate that, despite our relatively small sample size and the substantial fraction of unresolved binary stars in the cluster, the rotation signal we detect is very likely to be genuine. Our observations are in qualitative agreement with the predictions of simulations modeling the formation of multiple populations of stars in globular clusters, where a dynamically cold, rapidly rotating second generation is a common feature. NGC 1846 is less than one relaxation time old, so any dynamical signatures encoded during its formation ought to remain present.

  18. The VLT-FLAMES Tarantula Survey III: A very massive star in apparent isolation from the massive cluster R136

    CERN Document Server

    Bestenlehner, Joachim M; Gräfener, G; Najarro, F; Evans, C J; Bastian, N; Bonanos, A Z; Bressert, E; Crowther, P A; Doran, E; Friedrich, K; Hénault-Brunet, V; Herrero, A; de Koter, A; Langer, N; Lennon, D J; Apellániz, J Maíz; Sana, H; Soszynski, I; Taylor, W D

    2011-01-01

    VFTS 682 is located in an active star-forming region, at a projected distance of 29 pc from the young massive cluster R136 in the Tarantula Nebula of the Large Magellanic Cloud. It was previously reported as a candidate young stellar object, and more recently spectroscopically revealed as a hydrogen-rich Wolf-Rayet (WN5h) star. Our aim is to obtain the stellar properties, such as its intrinsic luminosity, and to investigate the origin of VFTS 682. To this purpose, we model optical spectra from the VLT-FLAMES Tarantula Survey with the non-LTE stellar atmosphere code CMFGEN, as well as the spectral energy distribution from complementary optical and infrared photometry. We find the extinction properties to be highly peculiar (RV ~4.7), and obtain a surprisingly high luminosity log(L/Lsun) = 6.5 \\pm 0.2, corresponding to a present-day mass of ~150Msun. The high effective temperature of 52.2 \\pm 2.5kK might be explained by chemically homogeneous evolution - suggested to be the key process in the path towards long ...

  19. The VLT-FLAMES Tarantula Survey. XIII: On the nature of O Vz stars in 30 Doradus

    CERN Document Server

    Sabín-Sanjulián, C; Herrero, A; Walborn, N R; Puls, J; Apellániz, J Maíz; Evans, C J; Brott, I; de Koter, A; Garcia, M; Markova, N; Najarro, F; Ramírez-Agudelo, O H; Sana, H; Taylor, W D; Vink, J S

    2013-01-01

    AIMS. We test the hypothesis of O Vz stars (characterized by having HeII4686 stronger in absorption than other He lines in their blue-violet spectra) being at a younger evolutionary stage than are normal O-type dwarfs. METHODS. We have performed a quantitative spectroscopic analysis of a sample of 38 O Vz and 46 O V stars, identified by the VLT-FLAMES Tarantula Survey in the 30 Doradus region of the Large Magellanic Cloud (LMC). We obtained the stellar and wind parameters of both samples using the FASTWIND stellar atmosphere code and the IACOB-GBAT grid-based automatic tool. In the framework of a differential study, we compared the physical and evolutionary properties of both samples, regarding Teff, logg, logQ and logL. We also investigated the predictions of the FASTWIND code about the O Vz phenomenon. RESULTS. We find a differential distribution of objects in terms of effective temperature, with O Vz stars dominant at intermediate values. The O Vz stars in 30 Doradus tend to be younger and less luminous, a...

  20. The VLT-FLAMES Tarantula Survey. IX. The interstellar medium seen through Diffuse Interstellar Bands and neutral sodium

    CERN Document Server

    van Loon, Jacco Th; Tatton, Benjamin L; Apellaniz, Jesus Maiz; Crowther, Paul A; de Koter, Alex; Evans, Christopher J; Henault-Brunet, Vincent; Howarth, Ian D; Richter, Philipp; Sana, Hugues; Simon-Diaz, Sergio; Taylor, William; Walborn, Nolan R

    2012-01-01

    The Tarantula Nebula (30 Dor) is a spectacular star-forming region in the Large Magellanic Cloud, seen through gas in the Galactic Disc and Halo. Diffuse Interstellar Bands offer a unique probe of the diffuse, cool-warm gas in these regions. The aim is to use DIBs as diagnostics of the local interstellar conditions, whilst at the same time deriving properties of the yet-unknown carriers. Spectra of over 800 early-type stars from the VLT Flames Tarantula Survey (VFTS) were analysed. Maps were created, separately, for the Galactic and LMC absorption in the DIBs at 4428 and 6614 Ang and - in a smaller region near the central cluster R136 - neutral sodium (Na I D); we also measured the DIBs at 5780 and 5797 Ang. The maps show strong 4428 and 6614 Ang DIBs in the quiescent cloud complex to the south of 30 Dor but weak absorption in the harsher environments to the north (bubbles) and near the OB associations. The Na maps show at least five kinematic components in the LMC and a shell-like structure surrounding R136,...

  1. A VLT/MUSE view of the highly ionized outflow cones in the nearby starburst ESO338-IG04

    CERN Document Server

    Bik, A; Hayes, M; Adamo, A; Melinder, J; Amram, P

    2015-01-01

    Despite the fact that the Ly$\\alpha$ line is an important diagnostic for star formation at high redshift, the interpretation of its flux and line profile is difficult due to its resonance nature. Trends between the escape of Ly$\\alpha$ photons and dust and ISM properties have been found, but detailed comparisons between Ly$\\alpha$ emission and the properties of the gas in local high redshift analogues are vital to understand the relation between Ly$\\alpha$ emission and galaxy properties. For the first time we can directly infer the properties of the ionized gas at the same location and comparable spatial scales of the extended Ly$\\alpha$ halo around ESO 338-IG04. VLT/MUSE integral field spectra have been obtained. We use ionization parameter mapping of the [SII/OIII] line ratio and the kinematics of H$\\alpha$ to study the ionization state and kinematics of the interstellar medium of ESO 338. The velocity map reveals two outflows. The entire central area of the galaxy is highly ionized by photons leaking from ...

  2. VLT Diffraction Limited Imaging and Spectroscopy in the NIR: Weighing the black hole in Centaurus A with NACO

    CERN Document Server

    Haering-Neumayer, N; Rix, H W; Hartung, M; Prieto, M A; Meisenheimer, K; Lenzen, R

    2005-01-01

    We present high spatial resolution near-infrared spectra and images of the nucleus of Centaurus A (NGC 5128) obtained with NAOS-CONICA at the VLT. The adaptive optics corrected data have a spatial resolution of 0.06" (FWHM) in K- and 0.11" in H-band. The mean velocities and velocity dispersions of the ionized gas ([FeII]) are mapped along four slit positions. The observed gas motions suggest a kinematically hot disk which is orbiting a central object and is oriented nearly perpendicular to the nuclear jet. We model the central rotation and velocity dispersion curves of the [FeII] gas orbiting in the combined potential of the stellar mass and the (dominant) black hole. Our physically most plausible model, a dynamically hot and geometrically thin gas disk, yields a black hole mass of M_bh = (8.6 +/- 0.3) x 10^7 M_sun. As the physical state of the gas is not well understood, we also consider two limiting cases: first a cold disk model, which completely neglects the velocity dispersion, but is in line with many e...

  3. Probing the time-variation of the fine-structure constant: Results based on Si IV doublets from a UVES sample

    CERN Document Server

    Chand, H; Srianand, R; Aracil, B; Chand, Hum; Petitjean, Patrick; Srianand, Raghunathan; Aracil, Bastien

    2004-01-01

    We report a new constraint on the variation of the fine-structure constant based on the analysis of 15 Si IV doublets selected from a ESO-UVES sample. We find \\Delta\\alpha/\\alpha= +(0.15 +/- 0.43) 10^{-5} over a redshift range of 1.59< z < 2.92 which is consistent with no variation in \\alpha. This result represents a factor three improvement on the constraint on \\Delta\\alpha/\\alpha based on Si IV doublets compared to the published results in the literature. Alkali doublet method used here avoids the implicit assumptions used in the many-multiplet method that chemical and ionization homogeneities are negligible and isotopic abundances are close to the terrestrial value.

  4. Title: Near-UV behaviour of observed TNO reflectance spectra

    Science.gov (United States)

    Seccull, Tom; Fraser, Wesley Cristopher; Izawa, Matthew; Brown, Michael E.

    2016-10-01

    Observed spectra provide the best diagnostics of the surface compositions of Trans-Neptunian Objects (TNOs). We have observed the spectra of 7 TNOs, from across almost the full range of dynamical classes, using the VLT's X-Shooter spectrograph. Compared to the 5 targets in our sample which exhibit linear spectra in the UV-optical range, two of of our targets show highly unusual spectral behaviour, whereby their reflectance decreases sharply at wavelengths below ~440nm. Those same objects exhibit typically unremarkable spectra in the optical and near-IR spectral regions. In these regions where available, our observed spectra of the targets are in agreement with spectra or photometry available in the literature. Using a different solar analogue to produce our reflectance spectra does not remove the UV decrease exhibited by the two targets. Further, it appears that neither reducing the spectra with different pipelines, nor using drastically different parameters in those pipelines changes this general behaviour. Based on laboratory spectra of complex hydrocarbons it is plausible that the near-UV behaviour is the result of a surface coating of organic substances on the TNOs which exhibit it. The spectra of organics are also consistent in having a general red slope similar to that observed in the spectra of many TNOs. While laboratory spectra of some silicate substances also show a decrease in reflectance in the near-UV spectral region that is in principle consistent with our observations, those silicates do not exhibit a red slope consistent with our optical spectra. Hence, the hypothesis that silicates are present seems less likely than the hypothesis that this UV decrease is due to the presence of organics on the surfaces of these objects.

  5. Gaia-ESO Survey: The analysis of pre-main sequence stellar spectra

    CERN Document Server

    Lanzafame, A C; Damiani, F; Franciosini, E; Cottaar, M; Sousa, S G; Tabernero, H M; Klutsch, A; Spina, L; Biazzo, K; Prisinzano, L; Sacco, G G; Randich, S; Brugaletta, E; Mena, E Delgado; Adibekyan, V; Montes, D; Bonito, R; Gameiro, J F; Alcalá, J M; Hernández, J I González; Jeffries, R; Messina, S; Meyer, M; Gilmore, G; Asplund, M; Binney, J; Bonifacio, P; Drew, J E; Feltzing, S; Ferguson, A M N; Micela, G; Negueruela, I; Prusti, T; Rix, H-W; Vallenari, A; Alfaro, E J; Prieto, C Allende; Babusiaux, C; Bensby, T; Blomme, R; Bragaglia, A; Flaccomio, E; Francois, P; Hambly, N; Irwin, M; Koposov, S E; Korn, A J; Smiljanic, R; Van Eck, S; Walton, N; Bayo, A; Bergemann, M; Carraro, G; Costado, M T; Edvardsson, B; Heiter, U; Hill, V; Hourihane, A; Jackson, R J; Jofré, P; Lardo, C; Lewis, J; Lind, K; Magrini, L; Marconi, G; Martayan, C; Masseron, T; Monaco, L; Morbidelli, L; Sbordone, L; Worley, C C; Zaggia, S

    2015-01-01

    This paper describes the analysis of UVES and GIRAFFE spectra acquired by the Gaia-ESO Public Spectroscopic Survey in the fields of young clusters whose population includes pre-main sequence (PMS) stars. Both methods that have been extensively used in the past and new ones developed in the contest of the Gaia-ESO survey enterprise are available and used. The internal precision of these quantities is estimated by inter-comparing the results obtained by such different methods, while the accuracy is estimated by comparison with independent external data, like effective temperature and surface gravity derived from angular diameter measurements, on a sample of benchmarks stars. Specific strategies are implemented to deal with fast rotation, accretion signatures, chromospheric activity, and veiling. The analysis carried out on spectra acquired in young clusters' fields during the first 18 months of observations, up to June 2013, is presented in preparation of the first release of advanced data products. Stellar par...

  6. Estimating phase errors from pupil discontinuities from simulated on sky data: examples with VLT and Keck

    Science.gov (United States)

    Lamb, Masen; Correia, Carlos; Sauvage, Jean-François; Véran, Jean-Pierre; Andersen, David; Vigan, Arthur; Wizinowich, Peter; van Dam, Marcos; Mugnier, Laurent; Bond, Charlotte

    2016-07-01

    We propose and apply two methods for estimating phase discontinuities for two realistic scenarios on VLT and Keck. The methods use both phase diversity and a form of image sharpening. For the case of VLT, we simulate the `low wind effect' (LWE) which is responsible for focal plane errors in low wind and good seeing conditions. We successfully estimate the LWE using both methods, and show that using both methods both independently and together yields promising results. We also show the use of single image phase diversity in the LWE estimation, and show that it too yields promising results. Finally, we simulate segmented piston effects on Keck/NIRC2 images and successfully recover the induced phase errors using single image phase diversity. We also show that on Keck we can estimate both the segmented piston errors and any Zernike modes affiliated with the non-common path.

  7. Uveíte por tuberculose em um centro de referência no Sudeste do Brasil Tuberculous uveitis at a referral center in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Wesley Ribeiro Campos

    2008-02-01

    Full Text Available OBJETIVO: Descrever a ocorrência de uveíte por tuberculose (UTB em um centro de referência em Minas Gerais, Brasil. MÉTODOS: Um total de 16 pacientes (idade > 15 anos atendidos consecutivamente de janeiro de 2001 a julho de 2004 no Centro de Referência de Uveíte do Estado de Minas Gerais para avaliação diagnóstica de uveíte foi selecionado para este estudo. Foram coletados dados demográficos e clínicos, assim como dados sobre avaliação para toxoplasmose, sífilis e doenças reumatológicas, teste tuberculínico e sorologia anti-HIV. RESULTADOS: Dos 16 pacientes, 11 (69% tinham UTB. História prévia de contato com tuberculose pulmonar foi relatada por 72% (8/11 dos pacientes do grupo com UTB e por 20% (1/5 dos pacientes do grupo sem UTB. Embora a razão de chances para essa associação tenha sido de 10,67 (IC95%: 0,59-398,66, o valor de p apresentou significância limítrofe (0,078. Não houve diferença quanto ao quadro ocular inflamatório e ao resultado do teste tuberculínico entre os pacientes com UTB e os sem UTB. Todos os pacientes tinham sorologia negativa para o HIV e foram acompanhados por 2 anos. CONCLUSÕES: Neste estudo, a história prévia de contato com tuberculose pulmonar foi de grande ajuda para o diagnóstico da UTB.OBJECTIVE: To describe the occurrence of tuberculous uveitis (TBU at a referral center in the state of Minas Gerais, Brazil. METHODS: A total of 16 consecutive patients (>15 years of age who underwent diagnostic evaluation of uveitis between January of 2001 and July of 2004 at the Minas Gerais State Referral Center were selected for study. Demographic and clinical data, as well as data related to screening for toxoplasmosis, syphilis, and rheumatologic diseases, together with the results of tuberculin skin testing and HIV testing, were collected. RESULTS: Of the16 patients evaluated, 11 (69% were found to have TBU. A history of contact with pulmonary tuberculosis was reported by 8 (72% of the 11

  8. Effects of a Video Lottery Terminal (VLT) Banner on Gambling: A Field Study

    Science.gov (United States)

    Gallagher, Timothy; Nicki, Richard; Otteson, Amy; Elliott, Heather

    2011-01-01

    The effects of a warning banner, informing patrons of the randomness of Video Lottery Terminal (VLT) outcomes, on gambling behaviour and beliefs were tested in a field setting using a mixed-model 2 x 3 design over a six-week period with 27 problem and 27 non-problem gamblers recruited from bars in a Canadian city with a population of 85,000.…

  9. Velocity fields of distant galaxies with FORS2 at the VLT

    CERN Document Server

    Ziegler, Bodo L; Da Rocha, Cristiano; Böhm, Asmus; Kapferer, Wolfgang; Kuntschner, Harald; Peletier, Reynier F; Schindler, Sabine; Verdugo, Miguel

    2009-01-01

    We describe a method to efficiently obtain two-dimensional velocity fields of distant, faint and small, emission-line galaxies with FORS2 at the VLT. They are examined for kinematic substructure to identify possible interaction processes. Numerical simulations of tidal interactions and ram-pressure effects reveal distinct signatures observable with our method. We detect a significant fraction of galaxies with irregular velocity fields both in the field and cluster environments.

  10. MOONS: a Multi-Object Optical and Near-infrared Spectrograph for the VLT

    CERN Document Server

    Cirasuolo, M; Bender, R; Bonifacio, P; Evans, C; Kaper, L; Oliva, E; Vanzi, L; Abreu, M; Atad-Ettedgui, E; Babusiaux, C; Bauer, F; Best, P; Bezawada, N; Bryson, I; Cabral, A; Caputi, K; Centrone, M; Chemla, F; Cimatti, A; Cioni, M-R; Clementini, G; Coelho, J; Daddi, E; Dunlop, J; Feltzing, S; Ferguson, A; Flores, H; Fontana, A; Fynbo, J; Garilli, B; Glauser, A; Guinouard, I; Hammer, F; Hastings, P; Hess, A; Ivison, R; Jagourel, P; Jarvis, M; Kauffman, G; Lawrence, A; Lee, D; Licausi, G; Lilly, S; Lorenzetti, D; Maiolino, R; Mannucci, F; McLure, R; Minniti, D; Montgomery, D; Muschielok, B; Nandra, K; Navarro, R; Norberg, P; Origlia, L; Padilla, N; Peacock, J; Pedicini, F; Pentericci, L; Pragt, J; Puech, M; Randich, S; Renzini, A; Ryde, N; Rodrigues, M; Royer, F; Saglia, R; Sanchez, A; Schnetler, H; Sobral, D; Speziali, R; Todd, S; Tolstoy, E; Torres, M; Venema, L; Vitali, F; Wegner, M; Wells, M; Wild, V; Wright, G

    2012-01-01

    MOONS is a new conceptual design for a Multi-Object Optical and Near-infrared Spectrograph for the Very Large Telescope (VLT), selected by ESO for a Phase A study. The baseline design consists of 1000 fibers deployable over a field of view of 500 square arcmin, the largest patrol field offered by the Nasmyth focus at the VLT. The total wavelength coverage is 0.8um-1.8um and two resolution modes: medium resolution and high resolution. In the medium resolution mode (R=4,000-6,000) the entire wavelength range 0.8um-1.8um is observed simultaneously, while the high resolution mode covers simultaneously three selected spectral regions: one around the CaII triplet (at R=8,000) to measure radial velocities, and two regions at R=20,000 one in the J-band and one in the H-band, for detailed measurements of chemical abundances. The grasp of the 8.2m Very Large Telescope (VLT) combined with the large multiplex and wavelength coverage of MOONS - extending into the near-IR - will provide the observational power necessary to...

  11. A valiant little terminal: A VLT user`s manual. Revision 4

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, A.

    1992-08-01

    VLT came to be used at SLAC (Stanford Linear Accelerator Center), because SLAC wanted to assess the Amiga`s usefulness as a color graphics terminal and T{sub E}X workstation. Before the project could really begin, the people at SLAC needed a terminal emulator which could successfully talk to the IBM 3081 (now the IBM ES9000-580) and all the VAXes on the site. Moreover, it had to compete in quality with the Ann Arbor Ambassador GXL terminals which were already in use at the laboratory. Unfortunately, at the time there was no commercial program which fit the bill. Luckily, Willy Langeveld had been independently hacking up a public domain VT100 emulator written by Dave Wecker et al. and the result, VLT, suited SLAC`s purpose. Over the years, as the program was debugged and rewritten, the original code disappeared, so that now, in the present version of VLT, none of the original VT100 code remains.

  12. A valiant little terminal: A VLT user's manual

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, A.

    1992-08-01

    VLT came to be used at SLAC (Stanford Linear Accelerator Center), because SLAC wanted to assess the Amiga's usefulness as a color graphics terminal and T{sub E}X workstation. Before the project could really begin, the people at SLAC needed a terminal emulator which could successfully talk to the IBM 3081 (now the IBM ES9000-580) and all the VAXes on the site. Moreover, it had to compete in quality with the Ann Arbor Ambassador GXL terminals which were already in use at the laboratory. Unfortunately, at the time there was no commercial program which fit the bill. Luckily, Willy Langeveld had been independently hacking up a public domain VT100 emulator written by Dave Wecker et al. and the result, VLT, suited SLAC's purpose. Over the years, as the program was debugged and rewritten, the original code disappeared, so that now, in the present version of VLT, none of the original VT100 code remains.

  13. First light of the VLT planet finder SPHERE. II. The physical properties and the architecture of the young systems PZ Telescopii and HD 1160 revisited

    Science.gov (United States)

    Maire, A.-L.; Bonnefoy, M.; Ginski, C.; Vigan, A.; Messina, S.; Mesa, D.; Galicher, R.; Gratton, R.; Desidera, S.; Kopytova, T. G.; Millward, M.; Thalmann, C.; Claudi, R. U.; Ehrenreich, D.; Zurlo, A.; Chauvin, G.; Antichi, J.; Baruffolo, A.; Bazzon, A.; Beuzit, J.-L.; Blanchard, P.; Boccaletti, A.; de Boer, J.; Carle, M.; Cascone, E.; Costille, A.; De Caprio, V.; Delboulbé, A.; Dohlen, K.; Dominik, C.; Feldt, M.; Fusco, T.; Girard, J. H.; Giro, E.; Gisler, D.; Gluck, L.; Gry, C.; Henning, T.; Hubin, N.; Hugot, E.; Jaquet, M.; Kasper, M.; Lagrange, A.-M.; Langlois, M.; Le Mignant, D.; Llored, M.; Madec, F.; Martinez, P.; Mawet, D.; Milli, J.; Möller-Nilsson, O.; Mouillet, D.; Moulin, T.; Moutou, C.; Origné, A.; Pavlov, A.; Petit, C.; Pragt, J.; Puget, P.; Ramos, J.; Rochat, S.; Roelfsema, R.; Salasnich, B.; Sauvage, J.-F.; Schmid, H. M.; Turatto, M.; Udry, S.; Vakili, F.; Wahhaj, Z.; Weber, L.; Wildi, F.

    2016-03-01

    Context. The young systemsPZ Tel and HD 1160, hosting known low-mass companions, were observed during the commissioning of the new planet finder of the Very Large Telescope (VLT) SPHERE with several imaging and spectroscopic modes. Aims: We aim to refine the physical properties and architecture of both systems. Methods: We use SPHERE commissioning data and dedicated Rapid Eye Mount (REM) observations, as well as literature and unpublished data from VLT/SINFONI, VLT/NaCo, Gemini/NICI, and Keck/NIRC2. Results: We derive new photometry and confirm the short-term (P = 0.94 d) photometric variability of the star PZ Tel A with values of 0.14 and 0.06 mag at optical and near-infrared wavelengths, respectively. We note from the comparison to literature data spanning 38 yr that the star also exhibits a long-term variability trend with a brightening of ~0.25 mag. The 0.63-3.8 μm spectral energy distribution of PZ Tel B (separation ~25 AU) allows us to revise its physical characteristics: spectral type M7 ± 1, Teff = 2700 ± 100 K, log(g) 0.66). For eccentricities below 0.9, the inclination, longitude of the ascending node, and time of periastron passage are well constrained. In particular, both star and companion inclinations are compatible with a system seen edge-on. Based on "hot-start" evolutionary models, we reject other brown dwarf candidates outside 0.25'' for both systems, and giant planet companions outside 0.5'' that are more massive than 3 MJ for the PZ Tel system. We also show that K1-K2 color can be used along with YJH low-resolution spectra to identify young L-type companions, provided high photometric accuracy (≤0.05 mag) is achieved. Conclusions: SPHERE opens new horizons in the study of young brown dwarfs and giant exoplanets using direct imaging thanks to high-contrast imaging capabilities at optical (0.5-0.9 μm) and near-infrared (0.95-2.3 μm) wavelengths, as well as high signal-to-noise spectroscopy in the near-infrared domain (0.95-2.3 μm) from low

  14. SINFONI/VLT 3D spectroscopy of massive galaxies: evidence of rotational support at z ˜ 1.4

    Science.gov (United States)

    Buitrago, Fernando; Conselice, Christopher J.; Epinat, Benoît; Bedregal, Alejandro G.; Grützbauch, Ruth; Weiner, Benjamin J.

    2014-04-01

    There is cumulative evidence showing that, for the most massive galaxies, the fraction of disc-like objects compared to those with spheroidal properties increases with redshift. However, this evolution is thus far based on the surface brightness study of these objects. To explore the consistency of this scenario, it is necessary to measure the dynamical status of these galaxies. With this aim, we have obtained seeing-limited near-infrared integral-field spectra in the H-band for 10 massive galaxies (M_{*}≥ 10^{11} h_{70}^{-2} M_{⊙}) at z ˜ 1.4 with SINFONI at the VLT. Our sample is selected by their stellar mass and EW[O II] > 15 Å, to secure their kinematic measurements, but without accounting for any morphological or flux criteria a priori. Through this 3D kinematic spectroscopy analysis, we find that half (i.e. 50 ± 7 per cent) of our galaxies are compatible with being rotationally supported discs, in agreement with previous morphological expectations. This is a factor of approximately 2 higher than what is observed in the present Universe for objects of the same stellar mass. Strikingly, the majority of our sample of massive galaxies show extended and fairly high rotational velocity maps, implying that massive galaxies acquire rapidly rotational support and hence gravitational equilibrium. Our sample also show evidence for ongoing interactions and mergers. Summarizing, massive galaxies at high-z show a significant diversity and must have continued evolution beyond the fading of stellar populations, to become their present-day counterparts.

  15. The ESO UVES Advanced Data Products Quasar Sample - VI. Sub-Damped Lyman-$\\alpha$ Metallicity Measurements and the Circum-Galactic Medium

    CERN Document Server

    Quiret, S; Zafar, T; Kulkarni, V P; Jenkins, E D; Milliard, B; Rahmani, H; Popping, A; Sandhya, R M; Turnshek, D A; Monier, E M

    2016-01-01

    The Circum-Galactic Medium (CGM) can be probed through the analysis of absorbing systems in the line-of-sight to bright background quasars. We present measurements of the metallicity of a new sample of 15 sub-damped Lyman-$\\alpha$ absorbers (sub-DLAs, defined as absorbers with 19.0 < log N(H I) < 20.3) with redshift 0.584 < $\\rm z_{abs}$ < 3.104 from the ESO Ultra-Violet Echelle Spectrograph (UVES) Advanced Data Products Quasar Sample (EUADP). We combine these results with other measurements from the literature to produce a compilation of metallicity measurements for 92 sub-DLAs as well as a sample of 362 DLAs. We apply a multi-element analysis to quantify the amount of dust in these two classes of systems. We find that either the element depletion patterns in these systems differ from the Galactic depletion patterns or they have a different nucleosynthetic history than our own Galaxy. We propose a new method to derive the velocity width of absorption profiles, using the modeled Voigt profile feat...

  16. Metals in the z~3 intergalactic medium: results from an ultra-high signal-to-noise ratio UVES quasar spectrum

    CERN Document Server

    D'Odorico, V; Pomante, E; Carswell, R F; Viel, M; Barai, P; Becker, G D; Calura, F; Cupani, G; Fontanot, F; Haehnelt, M G; Kim, T-S; Miralda-Escude, J; Rorai, A; Tescari, E; Vanzella, E

    2016-01-01

    In this work, we investigate the abundance and distribution of metals in the intergalactic medium (IGM) at $\\langle z \\rangle \\simeq 2.8$ through the analysis of an ultra-high signal-to-noise ratio UVES spectrum of the quasar HE0940-1050. In the CIV forest, our deep spectrum is sensitive at $3\\,\\sigma$ to lines with column density down to $\\log N_{\\rm CIV} \\simeq 11.4$ and in 60 percent of the considered redshift range down to $\\simeq11.1$. In our sample, all HI lines with $\\log N_{\\rm HI} \\ge 14.8$ show an associated CIV absorption. In the range $14.0 \\le \\log N_{\\rm HI} <14.8$, 43 percent of HI lines has an associated CIV absorption. At $\\log N_{\\rm HI} < 14.0$, the detection rates drop to $<10$ percent, possibly due to our sensitivity limits and not to an actual variation of the gas abundance properties. In the range $\\log N_{\\rm HI} \\ge 14$, we observe a fraction of HI lines with detected CIV a factor of 2 larger than the fraction of HI lines lying in the circum-galactic medium (CGM) of relativel...

  17. Uveíte das espondiloartropatias: prevalência e relação com doença articular Uveitis and spondyloarthritis: prevalence and relationship with joint disease

    Directory of Open Access Journals (Sweden)

    Thelma Larocca Skare

    2007-10-01

    Full Text Available OBJETIVOS: Estudar a prevalência de uveítes na população local de espondiloartropatias e sua relação temporal com achados articulares. MÉTODOS: Foram revisados prontuários de 77 pacientes com espondiloartropatias atendidos no ambulatório de reumatologia do Hospital Universitário Evangélico de Curitiba, para diagnóstico do tipo de espondiloartropatia, sexo, idade, presença e tipo de uveite, tempo decorrido entre as primeiras manifestações oculares e as articulares. RESULTADOS: Uveíte foi encontrada em 12 dos 77 pacientes (15,6%, sendo anterior em 83,3% dos casos. O aparecimento da uveíte foi semelhante em todas as formas de espondiloartropatia (p=0,27 e não sofreu influência do sexo do paciente (p=0,74. O tempo médio de aparecimento dos sintomas oculares em relação ao diagnóstico articular foi de 4,04 meses para artrite reativa e 73 meses para espondilite anquilosante (p=0,009. CONCLUSÕES: A uveíte encontrada em pacientes com espondiloartropatia é, na sua grande maioria, anterior. O aparecimento da uveíte em relação aos sintomas articulares é mais precoce em casos de artrite reativa do que em espondilite anquilosante.PURPOSE: To study uveitis prevalence in the local population with spondyloarthritis and its temporal relationship with joint complaints. METHODS: We reviewed seventy-seven charts of spondyloarthropathy patients from the rheumatology clinic of the "Hospital Universitário Evangélico de Curitiba" for spondyloarthritis class, patients' sex and age, occurrence of uveitis and its location and relationship between the first episode of uveitis and initial joint complaints. RESULTS: Uveitis was found in 12 of 77 patients (15.6% which was anterior in 83.3% of the cases, without preference for spondyloarthropathy class (p=0.72 and patients' sex (p=0.74. In patients with reactive arthritis, the mean time between uveitis appearance and joint complaints was 4.04 months and in ankylosing spondylitis 73 months (p=0

  18. pVLT-EGFP载体构建及其在巴西固氮螺菌(Azospirillum brasilense)的表达研究%Construction of an Expression Vector pVLT-EGFP and Its Expression in Azospirillum brasilense

    Institute of Scientific and Technical Information of China (English)

    巩涛; 王继雯; 杨文玲; 甄静; 刘莹莹; 李冠杰; 刘莉; 岳丹丹; 陈国参

    2015-01-01

    为了研究巴西固氮螺菌(Azospirillum brasilense)在植物体内的定殖,利用酶切连接的方法,以增强型绿色荧光蛋白(enhanced green fluorescent protein,EGFP)基因与表达栽体pVLT-33为基本元件,构建了重组表达载体pVLT-EGFP,电转巴西固氮螺菌R7细胞,并利用实时荧光定量PCR(qPCR)研究了不同温度、不同时间EGFP mRNA的表达情况.酶切及测序结果表明,成功构建了pVLT-EGFP载体,并在荧光显微镜下观察到绿色荧光蛋白表达;qPCR结果显示:30℃,诱导9hEGFP基因的表达水平最高.本研究成功构建了重组表达载体pVLT-EGFP,为实现pVLT-EGFP的可控表达及研究固氮菌在植物体内的定殖规律及促生长机理提供了一种有效的途径.

  19. XQ-100: A legacy survey of one hundred 3.5 z < 4.5 quasars observed with VLT/XSHOOTER

    CERN Document Server

    Lopez, S; Ellison, S L; Becker, G D; Christensen, L; Cupani, G; Denney, K D; Paris, I; Worseck, G; Berg, T A M; Cristiani, S; Dessauges-Zavadsky, M; Haehnelt, M; Hamann, F; Hennawi, J; Irsic, V; Kim, T -S; Lopez, P; Saust, R Lund; Menard, B; Perrotta, S; Prochaska, J X; Sanchez-Ramirez, R; Vestergaard, M; Viel, M; Wisotzki, L

    2016-01-01

    We describe the execution and data reduction of the European Southern Observatory Large Programme "Quasars and their absorption lines: a legacy survey of the high-redshift universe with VLT/XSHOOTER" (hereafter `XQ-100'). XQ-100 has produced and made publicly available an homogeneous and high-quality sample of echelle spectra of 100 QSOs at redshifts z~3.5-4.5 observed with full spectral coverage from 315 to 2500 nm at a resolving power ranging from R~4000 to 7000, depending on wavelength. The median signal-to-noise ratios are 33, 25 and 43, as measured at rest-frame wavelengths 1700, 3000 and 3600 Angstrom, respectively. This paper provides future users of XQ-100 data with the basic statistics of the survey, along with details of target selection, data acquisition and data reduction. The paper accompanies the public release of all data products, including 100 reduced spectra. XQ-100 is the largest spectroscopic survey to date of high-redshift QSOs with simultaneous rest-frame UV/optical coverage, and as such...

  20. Reactor Neutrino Spectra

    OpenAIRE

    Hayes, A. C.; Vogel, Petr

    2016-01-01

    We present a review of the antineutrino spectra emitted from reactors. Knowledge of these spectra and their associated uncertainties is crucial for neutrino oscillation studies. The spectra used to date have been determined either by converting measured electron spectra to antineutrino spectra or by summing over all of the thousands of transitions that make up the spectra, using modern databases as input. The uncertainties in the subdominant corrections to β-decay plague both methods, and we ...

  1. Searching for Brown Dwarf Outflows

    CERN Document Server

    Whelan, E T; Bacciotti, F; Randich, S; Natta, A

    2009-01-01

    As outflow activity in low mass protostars is strongly connected to ac- cretion it is reasonable to expect accreting brown dwarfs to also be driving out- flows. In the last three years we have searched for brown dwarf outflows using high quality optical spectra obtained with UVES on the VLT and the technique of spectro-astrometry. To date five brown dwarf outflows have been discovered. Here the method is discussed and the results to date outlined.

  2. High-resolution spectroscopy of RGB stars in the Sagittarius Streams. I. Radial velocities and chemical abundances

    OpenAIRE

    Monaco, L.; Bellazzini, M; Bonifacio, P.; A. Buzzoni; Ferraro, F. R.; Marconi, G; Sbordone, L.; S. Zaggia

    2006-01-01

    Context. The Sagittarius (Sgr) dwarf spheroidal galaxy is currently being disrupted under the strain of the Milky Way. A reliable reconstruction of Sgr star formation history can only be obtained by combining core and stream information. Aims. We present radial velocities for 67 stars belonging to the Sgr Stream. For 12 stars in the sample we also present iron (Fe) and $\\alpha$-element (Mg, Ca) abundances. Methods. Spectra were secured using different high resolution facilities: UVES@VLT, HAR...

  3. PC based PLCs and ethernet based fieldbus: the new standard platform for future VLT instrument control

    Science.gov (United States)

    Kiekebusch, Mario J.; Lucuix, Christian; Erm, Toomas M.; Chiozzi, Gianluca; Zamparelli, Michele; Kern, Lothar; Brast, Roland; Pirani, Werther; Reiss, Roland; Popovic, Dan; Knudstrup, Jens; Duchateau, Michel; Sandrock, Stefan; Di Lieto, Nicola

    2014-07-01

    ESO is currently in the final phase of the standardization process for PC-based Programmable Logical Controllers (PLCs) as the new platform for the development of control systems for future VLT/VLTI instruments. The standard solution used until now consists of a Local Control Unit (LCU), a VME-based system having a CPU and commercial and proprietary boards. This system includes several layers of software and many thousands of lines of code developed and maintained in house. LCUs have been used for several years as the interface to control instrument functions but now are being replaced by commercial off-the-shelf (COTS) systems based on BECKHOFF Embedded PCs and the EtherCAT fieldbus. ESO is working on the completion of the software framework that enables a seamless integration into the VLT control system in order to be ready to support upcoming instruments like ESPRESSO and ERIS, that will be the first fully VLT compliant instruments using the new standard. The technology evaluation and standardization process has been a long and combined effort of various engineering disciplines like electronics, control and software, working together to define a solution that meets the requirements and minimizes the impact on the observatory operations and maintenance. This paper presents the challenges of the standardization process and the steps involved in such a change. It provides a technical overview of how industrial standards like EtherCAT, OPC-UA, PLCOpen MC and TwinCAT can be used to replace LCU features in various areas like software engineering and programming languages, motion control, time synchronization and astronomical tracking.

  4. VLT transit and occultation photometry for the bloated planet CoRoT-1b

    OpenAIRE

    Gillon, Michaël; Demory, B. -O.; Triaud, A. H. M. J.; Barman, T; Hebb, L.; Montalban Iglesias, Josefa; Maxted, P.; Queloz, D; Deleuil, M.; Magain, Pierre

    2009-01-01

    We present VLT eclipse photometry for the giant planet CoRoT-1b. We observed a transit in the R-band filter and an occultation in a narrow filter centered on 2.09 microns. Our analysis of this new photometry and published radial velocities, in combination with stellar-evolutionary modeling, leads to a planetary mass and radius of 1.07 (+0.13,-0.18) M_Jup and 1.45 (+0.07,-0.13) R_Jup, confirming the very low density previously deduced from CoRoT photometry. The large occultation depth that we ...

  5. Trends and developments in VLT data papers as seen through telbib

    Science.gov (United States)

    Bordelon, Dominic; Grothkopf, Uta; Meakins, Silvia; Sterzik, Michael

    2016-07-01

    The ESO Telescope Bibliography (telbib; http://telbib.eso.org) is a database of refereed papers published by the ESO users community. It links data in the ESO Science Archive with the published literature, and vice versa. Developed and maintained by the ESO library, telbib also provides insights into the organization's research output and impact as measured through bibliometric studies. Numerous reports, statistics, and visualizatons derived from telbib help to understand the way in which the user community uses ESO/VLT data in publications. Based on selected use cases, we will showcase recent trends and developments.

  6. Sm-Nd and Rb-Sr Isotopic Studies of Meteorite Kalahari 009: An Old VLT Mare Basalt

    Science.gov (United States)

    Shih, C.-Y.; Nyquist, L. E.; Reese, Y.; Bischoff, A.

    2008-01-01

    Lunar meteorite Kalahari 009 is a fragmental basaltic breccia contain ing various very-low-Ti (VLT) mare basalt clasts embedded in a fine-g rained matrix of similar composition. This meteorite and lunar meteorite Kalahari 008, an anorthositic breccia, were suggested to be paired mainly due to the presence of similar fayalitic olivines in fragment s found in both meteorites. Thus, Kalahari 009 probably represents a VLT basalt that came from a locality near a mare-highland boundary r egion of the Moon, as compared to the typical VLT mare basalt samples collected at Mare Crisium during the Luna-24 mission. The concordant Sm-Nd and Ar-Ar ages of such a VLT basalt (24170) suggest that the extrusion of VLT basalts at Mare Crisium occurred 3.30 +/- 0.05 Ga ag o. Previous age results for Kalahari 009 range from approximately 4.2 Ga by its Lu-Hf isochron age to 1.70?0.04 Ga of its Ar-Ar plateau ag e. However, recent in-situ U-Pb dating of phosphates in Kalahari 009 defined an old crystallization age of 4.35+/- 0.15 Ga. The authors su ggested that Kalahari 009 represents a cryptomaria basalt. In this r eport, we present Sm-Nd and Rb-Sr isotopic results for Kalahari 009, discuss the relationship of its age and isotopic characteristics to t hose of other L-24 VLT mare basalts and other probable cryptomaria ba salts represented by Apollo 14 aluminous mare basalts, and discuss it s petrogenesis.

  7. The VIMOS VLT Deep Survey final data release: a spectroscopic sample of 35016 galaxies and AGN out to z~6.7 selected with 17.5<=i_{AB}<=24.75

    CERN Document Server

    Fevre, O Le; Cucciati, O; Garilli, B; Ilbert, O; Brun, V Le; Maccagni, D; Moreau, C; Scodeggio, M; Tresse, L; Zamorani, G; Adami, C; Arnouts, S; Bardelli, S; Bolzonella, M; Bondi, M; Bongiorno, A; Bottini, D; Cappi, A; Charlot, S; Ciliegi, P; Contini, T; de la Torre, S; Foucaud, S; Franzetti, P; Gavignaud, I; Guzzo, L; Iovino, A; Lemaux, B; McCracken, H J; Marano, B; Marinoni, C; Mazure, A; Mellier, Y; Merighi, R; Merluzzi, P; Paltani, S; Pello, R; Pollo, A; Pozzetti, L; Scaramella, R; Vergani, D; Vettolani, G; Zanichelli, A; Zucca, E

    2013-01-01

    We describe the completed VIMOS VLT Deep Survey, and the final data release of 35016 galaxies and type-I AGN with measured spectroscopic redshifts up to redshift z~6.7, in areas 0.142 to 8.7 square degrees, and volumes from 0.5x10^6 to 2x10^7h^-3Mpc^3. We have selected samples of galaxies based solely on their i-band magnitude reaching i_{AB}=24.75. Spectra have been obtained with VIMOS on the ESO-VLT, integrating 0.75h, 4.5h and 18h for the Wide, Deep, and Ultra-Deep nested surveys. A total of 1263 galaxies have been re-observed independently within the VVDS, and from the VIPERS and MASSIV surveys. They are used to establish the redshift measurements reliability, to assess completeness, and to provide a weighting scheme taking into account the survey selection function. We describe the main properties of the VVDS samples, and the VVDS is compared to other spectroscopic surveys. In total we have obtained spectroscopic redshifts for 34594 galaxies, 422 type-I AGN, and 12430 Galactic stars. The survey has enabl...

  8. CROMOS A cryogenic near-infrared, multi-object spectrometer for the VLT

    CERN Document Server

    Genzel, R; Tomono, D; Thatte, N; Eisenhauer, F; Lehnert, M; Tecza, M; Bender, R

    2001-01-01

    We discuss a cryogenic, multi-object near-infrared spectrometer as a second generation instrument for the VLT. The spectrometer combines 20 to 40 independent integral eld units (IFUs), which can be positioned by a cryogenic robot over the entire unvignetted eld of the VLT (~7'). Each IFU consists of a contiguous cluster of 20 to 30 pixels (0.15 to 0.25" per pixel). The individual IFUs have cold fore-optics and couple into the spectrograph with integrated bers-microlenses. The spectrometer has lambda/d-lambda~4000 and simultaneously covers the J-, H-, and K-bands with three HAWAII 2 detectors. The system is designed for operation both in seeing limited and MCAO modes. Its speed is approximately 3500 times greater than that of ISAAC and 60 times greater than NIRMOS (in H-band). The proposed instrument aims at a wide range of science, ranging from studies of galaxies/clusters in the high-z Universe (dynamics and star formation in z>1 galaxies, evolution of ellipticals, properties of distant, obscured far-IR and ...

  9. High-precision astrometry on the VLT/FORS1 at time scales of few days

    CERN Document Server

    Lazorenko, P F; Dominik, M; Pepe, F; Ségransan, D; Udry, S

    2007-01-01

    We investigate the accuracy of astrometric measurements with the VLT/FORS1 camera and consider potential applications. The study is based on two-epoch (2000 and 2002/2003) frame series of observations of a selected Galactic Bulge sky region that were obtained with FORS1 during four consecutive nights each. Reductions were carried out with a novel technique that eliminates atmospheric image motion and does not require a distinction between targets and reference objects. The positional astrometric precision was found to be limited only by the accuracy of the determination of the star photocentre, which is typically 200-300 microarcsec per single measurement for bright unsaturated stars B=18-19. Several statistical tests have shown that at time-scales of 1-4 nights the residual noise in measured positions is essentially a white noise with no systematic instrumental signature and no significant deviation from a Gaussian distribution. Some evidence of a good astrometric quality of the VLT for frames separated by t...

  10. Final binary star results from the ESO VLT Lunar occultations program

    Energy Technology Data Exchange (ETDEWEB)

    Richichi, A. [National Astronomical Research Institute of Thailand, 191 Siriphanich Bldg., Huay Kaew Road, Suthep, Muang, Chiang Mai 50200 (Thailand); Fors, O. [Departament Astronomia i Meteorologia and Institut de Ciències del Cosmos (ICC), Universitat de Barcelona (UB/IEEC), Martí i Franqués 1, E-08028 Barcelona (Spain); Cusano, F. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Ivanov, V. D., E-mail: andrea4work@gmail.com [European Southern Observatory, Ave. Alonso de Cordova 3107, Casilla 19001, Santiago 19 (Chile)

    2014-03-01

    We report on 13 subarcsecond binaries, detected by means of lunar occultations in the near-infrared at the ESO Very Large Telescope (VLT). They are all first-time detections except for the visual binary HD 158122, which we resolved for the first time in the near-infrared. The primaries have magnitudes in the range K = 4.5-10.0, and companions in the range K = 6.8-11.1. The magnitude differences have a median value of 2.4, with the largest being 4.6. The projected separations are in the range of 4-168 mas, with a median of 13 mas. We discuss and compare our results with the available literature. With this paper, we conclude the mining for binary star detections in the 1226 occultations recorded at the VLT with the ISAAC instrument. We expect that the majority of these binaries may be unresolvable by adaptive optics on current telescopes, and they might be challenging for long-baseline interferometry. However, they constitute an interesting sample for future larger telescopes and for astrometric missions such as GAIA.

  11. Probing unexplored territories with MUSE: a second generation instrument for the VLT

    CERN Document Server

    Bacon, R; Böhm, P; Boudon, D; Brau-Nogue, S; Caillier, P; Capoani, L; Carollo, C M; Champavert, N; Contini, T; Daguise, E; Dalle, D; Delabre, B; Devriendt, J; Dreizler, S; Du Bois, J; Dupieux, M; Dupin, J P; Emsellem, E; Ferruit, P; Franx, M; Gallou, G; Gerssen, J; Guiderdoni, B; Hahn, T; Hofmann, D; Jarno, A; Kelz, A; Köhler, C; Kollatschny, W; Kosmalski, J; Laurent, F; Lilly, S J; Lizon, J; Loupias, M; Lynn, S; Manescau, A; McDermid, R M; Monstein, C; Nicklas, H; Pares, L; Pasquini, L; Pecontal-Rousset, A; Pécontal, E; Pellò, R; Petit, C; Picat, J P; Popow, E; Quirrenbach, Andreas G; Reiss, R; Renault, E; Roth, M; Schaye, J; Soucail, G; Steinmetz, M; Stroebele, S; Stuik, R; Weilbacher, P; Wozniak, H; De Zeeuw, P T

    2006-01-01

    The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation VLT panoramic integral-field spectrograph under preliminary design study. MUSE has a field of 1x1 arcmin**2 sampled at 0.2x0.2 arcsec**2 and is assisted by the VLT ground layer adaptive optics ESO facility using four laser guide stars. The simultaneous spectral range is 465-930 nm, at a resolution of R~3000. MUSE couples the discovery potential of a large imaging device to the measuring capabilities of a high-quality spectrograph, while taking advantage of the increased spatial resolution provided by adaptive optics. This makes MUSE a unique and tremendously powerful instrument for discovering and characterizing objects that lie beyond the reach of even the deepest imaging surveys. MUSE has also a high spatial resolution mode with 7.5x7.5 arcsec**2 field of view sampled at 25 milli-arcsec. In this mode MUSE should be able to obtain diffraction limited data-cubes in the 600-930 nm wavelength range. Although the MUSE design has been optimized f...

  12. Using the VLT to analyze the compact photoionized regions in NGC 3109

    Directory of Open Access Journals (Sweden)

    M. Peña

    2007-01-01

    Full Text Available Veinte nebulosas planetarias (NP y numerosas regiones HII compactas fueron detectadas en la galaxia irregular NGC3109, mediante imágenes \\en-línea" y \\fuera de línea" en [O III] 5007 obtenidas con el ESO VLT. Las NPs fueron seleccionadas como objetos estelares que no mostraran continuo estelar. Espectroscopia obtenida con el VLT FORS1 en modo multi-objeto ha permitido confirmar la naturaleza de NP para varias candidatas. Se ha obtenido también espectroscopia para varias regiones HII compactas. Los espectros son profundos de manera que muchos objetos muestran [O III] 4363 y se puede determinar la temperatura de las regiones, permitiendo analizar la composición química de NPs y regiones HII. Encontramos que las regiones HII muestran una composición química (O/H muy homogénea (en promedio 12 + log O/H = 7.79_0.10, en tanto que las NPs muestran variaciones grandes de composición química y un aparente enriquecimiento en oxígeno.

  13. Development, validity, and normative data study for the 12-word Philadelphia Verbal Learning Test [czP(r)VLT-12] among older and very old Czech adults.

    Science.gov (United States)

    Bezdicek, Ondrej; Libon, David J; Stepankova, Hana; Panenkova, Erika; Lukavsky, Jiri; Garrett, Kelly Davis; Lamar, Melissa; Price, Catherine C; Kopecek, Miloslav

    2014-01-01

    The aim of the present study was to assess the validity of a 12-word Czech version of the Philadelphia (repeatable) Verbal Learning Test [czP(r)VLT-12]. The construction of the czP(r)VLT-12 was modeled after the California Verbal Learning Test (CVLT) and the nine-word Philadelphia (repeatable) Verbal Learning Test [P(r)VLT]. The czP(r)VLT-12 was constructed from a large corpus of old (60-74) and very old (75-96) Czech adults (n = 540). Participants met strict inclusion criteria for the absence of any active or past neurodegenerative disorders and performed within normal limits on other neuropsychological measures. Principal component analysis (PCA) and correlations between czP(r)VLT-12 factor structure and other memory tests were conducted. The czP(r)VLT-12 produced a four-factor solution, accounting for 70.90% of variance, with factors related to: (1) recall, (2) extra-list intrusion errors/recognition foils, (3) interference, and (4) acquisition rate; a solution similar to the CVLT and P(r)VLT. Increasing age resulted in a decline in most czP(r)VLT-12 indices, women outperformed men, and higher education led to higher scores. Memory performance in normal aging did not correlate with instrumental activities of daily living. Low, but significant, correlations were seen with other tests of cognitive performance (divergent validity). Appendices are available that provide normed percentile estimates of individual czP(r)VLT-12 performance stratified by age, education, and gender. In accordance with previous studies, these results demonstrate the usefulness of czP(r)VLT-12 in assessing declarative memory in older adults.

  14. La leflunomida, una alternativa válida para el tratamiento de la uveítis crónica anterior asociada a la Artritis Idiopática Juvenil

    OpenAIRE

    Molina Almela, Clara

    2012-01-01

    Donada la manca de consens davant el tractament de la uveítis crònica anterior (UCA) associada a la artritis idiopàtica juvenil (AIJ), aquest treball té com a objectiu valorar la possible eficàcia de la leflunomida (LFN) en aquesta malaltia. Per a això es va valorar la resposta al tractament de forma retrospectiva de 13 pacients amb UCA associada a AIJ de la cohort de 417 pacients de l'Hospital Universitari Vall d'Hebron. Els resultats obtinguts suggereixen que la LFN pot ser una alternativa ...

  15. VLT/GIRAFFE spectroscopic observations of the metal-poor blue compact dwarf galaxy SBS 0335-052E

    Science.gov (United States)

    Izotov, Y. I.; Schaerer, D.; Blecha, A.; Royer, F.; Guseva, N. G.; North, P.

    2006-11-01

    Aims.We present two-dimensional spectroscopy of the extremely metal-deficient blue compact dwarf (BCD) galaxy SBS 0335-052E to study physical conditions, element abundances and kinematical properties of the ionised gas in this galaxy. Methods: .Observations were obtained in the spectral range λ3620-9400 Å with the imaging spectrograph GIRAFFE on the UT2 of the Very Large Telescope (VLT). These observations are the first ones carried out so far with GIRAFFE in the ARGUS mode which allows one to simultaneously obtain 308 spectra covering a 11.4 arcsec×7.3 arcsec region. Results: .We produced images of SBS 0335-052E in the continuum and in emission lines of different stages of excitation. While the maximum of emission in the majority of lines, including the strong lines Hβ 4861 Å, Hα 6563 Å, [O iii] 4363,5007 Å, [O ii] 3726,3729 Å, coincides with the youngest south-eastern star clusters 1 and 2, the emission of He II 4686 Å line is offset to the more evolved north-west clusters 4, 5. This suggests that hard ionising radiation responsible for the He II λ4686 Å emission is not related to the most massive youngest stars, but rather is related to fast radiative shocks. This conclusion is supported by the kinematical properties of the ionised gas from the different emission lines as the velocity dispersion in the He II λ4686 Å line is systematically higher, by ~50-100%, than that in other lines. The variations of the emission line profiles suggest the presence of an ionised gas outflow in the direction perpendicular to the galaxy disk. We find a relatively high electron number density Ne of several hundred cm-3 in the brightest part of SBS 0335-052E. There is a small gradient of the electron temperature Te and oxygen abundance from the East to the West with systematically higher Te and lower 12+log O/H in the western part of the galaxy. The oxygen abundances for the whole H II region and its brightest part are 12 + log O/H = 7.29 ± 0.02 and 7.31 ± 0

  16. Fingerprints of endogenous process on Europa through linear spectral modeling of ground-based observations (ESO/VLT/SINFONI)

    Science.gov (United States)

    Ligier, Nicolas; Carter, John; Poulet, François; Langevin, Yves; Dumas, Christophe; Gourgeot, Florian

    2016-04-01

    Jupiter's moon Europa harbors a very young surface dated, based on cratering rates, to 10-50 M.y (Zahnle et al. 1998, Pappalardo et al. 1999). This young age implies rapid surface recycling and reprocessing, partially engendered by a global salty subsurface liquid ocean that could result in tectonic activity (Schmidt et al. 2011, Kattenhorn et al. 2014) and active plumes (Roth et al. 2014). The surface of Europa should contain important clues about the composition of this sub-surface briny ocean and about the potential presence of material of exobiological interest in it, thus reinforcing Europa as a major target of interest for upcoming space missions such as the ESA L-class mission JUICE. To perform the investigation of the composition of the surface of Europa, a global mapping campaign of the satellite was performed between October 2011 and January 2012 with the integral field spectrograph SINFONI on the Very Large Telescope (VLT) in Chile. The high spectral binning of this instrument (0.5 nm) is suitable to detect any narrow mineral signature in the wavelength range 1.45-2.45 μm. The spatially resolved spectra we obtained over five epochs nearly cover the entire surface of Europa with a pixel scale of 12.5 by 25 m.a.s (~35 by 70 km on Europa's surface), thus permitting a global scale study. Until recently, a large majority of studies only proposed sulfate salts along with sulfuric acid hydrate and water-ice to be present on Europa's surface. However, recent works based on Europa's surface coloration in the visible wavelength range and NIR spectral analysis support the hypothesis of the predominance of chlorine salts instead of sulfate salts (Hand & Carlson 2015, Fischer et al. 2015). Our linear spectral modeling supports this new hypothesis insofar as the use of Mg-bearing chlorines improved the fits whatever the region. As expected, the distribution of sulfuric acid hydrate is correlated to the Iogenic sulfur ion implantation flux distribution (Hendrix et al

  17. The VIMOS VLT Deep Survey :Evolution of the major merger rate since z~1 from spectroscopicaly confirmed galaxy pairs

    CERN Document Server

    de Ravel, L; Tresse, L; Bottini, D; Garilli, B; Le Brun, V; MacCagni, D; Scaramella, R; Scodeggio, M; Vettolani, G; Zanichelli, A; Adami, C; Arnouts, S; Bardelli, S; Bolzonella, M; Cappi, A; Charlot, S; Ciliegi, P; Contini, T; Foucaud, S; Franzetti, P; Gavignaud, I; Guzzo, L; Ilbert, O; Iovino, A; Lamareille, F; McCracken, H J; Marano, B; Marinoni, C; Mazure, A; Meneux, B; Merighi, R; Paltani, S; Pellò, R; Pollo, A; Pozzetti, L; Radovich, M; Vergani, D; Zamorani, G; Zucca, E; Bondi, M; Bongiorno, A; Brinchmann, J; Cucciati, O; De la Torre, S; Gregorini, L; Memeo, P; Pérez-Montero, E; Mellier, Y; Merluzzi, P; Temporin, S

    2008-01-01

    From the VIMOS VLT Deep Survey we use a sample of 6447 galaxies with I_{AB} 9.5 has been accreted through major merging events since z ~ 1, indicating that major mergers have contributed significantly to the growth in stellar mass density of bright galaxies over the last half of the life of the Universe.

  18. The VLT LBG Redshift Survey - I. Clustering and dynamics of approximate to 1000 galaxies at z approximate to 3

    NARCIS (Netherlands)

    Bielby, R. M.; Shanks, T.; Weilbacher, P. M.; Infante, L.; Crighton, N. H. M.; Bornancini, C.; Bouche, N.; Heraudeau, P.; Lambas, D. G.; Lowenthal, J.; Minniti, D.; Padilla, N.; Petitjean, P.; Theuns, T.

    2011-01-01

    We present the initial imaging and spectroscopic data acquired as part of the Very Large Telescope (VLT) VIMOS Lyman-break galaxy Survey. UBR (or UBVI) imaging covers five approximate to 36 x 36 arcmin(2) fields centred on bright z > 3 quasi-stellar objects (QSOs), allowing approximate to 21 000 2 <

  19. X-shooter: UV-to-IR intermediate-resolution high-efficiency spectrograph for the ESO VLT

    NARCIS (Netherlands)

    D'Odorico, S.; Andersen, M.I.; Conconi, P.; De Caprio, V.; Delabre, B.; Di Marcantonio, P.; Dekker, H.; Downing, M.D.; Finger, G.; Groot, P.; Hanenburg, H.H.; Hammer, F.; Horville, D.; Hjorth, J.; Kaper, L.; Klougart, J.; Kjaergaard-Rasmussen, P.; Lizon, J.-L.; Marteaud, M.; Mazzoleni, R.; Michaelsen, N.; Pallavicini, R.; Rigal, F.; Santin, P.; Norup Soerensen, A.; Spano, P.; Venema, L.; Vola, P.; Zerbi, F.M.; Hasinger, G.; Turner, M.J.L.

    2004-01-01

    X-shooter is a single target spectrograph for the Cassegrain focus of one of the VLT UTs. It covers in a single exposure the spectral range from the UV to the H band with a possible extension into part of the K band. It is designed to maximize the sensitivity in this spectral range through the

  20. VizieR Online Data Catalog: O-stars in VLT-FLAMES Tarantula Survey (Ramirez-Agudelo+ 2013)

    Science.gov (United States)

    Ramirez-Agudelo, O. H.; Simon-Diaz, S.; Sana, H.; de Koter, A.; Sabin-Sanjulian, C.; de Mink, S. E.; Dufton, P. L.; Grafener, G.; Evans, C. J.; Herrero, A.; Langer, N.; Lennon, D. J.; Maiz Apellaniz, J.; Markova, N.; Najarro, F.; Puls, J.; Vink, J. S.

    2013-09-01

    Projected rotational velocity measurements of 216 O-type stars observed at multi-epochs as part as the VLT-FLAMES Tarantula Survey. We measured projected rotational velocities by means of a Fourier transform method and a profile fitting method applied on a set of isolated spectral lines. (2 data files).

  1. Design, analysis and testing of the Optical Tube Assemblies for the ESO VLT Four Laser Guide Star Facility

    NARCIS (Netherlands)

    Henselmans, R.; Nijkerk, M.D.; Lemmen, M.H.J.; Rijnveld, N.; Kamphues, F.G.

    2012-01-01

    TNO has developed the Optical Tube Assemblies (OTAs) for the ESO VLT Four Laser Guide Star Facility. The OTAs are Galilean 20x beam expanders, expanding a ∅15 mm input beam (25W, 589 nm CW) to a steerable ∅300 mm output beam. TNO has recently successfully completed acceptance testing of the four uni

  2. A high-resolution VLT/FLAMES study of individual stars in the centre of the Fornax dwarf spheroidal galaxy

    NARCIS (Netherlands)

    Letarte, B.; Hill, V.; Tolstoy, E.; Jablonka, P.; Shetrone, M.; Venn, K. A.; Spite, M.; Irwin, M. J.; Battaglia, G.; Helmi, A.; Primas, F.; François, P.; Kaufer, A.; Szeifert, T.; Arimoto, N.; Sadakane, K.

    2010-01-01

    For the first time we show the detailed, late-stage, chemical evolution history of a small nearby dwarf spheroidal galaxy in the Local Group. We present the results of a high-resolution (R ~ 20 000, λ = 5340-5620; 6120-6701) FLAMES/GIRAFFE abundance study at ESO/VLT of 81 photometrically selected, r

  3. A high-resolution VLT/FLAMES study of individual stars in the centre of the Fornax dwarf spheroidal galaxy

    NARCIS (Netherlands)

    Letarte, B.; Hill, V.; Tolstoy, E.; Jablonka, P.; Shetrone, M.; Venn, K. A.; Spite, M.; Irwin, M. J.; Battaglia, G.; Helmi, A.; Primas, F.; François, P.; Kaufer, A.; Szeifert, T.; Arimoto, N.; Sadakane, K.

    2010-01-01

    For the first time we show the detailed, late-stage, chemical evolution history of a small nearby dwarf spheroidal galaxy in the Local Group. We present the results of a high-resolution (R similar to 20 000, lambda = 5340-5620; 6120-6701) FLAMES/GIRAFFE abundance study at ESO/VLT of 81 photometrical

  4. Revisiting the Impact of Atmospheric Dispersion and Differential Refraction on Widefield Multiobject Spectroscopic Observations. From VLT/VIMOS to Next Generation Instruments

    CERN Document Server

    Sánchez-Janssen, Rubén; Selman, Fernando; Bristow, Paul; Hammersley, Peter; Hilker, Michael; Rejkuba, Marina; Wolff, Burkhard

    2014-01-01

    (Abridged) Atmospheric dispersion and field differential refraction impose severe constraints on widefield MOS observations. Flux reduction and spectral distortions must be minimised by a careful planning of the observations -- which is especially true for instruments that use slits instead of fibres. This is the case of VIMOS at the VLT, where MOS observations have been restricted, since the start of operations, to a narrow two-hour range from the meridian to minimise slit losses. We revisit in detail the impact of atmospheric effects on the quality of VIMOS-MOS spectra. We model slit losses across the entire VIMOS FOV as a function of target declination. We explore two different slit orientations at the meridian: along the parallactic angle (North-South), and perpendicular to it (East-West). We show that, for fields culminating at zenith distances larger than 20 deg, slit losses are minimised with slits oriented along the parallactic angle at the meridian. The two-hour angle rule holds for these observation...

  5. The Extended Chandra Deep Field-South Survey: Optical spectroscopy of faint X-ray sources with the VLT and Keck

    CERN Document Server

    Silverman, J D; Salvato, M; Hasinger, G; Bergeron, J; Capak, P; Szokoly, G; Finoguenov, A; Gilli, R; Rosati, P; Tozzi, P; Vignali, C; Alexander, D M; Brandt, W N; Lehmer, B D; Luo, B; Rafferty, D; Xue, Y Q; Balestra, I; Bauer, F E; Brusa, M; Comastri, A; Kartaltepe, J; Koekemoer, A M; Miyaji, T; Schneider, D P; Treister, E; Wisotski, L; Schramm, M

    2010-01-01

    We present the results of a program to acquire high-quality optical spectra of X-ray sources detected in the E-CDF-S and its central area. New spectroscopic redshifts are measured for 283 counterparts to Chandra sources with deep exposures (t~2-9 hr per pointing) using multi-slit facilities on both the VLT and Keck thus bringing the total number of spectroscopically-identified X-ray sources to over 500 in this survey field. We provide a comprehensive catalog of X-ray sources detected in the E-CDF-S including the optical and near-infrared counterparts, and redshifts (both spectroscopic and photometric) that incorporate published spectroscopic catalogs thus resulting in a final sample with a high fraction (80%) of X-ray sources having secure identifications. We demonstrate the remarkable coverage of the Lx-z plane now accessible from our data while emphasizing the detection of AGNs that contribute to the faint end of the luminosity function at 1.5

  6. VLT multi-object spectroscopy of 33 eclipsing binaries in the Small Magellanic Cloud. New distance and depth of the SMC, and a record-breaking apsidal motion

    CERN Document Server

    North, P L; Barblan, F; Royer, F

    2010-01-01

    Aim: Our purpose is to provide reliable stellar parameters for a significant sample of eclipsing binaries, which are representative of a whole dwarf and metal-poor galaxy. We also aim at providing a new estimate of the mean distance to the SMC and of its depth along the line of sight for the observed field of view. Method: We use radial velocity curves obtained with the ESO FLAMES facility at the VLT and light curves from the OGLE-II photometric survey. The radial velocities were obtained by least-squares fits of the observed spectra to synthetic ones, excluding the hydrogen Balmer lines. Results: Our sample contains 23 detached, 9 semi-detached and 1 overcontact systems. Most detached systems have properties consistent with stellar evolution calculations from single-star models at the standard SMC metallicity Z = 0.004, though they tend to be slightly overluminous. The few exceptions are probably due to third light contribution or insufficient signal-to-noise ratio. The mass ratios are consistent with a flat...

  7. CLASH-VLT: spectroscopic confirmation of a z=6.11 quintuply lensed galaxy in the Frontier Fields Cluster RXC J2248.7-4431

    CERN Document Server

    Balestra, I; Rosati, P; Monna, A; Grillo, C; Nonino, M; Mercurio, A; Biviano, A; Bradley, L; Coe, D; Fritz, A; Postman, M; Seitz, S; Scodeggio, M; Zheng, W; Ziegler, B; Zitrin, A; Annunziatella, M; Bartelmann, M; Benitez, N; Broadhurst, T; Bouwens, R; Czoske, O; Donahue, M; Ford, H; Girardi, M; Infante, L; Kelson, D; Koekemoer, A; Kuchner, U; Lemze, D; Lombardi, M; Maier, C; Medezinski, E; Melchior, P; Meneghetti, M; Merten, J; Moustakas, L; Presotto, V; Smit, R; Tozzi, P; Umetsu, K

    2013-01-01

    We present VIsible Multi-Object Spectrograph (VIMOS) observations of a z 6 galaxy quintuply imaged by the Frontier Fields galaxy cluster RXC J2248.7-4431 (z=0.348). This sub-L^*, high-z galaxy has been recently discovered by Monna et al. (2013) using dropout techniques with the 16-band HST photometry acquired as part of the Cluster Lensing And Supernova survey with Hubble (CLASH). Obtained as part of the CLASH-VLT survey, the VIMOS medium-resolution spectra of this source show a very faint continuum between ~8700A and ~9300A and a prominent emission line at 8643A, which can be readily identified with Lyman-alpha at z=6.110. The emission line exhibits an asymmetric profile, with a more pronounced red wing. The rest-frame equivalent width of the line is EW=79+-10A. After correcting for magnification, the star-formation rate (SFR) estimated from the Lya line is SFR(Lya)=11 M_{sol}/yr and that estimated from the UV data is SFR(UV)=3 M$_{sol}/yr. We estimate that the effective radius of the source is R_e6 M$_{sol}...

  8. Direct exoplanet detection and characterization using the ANDROMEDA method: Performance on VLT/NaCo data

    Science.gov (United States)

    Cantalloube, F.; Mouillet, D.; Mugnier, L. M.; Milli, J.; Absil, O.; Gomez Gonzalez, C. A.; Chauvin, G.; Beuzit, J.-L.; Cornia, A.

    2015-10-01

    Context. The direct detection of exoplanets with high-contrast imaging requires advanced data processing methods to disentangle potential planetary signals from bright quasi-static speckles. Among them, angular differential imaging (ADI) permits potential planetary signals with a known rotation rate to be separated from instrumental speckles that are either statics or slowly variable. The method presented in this paper, called ANDROMEDA for ANgular Differential OptiMal Exoplanet Detection Algorithm, is based on a maximum likelihood approach to ADI and is used to estimate the position and the flux of any point source present in the field of view. Aims: In order to optimize and experimentally validate this previously proposed method, we applied ANDROMEDA to real VLT/NaCo data. In addition to its pure detection capability, we investigated the possibility of defining simple and efficient criteria for automatic point source extraction able to support the processing of large surveys. Methods: To assess the performance of the method, we applied ANDROMEDA on VLT/NaCo data of TYC-8979-1683-1 which is surrounded by numerous bright stars and on which we added synthetic planets of known position and flux in the field. In order to accommodate the real data properties, it was necessary to develop additional pre-processing and post-processing steps to the initially proposed algorithm. We then investigated its skill in the challenging case of a well-known target, β Pictoris, whose companion is close to the detection limit and we compared our results to those obtained by another method based on principal component analysis (PCA). Results: Application on VLT/NaCo data demonstrates the ability of ANDROMEDA to automatically detect and characterize point sources present in the image field. We end up with a robust method bringing consistent results with a sensitivity similar to the recently published algorithms, with only two parameters to be fine tuned. Moreover, the companion flux

  9. A new method for detecting velocity shifts and distortions between optical spectra

    CERN Document Server

    Evans, Tyler M

    2013-01-01

    Recent quasar spectroscopy from the VLT and Keck telescopes suggests that fundamental constants may not actually be constant. To better confirm or refute this result, systematic errors between telescopes must be minimized. We present a new method to directly compare spectra of the same object and measure any velocity shifts between them. This method allows for the discovery of wavelength-dependent velocity shifts between spectra, i.e. velocity distortions, that could produce spurious detections of cosmological variations in fundamental constants. This "direct comparison" method has several advantages over alternative techniques: it is model-independent (cf. line-fitting approaches), blind, in that spectral features do not need to be identified beforehand, and it produces meaningful uncertainty estimates for the velocity shift measurements. In particular, we demonstrate that, when comparing echelle-resolution spectra with unresolved absorption features, the uncertainty estimates are reliable for signal-to-nois...

  10. Status and new operation modes of the versatile VLT/NACO

    CERN Document Server

    Girard, Julien H V; Quanz, Sascha P; Kenworthy, Matthew A; Rengaswamy, Sridharan; Schödel, Rainer; Gallenne, Alexandre; Gillessen, Stefan; Huerta, Nicolas; Kervella, Pierre; Kornweibel, Nick; Lenzen, Rainer; Mérand, Antoine; Montagnier, Guillaume; O'Neal, Jared; Zins, Gérard; IOT, the NACO; 10.1117/12.856799

    2010-01-01

    This paper aims at giving an update on the most versatile adaptive optics fed instrument to date, the well known and successful NACO . Although NACO is only scheduled for about two more years at the Very Large Telescope (VLT), it keeps on evolving with additional operation modes bringing original astronomical results. The high contrast imaging community uses it creatively as a test-bench for SPHERE and other second generation planet imagers. A new visible wavefront sensor (WFS) optimized for Laser Guide Star (LGS) operations has been installed and tested, the cube mode is more and more requested for frame selection on bright sources, a seeing enhancer mode (no tip/tilt correction) is now offered to provide full sky coverage and welcome all kind of extragalactic applications, etc. The Instrument Operations Team (IOT) and Paranal engineers are currently working hard at maintaining the instrument overall performances but also at improving them and offering new capabilities, providing the community with a well tu...

  11. Developing an instrument simulator: experience feedback from the JWST/NIRSpec and VLT/MUSE simulators

    Science.gov (United States)

    Jarno, Aurélien; Piqueras, Laure; Bacon, Roland; Ferruit, Pierre; Legros, Emeline; Pécontal-Rousset, Arlette; Gnata, Xavier; Streicher, Ole; Weilbacher, Peter

    2012-09-01

    The Centre de Recherche Astrophysique de Lyon (CRAL) has recently developed two instrument simulators for spectrographic instruments. They are based on Fourier optics, and model the whole chain of acquisition, taking into account both optical aberrations and diffraction effects, by propagating a wavefront through the instrument, according to the Fourier optics concept. One simulates the NIRSpec instrument, a near-infrared multi-object spectrograph for the future James Webb Space Telescope (JWST). The other one models the Multi Unit Spectroscopic Explorer (MUSE) instrument, a second-generation integral-field spectrograph for the Very Large Telescope (VLT). The two simulators have been developed in different contexts (subcontracted versus developed internally), and for very different instruments (space-based versus ground-based), which strengthen the CRAL experience. This paper describes the lessons learned while developing these simulators: development methods, phasing with the project, points to focus on, getting data, interacting with scientists and users, etc.

  12. Validation Through Simulations of a Cn2 Profiler for the ESO/VLT Adaptive Optics Facility

    CERN Document Server

    Garcia-Rissmann, A; Kolb, J; Louarn, M Le; Madec, P -Y; Neichel, B

    2015-01-01

    The Adaptive Optics Facility (AOF) project envisages transforming one of the VLT units into an adaptive telescope and providing its ESO (European Southern Observatory) second generation instruments with turbulence corrected wavefronts. For MUSE and HAWK-I this correction will be achieved through the GALACSI and GRAAL AO modules working in conjunction with a 1170 actuators Deformable Secondary Mirror (DSM) and the new Laser Guide Star Facility (4LGSF). Multiple wavefront sensors will enable GLAO and LTAO capabilities, whose performance can greatly benefit from a knowledge about the stratification of the turbulence in the atmosphere. This work, totally based on end-to-end simulations, describes the validation tests conducted on a Cn2 profiler adapted for the AOF specifications. Because an absolute profile calibration is strongly dependent on a reliable knowledge of turbulence parameters r0 and L0, the tests presented here refer only to normalized output profiles. Uncertainties in the input parameters inherent t...

  13. NIX, the imager for ERIS: the AO instrument for the VLT

    Science.gov (United States)

    Pearson, David; Taylor, William; Davies, Ric; MacIntosh, Mike; Henry, David; Lunney, David; Waring, Chris; Gao, Xiaofeng; Lightfoot, John; Glauser, Adrian M.; Quanz, Sascha P.; Meyer, Michael R.; Schmid, Hans Martin; March, Stephen; Bachmann, Walter; Feuchtgruber, Helmut; George, Elizabeth; Sturm, Eckhard; Biller, Beth; Hinckley, Sasha; Kenworthy, Matthew; Amico, Paola; Glindemann, Andreas; Kasper, Marcus; Kuntschner, Harald; Dorn, Reinhold; Egner, Sebastian

    2016-08-01

    ERIS will be the next-generation AO facility on the VLT, combining the heritage of NACO imaging, with the spectroscopic capabilities of an upgraded SINFONI. Here we report on the all-new NIX imager that will deliver diffraction-limited imaging from the J to M band. The instrument will be equipped with both Apodizing Phase Plates and Sparse Aperture Masks to provide high-angular resolution imagery, especially suited for exoplanet imaging and characterization. This paper provides detail on the instrument's design and how it is suited to address a broad range of science cases, from detailed studies of the galactic centre at the highest resolutions, to studying detailed resolved stellar populations.

  14. VLT transit and occultation photometry for the bloated planet CoRoT-1b

    CERN Document Server

    Gillon, M; Triaud, A H M J; Barman, T; Hebb, L; Montalban, J; Maxted, P F L; Queloz, D; Deleuil, M; Magain, P

    2009-01-01

    We present VLT eclipse photometry for the giant planet CoRoT-1b. We observed a transit in the R-band filter and an occultation in a narrow filter centered on 2.09 microns. Our analysis of this new photometry and published radial velocities, in combination with stellar-evolutionary modeling, leads to a planetary mass and radius of 1.07 (+0.13,-0.18) M_Jup and 1.45 (+0.07,-0.13) R_Jup, confirming the very low density previously deduced from CoRoT photometry. The large occultation depth that we measure at 2.09 microns (0.278 (+0.043,-0.066) %) is consistent with thermal emission and is better reproduced by an atmospheric model with no redistribution of the absorbed stellar flux to the night side of the planet.

  15. Mid-IR observations of NGC 1068 with VLT/VISIR

    CERN Document Server

    Poncelet, A; Perrin, G; Sol, H; Lagage, P O

    2006-01-01

    We present a speckle analysis of the active galactic nucleus (AGN) inside the archetype Seyfert type 2 galaxy NGC 1068. This study is based on 12.8 microns images obtained with the burst mode of VISIR (the Very Large Telescope Imager and Spectrometer in the InfraRed). The interferometric processing allows to push the resolution far below the diffraction limit of a 8m telescope in the N-band and to trace two main contributions to the mid-IR flux inside the nucleus. It also allows to partially fill the lack of visibility points at low spatial frequencies. The confrontation with VLT/MIDI (the Mid-InfrareD Interferometer) data points helps to establish the link between dust in the vicinity of the central engine and inside the ionisation cone to get a multi-scale picture of mid-IR sources emitting in the nucleus of NGC 1068.

  16. The Space Missions WAXS/WFXT and SWIFT New Targets for the VLT

    CERN Document Server

    Chincarini, G L

    1999-01-01

    At OAB we were, during the year 1998, deeply involved in planning two important space missions for which very large ground based telescopes, VLT in particular, would play a very large and important role in the optical followup. The study of the first mission, Wide Angle X-ray Survey using a Wide Field X-ray Telescope, was coordinated by the Observatory of Brera, involved mainly Italian industries and resulted in a proposal to the Italian Space Agency under the Small Satellite Program. The second mission, SWIFT, has been coordinated and directed by the Goddard Space Flight Center and resulted in the submission of a proposal to NASA under the MIDEX program. The science goal of this mission is the detection and study of the Gamma-ray bursts.

  17. Direct exoplanet detection and characterization using the ANDROMEDA method: Performance on VLT/NaCo data

    CERN Document Server

    Cantalloube, F; Mugnier, L M; Milli, J; Absil, O; Gonzalez, C A Gomez; Chauvin, G; Beuzit, J -L; Cornia, A

    2015-01-01

    Context. The direct detection of exoplanets with high-contrast imaging requires advanced data processing methods to disentangle potential planetary signals from bright quasi-static speckles. Among them, angular differential imaging (ADI) permits potential planetary signals with a known rotation rate to be separated from instrumental speckles that are either statics or slowly variable. The method presented in this paper, called ANDROMEDA for ANgular Differential OptiMal Exoplanet Detection Algorithm is based on a maximum likelihood approach to ADI and is used to estimate the position and the flux of any point source present in the field of view. Aims. In order to optimize and experimentally validate this previously proposed method, we applied ANDROMEDA to real VLT/NaCo data. In addition to its pure detection capability, we investigated the possibility of defining simple and efficient criteria for automatic point source extraction able to support the processing of large surveys. Methods. To assess the performan...

  18. The binarity status of stars with and without planets Probed with vlt/naco

    Directory of Open Access Journals (Sweden)

    S. Udry

    2004-01-01

    Full Text Available Las propiedades de los planetas en orbita alrededor de una componente de una estrella binaria o m ultiple son distintas a las de los planetas de las estrellas aisladas (Udry et al., 2004. Describimos un sondeo con la optica adaptativa VLT/NACO que intenta estudiar el efecto de la duplicidad estelar en la formaci on y evoluci on de los planetas, comparando la estad stica de las compa~neras d ebiles en muestras de estrellas con y sin planetas, seleccionadas en forma similar. Los resultados nos permitir an discriminar entre los modelos para la formaci on de planetas (acreci on o inestabilidad del disco. Los resultados preliminares son muy interesantes: el 20 7% de las estrellas \\sencillas" tienen compa~neras dentro de 1000, mientras que s olo el 3 3% de compa~neras equivalentes se encuentran cerca de las estrellas que albergan.

  19. Deep census of variable stars in a VLT/VIMOS field in Carina

    CERN Document Server

    Pietrukowicz, P; Fernández, J M; Pietrzynski, G; Ruiz, M T; Gieren, W; Diaz, R F; Zoccali, M; Hempel, M

    2009-01-01

    We have searched for variable stars in deep V-band images of a field towards the Galactic plane in Carina. The images were taken with VIMOS instrument at ESO VLT during 4 contiguous nights in April 2005. We detected 348 variables among 50897 stars in the magnitude range between V=15.4 and V=24.5 mag. Upon detection, we classified the variables by direct eye inspection of their light curves. All variable objects but 9 OGLE transits in the field are new discoveries. We provide a complete catalog of all variables which includes eclipsing/ellipsoidal binaries, miscellaneous pulsators (mostly delta Scuti-type variables), stars with flares and other (irregular and likely long-period) variables. Only two of the stars in our sample are known to host planets. Our result give some implications for future large variability surveys.

  20. Close Companions to Nearby Young Stars from Adaptive Optics Imaging on VLT and Keck

    Science.gov (United States)

    Haisch, Karl E.; Jayawardhana, Ray; Brandeker, Alexis; Mardones, Diego

    We report the results of VLT and Keck adaptive optics surveys of known members of the η Chamaeleontis, MBM 12, and TW Hydrae (TWA) associations to search for close companions. The multiplicity statistics of η Cha, MBM 12, and TWA are quite high compared with other clusters and associations, although our errors are large due to small number statistics. We have resolved S18 in MBM 12 and RECX 9 in η Cha into triples for the first time. The tight binary TWA 5Aab in the TWA offers the prospect of measuring the dynamical masses of both components as well as an independent distance to the system within a few years. The AO detection of the close companion to the nearby young star χ1 Orionis, previously inferred from radial velocity and astrometric observations, has already made it possible to derive the dynamical masses of that system without any astrophysical assumption.

  1. Close Companions to Nearby Young Stars from Adaptive Optics Imaging on VLT and Keck

    CERN Document Server

    Haisch, K E; Brandeker, A; Mardones, D; Jr., Karl E. Haisch; Jayawardhana, Ray; Brandeker, Alexis; Mardones, Diego

    2003-01-01

    We report the results of VLT and Keck adaptive optics surveys of known members of the Eta Chamaeleontis, MBM 12, and TW Hydrae (TWA) associations to search for close companions. The multiplicity statistics of Eta Cha, MBM 12, and TWA are quite high compared with other clusters and associations, although our errors are large due to small number statistics. We have resolved S18 in MBM 12 and RECX 9 in Eta Cha into triples for the first time. The tight binary TWA 5Aab in the TWA offers the prospect of measuring the dynamical masses of both components as well as an independent distance to the system within a few years. The AO detection of the close companion to the nearby young star Chi^1 Orionis, previously inferred from radial velocity and astrometric observations, has already made it possible to derive the dynamical masses of that system without any astrophysical assumption.

  2. Reactor Neutrino Spectra

    CERN Document Server

    Hayes, A C

    2016-01-01

    We present a review of the antineutrino spectra emitted from reactors. Knowledge of these and their associated uncertainties are crucial for neutrino oscillation studies. The spectra used to-date have been determined by either conversion of measured electron spectra to antineutrino spectra or by summing over all of the thousands of transitions that makeup the spectra using modern databases as input. The uncertainties in the subdominant corrections to beta-decay plague both methods, and we provide estimates of these uncertainties. Improving on current knowledge of the antineutrino spectra from reactors will require new experiments. Such experiments would also address the so-called reactor neutrino anomaly and the possible origin of the shoulder observed in the antineutrino spectra measured in recent high-statistics reactor neutrino experiments.

  3. XQ-100: A legacy survey of one hundred 3.5 ≲ z ≲ 4.5 quasars observed with VLT/X-shooter

    Science.gov (United States)

    López, S.; D'Odorico, V.; Ellison, S. L.; Becker, G. D.; Christensen, L.; Cupani, G.; Denney, K. D.; Pâris, I.; Worseck, G.; Berg, T. A. M.; Cristiani, S.; Dessauges-Zavadsky, M.; Haehnelt, M.; Hamann, F.; Hennawi, J.; Iršič, V.; Kim, T.-S.; López, P.; Lund Saust, R.; Ménard, B.; Perrotta, S.; Prochaska, J. X.; Sánchez-Ramírez, R.; Vestergaard, M.; Viel, M.; Wisotzki, L.

    2016-10-01

    We describe the execution and data reduction of the European Southern Observatory Large Programme "Quasars and their absorption lines: a legacy survey of the high-redshift Universe with VLT/X-shooter" (hereafter "XQ-100"). XQ-100 has produced and made publicly available a homogeneous and high-quality sample of echelle spectra of 100 quasars (QSOs) at redshifts z ≃ 3.5-4.5 observed with full spectral coverage from 315 to 2500 nm at a resolving power ranging from R ~ 4000 to 7000, depending on wavelength. The median signal-to-noise ratios are 33, 25 and 43, as measured at rest-frame wavelengths 1700, 3000 and 3600 Å, respectively. This paper provides future users of XQ-100 data with the basic statistics of the survey, along with details of target selection, data acquisition and data reduction. The paper accompanies the public release of all data products, including 100 reduced spectra. XQ-100 is the largest spectroscopic survey to date of high-redshift QSOs with simultaneous rest-frame UV/optical coverage, and as such enables a wide range of extragalactic research, from cosmology and galaxy evolution to AGN astrophysics. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 189.A-0424.The XQ-100 raw data and the XQ-100 Science Data Products can be found at http://archive.eso.org/eso/eso_archive_main.html and http://archive.eso.org/wdb/wdb/adp/phase3_main/form, respectively.

  4. HST/WFC3 observations of Uranus' 2014 storm clouds and comparison with VLT/SINFONI and IRTF/Spex observations

    Science.gov (United States)

    Irwin, Patrick G. J.; Wong, Michael H.; Simon, Amy A.; Orton, G. S.; Toledo, Daniel

    2017-05-01

    In November 2014 Uranus was observed with the Wide Field Camera 3 (WFC3) instrument of the Hubble Space Telescope as part of the Hubble 2020: Outer Planet Atmospheres Legacy program, OPAL. OPAL annually maps Jupiter, Uranus and Neptune (and will also map Saturn from 2018) in several visible/near-infrared wavelength filters. The Uranus 2014 OPAL observations were made on the 8/9th November at a time when a huge cloud complex, first observed by de Pater et al. (2015) and subsequently tracked by professional and amateur astronomers (Sayanagi et al., 2016), was present at 30-40°N. We imaged the entire visible atmosphere, including the storm system, in seven filters spanning 467-924 nm, capturing variations in the coloration of Uranus' clouds and also vertical distribution due to wavelength dependent changes in Rayleigh scattering and methane absorption optical depth. Here we analyse these new HST observations with the NEMESIS radiative-transfer and retrieval code in multiple-scattering mode to determine the vertical cloud structure in and around the storm cloud system. The same storm system was also observed in the H-band (1.4-1.8 μm) with the SINFONI Integral Field Unit Spectrometer on the Very Large Telescope (VLT) on 31st October and 11th November, reported by Irwin et al. (2016, 10.1016/j.icarus.2015.09.010). To constrain better the cloud particle sizes and scattering properties over a wide wavelength range we also conducted a limb-darkening analysis of the background cloud structure in the 30-40°N latitude band by simultaneously fitting: a) these HST/OPAL observations at a range of zenith angles; b) the VLT/SINFONI observations at a range of zenith angles; and c) IRTF/SpeX observations of this latitude band made in 2009 at a single zenith angle of 23°, spanning the wavelength range 0.8-1.8 μm (Irwin et al., 2015, 10.1016/j.icarus.2014.12.020). We find that the HST observations, and the combined HST/VLT/IRTF observations at all locations are well modelled with

  5. Extração da catarata pela técnica de facoemulsificação em pacientes com uveíte Cataract extraction using the phacoemulsification technique in patients with uveitis

    Directory of Open Access Journals (Sweden)

    Cláudio de Lima Yamane

    2007-08-01

    Full Text Available OBJETIVO: Descrever os resultados da cirurgia de catarata pela técnica de facoemulsificação em pacientes com uveíte. MÉTODOS: Foi realizado estudo retrospectivo pela análise de prontuários de 189 pacientes (242 olhos com uveíte que foram submetidos a cirurgia de catarata pela técnica de facoemulsificação no Setor de Uveítes e Imunologia Ocular do Royal Victoria Hospital, McGill University Health Centre, Montreal, Quebec, Canadá. Os dados foram coletados em fichas protocoladas com informações sobre sexo, idade, classificação da uveíte, descrição cirúrgica e exames pré e pós-operatórios. Os exames pré e pós-operatórios continham informações sobre a data do exame, a melhor acuidade visual corrigida, o exame biomicroscópico, a pressão intra-ocular, os procedimentos realizados e o tratamento em uso. RESULTADOS: A média de acompanhamento pós-operatório foi de 46,8 ± 31,2 meses. A média da acuidade visual pré-operatória encontrada foi de 20/100 e a média de acuidade visual pós-operatória encontrada foi de 20/40. Encontramos 145 olhos (59,5% com acuidade visual melhor ou igual a 20/40 e 26 olhos com piora da acuidade visual. A complicação per-operatória mais encontrada foi a ruptura de cápsula posterior com perda vítrea observada em 7 olhos (3% do total de olhos. A recorrência da uveíte foi a complicação pós-operatória mais freqüente, sendo observada em 73 olhos (30,16%. Outras complicações pós-operatórias observadas foram a atrofia iriana (28,51%, hipertensão intra-ocular (28,09%, membrana epirretiniana (26,44%, opacidade de cápsula posterior (19%, edema macular cistóide (13,63%, hipotonia ocular (12,80%, atrofia do disco óptico (8,67% e sinéquias posteriores (6,61%. CONCLUSÕES: A cirurgia de catarata pela técnica de facoemulsificação é considerada segura e eficaz em pacientes com uveíte. Observamos um bom prognóstico visual no período de acompanhamento pós-operatório, apesar da

  6. VizieR Online Data Catalog: Narrow absorption lines of lensed QSO J1029+2623 (Misawa+, 2016)

    Science.gov (United States)

    Misawa, T.; Saez, C.; Charlton, J. C.; Eracleous, M.; Chartas, G.; Bauer, F. E.; Inada, N.; Uchiyama, H.

    2016-08-01

    We acquired high-resolution spectra of the brightest two of the three lensed images of the quasar SDSS J1029+2623, A and B with V=18.72 and 18.67mags, with the VLT using the Ultraviolet and Visual Echelle Spectrograph (UVES) in queue mode (ESO program 092.B-0512(A)). The observations were performed from 2014 January 28 to February 26, which is ~4yrs after the first observation on 2010 February 10 (Misawa+ 2013AJ....145...48M), and ~2 months before the third observation on 2014 April 4 (Misawa+ 2014ApJ...794L..20M) with Subaru using the High Dispersion Spectrograph (HDS). The wavelength coverage is 3300-6600Å with R~33000. Log of observations: -------------------------------------------------------------- Target Obs. date Instrument R Ref -------------------------------------------------------------- SDSS J1029+2623 A 2010 Feb 10 Subaru/HDS 30000 1 SDSS J1029+2623 A 2014 Jan 28-Feb 3 VLT/UVES 33000 2 SDSS J1029+2623 A 2014 Apr 4 Subaru/HDS 36000 3 SDSS J1029+2623 B 2010 Feb 10 Subaru/HDS 30000 1 SDSS J1029+2623 B 2014 Feb 4-26 VLT/UVES 33000 2 SDSS J1029+2623 B 2014 Apr 4 Subaru/HDS 36000 3 -------------------------------------------------------------- Ref: 1 = Misawa et al. 2013AJ....145...48M, 2 = This paper, 3 = Misawa et al. 2014ApJ...794L..20M -------------------------------------------------------------- (1 data file).

  7. Nota biobibliográfica + poética + creaciones («Uves migratorias», «Fronteras del hambre», «Puntos de sutura», «Paisaje urbano 2», «El intruso» y «Mirada rota» + cuestionario (Victoria Pineda

    Directory of Open Access Journals (Sweden)

    Julián Alonso

    2014-03-01

    Full Text Available Nota biobibliográfica + poética + creaciones («Uves migratorias», «Fronteras del hambre», «Puntos de sutura», «Paisaje urbano 2», «El intruso» y «Mirada rota» + cuestionario (Victoria Pineda

  8. Intracluster light properties in the CLASH-VLT cluster MACS J1206.2-0847

    Science.gov (United States)

    Presotto, V.; Girardi, M.; Nonino, M.; Mercurio, A.; Grillo, C.; Rosati, P.; Biviano, A.; Annunziatella, M.; Balestra, I.; Cui, W.; Sartoris, B.; Lemze, D.; Ascaso, B.; Moustakas, J.; Ford, H.; Fritz, A.; Czoske, O.; Ettori, S.; Kuchner, U.; Lombardi, M.; Maier, C.; Medezinski, E.; Molino, A.; Scodeggio, M.; Strazzullo, V.; Tozzi, P.; Ziegler, B.; Bartelmann, M.; Benitez, N.; Bradley, L.; Brescia, M.; Broadhurst, T.; Coe, D.; Donahue, M.; Gobat, R.; Graves, G.; Kelson, D.; Koekemoer, A.; Melchior, P.; Meneghetti, M.; Merten, J.; Moustakas, L. A.; Munari, E.; Postman, M.; Regős, E.; Seitz, S.; Umetsu, K.; Zheng, W.; Zitrin, A.

    2014-05-01

    Aims: We aim constrain the assembly history of clusters by studying the intracluster light (ICL) properties, estimating its contribution to the fraction of baryons in stars, f∗, and understanding possible systematics or bias using different ICL detection techniques. Methods: We developed an automated method, GALtoICL, based on the software GALAPAGOS, to obtain a refined version of typical BCG+ICL maps. We applied this method to our test case MACS J1206.2-0847, a massive cluster located at z ~ 0.44, which is part of the CLASH sample. Using deep multiband Subaru images, we extracted the surface brightness (SB) profile of the BCG+ICL and studied the ICL morphology, color, and contribution to f∗ out to R500. We repeated the same analysis using a different definition of the ICL, SBlimit method, i.e., a SB cut-off level, to compare the results. Results: The most peculiar feature of the ICL in MACS1206 is its asymmetric radial distribution, with an excess in the SE direction and extending toward the second brightest cluster galaxy, which is a post starburst galaxy. This suggests an interaction between the BCG and this galaxy that dates back to τ ≤ 1.5 Gyr. The BCG+ICL stellar content is ~8% of M∗,500, and the (de-) projected baryon fraction in stars is f∗ = 0.0177(0.0116), in excellent agreement with recent results. The SBlimit method provides systematically higher ICL fractions and this effect is stronger at lower SB limits. This is due to the light from the outer envelopes of member galaxies that contaminate the ICL. Though more time consuming, the GALtoICL method provides safer ICL detections that are almost free of this contamination. This is one of the few ICL study at redshift z > 0.3. At completion, the CLASH/VLT program will allow us to extend this analysis to a statistically significant cluster sample spanning a wide redshift range: 0.2 ≲ z ≲ 0.6. Based on data collected at the NASJ Subaru telescope, at the ESO VLT (prog.ID 186.A-0798), and the

  9. The OmegaCAM 16K x 16K CCD detector system for the ESO VLT Survey Telescope (VST)

    NARCIS (Netherlands)

    Iwert, Olaf; Baade, D.; Balestra, A.; Baruffolo, A.; Bortolussi, A.; Christen, F.; Cumani, C.; Deiries, S.; Downing, M.; Geimer, C.; Hess, G.; Hess, J.; Kuijken, K.; Lizon, J.; Muschielok, B.; Nicklas, H.; Reiss, R.; Reyes, J.; Silber, A.; Thillerup, J.; Valentijn, E.; Dorn, David A.; Holland, Andrew D.

    2006-01-01

    A 16K x 16K, 1 degree x 1 degree field, detector system was developed by ESO for the OmegaCAM instrument for use on the purpose built ESO VLT Survey Telescope (VST). The focal plane consists of an 8 x 4 mosaic of 2K x 4K 15um pixel e2v CCDs and four 2K x 4K CCDs on the periphery for the opto-mechani

  10. Action spectra again?

    Science.gov (United States)

    Coohill, T P

    1991-11-01

    Action spectroscopy has a long history and is of central importance to photobiological studies. Action spectra were among the first assays to point to chlorophyll as the molecule most responsible for plant growth and to DNA as the genetic material. It is useful to construct action spectra early in the investigation of new areas of photobiological research in an attempt to determine the wavelength limits of the radiation region causing the studied response. But due to the severe absorption of ultraviolet (UV) radiation by biological samples, UV action spectra were first limited to small cells (bacteria and fungi). Advances in techniques (e.g. single cell culture) and analysis allowed accurate action spectra to be reported even for mammalian cells. But precise analytical action spectra are often difficult to obtain when large, pigmented, or groups of cells are investigated. Here some action spectra are limited in interpretation and merely supply a wavelength vs effect curve. When polychromatic sources are employed, the interpretation of action spectra is even more complex and formidable. But such polychromatic action spectra can be more directly related to ambient responses. Since precise action spectra usually require the completion of a relatively large number of careful experiments using somewhat sophisticated equipment over a range of at least six wavelengths, they are often not pursued. But they remain central to the elucidation of the effect being studied. The worldwide community has agreed that stratospheric ozone is depleting, with the possibility of a consequent rise in the amount of UV-B (290-320 nm) reaching the earth's surface. It is therefore essential that new action spectra be completed for UV-B effects on a large variety of responses of human, animal, and aquatic plant systems. Combining these action spectra with the known amounts of UV-B reaching the biosphere can give rise to solar UV effectiveness spectra that, in turn, can give rise to estimates

  11. Status and new operation modes of the versatile VLT/NaCo

    Science.gov (United States)

    Girard, Julien H. V.; Kasper, Markus; Quanz, Sascha P.; Kenworthy, Matthew A.; Rengaswamy, Sridharan; Schödel, Rainer; Gallenne, Alexandre; Gillessen, Stefan; Huerta, Nicolas; Kervella, Pierre; Kornweibel, Nick; Lenzen, Rainer; Mérand, Antoine; Montagnier, Guillaume; O'Neal, Jared; Zins, Gérard

    2010-07-01

    This paper aims at giving an update on the most versatile Adaptive Optics fed instrument to date, the well known and successful NACO*. Although NACO is only scheduled for about two more years† at the Very Large Telescope (VLT), it keeps on evolving with additional operation modes bringing original astronomical results. The high contrast imaging community uses it creatively as a test-bench for SPHERE‡ and other second generation planet imagers. A new visible wavefront sensor (WFS) optimized for Laser Guide Star (LGS) operations has been installed and tested, the cube mode is more and more required for frame selection on bright sources, a seeing enhancer mode (no tip/tilt correction) is now offered to provide full sky coverage and welcome all kind of extragalactic applications, etc. The Instrument Operations Team (IOT) and Paranal engineers are currently working hard at maintaining the instrument overall performances but also at improving them and offering new capabilities, providing the community with a well tuned and original instrument for the remaining time it is being used. The present contribution delivers a non-exhaustive overview of the new modes and experiments that have been carried out in the past months.

  12. VLT/SPHERE deep insight of NGC 3603's core: Segregation or confusion?

    CERN Document Server

    Khorrami, Z; Vakili, F; Lagadec, E; Langlois, M; Brandner, W; Chesneau, O; Meyer, M R; Carbillet, M; Abe, L; Mouillet, D; Beuzit, JL; Boccaletti, A; Perrot, C; Thalmann, C; Schmid, H -M; Pavlov, A; Costille, A; Dohlen, K; Mignant, D Le; Petit, C; Sauvage, J F

    2016-01-01

    We present new near-infrared photometric measurements of the core of the young massive cluster NGC 3603 obtained with extreme adaptive optics. The data were obtained with the SPHERE instrument mounted on ESO Very Large Telescope, and cover three fields in the core of this cluster. We applied a correction for the effect of extinction to our data obtained in the J and K broadband filters and estimated the mass of detected sources inside the field of view of SPHERE/IRDIS, which is 13.5"x13.5". We derived the mass function (MF) slope for each spectral band and field. The MF slope in the core is unusual compared to previous results based on Hubble space telescope (HST) and very large telescope (VLT) observations. The average slope in the core is estimated as -1.06^{+0.26}_{-0.26} for the main sequence stars with 3.5 Msun < M < 120 Msun.Thanks to the SPHERE extreme adaptive optics, 814 low-mass stars were detected to estimate the MF slope for the pre-main sequence stars with 0.6 Msun< M < 3.5 Msun , Gam...

  13. VLT/FLAMES spectroscopy of Red Giant Branch stars in the Carina dwarf spheroidal galaxy

    CERN Document Server

    Lemasle, B; Tolstoy, E; Venn, K A; Shetrone, M D; Irwin, M J; de Boer, T J L; Starkenburg, E; Salvadori, S

    2011-01-01

    The ages of individual Red Giant Branch stars (RGB) can range from 1 Gyr old to the age of the Universe, and it is believed that the abundances of most chemical elements in their photospheres remain unchanged with time (those that are not affected by the 1st dredge-up). This means that they trace the ISM in the galaxy at the time the star formed, and hence the chemical enrichment history of the galaxy. CMD analysis has shown the Carina dwarf spheroidal (dSph) to have had an unusually episodic star formation history (SFH) which is expected to be reflected in the abundances of different chemical elements. We use the VLT-FLAMES spectrograph in HR mode (R~20000) to measure the abundances of several chemical elements in a sample of 35 RGB stars in Carina. We also combine these abundances with photometry to derive age estimates for these stars. This allows us to determine which of two distinct star formation (SF) episodes the stars in our sample belong to, and thus to define the relationship between SF and chemical...

  14. The VLT LBG Redshift Survey - IV. Gas and galaxies at z~3 in observations and simulations

    CERN Document Server

    Tummuangpak, P; Bielby, R; Crighton, N H M; Francke, H; Infante, L; Theuns, T

    2013-01-01

    We use observations and simulations to study the relationship between star-forming galaxies and the IGM at z~3. We use redshift data taken from the VLT LBG Redshift Survey (VLRS) and Keck surveys in fields centred on bright background QSOs, whilst the simulated data is taken from GIMIC. In the simulations, we find that the dominant peculiar velocities are in the form of large-scale coherent motions of gas and galaxies. Gravitational infall of galaxies towards each other is also seen, consistent with linear theory. Peculiar velocity pairs with separations smaller than 1Mpc have a smaller dispersion and better explain the simulated z-space correlations. Lyman-alpha auto- and cross-correlations in the simulations appear to show smaller infall than implied by the expected beta_Lyman-alpha ~ 1.3. Galaxy-wide outflows implemented in the simulations may contribute to this effect. When velocity errors are taken into account, the LBG correlation function prefers the high clustering amplitude shown by higher mass galax...

  15. The VLT LBG Redshift Survey - V. Characterising the z = 3.1 Lyman Alpha Emitter Population

    CERN Document Server

    Bielby, R M; Shanks, T; Francke, H; Crighton, N H M; Bañados, E; González-López, Jorge; Infante, L; Orsi, A

    2016-01-01

    We present a survey of Ly$\\alpha$ emitting galaxies in the fields of the VLT LBG Redshift Survey, incorporating the analysis of narrow band number counts, the rest frame UV luminosity function and the two-point correlation function of Ly$\\alpha$ emitters at $z\\approx3.1$. Our photometric sample consists of 750 LAE candidates, over an area of 1.07 deg$^2$, with estimated equivalent widths of $\\gtrsim65$ \\AA, from 5 fields based on deep Subaru Suprime-Cam imaging data. Added to this we have obtained spectroscopic follow-up observations, which successfully detected Ly$\\alpha$ emission in 35 galaxies. Based on the spectroscopic results, we refined our photometric selection constraints, with the resulting sample having a success rate of $78\\pm18\\%$. We calculate the narrow band number counts for our photometric sample and find these to be consistent with previous studies of LAEs at this redshift. We find the $R$-band continuum luminosity function to be $\\sim10\\times$ lower than the equivalent luminosity function o...

  16. VLT Suzaku observations of the Fermi pulsar PSR J1028-5819

    CERN Document Server

    Mignani, R P; Esposito, P; De Luca, A; Marelli, M; Oates, S R; Saz-Parkinson, P

    2012-01-01

    We used optical images taken with the Very Large Telescope (VLT) in the B and V bands to search for the optical counterpart of PSR J1028-5819 or constrain its optical brightness. At the same time, we used an archival Suzaku observation to confirm the preliminary identification of the pulsar's X-ray counterpart obtained by Swift. Due to the large uncertainty on the pulsar's radio position and the presence of a bright (V = 13.2) early F-type star at < 4", we could not detect its counterpart down to flux limits of B~25.4 and V ~25.3, the deepest obtained so far for PSR J1028-5819. From the Suzaku observations, we found that the X-ray spectrum of the pulsar's candidate counterpart is best-fit by a power-law with spectral index 1.7 +/- 0.2 and an absorption column density NH < 10^21 cm-2, which would support the proposed X-ray identification. Moreover, we found possible evidence for the presence of diffuse emission around the pulsar. If real, and associated with a pulsar wind nebula (PWN), its surface bright...

  17. Discovery of a z = 6.17 galaxy from CFHT and VLT observations

    CERN Document Server

    Cuby, J G; McCracken, H; Cuillandre, J C; Magnier, E; Meneux, B

    2003-01-01

    We report the discovery of a galaxy at a redshift z = 6.17 identified from deep narrow band imaging and spectroscopic follow-up in one of the CFHT-VIRMOS deep survey fields at 0226-04. In addition to the existing deep BVRI images of this field, we obtained a very deep narrow band image at 920 nm with the aim of detecting Ly alpha emission at redshift ~ 6.5. Spectroscopic follow-up of some of the candidates selected on the basis of their excess flux in the NB920 filter was performed at the VLT-UT4 with the FORS2 instrument. For one object a strong and asymmetric emission line associated with a strong break in continuum emission is identified as Ly alpha at z = 6.17. This galaxy was selected from its continuum emission in the 920 nm filter rather than for its Ly alpha emission, in effect performing a Lyman Break detection at z = 6.17. We estimate a star formation rate of ~ 10 M/yr for this object, with a velocity dispersion \\~ 400 km/s. Similarly to other objects at redshifts ~ 5--6, this galaxy presents the ch...

  18. VLT/FLAMES spectroscopy of red giant branch stars in the Fornax dwarf spheroidal galaxy

    CERN Document Server

    Lemasle, B; Hill, V; Tolstoy, E; Irwin, M; Jablonka, P; Venn, K; Battaglia, G; Starkenburg, E; Shetrone, M; Letarte, B; Francois, P; Helmi, A; Primas, F; Kaufer, A; Szeifert, T

    2014-01-01

    Fornax is one of the most massive dwarf spheroidal galaxies in the Local Group. The Fornax field star population is dominated by intermediate age stars but star formation was going on over almost its entire history. It has been proposed that Fornax experienced a minor merger event. Despite recent progress, only the high metallicity end of Fornax field stars ([Fe/H]>-1.2 dex) has been sampled in larger number via high resolution spectroscopy. We want to better understand the full chemical evolution of this galaxy by better sampling the whole metallicity range, including more metal poor stars. We use the VLT-FLAMES multi-fibre spectrograph in high-resolution mode to determine the abundances of several alpha, iron-peak and neutron-capture elements in a sample of 47 individual Red Giant Branch stars in the Fornax dwarf spheroidal galaxy. We combine these abundances with accurate age estimates derived from the age probability distribution from the colour-magnitude diagram of Fornax. Similar to other dwarf spheroid...

  19. VLT/MUSE discovers a jet from the evolved B[e] star MWC 137

    CERN Document Server

    Mehner, A; Groh, J H; Oudmaijer, R D; Baade, D; Rivinius, T; Selman, F; Boffin, H M J; Martayan, C

    2016-01-01

    Not all stars exhibiting the optical spectral characteristics of B[e] stars share the same evolutionary stage. The Galactic B[e] star MWC 137 is a prime example of an object with uncertain classification, with previous work suggesting pre- and post-main sequence classification. Our goal is to settle this debate and provide reliable evolutionary classification. Integral field spectrograph observations with VLT MUSE of the cluster SH 2-266 are used to analyze the nature of MWC 137. A collimated outflow is discovered that is geometrically centered on MWC 137. The central position of MWC 137 in the cluster SH 2-266 within the larger nebula suggests strongly that it is a member of this cluster and that it is both at the origin of the nebula and the newly discovered jet. Comparison of the color-magnitude diagram of the brightest cluster stars with stellar evolutionary models results in a distance of about 5.2$\\pm$1.4 kpc. We estimate that the cluster is at least 3 Myr old. The jet extends over 66" (1.7 pc) projecte...

  20. VLT Phase Resolved Optical Spectroscopy of the Ultra-Compact Binary HM Cnc

    CERN Document Server

    Mason, Elena; Dall'Osso, S; Stella, L; Munari, U; Marconi, G; O'Brian, K; Covino, S; Fugazza, D

    2010-01-01

    A 321.5 s modulation was discovered in 1999 in the X-ray light curve of HM Cnc. In 2001 and 2002, optical photometric and spectroscopic observations revealed that HM Cnc is a very blue object with no intrinsic absorptions but broad (FWHM 1500 km s^-1) low equivalent width emission lines (EW 1-6A), which were first identified with the HeII Pickering series. The combination of X-ray and optical observations pictures HM Cnc as a double degenerate binary hosting two white dwarfs, and possibly being the shortest orbital period binary discovered so far. The present work is aimed at studying the orbital motion of the two components by following the variations of the shape, centroid and intensity of the emission lines through the orbit. In February 2007, we carried out the first phase resolved optical spectroscopic study with the VLT/FORS2 in the High Time Resolution (HIT) mode, yielding five phase bins in the 321 s modulation. Despite the low SNR, the data show that the intensity of the three most prominent emission...

  1. The VLT-FLAMES Tarantula Survey XXI. Stellar spin rates of O-type spectroscopic binaries

    CERN Document Server

    Ramírez-Agudelo, O H; de Mink, S E; Hénault-Brunet, V; de Koter, A; Langer, N; Tramper, F; Gräfener, G; Evans, C J; Vink, J S; Dufton, P L; Taylor, W D

    2015-01-01

    The initial distribution of spin rates of massive stars is a fingerprint of their elusive formation process. It also sets a key initial condition for stellar evolution and is thus an important ingredient in stellar population synthesis. So far, most studies have focused on single stars. Most O stars are however found in multiple systems. By establishing the spin-rate distribution of a sizeable sample of O-type spectroscopic binaries and by comparing the distributions of binary sub-populations with one another as well as with that of presumed single stars in the same region, we aim to constrain the initial spin distribution of O stars in binaries, and to identify signatures of the physical mechanisms that affect the evolution of the massive stars spin rates. We use ground-based optical spectroscopy obtained in the framework of the VLT-FLAMES Tarantula Survey (VFTS) to establish the projected equatorial rotational velocities (\\vrot) for components of 114 spectroscopic binaries in 30 Doradus. The \\vrot\\ values a...

  2. Upper limits for mass and radius of objects around Proxima Cen from SPHERE/VLT

    Science.gov (United States)

    Mesa, D.; Zurlo, A.; Milli, J.; Gratton, R.; Desidera, S.; Langlois, M.; Vigan, A.; Bonavita, M.; Antichi, J.; Avenhaus, H.; Baruffolo, A.; Biller, B.; Boccaletti, A.; Bruno, P.; Cascone, E.; Chauvin, G.; Claudi, R. U.; De Caprio, V.; Fantinel, D.; Farisato, G.; Girard, J.; Giro, E.; Hagelberg, J.; Incorvaia, S.; Janson, M.; Kral, Q.; Lagadec, E.; Lagrange, A.-M.; Lessio, L.; Meyer, M.; Peretti, S.; Perrot, C.; Salasnich, B.; Schlieder, J.; Schmid, H.-M.; Scuderi, S.; Sissa, E.; Thalmann, C.; Turatto, M.

    2017-03-01

    The recent discovery of an earth-like planet around Proxima Centauri has drawn much attention to this star and its environment. We performed a series of observations of Proxima Centauri using Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE), the planet-finder instrument installed at the European Southern Observatory (ESO) Very Large Telescope (VLT) UT3, using its near-infrared modules, InfraRed Dual-band Imager and Spectrograph (IRDIS) and IFS. No planet was detected directly, but we set upper limits on the mass up to 7 au by exploiting the AMES-COND models. Our IFS observations reveal that no planet more massive than ∼6-7 MJup can be present within 1 au. The dual-band imaging camera IRDIS also enables us to probe larger separations than other techniques such as radial velocity or astrometry. We obtained mass limits of the order of 4 MJup at separations of 2 au or larger, representing the most stringent mass limits at separations larger than 5 au available at the moment. We also made an attempt to estimate the radius of possible planets around Proxima using the reflected light. Since the residual noise for the observations is dominated by photon noise and thermal background, longer exposures in good observing conditions could improve the achievable contrast limit further.

  3. VLT/VIMOS integral field spectroscopy of luminous and ultraluminous infrared galaxies: 2D kinematic properties

    CERN Document Server

    Bellocchi, Enrica; Colina, Luis; Miralles-Caballero, Daniel

    2013-01-01

    We present and discuss the 2D kinematic properties of the ionized gas (Halpha) in a sample of 38 local (ultra) luminous infrared galaxies [(U)LIRGs] (31 LIRGs and 7 ULIRGs) observed with VIMOS at the VLT using integral field spectroscopy. This sample covers well the less studied LIRG luminosity range and includes isolated disks, interacting systems, and mergers. The majority of the galaxies have two main kinematically distinct components. One component (i.e., narrow or systemic) extends over the whole line-emitting region and is characterized by small to intermediate velocity dispersions (i.e., sigma from 30 to 160 km s^-1). It traces the overall velocity field. The second component (broad) has in general a larger velocity dispersion (up to 320 km s^-1), mainly found in the inner regions and generally blueshifted with respect to the systemic component. Most of the objects (76%) are dominated by rotation, more relevant in LIRGs than in ULIRGs. Isolated disks, interacting galaxies, and merging systems define a ...

  4. Design of a Full-Stokes Polarimeter for VLT/X-shooter

    CERN Document Server

    Snik, Frans; Navarro, Ramon; Groot, Paul; Kaper, Lex; de Wijn, Alfred

    2012-01-01

    X-shooter is one of the most popular instruments at the VLT, offering instantaneous spectroscopy from 300 to 2500 nm. We present the design of a single polarimetric unit at the polarization-free Cassegrain focus that serves all three spectrograph arms of X-shooter. It consists of a calcite Savart plate as a polarizing beam-splitter and a rotatable crystal retarder stack as a "polychromatic modulator". Since even "superachromatic" wave plates have a wavelength range that is too limited for X-shooter, this novel modulator is designed to offer close-to-optimal polarimetric efficiencies for all Stokes parameters at all wavelengths. We analyze the modulator design in terms of its polarimetric performance, its temperature sensitivity, and its polarized fringes. Furthermore, we present the optical design of the polarimetric unit. The X-shooter polarimeter will furnish a myriad of science cases: from measuring stellar magnetic fields (e.g., Ap stars, white dwarfs, massive stars) to determining asymmetric structures a...

  5. Testing intermediate-age stellar evolution models with VLT photometry of LMC clusters. I. The data

    CERN Document Server

    Gallart, C; Bertelli, G; Chiosi, C; Demarque, P; Girardi, L; Nasi, E; Woo, J H; Yi, S

    2003-01-01

    This is the first of a series of three papers devoted to the calibration of a few parameters of crucial importance in the modeling of the evolution of intermediate-mass stars, with special attention to the amount of convective core overshoot. To this end we acquired deep V and R photometry for three globular clusters of the Large Magellanic Cloud (LMC), namely NGC 2173, SL 556 and NGC 2155, in the age interval 1-3 Gyr. In this first paper, we describe the aim of the project, the VLT observations and data reduction, and we make preliminary comparisons of the color-magnitude diagrams with both Padova and Yonsei-Yale isochrones. Two following papers in this series present the results of a detailed analysis of these data, independently carried out by members of the Yale and Padova stellar evolution groups. This allows us to compare both sets of models and discuss their main differences, as well as the systematic effects that they would have to the determination of the ages and metallicities of intermediate-age si...

  6. A nearby GRB host galaxy: VLT/X-shooter observations of HG 031203

    CERN Document Server

    Guseva, N G; Fricke, K J; Henkel, C; 10.1051/0004-6361/201116765

    2011-01-01

    (abridged) Long-duration gamma-ray bursts (LGRBs) occur in galaxies of generally low metallicity. We aim at a spectroscopic analysis of HG 031203, the host galaxy of a LRGB burst, to obtain its properties. Based on VLT/X-shooter spectroscopic observations in the wavelength range 3200-24000A, we use standard direct methods to evaluate physical conditions and element abundances. The resolving power of the instrument also allowed us to trace the kinematics of the ionised gas. We derive an interstellar oxygen abundance of 12+logO/H=8.20+/-0.03. The observed fluxes of hydrogen lines correspond to the theoretical recombination values after correction for extinction with a single value C(Hbeta)=1.67. We produce the CLOUDY photoionisation HII region model that reproduces observed emission-line fluxes of different ions in the optical range. This model also predicts emission-line fluxes in the near-infrared (NIR) and mid-infrared (MIR) ranges that agree well with the observed ones. This implies that the star-forming re...

  7. CLASH-VLT: Testing the Nature of Gravity with Galaxy Cluster Mass Profiles

    CERN Document Server

    Pizzuti, L; Borgani, S; Amendola, L; Umetsu, K; Biviano, A; Girardi, M; Rosati, P; Balestra, I; Caminha, G B; Frye, B; Koekemoer, A; Grillo, C; Lombardi, M; Mercurio, A; Nonino, M

    2016-01-01

    We use high-precision kinematic and lensing measurements of the total mass profile of the dynamically relaxed galaxy cluster MACS J1206.2-0847 at $z=0.44$ to estimate the value of the ratio $\\eta=\\Psi/\\Phi$ between the two scalar potentials in the linear perturbed Friedmann-Lemaitre-Robertson-Walker metric.[...] Complementary kinematic and lensing mass profiles were derived from exhaustive analyses using the data from the Cluster Lensing And Supernova survey with Hubble (CLASH) and the spectroscopic follow-up with the Very Large Telescope (CLASH-VLT). Whereas the kinematic mass profile tracks only the time-time part of the perturbed metric (i.e. only $\\Phi$), the lensing mass profile reflects the contribution of both time-time and space-space components (i.e. the sum $\\Phi+\\Psi$). We thus express $\\eta$ as a function of the mass profiles and perform our analysis over the radial range $0.5\\,Mpc\\le r\\le r_{200}=1.96\\,Mpc$. Using a spherical Navarro-Frenk-White mass profile, which well fits the data, we obtain $...

  8. The VLT-FLAMES Tarantula Survey XIV. The O-Type Stellar Content of 30 Doradus

    CERN Document Server

    Walborn, N R; Simon-Diaz, S; Apellaniz, J Maiz; Taylor, W D; Evans, C J; Markova, N; Lennon, D J; de Koter, A

    2014-01-01

    Detailed spectral classifications are presented for 352 O-B0 stars in the VLT-FLAMES Tarantula Survey, of which 213 O-type are of sufficient quality for further morphological analysis. Among them, six subcategories of special interest are distinguished. (1) Several new examples of the earliest spectral types O2-O3 have been found. (2) A group of extremely rapidly rotating main-sequence objects has been isolated, including the largest $v\\sin i$ values known, the spatial and radial-velocity distributions of which suggest ejection from the two principal ionizing clusters. (3) Several new examples of the evolved, rapidly rotating Onfp class show similar evidence. (4) No fewer than 48 members of the Vz category, hypothesized to be on or near the ZAMS, are found in this sample; in contrast to the rapid rotators, they are strongly concentrated to the ionizing clusters, supporting their interpretation as very young objects, as do their relatively faint absolute magnitudes. (5) A surprisingly large fraction of the mai...

  9. The VLT-FLAMES Tarantula Survey XII. Rotational velocities of the single O-type stars

    CERN Document Server

    Ramírez-Agudelo, O H; Sana, H; de Koter, A; Sabín-Sanjulían, C; de Mink, S E; Dufton, P L; Gräfener, G; Evans, C J; Herrero, A; Langer, N; Lennon, D J; Apellániz, J Maíz; Markova, N; Najarro, F; Puls, J; Taylor, W D; Vink, J S

    2013-01-01

    Aims. Using ground based multi-object optical spectroscopy obtained in the framework of the VLT-FLAMES Tarantula Survey (VFTS), we aim to establish the (projected) rotational velocity distribution for a sample of 216 presumably single O-type stars in 30 Doradus (30 Dor). Methods. We measured projected rotational velocities, \\vrot, by means of a Fourier transform method and a profile fitting method applied on a set of isolated spectral lines. We also used an iterative deconvolution procedure to infer the probability density, $\\rm{P(\\veq)}$, of the equatorial rotational velocity, \\veq. Results. The distribution of \\vrot\\ shows a two-component structure: a peak around 80 \\kms\\ and a high-velocity tail extending up to $\\sim$600 \\kms. This structure is also present in the inferred distribution $\\rm{P(\\veq)}$ with around 80% of the sample having 0 $<$ \\veq\\, $\\leq\\, 300$ \\kms\\ and the other 20% distributed in the high-velocity region. Conclusions. Most of the stars in our sample rotate with a rate less than 20%\\...

  10. The VLT-FLAMES Tarantula Survey I: Introduction and observational overview

    CERN Document Server

    Evans, C J; Henault-Brunet, V; Sana, H; de Koter, A; Simon-Diaz, S; Carraro, G; Bagnoli, T; Bastian, N; Bestenlehner, J M; Bonanos, A Z; Bressert, E; Brott, I; Campbell, M A; Cantiello, M; Clark, J S; Costa, E; Crowther, P A; de Mink, S E; Doran, E; Dufton, P L; Dunstall, P R; Friedrich, K; Garcia, M; Gieles, M; Graefener, G; Herrero, A; Howarth, I D; Izzard, R G; Langer, N; Lennon, D J; Apellaniz, J Maiz; Markova, N; Najarro, F; Puls, J; Ramirez, O H; Sabin, C; Smartt, S J; Stroud, V E; van Loon, J Th; Vink, J S; Walborn, N R

    2011-01-01

    The VLT-FLAMES Tarantula Survey (VFTS) is an ESO Large Programme that has obtained multi-epoch optical spectroscopy of over 800 massive stars in the 30 Doradus region of the Large Magellanic Cloud (LMC). Here we introduce our scientific motivations and give an overview of the survey targets, including optical and near-infrared photometry and comprehensive details of the data reduction. One of the principal objectives was to detect massive binary systems via variations in their radial velocities, thus shaping the multi-epoch observing strategy. Spectral classifications are given for the massive emission-line stars observed by the survey, including the discovery of a new Wolf-Rayet star (VFTS 682, classified as WN5h), 2' to the northeast of R136. To illustrate the diversity of objects encompassed by the survey, we investigate the spectral properties of sixteen targets identified by Gruendl & Chu from Spitzer photometry as candidate young stellar objects or stars with notable mid-infrared excesses. Detailed ...

  11. The VLT-FLAMES Tarantula Survey II: R139 revealed as a massive binary system

    CERN Document Server

    Taylor, W D; Sana, H; Walborn, N R; de Mink, S E; Stroud, V E; Alvarez-Candal, A; Barbá, R H; Bestenlehner, J M; Bonanos, A Z; Brott, I; Crowther, P A; de Koter, A; Friedrich, K; Gräfener, G; Hénault-Brunet, V; Herrero, A; Kaper, L; Langer, N; Lennon, D J; Apellániz, J Maíz; Markova, N; Morrell, N; Monaco, L; Vink, J S

    2011-01-01

    We report the discovery that R139 in 30 Doradus is a massive spectroscopic binary system. Multi-epoch optical spectroscopy of R139 was obtained as part of the VLT-FLAMES Tarantula Survey, revealing a double-lined system. The two components are of similar spectral types; the primary exhibits strong C III 4650 emission and is classified as an O6.5 Iafc supergiant, while the secondary is an O6 Iaf supergiant. The radial-velocity variations indicate a highly eccentric orbit with a period of 153.9 days. Photometry obtained with the Faulkes Telescope South shows no evidence for significant variability within an 18 month period. The orbital solution yields lower mass limits for the components of M1sin^3 i = 78 \\pm 8 Msun and M2sin^3 i = 66 \\pm 7 Msun. As R139 appears to be the most massive binary system known to contain two evolved Of supergiants, it will provide an excellent test for atmospheric and evolutionary models.

  12. The VLT-FLAMES Tarantula Survey XXII. Multiplicity properties of the B-type stars

    CERN Document Server

    Dunstall, P R; Sana, H; Evans, C J; Howarth, I D; Simón-Díaz, S; de Mink, S E; Langer, N; Apellániz, J Maíz; Taylor, W D

    2015-01-01

    We investigate the multiplicity properties of 408 B-type stars observed in the 30 Doradus region of the Large Magellanic Cloud with multi-epoch spectroscopy from the VLT-FLAMES Tarantula Survey (VFTS). We use a cross-correlation method to estimate relative radial velocities from the helium and metal absorption lines for each of our targets. Objects with significant radial-velocity variations (and with an amplitude larger than 16 km/s) are classified as spectroscopic binaries. We find an observed spectroscopic binary fraction (defined by periods of 0.1) for the B-type stars, f_B(obs) = 0.25 +/- 0.02, which appears constant across the field of view, except for the two older clusters (Hodge 301 and SL 639). These two clusters have significantly lower fractions of 0.08 +/- 0.08 and 0.10 +/- 0.09, respectively. Using synthetic populations and a model of our observed epochs and their potential biases, we constrain the intrinsic multiplicity properties of the dwarf and giant (i.e. relatively unevolved) B-type stars ...

  13. A Deep Optical Luminosity Function of NGC 6712 with the VLT Evidence for Severe Tidal Disruption

    CERN Document Server

    De Marchi, G; Paresce, F; Pulonen, L E; Marchi, Guido De; Leibundgut, Bruno; Paresce, Francesco; Pulone, Luigi

    1999-01-01

    The VLT on Cerro Paranal was used to observe four fields located at 2.3' from the center of the Galactic globular cluster NGC 6712 in the V and R bands. The resulting color-magnitude diagram shows a well defined main sequence reaching down to the 5 sigma detection limit at V~25, R~23.5 or approximately 4 mag below the main sequence turn-off, the deepest obtained so far on this cluster. This yields a main sequence luminosity function that peaks at M_R~4.5 and drops down to the 50% completeness limit at M_R~8.5. Transformation to a mass function via the latest mass-luminosity relation appropriate to this object indicates that the peak of the luminosity function corresponds to ~0.75 Msolar, a value significantly higher than the ~0.25 Msolar measured for most other clusters observed so far. Since this object, in its Galactic orbit, penetrates very deeply into the Galactic bulge with perigalactic distance of ~0.3 kpc, this result is the first strong evidence that tidal forces have stripped this cluster of a substa...

  14. VLT/ISAAC H-band spectroscopy of embedded massive YSOs

    CERN Document Server

    Kendall, T R; Yun, J L

    2003-01-01

    We have performed intermediate resolution (R = 5000), high signal-to-noise H-band spectroscopy of a small, initial sample of three massive embedded young stellar objects (YSOs), using VLT/ISAAC. The sample has been selected from sources characterised in previous literature as being likely of OB spectral type, to be unambiguously associated with bright (H < 14) single point sources in the 2MASS database, and to have no optical counterparts. Of the targets observed, one object shows a ~B3 spectrum, similar to a main sequence object of the same spectral type. A second object exhibits weak HeI and H emission, indicating an early-type source: we detect HeII absorption, which supports a previous indirect derivation of the spectral type as mid-O. The third object does not show absorption lines, so no spectral type can de derived. It does, however, exhibit a rich spectrum of strong, broad emission lines and is likely to be surrounded by dense circumstellar material and at a very early evolutionary stage. Our resul...

  15. A VLT/FORS2 spectroscopic survey of individual stars in a transforming dwarf galaxy

    CERN Document Server

    Battaglia, G; Rejkuba, M

    2016-01-01

    Understanding the properties of dwarf galaxies is important not only to put them in their proper cosmological context, but also to understand the formation and evolution of the most common type of galaxies. Dwarf galaxies are divided into two main classes, dwarf irregulars (dIrrs) and dwarf spheroidals (dSphs), which differ from each other mainly because the former are gas-rich objects currently forming stars, while the latter are gas-deficient with no on-going star formation. Transition types (dT) are thought to represent dIs in the process of losing their gas, and can therefore shed light into the possible process of dwarf irregulars (dIrrs) becoming gas-deficient, passively evolving galaxies. Here we present preliminary results from our wide-area VLT/FORS2 MXU spectroscopic survey of the Phoenix dT, from which we obtained line-of-sight velocities and metallicities from the nIR Ca II triplet lines for a large sample of individual Red Giant Branch stars.

  16. Design, fabrication, integration and commissioning of an upgraded guiding probe for the VLT unit telescope 4

    Science.gov (United States)

    Frank, Christoph; Hammersley, Peter; Buzzoni, Bernard; Manescau, Antonio; Arsenault, Robin; Madec, Pierre-Yves; Birkmann, Martin; Mueller, Michael; Salgado, Fernando; Guisard, Stephane; Kroedel, Matthias

    2014-07-01

    As part of the preparation for the arrival of the MUSE instrument to the VLT, it was required to adapt the hosting telescope (UT4) guide probe, to increase its back focal length. This is to allow enough space for the later deployment of the MUSE Adaptive Optics module GALACSI, in-between the telescope adapter rotator and the instrument itself. The UT guide probe is a critical component for the successful operation of the telescope, so its modification to increase the telescope's back focal length, while maintaining full compatibility with the existing operation model and other hardware, was rather demanding. The design, manufacture, assembly and test for the new supporting arm in the UT guiding probe is presented. It mixes the use of novel materials (HB-CESIC® for the mirrors substrates) and state of the art manufacturing techniques (3D printing mould production and rapid casting for the support structure), which allow producing easily a high performance subsystem. Characterization of the system prior delivery to the telescope, its integration in the UT and results after commissioning is presented. Its successful implementation has validated new manufacturing techniques that may prove very useful for future instruments development.

  17. A VLT/NACO Study of Star Formation in the Massive Embedded Cluster RCW 38

    CERN Document Server

    DeRose, K L; Gutermuth, R A; Wolk, S J; Megeath, S T; Alves, J; Nürnberger, D

    2009-01-01

    We present adaptive optics (AO) near-infrared (JHKs) observations of the deeply embedded massive cluster RCW 38 using NACO on the VLT. Narrowband AO observations centered at wavelengths of 1.28, 2.12, and 2.17 micron were also obtained. The area covered by these observations is about 0.5 pc square, centered on the O star RCW 38 IRS2. We use the JHKs colors to identify young stars with infrared excess. Through a detailed comparison to a nearby control field, we find that most of the 337 stars detected in all three infrared bands are cluster members (~317), with essentially no contamination due to background or foreground sources. Five sources have colors suggestive of deeply embedded protostars, while 53 sources are detected at Ks only; their spatial distribution with respect to the extinction suggests they are highly reddened cluster members. Detectable Ks-band excess is found toward 29 +/- 3 % of the stars. For comparison to a similar area of Orion observed in the near-infrared, mass and extinction cuts are ...

  18. HST WFC3 Observations of Uranus' 2014 Storm Clouds and Comparison with VLT/SINFONI and IRTF/Spex Observations

    Science.gov (United States)

    Irwin, Patrick G. J.; Wong, Michael H.; Simon, Amy A.; Orton, G. S.; Toledo, Daniel

    2017-01-01

    In November 2014 Uranus was observed with the Wide Field Camera 3 (WFC3) instrument of the Hubble Space Telescope as part of the Hubble 2020: Outer Planet Atmospheres Legacy program, OPAL. OPAL annually maps Jupiter, Uranus and Neptune (and will also map Saturn from 2018) in several visible near- infrared wavelength filters. The Uranus 2014 OPAL observations were made on the 89th November at a time when a huge cloud complex, first observed by de Pater et al. (2015) and subsequently tracked by professional and amateur astronomers (Sayanagi et al., 2016), was present at 30-40deg N. We imaged the entire visible atmosphere, including the storm system, in seven filters spanning 467924 nm, capturing variations in the coloration of Uranus clouds and also vertical distribution due to wavelength dependent changes in Rayleigh scattering and methane absorption optical depth. Here we analyse these new HST observations with the NEMESIS radiative-transfer and retrieval code in multiple-scattering mode to determine the vertical cloud structure in and around the storm cloud system. The same storm system was also observed in the H-band (1.4-1.8 micrometers) with the SINFONI Integral Field Unit Spectrometer on the Very Large Telescope (VLT) on 31st October and 11th November, reported by Irwin et al. (2016, 10.1016j.icarus.2015.09.010). To constrain better the cloud particle sizes and scattering properties over a wide wavelength range we also conducted a limb-darkening analysis of the background cloud structure in the 30-40deg N latitude band by simultaneously fitting: a) these HSTOPAL observations at a range of zenith angles; b) the VLTSINFONI observations at a range of zenith angles; and c) IRTFSpeX observations of this latitude band made in 2009 at a single zenith angle of 23deg, spanning the wavelength range 0.8-1.8 micrometers (Irwin et al., 2015, 10.1016j.icarus.2014.12.020). We find that the HST observations, and the combined HSTVLTIRTF observations at all locations are well

  19. The VLT-FLAMES Tarantula Survey. XXV. Surface nitrogen abundances of O-type giants and supergiants

    Science.gov (United States)

    Grin, N. J.; Ramírez-Agudelo, O. H.; de Koter, A.; Sana, H.; Puls, J.; Brott, I.; Crowther, P. A.; Dufton, P. L.; Evans, C. J.; Gräfener, G.; Herrero, A.; Langer, N.; Lennon, D. J.; van Loon, J. Th.; Markova, N.; de Mink, S. E.; Najarro, F.; Schneider, F. R. N.; Taylor, W. D.; Tramper, F.; Vink, J. S.; Walborn, N. R.

    2017-04-01

    Context. Theoretically, rotation-induced chemical mixing in massive stars has far reaching evolutionary consequences, affecting the sequence of morphological phases, lifetimes, nucleosynthesis, and supernova characteristics. Aims: Using a sample of 72 presumably single O-type giants to supergiants observed in the context of the VLT-FLAMES Tarantula Survey (VFTS), we aim to investigate rotational mixing in evolved core-hydrogen burning stars initially more massive than 15 M⊙ by analysing their surface nitrogen abundances. Methods: Using stellar and wind properties derived in a previous VFTS study we computed synthetic spectra for a set of up to 21 N ii-v lines in the optical spectral range, using the non-LTE atmosphere code FASTWIND. We constrained the nitrogen abundance by fitting the equivalent widths of relatively strong lines that are sensitive to changes in the abundance of this element. Given the quality of the data, we constrained the nitrogen abundance in 38 cases; for 34 stars only upper limits could be derived, which includes almost all stars rotating at νesini> 200 km s-1. Results: We analysed the nitrogen abundance as a function of projected rotation rate νesini and confronted it with predictions of rotational mixing. We found a group of N-enhanced slowly-spinning stars that is not in accordance with predictions of rotational mixing in single stars. Among O-type stars with (rotation-corrected) gravities less than log gc = 3.75 this group constitutes 30-40 percent of the population. We found a correlation between nitrogen and helium abundance which is consistent with expectations, suggesting that, whatever the mechanism that brings N to the surface, it displays CNO-processed material. For the rapidly-spinning O-type stars we can only provide upper limits on the nitrogen abundance, which are not in violation with theoretical expectations. Hence, the data cannot be used to test the physics of rotation induced mixing in the regime of high spin rates

  20. Raman Spectra of Glasses

    Science.gov (United States)

    1986-11-30

    17), Raman spectra, plus a , . theoretical treatment of the data, f complex fluorozirconate 14 I anions in ZBLAN glasses and melts (16), and...based ZBLAN glasses ) 17. ICORS (International Conference on Raman Spectroscopy) Proceedings, London, England. Conferencf 5-9 Sep 88. (Molten silica...RESEARCH FINAL REPORT DTIC CONTRACT N00014-81-K-0501 &JELECTE 1 MAY 81 -- 30 NOV 86 EJJAN041989 V "RAMAN SPECTRA OF GLASSES " 0 During the five years of the

  1. FORS2/VLT survey of Milky Way globular clusters I. Description of the method for derivation of metal abundances in the optical and application to NGC 6528, NGC 6553, M 71, NGC 6558, NGC 6426 and Terzan 8

    CERN Document Server

    Dias, Bruno; Saviane, Ivo; Held, Enrico; Da Costa, Gary; Ortolani, Sergio; Vasquez, Sergio; Gullieuszik, Marco; Katz, David

    2014-01-01

    (abridged) We have observed almost 1/3 of the globular clusters in the Milky Way, targeting distant and/or highly reddened objects, besides a few reference clusters. A large sample of red giant stars was observed with FORS2@VLT/ESO at R ~ 2,000. The method for derivation of stellar parameters is presented with application to six reference clusters. We aim at deriving the stellar parameters effective temperature, gravity, metallicity and alpha-element enhancement, as well as radial velocity, for membership confirmation of individual stars in each cluster. We analyse the spectra collected for the reference globular clusters NGC 6528, NGC 6553, M 71, NGC 6558, NGC 6426 and Terzan 8. They cover the full range of globular cluster metallicities, and are located in the bulge, disc and halo. Full spectrum fitting techniques are applied, by comparing each target spectrum with a stellar library in the optical region at 4560-5860 A. We employed the library of observed spectra MILES, and the synthetic library by Coelho e...

  2. VLT 8.2-m Unit Telescope no. 1 (as on September 7, 1995)

    Science.gov (United States)

    1995-09-01

    ESO Press Photos 28-30/95; 13 September 1995 The construction of the ESO Very Large Telescope (VLT) advances rapidly, both in Europe and in Chile. These three photos show some of the main mechanical parts of the first 8.2-metre telescope, as they presented themselves in Milan (Italy) on Thursday, September 7, 1995. Two versions of these photos, one smaller and one larger and with better image resolution, are accessible for convenient transfer over the networks. The mechanical structure of VLT Unit Telescope no. 1 is now in the process of being mounted at the Ansaldo Energia premises in Milan (Italy). The so-called main structure (i.e., telescope azimuth and altitude mechanical structure, including hydrostatic bearing system, direct drives and direct mounted encoding system) was designed and is being built by the Italian consortium AES, composed of Ansaldo Energia (Genova), SOIMI (Milan) and EIE (Venice). Already two months from now, in November 1995, the complete, enormous mechanical structures of this telescope will be moving on the azimuth hydrostatic bearing tracks, using the direct drive system designed and built by the PHASE Company (Genova, Italy). The thorough testing phase will start by the end of December 1995 or at the beginning of January 1996. ESO Press Photo 28/95 [54K] [248K] shows the lower part of the azimuth structure of the telescope (the fork) on the concrete pier on which the azimuth tracks (hydrostatic bearing journal) are mounted. The very high accuracy of this enormous structure (compare with the persons in the photo!) is illustrated by the fact that the "run-out" of the azimuth axis of the fork has been measured as only 80 microns (0.08 millimetres) on 90 degrees turning angle. This is a remarkable result, especially since the centering of the axis is done on a radial journal with a diameter of no less than 9 metres. When the fork is equipped with all auxiliary systems, it will weigh about 320 t, will be 18 metres long and 8 metres wide. It

  3. Mapping of Ozone on Mars at Infrared Wavelengths Using Crires at VLT

    Science.gov (United States)

    Radeva, Y. L.; Mumma, M. J.; Villanueva, G.; Novak, R.; Hartogh, P.; Encrenaz, T.; Kaufl, H.; Smette, A.

    2010-12-01

    We present spatially resolved maps of ozone and water on Mars, acquired on 21 August 2009 using the ultra-high resolution infrared spectrometer CRIRES at ESO’s VLT (Paranal, Chile). On Mars, the season was mid-summer in the South (Ls = 325) and the latitudinal resolution was 10 degrees FWHM at disk center. Ozone is produced by recombination of photochemically produced O and O2. It is destroyed by UV photolysis (with O2 (a1Dg) as a principal product) but also by reaction with odd hydrogen species (especially, H - a product of H2O vapor photolysis). Thus, simultaneous measurements of water and ozone can test this relationship. We quantified ozone using spectral lines (near 1.27 mm) of O2 (a1Dg). The emission from O2 (a1Dg) serves as a tracer for O3 above 20 km, since at lower altitudes collisions with CO2 quench the excited O2 (a1Dg) molecules. We confirmed the vertical location of the O2 (a1Dg) emission by extracting rotational temperatures from line-by-line ratios, and comparing them with standard vertical temperature profiles for this season and location(s). On the same night, we also obtained 2-D (lat-long) maps of Martian water from multiple H2O lines detected in the 3.3 mm region. We compare our retrieved distributions for ozone (latitude and altitude) with predictions of Lefevre et al. [I] based on their comprehensive 3-D circulation and photochemical model for the Martian atmosphere. Acknowledgements: This work was funded by NASA’s R&A Programs in Astrobiology (344-53-51), Planetary Astronomy (344-32-51-96), and Planetary Atmospheres (NNX09AB65G). We gratefully acknowledge the Director and staff of the European Southern Observatory, for supporting these observations. References: [I] Lefevre et al. (2004), J. of Geophys. Res. 109, E07004

  4. Spectral mapping of comet 67P/Churyumov-Gerasimenko with VLT/MUSE and SINFONI

    Science.gov (United States)

    Guilbert-Lepoutre, Aurelie; Besse, Sebastien; Snodgrass, Colin; Yang, Bin

    2016-10-01

    Comets are supposedly the most primitive objects in the solar system, preserving the earliest record of material from the nebula out of which our Sun and planets were formed, and thus holding crucial clues on the early phases of the solar system formation and evolution. For most small bodies in the solar system we can only access the surface properties, whereas active comet nuclei lose material from their subsurface, so that understanding cometary activity represents an unique opportunity to assess their internal composition, and by extension the composition, the temperature and pressure conditions of the protoplanetary disk at their place of formation.The ESA/Rosetta mission is performing the most thorough investigation of a comet ever made. Rosetta is measuring properties of comet 67P/Churyumov-Gerasimenko at distances between 5 and hundreds of km from the nucleus. However, it is unable to make any measurement over the thousands of km of the rest of the coma. Fortunately, the outer coma is accessible from the ground. In addition, we currently lack an understanding of how the very detailed information gathered from space-based observations can be extrapolated to the many ground-based observations that we can potentially perform. Combining parallel in situ observations with observations from the ground therefore gives us a great opportunity, not only to understand the behavior of 67P, but also to other comets observed exclusively from Earth. As part of the many observations taken from the ground, we have performed a spectral mapping of 67's coma using two IFU instruments mounted on the VLT: MUSE in the visible, and SINFONI in the near-infrared. The observations, carried out in March 2016, will be presented and discussed.

  5. Star on the Run - Speeding Star Observed with VLT hints at Massive Black Hole

    Science.gov (United States)

    2005-11-01

    Using ESO's Very Large Telescope, astronomers [1] have recorded a massive star moving at more than 2.6 million kilometres per hour. Stars are not born with such large velocities. Its position in the sky leads to the suggestion that the star was kicked out from the Large Magellanic Cloud, providing indirect evidence for a massive black hole in the Milky Way's closest neighbour. These results will soon be published in the Astrophysical Journal Letters [2]. "At such a speed, the star would go around the Earth in less than a minute!", says Uli Heber, one of the scientists at the Dr. Remeis-Sternwarte (University of Erlangen-Nürnberg, Germany) and the Centre for Astrophysics Research (University of Hertfordshire, UK) who conducted the study. The hot massive star was discovered in the framework of the Hamburg/ESO sky survey far out in the halo of the Milky Way, towards the Doradus Constellation ("the Swordfish"). "This is a rather unusual place for such a star: massive stars are ordinarily found in the disc of the Milky Way", explains Ralf Napiwotzki, another member of the team. "Our data obtained with the UVES instrument on the Very Large Telescope, at Paranal (Chile), confirm the star to be rather young and to have a chemical composition similar to our Sun." The data also revealed the high speed of the star, solving the riddle of its present location: the star did not form in the Milky Way halo, but happens to be there while on its interstellar - or intergalactic - travel. "But when we calculated how long it would take for the star to travel from the centre of our Galaxy to its present location, we found this to be more than three times its age", says Heber. "Either the star is older than it appears or it was born and accelerated elsewhere", he adds. As a matter of fact, HE0457-5439 - as the star is called - lies closer to one of the Milky Way satellite galaxies, the Large Magellanic Cloud (LMC), located 160,000 light-years away from us. The astronomers find it likely

  6. Corneal specular microscopy in infectious and noninfectious uveitis Microscopia especular de córnea em pacientes com uveítes infecciosas e não-infecciosas

    Directory of Open Access Journals (Sweden)

    Filipe de Oliveira

    2009-08-01

    Full Text Available PURPOSE: Involvement of the cornea endothelium during uveitis has not been extensively studied even though it might participate in or constitute a target of ocular inflammation. Formation of keratic precipitates (KP is a characteristic finding in several forms of uveitis. The aim of this prospective study was to examine the vicinity of keratic precipitates in infectious and noninfectious uveitis by specular microscopy. METHODS: Patients with infectious and noninfectious uveitis in any activity level and presence of keratic precipitates were enrolled. The mean age was 40.5 years (± 14.2 years. A Topcon SP-2000P noncontact specular microscope was used to capture endothelial images in the vicinity of keratic precipitates. Automated morphometric analysis was done for cell size, cell density and cells coefficient of variation. Statistical comparisons were made between the infectious and noninfectious groups. RESULTS: From the 25 patients enrolled in this study, 16 (44% eyes presented infectious uveitis, 19 (53% noninfectious uveitis and 1 (3% eye was excluded due to the impossibility to obtain a specular image. The mean cell density estimated was 2,628 ± 204 cells/mm² in infectious group and 2,622 ± 357 cells/mm² in noninfectious group. The mean cellular area in infectious and noninfectious group was respectively 385 ± 31 µm² and 390 ± 60 µm². The coefficient of variation (% of the cellular area in the vicinity of keratic precipitates was 26.36 ±3.44 in infectious and 27.69 ± 4.61 in noninfectious group. The differences between the groups were not statistically significant (POBJETIVO: Avaliar o endotélio corneano na presença de precipitados ceráticos em pacientes portadores de uveítes infecciosas e não-infecciosas com emprego da microscopia especular de não-contato. MÉTODOS: Prospectivamente foram incluídos 25 pacientes com média de idade de 40,5 (±14,2 anos. Os pacientes foram divididos em dois grupos de acordo com a etiologia

  7. Spectra and strains

    CERN Document Server

    Golyshev, V

    2008-01-01

    This is a blend of two informal reports on the activities of the seminar on Galois representations and mirror symmetry given at the Conference on classification problems and mirror duality at the Steklov Institute, in March 2006, and at the Seminar on Algebra, Geometry and Physics at MPI, in November 2007. We assess where we are on the issue of the spectra of Fano varieties, and state problems. We introduce higher dimensional irreducible analogues of dessins, the low ramified sheaves, and hypothesize that Fano spectra relate to their geometric conductors. We give a recipe to a physicist.

  8. Spectroscopic monitoring of the luminous blue variable Westerlund1-243 from 2002 to 2009

    CERN Document Server

    Ritchie, B W; Negueruela, I; Najarro, F

    2009-01-01

    The massive post-Main Sequence star W243 in the galactic starburst cluster Westerlund 1 has undergone a spectral transformation from a B2Ia supergiant devoid of emission features in 1981 to an A-type supergiant with a rich emission-line spectrum by 2002/03. We used VLT/UVES and VLT/FLAMES to obtain high-resolution spectra on six epochs in 2003/04 (UVES) and ten epochs in 2008/09 (FLAMES). These spectra are used alongside other VLT/FLAMES and NTT/EMMI spectra to follow the evolution of W243 from 2002 to 2009. W243 displays a complex, time-varying spectrum with emission lines of Hydrogen, Helium and Lyman-pumped metals, forbidden lines of Nitrogen and Iron, and a large number of absorption lines from neutral and singly-ionized metals. Many lines are complex emission/absorption blends. The LBV has a current temperature of ~8500K (spectral type A3Ia+), and displays signs of photospheric pulsations and weak episodic mass loss. Nitrogen is highly overabundant, with Carbon and Oxygen depleted, indicative of surface ...

  9. On-sky results of the adaptive optics MACAO for the new IR-spectrograph CRIRES at VLT

    CERN Document Server

    Paufique, J; Delabre, B; Donaldson, R; Esteves, R; Fedrigo, E; Gigan, P; Gojak, D; Hubin, N; Kasper, M; Kaeufl, U; Lizon, J L; Marchetti, E; Oberti, S; Pirard, J F; Pozna, E; Santos, J; Stroebele, S; Tordo, S; Lizon, JL.; Pirard, JF.

    2006-01-01

    The adaptive optics MACAO has been implemented in 6 focii of the VLT observatory, in three different flavors. We present in this paper the results obtained during the commissioning of the last of these units, MACAO-CRIRES. CRIRES is a high-resolution spectrograph, which efficiency will be improved by a factor two at least for point-sources observations with a NGS brighter than R=15. During the commissioning, Strehl exceeding 60% have been observed with fair seeing conditions, and a general description of the performance of this curvature adaptive optics system is done.

  10. The Stellar Mass Functions of the CLASH-VLT Clusters MACS J1206-0847 and Abell 209

    Science.gov (United States)

    Annunziatella, M.; Biviano, A.; Mercurio, A.; Nonino, M.; Rosati, P.; Balestra, I.; Girardi, M.; Grillo, C.

    The study of the galaxy stellar mass function, and in particular its dependence from the environment, represents a key observable to discriminate between different models of galaxy evolution. We determined the stellar mass function (SMF) of passive and star-forming (SF) galaxies in different regions of two clusters in the CLASH-VLT sample, MACS J1206.2-0847 and Abell 209. Since these two clusters are at different redshifts, the comparison between the results obtained in the two cases can inform us about the evolution of the SMF with cosmic time.

  11. VLT optical observations of V821 Ara(=GX339-4) in an extended "off" state

    CERN Document Server

    Shahbaz, T; Charles, P A

    2001-01-01

    We report on low-resolution spectroscopy of GX339-4 during its current, extended X-ray `off' state in May 2000 (r=20.1) obtained with the VLT Focal Reducer/low dispersion Spectrograph (FORS1). Although we do not positively detect the secondary star in GX339-4 we place an upper limit of 30 percent on the contribution of a ``normal'' K-type secondary star spectrum to the observed flux. Using this limit for the observed magnitude of the secondary star, we find a lower limit for the distance of GX339-4 to be 5.6 kpc.

  12. Atomic Spectra Database (ASD)

    Science.gov (United States)

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  13. Using fear appeals in warning labels to promote responsible gambling among VLT players: the key role of depth of information processing.

    Science.gov (United States)

    Munoz, Yaromir; Chebat, Jean-Charles; Suissa, Jacob Amnon

    2010-12-01

    Video lottery terminals (VLT) are a highly lucrative gambling format, but at the same time they are among the most hazardous. Previous research has shown that threatening warnings may be an appropriate approach for promoting protective behavior. The present study explores the potential benefits of threatening warnings in the fight against compulsive gambling. A 4 × 2 factorial design experiment was used to test our model based on both Elaboration Likelihood Model and Protection Motivation Theory. 258 VLT adult players (58% males, 42% females) with various degrees of problem gambling were exposed to three threat levels (plus a control condition) from two different sources (i.e., either a medical source or a source related to the provider of VLT's). Our results show that both higher threat warnings and the medical source of warnings enhance Depth of Information Processing. It was also found that Depth of Information Processing affects positively attitude change and compliance intentions. The theoretical and managerial implications are discussed.

  14. CLASH-VLT: testing the nature of gravity with galaxy cluster mass profiles

    Science.gov (United States)

    Pizzuti, L.; Sartoris, B.; Borgani, S.; Amendola, L.; Umetsu, K.; Biviano, A.; Girardi, M.; Rosati, P.; Balestra, I.; Caminha, G. B.; Frye, B.; Koekemoer, A.; Grillo, C.; Lombardi, M.; Mercurio, A.; Nonino, M.

    2016-04-01

    We use high-precision kinematic and lensing measurements of the total mass profile of the dynamically relaxed galaxy cluster MACS J1206.2-0847 at z=0.44 to estimate the value of the ratio η=Ψ/Φ between the two scalar potentials in the linear perturbed Friedmann-Lemaitre-Robertson-Walker metric. An accurate measurement of this ratio, called anisotropic stress, could show possible, interesting deviations from the predictions of the theory of General Relativity, according to which Ψ should be equal to Φ. Complementary kinematic and lensing mass profiles were derived from exhaustive analyses using the data from the Cluster Lensing And Supernova survey with Hubble (CLASH) and the spectroscopic follow-up with the Very Large Telescope (CLASH-VLT). Whereas the kinematic mass profile tracks only the time-time part of the perturbed metric (i.e. only Φ), the lensing mass profile reflects the contribution of both time-time and space-space components (i.e. the sum Φ+Ψ). We thus express η as a function of the mass profiles and perform our analysis over the radial range 0.5 MpcFrenk-White mass profile, which well fits the data, we obtain η(r200)=1.01 -0.28+0.31 at the 68% C.L. We discuss the effect of assuming different functional forms for mass profiles and of the orbit anisotropy in the kinematic reconstruction. Interpreting this result within the well-studied f(R) modified gravity model, the constraint on η translates into an upper bound to the interaction length (inverse of the scalaron mass) smaller than 2 Mpc. This tight constraint on the f(R) interaction range is however substantially relaxed when systematic uncertainties in the analysis are considered. Our analysis highlights the potential of this method to detect deviations from general relativity, while calling for the need of further high-quality data on the total mass distribution of clusters and improved control on systematic effects.

  15. VLT/ISAAC Spectra of the H-beta Region in Intermediate-Redshift Quasars II. Black Hole Mass and Eddington Ratio

    CERN Document Server

    Sulentic, J W; Stirpe, G M; Marziani, P; Dultzin-Hacyan, D; Calvani, M

    2006-01-01

    We derive black hole masses for a sample of about 300 AGNs in the redshift range 0 9.5 and suggest that extremely large M values (log M >~ 10) may not be realistic. Derived Eddington ratio values values show no evidence for a significant population of super-Eddington radiators especially after correction is made for sources with extreme orientation to our line of sight. Sources with FWHM(Hbeta broad component) <~ 4000 km/s show systematically higher Eddington ratio and lower M values than broader lined AGNs (including almost all radio-loud sources).

  16. CLASH-VLT: Substructure in the galaxy cluster MACS J1206.2-0847 from kinematics of galaxy populations

    CERN Document Server

    Girardi, M; Balestra, I; Nonino, M; Biviano, A; Grillo, C; Rosati, P; Annunziatella, M; Demarco, R; Fritz, A; Gobat, R; Lemze, D; Presotto, V; Scodeggio, M; Tozzi, P; Caminha, G Bartosch; Brescia, M; Coe, D; Kelson, D; Koekemoer, A; Lombardi, M; Medezinski, E; Postman, M; Sartoris, B; Umetsu, K; Zitrin, A; Boschin, W; Czoske, O; De Lucia, G; Kuchner, U; Maier, C; Meneghetti, M; Monaco, P; Monna, A; Munari, E; Seitz, S; Verdugo, M; Ziegler, B

    2015-01-01

    In the effort to understand the link between the structure of galaxy clusters and their galaxy populations, we focus on MACS J1206.2-0847, at z~0.44, probing its substructure in the projected phase space through the spectrophotometric properties of a large number of galaxies from the CLASH-VLT survey. Our analysis is mainly based on an extensive spectroscopic dataset of 445 member galaxies, mostly acquired with VIMOS@VLT as part of our ESO Large Programme, sampling the cluster out to a radius ~2R200 (4 Mpc). We classify 412 galaxies as: passive, with strong Hdelta absorption (red and blue ones), and with emission lines from weak to very strong ones. A number of tests for substructure detection is applied to analyze the galaxy distribution in the velocity space, in the 2D space, and in the (3D) projected phase-space. Studied in its entirety, the cluster appears as a large-scale relaxed system with a few, secondary, minor overdensities in 2D distribution. We detect no velocity gradient or evidence of deviations...

  17. Is Fear to Intervene with Problem Gamblers Related to Interveners' Gender and Status? A Study with VLT Operators.

    Science.gov (United States)

    Tomei, Alexander; Zumwald, Coralie

    2017-03-01

    We assess how video lottery terminal (VLT) operators' self-perceive their ability to recognize a problem gambler, to what extent they are approached by problem gamblers seeking for assistance, how many detections and interventions they report, and the reasons they give for not intervening with clients who show signs of problem gambling. We also examine how these variables are related to the operators' gender and status in the establishment. 177 VLT operators anonymously completed a structured questionnaire at the beginning of a responsible gambling training class held in different French-speaking Swiss towns. The operators felt confident in their ability to detect problem gambling behaviors, were rarely approached by problem gamblers seeking assistance, and reported fewer interventions compared to the number of detections. This reluctance to intervene was mainly attributed to the fear of potential negative reactions from the client. Female staff were the most reluctant to intervene and the most fearful of potential negative reactions from the client. Responsible gambling training programs should include coping strategies for dealing with potential negative reactions from clients. Our findings suggest that staff gender and status are two individual characteristics that should be taken into account when planning responsible gambling trainings.

  18. The VLT observations of the HDF-S NICMOS field photometric catalog and high redshift galaxy candidates

    CERN Document Server

    Fontana, A; Fosbury, R A E; Giallongo, E; Hook, R N; Poli, F; Renzini, A; Rosati, P; Viezzer, R

    1999-01-01

    We present the deep UBVRI observations of the HDF-S NICMOS field obtained as part of the Science Verification of the VLT Unit 1 telescope. The images have been used to construct object catalogs and to obtain photometric redshifts. The effective field of view is $\\simeq 70\\times70$ arcsec$^2$, and the formal $5\\sigma$ limiting magnitudes (in a 2 FWHM aperture) are 26.3, 27.8, 27.5, 26.9, 25.2 in the $U$, $B$, $V$, $R$ and $I$ bands, respectively. Thanks to the sub-arcsecond image quality, relatively long exposure time, and large collecting area of the VLT, this is the deepest set of multicolor images ever obtained from a ground-based telescope. Galaxy counts have been derived independently in each band, and show no significant departures from previous data from wider areas. A multicolor photometric catalog of all the galaxies selected in the $R$ band has also been obtained and used to derive photometric redshifts for all galaxies with $R \\leq 26.5 $, using also the J,H and K magnitudes from the NICMOS deep obs...

  19. CLASH-VLT: Strangulation of cluster galaxies in MACSJ0416.1-2403 as seen by their chemical enrichment

    CERN Document Server

    Maier, C; Ziegler, B L; Verdugo, M; Balestra, I; Girardi, M; Mercurio, A; Rosati, P; Fritz, A; Grillo, C; Nonino, M; Sartoris, B

    2016-01-01

    (abridged) We explore the Frontier Fields cluster MACS J0416.1-2403 at z=0.3972 with VIMOS/VLT spectroscopy from the CLASH-VLT survey covering a region which corresponds to almost three virial radii. We measure fluxes of 5 emission lines of 76 cluster members enabling us to unambiguously derive O/H gas metallicities, and also SFRs from Halpha. For intermediate massses we find a similar distribution of cluster and field galaxies in the MZR and mass vs. sSFR diagrams. Bulge-dominated cluster galaxies have on average lower sSFRs and higher O/Hs compared to their disk-dominated counterparts. We use the location of galaxies in the projected velocity vs. position phase-space to separate our cluster sample into a region of objects accreted longer time ago and a region of recently accreted and infalling galaxies. We find a higher fraction of accreted metal-rich galaxies (63%) compared to the fraction of 28% of metal-rich galaxies in the infalling regions. Intermediate mass galaxies falling into the cluster for the fi...

  20. VLT identification of the optical afterglow of the gamma-ray burst GRB000131 at z=4.50

    DEFF Research Database (Denmark)

    Andersen, M.I.; Hjorth, J.; Jesen, B.L.

    2000-01-01

    Angstrom. This places GRB 000131 at a redshift of 4.500 +/- 0.015. The inferred isotropic energy release in gamma rays alone was similar to 10(54) erg (depending on the assumed cosmology). The rapid power-law decay of the afterglow (index alpha = 2.25, similar to bursts with a prior break in the lightcurve......We report the discovery of the gamma-ray burst GRB 000131 and its optical afterglow. The optical identification was made with the VLT 84 hours after the burst following a BATSE detection and an Inter Planetary Network localization. GRB 000131 was a bright, long-duration GRB, with an apparent...... precursor signal 62 s prior to trigger. The afterglow was detected in ESO VLT, NTT, and DK1.54m follow-up observations. Broad-band and spectroscopic observations of the spectral energy distribution reveals a sharp break at optical wavelengths which is interpreted as a Ly alpha absorption edge at 6700...

  1. VLT identification of the optical afterglow of the gamma-ray burst GRB 000131 at z=4.50

    DEFF Research Database (Denmark)

    Andersen, M.I.; Hjorth, J.; Pedersen, H.

    2000-01-01

    Angstrom. This places GRB 000131 at a redshift of 4.500 +/- 0.015. The inferred isotropic energy release in gamma rays alone was similar to 10(54) erg (depending on the assumed cosmology). The rapid power-law decay of the afterglow (index alpha = 2.25, similar to bursts with a prior break in the lightcurve......We report the discovery of the gamma-ray burst GRB 000131 and its optical afterglow. The optical identification was made with the VLT 84 hours after the burst following a BATSE detection and an Inter Planetary Network localization. GRB 000131 was a bright, long-duration GRB, with an apparent...... precursor signal 62 s prior to trigger. The afterglow was detected in ESO VLT, NTT, and DK1.54m follow-up observations. Broad-band and spectroscopic observations of the spectral energy distribution reveals a sharp break at optical wavelengths which is interpreted as a Ly alpha absorption edge at 6700...

  2. ESPRESSO instrument control electronics: a PLC based distributed layout for a second generation instrument at ESO VLT

    Science.gov (United States)

    Baldini, V.; Cirami, R.; Coretti, I.; Cristiani, S.; Di Marcantonio, P.; Mannetta, M.; Santin, P.; Mégevand, D.; Zerbi, F.

    2014-07-01

    ESPRESSO is an ultra-stable fiber-fed spectrograph designed to combine incoherently the light coming from up to 4 Unit Telescopes of the ESO VLT. From the Nasmyth focus of each telescope the light, through an optical path, is fed by the Coudé Train subsystems to the Front End Unit placed in the Combined Coudé Laboratory. The Front End is composed by one arm for each telescope and its task is to convey the incoming light, after a calibration process, into the spectrograph fibers. To perform these operations a large number of functions are foreseen, like motorized stages, lamps, digital and analog sensors that, coupled with dedicated Technical CCDs (two per arms), allow to stabilize the incoming beam up to the level needed to exploit the ESPRESSO scientific requirements. The Instrument Control Electronics goal is to properly control all the functions in the Combined Coudé Laboratory and the spectrograph itself. It is fully based on a distributed PLC architecture, abandoning in this way the VME-based technology previously adopted for the ESO VLT instruments. In this paper we will describe the ESPRESSO Instrument Control Electronics architecture, focusing on the distributed layout and its interfaces with the other ESPRESSO subsystems.

  3. VLT identification of the optical afterglow of the gamma-ray burst GRB 000131 at z=4.50

    DEFF Research Database (Denmark)

    Andersen, M.I.; Hjorth, J.; Pedersen, H.

    2000-01-01

    Angstrom. This places GRB 000131 at a redshift of 4.500 +/- 0.015. The inferred isotropic energy release in gamma rays alone was similar to 10(54) erg (depending on the assumed cosmology). The rapid power-law decay of the afterglow (index alpha = 2.25, similar to bursts with a prior break in the lightcurve......We report the discovery of the gamma-ray burst GRB 000131 and its optical afterglow. The optical identification was made with the VLT 84 hours after the burst following a BATSE detection and an Inter Planetary Network localization. GRB 000131 was a bright, long-duration GRB, with an apparent...... precursor signal 62 s prior to trigger. The afterglow was detected in ESO VLT, NTT, and DK1.54m follow-up observations. Broad-band and spectroscopic observations of the spectral energy distribution reveals a sharp break at optical wavelengths which is interpreted as a Ly alpha absorption edge at 6700...

  4. VLT identification of the optical afterglow of the gamma-ray burst GRB000131 at z=4.50

    DEFF Research Database (Denmark)

    Andersen, M.I.; Hjorth, J.; Jesen, B.L.

    2000-01-01

    Angstrom. This places GRB 000131 at a redshift of 4.500 +/- 0.015. The inferred isotropic energy release in gamma rays alone was similar to 10(54) erg (depending on the assumed cosmology). The rapid power-law decay of the afterglow (index alpha = 2.25, similar to bursts with a prior break in the lightcurve......We report the discovery of the gamma-ray burst GRB 000131 and its optical afterglow. The optical identification was made with the VLT 84 hours after the burst following a BATSE detection and an Inter Planetary Network localization. GRB 000131 was a bright, long-duration GRB, with an apparent...... precursor signal 62 s prior to trigger. The afterglow was detected in ESO VLT, NTT, and DK1.54m follow-up observations. Broad-band and spectroscopic observations of the spectral energy distribution reveals a sharp break at optical wavelengths which is interpreted as a Ly alpha absorption edge at 6700...

  5. VLT identification of the optical afterglow of the gamma-ray burst GRB 000131 at z=4.50

    DEFF Research Database (Denmark)

    Andersen, M. I.; Hjorth, J.; Pedersen, H.

    2000-01-01

    . This places GRB 000131 at a redshift of 4.500 +/- 0.015. The inferred isotropic energy release in gamma rays alone was approximately 10^54 erg (depending on the assumed cosmology). The rapid power-law decay of the afterglow (index alpha=2.25, similar to bursts with a prior break in the lightcurve), however......We report the discovery of the gamma-ray burst GRB 000131 and its optical afterglow. The optical identification was made with the VLT 84 hours after the burst following a BATSE detection and an Inter Planetary Network localization. GRB 000131 was a bright, long-duration GRB, with an apparent...... precursor signal 62 s prior to trigger. The afterglow was detected in ESO VLT, NTT, and DK1.54m follow-up observations. Broad-band and spectroscopic observations of the spectral energy distribution reveals a sharp break at optical wavelengths which is interpreted as a Ly-alpha absorption edge at 6700 A...

  6. The VLT LBG Redshift Survey - III. The clustering and dynamics of Lyman-break galaxies at z ~ 3

    CERN Document Server

    Bielby, R; Shanks, T; Crighton, N H M; Infante, L; Bornancini, C G; Francke, H; Heraudeau, P; Lambas, D G; Metcalfe, N; Minniti, D; Padilla, N; Theuns, T; Tummuangpak, P; Weilbacher, P

    2012-01-01

    We present a survey of 2,148 galaxy redshifts from the VLT LBG Redshift Survey (VLRS), a spectroscopic survey of z ~ 3 galaxies in wide fields centred on background QSOs made using the VLT VIMOS instrument. To make a definitive LBG clustering analysis, we have combined the VLRS redshifts with the 813 Keck LBG redshifts of Steidel et al, with the statistical power of VLRS at large scales complementing the accuracy of the Keck sample at small scales. From the semi-projected correlation function for the VLRS and combined surveys, we find that the results are well fit with a single power law model for the real space correlation function with clustering scale lengths of respectively r0 = 3.32 \\pm 0.41 and 3.75 \\pm 0.24 Mpc/h. We note that the corresponding combined slope is flatter than for local galaxies at {\\gamma} = 1.55 \\pm 0.09. This flat slope is confirmed by the z-space correlation function and in the range 10 < s < 100 Mpc/h the VLRS shows a 2.5{\\sigma} excess over the {\\Lambda}CDM linear prediction....

  7. Direct recovery of fluctuation spectra from tomographic shear spectra

    Science.gov (United States)

    Mezzetti, Marino; Bonometto, Silvio A.; Casarini, Luciano; Murante, Giuseppe

    2012-06-01

    Forthcoming experiments will enable us to determine high precision tomographic shear spectra. Matter density fluctuation spectra, at various z, should then be recovered from them, in order to constrain the model and determine the DE state equation. Available analytical expressions, however, do the opposite, enabling us to derive shear spectra from fluctuation spectra. Here we find the inverse expression, yielding density fluctuation spectra from observational tomographic shear spectra. The procedure involves SVD techniques for matrix inversion. We show in detail how the approach works and provide a few examples.

  8. VLT/X-shooter spectroscopy of the GRB 090926A afterglow

    NARCIS (Netherlands)

    D'Elia, V.; Fynbo, J.P.U.; Covino, S.; Goldoni, P.; Jakobsson, P.; Matteucci, F.; Piranomonte, S.; Sollerman, J.; Thöne, C.C.; Vergani, S.D.; Vreeswijk, P.M.; Watson, D.J.; Wiersema, K.; Zafar, T.; de Ugarte Postigo, A.; Flores, H.; Hjorth, J.; Kaper, L.; Levan, A.J.; Malesani, D.; Milvang-Jensen, B.; Pian, E.; Tagliaferri, G.; Tanvir, N.R.

    2010-01-01

    Aims. The aim of this paper is to study the environment and intervening absorbers of the gamma-ray burst GRB090926A through analyzing optical spectra of its afterglow. Methods. We analyzed medium-resolution spectroscopic observations (R = 10 000, corresponding to 30 km s(-1), S/N = 15-30 and wavelen

  9. Uveíte anterior como manifestação da Doença de Kikuchi e Fujimoto Anterior Uveitis as an ocular manifestation of Kikuchi and Fujimoto's Disease

    Directory of Open Access Journals (Sweden)

    Marco Aurelio Varella Figueiredo

    2008-04-01

    Full Text Available Apresentação de um caso de febre de origem obscura numa paciente feminina de 35 anos, com queda do estado geral, adenomegalia cervical posterior, monilíase oral, parotidite e irite.Após o parecer oftalmológico, o tratamento foi iniciado e posteriormente com o resultado do exame histopatológico de um linfonodo, diagnosticou-se a Doença de Kikuchi e Fujimoto. Sugerimos que a uveíte anterior seja reconhecida como mais um sinal de suspeita desta doença. São comentados os achados oculares, os aspectos histopatológicos e o tratamento da Doença de Kikuchi e Fujimoto.Report of a case on Kikuchi and Fujimoto's Disease in a young lady who developed a long standing spiking fever, weight loss, cervical adenomegalia, oral moniliasis, parotiditis and iritis.The histopathological findings, course and treatment as well as the importance of a multidisciplinar approach are commented.

  10. Fundamental stellar parameters and metallicities from Bayesian spectroscopy: application to low- and high-resolution spectra

    Science.gov (United States)

    Schönrich, Ralph; Bergemann, Maria

    2014-09-01

    We present a unified framework to derive fundamental stellar parameters by combining all available observational and theoretical information for a star. The algorithm relies on the method of Bayesian inference, which for the first time directly integrates the spectroscopic analysis pipeline based on the global spectrum synthesis and allows for comprehensive and objective error calculations given the priors. Arbitrary input data sets can be included into our analysis and other stellar quantities, in addition to stellar age, effective temperature, surface gravity, and metallicity, can be computed on demand. We lay out the mathematical framework of the method and apply it to several observational data sets, including high- and low-resolution spectra (UVES, NARVAL, HARPS, SDSS/SEGUE). We find that simpler approximations for the spectroscopic probability distribution function, which are inherent to past Bayesian approaches, lead to deviations of several standard deviations and unreliable errors on the same data. By its flexibility and the simultaneous analysis of multiple independent measurements for a star, it will be ideal to analyse and cross-calibrate the large ongoing and forthcoming surveys, like Gaia-European Southern Observatory (ESO), SDSS, Gaia and LSST.

  11. Hydrogen and helium in the spectra of Type Ia supernovae

    CERN Document Server

    Lundqvist, Peter; Sollerman, Jesper; Kozma, Cecilia; Baron, E; Cox, Nick L J; Fransson, Claes; Leibundgut, Bruno; Spyromilio, Jason

    2013-01-01

    We present predictions for hydrogen and helium emission line luminosities from circumstellar matter around Type Ia supernovae (SNe Ia) using time dependent photoionization modeling. ESO/VLT optical echelle spectra of the SN Ia 2000cx were taken before and up to 70 days after maximum. We detect no hydrogen and helium lines, and place an upper limit on the mass loss rate for the putative wind of less than 1.3EE{-5} solar masses per year, assuming a speed of 10 km/s and solar abundances for the wind. In a helium-enriched case, the best line to constrain the mass loss would be He I 10,830 A. We confirm the details of interstellar Na I and Ca II absorption towards SN 2000cx as discussed by Patat et al., but also find evidence for 6613.56 A Diffuse Interstellar Band (DIB) absorption in the Milky Way. We discuss measurements of the X-ray emission from the interaction between the supernova ejecta and the wind and we re-evaluate observations of SN 1992A obtained 16 days after maximum by Schlegel & Petre. We find a...

  12. Spectroscopy across the brown dwarf/planetary mass boundary - I. Near-infrared JHK spectra

    CERN Document Server

    Patience, J; De Rosa, R J; Vigan, A; Witte, S; Rice, E; Helling, Ch; Hauschildt, P

    2012-01-01

    With a uniform VLT SINFONI data set of nine targets, we have developed an empirical grid of J,H,K spectra of the atmospheres of objects estimated to have very low substellar masses of \\sim5-20 MJup and young ages of \\sim1-50 Myr. Most of the targets are companions, objects which are especially valuable for comparison with atmosphere and evolutionary models, as they present rare cases in which the age is accurately known from the primary. Based on the sample youth, all objects are expected to have low surface gravity, and this study investigates the critical early phases of the evolution of substellar objects. The spectra are compared with grids of five different theoretical atmosphere models. This analysis represents the first systematic model comparison with infrared spectra of young brown dwarfs. The fits to the full JHK spectra of each object result in a range of best fit effective temperatures of +/-150-300K whether or not the full model grid or a subset restricted to lower log(g) values is used. This eff...

  13. The enigmatic He-sdB pulsator LS IV$-$14$^\\circ$116: new insights from the VLT

    CERN Document Server

    Randall, S K; Ziegerer, E; Geier, S; Fontaine, G

    2015-01-01

    The intermediate Helium subdwarf B star LS IV$-$14$^\\circ$116 is a unique object showing extremely peculiar atmospheric abundances as well as long-period pulsations that cannot be explained in terms of the usual opacity mechanism. One hypothesis invoked was that a strong magnetic field may be responsible. We discredit this possibility on the basis of FORS2 spectro-polarimetry, which allows us to rule out a mean longitudinal magnetic field down to 300 G. Using the same data, we derive the atmospheric parameters for LS IV$-$14$^\\circ$116 to be $T_{\\rm eff}$ = 31,150$\\pm$111 K, $\\log{g}$ = 5.88$\\pm$0.02 and $\\log{N(\\rm He)/N(\\rm H)}$ = $-$0.62$\\pm$0.01. The high surface gravity in particular is at odds with the theory that LS IV$-$14$^\\circ$116 has not yet settled onto the Helium Main Sequence, and that the pulsations are excited by an $\\epsilon$ mechanism acting on the Helium-burning shells present after the main Helium flash. Archival UVES spectroscopy reveals LS IV$-$14$^\\circ$116 to have a radial velocity of...

  14. Search with UVES and XSHOOTER for signatures of the low-mass secondary in the post common-envelope binary AA Dor

    CERN Document Server

    Hoyer, D; Werner, K; Hauschildt, P H; Kruk, J W

    2015-01-01

    AA Dor is a close, totally eclipsing, post common-envelope binary with an sdOB-type primary and an extremely low-mass secondary, located close to the mass limit of stable central hydrogen burning. Within error limits, it may either be a brown dwarf or a late M-type dwarf. We aim to extract the secondary's contribution to the phase-dependent composite spectra. The spectrum and identified lines of the secondary decide on its nature. In January 2014, we measured the phase-dependent spectrum of AA Dor with XSHOOTER over one complete orbital period. Since the secondary's rotation is presumable synchronized with the orbital period, its surface strictly divides into a day and night side. Therefore, we may obtain the spectrum of its cool side during its transit and of its hot, irradiated side close to its occultation. We developed the Virtual Observatory (VO) tool TLISA to search for weak lines of a faint companion in a binary system. We identified 53 spectral lines of the secondary in the ultraviolet-blue, visual, a...

  15. The VLT-FLAMES Tarantula Survey. VIII. Multiplicity properties of the O-type star population

    Science.gov (United States)

    Sana, H.; de Koter, A.; de Mink, S. E.; Dunstall, P. R.; Evans, C. J.; Hénault-Brunet, V.; Maíz Apellániz, J.; Ramírez-Agudelo, O. H.; Taylor, W. D.; Walborn, N. R.; Clark, J. S.; Crowther, P. A.; Herrero, A.; Gieles, M.; Langer, N.; Lennon, D. J.; Vink, J. S.

    2013-02-01

    Context. The Tarantula Nebula in the Large Magellanic Cloud is our closest view of a starburst region and is the ideal environment to investigate important questions regarding the formation, evolution and final fate of the most massive stars. Aims: We analyze the multiplicity properties of the massive O-type star population observed through multi-epoch spectroscopy in the framework of the VLT-FLAMES Tarantula Survey. With 360 O-type stars, this is the largest homogeneous sample of massive stars analyzed to date. Methods: We use multi-epoch spectroscopy and variability analysis to identify spectroscopic binaries. We also use a Monte-Carlo method to correct for observational biases. By modeling simultaneously the observed binary fraction, the distributions of the amplitudes of the radial velocity variations and the distribution of the time scales of these variations, we constrain the intrinsic current binary fraction and period and mass-ratio distributions. Results: We observe a spectroscopic binary fraction of 0.35 ± 0.03, which corresponds to the fraction of objects displaying statistically significant radial velocity variations with an amplitude of at least 20 km s-1. We compute the intrinsic binary fraction to be 0.51 ± 0.04. We adopt power-laws to describe the intrinsic period and mass-ratio distributions: f(log 10P/d) ~ (log 10P/d)π (with log 10P/d in the range 0.15-3.5) and f(q) ~ qκ with 0.1 ≤ q = M2/M1 ≤ 1.0. The power-law indexes that best reproduce the observed quantities are π = -0.45 ± 0.30 and κ = -1.0 ± 0.4. The period distribution that we obtain thus favours shorter period systems compared to an Öpik law (π = 0). The mass ratio distribution is slightly skewed towards low mass ratio systems but remains incompatible with a random sampling of a classical mass function (κ = -2.35). The binary fraction seems mostly uniform across the field of view and independent of the spectral types and luminosity classes. The binary fraction in the outer

  16. The VLT-FLAMES Tarantula Survey. XII. Rotational velocities of the single O-type stars

    Science.gov (United States)

    Ramírez-Agudelo, O. H.; Simón-Díaz, S.; Sana, H.; de Koter, A.; Sabín-Sanjulían, C.; de Mink, S. E.; Dufton, P. L.; Gräfener, G.; Evans, C. J.; Herrero, A.; Langer, N.; Lennon, D. J.; Maíz Apellániz, J.; Markova, N.; Najarro, F.; Puls, J.; Taylor, W. D.; Vink, J. S.

    2013-12-01

    Context. The 30 Doradus (30 Dor) region of the Large Magellanic Cloud, also known as the Tarantula nebula, is the nearest starburst region. It contains the richest population of massive stars in the Local Group, and it is thus the best possible laboratory to investigate open questions on the formation and evolution of massive stars. Aims: Using ground-based multi-object optical spectroscopy obtained in the framework of the VLT-FLAMES Tarantula Survey (VFTS), we aim to establish the (projected) rotational velocity distribution for a sample of 216 presumably single O-type stars in 30 Dor. The sample is large enough to obtain statistically significant information and to search for variations among subpopulations - in terms of spectral type, luminosity class, and spatial location - in the field of view. Methods: We measured projected rotational velocities, νesini, by means of a Fourier transform method and a profile fitting method applied to a set of isolated spectral lines. We also used an iterative deconvolution procedure to infer the probability density, P(νe), of the equatorial rotational velocity, νe. Results: The distribution of νesini shows a two-component structure: a peak around 80 kms-1 and a high-velocity tail extending up to ~600 kms-1. This structure is also present in the inferred distribution P(νe) with around 80% of the sample having 0 low-velocity peak is consistent with what has been found in other studies for late O- and early B-type stars. Conclusions: Most of the stars in our sample rotate with a rate less than 20% of their break-up velocity. For the bulk of the sample, mass loss in a stellar wind and/or envelope expansion is not efficient enough to significantly spin down these stars within the first few Myr of evolution. If massive-star formation results in stars rotating at birth with a large portion of their break-up velocities, an alternative braking mechanism, possibly magnetic fields, is thus required to explain the present

  17. [Determination of cotton content in cotton/ramie blended fabric by NIR spectra and variable selection methods].

    Science.gov (United States)

    Sun, Tong; Geng, Xiang; Liu, Mu-hua

    2014-12-01

    Rapid detection of textile fiber components is very important for production process of quality control, trading and market surveillance. The objective of this research was to assess cotton content in cotton/ramie blended fabric quickly by near infrared (NIR) spectrum technology and variable selection methods. Reflectance spectra of samples were acquired by a NIRFlex N-500 Fourier spectroscopy in the range of 4000~10,000 cm(-1), primary election of spectral range and pretreatment analysis were conducted first. Then, three variable selection methods such as UVE (uninformative variables elimination), SPA (successive projections algorithm) and CARS (competitive adaptive reweighted sampling) were used to select sensitive variables. After that, PLS (partial least squares) was used to develop calibration model for cotton content of cotton/ramie blended fabric, and the best calibration model was used to predict cotton content of samples in prediction set. The result indicates that range of 4052~8000 cm(-1) is optimal spectral range for cotton content modeling. CARS method is an efficient method to improve model performance, the correlation coefficient and root mean square error of CARS-PLS for calibration and prediction sets are 0.903, 0.749 and 8.01%, 12.93%, respectively. So NIR spectra combined with CARS method is feasible for assessing cotton content in cotton/ramie blended fabric, and CARS method can simplify model, improve model performance.

  18. VizieR Online Data Catalog: 1.1-2.4um spectra of 7 young M and L dwarfs (Manjavacas+, 2014)

    Science.gov (United States)

    Manjavacas, E.; Bonnefoy, M.; Schlieder, J. E.; Allard, F.; Rojo, P.; Goldman, B.; Chauvin, G.; Homeier, D.; Lodieu, N.; Henning, T.

    2014-02-01

    Our targets were observed with the Infrared Spectrometer And Array Camera (ISAAC) mounted on the Very Large Telescope (VLT) ath the UT3 telescope. The instrument was operated in low-resolution mode with the 0.3" slit at central wavelengths 1.25um, 1.65um, and 2.2um. This setup provides spectra with resolving powers of ~1700, 1600, and 1500 from 1.1-1.4um (J band), 1.42-1.82um (H band), and 1.82-2.5um (K band). (2 data files).

  19. High spectral resolution spectroscopy of the SiO fundamental lines in red giants and red supergiants with VLT/VISIR

    Science.gov (United States)

    Ohnaka, K.

    2014-01-01

    Context. The mass-loss mechanism in red giants and red supergiants is not yet understood well. The SiO fundamental lines near 8 μm are potentially useful for probing the outer atmosphere, which is essential for clarifying the mass-loss mechanism. However, these lines have been little explored until now. Aims: We present high spectral resolution spectroscopic observations of the SiO fundamental lines near 8.1 μm in 16 bright red giants and red supergiants. Our sample consists of seven normal (i.e., non-Mira) K-M giants (from K1.5 to M6.5), three Mira stars, three optically bright red supergiants, two dusty red supergiants, and the enigmatic object GCIRS3 near the Galactic center. Methods: Our program stars were observed between 8.088 μm and 8.112 μm with a spectral resolution of 30 000 using VLT/VISIR. Results: We detected SiO fundamental lines in all of our program stars except for GCIRS3. The SiO lines in normal K and M giants as well as optically bright (i.e., not dusty) red supergiants do not show P-Cyg profiles or blueshifts, which means the absence of systematic outflows in the SiO line forming region. We detected P-Cyg profiles in the SiO lines in the dusty red supergiants VY CMa and VX Sgr, with the latter object being a new detection. These SiO lines originate in the outflowing gas with the thermal dust continuum emission seen as the background. The outflow velocities of the SiO line forming region in VY CMa and VX Sgr are estimated to be 27 km s-1 and 17 km s-1, respectively. We derived basic stellar parameters (effective temperature, surface gravity, luminosity, and mass) for the normal K-M giants and optically bright red supergiants in our sample and compared the observed VISIR spectra with synthetic spectra predicted from MARCS photospheric models. Most of the SiO lines observed in the program stars warmer than ~3400 K are reasonably reproduced by the MARCS models, which allowed us to estimate the silicon abundance as well as the 28Si/29Si and 28Si

  20. Control spectra for Quito

    Science.gov (United States)

    Aguiar, Roberto; Rivas-Medina, Alicia; Caiza, Pablo; Quizanga, Diego

    2017-03-01

    The Metropolitan District of Quito is located on or very close to segments of reverse blind faults, Puengasí, Ilumbisí-La Bota, Carcelen-El Inca, Bellavista-Catequilla and Tangahuilla, making it one of the most seismically dangerous cities in the world. The city is divided into five areas: south, south-central, central, north-central and north. For each of the urban areas, elastic response spectra are presented in this paper, which are determined by utilizing some of the new models of the Pacific Earthquake Engineering Research Center (PEER) NGA-West2 program. These spectra are calculated considering the maximum magnitude that could be generated by the rupture of each fault segment, and taking into account the soil type that exists at different points of the city according to the Norma Ecuatoriana de la Construcción (2015). Subsequently, the recurrence period of earthquakes of high magnitude in each fault segment is determined from the physical parameters of the fault segments (size of the fault plane and slip rate) and the pattern of recurrence of type Gutenberg-Richter earthquakes with double truncation magnitude (Mmin and Mmax) is used.

  1. Meteors and meteorites spectra

    Science.gov (United States)

    Koukal, J.; Srba, J.; Gorková, S.; Lenža, L.; Ferus, M.; Civiš, S.; Knížek, A.; Kubelík, P.; Kaiserová, T.; Váňa, P.

    2016-01-01

    The main goal of our meteor spectroscopy project is to better understand the physical and chemical properties of meteoroids. Astrometric and spectral observations of real meteors are obtained via spectroscopic CCD video systems. Processed meteor data are inserted to the EDMOND database (European viDeo MeteOr Network Database) together with spectral information. The fully analyzed atmospheric trajectory, orbit and also spectra of a Leonid meteor/meteoroid captured in November 2015 are presented as an example. At the same time, our target is the systematization of spectroscopic emission lines for the comparative analysis of meteor spectra. Meteoroid plasma was simulated in a laboratory by laser ablation of meteorites samples using an (ArF) excimer laser and the LIDB (Laser Induced Dielectric Breakdown) in a low pressure atmosphere and various gases. The induced plasma emissions were simultaneously observed with the Echelle Spectrograph and the same CCD video spectral camera as used for real meteor registration. Measurements and analysis results for few selected meteorite samples are presented and discussed.

  2. VizieR Online Data Catalog: Velocities and photometry in Trumpler 20 (Donati+, 2014)

    Science.gov (United States)

    Donati, P.; Gaudin, Cantat; Bragaglia, A.; Friel, E.; Magrini, L.; Smiljanic, R.; Vallenari, A.; Tosi, M.; Sordo, R.; Tautvaisiene, G.; Blanco-Cuaresma, S.; Costado, M. T.; Geisler, D.; Klutsch, A.; Mowlavi, N.; Munoz, C.; San, Roman I.; Zaggia, S.; Gilmore, G.; Randich, S.; Bensby, T.; Flaccomio, E.; Koposov, S. E.; Korn, A. J.; Pancino, E.; Recio-Blanco, A.; Franciosini, E.; de Laverny, P.; Lewis, J.; Morbidelli, L.; Prisinzano, L.; Sacco, G.; Worley, C. C.; Hourihane, A.; Jofre, P.; Lardo, C.; Maiorca, E.

    2013-11-01

    We combined high quality photometry available in literature (Carraro et al., 2010AJ....140..954C, hereafter C10, and Platais et al., 2008, Cat. J/MNRAS/391/1482, hereafter P08) and the spectroscopic observations of the Gaia-ESO Survey to reevaluate the parameters of the open cluster Trumpler 20. 1370 star spectra, taken with UVES and GIRAFFE spectrograph at VLT/UT2, of both main sequence and red clump stars were exploited to estimate the radial velocity distribution of the cluster stars and select the most probable cluster members. 13 red clump stars observed with UVES were used to determine the cluster metallicity. With the improved information on metallicity and membership we used the photometric catalogues to estimate age, distance and average galactic reddening by means of the isochrone fitting method. We estimated the differential reddening on the cluster face and found to play a not negligible role on the CMD morphology. (2 data files).

  3. Nucleosynthesis in a Primordial Supernova: Carbon and Oxygen Abundances in SMSS J031300.36-670839.31

    CERN Document Server

    Bessell, Michael; Keller, Stefan; Frebel, Anna; Heger, Alexander; Casey, Andrew; Masseron, Thomas; Asplund, Martin; Jacobsen, Heather; Lind, Karin; Marino, Anna; Norris, John; Yong, David; Da Costa, Gary; Chan, Conrad; Magic, Zazralt; Schmidt, Brian; Tisserand, Patrick

    2015-01-01

    SMSS J031300.36-670839.3 (hereafter SM0313-6708) is a sub-giant halo star, with no detectable Fe lines and large overabundances of C and Mg relative to Ca. We obtained VLT-UVES spectra extending to 3060 Angstroms showing strong OH A-X band lines enabling an oxygen abundance to be derived. The OH A-X band lines in SM0313-6708 are much stronger than the CH C-X band lines. Spectrum synthesis fits indicate an [O/C] ratio of 0.02 +- 0.175. Our high S/N UVES data also enabled us to lower the Fe abundance limit to [Fe/H]{3D},NLTE < -7.52 (3 sigma). These data support our previous suggestion that the star formed from the iron-poor ejecta of a single massive star Population III supernova.

  4. Serial and subjective clustering on a verbal learning test (VLT) in children aged 5-15: the nature of subjective clustering.

    Science.gov (United States)

    Meijs, Celeste; Hurks, Petra; Rozendaal, Nico; Jolles, Jelle

    2013-01-01

    This study investigated which strategies children aged 5-15 years (N = 408) employ while performing a multitrial free recall test of semantically unrelated words. Serial clustering (i.e., a relatively passive strategy) is an index of the sequential consistency of recall order. Subjective clustering (i.e., a more active strategy) is based on similar word groupings in successive trials. Previously, Meijs et al. (2009) found that the level of (serial and subjective) clustering increases with age. At all ages, the level of serial clustering correlates positively with the ability to recall information on VLT trials. However, subjective clustering is more predictive of VLT performance than serial clustering after ≥ 3 trials, but only in children aged 8+. Knowledge on how children organize words (based on, for example, sound or meaning) and how this relates to developmental stage is still lacking. This study revealed that the level of subjective clustering is primarily determined by the position of words in a VLT list. More specifically, primacy (i.e., recall of words 1-3 of the VLT list - whether recalled in the same order or reversed) and recency (i.e., recall of words 14-15) effects primarily determine level subjective organization over successive trials. Thus, older children still organize words based on the serial position of the VLT list and are much less likely to organize them based on any other feature of the words, for example, sound or meaning. This indicates that the most important information to be learned needs to be presented first or last, even in older children and even with repeated presentations.

  5. The VIMOS VLT Deep Survey: Tracing the galaxy stellar mass assembly history over the last 8Gyr

    CERN Document Server

    Vergani, D; Pozzetti, L; Iovino, A; Franzetti, P; Garilli, B; Zamorani, G; MacCagni, D; Lamareille, F; Le Fèvre, O; Charlot, S; Contini, T; Bottini, D; Le Brun, V; Picat, J P; Scaramella, R; Tresse, L; Vettolani, G; Zanichelli, A; Adami, C; Arnouts, S; Bardelli, S; Bolzonella, M; Cappi, A; Ciliegi, P; Foucaud, S; Gavignaud, I; Guzzo, L; Ilbert, O; McCracken, H J; Marano, B; Marinoni, C; Mazure, A; Meneux, B; Merighi, R; Paltani, S; Pellò, R; Pollo, A; Radovich, M; Zucca, E; Bondi, M; Bongiorno, A; Brinchmann, J; Cucciati, O; De la Torre, S; Gregorini, L; Mellier, Y; Merluzzi, P; Temporin, S; Walcher, C J

    2007-01-01

    We select a mass limited sample of 4048 objects from the VIMOS VLT Deep Survey (VVDS) in the redshift interval 0.51.3) that continues efficiently down to the local Universe. The underlying stellar ages of LT galaxies apparently do not show evolution, most likely as a result of a continuous and efficient formation of new stars. The activity and efficiency of forming stars are mechanisms depending on galaxy stellar mass, resulting in a largely inefficient stellar mass assembly in massive systems up to z=1.3. The concepts of downsizing in star formation and in mass (or archaeological downsizing) describe a single s cenario which has a top-down evolutionary pattern in star formation as well as in mass assembly. The role of (dry) merging events seems to be only marginal at z<1.3, as our estimated efficiency in stellar mass assembly can account for the progressive accumulation of observed passively evolving galaxies.

  6. VLT FORS2 comparative transmission spectroscopy: Detection of Na in the atmosphere of WASP-39b from the ground

    CERN Document Server

    Nikolov, Nikolay; Gibson, Neale P; Fortney, J J; Evans, Thomas M; Barstow, Joanna K; Kataria, Tiffany; Wilson, Paul A

    2016-01-01

    We present transmission spectroscopy of the warm Saturn-mass exoplanet WASP-39b made with the Very Large Telescope (VLT) FOcal Reducer and Spectrograph (FORS2) across the wavelength range 411-810nm. The transit depth is measured with a typical precision of 240 parts per million (ppm) in wavelength bins of 10nm on a V = 12.1 magnitude star. We detect the sodium absorption feature (3.2-sigma) and find evidence for potassium. The ground-based transmission spectrum is consistent with Hubble Space Telescope (HST) optical spectroscopy, strengthening the interpretation of WASP-39b having a largely clear atmosphere. Our results demonstrate the great potential of the recently upgraded FORS2 spectrograph for optical transmission spectroscopy, obtaining HST-quality light curves from the ground.

  7. Particle Accelerators in the Hot Spots of the Radio Galaxy 3C445 Imaged With the VLT

    CERN Document Server

    Prieto, M A; Mack, K H; Brunetti, Gianfranco; Mack, Karl-Heinz

    2002-01-01

    Hot spots (HSs) are regions of enhanced radio emission produced by supersonic jets at the tip of the radio lobes of powerful radiosources. Obtained with the Very Large Telescope (VLT), images of the HSs in the radio galaxy 3C445 show bright knots embedded in diffuse optical emission distributed along the post shock region created by the impact of the jet into the intergalactic medium. The observations reported here confirm that relativistic electrons are accelerated by Fermi-I acceleration processes in HSs. Furthermore, both the diffuse emission tracing the rims of the front shock and the multiple knots demonstrate the presence of additional continuous re-acceleration processes of electrons (Fermi-II).

  8. Performance of the VLT Planet Finder SPHERE I. Photometry and astrometry precision with IRDIS and IFS in laboratory

    CERN Document Server

    Zurlo, A; Mesa, D; Gratton, R; Moutou, C; Langlois, M; Claudi, R U; Pueyo, L; Boccaletti, A; Baruffolo, A; Beuzit, J -L; Costille, A; Desidera, S; Dohlen, K; Feldt, M; Fusco, T; Henning, T; Kasper, M; Martinez, P; Moeller-Nilsson, O; Mouillet, D; Pavlov, A; Puget, P; Sauvage, J -F; Turatto, M; Udry, S; Vakili, F; Waters, R; Wildi, R F

    2014-01-01

    The new planet finder for the Very Large Telescope (VLT), the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE), just had its first light in Paranal. A dedicated instrument for the direct detection of planets, SPHERE, is composed of a polametric camera in visible light, the Zurich IMager POLarimeter (ZIMPOL), and two near-infrared sub-systems: the Infra-Red Dual-beam Imager and Spectrograph (IRDIS), a multi-purpose camera for imaging, polarimetry, and long-slit spectroscopy, and the integral field spectrograph (IFS), an integral field spectrograph. We present the results obtained from the analysis of data taken during the laboratory integration and validation phase, after the injection of synthetic planets. Since no continuous field rotation could be performed in the laboratory, this analysis presents results obtained using reduction techniques that do not use the angular differential imaging (ADI) technique. To perform the simulations, we used the instrumental point spread function (PSF) and mod...

  9. The VLT-FLAMES Tarantula Survey VI: Evidence for rotation of the young massive cluster R136

    CERN Document Server

    Hénault-Brunet, V; Evans, C J; Sana, H; Bastian, N; Apellániz, J Maíz; Taylor, W D; Markova, N; Bressert, E; de Koter, A; van Loon, J Th

    2012-01-01

    Although it has important ramifications for both the formation of star clusters and their subsequent dynamical evolution, rotation remains a largely unexplored characteristic of young star clusters (few Myr). Using multi-epoch spectroscopic data of the inner regions of 30 Doradus in the Large Magellanic Cloud (LMC) obtained as part of the VLT-FLAMES Tarantula Survey, we search for rotation of the young massive cluster R136. From the radial velocities of 36 apparently single O-type stars within a projected radius of 10 pc from the centre of the cluster, we find evidence, at the 95% confidence level, for rotation of the cluster as a whole. We use a maximum likelihood method to fit simple rotation curves to our data and find a typical rotational velocity of ~3 km/s. When compared to the low velocity dispersion of R136, our result suggests that star clusters may form with at least ~20% of the kinetic energy in rotation.

  10. The VLT-FLAMES Tarantula Survey. XV. VFTS\\,822: a candidate Herbig B[e] star at low metallicity

    CERN Document Server

    Kalari, V M; Dufton, P L; Evans, C J; Dunstall, P R; Sana, H; Clark, J S; Ellerbroek, L; de Koter, A; Lennon, D J; Taylor, W D

    2014-01-01

    We report the discovery of the B[e] star VFTS 822 in the 30 Doradus star-forming region of the Large Magellanic Cloud, classified by optical spectroscopy from the VLT-FLAMES Tarantula Survey and complementary infrared photometry. VFTS 822 is a relatively low-luminosity (log $L$ = 4.04 $\\pm$ 0.25 $L_{\\odot}$) B8[e] star. In this Letter, we evaluate the evolutionary status of VFTS 822 and discuss its candidacy as a Herbig B[e] star. If the object is indeed in the pre-main sequence phase, it would present an exciting opportunity to measure mass accretion rates at low metallicity spectroscopically, to understand the effect of metallicity on accretion rates.

  11. Polarimetry in Planetary Science—A Step Forward with the VLT and a Need for the ELTs

    Science.gov (United States)

    Boehnhardt, H.; Tozzi, G. P.; Sterzik, M.; Bagnulo, S.; Kolokolova, L.; Muinonen, K.

    2009-09-01

    We present a brief review of polarimetric measurements of solar system objects, both linear and circular, obtained with the FORS1 instrument at the Very Large Telescope VLT over the past years. A number of first and new results have been obtained by using this unique observing mode at an 8 m class telescope, among them polarimetry of faint planetary bodies like near-Earth asteroids, Kuiper Belt objects and cometary nuclei, spectropolarimetry of cometary coma material and of the Earthshine of the Moon (in order to verify that life exists on Earth!). We outline the science cases for planetary polarimetry at a future Extremely Large Telescope ELT and provide high level requirements for polarimetric equipment to be used at the ELTs for the study of the science cases described.

  12. Ground-based astrometry with wide field imagers. V. Application to near-infrared detectors: HAWK-I@VLT/ESO

    Science.gov (United States)

    Libralato, M.; Bellini, A.; Bedin, L. R.; Piotto, G.; Platais, I.; Kissler-Patig, M.; Milone, A. P.

    2014-03-01

    High-precision astrometry requires accurate point-spread function modeling and accurate geometric-distortion corrections. This paper demonstrates that it is possible to achieve both requirements with data collected at the high acuity wide-field K-band imager (HAWK-I), a wide-field imager installed at the Nasmyth focus of UT4/VLT ESO 8 m telescope. Our final astrometric precision reaches ~3 mas per coordinate for a well-exposed star in a single image with a systematic error less than 0.1 mas. We constructed calibrated astro-photometric catalogs and atlases of seven fields: the Baade's window, NGC 6656, NGC 6121, NGC 6822, NGC 6388, NGC 104, and the James Webb Space Telescope calibration field (in the Large Magellanic Cloud). We make these catalogs and images electronically available to the community. Furthermore, as a demonstration of the efficacy of our approach, we combined archival material taken with the optical wide-field imager at the MPI/ESO 2.2 m with HAWK-I observations. We showed that we are able to achieve an excellent separation between cluster members and field objects for NGC 6656 and NGC 6121 with a time base-line of about 8 years. Using both HST and HAWK-I data, we also study the radial distribution of the SGB populations in NGC 6656 and conclude that the radial trend is flat within our uncertainty. We also provide membership probabilities for most of the stars in NGC 6656 and NGC 6121 catalogs and estimate membership for the published variable stars in these two fields. Catalogs, fortran code, and distortion maps 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/563/A80Based on observations with the 8 m VLT ESO telescope.

  13. Sequencing BPS Spectra

    CERN Document Server

    Gukov, Sergei; Saberi, Ingmar; Stosic, Marko; Sulkowski, Piotr

    2015-01-01

    This paper provides both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explain from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincar\\'e polynomials in numerous examples. Among these structural properties is a novel "sliding" property, which can be explained by using (refined) modular $S$-matrix. This leads to the identifi...

  14. s-process Enrichment in the Planetary Nebula NGC 3918

    CERN Document Server

    García-Rojas, J; Luridiana, V; Sterling, N C; Morisset, C

    2014-01-01

    We present deep, high-resolution (R~40000) UVES at VLT spectrophotometric data of the planetary nebula NGC 3918. This is one of the deepest spectra ever taken of a planetary nebula. We have identified and measured more than 700 emission lines and, in particular, we have detected very faint lines of several neutron-capture elements (s-process elements: Kr, Xe and Rb) that enable us to compute their chemical abundances with unprecedented accuracy, thus constraining the efficiency of the s-process and convective dredge-up.

  15. A window on the efficiency of the s-process in AGB stars: chemical abundances of n-capture elements in the planetary nebula NGC 3918

    CERN Document Server

    Madonna, S; Luridiana, V; Sterling, N C; Morisset, C

    2015-01-01

    The chemical content of the planetary nebula NGC 3918 is investigated through deep, high-resolution (R~40000) UVES at VLT spectrophotometric data. We identify and measure more than 750 emission lines, making ours one of the deepest spectra ever taken for a planetary nebula. Among these lines we detect very faint lines of several neutron-capture elements (Se, Kr, Rb, and Xe), which enable us to compute their chemical abundances with unprecedented accuracy, thus constraining the efficiency of the s-process and convective dredge-up in the progenitor star of NGC 3918.

  16. The ESO Large Programme First Stars

    CERN Document Server

    Bonifacio, P; Andrievsky, S; Barbuy, B; Beers, T C; Caffau, E; Cayrel, R; Depagne, E; François, P; Hernandez, J I Gonzalez; Hansen, C J; Herwig, F; Hill, V; Korotin, S A; Ludwig, H -G; Molaro, P; Nordström, B; Plez, B; Primas, F; Sivarani, T; Spite, F; Spite, M

    2008-01-01

    In ESO period 65 (April-September 2000) the large programme 165.N-0276, led by Roger Cayrel, began making use of UVES at the Kueyen VLT telescope. Known within the Team and outside as ``First Stars'', it was aimed at obtaining high resolution, high signal-to-noise ratio spectra in the range 320 nm -- 1000 nm for a large sample of extremely metal-poor (EMP) stars identified from the HK objective prism survey.In this contribution we highlight the main results of the large programme.

  17. First Images and Spectra from ISAAC on UT1

    Science.gov (United States)

    1998-11-01

    New VLT Instrument Delivers Spectacular Infrared Views of the Southern Sky The VLT Infrared Spectrometer And Array Camera (ISAAC) [1] was installed at the first 8.2-m VLT Unit Telescope (UT1) on November 14, 1998, cf. ESO PR Photos 42a-h/98. ISAAC is the second major VLT instrument to be installed at the VLT and the first to be fully designed and developed at ESO within its Instrumentation Division. Following evacuation of its large vacuum vessel, cooling to cryogenic temperature and alignment with the telescope according to the planned schedule, it successfully achieved technical first light during the night between November 16 and 17, 1998. ESO PR Photo 46a/98 ESO PR Photo 46a/98 [JPEG: 800 x 847 pix - 432k] [High-Res - JPEG: 3000 x 3175 pix - 2.9Mb] PR Photo 46a/98 shows ISAAC as it is now mounted at the UT1 Nasmyth B adaptor-rotator (right; blue colour). The co-rotator system (left) through which the various cables are fed to the instrument, is also well visible. (Photo obtained on November 16, 1998). The first focus tests on stars yielded images of excellent sharpness, around 0.45 arcsec full-width-half-maximum (FWHM). During the following nights, even better images, as small as 0.25 arcsec in relatively short exposures, were obtained, testifying to the quality of the site as well as the optical quality of both the telescope and instrument. Observations were executed using the new VLT Control and Data Flow Systems which are driven by Observation Blocks that define all details of the required astronomical exposures. In addition to direct images in various infrared colours (selected with different optical filters), spectroscopic observations were also made during the first few nights of operation. This Press Release is accompanied by several images and spectra which illustrate some of the exceptional new astronomical capabilities offered by this instrument. Star-Forming Region RCW38 in the Milky Way ESO PR Photo 46b/98 ESO PR Photo 46b/98 [Preview - JPEG: 800 x

  18. CRIRES-POP: A library of high resolution spectra in the near-infrared

    CERN Document Server

    Lebzelter, T; Uttenthaler, S; Ramsay, S; Hartman, H; Nieva, M -F; Przybilla, N; Smette, A; Wahlgren, G M; Wolff, B; Hussain, G A J; Kaeufl, H U; Seemann, U

    2012-01-01

    New instrumental capabilities and the wealth of astrophysical information extractable from the near-infrared wavelength region have led to a growing interest in the field of high resolution spectroscopy at 1-5 mu. We aim to provide a library of observed high-resolution and high signal-to-noise-ratio near-infrared spectra of stars of various types throughout the Hertzsprung-Russell diagram. This is needed for the exploration of spectral features in this wavelength range and for comparison of reference targets with observations and models. High quality spectra were obtained using the CRIRES near-infrared spectrograph at ESO's VLT covering the range from 0.97 to 5.3 mu at high spectral resolution. Accurate wavelength calibration and correction for of telluric lines were performed by fitting synthetic transmission spectra for the Earth's atmosphere to each spectrum individually. We describe the observational strategy and the current status and content of the library which includes 13 objects. The first examples o...

  19. Sequencing BPS spectra

    Science.gov (United States)

    Gukov, Sergei; Nawata, Satoshi; Saberi, Ingmar; Stošić, Marko; Sułkowski, Piotr

    2016-03-01

    This paper provides both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explain from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincaré polynomials in numerous examples. Among these structural properties is a novel "sliding" property, which can be explained by using (refined) modular S-matrix. This leads to the identification of modular transformations in Chern-Simons theory and 3d {N}=2 theory via the 3d/3d correspondence. Lastly, we introduce the notion of associated varieties as classical limits of recursion relations of colored superpolynomials of links, and study their properties.

  20. Non-Gaussian Spectra

    CERN Document Server

    Ferreira, P G; Ferreira, Pedro G.; Magueijo, Joao

    1997-01-01

    Gaussian cosmic microwave background skies are fully specified by the power spectrum. The conventional method of characterizing non-Gaussian skies is to evaluate higher order moments, the n-point functions and their Fourier transforms. We argue that this method is inefficient, due to the redundancy of information existing in the complete set of moments. In this paper we propose a set of new statistics or non-Gaussian spectra to be extracted out of the angular distribution of the Fourier transform of the temperature anisotropies in the small field limit. These statistics complement the power spectrum and act as localization, shape, and connectedness statistics. They quantify generic non-Gaussian structure, and may be used in more general image processing tasks. We concentrate on a subset of these statistics and argue that while they carry no information in Gaussian theories they may be the best arena for making predictions in some non-Gaussian theories. As examples of applications we consider superposed Gaussi...

  1. Sequencing BPS spectra

    Energy Technology Data Exchange (ETDEWEB)

    Gukov, Sergei [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Max-Planck-Institut für Mathematik,Vivatsgasse 7, D-53111 Bonn (Germany); Nawata, Satoshi [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Centre for Quantum Geometry of Moduli Spaces, University of Aarhus,Nordre Ringgade 1, DK-8000 (Denmark); Saberi, Ingmar [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Stošić, Marko [CAMGSD, Departamento de Matemática, Instituto Superior Técnico,Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Mathematical Institute SANU,Knez Mihajlova 36, 11000 Belgrade (Serbia); Sułkowski, Piotr [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Faculty of Physics, University of Warsaw,ul. Pasteura 5, 02-093 Warsaw (Poland)

    2016-03-02

    This paper provides both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explain from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincaré polynomials in numerous examples. Among these structural properties is a novel “sliding” property, which can be explained by using (refined) modular S-matrix. This leads to the identification of modular transformations in Chern-Simons theory and 3d N=2 theory via the 3d/3d correspondence. Lastly, we introduce the notion of associated varieties as classical limits of recursion relations of colored superpolynomials of links, and study their properties.

  2. Análise da qualidade de vida de portadores de uveítes de causas infecciosas e não infecciosas pelo questionário NEI-VFQ-25 Analysis of the life quality of infectious and non-infectious patients with uveitis using the NEI-VFQ-25 questionnaire

    Directory of Open Access Journals (Sweden)

    Paula Resende Aquino de Assis Pereira Mello

    2008-12-01

    Full Text Available OBJETIVO: Avaliar a qualidade de vida dos pacientes portadores de uveítes infecciosas e não infecciosas avaliados no setor de uveíte do serviço de oftalmologia do Hospital Universitário Clementino Fraga Filho - UFRJ, por meio da aplicação do questionário NEI-VFQ-25, de modo a esclarecer melhor a importância do diagnóstico e tratamento das uveítes, assim como suas conseqüências na função visual e social dos pacientes. MÉTODOS: Estudo prospectivo composto de 30 pacientes com uveítes que foram divididos em dois grupos conforme a etiologia, infecciosa e não infecciosa, tendo sido aplicado duas vezes em cada paciente o questionário NEI-VFQ-25 que avalia a qualidade de vida relacionada à saúde geral e visual. RESULTADOS: A toxoplasmose foi a principal causa de uveíte infecciosa, enquanto a não infecciosa foi a síndrome de Vogt-Koyanagi-Harada. Quanto à qualidade de vida, a saúde geral é melhor no grupo de causa infecciosa, sendo que a saúde ocular é regular nos dois grupos. Apesar do déficit visual não provocar grandes distúrbios e restrições sociais, ambos os grupos apresentam comprometimento emocional importante, sendo que no grupo de causa não infecciosa, esse comprometimento gera grau maior de dependência para a realização de tarefas do cotidiano. CONCLUSÃO: A maior dependência social e na realização de atividades do dia-a-dia no grupo de uveítes de causa não infecciosas, se explica pelo modo crônico e recidivante dessas afecções, o que leva à qualidade de vida inferior se comparada ao outro grupo.PURPOSE: To evaluate the life quality of patients with infectious and non-infectious uveitis evaluated at the uveitis service of the Hospital Universitário Clementino Fraga Filho-UFRJ, using the NEI-VFQ-25 questionnaire in order to clarify the importance of uveitis diagnosis and treatment as well as its consequences to visual and social functions of the patients. METHODS: Prospective study of 30 patients

  3. The Panchromatic High-Resolution Spectroscopic Survey of Local Group Star Clusters - I. General Data Reduction Procedures for the VLT/X-shooter UVB and VIS arm

    CERN Document Server

    Schönebeck, Frederik; Pasquali, Anna; Grebel, Eva K; Kissler-Patig, Markus; Kuntschner, Harald; Lyubenova, Mariya; Perina, Sibilla

    2014-01-01

    Our dataset contains spectroscopic observations of 29 globular clusters in the Magellanic Clouds and the Milky Way performed with VLT/X-shooter. Here we present detailed data reduction procedures for the VLT/X-shooter UVB and VIS arm. These are not restricted to our particular dataset, but are generally applicable to different kinds of X-shooter data without major limitation on the astronomical object of interest. The packaged pipeline provided by ESO (v1.5.0) performs well and reliably for the wavelength calibration and the associated rectification procedure, yet we find several weaknesses in the reduction cascade that are addressed with additional calibration steps, such as bad pixel interpolation, flat fielding, and slit illumination corrections. Furthermore, the instrumental PSF is analytically modeled and used to reconstruct flux losses at slit transit and for optimally extracting point sources. Regular observations of spectrophotometric standard stars allow us to detect instrumental variability, which n...

  4. Scientific Objectives and Design Study of an Adaptive Optics Visual Echelle Spectrograph and Imager Coronograph (AVES-IMCO) for the NAOS Visitor Focus at the VLT

    Science.gov (United States)

    Pallavicini, Roberto; Zerbi, Filippo; Beuzit, Jean-Luc; Bonanno, Giovanni; Bonifacio, Piercarlo; Comari, Maurizio; Conconi, Paolo; Delabre, Bernard; Franchini, Mariagrazia; Marcantonio, Paolo Di; Lagrange, Anne-Marie; Mazzoleni, Ruben; Molaro, Paolo; Pasquini, Luca; Santin, Paolo

    We present the scientific case for an Adaptive Optics Visual Echelle Spectrograph and Imager Coronograph (AVES-IMCO) that we propose as a visitor instrument for the secondary port of NAOS at the VLT. We show that such an instrument would be ideal for intermediate resolution (R=16,000) spectroscopy of faint sky-limited objects down to a magnitude of V=24.0 and will complement very effectively the near-IR imaging capabilities of CONICA. We present examples of science programmes that could be carried out with such an instrument and which cannot be addressed with existing VLT instruments. We also report on the result of a two-year design study of the instrument, with specific reference to its use as parallel instrument of NAOS.

  5. 3D shape of asteroid (6) Hebe from VLT/SPHERE imaging: Implications for the origin of ordinary H chondrites

    Science.gov (United States)

    Marsset, M.; Carry, B.; Dumas, C.; Hanuš, J.; Viikinkoski, M.; Vernazza, P.; Müller, T. G.; Delbo, M.; Jehin, E.; Gillon, M.; Grice, J.; Yang, B.; Fusco, T.; Berthier, J.; Sonnett, S.; Kugel, F.; Caron, J.; Behrend, R.

    2017-08-01

    Context. The high-angular-resolution capability of the new-generation ground-based adaptive-optics camera SPHERE at ESO VLT allows us to assess, for the very first time, the cratering record of medium-sized (D 100-200 km) asteroids from the ground, opening the prospect of a new era of investigation of the asteroid belt's collisional history. Aims: We investigate here the collisional history of asteroid (6) Hebe and challenge the idea that Hebe may be the parent body of ordinary H chondrites, the most common type of meteorites found on Earth ( 34% of the falls). Methods: We observed Hebe with SPHERE as part of the science verification of the instrument. Combined with earlier adaptive-optics images and optical light curves, we model the spin and three-dimensional (3D) shape of Hebe and check the consistency of the derived model against available stellar occultations and thermal measurements. Results: Our 3D shape model fits the images with sub-pixel residuals and the light curves to 0.02 mag. The rotation period (7.274 47 h), spin (ECJ2000 λ, β of 343°, +47°), and volume-equivalent diameter (193 ± 6 km) are consistent with previous determinations and thermophysical modeling. Hebe's inferred density is 3.48 ± 0.64 g cm-3, in agreement with an intact interior based on its H-chondrite composition. Using the 3D shape model to derive the volume of the largest depression (likely impact crater), it appears that the latter is significantly smaller than the total volume of close-by S-type H-chondrite-like asteroid families. Conclusions: Our results imply that (6) Hebe is not the most likely source of H chondrites. Over the coming years, our team will collect similar high-precision shape measurements with VLT/SPHERE for 40 asteroids covering the main compositional classes, thus providing an unprecedented dataset to investigate the origin and collisional evolution of the asteroid belt. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory

  6. VLT/XSHOOTER & Subaru/MOIRCS Spectroscopy of HUDF-YD3: No Evidence for Lyman-alpha Emission at z=8.55

    CERN Document Server

    Bunker, Andrew J; Wilkins, Stephen M; Stanway, Elizabeth R; Lorenzoni, Silvio; Lacy, Mark; Jarvis, Matt J; Hickey, Samantha

    2013-01-01

    We present spectroscopic observations with VLT/XSHOOTER and Subaru/MOIRCS of a relatively bright Y-band drop-out galaxy in the Hubble Ultra Deep Field, first selected by Bunker et al. (2010), McLure et al. (2010) and Bouwens et al. (2010) to be a likely z~8-9 galaxy on the basis of its colours in the HST ACS and WFC3 images. This galaxy, HUDF.YD3 (also known as UDFy-38135539) has been targetted for VLT/SINFONI integral field spectroscopy by Lehnert et al. (2010), who published a candidate Lyman-alpha emission line at z=8.55 from this source. In our independent spectroscopy using two different infrared spectrographs (5 hours with VLT/XSHOOTER and 11 hours with Subaru/MOIRCS) we are unable to reproduce this line. We do not detect any emission line at the spectral and spatial location reported in Lehnert et al. (2010), despite the expected signal in our combined MOIRCS & XSHOOTER data being 5-sigma. The line emission also seems to be ruled out by the faintness of this object in recently extremely deep F105W ...

  7. ZELDA, a Zernike wavefront sensor for the fine measurement of quasi-static aberrations in coronagraphic systems: concept studies and results with VLT/SPHERE

    Science.gov (United States)

    N'Diaye, M.; Vigan, A.; Dohlen, K.; Sauvage, J.-F.; Caillat, A.; Costille, A.; Girard, J. H. V.; Beuzit, J.-L.; Fusco, T.; Blanchard, P.; Le Merrer, J.; Le Mignant, D.; Madec, F.; Moreaux, G.; Mouillet, D.; Puget, P.; Zins, G.

    2016-07-01

    The high-contrast imaging instruments VLT/SPHERE and GPI have been routinely observing gas giant planets, brown dwarfs, and debris disks around nearby stars since 2013-2014. In these facilities, low-wind effects or differential aberrations between the extreme Adaptive Optics sensing path and the science path represent critical limitations for the observation of exoplanets orbiting their host star with a contrast ratio larger than 106 at small separations. To circumvent this problem, we proposed ZELDA, a Zernike wavefront sensor to measure these quasistatic aberrations at a nanometric level. A prototype was installed on VLT/SPHERE during its integration in Chile. We recently performed measurements on an internal source with ZELDA in the presence of Zernike or Fourier modes introduced with the deformable mirror of the instrument. In this communication, we present the results of our experiment and report on the contrast gain obtained with a first ZELDA-based wavefront correction. We finally discuss the suitability of such a solution for a possible upgrade of VLT/SPHERE and for its use with future E-ELT instruments or space missions with high-contrast capabilities (e.g. WFIRST-AFTA, HDST).

  8. Coupling MOAO with Integral Field Spectroscopy: specifications for the VLT and the E-ELT

    CERN Document Server

    Puech, M; Lehnert, M; Neichel, B; Fusco, T; Rosati, P; Cuby, J -G; Rousset, G

    2008-01-01

    [Abridged] We have developed an end-to-end simulation to specify the science requirements of a MOAO-fed integral field spectrograph on either an 8m or 42m telescope. Our simulations re-scales observations of local galaxies or results from numerical simulations of disk or interacting galaxies. For the current analysis, we limit ourselves to a local disk galaxy which exhibits simple rotation and a simulation of a merger. We have attempted to generalize our results by introducing the simple concepts of "PSF contrast" which is the amount of light polluting adjacent spectra which we find drives the smallest EE at a given spatial scale. The choice of the spatial sampling is driven by the "scale-coupling", i.e., the relationship between the IFU pixel scale and the size of the features that need to be recovered by 3D spectroscopy in order to understand the nature of the galaxy and its substructure. Because the dynamical nature of galaxies are mostly reflected in their large-scale motions, a relatively coarse spatial ...

  9. VLT Spectropolarimetry of the Type Ia SN2005ke - A step towards understanding subluminous events

    CERN Document Server

    Patat, F; Baade, D; Maund, J R; Wang, L; Wheeler, J C

    2012-01-01

    We performed optical spectropolarimetric observations of the subluminous Type Ia SN2005ke at 3 epochs (days -8, -7, and +76). The explosion properties are derived by comparing the data to explosion and radiation transfer models. The SN shows polarimetric properties that are very similar to the only other subluminous event for which spectropolarimetry is available, i.e. SN1999by. The data present a very marked dominant axis, which is shared by both the continuum and lines such as SiII 6355, suggesting that the relatively large, global asymmetry is common to the photosphere and the line-forming region. The maximum polarization degree observed in the SiII 6355 absorption reaches 0.39+/-0.08%. At variance with what is seen in core-normal Type Ia, SN2005ke displays significant continuum polarization, which grows from the blue to the red and peaks at about 7000 A, reaching ~0.7%. The properties of the polarization and flux spectra can be understood within the framework of a subluminous delayed-detonation (DD), or p...

  10. VLT X-shooter spectroscopy of the nearest brown dwarf binary

    CERN Document Server

    Lodieu, N; Rebolo, R; Bejar, V J S; Pavlenko, Y; Perez-Garrido, A

    2015-01-01

    The aim of the project is to characterise both components of the nearest brown dwarf sytem to the Sun, WISE J104915.57-531906.1 (=Luhman16AB) at optical and near-infrared wavelengths. We obtained high signal-to-noise intermediate-resolution (R~6000-11000) optical (600-1000 nm) and near-infrared (1000-2480nm) spectra of each component of Luhman16AB, the closest brown dwarf binary to the Sun, with the X-Shooter instrument on the Very Large Telescope. We classify the primary and secondary of the Luhman16 system as L6-L7.5 and T0+/-1, respectively, in agreement with previous measurements published in the literature. We present measurements of the lithium pseudo-equivalent widths, which appears of similar strength on both components (8.2+/-1.0 Angstroms and 8.4+/-1.5 Angstroms for the L and T components, respectively). The presence of lithium (Lithium 7) in both components imply masses below 0.06 Msun while comparison with models suggests lower limits of 0.04 Msun. The detection of lithium in the T component is th...

  11. VLT spectroscopy of the Black Hole Candidate Swift J1357.2-0933 in Quiescence

    CERN Document Server

    Torres, M A P; Miller-Jones, J C A; Steeghs, D; Repetto, S; Wu, Jianfeng

    2015-01-01

    We present time-resolved optical spectroscopy of the counterpart to the high-inclination black hole low-mass X-ray binary Swift J1357.2-0933 in quiescence. Absorption features from the mass donor star were not detected. Instead the spectra display prominent broad double-peaked Halpha emission and weaker HeI emission lines. From the Halpha peak-to-peak separation we constrain the radial velocity semi-amplitude of the donor star to > 789 km/s. Further analysis through radial velocity and equivalent width measurements indicates that the Halpha line is free of variability due to S-wave components or disc eclipses. From our data and previous observations during outburst, we conclude that long-term radial velocity changes ascribed to a precessing disc were of low amplitude or not present. This implies that the centroid position of the line should closely represent the systemic radial velocity. Using the derived systemic velocity of -150 km/s and the best available limits on the source distance, we infer that the bl...

  12. A Combined VLT and Gemini Study of the Atmosphere of the Directly-Imaged Planet, beta Pictoris b

    CERN Document Server

    Currie, Thayne; Madhusudhan, Nikku; Fukagawa, Misato; Girard, Julien H; Dawson, Rebekah; Murray-Clay, Ruth; Kenyon, Scott; Kuchner, Marc; Matsumura, Soko; Jayawardhana, Ray; Chambers, John; Bromley, Ben

    2013-01-01

    We analyze new/archival VLT/NaCo and Gemini/NICI high-contrast imaging of the young, self-luminous planet $\\beta$ Pictoris b in seven near-to-mid IR photometric filters, using advanced image processing methods to achieve high signal-to-noise, high precision measurements. While $\\beta$ Pic b's near-IR colors mimick that of a standard, cloudy early-to-mid L dwarf, it is overluminous in the mid-infrared compared to the field L/T dwarf sequence. Few substellar/planet-mass objects -- i.e. $\\kappa$ And b and 1RXJ 1609B -- match $\\beta$ Pic b's $JHK_{s}L^\\prime$ photometry, and its 3.1 $\\mu m$ and 5 $\\mu m$ photometry are particularly difficult to reproduce. Atmosphere models adopting cloud prescriptions and large ($\\sim$ 60 $\\mu m$) dust grains fail to reproduce the $\\beta$ Pic b spectrum. However, models incorporating thick clouds similar to those found for HR 8799 bcde but also with small (a few microns) modal particle sizes yield fits consistent with the data within uncertainties. Assuming solar abundance models...

  13. Lyman-\\alpha{} Emitters in the context of hierarchical galaxy formation: predictions for VLT/MUSE surveys

    CERN Document Server

    Garel, Thibault; Blaizot, Jérémy

    2015-01-01

    The VLT Multi Unit Spectroscopic Explorer (MUSE) integral-field spectrograph can detect Ly\\alpha{} emitters (LAE) in the redshift range $2.8 \\lesssim z \\lesssim 6.7$ in a homogeneous way. Ongoing MUSE surveys will notably probe faint Ly\\alpha{} sources that are usually missed by current narrow-band surveys. We provide quantitative predictions for a typical wedding-cake observing strategy with MUSE based on mock catalogs generated with a semi-analytic model of galaxy formation coupled to numerical Ly\\alpha{} radiation transfer models in gas outflows. We expect $\\approx$ 1500 bright LAEs ($F_{Ly\\alpha}$ $\\gtrsim$ $10^{-17}$ erg s$^{-1}$ cm$^{-2}$) in a typical Shallow Field (SF) survey carried over $\\approx$ 100 arcmin$^2$, and $\\approx$ 2,000 sources as faint as $10^{-18}$ erg s$^{-1}$ cm$^{-2}$ in a Medium-Deep Field (MDF) survey over 10 arcmin$^2$. In a typical Deep Field (DF) survey of 1 arcmin$^2$, we predict that $\\approx$ 500 extremely faint LAEs ($F_{Ly\\alpha}$ $\\gtrsim$ $4 \\times 10^{-19}$ erg s$^{-1}$...

  14. Validation through simulations of a C_n^2 profiler for the ESO/VLT Adaptive Optics Facility

    Science.gov (United States)

    Garcia-Rissmann, A.; Guesalaga, A.; Kolb, J.; Le Louarn, M.; Madec, P.-Y.; Neichel, B.

    2015-04-01

    The Adaptive Optics Facility (AOF) project envisages transforming one of the VLT units into an adaptive telescope and providing its ESO (European Southern Observatory) second generation instruments with turbulence-corrected wavefronts. For MUSE and HAWK-I this correction will be achieved through the GALACSI and GRAAL AO modules working in conjunction with a 1170 actuators deformable secondary mirror (DSM) and the new Laser Guide Star Facility (4LGSF). Multiple wavefront sensors will enable GLAO (ground layer adaptive optics) and LTAO (laser tomography adaptive optics) capabilities, whose performance can greatly benefit from a knowledge about the stratification of the turbulence in the atmosphere. This work, totally based on end-to-end simulations, describes the validation tests conducted on a C_n^2 profiler adapted for the AOF specifications. Because an absolute profile calibration is strongly dependent on a reliable knowledge of turbulence parameters r0 and L0, the tests presented here refer only to normalized output profiles. Uncertainties in the input parameters inherent to the code are tested as well as the profiler response to different turbulence distributions. It adopts a correction for the unseen turbulence, critical for the GRAAL mode, and highlights the effects of masking out parts of the corrected wavefront on the results. Simulations of data with typical turbulence profiles from Paranal were input to the profiler, showing that it is possible to identify reliably the input features for all the AOF modes.

  15. The VIMOS VLT Deep Survey: The K-band follow-up in the 0226-04 field

    CERN Document Server

    Temporin, S; Bolzonella, M; McCracken, H J; Scodeggio, M; Garilli, B; Bottini, D; Le Brun, V; Le Fèvre, O; MacCagni, D; Picat, J P; Scaramella, R; Tresse, L; Vettolani, G; Zanichelli, A; Adami, C; Arnouts, S; Bardelli, S; Cappi, A; Charlot, S; Ciliegi, P; Contini, T; Cucciati, O; Foucaud, S; Franzetti, P; Gavignaud, I; Guzzo, L; Ilbert, O; Marano, B; Marinoni, C; Mazure, A; Meneux, B; Merighi, R; Paltani, S; Pellò, R; Pollo, A; Pozzetti, L; Radovich, M; Vergani, D; Zamorani, G; Zucca, E; Bondi, M; Bongiorno, A; Brinchmann, J; De la Torre, S; Lamareille, F; Mellier, Y; Walcher, C J

    2008-01-01

    AIMS. We present a new Ks-band survey that represents a significant extension to the previous wide-field Ks-band imaging survey within the 0226-04 field of the VIMOS-VLT deep survey (VVDS). The new data add ~ 458 arcmin^2 to the previous imaging program, thus allowing us to cover a total contiguous area of ~ 600 arcmin^2 within this field. METHODS. Sources are identified both directly on the final K-band mosaic image and on the corresponding, deep chi^2-g'r'i' image from the CFHT Legacy Survey in order to reduce contamination while ensuring us the compilation of a truly K-selected catalogue down to the completeness limit of the Ks-band. The newly determined Ks-band magnitudes are used in combination with the ancillary multiwavelength data for the determination of accurate photometric redshifts. RESULTS. The final catalogue totals ~ 52000 sources, out of which ~ 4400 have a spectroscopic redshift from the VVDS first epoch survey. The catalogue is 90% complete down to K_Vega = 20.5 mag. We present K_s-band gala...

  16. VizieR Online Data Catalog: CLASH-VLT: the FF cluster MACS J0416.1-2403 (Balestra+, 2016)

    Science.gov (United States)

    Balestra, I.; Mercurio, A.; Sartoris, B.; Girardi, M.; Grillo, C.; Nonino, M.; Rosati, P.; Biviano, A.; Ettori, S.; Forman, W.; Jones, C.; Koekemoer, A.; Medezinski, E.; Merten, J.; Ogrean, G. A.; Tozzi, P.; Umetsu, K.; Vanzella, E.; van Weeren, R. J.; Zitrin, A.; Annunziatella, M.; Caminha, G. B.; Broadhurst, T.; Coe, D.; Donahue, M.; Fritz, A.; Frye, B.; Kelson, D.; Lombardi, M.; Maier, C.; Meneghetti, M.; Monna, A.; Postman, M.; Scodeggio, M.; Seitz, S.; Ziegler, B.

    2016-07-01

    The cluster MACS J0416.1-2403 was observed between 2012 December and 2014 November as part of the ESO Large Programme 186.A-0798 "Dark Matter Mass Distributions of Hubble Treasury Clusters and the Foundations of ΛCDM Structure Formation Models" (P.I.: Piero Rosati) using VIMOS at the ESO VLT. A total of 21 masks were observed (15 LR-Blue (low-resolution) masks and 6 MR (medium-resolution) masks). The LR-Blue masks cover the spectral range 3700-6700Å with a resolution of R=180, while the MR masks cover the range 4800-10000Å with a resolution of R=580. The massive cluster has been observed with the Hubble Space Telescope (HST) as part of the Multi-Cycle Treasury program Cluster Lensing And Supernova survey with Hubble (CLASH; P.I.: M. Postman; Postman et al. 2012, J/ApJS/199/25). The HST survey is nicely complemented by Subaru wide-field imaging. (3 data files).

  17. Investigating the nature of the z~2.8 submillimeter selected galaxy SMM J02399-0136 with VLT spectropolarimetry

    CERN Document Server

    Vernet, J; Vernet, Joel; Cimatti, Andrea

    2001-01-01

    We present deep optical spectropolarimety of SMM J02399-0136 (z=2.8) done with the VLT Antu 8.2 m telescope equipped with FORS1. Moderate continuum and emission line polarization are measured (P~5%). We do not detect broad lines in scattered flux as would be expected for a type-2 object but rather a polarization behaviour similar to BAL quasars. This classification is confirmed by the detection of both high and low ionization broad absorption troughs and a very red continuum. We argue that this object shares several properties with local ULIGs such as Mrk 231 and other ultraluminous infrared Lo-BAL quasars. However, the fact that the ultraviolet spectrum is dominated by non-stellar radiation does not prove that the dust that is thermally radiating in the far infrared is predominantly heated by the AGN. Since the energy that we get in the far-infrared is precisely that which is removed from the ultraviolet spectrum, this could mean that the starburst is more dust-enshrouded than the AGN due to a peculiar dust ...

  18. Correction of Field Rotator-Induced Flat-Field Systematics - A Case Study Using Archived VLT-FORS Data

    CERN Document Server

    Moehler, S; Moller, P; Patat, F; Rupprecht, G; O'Brien, K; 10.1086/649963

    2010-01-01

    ESO's two FOcal Reducer and low dispersion Spectrographs (FORS) are the primary optical imaging instruments for the VLT. They are not direct-imaging instruments, as there are several optical elements in the light path. In particular, both instruments are attached to a field rotator. Obtaining truly photometric data with such instruments present a significant challenge. In this paper, we investigate in detail twilight flats taken with the FORS instruments. We find that a large fraction of the structure seen in these flatfields rotates with the field rotator. We discuss in detail the methods we use to determine the cause of this effect. The effect was tracked down to be caused by the Linear Atmospheric Dispersion Corrector (LADC). The results are thus of special interest for designers of instruments with LADCs and developers of calibration plans and pipelines for such instruments. The methods described here to find and correct it, however, are of interest also for other instruments using a field rotator. If not...

  19. The close circumstellar environment of Betelgeuse - Adaptive optics spectro-imaging in the near-IR with VLT/NACO

    CERN Document Server

    Kervella, Pierre; Ridgway, Stephen T; Perrin, Guy; Lacour, Sylvestre; Cami, Jan; Haubois, Xavier

    2009-01-01

    Context: Betelgeuse is one the largest stars in the sky in terms of angular diameter. Structures on the stellar photosphere have been detected in the visible and near-infrared as well as a compact molecular environment called the MOLsphere. Mid-infrared observations have revealed the nature of some of the molecules in the MOLsphere, some being the precursor of dust. Aims: Betelgeuse is an excellent candidate to understand the process of mass loss in red supergiants. Using diffraction-limited adaptive optics (AO) in the near-infrared, we probe the photosphere and close environment of Betelgeuse to study the wavelength dependence of its extension, and to search for asymmetries. Methods: We obtained AO images with the VLT/NACO instrument, taking advantage of the "cube" mode of the CONICA camera to record separately a large number of short-exposure frames. This allowed us to adopt a "lucky imaging" approach for the data reduction, and obtain diffraction-limited images over the spectral range 1.04-2.17 $\\mu$m in 1...

  20. Chemical abundances in the protoplanetary disk LV2 (Orion) - II: High dispersion VLT observations and microjet properties

    CERN Document Server

    Tsamis, Y G

    2011-01-01

    Integral field spectroscopy of the LV2 proplyd is presented taken with the VLT/FLAMES Argus array at an angular resolution of 0.31x0.31 arcsec^2 and velocity resolutions down to 2 km/s per pixel. Following subtraction of the local M42 emission, the spectrum of LV2 is isolated from the surrounding nebula. We measured the heliocentric velocities and widths of a number of lines detected in the intrinsic spectrum of the proplyd, as well as in the adjacent Orion nebula within a 6.6 x 4.2 arcsec^2 FoV. It is found that far-UV to optical collisional lines with critical densities, Ncrit, ranging from 10^3 to 10^9 /cm^3 suffer collisional de-excitation near the rest velocity of the proplyd correlating tightly with their critical densities. Lines of low Ncrit are suppressed the most. The bipolar jet arising from LV2 is spectrally and spatially well-detected in several emission lines. We compute the [O III] electron temperature profile across LV2 in velocity space and measure steep temperature variations associated with...

  1. Luminosity functions in the CLASH-VLT cluster MACS J1206.2-0847: the importance of tidal interactions

    CERN Document Server

    Mercurio, A; Biviano, A; Nonino, M; Rosati, P; Balestra, I; Brescia, M; Girardi, M; Gobat, R; Grillo, C; Lombardi, M; Sartoris, B

    2015-01-01

    We present the optical luminosity functions (LFs) of galaxies for the CLASH-VLT cluster MACS J1206.2-0847 at z=0.439, based on HST and SUBARU data, including ~600 spectroscopically confirmed member galaxies. The LFs on the wide SUBARU FoV are well described by a single Schechter function down to M~M*+3, whereas this fit is poor for HST data, due to a faint-end upturn visible down M~M*+7, suggesting a bimodal behaviour. We also investigate the effect of local environment by deriving the LFs in four different regions, according to the distance from the centre, finding an increase in the faint-end slope going from the core to the outer rings. Our results confirm and extend our previous findings on the analysis of mass functions, which showed that the galaxies with stellar mass below 10^10.5, M_sun have been significantly affected by tidal interaction effects, thus contributing to the intra cluster light.

  2. VLT/NACO Polarimetric Differential Imaging of HD100546 - Disk Structure and Dust Grain Properties between 10-140 AU

    CERN Document Server

    Quanz, Sascha P; Geissler, Kerstin; Meyer, Michael R; Henning, Thomas; Brandner, Wolfgang; Wolf, Sebastian

    2011-01-01

    We present polarimetric differential imaging (PDI) data of the circumstellar disk around the Herbig Ae/Be star HD100546 obtained with VLT/NACO. We resolve the disk in polarized light in the H and Ks filter between ~0.1-1.4" (i.e., ~10-140 AU). The innermost disk regions are directly imaged for the first time and the mean apparent disk inclination and position angle are derived. The surface brightness along the disk major axis drops off roughly with S(r) ~ r^-3 but has a maximum around 0.15" suggesting a marginal detection of the main disk inner rim at ~15 AU. We find a significant brightness asymmetry along the disk minor axis in both filters with the far side of the disk appearing brighter than the near side. This enhanced backward scattering and a low total polarization degree of the scattered disk flux of 14%(+19%/-8%) suggests that the dust grains on the disk surface are larger than typical ISM grains. Empirical scattering functions reveal the backward scattering peak at the largest scattering angles and ...

  3. Resolving the inner regions of the HD97048 circumstellar disk with VLT/NACO polarimetric differential imaging

    CERN Document Server

    Quanz, Sascha P; Apai, Daniel; Wolf, Sebastian; Henning, Thomas

    2011-01-01

    Circumstellar disks are the cradles of planetary systems and their physical and chemical properties directly influence the planet formation process. As most planets supposedly form in the inner disk regions, i.e., within a few tens of AU, it is crucial to study circumstellar disk on these scales to constrain the conditions for planet formation. Our aims are to characterize the inner regions of the circumstellar disk around the young Herbig Ae/Be star HD97048 in polarized light. We use VLT/NACO to observe HD97048 in polarimetric differential imaging (PDI) mode in the H and Ks band. We spatially resolve the disk around HD97048 in polarized flux in both filters on scales between ~0.1"-1.0" corresponding to the inner ~16-160 AU. Fitting isophots to the flux calibrated H-band image between 13 - 14 mag/arcsec^2 and 14 - 15 mag/arcsec^2 we derive a apparent disk inclination angle of 34+-5 deg and 47+-2 deg, respectively. The disk position angle in both brightness regimes is almost identical and roughly 80 deg. Along...

  4. Deep VLT search for globular clusters in NGC 5128 color-magnitude diagrams and globular cluster luminosity function

    CERN Document Server

    Rejkuba, M

    2001-01-01

    At the distance of NGC 5128 (3.6 \\pm 0.2 Mpc) it is possible to resolve globular clusters with high resolution imaging from the ground, thus allowing the globular cluster candidate selection primarily through their morphological properties. I report the discovery of 71 globular clusters in NGC 5128 on VLT UT1+FORS1 images, including the faintest members (Mv ~ -5) known to date in this galaxy as well as 5 previously known clusters. U- and V-band photometry has been measured for all the candidates and the luminosity function, spanning -10.1

  5. Ground-based astrometry with wide field imagers. V. Application to near-infrared detectors: HAWK-I@VLT/ESO

    CERN Document Server

    Libralato, M; Bedin, L R; Piotto, G; Platais, I; Kissler-Patig, M; Milone, A P; .,

    2014-01-01

    High-precision astrometry requires accurate point-spread function modeling and accurate geometric-distortion corrections. This paper demonstrates that it is possible to achieve both requirements with data collected at the high acuity wide-field K-band imager (HAWK-I), a wide-field imager installed at the Nasmyth focus of UT4/VLT ESO 8m telescope. Our final astrometric precision reaches ~3 mas per coordinate for a well-exposed star in a single image with a systematic error less than 0.1 mas. We constructed calibrated astro-photometric catalogs and atlases of seven fields: the Baade's Window, NGC 6656, NGC 6121, NGC 6822, NGC 6388, NGC 104, and the James Webb Space Telescope calibration field in the Large Magellanic Cloud. We make these catalogs and images electronically available to the community. Furthermore, as a demonstration of the efficacy of our approach, we combined archival material taken with the optical wide-field imager at the MPI/ESO 2.2m with HAWK-I observations. We showed that we are able to achi...

  6. Upholding the Unified Model for Active Galactic Nuclei: VLT/FORS2 Spectropolarimetry of Seyfert 2 galaxies

    CERN Document Server

    Almeida, Cristina Ramos; Ramos, A Asensio; Acosta-Pulido, J A; Hönig, S F; Alonso-Herrero, A; Tadhunter, C N; González-Martín, O

    2016-01-01

    The origin of the unification model for Active Galactic Nuclei (AGN) was the detection of broad hydrogen recombination lines in the optical polarized spectrum of the Seyfert 2 galaxy (Sy2) NGC 1068. Since then, a search for the hidden broad-line region (HBLR) of nearby Sy2s started, but polarized broad lines have only been detected in 30-40% of the nearby Sy2s observed to date. Here we present new VLT/FORS2 optical spectropolarimetry of a sample of 15 Sy2s, including Compton-thin and Compton-thick sources. The sample includes six galaxies without previously published spectropolarimetry, some of them normally treated as non-hidden BLR (NHBLR) objects in the literature, four classified as NHBLR, and five as HBLR based on previous data. We report >=4{\\sigma} detections of a HBLR in 11 of these galaxies (73% of the sample) and a tentative detection in NGC 5793, which is Compton-thick according to the analysis of X-ray data performed here. Our results confirm that at least some NHBLRs are misclassified, bringing p...

  7. Direct detection of scattered light gaps in the transitional disk around HD 97048 with VLT/SPHERE

    CERN Document Server

    Ginski, C; Pinilla, P; Dominik, C; Boccaletti, A; de Boer, J; Benisty, M; Biller, B; Feldt, M; Garufi, A; Keller, C U; Kenworthy, M; Maire, A L; Ménard, F; Mesa, D; Milli, J; Min, M; Pinte, C; Quanz, S P; van Boekel, R; Bonnefoy, M; Chauvin, G; Desidera, S; Gratton, R; Girard, J H V; Keppler, M; Kopytova, T; Lagrange, A -M; Langlois, M; Rouan, D; Vigan, A

    2016-01-01

    We studied the well known circumstellar disk around the Herbig Ae/Be star HD 97048 with high angular resolution to reveal undetected structures in the disk, which may be indicative of disk evolutionary processes such as planet formation. We used the IRDIS near-IR subsystem of the extreme adaptive optics imager SPHERE at the ESO/VLT to study the scattered light from the circumstellar disk via high resolution polarimetry and angular differential imaging. We imaged the disk in unprecedented detail and revealed four ring-like brightness enhancements and corresponding gaps in the scattered light from the disk surface with radii between 39 au and 341 au. We derived the inclination and position angle as well as the height of the scattering surface of the disk from our observational data. We found that the surface height profile can be described by a single power law up to a separation ~270 au. Using the surface height profile we measured the scattering phase function of the disk and found that it is well consistent ...

  8. Deep VLT/HAWKI and Keck/MOSFIRE K-band imaging of the Hubble Frontier Fields

    Science.gov (United States)

    Brammer, Gabriel; Marchesini, Danilo

    2015-08-01

    We will present recently-obtained deep K-band imaging of the first four Frontier Fields, Abell 2744 and MACS 0416 with the VLT/HAWK-I instrument and MACS-0717 and MACS-1149 with Keck/MOSFIRE. The final HAWK-I mosaics reach a depth of K~26 AB (5-sigma) with superb ground-based image quality ~0.4" FWHM across the field; shorter integrations with MOSFIRE reach K~25 AB and with FWHM~0.5". The 7'x7' HAWKI field of view provides ideal simultaneous coverage of both the HST cluster and parallel fields (with additional area also covered by Subaru optical and IRAC imaging), and the K band at 2.2 µm crucially fills the gap between the deep space-based imaging bandpasses observed with HST and Spitzer. The addition of the 2.2 µm imaging and photometry greatly improves the constraints on both the photometric redshifts and the stellar-population properties of galaxies extending well below the characteristic stellar mass across most of the age of the universe, down to, and including, the redshifts of the targeted galaxy clusters. The reduced, aligned mosaics of all the K-band fields are made freely available to the Frontier Fields community; identical deep HAWK-I observations of the final two Frontier Fields (Abell 370 and Abell S1063) have been awarded and will be obtained in the upcoming ESO observing periods.

  9. The H-alpha luminosity function at redshift 2.2: A new determination using VLT/HAWK-I

    CERN Document Server

    Hayes, Matthew; Ostlin, Goran

    2009-01-01

    We aim to place new, strengthened constraints on the luminosity function (LF) of H-alpha emitting galaxies at redshift z=2.2, and to further constrain the instantaneous star-formation rate density of the universe (rho*). We have used the new HAWK-I instrument at ESO-VLT to obtain extremely deep narrow-band (line; NB2090) and broad-band (continuum; Ks) imaging observations. The target field is in the GOODS-South, providing us with a rich multi-wavelength auxiliary data set, which we utilise for redshift confirmation and to estimate dust content. We use this new data to measure the faint-end slope (alpha) of LF(H-alpha) with unprecedented precision. The data are well fit by a Schechter function and also a single power-law, yielding alpha=(-1.72 +/- 0.20) and (-1.77 +/- 0.21), respectively. Thus we are able to confirm the steepening of alpha from low- to high-z predicted by a number of authors and observed at other wavelengths. We combine our LF data-points with those from a much shallower but wider survey at z=...

  10. CLASH-VLT: Environment-driven evolution of galaxies in the z=0.209 cluster Abell 209

    CERN Document Server

    Annunziatella, M; Biviano, A; Girardi, M; Nonino, M; Balestra, I; Rosati, P; Caminha, G Bartosch; Brescia, M; Gobat, R; Grillo, C; Lombardi, M; Sartoris, B; De Lucia, G; Demarco, R; Frye, B; Fritz, A; Moustakas, J; Scodeggio, M; Kuchner, U; Maier, C; Ziegler, B

    2016-01-01

    The analysis of galaxy properties and the relations among them and the environment, can be used to investigate the physical processes driving galaxy evolution. We study the cluster A209 by using the CLASH-VLT spectroscopic data combined with Subaru photometry, yielding to 1916 cluster members down to a stellar mass of 10^{8.6} Msun. We determine: i) the stellar mass function of star-forming and passive galaxies; ii) the intra-cluster light and its properties; iii) the orbits of low- and high-mass passive galaxies; and iv) the mass-size relation of ETGs. The stellar mass function of the star-forming galaxies does not depend on the environment, while the slope found for passive galaxies becomes flatter in the densest region. The color distribution of the intra-cluster light is consistent with the color of passive members. The analysis of the dynamical orbits shows that low-mass passive galaxies have tangential orbits, avoiding small pericenters around the BCG. The mass-size relation of low-mass passive ETGs is ...

  11. The Four-Laser Guide Star Facility (4LGSF) for the ESO VLT Adaptive Optics Facility (AOF)

    Science.gov (United States)

    Hackenberg, W.; Bonaccini Calia, D.; Lewis, S.; Holzlohner, R.; Buzzoni, B.; Comin, M.; Dupuy, C.; Guidolin, I. M.; Kern, L.; Quattri, M.; Quentin, J.; Ridings, R.; Argomedo, J.; Arsenault, R.; Conzelmann, R.; Delabre, B.; Donaldson, R.; Downing, M.; Duchateau, M.; Hubin, N.; Igl, G.; Jochum, L.; Jolley, P.; Jost, A.; Kiekebusch, M.; Kolb, J.; Kuntschner, H.; Lizon, J.-L.; Le Louarn, M.; Madec, P.-Y.; Manescau, A.; Paufique, J.; Pirard, J.-F.; Reyes, J.; Silber, A.; Soenke, C.; Stroebele, S.; Stuik, R.; Tordo, S.; Vernet, E.; Collazos, R. Guzman

    2011-09-01

    The 4LGSF is to be installed as a subsystem of the ESO Adaptive Optics Facility (AOF) on Unit Telescope 4 (UT4) of the VLT, to provide the AO systems GALACSI/MUSE and GRAAL/HAWK-I with four sodium laser guide stars. The 4LGSF will deploy four modular LGS Units at the UT4 Centrepiece. Two key aspects of the 4LGSF design are: (i) new industrial laser source (fibre lasers) with reduced volume, reduced need of maintenance, higher reliability, simpler operation and optimised spectral format for highly efficient sodium excitation, (ii) modular structure of the four LGS Units, composed of the laser and laser launch telescope, capable to operate independently of the others. The final design of the 4LGSF is now complete and the project has entered the manufacturing, assembly, integration and test phase. Furthermore, modular LGS units containing the laser emitter integrated on the launch telescope have already been demonstrated at ESO in the past years, and results will be presented. We believe that having the laser sources as an integral part of a modular unit together with the launching system offers many advantages at the system level, including the avoidance of beam relays, retaining the flexibility to use as many LGS as required independently, and the possibility of building redundancy into the system. We believe that many of these 4LGSF concepts can serve for ELT multi-LGS-assisted adaptive telescope designs and provide a valuable experience in advance of the E-ELT.

  12. Deep VLT spectroscopy of high redshift radio galaxy MRC 2104-242 Evidence for a metallicity gradient

    CERN Document Server

    Overzier, R; Kurk, J D; De Breuck, C

    2001-01-01

    In this contribution we will present deep VLT spectroscopy observations of the giant emission line halo around the z=2.49 radio galaxy MRC 2104-242. The morphology of the halo is dominated by two spatially resolved regions. Lya is extended by >12" along the radio axis, C IV and He II are extended by ~8". The overall spectrum is typical for that of high redshift radio galaxies. Interestingly, N V is present in the spectrum of the region associated with the center of the galaxy hosting the radio source, the northern region, while absent in the southern region. Using a simple photoionization model, the difference in N V can be explained due to a metallicity gradient within the halo. This is consistent with a scenario in which the halo is formed by a massive cooling flow or originates from the debris of the merging of two or more galaxies. However, also other mechanisms such as jet-cloud interactions or starburst-winds could be important.

  13. The infrared K-band identification of the DSO/G2 source from VLT and Keck data

    CERN Document Server

    Eckart, Andreas; Britzen, S; Zamaninasab, M; Muzic, K; Sabha, N; Shahzamanian, B; Yazici, S; Moser, L; Garcia-Mari, M; Valencia-S., M; Borkar, A; Bursa, M; Karssen, G; Karas, V; Zajacek, M; Bronfman, L; Finger, R; Jalali, B; Vitale, M; Rauch, C; Kunneriath, D; Moultaka, J; Straubmeier, C; Rashed, Y E; Markakis, K; Zensus, A

    2013-01-01

    A fast moving infrared excess source (G2) which is widely interpreted as a core-less gas and dust cloud approaches Sagittarius A* (SgrA*) on a presumably elliptical orbit. VLT K_s-band and Keck K'-band data result in clear continuum identifications and proper motions of this about 19m Dusty S-cluster Object (DSO). In 2002-2007 it is confused with the star S63, but free of confusion again since 2007. Its near-infrared (NIR) colors and a comparison to other sources in the field speak in favor of the DSO being an IR excess star with photospheric continuum emission at 2 microns than a core-less gas and dust cloud. We also find very compact L'-band emission ($<$0.1'') contrasted by the reported extended (0.03'' up to about 0.2'' for the tail) Brgamma emission. The presence of a star will change the expected accretion phenomena, since a stellar Roche lobe may retain a fraction of the material during and after the peri-bothron passage.

  14. The VLT-FLAMES Tarantula Survey XVIII. Classifications and radial velocities of the B-type stars

    CERN Document Server

    Evans, C J; Dufton, P L; Howarth, I D; Walborn, N R; Markova, N; Clark, J S; de Mink, S E; de Koter, A; Dunstall, P R; Hénault-Brunet, V; Apellániz, J Maíz; McEvoy, C M; Sana, H; Simón-Díaz, S; Taylor, W D; Vink, J S

    2015-01-01

    We present spectral classifications for 438 B-type stars observed as part of the VLT-FLAMES Tarantula Survey (VFTS) in the 30 Doradus region of the Large Magellanic Cloud. Radial velocities are provided for 307 apparently single stars, and for 99 targets with radial-velocity variations which are consistent with them being spectroscopic binaries. We investigate the spatial distribution of the radial velocities across the 30 Dor region, and use the results to identify candidate runaway stars. Excluding potential runaways and members of two older clusters in the survey region (SL 639 and Hodge 301), we determine a systemic velocity for 30 Dor of 271.6 +/- 12.2 km/s from 273 presumed single stars. Employing a 3-sigma criterion we identify nine candidate runaway stars (2.9% of the single stars with radial-velocity estimates). The projected rotational velocities of the candidate runaways appear to be significantly different to those of the full B-type sample, with a strong preference for either large (>345 km/s) or...

  15. The VLT-FLAMES Tarantula Survey IV: Candidates for isolated high-mass star formation in 30 Doradus

    CERN Document Server

    Bressert, E; Evans, C J; Sana, H; Hénault-Brunet, V; Goodwin, S P; Parker, R J; Gieles, M; Bestenlehner, J M; Vink, J S; Taylor, W D; Crowther, P A; Longmore, S N; Gräfener, G; Apellániz, J Maíz; de Koter, A; Cantiello, M; Kruijssen, J M D

    2012-01-01

    Whether massive stars can occasionally form in relative isolation or if they require a large cluster of lower-mass stars around them is a key test in the differentiation of star formation theories as well as how the initial mass function of stars is sampled. Previous attempts to find O-type stars that formed in isolation were hindered by the possibility that such stars are merely runaways from clusters, i.e., their current isolation does not reflect their birth conditions. We introduce a new method to find O-type stars that are not affected by such a degeneracy. Using the VLT-FLAMES Tarantula Survey and additional high resolution imaging we have identified stars that satisfy the following constraints: 1) they are O-type stars that are not detected to be part of a binary system based on RV time series analysis; 2) they are designated spectral type O7 or earlier ; 3) their velocities are within 1\\sigma of the mean of OB-type stars in the 30 Doradus region, i.e. they are not runaways along our line-of-sight; 4) ...

  16. The VLT-FLAMES Tarantula Survey. VII. A low velocity dispersion for the young massive cluster R136

    CERN Document Server

    Hénault-Brunet, V; Sana, H; Gieles, M; Bastian, N; Apellániz, J Maíz; Markova, N; Taylor, W D; Bressert, E; Crowther, P A; van Loon, J Th

    2012-01-01

    Detailed studies of resolved young massive star clusters are necessary to determine their dynamical state and evaluate the importance of gas expulsion and early cluster evolution. In an effort to gain insight into the dynamical state of the young massive cluster R136 and obtain the first measurement of its velocity dispersion, we analyse multi-epoch spectroscopic data of the inner regions of 30 Doradus in the Large Magellanic Cloud (LMC) obtained as part of the VLT-FLAMES Tarantula Survey. Following a quantitative assessment of the variability, we use the radial velocities of non-variable sources to place an upper limit of 6 km/s on the line-of-sight velocity dispersion of stars within a projected distance of 5 pc from the centre of the cluster. After accounting for the contributions of undetected binaries and measurement errors through Monte Carlo simulations, we conclude that the true velocity dispersion is likely between 4 and 5 km/s given a range of standard assumptions about the binary distribution. This...

  17. The VLT-FLAMES Tarantula Survey XXV. Surface nitrogen abundances of O-type giants and supergiants

    CERN Document Server

    Grin, N J; de Koter, A; Sana, H; Puls, J; Brott, I; Crowther, P A; Dufton, P L; Evans, C J; Graefener, G; Herrero, A; Langer, N; Lennon, D J; van Loon, J Th; Markova, N; de Mink, S E; Najarro, F; Schneider, F R N; Taylor, W D; Tramper, F; Vink, J S; Walborn, W R

    2016-01-01

    Theoretically, rotation-induced chemical mixing in massive stars has far reaching evolutionary consequences, affecting the sequence of morphological phases, lifetimes, nucleosynthesis, and supernova characteristics. Using a sample of 72 presumably single O-type giants to supergiants observed in the context of the VLT-FLAMES Tarantula Survey (VFTS), we aim to investigate rotational mixing in evolved core-hydrogen burning stars initially more massive than $15\\,M_\\odot$ by analysing their surface nitrogen abundances. Using stellar and wind properties derived in a previous VFTS study, we constrained the nitrogen abundance by fitting the equivalent widths of relatively strong lines that are sensitive to changes in the abundance of this element. Given the quality of the data, we constrained the nitrogen abundance in 38 cases; for 34 stars only upper limits could be derived, which includes almost all stars rotating at $v_\\mathrm{e}\\sin i >200\\,\\mathrm{km s^{-1}}$. We analysed the nitrogen abundance as a function of ...

  18. VLT photometry in the Antlia Cluster: the giant ellipticals NGC 3258 and NGC 3268 and their globular cluster systems

    CERN Document Server

    Bassino, Lilia P; Dirsch, Boris

    2008-01-01

    We present a deep VLT photometry in the regions surrounding the two dominant galaxies of the Antlia cluster, the giant ellipticals NGC 3258 and NGC 3268. We construct the luminosity functions of their globular cluster systems (GCSs) and determine their distances through the turn-over magnitudes. These distances are in good agreement with those obtained by the SBF method. There is some, but not conclusive, evidence that the distance to NGC 3268 is larger by several Mpc. The GCSs colour distributions are bimodal but the brightest globular clusters (GCs) show a unimodal distribution with an intermediate colour peak. The radial distributions of both GCSs are well fitted by de Vaucouleurs laws up to 5 arcmin. Red GCs present a steeper radial density profile than the blue GCs, and follow closely the galaxies' brightness profiles. Total GC populations are estimated to be about 6000+/-150 GCs in NGC 3258 and 4750+/-150 GCs in NGC 3268. We discuss the possible existence of GCs in a field located between the two giant ...

  19. Deep vlt spectroscopy of high redshift radio galaxy MRC 2104{242: evidence for a metallicity gradient

    Directory of Open Access Journals (Sweden)

    R. Overzier

    2002-01-01

    Full Text Available En esta contribuci on vamos a presentar observaciones espectrosc opicas profundas del VLT (siglas en ingl es: Very Large Telescope del halo gigante de l neas de emisi on alrededor de la radiogalaxia MRC 2104{242 a z = 2:49. La morfolog a del halo viene determinado por dos regiones espaciales resueltas. Ly se extiende por > 1200 a lo largo del radioeje, C IV 1549 y He II 1640 se extienden por 800. El espectro total es t pico para radiogalaxias de alto corrimiento al rojo. Es interesante notar que N V 1240 est a presente en el espectro de la regi on asociada con el centro de la galaxia que contiene la radiofuente, la regi on del norte, mientras que est a ausente en la regi on del sur. Usando un modelo de fotoionizaci on simple, la diferencia en la emisi on N V 1240 se puede explicar por un gradiente de metalicidad en el halo. Esto es consistente con un escenario en el cual el halo se form o por un "cooling ow" masivo o tiene su origen en los residuos de la fusi on de dos o m as galaxias. Sin embargo, tambi en podr an ser importantes otros mecanismos como son las interacciones entre jets y nubes y los vientos debido a un \\starburst".

  20. VLT/X-shooter observations of the low-metallicity blue compact dwarf galaxy PHL 293B including a luminous blue variable star

    Science.gov (United States)

    Izotov, Y. I.; Guseva, N. G.; Fricke, K. J.; Henkel, C.

    2011-09-01

    Context. We present VLT/X-shooter spectroscopic observations in the wavelength range λλ3000-23 000 Å of the extremely metal-deficient blue compact dwarf (BCD) galaxy PHL 293B containing a luminous blue variable (LBV) star and compare them with previous data. Aims: This BCD is one of the two lowest-metallicity galaxies where LBV stars were detected, allowing us to study the LBV phenomenon in the extremely low metallicity regime. Methods: We determine abundances of nitrogen, oxygen, neon, sulfur, argon, and iron by analyzing the fluxes of narrow components of the emission lines using empirical methods and study the properties of the LBV from the fluxes and widths of broad emission lines. Results: We derive an interstellar oxygen abundance of 12+log O/H = 7.71 ± 0.02, which is in agreement with previous determinations. The observed fluxes of narrow Balmer, Paschen and Brackett hydrogen lines correspond to the theoretical recombination values after correction for extinction with a single value C(Hβ) = 0.225. This implies that the star-forming region observed in the optical range is the only source of ionisation and there is no additional source of ionisation that is seen in the NIR range but is hidden in the optical range. We detect three v = 1-0 vibrational lines of molecular hydrogen. Their flux ratios and non-detection of v = 2-1 and 3-1 emission lines suggest that collisional excitation is the main source producing H2 lines. For the LBV star in PHL 293B we find broad emission with P Cygni profiles in several Balmer hydrogen emission lines and for the first time in several Paschen hydrogen lines and in several He i emission lines, implying temporal evolution of the LBV on a time scale of 8 years. The Hα luminosity of the LBV star is by one order of magnitude higher than the one obtained for the LBV star in NGC 2363 ≡ Mrk 71 which has a slightly higher metallicity 12+logO/H = 7.87. The terminal velocity of the stellar wind in the low-metallicity LBV of PHL293

  1. Pileup correction of microdosimetric spectra

    CERN Document Server

    Langen, K M; Lennox, A J; Kroc, T K; De Luca, P M

    2002-01-01

    Microdosimetric spectra were measured at the Fermilab neutron therapy facility using low pressure proportional counters operated in pulse mode. The neutron beam has a very low duty cycle (<0.1%) and consequently a high instantaneous dose rate which causes distortions of the microdosimetric spectra due to pulse pileup. The determination of undistorted spectra at this facility necessitated (i) the modified operation of the proton accelerator to reduce the instantaneous dose rate and (ii) the establishment of a computational procedure to correct the measured spectra for remaining pileup distortions. In support of the latter effort, two different pileup simulation algorithms using analytical and Monte-Carlo-based approaches were developed. While the analytical algorithm allows a detailed analysis of pileup processes it only treats two-pulse and three-pulse pileup and its validity is hence restricted. A Monte-Carlo-based pileup algorithm was developed that inherently treats all degrees of pileup. This algorithm...

  2. Correlation Functions and Power Spectra

    DEFF Research Database (Denmark)

    Larsen, Jan

    2006-01-01

    The present lecture note is a supplement to the textbook Digital Signal Processing by J. Proakis and D.G. Manolakis used in the IMM/DTU course 02451 Digital Signal Processing and provides an extended discussion of correlation functions and power spectra. The definitions of correlation functions...... and spectra for discrete-time and continuous-time (analog) signals are pretty similar. Consequently, we confine the discussion mainly to real discrete-time signals. The Appendix contains detailed definitions and properties of correlation functions and spectra for analog as well as discrete-time signals....... It is possible to define correlation functions and associated spectra for aperiodic, periodic and random signals although the interpretation is different. Moreover, we will discuss correlation functions when mixing these basic signal types. In addition, the note include several examples for the purpose...

  3. Absorption Spectra of Astaxanthin Aggregates

    CERN Document Server

    Olsina, Jan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas

    2012-01-01

    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption maximum of monomeric astaxanthin (470-495 nm depending on solvent) are caused by excitonic interaction between aggregated molecules. We applied molecular dynamics simulations to elucidate structure of astaxanthin dimer in water, and the resulting structure was used as a basis for calculations of absorption spectra. Absorption spectra of astaxanthin aggregates in hydrated dimethylsulfoxide were calculated using molecular exciton model with the resonance interaction energy between astaxanthin monomers constrained by semi-e...

  4. Infrared spectra of mineral species

    CERN Document Server

    Chukanov, Nikita V

    2014-01-01

    This book details more than 3,000 IR spectra of more than 2,000 mineral species collected during last 30 years. It features full descriptions and analytical data of each sample for which IR spectrum was obtained.

  5. Importância da velocidade do movimento celular na câmara anterior, na avaliação clínica das uveítes Importance of the speed of the cellular movement in the anterior chamber in the clinical evaluation of uveitis

    Directory of Open Access Journals (Sweden)

    Fernando Antônio L. Mendes Furtado

    2000-08-01

    Full Text Available Objetivo: Acrescentar ao oftalmologista mais um dado para avaliação clínica das uveítes, que acometem o segmento anterior; seja contribuindo para revelar a intensidade do processo inflamatório, seja ajudando a nortear a conduta terapêutica. Métodos: Estudamos 46 pacientes portadores de uveíte e com reação celular na câmara anterior. Observamos a velocidade do deslocamento das células no humor aquoso e a relacionamos com a intensidade do processo inflamatório, comparando com a sintomatologia e principais sinais clínicos. Resultados: Os resultados nos mostram que existe uma correlação direta entre a velocidade das células na câmara anterior e o grau de inflamação. Quanto mais grave a inflamação, menor é o deslocamento das células. E podemos aplicar esse fato na abordagem clínica das uveítes. Em algumas situações é mais fácil perceber alterações na velocidade que na quantidade de células ou flare. Conclusões: Nosso estudo apresenta um elemento novo na semiologia das uveítes, já que não encontramos referências na literatura médica. Familiarizando-se com a velocidade dos movimentos celulares na câmara anterior, podemos dispor de uma valioso recurso que nos ajude no exame do paciente com uveíte. Há casos em que a mudança na velocidade é o único elemento a nos indicar uma piora ou melhora do quadro clínico.Purpose: To add for the ophthalmologist an element for clinical evaluation of uveitis, affecting the anterior segment; contributing both to reveal the intensity of the inflammatory process and helping to guide the therapeutic management conduct. Methods: We studied 46 uveitis patients with cellular reaction in the anterior chamber. We observed the speed of the displacement of the cells in the aqueous humor and related it to the intensity of the inflammatory process, in comparison with the symptomatology and main clinical signs. Results: The results showed that there is an inverse correlation between the

  6. Lyman-α emitters in the context of hierarchical galaxy formation: predictions for VLT/MUSE surveys

    Science.gov (United States)

    Garel, T.; Guiderdoni, B.; Blaizot, J.

    2016-02-01

    The VLT/Multi Unit Spectrograph Explorer (MUSE) integral-field spectrograph can detect Lyα emitters (LAE) in the redshift range 2.8 ≲ z ≲ 6.7 in a homogeneous way. Ongoing MUSE surveys will notably probe faint Lyα sources that are usually missed by current narrow-band surveys. We provide quantitative predictions for a typical wedding-cake observing strategy with MUSE based on mock catalogues generated with a semi-analytic model of galaxy formation coupled to numerical Lyα radiation transfer models in gas outflows. We expect ≈1500 bright LAEs (FLyα ≳ 10-17 erg s-1 cm-2) in a typical shallow field (SF) survey carried over ≈100 arcmin2 , and ≈2000 sources as faint as 10-18 erg s-1 cm-2 in a medium-deep field (MDF) survey over 10 arcmin2 . In a typical deep field (DF) survey of 1 arcmin2 , we predict that ≈500 extremely faint LAEs (FLyα ≳ 4 × 10-19 erg s-1 cm-2) will be found. Our results suggest that faint Lyα sources contribute significantly to the cosmic Lyα luminosity and SFR budget. While the host haloes of bright LAEs at z ≈ 3 and 6 have descendants with median masses of 2 × 1012 and 5 × 1013 M⊙, respectively, the faintest sources detectable by MUSE at these redshifts are predicted to reside in haloes which evolve into typical sub-L* and L* galaxy haloes at z = 0. We expect typical DF and MDF surveys to uncover the building blocks of Milky Way-like objects, even probing the bulk of the stellar mass content of LAEs located in their progenitor haloes at z ≈ 3.

  7. CLASH-VLT: constraints on f(R) gravity models with galaxy clusters using lensing and kinematic analyses

    Science.gov (United States)

    Pizzuti, L.; Sartoris, B.; Amendola, L.; Borgani, S.; Biviano, A.; Umetsu, K.; Mercurio, A.; Rosati, P.; Balestra, I.; Caminha, G. B.; Girardi, M.; Grillo, C.; Nonino, M.

    2017-07-01

    We perform a maximum likelihood kinematic analysis of the two dynamically relaxed galaxy clusters MACS J1206.2-0847 at z=0.44 and RXC J2248.7-4431 at z=0.35 to determine the total mass profile in modified gravity models, using a modified version of the MAMPOSSt code of Mamon, Biviano and Bou&apose. Our work is based on the kinematic and lensing mass profiles derived using the data from the Cluster Lensing And Supernova survey with Hubble (hereafter CLASH) and the spectroscopic follow-up with the Very Large Telescope (hereafter CLASH-VLT). We assume a spherical Navarro-Frenk-White (NFW hereafter) profile in order to obtain a constraint on the fifth force interaction range λ for models in which the dependence of this parameter on the environment is negligible at the scale considered (i.e. λ=const) and fixing the fifth force strength to the value predicted in f(R) gravity. We then use information from lensing analysis to put a prior on the other NFW free parameters. In the case of MACSJ 1206 the joint kinematic+lensing analysis leads to an upper limit on the effective interaction range λdistribution. For RXJ 2248 instead a possible tension with the ΛCDM model appears when adding lensing information, with a lower limit λ>=0.14 mpc at Δχ2=2.71. This is consequence of the slight difference between the lensing and kinematic data, appearing in GR for this cluster, that could in principle be explained in terms of modifications of gravity. We discuss the impact of systematics and the limits of our analysis as well as future improvements of the results obtained. This work has interesting implications in view of upcoming and future large imaging and spectroscopic surveys, that will deliver lensing and kinematic mass reconstruction for a large number of galaxy clusters.

  8. Complex Spectra in Fusion Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Hellermann, M.G. von; Jaspers, R. [FOM-Institute for Plasma Physics Rijnhuizen, Nieuwegein (Netherlands); Bertschinger, G.; Biel, W.; Marchuk, O. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Plasmaphysik; Giroud, C.; Zastrow, K.D. [UKAEA Culham Laboratory Euratom Association, Abingdon (United Kingdom); Jupen, C. [Univ. of Lund (Sweden). Physics Dept.; O' Mullane, M.; Summers, H.P.; Whiteford, A. [Univ. of Strathclyde, Glasgow (United Kingdom). Applied Physics Dept.

    2005-12-15

    The need for quantitative evaluation of complex line emission spectra as observed in hot fusion plasmas initiated a challenging development of sophisticated interpretation tools based on integrating advanced atomic modelling with detailed treatment of the plasma environment. The successful merging of the two worlds has led to routine diagnostic procedures which have contributed enormously to the understanding of underlying plasma processes and also to a wide acceptance of spectroscopy as a reliable diagnostic method. In this paper three characteristic types of spectra of current and continuing interest are presented. The first is that of medium/heavy species with many ionisation stages revealed in survey VUV and XUV spectra. Such species occur as control gases, as wall materials, as ablated heavy species and possible as layered wall dopants for monitoring erosion. The spectra are complex with line-like and quasi-continuum regions and are amenable to advanced ?pattern recognition' methods. The second type is of few electron, highly ionised systems observed as line-of-sight integrated passive emission spectra in the soft X-ray region. They are analysed successfully in terms of plasma parameters through matching of observation with predicted synthetic spectra. Examples used here include highly resolved helium-like emission spectra of argon, iron and titanium observed on the tokamaks TEXTOR and Tore Supra. The third type, and the emphasis of this work, comprises spectra linked to active beam spectroscopy, that is, charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES). In this case, a complex spectrum is again composed of a (usually) dominating active spectrum and an underlying passive emission spectrum. Its analysis requires modelling of both active and passive features. Examples used here are from the CXRS diagnostic at JET and TEXTOR. They display characteristic features of the main light impurity ions (C{sup +6}, He{sup +2}, N

  9. Qualitative interpretation of galaxy spectra

    CERN Document Server

    Almeida, J Sanchez; Terlevich, E; Fernandes, R Cid; Morales-Luis, A B

    2012-01-01

    We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis, and for gaining physical insight when interpreting the outputs provided by automated tools. Though the recipe is of general application, it was developed for understanding the nature of the Automatic Spectroscopic K-means based (ASK) template spectra. They resulted from the classification of all the galaxy spectra in the Sloan Digital Sky Survey data release 7 (SDSS-DR7), thus being a comprehensive representation of the galaxy spectra in the local universe. Using the recipe, we give a description of the properties of the gas and the stars that characterize the ASK classes, from those corresponding to passively evolving galaxies, to HII galaxies undergoing a galaxy-wide starburst. The qualitative analysis is found to be in excellent agreement with quantitative analyses of the same spectra. A number of byprodu...

  10. The spectroscopic study of M8.5-M9.5 stars and brown dwarfs

    Directory of Open Access Journals (Sweden)

    Pavlenko Y.V.

    2013-04-01

    Full Text Available We present high-resolution spectra analysis of the three late-M dwarfs LP944-20, SIPS J2045-6332 and DENIS-P J0021.0-4244. The stellar spectra were observed with Very Large Telescope/Ultraviolet–Visual Echelle Spectrograph (VLT/UVES in optical and near-infrared regions. The effective temperatures Teff and log g was defined by comparing observed and theoretical energy distributions for the investigated objects. Synthetic spectra were calculated for PHOENIX atmosphere models – COND and DUSTY, as well as for Semi-empirical atmosphere model. We discuss the influence of the effects associated with dust in stellar atmosphere on the energy distribution in the stellar spectra.

  11. Accelerated Fitting of Stellar Spectra

    CERN Document Server

    Ting, Yuan-Sen; Rix, Hans-Walter

    2016-01-01

    Stellar spectra are often modeled and fit by interpolating within a rectilinear grid of synthetic spectra to derive the stars' labels: stellar parameters and elemental abundances. However, the number of synthetic spectra needed for a rectilinear grid grows exponentially with the label space dimensions, precluding the simultaneous and self-consistent fitting of more than a few elemental abundances. Shortcuts such as fitting subsets of parameters separately can introduce unknown systematics and do not produce correct error covariances in the derived labels. In this paper we present a new approach -- CHAT (Convex Hull Adaptive Tessellation) -- which includes several new ideas for inexpensively generating a sufficient stellar synthetic library, using linear algebra and the concept of an adaptive, data-driven grid. A convex hull approximates the region where the data lie in the label space. A variety of tests with mock datasets demonstrate that CHAT can reduce the number of required synthetic model calculations by...

  12. QUALITATIVE INTERPRETATION OF GALAXY SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Almeida, J.; Morales-Luis, A. B. [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain); Terlevich, R.; Terlevich, E. [Instituto Nacional de Astrofisica, Optica y Electronica, Tonantzintla, Puebla (Mexico); Cid Fernandes, R., E-mail: jos@iac.es, E-mail: abml@iac.es, E-mail: rjt@ast.cam.ac.uk, E-mail: eterlevi@inaoep.mx, E-mail: cid@astro.ufsc.br [Departamento de Fisica-CFM, Universidade Federal de Santa Catarina, P.O. Box 476, 88040-900 Florianopolis, SC (Brazil)

    2012-09-10

    We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis and for gaining physical insight when interpreting the outputs provided by automated tools. Though the recipe is for general application, it was developed for understanding the nature of the Automatic Spectroscopic K-means-based (ASK) template spectra. They resulted from the classification of all the galaxy spectra in the Sloan Digital Sky Survey data release 7, thus being a comprehensive representation of the galaxy spectra in the local universe. Using the recipe, we give a description of the properties of the gas and the stars that characterize the ASK classes, from those corresponding to passively evolving galaxies, to H II galaxies undergoing a galaxy-wide starburst. The qualitative analysis is found to be in excellent agreement with quantitative analyses of the same spectra. We compare the mean ages of the stellar populations with those inferred using the code STARLIGHT. We also examine the estimated gas-phase metallicity with the metallicities obtained using electron-temperature-based methods. A number of byproducts follow from the analysis. There is a tight correlation between the age of the stellar population and the metallicity of the gas, which is stronger than the correlations between galaxy mass and stellar age, and galaxy mass and gas metallicity. The galaxy spectra are known to follow a one-dimensional sequence, and we identify the luminosity-weighted mean stellar age as the affine parameter that describes the sequence. All ASK classes happen to have a significant fraction of old stars, although spectrum-wise they are outshined by the youngest populations. Old stars are metal-rich or metal-poor depending on whether they reside in passive galaxies or in star-forming galaxies.

  13. The 2008 outburst in the Young Stellar System Z CMa. III - Multi-epoch high-angular resolution images and spectra of the components in near-infrared

    CERN Document Server

    Bonnefoy, M; Dougados, C; Kospal, A; Benisty, M; Duchene, G; Bouvier, J; Garcia, P J V; Whelan, E; Antoniucci, S; Podio, L

    2016-01-01

    Z CMa is a complex pre-main sequence binary with a current separation of 100 mas, known to consist of an FU Orionis star (SE component) and an embedded Herbig Be star (NW component). Immediately when the late-2008 outburst of Z CMa was announced to the community, we initiated a high angular resolution imaging campaign with VLT/NaCo, Keck/NIRC2, VLT/SINFONI, and Keck/OSIRIS which aimed at characterizing the outburst of both components of the system in the near-infrared. We confirm that the NW star dominates the system flux in the 1.1-3.8 microns range and is responsible for the photometric outburst. We extract the first medium-resolution (R=2000-4000) near-infrared (1.1-2.4 microns) spectra of the individual components during and after the outburst. The SE component has a spectrum typical of FU Orionis objects. The NW component spectrum is characteristic of embedded outbursting protostars and EX Or objects. It displays numerous emission lines during the outburst whose intensity correlates with the system activ...

  14. Classical Trajectories and Quantum Spectra

    Science.gov (United States)

    Mielnik, Bogdan; Reyes, Marco A.

    1996-01-01

    A classical model of the Schrodinger's wave packet is considered. The problem of finding the energy levels corresponds to a classical manipulation game. It leads to an approximate but non-perturbative method of finding the eigenvalues, exploring the bifurcations of classical trajectories. The role of squeezing turns out decisive in the generation of the discrete spectra.

  15. Missing levels in correlated spectra

    CERN Document Server

    Bohigas, O

    2004-01-01

    Complete spectroscopy (measurements of a complete sequence of consecutive levels) is often considered as a prerequisite to extract fluctuation properties of spectra. It is shown how this goal can be achieved even if only a fraction of levels are observed. The case of levels behaving as eigenvalues of random matrices, of current interest in nuclear physics, is worked out in detail.

  16. Squeezed States and Helmholtz Spectra

    CERN Document Server

    Francisco Delgado, C; Reyes, M A; Mielnik, Bogdan; Reyes, Marco A

    1997-01-01

    The 'classical interpretation' of the wave function psi(x) reveals an interesting operational aspect of the Helmholtz spectra. It is shown that the traditional Sturm-Liouville problem contains the simplest key to predict the squeezing effect for charged particle states.

  17. Universal Behavior in Dirac Spectra

    CERN Document Server

    Verbaarschot, J J M

    1997-01-01

    In these lectures we review recent results on universal fluctuations of QCD Dirac spectra and applications of Random Matrix Theory (RMT) to QCD. We review general properties of Dirac spectra and discuss the relation between chiral symmetry breaking and correlations of Dirac eigenvalues. In particular, we will focus on the microscopic spectral density density, i.e. the spectral density near zero virtuality on the scale of a typical level spacing. The relation with Leutwyler-Smilga sum-rules will be discussed. The success of applications of RMT to spectra of 'complex' systems leads us to the introduction of a chiral Random Matrix Theory (chRMT) with the global symmetries of the QCD partition function. Our central conjecture is that it decribes correlations of QCD Dirac spectra. We will review recent universality proofs supporting this conjecture. Lattice QCD results for the microscopic spectral density and for correlations in the bulk of the spectrum are shown to be in perfect agreement with chRMT. We close wit...

  18. Gallery of Planetary Nebula Spectra

    CERN Document Server

    Kwitter, K B; Kwitter, Karen B.; Henry, Richard B.C.

    2006-01-01

    We present the Gallery of Planetary Nebula Spectra now available at http://oitwilliams.edu/nebulae. The website offers high-quality, moderate resolution (~7-10 A FWHM) spectra of 128 Galactic planetary nebulae from 3600-9600 A, obtained by Kwitter, Henry, and colleagues with the Goldcam spectrograph at the KPNO 2.1-m or with the RC spectrograph at the CTIO 1.5-m. The master PN table contains atlas data and an image link. A selected object's spectrum is displayed in a zoomable window; line identification templates are provided. In addition to the spectra themselves, the website also contains a brief discussion of PNe as astronomical objects and as contributors to our understanding of stellar evolution. We envision that this website, which concentrates a large amount of data in one place, will be of interest to a variety of users: researchers might need to check the spectrum of a particular object of interest; the non-specialist astronomer might simply be interested in perusing such a collection of spectra; and...

  19. Vibrational spectra of ordered perovskites

    NARCIS (Netherlands)

    Corsmit, A.F.; Hoefdraad, H.E.; Blasse, G.

    1972-01-01

    The vibrational spectra of the molecular M6+O6 (M = Mo, Te, W) group in ordered perovskites of the type Ba2M2+M6+O6 are reported. These groups have symmetry Oh, whereas their site symmetry is also Oh. An assignment of the internal vibrations is presented.

  20. Spectra of sodium aluminate solutions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The UV spectra of sodium aluminate solutions were obtained in the sodium oxide concentration range from 59 to 409 g/L and the caustic ratio range from 1.5 to 4.0 to reveal the structure characteristics of them. It is found that a new peak appears at about 370 nm besides peaks at about 220 and 266 nm in all solutions. The new peak is strongly favored by high hydroxide concentration and high caustic ratio. And it only appears when the solutions are prepared by dissolving sodium hydroxide and aluminum hydroxide.In addition, the IR and Raman spectra of sodium aluminate solutions with high alkali concentration and high caustic ratio were measured, and the UV spectra of aqueous solutions of Al(H2O)63+ and AlF63- were measured as well. According to the crystal field theory in coordination chemistry as well as the above spectra characteristics, this new peak at about 370 nm is determined as the evidence of a new species of aluminate ion with a coordination number of 6.

  1. Chemical abundances in the protoplanetary disc LV 2 (Orion) - II. High-dispersion VLT observations and microjet properties

    Science.gov (United States)

    Tsamis, Y. G.; Walsh, J. R.

    2011-11-01

    Integral field spectroscopy of the LV 2 proplyd is presented taken with the Very Large Telescope (VLT)/FLAMES Argus array at an angular resolution of 0.31 × 0.31 arcsec2 and velocity resolutions down to 2 km s-1 pixel-1. Following subtraction of the local M42 emission, the spectrum of LV 2 is isolated from the surrounding nebula. We measured the heliocentric velocities and widths of a number of lines detected in the intrinsic spectrum of the proplyd, as well as in the adjacent Orion nebula falling within a 6.6 × 4.2 arcsec2 field of view. It is found that far-ultraviolet to optical collisional lines with critical densities, Ncr, ranging from 103 to 109 cm-3 suffer collisional de-excitation near the rest velocity of the proplyd correlating tightly with their critical densities. Lines of low Ncr are suppressed the most. The bipolar jet arising from LV 2 is spectrally and spatially well detected in several emission lines. We compute the [O III] electron temperature profile across LV 2 in velocity space and measure steep temperature variations associated with the red-shifted lobe of the jet, possibly being due to a shock discontinuity. From the velocity-resolved analysis the ionized gas near the rest frame of LV 2 has Te= 9200 ± 800 K and Ne˜ 106 cm-3, while the red-shifted jet lobe has Te≈ 9000-104 K and Ne˜ 106-107 cm-3. The jet flow is highly ionized but contains dense semineutral clumps emitting neutral oxygen lines. The abundances of N+, O2 +, Ne2 +, Fe2 +, S+and S2 +are measured for the strong red-shifted jet lobe. Iron in the core of LV 2 is depleted by 2.54 dex with respect to solar as a result of sedimentation on dust, whereas the efficient destruction of dust grains in the fast microjet raises its Fe abundance to at least 30 per cent solar. Sulphur does not show evidence of significant depletion on dust, but its abundance both in the core and the jet is only about half solar. Based on observations made with ESO telescopes at the Paranal Observatory

  2. First light of the VLT planet finder SPHERE. I. Detection and characterization of the substellar companion GJ 758 B

    Science.gov (United States)

    Vigan, A.; Bonnefoy, M.; Ginski, C.; Beust, H.; Galicher, R.; Janson, M.; Baudino, J.-L.; Buenzli, E.; Hagelberg, J.; D'Orazi, V.; Desidera, S.; Maire, A.-L.; Gratton, R.; Sauvage, J.-F.; Chauvin, G.; Thalmann, C.; Malo, L.; Salter, G.; Zurlo, A.; Antichi, J.; Baruffolo, A.; Baudoz, P.; Blanchard, P.; Boccaletti, A.; Beuzit, J.-L.; Carle, M.; Claudi, R.; Costille, A.; Delboulbé, A.; Dohlen, K.; Dominik, C.; Feldt, M.; Fusco, T.; Gluck, L.; Girard, J.; Giro, E.; Gry, C.; Henning, T.; Hubin, N.; Hugot, E.; Jaquet, M.; Kasper, M.; Lagrange, A.-M.; Langlois, M.; Le Mignant, D.; Llored, M.; Madec, F.; Martinez, P.; Mawet, D.; Mesa, D.; Milli, J.; Mouillet, D.; Moulin, T.; Moutou, C.; Origné, A.; Pavlov, A.; Perret, D.; Petit, C.; Pragt, J.; Puget, P.; Rabou, P.; Rochat, S.; Roelfsema, R.; Salasnich, B.; Schmid, H.-M.; Sevin, A.; Siebenmorgen, R.; Smette, A.; Stadler, E.; Suarez, M.; Turatto, M.; Udry, S.; Vakili, F.; Wahhaj, Z.; Weber, L.; Wildi, F.

    2016-03-01

    GJ 758 B is a brown dwarf companion to a nearby (15.76%) solar-type, metal-rich (M / H = + 0.2 dex) main-sequence star (G9V) that was discovered with Subaru/HiCIAO in 2009. From previous studies, it has drawn attention as being the coldest (~600 K) companion ever directly imaged around a neighboring star. We present new high-contrast data obtained during the commissioning of the SPHERE instrument at the Very Large Telescope (VLT). The data was obtained in Y-, J-, H-, and Ks-bands with the dual-band imaging (DBI) mode of IRDIS, thus providing a broad coverage of the full near-infrared (near-IR) range at higher contrast and better spectral sampling than previously reported. In this new set of high-quality data, we report the re-detection of the companion, as well as the first detection of a new candidate closer-in to the star. We use the new eight photometric points for an extended comparison of GJ 758 B with empirical objects and four families of atmospheric models. From comparison to empirical object, we estimate a T8 spectral type, but none of the comparison objects can accurately represent the observed near-IR fluxes of GJ 758 B. From comparison to atmospheric models, we attribute a Teff = 600 ± 100 K, but we find that no atmospheric model can adequately fit all the fluxes of GJ 758 B. The lack of exploration of metal enrichment in model grids appears as a major limitation that prevents an accurate estimation of the companion physical parameters. The photometry of the new candidate companion is broadly consistent with L-type objects, but a second epoch with improved photometry is necessary to clarify its status. The new astrometry of GJ 758 B shows a significant proper motion since the last epoch. We use this result to improve the determination of the orbital characteristics using two fitting approaches: Least-Squares Monte Carlo and Markov chain Monte Carlo. We confirm the high-eccentricity of the orbit (peak at 0.5), and find a most likely semi-major axis of

  3. Shadows cast on the transition disk of HD 135344B. Multiwavelength VLT/SPHERE polarimetric differential imaging

    Science.gov (United States)

    Stolker, T.; Dominik, C.; Avenhaus, H.; Min, M.; de Boer, J.; Ginski, C.; Schmid, H. M.; Juhasz, A.; Bazzon, A.; Waters, L. B. F. M.; Garufi, A.; Augereau, J.-C.; Benisty, M.; Boccaletti, A.; Henning, Th.; Langlois, M.; Maire, A.-L.; Ménard, F.; Meyer, M. R.; Pinte, C.; Quanz, S. P.; Thalmann, C.; Beuzit, J.-L.; Carbillet, M.; Costille, A.; Dohlen, K.; Feldt, M.; Gisler, D.; Mouillet, D.; Pavlov, A.; Perret, D.; Petit, C.; Pragt, J.; Rochat, S.; Roelfsema, R.; Salasnich, B.; Soenke, C.; Wildi, F.

    2016-11-01

    Context. The protoplanetary disk around the F-type star HD 135344B (SAO 206462) is in a transition stage and shows many intriguing structures both in scattered light and thermal (sub-)millimeter emission which are possibly related to planet formation processes. Aims: We aim to study the morphology and surface brightness of the disk in scattered light to gain insight into the innermost disk regions, the formation of protoplanets, planet-disk interactions traced in the surface and midplane layers, and the dust grain properties of the disk surface. Methods: We have carried out high-contrast polarimetric differential imaging (PDI) observations with VLT/SPHERE and obtained polarized scattered light images with ZIMPOL in the R and I-bands and with IRDIS in the Y and J-bands. The scattered light images and surface brightness profiles are used to study in detail structures in the disk surface and brightness variations. We have constructed a 3D radiative transfer model to support the interpretation of several detected shadow features. Results: The scattered light images reveal with unprecedented angular resolution and sensitivity the spiral arms as well as the 25 au cavity of the disk. Multiple shadow features are discovered on the outer disk with one shadow only being present during the second observation epoch. A positive surface brightness gradient is observed in the stellar irradiation corrected (r2-scaled) images in southwest direction possibly due to an azimuthally asymmetric perturbation of the temperature and/or surface density by the passing spiral arms. The disk integrated polarized flux, normalized to the stellar flux, shows a positive trend towards longer wavelengths which we attribute to large (2πa ≳ λ) aggregate dust grains in the disk surface. Part of the non-azimuthal polarization signal in the Uφ image of the J-band observation can be attributed to multiple scattering in the disk. Conclusions: The detected shadow features and their possible variability

  4. Testing giant planet formation in the transitional disk of SAO 206462 using deep VLT/SPHERE imaging

    Science.gov (United States)

    Maire, A.-L.; Stolker, T.; Messina, S.; Müller, A.; Biller, B. A.; Currie, T.; Dominik, C.; Grady, C. A.; Boccaletti, A.; Bonnefoy, M.; Chauvin, G.; Galicher, R.; Millward, M.; Pohl, A.; Brandner, W.; Henning, T.; Lagrange, A.-M.; Langlois, M.; Meyer, M. R.; Quanz, S. P.; Vigan, A.; Zurlo, A.; van Boekel, R.; Buenzli, E.; Buey, T.; Desidera, S.; Feldt, M.; Fusco, T.; Ginski, C.; Giro, E.; Gratton, R.; Hubin, N.; Lannier, J.; Le Mignant, D.; Mesa, D.; Peretti, S.; Perrot, C.; Ramos, J. R.; Salter, G.; Samland, M.; Sissa, E.; Stadler, E.; Thalmann, C.; Udry, S.; Weber, L.

    2017-05-01

    Context. The SAO 206462 (HD 135344B) disk is one of the few known transitional disks showing asymmetric features in scattered light and thermal emission. Near-infrared scattered-light images revealed two bright outer spiral arms and an inner cavity depleted in dust. Giant protoplanets have been proposed to account for the disk morphology. Aims: We aim to search for giant planets responsible for the disk features and, in the case of non-detection, to constrain recent planet predictions using the data detection limits. Methods: We obtained new high-contrast and high-resolution total intensity images of the target spanning the Y to the K bands (0.95-2.3 μm) using the VLT/SPHERE near-infrared camera and integral field spectrometer. Results: The spiral arms and the outer cavity edge are revealed at high resolutions and sensitivities without the need for aggressive image post-processing techniques, which introduce photometric biases. We do not detect any close-in companions. For the derivation of the detection limits on putative giant planets embedded in the disk, we show that the knowledge of the disk aspect ratio and viscosity is critical for the estimation of the attenuation of a planet signal by the protoplanetary dust because of the gaps that these putative planets may open. Given assumptions on these parameters, the mass limits can vary from 2-5 to 4-7 Jupiter masses at separations beyond the disk spiral arms. The SPHERE detection limits are more stringent than those derived from archival NaCo/L' data and provide new constraints on a few recent predictions of massive planets (4-15 MJ) based on the spiral density wave theory. The SPHERE and ALMA data do not favor the hypotheses on massive giant planets in the outer disk (beyond 0.6''). There could still be low-mass planets in the outer disk and/or planets inside the cavity. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programmes 095.C

  5. Phobos surface spectra mineralogical modeling

    Science.gov (United States)

    Pajola, M.; Lazzarin, M.; Dalle Ore, C. M.; Cruikshank, D. P.; Roush, T. L.; Pendleton, Y.; Bertini, I.; Magrin, S.; Carli, C.; La Forgia, F.; Barbieri, C.

    2014-04-01

    A mineralogical model composed of a mixture of Tagish Lake meteorite (TL) and Pyroxene Glass (PM80) was presented in [1] to explain the surface reflectance of Phobos from 0.25 to 4.0 μm. The positive results we obtained, when comparing the OSIRIS data [2] extended in wavelength to include the [3,4] spectra, forced us to perform a wider comparison between our TL-PM80 model and the CRISM and OMEGA Phobos spectra presented in [5]. Such spectra cover three different regions of interest (ROIs) situated in the Phobos sub-Mars hemisphere: the interior of the Stickney crater, its eastern rim, and its proximity terrain southeast of the Reldresal crater. We decided to vary the percentage mixture of the components of our model (80% TL, 20% PM80), between pure TL and pure PM80, by means of the radiative transfer code based on the [6] formulation of the slab approximation. Once this spectral range was derived, see Fig. 1, we attempted to compare it with the [5] spectra between 0.4 and 2.6 μm, i.e. below the thermal emitted radiation, to see if any spectral match was possible. We observed that CRISM scaled spectra above 1.10 μm fall within pure Tagish Lake composition and the [1] model. The CRISM data below 1.10 μm present more discrepancies with our models, in particular for the Stickney's rim spectrum. Nevertheless the TL and PM80 components seem to be good mineralogical candidates on Phobos. We performed the same analysis with the OMEGA data and, again, we found out that the Stickney's rim spectrum lies out of our model range, while the two remaining spectra still lie between pure TL and 80% TL - 20% PM80, but indicating that a different, more complicated mixture is expected in order to explain properly both the spectral trend and the possible absorption bands located above 2.0 μm. Within this analysis, we point out that a big fraction of TL material (modeled pure or present with a minimum percentage of 80% mixed together with 20% PM80) seems to explain Phobos spectral

  6. HST/WFC3 Observations of Uranus' 2014 storm clouds and comparison with VLT/SINFONI and IRTF/SpeX observations

    CERN Document Server

    Irwin, Patrick G J; Simon, Amy A; Orton, G S; Toledo, Daniel

    2016-01-01

    Observations of Uranus were made on the 8/9th November with HST/WFC3 at a time when a huge cloud complex was present at 30 - 40N. We imaged Uranus in seven filters spanning 467 - 924 nm, and analysed these observations with the NEMESIS radiative-transfer and retrieval code. The same system was also observed in the H-band with VLT/SINFONI ON 31st October and 11th November (Irwin et al., 2016). To constrain the background cloud particle sizes and scattering properties we conducted a limb-darkening analysis of the background cloud structure at 30-40N by simultaneously fitting: a) these HST/OPAL observations at a range of zenith angles; b) the VLT/SINFONI observations at a range of zenith angles; and c) IRTF/SpeX observations made in 2009 (Irwin et al., 2015). We find that the observations are well modelled with a three-component cloud comprised of: 1) a vertically thin, but optically thick 'deep' tropospheric cloud at a pressure of ~2 bars; 2) a methane-ice cloud at the methane-condensation level with variable v...

  7. Ruling out unresolved binaries in five transitional disks VLT/NACO: deep 2.12 and 1.75 {\\mu}m narrow-band imaging

    CERN Document Server

    Vicente, Silvia; Hartung, Markus; Bouy, Herve; Huelamo, Nuria; Artigau, Etienne; Augereau, Jean-Charles; van Dishoeck, Ewine; Olofsson, Johan; Oliveira, Isa; Prusti, Timo

    2011-01-01

    Aims. We aim at detecting the presence of companions inside the inner hole/gap region of a sample of five well known transitional disks using spatially-resolved imaging in the near-IR with the VLT/NACO/S13 camera, which probes projected distances from the primary of typically 0.1 to 7 arcsec. The sample includes the stars DoAr 21, HD 135344B (SAO 206462), HR 4796A, T Cha, and TW Hya, spanning ages of less than 1 to 10 Myr, spectral types of A0 to K7, and hole/gap outer radii of 4 to 100 AU. Methods. In order to enhance the contrast and to avoid saturation at the core of the point-spread function (PSF), we use narrow-band filters at 1.75 and 2.12 {\\mu}m. The "locally optimized combination of images" (LOCI) algorithm is applied for an optimal speckle noise removal and PSF subtraction, providing an increase of 0.5-1.5 mag in contrast over the classic method. Results. With the proviso that we could have missed companions owing to unfavorable projections, the VLT/NACO observations rule out the presence of unresolv...

  8. The VLT-FLAMES Tarantula Survey XVII. Physical and wind properties of massive stars at the top of the main sequence

    CERN Document Server

    Bestenlehner, Joachim M; Vink, Jorick S; Najarro, F; de Koter, A; Sana, H; Evans, C J; Crowther, P A; Hénault-Brunet, V; Herrero, A; Langer, N; Schneider, F R N; Simón-Díaz, S; Taylor, W D; Walborn, N R

    2014-01-01

    The evolution and fate of very massive stars (VMS) is tightly connected to their mass-loss properties. Their initial and final masses differ significantly as a result of mass loss. VMS have strong stellar winds and extremely high ionising fluxes, which are thought to be critical sources of both mechanical and radiative feedback in giant Hii regions. However, how VMS mass-loss properties change during stellar evolution is poorly understood. In the framework of the VLT-Flames Tarantula Survey (VFTS), we explore the mass-loss transition region from optically thin O to denser WNh star winds, thereby testing theoretical predictions. To this purpose we select 62 O, Of, Of/WN, and WNh stars, an unprecedented sample of stars with the highest masses and luminosities known. We perform a spectral analysis of optical VFTS as well as near-infrared VLT/SINFONI data using the non-LTE radiative transfer code CMFGEN to obtain stellar and wind parameters. For the first time, we observationally resolve the transition between op...

  9. The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits: II- Survey description, results and performances

    CERN Document Server

    Chauvin, G; Bonnefoy, M; Desidera, S; Bonavita, M; Mesa, D; Boccaletti, A; Buenzli, E; Carson, J; Delorme, P; Hagelberg, J; Montagnier, G; Mordasini, C; Quanz, S P; Segransan, D; Thalmann, C; Beuzit, J -L; Biller, B; Covino, E; Feldt, M; Girard, J; Gratton, R; Henning, T; Kasper, M; Lagrange, A -M; Messina, S; Meyer, M; Mouillet, D; Moutou, C; Reggianni, M; Schlieder, J E; Zurlo, A

    2014-01-01

    In anticipation of the VLT/SPHERE planet imager guaranteed time programs, we have conducted a preparatory survey of 86 stars between 2009 and 2013 in order to identify new faint comoving companions to ultimately carry out a comprehensive analysis of the occurence of giant planets and brown dwarf companions at wide (10-2000 AU) orbits around young, solar-type stars. We used NaCo at VLT to explore the occurrence rate of giant planets and brown dwarfs between typically 0.1 and 8''. Diffraction-limited observations in H-band combined with angular differential imaging enabled us to reach primary star-companion brightness ratios as small as 10-6 at 1.5''. 12 systems were resolved as new binaries, including the discovery of a new white dwarf companion to the star HD8049. Around 34 stars, at least one companion candidate was detected in the observed field of view. More than 400 faint sources were detected, 90% of them in 4 crowded fields. With the exception of HD8049B, we did not identify any new comoving companions....

  10. Clumpy dust clouds and extended atmosphere of the AGB star W Hya revealed with VLT/SPHERE-ZIMPOL and VLTI/AMBER

    CERN Document Server

    Ohnaka, Keiichi; Hofmann, Karl-Heinz

    2016-01-01

    We present visible polarimetric imaging observations of the well-studied AGB star W Hya taken with VLT/SPHERE-ZIMPOL as well as high spectral resolution long-baseline interferometric observations with the AMBER instrument of the Very Large Telescope Interferometer (VLTI). We observed W Hya with VLT/SPHERE-ZIMPOL at three wavelengths in the continuum (645, 748, and 820 nm), in the Halpha line at 656.3 nm, and in the TiO band at 717 nm. The VLTI/AMBER observations were carried out in the wavelength region of the CO first overtone lines near 2.3 micron with a spectral resolution of 12000. Taking advantage of the polarimetric imaging capability of SPHERE-ZIMPOL combined with the superb adaptive optics performance, we have succeeded in spatially resolving three clumpy dust clouds located at ~50 mas (~2 Rstar) from the central star, revealing dust formation very close to the star. The AMBER data in the individual CO lines suggest a molecular outer atmosphere extending to ~3 Rstar. Furthermore, the SPHERE-ZIMPOL ima...

  11. Apodization in high-contrast long-slit spectroscopy. II. Concept validation and first on-sky results with VLT/SPHERE

    CERN Document Server

    Vigan, A; Dohlen, K; Beuzit, J -L; Costille, A; Caillat, A; Baruffolo, A; Blanchard, P; Carle, M; Ferrari, M; Fusco, T; Gluck, L; Hugot, E; Jaquet, M; Langlois, M; Mignant, D Le; Llored, M; Madec, F; Mouillet, D; Origné, A; Puget, P; Salasnich, B; Sauvage, J -F

    2015-01-01

    Spectral characterization of young, giant exoplanets detected by direct imaging is one of the tasks of the new generation of high-contrast imagers. For this purpose, the VLT/SPHERE instrument includes a unique long-slit spectroscopy (LSS) mode coupled with Lyot coronagraphy in its infrared dual-band imager and spectrograph (IRDIS). The performance of this mode is intrinsically limited by the use of a non-optimal coronagraph, but in a previous work we demonstrated that it could be significantly improved at small inner-working angles using the stop-less Lyot coronagraph (SLLC). We now present the development, testing, and validation of the first SLLC prototype for VLT/SPHERE. Based on the transmission profile previously proposed, the prototype was manufactured using microdots technology and was installed inside the instrument in 2014. The transmission measurements agree well with the specifications, except in the very low transmissions (<5% in amplitude). The performance of the SLLC is tested in both imaging...

  12. Eigenvectors of optimal color spectra.

    Science.gov (United States)

    Flinkman, Mika; Laamanen, Hannu; Tuomela, Jukka; Vahimaa, Pasi; Hauta-Kasari, Markku

    2013-09-01

    Principal component analysis (PCA) and weighted PCA were applied to spectra of optimal colors belonging to the outer surface of the object-color solid or to so-called MacAdam limits. The correlation matrix formed from this data is a circulant matrix whose biggest eigenvalue is simple and the corresponding eigenvector is constant. All other eigenvalues are double, and the eigenvectors can be expressed with trigonometric functions. Found trigonometric functions can be used as a general basis to reconstruct all possible smooth reflectance spectra. When the spectral data are weighted with an appropriate weight function, the essential part of the color information is compressed to the first three components and the shapes of the first three eigenvectors correspond to one achromatic response function and to two chromatic response functions, the latter corresponding approximately to Munsell opponent-hue directions 9YR-9B and 2BG-2R.

  13. Phonon spectra in quantum wires

    Directory of Open Access Journals (Sweden)

    Ilić Dušan

    2007-01-01

    Full Text Available Green's function method, adjusted to bound crystalline structures, was applied to obtain the phonon dispersion law in quantum wires. The condition of the existence of small mechanical atom movements defining phonon spectra can be found by solving the secular equation. This problem was presented graphically for different boundary parameters. The presence of boundaries, as well as the change of boundary parameters, leads to the appearance of new properties of the layered structure. The most important feature is that, beside the allowed energy zones (which are continuous as in the bulk structure, zones of forbidden states appear. Different values of the boundary parameters lead to the appearance of lower and upper energy gaps, or dispersion branches spreading out of the bulk energy zone. The spectra of phonons in corresponding unbound structures were correlated to those in bound structures.

  14. Extremely metal-poor stars in classical dwarf spheroidal galaxies : Fornax, Sculptor, and Sextans

    NARCIS (Netherlands)

    Tafelmeyer, M.; Jablonka, P.; Hill, V.; Shetrone, M.; Tolstoy, E.; Irwin, M. J.; Battaglia, G.; Helmi, A.; Starkenburg, E.; Venn, K. A.; Abel, T.; Francois, P.; Kaufer, A.; North, P.; Primas, F.; Szeifert, T.

    2010-01-01

    We present the results of a dedicated search for extremely metal-poor stars in the Fornax, Sculptor, and Sextans dSphs. Five stars were selected from two earlier VLT/Giraffe and HET/HRS surveys and subsequently followed up at high spectroscopic resolution with VLT/UVES. All of them turned out to hav

  15. Extremely metal-poor stars in classical dwarf spheroidal galaxies : Fornax, Sculptor, and Sextans

    NARCIS (Netherlands)

    Tafelmeyer, M.; Jablonka, P.; Hill, V.; Shetrone, M.; Tolstoy, E.; Irwin, M. J.; Battaglia, G.; Helmi, A.; Starkenburg, E.; Venn, K. A.; Abel, T.; Francois, P.; Kaufer, A.; North, P.; Primas, F.; Szeifert, T.

    2010-01-01

    We present the results of a dedicated search for extremely metal-poor stars in the Fornax, Sculptor, and Sextans dSphs. Five stars were selected from two earlier VLT/Giraffe and HET/HRS surveys and subsequently followed up at high spectroscopic resolution with VLT/UVES. All of them turned out to hav

  16. M-Band Spectra of Dust Embedded Sources at the Galactic Center

    CERN Document Server

    Moultaka, J; Schödel, R

    2009-01-01

    The goal of the present paper is to investigate the circumstellar material around the brightest dust-enshrouded sources in the central stellar cluster of the Milky Way. Observations have been carried out at the European Southern Observatory's Very Large Telescope on Paranal, Chile. We have used the long wavelength (LWS3) low resolution (LR) spectroscopic mode of the ISAAC camera at the VLT in the spectral range of the M filter from 4.4micron to 5.1micron. The use of a slit width of 0.6" implied a spectral resolution of R=l/Dl=800 (Dv=375 km/s). These observations resulted in M-band spectra of 15 bright sources in the central stellar cluster of the Milky Way. In addition to gaseous 12^CO (4.666 micron) and 13^CO (4.77 micron) vibration-rotational absorptions, we detect a strong absorption due to a mixture of polar and apolar CO ice (centered at 4.675 micron). In the shorter wavelength absorption wing there is an absorption feature due to XCN at 4.62 micron. The XCN absorption is strongest toward the M2 supergi...

  17. Resolving the inner regions of the HD 97048 circumstellar disk with VLT/NACO polarimetric differential imaging

    Science.gov (United States)

    Quanz, S. P.; Birkmann, S. M.; Apai, D.; Wolf, S.; Henning, T.

    2012-02-01

    Context. Circumstellar disks are the cradles of planetary systems and their physical and chemical properties directly influence the planet formation process. Because most planets supposedly form in the inner disk regions, i.e., within a few tens of AU, it is crucial to study circumstellar disks on these scales to constrain the conditions for planet formation. Aims: Our aims are to characterize the inner regions of the circumstellar disk around the young Herbig Ae/Be star HD 97048 in polarized light. Methods: We used VLT/NACO to observe HD 97048 in polarimetric differential imaging (PDI) mode in the H and Ks band. This technique offers high-contrast capabilities at very small inner working angles and probes the dust grains on the surface layer of the disk that act as the scattering surface. Results: We spatially resolve the disk around HD 97048 in polarized flux in both filters on scales between ~0.1″-1.0″ corresponding to the inner ~16-160 AU. Fitting isophots to the flux calibrated H-band image between 13-14 mag/arcsec2 and 14-15 mag/arcsec2, we derive an apparent disk inclination angle of 34° ± 5° and 47° ± 2°, respectively. The disk position angle in both brightness regimes is almost identical and roughly 80°. Along the disk major axis the surface brightness of the polarized flux drops from ~11 mag/arcsec2 at ~0.1″ (~16 AU) to ~15.3 mag/arcsec2 at ~ 1.0″ (~160 AU). The brightness profiles along the major axis are fitted with power-laws falling off as ∝ r - 1.78 ± 0.02 in H and ∝ r - 2.34 ± 0.04 in Ks. Because the surface brightness decreases more rapidly in Ks compared to H, the disks becomes relatively bluer at larger separations, possibly indicating changing dust grain properties as a function of radius. Conclusions: We imaged for the first time the inner ~0.1″-1.0″ (~16-160 AU) of the surface layer of the HD 97048 circumstellar disk in scattered light, which demonstrates the power of ground-based imaging polarimetry. Our data fill an

  18. Analysing degeneracies in networks spectra

    CERN Document Server

    Marrec, Loïc

    2016-01-01

    Many real-world networks exhibit a high degeneracy at few eigenvalues. We show that a simple transformation of the network's adjacency matrix provides an understanding of? the origins of occurrence of high multiplicities in the networks spectra. We find that the eigenvectors associated with the degenerate eigenvalues shed light on the structures contributing to the degeneracy. Since these degeneracies are rarely observed in model graphs, we present results for various cancer networks. This approach gives an opportunity to search for structures contributing to degeneracy which might have an important role in a network.

  19. Rotational spectra and molecular structure

    CERN Document Server

    Wollrab, James E

    1967-01-01

    Physical Chemistry, A Series of Monographs: Rotational Spectra and Molecular Structure covers the energy levels and rotational transitions. This book is divided into nine chapters that evaluate the rigid asymmetric top molecules and the nuclear spin statistics for asymmetric tops. Some of the topics covered in the book are the asymmetric rotor functions; rotational transition intensities; classes of molecules; nuclear spin statistics for linear molecules and symmetric tops; and classical appearance of centrifugal and coriolis forces. Other chapters deal with the energy levels and effects of ce

  20. Gamma-ray burst spectra

    Science.gov (United States)

    Teegarden, B. J.

    1982-01-01

    A review of recent results in gamma-ray burst spectroscopy is given. Particular attention is paid to the recent discovery of emission and absorption features in the burst spectra. These lines represent the strongest evidence to date that gamma-ray bursts originate on or near neutron stars. Line parameters give information on the temperature, magnetic field and possibly the gravitational potential of the neutron star. The behavior of the continuum spectrum is also discussed. A remarkably good fit to nearly all bursts is obtained with a thermal-bremsstrahlung-like continuum. Significant evolution is observed of both the continuum and line features within most events.

  1. Infrared Spectra of Polycyclic Aromatic Hydrocarbons (PAHs)

    Science.gov (United States)

    Bauschlicher, Charles W., Jr.; Bakes, E. L. O.

    2000-01-01

    We have computed the synthetic infrared spectra of some polycyclic aromatic hydrocarbons containing up to 54 carbon atoms. The species studied include ovalene, circumcoronene, dicoronylene, and hexabenzocoronene. We report spectra for anions, neutrals, cations, and multiply charged cations.

  2. Searching for swept-up Hydrogen and Helium in the late-time spectra of 11 nearby Type Ia supernovae

    CERN Document Server

    Maguire, Kate; Sullivan, Mark; Mazzali, Paolo A

    2015-01-01

    The direct detection of a stellar system that explodes as a Type Ia supernova (SN Ia) has not yet been successful. Various indirect methods have been used to investigate SN Ia progenitor systems but none have produced conclusive results. A prediction of single-degenerate models is that H- (or He-) rich material from the envelope of the companion star should be swept up by the SN ejecta in the explosion. Seven SNe Ia have been analysed to date looking for signs of H-rich material in their late-time spectra and none were detected. We present results from new late-time spectra of 11 SNe Ia obtained at the VLT using XShooter and FORS2. We present the tentative detection of H-alpha emission for SN 2013ct, corresponding to ~0.007 Msun of stripped/ablated companion star material (under the assumptions of the spectral modelling). This mass is significantly lower than expected for single-degenerate scenarios, suggesting that >0.1 Msun of H-rich is present but not observed. We do not detect H-alpha emission in the othe...

  3. First light of the VLT planet finder SPHERE. IV. Physical and chemical properties of the planets around HR8799

    CERN Document Server

    Bonnefoy, M; Baudino, J L; Lucas, P; Mesa, D; Maire, A -L; Vigan, A; Galicher, R; Homeier, D; Marocco, F; Gratton, R; Chauvin, G; Allard, F; Desidera, S; Kasper, M; Moutou, C; Lagrange, A -M; Baruffolo, A; Baudrand, J; Beuzit, J -L; Boccaletti, A; Cantalloube, F; Carbillet, M; Charton, J; Claudi, R U; Costille, A; Dohlen, K; Dominik, C; Fantinel, D; Feautrier, P; Feldt, M; Fusco, T; Gigan, P; Girard, J H; Gluck, L; Gry, C; Henning, T; Janson, M; Langlois, M; Madec, F; Magnard, Y; Maurel, D; Mawet, D; Meyer, M R; Milli, J; Moeller-Nilsson, O; Mouillet, D; Pavlov, A; Perret, D; Pujet, P; Quanz, S P; Rochat, S; Rousset, G; Roux, A; Salasnich, B; Salter, G; Sauvage, J -F; Schmid, H M; Sevin, A; Soenke, C; Stadler, E; Turatto, M; Udry, S; Vakili, F; Wahhaj, Z; Wildi, F

    2015-01-01

    The system of four planets around HR8799 offers a unique opportunity to probe the physics and chemistry at play in the atmospheres of self-luminous young (~30 Myr) planets. We recently obtained new photometry of the four planets and low-resolution (R~30) spectra of HR8799 d and e with the SPHERE instrument (paper III). In this paper (paper IV), we compare the available spectra and photometry of the planets to known objects and atmospheric models (BT-SETTL14, Cloud-AE60, Exo-REM) to characterize the atmospheric properties of the planets. We find that HR8799d and e properties are well reproduced by those of L6-L8 dusty dwarfs discovered in the field, among which some are candidate members of young nearby associations. No known object reproduces well the properties of planets b and c. Nevertheless, we find that the spectra and WISE photometry of peculiar and/or young early-T dwarfs reddened by submicron grains made of corundum, iron, enstatite, or forsterite successfully reproduce the SED of these two planets. O...

  4. Fine Spectra of Symmetric Toeplitz Operators

    Directory of Open Access Journals (Sweden)

    Muhammed Altun

    2012-01-01

    Full Text Available The fine spectra of 2-banded and 3-banded infinite Toeplitz matrices were examined by several authors. The fine spectra of n-banded triangular Toeplitz matrices and tridiagonal symmetric matrices were computed in the following papers: Altun, “On the fine spectra of triangular toeplitz operators” (2011 and Altun, “Fine spectra of tridiagonal symmetric matrices” (2011. Here, we generalize those results to the (2+1-banded symmetric Toeplitz matrix operators for arbitrary positive integer .

  5. Duality properties between spectra and tilings

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Spectra and tilings play an important role in analysis and geometry respectively.The relations between spectra and tilings have bafied the mathematicians for a long time.Many conjectures,such as the Fuglede conjecture,are placed on the establishment of relations between spectra and tilings,although there are no desired results.In the present paper we derive some characteristic properties of spectra and tilings which highlight certain duality properties between them.

  6. Fast computation of morphological area pattern spectra

    NARCIS (Netherlands)

    Meijster, Arnold; Wilkinson, Michael H.F.

    2001-01-01

    An area based counterpart of the binary structural opening spectra is developed It is shown that these area opening and closing spectra can be computed using an adaptation of Tarjan's union-find algorithm These spectra provide rotation, translation, and scale invariant pattern vectors for texture

  7. Multiscale climate emulator of multimodal wave spectra: MUSCLE-spectra

    Science.gov (United States)

    Rueda, Ana; Hegermiller, Christie A.; Antolinez, Jose A. A.; Camus, Paula; Vitousek, Sean; Ruggiero, Peter; Barnard, Patrick L.; Erikson, Li H.; Tomás, Antonio; Mendez, Fernando J.

    2017-02-01

    Characterization of multimodal directional wave spectra is important for many offshore and coastal applications, such as marine forecasting, coastal hazard assessment, and design of offshore wave energy farms and coastal structures. However, the multivariate and multiscale nature of wave climate variability makes this complex problem tractable using computationally expensive numerical models. So far, the skill of statistical-downscaling model-based parametric (unimodal) wave conditions is limited in large ocean basins such as the Pacific. The recent availability of long-term directional spectral data from buoys and wave hindcast models allows for development of stochastic models that include multimodal sea-state parameters. This work introduces a statistical downscaling framework based on weather types to predict multimodal wave spectra (e.g., significant wave height, mean wave period, and mean wave direction from different storm systems, including sea and swells) from large-scale atmospheric pressure fields. For each weather type, variables of interest are modeled using the categorical distribution for the sea-state type, the Generalized Extreme Value (GEV) distribution for wave height and wave period, a multivariate Gaussian copula for the interdependence between variables, and a Markov chain model for the chronology of daily weather types. We apply the model to the southern California coast, where local seas and swells from both the Northern and Southern Hemispheres contribute to the multimodal wave spectrum. This work allows attribution of particular extreme multimodal wave events to specific atmospheric conditions, expanding knowledge of time-dependent, climate-driven offshore and coastal sea-state conditions that have a significant influence on local nearshore processes, coastal morphology, and flood hazards.

  8. VLT adaptive optics imaging of QSO host galaxies and close environment at z ~2.5: results from a pilot program

    CERN Document Server

    Falomo, R; Scarpa, R; Treves, A

    2004-01-01

    We report ESO-VLT near-infrared adaptive optics imaging of one radio-loud (PKS 0113-283) and two radio-quiet (Q 0045-3337 and Q 0101-337) QSOs at z > 2. In the first case, we are able to resolve the QSO and find that it is hosted by an elliptical of absolute magnitude M(K) = -27.6. For the other two objects, no extended emission has been unambiguously detected. This result, though restricted to a single object, extends up to z ~2.5 the finding that cosmic evolution of radio-loud QSO hosts follows the trend expected for luminous and massive spheroids undergoing passive evolution. For Q 0045-3337, our high resolution images show that it is located 1.2 arcsec from a K = 17.5 foreground disc galaxy, which may act as a gravitational lens, since the QSO most probably lies within the galaxy Einstein radius.

  9. The VLT-FLAMES Tarantula Survey X: Evidence for a bimodal distribution of rotational velocities for the single early B-type stars

    CERN Document Server

    Dufton, P L; Dunstall, P R; Evans, C J; Brott, I; de Mink, S E; Howarth, I D; Kennedy, M; McEvoy, C; Potter, A T; Ramírez-Agudelo, O H; Sana, H; Simón-Díaz, S; Taylor, W; Vink, J S

    2012-01-01

    Aims: Projected rotational velocities (\\vsini) have been estimated for 334 targets in the VLT-FLAMES Tarantula survey that do not manifest significant radial velocity variations and are not supergiants. They have spectral types from approximately O9.5 to B3. The estimates have been analysed to infer the underlying rotational velocity distribution, which is critical for understanding the evolution of massive stars. Methods: Projected rotational velocities were deduced from the Fourier transforms of spectral lines, with upper limits also being obtained from profile fitting. For the narrower lined stars, metal and non-diffuse helium lines were adopted, and for the broader lined stars, both non-diffuse and diffuse helium lines; the estimates obtained using the different sets of lines are in good agreement. The uncertainty in the mean estimates is typically 4% for most targets. The iterative deconvolution procedure of Lucy has been used to deduce the probability density distribution of the rotational velocities. R...

  10. The VLT/NaCo Large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits: I- Sample definition and characterization

    CERN Document Server

    Desidera, S; Messina, S; Carson, J; Hagelberg, J; Schlieder, J E; Biazzo, K; Alcala, J M; Chauvin, G; Vigan, A; Beuzit, J L; Bonavita, M; Bonnefoy, M; Delorme, P; D'Orazi, V; Esposito, M; Feldt, M; Girardi, L; Gratton, R; Henning, T; Lagrange, A M; Lanzafame, A C; Launhardt, R; Marmier, M; Melo, C; Meyer, M; Mouillet, D; Moutou, C; Segransan, D; Udry, S; Zaidi, C M

    2014-01-01

    Young, nearby stars are ideal targets to search for planets using the direct imaging technique. The determination of stellar parameters is crucial for the interpretation of imaging survey results particularly since the luminosity of substellar objects has a strong dependence on system age. We have conducted a large program with NaCo at the VLT in order to search for planets and brown dwarfs in wide orbits around 86 stars. A large fraction of the targets observed with NaCo were poorly investigated in the literature. We performed a study to characterize the fundamental properties (age, distance, mass) of the stars in our sample. To improve target age determinations, we compiled and analyzed a complete set of age diagnostics. We measured spectroscopic parameters and age diagnostics using dedicated observations acquired with FEROS and CORALIE spectrographs at La Silla Observatory. We also made extensive use of archival spectroscopic data and results available in the literature. Additionally, we exploited photomet...

  11. High-Cadence, High-Contrast Imaging for Exoplanet Mapping: Observations of the HR 8799 Planets with VLT/SPHERE Satellite Spot-Corrected Relative Photometry

    CERN Document Server

    Apai, Daniel; Skemer, Andrew; Hanson, Jake R; Lagrange, Anne-Marie; Biller, Beth A; Bonnefoy, Mickael; Buenzli, Esther; Vigan, Arthur

    2016-01-01

    Time-resolved photometry is an important new probe of the physics of condensate clouds in extrasolar planets and brown dwarfs. Extreme adaptive optics systems can directly image planets, but precise brightness measurements are challenging. We present VLT/SPHERE high-contrast, time-resolved broad H-band near-infrared photometry for four exoplanets in the HR 8799 system, sampling changes from night to night over five nights with relatively short integrations. The photospheres of these four planets are often modeled by patchy clouds and may show large-amplitude rotational brightness modulations. Our observations provide high-quality images of the system. We present a detailed performance analysis of different data analysis approaches to accurately measure the relative brightnesses of the four exoplanets. We explore the information in satellite spots and demonstrate their use as a proxy for image quality. While the brightness variations of the satellite spots are strongly correlated, we also identify a second-ord...

  12. Scikit-spectra: Explorative Spectroscopy in Python

    Directory of Open Access Journals (Sweden)

    Adam Hughes

    2015-06-01

    Full Text Available Scikit-spectra is an intuitive framework for explorative spectroscopy in Python. Scikit-spectra leverages the Pandas library for powerful data processing to provide datastructures and an API designed for spectroscopy. Utilizing the new IPython Notebook widget system, scikit-spectra is headed towards a GUI when you want it, API when you need it approach to spectral analysis. As an application, analysis is presented of the surface-plasmon resonance shift in a solution of gold nanoparticles induced by proteins binding to the gold’s surface. Please refer to the scikit-spectra website for full documentation and support: http://hugadams.github.io/scikit-spectra/

  13. Analysis of multi-layer ERBS spectra

    Energy Technology Data Exchange (ETDEWEB)

    Marmitt, G.G. [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Rosa, L.F.S. [Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Nandi, S.K. [Electronic Materials Engineering Department, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2611 (Australia); Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh); Vos, M., E-mail: maarten.vos@anu.edu.au [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia)

    2015-07-15

    Highlights: • Electron Rutherford backscattering (ERBS) spectra are presented. • The spectra are fitted based on physical meaningful quantities. • Very consistent results are obtained for spectra taken under different conditions. • This establishes that ERBS can be used to measure film thicknesses. - Abstract: A systematic way of analysis of multi-layer electron Rutherford backscattering spectra is described. The approach uses fitting in terms of physical meaningful parameters. Simultaneous analysis then becomes possible for spectra taken at different incoming energies and measurement geometries. Examples are given to demonstrate the level of detail that can be resolved by this technique.

  14. Neutron and photon spectra in LINACs.

    Science.gov (United States)

    Vega-Carrillo, H R; Martínez-Ovalle, S A; Lallena, A M; Mercado, G A; Benites-Rengifo, J L

    2012-12-01

    A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10(-6) and 1 MeV. Neutron and the Bremsstrahlung spectra show the same features regardless of the linac voltage.

  15. Action spectra of zebrafish cone photoreceptors.

    Directory of Open Access Journals (Sweden)

    Duco Endeman

    Full Text Available Zebrafish is becoming an increasingly popular model in the field of visual neuroscience. Although the absorption spectra of its cone photopigments have been described, the cone action spectra were still unknown. In this study we report the action spectra of the four types of zebrafish cone photoreceptors, determined by measuring voltage responses upon light stimulation using whole cell patch clamp recordings. A generic template of photopigment absorption spectra was fit to the resulting action spectra in order to establish the maximum absorption wavelength, the A2-based photopigment contribution and the size of the β-wave of each cone-type. Although in general there is close correspondence between zebrafish cone action- and absorbance spectra, our data suggest that in the case of MWS- and LWS-cones there is appreciable contribution of A2-based photopigments and that the β-wave for these cones is smaller than expected based on the absorption spectra.

  16. Graviton spectra in string cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Galluccio, Massimo [Osservatorio Astronomico di Roma (Roma-IT); Litterio, Marco [Istituto Astronomico dell' Universita (Roma-IT); Occhionero, Franco [Osservatorio Astronomico di Roma (Roma-IT)

    1996-08-01

    We propose to uncover the signature of a stringy era in the primordial Universe by searching for a prominent peak in the relic graviton spectrum. This feature, which in our specific model terminates an ω³ increase and initiates an ω⁻⁷ decrease, is induced during the so far overlooked bounce of the scale factor between the collapsing deflationary era (or pre-Big Bang) and the expanding inflationary era (or post-Big Bang). We evaluate both analytically and numerically the frequency and the intensity of the peak and we show that they may likely fall in the realm of the new generation of interferometric detectors. The existence of a peak is at variance with ordinarily monotonic (either increasing or decreasing) graviton spectra of canonical cosmologies; its detection would therefore offer strong support to string cosmology.

  17. Graviton Spectra in String Cosmology

    CERN Document Server

    Galluccio, M; Occhionero, F; Galluccio, Massimo; Litterio, Marco; Occhionero, Franco

    1997-01-01

    We propose to uncover the signature of a stringy era in the primordial Universe by searching for a prominent peak in the relic graviton spectrum. This feature, which in our specific model terminates an $\\omega^3$ increase and initiates an $\\omega^{-7}$ decrease, is induced during the so far overlooked bounce of the scale factor between the collapsing deflationary era (or pre-Big Bang) and the expanding inflationary era (or post-Big Bang). We evaluate both analytically and numerically the frequency and the intensity of the peak and we show that they may likely fall in the realm of the new generation of interferometric detectors. The existence of a peak is at variance with ordinarily monotonic (either increasing or decreasing) graviton spectra of canonical cosmologies; its detection would therefore offer strong support to string cosmology.

  18. [Vibrational spectra of Corallium elatius].

    Science.gov (United States)

    Fan, Lu-wei; Zhang, Yan; Hu, Yang

    2013-09-01

    Corallium elatius, which has unique color distribution characteristic, is the most important species of Taiwan precious corals. EPMA, XRD, FTIR and Laser Raman detective methods were used to study the chemical, mineral composition and spectra characteristics of Corallium elatius. The result of EPMA, XRD and FTIR shows the high-Mg calcite mineral componentand the stable minor chemical constituents of the samples. Meanwhile, the cell parameter indicates the lattice distortion and the preferred orientation of calcite grain caused by organic matter. The red part of the samples shows a different Raman spectrum from that of the white part, located at 1517/1128 cm(-1) and 1296/1016 cm(-1). Raman scattering measurement reveals the relationship between the organic matter and color.

  19. Características clínicas de 64 indivíduos portadores de uveítis posterior activa presumiblemente toxoplásmica en Pernambuco Clinical characteristics of 64 individuals carrying active posterior presumptively toxoplasmic uveitis, in Pernambuco

    Directory of Open Access Journals (Sweden)

    Maria Isabel Lynch

    2008-02-01

    Full Text Available OBJETIVO: Describir características clínicas de uveítis posterior activa, presumiblemente por Toxoplasma gondii (UPAPT en portadores de lesión típica. Estudio tranversal. MÉTODOS: 64 portadores de UPAPT con retinocorroiditis cicatrizada y lesión satélite activa, mayores de 10 años, inmunocompetentes, examinados en Permambuco, Brazil. Se analizó: sexo, edad, color de la piel, procedencia, uveítis anteriores, agudeza visual, presión ocular y exámen ocular. RESULTADOS: Masculino en 52%. Edad media 29 años (±10,87. Piel blanca en 68,8%. Domicilio en la área metropolitana en 80,4%. Primer episodio de uveítis en 56,2%. Media de visión en ojo afectado 20/200. Presión ocular media 14,5 mmHg (±7,64 en ojo afectado. Conjuntiva hiperemiada en 29,7%. Alteraciones corneales en 51,6%. Células en el humor acuoso en 67,2%. Sinéquias posteriores en 6,2%. Compromiso vítreo en 100%. Vasculitis retiniana en 45,3%. Lesiones localizads en la zona I de Holland en 42,2%, siendo de tamaño igual o mayor de un diámetro de disco en 90,6%. Neuritis en 28,2%. CONCLUSIÓN: UPAPT afecta adultos jóvenes, siendo el síntoma principal la disminución de la visión. Presión ocular media normal. Compromiso vítreo en todos los casos. Com mayor frequencia las lesiones fueron mayores de un diámetro de disco localizadas en la zona I de Holland.PURPOSE: To describe clinical characteristics of posterior active uveitis presumptively by Toxoplasma gondii (PAUPT in patients with typical lesion. Tranversal study. METHODS: Sixty-four patients with retinochoroiditis scatter and active satellite lesions examined in Pernambuco, Brazil. All were older than 10 years and immunocompetent. Gender, age, skin color, and residence were recorded. Previous uveitis, visual accuracy, intraocular pressure (IOP, and ocular examination were analyzed. RESULTS: 52% were males, most of them with white skin (68.8%. Mean age 29 years (±10.87. Eighty-four percent of the patients lived

  20. The VLT-FLAMES Tarantula Survey . XXIV. Stellar properties of the O-type giants and supergiants in 30 Doradus

    Science.gov (United States)

    Ramírez-Agudelo, O. H.; Sana, H.; de Koter, A.; Tramper, F.; Grin, N. J.; Schneider, F. R. N.; Langer, N.; Puls, J.; Markova, N.; Bestenlehner, J. M.; Castro, N.; Crowther, P. A.; Evans, C. J.; García, M.; Gräfener, G.; Herrero, A.; van Kempen, B.; Lennon, D. J.; Maíz Apellániz, J.; Najarro, F.; Sabín-Sanjulián, C.; Simón-Díaz, S.; Taylor, W. D.; Vink, J. S.

    2017-04-01

    Context. The Tarantula region in the Large Magellanic Cloud (LMC) contains the richest population of spatially resolved massive O-type stars known so far. This unmatched sample offers an opportunity to test models describing their main-sequence evolution and mass-loss properties. Aims: Using ground-based optical spectroscopy obtained in the framework of the VLT-FLAMES Tarantula Survey (VFTS), we aim to determine stellar, photospheric and wind properties of 72 presumably single O-type giants, bright giants and supergiants and to confront them with predictions of stellar evolution and of line-driven mass-loss theories. Methods: We apply an automated method for quantitative spectroscopic analysis of O stars combining the non-LTE stellar atmosphere model fastwind with the genetic fitting algorithm pikaia to determine the following stellar properties: effective temperature, surface gravity, mass-loss rate, helium abundance, and projected rotational velocity. The latter has been constrained without taking into account the contribution from macro-turbulent motions to the line broadening. Results: We present empirical effective temperature versus spectral subtype calibrations at LMC-metallicity for giants and supergiants. The calibration for giants shows a +1kK offset compared to similar Galactic calibrations; a shift of the same magnitude has been reported for dwarfs. The supergiant calibrations, though only based on a handful of stars, do not seem to indicate such an offset. The presence of a strong upturn at spectral type O3 and earlier can also not be confirmed by our data. In the spectroscopic and classical Hertzsprung-Russell diagrams, our sample O stars are found to occupy the region predicted to be the core hydrogen-burning phase by state-of-the-art models. For stars initially more massive than approximately 60 M⊙, the giant phase already appears relatively early on in the evolution; the supergiant phase develops later. Bright giants, however, are not

  1. The VLT LEGA-C Spectroscopic Survey: The Physics of Galaxies at a Lookback Time of 7 Gyr

    CERN Document Server

    van der Wel, A; Bezanson, R; Pacifici, C; Gallazzi, A; Franx, M; Munoz-Mateos, J C; Bell, E F; Brammer, G; Charlot, S; Chauke, P; Labbe, I; Maseda, M V; Muzzin, A; Rix, H -W; Sobral, D; van de Sande, J; van Dokkum, P G; Wild, V; Wolf, C

    2016-01-01

    The Large Early Galaxy Census (LEGA-C) is a Public Spectroscopic Survey of $\\sim3200$ $K$-band selected galaxies at redshifts $z=0.6-1.0$ with stellar masses M_star > 1e10M_sun, conducted with VIMOS on ESO's Very Large Telescope. The survey is embedded in the COSMOS field ($R.A. = 10h00$; $Dec.=+2\\deg$). The 20-hour long integrations produce high-$S/N$ continuum spectra that reveal ages, metallicities and velocity dispersions of the stellar populations. LEGA-C's unique combination of sample size and depth will enable us for the first time to map the stellar content at large look-back time, across galaxies of different types and star-formation activity. Observations started in December 2014 and are planned to be completed by mid 2018, with early data releases of the spectra and value-added products. In this paper we present the science case, the observing strategy, an overview of the data reduction process and data products, and a first look at the relationship between galaxy structure and spectral properties,...

  2. VizieR Online Data Catalog: NGC 2808 AGB and RGB stars Na abundance (Wang+, 2016)

    Science.gov (United States)

    Wang, Y.; Primas, F.; Charbonnel, C.; van der Swaelmen, M.; Bono, G.; Chantereau, W.; Zhao, G.

    2016-05-01

    The high-resolution spectra of our sample of AGB and RGB stars in the Galactic globular cluster NGC 2808 were obtained with the high-resolution multi-object spectrograph FLAMES, mounted on ESO/VLT-UT2. A combined mode was used where the brightest five objects was observed with UVES-fibre and the remaining targets with GIRAFFE/Medusa. The basic information of our sample stars are listed in Table 2, including the evolutionary phase, instrument used for observation, coordinates, photometry and barycentric radial velocity. Our Fe abundances were derived from the equivalent widths of Fe lines, while the Na abundances were determined with spectra synthesis. Both FeI and Na abundances have been corrected for the non-LTE effect. In Table 4 we show the derived stellar parameters of our sample stars, and the Na abundances are shown in Table 6. (3 data files).

  3. The heavily polluted atmosphere of the DAZ white dwarf GALEX J193156.8+011745

    CERN Document Server

    Vennes, S; Nemeth, P

    2010-01-01

    We report on the discovery of a new heavily polluted white dwarf. The DAZ white dwarf GALEX J193156.8+011745 was identified in a joint GALEX/GSC survey of ultraviolet-excess objects. Optical spectra obtained at ESO NTT show strong absorption lines of magnesium and silicon and a detailed abundance analysis based on VLT-Kueyen UVES spectra reveal super-solar abundances of silicon and magnesium, and near-solar abundances of oxygen, calcium, and iron. The overall abundance pattern bears the signature of ongoing accretion onto the white dwarf atmosphere. The infrared spectral energy distribution shows an excess in the H and K bands likely associated with the accretion source.

  4. Looking at the bright side - The story of AA Dor as revealed by its cool companion

    CERN Document Server

    Vučković, Maja; Németh, Peter; Bloemen, Steven; Pápics, Peter I

    2015-01-01

    Irradiation effects in close binaries are crucial for a reliable determination of system parameters and understanding the close binary evolution. We study irradiated light originating from the low mass component of an eclipsing system comprising a hot subdwarf primary and a low mass companion, to precisely interpret their high precision photometric and spectroscopic data, and accurately determine their system and surface parameters. We re-analyse the archival VLT/UVES spectra of AA Dor system where irradiation features have already been detected. After removing the predominant contribution of the hot subdwarf primary, the residual spectra reveal more than 100 emission lines from the heated side of the secondary with maximum intensity close to the phases around secondary eclipse. We analyse 22 narrow emission lines of the irradiated secondary, mainly of OII, with a few CII lines. Their phase profiles constrain the emission region of the heated side to a radius $\\geq$ 95% of the radius of the secondary. The sha...

  5. A fast and portable Re-Implementation of Piskunov and Valenti's Optimal-Extraction Algorithm with improved Cosmic-Ray Removal and Optimal Sky Subtraction

    CERN Document Server

    Ritter, A; Parker, Q A

    2013-01-01

    We present a fast and portable re-implementation of Piskunov and Valenti's optimal-extraction algorithm (Piskunov & Valenti, 2002} in C/C++ together with full uncertainty propagation, improved cosmic-ray removal, and an optimal background-subtraction algorithm. This re-implementation can be used with IRAF and most existing data-reduction packages and leads to signal-to-noise ratios close to the Poisson limit. The algorithm is very stable, operates on spectra from a wide range of instruments (slit spectra and fibre feeds), and has been extensively tested for VLT/UVES, ESO/CES, ESO/FEROS, NTT/EMMI, NOT/ALFOSC, STELLA/SES, SSO/WiFeS, and finally, P60/SEDM-IFU data.

  6. A Fast and Portable Reimplementation of Piskunov and Valenti’s Optimal-Extraction Algorithm with Improved Cosmic-Ray Removal and Optimal Sky Subtraction

    Science.gov (United States)

    Ritter, A.; Hyde, E. A.; Parker, Q. A.

    2014-02-01

    We present a fast and portable re-implementation of Piskunov and Valenti's optimal-extraction algorithm (Piskunov & Valenti, 2002} in C/C++ together with full uncertainty propagation, improved cosmic-ray removal, and an optimal background-subtraction algorithm. This re-implementation can be used with IRAF and most existing data-reduction packages and leads to signal-to-noise ratios close to the Poisson limit. The algorithm is very stable, operates on spectra from a wide range of instruments (slit spectra and fibre feeds), and has been extensively tested for VLT/UVES, ESO/CES, ESO/FEROS, NTT/EMMI, NOT/ALFOSC, STELLA/SES, SSO/WiFeS, and finally, P60/SEDM-IFU data.

  7. The Spitzer Atlas of Stellar Spectra

    CERN Document Server

    Ardila, David R; Makowiecki, Wojciech; Stauffer, John; Song, Inseok; Rho, Jeonghee; Fajardo-Acosta, Sergio; Hoard, D W; Wachter, Stefanie

    2010-01-01

    We present the Spitzer Atlas of Stellar Spectra (SASS), which includes 159 stellar spectra (5 to 32 mic; R~100) taken with the Infrared Spectrograph on the Spitzer Space Telescope. This Atlas gathers representative spectra of a broad section of the Hertzsprung-Russell diagram, intended to serve as a general stellar spectral reference in the mid-infrared. It includes stars from all luminosity classes, as well as Wolf-Rayet (WR) objects. Furthermore, it includes some objects of intrinsic interest, like blue stragglers and certain pulsating variables. All the spectra have been uniformly reduced, and all are available online. For dwarfs and giants, the spectra of early-type objects are relatively featureless, dominated by Hydrogen lines around A spectral types. Besides these, the most noticeable photospheric features correspond to water vapor and silicon monoxide in late-type objects and methane and ammonia features at the latest spectral types. Most supergiant spectra in the Atlas present evidence of circumstell...

  8. Reflectance spectra of subarctic lichens

    Science.gov (United States)

    Petzold, Donald E.; Goward, Samuel N.

    1988-01-01

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the midlatitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 microns, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future.

  9. Interpretation of Nitroindolinospirobenzothiopyran Vibrational Spectra

    Science.gov (United States)

    Gladkov, L. L.; Khamchukov, Yu. D.; Lyubimov, A. V.

    2016-05-01

    The structures of four possible stereoisomers of the closed form of photochromic nitroindolinospirobenzothiopyran (NISTP) {1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzothiopyran-2,2'-(2H)-indoline]} were determined by the DFT method. The geometry of the most stable isomer was defined. Nitro-substitution changes mainly the lengths of bonds formed by S and N with spiro-atom Cs. According to the calculations, the CsS bond changes most and lengthens by 0.019 Å. It is shown that the S atom has large displacement amplitudes in normal modes assigned to Raman lines at 230, 285, 360, and 575 cm-1 and weak IR bands at 467 and 577 cm-1. Oscillations involving the nitro group are very active in Raman and IR spectra. Their frequencies are slightly lower than similar frequencies of nitrobenzene and nitroindolinospirobenzopyran, indicating a higher degree of vibrational coupling of the NO2 group with the NISTP molecular skeleton.

  10. Functional Regression for Quasar Spectra

    CERN Document Server

    Ciollaro, Mattia; Freeman, Peter; Genovese, Christopher; Lei, Jing; O'Connell, Ross; Wasserman, Larry

    2014-01-01

    The Lyman-alpha forest is a portion of the observed light spectrum of distant galactic nuclei which allows us to probe remote regions of the Universe that are otherwise inaccessible. The observed Lyman-alpha forest of a quasar light spectrum can be modeled as a noisy realization of a smooth curve that is affected by a `damping effect' which occurs whenever the light emitted by the quasar travels through regions of the Universe with higher matter concentration. To decode the information conveyed by the Lyman-alpha forest about the matter distribution, we must be able to separate the smooth `continuum' from the noise and the contribution of the damping effect in the quasar light spectra. To predict the continuum in the Lyman-alpha forest, we use a nonparametric functional regression model in which both the response and the predictor variable (the smooth part of the damping-free portion of the spectrum) are function-valued random variables. We demonstrate that the proposed method accurately predicts the unobserv...

  11. On non-forking spectra

    CERN Document Server

    Chernikov, Artem; Shelah, Saharon

    2012-01-01

    Non-forking is one of the most important notions in modern model theory capturing the idea of a generic extension of a type (which is a far-reaching generalization of the concept of a generic point of a variety). To a countable first-order theory we associate its non-forking spectrum - a function of two cardinals kappa and lambda giving the supremum of the possible number of types over a model of size lambda that do not fork over a sub-model of size kappa. This is a natural generalization of the stability function of a theory. We make progress towards classifying the non-forking spectra. On the one hand, we show that the possible values a non-forking spectrum may take are quite limited. On the other hand, we develop a general technique for constructing theories with a prescribed non-forking spectrum, thus giving a number of examples. In particular, we answer negatively a question of Adler whether NIP is equivalent to bounded non-forking. In addition, we answer a question of Keisler regarding the number of cut...

  12. Electronic Spectra of Chevreul's Salts

    Directory of Open Access Journals (Sweden)

    Silva Luciana A. da

    2002-01-01

    Full Text Available The isomorphic series of double sulfites with empirical formula Cu2SO3.MSO3.2H 2O (where M is Cu, Fe, Mn, or Cd have been prepared from the Cu(II replacement by transition metal ions such as Mn(II, Fe(II and Cd(II ions in Chevreul's salt, Cu2SO3.CuSO3.2H 2O. As a consequence, the isomorphic species present distinct colors. Molecular modeling calculations were carried out for the dimeric [CuI2(SO3 2(SO32]6- center. The electronic spectra of the Chevreul's salt consist of a charge-transfer band around 425 nm associated with the [CuI2(SO3 2(SO32]6- chromophore and two ligand field transitions at 785 and 1000 nm involving the Jahn-Teller splitting of the Cu(II levels. An additional intervalence-transfer band, responsible for its characteristic red color, can be found at 500 nm. The replacement of the Cu(II ions for Fe(II, Mn(II and Cd(II does not eliminate the absorption band at 425 nm, supporting its assignment as a charge-transfer transition centered on the Cu(I sites; while the original band at 500 nm disappears, in agreement with its intervalence transfer nature.

  13. Structure of high-resolution NMR spectra

    CERN Document Server

    Corio, PL

    2012-01-01

    Structure of High-Resolution NMR Spectra provides the principles, theories, and mathematical and physical concepts of high-resolution nuclear magnetic resonance spectra.The book presents the elementary theory of magnetic resonance; the quantum mechanical theory of angular momentum; the general theory of steady state spectra; and multiple quantum transitions, double resonance and spin echo experiments.Physicists, chemists, and researchers will find the book a valuable reference text.

  14. A study of ice response spectra

    Institute of Scientific and Technical Information of China (English)

    LIU Chunguang; JIA Lingling

    2009-01-01

    Some problems concerning the ice forces and ice response spectra are studied from both theoretical and practical points of view. On the basis of structural analysis,the analysis method of ice response spectra is proposed, since it plays an important role in the prediction of maximum structural response in cold regions. And it is illustrated that it is easy to study the structural response to ice using the ice response spectra.

  15. Circumstellar Molecular Spectra towards Evolved Stars

    CERN Document Server

    Bakker, E J

    1997-01-01

    In this paper we discuss the relevance of, and possible scientific gains which can be acquired from studying circumstellar molecular spectra toward evolved stars. Where can we expect circumstellar molecular spectra, why would we want to study these spectra, which molecules might be present, and what can we learn from these studies? We present an overview of reported detections, and discuss some of the results.

  16. Calculation of reactor antineutrino spectra in TEXONO

    CERN Document Server

    Chen Dong Liang; Mao Ze Pu; Wong, T H

    2002-01-01

    In the low energy reactor antineutrino physics experiments, either for the researches of antineutrino oscillation and antineutrino reactions, or for the measurement of abnormal magnetic moment of antineutrino, the flux and the spectra of reactor antineutrino must be described accurately. The method of calculation of reactor antineutrino spectra was discussed in detail. Furthermore, based on the actual circumstances of NP2 reactors and the arrangement of detectors, the flux and the spectra of reactor antineutrino in TEXONO were worked out

  17. First light of the VLT planet finder SPHERE. IV. Physical and chemical properties of the planets around HR8799

    Science.gov (United States)

    Bonnefoy, M.; Zurlo, A.; Baudino, J. L.; Lucas, P.; Mesa, D.; Maire, A.-L.; Vigan, A.; Galicher, R.; Homeier, D.; Marocco, F.; Gratton, R.; Chauvin, G.; Allard, F.; Desidera, S.; Kasper, M.; Moutou, C.; Lagrange, A.-M.; Antichi, J.; Baruffolo, A.; Baudrand, J.; Beuzit, J.-L.; Boccaletti, A.; Cantalloube, F.; Carbillet, M.; Charton, J.; Claudi, R. U.; Costille, A.; Dohlen, K.; Dominik, C.; Fantinel, D.; Feautrier, P.; Feldt, M.; Fusco, T.; Gigan, P.; Girard, J. H.; Gluck, L.; Gry, C.; Henning, T.; Janson, M.; Langlois, M.; Madec, F.; Magnard, Y.; Maurel, D.; Mawet, D.; Meyer, M. R.; Milli, J.; Moeller-Nilsson, O.; Mouillet, D.; Pavlov, A.; Perret, D.; Pujet, P.; Quanz, S. P.; Rochat, S.; Rousset, G.; Roux, A.; Salasnich, B.; Salter, G.; Sauvage, J.-F.; Schmid, H. M.; Sevin, A.; Soenke, C.; Stadler, E.; Turatto, M.; Udry, S.; Vakili, F.; Wahhaj, Z.; Wildi, F.

    2016-03-01

    Context. The system of fourplanets discovered around the intermediate-mass star HR8799 offers a unique opportunity to test planet formation theories at large orbital radii and to probe the physics and chemistry at play in the atmospheres of self-luminous young (~30 Myr) planets. We recently obtained new photometry of the four planets and low-resolution (R ~ 30) spectra of HR8799 d and e with the SPHERE instrument (Paper III). Aims: In this paper (Paper IV), we aim to use these spectra and available photometry to determine how they compare to known objects, what the planet physical properties are, and how their atmospheres work. Methods: We compare the available spectra, photometry, and spectral energy distribution (SED) of the planets to field dwarfs and young companions. In addition, we use the extinction from corundum, silicate (enstatite and forsterite), or iron grains likely to form in the atmosphere of the planets to try to better understand empirically the peculiarity of their spectrophotometric properties. To conclude, we use three sets of atmospheric models (BT-SETTL14, Cloud-AE60, Exo-REM) to determine which ingredients are critically needed in the models to represent the SED of the objects, and to constrain their atmospheric parameters (Teff, log g, M/H). Results: We find that HR8799d and e properties are well reproduced by those of L6-L8 dusty dwarfs discovered in the field, among which some are candidate members of young nearby associations. No known object reproduces well the properties of planets b and c. Nevertheless, we find that the spectra and WISE photometry of peculiar and/or young early-T dwarfs reddened by submicron grains made of corundum, iron, enstatite, or forsterite successfully reproduce the SED of these planets. Our analysis confirms that only the Exo-REM models with thick clouds fit (within 2σ) the whole set of spectrophotometric datapoints available for HR8799 d and e for Teff = 1200 K, log g in the range 3.0-4.5, and M/H = +0.5. The

  18. Spectra of Velocity components over Complex Terrain

    DEFF Research Database (Denmark)

    Panofsky, H. A.; Larko, D.; Lipschut, R.

    1982-01-01

    Spectra have been measured over a variety of types of complex terrain: on tops of hills and escarpments, over land downstream of a water surface, and over rolling terrain. Differences between spectra over many types of complex terrain, and over uniform terrain, can be explained by these hypotheses...... is horizontal, and decrease when the flow is uphill, for the longitudinal velocity component only. Since vertical-velocity spectra contain relatively less low wavenumber energy than horizontal-velocity spectra, energetic vertical-velocity fluctuations tend to be in equilibrium with local terrain....

  19. Optical absorption spectra of Ag-11 isomers

    DEFF Research Database (Denmark)

    Martinez, Jose Ignacio; Fernandez, E. M.

    2009-01-01

    The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground-stale confi......The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground...

  20. Chlorambucil and cyclosporine A in Brazilian patients with Behçet's disease uveitis: a retrospective study Clorambucil e ciclosporina A em pacientes brasileiros com doença de Behçet e uveíte: estudo retrospectivo

    Directory of Open Access Journals (Sweden)

    Juliana Marques Zaghetto

    2010-02-01

    Full Text Available PURPOSE: To assess the efficacy and side effects of immunosuppressive therapy in patients with Behçet's disease uveitis. METHODS: A nonrandomized retrospective case-series study analyzed data from 22 patients with Behçet's disease uveitis, from a single Uveitis Service, São Paulo, Brazil (period 1978-2007, under systemic chlorambucil and/or cyclosporine A, for at least 6 months with a minimum one-year follow-up. Drug efficacy was measured by reduction in relapse rate and reduction of prednisone dose. RESULTS: Patients (10M/12F mean age was 29 (range 10-43 years-old at the onset of uveitis. The median duration of followup was 11 (range 1-29 years-old. Chlorambucil (2-6 mg/day was used in 13 patients and cyclosporine A (3-5 mg/kg/day in 9 patients at initiation. Drugs were switched because of no effectiveness or side-effects. Chlorambucil was effective in 78.5% (11/14 and induced disease remission in 43% (6/14 of patients, whereas cyclosporine A was effective in 57% (8/14 of patients. Chlorambucil and cyclosporine A were discontinued due to side effects in 21% (leucopenia and in 57% of patients (nephrotoxicity, 36% and gastrointestinal complications, 21%, respectively. No case of late malignancy was observed. 36% (16/44 of eyes had final visual acuity OBJETIVOS: Avaliar a eficácia e efeitos colaterais da terapia imunossupressora em pacientes com uveíte associada à doença de Behçet. MÉTODOS: Estudo retrospectivo não randomizado no qual são analisados dados de 22 pacientes com uveíte associada à doença de Behçet que utilizaram clorambucil e/ou ciclosporina A sistêmica por período mínimo de 6 meses, acompanhados pelo período mínimo de 1 ano, num único Serviço de Uveíte, São Paulo, Brasil (período 1978-2007. A eficácia do tratamento foi avaliada pela redução no número de recidivas da inflamação e pela redução na dose diária de prednisona. RESULTADOS: Vinte e dois pacientes (10 M/12 F, com idade média de 29 (varia

  1. The manifold spectra and morphologies of EROs

    CERN Document Server

    Cimatti, A; Cassata, P; Pignatelli, E; Fasano, G; Vernet, J; Fomalont, E; Kellermann, K; Zamorani, G; Mignoli, M; Pozzetti, L; Renzini, A; Alighieri, S S; Franceschini, A; Giallongo, E; Fontana, A

    2003-01-01

    Deep VLT optical spectroscopy, HST+ACS (GOODS) imaging and VLA observations are used to unveil the nature of a complete sample of 47 EROs with R-Ks>5 and Ks<20. The spectroscopic redshift completeness is 62%. Morphological classification was derived for each ERO through visual inspection and surface brightness profile fitting. Three main ERO morphological types are found: E/S0 galaxies (30-37%), spiral-like (24-46%) and irregular systems (17-39%). The only ERO detected in the radio is likely to host an obscured AGN. The average radio luminosity of the star-forming EROs undetected in the radio implies star formation rates of the order of 33 Msun yr^-1. The colors, redshifts and masses of the E/S0 galaxy subsample imply a minimum formation redshift z_f \\sim 2. With this z_f there is enough time to have old and massive stellar spheroids already assembled at z \\sim 1. We verify that the R-Ks vs. J-Ks color diagram is efficient in segregating old and dusty-star-forming EROs.

  2. The VLT-FLAMES Tarantula Survey. XVII. Physical and wind properties of massive stars at the top of the main sequence

    Science.gov (United States)

    Bestenlehner, J. M.; Gräfener, G.; Vink, J. S.; Najarro, F.; de Koter, A.; Sana, H.; Evans, C. J.; Crowther, P. A.; Hénault-Brunet, V.; Herrero, A.; Langer, N.; Schneider, F. R. N.; Simón-Díaz, S.; Taylor, W. D.; Walborn, N. R.

    2014-10-01

    The evolution and fate of very massive stars (VMS) is tightly connected to their mass-loss properties. Their initial and final masses differ significantly as a result of mass loss. VMS have strong stellar winds and extremely high ionising fluxes, which are thought to be critical sources of both mechanical and radiative feedback in giant H ii regions. However, how VMS mass-loss properties change during stellar evolution is poorly understood. In the framework of the VLT-Flames Tarantula Survey (VFTS), we explore the mass-loss transition region from optically thin O star winds to denser WNh Wolf-Rayet star winds, thereby testing theoretical predictions. To this purpose we select 62 O, Of, Of/WN, and WNh stars, an unprecedented sample of stars with the highest masses and luminosities known. We perform a spectral analysis of optical VFTS as well as near-infrared VLT/SINFONI data using the non-LTE radiative transfer code CMFGEN to obtain both stellar and wind parameters. For the first time, we observationally resolve the transition between optically thin O star winds and optically thick hydrogen-rich WNh Wolf-Rayet winds. Our results suggest the existence of a "kink" between both mass-loss regimes, in agreement with recent Monte Carlo simulations. For the optically thick regime, we confirm the steep dependence on the classical Eddington factor Γe from previous theoretical and observational studies. The transition occurs on the main sequence near a luminosity of 106.1L⊙, or a mass of 80 ... 90 M⊙. Above this limit, we find that - even when accounting for moderate wind clumping (with fv = 0.1) - wind mass-loss rates are enhanced with respect to standard prescriptions currently adopted in stellar evolution calculations. We also show that this results in substantial helium surface enrichment. Finally, based on our spectroscopic analyses, we are able to provide the most accurate ionising fluxes for VMS known to date, confirming the pivotal role of VMS in ionising and

  3. Thermoluminescence spectra measured with a Michelson interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Haschberger, P. (Technische Univ. Muenchen (Germany). Lehrstuhl fuer Elektrische Messtechnik)

    1991-01-01

    A Michelson interferometer was redesigned to prove its capabilities in the measurement of short-lived, low-intensity thermoluminescence spectra. Interferograms are collected during heating up the thermoluminescent probe in a heater plate. A personal computer controls the data acquisition and processes the Fourier transform. As the results show, even a comparatively simple and limited setup leads to relevant and reproducible spectra. (author).

  4. Aircraft Measurements of Atmospheric Kinetic Energy Spectra

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Lilly, D. K.

    1983-01-01

    Wind velocity data obtained from a jet airliner are used to construct kinetic energy spectra over the range of wavelengths from 2.5 to 2500 km. The spectra exhibit an approximate -5/3 slope for wavelengths of less than about 150 km, steepening to about -2.2 at larger scales. These results support...

  5. Moessbauer Spectra of Clays and Ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, F. E.; Wagner, U. [Technische Universitaet Muenchen (Germany)

    2004-06-15

    The physical, chemical and mineralogical aspects of the use of Moessbauer spectroscopy in studies of clay-based ceramics are described. Moessbauer spectra of pottery clays fired under oxidising, reducing and changing conditions are explained, and the possibilities of using Moessbauer spectra to derive information on the firing temperatures and the kiln atmosphere during firing in antiquity are discussed and illustrated by examples.

  6. Aircraft Measurements of Atmospheric Kinetic Energy Spectra

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Lilly, D. K.

    1983-01-01

    Wind velocity data obtained from a jet airliner are used to construct kinetic energy spectra over the range of wavelengths from 2.5 to 2500 km. The spectra exhibit an approximate -5/3 slope for wavelengths of less than about 150 km, steepening to about -2.2 at larger scales. These results support...

  7. Tunneling spectra of graphene on copper unraveled

    DEFF Research Database (Denmark)

    Zhang, Xin; Stradi, Daniele; Liu, Lei

    2016-01-01

    mechanisms, etc. The interpretation of the spectra can be complicated, however. Specifically for graphene grown on copper, there have been conflicting reports of tunneling spectra. A clear understanding of the mechanisms behind the variability is desired. In this work, we have revealed that the root cause...

  8. POLLUX : a database of synthetic stellar spectra

    CERN Document Server

    Palacios, A; Josselin, E; Martins, F; Plez, B; Belmas, M; Lebre, A

    2010-01-01

    Synthetic spectra are needed to determine fundamental stellar and wind parameters of all types of stars. They are also used for the construction of theoretical spectral libraries helpful for stellar population synthesis. Therefore, a database of theoretical spectra is required to allow rapid and quantitative comparisons to spectroscopic data. We provide such a database offering an unprecedented coverage of the entire Hertzsprung-Russell diagram. We present the POLLUX database of synthetic stellar spectra. For objects with Teff 25 000 K). Their spectra are computed with CMF_FLUX. Both high resolution (R>150 000) optical spectra in the range 3 000 to 12 000 A and spectral energy distributions extending from the UV to near--IR ranges are presented. These spectra cover the HR diagram at solar metallicity. We propose a wide variety of synthetic spectra for various types of stars in a format that is compliant with the Virtual Observatory standards. A user--friendly web interface allows an easy selection of spectra...

  9. General Notes on Processes and Their Spectra

    Directory of Open Access Journals (Sweden)

    Gustav Cepciansky

    2012-01-01

    Full Text Available The frequency spectrum performs one of the main characteristics of a process. The aim of the paper is to show the coherence between the process and its own spectrum and how the behaviour and properties of a process itself can be deduced from its spectrum. Processes are categorized and general principles of their spectra calculation and recognition are given. The main stress is put on power spectra of electric and optic signals, as they also perform a kind of processes. These spectra can be directly measured, observed and examined by means of spectral analyzers and they are very important characteristics which can not be omitted at transmission techniques in telecommunication technologies. Further, the paper also deals with non electric processes, mainly with processes and spectra at mass servicing and how these spectra can be utilised in praxis.

  10. A VLT VIMOS integral field spectroscopic study of perturbed blue compact galaxies: UM 420 and UM 462

    CERN Document Server

    James, B L; Barlow, M J

    2009-01-01

    We report on optical integral field spectroscopy of two unrelated blue compact galaxies mapped with the 13 x 13 arcsec^2 VIMOS integral field unit at a resolution of 0.33 x 0.33 arcsec^2. Continuum and background subtracted emission line maps in the light of [O III] 5007, H-alpha, and [N II] 6584 are presented. Both galaxies display signs of ongoing perturbation and/or interaction. UM 420 is resolved for the first time to be a merging system composed of two starbursting components with an 'arm-like' structure associated with the largest component. UM 462 which is a disrupted system of irregular morphology is resolved into at least four starbursting regions. Maps of the H-alpha radial velocity and FWHM are discussed. No underlying broad line region was detected from either galaxy as the emission lines are well-fitted with single Gaussian profiles only. Electron temperatures and densities as well as the abundances of helium, oxygen, nitrogen, and sulphur were computed from spectra integrated over the whole gala...

  11. First light of the VLT planet finder SPHERE. III. New spectrophotometry and astrometry of the HR8799 exoplanetary system

    CERN Document Server

    Zurlo, A; Galicher, R; Maire, A -L; Mesa, D; Gratton, R; Chauvin, G; Kasper, M; Moutou, C; Bonnefoy, M; Desidera, S; Abe, L; Apai, D; Baruffolo, A; Baudoz, P; Baudrand, J; Beuzit, J -L; Blancard, P; Boccaletti, A; Cantalloube, F; Carle, M; Charton, J; Claudi, R U; Costille, A; de Caprio, V; Dohlen, K; Dominik, C; Fantinel, D; Feautrier, P; Feldt, M; Fusco, T; Gascone, E; Gigan, P; Girard, J H; Gissler, D; Gluck, L; Gry, C; Henning, T; Hugot, E; Janson, M; Jacquet, M; Lagrange, A -M; Langlois, M; Llored, M; Made, F; Magnard, Y; Martinez, P; Maurel, D; Mawet, D; Meyer, M R; Milli, J; Moeller-Nilsson, O; Mouillet, D; Origné, A; Pavlov, A; Petit, C; Puget, P; Quanz, S P; Rabou, P; Ramos, J; Roux, A; Salasnich, B; Salter, G; Sauvage, J -F; Schmid, H M; Soenke, C; Stadler, E; Suarez, M; Turatto, M; Udry, S; Vakili, F; Wahhaj, Z; Wildi, F

    2015-01-01

    The planetary system discovered around the young A-type HR8799 provides a unique laboratory to: a) test planet formation theories, b) probe the diversity of system architectures at these separations, and c) perform comparative (exo)planetology. We present and exploit new near-infrared images and integral-field spectra of the four gas giants surrounding HR8799 obtained with SPHERE, the new planet finder instrument at the Very Large Telescope, during the commissioning and science verification phase of the instrument (July-December 2014). With these new data, we contribute to completing the spectral energy distribution of these bodies in the 1.0-2.5 $\\mu$m range. We also provide new astrometric data, in particular for planet e, to further constrain the orbits. We used the infrared dual-band imager and spectrograph (IRDIS) subsystem to obtain pupil-stabilized, dual-band $H2H3$ (1.593 $\\mu$m, 1.667 $\\mu$m), $K1K2$ (2.110 $\\mu$m, 2.251 $\\mu$m), and broadband $J$ (1.245 $\\mu$m) images of the four planets. IRDIS was ...

  12. On the gas content of transitional disks: a VLT/X-Shooter study of accretion and winds

    CERN Document Server

    Manara, C F; Natta, A; Rosotti, G; Benisty, M; Ercolano, B; Ricci, L

    2014-01-01

    Transitional disks (TDs) are thought to be a late evolutionary stage of protoplanetary disks with dust depleted inner regions. The mechanism responsible for this depletion is still under debate. To constrain the models it is mandatory to have a good understanding of the properties of the gas content of the inner disk. Using X-Shooter broad band -UV to NIR- medium resolution spectroscopy we derive the stellar, accretion, and wind properties of a sample of 22 TDs. The analysis of these properties allows us to put strong constraints on the gas content in a region very close to the star (<0.2 AU) which is not accessible with any other observational technique. We fit the spectra with a self-consistent procedure to derive simultaneously SpT,Av,and mass accretion rates (Macc) of the targets. From forbidden emission lines we derive the wind properties of the targets. Comparing our findings to values for cTTs, we find that Macc and wind properties of 80% of the TDs in our sample, which is strongly biased towards st...

  13. Hydrogen permitted lines in the first near-IR spectra of Th 28 microjet: accretion or ejection tracers?

    CERN Document Server

    Coffey, Deirdre; Podio, Linda; Nisini, Brunella

    2010-01-01

    We report the first near-infrared detection of the bipolar microjet from TTauri star ThA 15-28 (aka Th 28). Spectra were obtained with VLT/ISAAC for the slit both perpendicular and parallel to the flow to examine jet kinematics and gas physics within the first arcsecond from the star. The jet was successfully detected in both molecular and atomic lines. The H_2 component was found to be entirely blueshifted around the base of the bipolar jet. It shows that only the blue lobe is emitting in H_2 while light is scattered in the direction of the red lobe, highlighting an asymmetric extinction and/or excitation between the two lobes. Consistent with this view, the red lobe is brighter in all atomic lines. Interestingly, the jet was detected not only in [Fe II], but also in Br gamma and Pa beta lines. Though considered tracers mainly of accretion, we find that these high excitation hydrogen permitted lines trace the jet as far as 150 AU from the star. This is confirmed in a number of ways: the presence of the [Fe I...

  14. Physical properties of galaxies and their evolution in the VIMOS VLT Deep Survey. I. The evolution of the mass-metallicity relation up to z~0.9

    CERN Document Server

    Lamareille, F; Contini, T; Walcher, C J; Charlot, S; Pérez-Montero, E; Zamorani, G; Pozzetti, L; Bolzonella, M; Garilli, B; Paltani, S; Bongiorno, A; Le Fèvre, O; Bottini, D; Le Brun, V; MacCagni, D; Scaramella, R; Scodeggio, M; Tresse, L; Vettolani, G; Zanichelli, A; Adami, C; Arnouts, S; Bardelli, S; Cappi, A; Ciliegi, P; Foucaud, S; Franzetti, P; Gavignaud, I; Guzzo, L; Ilbert, O; Iovino, A; McCracken, H J; Marano, B; Marinoni, C; Mazure, A; Meneux, B; Merighi, R; Pellò, R; Pollo, A; Radovich, M; Vergani, D; Zucca, E; Romano, A; Grado, A; Limatola, L

    2008-01-01

    We derive the mass-metallicity relation of star-forming galaxies up to $z\\sim0.9$, using data from the VIMOS VLT Deep Survey. Automatic measurement of emission-line fluxes and equivalent widths have been performed on the full spectroscopic sample. This sample is divided into two sub-samples depending on the apparent magnitude selection: wide ($I_{\\mathrm{AB}}<22.5$) and deep $I_{\\mathrm{AB}}<24$). These two samples span two different ranges of stellar masses. Emission-line galaxies have been separated into star-forming galaxies and active galactic nuclei using emission line ratios. For the star-forming galaxies the emission line ratios have also been used to estimate gas-phase oxygen abundance, using empirical calibrations renormalized in order to give consistent results at low and high redshifts. The stellar masses have been estimated by fitting the whole spectral energy distributions with a set of stellar population synthesis models. We assume at first order that the shape of the mass-metallicity rela...

  15. Mid-Infrared diagnostics of metal-rich HII regions from VLT and Spitzer Spectroscopy of Young Massive Stars in W31

    CERN Document Server

    Furness, JP; Morris, PW; Barbosa, CL; Blum, RD; Conti, PS; van Dyk, SD

    2009-01-01

    We present near-IR VLT/ISAAC and mid-IR Spitzer/IRS spectroscopy of the young massive cluster in the W31 star-forming region. H-band spectroscopy provides refined classifications for four cluster members O stars with respect to Blum et al. In addition, photospheric features are detected in the massive Young Stellar Object (mYSO) #26. Spectroscopy permits estimates of stellar temperatures and masses, from which a cluster age of ~0.6 Myr and distance of 3.3 kpc are obtained, in excellent agreement with Blum et al. IRS spectroscopy reveals mid-infrared fine structure line fluxes of [Ne II-III] and [S III-IV] for four O stars and five mYSOs. In common with previous studies, stellar temperatures of individual stars are severely underestimated from the observed ratios of fine-structure lines, despite the use of contemporary stellar atmosphere and photoionization models. We construct empirical temperature calibrations based upon the W31 cluster stars of known spectral type, supplemented by two inner Milky Way ultrac...

  16. Calibration of quasi-static aberrations in exoplanet direct-imaging instruments with a Zernike phase-mask sensor. II. Concept validation with ZELDA on VLT/SPHERE

    CERN Document Server

    N'Diaye, M; Dohlen, K; Sauvage, J -F; Caillat, A; Costille, A; Girard, J H V; Beuzit, J -L; Fusco, T; Blanchard, P; Merrer, J Le; Mignant, D Le; Madec, F; Moreaux, G; Mouillet, D; Puget, P; Zins, G

    2016-01-01

    Warm or massive gas giant planets, brown dwarfs, and debris disks around nearby stars are now routinely observed by dedicated high-contrast imaging instruments on large, ground-based observatories. These facilities include extreme adaptive optics (ExAO) and state-of-the-art coronagraphy to achieve unprecedented sensitivities for exoplanet detection and spectral characterization. However, differential aberrations between the ExAO sensing path and the science path represent a critical limitation for the detection of giant planets with a contrast lower than a few $10^{-6}$ at very small separations (<0.3\\as) from their host star. In our previous work, we proposed a wavefront sensor based on Zernike phase contrast methods to circumvent this issue and measure these quasi-static aberrations at a nanometric level. We present the design, manufacturing and testing of ZELDA, a prototype that was installed on VLT/SPHERE during its reintegration in Chile. Using the internal light source of the instrument, we performed...

  17. Deep imaging survey of the environment of Alpha Centauri - I. Adaptive optics imaging of Alpha Cen B with VLT-NACO

    CERN Document Server

    Kervella, P; Foresto, V C D; Kervella, Pierre; Th\\'{e}venin, Fr\\'{e}d\\'{e}ric; Foresto, Vincent Coud\\'{e} Du

    2006-01-01

    Context: Alpha Centauri is our closest stellar neighbor, at a distance of only 1.3 pc, and its two main components have spectral types comparable to the Sun. This is therefore a favorable target for an imaging search for extrasolar planets. Moreover, indications exist that the gravitational mass of Alpha Cen B is higher than its modeled mass, the difference being consistent with a substellar companion of a few tens of Jupiter masses. Aims: We searched for faint comoving companions to Alpha Cen B. As a secondary objective, we built a catalogue of the detected background sources. Methods: We used the NACO adaptive optics system of the VLT in the J, H, and Ks bands to search for companions to Alpha Cen B. This instrument allowed us to achieve a very high sensitivity to point-like sources, with a limiting magnitude of m\\_Ks ~ 18 at 7" from the star. We complemented this data set with archival coronagraphic images from the HST-ACS instrument to obtain an accurate astrometric calibration. Results: Over the observed...

  18. First light of the VLT planet finder SPHERE. I. Detection and characterization of the sub-stellar companion GJ 758 B

    CERN Document Server

    Vigan, A; Ginski, C; Beust, H; Galicher, R; Janson, M; Baudino, J -L; Buenzli, E; Hagelberg, J; D'Orazi, V; Desidera, S; Maire, A -L; Gratton, R; Sauvage, J -F; Chauvin, G; Thalmann, C; Malo, L; Salter, G; Zurlo, A; Antichi, J; Baruffolo, A; Baudoz, P; Blanchard, P; Boccaletti, A; Beuzit, J -L; Carle, M; Claudi, R; Costille, A; Delboulbé, A; Dohlen, K; Dominik, C; Feldt, M; Fusco, T; Gluck, L; Girard, J; Giro, E; Gry, C; Henning, T; Hubin, N; Hugot, E; Jacquet, M; Kasper, M; Lagrange, A -M; Langlois, M; Mignant, D Le; Llored, M; Madec, F; Martinez, P; Mawet, D; Mesa, D; Milli, J; Mouillet, D; Moulin, T; Moutou, C; Origné, A; Pavlov, A; Perret, D; Petit, C; Pragt, J; Puget, P; Rabou, P; Rochat, S; Roelfsema, R; Salasnich, B; Schmid, H -M; Sevin, A; Smette, A; Stadler, E; Suarez, M; Turatto, M; Udry, S; Vakili, F; Wahhaj, Z; Weber, L; Wildi, F

    2015-01-01

    GJ758 B is a brown dwarf companion to a nearby (15.76 pc) solar-type, metal-rich (M/H = +0.2 dex) main-sequence star (G9V) that was discovered with Subaru/HiCIAO in 2009. From previous studies, it has drawn attention as being the coldest (~600K) companion ever directly imaged around a neighboring star. We present new high-contrast data obtained during the commissioning of the SPHERE instrument at the VLT. The data was obtained in Y-, J-, H-, and Ks-bands with the dual-band imaging (DBI) mode of IRDIS, providing a broad coverage of the full near-infrared (near-IR) range at higher contrast and better spectral sampling than previously reported. In this new set of high-quality data, we report the re-detection of the companion, as well as the first detection of a new candidate closer-in to the star. We use the new 8 photometric points for an extended comparison of GJ758 B with empirical objects and 4 families of atmospheric models. From comparison to empirical object, we estimate a T8 spectral type, but none of th...

  19. Discovery of concentric broken rings at sub-arcsec separations in the HD 141569A gas-rich, debris disk with VLT/SPHERE

    CERN Document Server

    Perrot, C; Pantin, E; Augereau, J-C; Lagrange, A-M; Galicher, R; Maire, A-L; Mazoyer, J; Milli, J; Rousset, G; Gratton, R; Bonnefoy, M; Brandner, W; Buenzli, E; Langlois, M; Lannier, J; Mesa, D; Peretti, S; Salter, G; Sissa, E; Chauvin, G; Desidera, S; Feldt, M; Vigan, A; Di Folco, E; Dutrey, A; Péricaud, J; Baudoz, P; Benisty, M; De Boer, J; Garufi, A; Girard, J H; Menard, F; Olofsson, J; Quanz, S P; Mouillet, D; Christiaens, V; Casassus, S; Beuzit, J -L; Blanchard, P; Carle, M; Fusco, T; Giro, E; Hubin, N; Maurel, D; Moeller-Nilsson, O; Sevin, A; Weber, L

    2016-01-01

    Transition disks correspond to a short stage between the young protoplanetary phase and older debris phase. Along this evolutionary sequence, the gas component disappears leaving room for a dust-dominated environment where already-formed planets signpost their gravitational perturbations. We endeavor to study the very inner region of the well-known and complex debris, but still gas-rich disk, around HD 141569A using the exquisite high-contrast capability of SPHERE at the VLT. Recent near-infrared (IR) images suggest a relatively depleted cavity within ~200 au, while former mid-IR data indicate the presence of dust at separations shorter than ~100 au. We obtained multi-wavelength images in the near-IR in J, H2, H3 and Ks bands with the IRDIS camera and a 0.95-1.35 micrometers spectral data cube with the IFS. Data were acquired in pupil-tracking mode, thus allowing for angular differential imaging. We discovered several new structures inside 1", of which the most prominent is a bright ring with sharp edges (sem...

  20. High-contrast imaging of Sirius~A with VLT/SPHERE: Looking for giant planets down to one astronomical unit

    CERN Document Server

    Vigan, A; Salter, G; Mesa, D; Homeier, D; Moutou, C; Allard, F

    2015-01-01

    Sirius has always attracted a lot of scientific interest, especially after the discovery of a companion white dwarf at the end of the 19th century. Very early on, the existence of a potential third body was put forward to explain some of the observed properties of the system. We present new coronagraphic observations obtained with VLT/SPHERE that explore, for the very first time, the innermost regions of the system down to 0.2" (0.5 AU) from Sirius A. Our observations cover the near-infrared from 0.95 to 2.3 $\\mu$m and they offer the best on-sky contrast ever reached at these angular separations. After detailing the steps of our SPHERE/IRDIFS data analysis, we present a robust method to derive detection limits for multi-spectral data from high-contrast imagers and spectrographs. In terms of raw performance, we report contrasts of 14.3 mag at 0.2", ~16.3 mag in the 0.4-1.0" range and down to 19 mag at 3.7". In physical units, our observations are sensitive to giant planets down to 11 $M_{Jup}$ at 0.5 AU, 6-7 $...