1,779 research outputs found

    Lutte contre les cercosporioses du bananier aux Antilles françaises Banatrace, un système d'information géographique multi-acteurs pour la gestion et la traçabilité des épandages aériens

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    [Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]INSPIREBanatrace est un système d'information intégrant les tâches de gestion des épandages aériens qui incombent aux opérateurs dans le cadre de la lutte contre la cercosporiose de la banane en Guadeloupe et en Martinique. Cet outil multi-acteurs est l'aboutissement d'un travail d'analyse-conception réalisé par le Cemagref. En combinant une base de données répartie et des fonctions d'information géographique, il répond aux différents besoins de traçabilité imposée par la réglementation récente sur les épandages aériens. Il assure l'interface entre le gestionnaire, les opérateurs aériens, les planteurs, les groupements de producteurs, et l'administration. Au-delà de l'efficacité obtenue dans les taches de gestion, il contribue à améliorer la sécurité des personnes et la protection des cours d'eau et de l'environnement. / " Banatrace " is an information system integrating the European rules and regulations relative to the aerial spraying of pesticide over the banana plantations. It helps to the fight against the cercosporia contamination in the French West Indies. This tool aims to fulfill the information needed by the different parties involved in this process: user manager, planters, aerial treatment companies, planters' cooperatives and administration. It includes DBMS and GIS functionalities in order to program the treatments and to record all events, leading to a better traceability. Moreover carrying out treatment management, it contributes to improve people security and environment protection

    The size-star formation relation of massive galaxies at 1.5<z<2.5

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    We study the relation between size and star formation activity in a complete sample of 225 massive (M > 5 x 10^10 Msun) galaxies at 1.5<z<2.5, selected from the FIREWORKS UV-IR catalog of the CDFS. Based on stellar population synthesis model fits to the observed restframe UV-NIR SEDs, and independent MIPS 24 micron observations, 65% of galaxies are actively forming stars, while 35% are quiescent. Using sizes derived from 2D surface brightness profile fits to high resolution (FWHM_{PSF}~0.45 arcsec) groundbased ISAAC data, we confirm and improve the significance of the relation between star formation activity and compactness found in previous studies, using a large, complete mass-limited sample. At z~2, massive quiescent galaxies are significantly smaller than massive star forming galaxies, and a median factor of 0.34+/-0.02 smaller than galaxies of similar mass in the local universe. 13% of the quiescent galaxies are unresolved in the ISAAC data, corresponding to sizes <1 kpc, more than 5 times smaller than galaxies of similar mass locally. The quiescent galaxies span a Kormendy relation which, compared to the relation for local early types, is shifted to smaller sizes and brighter surface brightnesses and is incompatible with passive evolution. The progenitors of the quiescent galaxies, were likely dominated by highly concentrated, intense nuclear star bursts at z~3-4, in contrast to star forming galaxies at z~2 which are extended and dominated by distributed star formation.Comment: 6 pages, 4 figures, accepted for publication in Ap

    First Frontier Field Constraints on the Cosmic Star-Formation Rate Density at z~10 - The Impact of Lensing Shear on Completeness of High-Redshift Galaxy Samples

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    We search the complete Hubble Frontier Field dataset of Abell 2744 and its parallel field for z~10 sources to further refine the evolution of the cosmic star-formation rate density (SFRD) at z>8. We independently confirm two images of the recently discovered triply-imaged z~9.8 source by Zitrin et al. (2014) and set an upper limit for similar z~10 galaxies with red colors of J_125-H_160>1.2 in the parallel field of Abell 2744. We utilize extensive simulations to derive the effective selection volume of Lyman-break galaxies at z~10, both in the lensed cluster field and in the adjacent parallel field. Particular care is taken to include position-dependent lensing shear to accurately account for the expected sizes and morphologies of highly-magnified sources. We show that both source blending and shear reduce the completeness at a given observed magnitude in the cluster, particularly near the critical curves. These effects have a significant, but largely overlooked, impact on the detectability of high-redshift sources behind clusters, and substantially reduce the expected number of highly-magnified sources. The detections and limits from both pointings result in a SFRD which is higher by 0.4+-0.4 dex than previous estimates at z~10 from blank fields. Nevertheless, the combination of these new results with all other estimates remain consistent with a rapidly declining SFRD in the 170 Myr from z~8 to z~10 as predicted by cosmological simulations and dark-matter halo evolution in LambdaCDM. Once biases introduced by magnification-dependent completeness are accounted for, the full six cluster and parallel Frontier Field program will be an extremely powerful new dataset to probe the evolution of the galaxy population at z>8 before the advent of the JWST.Comment: 10 pages, 7 figures, changed to match accepted version to appear in Ap

    High-precision Photometric Redshifts from Spitzer/IRAC: Extreme [3.6]-[4.5] Colors Identify Galaxies in the Redshift Range z~6.6-6.9

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    One of the most challenging aspects of studying galaxies in the z>~7 universe is the infrequent confirmation of their redshifts through spectroscopy, a phenomenon thought to occur from the increasing opacity of the intergalactic medium to Lya photons at z>6.5. The resulting redshift uncertainties inhibit the efficient search for [C II] in z~7 galaxies with sub-mm instruments such as ALMA, given their limited scan speed for faint lines. One means by which to improve the precision of the inferred redshifts is to exploit the potential impact of strong nebular emission lines on the colors of z~4-8 galaxies as observed by Spitzer/IRAC. At z~6.8, galaxies exhibit IRAC colors as blue as [3.6]-[4.5] ~-1, likely due to the contribution of [O III]+Hb to the 3.6 mum flux combined with the absence of line contamination in the 4.5 mum band. In this paper we explore the use of extremely blue [3.6]-[4.5] colors to identify galaxies in the narrow redshift window z~6.6-6.9. When combined with an I-dropout criterion, we demonstrate that we can plausibly select a relatively clean sample of z~6.8 galaxies. Through a systematic application of this selection technique to our catalogs from all five CANDELS fields, we identify 20 probable z~6.6-6.9 galaxies. We estimate that our criteria select the ~50% strongest line emitters at z~6.8 and from the IRAC colors we estimate a typical [O III]+Hb rest-frame equivalent width of 1085A for this sample. The small redshift uncertainties on our sample make it particularly well suited for follow-up studies with facilities such as ALMA.Comment: In submission to the Astrophysical Journal, updated in response to the referee report, 13 pages, 11 figures, 1 tabl

    Lyman-alpha Emission from a Luminous z=8.68 Galaxy: Implications for Galaxies as Tracers of Cosmic Reionization

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    We report the discovery of Lyman-alpha emission (Lyα\alpha) in the bright galaxy EGSY-2008532660 (hereafter EGSY8p7) using the MOSFIRE spectrograph at the Keck Observatory. First reported by Roberts-Borsani et al. (2015), it was selected for spectroscopic observations because of its photometric redshift (zphot=8.570.43+0.22z_{phot}=8.57^{+0.22}_{-0.43}), apparent brightness (H160=25.26±0.09_{160}=25.26\pm0.09) and red Spitzer/IRAC [3.6]-[4.5] color indicative of contamination by strong oxygen emission in the [4.5] band. With a total integration of \sim4.3 hours, our data reveal an emission line at \simeq11776 {\AA} which we argue is likely Lyα\alpha at a redshift zspec=8.6830.004+0.001z_{spec}=8.683^{+0.001}_{-0.004}, in good agreement with the photometric estimate. The line was detected independently on two nights using different slit orientations and its detection significance is 7.5σ\sim7.5\sigma. An overlapping skyline contributes significantly to the uncertainty on the total line flux although the significance of the detected line is robust to a variety of skyline-masking procedures. By direct addition and a Gaussian fit, we estimate a 95\% confidence range of 1.0--2.5×1017\times10^{-17} erg s1^{-1} cm2^{-2}, corresponding to a rest-frame equivalent width of 17--42 {\AA}. EGSY8p7 is the most distant galaxy confirmed spectroscopically to date, and the third luminous source in the EGS field beyond zphot7.5z_{phot}\gtrsim7.5 with detectable Lyα\alpha emission viewed at a time when the intergalactic medium is believed to be fairly neutral. Although the reionization process was probably patchy, we discuss whether luminous sources with prominent IRAC color excesses may harbor harder ionizing spectra than the dominant fainter population thereby creating earlier ionized bubbles. Further spectroscopic follow-up of such bright sources promises important insight into the early formation of galaxies.Comment: V3: ApJL accepted; 7 pages, 4 figures, 1 tabl

    Control dependence for extended finite state machines

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    Though there has been nearly three decades of work on program slicing, there has been comparatively little work on slicing for state machines. One of the primary challenges that currently presents a barrier to wider application of state machine slicing is the problem of determining control dependence. We survey existing related definitions, introducing a new definition that subsumes one and extends another. We illustrate that by using this new definition our slices respect Weiser slicing’s termination behaviour. We prove results that clarify the relationships between our definition and older ones, following this up with examples to motivate the need for these differences

    S-CANDELS: The Spitzer-Cosmic Assembly Near-Infrared Deep Extragalactic Survey. Survey Design, Photometry, and Deep IRAC Source Counts

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    The Spitzer-Cosmic Assembly Deep Near-Infrared Extragalactic Legacy Survey (S-CANDELS; PI G. Fazio) is a Cycle 8 Exploration Program designed to detect galaxies at very high redshifts (z > 5). To mitigate the effects of cosmic variance and also to take advantage of deep coextensive coverage in multiple bands by the Hubble Space Telescope Multi-Cycle Treasury Program CANDELS, S-CANDELS was carried out within five widely separated extragalactic fields: the UKIDSS Ultra-Deep Survey, the Extended Chandra Deep Field South, COSMOS, the HST Deep Field North, and the Extended Groth Strip. S-CANDELS builds upon the existing coverage of these fields from the Spitzer Extended Deep Survey (SEDS) by increasing the integration time from 12 hours to a total of 50 hours but within a smaller area, 0.16 square degrees. The additional depth significantly increases the survey completeness at faint magnitudes. This paper describes the S-CANDELS survey design, processing, and publicly-available data products. We present IRAC dual-band 3.6+4.5 micron catalogs reaching to a depth of 26.5 AB mag. Deep IRAC counts for the roughly 135,000 galaxies detected by S-CANDELS are consistent with models based on known galaxy populations. The increase in depth beyond earlier Spitzer/IRAC surveys does not reveal a significant additional contribution from discrete sources to the diffuse Cosmic Infrared Background (CIB). Thus it remains true that only roughly half of the estimated CIB flux from COBE/DIRBE is resolved.Comment: 23 pages, 19 figures, accepted by ApJ

    A Public Ks-selected Catalog in the COSMOS/UltraVISTA Field: Photometry, Photometric Redshifts and Stellar Population Parameters

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    We present a catalog covering 1.62 deg^2 of the COSMOS/UltraVISTA field with PSF-matched photometry in 30 photometric bands. The catalog covers the wavelength range 0.15um - 24um including the available GALEX, Subaru, CFHT, VISTA and Spitzer data. Catalog sources have been selected from the DR1 UltraVISTA Ks band imaging that reaches a depth of K_{s,tot} = 23.4 AB (90% completeness). The PSF-matched catalog is generated using position-dependent PSFs ensuring accurate colors across the entire field. Also included is a catalog of photometric redshifts (z_phot) for all galaxies computed with the EAZY code. Comparison with spectroscopy from the zCOSMOS 10k bright sample shows that up to z ~ 1.5 the z_phot are accurate to dz/(1 + z) = 0.013, with a catastrophic outlier fraction of only 1.6%. The z_phot also show good agreement with the z_phot from the NEWFIRM Medium Band Survey (NMBS) out to z ~ 3. A catalog of stellar masses and stellar population parameters for galaxies determined using the FAST spectral energy distribution fitting code is provided for all galaxies. Also included are rest-frame U-V and V-J colors, L_2800 and L_IR. The UVJ color-color diagram confirms that the galaxy bi-modality is well-established out to z ~ 2. Star-forming galaxies also obey a star forming "main sequence" out to z ~ 2.5, and this sequence evolves in a manner consistent with previous measurements. The COSMOS/UltraVISTA Ks-selected catalog covers a unique parameter space in both depth, area, and multi-wavelength coverage and promises to be a useful tool for studying the growth of the galaxy population out to z ~ 3 - 4.Comment: 20 pages, 14 figures. Accepted to the ApJSS. Catalog data products available for download here: http://www.strw.leidenuniv.nl/galaxyevolution/ULTRAVISTA
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