23 research outputs found

    Sloan Digital Sky Survey IV: mapping the Milky Way, nearby galaxies, and the distant universe

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    We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median ). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July

    Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe

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    We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z0.03z\sim 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z0.6z\sim 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July

    Sloan Digital Sky Survey IV : mapping the Milky Way, nearby galaxies, and the distant universe

    Get PDF
    We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z ~ 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z ~ 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July

    Sloan Digital Sky Survey IV: mapping the Milky Way, nearby galaxies, and the distant universe

    Get PDF
    We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median ). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July

    Impact of changing meteorology and air pollution on forest ecosystems in Lithuania -strategies for adaptation to and mitigation of the main threats of global change

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    Global change in Lithuania is predicted to promote increasing air temperature across seasons, a decrease in snow cover and an increase in heavy rain events. Changes in atmospheric circulation reduce seasonal climatic amplitudes, but enhance air pollution presumably tropospheric ozone, acidification and biogenic volatile organic compounds (BVOC) which will impact on tree growth and ecosystem performance. To mitigate main threats of global change the objective of the recently established comprehensive survey in Lithuanian forests is to develop strategies for silvicultural management in order to prepare forest systems ensuring ecosystem services. Intensive investigations at selected forest sites combine growth and injury analysis with ecophysiological assessments of tree water consumption, stomatal regulation and stomatal uptake of ozone, and tree bound BVOC emissions. Combining such investigations with long-term monitoring on environmental pollution and regional peculiarities in Lithuania insight is gathered on tree growth in dependence of environmental stress. The combination of knowledge on tree growth, ecophysiolocal performance and methods of BSOA formation will provide a diagnostic tool for differential stress diagnosis and treatment measures under the specific requirements of LithuaniaFizinių ir technologijos mokslų centrasVytauto Didžiojo universitetasŽemės ūkio akademij

    The response of intra-annual stem circumference of prevailing in Lithuania tree species to meteorology and air pollution under different site condition

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    Global change in Lithuania is predicted to promote increasing air temperature across seasons, a decrease in snow cover and an increase in heavy rain as well as more frequent drought events. Changes in atmospheric circulation reduce seasonal climatic amplitudes, but enhance air pollution most presumably induced by ozone, acidification and UV radiation which in turn will affect tree growth and ecosystem performance in general. Intensive investigations at selected different humidity and nutrition regime forest sites combine seasonal growth of Scots pine, Norway spruce, and silver and downy birch trees analysis with ecophysiological assessments of tree water consumption under the presses of different environmental conditions. Significance of the effect of the hourly, daily and weekly data on intra-annual stem circumference was esteblished. We hypothesized that Scots pine is becoming a climax tree species under progressively declining soil water availability, while Norway spruce is more sensitive to short term drought events on water limited sites than pine and birch trees, whereas birch trees are more sensitive to short term drought events on eutrophic peat sites in Lithuania. The obtained data on intra-annual stem circumference revealed that coniferous tree species were more sensitive to environmental changes than broadleaf tree species like birch trees due to their lower transpiration rates. The study is based on the results obtained conducting national project supported by Lithuanian Council of Research "FOREstRESS" (SIT- 3/2015)Fizinių ir technologijos mokslų centrasVytauto Didžiojo universitetasŽemės ūkio akademij

    Comparative analyses of gas exchange characteristics and chlorophyll fluorescence of three dominant tree species during the vegetation season in hemi-boreal zone, Lithuania

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    Current climate scenarios predict rising air temperature along with increasing frequency and intensity of summer drought in the Central and Eastern Europe. Severe drought episodes affect physiological processes in trees such as transpiration, photosynthesis and carbon allocation. Understanding gas exchange between plants and the atmosphere is important in woody plant research. The aim of this study was to evaluate differences in gas exchange characteristics and chlorophyll fluorescence of tree species prevailing in Lithuania Scots pine, Norway spruce and Silver birch and their physiological response to water stress. The study was conducted in Aukstaitija integrated monitoring station, Lithuania. Gas exchange parameters and chlorophyll fluorescence were measured during the vegetation season of 2016. Meteorological parameters were obtained from the monitoring station. Four weather periods with different meteorological conditions were identified. Under moderate drought conditions all investigated tree species demonstrated reduced photosynthetic rates, lower stomatal conduction transpiration rates, water use efficiency and instantaneous carboxylation efficiency. During moderate drought, intercellular CO2 concentration of Norway spruce was higher and this species demonstrated the highest decrease in instantaneous carboxylation efficiency. No significant changes of maximal chlorophyll fluorescence Fv/Fm among species were detected during different weather periods except Silver birch. The investigated tree species reacted differently to weather conditions. The Scots pine demonstrated the highest tolerance to different weather conditions. The study confirmed the sensitivity of Norway spruce to drought conditions. The Silver birch was the least sensitive to temperature and humidity conditions variationFizinių ir technologijos mokslų centrasMiškų ir ekologijos fakultetasVytauto Didžiojo universiteta

    Characterization of aerosol mass spectra responses to temperature over a forest site in Lithuania

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    The chemical composition of submicron aerosol particles was characterized using an aerosol chemical speciation monitor (ACSM) at a mixed-mature forest site at the Aukštaitija Integrated Monitoring Station in the eastern part of Lithuania. Four organic aerosol (OA) factors were determined by positive matrix factorization (PMF) analysis applied for the ACSM data: semi-volatile oxygenated OA (SVOOA, the contribution to the total OA mass concentration was 33%), low-volatile oxygenated OA (LVOOA, 39%), cooking related OA (COA, 15%) and biomass burning OA (BBOA, 13%). In our study secondary organic aerosol (SOA) has been identified as one of the most important contributors to the submicron particle (PM1) mass concentration. A comparison between SVOOA and submicron forest organic aerosol mass (SFOM) was performed, and a good correlation of 0.75 between them was found. In our study the SOA concentration dependence on temperature was explored in 3 means: firstly, by investigating aerosol mass spectra measured during hot and cold days. It has been found that during hot days events signal intensities of m/z 42, 43, 45, 53 and 59 were about 2.1–2.7 times higher compared to those during cold days. Secondly, by investigating the temperature dependence of SVOOA and estimated SFOM. It has been found that SFOM and SVOOA concentrations increase with temperature. Thirdly, by assessing the influence of temperature related stomatal conduction on SVOOA concentration: no direct influence on SVOOA concentration was observedFizinių ir technologijos mokslų centrasMiškų ir ekologijos fakultetasVytauto Didžiojo universiteta
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