22 research outputs found
Supplement: "Localization and broadband follow-up of the gravitational-wave transient GW150914" (2016, ApJL, 826, L13)
This Supplement provides supporting material for Abbott et al. (2016a). We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the different bands
O fato social total brasileiro: uma perspectiva etnográfica sobre a recepção pública da copa do mundo no Brasil
EUREC⁴A
The science guiding the EUREC⁴A campaign and its measurements is presented. EUREC⁴A comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic – eastward and southeastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, EUREC⁴A marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or the life cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso- (200 km) and larger (500 km) scales, roughly 400 h of flight time by four heavily instrumented research aircraft; four global-class research vessels; an advanced ground-based cloud observatory; scores of autonomous observing platforms operating in the upper ocean (nearly 10 000 profiles), lower atmosphere (continuous profiling), and along the air–sea interface; a network of water stable isotopologue measurements; targeted tasking of satellite remote sensing; and modeling with a new generation of weather and climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that EUREC⁴A explored – from North Brazil Current rings to turbulence-induced clustering of cloud droplets and its influence on warm-rain formation – are presented along with an overview of EUREC⁴A's outreach activities, environmental impact, and guidelines for scientific practice. Track data for all platforms are standardized and accessible at https://doi.org/10.25326/165 (Stevens, 2021), and a film documenting the campaign is provided as a video supplement
EUREC⁴A
The science guiding the EUREC⁴A campaign and its measurements is presented. EUREC⁴A comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic – eastward and southeastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, EUREC⁴A marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or the life cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso- (200 km) and larger (500 km) scales, roughly 400 h of flight time by four heavily instrumented research aircraft; four global-class research vessels; an advanced ground-based cloud observatory; scores of autonomous observing platforms operating in the upper ocean (nearly 10 000 profiles), lower atmosphere (continuous profiling), and along the air–sea interface; a network of water stable isotopologue measurements; targeted tasking of satellite remote sensing; and modeling with a new generation of weather and climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that EUREC⁴A explored – from North Brazil Current rings to turbulence-induced clustering of cloud droplets and its influence on warm-rain formation – are presented along with an overview of EUREC⁴A's outreach activities, environmental impact, and guidelines for scientific practice. Track data for all platforms are standardized and accessible at https://doi.org/10.25326/165 (Stevens, 2021), and a film documenting the campaign is provided as a video supplement
Localization and Broadband Follow-up of the Gravitational-wave Transient GW150914
A gravitational-wave (GW) transient was identified in data recorded by
the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)
detectors on 2015 September 14. The event, initially designated G184098
and later given the name GW150914, is described in detail elsewhere. By
prior arrangement, preliminary estimates of the time, significance, and
sky location of the event were shared with 63 teams of observers
covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths
with ground- and space-based facilities. In this Letter we describe the
low-latency analysis of the GW data and present the sky localization of
the first observed compact binary merger. We summarize the follow-up
observations reported by 25 teams via private Gamma-ray Coordinates
Network circulars, giving an overview of the participating facilities,
the GW sky localization coverage, the timeline, and depth of the
observations. As this event turned out to be a binary black hole merger,
there is little expectation of a detectable electromagnetic (EM)
signature. Nevertheless, this first broadband campaign to search for a
counterpart of an Advanced LIGO source represents a milestone and
highlights the broad capabilities of the transient astronomy community
and the observing strategies that have been developed to pursue neutron
star binary merger events. Detailed investigations of the EM data and
results of the EM follow-up campaign are being disseminated in papers by
the individual teams.
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Localization and broadband follow-up of the gravitational-wave transient GW150914
A gravitational-wave transient was identified in data recorded by the Advanced LIGO detectors on 2015 September 14. The event candidate, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the gravitational wave data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network Circulars, giving an overview of the participating facilities, the gravitational wave sky localization coverage, the timeline and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the electromagnetic data and results of the electromagnetic follow-up campaign will be disseminated in the papers of the individual teams
Remarkable enhancement of the selective catalytic reduction of NO at low temperature by collaborative effect of ethanol and NH 3 over silver supported catalyst
International audienc
Influence of Sodium and/or Phosphorus Addition on the Deactivation of Cu-FER Zeolites for SCR of NOx with NH3
International audienceThis work investigates the effect of sodium and phosphorus on the DeNOx performances of model Cu-FER SCR catalysts with two copper loadings (2.8wt% and 6.1wt%). These inorganic elements, present in the Biodiesel fuels and lubricants, were added by wet-impregnation using two solvents: water or ethanol. Catalysts were evaluated in standard-SCR conditions as well as in NO and NH3 oxidation, and characterized by means of H2-TPR and NH3 adsorption monitored by FT-IR. It was evidenced that catalytic behaviors were highly influenced by the implemented impregnation route with a stronger impact of water as solvent. Whatever the studied catalysts, NH3 adsorption capacities decreased after addition of sodium and/or phosphorus. Interestingly, sodium and phosphorus acted differently on the poisoning of NH3 adsorption sites. Na mainly poisoned Brønsted acid sites and favored a back exchange with Cu 2+ species (especially when Na was added in water), while phosphorus directly interacted with copper species, mainly in exchange position. The deactivation observed at low temperature (250°C) was preferentially due to the decrease in NH3 adsorption together with the increase in the copper-phosphorus interaction, especially for copper species in exchange position
Biofuel Impact on Diesel Engine After-Treatment: Deactivation Mechanisms and Soot Reactivity
International audienc