350 Micron Observations of Ultraluminous Infrared Galaxies at Intermediate Redshifts

We present 350micron observations of 36 ultraluminous infrared galaxies (ULIRGs) at intermediate redshifts (0.089 <= z <= 0.926) using the Submillimeter High Angular Resolution Camera II (SHARC-II) on the Caltech Submillimeter Observatory (CSO). In total, 28 sources are detected at S/N >= 3, providing the first flux measurements longward of 100micron for a statistically significant sample of ULIRGs in the redshift range of 0.1 < z < 1.0. Combining our 350micron flux measurements with the existing IRAS 60 and 100micron data, we fit a single-temperature model to the spectral energy distribution (SED), and thereby estimate dust temperatures and far-IR luminosities. Assuming an emissivity index of beta = 1.5, we find a median dust temperature and far-IR luminosity of Td = 42.8+-7.1K and log(Lfir/Lsolar) = 12.2+-0.5, respectively. The far-IR/radio correlation observed in local star-forming galaxies is found to hold for ULIRGs in the redshift range 0.1 < z < 0.5, suggesting that the dust in these sources is predominantly heated by starbursts. We compare the far-IR luminosities and dust temperatures derived for dusty galaxy samples at low and high redshifts with our sample of ULIRGs at intermediate redshift. A general Lfir-Td relation is observed, albeit with significant scatter, due to differing selection effects and variations in dust mass and grain properties. The relatively high dust temperatures observed for our sample compared to that of high-z submillimeter-selected starbursts with similar far-IR luminosities suggest that the dominant star formation in ULIRGs at moderate redshifts takes place on smaller spatial scales than at higher redshifts.Comment: (24 pages in preprint format, 1 table, 7 figures, accepted for publication in ApJ

The application of GIS based decision-tree models for generating the spatial distribution of hydromorphic organic landscapes in relation to digital terrain data

Accurate information about organic/mineral soil occurrence is a prerequisite for many land resources management applications (including climate change mitigation). This paper aims at investigating the potential of using geomorphometrical analysis and decision tree modeling to predict the geographic distribution of hydromorphic organic landscapes in unsampled area in Denmark. Nine primary (elevation, slope angle, slope aspect, plan curvature, profile curvature, tangent curvature, flow direction, flow accumulation, and specific catchment area) and one secondary (steady-state topographic wetness index) topographic parameters were generated from Digital Elevation Models (DEMs) acquired using airborne LIDAR (Light Detection and Ranging) systems. They were used along with existing digital data collected from other sources (soil type, geological substrate and landscape type) to explain organic/mineral field measurements in hydromorphic landscapes of the Danish area chosen. A large number of tree-based classification models (186) were developed using (1) all of the parameters, (2) the primary DEM-derived topographic (morphological/hydrological) parameters only, (3) selected pairs of parameters and (4) excluding each parameter one at a time from the potential pool of predictor parameters. The best classification tree model (with the lowest misclassification error and the smallest number of terminal nodes and predictor parameters) combined the steady-state topographic wetness index and soil type, and explained 68% of the variability in organic/mineral field measurements. The overall accuracy of the predictive organic/inorganic landscapes' map produced (at 1:50 000 cartographic scale) using the best tree was estimated to be ca. 75%. The proposed classification-tree model is relatively simple, quick, realistic and practical, and it can be applied to other areas, thereby providing a tool to facilitate the implementation of pedological/hydrological plans for conservation and sustainable management. It is particularly useful when information about soil properties from conventional field surveys is limited

Determining the optimal length of regulatory guarantee: A Length-of-Contract Auction

One of the biggest challenges in the area of infrastructure investment is the provision of funding to finance activities. This paper presents an auction design which can reduce the financing cost of infrastructure investments by allowing the length of the regulatory funding period to be determined via an auction. The auction allows bidders to submit bids against a payment for periods of varying length. Thus instead of, for example, a fixed 20-year contract period, some bidders might want to bid for financing over a longer period, say 25 or 30 years. This can be desirable in terms of securing more favourable terms in the financial markets. Our auction design can secure efficiency and lower financing costs. Our auction is motivated by the auctions currently being undertaken by the UK energy regulator (Ofgem) for financing offshore transmission assets. Although the auction was designed with electricity transmission in mind, the auction could be used in other areas of infrastructure investment

The Strategic Robustness of Mark-up Equilibria

This paper is an extension of the paper 'The Robustness of Agent-Based Models of Electricity Wholesale Markets', EPRG1213 which was motivated by the problem of analysing market power in liberalised electricity markets. That paper examined two particular forms of agent-based models commonly used in electricity market modelling, and showed that while these mark-up equilibria are robust against Nash deviations. This paper extends the earlier results to explain why these equilibria are robust to single firm Nash Cournot deviations but shows they are vulnerable to more sophisticated deviations

Designing electiricty transmission auctions: an introduction to the relevant literature

The UK has ambitious plans for exploiting offshore wind for electricity production in order to meet its challenging target under the EU Renewable Energy Directive. This could involve investing up to £20bn in transmission assets to bring electricity ashore. An investment of this magnitude calls for an efficient mechanism to determine which projects get financed and ensuring that only those projects that are selected can be delivered at least costs to consumers. The electricity regulator’s ongoing tender auctions are likely to work well for point-to-point transmission and for networks already built. However, it is still unclear what kinds of models could be considered for complex meshed offshore (and onshore) networks where licences are granted not only to own and operate, but also to build a transmission network. This paper provides an extensive survey on the current theory and experience of auctions. The main objective is to discuss the design of auctions for transmission assets in which bidding for packages of transmission assets is a possibility

Determining the optimal length of regulatory guarantee: A Length-of-Contract Auction

One of the biggest challenges in the area of infrastructure investment is the provision of funding to finance activities. This paper presents an auction design which can reduce the financing cost of infrastructure investments by allowing the length of the regulatory funding period to be determined via an auction. The auction allows bidders to submit bids against a payment for periods of varying length. Thus instead of, for example, a fixed 20-year contract period, some bidders might want to bid for financing over a longer period, say 25 or 30 years. This can be desirable in terms of securing more favourable terms in the financial markets. Our auction design can secure efficiency and lower financing costs. Our auction is motivated by the auctions currently being undertaken by the UK energy regulator (Ofgem) for financing offshore transmission assets. Although the auction was designed with electricity transmission in mind, the auction could be used in other areas of infrastructure investment

Advanced detectors and signal processing

Continued progress is reported toward development of a silicon on garnet technology which would allow fabrication of advanced detection and signal processing circuits on bubble memories. The first integrated detectors and propagation patterns have been designed and incorporated on a new mask set. In addition, annealing studies on spacer layers are performed. Based on those studies, a new double layer spacer is proposed which should reduce contamination of the silicon originating in the substrate. Finally, the magnetic sensitivity of uncontaminated detectors from the last lot of wafers is measured. The measured sensitivity is lower than anticipated but still higher than present magnetoresistive detectors