The Mid-Infrared Instrument for the James Webb Space Telescope, V: Predicted Performance of the MIRI Coronagraphs

The imaging channel on the Mid-Infrared Instrument (MIRI) is equipped with four coronagraphs that provide high contrast imaging capabilities for studying faint point sources and extended emission that would otherwise be overwhelmed by a bright point-source in its vicinity. Such bright sources might include stars that are orbited by exoplanets and circumstellar material, mass-loss envelopes around post-main-sequence stars, the near-nuclear environments in active galaxies, and the host galaxies of distant quasars. This paper describes the coronagraphic observing modes of MIRI, as well as performance estimates based on measurements of the MIRI flight model during cryo-vacuum testing. A brief outline of coronagraphic operations is also provided. Finally, simulated MIRI coronagraphic observations of a few astronomical targets are presented for illustration

Remote-sensing Characterisation of Major Solar System Bodies with the Twinkle Space Telescope

Remote-sensing observations of Solar System objects with a space telescope offer a key method of understanding celestial bodies and contributing to planetary formation and evolution theories. The capabilities of Twinkle, a space telescope in a low Earth orbit with a 0.45m mirror, to acquire spectroscopic data of Solar System targets in the visible and infrared are assessed. Twinkle is a general observatory that provides on demand observations of a wide variety of targets within wavelength ranges that are currently not accessible using other space telescopes or that are accessible only to oversubscribed observatories in the short-term future. We determine the periods for which numerous Solar System objects could be observed and find that Solar System objects are regularly observable. The photon flux of major bodies is determined for comparison to the sensitivity and saturation limits of Twinkle's instrumentation and we find that the satellite's capability varies across the three spectral bands (0.4-1, 1.3-2.42, and 2.42-4.5{\mu}m). We find that for a number of targets, including the outer planets, their large moons, and bright asteroids, the model created predicts that with short exposure times, high-resolution spectra (R~250, {\lambda} 2.42{\mu}m) could be obtained with signal-to-noise ratio (SNR) of >100 with exposure times of <300s

The CEECs as FDI attractors: are they a menace to the EU periphery?

The change of economic, social and political orientation in Central and Eastern European countries (CEEC), together with their expressed intention of joining the European Union (EU) in a foreseeable future, have raised a number of challenging questions. One object of interest has been the implications of Eastern openness in terms of international capital reallocation. This paper concentrates on the issue of foreign direct investment (FDI), which is considered a major channel of economic integration. In fact, in the particular case of these countries, a dramatic change in the pattern of FDI inflows took place in recent years. A number of studies have surveyed the determinants of FDI to this region but the issue still remains relatively unexplored from the empirical point of view. Using a random effects panel data model in the analysis, we try to empirically uncover the main determinants of FDI and to examine the probability of FDI diversion from the EU periphery to these transition economies. This issue is especially interesting for the EU periphery in general, and for cheap labour suppliers such as Portugal in particular, since there are reasons to believe that ‘the east may be getting what would otherwise come south’

Supernova / Acceleration Probe: A Satellite Experiment to Study the Nature of the Dark Energy

The Supernova / Acceleration Probe (SNAP) is a proposed space-based experiment designed to study the dark energy and alternative explanations of the acceleration of the Universe's expansion by performing a series of complementary systematics-controlled measurements. We describe a self-consistent reference mission design for building a Type Ia supernova Hubble diagram and for performing a wide-area weak gravitational lensing study. A 2-m wide-field telescope feeds a focal plane consisting of a 0.7 square-degree imager tiled with equal areas of optical CCDs and near infrared sensors, and a high-efficiency low-resolution integral field spectrograph. The SNAP mission will obtain high-signal-to-noise calibrated light-curves and spectra for several thousand supernovae at redshifts between z=0.1 and 1.7. A wide-field survey covering one thousand square degrees resolves ~100 galaxies per square arcminute. If we assume we live in a cosmological-constant-dominated Universe, the matter density, dark energy density, and flatness of space can all be measured with SNAP supernova and weak-lensing measurements to a systematics-limited accuracy of 1%. For a flat universe, the density-to-pressure ratio of dark energy can be similarly measured to 5% for the present value w0 and ~0.1 for the time variation w'. The large survey area, depth, spatial resolution, time-sampling, and nine-band optical to NIR photometry will support additional independent and/or complementary dark-energy measurement approaches as well as a broad range of auxiliary science programs. (Abridged)Comment: 40 pages, 18 figures, submitted to PASP, http://snap.lbl.go

Opportunities for maser studies with the Square Kilometre Array

The Square Kilometre Array (SKA) is the radio telescope of the next generation, providing an increase in sensitivity and angular resolution of two orders of magnitude over existing telescopes. Currently, the SKA is expected to span the frequency range 0.1-25 GHz with capabilities including a wide field-of-view and measurement of polarised emission. Such a telescope has enormous potential for testing fundamental physical laws and producing transformational discoveries. Important science goals include using H2O megamasers to make precise estimates of H0, which will anchor the extragalactic distance scale, and to probe the central structures of accretion disks around supermassive black holes in AGNs, to study OH megamasers associated with extreme starburst activity in distant galaxies and to study with unprecedented precision molecular gas and star formation in our Galaxy.Comment: 5 pages, to appear in: IAU Symposium 242 Astrophysical Masers and their Environment

Inventors and the Geographical Breadth of Knowledge Soillovers

This paper studies the geographical breadth of knowledge spillovers. Previous research suggests that knowledge spillovers benefit from geographical proximity in technologically active and rich regions more than elsewhere. An alternative view explains the geographical breadth of knowledge spillovers as a function of the characteristics and personal networks of the individuals. We test these two competing theories by using information provided directly by the inventors of 6,750 European patents (PatVal-EU survey). Our results confirm the importance of inventors’ personal background. However, compared to previous research, we find that the level of education of the inventors is key in shaping the geographical breadth of knowledge spillovers. Highly educated inventors rely more on geographically wide research networks than their less educated peers. This holds after controlling for the mobility of the inventors and for the scientific nature of the research performed. Differently, location matters only in the very rare regions in Europe that perform the bulk of the research in the specific discipline of the inventors.

Bridging the gap? Corruption, knowledge and foreign ownership

We argue that in addition to host corruption per se, as accounted for by the existing literature, an explanation of inter-country variation in FDI needs to account for the distance between the host and home corruption, which we call relative corruption. We use a large matched home-host firm-level panel data-set for 1998-2006 from CEE transition countries. Year-specific selectivity corrected estimates suggest that, ceteris paribus, higher relative ‘grand’ corruption lowers foreign ownership as the returns to investment tends to be lower in more corrupt environment. However, after controlling for the selectivity bias, knowledge-intensive parent firms are found to hold controlling ownership, as the difficulty of successful joint venture looms large in more corrupt environment. Results are robust to alternative specifications.Financial support from the ESRC under RES-062-23-0986 is acknowledge

Remittances and the brain drain

In most destination countries, immigration policies are increasingly tilted toward the most skilled individuals. Whether this shift hurts economic prospects in sending countries, as argued by the traditional brain drain literature, is somewhat controversial. The most recent literature has focused on the link between skilled out-migration and educational achievements. In this paper, we emphasize a different channel. It is often argued that skilled migrants raise economic welfare at home thanks to a relatively larger flow of remittances. Skilled migrants typically earn relatively more and, ceteris paribus, will therefore remit more. However, they are also likely to spend a longer span of time abroad and also are more likely to reunite with their close family in the host country. Both factors should be associated with a relatively smaller flow of remittances from skilled migrants. Hence, the sign of the impact of the brain drain on total remittances is an empirical question. We first develop a simple model showing that skilled migrants may have indeed a lower propensity to remit home out of a given flow of earnings abroad. We then derive an empirical equation of remittances and estimate it on a large panel of developing countries. As a measure of the brain drain, we use the dataset by Docquier and Marfouk (2004) that in turn builds on the pioneering work of Carrington and Detragiache (2004). We find considerable evidence that the brain drain is associated with a smaller flow of remittances.remittances, migration, brain drain