Impacts of climate change on storms and waves relevant to the coastal and marine environment around the UK

We have updated the review by Woolf and Wolf (2013) by summarising the results of the IPCC AR5 report for storms and waves and then including more-recent work published since 2013. There are similar conclusions: wavemodel results are controlled largely by the quality of the wind data used to drive them, and the forcing climate models have slightly improved in accuracy as well as resolution. In general, trends are obscured by wide natural variability and a low signal-to-noise ratio. Assessment of changes in storminess and waves over the last 200 years are limited by lack of data, while future projections are limited by the accuracy of climate models. Recent work has led to more insight in some areas. There are now more climate- and wave- model ensembles, more in-depth assessments of the results of CMIP5, and the CMIP6 project and IPCC AR6 assessments have started. There is a move towards higher-resolution models, which give better accuracy for simulation of tropical and extra-tropical storms. Further work is being done with coupled atmosphere-ocean-wave models, which give insight into key dynamic processes. There is evidence for an increase in North Atlantic storms at the end of the 20th Century. Some projections for North Atlantic storms over the 21st Century show an overall reduced frequency of storms and some indication of a poleward shift in the tracks, in the northern hemisphere (NH) winter, but there is substantial uncertainty in projecting changes in NH storm tracks, especially in the North Atlantic. Projections for waves in the North Atlantic show a reduction in mean wave height, but an increase in the most-severe wave heights. There is a likelihood of larger wave heights to the north of the UK as the Arctic sea ice retreats and leads to increased fetch

The Rise and Fall of Debris Disks: MIPS Observations of h and chi Persei and the Evolution of Mid-IR Emission from Planet Formation

We describe Spitzer/MIPS observations of the double cluster, h and $\chi$ Persei, covering a $\sim$ 0.6 square-degree area surrounding the cores of both clusters. The data are combined with IRAC and 2MASS data to investigate $\sim$ 616 sources from 1.25-24 $\mu m$. We use the long-baseline $K_{s}$-[24] color to identify two populations with IR excess indicative of circumstellar material: Be stars with 24 $\mu m$ excess from optically-thin free free emission and 17 fainter sources (J$\sim$ 14-15) with [24] excess consistent with a circumstellar disk. The frequency of IR excess for the fainter sources increases from 4.5 $\mu m$ through 24 $\mu m$. The IR excess is likely due to debris from the planet formation process. The wavelength-dependent behavior is consistent with an inside-out clearing of circumstellar disks. A comparison of the 24 $\mu m$ excess population in h and $\chi$ Per sources with results for other clusters shows that 24 $\mu m$ emission from debris disks 'rises' from 5 to 10 Myr, peaks at $\sim$ 10-15 Myr, and then 'falls' from $\sim$ 15/20 Myr to 1 Gyr.Comment: 48 pages, 15 figures, accepted for publication in The Astrophysical Journa

Controlled tuning of whispering gallery modes of GaN/InGaN microdisk cavities

Controlled tuning of the whispering gallery modes of GaN/InGaN {\mu}-disk cavities is demonstrated. The whispering gallery mode (WGM) tuning is achieved at room temperature by immersing the {\mu}-disks in water and irradiating with ultraviolet (UV) laser. The tuning rate can be controlled by varying the laser excitation power, with a nanometer precision accessible at low excitation power (~ several {\mu}W). The selective oxidation mechanism is proposed to explain the results and supported by theoretical analysis. The tuning of WGMs in GaN/InGaN {\mu}-disk cavities may have important implication in cavity quantum electrodynamics and the development of efficient light emitting devices

Development of the fast neutron imaging telescope

We report on the development of a next generation neutron telescope, with imaging and energy measurement capabilities, sensitive to neutrons in the 2-20 MeV energy range. The Fast Neutron Imaging Telescope (FNIT) was initially conceived to study solar neutrons as a candidate instrument for the Inner Heliosphere Sentinels (IHS) program under formulation at NASA. This detector is now being adapted to locate Special Nuclear Material (SNM) for homeland security purposes by detecting fission neutrons and reconstructing the image of their source. In either case, the detection principle is based on multiple elastic neutron-proton scatterings in organic scintillator. By reconstructing the scattering coordinates and measuring the recoil proton energy, the direction and energy of each neutron can be determined and discrete neutron sources identified. We describe the performance of the FNIT prototype, report on the current status of R&D efforts and present the results of recent laboratory measurements

The very nearby M/T dwarf binary SCR 1845-6357

The recently discovered star SCR 1845-6357 is the first late M/T dwarf binary discovered. SCR 1845 is a particular object due to its tight orbit (currently around 4 AU) and its proximity to the Sun (3.85 pc). We present spatially resolved VLT/NACO images and low resolution spectra of SCR 1845 in the J, H and K near-infrared bands. Since the T dwarf companion, SCR 1845B, is so close to the primary SCR 1845A, orbital motion is evident even within a year. Following the orbital motion, the binary's mass can be measured accurately within a decade, making SCR 1845B a key T-dwarf mass-luminosity calibrator. The NIR spectra allow for accurate determination of spectral type and also for rough estimates of the object's physical parameters. The spectral type of SCR 1845B is determined by direct comparison of the flux calibrated JHK spectra with T dwarf standard template spectra and also by NIR spectral indices obtained from synthetic photometry. Constrained values for surface gravity, effective temperature and metallicity are derived by comparison with model spectra. Our data prove that SCR 1845B is a brown dwarf of spectral type T6 that is co-moving with and therefore gravitationally bound to the M8.5 primary. Fitting the NIR spectrum of SCR 1845B to model spectra yields an effective temperature of about 950K and a surface gravity log(g)=5.1 (cgs) assuming solar metallicity. Mass and age of SCR 1845B are in the range 40 to 50 Jupiter masses and 1.8 to 3.1 Gyr.Comment: 5 pages, 4 figures, accepted for publication in Astronomy & Astrophysic

The MultiSite Spectroscopic Telescope campaign: 2m spectroscopy of the V361 Hya variable PG1605+072

We present results and analysis for the 2m spectroscopic part of the MultiSite Spectroscopic Telescope (MSST) campaign undertaken in May/June 2002. The goal of the project was to observe the pulsating subdwarf B star PG1605+072 simultaneously in velocity and photometry and to resolve as many of the >50 known modes as possible, which will allow a detailed asteroseismological analysis. We have obtained over 150 hours of spectroscopy, leading to an unprecedented noise level of only 207m/s. We report here the detection of 20 frequencies in velocity, with two more likely just below our detection threshold. In particular, we detect 6 linear combinations, making PG1605+072 only the second star known to show such frequencies in velocity. We investigate the phases of these combinations and their parent modes and find relationships between them that cannot be easily understood based on current theory. These observations, when combined with our simultaneous photometry, should allow asteroseismology of this most complicated of sdB pulsators.Comment: 9 pages, 5 figures, accepted for publication in A&A; Figure 1 at lower resolution than accepted versio

A full free spectral range tuning of p-i-n doped Gallium Nitride microdisk cavity

Effective, permanent tuning of the whispering gallery modes (WGMs) of p-i-n doped GaN microdisk cavity with embedded InGaN quantum dots over one free spectral range is successfully demonstrated by irradiating the microdisks with a ultraviolet laser (380nm) in DI water. For incident laser powers between 150 and 960 nW, the tuning rate varies linearly. Etching of the top surface of the cavity is proposed as the driving force for the observed shift in WGMs, and is supported by experiments. The tuning for GaN/InGaN microdisk cavities is an important step for deterministically realizing novel nanophotonic devices for studying cavity quantum electrodynamics