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In the first part of this thesis an automated polarimeter is described, and details are given of a dedicated CCD camera system based on a personal computer. The quality of the data produced by these instruments is demonstrated by the results presented in the succeeding chapters. Polarimetric observations of nebulae associated with two pre-MS objects, HH83/Rel7 and GL2591, and two post-MS objects, IRAS 07131-0147 and OH 231.8+4.2, are presented and discussed with reference to previous observations. In each case the location of the exciting source is determined and a simple model is described which explains the observed characteristics of the system. Both HH83/Rel7 and GL2591 are shown to be illuminated by nearby IRAS sources which have no optical counterparts. The nebula associated with HH83/Rel7 is caused by the reflection of radiation off the insides of the walls of a cavity excavated in the dark cloud by outflows from the IRS, and is crossed by a narrow unpolarised jet seen in emission-line radiation. The nebula associated with GL2591 is illuminated at optical wavelengths by both the IRS and a second, visible, source, and is composed of material ejected by the IRS in a discrete period of mass loss. IRAS 07131-0147 and OH 231.8+4.2 are shown to be stars which have evolved off the AGB and which will soon become the central stars of planetary nebulae. The protoplanetary nebulae which have formed as a result of the action of the fast stellar wind on the extended RGE around each star are bipolar and axially symmetric. The fast wind is shown to have ceased in the case of IRAS 07131-0147, but that related to OH 231.8+4.2 is still carrying material away from the star in a highly collimated fashion, producing narrow dusty filaments along the axes of the cavities. High levels of polarisation are measured in both nebulae, which indicates that the scattering particles are much smaller than those in the ISM.A brief comparison of the pre- and post-MS nebulae shows that the two phases of stellar evolution are linked by a number of observationally similar characteristics, and it is thought that similar processes may occur at opposite ends of the evolutionary track. Most notably, circumstellar discs appear to be common at various stages in the stellar life-cycle.

The large body of observations extant from pre-telescopic East Asia - China, Japan and Korea - provide the opportunity to investigate the behaviour of the Sun and solar system over a much longer period of time than that since telescopic observations began in Europe. Much past work in this field has tended to concentrate on individual records of particularly significant observations. In this study the variations in the frequency of the observation of meteors, comets, eclipses, planetary conjunctions and occupations, sunspots, and aurorae during the pre-telescopic period are examined in contemporary records from these three countries. It is to be expected that data artefacts (frequency variations not of astronomical origin) are present to some degree in early sources. The records are translated and collated where necessary, and by comparing patterns across the three countries and across different types of event several major data artefacts are identified and classified. The problem of such artefacts has not previously been the subject of analysis. The results of this study are therefore of significance in considering the reliability of these sets of data for the examination of long term variations in the solar system.

No description available.

Short hard gamma-ray bursts (GRB) are believed to be produced by compact binary coalescences (CBC) { either double neutron stars or neutron star{black hole binaries. The same source is expected to emit strong gravitational radiation, detectable with existing and planned gravitational wave observatories. The focus of this work is to describe a series of searches for gravitational waves (GW) from compact binary coalescence (CBC) events triggered by short gamma-ray burst detections. Specifically, we will present the motivation, frameworks, implementations and results of searches for GW associated with short gamma-ray bursts detected by Swift, Fermi{GBM and the InterPlanetary Network (IPN) gamma-ray detectors. We will begin by presenting the main concepts that lay the foundation of gravitational waves emission, as they are formulated in the theory of General Relativity; we will also brie y describe the operational principles of GW detectors, together with explaining the main challenges that the GW detection process is faced with. Further, we will motivate the use of observations in the electromagnetic (EM) band as triggers for GW searches, with an emphasis on possible EM signals from CBC events. We will briefly present the data analysis techniques including concepts as matched{filtering through a collection of theoretical GW waveforms, signal{to{ noise ratio, coincident and coherent analysis approaches, signal{based veto tests and detection candidates' ranking. We will use two different GW{GRB search examples to illustrate the use of the existing coincident and coherent analysis methods. We will also present a series of techniques meant to improve the sensitivity of existing GW triggered searches. These include shifting background data in time in order to obtain extended coincident data and setting a prior on the GRB inclination angle, in accordance with astrophysical observations, in order to restrict the searched parameter space. We will describe the GW data analysis and present results from a GW search around 12 short gamma-ray bursts detected by the InterPlanetary Network (IPN) between 2006 and 2007. The IPN{detected bursts usually have extended localization error boxes and a search for GW was performed at different sky locations across these error regions. Since no GW detection was made, we set upper limits on the distances to the GRB progenitors; we briefly discuss the implications that two IPN GRBs error regions overlap two nearby galaxies.

This thesis presents an investigation of local galaxies using new data from the Herschel Space Observatory. Herschel observes the entire far-infrared peak of galaxies, at higher sensitivities and angular resolution than previously possible, and can observe large samples of galaxies or areas of sky. I developed data reduction routines to optimise the data processing of SPIRE extragalactic fields, and found the best methods of flux extraction for galaxies and for fitting of spectral energy distributions. For all the objects I investigated, a single-temperature modified blackbody was a good fit to the global fluxes between 100–500 μm. Within an individual galaxy (i.e., M31, NGC4501 and NGC4567/8) the dust temperature varies between 15–30K. In M31 the dust emissivity index varies between 1.2–2.5 suggesting a change in the physical properties of the grains. The dust and gas are highly correlated in M31, with the gas-to-dust ratio varying from ∼20 in the centre to ∼200 at 18 kpc as expected from the metallicity gradient of the galaxy. By averaging the radial profiles of the late-type objects in the Herschel Reference Survey (HRS), I have shown that dust emission can be traced to at least twice the optical radius (R25) of the galaxy. Within the HRS, dust is detected in 24% of Ellipticals and 62% of S0s and has a mean temperature of 23.9 ± 0.8K for early-type galaxies, warmer than that found for other Herschel studies of late-type galaxies. The mean dust mass for the entire detected early-type sample is logMd = 6.1 ± 0.1M⊙ with a mean dust-to-stellar-mass ratio of log(Md/M∗) = −4.3 ± 0.1, a factor of ∼50 lower dust-to-stellar-mass ratio than for the spiral galaxies in the HRS. The wide range in the dust-to-stellar-mass ratio for ETGs and the lack of a correlation between dust mass and optical luminosity suggest that much of the dust in the ETGs detected by Herschel has been acquired as the result of interactions, although these are unlikely to have had a major effect on the stellar masses of the ETGs.

The main focus of the work described here within, is the development of an analysis pipeline that can detect gravitational waves transients that have a duration from a large fraction of a second up to 100 seconds. Firstly, we will present the basic theory of gravitational waves, their generation and their detection. We will then review the current state of the art of gravitational waves transient search algorithms and their limitations. We also introduce the coherent search pipeline that has been developed from the ground up to find such intermediate length gravitational waves, and discuss in detail how it differs from other pipelines, and what makes it so well suited to this task. Further, we will describe the powerful glitch rejection algorithm and sky localisation solution that using the spherical harmonic basis made possible. Finally, we demonstrate the use of this method on real data, and compare our results against a mature pipeline.

I present new optical and infrared photometry for a statistically complete sample of seven sources selected at 1.1 mm. Comparing their photometric redshifts with redshifts from previous 850 μm selected surveys indicates that 1.1 mm selected surveys may be better at finding high redshift sources. I also perform a banded Ve/Va analysis on the sample, and find no evidence for a redshift cutoff in the space density of sources. However, the sample size is very small. I perform the same analysis on a statistically complete sample of 38 galaxies selected at 850 μm. I find a evidence for a drop off in space density of sources beyond between z∼1-2 as well as for the existence of two differently evolving sub-populations separated in luminosity. I present a sample of SPIRE sources, selected at 250 μm, with a set of previously collected ancillary photometry and either spectroscopic or photometric redshifts. I find that only ∼1/4 of the sources at redshifts z∼1 show evidence of undergoing a major merger. I find evidence to support a downsizing model of galaxy evolution, where the most massive galaxies form first. I find some correlation with star formation rate and the gas mass of a galaxy, therefore the drop in cosmic star formation rate since z = 1 may be caused by a coinciding drop in the average gas mass of galaxies over this era. Finally, I discuss the possibility of using imaging spectrometers to break through the confusion limit. Taking the SAFARI instrument as a test case I find that I can uniquely identify galaxies by their redshift, determined via an automated method. I find that this method works for galaxies with fluxes as much as ten times below the traditional continuum confusion limit. I also find that I can uniquely identify spectrally confused sources