M. G. Edmunds

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Using a new technique we have determined a value for the constant of proportionality between submillimetre (submm) emission and dust mass, the dust mass absorption coefficient (κd) at 850μm. Our method has an advantage over previous methods in that we avoid assumptions about the properties of dust in the interstellar medium. Our only assumption is that the(More)
We investigate the sources and amount of dust in early galaxies. We discuss dust nucleation in stellar atmospheres using published extended atmosphere models, stellar evolution tracks and nucleation conditions. The Thermally Pulsating Asymptotic Giant Branch (TPAGB) phase of intermediate mass stars is likely to be the most promising site for dust formation(More)
We present critical, long-wavelength observations of η Carinae in the submillimetre using SCUBA on the JCMT at 850 and 450 μm to confirm the presence of a large mass of warm dust around the central star. We fit a two-component blackbody to the IR-submm spectral energy distribution (SED) and estimate between 0.3− 0.7 M⊙ of dust exists in the nebula depending(More)
We employ analytical and numerical chemical evolution models to study observed trends in abundance ratios involving carbon, nitrogen, and oxygen. Several sets of published stellar yields for both intermediate-mass and massive stars are considered, and the most appropriate sets are selected through the use of analytical models. These yields are then used in(More)
The timescales to replenish dust from the cool, dense winds of Asymptotic Giant Branch stars are believed to be greater than the timescales for dust destruction. In high redshift galaxies, this problem is further compounded as the stars take longer than the age of the Universe to evolve into the dust production stages. To explain these discrepancies, dust(More)
Doing arithmetic has probably been necessary since civilisation began. We now know that the ancient Greeks were able to make mechanical devices capable of calculation. The Antikythera Mechanism is an extraordinary device containing over thirty gear wheels dating from the 1st century B.C., and is an order of magnitude more complicated than any surviving(More)
It has been suggested by Dwek (2004) that iron needles could explain the submillimetre emission from the Cas A supernova remnant (SNR) with only a very small total mass. We investigate whether a similar model holds for the Kepler supernova remnant, and find that its emission could indeed be explained by a dust mass of less than 10M⊙, dependent on the axial(More)
We construct a simple, robust model of the chemical evolution of galaxies from high to low redshift, and apply it to published observations of damped Lyman-alpha quasar absorption line systems (DLAs). The elementary model assumes quiescent star formation and isolated galaxies (no interactions, mergers or gas flows). We consider the influence of dust and(More)