engFarrah, DFox, MRowan-Robinson, MClements, DAfonso, JSub-millimeter emission from type Ia supernova host galaxies at z=0.5Astrophysics and Astronomyastro-ph/0312111We present deep sub-millimetre observations of seventeen galaxies at z=0.5, selected through being hosts of a type 1a supernova. Two galaxies are detected directly, and the sample is detected statistically with a mean 850 micron flux of 1.01mJy +/- 0.33mJy, which is 25% - 135% higher than locally. We infer that the mean value of A_v in normal galaxies at z=0.5 is comparable to or greater than the mean A_v in local normal galaxies, in agreement with galaxy chemical evolution models and indirect observational evidence. Scaling from the local value given by Rowan-Robinson (2003) gives a mean extinction at z=0.5 of A_v = 0.56 +/- 0.17. The dust in the brightest sub-mm object in our sample is best interpreted as normal `cirrus' dust similar to that seen locally. The detection rate of our sample suggests that some sources found in blank-field sub-mm surveys may not be high redshift starbursts, but rather cirrus galaxies at moderate redshifts and with lower star formation rates. Finally, an increase in host dust extinction with redshift may impact the cosmological results from distant supernova searches. This emphasizes the need to carefully monitor dust extinction when using type Ia supernovae to measure the cosmological parameters.2003-12-03http://cds.cern.ch/record/689750http://cds.cern.ch/record/689750oai:cds.cern.ch:689750 engCaldwell, R RDoran, MCosmic Microwave Background and Supernova Constraints on Quintessence: Concordance Regions and Target ModelsAstrophysics and Astronomyastro-ph/0305334We perform a detailed comparison of the Wilkinson Microwave Anisotropy Probe (WMAP) measurements of the cosmic microwave background (CMB) temperature and polarization anisotropy with the predictions of quintessence cosmological models of dark energy. We consider a wide range of quintessence models, including: a constant equation-of-state; a simply-parametrized, time-evolving equation-of-state; a class of models of early quintessence; scalar fields with an inverse-power law potential. We also provide a joint fit to the CBI and ACBAR CMB data, and the type 1a supernovae. Using these select constraints we identify viable, target models for further analysis.2003-05-19http://cds.cern.ch/record/623475http://cds.cern.ch/record/623475oai:cds.cern.ch:623475 engMinty, E MHeavens, A FHawkins, M R STesting dark matter with high-redshift supernovaeAstrophysics and Astronomyastro-ph/0104221Dark matter in the Universe consisting of macroscopic objects such as primordial black holes may cause gravitational lensing of distant objects. The magnification associated with lensing will lead to additional scatter in the received flux from standard candles, and too small an observed scatter could rule out compact dark matter entirely. In this letter, we show how the scatter in fluxes of distant Type 1a supernovae could be used to distinguish between models with and without lensing by macroscopic dark matter. The proposed SNAP project, with $\sim 2400$ supernovae in the range $0.1\ls z\ls 1.7$, should be able to identify models at 99.9% confidence, if systematic errors are controlled. Note that this test is independent of any evolution of the mean supernova luminosity with redshift. The variances of the current Supernova Cosmology Project sample do not rule out compact lenses as dark matter: formally they favour such a population, but the significance is low, and removal of a single faint supernova from the sample reverses the conclusion.2001-04-12http://cds.cern.ch/record/496079http://cds.cern.ch/record/496079oai:cds.cern.ch:496079 engEfstathiou, G PLasenby, A NHobson, M PEllis, Richard SBridle, S LConstraints on $\Omega_{\Lambda}$ and $\Omega_{m}$from Distant Type 1a Supernovae and Cosmic Microwave Background AnisotropiesAstrophysics and Astronomyastro-ph/9812226We perform a combined likelihood analysis of the latest cosmic microwave background anisotropy data and distant Type 1a Supernova data of Perlmutter etal (1998a). Our analysis is restricted to cosmological models where structure forms from adiabatic initial fluctuations characterised by a power-law spectrum with negligible tensor component. Marginalizing over other parameters, our best fit solution gives Omega_m = 0.25 (+0.18, -0.12) and Omega_Lambda = 0.63 (+0.17, -0.23) (95 % confidence errors) for the cosmic densities contributed by matter and a cosmological constant respectively. The results therefore strongly favour a nearly spatially flat Universe with a non-zero cosmological constant.1998-12-14http://cds.cern.ch/record/374135http://cds.cern.ch/record/374135oai:cds.cern.ch:374135