King, Julian A., Mortlock, Daniel J., Webb, John K., Murphy, Michael T.
Recent attempts to constrain cosmological variation in the fine structure constant, alpha, using quasar absorption lines have yielded two statistical samples which initially appear to be...
Photometric constraints on white dwarfs and the identification of extreme objects (2008)
Mortlock, Daniel J., Peiris, Hiranya V., Ivezic, Zeljko
It is possible to reliably identify white dwarfs (WDs) without recourse to spectra, instead using photometric and astrometric measurements to distinguish them from Main Sequence stars and quasars....
The UKIRT Infrared Deep Sky Survey and the search for the most distant quasars (2008)
Mortlock, Daniel J., Patel, Mitesh, Warren, Stephen J., Venemans, Bram P., McMahon, Richard G., Hewett, Paul, ...
The UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) has the necessary combination of filters (Y, J, H and K), depth (Y ~ 6.4 quasars. The Third Data Release (DR3) included ~1000 deg^2...
Neutrino Interferometry In Curved Spacetime (2003)
Crocker, Roland M., Giunti, Carlo, Mortlock, Daniel J.
Gravitational lensing introduces the possibility of multiple (macroscopic) paths from an astrophysical neutrino source to a detector. Such a multiplicity of paths can allow for quantum mechanical...
Joint Analysis of CMB Temperature and Polarization Power Spectra (2002)
Munshi, Dipak, Challinor, Anthony D., Doré, Olivier, Mortlock, Daniel J., Efstathiou, George P.
This paper has been withdrawn. It was an early draft submitted prematurely in error. A complete version is to be submitted shortly.
Spectroscopic detection of quasars in the 2dF Galaxy Redshift Survey (2002)
Madgwick, Darren S., Hewett, Paul C., Mortlock, Daniel J., Lahav, Ofer
The 100,000 spectra from the 2 degree Field Galaxy Redshift Survey (2dFGRS) in the 100k Public Data Release represent the largest single compilation of galaxy spectra available. By virtue of its...
Van Leeuwen, Floor, Challinor, Anthony D., Mortlock, Daniel J., Ashdown, Mark A. J., Hobson, Michael P., Lasenby, Anthony N., ...
We present a harmonic model for the data analysis of an all-sky cosmic microwave background survey, such as Planck, where the survey is obtained through ring-scans of the sky. In this model,...
Harmonic analysis of cosmic microwave background data II: from ring-sets to the sky (2001)
Challinor, Anthony D., Mortlock, Daniel J., Van Leeuwen, Floor, Lasenby, Anthony N., Hobson, Michael P., Ashdown, Mark A. J., ...
Despite the fact that the physics of the cosmic microwave background anisotropies is most naturally expressed in Fourier space, pixelised maps are almost always used in the analysis and simulation of...
Empirical constraints on alternative gravity theories from gravitational lensing (2001)
Mortlock, Daniel J., Turner, Edwin L.
If it is hypothesised that there is no dark matter then some alternative gravitational theory must take the place of general relativity (GR) on the largest scales. Dynamical measurements can be used...
Gravitational lensing in modified Newtonian dynamics (2001)
Mortlock, Daniel J., Turner, Edwin L.
Modified Newtonian dynamics (MOND) is an alternative theory of gravity that aims to explain large-scale dynamics without recourse to any form of dark matter. However the theory is incomplete, lacking...
Using the 6dF galaxy redshift survey to detect gravitationally-lensed quasars (2001)
Mortlock, Daniel J., Drinkwater, Michael J.
It is possible to detect gravitationally-lensed quasars spectroscopically if the spectra obtained during galaxy surveys are searched for the presence of quasar emission lines. The up-coming 6 degree...
The 2dF gravitational lens survey (2001)
Mortlock, Daniel J., Madgwick, Darren S., Lahav, Ofer
The 2 degree Field (2dF) galaxy redshift survey will involve obtaining approximately 2.5 x 10^5 spectra of objects previously identified as galaxy candidates on morphological grounds. Included in...
Gravitational lensing and modified Newtonian dynamics (2001)
Mortlock, Daniel J., Turner, Edwin L.
Gravitational lensing is most often used as a tool to investigate the distribution of (dark) matter in the universe, but, if the mass distribution is known a priori, it becomes, at least in...
Gravitational lensing and elliptical galaxies (2000)
Mortlock, Daniel J., Webster, Rachel L.
If the statistics of quasar lensing are to be used to constrain the cosmological model, the various potential systematic uncertainties in the deflector population must be accounted for. One ambiguity...
Using the 2dF galaxy redshift survey to detect gravitationally-lensed quasars (2000)
Mortlock, Daniel J., Webster, Rachel L.
Galaxy redshift surveys can be used to detect gravitationally-lensed quasars if the spectra obtained are searched for the quasars' emission lines. Previous investigations of this possibility have...
The statistics of wide-separation lenses (2000)
The probability that high-redshift sources are gravitationally-lensed with large image separations (i.e., greater than can be produced by galactic deflectors) is determined by the cosmological...
Gravitational lensing in galaxy redshift surveys (2000)
Mortlock, Daniel J., Webster, Rachel L.
Gravitationally-lensed quasars should be discovered as a by-product of large galaxy redshift surveys, being discovered spectroscopically when a low-redshift galaxy exhibits high-redshift quasar...
Gravitational lensing by elliptical galaxies (2000)
Mortlock, Daniel J., Webster, Rachel L.
The fraction of high-redshift sources which are multiply-imaged by intervening galaxies is strongly dependent on the cosmological constant, and so can be a useful probe of the cosmological model....
The statistics of wide-separation lensed quasars (2000)
Mortlock, Daniel J., Webster, Rachel L.
The absence of any wide-separation gravitational lenses in the Large Bright Quasar Survey is used to place limits on the population of cluster-sized halos in the universe, and hence constrain a...
Using galaxy redshift surveys to detect gravitationally-lensed quasars (2000)
Mortlock, Daniel J., Webster, Rachel L.
Gravitationally-lensed quasars can be discovered as a by-product of galaxy redshift surveys. Lenses discovered spectroscopically in this way should require less observational effort per event than...
Analysis of cosmic microwave background data on an incomplete sky (2000)
Mortlock, Daniel J., Challinor, Anthony D., Hobson, Michael P.
Measurement of the angular power spectrum of the cosmic microwave background is most often based on a spherical harmonic analysis of the observed temperature anisotropies. Even if all-sky maps are...
Mortlock, Daniel J., Webster, Rachel L., Francis, Paul J.
Quasar pairs are either physically distinct binary quasars or the result of gravitational lensing. The majority of known pairs are in fact lenses, with a few confirmed as binaries, leaving a...
The Ray Bundle method for calculating weak magnification by gravitational lenses (1998)
Fluke, C. J., Webster, R. L., Mortlock, Daniel J.
We present here an alternative method for calculating magnifications in gravitational lensing calculations -- the Ray Bundle method. We provide a detailed comparison between the distribution of...