Lance Miller

Abstract:

A search is presented for stars that may have formed coevally with the apparently young halo star PHL 346. Candidates were selected for spectroscopy from UBR Schmidt Telescope plates in U.K. Schmidt Telescope survey field 603 scanned with the COSMOS facility at the Royal Observatory, Edinburgh. Spectroscopic observations at ∼ 3.5 Å resolution were made of 72 field stars using the 1.9m telescope at the South African Astronomical Observatory; 16 A- and B-type stars were found, one of which had the appropriate spectral type and radial velocity to be associated with PHL 346. Further photometry and spectroscopy confirmed this identification. The remaining low gravity early-type stars have a mean LSR radial velocity of -75 km s-1, consistent with a non-rotating halo Population.

Abstract:

We report on the development of a new method for detecting automatically malignant masses in digitised mammograms, based on a novel non-linear method of multiscale analysis. We show that it is possible to detect > 85 percent of all malignant masses by this method, irrespective of their size, with a false-alarm rate that is close to acceptable for asymptomatic screening.

Abstract:

This is the first paper in a series aimed at defining a statistically significant sample of QSOs in the range $ 15 < B < 18.75$ and $ 0.3 < z < 2.2$. The selection is carried out using direct plates obtained at the ESO and UK Schmidt Telescopes, scanned with the COSMOS facility and searched for objects with an ultraviolet excess. Follow-up spectroscopy, carried out at ESO La Silla, is used to classify each candidate. In this initial paper, we describe the scientific objectives of the survey; the selection and observing techniques used. We present the first sample of 285 QSOs ($M_B < -23$) in a 153 deg$^2$ area, covered by the six ``deep'' fields, intended to obtain significant statistics down $B \simeq 18.75$ with unprecedented photometric accuracy. From this database, QSO counts are determined in the magnitude range $ 17 < B < 18.75$.

Abstract:

We present a redshift survey of 124 galaxies, from an imaging $K$-band survey complete to $K\simeq 17.3$. The optical-to-infrared colours are consistent with the range expected from synthetic galaxy spectra, although there are some cases of very red nuclei. Our data show no evidence for evolution of the $K$-band luminosity function at $z<0.5$, and the results are well described by a Schechter function with $M_K^*=-22.75\pm0.13+5\log_{10}h$ and $\phi^*=0.026\pm0.003 h^3 {\rm Mpc^{-3}}$. This is a somewhat higher normalization than has been found by previous workers, and it removes much of the excess in faint $K$ and $B$ counts with respect to a no-evolution model. However, we do find evidence for evolution at $z>0.5$: $M_K^*$ is approximately 0.75 mag. brighter at $z=1$. This luminosity evolution is balanced by a reduced normalization at high redshift. The overall evolution is thus opposite to that expected in simple merger-dominated models.