Euclid

Research group

Research theme

Sub department

About

Related research groups

The halo formation rate and its link to the global star formation rate

ASTR SOC P 193 (1999) 525-528

Authors:

W Percival, L Miller, B Ballinger

Abstract:

The star formation history of the universe shows strong evolution with cosmological epoch. Although we know mergers between galaxies can cause luminous bursts of star formation, the relative importance of such mergers to the global star formation rate (SFR) is unknown. We present a simple analytic formula for the rate at which halos merge to form higher-mass systems, derived from Press-Schechter theory and confirmed by numerical simulations (for high halo masses). A comparison of the evolution in halo formation rate with the observed evolution in the global SFR indicates that the latter is largely driven by halo mergers at z > 1. Recent numerical simulations by Kolatt et al. (1999) and Knebe & Muller (1999) show how merging systems are strongly biased tracers of mass fluctuations, thereby explaining the strong clustering observed for Lyman-break galaxies without any need to assume that Lyman-break galaxies are associated only with the most massive systems at z similar to 3.
More details
Details from ArXiV

The 2dF QSO Redshift Survey

ArXiv astro-ph/9810127 (1998)

Authors:

SM Croom, T Shanks, BJ Boyle, RJ Smith, L Miller, NS Loaring

Abstract:

We present preliminary results from the 2-degree Field (2dF) QSO Redshift Survey currently under way at the Anglo-Australian Telescope. This survey aims to determine the redshifts of >25000 QSOs over a redshift range of 0.3
Details from ArXiV
More details from the publisher

The galaxy halo formation rate

ArXiv astro-ph/9809330 (1998)

Authors:

WJ Percival, L Miller

Abstract:

The rate at which galaxy halos form is thought to play a key role in explaining many observable cosmological phenomena such as the initial epoch at which luminous matter forms and the distribution of active galaxies. Here we show how Press-Schechter theory can be used to provide a simple, completely analytic model of the halo formation rate. This model shows good agreement with both Monte-Carlo and N-body simulation results.
Details from ArXiV

Precision astrometry with SuperCOSMOS

Monthly Notices of the Royal Astronomical Society 298:3 (1998) 897-904

Authors:

NC Hambly, L Miller, HT MacGillivray, JT Herd, WA Cormack

Abstract:

We describe the new, fast, high-precision microdensitometer SuperCOSMOS. Some aspects of hardware and software design that enable high-precision astrometry from photographic plates are explained. We show that the positioning repeatability of the measuring machine is less than 0.1 μm standard error in either coordinate, and the absolute positional accuracy is about 0.15 μm standard error. Furthermore, measurements of the same plate in different orientations show that the sampling errors are small (e.g. ∼0.2 μm, rising to ∼1.0 μm at the plate limit, for stellar images in a IIIaJ emulsion), thus allowing the extraction of relative positional information from Schmidt plates at accuracies less than 1 μm. We demonstrate that SuperCOSMOS is capable of measuring the positions of bright stars (i.e. those more than ∼4 mag above the plate limit) to a precision ∼0.5 μm with survey-grade photographic plates employing fine-grained emulsions.
More details from the publisher

A bright QSO near 3C273

ASTRONOMY & ASTROPHYSICS 335:1 (1998) 121-122

Authors:

MA Read, L Miller, G Hasinger
More details