A B S T R A C TThe 2dF Galaxy Redshift Survey (2dFGRS) is designed to measure redshifts for approximately 250 000 galaxies. This paper describes the survey design, the spectroscopic observations, the redshift measurements and the survey data base. The 2dFGRS uses the 2dF multifibre spectrograph on the Anglo-Australian Telescope, which is capable of observing 400 objects simultaneously over a 28 diameter field. The source catalogue for the survey is a revised and extended version of the APM galaxy catalogue, and the targets are galaxies with extinction-corrected magnitudes brighter than b J ¼ 19:45. The main survey regions are two declination strips, one in the southern Galactic hemisphere spanning 808 Â 158 around the SGP, and the other in the northern Galactic hemisphere spanning 758 Â 108 along the celestial equator; in addition, there are 99 fields spread over the southern Galactic cap. The survey covers 2000 deg 2 and has a median depth of z ¼ 0:11. Adaptive tiling is used to give a highly uniform sampling rate of 93 per cent over the whole survey region. Redshifts are measured from spectra covering 3600-8000A at a two-pixel resolution of 9.0 Å and a median S/N of 13 pixel 21 . All redshift identifications are visually checked and assigned a quality parameter Q in the range 1-5; Q $ 3 redshifts are 98.4 per cent reliable and have an rms uncertainty of 85 km s 21 . The overall redshift completeness for Q $ 3 redshifts is 91.8 per cent, but this varies with magnitude from 99 per cent for the brightest galaxies to 90 per cent for objects at the survey limit. The 2dFGRS data base is available on the World Wide Web at http://www. mso.anu.edu.au/2dFGRS.

We report on our search for microlensing towards the Large Magellanic Cloud (LMC). Analysis of 5.7 years of photometry on 11.9 million stars in the LMC reveals 13 -17 microlensing events. A detailed treatment of our detection efficiency shows that this is significantly more than the ∼ 2 to 4 events expected from lensing by known stellar populations. The timescales ( t ) of the events range from 34 to 230 days. We estimate the microlensing optical depth towards the LMC from events with 2 < t < 400 days to be τ 400 2 = 1.2 +0.4 −0.3 × 10 −7 , with an additional 20% to 30% of systematic error. The spatial distribution of events is mildly inconsistent with LMC/LMC disk self-lensing, but is consistent with an extended lens distribution such as a Milky Way or LMC halo. Interpreted in the context of a Galactic dark matter halo, consisting partially of compact objects, a maximum likelihood analysis gives a MACHO halo fraction of 20% for a typical halo model with a 95% confidence interval of 8% to 50%. A 100% MACHO halo is ruled out at the 95% C.L. for all except our most extreme halo model. Interpreted as a Galactic halo population, the most likely MACHO mass is between 0.15 M ⊙ and 0.9 M ⊙ , depending on the halo model, and the total mass in MACHOs out to 50 kpc is found to be 9 +4 −3 × 10 10 M ⊙ , independent of the halo model. These results are marginally consistent with our previous results, but are lower by about a factor of two. This is mostly due to Poisson noise because with 3.4 times more exposure and increased sensitivity to long timescale events, we did not find the expected factor of ∼ 4 more events. Besides a larger data set, this work also includes an improved efficiency determination, improved likelihood analysis, and more thorough testing of systematic errors, especially with respect to the treatment of potential backgrounds to microlensing. We note that an important source of background are supernovae in galaxies behind the LMC.

We present a power-spectrum analysis of the final 2dF Galaxy Redshift Survey (2dFGRS), employing a direct Fourier method. The sample used comprises 221 414 galaxies with measured redshifts. We investigate in detail the modelling of the sample selection, improving on previous treatments in a number of respects. A new angular mask is derived, based on revisions to the photometric calibration. The redshift selection function is determined by dividing the survey according to rest-frame colour, and deducing a self-consistent treatment of k-corrections and evolution for each population. The covariance matrix for the power-spectrum estimates is determined using two different approaches to the construction of mock surveys, which are used to demonstrate that the input cosmological model can be correctly recovered. We discuss in detail the possible differences between the galaxy and mass power spectra, and treat these using simulations, analytic models and a hybrid empirical approach. Based on these investigations, we are confident that the 2dFGRS power spectrum can be used to infer the matter content of the universe. On large scales, our estimated power spectrum shows evidence for the 'baryon oscillations' that are predicted in cold dark matter (CDM) models. Fitting to a CDM model, assuming a primordial n s = 1 spectrum, h = 0.72 and negligible neutrino mass, the preferred parameters are m h = 0.168 ± 0.016 and a baryon fraction b / m = 0.185 ± 0.046 (1σ errors). The value of m h is 1σ lower than the 0.20 ± 0.03 in our 2001 analysis of the partially E-mail: shaun.cole@durham.ac.uk C 2005 RAS 506 S. Cole et al.complete 2dFGRS. This shift is largely due to the signal from the newly sampled regions of space, rather than the refinements in the treatment of observational selection. This analysis therefore implies a density significantly below the standard m = 0.3: in combination with cosmic microwave background (CMB) data from the Wilkinson Microwave Anisotropy Probe (WMAP), we infer m = 0.231 ± 0.021.

We combine the Two Micron All Sky Survey (2MASS) Extended Source Catalogue and the 2dF Galaxy Redshift Survey to produce an infrared selected galaxy catalogue with 17 173 measured redshifts. We use this extensive data set to estimate the galaxy luminosity functions in the J‐ and KS‐bands. The luminosity functions are fairly well fitted by Schechter functions with parameters MJ*−5 log  h=−22.36±0.02, αJ=−0.93±0.04, ΦJ*=0.0104±0.0016 h3 Mpc−3 in the J‐band and MKS*−5 log  h=−23.44±0.03, αKS=−0.96±0.05, ΦKS*=0.0108±0.0016 h3 Mpc−3 in the KS‐band (2MASS Kron magnitudes). These parameters are derived assuming a cosmological model with Ω0=0.3 and Λ0=0.7. With data sets of this size, systematic rather than random errors are the dominant source of uncertainty in the determination of the luminosity function. We carry out a careful investigation of possible systematic effects in our data. The surface brightness distribution of the sample shows no evidence that significant numbers of low surface brightness or compact galaxies are missed by the survey. We estimate the present‐day distributions of bJ−KS and J−KS colours as a function of the absolute magnitude and use models of the galaxy stellar populations, constrained by the observed optical and infrared colours, to infer the galaxy stellar mass function. Integrated over all galaxy masses, this yields a total mass fraction in stars (in units of the critical mass density) of Ωstarsh =(1.6±0.24)×10−3 for a Kennicutt initial mass function (IMF) and Ωstarsh =(2.9±0.43)×10−3 for a Salpeter IMF. These values are consistent with those inferred from observational estimates of the total star formation history of the Universe provided that dust extinction corrections are modest.

Summary 0[ Dispersal is of critical ecological and evolutionary importance for several issues of population biology\ particularly population synchrony\ colonization and range expansion\ metapopulation and sourceÐsink dynamics\ and population genetic struc! ture\ but it has not previously been possible to compare dispersal patterns across a wide range of species or to study movement outside the con_nes of local study areas[ 1[ Using resampling methods\ we veri_ed that statistically unbiased estimates of average dispersal distance and of intraspeci_c variance in dispersal distance could be extracted from the bird ringing data of the British Trust for Ornithology[ 2[ Using data on 64 terrestrial bird species\ we tested whether natal and breeding dispersal were in~uenced by a species| habitat requirements\ diet\ geographical range\ abundance\ morphology\ social system\ life history or migratory status[ We used allometric techniques to ascertain whether these relationships were independent of body size\ and used the method of phylogenetically independent contrasts to ascertain whether they were independent of phylogeny[ 3[ Both natal and breeding dispersal distances were lower among abundant species and among species with large geographical ranges[ Dispersal distances and life!history variables were correlated independent of phylogeny\ but these relationships did not persist after controlling for body size[ All morphometrical variables "wing length\ tarsus length and bill length# were not signi_cantly correlated with dispersal distances after correcting for body size or phylogenetic relatedness[ 4[ Migrant species disperse further than resident ones\ this relation was independent of body size but not of phylogeny[ A signi_cant positive relation was observed between breeding dispersal distance and long!term population decline among migrants\ but not among residents[ 5[ The species living in wet habitats disperse further than those living in dry habitats\ which could be explained by the greater patchiness of wet habitats in space and:or time[ This relationship was observed only for breeding dispersal\ suggesting that this habitat variable does not impose the same constraint on natal dispersal[ Key!words] body size\ comparative analyses\ dispersal distances\ phylogeny\ ring recoveries[ Journal of Animal Ecology "0887# 56\ 407Ð425

This paper describes the first catalogue of photometrically-derived stellar mass estimates for intermediate-redshift (z < 0.65; median z = 0.2) galaxies in the Galaxy And Mass Assembly (GAMA) spectroscopic redshift survey. These masses, as well as the full set of ancillary stellar population parameters, will be made public as part of GAMA data release 2. Although the GAMA database does include NIR photometry, we show that the quality of our stellar population synthesis fits is significantly poorer when these NIR data are included. Further, for a large fraction of galaxies, the stellar population parameters inferred from the optical-plus-NIR photometry are formally inconsistent with those inferred from the optical data alone. This may indicate problems in our stellar population library, or NIR data issues, or both; hese issues will be addressed for future versions of the catalogue. For now, we have chosen to base our stellar mass estimates on optical photometry only. In light of our decision to ignore the available NIR data, we examine how well stellar mass can be constrained based on optical data alone. We use generic properties of stellar population synthesis models to demonstrate that restframe colour alone is in principle a very good estimator of stellar mass-to-light ratio, M * /L i . Further, we use the observed relation between restframe (g − i) and M * /L i for real GAMA galaxies to argue that, modulo uncertainties in the stellar evolution models themselves, (g − i) colour can in practice be used to estimate M * /L i to an accuracy of 0.

The MACHO Project is a search for dark matter in the form of massive compact halo objects (MACHOs). Photometric monitoring of millions of stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge is used to search for gravitational microlensing events caused by these otherwise invisible objects. Analysis of the Ðrst 2.1 yr of photometry of 8.5 million stars in the LMC reveals eight candidate microlensing events. This is substantially more than the number expected (D1.1) from lensing by known stellar populations. The timescales (t) of the events range from 34 to 145 days. We estimate the total microlensing optical depth toward the LMC from events with days to be based upon our eight event sample. This exceeds the 2 \ tü \ 200 q 2 200 \ 2.9~0 .9 1.4 ] 10~7 optical depth, expected from known stars, and the di †erence is to be compared q backgnd \ 0.5 ] 10~7, with the optical depth predicted for a "" standard ÏÏ halo composed entirely of MACHOs : q halo \ 4.7 To compare with Galactic halo models, we perform likelihood analyses on the full eight-event ] 10~7. sample and a six-event subsample (which allows for two events to be caused by a nonhalo "" background ÏÏ). This gives a fairly model-independent estimate of the halo mass in MACHOs within 50 kpc of which is about half of the "" standard halo ÏÏ value. We also Ðnd a most prob-2.0~0 .71.2 ] 1011 M _ , able MACHO mass of although this value is strongly model dependent. In addition, the 0.5~0 .2 0.3 M _ , absence of short duration events places stringent upper limits on the contribution of low-mass MACHOs : objects from 10~4 to 0.03 contribute of the "" standard ÏÏ dark halo.

We compute the bispectrum of the 2dF Galaxy Redshift Survey (2dFGRS) and use it to measure the bias parameter of the galaxies. This parameter quantifies the strength of clustering of the galaxies relative to the mass in the Universe. By analysing 80 × 10 6 triangle configurations in the wavenumber range 0.1 < k < 0.5 h Mpc −1 (i.e. on scales roughly between 5 and 30 h −1 Mpc) we find that the linear bias parameter is consistent with unity: b 1 = 1.04 ± 0.11, and the quadratic (non-linear) bias is consistent with zero: b 2 = −0.054 ± 0.08. Thus, at least on large scales, optically selected galaxies do indeed trace the underlying mass distribution. The bias parameter can be combined with the 2dFGRS measurement of the redshift distortion parameter β 0.6 m /b 1 , to yield m = 0.27 ± 0.06 for the matter density of the Universe, a result that is determined entirely from this survey, independent of other data sets. Our measurement of the matter density of the Universe should be interpreted as m at the effective redshift of the survey (z = 0.17).