We report the final redshift release of the 6dF Galaxy Survey (6dFGS), a combined redshift and peculiar velocity survey over the southern sky (|b| > 10°). Its 136 304 spectra have yielded 110 256 new extragalactic redshifts and a new catalogue of 125 071 galaxies making near‐complete samples with (K, H, J, rF, bJ) ≤ (12.65, 12.95, 13.75, 15.60, 16.75). The median redshift of the survey is 0.053. Survey data, including images, spectra, photometry and redshifts, are available through an online data base. We describe changes to the information in the data base since earlier interim data releases. Future releases will include velocity dispersions, distances and peculiar velocities for the brightest early‐type galaxies, comprising about 10 per cent of the sample. Here we provide redshift maps of the southern local Universe with z≤ 0.1, showing nearby large‐scale structures in hitherto unseen detail. A number of regions known previously to have a paucity of galaxies are confirmed as significantly underdense regions. The URL of the 6dFGS data base is http://www-wfau.roe.ac.uk/6dFGS.

We present spectroscopic linestrength data for 4097 red-sequence galaxies in 93 low-redshift galaxy clusters, and use these to investigate variations in average stellar populations as a function of galaxy mass. Our analysis includes an improved treatment of nebular emission contamination, which affects ∼ 10% of the sample galaxies. Using the stellar population models of D. Thomas and collaborators, we simultaneously fit twelve observed linestrength−σ relations in terms of common underlying trends of age, [Z/H] (total metallicity) and [α/Fe] (α-element enhancement). We find that the observed linestrength-σ relations can be explained only if higher-mass red-sequence galaxies are, on average, older, more metal rich, and more α-enhanced than lower-mass galaxies. Quantitatively, the scaling relations are age ∝ σ 0.59±0.13 , Z/H ∝ σ 0.53±0.08 and α/Fe ∝ σ 0.31±0.06 , where the errors reflect the range obtained using different subsets of indices. Our conclusions are not strongly dependent on which Balmer lines are used as age indicators. The derived age−σ relation is such that if the largest (σ ∼ 400 km s −1 ) galaxies formed their stars ∼ 13 Gyr ago, then the mean age of low-mass (σ ∼ 50 km s −1 ) objects is only ∼4 Gyr. The data also suggest a large spread in age at the low-mass end of the red sequence, with 68% of the galaxies having ages between 2 and 8 Gyr. We conclude that although the stars in giant red galaxies in clusters formed early, most of the galaxies at the faint end joined the red sequence only at recent epochs. This "down-sizing" trend is in good qualitative agreement with observations of the red sequence at higher redshifts, but is not predicted by semianalytic models of galaxy formation.

We have undertaken a detailed comparison of the colours of early-type galaxies in the Virgo and Coma clusters. In Paper I (this issue), we presented our system of homogeneous U, V, J and K photometric measurements for these galaxies. In this paper, we use this data set to investigate the universality of the colour-magnitude correlation. Our work reassesses the anomaly noted by Aaronson, Persson & Frogel. Following these authors, we initially compare the relative distances of the two clusters derived from the L-a and U-V and V-K colour-magnitude correlations. However, in contrast to their result, we find that all three relations give compatible relative distance moduli: llmu-v= 4.01±0.20, llmv-K= 3.58 ± 0.23, llmL-a= 3.62 ± 0.16. A similar result is found by correlating the colours and velocity dispersions with photometric diameters. Again, we find that all three comparisons give consistent distance estimates: llmu-v=3.87±0.15, llmv-K=3.42±0.21, llmD_a= 3.67 ± 0.11, with a mean relative distance modulus of 3.69 ± 0.08. These results show that the colour-magnitude relation has the same form in both Coma and Virgo. An alternative approach is to compare the colours of the galaxies directly through the distance-independent correlation between colour and velocity dispersion. We find that the median colours are offset by -0.009± 0.012 ( U-V), 0.005 ±0.016 ( V-K) and -0.038 ± 0.012 (J-K), with an estimated systematic error of 0.02, 0.03 and 0.04 mag in each case. All of these offsets are therefore consistent with there being no intrinsic difference between the colours of early-type galaxies in Virgo and Coma. We conclude that the colour-magnitude relation has the same form in both clusters, and hence can provide a reliable cosmic distance estimator for clusters of galaxies, giving relative distances accurate to -20 per cent per galaxy.In addition, our data constrain the intrinsic scatter of early-type galaxies about the mean colour-magnitude relation. We measure an rms scatter of typically 0.05 mag, of which -0.03 mag can be accounted for by observational error. By examining the correlation of residuals, we show that this intrinsic variation is unlikely to be dominated by differences in the star formation histories of elliptical galaxies. We use the stellar population synthesis model of Bruzuaf to quantify the implications of this result. First, we present simple time-scale arguments to suggest that the spheroidal components of early-type galaxies are unlikely to have formed below a redshift of 2( q 0 = 0.5 ). Secondly, we show that our data are only marginally consistent with the strong bursts of star formation required to explain the spectra of galaxies in moderate-redshift clusters. A reliable system of extragalactic distance indicators would allow modern telescopes to measure peculiar velocities and hence map the density structure of the local Universe. One indicator that has not yet been fully exploited is the colour-magnitude (C-M) relation for early-type galaxies. This relation was first established by Baum (1959)...

The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z < 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. The survey region is a stripe 2.5• wide centered on the celestial equator in the Southern Galactic Cap that has been imaged numerous times in earlier years, enabling construction of a deep reference image for the discovery of new objects. Supernova imaging observations are being acquired between September 1 and November 30 of 2005-7. During the first two seasons, each region was imaged on average every five nights. Spectroscopic follow-up observations to determine supernova type and redshift are carried out on a large number of telescopes. In its first two three-month seasons, the survey has discovered and measured light curves for 327 spectroscopically confirmed SNe Ia, 30 probable SNe Ia, 14 confirmed SNe Ib/c, 32 confirmed SNe II, plus a large number of photometrically identified SNe Ia, 94 of which have host-galaxy spectra taken so far. This paper provides an overview of the project and briefly describes the observations completed during the first two seasons of operation.

We investigate the Mg–σ and 〈Fe〉–σ relations in a sample of 72 early‐type galaxies drawn mostly from cluster and group environments using a homogeneous data set which is well calibrated on to the Lick/IDS system. The small intrinsic scatter in Mg at a given σ gives upper limits on the spread in age and metallicity of 49 and 32 per cent respectively, if the spread is attributed to one quantity only, and if the variations in age and metallicity are uncorrelated. The age/metallicity distribution as inferred from the Hβ versus 〈Fe〉 diagnostic diagram reinforces this conclusion, as we find mostly galaxies with large luminosity‐weighted ages spanning a range in metallicity. Using Monte Carlo simulations, we show that the galaxy distribution in the Hβ versus 〈Fe〉 plane cannot be reproduced by a model in which galaxy age is the only parameter driving the index–σ relation. In our sample we do not find significant evidence for an anticorrelation of ages and metallicities which would keep the index–σ relations tight while hiding a large spread in age and metallicity. As a result of correlated errors in the age–metallicity plane, a mild age–metallicity anticorrelation cannot be completely ruled out by the current data. Correcting the line‐strength indices for non‐solar abundance ratios, following the recent paper by Trager et al., leads to higher mean metallicity and slightly younger age estimates while preserving the metallicity sequence. The [Mg/Fe] ratio is mildly correlated with the central velocity dispersion, and ranges from [Mg/Fe]=0.05 to 0.3 for galaxies with σ>100 km s−1. Under the assumption that there is no age gradient along the index–σ relations, the abundance‐ratio‐corrected Mg–σ,Fe–σ and Hβ–σ relations give consistent estimates of Δ[M/H]/Δ log σ≃0.9±0.1. The slope of the Hβ–σ relation limits a potential age trend as a function of σ to 2–3 Gyr along the sequence.