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The NASA Kepler mission has revolutionised time-domain astronomy and has massively expanded the number of known extrasolar planets. However, the effect of wide multiplicity on exoplanet occurrence has not been tested with this dataset. We present a sample of 401 wide multiple systems containing at least one Kepler target star. Our method uses Pan-STARRS1 and archival data to produce an accurate proper motion catalogue of the Kepler field. Combined with Pan-STARRS1 SED fits and archival proper motions for bright stars, we use a newly developed probabilistic algorithm to identify likely wide binary pairs which are not chance associations. As by-products of this we present stellar SED templates in the Pan-STARRS1 photometric system and conversions from this system to Kepler magnitudes. We find that Kepler target stars in our binary sample with separations above 6 arcseconds are no more or less likely to be identified as confirmed or candidate planet hosts than a weighted comparison sample of Kepler targets of similar brightness and spectral type. Therefore we find no evidence that binaries with projected separations greater than 3,000AU affect the occurrence rate of planets with P, 15 figures, 6 tables, MNRAS accepted, Tables 1 and 4 available from http://www.star.herts.ac.uk/~ndeacon/PS1Kepler.html . Replacement updates Figure 11 and the text referring to it

Recent calculations using non-linear relativistic cosmological perturbation theory show biases in the mean luminosity distance and distance modulus at low redshift. We show that these effects may be understood very simply as a non-relativistic, and purely kinematic, Malmquist-like bias, and we describe how the effect changes if one averages over sources that are limited by apparent magnitude. This effect is essentially identical to the distance bias from small-scale random velocities that has previously been considered by astronomers, though we find that the standard formula overestimates the homogeneous bias by a factor 2.

In the conventional framework for cosmological dynamics the scale factor $a(t)$ is assumed to obey the `background' Friedmann equation for a perfectly homogeneous universe while particles move according to equations of motions driven by the gravity of the density fluctuations. It has recently been suggested that the emergence of structure modifies the evolution of $a(t)$ via Newtonian (or `kinematic') backreaction and that this may avoid the need for dark energy. Here we point out that the conventional system of equations is exact in Newtonian gravity and there is no approximation in the use of the homogeneous universe equation for $a(t)$. The recently proposed modification of Racz et al.\ (2017) does not reduce to Newtonian gravity in the limit of low velocities. We discuss the relation of this to the `generalised Friedmann equation' of Buchert and Ehlers. These are quite different things; their formula describes individual regions and is obtained under the restrictive assumption that the matter behaves like a pressure-free fluid whereas our result is exact for collisionless dynamics and is an auxiliary relation appearing in the structure equations. We use the symmetry of the general velocity autocorrelation function to show how Buchert's $\cal Q$ tends very rapidly to zero for large volume and that this does not simply arise `by construction' through the adoption of periodic boundary conditions as has been claimed. We conclude that, to the extent that Newtonian gravity accurately describes the low-$z$ universe, there is no backreaction of structure on $a(t)$ and that the need for dark energy cannot be avoided in this way., Comment: 6 pages, 0 figures. Substantially revised in response to reviewer's suggestions

In homogeneous cosmological models the wavelength $\lambda$ of a photon exchanged between two fundamental observers changes in proportion to expansion of the space $D$ between them, so $\Delta\log(\lambda / D) = 0$. This is exactly the same as for a pair of observers receding from each other in flat space-time where the effect is purely kinematic. The interpretation of this has been the subject of considerable debate, and it has been suggested that all redshifts are a relative velocity effect, raising the question of whether the wavelength always stretches in proportion to the emitter-receiver separation. Here we show that, for low redshift at least, $\Delta\log(\lambda / D)$ vanishes for a photon exchanged between any two freely-falling observers in a spatially constant tidal field, because such a field stretches wavelengths and the space between the observers identically. But in general there is a non-kinematic, and essentially gravitational, component of the redshift that is given by a weighted average of the gradient of the tidal field along the photon path. While the redshift can always be formally expressed using the Doppler formula, in situations where the gravitational redshift dominates, the `relative velocity' is typically quite different from the rate of change of $D$ and it is misleading to think of the redshift as being a velocity or `kinematic' effect., Comment: 11 pages, 5 figures, original submission to MNRAS 10/29/2013

The Pan-STARRS1 survey is acquiring multi-epoch imaging in 5 bands (grizy) over the entire sky north of declination -30deg (the $3\pi$ survey). In July 2011 a test area of about 70 sq.deg. was observed to the expected final depth of the main survey. In this, the first of a series of papers targetting the galaxy count and clustering properties of the combined multi-epoch test area data, we present a detailed investigation into the depth of the survey and the reliability of the Pan-STARRS1 analysis software. We show that the Pan-STARRS1 reduction software can recover the properties of fake sources, and show good agreement between the magnitudes measured by Pan-STARRS1 and those from Sloan Digital Sky Survey. We also examine the number of false detections apparent in the Pan-STARRS1 data. Our comparisons show that the test area survey is somewhat deeper than the Sloan Digital Sky Survey in all bands, and, in particular, the z band approaches the depth of the stacked Sloan Stripe 82 data., Comment: 17 pages, 24 figures. Published by MNRAS, published version available at: http://mnras.oxfordjournals.org/content/435/3/1825

We describe the construction of the QDOT survey, which is publicly available from an anonymous FTP account. The catalogue consists of infrared properties and redshifts of an all-sky sample of 2387 IRAS galaxies brighter than the IRAS PSC 60-μm completeness limit (S60>0.6 Jy), sparsely sampled at a rate of one-in-six. At |b|>10°, after removing a small number of Galactic sources, the redshift completeness is better than 98 per cent (2086/2127). New redshifts for 1401 IRAS sources were obtained to complete the catalogue; the measurement and reduction of these are described, and the new redshifts tabulated here. We also tabulate all sources at |b|>10° with no redshift so far, and sources with conflicting alternative redshifts either from our own work, or from published velocities. A list of 95 ultraluminous galaxies (i.e. with L60 μm>1012 L⊙) is also provided. Of these, ∼20 per cent are AGN of some kind; the broad-line objects typically show strong Fe ii emission. Since the publication of the first QDOT papers, there have been several hundred velocity changes: some velocities are new, some QDOT velocities have been replaced by more accurate values, and some errors have been corrected. We also present a new analysis of the accuracy and linearity of IRAS 60-μm fluxes. We find that the flux uncertainties are well described by a combination of 0.05-Jy fixed size uncertainty and 8 per cent fractional uncertainty. This is not enough to cause the large Malmquist-type errors in the rate of evolution postulated by Fisher et al. We do, however, find marginal evidence for non-linearity in the PSC 60-μm flux scale, in the sense that faint sources may have fluxes overestimated by about 5 per cent compared with bright sources. We update some of the previous scientific analyses to assess the changes. The main new results are as follows. (1) The luminosity function is very well determined overall but is uncertain by a factor of several at the very highest luminosities (L60 μm>5×1012 L⊙), as this is where the remaining unidentified objects are almost certainly concentrated. (2) The best-fitting rate of evolution is somewhat lower than our previous estimate; expressed as pure density evolution with density varying as (1+z)p, we find p=5.6±2.3. Making a rough correction for the possible (but very uncertain) non-linearity of fluxes, we find p=4.5±2.3. (3) The dipole amplitude decreases a little, and the implied value of the density parameter, assuming that IRAS galaxies trace the mass, is Ω=0.9(+0.45, −0.25). (4) Finally, the estimate of density variance on large scales changes negligibly, still indicating a significant discrepancy from the predictions of simple cold dark matter cosmogonies.

Using the QDOT IRAS galaxy redshift survey, a smoothed density field is constructed, corrected for peculiar velocity distortion, of a region of the local universe out to ∼ 150 h −1 Mpc. Predicted peculiar velocities are calculated from this density field, assuming gravitational instability theory, and compared to observed velocities derived from Tully-Fisher and D n −σ techniques. A good correlation is seen. If IRAS galaxies trace the mass on large scales then the universe must have a density very close to the critical value.

Une etude d'un echantillon de 2818 galaxies IRAS est realisee. La fonction de luminosite a 60 μm independante des variations de flux, et la distribution de densite radiale, independante de la fonction de luminosite, sont determinees avec une methode du maximum de vraisemblance

L'anisotropie dipolaire du ciel optique et IRAS et les solutions du champ de vitesses particulieres sont comparees aux predictions du modele de la matiere sombre froide. Les estimations en vraisemblance maximale du parametre de normalisation defini comme la valeur quadratique moyenne de la fluctuation de masse dans des spheres 8 Mpc•h −1 , et le parametre de biais defini comme le rapport de la fluctuation dans les denombrements des galaxies a la fluctuation de masse sont obtenus. Les predictions du modele sont en accord avec les observations; la statistique khi deux est parfaitement acceptable. Les donnees sont egalement compatibles avec le modele d'isocourbure minimale baryonique. Une version amelioree du test de Gott est developpee et appliquee en utilisant les correlations entre un nombre de dipoles angulaires et les solutions d'ecoulement en masse

A theory is presented describing linear perturbations of an expanding universe containing multiple, independently perturbed, collisionless, gravitationally coupled constituents. Solutions are found in the limit where one initially unperturbed component dominates the total density. The theory is applied to perturbations generated by a nongravitational process in one or more of the light components, as would occur in explosive or radiation-pressure-instability theories of galaxy formation. The apparent dynamical density parameter and correlations between density and velocity amplitude for various populations, are evaluated as a function of cosmic scale factor.

Les proprietes d'agencement des condensations de matiere sombre produites dans le scenario de la matiere sombre froide sont calculees et les resultats sont appliques aux galaxies et autres objets astronomiques qui pourraient etre identifies avec quelque sous-ensemble de ces halos sombres

L'examen d'un echantillon de galaxies IRAS a permis de decouvrir un quasar tres inhabituel (source IRAS 07598+6508) dont le spectre optique est domine par une emission Fe II extremement forte. Il semble exister une petite classe d'emetteurs Fe II super-forts. Les modeles standards de photo-ionisation ne permettent pas d'expliquer les proprietes extremes de ces objets

Calcul des fluctuations en temperature dans le rayonnement de fond microonde par le gaz chaud confine par les puits de potentiel de matiere sombre a travers l'effet Sunyaev-Zel'dovich. On montre que les fluctuations devraient etre dominees par les amas massifs rares a redshifts moderes. Les fluctuations (ΔT/T) rms sont calculees comme fonctions de l'echelle angulaire et l'accroissement du a l'agencement des amas est quantifie. Des cartes simulees du ciel, montrant le caractere non Gaussien des fluctuations sont produites et la fonction de distribution pour les fluctuations en est deduite