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The MiMeS (Magnetism in Massive Stars) project is a large-scale, high-resolution, sensitive spectropolarimetric investigation of the magnetic properties of O- and early B-type stars. Initiated in 2008 and completed in 2013, the project was supported by three Large Program allocations, as well as various programmes initiated by independent principal investigators, and archival resources. Ultimately, over 4800 circularly polarized spectra of 560 O and B stars were collected with the instruments ESPaDOnS (Echelle SpectroPolarimetric Device for the Observation of Stars) at the Canada-France-Hawaii Telescope, Narval at the T'elescope Bernard Lyot and HARPSpol at the European Southern Observatory La Silla 3.6 m telescope, making MiMeS by far the largest systematic investigation of massive star magnetism ever undertaken. In this paper, the first in a series reporting the general results of the survey, we introduce the scientific motivation and goals, describe the sample of targets, review the instrumentation and observational techniques used, explain the exposure time calculation designed to provide sensitivity to surface dipole fields above approximately 100 G, discuss the polarimetric performance, stability and uncertainty of the instrumentation, and summarize the previous and forthcoming publications. [ABSTRACT FROM AUTHOR]

Aims. We present an improved method for automated stellar variability classification, using fundamental parameters derived from high resolution spectra, with the goal to improve the variability classification obtained using information derived from CoRoT light curves only. Although we focus on Giraffe spectra and CoRoT light curves in this work, the methods are much more widely applicable. Methods. In order to improve the variability classification obtained from the photometric time series, only rough estimates of the stellar physical parameters (Teeff and log (g)) are needed because most variability types that overlap in the space of time series parameters, are well separated in the space of physical parameters (e.g.γ Dor/SPB or δ Sct/β Cep). In this work, several state-of-the-art machine learning techniques are combined to estimate these fundamental parameters from high resolution Giraffe spectra. Next, these parameters are used in a multi-stage Gaussian-Mixture classifier to perform an improved supervised variability classification of CoRoT light curves. The variability classifier can be used independently of the regression module that estimates the physical parameters, so that non-spectroscopic estimates derived e.g. from photometric colour indices can be used instead. Results. Teff and log (g) are derived from Giraffe spectra, for 6832 CoRoT targets. The use of those parameters in addition to information extracted from the CoRoT light curves, significantly improves the results of our previous automated stellar variability classification. Several new pulsating stars are identified with high confidence levels, including hot pulsators such as SPB and β Cep, and several γDor-δ Sct hybrids. From our samples of new Dor and δ Sct stars, we find strong indications that the instability domains for both types of pulsators are larger than previously thought. [ABSTRACT FROM AUTHOR]

This work continues our efforts to calibrate model surface brightness fluctuation luminosities for the study of unresolved stellar populations, through a comparison with the data of Magellanic Cloud star clusters. We present here the relation between absolute Ks-band fluctuation magnitude and ( V– I) integrated colour, using data from the Two-Micron All-Sky Survey (2MASS) and the Deep Near-Infrared Southern Sky Survey (DENIS), and from the literature. We compare the star cluster sample with the sample of early-type galaxies and spiral bulges studied by Liu et al. We find that intermediate-age to old star clusters lie along a linear correlation with the same slope, within the errors, of that defined by the galaxies in the versus ( V– I) diagram. While the calibration by Liu et al. was determined in the colour range , ours holds in the interval . This implies, according to Bruzual–Charlot and Mouhcine–Lançon models, that the star clusters and the latest star formation bursts in the galaxies and bulges constitute an age sequence. At the same time, a slight offset between the galaxies and the star clusters [the latter are ∼0.7 mag fainter than the former at a given value of ( V– I)], caused by the difference in metallicity of roughly a factor of 2, confirms that the versus ( V– I) plane may contribute to break the age–metallicity degeneracy in intermediate-age and old stellar populations. The confrontation between models and galaxy data also suggests that galaxies with Ks fluctuation magnitudes that are brighter than predicted, given their ( V– I) colour, might be explained in part by longer lifetimes of thermally pulsing asymptotic giant branch stars. A preliminary comparison between the H 2MASS data of the Magellanic star clusters and the sample of 47 early-type galaxies and spiral bulges observed by Jensen et al. through the F160 W Hubble Space Telescope filter leads to the same basic conclusions: galaxies and star clusters lie along correlations with the same slope, and there is a slight offset between the star cluster sample and the galaxies, caused by their different metallicities. Magellanic star clusters are single populations, while galaxies are composite stellar systems; moreover, the objects analysed live in different environments. Therefore, our findings mean that the relationship between fluctuation magnitudes in the near-infrared, and ( V– I) might be a fairly robust tool for the study of stellar population ages and metallicities, could provide additional constraints on star formation histories, and aid in the calibration of near-infrared surface brightness fluctuations for cosmological distance measurements. [ABSTRACT FROM AUTHOR]