We present discovery imaging and spectroscopy for nine new z ∼ 6 quasars found in the Canada-France Highz Quasar Survey (CFHQS) bringing the total number of CFHQS quasars to 19. By combining the CFHQS with the more luminous SDSS sample we are able to derive the quasar luminosity function from a sample of 40 quasars at redshifts 5.74 < z < 6.42. Our binned luminosity function shows a slightly lower normalisation and flatter slope than found in previous work. The binned data also suggest a break in the luminosity function at M 1450 ≈ −25. A double power law maximum likelihood fit to the data is consistent with the binned results. The luminosity function is strongly constrained (1 σ uncertainty < 0.1 dex) over the range −27.5 < M 1450 < −24.7. The best-fit parameters are Φ(M * 1450 ) = 1.14 × 10 −8 Mpc −3 mag −1 , break magnitude M * 1450 = −25.13 and bright end slope β = −2.81. However the covariance between β and M * 1450 prevents strong constraints being placed on either parameter. For a break magnitude in the range −26 < M * 1450 < −24 we find −3.8 < β < −2.3 at 95% confidence. We calculate the z = 6 quasar intergalactic ionizing flux and show it is between 20 and 100 times lower than that necessary for reionization. Finally, we use the luminosity function to predict how many higher redshift quasars may be discovered in future near-IR imaging surveys.

We present discovery observations of a quasar in the Canada-France High-z Quasar Survey (CFHQS) at redshift z = 6.44. We also use near-IR spectroscopy of nine CFHQS quasars at z ∼ 6 to determine black hole masses. These are compared with similar estimates for more luminous Sloan Digital Sky Survey (SDSS) quasars to investigate the relationship between black hole mass and quasar luminosity. We find a strong correlation between Mg ii FWHM and UV luminosity and that most quasars at this early epoch are accreting close to the Eddington limit. Thus these quasars appear to be in an early stage of their life cycle where they are building up their black hole mass exponentially. Combining these results with the quasar luminosity function, we derive the black hole mass function at z = 6. Our black hole mass function is ∼ 10 4 times lower than at z = 0 and substantially below estimates from previous studies. The main uncertainties which could increase the black hole mass function are a larger population of obscured quasars at high-redshift than is observed at low-redshift and/or a low quasar duty cycle at z = 6. In comparison, the global stellar mass function is only ∼ 10 2 times lower at z = 6 than at z = 0. The difference between the black hole and stellar mass function evolution is due to either rapid early star formation which is not limited by radiation pressure as is the case for black hole growth or inefficient black hole seeding. Our work predicts that the black hole mass -stellar mass relation for a volume-limited sample of galaxies declines rapidly at very high redshift. This is in contrast to the observed increase at 4 < z < 6 from the local relation if one just studies the most massive black holes.

The Canada-France High-z Quasar Survey (CFHQS) is an optical survey designed to locate quasars during the epoch of reionization. In this paper we present the discovery of the first four CFHQS quasars at redshifts greater than 6, including the most distant known quasar, CFHQS J2329À0301 at z ¼ 6:43. We describe the observational method used to identify the quasars and present optical, infrared, and millimeter photometry and optical and near-infrared spectroscopy. We investigate the dust properties of these quasars, finding an unusual dust extinction curve for one quasar and a high far-infrared luminosity due to dust emission for another. The mean millimeter continuum flux for CFHQS quasars is substantially lower than that for SDSS quasars at the same redshift, likely due to a correlation with quasar UV luminosity. For two quasars with sufficiently high signal-to-noise ratio optical spectra, we use the spectra to investigate the ionization state of hydrogen at z > 5. For CFHQS J1509À1749 at z ¼ 6:12 we find significant evolution ( beyond a simple extrapolation of lower redshift data) in the Gunn-Peterson optical depth at z > 5:4. The line of sight to this quasar has one of the highest known optical depths at z % 5:8. An analysis of the sizes of the highly ionized near-zones in the spectra of two quasars at z ¼ 6:12 and 6.43 suggest that the intergalactic medium surrounding these quasars was substantially ionized before these quasars turned on. Together, these observations point toward an extended reionization process, but we caution that cosmic variance is still a major limitation in z > 6 quasar observations.

We present the results of photometric surveys for stellar rotation in the Hyades and in Praesepe, using data obtained as part of the SuperWASP exoplanetary transit‐search programme. We determined accurate rotation periods for more than 120 sources whose cluster membership was confirmed by common proper motion and colour–magnitude fits to the clusters’ isochrones. This allowed us to determine the effect of magnetic braking on a wide range of spectral types for expected ages of ∼600 Myr for the Hyades and Praesepe. Both clusters show a tight and nearly linear relation between J−Ks colour and rotation period in the F, G and K spectral range. This confirms that loss of angular momentum was significant enough that stars with strongly different initial rotation rates have converged to the same rotation period for a given mass, by the ages of Hyades and Praesepe. In the case of the Hyades, our colour–period sequence extends well into the M dwarf regime and shows a steep increase in the scatter of the colour–period relation, with identification of numerous rapid rotators from ∼0.5 M⊙ down to the lowest masses probed by our survey (∼0.25 M⊙). This provides crucial constraints on the rotational braking time‐scales and further clears the way to use gyrochronology as an accurate age measurement tool for main‐sequence stars.

Direct imaging has just started the inventory of the population of gas giant planets on wideorbits around young stars in the solar neighborhood. Following this approach, we carried out a deep imaging survey in the near-infrared using VLT/NaCo to search for substellar companions. We report here the discovery in L ' (3.8 µm) images of a probable companion orbiting at 56 AU the young (10 − 17 Myr), dusty, and early-type (A8) star HD 95086. This discovery is based on observations with more than a year-time-lapse. Our first epoch clearly revealed the source at ≃ 10 σ while our second epoch lacked good observing conditions hence yielding a ≃ 3 σ detection. Various tests were thus made to rule out possible artifacts. This recovery is consistent with the signal at the first epoch but requires cleaner confirmation. Nevertheless, our astrometric precision suggests the companion to be comoving with the star, with a 3 σ confidence level. The planetary nature of the source is reinforced by a non-detection in Ks-band (2.18 µm) images according to its possible extremely red Ks -L ' color. Conversely, background contamination is rejected with good confidence level. The luminosity yields a predicted mass of about 4 − 5 M Jup (at 10 − 17 Myr) using "hot-start" evolutionary models, making HD 95086 b the exoplanet with the lowest mass ever imaged around a star.