High-redshift quasar selection from the CFHQSIR survey

Being observed only one billion years after the Big Bang, z ∼ 7 quasars are a unique opportunity for exploring the early Universe. However, only two z ∼ 7 quasars have been discovered in near-infrared surveys: the quasars ULAS J1120+0641 and ULAS J1342+0928 at z = 7.09 and z = 7.54, respectively. The rarity of these distant objects, combined with the difficulty of distinguishing them from the much more numerous population of Galactic low-mass stars, requires using efficient selection procedures. The Canada-France High-z Quasar Survey in the Near Infrared (CFHQSIR) has been carried out to search for z ∼ 7 quasars using near-infrared and optical imaging from the Canada-France Hawaii Telescope (CFHT). Our data consist of ∼130 deg2 of Wide-field Infrared Camera (WIRCam) Y-band images up to a 5σ limit of YAB ∼ 22.4 distributed over the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) Wide fields. After follow-up observations in J band, a first photometric selection based on simple colour criteria led us to identify 36 sources with measured high-redshift quasar colours. However, we expect to detect only ∼2 quasars in the redshift range 6.8 < z < 7.5 down to a rest-frame absolute magnitude of M1450 = −24.6. With the motivation of ranking our high-redshift quasar candidates in the best possible way, we developed an advanced classification method based on Bayesian formalism in which we model the high-redshift quasars and low-mass star populations. The model includes the colour diversity of the two populations and the variation in space density of the low-mass stars with Galactic latitude, and it is combined with our observational data. For each candidate, we compute the probability of being a high-redshift quasar rather than a low-mass star. This results in a refined list of the most promising candidates. Our Bayesian selection procedure has proven to be a powerful technique for identifying the best candidates of any photometrically selected sample of objects, and it is easily extendable to other surveys

The CFHQSIR survey: a Y-band extension of the CFHTLS-Wide survey

International audienceContext. The Canada–France–Hawaii Telescope Legacy Survey (CFHTLS) has been conducted over a 5-yr period at the CFHT with the MegaCam instrument, totaling 450 nights of observations. The Wide Synoptic Survey is one component of the CFHTLS, covering 155 square degrees in four patches of 23 to 65 square degrees through the whole MegaCam filter set (u*, g’, r’, i’, z’) down to i’AB = 24.5.Aims. With the motivation of searching for high-redshift quasars at redshifts above 6.5, we extend the multi-wavelength CFHTLS-Wide data in the Y -band down to magnitudes of ~22.5 for point sources (5σ).Methods. We observed the four CFHTLS-Wide fields (except one quarter of the W3 field) in the Y -band with the Wide-field InfraRed Camera (WIRCam) at the CFHT. Each field was visited twice, at least three weeks apart. Each visit consisted of two dithered exposures. The images are reduced with the Elixir software used for the CFHTLS and modified to account for the properties of near-InfraRed (IR) data. Two series of image stacks are subsequently produced: four-image stacks for each WIRCam pointing, and one-square-degree tiles matched to the format of the CFHTLS data release. Photometric calibration is performed on stars by fitting stellar spectra to their CFHTLS photometric data and extrapolating their Y -band magnitudes.Results. After corrections accounting for correlated noise, we measure a limiting magnitude of YAB ≃ 22.4 for point sources (5σ) in an aperture diameter of 0.′′93, over 130 square degrees. We produce a multi-wavelength catalogue combining the CFHTLS-Wide optical data with our CFHQSIR (Canada–France High-z quasar survey in the near-InfraRed) Y -band data. We derive the Y -band number counts and compare them to the Vista Deep Extragalactic Observations survey (VIDEO). We find that the addition of the CFHQSIR Y -band data to the CFHTLS optical data increases the accuracy of photometric redshifts and reduces the outlier rate from 13.8% to 8.8% in the redshift range 1.05 ≲ z ≲ 1.2

The Impact of Capital on Lending in Economic Downturns and Investor Protection The Case of Large EU Banks

This paper attempts to find out whether better quality of investor protection matters for the effect of capital ratio on loan growth of large EU banks in 1996-2011. We focus on several measures of the quality of investor protection with a proven track record in the banking literature, i.e.: anti-self-dealing index, ex-antecontrol and ex-post-control of anti-self-dealing indices, and creditor protection rights index. Our results show that better investor protection increases the procyclical impact of capital on lending in the sample of banks reporting unconsolidated data. This is consistent with the view that better shareholders rights protection induces bank borrowers to take more loans and to engage in more risk-taking, in particular during economic booms, which results in greater sensitivity of bank lending to capital ratios in economic downturns. The opposite effect is found in the sample of banks reporting consolidated data. This effect is consistent with the view that better minority shareholders protection may reduce risk-taking incentives of large banks and result in better risk management of credit portfolio (and other investments of such banks)