منابع مشابه
Modeling the Counts of Faint Radio Loud Quasars: Constraints on the Supermassive Black Hole Population and Predictions for High Redshift
We use a physically motivated semi–analytic model, based on the mass function of dark matter halos, to predict the number of radio–loud quasars as a function of redshift and luminosity. Simple models in which the central BH mass scales with the velocity dispersion of its host halo as Mbh ∝ σ5 halo have been previously found to be consistent with a number of observations, including the optical a...
متن کاملOn the Selection of High-z Quasars Using LOFAR Observations
We present a method to identify candidate quasars which combines optical/infrared color selection with radio detections from the Low Frequency ARray (LOFAR) at 150 MHz. We apply this method in a region of 9 square degrees located in the Boötes field, with a wealth of multi-wavelength data. Our LOFAR imaging in the central region reaches a rms noise of ∼ 50μJy with a resolution of 5. This is so ...
متن کاملReverberation Mapping of High-z, High-Luminosity Quasars
We present Reverberation Mapping results after monitoring a sample of 17 high-z, high-luminosity quasars for more than 10 years using photometric and spectroscopic capabilities. Continuum and line emission flux variability is observed in all quasars. Using cross-correlation analysis we successfully determine lags between the variations in the continuum and broad emission lines for several sourc...
متن کاملFaint galaxies around quasars at z = 1 and gravitational lensing of distant objects
Very deep imaging data of three optically luminous radio-loud quasars with redshifts between z = 0.9 and z = 1.36 are presented. The data are complete for galaxies down to R = 26. There is no evidence for excess numbers of galaxies around the quasars; foreground galaxy clusters are excluded by the data aswell as clusters with richness classes greater than 1 associated with the quasars.Wefind cl...
متن کاملConstraints on Reionization and Source Properties from the Absorption Spectra of Z > 6.2 Quasars
We make use of hydrodynamical simulations of the intergalactic medium (IGM) to create model quasar absorption spectra. We compare these model spectra with the observed Keck spectra of three z > 6.2 quasars with full Gunn-Peterson troughs: SDSS J1148+5251 (z = 6.42), SDSS J1030+0524 (z = 6.28), and SDSS J1623+3112 (z = 6.22). We fit the probability density distributions (PDFs) of the observed Ly...
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ژورنال
عنوان ژورنال: Proceedings of the International Astronomical Union
سال: 2006
ISSN: 1743-9213,1743-9221
DOI: 10.1017/s1743921307010447