ﻻ يوجد ملخص باللغة العربية
We present new observations of the highest-redshift quasar known, ULAS J1120+0641, redshift $z=7.084$, obtained in the optical, at near-, mid-, and far-infrared wavelengths, and in the sub-mm. We combine these results with published X-ray and radio observations to create the multiwavelength spectral energy distribution (SED), with the goals of measuring the bolometric luminosity $L_{rm bol}$, and quantifying the respective contributions from the AGN and star formation. We find three components are needed to fit the data over the wavelength range $0.12-1000,mu$m: the unobscured quasar accretion disk and broad-line region, a dusty clumpy AGN torus, and a cool 47K modified black body to characterise star formation. Despite the low signal-to-noise ratio of the new long-wavelength data, the normalisation of any dusty torus model is constrained within $pm40%$. We measure a bolometric luminosity $L_{rm bol}=2.6pm0.6times10^{47},$erg$,$s$^{-1}=6.7 pm 1.6times10^{13}L_{odot}$, to which the three components contribute $31%,32%,3%$, respectively, with the remainder provided by the extreme UV $<0.12,mu$m. We tabulate the best-fit model SED. We use local scaling relations to estimate a star formation rate (SFR) in the range $60-270,{rm M}_odot$/yr from the [C$,{scriptsize rm II}$] line luminosity and the $158,mu$m continuum luminosity. An analysis of the equivalent widths of the [C$,{scriptsize rm II}$] line in a sample of $z>5.7$ quasars suggests that these indicators are promising tools for estimating the SFR in high-redshift quasars in general. At the time observed the black hole was growing in mass more than 100 times faster than the stellar bulge, relative to the mass ratio measured in the local universe, i.e. compared to ${M_{rm BH}}/{M_{rm bulge}} simeq 1.4times10^{-3}$, for ULAS J1120+0641 we measure ${dot{M}_{rm BH}}/{dot{M}_{rm bulge}} simeq 0.2$.
We present X-ray imaging and spectroscopy of the redshift z=7.084 radio-quiet quasar ULAS J112001.48+064124.3 obtained with Chandra and XMM-Newton. The quasar is detected as a point source with both observatories. The Chandra observation provides a p
We present optical and near-infrared imaging of the field of the z=7.0842 quasar ULAS J112001.48+064124.3 taken with the Hubble Space Telescope. We use these data to search for galaxies that may be physically associated with the quasar, using the Lym
The quasar ULAS J1120+0641 at redshift z=7.085 has a highly ionised near zone which is smaller than those around quasars of similar luminosity at z~6. The spectrum also exhibits evidence for a damping wing extending redward of the systemic Lya redshi
We present a search for metal absorption line systems at the highest redshifts to date using a deep (30h) VLT/X-Shooter spectrum of the z = 7.084 quasi-stellar object (QSO) ULAS J1120+0641. We detect seven intervening systems at z > 5.5, with the hig
We perform a spectral analysis of a sample of 11 medium redshift (1.5 < z < 2.2) quasars. Our sample all have optical spectra from the SDSS, infrared spectra from GNIRS and TSPEC, and X-ray spectra from XMM-Newton. We first analyse the Balmer broad e