Related papers: The discovery of a high redshift type 2 QSO
Deep hard X-ray and near infrared observations of a type-2 radio-quiet QSO candidate at z=0.9, AXJ08494+4454, are reported. The 0.5-10keV Chandra X-ray Observatory spectrum of AXJ08494+4454 is hard, and is explained well with a power-law…
We present XMM-Newton data centered on one of the MUNICS Near Infrared Cluster Survey fields (S2F1) and we discuss the X-ray properties of the 6 X-ray emitting EROs found. For one of them we have already obtained the redshift using…
Intrinsic emission and absorption lines of QSOs provide several independent probes of the metal abundances in QSO environments. They indicate that the metallicities are typically solar or higher out to redshifts z > 4. These results support…
We report the discovery of a galaxy at a redshift z = 6.17 identified from deep narrow band imaging and spectroscopic follow-up in one of the CFHT-VIRMOS deep survey fields at 0226-04. In addition to the existing deep BVRI images of this…
We report on the analysis of a BeppoSAX observation of IRAS 13197-1627. The complexity of the broad band (0.3-100 keV) spectrum of the source prevents us from selecting from two possible best-fit models, i.e. one based on a partial covering…
We present an analysis of X-ray variability in a sample of 156 radio quiet quasars taken from the ROSAT archive, covering a redshift range 0.1 < z < 4.1. A maximum likelihood method is used to constrain the amplitude of variability in these…
We describe in this paper the ROSAT Ultra Deep Survey (UDS), an extension of the ROSAT Deep Survey (RDS) in the Lockman Hole. The UDS reaches a flux level of 1.2 x 10E-15 erg/cm2/s in 0.5-2.0 keV energy band, a level ~4.6 times fainter than…
In this letter we report the detection of an extremely strong X-ray emission line in the 940ks chandra ACIS-I spectrum of CXO CDFS J033225.3-274219. The source was identified as a Type1 AGN at redshift of z = 1.617, with 2.0 -- 10.0 keV…
Astronomical or cosmological redshifts are an observable property of extragalactic objects and have historically been wholly attributed to the recessional velocity of that object. The question of other, or intrinsic, components of the…
We announce the discovery of an extended emission line region associated with a high redshift type-2 QSO. The halo, which was discovered in our new wide-field narrow-band survey, resides at z = 2.85 in the Spitzer First Look Survey region…
Although about a dozen high redshift (z larger than 2) starburst galaxies have been recently detected in the CO lines, spectroscopic detections of molecular gas of very young galaxies are still very difficult. The CO lines are usually…
We discuss broad- and narrow-band imaging of 7 arcmin fields of 14 QSOs with redshift ~1.1. The narrow-band filters were chosen to detect redshifted [O II] 3727A, and the broad bands are R and I, which correspond to rest wavelengths…
We announce the detection of correlations on angular scales of $\ga10'$ between optically bright, high-redshift, radio-loud QSOs with diffuse X-ray emission seen by ROSAT in the {\it All-Sky Survey}. These correlations reach significance…
We report the serendipitous discovery of two objects close in projection with fairly strong emission lines at long wavelength (~9190 A). One (A) seems not to be hosted by any galaxy brighter than V(555)=27.5, or I(814)=26.7 (Vega-based…
We present X-shooter at the Vewry Large Telescope observations of a sample of 10 luminous, X-ray obscured QSOs at z$\sim1.5$ from the XMM-COSMOS survey, expected to be caught in the transitioning phase from starburst to active galactic…
We present results of optical identification of the ASCA Large Sky Survey. X-ray sources which have hard X-ray spectra were identified with type-2 AGN at redshifts smaller than 0.5. It is supported that the absorbed X-ray spectrum of type-2…
A database of radio-quiet quasars detected with ROSAT is presented containing 846 quasars seen in the All-Sky Survey and/or in pointed PSPC observations. About 70% of the objects have been detected in X-rays for the first time. We present…
In contradiction to the simple AGN unification schemes, there exists a significant population of broad line, z~2 QSOs which have heavily absorbed X-ray spectra. These objects have luminosities and redshifts characteristic of the sources…
We aim to understand the multi-wavelength properties of 2XMM J123204+215255, the source with the most extreme X-ray-to-optical flux ratio amongst a sample of bright X-ray selected EXOs drawn from a cross-correlation of the 2XMMp catalogue…
Aims: The determination of elusive redshifts of bright BL Lac objects Methods: We use the capabilities of newly available spectrograph X-Shooter at European Southern Observatory (ESO) Very Large Telescope, that combines high resolution and…