Related papers: Strong X-ray Absorption in a BALQSO: PHL5200
Recent results from the ROSAT All-Sky Survey (RASS) have shown that broad absorption line (BAL) QSOs are either highly absorbed or underluminous in the soft X-ray bandpass. Here, we extend this work by analyzing all known bona fide BALQSOs…
Most X-ray studies of BALQSOs found significant (N_H~10^{22-24} cm^{-2}) intrinsic column densities of gas absorbing an underlying typical power-law continuum emission, in agreement with expectations from radiatively driven accretion disk…
This paper discusses the detection of P V 1118,1128 and other broad absorption lines (BALs) in archival HST spectra of the low-redshift BALQSO, PG 1254+047. The P V identification is secured by excellent redshift and profile coincidences…
We present a deep ($\sim$85 ksec) ASCA observation of the prototype Broad Absorption Line Quasar (BALQSO) PHL 5200. This is the best X-ray spectrum of a BALQSO yet. We find that (1) the source is not intrinsically X-ray weak, (2) the line…
We present \textit{Chandra} observations of the radio-quiet Broad Absorption Line (BAL) QSO PG 1254+047. We find that it is a weak X-ray source, with a total of $44\pm 7$ photons measured in 36 ksec across the observed energy range $0.7 -…
Several studies have shown that the column densities inferred from broad absorption lines (BALs) require extremely high metallicities and phosphorus overabundances -- apparently in conflict with other abundance diagnostics. Here I use HST…
We present the analysis and interpretation of a sample of eight ASCA observations of Broad Absorption Line Quasi-Stellar Objects (BALQSOs). This is the first moderate-sized sample of sensitive BALQSO observations above 2 keV, and the…
We present a deep ASCA observation of a Broad Absorption Line Quasar (BALQSO) PG0946+301. The source was clearly detected in one of the gas imaging spectrometers, but not in any other detector. If BALQSOs have intrinsic X-ray spectra…
Recent results from the ROSAT All Sky Survey, and from deep ROSAT pointings reveal that broad absorption line quasars (BALQSOs) are weak in the soft X-ray bandpass (with optical-to-X-ray spectral slope alpha_{ox}>1.8) in comparison to QSOs…
In this article, the hydrogen column densities derived from X-ray observations of type II (hidden) quasars and broad absorption line quasars (BALQSOs) are compared. These column densities represent the amount of absorbing material between…
We have carried out a survey with the Chandra X-ray Observatory of a sample of 10 optically bright broad absorption line (BAL) QSOs. Eight out of ten sources are detected. The 6 brightest X-ray sources have only high ionization BALs…
We present the results from XMM-Newton observations of the highly optically polarized broad absorption line quasar (BALQSO) CSO 755. By analyzing its X-ray spectrum with a total of ~3000 photons we find that this source has an X-ray…
We report the discovery of significant linear polarization (p > 1%) in the hyperluminous z=3.87 BALQSO APM~08279+5255. The polarization spectrum is complex, with properties similar to those of other, lower redshift but more highly polarized…
It is been known for more than a decade that BALQSOs (broad absorption line quasars) are highly attenuated in the X-ray regime compared to other quasars, especially in the soft band ($< $ 1 keV). Using X-ray selection techniques we have…
We are involved in a program to derive properties of broad absorption line (BAL) winds in quasars using combined UV and X-ray observations. A major obstacle is large uncertainties in the derived BAL column densities because of partial…
We study a sample of six X-ray selected broad absorption line (BAL) quasi-stellar objects (QSOs) from the XMM-Newton Wide Angle Survey. All six objects are classified as BALQSOs using the classic balnicity index, and together they form the…
For the population of QSOs with broad ultraviolet absorption lines, we are just beginning to accumulate X-ray observations with enough counts for spectral analysis at CCD resolution. From a sample of eight QSOs [including four Broad…
There is growing evidence of a higher intrinsic fraction of broad absorption line quasars (BALQSOs) than that obtained in optical surveys, on which most previous X-ray studies of BALQSOs have focused. Here we present Chandra observations of…
We present Chandra observations of two radio-quiet QSOs, PG 2302+029 and PG 1254+047. PG 2302+029 has an ultra high-velocity UV absorption system -56,000 km/s, while PG 1254+047 is a Broad Absorption Line (BAL) QSO with detached troughs.…
Recent observations of Broad Absorption Line (BAL) quasars demonstrated that the soft X-ray emission of these objects is extremely weak and convincing evidence for very strong absorption by a high column density (~ 10^23.5 cm^-2) was…