We have made progress in the areas related to the propulsion and confinement of gas responsible for broad absorption troughts in QSOs: Radiative Acceleration in BALQSOs; The 'Ghost' of Lyman (alpha); and Magnetic Confinement of Absorbing Gas.

The controversy over whether the absorption spectrum in QSOs is intrinsic or extrinsic is approached

Here we give a brief overview of some investigations of the gravitational microlensing influence on broad absorption spectral lines of lensed QSOs. Especially, we consider the microlensing influence on the Fe K? broad absorption lines using a model of an accretion disk covered by an ...

Studies of QSO absorption lines can be used to discover superclusters of metal-line systems (thought to be associated with galaxies) at large redshift, analogous to the absorbers found in the field surrounding the southern pair Tol 1037/1038. The unique ability of QSO absorption lines to reveal ...

Studies of QSO absorption lines can be used to discover 'superclusters' of metal-line systems (thought to be associated with galaxies) at large redshift, analogous to the absorbers found in the field surrounding the southern pair Tol 1037/1038. The unique ability of QSO absorption lines to ...

Slit spectrophotometry in the 305-855-nm range of 25 QSO candidates identified by slitless spectroscopy in two 1-deg-sq fields (one centered on Abell 2151 and one in a blank region) near the Hercules cluster of galaxies, obtained using image-dissector scanners on the 3-m Lick Observatory and 4-m KPNO telescopes at resolution 5-20 A during 1976-1979, are reported. The data are presented in tables ...

There is a variety of optical evidence for some unification of different types of active galactic nuclei and quasi-stellar objects (QSOs). The case is very strong for the unification of at least some Seyfert galaxies, where polarization data show that the type assigned to the Seyfert galaxy must depend on viewing direction. It has been proposed that Fanaroff-Riley type 2 (FR2) ...

Broad absorption line quasars (BALQSOs) have proven to be elusive soft X-ray sources. Their highly ionized, high column density clouds flow out from the nucleus at 0.1c. On the other hand, the optical/UV emission line spectra of BAL and non-BAL QSOs are quite similar, suggesting similar intrinsic continua. ...

We present the results of a search for metal absorption lines in the spectra of background QSOs whose sight lines pass close to foreground QSOs. We detect Mg II ??2796, 2803 absorption in Sloan Digital Sky Survey (SDSS) spectra of four z>1.5 QSOs ...

Broad Absorption Line QSOs are notoriously faint X-ray sources, and we are just beginning to accumulate data with enough counts for spectral analysis. From our observations, general patterns are emerging: the X-ray continua are typical of normal QSOs, and the signatures of a significant column density of complex ...

Two different interpretations of the phenomenon of broad absorption line (BAL) QSOs are presented and a resolution is suggested. One interpretation is that the BAL clouds cover most of the sky as viewed from the quasar; this implies that BALQSOs are an usual subset of the general class of QSOs. The other ...

Recent results from the ROSAT All-Sky Survey 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 BAL QSOs observed within the inner 20' of the ROSAT Position Sensitive Proportional Counter. ...

(blueshifted) Fe-K absorption lines from highly ionized Fe in some QSOs. (Pounds , Reeves et al. 2003..). " PG 1211+143: v~ 24000 km/s ...

We propose to obtain high resolution, high signal-to-noise observations of QSOs behind the Large Magellanic Clouds. These QSOs are situated beyond the star forming disk of the galaxy, giving us the opportunity to study the distribution of metals and energy in regions lacking significant star formation. In particular, we will derive the metallicities and ...

Resonance-line formation in QSOs with broad absorption lines is considered. An axisymmetric decelerated-outflow model, with the density of scattering atoms highest in the equatorial plane and lowest toward the poles, can yield line profiles fitting those typified both by PHL 5200 (abrupt ...

There is a variety of optical evidence for some unification of different types of active galactic nuclei and quasi-stellar objects (QSOs). The case is very strong for the unification of at least some Seyfert galaxies, where polarization data show that the type assigned to the Seyfert galaxy must depend on viewing direction. It has been proposed that Fanaroff-Riley type 2 (FR2) ...

There exists a significant population of broad line, z~2 QSOs which have heavily absorbed X-ray spectra. Follow up observations in the submillimetre show that these QSOs are embedded in ultraluminous starburst galaxies, unlike most unabsorbed QSOs at the same redshifts and luminosities. Here we present X-ray ...

We present the results of X-ray spectral analysis of two mini-BAL QSOs, PG 1126-041 and PG 1351+640, aimed at getting insights into the physics of quasar outflows. We find strong X-ray spectral variability on timescales of years. These variations can be well reproduced by variations of physical properties as the covering factor and column density of ionized gas along the ...

We study the X-ray and optical properties of 16 broad absorption line (BAL) quasars detected in a ?3 deg2 region common to the wide synoptic (W-1) component of the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) and the XMM Large Scale Structure Survey (XMM-LSS). The BAL fraction is found to be 10 per cent in the full sample, 7 per cent for the ...

The discovery and preliminary spectroscopy of the broad absorption line (BAL) QSO 0059-2735 (z/em/ = 1.595), which shows features never seen before in QSO spectra, are described. In addition to very broad high-ionization troughs of C IV and Si IV, it exhibits an extensive system of low ionization absorptions which include saturated ...

There exists a population of broad-line z~2 QSOs which have heavily absorbed X-ray spectra. These objects constitute ~10% of the population at luminosities and redshifts characteristic of the main producers of QSO luminosity in the Universe. Our follow up observations in the submm show that these QSOs are often embedded in ...

The transverse proximity effect is the expected decrease in the strength of the Ly? forest absorption in a QSO spectrum when another QSO lying close to the line of sight enhances the photoionization rate above that due to the average cosmic ionizing background. We select three QSOs from the Early Data Release of the Sloan Digital Sky ...

Recent detailed studies of narrow absorption line (NAL) systems in QSO spectra have revealed that at least 50% of QSOs have NALs associated with the central engine, and in most cases they are found to be outflowing. Will studies of NALs provide the much sought-after evidence for ubiquitous QSO feedback that can halt the formation of ...

There exists a significant population of broad line, z� 2 quasi-stellar objects (QSOs) which have heavily absorbed X-ray spectra. Follow-up observations in the submillimetre show that these QSOs are embedded in ultraluminous starburst galaxies, unlike most unabsorbed QSOs at the same redshifts and luminosities. ...

There exists a significant population of broad line, z� 2 quasi-stellar objects (QSOs) which have heavily absorbed X-ray spectra. Follow-up observations in the submillimetre show that these QSOs are embedded in ultraluminous starburst galaxies, unlike most unabsorbed QSOs at the same redshifts and luminosities. ...

The permitted emission-line profiles of Seyfert galaxies and QSOs often contain more light in the red wing than in the violet wing. Such an asymmetry can arise as a consequence of self-absorption of the line radiation in an expanding system of optically thick clouds. Calculations are presented of the anisotropy of ...

Approximately 10% of all optically selected radio quiet quasi-stellar objects (QSOs) exhibit broad absorption lines (BALs) in their spectra. The BALs are due to highly ionized gas containing ions such as N+4 and C+3, with outflow velocities typically in the range 10,000-30,000 km s-1. Approximately 5-15% of this class of QSO also ...

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 (~1023.5 cm-2) was obtained for PG 1411+442, even though it is one of the few BAL QSOs strongly ...

We present multifrequency observations of a sample of 15 radio-emitting broad absorption-line quasars (BAL QSOs), covering a spectral range between 74 MHz and 43 GHz. They mostly display convex radio spectra which typically peak at about 1-5 GHz (in the observer's rest frame), flatten at MHz frequencies, probably due to synchrotron ...

This proposal is part of our larger project to construct an ultraviolet spectral Atlas of low redshift QSOs, using low resolution spectra in the IUE Archive. Our intent is to produce a high quality compilation, with spectra having the best attainable signal-to-noise ratios, that can be used for detailed photometric and spectral line analyses. The purpose ...

The basic properties of broad emission-line profiles from quasars and Seyfert galaxies are suggested

The optical spectroscopy of the three quasars Q0118-031 A,B,C is presented. Low dispersion spectra showing the emission lines were obtained for all three objects, and intermediate dispersion spectra were obtained for objects B and C, to search for absorpt...

We analyze archived Chandra and XMM-Newton X-ray observations of 536 Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) quasars (QSOs) at 1.7<=z<=2.7 in order to characterize the relative UV and X-ray spectral properties of QSOs that do not have broad UV absorption lines (BALs). We constrain the fraction of ...

Recently, convincing evidence was found for extremely large X-ray absorption by column densities greater than 10^23 cm^-2 in broad absorption line quasars. One consequence of this is that any soft X-ray emission from these QSOs would be the scattered light or leaked light from partially covering absorbing material. ...

Results are presented for a spectroscopic survey of an intermediate (1.20z/sub em/ have velocity dispersion very similar to that expected if the absorbing material and the QSO are members of clusters of galaxies, and we interpret systems with vertical-bar z/sub em/-z/sub abs/ vertical-bar< or approx. =3000 km s/sup -1/ as predominantly associated with galaxy clusters. The remaining ...

COS G130M and G160M 20,000 resolution observations will be obtained for 17 QSOs to study cool, warm and hot gas in the cosmic web and in galaxy halos. 5 QSOs with z from 0.177 to 0.574 and sum z = 1.68 will be observed with S/N = 40-50 per resolution element. 12 QSOs with z = 0.286 to 0.669 and sum z = 5.57 will be observed with S/N = ...

We have imaged a 45' x 45' area centered on the Hubble Deep Field (HDF) in UBVRI passbands, down to the limiting magnitudes of approximately 21.5, 22.5, 22.2, 22.2, and 21.2, respectively. The principal goals of the survey are to identify quasi-stellar objects (QSOs) and to map structure traced by luminous galaxies and QSO absorption ...

We present moderate-resolution Cosmic Origins Spectrograph (COS) far-UV spectra of three QSOs that probe the extended gaseous halo of the nearby spiral galaxy ESO 157-G049 (cz = 1673 km/s; L = 0.1 L*) at impact parameters of 53, 66, and 124 kpc. H I Lyman-alpha absorption is detected at the galaxy redshift in the spectra of all three ...

The presence of dust in quasar absorbers, such as damped Ly? (DLA) systems, may cause the background QSO to appear reddened. We investigate the extent of this potential reddening by comparing the optical-to-infrared colors of QSOs with and without intervening absorbers. Our QSO sample is based on the Complete Optical and Radio Absorption ...

We report the discovery of the faint (V? 21.7) quasar QSO 03027-0010 at z=2.808 in the vicinity of Q 0302-003, one of the few quasars observed with STIS to study intergalactic He II absorption. Together with another newly discovered QSO at z=2.29, there are now 6 QSOs known near the line of sight towards Q 0302-003, of which 4 are ...

(1977), the authors reexamine the possibility multiple absorption spectra of QSOs are due to gas in the disks, coronae, or halos of intervening galaxies. ...

We present a brief overview of the ongoing Complete Optical and Radio Absorption Line System (CORALS) survey. We review the results of our survey for z>2.2 damped Lyman alpha systems (DLAs) and present the preliminary results of an extended survey to lower redshifts (0.7

The probability of Faraday rotation in various types of metal-line absorbers is computed by combining the incidence of Faraday rotation in a sample of radio-selected QSOs with the incidence of foreground metal-line absorption. The sample is divided into subsets with and without damped Ly-alpha ...

Photometric data for nearly 250 quasars, BL Lacertids, and active galaxies have been obtained at the Rosemary Hill Observatory during a continuous 13-year monitoring program. Long-term optical records for 130 of these sources are employed in an effort to assess the physical and cosmological properties of quasi-stellar objects. Photographic P and B magnitudes were obtained with the 76- and 46-cm ...

High-redshift QSOs often have rich absorption spectra, which may be formed in clouds or filaments either associated with the QSO or at cosmological distances from the continuum source. The strongest lines in these spectra often are split into two or more components separated by about one line width. It has usually ...

From a sensitive survey of associated narrow absorption lines (NALs) in the low-redshift HST Quasar Absorption Line Key Project sample of QSOs, we attempt to uncover the underlying cause of intrinsic NALs and gain insight into the physical mechanism behind the production of NAL gas. From other ...

We present the results of further low-dispersion spectroscopic observations using the Anglo-Australian 4 m telescope for 32 objects identified with Parkes radio sources. Included are redshifts for 26 QSOs and one radio galaxy. Three of the QSOs have redshifts in excess of 2.5 and one of these has a redshift of 3.1. Two other QSOs ...

FROM PROGRAM 5455: About 10% of all radio quiet QSOs exhibit broad absorption lines (BALs) in their spectra. The BALs come from a mostly highly ionized region outflowing from the central source at speeds up to many tens of thousands of km/s. Observational constraints on models require that the covering factor of the BAL region be small ...

The chemical evolution of the high redshift intergalactic and interstellar media of galaxies is studied using QSO absorption lines. The redshift evolution of damped Lyman alpha (DLA) system metallicity is studied down to z=0.5, and no significant increase in metals is found. The CIV/HI ratio in the Lyman alpha forest is investigated at z approximately 3 ...

The presence of dust in quasar absorbers, such as damped Lyman alpha (DLA) systems, may cause the background QSO to appear reddened. We investigate the extent of this potential reddening by comparing the optical-to-infrared (IR) colors of QSOs with and without intervening absorbers. Our QSO sample is based on the Complete Optical and Radio Absorption ...

The gas producing the broad absorption lines (BALs) of QSOs appears to have heavy element abundances one to two orders-of-magnitude great than solar (Turnshek 1995, ESO Workshop on QSO Absorption Lines; Korista et al. 1995, Ap. J., in press). Junkarrinen et al. (1995, B.A.A.S., 27, 872; also ...

Spectrophotometric observations of Mg II lambda2798 and H..beta.. emission in 14 QSOs, four Seyfert 1 galaxies, and two broad-line radio galaxies are presented. Both broad and narrow components of Mg II lambda2798 are found to occur. In most cases the profiles of the broad components of Mg II and H..beta.. are observed to be virtually identical, suggesting ...

Context: There is growing evidence for the presence of blueshifted Fe K absorption lines in a number of radio-quiet AGNs and QSOs. These may be fundamental to probe flow dynamics near supermassive black holes. Aims: Here we aim to verify and better characterise the existence of such Fe K absorption at ~8-10 keV in ...

For our CaII survey we made use of the ESO data archive and retrieved all publically available (as of Sep. 2008) absorption-line data for low- and high-redshift QSOs observed with the Ultraviolet and Visual Echelle Spectrograph (UVES) on the VLT. This enormous data archive (Spectral Quasar Absorption Database, SQUAD; PI: M.T. Murphy) ...

A CCD spectroscopic survey of Mg II and Mg I absorption lines in a C IV selected sample of 35 metal systems, observed toward 12 QSOs between z = 1.1 and z = 2.1, is reported. Six Mg I and 10 Mg II absorption lines are detected in 33 C IV clouds, and some peculiarities are noted. The complex or ...

We have studied a sample of 809 MgII absorption systems with 1.0 <=zabs<= 1.86 in the spectra of Sloan Digital Sky Survey quasi-stellar objects (QSOs), with the aim of understanding the nature and abundance of the dust and the chemical abundances in the intervening absorbers. Normalized, composite spectra were derived, for abundance measurements, for ...

We searched for evidence of soft X-ray absorption by hot gas in the vicinity of the Galaxy in a small sample of 15 type I active galactic nuclei (AGNs) observed with the high resolution X-ray gratings on board Chandra. We find that around half of the sight lines in our sample exhibit absorption due to local H- or He-like oxygen (or ...

Using the Keck 10 m telescope data with the HIRES spectrograph, we analyzed the evolution of Lymanff forest clouds at z ? 2 down to the HI column density 10 12:8 cm \\Gamma2 . The number density per unit column density does not change with redshifts at lower HI cloumn density (N HI ! 10 14 cm \\Gamma2 ), while the forest clouds at higher column density disappear rapidly. The cutoff b ...

It has 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 found ``soft X-ray-loud'' BALQSOs that, by definition, have soft X-ray (0.3 keV) to UV (3000 �) flux density ratios ...

We present far-UV spectra obtained with the Cosmic Origins Spectrograph (COS) of the QSOs VII Zw 244 and SBS 1122+594, which both have foreground galaxies within a projected distance of 35 kpc. The COS spectrum of VII Zw 244 (z = 0.131) shows strong (but not damped) Lyman alpha absorption as well as absorption from C II, C IV, Si III, ...

The epoch of reionization (EoR) corresponds to a 'cosmic phase transition', when the neutral intergalactic medium (IGM) becomes ionized by the first stars and/or AGN. While the discoveries of Gunn-Peterson (GP) absorption troughs in the spectra of the highest redshift QSOs, and large scale polarization of the CMB, have set the first hard constraints on the ...

The epoch of reionization (EoR) corresponds to a 'cosmic phase transition', when the neutral intergalactic medium (IGM) becomes ionized by the first stars and/or AGN. While the discoveries of Gunn-Peterson (GP) absorption troughs in the spectra of the highest redshift QSOs and large scale polarization of the CMB have set the first hard constraints on the ...

High-resolution (0.8 A FWHM) spectroscopic observations over the wavelength range 3800 A--5400 A are presented for the two bright southern QSOs, Q0002--422 (z/sub em/=2.763) and Q0453--423 (z/sub em/=2.656). For these two objects we list 80 and 77 absorption lines, respectively, and identify five absorption-line ...

The redshifted 21-cm and Mg II absorption lines observed in the QSO 3C 286 and the BL Lacertae object 0735+178, respectively, are analyzed to determine the location of the absorbing gas. We first describe evidence which supports the presence of neutral hydrogen intrinsic to QSOs, and then examine excitation conditions ...

Observations of the QSO PKS 2126--158 (Z/sub em/=3.280) at 0.8 A resolution from 4l53 A to 6807 A reveal 113 absorption lines. There are two certain absorption-line systems at z/sub abs/=2.6381 and 2.7685, and a possible third system at z/sub abs/=2.3938. The ions H I, C II, C IV, O I, Al II, Si II, Si III, Si IV, and Fe II are ...

Recent progress made in the instrumentation, observational techniques and data analysis tools for studying various astrophysical and astronomical phenomena is explored. Features of the quiet solar transition region, the evolution of H II regions, and stellar molecules are discussed. Maximum entropy image restoration techniques are described, as are emission-line regions of ...

We present optical light curves of 19 radio-quiet (RQ) broad absorption line (BAL) quasi-stellar objects (QSOs) and study their rapid variability characteristics. Systematic CCD observations, aided by a careful data analysis procedure, have allowed us to clearly detect any such microvariability exceeding 0.01-0.02 mag. Our observations ...

THIS IS PART Three OF PROPOSAL 3801. IT CONTAINS 40 TARGETS OF HIGH PRIORITY. EXCEPT FOR TARGETS, THIS PROPOSAL IS IDENTICAL TO 3801. Targets are in order of decreasing priority. Priority matters a lot. Best targets are listed first. Ultraviolet images will be obtained in snapshot mode of the 500 known high-redshift (z > 2.8) QSOs in order to identify the few (about 20) ...

THIS IS PART TWO OF PROPOSAL 3801, CONTAINING 55 TARGETS OF PRIORITY 7,8 AND 9. EXCEPT FOR TARGETS, THIS PROPOSAL IS IDENTICAL TO 3801, WHICH HAS 87 TARGETS OF PRIORITY 3,4,5 AND 6. Ultraviolet images will be obtained in snapshot mode of the 500 known high-redshift (z > 2.8) QSOs in order to identify the few (about 20) targets which have sufficient ultraviolet flux for ...

MgII QSO absorption lines detected in the spectra of background QSOs were used over a decade ago to infer that all redshift z > 0.2 galaxies have gaseous halos of radius ~ 60 kpc. The actual size of the halo was believed to be proportional to the luminosity of the galaxy. However, these conclusions are now much harder to understand ...

(Abridged) We present the first results from the Complete Optical and Radio Absorption Line System (CORALS) survey. We have compiled a homogeneous sample of radio-selected QSOs from the Parkes Catalogue and searched for damped Lyman alpha systems (DLAs) towards every target, irrespective of its optical magnitude. This approach ...

Two high redshift (z = 3.18 & z = 3.23) QSOs, separated by only eight arcminutes, were discovered as part of the Large Bright QSO Survey (LBQS). Two strong absorption systems (observed-frame equivalent widths > 20 Angstroms) are seen on each line of sight, and the absorption systems are at the same redshifts ...

The large number of apparently correlated C IV absorption systems observed in the lines of sight to the wide QSO pair Tol 1037-2704 (zem = 2.193) and Tol 1038-2712 (zem = 2.331) between the redshifts 1.88 ? z ? 2.15 is thought to be produced by an intervening supercluster. We present high-resolution echelle spectra of Tol 1037-2704 and Tol 1038-2712, as ...

The APM multicolor survey for bright z > 4 objects, covering 2500 deg^2^ of sky to m_r_ ~ 19, resulted in the discovery of 31 quasars with z ~> 4. High signal-to-noise optical spectrophotometry at 5 A resolution has been obtained for the 28 quasars easily accessible from the northern hemisphere. These spectra have been surveyed to create new samples of high-redshift Lyman-limit systems, ...

This thesis examines the dynamical role of radiation in two astrophysical environments: (a) shear layers between astrophysical jets and their surrounding medium and (b) broad absorption line (BAL) regions of QSOs. At the interface between a jet and its ambient medium, a shear flow forms. In many astrophysical situations it can be shown ...

We describe the application of non-negative matrix factorization to generate compact reconstructions of quasar spectra from the Sloan Digital Sky Survey (SDSS), with particular reference to broad absorption line quasars (BALQSOs). BAL properties are measured for SiIV?1400, CIV?1550, AlIII?1860 and MgII?2800, resulting in a catalogue of 3547 BALQSOs. Two ...

From a study of broad absorption line (BAL) + infrared (IR) + FeII quasi-stellar objects (QSOs) [using deep Gemini Multi-Object Spectrograph Integral Field Unit (GMOS-IFU) spectroscopy], new results are presented for IRAS 04505-2958. Specifically, we have studied in detail the outflow (OF) process at two large galactic scales: (i) two ...

Published data on the average metallicities and abundance ratios for absorption-line systems in high-redshift quasars suggest that a dichotomy may exist between the chemical composition of damped Lyman alpha (Lyalpha) systems (interpreted as intervening galaxies in the QSO line of sight) and the z_abs~=z_em absorption- ...

We present results from the X-ray portion of a multi-wavelength study of local ULIRGs and QSOs called QUEST (Quasar-ULIRG Evolution STudy). The data consist of new and archival X-ray data on 40 ULIRGs and 26 Palomar Green (PG) QSOs taken with Chandra and XMM-Newton. A combination of traditional and hardness ratio spectral fitting methods is used to ...

We present results from the X-ray portion of a multi-wavelength study of local ULIRGs and QSOs called QUEST (Quasar-ULIRG Evolution STudy). The data consist of new and archival X-ray data on 40 ULIRGs and 26 Palomar Green (PG) QSOs taken with Chandra and XMM-Newton. A combination of traditional and hardness ratio spectral fitting methods is used to ...

Emission line strengths, low-resolution line profiles, and continuum energy distributions were measured for 14 low-redshifts QSOs. The profiles of many of the broad emission lines are quite symmetrical and are in excellent agreement either with electron-scattering profiles, or, as has been shown by ...

We analyse the properties of Mg II absorption systems detected along the sightlines toward GRBs using VLT-UVES GRB afterglow spectra. We extend previous studies to smaller equivalent widths (typically Wr>0.3 �). We increase the absorption length for strong systems to ?z = 31.5 using intermediate resolution observations reported in the literature. We ...

Context. Q 0151+048 is a physical quasar (QSO) pair at z ~ 1.929 with a separation of 3.3 arcsec on the sky. In the spectrum of the brighter member of this pair, Q 0151+048A, a damped Ly? absorber (DLA) is observed at a higher redshift. We have previously detected the host galaxies of both QSOs, as well as a Ly? blob whose emission surrounding Q 0151+048A extends over 5 � ...

We present results from a BeppoSAX observation of the broad absorption line (BAL) QSO CSO 755, which was observed as part of our program to investigate the X-ray properties of highly polarized BAL QSOs. CSO 755 is clearly detected by the BeppoSAX Medium-Energy Concentrator Spectrometers, making it the highest redshift (z=2.88) and most ...

Hubble Space Telescope Faint Object Spectrograph G270H spectra of four moderate-to high-redshift broad absorption line (BAL) QSOs are presented. In addition, evidence is discussed that indicates that the gas that gives rise to the BALs has nonuniform ionization and enhanced abundances. In the context of a photoionization model, ...

We study the degree of chemical enrichment in the broad emission line regions (BELRs) of two QSOs with unusually strong nitrogen emission lines. The N V ?1240/C IV ?1549 intensity ratio is often used as a metallicity indicator for QSOs. The validity of this approach can be tested by studying objects in which the N ...

Rest-frame UV spectral lines of star-forming galaxies are systematically offset from the galaxies' systemic redshifts, probably because of large-scale outflows. We calibrate galaxy redshifts measured from rest-frame UV lines by utilizing the fact that the mean H I Ly? absorption profiles around the galaxies, as seen in spectra of ...

Photoionization models dictate that many prominent quasar emission lines are sensitive to both the luminosity and shape of the quasars high- energy continuum-primarily the extreme ultraviolet (EUV) and soft X-ray continuum. Unfortunately, the EUV band is severely obscured by Galactic absorption. Using data from the adjacent UV and soft X-ray bandpasses, we ...

We use the Sloan Digital Sky Survey, along with the NRAO VLA Sky Survey and the Westerbork Northern Sky Survey to define a sample of 746 radio-loud quasars and measure their 330 MHz-1.4 GHz spectral indexes. Following previous authors we take the radio spectral index as an indicator of the orientation towards the quasars such that more pole-on sources tend to have flatter spectral indexes. We use ...

Many AGN are highly variable sources. Some of these show a pronounced time delay between variations seen in their optical continuum and in their emission lines. ``Echo mapping'' is a technique that uses these time delays to measure the geometry and kinematics of the gas inside the AGN, near the supermassive black hole. The technique is immensely powerful, but the results so ...

We will exploit the large field of view of the MOSAIC camera on the KPNO 4-m telescope to conduct a census of foreground QSOs in the fields of six rare far UV transmitting QSO sightlines useful for studying He II reionization. Deep multicolor imaging will allow us to photometrically select the faint foreground QSOs responsible for doubly ionizing helium at ...

Spectroscopic data for five low-redshift QSOs taken over several years are presented as evidence for

The broad line profiles of active galaxies are consistent with emission from the surface of an accretion disk ionized by an ultraviolet continuum emitted from a linear or point source of continuum above the disk. If the point source is offset from the axi...

We study broad absorption line quasars (BALQSOs) because these objects, in particular, probe the high velocity gas ejected by luminous accreting black holes. The variability timescales of BALs can help constrain the size, location, and dynamics of the emitting and absorbing gas near the supermassive black hole. We have obtained multi-epoch spectroscopy of ...

The relation that objects with flat soft X-ray spectra have weak optical Fe II emission is not confirmed for a sample of 34 Quasi Stellar Objects (QSOs). Objects with strong optical Fe II emission have narrow H beta lines. This trend is much weaker with L...

We report results from a survey of Mg II absorbers in the spectra of background quasi-stellar objects (QSOs) that are within close angular distances to a foreground galaxy at z < 0.5, using the Magellan Echellette Spectrograph. We have established a spectroscopic sample of 94 galaxies at a median redshift of langzrang = 0.24 in fields around 70 distant background ...

Currently we can only account for half of the baryons {or less} expected to be found in the nearby universe based on D/H and CMB observations. This "missing baryons problem" is one of the highest-priority challenges in observational extragalatic astronomy. Cosmological simulations suggest that the baryons are hidden in low-density, shock-heated intergalactic gas in the log T = 5 - 7 range, but ...

The proximity effect (PE) of QSOs is believed to be useful in constraining the QSO lifetime. Observations of the PE so far, however, give apparently contradictory results�some are consistent with a long QSO lifetime (gsim a few 107 yr), but others appear to be only consistent with a short QSO lifetime (lsim 106 yr). In this paper, we show that this apparent contradiction may ...

A recent FUSE snapshot observation reveals that HE,0153--4520 z_ QSO 0.451) is the third brightest moderate redshift (z > 0.4) QSO at FUV wavelengths. The line of sight to HE,0153--4520 provides an outstanding opportunity to obtain information on EUV absorption lines formed in the highly ionized IGM. Our proposed 250 ksec ...

We propose XMM EPIC spectroscopy of the five most X-ray luminous radio-quiet QSOs found in the ROSAT Bright Survey (RBS). The RBS contains the brightest X-ray sources in the sky. Hence, the sample marks the high end of the local (z< 0.5) QSO luminosity function. Self-consistent disk reflection models predict strong, neutral Fe lines emission in low ...

We will observe and analyze a sample of four QSOs to verify tentative detections of the very high ionization broad emission line, Ne VIII 774. This line has not been securely identified in any QSO, but our analysis of one probable detection shows that it would require a new understanding of QSO environments. In particular, (1) Ne VIII ...

UV spectra of the nucleus of the elliptical galaxy Arp 102B were obtained with the {ital HST}`s Faint Object Spectrograph in order to investigate the UV emission-line counterparts of its unusual double-peaked Balmer lines. Broad MgII {lambda}2798 is present with nearly the same profile as the Balmer lines (peaks separated by ...

An analysis is given of high resolution observations of metal-absorption line systems in the spectra of 4 QSOs made with the echelle spectrograph on the Mayall 4-meter telescope at Kitt Peak National Observatory. High spectral -resolution (9 to 18 km cdot s^{ -1}) observations were obtained for the QSOs S5 0014 + ...

We report the detection of deuterium absorption at redshift 2.525659 toward Q1243+3047. We describe improved methods to estimate the deuterium to hydrogen abundance ratio (D/H) in absorption systems, including improved modeling of the continuum level, the Ly? forest, and the velocity structure of the absorption. Together with improved ...

We propose spectroscopic observations with COS of eight z~3 QSOs that we found to be bright in the far ultraviolet. Our aim is to study intergalactic absorption caused by the onset of the He II Lyman forest. Several lines of evidence suggest that helium reionization occurred at z~3. Understanding this process is critical for a complete ...

In this paper we present the first results of a study of BAL QSOs (at low and high redshift), based on very deep Gemini GMOS integral field spectroscopy. In particular, the results obtained for the nearest BAL IR-QSO Mrk 231 are presented. For the nuclear region of Mrk 231, the QSO and host galaxy components were modelled, using a new technique of decoupling 3D spectra. From ...

Following the suggestion by Walsh, Carswell, and Weymann that the ratio of the observed wavelengths of the C IV and C III) (lambdalambda 1549, 1909) emission lines in the double QSO 0957+561 differs significantly from the expected value, the distribution of this ratio in a sample of 189 other QSOs is examined. The mean value of the ratio is consistent with ...

UV/optical emission lines offer some of the most detailed information obtainable about the intrinsic properties of quasars. Studies of the density, ionization and metal abundance of gas near the accreting black hole are probed through an intriguing but po...

A photograph filtering technique has been developed to search for QSOs with objective prism plates. After off-focus reproduction, the SNR increases and some spectral lines in the prism spectra may be recongized by eye agianst the noise. The principle of this technique is discussed.

The emission line and continuum characteristics of a sample of 18 low redshift QSOs from the IUE Archives are presented. The spectral index is found to have a mean value of 1.22, which is considerably steeper than the index of the same spectral region for...

We present high resolution ( ~ 0.15 Angstroms) echelle spectra of the wide QSO pair Tol 1037-2704 (z_em=2.193) and Tol 1038-2712 (z_em=2.331) as well as two neighbouring quasars from the Bohuski and Weedman survey. The components of the Tololo pair are separated by 17.9(') or ~ 4.3 h(-1}_{100) Mpc for q_0 = 0.5, and exhibit a large number of apparently correlated C iv ...

We present a preliminary analysis of a large spectroscopic survey of z � 2-3 star-forming galaxies conducted in fields of very bright background QSOs whose lines of sight pass through the survey volume. By analyzing the high resolution, high S/N QSO spectra near the redshifts of the foreground galaxies, we measure the impact of star-forming galaxies on ...

Quasar absorption lines in flat universes with nonzero cosmological constant Lambda are examined and

... Accession Number : AD0619963. Title : INVESTIGATION OF NARROW LINE ABSORPTIONS IN SINGLE CRYSTAL CALCITE. ...

... Title : ABSORPTION LINE SERIES AND AUTOIONIZATION RESONANCE STRUCTURE ANALYSIS IN THE ULTRAVIOLET SPECTRUM OF SR I,. ...

We examine the relationship between galaxies and the intergalactic medium at z < 1 using a group of three closely spaced background quasi-stellar objects (QSOs) with zem ~ 1 observed with the Hubble Space Telescope. Using a new grouping algorithm, we identify groups of galaxies and absorbers across the three QSO sightlines that may be physically linked. There is an excess ...

Nov 1, 1977 ... This atlas of infrared absorption line contains absorption line parameters (line strength vs.

Centrifugally driven winds from the surfaces of magnetized accretion disks have been recognized as an attractive mechanism of removing the angular momentum of the accreted matter and of producing the bipolar outflows and jets that are often associated with compact astronomical objects. As previously suggested in the context of young stellar objects, such winds have unique observational ...

While the relationships between observed colors and redshifts for QSOs have been studied, apparently no such study has been conducted for active galaxies (AGs). The present investigation is concerned with the redshift-color and color-color relationships of QSOs and AGs, individually and combined. The investigation has the objective to find out about the ...

I had the privilege, many years ago, to be supervised by Alfonso Cavaliere in my Master thesis work. I remember the great patience and enthusiasm with which, in a warm summer day, he presented to me a score of exciting astrophysical problems. We finally determined to study the relationship of QSOs and BL Lacs�then considered rather exotic object�with normal galaxies. In ...

The Magellanic Bridge {the MB} is a physical connection between the Large Magellanic Cloud {LMC} and the Small Magellanic Cloud {SMC}. The MB contains a young stellar population that was probably formed in local molecular clouds, while it is still not fully settled whether the larger Magellanic Stream, produced by the LMC/SMC unit sweeping through the Milky Way halo, contains only gas or has any ...

The optical absorption lines of quasars are examined, and implications of the lines for the physical

We present deep ground based imaging of the environments of five quasi-stellar objects (QSOs) that contain sub-damped Lyman ? (sub-DLA) systems at z < 1 with the Southern Observatories Astrophysics Research (SOAR) telescope and SOAR Optical Imager (SOI) camera. We detect a clear surplus of galaxies in these small fields, supporting the assumption that we are detecting the ...

We propose to obtain ultraviolet spectroscopy of the halo of M31, to probe for a hot corona on scales of 30-40 pc from the galaxy. We seek to obtain absorption line spectra of O I, Mg II, Si II, C IV, and Si IV toward bright QSOs located behind the galaxy. One of the sightlines falls on the projection of Ibata's giant stream. All ...

A major goal in the study of AGN outflows is the determination of the ionization equilibrium and abundances {IEA} in broad absorption line {BAL} QSOs. In the last few years it has become clear that partial coverage of the continuum source and saturation are common in BALs, and these frustrate attempts to determine the IEA from ...

This dissertation describes my analysis of XMM-Newton observations of six Active Galactic Nuclei (AGN), concentrating on the high resolution spectroscopy of soft X-ray absorption features, and discusses the results in the context of the origins and astrophysical implications of ionised outflows in AGN. I studied two Seyfert galaxies (NGC 3783 and NGC 7469) and four BL Lac ...

The absorption features seen in the spectra of quasi-stellar objects (QSOs) provide a unique opportunity to probe the galactic and intergalactic regions which intersect the lines of sight (LOS). Understanding the environment of these absorbers allows us to make a connection with physical structures and study the properties and ...

We discuss new Hubble Space Telescope spectroscopy of the radio-loud quasar 3C 288.1. The data cover ~590 to ~1610 � in the quasar rest frame. They reveal a wealth of associated absorption lines (AALs) with no accompanying Lyman-limit absorption. The metallic AALs range in ionization from C III and N III to Ne VIII and Mg X. We use ...

The clustering properties of a three-dimensional sample of low-redshift absorption line systems concentrated towards the North and South Galactic Poles, and obtained with the Faint Object Spectrograph of the Hubble Space Telescope, are examined. There are 588 total absorption lines detected in the complete sample ...

We describe medium-resolution spectroscopic observations taken with the ESO Multi-Mode Instrument (emmi) in the Ca ii K line (?_air=3933.661 �) towards 7 QSOs located in the line-of-sight to the Magellanic Bridge. At a spectral resolution R = ?/?? = 6000, five of the sightlines have a signal-to-noise (S/N) ratio of 20 or higher. ...

This dissertation details a search for star-forming galaxies at z/ [~> 1, using narrow-band near-infrared filters to detect redshifted H?+ NII emission from objects in fields containing QSOs or absorption-line systems. The observations were obtained at Lick observatory with the UCLA Two-Channel Near-Infrared Camera on the Shane 3 m telescope and at Keck ...

The thesis consists primarily of 4 parts, which are separate but related insofar as each makes use of spectra of high redshift QSOs in order to investigate the properties of intervening gaseous material: (1) Wideslit spectrophotometry of a sample of very high redshift QSOs is used in combination with high resolution observations of QSO Lyman a forests to ...

Spectra with a resolution of about 2 A have been obtained of the QSO pair Tol 1037 - 2704 and Tol 1038 - 2712. The new observations and the reductions of the raw data are described, and analyses of the spectra, including a critical discussion of the absorption and emission redshifts, is given. The possible coincidences in absorption redshift and their ...

We report results from a survey of Mg II absorbers in the spectra of background quasi-stellar objects (QSOs) that are within close angular distances to a foreground galaxy at z < 0.5, using the Magellan Echellette Spectrograph. We have established a spectroscopic sample of 94 galaxies at a median redshift of (z) = 0.24 in fields around 70 distant background ...

QSO Lyman-alpha forest absorption systems have traditionally been considered intergalactic primordial gas clouds, but new data suggest that many of them at high redshift contain metals with abundances of C/H eq -3, which means 10^-3 solar. We propose to search for metals in HST spectra of LyAlpha forest systems at low redshift. The search has two parts: first we look for 2 ...

The broad line profiles of active galaxies are consistent with emission from the surface of an accretion disk ionized by an ultraviolet continuum emitted from a linear or point source of continuum above the disk. If the point source is offset from the axis of the disk, then the line peak is shifted from zero velocity in a way that resembles observed cases. ...

Context. The variation of the dimensionless fundamental physical constant ? = mp/me can be checked through observation of Lyman and Werner lines of molecular hydrogen in the spectra of distant QSOs. Only few, at present four, systems have been used for the purpose providing different results between the different authors. Aims: Our intention is to asses ...

The mass of the central black holes in Seyfert galaxies and QSOs can be determined from the broad emission lines and the reverberation method. Using the measured black hole mass and the bolometric or ionizing luminosity, the accretion rate can be estimated. Compiling a sample of Seyfert 1 galaxies and QSOs with reliable central masses, ...

Composite spectra of 85 proximate absorbers [log N(H I) ? 20 cm-2 and velocity difference between the absorption and emission redshifts, ?V < 10 000 km s-1] in the Sloan Digital Sky Survey are used to investigate the trends of metal-line strengths with velocity separation from the quasi-stellar object (QSO). We construct composites in three velocity ...

We present optical and X-ray data for a sample of serendipitous XMM-Newton sources that are selected to have 0.5-2 versus 2-4.5 keV X-ray hardness ratios which are harder than the X-ray background. The sources have 2-4.5 keV X-ray flux >=10-14 erg cm-2 s-1, and in this paper we examine a subsample of 42 optically bright (r < 21) sources; this subsample is 100 per cent spectroscopically ...

We examine whether the spectral energy distribution of UV continuum emission of active galactic nuclei changes during flux variation. We used multi-epoch photometric data of QSOs in Stripe 82 observed by the Sloan Digital Sky Survey (SDSS) Legacy Survey and selected 10 bright QSOs observed with high photometric accuracies, in the redshift range of z = ...

A model has been constructed for the selection and evolutionary effects present in a population of QSO metal-line absorption redshift systems taken from a large catalog of data collected under various conditions. For all but a small subset of the systems, the model is shown to be successful in describing these effects. The model is then used in ...

Context. We present near-IR spectroscopy of a sample of luminous (MB - 27.5; Lbol > 1014 L?), sub-millimeter-detected, dusty (Md ~ 109 M?), radio-quiet quasi-stellar objects (QSOs) at z ~ 2. Aims: A primary aim is to provide a more accurate QSO redshift determination in order to trace kinematics and inflows/outflows in these sub-mm bright QSOs. ...

The Sloan Digital Sky Survey (SDSS) quasar J092712.65+294344.0 has been proposed as a candidate for a supermassive black hole ({approx}10{sup 8.8} M {sub sun}) ejected at high speed from the host galactic nucleus by gravitational radiation recoil, or alternatively for a supermassive black hole binary. This is based on a blueshift of 2650 km s{sup -1} of the broad emission ...

We searched for evidence of the reddening of background quasi-stellar object (QSO) spectra from the Sloan Digital Sky Survey (SDSS) due to dust in intervening damped Lyman ? systems (DLAs). We utilize the two Data Releases DR5 and DR7 to arrive at sample sizes of 475 (DR5) and 676 (DR7) absorbers, based on two different published lists of SDSS DLAs. Both samples span roughly the redshift range of ...

We present HST STIS observations of four quasar pairs with redshifts 0.84absorption lines detected in the spectra of adjacent ...