This is the second of two papers reporting observations and analysis of the unusually bright (m_b=14.4), luminous (M_B=-25.5), nearby (z=0.192) narrow-line quasar PHL 1811. The first paper reported that PHL 1811 is intrinsically X-ray weak, and presented a spectral energy distribution (SED). Here we present HST STIS optical and UV spectra, and ground-based optical spectra. The optical and UV line emission is very unusual. There is no evidence for forbidden or semiforbidden lines. The near-UV spectrum is dominated by very strong FeII and FeIII, and unusual low-ionization lines such as NaID and CaII H&K are observed. High-ionization lines are very weak; CIV has an equivalent width of 6.6A, a factor of ~5 smaller than measured from quasar composite spectra. An unusual feature near 1200A can be deblended in terms of Lyα, NV, SiII, and CIII* using the blueshifted CIV profile as a template. Photoionization modeling shows that the unusual line emission can be explained qualitatively by the unusually soft SED. Principally, a low gas temperature results in inefficient emission of collisionally excited lines, including the semiforbidden lines generally used as density diagnostics. The emission resembles that of high-density gas; in both cases this is a consequence of inefficient cooling. PHL 1811 is very unusual, but we note that quasar surveys are generally biased against finding similar objects.
Abridged) In the SDSS, several unusual QSOs have been discovered that have very blue rest-frame UV spectra but no discernible emission lines. Their UV spectra strongly resemble that of the newly discovered quasar PHL 1811 ($z=0.192$; $\rm M_{V}=-25.9$). With magnitudes of $B = 14.4$ and $R = 14.1$, PHL 1811 is the second brightest quasar known with $z>0.1$ after 3C 273. Optically it is classified as a Narrow-line Seyfert 1 galaxy (NLS1). Objects of this class are generally strong soft X-ray emitters, but a BeppoSAX observation of PHL 1811 showed that it is anomalously X-ray weak. The inferred …
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 of sight absorption is very strong with N_H=5 x 10^{23} cm^{-2}, (3) the absorber does not cover the source completely; the covering fraction is about 90%. This is consistent with the large optical polarization observed in this source, implying multiple lines of sight. The most surprising result of this observation is that (4) the spectrum of this BALQSO is n…
We report results from an 18-day ROSAT HRI monitoring campaign on the ultrasoft Narrow-Line Seyfert 1 (NLS1) class quasar PHL 1092. This luminous, radio-quiet quasar showed strong X-ray variability in a short ROSAT PSPC observation, and ROSAT HRI monitoring of the similar object IRAS 13224-3809 revealed extreme variability on intermediate timescales. We wanted to determine whether remarkable X-ray variability persistently occurs in PHL 1092, and we also wanted to search for outstanding variability events that constrain emission processes. Given the large luminosity of PHL 1092 (about 5x10^{45}…
This is the first of two papers reporting observations and analysis of the unusually bright (m_b=14.4), luminous (M_B=-25.5), nearby (z=0.192) narrow-line quasar PHL 1811, focusing on the X-ray properties and the spectral energy distribution. Two Chandra observations reveal a weak X-ray source with a steep spectrum. Variability by a factor of 4 between the two observations separated by 12 days suggest that the X-rays are not scattered emission. The XMM-Newton spectra are modelled in the 0.3--5 keV band by a steep power law with Γ= 2.3\pm 0.1, and the upper limit on intrinsic absorption is 8.7 …
The extraordinarily bright quasar PHL 1811 at a redshift z = 0.192 provides an attractive opportunity to use ultraviolet absorption-line spectroscopy to study the properties of gas systems in the local universe. An R = 20,000 far-UV spectrum recorded by FUSE revealed 7 extragalactic absorption systems, one of which is a Lyman limit system at z = 0.08093 accompanied by three systems having redshifts which differ from it by less than 0.008. The abundance of O with respect to Fe in the Lyman limit system is not much different from the solar abundance ratio. Supplementary low resolution spectra re…
We report on the relative optical variability of the three brightest nearby quasars, 3C 273, PDS 456, and PHL 1811. All three have comparable absolute magnitudes, but PDS 456 and PHL 1811 are radio quiet. PDS 456 is a broad-line object, but PHL 1811 could be classified as a high-luminosity Narrow-Line Seyfert 1 (NLS1). Both of the radio-quiet quasars show significant variability on a timescale of a few days. The seasonal rms V-band variability amplitudes of 3C 273 and PDS 456 are indistinguishable, and the seasonal rms variability amplitude of PHL 1811 was only exceeded by 3C 273 once in 30 ye…
We report the discovery of a new bright quasar PHL 1811 as part of a followup program to identify bright quasars in the FIRST radio survey. With B=13.9, R=13.9, and z=0.192, this quasar is now the second brightest quasar (in apparent magnitude) known beyond z=0.1. Optically classified as a Narrow-line Seyfert 1 galaxy (NLS1), PHL 1811 is unusual for an object in this class in that it was not detected in X-rays in the ROSAT All Sky survey or in any previous X-ray survey. A follow-up BeppoSAX observation confirms that it is deficient in X-rays compared with other quasars, but poor signal to nois…
The narrow-line quasar PHL 1092 was observed by XMM-Newton at two epochs separated by nearly thirty months. Timing analyses confirm the extreme variability observed during previous X-ray missions. A measurement of the radiative efficiency is in excess of what is expected from a Schwarzschild black hole. In addition to the rapid X-ray variability, the short UV light curves (< 4 hours) obtained with the Optical Monitor may also show fluctuations, albeit at much lower amplitude than the X-rays. In general, the extreme variability is impressive considering that the broad-band (0.4-10 keV rest-fram…
The spectrum of the quasar PHL 1226 is known to have a strong Mg II and sub-damped Lyman-alpha (sub-DLA) absorption line system with N(HI)=(5+/-2)*10^19 cm^-2 at z=0.1602. Using integral field spectra from the Potsdam Multi Aperture Spectrophotometer (PMAS) we investigate a galaxy at an impact parameter of 6".4 which is most probably responsible for the absorption lines. A fainter galaxy at a similar redshift and a slightly larger distance from the QSO is known to exist, but we assume that the absorption is caused by the more nearby galaxy. From optical Balmer lines we estimate an intrinsic re…
We have cross-correlated the SDSS DR3 Schneider et al. (2005) quasar catalog with the XMM-Newton archive. Color and redshift selections (g - r > 0.5 and 0.9 z < 2.1) result in a sample of 17 red, moderate redshift quasars. The redshift selection minimizes possible contamination due to host galaxy emission and Lyalpha forest absorption. Both optical and X-ray information are required to distinguish between the two likely remaining causes of the red colors: 1) dust-reddening and 2) an intrinsically red continuum. We find that 7 of 17 quasars can be classified as probable `intrinsically red' obje…
Growing amount of observations indicate presence of intrinsically faint quasar subgroup (a few % of known quasars) with noncosmological quantized redshift. Here we find an analytical solution of Einstein equations describing bubbles made from axions with periodic interaction potential. Such particles are currently considered as one of the leading dark matter candidate. The bubble interior possesses equal gravitational redshift which can have any value between zero and infinity. Quantum pressure supports the bubble against collapse and yields states stable on the scale more then hundreds millio…
We investigate the continuum and emission line properties of 4576 SDSS quasars as a function of their optical/UV SEDs. The optical/UV color distribution of our sample is roughly Gaussian, but with a red tail; we distinguish between 1) intrinsically blue (optically flat) quasars, 2) intrinsically red (optically steep) quasars, and 3) the 273 (6%) of our quasars whose continua are inconsistent with a single power-law and appear redder due to SMC-like dust reddening rather than synchrotron emission. The color distribution suggests that the population of moderately dust reddened broad-line quasars…
We present Chandra observations of 18 spectroscopically selected quasars, already known to be X-ray weak from previous ROSAT observations. All the sources but one are detected by Chandra, and spectral analysis suggests that most of them are intrinsically underluminous in the X-rays (by a factor from 3 to >100). These objects could represent a large population of quasars with a Spectral Energy Distribution different from that of standard blue quasars. We discuss the possibility that a significant fraction of the obscured AGN needed in Synthesis models of the X-ray background could be instead op…
We have used the Very Large Telescope (VLT) to obtain spectropolarimetry of the radio-loud, double-lobed broad absorption line (BAL) quasar PKS 0040-005. We find that the optical continuum of PKS 0040-005 is intrinsically polarized at 0.7% with an electric vector position angle nearly parallel to that of the large-scale radio axis. This result is naturally explained in terms of an equatorial scattering region seen at a small inclination, building a strong case that the BAL outflow is not equatorial. In conjunction with other recent results concerning radio-loud BAL quasars, the era of simply c…
The broad absorption line (BAL) features seen in a small fraction of quasar optical/UV spectra are attributed to bulk outflows away from the quasar core. Observational evidence suggests that dust plays a key role in these systems, although whether the inferred dust properties are a signature of orientation effects or whether they are indicative of an evolutionary sequence remains an outstanding issue. Submillimetre (submm) detections of BAL quasars (BALQSOs), which would clearly help to resolve this issue, have so far been sparse. This paper reports on new submm observations of seven BALQSOs. …
We study positional coincidences between gamma-ray bursts in the BATSE 3B catalogue and quasars/AGN taken from the Veron-Cetty & Veron compilation. For most classes of AGN, for BL Lac objects and for radio-loud quasars, we find no excess coincidences above random expectation, and we give upper limits for their burst emission rate. However, surprising evidence is found for a positional correlation between gamma-ray bursts and radio-quiet quasars. A total of 134 selected bursts with a position error radius <1.8d and the nearest and intrinsically brightest radio-quiet quasars (M_v<-24.2 and z<1.0…
With a redshift of z=5.5 and an optical blue magnitude M_B ~ -24.2 mag (~4.5 10^12 L_sun), RDJ030117+002025 is the most distant optically faint (M_B > -26 mag) quasar known. MAMBO continuum observations at lambda=1.2 mm (185 micrometer rest-frame) showed that this quasar has a far-IR luminosity comparable to its optical luminosity. We present near-infrared J- and K-band photometry obtained with NIRC on the Keck I telescope, tracing the slope of the rest frame UV spectrum of this quasar. The observed spectral index is close to the value of alpha_nu ~ -0.44 measured in composite spectra of optic…
We present short \chandra observations of twelve bright (i<18) z_em~1.5 quasars from the Sloan Digital Sky Survey chosen to have significantly redder optical colors than most quasars at the same redshift. Of the five quasars with optical properties most consistent with dust reddening at the quasar redshift, four show indirect evidence of moderate X-ray absorption (inferred N_H~10^22 cm^-2) with a dust-to-gas ratio <1% of the SMC value. The remaining seven objects show no evidence for even moderate intrinsic X-ray absorption. Thus, while optically red quasars are marginally more likely to show …
We report the discovery of a z=2.65 low-ionization iron broad absorption line quasar, FIRST J100424.9+122922, which is gravitationally-lensed by a galaxy at z~0.95. The object was discovered as part of a program to find very red quasars by matching the FIRST radio survey with the 2-MASS near-infrared survey. J100424.9+122922 is the second lensed system to be found in this program, suggesting that many gravitational lenses are probably missed from conventional optical quasar surveys. We have made a simple lens model and a rough estimate of the reddening in the immediate environment of the quasa…
We present results of a programme of multi-epoch, intra-night optical monitoring of a sample of non-blazar type AGN, which includes seven radio-quiet QSOs (RQQs) and an equal number of radio-loud, lobe-dominated quasars (LDQs), covering a redshift range from about 0.2 to 2.0. These two sets of optically bright and intrinsically luminous QSOs are well matched in the redshift-optical luminosity ($z - M_B$) plane. Our CCD monitoring covered a total of 61 nights with an average of 6.1 hours of densely sampled monitoring of just a single QSO per night, thereby achieving a typical detection threshol…
We present 0.5-8.0 keV Chandra observations of six bright quasars that represent extrema in quasar emission-line properties -- three quasars each with small and large blueshifts of the CIV emission line with respect to the systemic redshift of the quasars. Supplemented with seven archival Chandra observations of quasars that met our selection criteria, we investigate the origin of this emission-line phenomenon in the general context of the structure of quasars. We find that the quasars with the largest CIV blueshifts show evidence, from joint-spectral fitting, for intrinsic X-ray absorption (N…
We present 4-7 ks Chandra observations of 35 Broad Absorption Line (BAL) quasars from the Large Bright Quasar Survey, the largest sample of sensitive, 0.5-8.0 keV X-ray observations of this class of quasars to date. The limited ranges in both redshift (z=1.42-2.90) and UV luminosity (a factor of ~12) of the sample also make it relatively uniform. Of 35 targets, 27 are detected for a detection fraction of 77%, and we confirm previous studies that find BAL quasars to be generally X-ray weak. Five of the eight non-detections are known low-ionization BAL quasars, confirming reports of extreme X-ra…
We measure the spectral properties of a representative sub-sample of 187 quasars, drawn from the Parkes Half-Jansky, Flat-radio-spectrum Sample (PHFS). Quasars with a wide range of rest-frame optical/UV continuum slopes are included in the analysis: their colours range from 2 < B-K < 7. The median H-beta and [O III] emission-line equivalent widths of the red quasar sub-sample are a factor of ten weaker than those of the blue quasar sub-sample. Both the colours and the emission-line equivalent widths of the red quasars can be explained by the addition of a featureless red synchrotron continuum …
We have searched for redshifted absorption in the 21 cm line of neutral hydrogen toward `red quasars', which are extragalactic radio sources with a steep spectral drop between optical and infrared wavelengths. The success rate for detecting HI 21cm absorption toward a representative sample of such sources is 80%. This compares to the much lower success rate of 11% for detecting HI 21cm absorption associated with optically selected Mg II absorption line systems. The large neutral hydrogen column densities seen toward red quasars supports the hypothesis that these sources are reddened by dust, a…
We present BeppoSAX observations of three gamma-ray emitting quasars, namely 0836+710, 1510-089 and 2230+114. The three objects have been detected up to 100 keV showing extremely flat power-law spectra above 2 keV (energy index alpha_{2-10}=0.3-0.5). The soft X-ray spectrum of 0836+710 implies either an absorption column density higher than the galactic one or an intrinsically very hard slope (alpha_{0.1-1}=-0.2) below 1 keV. 1510-089 shows a soft excess, with the low energy spectrum steeper (alpha_{0.1-1}=1.6) than the high energy power-law. The results are discussed in the framework of curre…
We report on a detailed analysis of the correlation between the optical-UV (Lo) and X-ray (Lx) luminosities of quasars by means of Monte Carlo simulations, using a realistic luminosity function. We find, for a quasar population with an intrinsically constant, mean X-ray loudness alpha_ox, that the simulated alpha_ox - Lo relation can exhibit various `apparent' properties, including an increasing alpha_ox with Lo, similar to what has been found from observations. The determining factor for this behavior turns out to be the relative strength of the dispersions of the luminosities, i.e. their dev…
Historically the narrow line radio galaxies were thought to be intrinsically nonthermal, and without significant accretion. When the Unified Model came along the compelling observational motivation for this lost some force: some are found to be hidden broad line objects, and in principle that could be the case with all of them. The clear sign of a hidden quasar is a normal quasar spectrum in polarized (scattered) light. However that test requires a suitably placed "mirror." A more robust test is the high predicted mid-IR core luminosity reradiating from the obscuring matter. Cygnus A has this …
Spectral differences between lensed quasar image components are common. Since lensing is intrinsically achromatic, these differences are typically explained as the effect of either microlensing, or as light path time delays sampling intrinsic quasar spectral variability. Here we advance a novel third hypothesis: some spectral differences are due to small line-of-sight differences through quasar disk wind outflows. In particular, we propose that variable spectral differences seen only in component A of the widest separation lens SDSSJ1004+4112 are due to differential absorption along the sightl…
We have searched for redshifted neutral hydrogen 21cm absorption toward sources from the Stickel et al. `red quasar' sub-sample. Five of these red quasars have been searched for redshifted HI 21cm absorption to optical depth levels of a few percent, and four show strong absorption. This 80% success rate for the red quasars compares to the much lower success rate of only 11% for detecting HI 21cm absorption associated with optically selected Mg II absorption line systems. The large neutral hydrogen column densities seen toward the red quasars provide circumstantial evidence supporting the dust …
Hard X-ray surveys have uncovered a large population of heavily obscured AGN. They also reveal a population of quasars with moderate obscuration at both visible and X-ray wavelengths. We use Chandra selected samples of quasars from the ELAIS Deep X-ray Survey (EDXS) and CDF-N to investigate the obscuration towards the nuclei of moderately obscured AGN. We find an inverse correlation between the optical to X-ray flux ratio and the X-ray hardness ratio which can be interpreted as due to obscuration at visible and X-ray wavelengths. We present detailed optical and near-infrared data for a sample …
We present spectroscopic observations of the damped Ly-alpha absorber at redshift z=1.9342 seen in the spectrum of the quasar Q0151+048A. The redshift of the absorber is greater than the redshift of the quasar, so the system resembles the z(abs) ~ z(em) damped absorber at z=2.81 towards the quasar PKS0528-250. We have previously reported the detection of Ly-alpha emission from the latter absorber, one of only two damped absorbers for which Ly-alpha emission has unambiguously been detected. The resemblance between the PKS0528-250 and Q0151+048A systems is made closer by the detection of a weak …
We report on the discovery of a highly luminous, broad absorption line quasar at a redshift of $z=3.87$ which is positionally coincident, within one arcsecond, with the IRAS FSC source F08279+5255. A chance alignment of the quasar and the IRAS source is extremely unlikely and we argue that the optical and FIR flux are different manifestations of the same object. With an R-band magnitude of 15.2, and an IRAS 60$\mum$ flux of $0.51\jy$, APM 08279+5255 is (apparently) easily the most intrinsically luminous object known, with $ L_{Bol}\sim5\times10^{15}L_{\odot}}$. Imaging suggests that gravitatio…
In the course of the NIR/MIR AGN search combining the 6.7 mu ISOCAM Parallel Survey and 2MASS we have discovered 24 type-1 quasars about a third of which are too red to be discriminated by optical/UV search techniques. Here we report on a detailed case study of the reddest type-1 quasar of our sample (J2341) at redshift z=0.236 with M_K=-25.8 and J-K=1.95. We performed spectroscopy in the optical with VLT/FORS1 and in the MIR with Spitzer as well as NIR imaging with ISPI at CTIO. The optical and NIR observations reveal a star forming emission-line galaxy at the same redshift as the quasar with…
We present XMM-Newton X-ray spectra and optical photometry of four high redshift (z=2.96-3.77) quasars, [HB89] 0438-436, [HB89] 2000-330, [SP89] 1107+487 and RX J122135.6+280613; of these four objects the former two are radio-loud, the latter two radio-quiet. Model fits require only a power law with Galactic absorption in each case; additional intrinsic absorption is also needed for [HB89] 0438-436 and RX J122135.6+280613. The spectra are hard (Gamma \~1.7 for [HB89] 0438-436, [HB89] 2000-330 and ~1.4 for RX J122135.6+280613) with the exception of [SP89]~1107+487 which is softer (Gamma ~2.0); …
We investigate multicolour imaging data of a complete sample of 19 low redshift (z<0.2) quasar host galaxies. The sample was imaged in four optical (BVRi) and three near-infrared bands (JHK_s). Galaxy types, structural parameters and robust host galaxy luminosities are extracted for all bands by means of two-dimensional deblending of galaxy and nucleus. For the disc dominated fraction of host galaxies (Sa and later) the optical and optical-to-NIR colours agree well with the average colours of inactive galaxies of same type. The bulge dominated galaxies (E/S0) on the other hand appear a signifi…
Broad absorption line quasars (commonly termed BALQSOs) contain the most dramatic examples of AGN-driven winds. The high absorbing columns in these winds, ~10^24 cm^-2, ensure that BALQSOs are generally X-ray faint. This high X-ray absorption means that almost all BALQSOs have been discovered through optical surveys, and so what little we know about their X-ray properties is derived from very bright optically-selected sources. A small number of X-ray selected BALQSOs (XBALQSOs) have, however, recently been found in deep X-ray survey fields. In this paper we investigate the X-ray and rest-frame…
We combine results from ROSAT, Chandra, and multifrequency VLBA observations of the Compact Steep Spectrum quasar 3C 48. We infer that the X-ray spectrum of the nucleus is made up of a soft, variable, steep-spectrum component, and harder, power-law emission of slope consistent with the 1 GHz radio spectrum. The similarity of 3C 48's X-ray to radio ratio to that seen in core-dominated radio-loud quasars leads us to examine the possibility that the harder X-ray emission is inverse Compton radiation from the radio source, which is more than 99% resolved in our VLBA data. The weak (3 sigma) eviden…
Many models that seek to explain the origin of the unresolved X-ray background predict that Compton-thick Active Galactic Nuclei (AGNs) are ubiquitious at high redshift. However, few distant Compton-thick AGNs have been reliably identified to date. Here we present Spitzer-IRS spectroscopy and 3.6-70um photometry of a z=2.2 optically identified AGN (HDF-oMD49) that is formally undetected in the 2Ms Chandra Deep Field-North (CDF-N) survey. The Spitzer-IRS spectrum and spectral energy distribution of this object is AGN dominated, and a comparison of the energetics at X-ray wavelengths to those de…
We present the discovery of a high redshift, X-ray selected AGN by the Calan-Yale Deep Extragalactic Research (CYDER) survey: CXOCY J033716.7-050153, located at $z=4.61$, the second high redshift AGN discovered by this survey. Here, we present its optical, near-IR and X-ray properties and compare it with other optical and X-ray selected high redshift AGN. The optical luminosity of this object is significantly lower than most optically selected high redshift quasars. It also has a lower rest frame UV to X-ray emission ratio than most known quasars at this redshift. This mild deviation can be ex…
We have investigated the rest-frame optical and far-infrared properties of a sample of extremely bright candidate Lyman-break galaxies (LBG) identified in the Sloan Digital Sky Survey. Their high ultraviolet luminosities and lack of strong ultraviolet emission lines are suggestive of massive starbursts, although it is possible that they are more typical luminosity LBGs which have been highly magnified by strong gravitational lensing. Alternatively, they may be an unusual class of weak-lined quasars. If the ultraviolet and submillimetre properties of these objects mirror those of less luminous,…
We investigate the X-ray properties of the most luminous radio sources in the 3CR catalogue, in order to assess if they are similar to the most luminous radio quiet quasars, for instance in the X-ray normalization with respect to the optical luminosity, or in the distribution of the absorption column density. We have selected the (optically identified) 3CR radio sources whose 178-MHz monochromatic luminosity lies in the highest factor-of-three bin. The 4 most luminous objects had already been observed in X rays. Of the remaining 16, we observed with XMM-Newton 4 randomly chosen, optical type 1…
We discuss the properties of X-ray selected `red' AGN from the RIXOS sample. These are Seyfert 1 galaxies and quasars whose optical continua are relatively soft, ie. with an energy index, alpha_opt>2. There are 14 objects in the RIXOS sample which satisfy this criterion and they cover a range in redshift from z=0.08 to 1.27. Of these, two have characteristics which suggest that the continuum is intrinsically red, ie. an optical continuum which does not appear to have been significantly reddened by dust or to have contaminating light from the host galaxy. A further three objects show evidence o…
We present new spectroscopic observations of the southern radio galaxy PKS1549-79 (z =0.152).Despite the flat spectrum character of the radio emission from this source, our optical spectra show no sign of the broad permitted lines and non-stellar continuum characteristic of quasar nuclei and broad line radio galaxies. However, the high ionization forbidden lines, including [OIII]5007,4959, are unusually broad for a narrow line radio galaxy (FWHM 1350 km/s), and are blueshifted by 600 km/s relative to the low ionization lines such as[OII]3726,3729. The [OII] lines are also considerably narrower…
