A broad absorption line outflow associated with the broad emission line region in the quasar SDSS J075133.35+134548.3

We report on the discovery of unusual broad absorption lines(BALs)in the bright quasar SDSS J075133.35+134548.3 at z~1,using archival and newly obtained optical and NIR spectroscopic data.The BALs are detected reliably in HeⅠ*λ3889,HeⅠ*λ10830 and tentatively in AlⅢ,MgⅡ.These BALs show complex velocity structures consisting of two major components:a high-velocity component(HV),with a blueshifted velocity range ofΔv_HV~9300--3500 km s^-1,which can be reliably detected in HeⅠ*λ10830,and tentatively in AlⅢand MgⅡ,whereas it is undetectable in HeⅠ*λ3889;and a low-velocity component(LV),withΔv_LV~3500--1800 km s^-1,is only detected in HeⅠ*λ3889 and HeⅠ*λ10830.With the BALs from different ions,the HV outflowing gas can be constrained to have a density of nH~10^10.3-10^11.4 cm^-3,a column density of NH~10²¹ cm^-2and an ionization parameter of U~10^-1.83-10^-1.72;inferring a distance of RHV~0.5 pc from the central continuum source with a monochromatic luminosityλLλ(5100)=7.0×10⁴⁵erg s^-1at 5100 A.This distance is remarkably similar to that of the normal broad line region(BLR)estimated from reverberation experiments,suggesting association of the BLR and the HV BAL outflowing gas.Interestingly,a blueshifted component is also detected in AlⅢand MgⅡbroad emission lines(BELs),and the AlⅢ/MgⅡof such a BEL component can be reproduced by the physical parameters inferred from the HV BAL gas.The LV BAL gas likely has a larger column density,a higher ionization level and hence a smaller distance than the HV BAL gas.Further spectroscopy with a high S/N ratio and broader wavelength coverage is needed to confirm this to shed new light on the possible connection between BALs and BELs.     

The sizes of broad emission line regions and black hole masses of double-peaked broad low-ionization emission line objects

In this paper, the sizes of the broad emission line regions (BLRs) and black hole (BH) masses of double-peaked broad low-ionization emission line emitters (DBP emitters) are compared using different methods: virial BH masses versus BH masses from stellar velocity dispersions, the size of BLRs from the continuum luminosity versus the size of BLRs from the accretion disc model. First, the virial BH masses of DBP emitters estimated by the continuum luminosity and linewidth of broad Hβ are about six times (a much larger value, if including another DBP emitters, of which the stellar velocity dispersions are traced by the linewidths of narrow emission lines) larger than the BH masses estimated from the relation   M _BH–σ  which is a more accurate relation to estimate BH masses. Second, the sizes of the BLRs of DBP emitters estimated by the empirical relation of   R _BLR– L _5100 Å  are about three times (a much larger value, if including another DBP emitters, of which the stellar velocity dispersions are traced by the linewidths of narrow emission lines) larger than the mean flux-weighted sizes of BLRs of DBP emitters estimated by the accretion disc model. The higher electron density of BLRs of DBP emitters would be the main reason which leads to smaller size of BLRs than the predicted value from the continuum luminosity.     

On the geometry of broad emission region in quasars

We study the geometry of the Hβ broad emission region by comparing the M _BH values derived from Hβ through the virial relation with those obtained from the host galaxy luminosity in a sample of 36 low-redshift  ( z ∼ 0.3)  quasars. This comparison lets us infer the geometrical factor f needed to deproject the line-of-sight velocity component of the emitting gas. The wide range of f values we found, together with the strong dependence of f on the observed linewidth, suggests that a disc-like model for the broad-line region is preferable to an isotropic model, both for radio-loud and radio-quiet quasars. We examined similar observations of the C  iv line and found no correlation in the width of the two lines. Our results indicate that an inflated disc broad-line region, in which the Carbon line is emitted in a flat disc while Hβ is produced in a geometrically thick region, can account for the observed differences in the width and shape of the two emission lines.     

Microlensing of broad absorption line quasars

The physical nature of the material responsible for the high-velocity broad absorption line (BAL) features seen in a small fraction of quasar spectra has been the subject of debate since their discovery. This has been especially compounded by the lack of observational probes of the absorbing region. In this paper we examine the role of 'microlenses' in external galaxies in the observed variability in the profiles of BALs in multiply imaged quasars. Utilizing realistic models for both the BAL region and the action of an ensemble of microlensing masses, we demonstrate that stars at cosmological distances can provide an important probe of the physical state and structure of material at the heart of these complex systems. Applying these results to the macrolensed BAL quasar system H1413+117, the observed spectral variations are readily reproduced, but without the fine-tuning requirements of earlier studies which employ more simplistic models.     

The broad iron line physics: summary and outlook

A brief overview of the ESAC/XMM‐Newton Science Operations Centre Workshop on “Variable and Broad Iron Lines around Black Holes” is presented. Following the relativistic disk‐line theory of accreting black holes, ASCA discovered such broad iron lines from several AGN. XMM‐Newton and Chandra confirmed the ASCA results, but also found more complexities. It was pointed out that poor modelling of the continuum may mimic broad iron line, if ionized absorbers are present. This degeneracy between the broad line and the continuum shape was shown to be resolved by separately determining the continuum and the reflection component with use of an accurate hard X‐ray spectrum obtained with Suzaku. As a result, the relativistic broad iron lines are now robust. Time variations of the primary continuum and the reflection component are often decoupled, the latter varying little. This is explained by the light bending model that applies in the region near to an extreme Kerr hole. The red‐ and/or blueshifted transient iron line features were found with XMM‐Newton, some of which revealed a possible quasi‐periodicity. Such transient features are important dynamical probes of the black hole vicinity. The remaining issues are briefly mentioned. Finally, there is no doubt that the broad line physics continues to be extremely important. Prospects for the future development are discussed, which justify large next‐generation missions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Hidden broad line regions and anisotropy in AGN

We discuss the recent advances made in the search for hidden broad line regions in Seyfert and Narrow Line Radio Galaxies (NLRG) using both spectropolarimetry and infrared spectroscopy/spectropolarimetry. Two important results which support the Grand Unification Theory are presented. In the first of these we report that the famous Seyfert 1 NGC 4151 has a scattered component to its broad line region, and is most likely an object where we view obliquely into its occulting torus. In the second, we show high signal to noise observations of scattered broad lines in the NLRG of 3C 234.     

The broad emission-line region in AGNs and quasars: The impact of variability studies

Coordinated observations of variability of the continuum and the emission-line luminosities (reverberation mapping) in AGNs and quasars have fundamentally altered our understanding of the broad-line regions in active galaxies. The constraints these observations impose on the models of the BLRs have been demonstrated here by an attempt to model the BLR of NGC5548, the most intensively monitored AGN. Two models of a BLR, with one having a power law radial distribution of density and the other a gaussian radial distribution, are described and the modelled line luminosities and centroid of the line response functions are presented. A self-consistent model is presented for the change in theCiv/Lyα ratio as the continuum luminosity changes. It is shown that BLR gas must be composed of a mixture of optically thin and optically thick gas and the proportion of thick and thin gas alters with the luminosity of the ionizing continuum. The observed centroid or the lag of a line, can be a function of the continuum luminosity. The variability of the profile of theCiv line in the spectrum of NGC5548 is investigated. This profile is extremely robust and is not significantly affected by changes in the ionizing continuum. Future models of the kinematics of the BLR clouds will have to be based on very stable cloud motions and include anisotropic line emission.     

The complex narrow line region in NGC 4151

We present new narrow band images of NGC 4151, taken in excellent seeing conditions with the 4.2-m William Herschel Telescope on La Palma. These reveal a wealth of detail that can be used to test models for the anisotropy of the narrow-line region.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

The infrared luminosity of the torus and the visibility of scattered broad line emission in Seyfert 2 galaxies

A number of studies have shown that the visibility of scattered broad emission lines in Seyfert 2 galaxies is strongly dependent on the IRAS     flux ratio, where those Seyfert 2 galaxies with 'warm' IRAS colours show polarized broad line emission. It is now clear that this effect is owing to the increasing dominance of the galactic rather than the active galactic nucleus (AGN) emission at 60 μm in less-luminous 'cool' Seyfert 2 galaxies. However, we present evidence that the 25-μm emission is a good measure of the AGN luminosity for most Seyfert 2 galaxies. Using this result, we show that the visibility of scattered broad line emission has a dependence on the AGN luminosity. The observations can be interpreted self-consistently if the scaleheight of the scattering zone varies with central source luminosity whilst the scaleheight of the obscuring torus is approximately constant.     

The fraction and mid-infrared properties of broad absorption line quasars from the Sloan Digital Sky Survey

We present the results of a study which uses a sample of 1822 Sloan Digital Sky Survey (SDSS) quasars with reliable Wide-field Infrared Survey Explorer (WISE) detections in the redshift range 1.7≤z≤4.38 to investigate the mid-infrared fraction of broad absorption line (BAL) quasars. The BAL quasars in the sample include both high-ionization BAL (HiBAL) quasars that show broad absorption from C?iv and low-ionization BAL (LoBAL) quasars that show additional broad absorption from Mg?ii. The fraction of C?iv BAL quasars with nonzero absorption index (AI) is found to be 38.7±1.2 %, in good agreement with that derived for the Two Micron All Sky Survey (2MASS) sample. The C?iv BAL quasar fractions remain constant with magnitude in the WISE 3.4 μm (W1) and 4.6 μm (W2) bands, and increase rapidly with decreasing magnitude in the WISE 12 μm (W3) and 22 μm (W4) bands. The nonzero AI fraction of 44.5±2.1 % determined in the WISE W4 band is more likely to represent the intrinsic BAL quasar fraction. No evidence that the fraction is a strong function of redshift is found. At 1.7≤z≤2.15, the overall mid-infrared LoBAL fraction is $3.3^{+0.6}_{-0.5}~\%$ and the fractions increase significantly with decreasing magnitude in all four of WISE bands. Moreover, it is found that the mean optical-to-WISE colors of BAL quasars are ?0.2 mag redder than that of non-BAL quasars, while the traditional (nonzero balnicity) BAL quasars are redder than the nontraditional BAL quasars by ?0.15 mag, which suggest a continuum of more reddening from non-BAL to nontraditional BAL to traditional BAL. No evidence that nontraditional BALs are a distinct class from traditional BALs is found. Finally, it is shown that the mean optical-to-WISE colors of LoBALs are ?0.4 mag redder than that of HiBALs at 1.7≤z≤2.15.     

The thermal structure of the magnetized solar transition region

The detailed thermal structure of the magnetized solar transition region, as measured by itsdifferential emission measure [DEM(T)], is unknown. Proposals have been made that envision a significant lower-temperature contribution to the energy balance from cross-field (ion) heat flux. In this paper, we describe a self-consistent, 2-D, MHD simulation (including the full effects of anisotropic thermal conduction) of a conceptual model due to Athay (1990). We display the detailed, irregular, thermal and magnetic structure of the transition region, and demonstrate that the predicted DEM agrees with observations, particularly in theT < 10⁵ K regime where previous theories had difficulty.     

Properties of radio-detected broad absorption line quasars from the Sloan Digital Sky Survey

We investigate the optical colors and radio morphologies of 214 broad absorption line (BAL) quasars with FIRST detections in the redshift range 1.68≤z≤4.93 drawn from the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) quasar catalog. The radio-detected SDSS BAL quasars are found to have Δ(g?i) colors significantly redder than their non-BAL counterparts, with a mean color difference of 0.52 mag, in good agreement with the O–E (roughly B–R) color difference between radio-selected BAL and non-BAL quasars in the FIRST Bright Quasar Survey (FBQS). The vast majority (～90 %) of the radio-detected BAL quasars are found to be core-only sources, most of which show compact radio morphologies, consistent with the morphological results for the FBQS sample. Moreover, within the FIRST-detected SDSS sample, BAL quasars with GB6 detections are found to span a wide range in radio spectral indices, indistinguishable from that of non-BAL quasars, indicating no special line of sight for the presence of BALs. The properties of the present SDSS sample are more consistent with the evolutionary model, in which BALs are at an early evolutionary stage of quasars.     

The structure of the IRAS05168+3634 star-forming region

Astrophysics and Space Science - Radioactive components of the interstellar medium provide an entirely-different and new aspect to the studies of the interstellar medium. Injected from sources of...     

Variations of broad emission lines from periodicity QSOs under the interpretation of supermassive binary black holes with misaligned circumbinary broad line regions

Quasars with periodic light curves are considered as candidates of supermassive binary black hole(BBH) systems.One way for further confirmations may be searching for other characteristic signatures,such as those in their broad emission lines(BELs),if any,which require a thorough understanding on the response of BELs to the BBH systems.In Ji et al.(2021),we have investigated the response of circumbinary broad line region(BLR) to the central active secondary black hole under the relativistic Doppler boosting(BBH-DB) and intrinsic variation(BBH-IntDB) dominant mechanisms for continuum variation by assuming the middle plane of the BLR aligned with the BBH orbital plane.In this paper,we explore how the BEL profiles vary when the BLR is misaligned from the BBH orbital plane with different offset angles under both the BBH-DB and BBH-IntDB scenarios.Given a fixed inclination angle of the BBH orbital plane viewed in edge-on and similar continuum light curves produced by the two scenarios,increasing offset angles make the initial opening angle of the circumbinary BLR enlarged due to orbital precession caused by the BBH system,especially for clouds in the inner region,which result in Lorentzlike BEL profiles for the BBH-DB model but still Gaussion-like profiles for the BBH-IntDB model at the vertical BLR case.The amplitude of profile variations decreases with increasing offset angles for the BBHDB scenario,while keeps nearly constant for the BBH-IntDB scenario,since the Doppler boosting effect is motion direction preferred but the intrinsic variation is radiated isotropically.If the circumbinary BLR is composed of a coplanar and a vertical components with their number of clouds following the mass ratio of the BBHs,then the bi-BLR features are more significant for the BBH-IntDB model that requires larger mass ratio to generate similar continuum variation than the BBH-DB model.     

The coronal and transition region temperature structure of a solar active region

Using measurements of EUV and X-ray spectral lines we derive the differential emission measure vs electron temperature T from the transition region to the corona of an active region (10⁵ T <5 × 10⁶ K). The total emission measure and radiative losses are of order 3 × 10⁴⁸ cm^–3 and 4 × 10²⁶ ergss^–1 respectively. The emission measure at T > 10⁶ K (i.e. that mainly responsible for the X-ray emission) is about 75% of the total. We also examine the use of Mg x 625 Å as an indicator of coronal electron density. A set of theoretical energy balance models of coronal loops in which the loop divergence is a variable parameter is presented and compared with the observations. Particular attention is given to the limitations inherent in any such comparison.     

Large-scale structure of galaxies in the Ophiuchus region

The large-scale structure around the Ophiuchus cluster of galaxies in the vicinity of the Galactic Centre ( l =05, b =95, cz =8500 km s⁻¹) is investigated on the basis of a galaxy survey and spectroscopic observations made for a 12°×17° area. The galaxy survey was performed using six ESO/SERC Sky Survey Atlas films, and 4021 galaxies were detected in total. Recession velocities were newly obtained for 179 galaxies to make the total number of galaxies in the survey area with known velocities 219.
In the distribution of bright galaxies, we identified seven new clumps of galaxies. Comparing the surface number density of bright galaxies with the Galactic extinction, which is estimated from the 100‐μm flux density in the IRAS Sky Survey Atlas, we demonstrate that the seven clumps are not spurious as a result of the inhomogeneity of the Galactic extinction. Among the seven clumps, two are found to be clusters and four to be groups on the basis of the histogram of recession velocities and the number of member galaxies. The Ophiuchus cluster, two newly identified clusters, and four groups are all concentrated at 9000 km s⁻¹. Field galaxies are also distributed centred at 8500 km s⁻¹. Hence field galaxies occupy a common three-dimensional region with galaxies in the clusters and groups, and altogether they form a large-scale structure of supercluster size. As opposed to the overdensity in the supercluster region, the mean number density of galaxies in the velocity range 0–5000 km s⁻¹ is only 25 per cent of the mean number density of the Universe, comparable with the density of the well-known Böotes void. Hence this nearby three-dimensional region in Ophiuchus is a void of galaxies also.