Background quasars are potentially sensitive probes of galactic outflows provided that one can determine the origin of the absorbing material since both gaseous disks and strong bipolar outflows can contribute to the absorption cross-section. Using a dozen quasars passing near spectroscopically identified galaxies at $z\sim0.1$, we find that the azimuthal orientation of the quasar sight-lines with strong MgII absorption (with EW>0.3 Å) is bi-modal: about half the MgII sight-lines are aligned with the major axis and the other half are within 30deg. of the minor axis, showing that bipolar outflows contribute significantly to the MgII cross-section. This bi-modality is also present in the instantaneous star-formation rates (SFRs) of the hosts. For the sight-lines aligned along the minor axis, a simple bi-conical wind model is able to reproduce the observed MgII kinematics and the MgII dependence with impact parameter b, (EW $\propto b^{-1}$). Using our wind model, we can directly extract key wind properties such as the de-projected outflow speed $V_{out}$ of the cool material traced by MgII and the outflow rates. The outflow speeds are found to be 150-300 \kms, i.e. of the order of the circular velocity, and smaller than the escape velocity by a factor of ~2. The outflow rates are typically two to three times the instantaneous SFRs. Our results demonstrates how background quasars can be used to measure wind properties with high precision.
Gigaparsec scale alignments of the quasar optical polarization vectors have been proven to be robust against a scenario of contamination by the Galactic interstellar medium (ISM). This claim has been established by means of optical polarization measurements of the starlight surrounding the lines of sight of the 355 quasars for which reliable optical polarization measurements are available. In this paper, we take advantage of the full-sky and high quality polarization data released by the \textit{Planck} satellite to provide an independent, complementary, and up-to-date estimation of the contam…
Despite all the studies, the geometry of the wind at the origin of the blueshifted broad absorption lines (BAL) observed in nearly 20% of quasars still remains a matter of debate. We want to see if a two-component polar+equatorial wind geometry can reproduce the typical BAL profiles observed in these objects. We built a Monte Carlo radiative transfer code (called MCRT) to simulate the line profiles formed in a polar+equatorial wind in which the photons, emitted from a spherically symmetric core are resonantly scattered. Our goal is to reproduce typical C IV line profiles observed in BAL quasar…
We study the origin of absorption features on the blue side of the C IV broad emission line of the large-separation lensed quasar SDSS J1029+2623 at z_em ~ 2.197. The quasar images, produced by a foreground cluster of galaxies, have a maximum separation angle of ~ 22".5. The large angular separation suggests that the sight-lines to the quasar central source can go through different regions of outflowing winds from the accretion disk of the quasar, providing a unique opportunity to study the structure of outflows from the accretion disk, a key ingredient for the evolution of quasars as well as …
We propose the Apparent Shrinking Criterion (ASC) to interpret the spatial extent, R_w, of transmitted flux windows in the absorption spectra of high-z quasars. The ASC can discriminate between the two regimes in which R_w corresponds either to the physical size, R_HII, of the quasar HII region, or to the distance, R^{max}_w, at which the transmitted flux drops to =0.1 and a Gunn-Peterson (GP) trough appears. In the first case (HR regime), one can determine the IGM mean HI fraction, x_HI; in the second (PR regime), the value of R_w allows to measure the local photoionization rate and the local…
It has been proposed that the radio spectra of radio-quiet quasars is produced by free-free emission in the optically thin part of an accretion disc wind. An important observational constraint on this model is the observed X-ray luminosity. We investigate this constraint using a sample of PG radio-quiet quasars for which XMM-Newton EPIC spectra are available. Comparing the predicted and measured luminosities for 0.5, 2 and 5 keV, we conclude that all of the studied PG quasars require a large hydrogen column density absorber, requiring these quasars to be close to or Compton-thick. Such a large…
I describe two novel techniques originally devised to select strongly lensed quasar candidates in wide-field surveys. The first relies on outlier selection in optical and mid-infrared magnitude space; the second combines mid-infrared colour selection with GAIA spatial resolution, to identify multiplets of objects with quasar-like colours. Both methods have already been applied successfully to the SDSS, ATLAS and DES footprints: besides recovering known lenses from previous searches, they have led to new discoveries, including quadruply lensed quasars, which are rare within the rare-object clas…
We explore how the local environment is related to properties of active galactic nuclei (AGNs) of various luminosities. Recent simulations and observations are converging on the view that the extreme luminosity of quasars, the brightest of AGNs, is fueled in major mergers of gas-rich galaxies. In such a picture, quasars, the highest luminosity AGNs, are expected to be located in regions with a higher density of galaxies on small scales where mergers are more likely to take place. However, in this picture, the activity observed in low-luminosity AGNs is due to secular processes that are less de…
We present a brief description of a model for the broad emission line region (BELR) in quasars, which is supported by analysis of CIV and other emission lines in the spectra of high-z SDSS quasars. Specifically we consider a two-component BELR with a disk and wind where the relative strength of each component is a function of luminosity. The implications of such a model for our understanding of quasar outflows and estimates of their black hole masses and accretion rates are discussed.
The disk wind, which is powered by the radiation force due to spectral lines (line force), is studied for broad absorption line (BAL) quasars. We investigate the structure of the disk wind based on the non-hydrodynamic method and compare with wind properties inferred from X-ray observations of BAL quasars. In this paper, we apply the stellar wind theory to the initial condition (the mass outflow rate at the base of the wind). We found the funnel-shaped winds with a half opening angle of 50^{circ} for the case of epsilon=0.3-0.9 and M_{BH}=10^{7-8.5}M_odot, where epsilon is the Eddington ratio …
Approximately 20% of quasi-stellar objects (QSOs) exhibit broad, blue-shifted absorption lines in their ultraviolet spectra. Such features provide clear evidence for significant outflows from these systems, most likely in the form of accretion disk winds. These winds may represent the "quasar" mode of feedback that is often invoked in galaxy formation/evolution models, and they are also key to unification scenarios for active galactic nuclei (AGN) and QSOs. To test these ideas, we construct a simple benchmark model of an equatorial, biconical accretion disk wind in a QSO and use a Monte Carlo …
Broad absorption line (BAL) quasars probe the high velocity gas ejected by luminous accreting black holes. BAL variability timescales place constraints on the size, location, and dynamics of the emitting and absorbing gas near the supermassive black hole. We present multi-epoch spectroscopy of seventeen BAL QSOs from the Sloan Digital Sky Survey (SDSS) using the Fred Lawrence Whipple Observatory's 1.5m telescope's FAST Spectrograph. These objects were identified as BALs in SDSS, observed with Chandra, and then monitored with FAST at observed-frame cadences of 1, 3, 9, 27, and 81 days, as well …
A deep narrow-band survey for Ly-alpha emission carried out on the VLT-FORS2 has revealed 98 Ly-alpha candidates down to a flux limit of 4.e-18 erg/s/cm^2 in a volume of 5500 comoving Mpc^3 at z=2.4 centered on the hyperluminous quasar HE0109-3518. The properties of the detected sources in terms of their i) equivalent width distribution, ii) luminosity function, and iii) the average luminosity versus projected distance from the quasar, all suggest that a large fraction of these objects have been fluorescently "illuminated" by HE0109-3518. This conclusion is supported by comparison with detaile…
We investigate the extent and the properties of the MgII cool, low-density absorbing gas located in the halo and in the circum-galactic environment of quasars, using a sample of 31 projected quasar pairs with impact parameter pd<200kpc in the redshift range 0.5<z<1.6. In the transverse direction, we detect 18 MgII absorbers associated with the foreground quasars, while no absorption system originated by the gas surrounding the quasar itself is found along the line-of-sight. This suggests that the quasar emission induces an anisotropy in the absorbing gas distribution. Our observations indicate…
We quadruple the number of quasars known behind the Large Magellanic Cloud (LMC) from 55 (42 in the LMC fields of the third phase of the Optical Gravitational Lensing Experiment (OGLE)) to 200 by spectroscopically confirming 169 (144 new) quasars from a sample of 845 observed candidates in four ~3 deg^2 Anglo-Australian Telescope/AAOmega fields south of the LMC center. The candidates were selected based on their Spitzer mid-infrared colors, X-ray emission, and/or optical variability properties in the database of the OGLE microlensing survey. The contaminating sources can be divided into 115 yo…
We investigate the properties of the circumgalactic gas in the halo of quasar host galaxies from CIV absorption line systems. Optical spectroscopy of closely aligned pairs of quasars (projected distance \leq 200 kpc) obtained at the Gran Telescopio Canarias is used to investigate the distribution of the absorbing gas for a sample of 18 quasars at z \sim 2. We found that the detected absorption systems of EW \geq 0.3Ang associated with the foreground QSO are revealed up to 200 kpc from the center of the host galaxy. The structure of the absorbing gas is rather patchy with a covering fraction of…
We show that using mid-IR color selection to find active galactic nuclei (AGN) is as effective in dense stellar fields such as the Magellanic Clouds as it is in extragalactic fields with low stellar densities using comparisons between the Spitzer Deep, Wide-Field Survey data for the NOAO Deep Wide Field Survey Bootes region and the SAGE Survey of the Large Magellanic Cloud. We use this to build high purity catalogs of ~ 5000 AGN candidates behind the Magellanic Clouds. Once confirmed, these quasars will expand the available astrometric reference sources for the Clouds and the numbers of quasar…
We present absorption line analysis of the outflow in the quasar IRAS F04250-5718. Far-ultraviolet data from the Cosmic Origins Spectrograph onboard the Hubble Space Telescope reveal intrinsic narrow absorption lines from high ionization ions (e.g., C IV, N V, and O VI) as well as low ionization ions (e.g., C II and Si III). We identify three kinematic components with central velocities ranging from ~-50 to ~-230 km/s. Velocity dependent, non-black saturation is evident from the line profiles of the high ionization ions. From the non-detection of absorption from a metastable level of C II, we …
We report the detection of luminous CO(2-1), CO(3-2), and CO(4-3) emission in the strongly lensed high-redshift quasars B1938+666 (z=2.059), HE0230-2130 (z=2.166), HE1104-1805 (z=2.322), and B1359+154 (z=3.240), using the Combined Array for Research in Millimeter-wave Astronomy (CARMA). B1938+666 was identified in a `blind' CO redshift search, demonstrating the feasibility of such investigations with millimeter interferometers. These galaxies are lensing-amplified by factors of mu_L~11-170, and thus allow us to probe molecular gas in intrinsically fainter galaxies than currently possible witho…
We present a sample of 131 quasars from the Sloan Digital Sky Survey at redshifts 0.8<z<1.6 with double peaks in either of the high-ionization narrow emission lines [NeV]3426 or [NeIII]3869. These sources were selected with the intention of identifying high-redshift analogs of the z<0.8 active galactic nuclei (AGN) with double-peaked [OIII]5007 lines, which might represent AGN outflows or dual AGN. Lines of high-ionization potential are believed to originate in the inner, highly photoionized portion of the narrow line region (NLR), and we exploit this assumption to investigate the possible kin…
All quasar spectra show the same atomic features in the optical, UV, near-IR and soft X-rays over all of cosmic time, luminosity black hole mass and accretion rate. This is a puzzle. Here I show that it is possible that all of these atomic features can be accounted for by gas from an accretion disk driven by the three forms of radiation pressure: electron scattering, line driving and dust driving. The locations where they successfully drive an escaping wind, and those where they produce only a failed wind are both needed to produce the observed features.
An anomaly in the distribution of quasar magnitudes based on the SDSS survey, has been recently reported by Longo (2012). The angular size of this anomaly is of the order of $\rm \pm 15^o$ on the sky. A low surface brightness smooth structure in $γ$-rays, coincides with the sky location and extent of the quasar anomaly, and is close to the Northern component of a pair of $γ$-ray bubbles discovered in the \sl Fermi Gamma-ray Space Telescope \rm survey. Molecular clouds are thought to be illuminated by cosmic rays. I test the hypothesis that the magnitude anomaly in the quasar distribution, is d…
We study the long term time averaged kinetic luminosity, $\bar{Q}$, of the major flares of the Galactic microquasar GRS 1915+105 and the relationship to the intrinsic X-ray (bolometric) luminosity, $L_{\mathrm{bol}}$, and scale it to that of a complete sample of SDSS/FIRST FR II quasars. If the scale invariance hypothesis for black holes (BHs) holds then we show that the expected distribution in the $\bar{Q}$ - $L_{\mathrm{bol}}$ scatter plane of GRS 1915+105 is consistent with FR II quasars for distances D = 10.7 - 11 kpc. We compare the specific values of kinetic luminosity and $L_{\mathrm{b…
Luminous type-2 quasars in which the glow from the central black hole is obscured by dust are ideal targets for studying their host galaxies and the quasars' effect on galaxy evolution. Such feedback appears ubiquitous in luminous obscured quasars where high velocity ionized nebulae have been found. We present rest-frame yellow-band (~5000 Angstroms) observations using the Hubble Space Telescope for a sample of 20 luminous quasar host galaxies at 0.2 < z < 0.6 selected from the Sloan Digital Sky Survey. For the first time, we combine host galaxy observations with geometric measurements of quas…
The nature and energetics of feedback from thermal winds in quasars can be constrained via observations of the Sunyaev-Zeldovich Effect (SZE) induced by the bubble of thermal plasma blown into the intergalactic medium by the quasar wind. In this letter, we present evidence that we have made the first detection of such a bubble, associated with the hyperluminous quasar HE0515-4414. The SZE detection is corroborated by the presence of extended emission line gas at the same position angle as the wind. Our detection appears on only one side of the quasar, consistent with the SZE signal arising fro…
We review the main results from axisymmetric, time-dependent hydrodynamical simulations of radiation driven disk winds in AGN. We illustrate the capability of such simulations to provide useful insights into the three domains of observational astronomy: spectroscopy, time-variability, and imaging. Specifically, the synthetic line profiles predicted by the simulations resemble the broad absorption lines observed in quasars. The intrinsically time dependent nature of radiation driven disk winds that have been predicted by the simulations can be supported by a growing number of the observed drama…
The structure and kinematics of the broad line region (BLR) in quasars are still not well established. One popular BLR model is the disk-wind model that offers a geometric unification of a quasar based on the angle of viewing. We construct a simple kinematical disk-wind model with a narrow outflowing wind angle. The model is combined with radiative transfer in the Sobolev, or high velocity, limit. We examine how angle of viewing affects the observed characteristics of the emission line, especially the line widths and velocity offsets. The line profiles exhibit distinct properties depending on …
Various unification schemes interpret the complex phenomenology of quasars and luminous active galactic nuclei (AGN) in terms of a simple picture involving a central black hole, an accretion disc and an associated outflow. Here, we continue our tests of this paradigm by comparing quasar spectra to synthetic spectra of biconical disc wind models, produced with our state-of-the-art Monte Carlo radiative transfer code. Previously, we have shown that we could produce synthetic spectra resembling those of observed broad absorption line (BAL) quasars, but only if the X-ray luminosity was limited to …
In the context of the FLASHLIGHT survey, we obtained deep narrow band images of 15 $z\sim2$ quasars with GMOS on Gemini-South in an effort to measure Ly$α$ emission from circum- and inter-galactic gas on scales of hundreds of kpc from the central quasar. We do not detect bright giant Ly$α$ nebulae (SB~10$^{-17}$ erg s$^{-1}$ cm$^{-2}$ arcsec$^{-2}$ at distances >50 kpc) around any of our sources, although we routinely ($\simeq47$%) detect smaller scale <50 kpc Ly$α$ emission at this SB level emerging from either the extended narrow emission line regions powered by the quasars or by star-format…
A Potential Link between Nuclear Winds and Cold Gas Outflows on Kiloparsec Scales in Reionization-Era Quasars
Steward Observatory, University of Arizona（亚利桑那大学斯图尔德天文台）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学科维理天文与天体物理研究所）；Department of Astronomy, School of Physics, Peking University（北京大学物理学院天文学系）；Center for Astronomy and Astrophysics and Department of Physics, Fudan University（复旦大学天文与空间科学中心及物理系）；Department of Space, Earth, & Environment, Chalmers University of Technology（查尔姆斯理工大学空间、地球与环境系）；Department of Physics & Astronomy, University of California, Riverside（加州大学河滨分校物理与天文学系）；Department of Astronomy, University of Michigan（密歇根大学天文学系）；Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）
We study the geometry and the internal structure of the outflowing wind from the accretion disk of a quasar by observing multiple sightlines with the aid of strong gravitational lensing. Using Subaru/HDS, we performed high-resolution ($R$ $\sim$ 36,000) spectroscopic observations of images A and B of the gravitationally lensed quasar SDSS J1029+2623 (at $z_{em}$ $\sim$ 2.197) whose image separation angle, $θ$ $\sim$ 22$^{\prime\prime}\!\!$.5, is the largest among those discovered so far. We confirm that the difference in absorption profiles in the images A and B discovered by Misawa et al. (20…
A key to understanding quasar unification paradigms is the emission properties of broad absorption line quasars (BALQs). The fact that only a small fraction of quasar spectra exhibit deep absorption troughs blueward of the broad permitted emission lines provides a crucial clue to the structure of quasar emitting regions. To learn whether it is possible to discriminate between the BALQ and non-BALQ populations given the observed spectral properties of a quasar, we employ two approaches: one based on statistical methods and the other supervised machine learning classification, applied to quasar …
We present a detailed analysis of a very unusual sub-damped Lyman alpha (sub-DLA) system at redshift z=2.304 towards the quasar Q0453-423, based on high signal-to-noise (S/N), high-resolution spectral data obtained with VLT/UVES. With a neutral hydrogen column density of log N(HI)=19.23 and a metallicity of -1.61 as indicated by [OI/HI] the sub-DLA mimics the properties of many other optically thick absorbers at this redshift. A very unusual feature of this system is, however, the lack of any CIV absorption at the redshift of the neutral hydrogen absorption, although the relevant spectral regi…
We conduct kinematic analysis of the SDSS spectra of 568 obscured luminous quasars, with the emphasis on the kinematic structure of the [OIII]5007 emission line. [OIII] emission tends to show blueshifts and blue excess, which indicates that at least part of the narrow-line gas is undergoing an organized outflow. The velocity width containing 90% of line power ranges from 370 to 4780 km/sec, suggesting outflow velocities up to 2000 km/sec. The velocity width of the [OIII] emission is positively correlated with the radio luminosity among the radio-quiet quasars. We propose that radio emission in…
A search for emission lines in foreground galaxies in quasar spectra (z(gal) < z(QSO)) of the Sloan Digital Sky Survey (SDSS) data release 5 (DR5) reveals 23 examples of quasars shining through low redshift, foreground galaxies at small impact parameters (< 10 kpc). About 74,000 quasar spectra were examined by searching for narrow Hα emission lines at z < 0.38, at a flux level greater than 5 \times 10^-17 ergs cm^-2 s^-1, then confirming that other expected emission lines of the H II regions in the galaxy are detected. The galaxies were deblended from the quasar images to get colors and morpho…
We have performed stacking image analyses of galaxies over the Galactic extinction map constructed by Schlegel, Finkbeiner & Davis (1998). We select ~10^7 galaxies in total from the Sloan Digital Sky Survey (SDSS) DR7 photometric catalog. We detect clear signatures of the enhancement of the extinction in r-band, $ΔA_r$, around galaxies, indicating that the extinction map is contaminated by their FIR (far infrared) emission. The average amplitude of the contamination per galaxy is well fitted to $ΔA_r(m_r) = 0.64 \times 10^{0.17(18-m_r)}$ [mmag]. While this value is very small, it is directly a…
PDS 456 is a nearby (z=0.184), luminous (L_bol ~10^47 erg/s) type I quasar. A deep 190 ks Suzaku observation in February 2007 revealed the complex, broad band X-ray spectrum of PDS 456. The Suzaku spectrum exhibits highly statistically significant absorption features near 9 keV in the quasar rest--frame. We show that the most plausible origin of the absorption is from blue-shifted resonance (1s-2p) transitions of hydrogen-like iron (at 6.97 keV in the rest frame). This indicates that a highly ionized outflow may be present moving at near relativistic velocities (~0.25c). A possible hard X-ray …
We briefly describe some recent observational results, mainly at X-ray wavelengths, on the winds of luminous active galactic nuclei (AGNs). These winds likely play a significant role in galaxy feedback. Topics covered include (1) Relations between X-ray and UV absorption in Broad Absorption Line (BAL) and mini-BAL quasars; (2) X-ray absorption in radio-loud BAL quasars; and (3) Evidence for relativistic iron K BALs in the X-ray spectra of a few bright quasars. We also mention some key outstanding problems and prospects for future advances; e.g., with the International X-ray Observatory (IXO).
We perform halo occupation distribution (HOD) modeling of the projected two-point correlation function (2PCF) of high-redshift (z~1.2) X-ray-bright active galactic nuclei (AGN) in the XMM-COSMOS field measured by Allevato et al. The HOD parameterization is based on low-luminosity AGN in cosmological simulations. At the median redshift of z~1.2, we derive a median mass of (1.02+0.21/-0.23)x10^{13} Msun/h for halos hosting central AGN and an upper limit of ~10% on the AGN satellite fraction. Our modeling results indicate (at the 2.5-sigma level) that X-ray AGN reside in more massive halos compar…
We use the MusE GAs FLOw and Wind (MEGAFLOW) survey to study the kinematics of extended disk-like structures of cold gas around $z\approx1$ star-forming galaxies. The combination of VLT/MUSE and VLT/UVES observations allows us to connect the kinematics of the gas measured through MgII quasar absorption spectroscopy to the kinematics and orientation of the associated galaxies constrained through integral field spectroscopy. Confirming previous results, we find that the galaxy-absorber pairs of the MEGAFLOW survey follow a strong bimodal distribution, consistent with a picture of MgII absorption…
We present UV/optical spectropolarimetric modelling of the phenomenologically-based structure for quasars proposed by Elvis (2000). In this first paper of a series, we explore the continuum polarisation emerging from radiatively accelerated and bent winds that were vertically launched from the accretion disc in an active galactic nucleus (AGN). We simulate the radiative transfer occurring in Thomson scattering and dust extinction media over a range of morphological parameters and optical depths of the wind. We demonstrate that the wind geometry proposed by Elvis with a phenomenologically-deriv…
