Fred Hamann

Does the X-ray outflow quasar PDS 456 have a UV outflow at 0.3c?

The quasar PDS 456 (at redshift ~0.184) has a prototype ultra-fast outflow (UFO) measured in X-rays. This outflow is highly ionized with relativistic speeds, large total column densities log N_H(cm}^-2) > 23, and large kinetic energies that could be important for feedback to the host galaxy. A UV spectrum of PDS 456 obtained with the Hubble Space Telescope in 2000 contains one well-measured broad absorption line (BAL) at ~1346A (observed) that might be Ly-alpha at v ~ 0.06c or NV 1240 at v ~ 0.08c. However, we use photoionisation models and comparisons to other outflow quasars to show that these BAL identifications are problematic because other lines that should accompany them are not detected. We argue that the UV BAL is probably CIV 1549 at v ~ 0.30c. This would be the fastest UV outflow ever reported, but its speed is similar to the X-ray outflow and its appearance overall is similar to relativistic UV BALs observed in other quasars. The CIV BAL identification is also supported indirectly by the tentative detection of another broad CIV line at v ~ 0.19c. The high speeds suggest that the UV outflow originates with the X-ray UFO crudely 20 to 30 r_g from the central black hole. We speculate that the CIV BAL might form in dense clumps embedded in the X-ray UFO, requiring density enhancements of only >0.4 dex compared clumpy structures already inferred for the soft X-ray absorber in PDS 456. The CIV BAL might therefore be the first detection of low-ionisation clumps proposed previously to boost the opacities in UFOs for radiative driving.

Quasar Metal Abundances & Host Galaxy Evolution

Quasars signal a unique phase of galaxy evolution – when massive spheroids are rapidly being assembled, forming stars and growing their central super-massive black holes. Measurements of the metal abundances around quasars provide unique information about these complex evolutionary processes. Here we provide a brief review of the current status and implications of quasar abundance research. The central goal of quasar abundance studies is to understand the evolutionary relationship between quasars, super-massive black holes (SMBHs) and their host galaxies. We know that a close relationship exists because dormant SMBHs are not only common in galactic nuclei today, but their masses, M BH , scale directly with the mass of the surrounding galactic spheroids, M gal , (e.g., Tremaine et al. 2002). Whatever processes created the galactic spheroids must have also (somehow) created central SMBHs with commensurate mass. Luminous quasars represent the final major growth stage(s) of the most massive SMBHs inside the most massive galaxies. The quasar phase is very brief, of order 10 8 yr, but it coincides with a critical stage of SMBH–galaxy evolution when galactic spheroids are still rapidly being assembled and making stars. The energy output from accreting black holes might, in fact, regulate that star formation and thus lead naturally to the observed M BH – M gal correlation (Kauffmann & Haehnelt 2000, Granato et al. 2004). Quasar abundance studies can help us understand better the complex evolutionary relationship between SMBHs and their host galaxies. For example, how much star formation (how much conversion of the initial gas into stars) occurs in galactic spheroids before the visible quasar epoch? Did the major star-forming episodes occur before, during or after the final luminous stages of SMBH growth? Is the relative timing of these events consistent with quasars triggering star formation, shutting it down, or having no affect at all? How much do outflows during the quasar epoch contribute to the distribution of metals to the 1

Hunting for metals using XQ-100 Legacy Survey composite spectra

We investigate the NV absorption signal along the line of sight of background quasars, in order to test the robustness of the use of this ion as criterion to select intrinsic (i.e. physically related to the quasar host galaxy) narrow absorption lines (NALs). We build composite spectra from a sample of

Spectropolarimetry of high-redshift obscured and red quasars

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The gaseous environments of quasars: associate absorption lines with density and distance constraints

1000 CIV absorbers, covering the redshift range 2.55 10

Discovery of extreme [O iii] λ5007 Å outflows in high-redshift red quasars

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Resolving the X-ray obscuration in a low flux observation of the quasar PDS 456

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Extreme Red Quasars in SDSS-BOSS

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Host galaxies of binary AGN

are included in the composite spectrum. This result confirms that NV offers an excellent statistical tool to identify intrinsic systems. We exploit the stacks of 11 different ions to show that the gas in proximity to a quasar exhibits a considerably different ionization state with respect to gas in the transverse direction and intervening gas at large velocity separations from the continuum source. Indeed, we find a dearth of cool gas, as traced by low-ionization species and in particular by MgII, in the proximity of the quasar. We compare our findings with the predictions given by a range of Cloudy ionization models and find that they can be naturally explained by ionization effects of the quasar.

A ''WISE BOSS'':Finding the cosmic monsters in the mid-infrared lochs

Spectropolarimetry is a powerful technique that has provided critical support for the geometric unification model of local active galactic nuclei. In this paper, we present optical (rest-frame UV) Keck spectropolarimetry of five luminous obscured (Type 2) and extremely red quasars (ERQs) at z~2.5. Three objects reach polarization fractions of >10% in the continuum. We propose a model in which dust scattering is the dominant scattering and polarization mechanism in our targets, though electron scattering cannot be completely excluded. Emission lines are polarized at a lower level than is the continuum. This suggests that the emission-line region exists on similar spatial scales as the scattering region. In three objects we detect an intriguing 90 degree swing in the polarization position angle as a function of line-of-sight velocity in the emission lines of Ly-alpha, CIV and NV. We interpret this phenomenon in the framework of a geometric model with an equatorial dusty scattering region in which the material is outflowing at several thousand km/sec. Emission lines may also be scattered by dust or resonantly. This model explains several salient features of observations by scattering on scales of a few tens of pc. Our observations provide a tantalizing view of the inner region geometry and kinematics of high-redshift obscured and extremely red quasars. Our data and modeling lend strong support for toroidal obscuration and powerful outflows on the scales of the UV emission-line region, in addition to the larger scale outflows inferred previously from the optical emission-line kinematics.