101,991 research outputs found
Variable X-ray absorption in the mini-broad absorption line quasar PG 1126-041
No full textWe present the results of a multi-epoch observational campaign on the mini-broad absorption line quasar (mini-BAL QSO) PG 1126-041 performed with XMM- Newton from 2004 to 2009. Time-resolved X-ray spectroscopy and simultaneous UV and X-ray photometry were performed on the most complete set of observations and on the deepest X-ray exposure of a mini-BAL QSO to date. Complex X-ray spectral variability, found on time scales of both months and hours, is best reproduced by means of variable and massive ionized absorbers along the line of sight. In the highest signal- to-noise observation, highly-ionized X-ray absorbing material outflowing much faster (υout ∼ 16500 km s−1) than the UV absorbing one (υout ∼ 5000 km s−1) is detected. This highly-ionized absorber is found to be variable on very short time scales of a few hours
HS 1700+6416: the first high redshift unlensed narrow absorption-line QSO showing variable high-velocity outflows
No full textWe present a detailed analysis of the X-ray emission of HS 1700+6416, a high-redshift (z = 2.7348) luminous quasar classified as a narrow absorption line (NAL) quasar on the basis of its SDSS spectrum. The source has been observed nine times by Chandra and once by XMM-Newton from 2000 to 2007. Long-term variability is clearly detected between the observations in the 2-10 keV flux, where it varies by a factor of three (~3-9 × 10-14 erg s-1 cm-2), and in the amount of neutral absorption (NH 3 × 10^23 cm-2), high ionization parameter (log ξ > 3.3 erg cm s-1) and a wide range of velocities (ΔV ~ 104 km s-1). This absorption line quasar is the fourth high-z quasar that displays X-ray signatures of variable high-velocity outflows, and among these, it is the only one that is not lensed. A rough estimate of the minimum kinetic energy carried by the wind of up to 18% Lbol, based on a biconical geometry of the wind, implies that the amount of energy injected into the outflow environment is large enough to produce effective mechanical feedback
Confirmation of and Variable Energy Injection by a Near-Relativistic Outflow in APM 08279+5255
No full textWe present results from multi-epoch spectral analysis of XMM-Newton and Chandra observations of the broad absorption line (BAL) quasar APM 08279+5255. Our analysis shows significant X-ray BALs in all epochs with rest-frame energies lying in the range of ~6.7-18 keV. The X-ray BALs and 0.2-10 keV continuum show significant variability on timescales as short as 3.3 days (proper time) implying a source size-scale of ~10 r_g, where r_g is the gravitational radius. We find a large gradient in the outflow velocity of the X-ray absorbers with projected outflow velocities of up to 0.76c. The maximum outflow velocity constrains the angle between the wind velocity and our line of sight to be less than ~22°. Based on our spectral analysis, we identify the following components of the outflow: (1) highly ionized X-ray absorbing material with an ionization parameter in the range of 2.9 <~log ξ <~ 3.9 (the units of ξ are erg cm s-1) and a column density of log NH ~ 23 (the units of NH are cm-2) outflowing at velocities of up to 0.76c; and (2) low-ionization X-ray absorbing gas with log NH ~ 22.8. We find a possible trend between the X-ray photon index and the maximum outflow velocity of the ionized absorber in the sense that flatter spectra appear to result in lower outflow velocities. Based on our spectral analysis of observations of APM 08279+5255 over a period of 1.2 yr (proper time), we estimate the mass-outflow rate and efficiency of the outflow to have varied between 16+12 -8 M sun yr-1 to 64+66 -40 M sun yr-1 and 0.18+0.15 -0.11 to 1.7+1.9 -1.2, respectively. Assuming that the outflow properties of APM 08279+5255 are a common property of most quasars at similar redshifts, our results then imply that quasar winds are massive and energetic enough to significantly influence the formation of the host galaxy, provide significant metal enrichment to the interstellar medium and intergalactic medium, and are a viable mechanism for feedback at redshifts near the peak in the number density of galaxy mergers
Linking the small-scale relativistic winds and the large-scale molecular outflows in the z = 1.51 lensed quasar HS 0810+2554
No full textWe present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the quadruply lensed z = 1.51 quasar HS 0810+2554 which provide useful insight on the kinematics and morphology of the CO molecular gas and the ∼2 mm-continuum emission in the quasar host galaxy. Lens modelling of the mm-continuum and the spectrally integrated CO(J = 3→2) images indicates that the source of the mm-continuum has an eccentricity of e ∼0.9 with a size of ∼1.6 kpc and the source of line emission has an eccentricity of e ∼0.7 with a size of ∼1 kpc. The spatially integrated emission of the CO(J = 2→1) and CO(J = 3→2) lines shows a triple peak structure with the outer peaks separated by Δv21 = 220 ± 19 km s-1 and Δv32 = 245 ± 28 km s-1, respectively, suggesting the presence of rotating molecular CO line emitting gas. Lensing inversion of the high spatial resolution images confirms the presence of rotation of the line emitting gas. Assuming a conversion factor of αCO = 0.8 M· (K km s-1 pc2)-1 we find the molecular gas mass of HS 0810+2554 to be MMol = (5.2 ± 1.5)/μ32 × 1010 M·, where μ32 is the magnification of the CO(J = 3→2) emission. We report the possible detection, at the 3.0-4.7σ confidence level, of shifted CO(J = 3→2) emission lines of high-velocity clumps of CO emission with velocities up to 1702 km s-1. We find that the momentum boost of the large-scale molecular wind is below the value predicted for an energy-conserving outflow given the momentum flux observed in the small-scale ultrafast outflow. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
A Chandra observation of the z=2.285 galaxy FSC 10214+4724: Evidence for a Compton-thick quasar?
No full textVariable X-ray absorption in mini-BAL QSOs
No full textWe 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 line of sight, compatible with radiatively-driven accretion disk wind models
XMM-Newton spectroscopy of highly polarized and luminous broad absorption line quasar CSO 755
No full textA Chandra snapshot survey of representative high-redshift radio-loud quasars from the Parkes-MIT-NRAO sample
No full textBibliographie Hilarion G. Petzold 1958 – 2009 mit Anhang als Einführung
No full textDieses Archiv enthält die Gesamtbibliographie der Werke des Autors nebst einiger Texte „Über H. G. Petzold“ im Schlussteil der Bibliographie sowie einen Anhang mit einer Einführung in die Architektur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author and some texts about H. G. Petzold, moreover an epilogue with an introduction to the architecture of the works in its epistemological structure and composition and as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2009-petzold-h-g-gesamtbibliographie-h-g-petzold-1958-2009-updating-november2009/peerReviewedpublishedVersio
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