Past X-ray observations of the nearby luminous quasar PDS 456 (at z = 0.184) have revealed a wide-angle accretion disk wind with an outflow velocity of ∼−0.25c, as observed through observations of ...its blueshifted iron K-shell absorption line profile. Here we present three new XMM-Newton observations of PDS 456: one in 2018 September where the quasar was bright and featureless and two in 2019 September, 22 days apart, occurring when the quasar was five times fainter and where strong blueshifted lines from the wind were present. During the second 2019 September observation, three broad ( = 3000 km s−1) absorption lines were resolved in the high-resolution Reflection Grating Spectrometer spectrum that are identified with blueshifted O viii Ly , Ne ix He , and Ne x Ly . The outflow velocity of this soft X-ray absorber was found to be v/c = −0.258 0.003, fully consistent with an iron K absorber with v/c = −0.261 0.007. The ionization parameter and column density of the soft X-ray component (log = 3.4, NH = 2 × 1021 cm−2) outflow was lower by about 2 orders of magnitude when compared to the high-ionization wind at iron K (log = 5, NH = 7 × 1023 cm−2). Substantial variability was seen in the soft X-ray absorber between the 2019 observations, declining from NH = 1023 to 1021 cm−2 over 20 days, while the iron K component was remarkably stable. We conclude that the soft X-ray wind may originate from an inhomogeneous wind streamline passing across the line of sight that, due to its lower ionization, is located further from the black hole, on parsec scales, than the innermost disk wind.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted) We use gravitational microlensing to determine the size of the X-ray and optical emission regions of the quadruple lens system Q ...2237+0305. The optical half-light radius, log(R sub(1/2,)V /cm) = 16.41 + or - 0.18 (at lambda sub(rest) = 2018 Angstrom), is significantly larger than the observed soft, log(R sub(1/2,soft)/cm) = ... (1-1-3.5 keV in the rest frame), and hard, log(R sub(1/2,hard)/cm) = ... (3.5-21.5 keV in the rest frame), band X-ray emission. There is weak evidence that the hard component is more compact than the soft, with log(R sub(1/2,soft)/R sub(1/2,hard)) Asymptotically = to ... This wavelength-dependent structure agrees with recent results found in other lens systems using microlensing techniques, and favors geometries in which the corona is concentrated near the inner edge of the accretion disk. While the available measurements are limited, the size of the X-ray emission region appears to be roughly proportional to the mass of the central black hole.
Abstract
The analysis of the
Chandra
X-ray observations of the gravitationally lensed quasar RX J1131−1231 revealed the detection of multiple and energy-variable spectral peaks. The spectral ...variability is thought to result from the microlensing of the Fe K
α
emission, selectively amplifying the emission from certain regions of the accretion disk with certain effective frequency shifts of the Fe K
α
line emission. In this paper, we combine detailed simulations of the emission of Fe K
α
photons from the accretion disk of a Kerr black hole with calculations of the effect of gravitational microlensing on the observed energy spectra. The simulations show that microlensing can indeed produce multiply peaked energy spectra. We explore the dependence of the spectral characteristics on black hole spin, accretion disk inclination, corona height, and microlensing amplification factor and show that the measurements can be used to constrain these parameters. We find that the range of observed spectral peak energies of QSO RX J1131−1231 can only be reproduced for black hole inclinations exceeding 70° and for lamppost corona heights of less than 30 gravitational radii above the black hole. We conclude by emphasizing the scientific potential of studies of the microlensed Fe K
α
quasar emission and the need for more detailed modeling that explores how the results change for more realistic accretion disk and corona geometries and microlensing magnification patterns. A full analysis should furthermore model the signal-to-noise ratio of the observations and the resulting detection biases.
We present a promising new technique, the g-distribution method, for measuring the inclination angle (i), the innermost stable circular orbit (ISCO), and the spin of a supermassive black hole. The ...g-distribution method uses measurements of the energy shifts in the relativistic iron line emitted by the accretion disk of a supermassive black hole due to microlensing by stars in a foreground galaxy relative to the g-distribution shifts predicted from microlensing caustic calculations. We apply the method to the gravitationally lensed quasars RX J1131-1231 (zs = 0.658, zl = 0.295), QJ 0158-4325 (zs = 1.294, zl = 0.317), and SDSS 1004+4112 (zs = 1.734, zl = 0.68). For RX J1131−1231, our initial results indicate that rISCO 8.5 gravitational radii (rg) and i 55° (99% confidence level). We detect two shifted Fe lines in several observations, as predicted in our numerical simulations of caustic crossings. The current ΔE distribution of RX J1131-1231 is sparsely sampled, but further X-ray monitoring of RX J1131-1231 and other lensed quasars will provide improved constraints on the inclination angles, ISCO radii, and spins of the black holes of distant quasars.
We use gravitational microlensing of the four images of the z = 0.658 quasar RXJ 1131-1231 to measure the sizes of the optical and X-ray emission regions of the quasar. The (face-on) scale length of ...the optical disk at rest frame 400 nm is R{sub l}ambda{sub ,O} = 1.3 x 10{sup 15} cm, while the half-light radius of the rest frame 0.3-17 keV X-ray emission is R{sub 1/2,X} = 2.3 x 10{sup 14} cm. The formal uncertainties are factors of 1.6 and 2.0, respectively. With the exception of the lower limit on the X-ray size, the results are very stable against any changes in the priors used in the analysis. Based on the Hbeta line width, we estimate that the black hole mass is M{sub 1131} approx = 10{sup 8} M{sub sun}, which corresponds to a gravitational radius of r{sub g} approx = 2 x 10{sup 13} cm. Thus, the X-ray emission is emerging on scales of approx10r{sub g} and the 400 nm emission on scales of approx70r{sub g} . A standard thin disk of this size should be significantly brighter than observed. Possible solutions are to have a flatter temperature profile or to scatter a large fraction of the optical flux on larger scales after it is emitted. While our calculations were not optimized to constrain the dark matter fraction in the lens galaxy, dark matter-dominated models are favored. With well-sampled optical and X-ray light curves over a broad range of frequencies, there will be no difficulty in extending our analysis to completely map the structure of the accretion disk as a function of wavelength.
Abstract
We present results from a comprehensive study of ultrafast outflows (UFOs) detected in a sample of 14 quasars, 12 of which are gravitationally lensed, in a redshift range of 1.41–3.91, near ...the peak of the active galactic nucleus (AGN) and star formation activity. New XMM-Newton observations are presented for six of them, which were selected to be lensed and contain a narrow absorption line (NAL) in their UV spectra. Another lensed quasar was added to the sample, albeit already studied because it was not searched for UFOs. The remaining seven quasars of our sample are known to contain UFOs. The main goals of our study are to infer the outflow properties of high-
z
quasars, constrain their outflow induced feedback, study the relationship between the outflow properties and the properties of the ionizing source, and compare these results to those of nearby AGN. Our study adds six new detections (> 99% confidence) of UFOs at
z
> 1.4, almost doubling the current number of cases. Based on our survey of six quasars selected to contain a NAL and observed with XMM-Newton, the coexistence of intrinsic UV NALs and UFOs is found to be significant in >83% of these quasars suggesting a link between multiphase AGN feedback properties of the meso- and microscale. The kinematic luminosities of the UFOs of our high-
z
sample are large compared to their bolometric luminosities (median of
L
K
/
L
Bol
≳ 50%). This suggests they provide efficient feedback to influence the evolution of their host galaxies and that magnetic driving may be a significant contributor to their acceleration.
Utilizing 21 new Chandra observations as well as archival Chandra, ROSAT, and XMM-Newton data, we study the X-ray properties of a representative sample of 59 of the most optically luminous quasars in ...the universe (M sub(f) approximately -29.3 to -30.2) spanning a redshift range of z approximately 1.5 4.5. Our full sample consists of 32 quasars from the Sloan Digital Sky Survey (SDSS) Data Release 3 (DR3) quasar catalog, two additional objects in the DR3 area that were missed by the SDSS selection criteria, and 25 comparably luminous quasars at z unk 4. This is the largest X-ray study of such luminous quasars to date. By jointly fitting the X-ray spectra of our sample quasars, excluding radio-loud and broad absorption line (BAL) objects, we find a mean X-ray power-law photon index of Gamma = 1.92 super(+) sub(-) super(0) sub(0) super(.) sub(.) super(0) sub(0) super(9) sub(8) and constrain any neutral intrinsic absorbing material to have a mean column density of N sub(H) unk 2 x 10 super(21) cm super(-2). We find, consistent with other studies, that Gamma does not change with redshift, and we constrain the amount of allowed Gamma evolution for the most luminous quasars. Our sample, excluding radio-loud and BAL quasars, has a mean X-ray-to-optical spectral slope of alpha sub(ox) = -1.80 plus or minus 0.02, as well as no significant evolution of alpha sub(ox) with redshift. We also comment on the X-ray properties of a number of notable quasars, including an X-ray-weak quasar with several strong narrow absorption line systems, a mildly radio-loud BAL quasar, and a well-studied gravitationally lensed quasar.
The X-rays wind connection in PG 2112+059 Saez, C; Brandt, W N; Bauer, F E ...
Monthly Notices of the Royal Astronomical Society,
09/2021, Letnik:
506, Številka:
1
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
We study the connection between the X-ray and ultraviolet (UV) properties of the broad absorption line (BAL) wind in the highly X-ray variable quasar PG 2112+059 by comparing Chandra-ACIS ...data with contemporaneous UV HST/STIS spectra in three different epochs. We observe a correlation whereby an increase in the equivalent widths (EWs) of the BALs is accompanied by a redder UV spectrum. The growth in the BAL EWs is also accompanied by a significant dimming in soft X-ray emission (${\lesssim}2 \, \text{keV}$), consistent with increased absorption. Variations in the hard X-ray emission (${\gtrsim}2\, \text{keV}$) are only accompanied by minor spectral variations of the UV-BALs and do not show significant changes in the EW of BALs. These trends suggest a wind-shield scenario where the outflow inclination with respect to the line of sight is decreasing and/or the wind mass is increasing. These changes elevate the covering fraction and/or column densities of the BALs and are likely accompanied by a nearly contemporaneous increase in the column density of the shield.
The Chandra observations of several gravitationally lensed quasars show evidence for flux and spectral variability of the X-ray emission that is uncorrelated between images and is thought to result ...from the microlensing by stars in the lensing galaxy. We report here on the most detailed modeling of such systems to date, including simulations of the emission of the Fe K fluorescent radiation from the accretion disk with a general relativistic ray-tracing code, the use of realistic microlensing magnification maps derived from inverse ray-shooting calculations, and the simulation of the line detection biases. We use lensing and black hole parameters appropriate for the quadruply lensed quasar RX J1131−1231 (zs = 0.658, zl = 0.295) and compare the simulated results with the observational results. The simulations cannot fully reproduce the distribution of the detected line energies, indicating that some of the assumptions underlying the simulations are not correct, or that the simulations are missing some important physics. We conclude by discussing several possible explanations.
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