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Abstract We examine the UV/X-ray properties of 1378 quasars in order to link empirical correlations to theoretical models of the physical mechanisms dominating quasars as a function of mass and accretion rate. The clarity of these correlations is improved when (1) using Civbroad emission line equivalent width (EQW) and blueshift (relative to systemic) values calculated from high signal-to-noise ratio reconstructions of optical/UV spectra and (2) removing quasars expected to be absorbed based on their UV/X-ray spectral slopes. In addition to using the traditional Civparameter space measures of CivEQW and blueshift, we define a “Civ∥ distance” along a best-fit polynomial curve that incorporates information from both Civparameters. We find that the Civ∥ distance is linearly correlated with both the optical-to-X-ray slope,αox, and broad-line HeiiEQW, which are known spectral energy distribution indicators, but does not require X-ray or high spectral resolution UV observations to compute. The Civ∥ distance may be a better indicator of the mass-weighted accretion rate, parameterized byL/LEdd, than the CivEQW or blueshift alone, as those relationships are known to break down at the extrema. Conversely, there is only a weak correlation with the X-ray energy index (Γ), an alternateL/LEddindicator. We find no X-ray or optical trends in the direction perpendicular to the Civdistance that could be used to reveal differences in accretion disk, wind, or corona structure that could be widening the CivEQW–blueshift distribution. A different parameter (such as metallicity) not traced by these data must come into play.
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Coordinated X-ray and UV absorption within the accretion disk wind of the active galactic nucleus PG 1126-041
Context.Accretion disk winds launched close to supermassive black holes (SMBHs) are a viable mechanism providing feedback between the SMBH and the host galaxy. Aims.We aim to characterize the X-ray properties of the inner accretion disk wind of the nearby active galactic nucleus PG 1126-041 and to study its connection with the UV-absorbing wind. Methods.We performed a spectroscopic analysis of eightXMM-Newtonobservations of PG 1126-041 taken between 2004 and 2015, using both phenomenological models and the most advanced accretion disk wind models available. For half of the data set, we were able to compare the X-ray analysis results with the results of quasi-simultaneous, high-resolution, spectroscopic UV observations taken with the Cosmic Origins Spectrograph on board theHubbleSpace Telescope. Results.The X-ray spectra of PG 1126-041 are complex and absorbed by ionized material, which is highly variable on multiple timescales, sometimes as short as 11 days. Accretion disk wind models can account for most of the X-ray spectral complexity of PG 1126-041, with the addition of massive clumps, represented by a partially covering absorber. Variations in column density (NH ∼ 5 − 20 × 1022cm−2) of the partially covering absorber drive the observed X-ray spectral variability of PG 1126-041. The absorption from the X-ray partially covering gas and from the blueshifted C IVtroughs appear to vary in a coordinated way. Conclusions.The line of sight toward PG 1126-041 offers a privileged view through a highly dynamic nuclear wind originating on inner accretion disk scales, making the source a very promising candidate for future detailed studies of the physics of accretion disk winds around SMBHs.
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- Award ID(s):
- 2107960
- PAR ID:
- 10541322
- Publisher / Repository:
- A&A
- Date Published:
- Journal Name:
- Astronomy & Astrophysics
- Volume:
- 679
- ISSN:
- 0004-6361
- Page Range / eLocation ID:
- A73
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1051/0004-6361/202244270
