MODELING HIGH-VELOCITY QSO ABSORBERS WITH PHOTOIONIZED MAGNETOHYDRODYNAMIC DISK WINDS

Journal Article · Wed Nov 10 00:00:00 EST 2010 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/723/2/L228· OSTI ID:21452679

Fukumura, Keigo ^[1]; Kazanas, Demosthenes ^[2]; Contopoulos, Ioannis ^[3]; Behar, Ehud ^[4]

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1. University of Maryland, Baltimore County (UMBC/CRESST), Baltimore, MD 21250 (United States)
2. Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
3. Research Center for Astronomy, Academy of Athens, Athens 11527 (Greece)
4. Department of Physics, Technion, Haifa 32000 (Israel)

We extend our modeling of the ionization structure of magnetohydrodynamic (MHD) accretion-disk winds, previously applied to Seyfert galaxies, to a population of quasi-stellar objects (QSOs) of much lower X-ray-to-UV flux ratios, i.e., smaller {alpha}{sub ox} index, motivated by UV/X-ray ionized absorbers with extremely high outflow velocities in UV-luminous QSOs. We demonstrate that magnetically driven winds ionized by a spectrum with {alpha}{sub ox} {approx_equal} -2 can produce the charge states responsible for C IV and Fe XXV/Fe XXVI absorption in wind regions with corresponding maximum velocities of v(C IV) {approx_lt}0.1c and v(Fe XXV) {approx_lt} 0.6c (where c is the speed of light) and column densities N {sub H} {approx} 10{sup 23}-10{sup 24} cm{sup -2}, in general agreement with observations. In contrast to the conventional radiation-driven wind models, high-velocity flows are always present in our MHD-driven winds but manifest in the absorption spectra only for {alpha}{sub ox} {approx_lt} -2, as larger {alpha}{sub ox} values ionize the wind completely out to radii too large to demonstrate the presence of these high velocities. We thus predict increasing velocities of these ionized absorbers with decreasing (steeper) {alpha}{sub ox}, a quantity that emerges as the defining parameter in the kinematics of the active galactic nucleus UV/X-ray absorbers.

• OSTI ID: 21452679
• Journal Information: Astrophysical Journal Letters, Vol. 723, Issue 2; Other Information: DOI: 10.1088/2041-8205/723/2/L228; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION
ABSORPTION SPECTRA
ACCRETION DISKS
CHARGE STATES
MAGNETOHYDRODYNAMICS
PHOTOIONIZATION
QUASARS
SEYFERT GALAXIES
SIMULATION
VELOCITY
X RADIATION
X-RAY GALAXIES
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTROMAGNETIC RADIATION
FLUID MECHANICS
GALAXIES
HYDRODYNAMICS
IONIZATION
IONIZING RADIATIONS
MECHANICS
RADIATIONS
SORPTION
SPECTRA