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Dive into the research topics where Ashley L. King is active.

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Featured researches published by Ashley L. King.


The Astrophysical Journal | 2013

The structure of the broad-line region in active galactic nuclei. I. Reconstructed velocity-delay maps

C. J. Grier; Bradley M. Peterson; K. Horne; Misty C. Bentz; Richard W. Pogge; K. D. Denney; G. De Rosa; Paul Martini; C. S. Kochanek; Ying Zu; B. J. Shappee; Robert J. Siverd; Thomas G. Beatty; S. G. Sergeev; Shai Kaspi; C. Araya Salvo; Jonathan C. Bird; D. J. Bord; G. A. Borman; Xiao Che; Chien-Ting J. Chen; Seth A. Cohen; Matthias Dietrich; V. T. Doroshenko; Yu. S. Efimov; N. Free; I. Ginsburg; C. B. Henderson; Ashley L. King; K. Mogren

We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C?120, and PG?2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the H? emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C?120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II??4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG?2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C?120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.


The Astrophysical Journal | 2013

THE REFLECTION COMPONENT FROM CYGNUS X-1 IN THE SOFT STATE MEASURED BY NuSTAR AND SUZAKU

John A. Tomsick; Michael A. Nowak; Michael C. Parker; Jon M. Miller; Andrew C. Fabian; Fiona A. Harrison; Matteo Bachetti; Didier Barret; Steven E. Boggs; Finn Erland Christensen; William W. Craig; Karl Forster; Felix Fürst; Brian W. Grefenstette; Charles J. Hailey; Ashley L. King; Kristin K. Madsen; L. Natalucci; Katja Pottschmidt; R. R. Ross; Daniel Stern; D. J. Walton; J. Wilms; William W. Zhang

The black hole binary Cygnus X-1 was observed in late 2012 with the Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku, providing spectral coverage over the ~1-300 keV range. The source was in the soft state with a multi-temperature blackbody, power law, and reflection components along with absorption from highly ionized material in the system. The high throughput of NuSTAR allows for a very high quality measurement of the complex iron line region as well as the rest of the reflection component. The iron line is clearly broadened and is well described by a relativistic blurring model, providing an opportunity to constrain the black hole spin. Although the spin constraint depends somewhat on which continuum model is used, we obtain ɑ_* > 0.83 for all models that provide a good description of the spectrum. However, none of our spectral fits give a disk inclination that is consistent with the most recently reported binary values for Cyg X-1. This may indicate that there is a >13° misalignment between the orbital plane and the inner accretion disk (i.e., a warped accretion disk) or that there is missing physics in the spectral models.


The Astrophysical Journal | 2013

REGULATION OF BLACK HOLE WINDS AND JETS ACROSS THE MASS SCALE

Ashley L. King; Jon M. Miller; John C. Raymond; Andrew C. Fabian; Christopher S. Reynolds; Kayhan Gültekin; Edward M. Cackett; S. W. Allen; Daniel Proga; Tim Kallman

We present a study of the mechanical power generated by both winds and jets across the black hole mass scale. We begin with the study of ionized X-ray winds and present a uniform analysis using Chandra grating spectra. The high-quality grating spectra facilitate the characterization of the outflow velocity, ionization, and column density of the absorbing gas. We find that the kinetic power of the winds, derived from these observed quantities, scales with increasing bolometric luminosity as log(Lwind,42/Cv) = (1.58 ±0.07)log(LBol,42) − (3.19 ±0.19). This suggests that supermassive black holes may be more efficient than stellar-mass black holes in launching winds, per unit filling factor, Cv. If the black hole binary (BHB) and active galactic nucleus (AGN) samples are fit individually, the slopes flatten to α BHB = 0.91 ±0.31 and α AGN = 0.63 ±0.30 (formally consistent within errors). The broad fit and individual fits both characterize the data fairly well, and the possibility of common slopes may point to common driving mechanisms across the mass scale. For comparison, we examine jet production, estimating jet power based on the energy required to inflate local bubbles. The jet relation is log(LJet,42) = (1.18 ±0.24)log(LBondi,42) − (0.96 ±0.43). The energetics of the bubble associated with Cygnus X-1 are particularly difficult to determine, and the bubble could be a background supernova remnant. If we exclude Cygnus X-1 from our fits, then the jets follow a relation consistent with the winds, but with a higher intercept, log(LJet,42) = (1.34 ±0.50)log(LBondi,42) − (0.80 ±0.82). The formal consistency in the wind and jet scaling relations, when assuming that LBol and LBondi are both proxies for mass accretion rate, suggests that a common launching mechanism may drive both flows; magnetic processes, such as magnetohydrodynamics and magnetocentrifugal forces, are viable possibilities. We also examine winds that are moving at especially high velocities, v> 0.01c. These ultra-fast outflows tend to resemble the jets more than the winds in terms of outflow power, indicating that we may be observing a regime in which winds become jets. A transition at approximately LBol ≈ 10 −2 LEdd is apparent when outflow power is plotted versus Eddington fraction. At low Eddington fractions, the jet power is dominant, and at high Eddington fractions, the wind power is dominant. This study allows for the total power from black hole accretion, both mechanical and radiative, to be characterized in a simple manner and suggests possible connections between winds and jets. X-ray wind data and jet cavity data will enable stronger tests.


Science | 2012

A 200-second quasi-periodicity after the tidal disruption of a star by a dormant black hole.

R. C. Reis; Josef M. Miller; Mark T. Reynolds; Kayhan Gültekin; Dipankar Maitra; Ashley L. King; Tod E. Strohmayer

Oscillating Black Hole The massive black holes that reside in the centers of galaxies can occasionally capture and tidally disrupt stars that wander too close. One such tidal disruption event was detected last year by the Swift satellite. Follow-up x-ray observations analyzed by Reis et al. (p. 949, published online 2 August; see the Perspective by McKinney) show quasi-periodic oscillations that suggest that an accretion disk formed around the black hole shortly after the tidal disruption event. This type of oscillation is commonly seen in the x-ray light from the much lighter black holes that result from the gravitational collapse of stars, but has been seen only once in a massive black hole residing in the center of a galaxy. Oscillations in x-ray emission from a galaxy’s central black hole imply that a disc formed after the hole captured a star. Supermassive black holes (SMBHs; mass is greater than or approximately 105 times that of the Sun) are known to exist at the center of most galaxies with sufficient stellar mass. In the local universe, it is possible to infer their properties from the surrounding stars or gas. However, at high redshifts we require active, continuous accretion to infer the presence of the SMBHs, which often comes in the form of long-term accretion in active galactic nuclei. SMBHs can also capture and tidally disrupt stars orbiting nearby, resulting in bright flares from otherwise quiescent black holes. Here, we report on a ~200-second x-ray quasi-periodicity around a previously dormant SMBH located in the center of a galaxy at redshift z = 0.3534. This result may open the possibility of probing general relativity beyond our local universe.


The Astrophysical Journal | 2012

A REVERBERATION LAG FOR THE HIGH-IONIZATION COMPONENT OF THE BROAD-LINE REGION IN THE NARROW-LINE SEYFERT 1 Mrk 335

C. J. Grier; Bradley M. Peterson; Richard W. Pogge; K. D. Denney; Misty C. Bentz; Paul Martini; S. G. Sergeev; Shai Kaspi; Ying Zu; C. S. Kochanek; Benjamin J. Shappee; K. Z. Stanek; C. Araya Salvo; Thomas G. Beatty; Jonathan C. Bird; D. J. Bord; G. A. Borman; Xiao Che; Chien-Ting J. Chen; Seth A. Cohen; Matthias Dietrich; V. T. Doroshenko; Yu. S. Efimov; N. Free; I. Ginsburg; C. B. Henderson; K. Horne; Ashley L. King; K. Mogren; M. Molina

We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 (NLS1) galaxy Mrk 335, collected over a 120 day span in the fall of 2010. From these data we measure the lag in the He II {lambda}4686 broad emission line relative to the optical continuum to be 2.7 {+-} 0.6 days and the lag in the H{beta}{lambda}4861 broad emission line to be 13.9 {+-} 0.9 days. Combined with the line width, the He II lag yields a black hole mass M{sub BH} = (2.6 {+-} 0.8) Multiplication-Sign 10{sup 7} M{sub Sun }. This measurement is consistent with measurements made using the H{beta}{lambda}4861 line, suggesting that the He II emission originates in the same structure as H{beta}, but at a much smaller radius. This constitutes the first robust lag measurement for a high-ionization line in an NLS1 galaxy and supports a scenario in which the He II emission originates from gas in virial motion rather than outflow.


The Astrophysical Journal | 2011

A Distinctive Disk-Jet Coupling in the Seyfert-1 Active Galactic Nucleus NGC 4051

Ashley L. King; Jon M. Miller; Edward M. Cackett; Andrew C. Fabian; Sera Markoff; Michael A. Nowak; Michael Rupen; Kayhan Gültekin; Mark T. Reynolds

We report on the results of a simultaneous monitoring campaign employing eight Chandra X-ray (0.5–10 keV) and six Very Large Array/Extended Very Large Array (8.4 GHz) radio observations of NGC 4051 over seven months. Evidence for compact jets is observed in the 8.4 GHz radio band; this builds on mounting evidence that jet production may be prevalent even in radio-quiet Seyferts. Assuming comparatively negligible local diffuse emission in the nucleus, the results also demonstrate an inverse correlation of Lradio ∝ L −0.72±0.04 X-ray . If the A configuration is excluded in the case where diffuse emission plays a significant role, the relation is still Lradio ∝ L −0.12±0.05 X-ray . Current research linking the mass of supermassive black holes and stellar-mass black holes in the “low/hard” state to X-ray luminosities and radio luminosities suggests a “fundamental plane of accretion onto black holes” that has a positive correlation of Lradio ∝ L 0.67±0.12 X-ray . Our simultaneous results differ from this relation by more than 11σ (6σ excluding the A configuration), indicating that a separate mode of accretion and ejection may operate in this system. A review of the literature shows that the inverse correlation seen in NGC 4051 is seen in three other black hole systems, all of which accrete at near 10% of their Eddington luminosity, perhaps suggesting a distinct mode of disk–jet coupling at high Eddington fractions. We discuss our results in the context of disks and jets in black holes and accretion across the black hole mass scale.


The Astrophysical Journal | 2015

High Resolution Chandra HETG spectroscopy of V404 Cygni in Outburst

Ashley L. King; Jon M. Miller; John C. Raymond; Mark T. Reynolds; Warren R. Morningstar

As one of the best-characterized stellar-mass black holes, with good measurements of its mass, distance and inclination, V404 Cyg is the ideal candidate to study Eddington-limited accretion episodes. After a long quiescent period, V404 Cyg underwent a new outburst in June 2015. We obtained two Chandra HETG exposures of 20 ksec and 25 ksec. Many strong emission lines are observed; the ratio of Si He-like triplet lines gives an estimate for the formation region distance of


The Astrophysical Journal | 2012

THE DISK-WIND-JET CONNECTION IN THE BLACK HOLE H 1743–322

Jon M. Miller; John C. Raymond; A. C. Fabian; Christopher S. Reynolds; Ashley L. King; Timothy R. Kallman; Edward M. Cackett; M. van der Klis; D. Steeghs

4\times10^{11}


Nature | 2017

The response of relativistic outflowing gas to the inner accretion disk of a black hole

M. L. Parker; Ciro Pinto; Andrew C. Fabian; Anne M. Lohfink; D. J. K. Buisson; W. N. Alston; E. Kara; Edward M. Cackett; Chia Ying Chiang; T. Dauser; Barbara de Marco; Luigi C. Gallo; J. Garcia; Fiona A. Harrison; Ashley L. King; Matthew J. Middleton; Jon M. Miller; G. Miniutti; Christopher S. Reynolds; P. Uttley; Ranjan Vasudevan; D. J. Walton; D. R. Wilkins; Abderahmen Zoghbi

cm, while the higher ionization Fe XXV He-like triplet gives an estimate of


The Astrophysical Journal | 2015

NuSTAR and Suzaku observations of the hard state in Cygnus X-1: locating the inner accretion disk

M. L. Parker; John A. Tomsick; Josef M. Miller; Kazutaka Yamaoka; Anne M. Lohfink; Martin A. Nowak; A. C. Fabian; W. N. Alston; S. E. Boggs; Finn Erland Christensen; William W. Craig; Felix Fürst; P. Gandhi; Brian W. Grefenstette; V. Grinberg; Charles J. Hailey; Fiona A. Harrison; E. Kara; Ashley L. King; D. Stern; D. J. Walton; J. Wilms; William W. Zhang

7\times10^9

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D. J. Walton

University of Cambridge

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Fiona A. Harrison

California Institute of Technology

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Finn Erland Christensen

Technical University of Denmark

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