SelectedWorks - Gary J. Ferland

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Selected Works of Gary J. Ferland

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About Gary J. Ferland

Present	Professor, University of Kentucky ‐ College of Arts and Sciences
Institution Organization Position Type Position Title Time Period to Options Current Position Affiliate my profile with this Institution

Astrophysics and Astronomy, Physical Processes, and Atomic, Molecular and Optical Physics

Theoretical astrophysics, Atomic & molecular physics, Quantitative spectroscopy, quasars, emission lines, Numerical simulations of non-equilibrium plasmas, and Chemical evolution of the cosmos

Department of Physics & Astronomy

177 Chem.-Phys. Building

University of Kentucky

505 Rose Street

Lexington KY 40506-0055

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Article

Space Telescope and Optical Reverberation Mapping Project. XI. Disk-Wind Characteristics ...

The Astrophysical Journal (2020)

Maryam Dehghanian, Gary J. Ferland, G. A. Kriss, B. M. Peterson, et al.

In 2014 the NGC 5548 Space Telescope and Optical Reverberation Mapping campaign discovered a two-month anomaly when variations in the ...

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Article

Radiative Cooling II: Effects of Density and Metallicity

Monthly Notices of the Royal Astronomical Society (2014)

Ye Wang, Gary J. Ferland, Matt Lykins, R. L. Porter, et al.

This work follows Lykins et al. discussion of classic plasma cooling function at low density and solar metallicity. Here, we ...

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Article

On the Observability of Optically Thin Coronal Hyperfine Structure Lines

The Astrophysical Journal (2014)

Marios Chatzikos, Gary J. Ferland, R. J. R. Williams and A. C. Fabian

We present CLOUDY calculations for the intensity of coronal hyperfine lines in various environments. We model indirect collisional and radiative ...

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Article

Interpreting the Ionization Sequence in AGN Emission-Line Spectra

Monthly Notices of the Royal Astronomical Society (2014)

Chris T. Richardson, James T. Allen, Jack A. Baldwin, Paul C. Hewett, et al.

We investigate the physical cause of the great range in the ionization level seen in the spectra of narrow-lined active ...

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Article

A Transition Mass for Black Holes to Show Broad Emission ...

Monthly Notices of the Royal Astronomical Society (2014)

Susmita Chakravorty, Martin Elvis and Gary J. Ferland

Although the supermassive (AGN) and stellar mass (BHBs) black holes have many properties in common, the broad emission lines (BELs) ...

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Article

Cold Gas Dynamics in Hydra-A: Evidence for a Rotating Disc

Monthly Notices of the Royal Astronomical Society (2014)

S. L. Hamer, A. C. Edge, A. M. Swinbank, J. B. R. Oonk, et al.

We present multifrequency observations of the radio galaxy Hydra-A (3C218) located in the core of a massive, X-ray luminous galaxy ...

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Article

Suppression of Dielectronic Recombination at Finite Densities

Journal of Physics: Conference Series (2014)

T. W. Gorczyca, D. Nikolić, N. R. Badnell and Gary J. Ferland

Density-dependent effective dielectronic recombination rate coefficients are determined in order to explore finite-density effects on the ionization balance of plasmas.

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Article

Atomic Data for S II—Toward Better Diagnostics of Chemical ...

The Astrophysical Journal (2013)

Romas Kisielius, Varsha P. Kulkarni, Gary J. Ferland, Pavel Bogdanovich, et al.

Absorption-line spectroscopy is a powerful tool used to estimate element abundances in both the nearby and distant universe. The accuracy ...

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Article

Effects of External Radiation Fields on Line Emission—Application to ...

The Astrophysical Journal (2013)

Marios Chatzikos, Gary J. Ferland, R. J. R. Williams, Ryan Porter, et al.

A variety of astronomical environments contain clouds irradiated by a combination of isotropic and beamed radiation fields. For example, molecular ...

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Article

Detecting the Rapidly Expanding Outer Shell of the Crab Nebula ...

The Astrophysical Journal (2013)

Xiang Wang, Gary J. Ferland, J. A. Baldwin, E. D. Loh, et al.

We present a range of steady-state photoionization simulations, corresponding to different assumed shell geometries and compositions, of the unseen postulated ...

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Article

Long-term Spectral Evolution of Tidal Disruption Candidates Selected by Strong ...

The Astrophysical Journal (2013)

Chen-Wei Yang, Ting-Gui Wang, Gary J. Ferland, Weimin Yuan, et al.

We present results of follow-up optical spectroscopic Multi-Mirror Telescope (MMT) observations of seven rare, extreme coronal line-emitting galaxies reported by ...

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Article

Studies of NGC 6720 with Calibrated HST/WFC3 Emission-line Filter ...

The Astronomical Journal (2013)

C. R. O'Dell, Gary J. Ferland, W. J. Henney and M. Peimbert

We have been able to compare with astrometric precision AstroDrizzle processed images of NGC 6720 (the Ring Nebula) made using ...

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Article

Classification and Analysis of Emission-Line Galaxies Using Mean Field Independent ...

Monthly Notices of the Royal Astronomical Society (2013)

James T. Allen, Paul C. Hewett, Chris T. Richardson, Gary J. Ferland, et al.

We present an analysis of the optical spectra of narrow emission-line galaxies, based on mean field independent component analysis (MFICA), ...

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Article

Suppression of Dielectronic Recombination due to Finite Density Effects

The Astrophysical Journal (2013)

D. Nikolić, T. W. Gorczyca, K. T. Korista, Gary J. Ferland, et al.

We have developed a general model for determining density-dependent effective dielectronic recombination (DR) rate coefficients in order to explore finite-density ...

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Article

Expanded Iron UTA Spectra—Probing the Thermal Stability Limits in ...

The Astrophysical Journal (2013)

Gary J. Ferland, R. Kisielius, F. P. Keenan, P. A. M. van Hoof, et al.

The Fe unresolved transition arrays (UTAs) produce prominent features in the ~15-17 Å wavelength range in the spectra of active ...

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Article

The Nature of the H2-Emitting Gas in the Crab Nebula

Monthly Notices of the Royal Astronomical Society (2013)

C. T. Richardson, J. A. Baldwin, Gary J. Ferland, E. D. Loh, et al.

Understanding how molecules and dust might have formed within a rapidly expanding young supernova remnant is important because of the ...

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Article

Radiative Cooling in Collisionally Ionized and Photoionized Plasmas

Monthly Notices of the Royal Astronomical Society (2013)

Matt Lykins, Gary J. Ferland, Ryan L. Porter, Peter A. M. van Hoof, et al.

We discuss recent improvements in the calculation of the radiative cooling in both collisionally ionized and photoionized plasmas. We are ...

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Article

Studies of NGC 6720 with Calibrated HST/WFC3 Emission-line Filter ...

The Astronomical Journal (2013)

C. R. O'Dell, Gary J. Ferland, W. J. Henney and M. Peimbert

We have performed a detailed analysis of the Ring Nebula (NGC 6720) using Hubble Space Telescope WFC3 images and derived ...

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Article

Studies of NGC 6720 with Calibrated HST/WFC3 Emission-line Filter ...

The Astronomical Journal (2013)

C. R. O'Dell, Gary J. Ferland, W. J. Henney and M. Peimbert

We have performed a detailed analysis of the electron temperature and density in the Ring Nebula using the calibrated Hubble ...

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Article

The 2013 Release of Cloudy

Revista Mexicana de Astronomia y Astrofisica (2013)

Gary J Ferland

This is a summary of the 2013 release of the plasma simulation code CLOUDY. CLOUDY models the ionization, chemical, and ...

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Article

Two-Component Structure of the Hβ Broad-line Region in Quasars ...

The Astrophysical Journal (2012)

Chen Hu, Jian-Min Wang, Luis C. Ho, Gary J. Ferland, et al.

We report on a spectral principal component analysis (SPCA) of a sample of 816 quasars, selected to have small Fe ...

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Article

Pumping Up the [N I] Nebular Lines

The Astrophysical Journal (2012)

Gary J. Ferland, W. J. Henney, C. R. O'Dell, R. L. Porter, et al.

The optical [N I] doublet near 5200 Å is anomalously strong in a variety of emission-line objects. We compute a ...

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Article

Residual Cooling and Persistent Star Formation Amid Active Galactic Nucleus ...

Monthly Notices of the Royal Astronomical Society (2012)

G. R. Tremblay, C. P. O'Dea, S. A. Baum, T. E. Clarke, et al.

New Chandra X-ray and Herschel Far-Infrared (FIR) observations enable a multiwavelength study of active galactic nucleus (AGN) heating and intracluster ...

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Article

The Curious Conundrum Regarding Sulfur Abundances in Planetary Nebulae

The Astrophysical Journal (2012)

R. B. C. Henry, Angela Speck, Amanda I. Karakas, Gary J. Ferland, et al.

Sulfur abundances derived from optical emission line measurements and ionization correction factors (ICFs) in planetary nebulae are systematically lower than ...

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Article

Ion-By-Ion Cooling Efficiencies

The Astrophysical Journal Supplement Series (2012)

Orly Gnat and Gary J. Ferland

We present ion-by-ion cooling efficiencies for low-density gas. We use Cloudy (version 10.00) to estimate the cooling efficiencies for each ...

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