184 citations · 2.2k across the 43 of their papers we have counts for
42 papers
The Broadband View of the Bare Seyfert PG 1426+015: Relativistic Reflection, the Soft Excess and the Importance of Oxygen
D. J. Walton, A. Madathil-Pottayil, P. Kosec +8
We present results from a deep, coordinated - + observation of the type 1 Seyfert PG 1426+015, a source of particular interest as the most massive reverberati…
The NuSTAR Local AGN Distribution Survey (NuLANDS) I: Towards a Truly Representative Column Density Distribution in the Local Universe
Peter G. Boorman, Poshak Gandhi, Johannes Buchner +33
Hard X-ray-selected samples of Active Galactic Nuclei (AGN) provide one of the cleanest views of supermassive black hole accretion, but are biased against objects obscured by Compt…
The RS Oph outburst of 2021 monitored in X-rays with NICER
Marina Orio, Keith Gendreau, Morgan Giese +19
The 2021 outburst of the symbiotic recurrent nova RS Oph was monitored with the Neutron Star Interior Composition Explorer Mission (NICER) in the 0.2-12 keV range from day one afte…
Stellar wind variability in Cygnus X-1 from high-resolution excess variance spectroscopy with Chandra
Lucia K. Härer, Michael L. Parker, Ileyk El Mellah +5
Stellar winds of massive stars are known to be driven by line absorption of UV photons, a mechanism which is prone to instabilities, causing the wind to be clumpy. The clumpy struc…
UV/Optical disk reverberation lags despite a faint X-ray corona in the AGN Mrk 335
Erin Kara, Aaron J. Barth, Edward M. Cackett +37
We present the first results from a 100-day Swift, NICER and ground-based X-ray/UV/optical reverberation mapping campaign of the Narrow-Line Seyfert 1 Mrk 335, when it was in an un…
Physics Beyond the Standard Model with Future X-ray Observatories: Projected Constraints on Very-Light Axion-Like Particles with and
Júlia Sisk-Reynés, Christopher S. Reynolds, Michael L. Parker +2
Axion-Like Particles (ALPs) are well-motivated extensions of the Standard Model of Particle Physics and a generic prediction of some string theories. X-ray observations of bright A…
X-ray spectral and timing analysis of the Compton Thick Seyfert 2 galaxy NGC 1068
Indrani Pal, C. S. Stalin, M. L. Parker +2
We present the timing and spectral analysis of the Compton Thick Seyfert 2 active galactic nuclei NGC 1068 observed using {\it NuSTAR} and {\it XMM-Newton}. In this work for the fi…
Comparing Reflection and Absorption Models for the Soft X-ray Variability in the NLS1 AGN UGC 11763
Jiachen Jiang, Luigi C. Gallo, Dirk Grupe +1
We present a spectral analysis of two XMM-Newton observations of the narrow-line Seyfert 1 galaxy UGC 11763. UGC 11763 shows very different soft X-ray spectral shapes in the two ob…
The long-stable hard state of XTE J1752-223 and the disk truncation dilemma
Riley M. T. Connors, Javier A. Garcia, John Tomsick +10
The degree to which the thin accretion disks of black hole X-ray binaries are truncated during hard spectral states remains a contentious open question in black hole astrophysics.…
A New Emulated Monte Carlo Radiative Transfer Disk-Wind Model: X-Ray Accretion Disk-wind Emulator -- XRADE
G. A. Matzeu, M. Lieu, M. T. Costa +14
We present a new X-Ray Accretion Disk-wind Emulator (\textsc{xrade}) based on the 2.5D Monte Carlo radiative transfer code which provides a physically-motivated, self-consistent tr…
AGN X-ray Spectroscopy with Neural Networks
M. L. Parker, M. Lieu, G. A. Matzeu
We explore the possibility of using machine learning to estimate physical parameters directly from AGN X-ray spectra without needing computationally expensive spectral fitting. Spe…
High-density disc reflection spectroscopy of low-mass active galactic nuclei
L. Mallick, A. C. Fabian, J. A. García +13
The standard alpha-disc model predicts an anti-correlation between the density of the inner accretion disc and the black hole mass times square of the accretion rate, as seen in hi…
The X-ray Disk/Wind Degeneracy in AGN
M. L. Parker, G. A. Matzeu, J. H. Matthews +4
Relativistic Fe K emission lines from accretion disks and from disk winds encode key information about black holes, and their accretion and feedback mechanisms. We show that these…
Ionised Emission and Absorption in a Large Sample of Ultraluminous X-ray Sources
P. Kosec, C. Pinto, C. S. Reynolds +6
Most Ultraluminous X-ray sources (ULXs) are thought to be powered by super-Eddington accretion onto stellar-mass compact objects. Accretors in this extreme regime are naturally exp…
The nature of the extreme X-ray variability in the NLS1 1H 0707-495
M. L. Parker, W. N. Alston, L. Härer +11
We examine archival XMM-Newton data on the extremely variable narrow-line Seyfert 1 (NLS1) active galactic nucleus (AGN) 1H 0707-495. We construct fractional excess variance (Fvar)…
MAXI J1820+070 with NuSTAR II. Flaring during the hard to soft state transition with a long soft lag
D. J. K. Buisson, A. C. Fabian, P. Gandhi +6
We continue the analysis of NuSTAR data from the recent discovery outburst of MAXI J1820+070 (optical counterpart ASASSN-18ey), focussing on an observation including unusual flarin…
The first broadband X-ray view of the narrow line Seyfert 1 Ton S180
G. A. Matzeu, E. Nardini, M. L. Parker +15
We present joint \textit{XMM-Newton} and \textit{NuSTAR} observations of the `bare' narrow line Seyfert 1 Ton S180 (), carried out in 2016 and providing the first hard X-r…
The Origin of X-ray Emission in the Gamma-ray emitting Narrow-Line Seyfert 1 1H 0323+342
Sergio A. Mundo, Erin Kara, Edward M. Cackett +7
We present the results of X-ray spectral and timing analyses of the closest gamma-ray emitting narrow-line Seyfert 1 (-NLS1) galaxy, 1H 0323+342. We use observations from a rece…
General Physical Properties of Gamma-ray Emitting Narrow-Line Seyfert 1 Galaxies
Vaidehi S. Paliya, M. L. Parker, J. Jiang +4
We present the results of a detailed multi-wavelength study of a sample of sixteen narrow-line Seyfert 1 (NLSy1) galaxies known in -rays so far. This includes a focused X-ray sp…
NuSTAR observations of Mrk 766: distinguishing reflection from absorption
D. J. K. Buisson, M. L. Parker, E. Kara +14
We present two new NuSTAR observations of the narrow line Seyfert 1 (NLS1) galaxy Mrk 766 and give constraints on the two scenarios previously proposed to explain its spectrum and…
X-ray spectral variability of blazars using principal component analysis
Dennis Gallant, Luigi C. Gallo, Michael L. Parker
Principal Component Analysis (PCA) is applied to a variety of blazars to examine X-ray spectral variability. Data from nine different objects are analysed in two ways: long-term, w…
A high-density relativistic reflection origin for the soft and hard X-ray excess emission from Mrk 1044
Labani Mallick, William N. Alston, Michael L. Parker +7
We present the first results from a detailed spectral-timing analysis of a long (130 ks) XMM-Newton observation and quasi-simultaneous NuSTAR and Swift observations of the hi…
The 1.5 Ms Observing Campaign on IRAS 13224-3809: X-ray Spectral Analysis I
J. Jiang, M. L. Parker, A. C. Fabian +16
We present a detailed spectral analysis of the recent 1.5\,Ms XMM-Newton observing campaign on the narrow line Seyfert 1 galaxy IRAS~132243809, taken simultaneously with 500\,ks…
A Hard Look at the Neutron Stars and Accretion Disks in 4U 1636-53, GX 17+2, and 4U 1705-44 with
R. M. Ludlam, J. M. Miller, M. Bachetti +9
We present observations of neutron star (NS) low-mass X-ray binaries: 4U 1636-53, GX 17+2, and 4U 1705-44. We observed 4U 1636-53 in the hard state, with an Eddingt…