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Simultaneous NICER and NuSTAR Observations of the Ultra-compact X-ray Binary 4U 1543-624
R. M. Ludlam, A. D. Jaodand, J. A. García +8
We present the first joint NuSTAR and NICER observations of the ultra-compact X-ray binary (UCXB) 4U 1543624 obtained in 2020 April. The source was at a luminosity of $L_{0.5-50…
A NICER View of a Highly-Absorbed Flare in GRS 1915+105
J. Neilsen, J. Homan, J. F. Steiner +4
After 26 years in outburst, the black hole X-ray binary GRS 1915+105 dimmed considerably in early 2018; its flux dropped sharply in mid-2019, and it has remained faint ever since.…
The destruction and recreation of the X-ray corona in a changing-look Active Galactic Nucleus
C. Ricci, E. Kara, M. Loewenstein +16
We present the drastic transformation of the X-ray properties of the active galactic nucleus 1ES 1927+654, following a changing-look event. After the optical/UV outburst the power-…
An Obscured, Seyfert-2-like State of the Stellar-mass Black Hole GRS 1915+105 Caused by Failed Disk Winds
J. M. Miller, A. Zoghbi, J. Raymond +13
We report on Chandra gratings spectra of the stellar-mass black hole GRS 1915+105 obtained during a novel, highly obscured state. As the source entered this state, a dense, massive…
A New Spin on an Old Black Hole: NuSTAR Spectroscopy of EXO 1846-031
Paul A. Draghis, Jon M. Miller, Edward M. Cackett +4
The black hole candidate EXO 1846-031 underwent an outburst in 2019, after at least 25 years in quiescence. We observed the system using \textit{NuSTAR} on August 3rd, 2019. The 3-…
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…
Supermassive black holes with high accretion rates in active galactic nuclei. XI. Accretion disk reverberation mapping of Mrk 142
Edward M. Cackett, Jonathan Gelbord, Yan-Rong Li +15
We performed an intensive accretion disk reverberation mapping campaign on the high accretion rate active galactic nucleus Mrk 142 in early 2019. Mrk 142 was monitored with the Nei…
Evidence for variability timescale dependent UV/X-ray delay in Seyfert 1 AGN NGC 7469
Mayukh Pahari, Ian M. McHardy, Federico Vincentelli +5
Using a month-long X-ray lightcurve from /PCA and 1.5 month long UV continuum lightcurves from spectra in 12201970 , we performed a detailed time-lag…
NICER-NuSTAR Observations of the Neutron Star Low-Mass X-ray Binary 4U 1735-44
R. M. Ludlam, E. M. Cackett, J. A. García +8
We report on the first simultaneous and observations of the neutron star (NS) low-mass X-ray binary 4U 173544, obtained in 2018 August. The source was at a lumi…
A rapid change in X-ray variability and a jet ejection in the black hole transient MAXI J1820+070
Jeroen Homan, Joe Bright, Sara E. Motta +13
We present Neutron Star Interior Composition Explorer X-ray and Arcminute Microkelvin Imager Large Array radio observations of a rapid hard-to-soft state transition in the black ho…
The Soft State of the Black Hole Transient Source MAXI J1820+070: Emission from the Edge of the Plunge Region?
A. C. Fabian, D. J Buisson, P. Kosec +18
The Galactic black hole X-ray binary MAXI J1820+070 had a bright outburst in 2018 when it became the second brightest X-ray source in the Sky. It was too bright for X-ray CCD instr…
Blueshifted absorption lines from X-ray reflection in IRAS 13224-3809
A. C. Fabian, C. S. Reynolds, J. Jiang +17
We explore a disc origin for the highly-blueshifted, variable absorption lines seen in the X-ray spectrum of the Narrow Line Seyfert 1 galaxy IRAS13224-3809. The blueshift correspo…
Modeling the upper kHz QPOs of 4U 1728-34 with X-ray reverberation
Benjamin M. Coughenour, Edward M. Cackett, Philippe Peille +1
While kilohertz quasi-periodic oscillations (kHz QPOs) have been well studied for decades since their initial discovery, the cause of these signals remains unknown, as no model has…
A dynamic black hole corona in an active galaxy through X-ray reverberation mapping
William N. Alston, Andrew C. Fabian, Erin Kara +18
X-ray reverberation echoes are assumed to be produced in the strongly distorted spacetime around accreting supermassive black holes. This signal allows us to spatially map the geom…