223 citations · 2.1k across the 67 of their papers we have counts for
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A Multi-Wavelength Picture of the Surprisingly Short 2024/25 Outburst from EXO 0748-676
Amy H. Knight, Lauren Rhodes, Noel Castro Segura +11
After sixteen years in quiescence, EXO 0748-676 unexpectedly returned to outburst in March 2024. However, in stark contrast to its previous outburst (1985 - 2008), EXO 0748-676 ret…
Studying the Variable Continuum and Emission Line Spectrum of 4U 1700-377 using NuSTAR's Stray Light
Colin J Bourque, McKinley C Brumback, Brian W Grefenstette +4
The high-mass X-ray binary 4U 1700-377 shows strong variation in brightness on timescales of hundreds of seconds due to accretion from a highly clumped stellar wind from the compan…
NuSTAR's Intentional Stray Light Observation of Scorpious X-1
S. Li, R. M. Ludlam, M. Sudha +8
We present the first spectral analysis of Scorpius X-1 (Sco X-1) using intentional stray light (SL) observations taken by NuSTAR. Unlike focused observations that have high telemet…
Flip-flop states in X-ray binaries and changing-state AGN
Thomas J. Maccarone, Jessie Runnoe, Gregoire Marcel +4
We show that the flip-flop transitions in X-ray binaries (rapid cycling between different spectral states which are sometimes seen near the global state transition) show a series o…
Disk warping and black hole X-ray binaries I. Tentative unification of low-frequency quasi-periodic oscillations
Gregoire Marcel, Samuel Turner, Benjamin Ricketts +6
X-ray binaries exhibit complex variability patterns studied in the power-spectrum. These include the broad-band noise (BBN) components and various types of narrow components called…
The 2025 Failed Outburst of IGR J17091-3624: Spectral Evolution and the Role of Ionized Absorbers
Oluwashina K. Adegoke, Javier A. Garcia, Guglielmo Mastroserio +15
IGR J17091-3624 is the only black hole X-ray binary candidate, aside from the well-studied black hole system GRS 1915+105, observed to exhibit a wide range of structured variabilit…
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…
Quasi-periodic variation during a fast X-ray outburst of a high-mass X-ray binary MAXI J0709-159 / LY CMa observed by NICER
Mutsumi Sugizaki, Tatehiro Mihara, Kohei Kobayashi +6
We report on a quasi-periodic variation at Hz during a fast X-ray outburst of a high-mass X-ray binary MAXI J0709159 / LY CMa observed by the Neutron-star interior compo…
IGR J17091-3624: Newly Formed Periodic Dips and Multiwavelength Activity During the 2025 Outburst
Zikun Lin, Yanan Wang, Shuyuan Wei +15
The black hole low-mass X-ray binary (LMXB) candidate IGR J17091-3624 experienced a hard-state-only outburst in 2025. In this paper, we show that IXPE detected a series of intermit…
Investigating MAXI J1752-457 with NuSTAR in the aftermath of a superburst
Sean N. Pike, Hitoshi Negoro, Douglas Buisson +5
We present two NuSTAR observations of the X-ray transient, MAXI J1752-457, following a superburst which was observed by MAXI/GSC in November, 2024. NuSTAR follow-up confirmed that…
Detection of a Type-C QPO during the soft-to-hard transition in Swift J1727.8-1613
Maïmouna Brigitte, Noel Castro Segura, Federico García +6
Timing analysis of accreting systems is key to probe the structure and dynamics around compact objects. In Black-Hole Low-Mass X-ray Binaries (BH LMXBs), the compact object accrete…
Flip-flop QPO changes during state transitions: a case study of GX339-4 and theoretical discussion
D. J. K. Buisson, G. Marcel, V. López-Barquero +3
We analyse the 2021 outburst from the black hole X-ray binary GX339-4 observed by NICER around the hard to soft transition, when the system exhibits flip-flops between two distinct…
Type I X-ray Burst Emission Reflected into the Eclipses of EXO 0748-676
Amy H. Knight, Jakob van den Eijnden, Adam Ingram +8
The neutron star X-ray binary, EXO 0748--676, was observed regularly by the Rossi X-ray Timing Explorer (RXTE) and XMM-Newton during its first detected outburst (1985 - 2008). Thes…
Simultaneous Optical and X-ray Detection of a Thermonuclear Burst in the 2024 Outburst of EXO 0748-676
Amy H. Knight, Lauren Rhodes, Douglas J. K. Buisson +5
The neutron star low-mass X-ray binary, EXO 0748--676, recently returned to outburst after a 16 year-long quiescence. Since its return, there has been a global effort to cap…
NICER Discovery that SRGA J144459.2-604207 is an Accreting Millisecond X-ray Pulsar
Mason Ng, Paul S. Ray, Andrea Sanna +17
We present the discovery, with the Neutron Star Interior Composition Explorer (NICER), that SRGA J144459.2-604207 is a 447.9 Hz accreting millisecond X-ray pulsar (AMXP), which und…
Investigating the Ultra-Compact X-ray Binary Candidate SLX 1735-269 with NICER and NuSTAR
David Moutard, Renee Ludlam, Malu Sudha +8
We present two simultaneous NICER and NuSTAR observations of the ultra-compact X-ray binary (UCXB) candidate SLX 1735-269 while the source was in two different spectral states. Usi…
Evidence for a dynamic corona in the short-term time lags of black hole X-ray binary MAXI J1820+070
Niek Bollemeijer, Phil Uttley, Arkadip Basak +19
In X-ray observations of hard state black hole X-ray binaries, rapid variations in accretion disc and coronal power-law emission are correlated and show Fourier-frequency-dependent…
Shedding far-ultraviolet light on the donor star and evolutionary state of the neutron-star LMXB Swift J1858.6-0814
N. Castro Segura, C. Knigge, J. H. Matthews +13
The evolution of accreting X-ray binary systems is closely coupled to the properties of their donor stars. As a result, we can constrain the evolutionary track a system is by estab…
X-ray and Radio Monitoring of the Neutron Star Low Mass X-ray Binary 1A 1744-361: Quasi Periodic Oscillations, Transient Ejections, and a Disk Atmosphere
Mason Ng, Andrew K. Hughes, Jeroen Homan +19
We report on X-ray (NICER/NuSTAR/MAXI/Swift) and radio (MeerKAT) timing and spectroscopic analysis from a three-month monitoring campaign in 2022 of a high-intensity outburst of th…
Simultaneous NICER and NuSTAR Observations of the Ultra-compact X-ray Binary 4U 0614+091
David Moutard, Renee Ludlam, Javier A. García +13
We present the first joint NuSTAR and NICER observations of the ultra-compact X-ray binary (UCXB) 4U 0614+091. This source shows quasi-periodic flux variations on the timescale of…
A shared accretion instability for black holes and neutron stars
F. M. Vincentelli, J. Neilsen, A. J. Tetarenko +20
Accretion disks around compact objects are expected to enter an unstable phase at high luminosity. One instability may occur when the radiation pressure generated by accretion modi…
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…
GRB 221009A: Discovery of an Exceptionally Rare Nearby and Energetic Gamma-Ray Burst
Maia A. Williams, Jamie A. Kennea, S. Dichiara +53
We report the discovery of the unusually bright long-duration gamma-ray burst (GRB), GRB 221009A, as observed by the Neil Gehrels Swift Observatory (Swift), Monitor of All-sky X-ra…
The Link Between Neutron Star X-ray Binaries and Spider Pulsars
Amy H. Knight, Adam Ingram, Jakob van den Eijnden +3
The discovery of transitional millisecond pulsars (tMSPs) provided conclusive proof that neutron star (NS) low-mass X-ray binaries (LMXBs) comprise part of the evolutionary pathway…