activity
20232026
most citedDramatic Drop in the X-Ray Polarization of Swift J1727.81613 in the Soft Spectral State

45 citations · 102 across the 11 of their papers we have counts for

collaborators

11 papers

astro-ph.HE2026

Broad-band spectral-timing: simultaneous NICER and HXMT observations reveal an anticorrelation between the softest and hardest X-ray fluxes in MAXI J1820+070

Niek Bollemeijer, Phil Uttley, Bei You

Black hole X-ray binaries (BHXRBs) in the hard state show variable X-ray emission across a wide range of energies. Hard X-rays are thought to be produced through Compton-upscatteri…

astro-ph.HE2026

The strength of Type-C quasi-periodic oscillations in black hole X-ray binaries correlates with the jet inclination

F. M. Vincentelli, N. Bollemeijer, A. Veledina +10

X-ray quasi-periodic oscillations (QPOs) are a characteristic feature of low-mass X-ray binaries (LMXBs). These oscillations have been studied for decades and revealed a rich and c…

astro-ph.HE2026

Systematic assessment of disk truncation in the black hole X-ray binary Swift J1727.8-1613 using NICER

Ole König, James F. Steiner, Niek Bollemeijer +20

The 2023/24 NICER monitoring campaign of the 7 Crab bright black hole X-ray binary Swift J1727.8-1613 covered the outburst in almost all accretion states. High-quality data are ava…

astro-ph.HE2025

Covariance spectrum of MAXI J1820+070: On the nature of the Comptonizing flow

Shuai-Kang Yang, Bei You, Niek Bollemeijer +8

We present an analysis of the covariance spectrum of the black hole X-ray binary MAXI J1820+070 during its hard state. For the first time, we extend coherence and covariance studie…

astro-ph.HE2025

Long term variability of Cygnus X-1. IX. A spectral-timing comparison of Cygnus X-1 and MAXI J1820+070 in the hard state

Arkadip Basak, Phil Uttley, Niek Bollemeijer +11

Cygnus X-1 is a persistent, high-mass black hole X-ray binary (BHXRB) which in the hard state shows many similar properties to transient BHXRBs, along with intriguing differences,…

astro-ph.HE2025★ 3 cited

Variable QPO lags and reduced coherence between the disc and corona in MAXI J1820+070

Niek Bollemeijer, Phil Uttley

Quasi-periodic oscillations (QPOs) are observed in the hard state of many black hole X-ray binaries. Although their origin is unknown, they are strongly associated with the corona,…

astro-ph.HE2025★ 12 cited

A broadband spectral-timing study of QPOs in the bright black hole X-ray binary Swift J1727.8-1613

Niek Bollemeijer, Phil Uttley, Bei You

Swift J1727.8-1613 went into outburst in August 2023 and was one of the brightest black hole X-ray binaries (BHXRBs) in recent years, leading to extensive observing campaigns by NI…

astro-ph.HE2024★ 32 cited

Recovery of the X-ray polarisation of Swift J1727.81613 after the soft-to-hard spectral transition

J. Podgorný, J. Svoboda, M. Dovčiak +34

We report on the detection of X-ray polarisation in the black-hole X-ray binary Swift J1727.81613 during its dim hard spectral state by the Imaging X-ray Polarimetry Explorer (I…

astro-ph.HE2024★ 45 cited

Dramatic Drop in the X-Ray Polarization of Swift J1727.81613 in the Soft Spectral State

Jiří Svoboda, Michal Dovčiak, James F. Steiner +34

Black-hole X-ray binaries exhibit different spectral and timing properties in different accretion states. The X-ray outburst of a recently discovered and extraordinarily bright sou…

astro-ph.HE2023★ 6 cited

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…

astro-ph.HE2023★ 4 cited

Tracking the X-ray Polarization of the Black Hole Transient Swift J1727.8-1613 during a State Transition

Adam Ingram, Niek Bollemeijer, Alexandra Veledina +120

We report on an observational campaign on the bright black hole X-ray binary Swift J1727.81613 centered around five observations by the Imaging X-ray Polarimetry Explorer (IXPE)…