Transitional millisecond pulsars (tMSPs) bridge the gap between accreting neutron stars in low-mass X-ray binaries and rotation-powered millisecond radio pulsars, offering a unique laboratory to study the interplay between accretion and pulsar activity. These systems display a subluminous X-ray state characterized by rapid transitions between high, low, and flaring emission...
A never-ending competition takes place around rapidly spinning, weakly magnetized neutron stars in low-mass X-ray binaries. Inflowing matter spirals inward and, during outburst, is channeled along the neutron star’s magnetic field lines onto its magnetic poles, producing coherent X-ray pulsations. As the accretion rate declines, the rotating magnetosphere pushes back, halting accretion and...
The Galactic center (GC) is home to the largest known concentration of exotic X-ray sources ever identified in our Galaxy, including compact objects like cataclysmic variables (CVs) and low-mass X-ray binaries (LMXBs), as well as thousands of faint X-ray sources whose nature is unclear. Recent studies indicate that the X-ray populations in the innermost region of our Galaxy vary over...
This study examines the observational signatures of optically thick winds in thermonuclear X-ray bursts (XRBs). By combining the wind models from Herrera et al. (2023) with the burst models from José et al. (2010), we reconstruct theoretical X-ray light-curves and effective temperature evolution. Using the HEASOFT package, we simulate observational counterparts of said theoretical predictions,...
We investigate the impact of thermonuclear X-ray bursts on the persistent emission of the low-mass X-ray binary 4U 1636–536. Archival observations from XMM-Newton and INTEGRAL were analyzed through time-resolved X-ray spectroscopy of a burst simultaneously detected by four instruments: EPIC-pn, RGS, JEM-X, and ISGRI. The persistent emission was modeled using a combination of accretion disk,...
We present a detailed temporal analysis of a Type I X-ray burst from the neutron star low-mass X-ray binary (NS-LMXB) XTE J1810−189, observed on 27 April 2023 with the Neutron Star Interior Composition Explorer (NICER). The burst displays a rapid rise time of 2.55 s, followed by an exponential decay with a timescale of 7.5 s, resulting in a total burst duration of ~13 s. Type I X-ray bursts...
The simultaneous presence of kilohertz quasi-periodic oscillations (kHz QPOs) and relativistic Fe K emission lines in neutron star Low-Mass X-ray Binaries offers a unique opportunity to probe the innermost accretion flow. The frequency of a kHz QPO is thought to trace the orbital motion of matter in the inner accretion disk, while the Fe K line profile, shaped by relativistic broadening,...
GX 339–4 is a low-mass X-ray binary often used as an archetype, showing typical outburst behaviour. The source undergoes a full outburst every 2–3 years, passing through all known accretion states. We used NICER data to study the spectral-timing properties of the 2024 outburst of GX 339–4 and to compare them with the 2021 outburst. In particular we focused on rapid “flip-flop” transitions,...
The black hole candidate low-mass X-ray binary Swift J1727.8-1613 experienced one of the brightest outbursts ever observed in an X-ray binary in August 2023. Since then, this unique source has been observed across the entire electromagnetic spectrum. XMM-Newton monitored the low-mass X-ray binary for 3 days as it transitioned from the soft state – dominated by the multi-blackbody emission from...
NewAthena will advance our understanding of accretion onto stellar‑mass compact objects by enabling high‑throughput pointed X‑ray observations of low‑mass X‑ray binaries (LMXBs), including the elusive early stages of outbursts, through the combination of WFI wide‑field imaging/fast timing and X‑IFU high‑resolution spectroscopy. However, it is very difficult to predict when an LMXB will undergo...
The wealth and complexity of X-ray data provided by modern observatories has seen a dramatic improvement in recent years, in part due to new facilities like NICER and IXPE. This trend will accelerate further with new techniques like polarimetric timing, as well as future missions like NewAthena. On the other hand, the software modelling tools utilized by the community to model X-ray data are...
We are beginning to encounter computational and inference problems where complex models of atomic physics such as xillver must account for more and more parameters to properly model the absorption and emission lines present within our data. Coupled with the advent of XRISM, spectra tables must become unwieldingly large to compensate for the increase in energy resolution which makes it...
