50 citations · 275 across the 25 of their papers we have counts for
28 papers
Breaking the symmetry: X-ray polarization from a spreading layer on a tilted weakly magnetized neutron star
Anna Bobrikova, Alexandra Veledina, Juri Poutanen +1
When modeling the emission from an X-ray binary system, we often assume that the rotational axis of the compact object is aligned with that of the binary system. While often consid…
CHASE: Channel-Aligned Structure Exploitation for Geometry-Aware Model Engineering
Wei Wang, Wei Jiang, Ziran Liu
Geometric and Spectral Alignment (GSA) characterizes trained networks through spectral concentration, physical-channel alignment, support structure, and changes in singular bases.…
Peering through the dip: IXPE unveils the extended scattering environment of GX 13+1
Alessandro Di Marco, Fabio La Monaca, Luigi Stella +17
Neutron star low-mass X-ray binaries feature complex accretion geometries, often including an accretion disk corona or disk winds. Here, a study of the highly inclined dipping sour…
Pulse profile modelling of the 2024 outburst of the accreting millisecond pulsar SRGA J144459.2-604207
Bas Dorsman, Tuomo Salmi, Anna L. Watts +14
Pulse profile modelling via relativistic ray-tracing can constrain the system parameters of neutron stars, notably their mass and radius. Among these objects, accreting millisecond…
X-Ray Polarization from the Atoll 4U 1735-44 Suggests a Low Inclination
M. A. Díaz Teodori, A. Bobrikova, A. Gnarini +17
X-ray polarimetry is a new tool capable of probing the geometry of accretion onto weakly magnetized neutron stars. Here we present the first X-ray spectropolarimetric results from…
Discovery of High X-Ray Polarization from the Neutron Star Low-Mass X-Ray Binary Cyg X-2 in the Horizontal Branch
Andrea Gnarini, Swati Ravi, Philip Kaaret +17
We present results from simultaneous X-ray polarimetric and spectroscopic observations of the bright neutron star low-mass X-ray binary Cyg X-2, performed by the Imaging X-ray Pola…
Pulse profile modelling of the accretion-powered millisecond pulsar SAX J1808.4-3658 using NICER data from its 2019 and 2022 outbursts
Bas Dorsman, Tuomo Salmi, Anna L. Watts +5
Pulse profile modelling is a relativistic ray-tracing technique that has provided constraints on parameters, with a focus on mass and radius, of five rotation-powered millisecond p…
X-ray spectropolarimetric characterization of the Z-source GX 340+0 in the normal branch
Fabio La Monaca, Alessandro Di Marco, Francesco Coti Zelati +11
This study presents an X-ray spectropolarimetric characterisation of the Z-source GX 340+0 during the normal branch (NB) and compares it with that obtained for the horizontal branc…
IXPE view of the Sco-like source GX 349+2 in the normal branch
Fabio La Monaca, Anna Bobrikova, Juri Poutanen +6
We present a detailed spectropolarimetric study of the Sco-like Z-source GX 349+2, simultaneously observed with the Imaging X-ray Polarimetry Explorer (IXPE) and Nuclear Spectrosco…
X-ray spectro-polarimetry analysis of the weakly magnetized neutron star X-ray binary GX 9+1
Antonella Tarana, Fiamma Capitanio, Andrea Gnarini +14
We present an X-ray spectro-polarimetric study of the weakly magnetized neutron star low-mass X-ray binary GX 9+1, utilizing data from the Imaging X-ray Polarimetry Explorer (IXPE)…
X-ray Dips and Polarization Angle Swings in GX 13+1
Alessandro Di Marco, Fabio La Monaca, Anna Bobrikova +8
We present the result from the April 2024 observation of the low-mass X-ray binary GX 13+1 with the Imaging X-ray Polarimetry Explorer (IXPE), together with NICER and Swift-XRT coo…
Modelling polarized X-ray pulses from accreting millisecond pulsars with X-PSI, using different hot spot locations and shapes
Tuomo Salmi, Bas Dorsman, Anna L. Watts +7
We present an analysis of polarized X-ray pulses based on simulated data for accreting millisecond pulsars (AMPs). We used the open-source X-ray Pulse Simulation and Inference code…
X-ray spectro-polarimetric characterization of GX 340+0 in the horizontal branch: a highly inclined source?
Fabio La Monaca, Alessandro Di Marco, Renee M. Ludlam +4
We report the first detection of X-ray polarization in the horizontal branch for GX 340+0 as obtained by Imaging X-ray Polarimetry Explorer (IXPE). A polarization degree of 4.3%$\p…
First spectropolarimetric observation of the neutron star low-mass X-ray binary GX 3+1
Andrea Gnarini, Ruben Farinelli, Francesco Ursini +11
We report the first simultaneous X-ray spectropolarimetric observation of the bright atoll neutron star low-mass X-ray binary GX 3+1, performed by the Imaging X-ray Polarimetry Exp…
The IXPE View of Neutron Star Low-Mass X-ray Binaries
Francesco Ursini, Andrea Gnarini, Fiamma Capitanio +9
Low-mass X-ray binaries hosting weakly magnetized neutron stars (NS-LMXBs) are among the brightest sources in the X-ray sky. Since 2021, the Imaging X-ray Polarimetry Explorer (IXP…
Polarized radiation from the spreading layer of the weakly magnetized neutron stars
Anna Bobrikova, Juri Poutanen, Vladislav Loktev
Observations show that the X-ray emission of the accreting weakly magnetized neutron stars is polarized. Here, we develop a theoretical model, where we assume the emission of the a…
Parameter constraints for accreting millisecond pulsars with synthetic NICER data
Bas Dorsman, Tuomo Salmi, Anna L. Watts +10
Pulse profile modelling (PPM) is a technique for inferring mass, radius and hotspot properties of millisecond pulsars. PPM is now regularly used for analysis of rotation-powered mi…
X-ray spectropolarimetry of the bright atoll Serpens X-1
F. Ursini, A. Gnarini, S. Bianchi +11
We present simultaneous X-ray polarimetric and spectral observations of the bright atoll source Ser~X-1 carried out with the Imaging X-ray Polarimetry Explorer (IXPE), NICER, and N…
Discovery of Polarized X-Ray Emission from the Accreting Millisecond Pulsar SRGA J144459.2-604207
Alessandro Papitto, Alessandro Di Marco, Juri Poutanen +22
We report on the discovery of polarized X-ray emission from an accreting millisecond pulsar. During a 10-day-long coverage of the February 2024 outburst of SRGA J144459.2-604207, t…
New polarimetric study of the galactic X-ray burster GX 13+1
Anna Bobrikova, Alessandro Di Marco, Fabio La Monaca +3
Weakly magnetized neutron stars (WMNS) are complicated sources with challenging phenomenology. For decades, they have been studied via spectrometry and timing. It has been establis…
X-Ray Polarimetry of the Dipping Accreting Neutron Star 4U 1624-49
M. Lynne Saade, Philip Kaaret, Andrea Gnarini +98
We present the first X-ray polarimetric study of the dipping accreting neutron star 4U 162449 with the Imaging X-ray Polarimetry Explorer (IXPE). We report a detection of polari…
Discovery of a strong rotation of the X-ray polarization angle in the galactic burster GX 13+1
Anna Bobrikova, Sofia V. Forsblom, Alessandro Di Marco +106
Weakly magnetized neutron stars in X-ray binaries show complex phenomenology with several spectral components that can be associated with the accretion disk, boundary and/or spread…
X-Ray Polarized View on the Accretion Geometry in the X-Ray Binary Circinus X-1
John Rankin, Fabio La Monaca, Alessandro Di Marco +101
Cir X-1 is a neutron star X-ray binary characterized by strong variations in flux during its eccentric 16.6 days orbit. There are also strong variations in the spectral state…
Highly Significant Detection of X-Ray Polarization from the Brightest Accreting Neutron Star Sco X-1
Fabio La Monaca, Alessandro Di Marco, Juri Poutanen +116
The Imaging X-ray Polarimetry Explorer (IXPE) measured with high significance the X-ray polarization of the brightest Z-source Scorpius X-1, resulting in the nominal 2-8 keV energy…