Saved in:
Bibliographic Details
Main Authors: Teodori, M. A. Díaz, Bobrikova, A., Gnarini, A., Ursini, F., Forsblom, S. V., Poutanen, J., Salganik, A., Bianchi, S., Capitanio, F., Cocchi, M., Fabiani, S., Farinelli, R., Kaaret, P., Kajava, J. J. E., Matt, G., Ng, M., Ravi, S., Soffitta, P., Tarana, A., Zane, S.
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2604.18048
Tags: Add Tag
No Tags, Be the first to tag this record!
Table of Contents:
  • 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 coordinated observations of the atoll source 4U 1735-44, conducted with the Imaging X-ray Polarimetry Explorer (IXPE), NICER, and NuSTAR. Over the 2-8 keV energy range, we obtained a marginal detection of polarization with the polarization degree of $1.4\%\pm0.7\%$ and polarization angle of $-29^\circ\pm14^\circ$, corresponding to a $3σ$ upper limit on the polarization degree of 3.5\%. The best-fit model to describe the spectrum comprises a thermal component associated with the accretion disk, a Comptonized blackbody component, and a relativistic reflection component. From the reflection model, we infer a disk inclination of $\sim 40^\circ$. The spectroscopic and polarimetric properties of 4U 1735-44 are consistent with those observed in other atoll sources studied by IXPE, with its low polarization likely due to its low inclination.