Resolving structure within the iron line profile of Serpens X-1 with XRISM and NuSTAR

@misc{hall2026resolving,
  title = {{Resolving structure within the iron line profile of Serpens X-1 with XRISM and NuSTAR}},
  author = {Hayden Hall and Renee M. Ludlam and Edward Cackett and Jon M. Miller and Javier A. García},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.08904},
  eprint = {2609.08904},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.08904},
}

TY  - UNPB
TI  - Resolving structure within the iron line profile of Serpens X-1 with XRISM and NuSTAR
AU  - Hayden Hall
AU  - Renee M. Ludlam
AU  - Edward Cackett
AU  - Jon M. Miller
AU  - Javier A. García
PY  - 2026
DA  - 2026/09/08
PB  - arXiv
DO  - 10.48550/arxiv.2609.08904
UR  - https://arxiv.org/abs/2609.08904
AB  - We present the first simultaneous XRISM and NuSTAR observations of the neutron star low mass X-ray binary Serpens X-1. We perform spectral modeling on the joint observations of XRISM/Resolve, XRISM/Xtend, and NuSTAR, testing Comptonization and double thermal continuum model prescriptions. We find that a hybrid double thermal model adequately describes the underlying continuum of the source while the Comptonization models predict largely unphysical parameter values. We perform reflection modeling and confirm with tight constraints an inclination of 5^{\circ} \pm 1^{\circ} and inner disk radius of 6.6 \pm 0.6 Rg for the source. We show that the spectral resolution of XRISM/Resolve allows for the determination of a unique inner disk radius, which has the potential to constrain neutron star spin in other systems. We discuss discrepancies in spectral shape between XRISM/Resolve and NuSTAR above \sim 8 keV. We also present lightcurve and spectral analyses of 8 Type-I X-ray bursts that occurred during the observations.
ER  -