Constraining the white-dwarf mass in the intermediate polar IGR J17014-4306 using X-ray and optical spectroscopy
Abstract
Intermediate polars (IPs), a subclass of magnetic cataclysmic variables, often show discrepancies between white-dwarf (WD) mass measurements from X-ray spectral modeling and optical dynamical studies. We investigate the IP IGR J17014-4306. We performed a joint spectral analysis of NuSTAR observations combined with archival XMM-Newton and Swift data, modeling the broad-band X-ray spectrum with a multi-temperature cooling-flow model. Additionally, we obtained time-resolved optical spectroscopy with the SOAR telescope to measure the radial velocity of the donor star and constrain the system's orbital parameters. The X-ray spectral analysis reveals a very high post-shock plasma temperature of kTmax=50−8+11 keV, corresponding to a WD mass of MWD=0.94−0.07+0.09 M⊙. We also fitted the NuSTAR spectrum above 10 keV with the ipolar30KK model, obtaining MWD=0.88−0.12+0.14 M⊙. Our optical spectroscopy yields a radial-velocity semi-amplitude for the companion star of K2=165±4 km s−1 and an optical mass function of f(M)=0.249±0.018 M⊙. Combined with the eclipse geometry and the WD mass estimate from the X-ray models, these results favor a high mass ratio, 0.76≲ q≲0.95, and a donor-star mass of approximately 0.67≲ M2/M⊙≲0.89. In the limiting case of q=1, the WD mass has an upper limit of 1.14 M⊙. Together with the X-ray measurements, this indicates a relatively massive WD. The lack of an independent measurement of the WD dynamical mass leaves it unclear whether the dynamical mass is consistent with the X-ray measurements or whether the X-ray mass is underestimated, as has been found for other IPs. Thus, our constraints make IGR J17014-4306 an important system for improving our understanding of IPs.
Versions
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BibTeX
@misc{souza2026constraining,
title = {{Constraining the white-dwarf mass in the intermediate polar IGR J17014-4306 using X-ray and optical spectroscopy}},
author = {D. C. Souza and M. P. Diaz and A. S. Oliveira and G. J. M. Luna and C. V. Rodrigues and M. Reynolds and N. Palivanas and I. J. Lima and J. Mikołajewska and M. Orio},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.06785},
eprint = {2611.06785},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.06785},
}
RIS
TY - UNPB
TI - Constraining the white-dwarf mass in the intermediate polar IGR J17014-4306 using X-ray and optical spectroscopy
AU - D. C. Souza
AU - M. P. Diaz
AU - A. S. Oliveira
AU - G. J. M. Luna
AU - C. V. Rodrigues
AU - M. Reynolds
AU - N. Palivanas
AU - I. J. Lima
AU - J. Mikołajewska
AU - M. Orio
PY - 2026
DA - 2026/11/04
PB - arXiv
DO - 10.48550/arxiv.2611.06785
UR - https://arxiv.org/abs/2611.06785
AB - Intermediate polars (IPs), a subclass of magnetic cataclysmic variables, often show discrepancies between white-dwarf (WD) mass measurements from X-ray spectral modeling and optical dynamical studies. We investigate the IP IGR J17014-4306. We performed a joint spectral analysis of NuSTAR observations combined with archival XMM-Newton and Swift data, modeling the broad-band X-ray spectrum with a multi-temperature cooling-flow model. Additionally, we obtained time-resolved optical spectroscopy with the SOAR telescope to measure the radial velocity of the donor star and constrain the system's orbital parameters. The X-ray spectral analysis reveals a very high post-shock plasma temperature of kT_max=50_−8^+11 keV, corresponding to a WD mass of M_WD=0.94_−0.07^+0.09 M_⊙. We also fitted the NuSTAR spectrum above 10 keV with the ipolar30KK model, obtaining M_WD=0.88_−0.12^+0.14 M_⊙. Our optical spectroscopy yields a radial-velocity semi-amplitude for the companion star of K_2=165±4 km s^−1 and an optical mass function of f(M)=0.249±0.018 M_⊙. Combined with the eclipse geometry and the WD mass estimate from the X-ray models, these results favor a high mass ratio, 0.76≲ q≲0.95, and a donor-star mass of approximately 0.67≲ M_2/M_⊙≲0.89. In the limiting case of q=1, the WD mass has an upper limit of 1.14 M_⊙. Together with the X-ray measurements, this indicates a relatively massive WD. The lack of an independent measurement of the WD dynamical mass leaves it unclear whether the dynamical mass is consistent with the X-ray measurements or whether the X-ray mass is underestimated, as has been found for other IPs. Thus, our constraints make IGR J17014-4306 an important system for improving our understanding of IPs.
ER -