eRASSU J043115.8-711730 :the first pulsating symbiotic super-soft X-ray source in the Magellanic Bridge

@misc{saha2026erassu,
  title = {{eRASSU J043115.8-711730 :the first pulsating symbiotic super-soft X-ray source in the Magellanic Bridge}},
  author = {Tathagata Saha and Chandreyee Maitra and Philip Charles and Frank Haberl and David Kaltenbrunner and Andrzej Udalski and David Buckley and Itumeleng Monageng and Lee Townsend and Manami Sasaki and Sara Saeedi and Mara Salvato},
  howpublished = {arXiv},
  year = {2026},
  month = aug,
  doi = {10.48550/arxiv.2607.27730},
  eprint = {2607.27730},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2607.27730},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - eRASSU J043115.8-711730 :the first pulsating symbiotic super-soft X-ray source in the Magellanic Bridge
AU  - Tathagata Saha
AU  - Chandreyee Maitra
AU  - Philip Charles
AU  - Frank Haberl
AU  - David Kaltenbrunner
AU  - Andrzej Udalski
AU  - David Buckley
AU  - Itumeleng Monageng
AU  - Lee Townsend
AU  - Manami Sasaki
AU  - Sara Saeedi
AU  - Mara Salvato
PY  - 2026
DA  - 2026/08/14
PB  - arXiv
DO  - 10.48550/arxiv.2607.27730
UR  - https://arxiv.org/abs/2607.27730
AB  - The Magellanic Bridge stellar population is a relic of the tidal interaction between the Large and Small Magellanic Clouds. A comprehensive view of the evolution of the Bridge stellar population requires probing the compact remnants of stellar evolution, otherwise hidden at optical wavelengths. The all-sky survey conducted by the eROSITA instrument on-board the Spectrum Roentgen Gamma observatory has discovered a significant population of compact-object-powered systems in the Bridge using X-ray. The candidate super-soft source eRASSU J043115.8-711730 (hereafter J0431-71) was discovered as a part of this campaign, and we present here a deeper study of this source using XMM-Newton and SALT spectroscopy, long-term optical-infrared photometry using OGLE, ATLAS, ASAS-SN, WISE, and GAIA data. J0431-71 is a highly variable super-soft X-ray source, classified as a red giant with the GAIA color-magnitude diagram. The source exhibits: (a) a thermal X-ray spectrum with a temperature of kT∼30 eV and a bright state luminosity of 3.2×10^37~erg~s^−1 in the 0.15-1 keV band, (b) Balmer emission lines, [Fe X] coronal line, HeII emission, and the Bowen fluorescence blend, (c) an optical and infrared periodicity of ∼500-560 days in phase with the X-ray-UV emission, (d) a 'redder-when-brighter' trend in the stellar emission with a ∼520 day period indicating a pulsating donor star. We argue that the observed spectral and temporal properties in J0431-71 are consistent with a high-accretion rate onto a white-dwarf via Roche-lobe overflow, making J0431-71 the first symbiotic source discovered in the Bridge.
ER  -