eRASSU J043115.8-711730: the first pulsating symbiotic supersoft X-ray source in the Magellanic Bridge
Saha T, Maitra C, Charles P, Haberl F, Kaltenbrunner D, Udalski A, Buckley D, Monageng I, Townsend L, Sasaki M, Saeedi S, Salvato M (2026)
Publication Type: Journal article
Publication year: 2026
Journal
Book Volume: 551
Article Number: stag1474
Journal Issue: 4
Abstract
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 onboard the Spectrum Roentgen Gamma observatory has discovered a significant population of compact-object-powered systems in the Bridge using X-ray. The candidate supersoft 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 supersoft X-ray source, classified as a red giant with the GAIA colour–magnitude diagram. The source exhibits: (a) a thermal X-ray spectrum with a temperature of (Formula presented) (Formula presented) 30 eV and a bright state luminosity of 3.2(Formula presented) erg s(Formula presented) in the 0.15-1 keV band, (b) Balmer emission lines, [Fe x] coronal line, He ii emission, and the Bowen fluorescence blend, (c) an optical and infrared periodicity of (Formula presented) 500–560 d in phase with the X-ray–UV emission, and (d) a ‘redder-when-brighter’ trend in the stellar emission with a (Formula presented) 520 d 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 on to a white dwarf via Roche lobe overflow, making J0431–71 the first symbiotic source discovered in the Bridge.
Authors with CRIS profile
Manami Sasaki
Professur für Multiwellenlängenastronomie
Sara Saeedi
Professur für Multiwellenlängenastronomie
Involved external institutions
University of Warsaw / Uniwersytet Warszawski
Poland (PL)
South African Astronomical Observatory (SAAO)
South Africa (ZA)
Max-Planck-Institut für extraterrestrische Physik (MPE) / Max Planck Institute for Extraterrestrial Physics
Germany (DE)
Inter-University Centre for Astronomy and Astrophysics (IUCAA)
India (IN)
University of Southampton
United Kingdom (GB)
Poland (PL)
South African Astronomical Observatory (SAAO)
South Africa (ZA)
Max-Planck-Institut für extraterrestrische Physik (MPE) / Max Planck Institute for Extraterrestrial Physics
Germany (DE)
Inter-University Centre for Astronomy and Astrophysics (IUCAA)
India (IN)
University of Southampton
United Kingdom (GB)
How to cite
APA:
Saha, T., Maitra, C., Charles, P., Haberl, F., Kaltenbrunner, D., Udalski, A.,... Salvato, M. (2026). eRASSU J043115.8-711730: the first pulsating symbiotic supersoft X-ray source in the Magellanic Bridge. Monthly Notices of the Royal Astronomical Society, 551(4). https://doi.org/10.1093/mnras/stag1474
MLA:
Saha, Tathagata, et al. "eRASSU J043115.8-711730: the first pulsating symbiotic supersoft X-ray source in the Magellanic Bridge." Monthly Notices of the Royal Astronomical Society 551.4 (2026).
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