English

Detection and Evolution of Linear Polarization of the Galactic Center Transient MAXI J1744-294

High Energy Astrophysical Phenomena 2026-04-10 v1 Astrophysics of Galaxies

Abstract

MAXI J1744-294, likely a low-mass X-ray binary system, is a Galactic-center transient source, detected at radio and X-ray wavelengths, located approximately 1919'' southeast of Sgr A*. We report the first detection of its variable linear polarization in four epochs spanning 2025 Apr 04--09. The normalized 33 and 43 GHz Stokes parameters qq and uu over the four epochs imply a common Faraday rotation screen with a rotation measure RM =63606861+844=-63\,606^{+844}_{-861} radians m2^{-2}, the third largest RM detected within the Galaxy. The RM is consistent with that of the Galactic center magnetar PSR J1745-2900, giving the first direct evidence that MAXI J1744 lies within the Galactic center region, is bound to Sgr A*, and therefore, is part of the nuclear star cluster. The uniformity in the Galactic center Faraday screen suggests that Sgr A*'s 105\approx-10^5 rad m2^{-2} RM is intrinsic rather than originating from an unrelated line-of-sight source. On 2025 Apr 06, we detected a secondary polarized component with an additional RM 6000\approx-6000 rad m2^{-2}, which was not seen at any other epoch. Assuming this secondary component primarily cools by synchrotron radiation, the implied local magnetic field strength is \sim15--30 gauss. In the context of a jetted X-ray binary progenitor, the additional RM screen and magnetic field strength are explainable with a short-lived knot in a putative jet.

Keywords

Cite

@article{arxiv.2604.07431,
  title  = {Detection and Evolution of Linear Polarization of the Galactic Center Transient MAXI J1744-294},
  author = {Joseph M. Michail and Sebastiano D. von Fellenberg and Mayura Balakrishnan and Geoffrey C. Bower and Nicole M. Ford and Zach Sumners and Giovanni G. Fazio and Daryl Haggard and Joseph L. Hora and Garrett K. Keating and J. D. Livingston and Sera Markoff and Bart Ripperda and Sophia Sánchez-Maes and Howard A. Smith and S. P. Willner and Jun-Hui Zhao},
  journal= {arXiv preprint arXiv:2604.07431},
  year   = {2026}
}

Comments

15 pages, 6 figures, 4 tables, accepted to ApJ