We present the first IXPE spectro-polarimetric observation of the black hole candidate MAXI J1744−294, a transient X-ray source discovered during a bright 2025 outburst in the Galactic center region. During the ∼150 ks observation, the source was found in the soft state, and its spectrum was well described by an absorbed multicolor disk with a minor high-energy tail. No significant polarization was detected, and we derived a 3σ upper limit on the polarization degree of 1.3% in the 2--8 keV energy band. This result is consistent with previous findings for soft-state black hole binaries observed at low to intermediate inclination angles. By comparing the polarization degree upper limit with theoretical predictions for standard accretion disk emission, we constrain the disk inclination to i≲38∘--71∘, depending on the black hole spin and the disk atmosphere albedo.
@article{arxiv.2506.17050,
title = {Exploring MAXI J1744-294: IXPE insights into a Newly Discovered X-ray Transient},
author = {Lorenzo Marra and Romana Mikušincová and Federico M. Vincentelli and Fiamma Capitanio and Melania Del Santo and Sergio Fabiani and Shifra Mandel and Fabio Muleri and Maxime Parra and Paolo Soffitta and Antonella Tarana and M. Cristina Baglio and Stefano Bianchi and Enrico Costa and Antonino D'Aì and Barbara De Marco and Michal Dovčiak and Vittoria Elvezia Gianolli and Andrea Gnarini and Maitrayee Gupta and Adam Ingram and Guglielmo Mastroserio and Giorgio Matt and Kaya Mori and Pierre-Olivier Petrucci and Jakub Podgorný and Juri Poutanen and James F. Steiner and Jiří Svoboda and Roberto Taverna and Francesco Tombesi and Swati Ravi and Jérôme Rodriguez and Thomas D. Russell and Alexandra Veledina and Shuo Zhang},
journal= {arXiv preprint arXiv:2506.17050},
year = {2025}
}