Determination of MAXI J1744-294 as a repeat outburst of the 2016 transient Swift J174540.2-290037

ATel #17663; S. Mandel, K. Mori (Columbia U.), Z. Hua (Nanjing U.), M. Reynolds (OSU), N. Degenaar (U. Amsterdam), L. Marra (INAF-IAPS), M. Parra (Ehime U.), P. Draghis (MIT)
on 10 Feb 2026; 09:29 UT
Credential Certification: Shifra Mandel (ss5018@columbia.edu)

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MAXI J1744-294 was first detected as a bright Galactic center transient by MAXI/GSC on Jan. 2, 2025 (ATels #16975, #16983). Later observations by Swift/XRT (ATel #17010) deemed it a new source, as its Swift/XRT position was removed from that of any previously identified transients. However, follow-up observations with Chandra (ATel #17087) showed a more accurate position offset by ≈22″ from the Swift/XRT position. The Chandra position is consistent with the location published by the MeerKAT team (ATel #17045).

We revisit the designation of MAXI J1744-294 as a new transient, using the updated Chandra position. While this location does not overlap any X-ray transients in the SIMBAD database, we note that Swift J174540.2-290037, a transient that outburst in 2016, has a refined Chandra position (Mori et al, 2019) that is coincident with that of MAXI J1744-294. Like MAXI J1744-294, the Swift/XRT coordinates for Swift J174540.2-290037, which are listed in SIMBAD, are offset from the Chandra position, in this case by ≈10″. Therefore, when considering the Swift/XRT positions of the two sources — or indeed the Swift/XRT position of any one of the sources and the Chandra coordinates of the other — they will not overlap. However, the two Chandra positions do overlap. We therefore determine that MAXI J1744-294 is most likely a repeat outburst of the 2016 transient Swift J174540.2-290037.

A detailed analysis of the 2025 MAXI J1744-294/Swift J174540.2-290037 outburst can be found in Mandel et al. (2025), where it is identified as a black hole candidate (consistent with the findings for Swift J174540.2-290037 by Mori et al, 2019). A spectro-polarimetric study of the source, based on IXPE data, was published by Marra et al. (2025). Additional studies using XRISM data (Parra et al., 2026) are currently in prep and expected to be released in the coming weeks.

ATel #17659 indicates that MAXI J1744-294 is still in outburst; additional observations are expected to follow.

A multiwavelength study of the Galactic center black hole candidate MAXI J1744-294