Chandra position of the new Galactic center transient MAXI J1744-294
ATel #17087; S. Mandel, B. Levin, K. Mori, C. Hailey (Columbia U.), M. Bachetti (INAF), N. Degenaar (U. Amsterdam), P. Draghis (MIT), J. Grindlay, J. Hong (Harvard CfA), M. Nynka (MIT), M. Parra (Ehime U.), G. Ponti (INAF, MPE), M. Reynolds (U. Michigan), M. Shidatsu (Ehime U.), J. Tomsick (UCB), R. Wijnands (U. Amsterdam)
on 19 Mar 2025; 14:05 UT
Credential Certification: Shifra Mandel (ss5018@columbia.edu)
Subjects: X-ray, Black Hole, Transient
MAXI J1744-294 is a bright new transient in the Galactic center, first detected by MAXI/GSC on Jan. 2, 2025 (ATels #16975, #16983). More observations soon followed, by NinjaSat (ATel #17009), Swift/BAT and Swift/XRT (ATel #17010), NuSTAR (ATel #17031), NICER (ATel #17040), MeerKAT (ATel #17045), XRISM (ATel#17063), and Einstein Probe (ATel #17068). Here we report a follow-up observation with the Chandra X-ray Observatory.
A Chandra/ACIS-S ToO observation was performed on March 9, 2025 with an exposure of 9.3 ks. Due to the brightness of the transient, ACIS-S was operated in 1/8th subarray mode (S2+S3) with the High-Energy Transmission Grating (HETG), with a frame time of 0.4s. MAXI J1744-294 was detected as a very bright, heavily piled up source near the center of the image, with two distinct dispersion streaks (HEG and MEG) intersecting at the 0th order position. We used the tg_findzo CIAO algorithm to find the 0th order source position: (RA, Dec) = (17:45:40.476, -29:00:46.10). The celldetect tool confirmed this position and generated an uncertainty of 1.2″ (68% C.L.). This position is consistent with the location published by the MeerKAT team (ATel #17045), and further confirms that MAXI J1744-294 is indeed a new transient that has not previously been observed in outburst. The Chandra position is located at a projected offset of < 20″ from Sgr A*.
The Chandra catalog (CSC v2.1) source 2CXO J174540.4-290046 is located within 1″ of MAXI J1744-294's position centroid, but it is unclear whether this source is the quiescent counterpart to MAXI J1744-294.
Analysis of the HEG and MEG dispersion spectra will be presented in our forthcoming paper along with contemporaneous NuSTAR observation data.
We thank the Chandra team for their assistance in planning this observation.
