SVOM/MXT observations of EP J223759.5+531421

ATel #17876; Diego Gotz (CEA Saclay), Lin Lin (BNU), Lian Tao (IHEP), Alexis Coleiro (APC Paris), Edoardo Arrigoni (INAF), Zexi Li (IHEP) Liang Zhang (IHEP)
on 6 Jul 2026; 09:17 UT
Credential Certification: Diego Gotz (diego.gotz@cea.fr)

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SVOM/MXT observed the magnetar candidate EP J223759.5+531421 (EP260628c, ATel #17858, #17870, #17872, #17875) on July 5th from 15:25 UT to 17:31 UT for an effective exposure time of 3.5 ks. The source is detected with an absorbed 0.3-10 keV flux of about 1e-10 erg/cmsq/s, and is well fitted either by a single power law with photon index 1.9+/-0.3 or by the sum of two black bodies of temperatures ~0.4 keV and ~1.4 keV. In the 0.5-2.5 keV energy band a spin period consistent with the one measured by FXT (ATel #17870) is measured at ~4 sigma level. Continued observations by SVOM will be planned in the next days. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. ECLAIRs was developed jointly by APC, CEA, CNES and IRAP.