Last year Swift monitoring of XMMU J174445.5-295044 during quiescence
ATel #15237; F. Pellegatta (INAF-OA Brera, Universita` degli studi di Milano), S. Campana (INAF-OA Brera)
on 23 Feb 2022; 16:10 UT
Credential Certification: Sergio Campana (sergio.campana@brera.inaf.it)
Subjects: X-ray, Binary, Neutron Star, Transient
We monitored XMMU J174445.5-295044 bi-weekly during the observation of the Galactic center region with Swift (CBS monitoring campaign; Campana 2021, Atel #14438). The transient lies at the edge of one of our pre-selected pointings (ID 13799). XMMU J174445.5-295044 fell 8/13 within the Swift/XRT field of view.
When within the field of view, XMMU J174445.5-295044 was first detected at a stable quiescent level of ~(4.1E+/-1.0)E-02 c/s from 2021-06-14 to 2021-09-02. This rate increased linearly to reach (16.9+/-2.3)E-02 c/s on 2021-10-28 (501 s exposure) at the end of the campaign, terminated due to the Sun constraints.
The overall spectrum (2.9ks), extracted thanks to the Leicester University tools (Evans et al. 2009), provides us with a heavily absorbed [N_H=1.7(+0.9,-0.7)Ã10^23 cm^-2], hard [Power law Gamma=1.5(+1.2,-1.0), 90% confidence level errors] spectrum.
The 2-10 keV unabsorbed flux during the last observation is 8.9E-11 erg/cm2/s (7E35 erg/s at 8 kpc).
To compare our results with the recent INTEGRAL JEM-X detection (Chenevez et al. 2021, Atel #15236), we computed the absorbed 3-10 keV flux and evaluate a spectral factor correction for the harder spectrum, deriving that our latest detection is ~30 times dimmer than the first INTEGRAL JEM-X detection.
