NICER observation list: Target ID 255005


Very-faint X-ray transients undergo outbursts of accretion with a peak X-ray luminosity much lower than that of other black hole and neutron star low-mass X-ray binaries. Studying these objects is of great interest because they trace a poorly understood accretion regime and may represent neutron stars with relatively strong magnetic fields or a missing population of short-period binaries. To study the outburst of a known very-faint X-ray transient in detail, we propose 40 ks of NICER ToO monitoring observations, divided into 20 observations of 2 ks spanning two months. These observations will allow us to i) perform the first dedicated, multi-epoch timing study of a VFXT outburst and ii) monitor the spectral and flux evolution of the target.
Obsid RA DEC l b Start End Exposure Number of
Number of
Status of
Date of
2550050101 262.166 -29.364 357.652 2.894 58624.9679 58624.9792 868.0 52 3 VALIDATED 58631.7 58638
2550050102 262.165 -29.363 357.652 2.896 58625.0323 58625.1731 2152.0 52 2 VALIDATED 58631.8 58639