NICER observation list: Target ID 770002

Abstract

IXPE has demonstrated that weakly magnetized neutron star low-mass X-ray binaries (NS-LMXBs) tend to be significantly polarized in the X-rays. IXPE is thus shedding new light on the geometry of the accretion flow in these sources. However, these observations also open new questions. Bright atoll sources are particularly puzzling, as the IXPE results range from non-detection in GS 1826-238 to 10% polarization in 4U 1820-303. We propose to observe with IXPE the remaining four X-ray brightest persistent atolls, doubling the current sample size. We request an exposure of 20 to 50 ks per source (150 ks in total), to reach a minimum detectable polarization of 1%. We also ask for joint 10 ks observations with NICER, to provide good spectral coverage.
Obsid RA DEC l b Start End Exposure Number of
Modules
Number of
Processing
Status of
Processing
Date of
Processing
Public
date
7700020101 279.990 5.036 36.118 4.842 60414.7744 60414.9176 3274.0 50 3 VALIDATED 60424.9 60428
7700020102 279.990 5.036 36.119 4.842 60415.0325 60415.4981 4519.0 50 7 VALIDATED 60437.0 60429