NICER observation list: Target ID 770003

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
7700030101 264.743 -44.451 346.054 -6.994 60550.0670 60550.6023 1813.0 52 3 VALIDATED 60561.4 60564
7700030102 264.743 -44.450 346.054 -6.994 60551.5522 60551.8264 0.0 41 4 VALIDATED 60563.2 60565
7700030103 264.743 -44.451 346.054 -6.994 60552.0800 60552.1484 386.0 50 3 VALIDATED 60563.3 60566