Contemporaneous AGN flux during NICER observations

Determine the flux state of RX J0437.4−4711 contemporaneous with each NICER observation of PSR J0437−4715 to accurately quantify the AGN’s contribution to the field-of-view background and reduce uncertainty in the pulsar’s spectral-timing analysis.

Background

A nearby Seyfert II AGN (RX J0437.4−4711) contributes non-negligibly to the NICER field-of-view background for PSR J0437−4715. Estimates based on XMM-Newton and NICER observations indicate variability, making static background corrections only approximate.

Accurate modeling of the pulsar’s X-ray signal requires knowledge of the AGN’s flux state at the time of the pulsar observations; the authors explicitly note this information is currently unknown.