Testing X-ray Reprocessing and Mapping the Soft Excess of NGC 7469 with NICER
Testing X-ray Reprocessing and Mapping the Soft Excess of NGC 7469 with NICER
Ethan R. Partington, Edward M. Cackett, Rick Edelson, Keith Horne, Jake A. Miller, Aaron J. Barth, Jonathan Gelbord, Juan V. Hernández Santisteban
AbstractWe present an X-ray/UV reverberation analysis of NGC 7469 across 210 days, using daily NICER observations with contemporaneous monitoring by Swift UVOT+XRT. We model the X-ray spectrum with a power law continuum and a soft excess during each NICER epoch. These emission sources demonstrate correlated flux variability with a lag consistent with zero days. We find that the power law emission is consistent with a compact X-ray corona, and that the soft excess can be explainedby reflected coronal emission from the inner accretion disk. We test the relationship between changes in the flux of the X-ray corona and the UVW2 continuum, finding strong correlation and a negative X-ray lag of less than one day. This is consistent with a scenario in which the X-ray corona drives the UVW2 light curve through thermal reprocessing