SIMBAD references

The James Webb Space Telescope North Ecliptic Pole (NEP) Time-Domain Field (TDF) has been monitored by Nuclear Spectroscopic Telescope Array (NuSTAR) and XMM-Newton with a regular cadence for 5 yr, starting in 2019. The survey has accumulated 3.5 Ms of NuSTAR exposure and 228 ks quasi-simultaneous XMM-Newton observations covering 0.31 deg². This paper presents the results from the most recent 2 years' worth of 2 Ms NuSTAR and 166 ks XMM observations in NuSTAR cycles 8 and 9. These observations reached a 20% area flux of 2.20 × 10^–14 erg cm^–2 s^–1 in the 8-24 keV band. Note that 75 NuSTAR sources and 274 XMM-Newton sources are detected at 99% reliability level. The logN-logS measured in cycles 8+9 are consistent with those measured in the previous cycle 5+6 NuSTAR NEP survey, but in a larger area (0.3 deg² compared with 0.19 deg²). The slope of the cycles 8+9 8-24 keV logN-logS curve is flatter than other works (α₈₉ = 1.13 ± 0.46), but is consistent with the Euclidean value of α = 1.50. In addition, we found ∼36% of the NuSTAR sources to be heavily obscured (N_H ≥ 10²³ cm^–2). The Compton-thick (N_H ≥ 10²⁴ cm^–2) active galactic nuclei fraction is ${9}_{-8}^{+18} \% $ in the NEP-TDF, which is consistent with the measurements in previous surveys.