James Webb Space Telescope Feed Post

PEARLS: NuSTAR and XMM-Newton Extragalactic Survey of the JWST North Ecliptic Pole Time-Domain Field II

Illustrations of secure (top), ambiguous (middle), and unidentified (bottom) associations of XMM-Newton sources. Negative images left to right are HSC i, MMIRS J, and HST+JWST (11-filter mosaic: HST F275W, F435W, and F606W; JWST F090W, F115W, F150W, F200W, F277W, F356W, F410M, and F444W). All images are oriented north up, east left and centered at the centroid of the XMM-Newton detections. The image scale is indicated in the top row. Solid circles show the XMM-Newton position uncertainty, and dashed circles show the 5" matching radius. Labels show i-band magnitudes measured from HSC (cyan square), J-PAS (green circle), or SDSS (red cross) or IR magnitudes measured by MMIRS (J-band, red square) or WISE (W1, green circle). Only ancillary counterparts within the matching radius and with LR>LRth are plotted. The ancillary counterparts with the highest LR are plotted as filled symbols. XMM 17 is the bright Seyfert galaxy discussed by Willner et al. (2023, their Figure 3). XMM 86 was not covered by JWST. Abstract: We present the second NuSTAR and XMM-Newton extragalactic survey of the JWST North Ecliptic Pole (NEP) Time-Domain Field (TDF). The first NuSTAR NEP-TDF survey (Zhao et al. 2021) had 681 ks total exposure time executed in NuSTAR cycle 5, in 2019 and 2020. This second survey, acquired from 2020 to 2022 in cycle 6, adds 880 ks of NuSTAR exposure time. The overall NuSTAR NEP-TDF survey is the most sensitive NuSTAR extragalactic survey to date, and a total of 60 sources were detected above the 95% reliability threshold. We constrain the hard X-ray number counts, logN-log S, down to 1.7 x 10-14 erg cm-2 s-1 at 8-24 keV and detect an excess of hard X-ray sources at the faint end. About 47% of the NuSTAR-detected sources are heavily obscured (NH > 1023 cm-2), and 18+20% of the NuSTAR-detected sources are Compton-thick (N>1024 cm-2). These fractions are consistent with those measured in other NuSTAR surveys. Four sources presented >2s variability in the 3-year survey. In addition to NuSTAR, a total of 62 ks of XMM-Newton observations were taken during NuSTAR cycle 6. The XMM-Newton observations provide soft X-ray (0.5-10keV) coverage in the same field and enable more robust identification of the visible and infrared counterparts of the NuSTAR-detected sources. A total of 286 soft X-ray sources were detected, out of which 214 XMM-Newton sources have secure counterparts from multiwavelength catalogs.