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Durham University

Department of Physics

Staff profile

Publication details for Prof David Alexander

Mullaney, J.R., Del-Moro, A., Aird, J., Alexander, D.M., Civano, F.M., Hickox, R.C., Lansbury, G.B., Ajello, M., Assef, R., Ballantyne, D.R., Balok\acute, M., Bauer, F.E., Brandt, W.N., Boggs, S.E., Brightman, M., Christensen, F.E., Comastri, A., Craig, W.W., Elvis, M., Forster, K., Gandhi, P., Grefenstette, B.W., Hailey, C.J., Harrison, F.A., Koss, M., LaMassa, S.M., Luo, B., Madsen, K.K., Puccetti, S., Saez, C., Stern, D., Treister, E., Urry, C.M., Wik, D.R., Zappacosta, L. & Zhang, W. (2015). The NuSTAR Extragalactic Surveys: Initial Results and Catalog from the Extended Chandra Deep Field South. Astrophysical Journal 808(2): 184.

Author(s) from Durham


We present the initial results and the source catalog from the Nuclear Spectroscopic Telescope Array
(NuSTAR) survey of the Extended Chandra Deep Field South (hereafter, ECDFS)—currently the deepest
contiguous component of the NuSTAR extragalactic survey program. The survey covers the full ≈30′ × 30′ area of
this field to a maximum depth of ≈360 ks (»220 ks when corrected for vignetting at 3–24 keV), reaching
sensitivity limits of » ´ 1.3 10 erg s cm - -- 14 1 2 (3–8 keV), » ´ 3.4 10 erg s cm - -- 14 1 2 (8–24 keV), and
» ´ 3.0 10 erg s cm - -- 14 1 2 (3–24 keV). A total of 54 sources are detected over the full field, although five of
these are found to lie below our significance threshold once contaminating flux from neighboring (i.e., blended)
sources is taken into account. Of the remaining 49 that are significant, 19 are detected in the 8–24 keV band. The
8–24 to 3–8 keV band ratios of the 12 sources that are detected in both bands span the range 0.39–1.7,
corresponding to a photon index range of G » - 0.5 2.3, with a median photon index of G =  1.70 0.52. The
redshifts of the 49 sources in our main sample span the range z = - 0.21 2.7, and their rest-frame 10–40 keV
luminosities (derived from the observed 8–24 keV fluxes) span the range L10 40 keV (0.7 300) 10 erg s »- ´ 43 1 - - ,
sampling below the “knee” of the X-ray luminosity function out to z ~ - 0.8 1. Finally, we identify one
NuSTAR source that has neither a Chandra nor an XMM-Newton counterpart, but that shows evidence of nuclear
activity at infrared wavelengths and thus may represent a genuine, new X-ray source detected by NuSTAR in the