1. The NuSTAR Extragalactic Survey: A 1 st Look at the Distant High-Energy X-ray Background D.R. Ballantyne (Georgia Tech) on behalf of M. Ajello, D. Alexander, R. Assef, M. Balokovic, F. Bauer, S. Boggs, K. Boydstun, C. Bridge, F. Christensen, W. Craig, G. Lansbury, A. Del Moro, P. Eisenhardt, A. Gonzalez, C. Hailey, F. Harrison, T.-N. Lu, D. Stern, W. Zhang and the rest of the NuSTAR Extragalactic Surveys Working Group

2. The X-ray Background: Current Status ~100% directly resolved at 50% at 6-10 keV by Chandra & XMM ~1-2% directly resolved at 20-30 keV peak by Swift-BAT/INTEGRAL etc Goals for NuSTAR Composition of ~20-30 keV peak and resolving >30-50% of the X-ray background from direct detections and stacking Chandra/XMM sources Trace the evolution of AGNs and obscuration with redshift (NuSTAR AGN selection almost irrespective of obscuration) Measure to high precision the high- energy properties of local AGNs to better define the physical components and modelling of the XRB DRB, Draper, Madsen, Rigby & Treister (2011) NuSTAR

3. Deep: E-CDF-S (GOODS-S) ~200 ks/pointing over 0.25 deg 2 Medium: COSMOS ~25-50 ks/pointing over 1-2 deg 2 Large area: serendipitous Serendipitous detections, principally 100 Swift-BAT AGNs (~16 ks each) but also other NuSTAR targets to get ~3-4 deg 2 of coverage Extragalactic surveys: three-tiered design See poster 109.09 by F. Civano on 1 st ECDF-S and COSMOS results

4. Multi-wavelength properties of 3C382 serendipitous source Serendipitous Survey NuSTAR A NuSTAR B XMM-Newton Optical3.4um WISE 12um WISE Produced by: G. Lansbury, D. Alexander, A. Del Moro, J. Mullaney NuSTAR 3-24 keV image of 3C382 field 3C382 Serendipitous detection Current statistics: 33 serendipitous sources detected by NuSTAR in 64 fields - 20 have been spectroscopically identified to date (including one known Galactic CV) Here, I report on the properties of the first 10 AGNs discovered in the serendipitous survey (Alexander et al. in prep).

5. First 10 serendips: optical spectra Overall: 5 (~50%) are broad-line AGNs, 4 (~40%) are narrow-line AGNs, and 1 BL Lac Example optical spectra: most of the serendipitous sources were not studied before and so we have been obtaining optical spectroscopic follow up. z=0.020 narrow-line AGN (hosted in a dwarf galaxy) z=2.923 broad-line AGN z=0.891 narrow-line AGN z=1.073 broad-line AGN

6. First 10 serendips: basic properties NuSTAR is ~100x more sensitive than Swift-BAT for AGN in Burlon et al. (2011): average redshift is z~0.8 (z~0.03 for Swift-BAT) average X-ray luminosity is ~3x10 44 erg/s (~3x10 43 erg/s for Swift-BAT) X-ray band ratios suggest that AGNs are Compton thin with N H <5x10 23 cm -2. NLAGN BLAGN NLAGN BLAGN

7. First 10 serendips: X-ray spectral fitting Broad-band 0.5-30 keV spectral fitting (absorbed power law): need to use C statistics for the majority of the sources, which are faint. Results: 5 AGNs (~50%) are obscured with N H ~10 22 -10 24 cm -2 (  ~1.8). Broadly consistent with the Swift-BAT results of Burlon et al. (2011) but AGNs are ~10x more luminous. Lack of Compton-thick AGNs at this early stage is consistent with the Swift-BAT sample and theoretical expectations. Swift-XRT (or Chandra/XMM-Newton) NuSTAR

8. First 10 serendips: joint rest-frame 10-40 keV Joint spectral fitting of the rest-frame 10-40 keV data for all non-beamed sources with L X >10 43 erg/s. The best-fitting spectral slope and constraint on reflection (  ~1.9 and R<1.4) are consistent with local AGNs (see poster 109.02 by Ballantyne). With these results we are starting to constrain models for the evolution in the properties of the obscuring region with redshift.

9. Summary All 3 NuSTAR extragalactic surveys underway Initial results show that, as advertised, NuSTAR will efficiently detect z<~ 2 Compton-thin AGNs regardless of the obscuring column-density NuSTAR (launch in 9 days!!)

10. 10

11. First 10 serendips: UV-mid-infrared SEDs Key result: average stellar mass of z~0.8 NuSTAR AGNs is ~10 11 solar masses, as compared to ~2x10 10 solar masses for z~0.03 Swift-BAT AGNs (Koss et al. 2011) – “downsizing” in the AGN population. Example UV-mid-IR SEDs for two sources. Model fitting performed by Roberto Assef following Assef et al. (2008) and constraints AGN and host galaxy components, including dust reddening (E(B-V)).