The NuSTAR extragalactic surveys: Overview and catalog from the cosmos field

Journal Article · Sat Aug 01 04:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/808/2/185· OSTI ID:22882852

Civano, F.; LaMassa, S. M. ^[1]; Hickox, R. C. ^[2]; Puccetti, S. ^[3]; Comastri, A. ^[4]; Mullaney, J. R. ^[5]; Zappacosta, L. ^[6]; Aird, J.; Alexander, D. M.; Del-Moro, A.; Gandhi, P. ^[7]; Ballantyne, D. R. ^[8]; Bauer, F. E. ^[9]; Brandt, W. N. ^[10]; Boggs, S. E.; Craig, W. W. ^[11]; Christensen, F. E. ^[12]; Elvis, M. ^[13]; Forster, K.; Grefenstette, B. W. ^[14] ; others, and

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1. Yale Center for Astronomy and Astrophysics, 260 Whitney Avenue, New Haven, CT 06520 (United States)
2. Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States)
3. ASDC—ASI, Via del Politecnico, I-00133 Roma (Italy)
4. INAF—Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy)
5. The Department of Physics and Astronomy, The University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom)
6. INAF—Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monte Porzio Catone (RM) (Italy)
7. Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)
8. Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States)
9. Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, 306, Santiago 22 (Chile)
10. Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)
11. Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)
12. DTU Space—National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark)
13. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
14. Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1216 E. California Blvd, Pasadena, CA 91125 (United States)

To provide the census of the sources contributing to the X-ray background peak above 10 keV, Nuclear Spectroscopic Telescope Array (NuSTAR) is performing extragalactic surveys using a three-tier “wedding cake” approach. We present the NuSTAR survey of the COSMOS field, the medium sensitivity, and medium area tier, covering 1.7 deg{sup 2} and overlapping with both Chandra and XMM-Newton data. This survey consists of 121 observations for a total exposure of ∼3 Ms. To fully exploit these data, we developed a new detection strategy, carefully tested through extensive simulations. The survey sensitivity at 20% completeness is 5.9, 2.9, and 6.4 × 10{sup −14} erg cm{sup −2} s{sup −1} in the 3–24, 3–8, and 8–24 keV bands, respectively. By combining detections in 3 bands, we have a sample of 91 NuSTAR sources with 10{sup 42}–10{sup 45.5} erg s{sup −1} luminosities and redshift z = 0.04–2.5. Thirty-two sources are detected in the 8–24 keV band with fluxes ∼100 times fainter than sources detected by Swift-BAT. Of the 91 detections, all but 4 are associated with a Chandra and/or XMM-Newton point-like counterpart. One source is associated with an extended lower energy X-ray source. We present the X-ray (hardness ratio and luminosity) and optical-to-X-ray properties. The observed fraction of candidate Compton-thick active galactic nuclei measured from the hardness ratio is between 13%–20%. We discuss the spectral properties of NuSTAR J100259+0220.6 (ID 330) at z = 0.044, with the highest hardness ratio in the entire sample. The measured column density exceeds 10{sup 24} cm{sup −2}, implying the source is Compton-thick. This source was not previously recognized as such without the >10 keV data.

• OSTI ID: 22882852
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 808; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COMPUTERIZED SIMULATION
COSMIC X-RAY SOURCES
GALAXY NUCLEI
HARDNESS
LUMINOSITY
RED SHIFT
SENSITIVITY
TELESCOPES
UNIVERSE