The NuSTAR Extragalactic Surveys: Overview and Catalog from the COSMOS Field
| Autor: | Civano, F., Hickox, R. C., Puccetti, S., Comastri, A., Mullaney, J. R., Zappacosta, L., LaMassa, S. M., Aird, J., Alexander, D. M., Ballantyne, D. R., Bauer, F. E., Brandt, W. N., Boggs, S. E., Christensen, F. E., Craig, W. W., Del-Moro, A., Elvis, M., Forster, K., Gandhi, P., Grefenstette, B. W., Hailey, C. J., Harrison, F. A., Lansbury, G. B., Luo, B., Madsen, K., Saez, C., Stern, D., Treister, E., Urry, M. C., Wik, D. R., Zhang, W. |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | ApJ, 808, 185 (2015) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1088/0004-637X/808/2/185 |
| Popis: | To provide the census of the sources contributing to the X-ray background peak above 10 keV, 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 deg2 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 x 10^-14 erg/cm2/s in the 3-24 keV, 3-8 keV and 8-24 keV bands, respectively. By combining detections in 3 bands, we have a sample of 91 NuSTAR sources with 10^42 -10^45.5 erg/s 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 four 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 AGN 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 10^24 /cm2, implying the source is Compton-thick. This source was not previously recognized as such without the >10 keV data. Comment: 20 pages, published in the Astrophysical Journal |
| Databáze: | arXiv |
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