Redshift identification of X-ray selected active galactic nuclei in the J1030 field: searching for large-scale structures and high-redshift sources
| Autor: | Marchesi, Stefano, Mignoli, Marco, Gilli, Roberto, Peca, Alessandro, Bolzonella, Micol, Nanni, Riccardo, Annunziatella, Marianna, Balmaverde, Barbara, Brusa, Marcella, Calura, Francesco, Cassarà, Letizia P., Chiaberge, Marco, Comastri, Andrea, Cusano, Felice, D'Amato, Quirino, Iwasawa, Kazushi, Lanzuisi, Giorgio, Marchesini, Danilo, Morishita, Takahiro, Prandoni, Isabella, Rossi, Andrea, Tozzi, Paolo, Vignali, Cristian, Vito, Fabio, Zamorani, Giovanni, Norman, Colin |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | A&A 656, A117 (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361/202141416 |
| Popis: | We publicly release the spectroscopic and photometric redshift catalog of the sources detected with Chandra in the field of the $z$=6.3 quasar SDSS J1030+0525. This is currently the fifth deepest X-ray field, and reaches a 0.5-2 keV flux limit $f_{\rm 0.5-2}$=6$\times$10$^{-17}$ erg s$^{-1}$ cm$^{-2}$. By using two independent methods, we measure a photometric redshift for 243 objects, while 123 (51%) sources also have a spectroscopic redshift, 110 of which coming from an INAF-Large Binocular Telescope (LBT) Strategic Program. We use the spectroscopic redshifts to determine the quality of the photometric ones, and find it in agreement with that of other X-ray surveys which used a similar number of photometric data-points. In particular, we measure a sample normalized median absolute deviation $\sigma_{NMAD}$=1.48||$z_{phot}$-$z_{spec}$||/(1+$z_{spec}$)=0.065. We use these new spectroscopic and photometric redshifts to study the properties of the Chandra J1030 field. We observe several peaks in our spectroscopic redshift distribution between $z$=0.15 and $z$=1.5, and find that the sources in each peak are often distributed across the whole Chandra field of view. This evidence confirms that X-ray selected AGN can efficiently track large-scale structures over physical scales of several Mpc. Finally, we computed the Chandra J1030 $z>$3 number counts: while the spectroscopic completeness at high-redshift of our sample is limited, our results point towards a potential source excess at $z\geq$4, which we plan to either confirm or reject in the near future with dedicated spectroscopic campaigns. Comment: 21 pages, 15 figures. Accepted for publication in Astronomy and Astrophysics |
| Databáze: | arXiv |
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