Redshift identification of X-ray selected active galactic nuclei in the J1030 field: searching for large-scale structures and high-redshift sources. (arXiv:2109.08162v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Marchesi_S/0/1/0/all/0/1">Stefano Marchesi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mignoli_M/0/1/0/all/0/1">Marco Mignoli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gilli_R/0/1/0/all/0/1">Roberto Gilli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Peca_A/0/1/0/all/0/1">Alessandro Peca</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bolzonella_M/0/1/0/all/0/1">Micol Bolzonella</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nanni_R/0/1/0/all/0/1">Riccardo Nanni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Annunziatella_M/0/1/0/all/0/1">Marianna Annunziatella</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Balmaverde_B/0/1/0/all/0/1">Barbara Balmaverde</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brusa_M/0/1/0/all/0/1">Marcella Brusa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Calura_F/0/1/0/all/0/1">Francesco Calura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cassara_L/0/1/0/all/0/1">Letizia P. Cassarà</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chiaberge_M/0/1/0/all/0/1">Marco Chiaberge</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Comastri_A/0/1/0/all/0/1">Andrea Comastri</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cusano_F/0/1/0/all/0/1">Felice Cusano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+DAmato_Q/0/1/0/all/0/1">Quirino D'Amato</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Iwasawa_K/0/1/0/all/0/1">Kazushi Iwasawa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lanzuisi_G/0/1/0/all/0/1">Giorgio Lanzuisi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marchesini_D/0/1/0/all/0/1">Danilo Marchesini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Morishita_T/0/1/0/all/0/1">Takahiro Morishita</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Prandoni_I/0/1/0/all/0/1">Isabella Prandoni</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rossi_A/0/1/0/all/0/1">Andrea Rossi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tozzi_P/0/1/0/all/0/1">Paolo Tozzi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vignali_C/0/1/0/all/0/1">Cristian Vignali</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vito_F/0/1/0/all/0/1">Fabio Vito</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zamorani_G/0/1/0/all/0/1">Giovanni Zamorani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Norman_C/0/1/0/all/0/1">Colin Norman</a>
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 $zgeq$4, which we plan to either confirm or reject in the
near future with dedicated spectroscopic campaigns.
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 $zgeq$4, which we plan to either confirm or reject in the
near future with dedicated spectroscopic campaigns.
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