Table 2: Photometric redshifts for Optically Faint Sources in CDF-S/GOODS.
XID^a R mag $z_{\rm spec}$ $z_{\rm phot}$ 1 $\sigma$ ^b template^c odds^d X/O^e $N_{\rm H}$ ^f $L_{\rm X}$ ^g Class X^h

(Vega) ([0.5-10] keV)

510 25.4 ... 2.51 2.34-2.59 2.33 0.93 5.1 $\rm 23.44^{23.62}_{23.24}$ 43.79 AGN abs

513 26.1 ... 3.56 3.41-3.68 1.00 0.96 7.6 $\rm 24.16^{24.31}_{24.06}$ 44.19 QSO abs

515 99.0 ... 2.26 2.13-2.46 1.67 0.84 19.7 $\rm 23.50^{23.67}_{23.32}$ 43.75 AGN abs

515 $^{\ast}$ 99.0 ... 2.30 2.24-2.38 2.00 1.00 19.7 $\rm 23.50^{23.67}_{23.32}$ 43.75 AGN abs

518 99.0 ... 0.84 0.58-1.37 2.00 0.33 9.5 $\rm 21.91^{22.31}_{20.68}$ 42.23 AGN unabs

523 99.0 ... 1.32 0.87-6.22 2.00 0.10 11.3 $\rm 22.98^{23.11}_{22.86}$ 43.08 AGN abs

524 99.0 ... 2.36 2.17-2.58 1.67 0.75 18.5 $\rm 23.39^{23.51}_{23.23}$ 43.84 AGN abs

537 99.0 ... 1.54 1.31-1.63 6.00 0.65 9.0 $\rm 22.62^{22.96}_{22.21}$ 42.89 AGN abs

555 25.4 ... 2.28 2.11-2.46 3.00 0.79 0.3 <22.68 42.83 AGN unabs

557 25.4 ... 1.81 1.75-1.96 1.33 0.92 0.3 $\rm 22.66^{23.00}_{22.39}$ 42.88 AGN abs

561 99.0 ... 0.62 0.50-0.87 2.33 0.47 1.6 <21.38 41.82 galaxy

564 99.0 ... 0.43 0.23-0.54 4.33 0.51 1.4 $\rm 21.79^{22.13}_{21.10}$ 41.53 galaxy

572 27.0 ... 2.73 2.21-2.68 2.00 0.53 1.8 $\rm 23.43^{23.68}_{23.17}$ 43.62 AGN abs

583 99.0 ... 2.77 2.66-2.88 1.00 1.00 2.2 $\rm 23.32^{23.49}_{23.11}$ 43.77 AGN abs

589 99.0 ... 1.33 0.89-6.51 2.00 0.10 1.2 $\rm 22.90^{23.11}_{22.57}$ 42.81 AGN abs

593 25.9 ... 2.07 1.83-2.15 2.67 0.77 0.6 $\rm 23.32^{23.61}_{22.95}$ 43.31 AGN abs

599 25.2 ... 2.84 2.48-2.82 1.33 0.76 1.9 $\rm 24.05^{24.17}_{23.92}$ 43.99 AGN abs

605 99.0 ... 4.71 4.39-4.83 5.00 0.85 8.2 $\rm 24.70^{24.93}_{24.49}$ 44.52 QSO abs

$\rm 605A^{\ast}$ 99.0 ... 4.29 4.21-4.32 3.67 0.99 8.2 $\rm 24.70^{24.93}_{24.49}$ 44.52 QSO abs

606 25.3 1.037 1.00 0.92-1.06 2.67 0.95 4.8 $\rm 23.27^{23.40}_{23.14}$ 43.16 AGN abs

610 99.0 ... 2.04 1.94-2.17 1.00 0.90 8.7 >24.18 43.87 AGN abs

614 99.0 ... 1.13 0.60-1.57 4.33 0.27 19.8 $\rm 21.30^{21.93}_{20.62}$ 42.67 AGN unabs

618 25.6 ... 4.66 4.59-4.72 6.00 1.00 0.8 $\rm 23.86^{24.10}_{23.75}$ 44.30 QSO abs

626 25.4 ... 0.59 0.55-0.62 6.00 1.00 0.4 $\rm 22.45^{22.89}_{21.25}$ 42.94 AGN abs

628 99.0 ... 2.07 2.01-2.17 2.00 0.99 1.2 $\rm 23.93^{23.95}_{23.93}$ 43.68 AGN abs

629 25.3 ... 0.56 0.49-0.61 6.00 0.97 0.3 <22.37 41.39 galaxy

**Table 2:** Photometric redshifts for Optically Faint Sources in CDF-S/GOODS.
XID^a	R mag	$z_{\rm spec}$	$z_{\rm phot}$	1 $\sigma$ ^b	template^c	odds^d	X/O^e	$N_{\rm H}$ ^f	$L_{\rm X}$ ^g	Class X^h
	(Vega)								([0.5-10] keV)
510	25.4	...	2.51	2.34-2.59	2.33	0.93	5.1	$\rm 23.44^{23.62}_{23.24}$	43.79	AGN abs
513	26.1	...	3.56	3.41-3.68	1.00	0.96	7.6	$\rm 24.16^{24.31}_{24.06}$	44.19	QSO abs
515	99.0	...	2.26	2.13-2.46	1.67	0.84	19.7	$\rm 23.50^{23.67}_{23.32}$	43.75	AGN abs
515 $^{\ast}$	99.0	...	2.30	2.24-2.38	2.00	1.00	19.7	$\rm 23.50^{23.67}_{23.32}$	43.75	AGN abs
518	99.0	...	0.84	0.58-1.37	2.00	0.33	9.5	$\rm 21.91^{22.31}_{20.68}$	42.23	AGN unabs
523	99.0	...	1.32	0.87-6.22	2.00	0.10	11.3	$\rm 22.98^{23.11}_{22.86}$	43.08	AGN abs
524	99.0	...	2.36	2.17-2.58	1.67	0.75	18.5	$\rm 23.39^{23.51}_{23.23}$	43.84	AGN abs
537	99.0	...	1.54	1.31-1.63	6.00	0.65	9.0	$\rm 22.62^{22.96}_{22.21}$	42.89	AGN abs
555	25.4	...	2.28	2.11-2.46	3.00	0.79	0.3	<22.68	42.83	AGN unabs
557	25.4	...	1.81	1.75-1.96	1.33	0.92	0.3	$\rm 22.66^{23.00}_{22.39}$	42.88	AGN abs
561	99.0	...	0.62	0.50-0.87	2.33	0.47	1.6	<21.38	41.82	galaxy
564	99.0	...	0.43	0.23-0.54	4.33	0.51	1.4	$\rm 21.79^{22.13}_{21.10}$	41.53	galaxy
572	27.0	...	2.73	2.21-2.68	2.00	0.53	1.8	$\rm 23.43^{23.68}_{23.17}$	43.62	AGN abs
583	99.0	...	2.77	2.66-2.88	1.00	1.00	2.2	$\rm 23.32^{23.49}_{23.11}$	43.77	AGN abs
589	99.0	...	1.33	0.89-6.51	2.00	0.10	1.2	$\rm 22.90^{23.11}_{22.57}$	42.81	AGN abs
593	25.9	...	2.07	1.83-2.15	2.67	0.77	0.6	$\rm 23.32^{23.61}_{22.95}$	43.31	AGN abs
599	25.2	...	2.84	2.48-2.82	1.33	0.76	1.9	$\rm 24.05^{24.17}_{23.92}$	43.99	AGN abs
605	99.0	...	4.71	4.39-4.83	5.00	0.85	8.2	$\rm 24.70^{24.93}_{24.49}$	44.52	QSO abs
$\rm 605A^{\ast}$	99.0	...	4.29	4.21-4.32	3.67	0.99	8.2	$\rm 24.70^{24.93}_{24.49}$	44.52	QSO abs
606	25.3	1.037	1.00	0.92-1.06	2.67	0.95	4.8	$\rm 23.27^{23.40}_{23.14}$	43.16	AGN abs
610	99.0	...	2.04	1.94-2.17	1.00	0.90	8.7	>24.18	43.87	AGN abs
614	99.0	...	1.13	0.60-1.57	4.33	0.27	19.8	$\rm 21.30^{21.93}_{20.62}$	42.67	AGN unabs
618	25.6	...	4.66	4.59-4.72	6.00	1.00	0.8	$\rm 23.86^{24.10}_{23.75}$	44.30	QSO abs
626	25.4	...	0.59	0.55-0.62	6.00	1.00	0.4	$\rm 22.45^{22.89}_{21.25}$	42.94	AGN abs
628	99.0	...	2.07	2.01-2.17	2.00	0.99	1.2	$\rm 23.93^{23.95}_{23.93}$	43.68	AGN abs
629	25.3	...	0.56	0.49-0.61	6.00	0.97	0.3	<22.37	41.39	galaxy

Source LaTeX | All tables | In the text

	1 Introduction
	2 The sample
	3 Comparison of the optically bright and optically faint X-ray source samples
	4 Photometric redshift technique applied to an X-ray selected sample
	5 The properties of OFS with spectroscopic redshifts
	6 X-ray-to-optical flux ratios
	7 X-ray spectroscopy
	8 X-ray absorbed QSOs
	9 Ultra deep field
	10 Conclusions
	References