text:
\section{Introduction}

Nearly thirty years ago, the first discovery by Miller \& Antonucci (1983) of
broad permitted emission lines and a clearly non-stellar continuum in the
polarized spectrum of the archetypal Seyfert 2 (Sy2), NGC 1068, was just the beginning
of numerous similar observations in a wide variety of galaxies. Ten years
later, the unification model of active galactic nuclei (AGN)  was formulated upon these observations
(Antonucci 1993). According to the unification model, all AGN are intrinsically identical, while
the only cause of their different observational features is the
orientation of an obscuring torus with respect to our line of
sight. In more detail, the AGN type depends on the obscuration of
the broad line region (BLR), a small area at close proximity to the SMBH where the
broad permitted lines are produced. If the torus happens to be between the observer and the BLR, the optical emission and even the soft X-rays
are absorbed. Optical spectropolarimetric observations can reveal the hidden broad line region (HBLR) by
highlighting its scattered emission.
The observed narrow permitted emission lines are produced at far larger distances
from the core, where the torus is irrelevant.
As a prediction of this model, the presence and strength of the broad
optical emission lines, hence the derived optical spectral type (from type 1 AGN/Sy1s to type 2 AGN/Sy2s,
and the intermediate types), should correlate with the amount of intervening material as measured in X-rays.

X-ray observations can reveal the exact density of the obscuring torus, even for mildly obscured sources.
X-ray surveys with {\it Ginga} (Smith and Done 1996) and {\it ASCA} (Turner et al. 1997)
measured column densities between $10^{22}$ and up to a few times $10^{24}$ $\rm cm^{-2}$
in type 2 AGN samples. More recently, Akylas \& Georgantopoulos (2009)
and Brightman \& Nandra (2011), using {\it XMM-Newton},
and Jia et al. (2013, JJ13 hereafter), using {\it Chandra,} also studied
the obscuration of type 2 X-ray sources
in detail (see also Brandt \& Alexander (2015) for a recent review).
However, even in the hard X-ray band, the X-ray surveys may be
missing a fraction of highly obscured sources. These sources are called
Compton-thick AGN (see reviews by Comastri 2004 and Georgantopoulos 2013), and they present
very high obscuring column densities ($>10^{24} cm^{-2}$ , corresponding
to an optical reddening of $A_V>$100).  Even though Compton-thick
AGN are abundant in the optically selected samples of nearby Seyferts (e.g., Risaliti et al. 1999),
only a few tens of Compton-thick sources have been identified from X-ray data. Moreover, Krumpe et al. (2008)
found no Compton-thick QSO in their high redshift ($z>0.5$), X-ray selected sample, implying a possible redshift evolution, though
this may be due to selection.

Although the population of Compton-thick
sources remains elusive, there is concrete evidence of its presence.
The X-ray background synthesis models can explain the
peak of the X-ray background at 30-40 keV, where most of its
energy density lies, (Frontera et al. 2007; Churazov et al. 2007)
only by invoking a large number of Compton-thick AGN (Gilli
et al. 2007).  We note, however, that other models (e.g., Treister, Urry \& Virani 2009; Akylas et al. 2012)
succeed in explaining the X-ray background (XRB) spectrum assuming a lower fraction of CT sources.
Additional evidence of a Compton-thick
population comes from the directly measured space density
of black holes in the local Universe. It is found that this
space density could be up to a factor of two higher than predicted from
the X-ray luminosity function (Marconi et al. 2004). This immediately
suggests that the X-ray luminosity function is missing an
appreciable number of obscured AGN.

On the other hand, although widely accepted today, the unification model  cannot explain a series of
observations. For example, Tran et al. (2001) noticed the absence of a HBLR in polarized light in
many Sy2 galaxies (non-HBLR Sy2 galaxies), suggesting that there is a class of true Sy2 galaxies that intrinsically lack the broad-line
region (see Ho et al. 2008 for a review). Theoretical models attributed the absence of a BLR to either a
low Eddington ratio (Nicastro 2000) or to low luminosity (Elitzur \& Shlossman 2006).   Many studies
propose an evolutionary model where a fraction of Sy2 represents the first or the last phase in the
life of an AGN (Hunt \& Malkan 1999;
Dultzin-Hacyan, 1999; Krongold et al. 2002; Levenson et al. 2001; Koulouridis et
al. 2006a,b, 2013; Koulouridis 2014, Elitzur, Ho \& Trump 2014).
This was supported by studies of the local environment of Seyfert galaxies, which showed that
Sy2s reside in richer environments compared to Sy1s (e.g., Villaroel \& Korn 2014).
 Unobscured low-luminosity Sy2s were detected via investigation
of their X-ray properties (e.g., Pappa et al. 2000, Panessa \& Bassani 2002; Akylas \& Georgantopoulos 2009).
 Models of galaxy formation also support this scenario: for example, Hopkins et al. (2008)
assert that the AGN is heavily obscured during its birth. During the build-up of its
black hole mass, it blows away its cocoon, becoming an unobscured AGN.

In this paper, we compile a sample of bona fide optically selected Sy2 galaxies
using the SDSS spectra from the data release 10 (DR10).
   We cross-correlate our sample with the 3XMM/XMMFITCAT spectral catalog (Corral et al. 2015), which contains
   good quality spectra (at least 50 net counts per XMM detector).
   We identify a sample of 31 Sy2 galaxies with available X-ray spectra
   in the redshift range z=0.05-0.3.
   Our study is complemented by X-ray, mid-IR, and [OIII] luminosity ratio diagnostics
    (Georgantopoulos et al. 2013, Trouille \& Barger 2010).
   This study provides an extension of
   previous X-ray studies in the local Universe (e.g., Akylas \& Georgantopoulos 2009)
   but also of similar studies at higher redshifts (e.g., JJ13) because of the high S/N X-ray spectra used.

We describe our sample selection in \S2, the X-ray analysis in \$3, while our results
and conclusions are presented in \S4 and \S5, respectively. Throughout
this paper we use $H_0=72$ km/s/Mpc, $\Omega_m=0.27$, and
$\Omega_{\Lambda}=0.73$.

\section{Sample selection}

Our sample is composed of Seyfert 2 galaxies with available X-ray spectra within the XMM-Newton Serendipitous Source catalog
(Watson et al. 2009, Rosen et al. 2015) and
optical spectra within the SDSS-DR10.
The names of the sources are taken from the SDSS database. Also, a
sequence number is given to each source in the current paper (see Table 1). In the diagrams, interesting sources are followed by their sequence numbers.
In the text, the names are followed by the sequence number in parenthesis
to make it easier for the reader to trace the sources in the tables and the diagrams.

\begin{table*}
\begin{minipage}{155mm}
\caption{X-ray observations}
\tabcolsep 3 pt
\begin{tabular}{llccccccc}
N  &  name  &  obsid  &    ra  &  dec  &  z  & $\rm N_H (\times10^{22}$) & exposure time&  counts\\
{\em (1)}&{\em (2)}&{\em (3)}&{\em (4)}&{\em (5)}&{\em (6)}&{\em (7)}&{\em
(8)}&{\em (9)}\\
\hline
1  &    J080429.14+235444.1  &  504102101  &  121.1219  &  23.9127  &  0.07432  &  3.18  &    18300/--/--    &    86/0/0                               \\
2  &    J080535.00+240950.3  &  203280201  &  121.3961  &  24.1645  &  0.05971  &  3.08  &    5598/8425/--    &    125/83/0                            \\
3  &    J083139.08+524205.6   &  92800201  &  127.9131  &  52.7016  &  0.05855  &  1.16  &    60280/70920/71790    &    334/127/166                \\
4  &    J084002.36+294902.6  &  504120101  &  130.0095  &  29.8175  &  0.06481  &  1.83  &    17870/22630/22640   &   1072/424/428            \\
5  &    J085331.05+175339.0    &  305480301  &  133.3791  &  17.8942  &  0.18659  &  2.75  &    34560/--/--    &    173/0/0                           \\
6  &    J091636.53+301749.3   &  150620301  &  139.1524  &  30.2969  &  0.12339  &  1.25  &    9049/9392/--    &    431/151/0                         \\
7  &    J100129.41+013633.8  &  302351001  &  150.3724  &  1.6095  &  0.10423  &  3.07  &    31650/42310/42540    &    310/98/127                 \\
8 &    J101830.79+000504.9  &  402781401  &  154.6286  &  0.0845  &  0.06233  &  3.00  &    15700/20540/20600    &    753/398/397                  \\
9 &    J103408.58+600152.1    &  306050701  &  158.5360  &  60.0307  &  0.05101  &  1.51  &    8311/--/11420    &    465/0/133                         \\
10  &    J103456.37+393941.0  &  506440101  &  158.7349  &  39.6614  &  0.15081  &  1.96  &    68400/83070/83850    &    422/147/120              \\
11  &    J103515.64+393909.5  &  506440101  &  158.8154  &  39.6527  &  0.10710  &  2.03  &    --/83170/83870    &    0/112/ 92                          \\
12  &    J104426.70+063753.8  &  405240901  &  161.1109  &  6.6317  &  0.20991  &  3.02  &    24960/--/--    &    92/0/0                               \\
13  &    J112026.64+431518.4  &  107860201  &  170.1109  &  43.2554  &  0.14591  &  1.32  &    13870/--/--    &    182/0/0                             \\
14 &    J113549.08+565708.2   &  504101001  &  173.9555  &  56.9522  &  0.05112  &  1.07  &    17490/21310/21320    &    448/130/127              \\
15  &    J114826.24+530417.1    &  204260101  &  177.1089  &  53.0717  &  0.09826  &  1.23  &    1701/3632/--    &    112/94/0                         \\
16  &    J121839.40+470627.6  &  400560301  &  184.6649  &  47.1077  &  0.09390  &  1.00  &    --/37830/37570    &    0/86/137                  \\
17  &    J123056.11+155212.2  &  112552101  &  187.4978  &  13.5183  &  0.09816  &  2.31  &    8394/--/--    &    80/0/0                                     \\
18  &    J122959.45+133105.7    &  106061001  &  187.7338  &  15.87  &  0.18768  &  2.00  &    4660/--/8979    &    96/0/98                                  \\
19  &    J124214.47+141147.0   &  504240101  &  190.5607  &  14.196  &  0.15710  &  2.22  &    59590/--/80240    &    1465/0/665                       \\
20 &    J125743.06+273628.2   &  124710201  &  194.4296  &  27.608  &  0.06839  &  1.52  &    30010/--/--    &    119/0/0                                \\
21  &    J130920.52+212642.7  &  163560101  &  197.3359  &  21.4453  &  0.27858  &  1.57  &    --/28390/28700    &    0/191/215                       \\
22  &    J131104.66+272807.2   &  21740201  &  197.7694  &  27.469  &  0.23975  &  2.06  &    35000/43000/43100    &    267/73/75                     \\
23  &    J132525.63+073607.5  &  200730201  &  201.3567  &  7.6022  &  0.12402  &  5.02  &    26900/--/--    &    174/0/0                                \\
24  &    J134245.85+403913.6  &  70340701  &  205.6908  &  40.6537  &  0.08926  &  1.57  &    26010/35340/35100    &    393/220/216                \\
25  &    J135436.29+051524.5  &  404240101  &  208.6515  &  5.2564  &  0.08152  &  7.65  &    11020/--/15780    &    168/0/101                        \\
26  &    J141602.13+360923.2   &  14862010  &  214.0089  &  36.1567  &  0.17100  &  2.56  &    10910/15780/16140    &    271/146/145                   \\
27  &    J145720.44--011103.6  &  502780601  &  224.3353  &    --1.1844    &  0.08735  &  11.4  &    7942/--/--    &    71/0/0                               \\
28  &    J150719.93+002905.0   &  305750801  &  226.8330  &  0.4847  &  0.18219  &  10.5  &    9931/--/--    &    227/0/0                             \\
29  &    J150754.38+010816.8  &  402781001  &  226.9764  &  1.1381  &  0.06099  &  9.81  &    14330/17900/17890    &    222/81/81              \\
30  &    J215649.51--074532.4   &  654440101  &  329.2059  &    --7.7589    &  0.05541  &  5.22  &    42310/73600/75600    &    134/63/56             \\
31  &    J224323.18--093105.8  &  503490201  &  340.8464  &    --9.5185    &  0.14509  &  2.72  &    --/113700/114500    &    0/246/247                    \\
\hline
\end{tabular}
\tablefoot{{\em (1)} sequence number {\em (2)}, SDSS name,
{\em (3)} XMM-Newton observation ID number,
{\em (4)} spectroscopic redshift, {\em (5)} right ascension, {\em(6)} declination,
{\em (7)} Galactic column density in atoms/cm$^2$, {\em (8)} exposure time for the PN/MOS1/MOS2 detectors in seconds,
{\em (9)} counts on the PN/MOS1/MOS2 detectors.}
\end{minipage}
\end{table*}

\subsection{X-ray selection}

The XMM-Newton catalog is the largest catalog of X-ray sources ever built. Its current
version, 3XMM-DR4 (http://xmmssc-www.star.le.ac.uk/Catalogue/3XMM-DR4/), contains photometric information for half a million source detections, and
in addition, spectral and timing data for $\sim$ 120000 of them. The count limit adopted by the 3XMM-DR4 pipeline to derive spectral products
is of 100 EPIC net (background subtracted) counts, in order to allow reliable X-ray spectral extraction and analysis.

 The starting sample was extracted from the XMM-Newton/SDSS-DR7 cross-correlation presented in
Georgakakis \& Nandra (2011), including more
than 40000 X-ray sources. We first selected the sources detected in the X-ray hard band (2-8 keV), a band less
affected by obscuration than is the soft one (0.5-2 keV). A total of 1275 sources were found to have available optical spectra within SDSS-DR7. Out of these,
1018 sources had available 3XMM-DR4 spectral data. The corresponding SDSS optical spectra of
these 1018 sources were manually examined in order to identify Seyfert 2 galaxies, resulting in our final sample of Sy2s (see next section).
It is worth noting that two of these sources have more than one XMM-Newton observation with spectra within 3XMM-DR4, from which we used the longest one.

\begin{table*}
\begin{minipage}{175mm}
\caption{X-ray spectral analysis}
\tabcolsep 3 pt
\centering
\def1.3{1.3}
\begin{tabular}{lcccccccccccc} \\ \hline
N  &  $\rm N_H $  & $\Gamma_{soft}$  & $\Gamma_{hard}$   &  EW   &  flux  &  $L_X$ &  p1/p2 &  cstat/dof & $L_{[OIII]}$&$L_{12}$ & $L_{bol}$&log($M_{BH}$)\\
  &  $(\times10^{22}$)   &  &    &    &  $(\times10^{-14})$  &  $(\times10^{43})$ &  &  & $(\times10^{42})$&$(\times10^{43})$&$(\times10^{43})$&\\
{\em (1)}&{\em (2)}&{\em (3)}&{\em (4)}&{\em (5)}&{\em (6)}&{\em (7)}&{\em(8)}&{\em(9)}&{\em(10)}&{\em(11)}&{\em(12)}&{\em(13)}\\
\hline
1 &       $18.84_{-5.56}^{+7.68}$       &      $ 7.6_{-4.6}^{+7.6}$       &     1.8$\ddagger$     &$  <0.33      $                        &22.2&0.27&0.001&       105.2/96          &0.18       &   0.4   &  1.1 &  6.9        \\
2 &       $45.83_{-13.94}^{+21.30}$       &     $  2.4_{-0.4}^{+0.4}$       &  1.8$\ddagger$    & $  0.29_{-0.24}^{+0.71}$       &25.0&0.20&0.015&       165.25/210    &0.60                         &    0.2    & 0.3 & 6.8      \\
3 &       $23.56_{-3.79}^{+4.00}  $     &       $2.1_{-0.4}^{+0.4}$       &  $2.1_{-0.4}^{+0.4}$      & $  0.26_{-0.13}^{+0.20}$       &9.3&0.07&0.012&       537.63/618     &0.17                        &    0.7    &   1.0 & 6.3  \\
4 &       $54.24_{-5.82}^{+5.32} $      &       $2.8_{-0.1}^{+0.2}$       &   $ 1.4_{-0.7}^{+0.7}$      & $  0.30_{-0.80}^{+0.80}$       &69.7&0.63&0.024&       1088.68/1403    &1.11  &    8.8 & 19.9 & 7.6 \\
5 &       $26.38_{-20.54}^{+27.12} $      &      $ 2.5_{-0.7}^{+0.7}$ &  1.8$\ddagger$   &$  <0.17 $&17.8&1.20&0.293&       147.19/189              &5.77                                            &   11.4    & 25.9 & 7.9      \\
6 &       $<0.06         $      &      \multicolumn{2}{c}{$ 1.8_{-0.1}^{+0.2}$}   & $ <0.74  $                          &22.4&0.87&                &       425.68/522               &3.47       &   1.8    &      2.8    &    8.2  \\
7 &       $4.75_{-1.40}^{+1.28} $      &      $ 1.4_{-0.4}^{+0.4}$ &  $1.4_{-0.4}^{+0.4}$    &        $   0.29_{-0.17}^{+0.20}$       &15.6&0.39&0.018&       465.96/529      &0.07                      &   1.4    & 1.9 & 7.2      \\
8&       $2.34_{-0.32}^{+0.38}  $      &     \multicolumn{2}{c}{$1.5_{-0.2}^{+0.2}$}   & $  <0.10      $                        &60.1&0.54&                   &  825.83/1078     &0.04       &    0.3  &  0.4 & 6.2   \\
9$^\dagger$&       $30.32_{-11.62}^{+19.24} $      &      $ 2.9_{-0.2}^{+0.2} $      &  1.8$\ddagger$   &  $  1.30_{-0.48}^{+0.80}$       &17.8&0.07&0.293&       430.95/474    &4.98                     &    7.4   &  10.3 & 8.2  \\
10&       $64.58_{-23.33}^{+29.99} $      &      $ 3.0_{-0.2}^{+0.2}$ &    1.8$\ddagger$    &     $  0.52_{-0.25}^{+0.26}$        &4.1&0.20&0.102&       505.46/546    &5.37                    &   4.4   &  6.2 &  8.2   \\
11&       $14.35_{-5.85}^{+6.61}$       &      $ 6.3_{-1.5}^{+2.1}$&  $ 2.0_{-1.1}^{+1.2}$     &       $ <1.21   $                          &9.6&0.25&0.007&       189.43/210 &0.22   &   7.4    & 16.7 & 7.6        \\
12&       $90.26_{-48.60}^{+31.61} $      &      $ 1.5_{-0.9}^{+0.9}$       &  $1.5_{-0.9}^{+0.9}$ & $   <13.68  $                         &11.6&0.92&0.004&       82.28/98             &1.90            &   87.9    & 118.0  &  8.7        \\
13&       $5.49_{-2.51}^{+2.68} $      &      $ 1.3_{-0.7}^{+0.6}$       &   $1.3_{-0.7}^{+0.6}$   &  $   0.32_{-0.28}^{+0.85}$       &19.1&0.95&0.054&       140.57/186       &0.23                     &   2.8   & 6.3 &6.0           \\
14&       $130.46_{-56.34}^{+69.32}$       &     $  2.9_{-0.2}^{+0.2}$       &  1.8$\ddagger$   & $  <0.65     $                        &7.6&0.04&0.006&       434.45/462           &6.62           &    22.2  & 50.8 & 7.6   \\
15&       $1.92_{-0.69}^{+0.88}  $  &      \multicolumn{2}{c}{$ 1.8_{-0.5}^{+0.6}$}   &         $  <0.48  $                         &144&3.37&              &       169.96/204              &0.64      &   0.9    & 1.2  & 7.3       \\
16$^\dagger$&       $16.07_{-10.34}^{+39.22} $      &      $ 2.9_{-0.4}^{+0.4}$ &   1.8$\ddagger$     &      $ 0.85_{-0.66}^{+0.75}$        &7.9&0.16&0.173&       145.04/155    &5.47                    &   9.4 &  13.1  &  7.3  \\
17&       $4.83_{-2.48}^{+2.80}  $     &      $ 2.3_{-1.1}^{+1.0}$&   $2.3_{-1.1}^{+1.0}$    &$\star$&12.6&0.30&0.015&       82.11/85                   &2.06                                                  &   4.8   &   6.3  & 7.4      \\
18&       $1.81_{-0.87}^{+1.08} $  &    \multicolumn{2}{c}{$ 1.2_{-0.5}^{+0.5}$}    & $  <0.35  $                         &45.2&3.81&               &       183.1/184                &0.59      &   9.3  & 15.0 & 6.5      \\
19&       $<0.04                $      &      \multicolumn{2}{c}{$ 1.8_{-0.1}^{+0.1}$}   &  $  0.38_{-0.21}^{+0.21}$        &9.9&0.65&               &       748.87/885       &1.45              &   1.4     &  4.0  &      8.0    \\
20&       $12.62_{-7.20}^{+6.96} $      &       $1.7_{-1.1}^{+1.0}$       &   $1.7_{-1.1}^{+1.0}$     & $ 0.35_{-0.35}^{+0.51}$        &9.7&0.10&0.052&       140.82/167      &0.04                       &    0.3    & 0.4 & 5.9      \\
21&       $<0.08     $                 &      \multicolumn{2}{c}{$ 2.2_{-0.2}^{+0.2}$}    &$\star$&4.7&1.21&                &       214.46/247                         &0.10                                   &   0.5    &     0.5    &    6.9   \\
22$^\dagger$&       $243.07_{-115.26}^{+303.45}$      &     $ 2.6_{-0.2}^{+0.2}$     &  1.8$\ddagger$  &  $ 0.65_{-0.60}^{+0.81}$         &4.7&0.37&0.003&       296.79/365     &3.07                        &   11.7   &  23.3  &   7.8    \\
23&       $0.39_{-0.22}^{+0.39} $      &      \multicolumn{2}{c}{$ 1.5_{-0.4}^{+0.5}$}       &  $   <0.88$                          &16.5&0.62&              &       172.56/170         &0.13        &   0.4   &   1.1   &     7.4         \\
24&       $6.47_{-1.07}^{+1.31} $      &      $ 2.0_{-0.3}^{+0.4}$ &  $2.0_{-0.3}^{+0.4}$    &         $  0.17_{-0.13}^{+0.17}$       &41.1&0.77&0.009&       659.27/707       &0.26                     &   2.3    & 3.4 & 7.1     \\
25$^\dagger$&       $<0.07 $                      &      \multicolumn{2}{c}{$ 0.8_{-0.2}^{+0.2}$}  &$<0.70$&22.7&0.34&&       274.4/258             &0.16                                                      &   0.9    & 2.5 & 6.3           \\
26&       $1.98_{-0.47}^{+0.50} $   &   \multicolumn{2}{c}{$ 1.7_{-0.3}^{+0.3}$}  &  $  <0.37  $                          &46.5&3.47&               &       383.72/507                &1.48     &   42.3   &  97.8 & 8.1       \\
27&       $5.29_{-3.53}^{+4.69} $      &      \multicolumn{2}{c}{$ 1.6_{-1.1}^{+1.2}$}  &$<0.60$&13.1&0.23&                   &       97.74/80           &0.22                                       &   1.4       &   1.9 & 7.1             \\
28&       $28.78_{-12.22}^{+15.82} $      &      $ 1.7_{-0.7}^{+0.5}$      & $1.7_{-0.7}^{+0.5}$    & $  <0.46 $                          &34.6&2.56&0.045&       246.1/310           &10.66             &   2.4   & 32.3 & 8.8    \\
29$^\dagger$&       $32.18_{-12.68}^{+19.90}$       &     $  3.4_{-0.3}^{+0.4}$       & 1.8$\ddagger$    & $  1.22_{-0.73}^{+1.89}$       &10.6&0.09&0.155&       339.5/354    &1.71                         &    1.5  & 2.1 & 7.4    \\
30$^\dagger$&       $14.95_{-7.28}^{+11.92}  $     &       $3.6_{-0.4}^{+0.5} $       &   1.8$\ddagger$     &  $  2.08_{-1.24}^{+3.05}$       &3.8&0.03&0.280&       266.06/300    &0.96                   &    2.7   & 4.9 & 7.4      \\
31&       $2.61_{-0.68}^{+0.89} $    &     \multicolumn{2}{c}{ $ 1.3_{-0.3}^{+0.4}$}   &  $  <0.25  $                          &10.3&0.51&               &       355.49/417           &0.45      &   0.2   &  0.4 &   6.2         \\
\hline
\end{tabular}
\tablefoot{{\em (1)} sequence number, {\em (2)}, obscuring column density in atoms/cm$^2$,
{\em (3)-(4)} power-law photon index of the scattered and the continuum emission, respectively
(in the case of a single power-law fit. the value is listed in the middle of the two columns),
{\em (5)} equivalent width in keV of the FeK$\alpha$ line at 6.4 keV, {\em (6)} X-ray flux in $\rm erg\; s^{-1} cm^{-2}$, {\em
(7)} X-ray luminosity in $\rm erg\; s^{-1}$,
{\em (8)} the ratio of the scattered to the continuum emission normalization,
{\em (9)} C-statistics and degrees of freedom, {\em (10)} reddening-corrected [OIII] luminosity in $\rm erg\; s^{-1}$,
{\em (12)} AGN bolometric luminosity computed from the SED, {\em (13)}
black hole mass computed from the $M_{BH}-\sigma*$ relation.
\newline$\star$ Not constrained. \newline$\dagger$ See appendix for notes on individual objects. \newline $\ddagger$ Fixed $\Gamma_{hard}$.}

\end{minipage}
\end{table*}

\subsection{Optical selection}

We built the final Sy2 sample based on the emission line properties of their SDSS optical spectra. Initially,
we selected only emission line galaxies with redshifts between $z$=0.05 and $z$=0.35. The lower redshift limit excludes
all already extensively studied and well-known Seyferts (e.g., Akylas \& Georgantopoulos 2009), while the upper limit
ensures that the $\mathrm{H}\alpha$ and [NII] emission lines are within the SDSS spectral range.
Furthermore, we excluded all objects where the velocity dispersion of the $\rm H\alpha$ line is greater than 500 km/s,
since these objects are certainly broadline AGN. The rest of the objects were placed on a BPT diagram (Baldwin, Phillips, and Terlevich, 1981) and
star-forming galaxies, composite galaxies, and LINERS were removed according to the criteria of Kewley et al. (2001) and Schawinski et al. (2007).

We used the MPA-JHU emission line fluxes published in DR8 (Brinchmann et al. 2004; Tremonti et al. 2004), although DR10 also contains
data from the recent spectroscopic analysis of the Portsmouth Group (Thomas et al. 2013). However, the latter includes only
those galaxies from the first two years of observations of the SDSS-III/Baryonic Oscillation Spectroscopic Survey
(BOSS) collaboration. We note that a comparison between the two databases
by Thomas et al. (2013) has shown that the discrepancy between the calculated emission line fluxes is small. However, the comparison
was made after rescaling the Portsmouth values with a factor provided by the ``spectofiber'' keyword in the MPA-JHU database. This
rescaling was originally applied to the MPA-JHU data so that the synthetic r-band magnitude computed from the spectrum matches
the r-band fiber magnitude measured by the photometric pipeline.
The use of either database does not significantly affect the BPT diagram, since we only need the emission line ratios.

 We note that in some cases the broadening of the Balmer lines cannot be automatically detected (Seyfert 1.5, 1.8, and especially 1.9),
since it only affects the lower part of the lines. As a result, the automated modeling of the line by a single Gaussian may result in lower
velocity dispersion values than what is expected from a broad line profile, and the source may be misclassified as a narrow-line AGN.
However, since we sought a broad-line-free sample,
the spectra of all remaining AGN were eye-inspected with the ``interactive spectrum'' tool of the SDSS, and all evident intermediate-type
Seyferts were removed.
After the above filtering, the catalog of Sy2s included 40 objects.

Despite the above selection, a number of sources in our sample still have discrepant classifications in the literature;
i.e., eight of the sources are listed as Sy1s in Veron-Cetty \& Veron (2010, V\&V10 hereafter) catalog,
plus another one in the NED (NASA extragalactic database). Although none of these objects can actually be a Sy1,
we proceeded with our own optical spectrum analysis to determine whether there is any broadening of the permitted emission lines.

\subsection{Optical spectrum analysis}

The spectra have been retrieved from the SDSS-DR10 and corrected for Galactic extinction using the maps of Schlegel (1998).
We use the stellar population synthesis code \textmd{STARLIGHT}\footnote{http://www.starlight.ufsc.br/} to obtain the best fit to an observed
spectrum $O_{\lambda}$, taking the corresponding flux error into account. The best fit is a combination of single stellar populations (SSP)
from the evolutionary synthesis models of  (Bruzual 2003) and a set of  power laws to represent the AGN continuum emission.
Following the latter approach, several studies have been successful at disentangling the host galaxy and AGN emission components in SDSS
spectra (Cid-Fernandes 2011; Tavares 2011).

We use a base of 150 SSPs plus six power laws in the form F($\lambda$) = 10$^{20}$($\lambda$ / 4020)$^\beta$,
where $\beta$= -0.5, -1, -1.5, -2, -2.5, -3.  Each SSP spans six metallicities, Z = 0.005, 0.02, 0.2, 0.4, 1, and 2.5,
$Z_{\odot}$, with 25 different ages between 1~Myr and 18~Gyr. Extinction in the galaxy is taken into account in the synthesis,
assuming that it arises from a foreground screen with the extinction law of (Cardelli 1989). The code finds the minimum $\chi^{2}$,
\begin{equation}
 \chi^{2} = \sum_{\lambda} \left(  \frac{O_{\lambda}- M_{\lambda}} {\sigma_{obs}}\right)
,\end{equation}
where $M_{\lambda}$ is the model spectrum (SSP and power laws),
obtaining the corresponding physical parameters of the modeled
spectrum: star formation history, $x_{j}$, as a function of a base
of SSP models normalized at $\lambda_{0}$, $b_{j,\lambda}$,
extinction coefficient of predefined extinction laws,
$r_{\lambda}$, and velocity dispersion $\sigma_{\star}$, which obeys
the relation

  \begin{equation}
   M_{\lambda}= M_{\lambda 0} \left ( \sum_{j=1}^{N_{SSP}} x_{j}, b_{j,
   \lambda} r_{\lambda} \right) \otimes G(v_{\star}, \sigma_{\star})
  .\end{equation}

\noindent A detailed description of the \textmd{STARLIGHT} code can be found in the publications of the SEAGal
collaboration (Cid-Fernandes 2005 ; Cid-Fernandes 2007; Mateus 2006, Asari 2007). In Fig. 1 we present two
examples of the spectral decomposition results.

\begin{figure*}
\resizebox{18cm}{6cm}{\includegraphics{starlight_2.ps}}
\caption{Two examples of the optical spectrum analysis using STARLIGHT software.
We plot the observed spectrum (black), the host galaxy model spectrum (green), the modeled spectrum (red),
the AGN continuum emission (yellow), and the residual emission-line-spectrum (blue)}
\end{figure*}

After subtracting the stellar background, we use the commercial software {\tt PEAKFIT}, by {\it Systat Software Inc.}, to model the
emission lines. We analyze separately the red ($\rm H\alpha$, N[II] and S[II] emission lines) and the blue ($\rm H\beta$ and [OIII] emission lines)
parts of the spectrum. We initially model the emission lines in the blue part, since we are mostly interested in the profile
of the [OIII]${\lambda5007}$ narrow emission line, with which we also try to fit the lines in the blue part
and especially the $\rm H\alpha$. We model the [OIII] line with a mixed Gaussian and Lorentzian profile. The contribution of each profile to the fit
is a free parameter. If the same profile can also be applied to the red part of the spectrum, we consider this source
as a narrow line AGN and keep it in our sample. If there is still a need for an extra broad component to model the $\rm H\alpha$ the source is
discarded. In any case, the [NII]${\lambda6583}$/[NII]${\lambda6548}$ flux ratio should be $\sim3$.
We find that seven out of the 40 sources present a broad $\rm H\alpha$ component. Most of these sources belong to the list of ambiguous-type Seyferts that
we described in the previous section.

Finally, we plot the BPT diagram anew, this time with the line ratios calculated by the above spectral analysis. Although the differences are small,
we find that a source that was already close to the AGN-LINER separating line, falls in the LINER region and is therefore excluded. The BPT diagram
is plotted in Fig. 2.

\begin{figure}
\resizebox{9cm}{9cm}{\includegraphics{bpt.ps}}
\caption{BPT diagnostic diagram for the Sy2 sample. The various levels
of obscuration are color-coded. The continuous curve
denotes the star-forming - AGN separation line of Kauffmann et al. (2003), and the thick dashed curve the respective line of Kewley et al. (2001).
The dashed straight line denotes the LINER - AGN threshold by Schawinski et al. (2007). Composite or
transition objects (TO) between the AGN and star-forming phase are found in the area between the two curves. The open square indicates the position
of a discarded LINER.}
\end{figure}

\section{X-ray spectral fitting}

The X-ray data have been obtained with the EPIC (European
Photon Imaging Cameras, Str\"uder et al. 2001; Turner et al. 2001)
onboard XMM-Newton. X-ray photons are collected by
three detectors (PN, MOS1, and MOS2). All available instrument spectra are modeled simultaneously by using XSPEC,
the standard package for X-ray spectral analysis (Arnaud 1996).
We used Cash statistics (C-statistics), implemented as cstat in XSPEC to obtain reliable spectral-fitting results
even for the lowest quality spectra in our sample. Many of our sources were detected in only one or two
of the three detectors (see Table 1).

\renewcommand{\baselinestretch}{1.2}
The X-ray spectra of type 2 AGN are usually complicated
and consist of multiple components: power-law, thermal,
scattering, reflection, and emission lines (see Turner et al. 1997;
Risaliti 2002; Ptak et al. 2006; LaMassa et al. 2009). Therefore,
no single model could successfully fit the spectra in all cases. We initially
tried to model all spectra with a single absorbed power law, but if the
fit was not acceptable we added a second power law. Since a strong line is expected
in obscured sources, we fit a Gaussian line for the FeK$\alpha$ emission line in both cases.
In more detail, this includes:

\begin{itemize}

\item{Single absorbed power law plus Gaussian FeK$\alpha$ line.}\newline

We assumed a standard power-law model with two absorption
components (wabs*zwabs*pow in XSPEC notation) to fit the
source continuum emission. The first component models the Galactic absorption.
Its fixed values are obtained from
Dickey \& Lockman (1990) and are listed in Table 1. The second component represents the AGN intrinsic absorption
and is left as a free parameter during the modeling procedure. A Gaussian component has also been included to describe
the FeK$\alpha$ emission line. We fix the line energy at 6.4 keV in the source rest frame (except in the case of J090036.85+205340.3 (N6)
where the line was found at 6.7 keV and implies ionized Fe)
and the line width $\sigma$ at 0.01 keV ($\sim$10\% of the instrumental line resolution
of XMM-Newton). In 12 cases the fitting procedure gives a rejection probability less
than 90 per cent and we can accept the model. However,
when this simple parametrization is not sufficient to model the
whole spectrum, additional components must be included as described in the next paragraph.
\\
\item {Double power law plus Gaussian FeK$\alpha$ line.}\newline

 In the remaining 20 cases, an additional power law was necessary to obtain an acceptable fit (wabs*(pow+zwabs*pow), in XSPEC notation).
 The additional power law is only absorbed by the galactic column density.
Initially, the photon indices of the soft (scattered/unabsorbed) and hard (intrinsic/absorbed) power-law components were
tied together. However, in 13 cases the value of the hard power-law photon index $\Gamma_{hard}$ was too high
(the average photon index of the intrinsic power-law measured in AGN is usually $\sim1.8-2$),
and we needed to untie it from the soft one to obtain an acceptable fit. In the cases where the data quality was not high
enough to constrain $\Gamma_{hard}$, we fixed it to 1.8 (see Table 2).

\end{itemize}

The X-ray analysis revealed that one of the sources is the brightest galaxy
of a contaminating X-ray luminous cluster. We chose to exclude this source from our sample since
we cannot provide any reliable X-ray measurements. Our final sample comprises 31 Seyfert 2. In Fig. 3 we present some examples of the X-ray spectra of
unobscured ($<10^{22}cm^{-2}$, left panels) and strong FeK$\alpha$-line sources (right panels).

\begin{figure*}
\centering
\resizebox{18cm}{11cm}{\includegraphics{spectra.ps}}
\caption{Left panels: X-ray spectral modeling of two unobscured sources with a single power law. Right panels: X-ray spectral modeling of
two candidate Compton-thick sources with a double power law and an iron FeK$\alpha$ line.
The black points and the black line denote the PN detector, while the red line denotes the merged MOS1 and MOS2.}
\end{figure*}

\section{Results}

In the next sections we use various criteria and diagnostic diagrams
to investigate the possibility that some objects are more obscured than
we can infer from their $\rm N_H$ values and that Compton-thick candidate sources
are indeed heavily obscured.

\subsection{Candidate Compton-thick sources}

Only two of the sources have $\rm N_H>10^{24}$ cm$^{-2}$, consistent with the high values that define Compton-thick sources.
Also, sources (N10) and (N12) are consistent with being CT within the uncertainties. However, except for the column density as a direct indicator of obscuration, there
are other criteria, based not only on the X-ray but also on the
optical and the infrared emission, that could point to possible Compton-thick sources
within our sample. In more detail, a heavily obscured source can have one
or more of the following characteristics:

\begin{enumerate}
\item Flat X-ray spectrum ($\Gamma<1$). This implies the presence of a
strong reflection component that intrinsically flattens the
X-ray spectrum at higher energies (e.g., Matt et al. 2000).
\item High equivalent width of the FeK$\alpha$ line ($\sim$1 keV). In this case
a Compton-thick nucleus is evident since
the line is measured against a heavily obscured continuum
(Leahy \& Creighton 1993) or only against the reflected component.
\item Low X-ray to mid-infrared ($\rm L_{12}$) luminosity ratio.  All
Compton-thick sources should have low $\rm L_{2-10 keV}$ to $\rm L_{12}$ ratios, since
the mid-IR luminosity of an AGN should be dominated by very hot dust
and the X-ray emission should be suppressed by high amounts of absorption (e.g., Lutz et al. 2004; Maiolino et al. 2007).
\item Low X-ray to optical luminosity ratio. The [OIII] line emission originates in the narrow line
region and is not affected by the circum-nuclear obscuration.
Therefore, the ratio between the observed hard X-ray (2-10 keV) and
[OIII] line luminosity could be used as an indicator of the
obscuration of the hard X-ray emission (Mulchaey et al. 1994;
Heckman et al. 2005; Panessa et al. 2006; Lamastra et al.
2009; LaMassa et al. 2009; Trouille \& Barger2010).
\end{enumerate}

\subsubsection{Flat X-ray spectrum as an indicator of obscuration}

The first criterion of $\Gamma$ $<1$ is satisfied only by J135436.29+051524.5 (N25). However, this source
cannot be included in the Compton-thick candidate sources because there is evidence of partial covering.
For more detail see the notes on individual objects in the appendix.

\subsubsection{High equivalent width of the FeK$\alpha$ line as an indicator of obscuration}

The second criterion of a strong FeK$\alpha$ line is satisfied by four objects (see Table 2). Although the presence of the strong line provides robust
evidence of their obscuration, all four exhibit lower $\rm N_H$ values
than what is expected by a Compton-thick source. Therefore, we
also fit these sources with the model of Brightman \& Nandra (2011), which is based on Monte-Carlo simulations.
The advantage of this model is that it fits an iron line consistently with the computed $\rm N_H$. Thus, it cannot result in a good fit with
a low $\rm N_H$ value and at the same time a high-EW iron line, and vice versa.
The fitting confirms that these four sources are indeed Compton-thick. More details can be found in the notes on individual objects in the appendix.
Therefore, we do include them in our list of CT sources.

Also, we need to examine the X-ray spectra of the unobscured sources carefully for the FeK$\alpha$ line
that could give away the presence of obscuration. However, as we can see in Table 2, the line is actually detected only in one
out of the five sources, and the equivalent width (EW) is relatively small ($0.38^{+0.21}_{-0.21}$). We do not detect
the line in the spectra of any other unobscured source, and the given value of the EW is just the upper limit. Thus, there is no evidence of obscuration
based on the the presence of a FeK$\alpha$ line.

We note that this criterion is not explicit. High equivalent width
lines may also appear in the case of anisotropic distribution of the scattering medium
(Ghisellini et al. 1991) or in the case of a time
lag between the reprocessed and the direct component (e.g.,
NGC 2992, Weaver et al. 1996). On the other hand, Compton-thick sources
with FeK$\alpha$ EW well below 1 keV have been reported
(e.g., Awaki et al. 2000, for Mkn1210).

\subsubsection{The $L_X/L_{12}$ ratio as an indicator of obscuration}

The detection of a low X-ray to mid-IR luminosity ratio has
been widely used as the main instrument for detecting
faint Compton-thick AGN, which cannot be easily identified in
X-ray wavelengths (e.g., Goulding et al. 2011). This is because
the mid-IR luminosity (e.g., 12 $\mu $m or 6 $\mu $m) is a good proxy
for the AGN power because it should be dominated by very hot dust
that is heated by the AGN (e.g., Lutz et al. 2004; Maiolino et al. 2007).
At these wavelengths, the contribution of the stellar light and of colder dust heated by young stars should be small.
Gandhi et al. (2009) presented high angular resolution mid-IR (12 $\mu $m) observations
of the nuclei of 42 nearby Seyfert galaxies. These observations provide the least contaminated core fluxes of AGN.
These authors find a tight correlation between the near-IR fluxes and the intrinsic X-ray luminosity (the Gandhi relation).

Spitzer observations do not have the spatial resolution to resolve the core, and
the infrared luminosity of an AGN is probably contaminated
by the stellar background and the star-forming activity of the galaxy.
To obtain an estimate of the purely nuclear 12 $\mu $m infrared luminosity of our sources,
we constructed their spectral energy distributions (SED) and computed the various contributions.
To model the spectra we used optical data from the SDSS (five optical bands), photometry in the four
WISE bands (3.4, 4.6, 12, and 22 $\mu $m) (Wright et al. 2010), and photometry in the three 2MASS
bands (J, H, and K) for all sources. Although WISE does include the 12 $\mu $m band, we are only interested
in the AGN contribution, so that the construction of the SED and the decomposition of the AGN and host galaxy
component is essential. For more details about the code used, the interested reader should refer
to Rovilos et al. (2014, Appendix A).

In Fig. 4 we present the obscured X-ray luminosities against the 12 $\mu$m luminosities.
All our unobscured sources seem to follow the Gandhi-relation closely, and none of them shows
unusually high infrared luminosity compared to the X-ray. On the other hand,
candidate CT sources are found closer to the dashed line that demarcates the purely CT region.
The sources located below this line are all candidate CT according to our analysis.
Therefore, it is is unlikely that we are missing any CT candidates among the Sy2 sample.

\begin{figure}
\resizebox{9cm}{9cm}{\includegraphics{lxl12.ps}}
\caption{Absorbed X-ray (2-10 keV) X-ray luminosity against the 12$\mu$ m luminosity. Color- and shape-coding
as in Fig. 1. The typical errors are on the order of 30\% and 20\% for the IR and X-ray luminosity, respectively,
including the uncertainties in the model fitting. The hatched diagram represents the 1 $\sigma$
envelope of the local (Gandhi et al. 2009) relation. The dotted line corresponds to a factor of 30 lower X-ray
luminosity as is typical in many Compton-thick nuclei. The numbers of interesting sources
correspond to the sequence numbers in Tables 1 and 2.}
\end{figure}

\begin{table}
\begin{minipage}{87mm}
\caption{Candidate Compton-thick criteria}
\tabcolsep 3 pt
\begin{tabular}{lccccc}
N  &  name  & $\rm N_H$ & FeK$\alpha$ & $\rm L_x/L_{12}$ &  $\rm L_X/L_{[OIII]}$\\
{\em (1)}&{\em (2)}&{\em (3)}&{\em (4)}&{\em (5)}&{\em (6)}\\
\hline
9 &    J103408.58+600152.1    & $>10^{24}\dagger$ &  x        &  x   &  x   \\
10  &    J103456.37+393941.0  &   $>5\times10^{23}$ &  &      &     \\
12  &    J104426.70+063753.8  &   $>9\times10^{23}$ &  &  x   &     \\
14 &    J113549.08+565708.2   &   $>10^{24}$        &  &  x   &  x   \\
16  &    J121839.40+470627.6  &  $>10^{24}\dagger$  &  x         &  x   &   x \\
22  &    J131104.66+272807.2   &  $>10^{24}$   &       &      &  x \\
29  &    J150754.38+010816.8  & $>10^{24}\dagger$  &  x     &   &     \\
30  &    J215649.51--074532.4   & $>10^{24}\dagger$ & x    &  x  &  x \\
\hline
\end{tabular}
\tablefoot{{\em (1)} sequence number {\em (2)}, SDSS name,
{\em (3)} column density $\rm N_H$ in $cm^{-2}$, {\em (4)} sources with a strong FeK$\alpha$ line,
{\em (5)} sources located in the CT region of the $\rm L_x/L_{12}$ diagram, {\em (6)} sources located
out of the $3\sigma$ region of the $\rm L_X/L_{[OIII]}$ diagram.\\
$\dagger$ The column density of the source is calculated by the Brightman \& Nandra (2011) model (see appendix A).}
\end{minipage}
\end{table}

\subsubsection{The $\rm N_H$ vs. $L_x/L[OIII]$ ratio as an indicator of obscuration}

In this section we investigate the possibility that some of the sources are more obscured than we can infer from their column density.

\begin{figure}
\resizebox{9cm}{9cm}{\includegraphics{lxlo.ps}}
\caption{Distribution of the $\rm N_H$ values as a function of the
$L_{2-10 keV}/L_{[OIII]}$ ratio. Color- and shape-coding as in Fig. 1. The solid lines represent the mean
$\rm N_H$ vs. $L_{2-10 keV}/L_{[OIII]}$ relation followed by the Seyfert-1 sample in
Akylas \& Georgantopoulos (2009) assuming a photon index of 1.8 and
3\% (thin line: 1\%) reflected radiation (see also Maiolino et al. 1998; Cappi
et al. 2006), while the dashed lines represent the $\pm3\sigma$ dispersion.
The numbers of interesting sources correspond to the sequence numbers in Tables 1 and 2.}
\end{figure}

In Fig. 5 we plot the column density obtained from the
X-ray spectral modeling as a function of the X-ray to optical luminosity ratio.
The [OIII] luminosities are corrected for reddening
using the formula described in Basanni et al. (1999):
$\rm L_{[OIII]_{COR}} = L_{[OIII]_{OBS}} [(H\alpha /H\beta)/(H\alpha /H\beta)_o]^{2.94}$, where the intrinsic
Balmer decrement $\rm (H\alpha /H\beta )_o$ equals 3. The
lower left region in this plot could be possibly occupied by highly obscured
or Compton-thick AGN, although their $\rm N_H$ values show the opposite (Akylas \& Georgantopoulos 2009).
In our case, however, none of the unobscured sources is located in this region, and therefore there
is no evidence that their nuclei are heavily obscured.

On the other hand, three sources with $\rm N_H>10^{23}$ cm$^{-2}$ are found
marginally outside the 3$\sigma$ limit. This implies that they are probably even more
obscured than what we calculated by fitting their X-ray spectra. Interestingly, these are the three
out of four sources (J103408.58+600152.1 (N9), J121839.40+470627.6 (N16), J215649.51--074532.4 (N30))
for which a high FeK$\alpha$ EW is reported, and they are also found
below the CT line in Fig. 4. Therefore, despite
the value of the $\rm N_H$, it is evident that the iron line is a robust indicator of obscuration.
Once again we can infer that our classification of unobscured and CT sources is valid.

\section{Discussion and conclusions}

\subsection{Candidate Compton-thick sources}

X-ray spectroscopy shows that the number of Compton-thick AGN in our sample could be as high as eight.
N10 was initially included in the CT candidates because it is consistent with being CT within the uncertainties of the calculated column density.
However, we chose to exclude this source since it is not confirmed by any of the diagnostics presented in this study (see also LaMassa et al. 2014).
Therefore, we are left with seven CT sources, translating to a percentage of $\sim$23\%.

We find that the number of CT AGN found in our survey agrees with those in other X-ray surveys of optically selected Seyfert galaxies.
In more detail, Akylas \& Georgantopoulos (2009), using XMM-Newton observations, estimate the number of CT sources among the Seyfert galaxies from the
Palomar spectroscopic sample of nearby galaxies (Ho, Filippenko \& Sargent 1995). They find a percentage of CT sources of 15-20 \%.
Since their sample consists of nearby ($<$120 Mpc) Sy2 galaxies, the X-ray observations provide excellent spectra, hence accurate
column density measurements classifications of all the AGN in their sample. Also, Malizia et al. (2009) reports that $\sim18\%$ of their
hard X-ray selected Sy2 sample is Compton-thick. Nevertheless, considering only the low-redshift sources ($z<0.015$)
to remove the selection bias that affects their sample against the detection of CT objects, the percentage becomes $\sim35\%$.
They argue that this result is in excellent agreement with the percentage of CT AGN in the optically selected sample of Risaliti, Maiolino
\& Salvati (1999).
We note that because of our sample selection, which requires a sufficient number of photons in order to derive X-ray
spectra, we may also be biased against heavily obscured sources.

On the other hand, JJ13 in their SDSS optically selected sample of
type 2 QSOs, estimate a higher percentage of CT sources that could be as high as 50\%, albeit with limited photon statistics.
Initially, the percentage they calculate based on the X-ray spectral modeling and the intensity of the FeK$\alpha$ line is significantly lower. However,
it reaches 50\% after they conclude that at least half of the $\rm N_H$ values of their sources are underestimated,
based on their $L_{2-10 keV}/L_{[OIII]}$ ratios.

Nevertheless, four out of the seven CT sources in our study are in common with
JJ13. Three of them are also reported as CT in JJ13. N12 is not a CT source in JJ13 despite its high $\rm N_H$ and the detection of the FeK$\alpha$ line
in their work. A probable reason is that they report an X-ray luminosity that is one order of
magnitude higher than the one we measure in the current study. Therefore the $L_{2-10 keV}/L_{[OIII]}$ ratio is higher than their threshold
for a CT source.

We note that four sources in our sample were initially considered heavily obscured because of the high FeK$\alpha$ EW ($>$1 keV),
although their column density was only a few times $10^{23}$ $\rm cm^{-2}$.
This suggests that these sources may be attenuated by CT absorbers. Indeed, all CT sources in the local Universe appear to present
   high EW of the FeK$\alpha$ line (e.g., Fukazawa et al. 2011) owing to suppression of their continuum emission.
   The discrepancy between the estimated column density and the EW  could be attributed to a more complex spectral
   model that involves a double screen absorber with  one of them being
   CT. In all four cases, by fitting the X-ray spectra
  with the model of Brightman \& Nandra (2011), we confirm that they are indeed
  heavily obscured ($\rm N_H>10^{24} cm^{-2}$). In addition, according to Table 3, most of them satisfy all our CT criteria.
      Interestingly, three out of the above four high-EW sources, J103408.58+600152.1 (N9), J215649.51--074532.4 (N30), and
    J121839.40+470627.6 (N16) lie in the CT regime in the $\rm L_x/L_{12}$ diagram, and (Fig. 4) the same three sources
    have the lowest $\rm L_X/L_{[OIII]}$ ratios (Fig. 5), again supporting their CT nature. Two of these sources
    are in common with JJ13 (N9 and N16), and present a high EW in both studies.

\subsection{Unabsorbed Sy2 nuclei}

The X-ray spectral analysis revealed that four\footnote{We note that (N25) is a flat X-ray spectrum source with a visible
FeK$\alpha$ line, and we have excluded it from the list of unobscured sources (see appendix for more details)}
Sy2 galaxies ($\sim$13\%) present very low absorption, below $10^{22}$ cm$^{-2}$, in sharp contrast
with the unification model of AGN. The percentage of unobscured Sy2 sources varies in the literature, from a few percent ($\sim 3-4\%$)
in Risality, Maiolino \& Salvati (1999) and in Malizia et al. (2009), to 40\% in Page et al. (2006) and 66\% in Garcet et al. (2007). Our value
is in better agreement with Panessa \& Bassani (2002) and Akylas \& Georgantopoulos (2009). However, considering that the number of unobscured Sy2s
discovered in any of these studies is less than eight, we argue that we roughly agree with all of them, except perhaps with Garcet et al. (2007).
Also, we note that our criteria for selecting narrow line AGN are more stringent than in most of the above studies; for example,
Risality, Maiolino \& Salvati (1999) include Sy1.9 in their sample, and Garcet et al (2007) allow narrow line AGN up to FWHM$_{\mathrm{H}\alpha}$=1500 km s$^{-1}$.

As we have already
discussed, none of our unobscured sources present a low X-ray to
[OIII] or $\rm L_{12}$ luminosity ratio. They also do not present a strong FeK$\alpha$ line, and therefore we cannot
associate them with a highly obscured Compton-thick nucleus.
In addition, the FWHM of their $\mathrm{H}\alpha$ line is less than 500 km s$^{-1}$, which excludes the possibility
of a narrow-line Sy1 classification. Although Tran (2001) argues about the presence of this kind of type 2 AGN in his sample of
non-HBLR Sy2s fifteen years ago, their existence is still being strongly debated (see discussion in Antonucci 2012). Below, we summarize
important observational and theoretical studies in the field, which attempt to approach this problem from various
angles.

\begin{figure}
\resizebox{9cm}{9cm}{\includegraphics{bol.ps}}
\caption{Eddington ratio vs. bolometric luminosity plot. The open circles denote the unabsorbed Sy2s, and the filled ones the absorbed ones. Squares denote
the Compton-thick sources. The solid lines are the empirical thresholds found in the current work below which most of our unobscured Sy2s are found.
The dashed lines are the empirical thresholds shown in Marinucci et al. (2012) that separate HBLR and non-HBLR Sy2s.}
\end{figure}

There is strong evidence that the dusty obscuring torus in low luminosity AGN is
absent or is thinner than expected in higher luminosities (e.g., Elitzur \& Shlosman 2006; Perlman et al. 2007; van der Wolk et
al. 2010). Accordingly, all low luminosity AGN should have been Type 1 sources,
which of course is not the case. The only reasonable explanation of this problem
is the additional absence of the BLR in such systems.
Some authors (e.g., Nicastro 2000; Nicastro, Martocchia \& Matt 2003; Bian \& Gu. 2007; Marinucci et al. 2012; Elitzur, Ho \& Trump 2014)
presented arguments that below a specific accretion rate of material into the
black hole, and therefore at lower luminosities, the BLR might also be absent.

Using data from nearby bright AGN, Elitzur \& Ho (2009) conclude that the BLR
disappears at bolometric luminosities that are lower than $5 \times 10^{39} (M_{BH}/10^7 M_{\sun})^{2/3}
\rm erg\; s^{-1}$, where $M_{BH}$ is the mass of the black hole. They also argue
that the quenching of the BLR and the disappearance of the torus can occur
either simultaneously or in sequence, with decreasing black hole accretion rate and
luminosity. Thus, a possible scenario would be that non-HBLR Sy2 AGN are objects
lacking the BLR and possibly the torus. Nicastro, Martocchia \& Matt (2003) conclude
that the BLR probably does not exist below an accretion rate threshold of $\log(L_{bol}/L_{Edd})=-3$,
while Marinucci et al. (2012) argue that true Sy2s can be found below the relatively higher limits of
bolometric luminosity $\log L_{bol}=43.9$ and Eddington ratio $\log(L_{bol}/L_{Edd})=-1.9$.
Marinucci et al. (2012) derived the bolometric luminosity from the X-ray and the
[OIV] luminosity and conclude that $L_{[\rm OIII]}$ is not as reliable (see also relevant discussion in Elitzur 2012).
We note that Elitzur \& Ho (2009) thresholds are relatively low, not only compared to other studies but also for the general Sy2 population (see
discussion in the recent review by Netzer 2015). However, the idea that the accretion rate is essential in the formation of the BLR
seems to be valid, although the exact limits have not yet been defined and probably also depend on other factors (see discussion in Koulouridis 2014).

 To evaluate the above limits for our four unobscured sources, we computed their bolometric luminosities from the SED modeling (see \S4.2.4).
We also calculated their black hole masses using the $M_{BH}-\sigma*$ relation (Tremaine et al. 2002), where $\sigma*$ is the stellar velocity dispersion,
calculated from the FWHM of the [OIII] emission lines (Greene \& Ho 2005). We find that the Elitzur \& Ho (2009) limits are
very low for our unobscured sources. Nevertheless, all satisfy the bolometric luminosity and Eddington ratio limit
of Marrinucci et al. (2012). We note, however, that our Eddington ratios may be overestimated since the Eddington luminosities,
derived from the FWHM of the [OIII] lines, are probably underestimated (e.g., Bian \& Gu 2007).

By conducting a two-sample Student's t-test
between the accretion rates of the unobscured and the obscured sources, we conclude that their mean values are significantly different at the 99.9\%
confidence level. In Fig. 6 we plot the
Eddington ratio versus the bolometric luminosity of our Sy2s, but also the discarded intermediate type Seyferts (crosses).
We also plot the lines that apparently separate the unobscured sources from the rest of the Sy2
population. These limits are similar to the respective ones found by Marinucci et al. (dashed lines in Fig.6)
for HBLR and non-HBLR sources. All four unobscured sources fall into the area where non-HBLR Sy2s are found and the BLR is predicted to not exist. We note
that the limits of previous works were based on the differences between HBLR and non-HBLR Sy2s, while our sample is divided into obscured and unobscured
sources. The unobscured Sy2s are non-HBLR Sy2s by definition, whereas the obscured sources are not necessarily HBLR Sy2s.
Therefore, the presence of obscured Sy2s in the bottom left quarter of the plot may imply the lack of their BLR as well.
Interestingly, a number of Compton-thick sources exhibit low accretion rates. This agrees with the evolutionary scheme
of AGN proposed by Koulouridis (2014), where a fraction of Compton-thick
sources are predicted to emerge shortly after a galaxy interaction or merging event that causes the inflow of gas and dust toward
the central region of the galaxy,
enhances circumnuclear star formation and triggers the AGN. During this phase the accretion rate is expected to be low and the BLR absent.
However, the failure to detect the BLR in CT sources may as well be due to the heavy obscuration and the large covering factor
of the nucleus (see next paragraph).  We note that the uncertainties that enter the above calculations are large (see Greene \& Ho 2005) and
our samples fairly small. However, the general tendency of low accretion type-2 AGN to lack
any evidence of a BLR is once more evident.

An alternative scenario that can explain the lack of detectable BLR in many CT sources is that heavy obscuration does not
allow the detection of the BLR even in the polarized spectrum.
Marinucci et al. (2012) conclude that 64\% of
their compton-thick non-HBLR Sy2s exhibit higher accretion rates than the
threshold clearly separating the two Sy2 classes. They attributed this
discrepancy to heavy absorption along our line of sight, preventing the
detection of the actual BLR in their nuclei. Evidently, merging systems constitute
a class of extragalactic objects where heavy obscuration occurs (e.g., Hopkins et
al. 2008). The merging process may also lead to rapid black hole growth, giving
birth to a heavily absorbed and possibly Compton-thick AGN. Thus, we could
presume that a number of our non-HBLR mergers, if not all of them, might actually be
BLR AGN galaxies, where the high concentration of gas and dust prohibits even
the indirect detection of the broad line emission (e.g., Shu et al. 2007). However, other studies
have concluded that there is no evidence that non-HBLR Sy2s are more obscured than their HBLR peers (Tran 2003; Yu 2005; Wu 2011), while
totally unobscured low-luminosity non-HBLR Sy2s were detected via investigation
of their X-ray properties (e.g., Panessa \& Bassani 2002; Akylas \& Georgantopoulos 2009). The total population of non-HBLR Sy2s
is probably a mixture of objects with low accretion rate and/or high obscuration.

Koulouridis (2014) argue that both of the above scenarios agree with an AGN evolutionary scheme
(Krongold et al. 2002; Koulouridis et al. 2006a, b, 2013),
where a low accretion rate is predicted at the beginning and the end of the Seyfert
duty cycle, without ruling out the possibility that some HBLR Sy2s
could also be created by minor disturbances or even secular processes.

Finally, we note that there is always the possibility that the discrepancy
between the optical and the X-ray spectra is due to variability, since they were not obtained
simultaneously.\\

In a nutshell:
\begin{enumerate}
 \item We found four unobscured sources ($\sim$13\%) at odds with the simplest unification scheme. These
 sources exhibit low accretion rates that agree with previous studies that predict the lack of the BLR in low-accretion-rate AGN.
 \item 64\% of the Sy2s are obscured with a median column density value of $\rm N_H\sim1.0\times10^{23}cm^{-2}$.
 \item The percentage of CT AGN is at $\sim$23\%,
although direct comparison with previous studies is difficult because of the different selection methodologies.
Their heavy obscuration was confirmed using a variety of criteria and diagnostics.
\end{enumerate}

\acknowledgements
We thank the anonymous referee for the insightful comments and suggestions that significantly contributed to improving the quality of the publication.
EK acknowledges fellowship funding provided by the Greek General Secretariat of Research
and Technology in the framework of the program Support of Postdoctoral
Researchers, PE-1145.
This work is based on observations obtained with XMM-Newton, an ESA science
mission with instruments and contributions directly funded by ESA Member States
and the USA (NASA). Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the
Participating Institutions, the National Science Foundation, and the U.S.
Department of Energy Office of Science. The SDSS-III web site is
http://www.sdss3.org/.

redpajama_set_name: RedPajamaArXiv


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text:
<?php

namespace Facebook\Tests;

use Facebook\Facebook;
use Facebook\FacebookClient;
use Facebook\Http\GraphRawResponse;
use Facebook\HttpClients\FacebookHttpClientInterface;
use Facebook\PersistentData\PersistentDataInterface;
use Facebook\Url\UrlDetectionInterface;
use Facebook\PseudoRandomString\PseudoRandomStringGeneratorInterface;
use Facebook\FacebookRequest;
use Facebook\Authentication\AccessToken;
use Facebook\GraphNodes\GraphEdge;

class FooClientInterface implements FacebookHttpClientInterface
{
    public function send($url, $method, $body, array $headers, $timeOut)
    {
        return new GraphRawResponse(
            "HTTP/1.1 1337 OK\r\nDate: Mon, 19 May 2014 18:37:17 GMT",
            '{"data":[{"id":"123","name":"Foo"},{"id":"1337","name":"Bar"}]}'
        );
    }
}

class FooPersistentDataInterface implements PersistentDataInterface
{
    public function get($key)
    {
        return 'foo';
    }

    public function set($key, $value)
    {
    }
}

class FooUrlDetectionInterface implements UrlDetectionInterface
{
    public function getCurrentUrl()
    {
        return 'https://foo.bar';
    }
}

class FooBarPseudoRandomStringGenerator implements PseudoRandomStringGeneratorInterface
{
    public function getPseudoRandomString($length)
    {
        return 'csprs123';
    }
}

class FacebookTest extends \PHPUnit_Framework_TestCase
{
    protected $config = [
        'app_id' => '1337',
        'app_secret' => 'foo_secret',
    ];

    /**
     * @expectedException \Facebook\Exceptions\FacebookSDKException
     */
    public function testInstantiatingWithoutAppIdThrows()
    {
        // unset value so there is no fallback to test expected Exception
        putenv(Facebook::APP_ID_ENV_NAME.'=');
        $config = [
            'app_secret' => 'foo_secret',
        ];
        $fb = new Facebook($config);
    }

    /**
     * @expectedException \Facebook\Exceptions\FacebookSDKException
     */
    public function testInstantiatingWithoutAppSecretThrows()
    {
        // unset value so there is no fallback to test expected Exception
        putenv(Facebook::APP_SECRET_ENV_NAME.'=');
        $config = [
            'app_id' => 'foo_id',
        ];
        $fb = new Facebook($config);
    }

    /**
     * @expectedException \InvalidArgumentException
     */
    public function testSettingAnInvalidHttpClientHandlerThrows()
    {
        $config = array_merge($this->config, [
            'http_client_handler' => 'foo_handler',
        ]);
        $fb = new Facebook($config);
    }

    public function testCurlHttpClientHandlerCanBeForced()
    {
        $config = array_merge($this->config, [
            'http_client_handler' => 'curl'
        ]);
        $fb = new Facebook($config);
        $this->assertInstanceOf(
            'Facebook\HttpClients\FacebookCurlHttpClient',
            $fb->getClient()->getHttpClientHandler()
        );
    }

    public function testStreamHttpClientHandlerCanBeForced()
    {
        $config = array_merge($this->config, [
            'http_client_handler' => 'stream'
        ]);
        $fb = new Facebook($config);
        $this->assertInstanceOf(
            'Facebook\HttpClients\FacebookStreamHttpClient',
            $fb->getClient()->getHttpClientHandler()
        );
    }

    public function testGuzzleHttpClientHandlerCanBeForced()
    {
        $config = array_merge($this->config, [
            'http_client_handler' => 'guzzle'
        ]);
        $fb = new Facebook($config);
        $this->assertInstanceOf(
            'Facebook\HttpClients\FacebookGuzzleHttpClient',
            $fb->getClient()->getHttpClientHandler()
        );
    }

    /**
     * @expectedException \InvalidArgumentException
     */
    public function testSettingAnInvalidPersistentDataHandlerThrows()
    {
        $config = array_merge($this->config, [
            'persistent_data_handler' => 'foo_handler',
        ]);
        $fb = new Facebook($config);
    }

    public function testPersistentDataHandlerCanBeForced()
    {
        $config = array_merge($this->config, [
            'persistent_data_handler' => 'memory'
        ]);
        $fb = new Facebook($config);
        $this->assertInstanceOf(
            'Facebook\PersistentData\FacebookMemoryPersistentDataHandler',
            $fb->getRedirectLoginHelper()->getPersistentDataHandler()
        );
    }

    /**
     * @expectedException \InvalidArgumentException
     */
    public function testSettingAnInvalidUrlHandlerThrows()
    {
        $config = array_merge($this->config, [
            'url_detection_handler' => 'foo_handler',
        ]);
        $fb = new Facebook($config);
    }

    public function testTheUrlHandlerWillDefaultToTheFacebookImplementation()
    {
        $fb = new Facebook($this->config);
        $this->assertInstanceOf('Facebook\Url\FacebookUrlDetectionHandler', $fb->getUrlDetectionHandler());
    }

    public function testAnAccessTokenCanBeSetAsAString()
    {
        $fb = new Facebook($this->config);
        $fb->setDefaultAccessToken('foo_token');
        $accessToken = $fb->getDefaultAccessToken();

        $this->assertInstanceOf('Facebook\Authentication\AccessToken', $accessToken);
        $this->assertEquals('foo_token', (string)$accessToken);
    }

    public function testAnAccessTokenCanBeSetAsAnAccessTokenEntity()
    {
        $fb = new Facebook($this->config);
        $fb->setDefaultAccessToken(new AccessToken('bar_token'));
        $accessToken = $fb->getDefaultAccessToken();

        $this->assertInstanceOf('Facebook\Authentication\AccessToken', $accessToken);
        $this->assertEquals('bar_token', (string)$accessToken);
    }

    /**
     * @expectedException \InvalidArgumentException
     */
    public function testSettingAnInvalidPseudoRandomStringGeneratorThrows()
    {
        $config = array_merge($this->config, [
            'pseudo_random_string_generator' => 'foo_generator',
        ]);
        new Facebook($config);
    }

    public function testMcryptCsprgCanBeForced()
    {
        if (!function_exists('mcrypt_create_iv')) {
            $this->markTestSkipped(
                'Mcrypt must be installed to test mcrypt_create_iv().'
            );
        }

        $config = array_merge($this->config, [
            'persistent_data_handler' => 'memory', // To keep session errors from happening
            'pseudo_random_string_generator' => 'mcrypt'
        ]);
        $fb = new Facebook($config);
        $this->assertInstanceOf(
            'Facebook\PseudoRandomString\McryptPseudoRandomStringGenerator',
            $fb->getRedirectLoginHelper()->getPseudoRandomStringGenerator()
        );
    }

    public function testOpenSslCsprgCanBeForced()
    {
        if (!function_exists('openssl_random_pseudo_bytes')) {
            $this->markTestSkipped(
                'The OpenSSL extension must be enabled to test openssl_random_pseudo_bytes().'
            );
        }

        $config = array_merge($this->config, [
            'persistent_data_handler' => 'memory', // To keep session errors from happening
            'pseudo_random_string_generator' => 'openssl'
        ]);
        $fb = new Facebook($config);
        $this->assertInstanceOf(
            'Facebook\PseudoRandomString\OpenSslPseudoRandomStringGenerator',
            $fb->getRedirectLoginHelper()->getPseudoRandomStringGenerator()
        );
    }

    public function testUrandomCsprgCanBeForced()
    {
        if (ini_get('open_basedir')) {
            $this->markTestSkipped(
                'Cannot test /dev/urandom generator due to open_basedir constraint.'
            );
        }

        if (!is_readable('/dev/urandom')) {
            $this->markTestSkipped(
                '/dev/urandom not found or is not readable.'
            );
        }

        $config = array_merge($this->config, [
            'persistent_data_handler' => 'memory', // To keep session errors from happening
            'pseudo_random_string_generator' => 'urandom'
        ]);
        $fb = new Facebook($config);
        $this->assertInstanceOf(
            'Facebook\PseudoRandomString\UrandomPseudoRandomStringGenerator',
            $fb->getRedirectLoginHelper()->getPseudoRandomStringGenerator()
        );
    }

    /**
     * @expectedException \InvalidArgumentException
     */
    public function testSettingAnAccessThatIsNotStringOrAccessTokenThrows()
    {
        $config = array_merge($this->config, [
            'default_access_token' => 123,
        ]);
        $fb = new Facebook($config);
    }

    public function testCreatingANewRequestWillDefaultToTheProperConfig()
    {
        $config = array_merge($this->config, [
            'default_access_token' => 'foo_token',
            'enable_beta_mode' => true,
            'default_graph_version' => 'v1337',
        ]);
        $fb = new Facebook($config);

        $request = $fb->request('FOO_VERB', '/foo');
        $this->assertEquals('1337', $request->getApp()->getId());
        $this->assertEquals('foo_secret', $request->getApp()->getSecret());
        $this->assertEquals('foo_token', (string)$request->getAccessToken());
        $this->assertEquals('v1337', $request->getGraphVersion());
        $this->assertEquals(
            FacebookClient::BASE_GRAPH_URL_BETA,
            $fb->getClient()->getBaseGraphUrl()
        );
    }

    public function testCanInjectCustomHandlers()
    {
        $config = array_merge($this->config, [
            'http_client_handler' => new FooClientInterface(),
            'persistent_data_handler' => new FooPersistentDataInterface(),
            'url_detection_handler' => new FooUrlDetectionInterface(),
            'pseudo_random_string_generator' => new FooBarPseudoRandomStringGenerator(),
        ]);
        $fb = new Facebook($config);

        $this->assertInstanceOf(
            'Facebook\Tests\FooClientInterface',
            $fb->getClient()->getHttpClientHandler()
        );
        $this->assertInstanceOf(
            'Facebook\Tests\FooPersistentDataInterface',
            $fb->getRedirectLoginHelper()->getPersistentDataHandler()
        );
        $this->assertInstanceOf(
            'Facebook\Tests\FooUrlDetectionInterface',
            $fb->getRedirectLoginHelper()->getUrlDetectionHandler()
        );
        $this->assertInstanceOf(
            'Facebook\Tests\FooBarPseudoRandomStringGenerator',
            $fb->getRedirectLoginHelper()->getPseudoRandomStringGenerator()
        );
    }

    public function testPaginationReturnsProperResponse()
    {
        $config = array_merge($this->config, [
            'http_client_handler' => new FooClientInterface(),
        ]);
        $fb = new Facebook($config);

        $request = new FacebookRequest($fb->getApp(), 'foo_token', 'GET');
        $graphEdge = new GraphEdge(
            $request,
            [],
            [
                'paging' => [
                    'cursors' => [
                        'after' => 'bar_after_cursor',
                        'before' => 'bar_before_cursor',
                    ],
                ]
            ],
            '/1337/photos',
            '\Facebook\GraphNodes\GraphUser'
        );

        $nextPage = $fb->next($graphEdge);
        $this->assertInstanceOf('Facebook\GraphNodes\GraphEdge', $nextPage);
        $this->assertInstanceOf('Facebook\GraphNodes\GraphUser', $nextPage[0]);
        $this->assertEquals('Foo', $nextPage[0]['name']);

        $lastResponse = $fb->getLastResponse();
        $this->assertInstanceOf('Facebook\FacebookResponse', $lastResponse);
        $this->assertEquals(1337, $lastResponse->getHttpStatusCode());
    }
}

redpajama_set_name: RedPajamaGithub


text:
Words under fire: When libraries become targets
When those in power want to control access to history and ideas, libraries are often the first to be targeted, reports Rachael Jolley
BY RACHAEL JOLLEY
Raghad Hammadi, who is a member of a group of students campaigning to help rebuild the Central Library of Mosul University, is seen in Mosul. Photo: Reuters/Khalid Al-Mousily
Almost three decades ago, some three million books and countless artefacts went up in flames when Sarajevo's National and University Library – inside the Vijecnica (city hall) – was burned to the ground. The destruction of the Vijecnica at the beginning of the war was a symbol for one of the aggressor's main objectives – silencing the soul of the city and crushing the cultural identity of an entire society."
So said Dunja Mijatović, the current Council of Europe commissioner for human rights, who was born in Sarajevo when it was part of Yugoslavia.
Just weeks before the anniversary of the burning of the library on 25 August 1992, Mijatović spoke to Index about its symbolism and what its destruction was meant to achieve.
She quoted Heinrich Heine's play, Almansor: "Where they burn books they will also, in the end, burn people."
Libraries and archives have been targets for centuries, and the reason is always the same: it's about taking away knowledge and stifling free thinking.
Libraries are, and have always been, symbols of freedom – the freedom to think and learn and find documents and books to debate and discuss.
Throughout history, when authoritarians take power and seek to control thought and behaviour, they either lock up libraries or destroy the manuscripts and books inside them.
The Serbian forces who burned the Sarajevo library were seeking to obliterate evidence of Bosnia and Herzegovina's existence as a successful multicultural and multi-ethnic state. The documents they burned told a different history from the one that the army leaders wanted to portray.
Omar Mohammed, who reported as Mosul Eye on the Isis occupation of his city in Iraq, risked his life to blog anonymously about the occupiers' wish to destroy books as well as to execute people as they sought to repress the population.
Mohammed told Index that it was not just the university library that was destroyed in Mosul, but it was the one that was reported on the most.
Many other libraries, even private collections, were wiped out. "The only possible reason is because knowledge is power," he said. "Once you prevent people from accessing knowledge then you will have full control over them."
Like many other scholars who have delved into the history of libraries, Mohammed understands that it is not about the buildings themselves.
"They don't want people to have this access because they know if people write the history, it will be completely different from the one they wanted it to be," he said.
Targeting libraries sends out a powerful message to scholars, historians and scientists, he added.
"When they see that such people are able to totally target the libraries, that they are literally able to destroy everything, it's a manifestation of brutality."
Today, Richard Ovenden, the most senior librarian at the Bodleian libraries at the University of Oxford, is worried about libraries in Turkey being closed under pressure from the government of president Recep Tayyip Erdoğan.
According to some sources, at least 188 libraries were closed there between 2002 and 2020.
Ovenden's book, Burning the Books, looks at the history of the intentional destruction of knowledge. He was recently contacted by a Turkish student, who said: "I've just read your book and I want you to know how bad it is in Turkey, because libraries are being destroyed. And all the things that you write about are true in Turkey today."
Ovenden said: "There is an absolutely authoritarian control over knowledge. Attacks on knowledge are being exercised by the authoritarian leader of Turkey right now. It is the ability for the population to generate their own ideas and to come up with their own thoughts that some governments, some authoritarian powers, some dictators and rulers do not like."
When dictatorships seek to establish that certain minorities don't exist, or haven't lived somewhere, getting rid of the documentary evidence is very convenient.
Archives that establish the existence of Uighurs in China and Muslims in parts of India also look like targets.
Ovenden feels that what is fantastically important about libraries is that they "preserve the past thoughts and ideas of human beings so they're parts of that evidence base".
He added: "They're also disseminating institutions [where] you can borrow the books, you can come and take those ideas away and write other books about them, or pamphlets, or newspaper articles, or whatever it is."
Governments around the world are failing to protect libraries as a resource, sometimes by withdrawing or drastically reducing funding.
In the UK, almost 800 libraries closed between 2010 and 2019, and a major campaign kicked off in Australia this year to save the national archives.
Michelle Arrow, professor of history at Macquarie University in Sydney, argued in April that if funding cuts were not reversed, irreplaceable audio-visual collections would fall apart. After a public campaign, the national government has delivered some extra funding, but this has not solved all the archives' problems.
She told Index that with a reduction in staff of almost 25% since 2013, more staff would be needed to deal with the large backlog of requests to view archived material.
She said the archives contained "unique records, and they touch almost every Australian: it is a democratic archive, a collection of ordinary people's records, rather than famous or renowned Australians".
While some countries are seeing numerous library closures due to financial or other threats, there are new defenders coming to light. In the coastal city of Santa Cruz in California, there's a massive investment in upgrades to current libraries, and new ones are opening over the next two years.
Santa Cruz mayor Donna Meyers told Index: "In California, we just tend to believe in public institutions. We believe that public education, public libraries, all of that, lead to a better community, lead to a more informed society."
Santa Cruz residents passed a special tax – by 78% of the vote – to pay for investment in the libraries which, Meyers says, is a sign of how committed the community is to libraries being around for future generations.
Back in Sarajevo, Mijatović can see the new library that rose from the ashes of the Vijecnica from her terrace.
She said: "One hopes that the soul and the people of Sarajevo will recover and that new generations will hopefully enjoy this magnificent symbol of Sarajevo and, more importantly, live in peace."
Library destruction in recent history
1914: German troops destroy the library of the Catholic University of Louvain
1939: The Great Talmudic Library in Lublin is destroyed by the Nazis
1966-76: Chairman Mao destroys libraries across China as part of the Cultural Revolution
1976-79: The Khmer Rouge deliberately destroy libraries across Cambodia, including the Phnom Penh national library
2013: Islamic troops set fire to the library in Timbuktu, Mali
Rachael Jolley
Rachael Jolley is a former editor-in-chief of Index on Censorship magazine. Having started as a news reporter on a regional newspaper, she moved on to writing for magazines, newspapers and websites in the UK and internationally (including The Times, the Financial Times and The Guardian). She has been editorial director at think tank British Future, managing editor for monthly magazine Business Traveller, and editor of Business Traveller Middle East, as well as Head of Online for the Fabian Society. She writes regularly for the New Statesman and other publications and co-wrote the play Murdering The Truth (Greenwich Theatre).
Latest posts by Rachael Jolley (see all)
Words under fire: When libraries become targets - 24 September
Why journalists need emergency safe havens - 6 August
Editor's letter: All hail those who speak out - 17 September
One response to "Words under fire: When libraries become targets"
Glynis Waghorn says:
4 October at 01:28
Knowledge is power, that's why controlling governments/people want others kept away from too much learning, especially learning the truth about history.

redpajama_set_name: RedPajamaCommonCrawl


Local author Debora M. Coty, who is also a columnist for the Christian Voice Monthly pens new book from her popular book series Too Blessed to be Stressed.
The job description reads—long hours, frequently disgruntled patrons, no paid vacations and zero upward mobility. Sound like a dream job? Welcome to the joys of motherhood.
Coty, also an inspirational speaker, recognized the need and niche for the book after years of fielding questions from frustrated matriarchs through speaking engagements and emails.
Her latest addition to the series provides practical tips built on biblical truths to help mothers manage their stress and appreciate the blessings in the daily grind.
Applying different animals to depict Diana Baumrind's four parent styles, Coty presents the subject in a way any mother can relate.
Too Blessed to Be Stressed for Moms officially releases on September 1 but is available for pre-order now. All of Coty's books are available for purchase at Amazon.com, Christianbooks.com and Barnes & Noble.
Coty and husband Chuck reside in the Seffner area. They have two grown children and four grandchildren.
The inspirational speaker and humorist has authored more than 40 books. To connect with Coty and check out some of her stress buster videos, visit www.deboracoty.com.


A pair of sparrows balance on a thin branch in front of a stylized botanical background on this square pillow. This design by Marjolein Bastin is embellished with a sweet embroidered detail—one of the birds holds fragile stems of blue wildflowers in its beak.
Square fabric pillow with embroidered design.
To clean, wipe with damp cloth.
I purchased both of the new spring pillows for my deck. I have many of Miss Bastin's products and am a fan. I bought both the butterfly and bird pillows (I especially liked the bird) but when I got them home, the background of the bird was far too yellowish, and screamed at the mint greens on my porch. I, sadly, returned for another butterfly pillow, but really wanted to have one of each....and now I see I could have gotten for almost $10. price reduction on-line. A bit disappointing.
Review 1 out of 5 stars.
European house sparrows are an invasive, non-native species in the United States. They will kill native small nesting birds such as chickadees, purple martins and downy woodpeckers. They compete with these species for nesting cavities. They are very damaging and not a protected species. DO NOT BUY THIS PILLOW.


text:
Q: Rails generator para nested resources estava pesquisando mas não encontrei nenhum generator para nested resources no Rails. Alguém saberia me dizer se conhece algum?

A: Henrique, não existe gerador de nested resources, mas o Rails te facilita muito a fazer isso na mão.
Para o caso de Article has many Comments, você basicamente precisaria alterar:
a) Os models:
class Article < ActiveRecord::Base
  has_many :comments
end

class Article < ActiveRecord::Base
  belongs_to :article
end

b) As rotas:
resources :articles do
  resources :comments
end

c) E, finalmente, os controllers: (essa parte pode ser mais tricky)
comments_controller.rb
class CommentsController < ApplicationController
  def index
    @article = Article.find(params[:article_id])
    @comments = @article.comments
  end

  def new
    @article = Article.find(params[:article_id])
    @comment = @article.comments.build
  end

  def create
    @article = Article.find(params[:article_id])
    @comment = @article.comments.build(params[:comment])
    if @comment.save
      flash[:notice] = "Successfully created comment."
      redirect_to article_url(@comment.article_id)
    else
      render :action => 'new'
    end
  end

  def edit
    @comment = Comment.find(params[:id])
  end

  def update
    @comment = Comment.find(params[:id])
    if @comment.update_attributes(params[:comment])
      flash[:notice] = "Successfully updated comment."
      redirect_to article_url(@comment.article_id)
    else
      render :action => 'edit'
    end
  end

  def destroy
    @comment = Comment.find(params[:id])
    @comment.destroy
    flash[:notice] = "Successfully destroyed comment."
    redirect_to article_url(@comment.article_id)
  end
end

articles_controller.rb
class ArticlesController < ApplicationController
  def index
    @articles = Article.find(:all)
  end

  def show
    @article = Article.find(params[:id])
    @comment = Comment.new(:article => @article)
  end

  def new
    @article = Article.new
  end

  def create
    @article = Article.new(params[:article])
    if @article.save
      flash[:notice] = "Successfully created article."
      redirect_to @article
    else
      render :action => 'new'
    end
  end

  def edit
    @article = Article.find(params[:id])
  end

  def update
    @article = Article.find(params[:id])
    if @article.update_attributes(params[:article])
      flash[:notice] = "Successfully updated article."
      redirect_to @article
    else
      render :action => 'edit'
    end
  end

  def destroy
    @article = Article.find(params[:id])
    @article.destroy
    flash[:notice] = "Successfully destroyed article."
    redirect_to articles_url
  end
end

Seguindo o modelo ilustrado acima você não deveria ter problemas =)
Qualquer dúvida mais específica, você pode fazer uma nova pergunta!

redpajama_set_name: RedPajamaStackExchange


text:
Home » International Trade » Russia / USA » US – Sanctions/Export Highlights [As Of June 30, 2022].
US – Sanctions/Export Highlights [As Of June 30, 2022].
Russia Sanctions: This week the United States designated dozens of additional entities and individuals as Specially Designated Nationals ("SDNs"). Notable designations included State Corporation Rostec ("Rostec"), a large Russian state-owned company that operates in the automotive, defense, aviation, and metal industries; individuals who were part of a covert procurement network linked to Russia's Federal Security Service (the "FSB"); the Interregional Social Organization Union of Donbas Volunteers, a veteran organization which has been recruiting fighters and providing direct support to the Russian military; and several Russian defense companies. The Department of State also announced steps to impose visa restrictions on 511 Russian Federation military officers for "authorizing actions that threatened or violate the sovereignty, territorial integrity, or political independence of Ukraine" and on 18 Russian Federation officials for "suppressing dissent in Russia and abroad."
The UK designated an additional eight individuals and five entities. The individuals designated include Vladimir Potanin, Russia's second wealthiest man and owner of Rosbank PJSC, and Anna Tsivileva, the President of JSC Kolmar Group, a Russian coal mining company.
General Licenses: The United States issued several new General Licenses ("GLs"). GL 39 authorizes wind-down transactions involving Rostec until August 11, 2022. GL 40 authorizes transactions ordinarily incident and necessary to ensure the safety of civil aviation involving certain blocked entities for aircraft registered outside of Russia and operated solely for civilian purposes. GL 41 authorizes transactions ordinarily incident and necessary to the manufacture, sale, and maintenance of agricultural equipment, components, and spare parts produced by Nefaz Publicly Traded Company or Public Joint Stock Company Tutaev Motor Plant, through December 22, 2022. GL 42 authorizes limited transactions with the FSB. GL 43 authorizes transactions that are ordinarily incident and necessary to (i) the divestment or transfer of debt or equity from, or (ii) the wind-down of certain derivative contracts with, Public Joint Stock Company Severstal or Nord Gold PLC through August 31, 2022. The UK issued GL INT/2022/1968500, which allows a 30-day wind-down period of positions involving Rosbank PJSC.
G7 Summit: The G7 issued a statement condemning Russia's war in Ukraine and pledged to expand cooperation in intelligence sharing and information security, provide humanitarian assistance, support refugees from Ukraine, and intensify economic sanctions.
Exports and Imports: The United States increased the "Column 2" duty rates to 35% ad valorem on certain Russian products classified within hundreds of specified harmonized tariff codes. Column 2 duty rates are rates for countries that do not have normal trade relationships with the United States. The United States also prohibited the importation of Russian gold into the United States. Additionally, the United States issued temporary denial orders against three Russian airlines – Nordwind Airlines, Pobeda Airlines, and S7 Airlines – for operating in violation of U.S. export control laws. Finally, the U.S. Department of the Treasury's Financial Crimes Enforcement Network ("FinCEN") and Commerce's Bureau of Industry and Security ("BIS") issued a joint alert advising financial institutions to remain vigilant against attempts to evade export controls.
BIS Updates: BIS made several announcements this week regarding the agency's policies. BIS highlighted four changes to its administrative enforcement program: (i) the imposition of significantly higher penalties; (ii) using non-monetary resolution for less serious violations; (iii) eliminating "No Admit, No Deny" settlements, and (iv) dual track processing of voluntary self-disclosures. BIS also announced a new "Academic Outreach Initiative" to help academic institutions comply with export control laws. The initiative will have four main components (i) strategically prioritized engagement; (ii) assignment of "Outreach Agents" for prioritized institutions; (iii) background briefings for foreign universities; and (iv) trainings for prioritized academic research institutions.
BIS also added six entities, Connec Electronic Ltd.; King Pai Technology Co., Ltd; Sinno Electronics Co., Ltd.; Winninc Electronic; World Jetta (H.K.) Logistics Limited; and Promcomplektlogistic Private Company, to the Entity List because they "contracted to continue to supply Russian military end users" and this activity is "contrary to U.S. national security and foreign policy interests under § 744.11(b) of the EAR.
Anand Sithian, Crowell & Moring
US – Contractors May Mark Unlimited Rights Technical Data So Long As The Government's Rights Are Not Impermissibly Restricted: A Study In Contrasts.
US – Second Circuit Gives Renewed Hope To Account Holders Seeking To Access Their Funds Trapped In Lebanese Banks—But Is It Only A Glimmer?


text:
<?xml version="1.0" encoding="utf-8"?>
<resources>

    <style name="my_edittext_style" parent="@android:style/Widget.EditText">
        <item name="android:background">@drawable/superid_my_edittext</item>
    </style>

</resources>


Occupational therapy is one sort of treatment of prescripted therapies from the catalogue of the health insurences, which is prescribed by a doctor.
The financing is usually provided by health insurances, social security or privatly.
The aim of all occupational therapy interventions is the rehabilitation, conservation, development, improvement or compensation of disease-related motoric, sensoric,psycatric,cognitive functions and abilities.
Occupational therapy has influence on the individual action-competence in daily life, social field, school, education or in job.
Occupational therapy works with complex enabling and action-oriented methods and proceedings using adapted training material, functional, playful, artisanal, creative techniques and practical life exercises.
Moreover, occupational therapists give advice concerning school-, workplace-,living area and environmental adaptions.
Occupational therapy can take place in form of individual or group therapy.
According to the medical indication, it is possible to prescribe visits to private homes nursing or residential facilities.
A brain-performance training or neurologic-orientated treatment, is a specific Therapy which treats illness-related disorders of neuropsychologic brainfunctions, especially incapacities that are the result of cognitive dyfunctions.


text:
Fear of discrimination arises after act was passed
Last week, Indiana Gov. Mike Pence signed the Religious Freedom Restoration Act into law.
Under the law, businesses are able to cite their religious freedom as a legal defense for if they get sued for discrimination.
The law also states that the government cannot "substantially burden a person's exercise of religion" and if a proprietor feels that his or her religious beliefs have been burdened he or she can cite the law to fend off lawsuits.
Since the signing of the bill, people have raised concerns over whether or not the bill allows businesses to discriminate based on sexual orientation.
Some worry that business owners may refuse service to people based on their sexual orientation and cite the law as a way to justify that discrimination.
Pence, due to the backlash of the RFRA, is now working to re-word the bill to bar discrimination.
While the governor stated that he did not intend the law to cause such backlash, I share the concern with many others, that as it stands right now, the RFRA has opened its doors to allow discrimination.
Indiana is not the only state with a law like this on its books. Nineteen states have religious freedom laws modeled after the federal Religious Freedom Restoration Act from 1993.
Any private business may reserve the right to refuse service under this law. It might make it easier for businesses to get away with discrimination if sued.
Arkansas, following Indiana's lead, passed its own religious freedom act on Tuesday, March 31.
Most of the states that passed religious freedom laws did so before gay marriage became legal in their states. For a bill that is not supposed to be discriminatory it sure seems as if state legislators are using the bill to do just that.
US vs. Irish COVID protocol
Celebrating holidays during a pandemic
Coronavirus outbreaks in Erie
Netflix price raise is unethical
International relations at stake in this election
Pope and I support same-sex couples
Should we favor Electoral College or popular vote?
Write-ins and third party votes a waste
Grief of missing Hurst Day this year
Saying no to Amy Coney Barrett


iRealHousewives | The 411 On American + International Real Housewives: Kameron Westcott Reacts To Brandi Redmond's 'No Talent' Comment And Weighs In On The Drama At Stephanie Hollman's Halloween Party!
Kameron Westcott Reacts To Brandi Redmond's 'No Talent' Comment And Weighs In On The Drama At Stephanie Hollman's Halloween Party!
Kameron Westcott is taking to her Bravo Blog to dish on this week's episode of The Real Housewives of Dallas. Kameron Westcott weighs in Stephanie Hollman's Halloween party and reacts to Brandi Redmond's 'no talent' comment.
Bravotv.com: How do you teach your daughter how to be girly yet powerful? Why is that important to instill?
Kameron Westcott: Even today in 2017 we still live in such a male dominated society and there is this misconception that you can't be feminine and also successful and respected. I teach Hilton to not be afraid to be herself and not change just because that's the status quo. It's important to instill confidence in my daughter because her potential is limitless and the future is female. She needs know that she has the power to make the world conform to her and not the other way around.
Bravotv.com: Why do you think Court is so skeptical about the dog food business?
KW: Pink dog food is actually not my first business, for years I have made dog clothes and sold them to boutiques in Dallas. I was extremely passionate about it, but it never really got enough momentum to take off. On a side note, I still don't get why women don't want to buy more dresses for their small boy dogs but moving on...Court is skeptical because that is his job as a venture capitalist and will continue to be until I stop talking about it and actually show him some results.
Bravotv.com: What were you thinking when Brandi Redmond said you didn't have a talent?
KW: I was like, wait did I hear that right, did she really just say what I thought she said? I mean who says stuff like that? I think the answer is someone who is insecure about themselves and or intimidated. While it does annoy me that she said something so mean, I actually feel sorry for her and would love to help her learn to have less of a need to put other people down to make her feel better about herself.
Bravotv.com: What do you think about Stephanie Hollman and Brandi's make-up conversation?
KW: Hmmm, that's tough, but I probably side with Brandi on this. Brandi went through some hard stuff over the last year and when your dirty laundry is in public the last thing you want is your best friend to light it on fire. But I am glad they were able to amend their issues and am happy that they are friends again.
Bravotv.com: What do you think of LeeAnne Locken's costume as Stephanie and the drama between the ladies?
KW: While I love LeeAnne, if she came dressed as me in a negative way to my party I would have had the exact same reaction that Travis did and I would have asked her to leave. At the same time, if it was at a neutral site, there may be some truth to what LeeAnne was trying to convey and I hope soon her and Stephanie have the chance to work through their issues in a less toxic manner.
Bravotv.com: Do you think LeeAnne is right to worry that without Brandi the group will turn on her?
KW: As we all know LeeAnne, rightfully so, has had abandonment issues in her past, so that has to be extra hard for her to see Brandi and Steph become friends again because she may be over analyzing and thinking that if they get back together, she may lose her. So I think she is less worried about the group turning on her and more worried of no longer having Brandi in her life.