\begin{table}%t2
\caption{\label{table:2}Integrated flux density, root-mean-square noise levels, and derived dust temperature, power~law exponent of the opacity law, mass, and fractional dust luminosity for the 870-$\mu$m observations of main-sequence members of the~BPMG.}
\small%\centerline
 {
\begin{tabular}{l c c c c c c}
\hline\hline \noalign{\smallskip}
Target & Integrated flux density$^a$ $F$ & rms noise, $\sigma$ & $T_{{\rm dust}}$$^b$ & $\beta$ & Dust mass$^c$, $M_{\rm dust}$ & $f_{\rm dust}$ \\
 & (mJy) & (mJy/beam) & (K) &  & ($M_{{\rm Moon}}$) & ($10^{-4}$) \\
\hline
$\beta$~Pic & 63.6 $\pm$ 6.7 & 2.4 & 89 & 0.67 & 4.8 $\pm$ 0.5 & 17 \\
$\beta$~Pic (incl.~I) & 70.6 $\pm$ 8.2 &  & ... & ... & ... & ... \\
$\beta$~Pic (only II) & 15.8 $\pm$ 2.4 &  & ... & ... & ... & ... \\
HD~181327 & 51.7 $\pm$ 6.2 & 5.0 & 70 & 0.15 & 34 $\pm$ 4 & 27 \\
HD~172555 & 30 $\pm$ 10 (SE)$^d$ & 5.2 & 320+(10--20) & 0.1+0.1 & 10--60 (SE) & 10$^e$\\
 & 40 $\pm$ 10 (NW) &  & & & 20--70 (NW) & \\
HD~15115 & ... & 5.1 & 62 & 0.73$^f$ & ${<}2.9$ & 5.8$^f$\\
HD~164249 & ... & 4.0 & 70 & ... & ${<}2.2$ & 5.9$^g$\\
HD~181296 & ... & 4.8 & 150 & ... & ${<}1.3$ & 2.4$^g$ \\
HD~191089 & ... & 6.0 & 95 & ... & ${<}3.2$ & 19$^h$ \\
\hline
\end{tabular}}
\medskip
$^a$ The integrated flux density was calculated by fitting a Gaussian peak for HD~181327, $\beta$~Pic, and feature~II in the $\beta$~Pic map, while a circle of radius~$47\arcsec$ was used when including feature~I. For HD~172555 the flux was measured within the boxes in Fig.~\ref{fig:1all}c, as described in the text. Estimated errors come from rms~noise calculation in the specific integration region, together with an absolute calibration error of~10\% \citep{Siringo2009}. \\
$^b$  For detected sources we use the dust temperature derived from the best fit of the spectral energy distribution. For HD~15115 the best-fit temperature from \citet{Williams2006} is employed, while temperatures from IR~excess measured with IRAS \citep{Rhee2007} is used for the other objects. \\
$^c$ Upper $3\sigma$ limit on the dust mass for undetected sources. \\
$^d$ South-east and north-west feature of HD~172555 calculated separately. \\
$^e$ For a 15~K disk. \\
$^f$ From detection at 850~$\mu$m by \citet{Williams2006} who found $F_{850}=4.9$~$\pm$ $1.6$~mJy and derived a dust mass of~3.8~$M_{\rm Moon}$. \\
$^g$ From \citet{Rebull2008}. \\
$^h$ From \citet{Moor2006}.
\vspace*{0.5cm}
\end{table}