24 new OH masers, 51 thermal emission and 4 absorption sources were detected during the second survey. The new masers are listed in Table 1 (click here). Column 1 contains IRAS names, or other names, if there is no associated IRAS source. Column 2 gives the galactic coordinates. Columns 3, 4 and 5 contain Gaussian fit results for the 1667 MHz line, and Cols. 6, 7 and 8 - for the 1665 MHz line. One sigma errors are given in parentheses. Right and left circular polarizations are designated by capitals R and L, while H and V stand for horizontal and vertical linear polarizations. Capital T is used when a line was supposed to be thermal, and a mean value of fluxes in both circular polarizations is given. When no line was detected, we give upper limits at the velocity position of the line measured in another polarization.
Most of the OH masers detected in this survey belong to type I, i.e. these are masers associated with star-formation regions with strongest emission in the OH main lines at 1665 and 1667 MHz, 1665 MHz being stronger than 1667 MHz.
Five of the masers resemble OH/IR stars: 17269-2235, 17416-2112, 17579-3121, 20361+5733, and 21432+4719 with typical double-peaked spectra at 1667 MHz. Although these sources formally satisfy Wood and Churchwell color criteria for ultracompact HII regions, they are very weak and the errors make their true colors uncertain.
Table 2 (click here) contains detections of thermal emission and absorption sources. In Col. 1, IRAS or other names are given, Col. 2 gives the association of an observed IRAS source with dark nebulae from the catalogue of Lynds. Galactic coordinates are listed in Col. 3. Columns 4, 5, 6 and 7 contain the results of Gaussian fits. All sources were observed in both two circular polarizations. Thus, for thermal sources, flux densities were determined from the mean of both polarizations. The LSR velocities and linewidths were determined from the mean of all four spectra (both circular polarizations at 1665 and 1667 MHz).
Column 8 yields the OH molecule column densities towards thermal
sources. Since the majority of these sources are very weak (mean flux density
0.15 Jy), and the principal goal of our survey was to detect new OH
masers, the integration time for many thermal sources was not sufficient for
good line parameter determination. Therefore we did not use parameters of two
OH lines at 1665 and 1667 MHz to determine OH column density (as in the
method described by Magnani et al. 1988) because the errors on the line
ratios were too large. For all detected thermal sources (except 05387-0924)
we used 1667 MHz data to determine the OH column density with the following
equations (assuming small optical depth):
with 
the observed brightness temperature
(obtained by
dividing the antenna temperature by the main beam efficiency
which equals
0.48 for the Nançay radiotelescope at zero declination, and supposing
that thermal sources are broader than the main beam), 
the
excitation temperature, 
K the temperature of the cosmic
background radiation, 
the rotational temperature, A the Einstein
value for the transition of frequency 
, 
and 
the
statistic weights of the upper and lower levels of a given transition,
the Full Line Width at Half Maximum (FWHM), N and
the total
OH column density and column density of molecules at the lower
level and 
,
the energy of the ground state 18-cm transition.
The statistical sum Z only includes the four lowest hyperfine
levels which give rise to OH lines at 18 cm. The energy of the next
rotational level with J = 5/2 in the 
ladder is about
85 
. This makes the excitation of this level negligible in the
cold clouds towards which we detected thermal OH emission. The excitation
temperature 
and the rotational temperature 
were
arbitrary taken equal to 5 K for all sources. 
does not cause
any serious error because the 
ratio is close
to zero for
any value of 
within the 5-100 K range. But changing
within these boundaries causes a change of 
by about
half an order of magnitude. Thus the values of 
in
Table 2 (click here)
must be regarded as rough estimates. Finally, Cols. 9 and 10 contain
radial velocity of the CO emission with the corresponding
references, and Col. 11 -
names of a associated IRAS cloud or core from Wood et al. (1994).