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Table 1:   Summary of previous high angular resolution studies of 6.7 GHz methanol masers.

Table 2:   Sample of methanol masers observed with the EVN. The names are the Galactic coordinates of the brightest spot of each target obtained in post-processing EVN data. The dates of each observing run are listed in Table 4. The phase-calibrator names and angular separations from the targets are given.

Table 3:   Targets not detected with the MERLIN single baseline. The source names, coordinates, and peak flux velocities are taken from Szymczak et al. (2002).

Table 6:   Maser clusters towards 31 sources. If a spectrum of a maser cluster does not show a Gaussian profile we enter the sign - in the Cols. of FWHM and $S_{\rm amp}$.

 \begin{figure}\par\includegraphics[scale=0.9]{12250f10.eps} \end{figure} Figure 3:

The 8.4 GHz continuum emission detected using VLA on 2007 August 18. The names of radio continuum sources (RC) are the Galactic coordinates of peak fluxes. The peak and integrated fluxes as well as the levels of rms (1 $\sigma _{{\rm rms}}$) are given under each map and the beamsizes are presented at the left down corners. Contours trace the levels of 3 $\sigma _{{\rm rms}}$ $\times $ (1, 2, 4, 8, 16, 32, 64, ...).
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 \begin{figure} \par\includegraphics{12250f13.eps} \end{figure} Figure 6:

Spitzer IRAC 4.5 $\mu $m (grey) and 4.5 $\mu $m-3.6 $\mu $m (contour) images centered on selected methanol sources (at coordinates taken from Table 5). The grey scale in MJy sr-1 is indicated in the horizontal bar and contour levels are 1 MJy sr $^{-1}\times $ (1, 2, 4, 8, 16, 32, 64, 128). The methanol maser G21.407-00.254 coincides exactly with the brightest pixel in the 4.5 $\mu $m-3.6 $\mu $m image, at the map origin, which is offset from the 4.5 $\mu $m peak. There are at least two other nearby MIR sources with 4.5 $\mu $m emission excesses. Note the absence of further sources with extended 4.5 $\mu $m-3.6 $\mu $m emission excess in this 30 $^{\prime \prime }$ $\times $ 30 $^{\prime \prime }$  field. The maser source G24.148-00.009 coincides with the peaks of emission both at 4.5 $\mu $m and for the 4.5 $\mu $m-3.6 $\mu $m excess. The maser G37.598+00.425 is offset from the brightest 4.5 $\mu $m emission. Note the highly asymmetric morphology of the extended 4.5 $\mu $m-3.6 $\mu $m excess emission and the coincidence of the maser emission with a maximum of this excess. In the case of G38.203-00.067, the maser emission does not coincide with either of the two brightest sources but is close ($\sim $1 $.\!\!^{\prime\prime}$7) to a weak bump of 4.5 $\mu $m-3.6 $\mu $m excess located in a very extended arc ($\sim $25 $^{\prime \prime }$) of diffuse 4.5 $\mu $m emission. Further inspection of IRAC images at 5.8 $\mu $m suggests that this bump could be a weak MIR object.
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