4 Notes on individual sources

4.1 New detections

Here we give brief notes on many individual sources. We have checked against existing surveys of maser and thermal lines, and surveys of 5 GHz continuum in the galactic plane in order to look for any associations.
05382+3547. We detected the 6.7 GHz methanol feature at velocity 0-24.1 km s^-1. The CO(1-0) emission was found towards this source at -19.2 km s^-1 and possibly at -10.2 km s^-1 (Wouterloot & Brand 1989).
06061+2151. The methanol features at velocities -8.7 and -5.5 km s^-1 lie well within the velocity range -13 to 0 km s^-1, where strong water maser emission was observed (Wouterloot et al. 1993). The CO (1-0) line at velocity -1.6 km s^-1 found by Wouterloot & Brand (1989) is slightly redshifted relative to the methanol line. Molinari et al. (1996) found the ammonia lines at -0.5 km s^-1.

18061-1927. We found the methanol emission in the velocity interval 14 to 18 km s^-1. Codella et al. (1995) detected the water maser line at 24.5 km s^-1.
18111-1729. Walsh et al. (1997) did not found the methanol emission with a 3 $\sigma$ detection limit of 1 Jy. We detected a 6.4 Jy feature at 48.5 km s^-1. This suggests that the source is variable. It is likely that the source is associated with CO emission at 54 km s^-1 quoted by Jaffe et al. (1981). The water masers were found at quite different velocities of -21 km s^-1 (Jaffe et al. 1981) and -1.6 km s^-1 (Cesaroni et al. 1988).

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Figure 1: The 6.7 GHz methanol maser spectra for all detections listed in the paper

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18141-1626. The methanol emission of this source is peaked at 27 km s^-1 and is within the velocity interval of methanol emission from 18141-1615 located about $11^{\prime}$ away. At a position $~3\hbox{$.\mkern-4mu^\prime$ }1$ from the source, Jaffe et al. (1981) found H₂O maser with the main feature at 37 km s^-1.
18155-1554. van der Walt et al. (1995) failed to detect the methanol emission from this source to an upper limit of $\sim$ 5 Jy. Backer et al. (1994) found an ultracompact HII region with the flux density of 88.5 mJy at 5 GHz.
18264-1152. Bronfman et al. (1996) detected the CS(2-1) emission at 43.6 km s^-1 that is close to the velocity of 46.8 km s^-1, where we found a single methanol feature.
18278-1009. We detected the methanol emission at 116.6 km s^-1. Molinari et al. (1996) found the ammonia lines at 94 and 98 km s^-1.
18282-1024. This source has an associated ultracompact HII region with the flux density of 96.2 mJy at 5 GHz (Backer et al. 1994).
18305-0826. van der Walt et al. (1995) did not detect the methanol emission to an upper limit of $\sim$ 5 Jy. Easy detection of the methanol maser in our survey suggests that the source is variable.
18321-0854. Towards this source Codella et al. (1995) found the water maser emission at 79 km s^-1 that is well within the velocity range of methanol emission from 72 to 83 km s^-1. Methanol emission at velocities lower than 76 km s^-1 appears to come from 18324-0855.
18324-0855. The methanol maser spectrum from this sources is contaminated by emission from 18321-0854. Both sources were observed at the same epoch and we conclude that only emission at velocities lower than 76 km s^-1 comes from 18324-0855.
18326-0802. This source probably coincides with an ultracompact HII region with the flux density of 32.6 mJy at 5 GHz (Backer et al. 1994).
18337-0707. An ultracompact HII region with the flux density of 110 mJy at 5 GHz was found towards this source (Backer et al. 1994).
18372-0537. Bronfman et al. (1996) found the CS(2-1) line at 111.5 km s^-1 that is near to the velocity of the methanol feature at 107.1 km s^-1. This source is associated with an ultracompact HII region with the flux density of 70.6 mJy at 5 GHz (Backer et al. 1994).
18372-0541. We detected the methanol emission at 24.6 km s^-1 that is virtually the same as the velocity of CS emission (23.6 km s^-1) observed by Bronfman et al. (1996). The source has an associated ultracompact HII region with the flux density of 76.1 mJy at 5 GHz (Backer et al. 1994).
18391-0504. An ultracompact HII region with the flux density of 53.1 mJy at 5 GHz was possibly detected towards this source (Backer et al. 1994).
18402-0403. With a probability of 0.86 this source is associated with 5 GHz emission of 49.5 mJy (Backer et al. 1994).
18441-0134. This source has an associated ultracompact HII region with the flux density of 3.6 mJy at 5 GHz (Backer et al. 1994).
18454-0136. The CS(2-1) emission found at 38.9 km s^-1(Bronfman et al. 1996) is very close to the methanol feature detected here at 40.8 km s^-1. Backer et al. (1994) identified an ultracompact HII region with the flux density of 14.7 mJy at 5 GHz.
18527+0301. Towards this source the ammonia lines were found (Molinari et al. 1996) at 76 km s^-1, i.e. exactly within the methanol emission velocity range 70 to 85 km s^-1.
18577+0358. We detected the methanol emission in the velocity interval 49 to 63 km s^-1. The CS(2-1) emission was found at 52.9 km s^-1(Bronfman et al. 1996). The H₂O maser emission is centred at 45 km s^-1(Hofner & Churchwell 1996). Towards this source two ultracompact HII regions with flux densities of 42.5 and 345.3 mJy at 5 GHz were found (Backer et al. 1994).
18592+0426. The CS(2-1) emission was found at 83.5 km s^-1(Bronfman et al. 1996), whereas we observed the methanol emission in the velocity range from 69 to 71 km s^-1. An ultracompact HII region of the flux density of 21.3 mJy at 5 GHz was found (Backer et al. 1994).
19048+0705. H₂O maser was found at 66.7 km s^-1 (Scalise et al. 1989), whereas we found a methanol feature at 63.4 km s^-1.
19097+0847. We detected the methanol emission at 58.8 km s^-1, while Bronfman et al. (1996) found the CS(2-1) emission at 57.3 km s^-1. The H₂O maser emission is centred at 50 km s^-1(Hofner & Churchwell 1996).
19191+1538. Bronfman et al. (1996) found the CS(2-1) emission at 25.8 km s^-1 that is close to the velocity interval of methanol emission from 26 to 33 km s^-1.
19266+1745. The methanol line at 10 km s^-1 is near to the CS(2-1) emission at 5 km s^-1 found by Bronfman et al. (1996).
19282+1814. The methanol emission at 18.7 km s^-1 is likely to be associated with a source of the CS(2-1) emission at 23.6 km s^-1(Bronfman et al. 1996) and the ammonia lines at 24.1 km s^-1(Molinari et al. 1996).
19366+2301. The CS(2-1) emission found at 32.9 km s^-1(Bronfman et al. 1996) is well within the velocity interval of methanol emission from 31 to 36 km s^-1.
19437+2410. The CS(2-1) emission found at 4.9 km s^-1(Bronfman et al. 1996) is near to the velocity of the methanol feature at 3.6 km s^-1.
20110+3321. We found the methanol emission at 4.0 and 10.7 km s^-1. The H₂O maser emission was detected in the velocity range from 13.6 to 18.6 km s^-1 with the peak flux of 72 Jy at 16.4 km s^-1, whereas the 1667 MHz OH maser line was found at 7.4 km s^-1(Lewis & Engels 1993).
21413+5442. The methanol emission was found at -61.6 km s^-1in the survey. The 1612 and 1665 MHz OH emission was reported at -61 km s^-1 (Cohen et al. 1988). The excited OH maser emission at 4765 MHz (Cohen et al. 1991) and at 6035 MHz (Baudry et al. 1997) was found near -62 km s^-1. Scalise et al. (1989) reported the H₂O maser centred at about -60 km s^-1. The CO(1-0) emission was found at -64 km s^-1 (Wouterloot & Brand 1989). The CS(2-1) emission at the same velocity was reported (Bronfman et al. 1996).
22566+5830. We found a single methanol feature at -45.7 km s^-1. The CO(1-0) emission was detected at -50.5 km s^-1(Wouterloot & Brand 1989). The CS(2-1) line at nearly the same velocity of -50.3 km s^-1 was reported by Bronfman et al. (1996). Wouterloot et al. (1993) found the H₂O maser emission in the velocity range from -67 to -40 km s^-1.
23139+5939. The 6.7 GHz methanol line was detected in the velocity range from -42 to -37 km s^-1. Bronfman et al. (1996) found the CS(2-1) line at -44.7 km s^-1. Wouterloot et al. (1993) found the H₂O maser emission in the velocity range from -57 to -31 km s^-1.

4.2 Known detections

Most of early observations of the 6.7 GHz methanol masers were carried out at different epochs in 1991 and 1992 (Menten 1991; MacLeod & Gaylard 1992; Gaylard & MacLeod 1993; Schutte et al. 1993; Caswell et al. 1995; van der Walt et al. 1995). Subsequent surveys were made in 1993-1994 (Lyder & Galt 1997; Walsh et al. 1997) and in 1995 (Slysh et al. 1999). Therefore, a comparison of those observations with our own data can provide some information on the variability of methanol masers on time-scales of 4 and 7-8 years.
00338+6312. MacLeod et al. (1998) first reported the methanol emission. They found a double-peaked spectrum with the main feature of 8.1 Jy at velocity -22.7 km s^-1. Slysh et al. (1999) reported the peak flux value of 10 Jy, but our value is 14 Jy. This suggests that the source is variable.
00494+5617. The 6.7 GHz maser was first reported by Slysh et al. (1999). Their peak flux density of a feature at -29 km s^-1 was 12 Jy, whereas our peak value is 24 Jy. We found a new feature at -36 km s^-1. This suggests that the source is strongly variable.
02455+6034. The methanol maser with a double peaked spectrum was discovered by Lyder & Galt (1997). Our data indicate that the feature at -45 km s^-1 decreased from 35 to 21 Jy, whereas that at -42 km s^-1 disappeared after $\sim$ 4.5 years, suggesting that the source is strongly variable. This source was also observed by Slysh et al. (1999), who listed in their Table 1, a 24 Jy peak flux density for -45.3 km s^-1 feature, but a lower value of 17 Jy is shown in their Fig. 1.
05274+3345. Our methanol spectrum of this source is only slightly different from that reported by Gaylard & MacLeod (1993). Comparison with data published by Slysh et al. (1999) suggests that at least the main feature at 4 km s^-1 exhibits a strong variation.
05358+3543. Menten (1991) found the 6.7 GHz emission at the position of S231 that is $51^{\prime \prime}$ away from the IRAS position. Our spectrum consists of 3 strong narrow features (0.10 - 0.14 km s^-1 full width to half power (FWHP)). A weaker emission is present over the velocity interval of $\sim$ 5 km s^-1, similar to that reported by Menten (1991). He obtained the peak flux density of 208 Jy, whereas our value is 256 Jy, indicating that the source is variable.
05480+2545. We found two emission complexes in the same velocity range as reported by Slysh et al. (1999). However, their data on this source are uncertain as the peak flux density given in their Table 1 is obviously different from that shown in their Fig. 1.
06053-0622. Our peak flux density of 166 Jy is virtually the same as that reported by Menten (1991). Caswell et al. (1995) published the methanol spectrum that is completely different from ours. This suggests that the source is strongly variable.
06055+2039. The methanol feature at velocity 5.5 km s^-1 appears to be non-variable as compared to the data published by Menten (1991) and Caswell et al. (1995). However, the intensity of the feature at 4 km s^-1 measured by Caswell et al. (1995) was about twice as large as our value of 17 Jy. No methanol emission was found by Walsh et al. (1997) with a sensitivity limit of 5 Jy. It appears that at least 4 km s^-1 feature is strongly variable.
06056+2131. We detected the methanol spectrum composed of two narrow features (0.12 km s^-1 FWHP) similar to those reported by Caswell et al. (1995). The maser feature at 11 km s^-1 is a sidelobe response to 06058+2138 (Caswell et al. 1995; Slysh et al. 1999).
06058+2138. The intensity and shape of the methanol spectrum observed in our survey are almost unchanged as compared to the observations by Menten (1991) and Caswell et al. (1995).
06099+1800. The same comment as for 06058+2138.
06117+1350. Menten (1991) found a methanol feature at 15 km s^-1about twice as strong as in our and in Caswell's et al. (1995) spectra. The source may be variable.
07299-1651. MacLeod & Gaylard (1992) reported a 42 Jy peak flux density of methanol emission, whereas Caswell's et al. (1995) value was 162 Jy. Walsh et al. (1997) observed the strongest feature of 180 Jy, but our value is 217 Jy. Evidently, the intensity is variable while the shape of the spectrum is almost unchanged since its discovery.
18056-1952. This source is $29^{\prime \prime}$ and $22^{\prime \prime}$ away from W31(1) (Menten 1991) and 10.47+0.03 (Caswell et al. 1995), respectively. Menten's observations gave the peak flux density of 823 Jy. Our methanol spectrum has a similar shape to that observed by Caswell et al. (1995), with an exception of the feature at 75 km s^-1 which intensity decreased from 61 Jy to 17 Jy. The methanol spectrum is strongly confused by the emission of the nearby sources 10.45-0.02 and 10.48+0.03 (Caswell et al. 1995).
18056-1954. Caswell et al. (1995) obtained a similar methanol spectrum at the position of 10.45-0.02 that is $1\hbox{$.\mkern-4mu^\prime$ }5$ away from the IRAS position, but the intensity was about twice as large as ours. The spectrum is strongly confused by the emission from 10.47+0.03 and 10.48+0.03 (Caswell et al. 1995).
18067-1927. A single methanol feature of 20 Jy at 24 km s^-1 was discovered by Schutte et al. (1993). Its intensity of 18 Jy was reported by Walsh et al. (1997), while our value is 15 Jy. These differences may be due to variability but an effect of calibration uncertainties cannot be excluded.
18089-1732. Menten (1991) first discovered this methanol source. The spectrum published by Caswell et al. (1995) is quite similar to that obtained in our survey, but some individual features are considerably variable.
18090-1832. Within the calibration uncertainties the peak intensity of the methanol maser measured in our survey is the same as reported elsewhere (Menten 1991; Caswell et al. 1995).
18092-1842. The general shape of the methanol spectrum taken in our survey is similar to that reported by Caswell et al. (1995). When comparing our data with those published by Menten (1991) and Caswell et al. (1995), we note a gradual decrease of maser intensity.
18094-1840. A weak methanol emission detected in the velocity range from 45 to 49 km s^-1 comes from this source (Caswell et al. 1995). At velocities lower than 45 km s^-1 our spectrum is contaminated by the emission from 18092-1842.
18097-1825. We found the methanol emission in the same velocity range as observed by Menten (1991). Our spectrum taken with a larger beamwidth is strongly confused by emission from two nearby sources 12.20-0.11 and 12.20-0.12 (Caswell et al. 1995).
18099-1841. The main methanol feature at 60.2 km s^-1 detected in our survey has the same intensity as reported by Walsh et al. (1997).
18102-1800. We detected at least 6 narrow methanol features (<0.20 km s^-1 FWHP). The emission in the velocity interval 52 to 59 km s^-1, also reported by Slysh et al. (1999), comes from 18108-1759.
18108-1759. This methanol source is $3\hbox{$.\mkern-4mu^\prime$ }8$ away from W33B discovered by Menten (1991) and $3\hbox{$.\mkern-4mu^\prime$ }4$ away from 12.68-0.18 published by Caswell et al. (1995). In consequence, our peak flux density is lowered by a factor of about two.
18110-1854. Our methanol spectrum is similar to that published by Caswell et al. (1995). Within the measurement errors our peak value is the same as reported by Menten (1991).
18117-1753. The peak flux densities of methanol maser measured by Menten (1991) and Caswell et al. (1995) were 327 and 317 Jy respectively, but our value of 242 Jy is considerably lower. This suggests that the source is variable.
18128-1640. Our methanol spectrum is similar to that discovered by Slysh et al. (1999), but the intensity of the feature at 15.3 km s^-1 decreased from 200 Jy to 135 Jy. This suggests that at least this main feature is variable.
18134-1942. The methanol maser was found by Schutte et al. (1993), who reported the peak flux of 248 Jy. Walsh et al. (1997) reported the peak value of 160 Jy, while our value is 116 Jy. Furthermore, the intensities of individual features in our spectrum differ significantly from those published by Schutte et al. (1993). This source is strongly variable.
18141-1615. This methanol source was undetected by van der Walt et al. (1995) with a sensitivity limit of about 5 Jy. Walsh et al. (1997) found a weak (2.3 Jy) emission in the velocity range from 19 to 35 km s^-1. We detected the methanol emission of similar intensity.
18144-1723. MacLeod et al. (1998) detected the methanol emission in the velocity interval 48 to 53 km s^-1 with the peak flux density of 24 Jy. Our peak value of 33 Jy is higher, possibly due to a higher spectral resolution.
18151-1208. A single methanol feature of 46 Jy at 27.8 km s^-1was discovered by van der Walt et al. (1995). Slysh et al. (1999) reported the peak flux density of 72 Jy. Within the measurement accuracy our data give the same peak flux density, but the spectrum has three features. The source is likely variable.
18174-1612. We observed the main methanol feature of 19 Jy at velocity 20.9 km s^-1. Menten (1991) obtained the peak flux density of 49 Jy, while Caswell's et al. (1995) value was 39 Jy. This suggests that the maser intensity decreased. The shape of our spectrum is similar to that published by Caswell et al. (1995).
18182-1433. We detected a methanol feature with the peak flux density of 24 Jy similar to that reported elsewhere (Menten 1991; Caswell et al. 1995). However, we note significant differences in the relative intensities of individual features when comparing our spectrum with that published by Caswell et al. (1995).
18196-1331. The methanol feature of 20 Jy at 20.5 km s^-1 detected in our survey has approximately the same intensity as that reported by MacLeod & Gaylard (1992) and Caswell et al. (1995). This suggests that the source is not variable.
18217-1252. Menten (1991) detected the methanol emission with the peak flux density of 28 Jy. During observations by Caswell et al. (1995) this peak was 23 Jy. Our value of 14 Jy suggests that the emission has decreased gradually over about 8 years' period.
18232-1154. This methanol source is offset by $1\hbox{$.\mkern-4mu^\prime$ }7$ to the position observed by Menten (1991), who found the methanol emission with the peak flux density of 24 Jy. Caswell et al. (1995) found two sources 19.47+0.17 and 19.48+0.15 with spectra contaminated by the emission from other nearby sources. Our spectrum is similar to that of 19.48+0.15.
18236-1241. The methanol emission discovered by Slysh et al. (1999) had a single feature with the peak flux density of 5 Jy. Our spectrum contains at least two narrow features of flux density of 2.3 Jy.
18236-1205. Walsh et al. (1997) found the methanol emission in the velocity range 24 to 31 km s^-1 with the peak flux density of 26 Jy. We obtained quite different spectrum with the peak flux density of 6.7 Jy. This allows us to conclude that the source is strongly variable.
18244-1155. Comparing our methanol data with those published by Caswell et al. (1995) we note a decrease of intensity by a factor of about two.
18249-1116. Menten first detected this methanol source with the peak flux density of 112 Jy. Our spectrum with the peak flux of 94 Jy is similar to that published by Caswell et al. (1995) where the peak flux density was 100 Jy. The source exhibits only a weak variation of intensity, if any.
18265-1517. This methanol source was first detected by Walsh et al. (1997). Our measurements indicate that within the uncertainty of about 15% the methanol emission is unchanged.
18282-0951. The peak flux density ( 15 Jy) of methanol emission previously reported (Menten 1991; Caswell et al. 1995) was about a factor of 5 higher than that measured in our survey. This suggests that the source is variable.
18290-0924. The methanol emission had the peak flux density of 21 Jy during discovery observations (Schutte et al. 1993). Our value of 12 Jy is the same as reported by Walsh et al. (1997). This source may be variable.
18310-0825. Our data indicate that this source has the methanol maser with the peak flux density of 12 Jy that is nearly the same as reported by Schutte et al. (1993). However, data presented by Walsh et al. (1997) and Slysh et al. (1999) suggest that the source is strongly variable.
18316-0602. A prominent methanol feature at 42 km s^-1 has the same intensity as published by Slysh et al. (1999). Previous observations gave its value of a factor of two lower (van der Walt et al. 1995; Walsh et al. 1997). We detected a broad emission from 38 to 44 km s^-1 about twice as strong as that observed by Walsh et al. (1997).
18317-0845. Schutte et al. (1993) first detected the methanol emission with the peak flux of 12 Jy. Other observations indicate a significant decrease of intensity by a factor of two (Walsh et al. 1997; Slysh et al. 1999). Our data give the peak flux density of 4.4 Jy and confirm a gradual decrease of intensity.
18319-0834. We detected the methanol emission in the velocity range from 95 to 108 km s^-1, similar to that reported by Menten (1991). Our spectrum is quite different from that published by Caswell et al. (1995). A mean level of maser emission in the velocity range 95-100 km s^-1 measured in our survey was comparable to that observed by Caswell et al. (1995), but emission at 101-108 km s^-1 decreased about twice.
18324-0737. The methanol emission with the peak flux density of 3 Jy was first detected by Menten (1991). Observations by Caswell et al. (1995) provided the peak flux of about 11 Jy. In our survey the shape of the spectrum was generally similar to that published by Caswell et al. (1995), but the peak flux density decreased to 4.6 Jy. This suggests that the source is variable.
18324-0820. Schutte et al. (1993) first found the methanol emission in the velocity range 75 to 81 km s^-1 with the peak flux density of 28 Jy. In the same velocity range a similar peak flux was reported by Slysh et al. (1999), but individual features appeared to be variable. Walsh et al. (1997) observed the maser emission in the velocity range 58 to 81 km s^-1 with the peak flux density of 26 Jy. The present observations revealed the emission in the velocity range 75 to 85 km s^-1 with the peak flux density of 9.2 Jy. We conclude that the source is strongly variable.
18334-0733. The methanol emission of 33 Jy at 114.5 km s^-1was first detected by van der Walt et al. (1995). Slysh et al. (1999) found the peak flux of 42 Jy at similar velocity. Our peak value of 29 Jy is nearly the same as measured by van der Walt et al. (1995). We detected two weak features at 111 and 113 km s^-1 not seen in other observations. The source appears to be variable.
18335-0713. The source was first detected at 6.7 GHz by Menten (1991), who reported the peak flux density of 89 Jy. A similar value of 82 Jy was published by Caswell et al. (1995). We note that their spectrum is very similar to ours, with the peak flux density of 97 Jy.
18341-0727. We detected the methanol line at the same velocity as Slysh et al. (1999). Our peak flux of 3.5 Jy is a factor of 4.5 lower than their value. This suggests that the maser is variable.
18345-0641. van der Walt et al. (1995) found the methanol emission in the velocity range from 94 to 100 km s^-1. Our observations indicate that their main peak of $\sim$ 45 Jy at $\sim$ 99 km s^-1 decreased to about 2 Jy, while a low intensity emission in the velocity range 94 to 98 km s^-1 is now dominated by two well-separated features. We conclude that the source is strongly variable.
18353-0628. The shape of the methanol spectrum taken in our survey is generally the same as observed by Walsh et al. (1997). However, the main feature at 96 km s^-1 increased from 225 Jy (Walsh et al. 1997) to 364 Jy at the time of our observations. This suggests that the source is variable.
18361-0627. Schutte et al. (1993) first detected the methanol emission from this source. They listed the peak flux density of 54.1 Jy, whereas their Fig. 2 indicates a value of $\sim$ 80 Jy. The intensity of the main feature at 92 km s^-1 obtained by Walsh et al. (1997) was 7.4 Jy, while our value is 20 Jy. This suggests that the source is strongly variable.
18379-0500. This methanol source was first discovered by Slysh et al. (1999). In their Table 1 they listed the peak flux density of 41 Jy, but their Fig. 1 indicates a value of $\sim$ 27 Jy at velocity 35 km s^-1. We found a 21 Jy feature at the same velocity.
18379-0546. van der Walt et al. (1995) found a single methanol feature of 10 Jy at about 104 km s^-1. Slysh et al. (1999) found a similar intensity of this feature and detected another feature at 115 km s^-1. Our data indicate that the latter feature has the same intensity as reported by Slysh et al. (1999), whereas the intensity of the feature at 104 km s^-1 increased by a factor of two. The source is likely variable.
18403-0417. Towards this source a weak ( $\sim$ 3 Jy) methanol emission was detected in the velocity range 94 to 102 km s^-1 (Menten 1991; Caswell et al. 1995; Walsh et al. 1997). With our beamwidth the spectrum is contaminated by the emission from the nearby source 28.15+0.00 (Caswell et al. 1995), which is $4\hbox{$.\mkern-4mu^\prime$ }6$ away from the IRAS position, nevertheless, our peak flux density is about twice larger than that reported by Caswell et al. (1995).
18416-0420. The methanol maser was first found by Schutte et al. (1993). Their spectrum had a single asymmetric feature at 81 km s^-1with the peak flux density of 59 Jy. Observations by Walsh et al. (1997) gave the peak value of 62 Jy, exactly the same as ours. The peak flux density of 75 Jy measured by Slysh et al. (1999) differs by about 18% from all previous values. This suggests that the methanol emission does not change at all. Our observations revealed that there are several weak features in the velocity ranges of 79-83 and 91-93 km s^-1.
18421-0348. The source was first detected at the 6.7 GHz maser line by Menten (1991), who reported the peak flux density of 85 Jy. Caswell et al. (1995) found a peak flux density of 73 Jy, while our value is 58 Jy. A comparison of our spectrum with Caswell's et al. spectrum indicates that individual features are variable.
18434-0242. The methanol spectrum obtained in our survey does not differ from that observed earlier (Menten 1991; Caswell et al. 1995). Emission at velocities higher than 102 km s^-1 comes from two nearby sources (Caswell et al. 1995).
18440-0148. Menten (1991) first detected the methanol emission with the peak flux density of 4 Jy. Data published by Caswell et al. (1995) indicate that the main feature at 105 km s^-1 decreased from 8 Jy to 3 Jy at the epoch of our measurements.
18441-0153. We detected the methanol emission in the velocity ranges of 47-49 and 70-89 km s^-1 with the peak flux densities of 19 and 8 Jy respectively. With a smaller antenna beam, Caswell et al. (1995) found two separate sources 30.78+0.23 with the peak flux density of 24 Jy at 49 km s^-1 and 30.79+0.20 with the peak flux density of 23 Jy at 86 km s^-1. A comparison of our observations with Caswell's et al. data suggests that the first source does not vary at all, but the intensity of methanol emission from the second source decreased by about a factor of three.
18443-0231. Menten (1991) reported the methanol emission in the velocity range 100 to 115 km s^-1, exactly the same as we observed. Caswell et al. (1995) found two sources; 30.20-0.17 with the methanol emission of about 18.7 Jy at velocities lower than 111 km s^-1 and 30.22-0.18 at velocities greater than 111 km s^-1. Our peak value of the feature at 108 km s^-1 is the same as reported by Caswell et al. (1995), whereas the intensity of 113 km s^-1 feature is about twice lower.
18446-0209. The peak flux density of 5 Jy was reported by Menten (1991). The methanol spectrum published by Caswell et al. (1995) contains several weak features in the velocity range 36 to 49 km s^-1and the peak value of 7.5 Jy at velocity 42.4 km s^-1. We detected a 4.8 Jy feature at nearly the same velocity.
18447-0229. The maser emission from this source is uncertain. Caswell et al. (1995) found the emission in the velocity range 111 to 115 km s^-1 with the peak of 11.7 Jy at 113 km s^-1 at offset of $5\hbox{$.\mkern-4mu^\prime$ }3$ to the IRAS position. We found emission at similar velocity; it was about four times weaker than that reported by Caswell et al. (1995).
18448-0146. The methanol spectrum towards this source is nearly the same as that reported by Schutte et al. (1993) towards 18446-0150. Angular separation between both sources is $3^{\prime}$ . We observed 18446-0150 at the same epoch and obtained the intensity of the emission about three times lower than that measured from 18448-0146. Walsh et al. (1997) reported a 2.4 Jy methanol feature from 18446-0150. We conclude that the strongest methanol emission comes from 18448-0146.
18449-0158. We detected the methanol emission in the velocity range 87 to 93 km s^-1. $2\hbox{$.\mkern-4mu^\prime$ }1$ away from the IRAS position, a maser source with the peak flux density of 68 Jy at 92 km s^-1 was found (Caswell et al. 1995). The shape of the spectrum and the intensity measured in our survey are quite different from that published by Caswell et al.
18449-0115. The methanol emission from this source was first detected by Schutte et al. (1993). Our spectrum is quite similar to that published elsewhere (Schutte et al. 1993; Caswell et al. 1995). This suggests that the source is not variable.
18450-0205. The general shape of the methanol spectrum obtained in the survey is similar to that observed by Caswell et al. (1995), but the intensity decreased by a factor of two.
18450-0200. Our methanol spectrum is contaminated by the emission from 18450-0205. Only emission at velocities larger than 90 km s^-1 comes from the source. The peak flux density published by Caswell et al. (1995) is about twice higher than ours.
18452-0141. The methanol spectrum first published by Schutte et al. (1993) had two narrow features in the velocity range 15 to 17 km s^-1. Our spectrum is quite similar, but a redshifted feature decreased in intensity by a factor of two. Walsh et al. (1997) reported that this feature had the peak flux density of 3 Jy. This suggests that the source is variable.
18454-0156. The methanol emission was found by Menten (1991) and Caswell et al. (1995) $3\hbox{$.\mkern-4mu^\prime$ }9$ away from the IRAS position. Due to the offset position our peak flux density of 4.3 Jy differs significantly from values of 21 and 18 Jy reported in the papers above.
18456-0129. Menten (1991) found the methanol emission in the velocity range 104 to 114 km s^-1 with the peak flux density of 87 Jy. The general shape of the spectrum published by Caswell et al. (1995) is similar to ours, but the intensities of some individual features are different. The source is possibly variable.
18470-0050. Our methanol spectrum is very similar to that obtained towards 18470-0044 by van der Walt et al. (1995). However, in their Table 1 they listed this source as non-detection, whereas in their Table 2 the methanol line parameters are given for 18470-0049. We made the observations of all three sources at the same epoch. It appeared that the strongest emission comes from 18470-0050.
18487-0015. The methanol emission first found by Menten (1991) had the peak flux density of 46 Jy. A similar value of 47 Jy was reported by Caswell et al. (1995). Our measurements give the same peak flux density and the spectrum similar to that published by Caswell et al. (1995). However, we note a considerable decrease of intensity of the features at about 33 km s^-1.
18488+0000. The methanol maser from this source was discovered by van der Walt et al. (1995). Our observations give a spectrum of the same shape as that reported by van der Walt et al. (1995) and Slysh et al. (1999). The peak flux density of the main feature at 92 km s^-1 increased from 16 Jy (van der Walt et al. 1995) to 21 Jy (Slysh et al. 1999), whereas our peak value is 27 Jy. This suggests that the source is variable.
18494+0002. The methanol emission was found in the velocity range 95 to 106 km s^-1 (Caswell et al. 1995). We found the emission at the same velocities but intensities of individual features are quite different.
18496+0004. We found the maser emission with the peak flux density of 13 Jy. Similar values of 10 and 12 Jy were reported by Menten (1991) and Caswell et al. (1995) respectively. We also note that the shape of the spectrum is the same as published earlier. This source is likely to be non-variable.
18497+0022. The general shape of the methanol spectrum obtained here is similar to that reported by Slysh et al. (1999). Differences in intensities of individual features between Slysh's et al. observations and our data can result from our higher spectral resolution and sensitivity.
18507+0121. Schutte et al. (1993) detected the methanol emission at velocities of 55-64 km s^-1. Comparing their spectrum with ours, we see that the relative intensities of two prominent features significantly changed.
18507+0110. Menten (1991) discovered the methanol emission with the peak flux density of 32 Jy. Observations by Caswell et al. (1995) provided the peak value of 29 Jy, while we obtained a lower value of 18 Jy. This suggests that the source is variable. Caswell's et al. data indicated that emission at 56 km s^-1 comes from a nearby source.
18515+0157. We found the methanol emission in the velocity range 44 to 47 km s^-1, which is similar to that reported by Menten (1991). Our peak flux density is 35 Jy, which is significantly lower than 50 Jy and 56 Jy, measured by Menten (1991) and Caswell et al. (1995) respectively, suggesting that this source is variable.
18517+0437. Schutte et al. (1993) found the methanol emission with the peak flux density of 298 Jy at velocity 41 km s^-1. We obtained nearly the same value of 279 Jy. The present observations revealed a weak ( $\sim$ 7 Jy) emission near 45-46 and 51 km s^-1.
18556+0136. Menten (1991) first detected the methanol emission in the velocity range 27 to 34 km s^-1 with the peak flux density of 107 Jy. The methanol spectrum published by Caswell et al. (1995) is quite different from that obtained here. This suggests that the source is variable.
18566+0408. Slysh et al. (1999) first found the methanol maser in this source. Their spectrum is similar to ours, obtained with higher spectral resolution and sensitivity.
18572+0057. van der Walt et al. (1995) detected the methanol emission with the peak flux density of 21 Jy. Our data indicate that the spectrum is composed of several narrow features of intensities comparable to those reported by Slysh et al. (1999). This source may be weakly variable.
18592+0108. This source was detected in the 6.7 GHz methanol line by Menten (1991), who found the peak flux density of 556 Jy. The same value was found by Caswell et al. (1995). Our peak flux density is 595 Jy. This suggests that the main feature does not vary. However, other features show considerable changes.
19002+0654. The methanol maser was discovered by Schutte et al. (1993). They found two features in the velocity interval of 13-17 km s^-1. Our observations revealed much broader velocity range of 5-16 km s^-1, where several weak features are seen.
19035+0641. Menten (1991) discovered the methanol maser in the velocity range 30 to 37 km s^-1 with the peak flux density of 14 Jy. Caswell et al. (1995) reported a similar peak value of 17 Jy. We found the emission in the same velocity interval with the peak flux density of 15 Jy. This source is non-variable.
19078+0901. We obtained a very similar methanol spectrum as that discovered by Menten (1991). His peak flux density of 28 Jy is close to our value of 31 Jy. Caswell et al. (1995) found a cluster of three sources with methanol emission in the velocity range 6 to 22 km s^-1. A comparison of our data with those quoted above suggests that the source is non-variable.
19092+0841. MacLeod et al. (1998) discovered the methanol emission with the peak flux density of 11.6 Jy at 55 km s^-1. We obtained a similar spectrum with the peak value of 10 Jy, which suggests that the source is non-variable.
19095+0930. Menten (1991) discovered the methanol emission in the velocity range 30 to 44 km s^-1 with the peak flux density of 152 Jy. In the same velocity interval, Caswell et al. (1995) found the peak flux density of 144 Jy. The present survey indicates that the emission at velocity 40 km s^-1 decreased by a factor of two, but that at velocity 43 km s^-1 has the same intensity as reported by Caswell et al. (1995).
19110+1045. The methanol emission discovered by Menten (1991) had the peak flux density of 42 Jy. Observations by Caswell et al. (1995) revealed a decrease of the peak value to 33 Jy. Our data give the peak value of 45 Jy, which is very similar to that reported by Menten (1991). This suggests that the emission from this source is variable.
19117+1107. We found the methanol emission in the velocity range 57 to 67 km s^-1 which is similar to that reported by Menten (1991). Our peak flux density of 10 Jy is by a factor of 1.5 lower than that listed by Menten (1991). The data published by Caswell et al. (1995) indicated that the emission at about 57 km s^-1 comes from 45.47+0.05, which is located $45^{\prime \prime}$ away from IRAS source 19120+1103.
19120+1103. The methanol emission from this source was first discovered by Menten (1991). Our data confirm that the emission at velocities larger than 59 km s^-1 is confused by the source 19117+1107, named 45.47+0.13 by Caswell et al. (1995).
19120+0917. Schutte et al. (1993) first detected the methanol maser. They found a spectrum with two features at 48 and 52 km s^-1 and flux densities of about 10 Jy. Our observations revealed a quite different spectrum with the peak value of 34 Jy at about 48 km s^-1. This suggests that the source is strongly variable.
19216+1429. The methanol emission detected towards this source is likely to be a sidelobe response to W51 (Menten 1991; Caswell et al. 1995) that is $6\hbox{$.\mkern-4mu^\prime$ }8$ away from 19216+1429.
19230+1341. van der Walt et al. (1995) first detected the methanol maser towards this source. Although their peak value of 24 Jy does not differ significantly from ours, we note very large changes in the spectrum shape.
19410+2336. This source was discovered by Menten (1991), who found the methanol emission in the velocity range 15 to 28 km s^-1with the peak flux density of 103 Jy. Caswell's et al. (1995) observations revealed the peak flux density of 42 Jy at 25 km s^-1, whereas our data show the strongest feature of 34 Jy at 17.3 km s^-1 and the spectrum is completely different. This suggests that the source is strongly variable.
19589+3320. The methanol emission with the peak flux density of 22 Jy at velocity -26 km s^-1 was first detected by Slysh et al. (1999). We found the main feature of flux density of 9.8 Jy at the same velocity. This source can be variable.
20062+3550. Slysh et al. (1999) discovered the methanol maser with a single peak of flux density of 32 Jy at velocity -3 km s^-1. Our data indicate that the intensity of this feature decreased to 10 Jy and a new feature appeared at 6 km s^-1. This suggests that the source is variable.
20081+3122. The methanol emission with the peak flux density of 91 Jy was first detected by Menten (1991). Our peak value is 109 Jy, suggesting weak variations of this source, if any.
20126+4104. The methanol maser was first reported by MacLeod & Gaylard (1992) and their peak flux density was 7 Jy. Slysh et al. (1999) published the methanol spectrum with two prominent features with the peak flux density of 61 Jy. Our survey revealed a single asymmetric feature of the flux density of 38 Jy. This suggests that the source is strongly variable.
20198+3716. This source was discovered in the 6.7 GHz line by Menten (1991). His peak flux density of 54 Jy is higher than ours (39 Jy). This is possibly due to variability.
20350+4126. Slysh et al. (1999) first reported the methanol maser from this source. They found a feature of 10 Jy at velocity -4 km s^-1. We found a 4 Jy feature at the same velocity. This suggests that the maser emission is variable.
21381+5000. Slysh et al. (1999) found the methanol emission in the velocity range from -45 to -39 km s^-1 with the peak flux density of 19 Jy. Our observations revealed quite different spectrum with the peak value of 7 Jy. This suggests that the source is strongly variable.
22272+6358. The methanol emission was first reported by Slysh et al. (1999), who found the peak flux density of 109 Jy at -11 km s^-1. Their spectrum is similar to ours, with the peak value of 91 Jy.
22543+6145. This is one of the strongest sources of the 6.7 GHz methanol emission discovered by Menten (1991). He reported the peak value of 1420 Jy, while our value is 815 Jy. This indicates that the intensity of the main feature at -2.5 km s^-1 decreased, whereas the intensities of other features do not show notable variations.
23116+6111. Menten (1991) found the methanol emission in the velocity range from -62 to -54 km s^-1 with the peak flux density of 346 Jy. Our peak value of the main feature at -56.3 km s^-1 is 296 Jy. We found a weak ( $\sim$ 4-9 Jy) emission at velocities -53 and -49 km s^-1. Individual features at velocities lower than -55 km s^-1 appear to be variable.

4.3 non-detections

02219+6152. The 6.7 GHz methanol emission from this source was reported by Slysh et al. (1999). With our beamwidth we also detected a weak ( $\sim$ 7 Jy) emission in the velocity range from -46 to -42 km s^-1. The spectrum shape and the velocity range of this emission are very similar to those observed towards 02232+6138 (W3(OH)). This emission appears to be a sidelobe response to W3(OH).
18021-1950. The methanol emission of 0.4 Jy reported by Walsh et al. (1997) lies below our sensitivity limit.
18067-1921. A weak (0.7 Jy) methanol emission at velocity 20 km s^-1 detected by Walsh et al. (1997) lies below our 3 $\sigma$ upper limit. A single feature observed at 24 km s^-1 is a sidelobe response to 18067-1927.
18248-1158. Caswell et al. (1995) found a weak (0.4 Jy) methanol emission that lies below our 3 $\sigma$ detection limit.
18335-0711. The methanol maser was reported by Caswell et al. (1995). With our beamwidth this source is badly contaminated by 18335-0713.
18443-0210. The methanol emission with the peak flux density of 0.6 Jy was reported by Walsh et al. (1997), but lies below our 3 $\sigma$ detection limit.
18470-0044. Slysh et al. (1999) reported the methanol emission towards this source. We observed several nearby IRAS sources and found that the strongest emission comes from 18470-0050.
19220+1432. Slysh et al. (1999) found the methanol emission with the peak flux density of 10 Jy at velocity 60 km s^-1. We did not find any emission above 3 $\sigma$ upper limit of 1.8 Jy. This suggests that the source is strongly variable.
19388+2357. Schutte et al. (1993) observed a 24.7 Jy methanol feature at velocity 38 km s^-1. The peak value measured by Slysh et al. (1999) was 31 Jy. No emission was found in our survey with 3 $\sigma$ upper limit of 1.5 Jy. This suggests that the source is strongly variable.
22551+6139. MacLeod et al. (1998) and Slysh et al. (1999) reported the 6.7 GHz methanol emission. We detected the methanol emission towards this source but its velocity range and the peak ratio of two features are exactly the same as measured for 22543+6145. We conclude that this emission is a sidelobe response to 22543+6145.

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