Figure 1 presents the Stokes I image from W43-MM1. The continuum emission shows a fragmented filament extending from the north to the south–west. Two bright sources at the center, A and B1, completely dominate the energy budget in W43-MM1 (with integrated fluxes of ∼2.0 and 0.5 Jy, which correspond to 





 of the total flux recovered), over a number of additional fragments extending to the south–west. Also, additional sources to the east and west have been detected. Comparing with the SMA results from Sridharan et al. (2014) and the PdBI 1 mm results from Louvet et al. (2014), the ALMA observations reproduce quite well the overall morphology of W43-MM1, but with better resolution. The noise in the ALMA map is 





 with a peak of 503 mJy 





 obtained from Gaussian fitting. We used the getsources algorithm (Men'shchikov et al. 2012) to successfully extract 14 sources from our ALMA data (see Table 1 and Figure 1). The extraction was later compared to other methods such as clumpfind (Williams et al. 1994), FellWalker, and Reinhold (Berry et al. 2007) obtaining a good agreement with the selection produced by getsources. We used the source positions and sizes derived using getsources as initial guess for a Gaussian 2D fitting (using CASA imfit algorithm) in order to derive accurate fluxes from the extracted sources.14

14
We found that getsources tends to underestimate the recovered fluxes from our data.
 Also, we kept the same source nomenclature used by Sridharan et al. (2014), but adding numbers where higher multiplicity was discovered with respect to the SMA map. Using the standard procedure to calculate masses from dust emission (Hildebrand 1983), we computed masses for all 15 sources in our catalog assuming a dust opacity of 





 cm2 g−1 (Ossenkopf & Henning 1994), a gas to dust ratio of 1:100, and a dust temperature of 





 K (Bally et al. 2010), with the exception of the hot core, source A, where we used a range between 





 K. Although the SMA detected CH3CN emission toward B1 and C, it was unresolved and not sufficient to derived temperatures; hence, we used 





 K for these sources. Herpin et al. (2012) modeled an spectral energy distribution and derived a temperature profile for source A using all the publicly available data on W43-MM1 to date. Their model suggests a temperature of ∼150 K at 2500 au distance (05 radial; 





 size) and ∼70 K at about 8000 au distance (07 radial; 14 size), which are the length scales sampled by ALMA. However, if larger spatial scales than our source size are considered, the temperature might be lower and on the order of 30 K (as suggested by Bally et al. 2010). These scales (





) are consistent with Herschel primary beam at 160 μm and, of course, larger than our deconvolved source sizes and synthesized beam. Therefore, and using this temperature range, our derived mass for source A is between 312 and 146 M





(with the exception of the 30 K temperature derived mass of 728 M





). These estimates put source A below other massive clumps such as the SDC335-MM1 mass estimate of 545 M





(Peretto et al. 2013) and G31.41+0.31 with a mass estimate of 577 M





 (Girart et al. 2009).15

15
Note that in this massive core a magnetic field strength of 10 mG was derived using n(H2) = 





 cm−3.
 However, these mass estimates were derived from observations sampling larger length scales than our ALMA W43 observations. The deconvolved size of SDC335-MM1 is about 0.054, which is two times the size of source A or four times the area. A simple estimate assuming an 





 density profile, will give about 272 M





 per source A size for SDC335-MM1 and about 205 M





 per source A size for G31.41+0.31.
Citation: Ossenkopf & Henning 1994
Citation function: Uses; Uses