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tokens: and low column densities, which appear to support that the hot core is externally heated. The strong bursting observed in the water masers located in the direction of the HMC in Orion-KL could be caused by the interaction between the explosive outflow and the ambient quiescent gas (Hirota et al. 2011 , 2014 ). In this study, using the tremendous sensitivities, a better uv-plane coverage, and a very broad covering of frequency range at (sub)millimeter wavelengths offered by the recent operational Atacama Large Millimeter/Submillimeter Array observatory (ALMA), we carried out a search for compact and faint continuum sources (in five different continuum bands of ALMA) that are probably associated with (proto)stellar objects and hot molecular gas within the HMC in Orion-KL. We report, in addition to Orion Source I and Orion BN, the detection at submillimeter wavelengths of three new compact continuum sources (ALMA1-3) that are located in the vicinities of the HMC, but not with associated hot molecular gas. Additionally, one of these compact sources seem to be associated with high-mass stars, but it does not account for the internal heating of the HMC. We thus conclude that the hot molecular core in Orion-KL is indeed heated externally, as suggested by many observational works. 2. Observations The observations were carried out with ALMA between 2014 and 2015 as part of the ALMA programs: 2013.1.01034.S (Band 4), 2012.1.00146.S (Band 6), 2013.1.00048.S (Band 8), and 2012.1.00123.S (Bands 7 and 9). The total bandwidth used to estimate the continuum emission in the ALMA observations was more than 2 GHz (see Table 1 ). However, as there are many lines detected in the spectral windows, and there is probably some contamination from very faint lines. In order to search for compact millimeter sources within the hot molecular core in Orion-KL, we constrain the uv-range of the observations (see Table 1 and Figures 1 – 3 ). We chose the uv-range based on a trade-off between removing as much extended emission as possible and keeping enough visibilities to obtain a good map. The resulting synthesized beams are presented in Table 1 . The number of antennas used during the observations varied between 31 and 40 (see Table 1 ). Weather conditions were very good and stable, with an average precipitable water vapor of 6 mm (Band 3), 1 mm (Band 6), 0.3–0.7 mm (Band 7), 0.3 mm (Band 8), and 0.15 mm (Band 9). Figure 1. ALMA continuum band 4 (3.0 mm) contour and color-scale images of the HMC located in Orion-KL. Upper panel: continuum image using the full uv-range from the ALMA observations. The contours start at 15% and go up to 90% in steps of 5% of the intensity peak. The intensity peak is 0.150 Jy Beam −1 . The half-power contour of the synthesized beam of the image is shown in the bottom-left corner. Lower panel: continuum image using only part of the uv-range (>150 kλ ) from the continuum observations. The contours start at 15% and go up to 90% in steps of 5% of