ALMAGAL Continuum Emission
The continuum emission at 1.3 mm of the 1013 clumps observed by the ALMAGAL survey revealed the complexity and the different morphologies that can characterize different high-mass star-forming regions. Some clumps show relatively extended emission that is mostly resolved at the 1000 au scale, in some fields the emission is distinctively filamentary, while in others can be extended with an irregular shape. On the contrary, other fields show little extended emission, with only compact sources. In this page we gave access to images preview of the ALMAGAL continuum emission for each source, together with the results of the analysis performed on this dataset.
Compact sources catalog
Coletta et al. 2025 (download here) analyzed the continuum emission of the ALMAGAL targets at a resolution of ~1000 au to extract the catalog of the compact sources. The analysis has been performed using the algorithm CuTEx, which identifies compact sources as maxima of curvature in maps by analyzing their second derivatives. This method allows an easier identification of compact sources, which stand out in the curvature images, while diffuse and background emission is strongly dampened.
The ALMAGAL compact sources catalog (available from CDS) includes 6348 cores detected in 844 clumps (83% of the total), with a number of cores per clump between 1 and 49 (median of 5). The estimated core diameters are mostly within ~800–3000 au (median of 1700 au). We assigned core temperatures based on the L/M of the hosting clump, and obtained core masses from 0.002 to 345 M⊙ (complete above 0.23 M⊙), exhibiting a good correlation with the core radii (M∝R2.6).
A preview of the continuum emission at 1000 au resolution for each ALMAGAL target, together with the results of the cores extraction on the target can be access at the link below. For each source, we report in green the ellipses that identify the compact cores, and we report in the top left corner the total number of cores detected. On the bottom of each image we give some of the properties of the source at clump level.
Spatial distribution of compact cores
Schisano et al. 2025 (download here) analyzed the spatial distribution of the compact cores identified in ALMAGAL fields at scales of ~1000 au. The emission in each field has been characterized using several approach and indicators for targets with more than 4 compact cores identified, which corresponds to a total of 514 sources. That can be visualized in the images shown in the page linked below. We report also the images for sources with less than 4 cores (not included in the analysis of the paper), for which only a subset of analysis and indicators is present.
Each figure shows the continuum emission at 1.3 mm of the ALMAGAL targets obtained by combining data from the 12m (compact and extended configurations) and 7m arrays. The positions of the ALMAGAL cores in the field are indicated with gray star symbols. The black contours correspond to intensity levels of 4σ, with σ equal to the noise measured in each map. Thick solid black lines show the minimum spanning tree (MST) edges connecting the cores detected in the field, which trace their spatial distribution. The cluster geometrical center and the cluster radius, Rcl, are indicated with a black cross and a dark blue circle, respectively. Lastly, the cyan lines show the convex hull (CH) polygon derived from the distribution of cores, while the black dashed line corresponds to the best-fit ellipse to the CH.
The quantities reported in each figure are: Rcl is the cluster radius, defined as the distance of the farthest core from the cluster geometrical center. ξ is the cluster elongation, computed as the ratio between Rcl and the equivalent radius of the convex hull polygon according to the definition of Schmeia & Klessen (2006). e is the elongation, computed as the axis ratio of the ellipse best fitting the CH polygon. MthJ and λthJ are the thermal Jeans mass and length, computed from the clump-averaged properties. lmed is the median of the distribution of projected separations. lmod is the mode of the continuous distribution P(l), derived by applying a Gaussian Kernel Density Estimate to the measured projected separations. Δl is the width of P(l), defined at 68% of the peak intensity of the continuous distribution. Ncores is the number of detected cores in the clump from Coletta et al. (2025). Q-par is the value of the Q-parameter computed for the spatial distribution of the ALMAGAL cores.
