Investigations of MWISP Clumps: 13CO Clump Source Catalog and Physical Properties

Abstract

We present the first comprehensive catalogs of $^{13}$CO clumps from the Milky Way Imaging Scroll Painting (MWISP) project. By developing an equivalent global detection scheme integrated with the FacetClumps algorithm, we successfully extract 71,661 molecular clumps across a high-resolution $^{13}$CO data cube spanning 2310 deg$^2$ from the MWISP Phase I survey. To determine accurate distances, we design an automatic hierarchical distance decision method using signal regions as fundamental objects, effectively resolving the kinematic distance ambiguity problem and obtaining reliable measurements for 97.94% of the sample. Statistical analysis reveals that 65.3% of clumps are gravitationally bound, accounting for approximately 96.3% of the statistical total mass. Scaling relation analysis across multiple surveys reveals universal power-law behaviors in clump populations. Maser-associated clumps exhibit modified parameter distributions and scaling relations, revealing how active star formation alters clump dynamics and structure. These extensive catalogs establish a foundation for investigating molecular clump properties, star formation processes, and Galactic evolution.

Figures (14)

• Figure 1: Schematic diagram illustrating the equivalent global detection scheme. (a) The SRs extracted from the original data (see Figure 1 of DPConCFil) by FacetClumps. Curves of different colors represent the boundaries of different SRs. (b) The reconstructed SR data cube, corresponding to the red contours in (a). The asterisks denote the centers of the clumps, and the direction of the red straight lines indicates the orientation of the clumps at the untouched edges. Contours in different colors represent the boundaries of the clumps. To avoid confusion, only a subset of the clump boundaries is shown. (c) The reconstructed SR data cube, corresponding to the blue contours in (a). (d) Detection results storage data cube. Transfer the detection masks from (b) and (c) to a storage data cube of the same size as the original data. The inset view shows two clumps in detail, and the black circle in the bottom-left corner marks the spatial resolution of MWISP.
• Figure 2: Distribution of all clumps in the Galactic longitude–latitude and Galactic longitude–velocity planes. Different colored dashed lines illustrate various spiral arms from the model by Distance_1, with their names labeled.
• Figure 3: Distribution of clumps across the Galactic longitude--latitude plane. Box plots illustrate the statistical distribution of Galactic latitude within discrete longitude intervals. Each box displays the interquartile range (IQR), with upper and lower boundaries marking the third and first quartiles, respectively, and the horizontal line indicating the median. The colored dashed-dotted lines represent median values for specific populations: red for positive Galactic latitudes (GLat $>$ 0), blue for negative latitudes (GLat $<$ 0), and black for the overall sample. Whiskers extend to the most extreme data points within 1.5 $\times$ IQR, revealing the dispersion across different Galactic longitudes. The orange line (right axis) quantifies the source count within each longitude bin.
• Figure 4: Flow chart showing the KDA solutions procedure adopted for the MWISP SRs in the FGQ.
• Figure 7: Distance comparison of paired ATLASGAL and MWISP clumps. Black crosses mark MWISP clumps whose distance classification is based on maser associations, while blue crosses mark MWISP clumps that utilize maser distance measurements. The density distribution of matched clumps is estimated via KDE, where the color scale represents the relative probability density of clump occurrences. The lime contour outlines the region where KDE values exceed 90% of the distribution. Within this contour, the lime dotted line represents the fitted linear relationship to the clump distance pairs, with a slope of $1.04\pm0.009$. The red dashed line represents the $y = x$ reference line.