J/A+A/597/A114 Hi-GAL cluster candidates physical properties (Beuret+, 2017) ================================================================================ Source clustering in the Hi-GAL survey determined using a minimum spanning tree method. Beuret M., Billot N., Cambresy L., Eden D.J., Elia D., Molinari S., Pezzuto S., Schisano E. =2017A&A...597A.114B (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Milky Way ; Interstellar medium ; Infrared sources ; H II regions Keywords: stars: formation - stars: luminosity function, mass function - Galaxy: structure - infrared: stars - catalogs Abstract: The aims are to investigate the clustering of the far-infrared sources from the Herschel infrared Galactic Plane Survey (Hi-GAL) in the Galactic longitude range of -71 to 67{deg}. These clumps, and their spatial distribution, are an imprint of the original conditions within a molecular cloud. This will produce a catalogue of over-densities. The minimum spanning tree (MST) method was used to identify the over-densities in two dimensions. The catalogue was further refined by folding in heliocentric distances, resulting in more reliable over-densities, which are cluster candidates. We found 1633 over-densities with more than ten members. Of these, 496 are defined as cluster candidates because of the reliability of the distances, with a further 1,137 potential cluster candidates. The spatial distributions of the cluster candidates are different in the first and fourth quadrants, with all clusters following the spiral structure of the Milky Way. The cluster candidates are fractal. The clump mass functions of the clustered and isolated are statistically indistinguishable from each other and are consistent with Kroupa's initial mass function. Description: Physical properties for 1633 Hi-GAL cluster candidates in the inner part of the Galactic Plane are presented. The 1633 cluster candidates are splitted into two tables : 496 reliable cluster candidates and 1137 potential cluster candidates. For each of the 1633 cluster candidates central positions, angular minor and major axis, position angles of the ellipses, the total number of clumps and the ratio of number of pre-stellar clumps over proto-stellar clumps are given. Besides these properties, for each reliable cluster candidates heliocentric distances, galactocentric distances, scale heights, linear minor and major axis, surface densities and closest HII regions are given. For each potential cluster candidates angular surface density and a flag that determines their classifications as potential cluster candidates are given. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 131 496 Reliable cluster candidates table2.dat 72 1137 Potential cluster candidates -------------------------------------------------------------------------------- See also: J/A+A/397/213 : Galactic HII regions (Paladini+, 2003) J/ApJS/212/1 : The WISE catalog of Galactic HII regions (Anderson+, 2014) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 12 A12 --- Name Cluster candidate name 15- 20 F6.2 deg GLON Galactic longitude 23- 27 F5.2 deg GLAT Galactic latitude 30- 34 F5.2 arcmin amaj Major axis 37- 41 F5.2 arcmin bmin Minor axis 44- 49 F6.2 deg PA Position angle 52- 56 F5.2 kpc Dpeak Heliocentric distance estimated from the peak of the heliocentric distance estimates histogram of the clumps 59- 63 F5.2 kpc Dmean Mean of the heliocentric distance estimates of the clumps 66- 70 F5.2 kpc Dgal Galactocentric distance (1) 73- 79 F7.2 pc Z Scale height (2) 82- 86 F5.2 pc Lamaj Linear major axis (2) 89- 93 F5.2 pc Lbmin Linear minor axis (2) 96- 99 F4.2 pc-2 Dens Surface density 102-104 I3 --- Nclumps Number of clumps 107-111 F5.2 --- Rclumps ?=- Ratio of the number of pre-stellar clumps over proto-stellar clumps 112 A1 --- n_Rclumps [ab] Note when no value (3) 114-128 A15 --- HII Closest HII region (4) 131 I1 --- Flag [1,2]? Catalog flag (5) -------------------------------------------------------------------------------- Note (1): Compute with Dpeak and R_0_=8.5kpc. Note (2): Compute with Dpeak. Note (3): Note as follows: a = no pre-stellar clumps b = no proto-stellar clumps Note (4): "Closest" means that at least one clump is located in the radius of the HII region. Note (5): HII regions belong to two catalogs as follows: 1 = Anderson et al. (2014ApJS..212....1A, Cat. J/ApJS/212/1) 2 = Paladini et al. (2003A&A...397..213P, Cat. J/A+A/397/213) -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 12 A12 --- Name Cluster candidate name 15- 20 F6.2 deg GLON Galactic longitude 23- 27 F5.2 deg GLAT Galactic latitude 30- 34 F5.2 arcmin amaj Major axis 37- 41 F5.2 arcmin bmin Minor axis 44- 49 F6.2 deg PA Position angle 52- 55 F4.2 arcmin-2 Dens Surface density 58- 60 I3 --- Nclumps Number of clumps 63- 67 F5.2 --- Rclumps ?=- Ratio of the number of pre-stellar clumps over proto-stellar clumps 68 A1 --- n_Rclumps [ab] Note when no value (1) 70- 72 A3 --- Flag [NDA, SD, SCC] Classification flag (2) -------------------------------------------------------------------------------- Note (1): Note as follows: a = no pre-stellar clumps b = no proto-stellar clumps Note (2): Classification of the potential cluster candidates as follows: NDA = No Distance Available, classifies sources without HDE SD = Spread Distance, cluster to which no particular distance can be assigned as there are only a few clumps with HDEs and these HDEs show some spread SCC = Satisfying Compactness Criteria, more reliable cluster candidates but with a confused line of sight -------------------------------------------------------------------------------- Acknowledgements: Maxime Beuret, maxime.beuret(at)astro.unistra.fr ================================================================================ (End) Maxime Beuret [CDS, France], Patricia Vannier [CDS] 24-Nov-2016