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.
<Astron. Astrophys. 597, A114 (2017)>
=2017A&A...597A.114B 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°. 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:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 131 496 Reliable cluster candidates
table2.dat 72 1137 Potential cluster candidates
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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
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Bytes Format Units Label Explanations
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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)
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Note (1): Compute with Dpeak and R0=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 2014ApJS..212....1A, Cat. J/ApJS/212/1)
2 = Paladini et al. (2003A&A...397..213P 2003A&A...397..213P, Cat. J/A+A/397/213)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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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)
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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
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Acknowledgements:
Maxime Beuret, maxime.beuret(at)astro.unistra.fr
(End) Maxime Beuret [CDS, France], Patricia Vannier [CDS] 24-Nov-2016