J/MNRAS/374/399 Infrared star clusters with |b|<20° (Froebrich+, 2007)
A systematic survey for infrared star clusters with |b|<20° using 2MASS.
Froebrich D., Scholz A., Raftery C.L.
<Mon. Not. R. Astron. Soc., 374, 399-408 (2007)>
=2007MNRAS.374..399F 2007MNRAS.374..399F
ADC_Keywords: Clusters, globular ; Clusters, open ; Infrared sources
Keywords: methods: statistical - globular clusters: general -
open clusters and associations: general
Abstract:
We used star density maps obtained from the Two-Micron All-Sky Survey
(2MASS) to obtain a sample of star clusters in the entire Galactic
Plane with |b|<20°. A total of 1788 star cluster candidates are
identified in this survey. Among those are 681 previously known open
clusters and 86 globular clusters. A statistical analysis indicates
that our sample of 1021 new cluster candidates has a contamination of
about 50 per cent. Star cluster parameters are obtained by fitting a
King profile to the star density. These parameters are used to
statistically identify probable new globular cluster candidates in our
sample. A detailed investigation of the projected distribution of star
clusters in the Galaxy demonstrates that they show a clear tendency to
cluster on spatial scales in the order of 12-25pc, a typical size for
molecular clouds.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 118 473 Properties of the probable clusters in our sample
of newly detected star cluster candidates
tableb1.dat 105 548 Properties of the possible clusters in our sample
of newly detected star cluster candidates
--------------------------------------------------------------------------------
See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
Byte-by-byte Description of file: tablea1.dat tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- FSR [1/1767] Sequential number,
<[FSR2007] NNNN> in Simbad
6- 12 F7.3 deg GLON Galactic longitude
14- 20 F7.3 deg GLAT Galactic latitude
22- 23 I2 h RAh Right ascension (J2000)
25- 26 I2 min RAm Right ascension (J2000)
28- 29 I2 s RAs Right ascension (J2000)
31 A1 --- DE- Declination sign (J2000)
32- 33 I2 deg DEd Declination (J2000)
35- 36 I2 arcmin DEm Declination (J2000)
38- 39 I2 arcsec DEs Declination (J2000)
41- 45 F5.3 deg rcore Core radius as fitted to the H-band radial
star density profile
47- 51 F5.3 deg rtid Tidal radius as fitted to the H-band radial
star density profile
53- 54 I2 arcmin-2 Dc Central star density in stars/arcmin2 as
fitted to H-band radial star density profile
56- 58 I3 --- Dcont ?=-99 Star density contrast in the H band (1)
60- 64 I5 --- N Number of stars in the cluster as obtained
using eq. (3) and the star density profile in
the H band
66- 70 I5 --- Nc Corrected number of stars in the cluster
determined using eq. (4) at an apparent
magnitude of 15 in the H band
72- 77 F6.3 --- logRN ?=99.0 Measure logRN as determined in
Sect. 4.4 (2)
79 I1 --- Q [0,6] Quality flag determined from our analysis
of the radial density profile fit (3)
81- 86 I06 --- Qall Detailed quality flags (3)
88-118 A31 --- Ident Name of possible known cluster with erroneous
coordinates in SIMBAD
--------------------------------------------------------------------------------
Note (1): determined as ratio of the central star density and the square
root of the background star density. Values of 99 indicate objects
with a fitted background star density of zero.
Note (2): RN=(POp/PGl)/(681/86), where POp is the Open cluster
probability and PGl the globular cluster probability. If logRN is
negative, the object is probably a globular cluster, otherwise it is
an open cluster. Values of 99.0 indicate cluster candidates with
PGl=0.
Note (3): the details are in Sect. 4.2 of the paper.
Q contains the number of negative tests (i.e. digits set to 1) in Qall.
Qall is a 6-digit binary number identifying which of the quality
tests are negative:
#1 = the cluster is detected automatically (0) or manually (1);
#2 = the scatter of the three fitted core radii is larger than 30% (1)
or smaller (0);
#3 = the scatter of the three fitted tidal radii is larger than 66% (1)
or smaller (0);
#4 = the contrast of the central to background star density
[Ic/sqrt(Ibg)] in all filters is larger than five (0) or not (1);
#5 = the ratio of tidal to core radius in all three filters is
between 3 and 45 (0) or not (1);
#6 = the core radius in all three filters is larger than twice the
error of the coordinates, i.e. 0.01° (0) or not (1).
--------------------------------------------------------------------------------
Acknowledgements:
Dirk Froebrich, df(at)star.kent.ac.uk
(End) Patricia Vannier [CDS] 28-Aug-2007