J/A+A/448/189 IzJHK photometry of IC4665 (de Wit+, 2006)
Exploring the lower mass function in the young open cluster IC 4665.
de Wit W.J., Bouvier J., Palla F., Cuillandre J.C., James D.J.,
Kendall T.R., Lodieu N., McCaughrean M.J., Moraux E., Randich S., Testi L.
<Astron. Astrophys. 448, 189 (2006)>
=2006A&A...448..189D 2006A&A...448..189D
ADC_Keywords: Clusters, open ; Photometry, infrared
Keywords: open clusters and associations: individual: IC 4665 -
stars: low mass, brown dwarfs - stars: mass function -
techniques: photometric
Abstract:
We present a study of the young (30-100Myr) open cluster IC4665 with
the aim to determine the shape of the mass function well into the
brown dwarf regime. We photometrically select 691 low-mass and 94
brown dwarf candidate members over an area of 3.82 square degrees
centred on the cluster. K-band follow-up photometry and Two-Micron
All-Sky Survey (II/246) data allow a first filtering of contaminant
objects from our catalogues. A second filtering is performed for the
brightest stars using proper motion data provided by the Tycho-2
(I/259) and UCAC2 (I/289) public catalogues. Contamination by the
field population for the lowest mass objects is estimated using same
latitude control fields. We fit observed surface densities of various
cluster populations with King profiles and find a consistent tidal
radius of 1.0 degree. The presence of possible mass segregation is
discussed. In most respects investigated, IC4665 is similar to other
young open clusters of similar age: (1) an estimate of the mass
function in the low-mass regime and crossing the hydrogen burning
limit results in a power law description with slope -0.6, (2) a
fraction of BD to total members between 10-19%, (3) a cusp in the mass
function is seen at about the substellar boundary, (4) the best-fit
lognormal function to the full mass distribution shows an average
member mass of 0.32M☉ if IC4665 has an age of 50Myr.
Description:
The table contains the R.A., Dec., optical and near-IR photometry of
candidate members studied in the paper. Optical broad-band photometry
is taken with the CFHT 12k camera in the Mould I band and CFHT z band
(for effective transmission profile of the z band see e.g. Moraux et
al., 2003, Cat. J/A+A/400/891). Near-IR photometry 2MASS (II/246)
JHK is listed when a cross-correlation is found, requiring that the
2MASS counterpart has fiducial measurements, i.e. with an error
estimate. Otherwise a value of 0 is adopted. In a number of cases
CFHT-IR K-band data is listed, these cases are flagged in the table
(see paper); CFHT-IR K-band measurements have typical uncertainties
between 0.03 (for K=15) and 0.08 (for K=18).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 105 785 Coordinates and photometry of candidate members
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/194 : Photometric study of IC 4665 (McCarthy+ 1969)
J/AJ/105/1441 : IC 4665 (Prosser 1993)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- --- [IC4665]
8- 26 A19 --- Name Name (JHHMMSS.ss+DDMMSS.s) (1)
28- 29 I2 h RAh Right ascension (J2000)
31- 32 I2 min RAm Right ascension (J2000)
34- 38 F5.2 s RAs Right ascension (J2000)
40 A1 --- DE- Declination sign
41- 42 I2 deg DEd Declination (J2000)
44- 45 I2 arcmin DEm Declination (J2000)
47- 50 F4.1 arcsec DEs Declination (J2000)
52- 57 F6.3 mag Imag Mould I band
59- 64 F6.3 mag zmag CFHT z band
66- 71 F6.3 mag Jmag ?=- 2MASS (II/246) J band
73- 77 F5.3 mag e_Jmag ?=- Uncertainty 2MASS J band
79- 84 F6.3 mag Hmag ?=- 2MASS (II/246) H band
86- 90 F5.3 mag e_Hmag ?=- Uncertainty 2MASS H band
92- 97 F6.3 mag Kmag ?=- 2MASS (II/246) K band or CFHT-IR K band
99-103 F5.3 mag e_Kmag ?=- Uncertainty K band
105 I1 --- f_Kmag [1]? 1: K-band from CFHT-IR
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Note (1): Objects identified as [DBP2006] JHHMMSS.ss+DDMMSS.s in Simbad
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Acknowledgements: Willem-Jan de Wit, Willem-Jan.De-Wit(at)obs.ujf-grenoble.fr
(End) Patricia Vannier [CDS] 02-Mar-2006