J/A+A/532/A103 Photometry and proper motions in IC4665 (Lodieu+, 2011)
The mass function of IC4665 revisited by the UKIDSS Galactic Clusters Survey.
Lodieu N., de Wit W.J., Carraro G., Moraux E., Bouvier J., Hambly N.C.
<Astron. Astrophys. 532, A103 (2011)>
=2011A&A...532A.103L 2011A&A...532A.103L
ADC_Keywords: Clusters, open ; Photometry, infrared ; Proper motions ;
Spectral types
Keywords: techniques: photometric - stars: low-mass - brown dwarfs -
stars: luminosity function, mass function - infrared: stars -
open clusters and associations: individual: IC 4665
Abstract:
Knowledge of the mass function in open clusters constitutes one way to
constrain the formation of low-mass stars and brown dwarfs along with
the knowledge of the frequency of multiple systems and the properties
of disks.
The aim of the project is to determine the shape of the mass function
in the low-mass and substellar regimes in the pre-main sequence
(27Myr) cluster IC4665 located at 350pc from the Sun.
We have cross-matched the near-infrared photometric data from the
Eighth Data Release (DR8) of the UKIRT Infrared Deep Sky Survey
(UKIDSS) Galactic Clusters Survey (GCS) with previous optical data
obtained with the Canada-France-Hawaii (CFH) wide-field camera to
improve the determination of the luminosity and mass functions in
the low-mass and substellar regimes. The availability of i and z
photometry taken with the CFH12K camera on the Canada France Hawaii
Telescope added strong constraints to the UKIDSS photometric selection
in this cluster located in a dense region of our Galaxy.
We have derived the luminosity and mass functions of the cluster
down to J=18.5mag, corresponding to masses of ∼0.025M☉ at
the distance and age of IC4665 according to theoretical models. In
addition, we have extracted new candidate members down to ∼20 Jupiter
masses in a previously unstudied region of the cluster. We have
derived the mass function over the 0.6-0.04M☉ mass range and
found that it is best represented by a log-normal function with a peak
at 0.25-0.16M☉, consistent with the determination in the
Pleiades.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 125 493 Coordinates, photometry, proper motion, luminosity,
and mass for confirmed optical candidates
tableb1.dat 113 161 Coordinates, photometry and proper motion of
161 optical candidates rejected as members
tablec1.dat 97 879 Coordinates, photometry and proper motion of new
cluster member candidates from the GCS
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See also:
II/314 : UKIDSS-DR8 LAS, GCS and DXS Surveys (Lawrence+ 2012)
J/A+A/448/189 : IzJHK photometry of IC4665 (de Wit+, 2006)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- Name Name following IAU nomenclature (G1)
24- 25 I2 h RAh Right ascension (J2000.0)
27- 28 I2 min RAm Right ascension (J2000.0)
30- 34 F5.2 s RAs Right ascension (J2000.0)
36 A1 --- DE- Declination sign (J2000.0)
37- 38 I2 deg DEd Declination (J2000.0)
40- 41 I2 arcmin DEm Declination (J2000.0)
43- 46 F4.1 arcsec DEs Declination (J2000.0)
48- 53 F6.3 mag imag I-band magnitude from the CFH12K
55- 60 F6.3 mag zmag z-band magnitude from the CFH12K
62- 67 F6.3 mag Zmag UKIDSS/Z-band magnitude from UKIDSS GCS DR8
69- 74 F6.3 mag Ymag UKIDSS/Y-band magnitude from UKIDSS GCS DR8
76- 81 F6.3 mag Jmag UKIDSS/J-band magnitude from UKIDSS GCS DR8
83- 88 F6.3 mag Hmag UKIDSS/H-band magnitude from UKIDSS GCS DR8
90- 95 F6.3 mag Kmag UKIDSS/K-band magnitude from UKIDSS GCS DR8
97-104 F8.2 mas/yr pmRA Proper motion in right ascension
106-113 F8.2 mas/yr pmDE Proper motion in declination
115-119 F5.2 [Lsun] logL Star luminosity
121-125 F5.3 Msun Mass Star mass
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Byte-by-byte Description of file: tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 22 A22 --- Name Name following IAU nomenclature (G1)
24- 25 I2 h RAh Right ascension (J2000.0)
27- 28 I2 min RAm Right ascension (J2000.0)
30- 34 F5.2 s RAs Right ascension (J2000.0)
36 A1 --- DE- Declination sign (J2000.0)
37- 38 I2 deg DEd Declination (J2000.0)
40- 41 I2 arcmin DEm Declination (J2000.0)
43- 46 F4.1 arcsec DEs [0/60] Declination (J2000.0)
48- 53 F6.3 mag imag I-band magnitude from the CFH12K
55- 60 F6.3 mag zmag z-band magnitude from the CFH12K
62- 67 F6.3 mag Zmag ?=99.999 UKIDSS/Z-band magnitude from GCS DR8
69- 74 F6.3 mag Ymag UKIDSS/Y-band magnitude from UKIDSS GCS DR8
76- 81 F6.3 mag Jmag UKIDSS/J-band magnitude from UKIDSS GCS DR8
83- 88 F6.3 mag Hmag UKIDSS/H-band magnitude from UKIDSS GCS DR8
90- 95 F6.3 mag Kmag UKIDSS/K-band magnitude from UKIDSS GCS DR8
97-104 F8.2 mas/yr pmRA Proper motion in right ascension
106-113 F8.2 mas/yr pmDE Proper motion in declination
115-119 F5.2 [Lsun] logL ? Star luminosity
121-125 F5.3 Msun Mass ? Star mass
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Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 22 A22 --- Name Name following IAU nomenclature (G1)
24- 25 I2 h RAh Right ascension (J2000.0)
27- 28 I2 min RAm Right ascension (J2000.0)
30- 34 F5.2 s RAs Right ascension (J2000.0)
36 A1 --- DE- Declination sign (J2000.0)
37- 38 I2 deg DEd Declination (J2000.0)
40- 41 I2 arcmin DEm Declination (J2000.0)
43- 46 F4.1 arcsec DEs [0/60] Declination (J2000.0)
48- 53 F6.3 mag Zmag UKIDSS/Z-band magnitude from UKIDSS GCS DR8
55- 60 F6.3 mag Ymag UKIDSS/Y-band magnitude from UKIDSS GCS DR8
62- 67 F6.3 mag Jmag UKIDSS/J-band magnitude from UKIDSS GCS DR8
69- 74 F6.3 mag Hmag UKIDSS/H-band magnitude from UKIDSS GCS DR8
76- 81 F6.3 mag Kmag UKIDSS/K-band magnitude from UKIDSS GCS DR8
83- 89 F7.2 mas/yr pmRA ?=99.99 Proper motion in right ascension
91- 97 F7.2 mas/yr pmDE ?=99.99 Proper motion in declination
115-119 F5.2 [Lsun] logL ? Star luminosity
121-125 F5.3 Msun Mass ? Star mass
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Global notes:
Note (G1): Names as HH:MM:SS.ss+DD:MM:SS.s,
idenfied as in Simbad.
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Acknowledgements:
Nicolas Lodieu, nlodieu(at)iac.es
(End) Nicolas Lodieu [IAC Tenerife, Spain], Patricia Vannier [CDS] 09-Jun-2011