J/MNRAS/361/211 JHK photometry of brown dwarfs in Orion (Lucas+, 2005)
A deep survey of brown dwarfs in Orion with Gemini.
Lucas P.W., Roche P.F., Tamura M.
<Mon. Not. R. Astron. Soc., 361, 211-232 (2005)>
=2005MNRAS.361..211L 2005MNRAS.361..211L
ADC_Keywords: Surveys ; Clusters, open ; Stars, pre-main sequence ;
Stars, dwarfs ; Photometry, infrared
Keywords: surveys - circumstellar matter - stars: formation -
stars: low-mass, brown dwarfs
Abstract:
We report the results of a deep near-infrared (JHK) survey of the
outer parts of the Trapezium Cluster with Gemini South/Flamingos.
396 sources were detected in a 26-arcmin2 area, including 138 brown
dwarf candidates, defined as M<0.075M☉ for an assumed age of
1Myr. Only 33 of the brown dwarf candidates are planetary mass
candidates with estimated masses in the range 0.003<M<0.012M☉.
In an extinction-limited sample (AV<5) complete to approximately
0.005M☉ (5MJup) the mass function appears to drop by a factor
of 2 at the deuterium burning threshold, i.e. at planetary masses.
After allowing for background contamination it is likely that
planetary mass objects at 3-13MJup number <10% of the cluster
population, with an upper limit of 13%. Analysis of the spatial
distribution of stars and brown dwarf candidates suggests that brown
dwarfs and very low-mass stars (M<0.1M☉) are less likely than
more massive stars to have wide (>150AU) binary companions.
Description:
Near-infrared imaging in the J (1.25um), H (1.65um) and K (2.2um)
bands was carried out at two epochs with the Flamingos I camera on the
Gemini South telescope at Cerro Pachon, Chile. All observations were
made in queue mode by observatory staff. The first data set was taken
on the nights of 2001 October 7, 10, 12, 15-17. One field was
observed, the camera pixel scale of 0.076arcsec yielding a field of
view of 156arcsec. The second data set, comprising two Flamingos
fields, was taken in 2002 with a science grade array of the same type
on the nights of October 29-31, and November 1, 2, 4 and 12.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 67 395 Source catalogue
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See also:
J/A+A/429/1007 : RIJHK phot. of VLM objects near eps Ori (Scholz+, 2005)
J/AJ/127/2856 : Brown dwarfs in the 2MASS Survey (Burgasser+, 2004)
J/MNRAS/356/89 : sigma Ori low-mass stars (Kenyon+, 2005)
J/AN/325/705 : RIJHKs of low-mass stars in sigma Ori (Bejar+, 2004)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [LRT2005] Sequential number
5- 12 A8 --- Name Coordinate based ID (SSs-MSS or MSSs-MSS))
13 A1 --- n_Name [e] Note on Name (1)
15- 16 I2 h RAh Right ascension (J2000.0) (2)
18- 19 I2 min RAm Right ascension (J2000.0)
21- 26 F6.3 s RAs Right ascension (J2000.0)
28 A1 --- DE- Declination sign (J2000.0)
29- 30 I2 deg DEd Declination (J2000.0)
32- 33 I2 arcmin DEm Declination (J2000.0)
35- 39 F5.2 arcsec DEs Declination (J2000.0)
41- 45 F5.2 mag Kmag K (2.2um) magnitude (3)
47- 51 F5.2 mag Hmag H (1.65um) magnitude (3)
53- 57 F5.2 mag Jmag J (1.25um) magnitude (3)
59- 61 A3 --- Flag [JHK] Flag about flux incertainty (4)
63 I1 --- r_Kmag Reference for K flux (5)
65 I1 --- r_Hmag Reference for H flux (5)
67 I1 --- r_Jmag Reference for J flux (5)
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Note (1): 395 sources are listed but Source 265 is a binary listed as a single
source because both components were saturated and barely resolved.
Note (2): Estimated precision in the world coordinate system is 0.5 arcseconds.
Note (3): Sources not detected in a passband have the dummy values:
0.000 = undetected sources
-1.000 = sources off the edge of the data mosaic
-2.000 = saturated sources not seen in other surveys
-3.000 = binaries unresolved in some passbands
Note (4): Highly uncertain fluxes (>0.2 mag) are indicated by letters
in this column denoting the passband(s) with uncertain flux.
Note (5): Sources in general have fluxes drawn from one or more datasets,
indicated separately for the K, H and J fluxes in that order.
The source is indicated by the following key:
0 = this survey
1 = Lucas et al., 2001MNRAS.326..695L 2001MNRAS.326..695L
2 = the 2MASS All Sky Survey, Cat. II/246
3 = the 2MASS 2nd Incremental Data Release (Cat. II/241)
4 = Hillenbrand & Carpenter, 2000, Cat. J/ApJ/540/236
5 = Muench et al., 2002, Cat. J/ApJ/573/366
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 10-Apr-2006