J/MNRAS/461/1734 HAWK-I JHK photometry of the Orion Nebula Cloud (Drass+, 2016)
The bimodal initial mass function in the Orion nebula cloud.
Drass H., Haas M., Chini R., Bayo A., Hackstein M., Hoffmeister V.,
Godoy N., Vogt N.
<Mon. Not. R. Astron. Soc., 461, 1734-1744 (2016)>
=2016MNRAS.461.1734D 2016MNRAS.461.1734D (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Infrared sources ; Photometry, infrared
Keywords: brown dwarfs - stars: formation - dust, extinction - infrared: stars
Abstract:
Due to its youth, proximity and richness, the Orion nebula cloud (ONC)
is an ideal testbed to obtain a comprehensive view on the initial mass
function (IMF) down to the planetary mass regime. Using the HAWK-I
camera at the VLT, we have obtained an unprecedented deep and wide
near-infrared JHK mosaic of the ONC (90 per cent completeness at K
∼19.0mag, 22x28 arcmin2). Applying the most recent isochrones and
accounting for the contamination of background stars and galaxies, we
find that ONC's IMF is bimodal with distinct peaks at about 0.25 and
0.025M☉ separated by a pronounced dip at the hydrogen burning
limit (0.08M☉), with a depth of about a factor of 2-3 below the
log-normal distribution. Apart from ∼920 low-mass stars
(M<1.4M☉) the IMF contains ∼760 brown dwarf candidates and ∼160
isolated planetary mass object candidates with M>0.005M☉, hence
about 10 times more substellar candidates than known before. The
substellar IMF peak at 0.025M☉ could be caused by brown dwarfs
and isolated planetary mass objects which have been ejected from
multiple systems during the early star formation process or from
circumstellar discs.
Description:
Using the HAWK-I camera at the VLT on 2008 November 8-11, we
obtained a large 22x28arcmin2 and deep image mosaic of the ONC in
the JHK filters centred at 1.25, 1.65 and 2.15um (i.e. Ks here for
short denoted as K) under good seeing conditions (full width at
half-maximum <0.7arcsec).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 78 4340 Catalogue of the HAWK-I sources
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See also:
J/A+A/502/883 : Very low mass ONC stars I photometry (Rodriguez-Ledesma+ 2009)
J/AJ/139/950 : JHKs photometry in ONC (Robberto+, 2010)
J/ApJ/722/1092 : Optical photometry of the ONC. II. (Da Rio+, 2010)
J/ApJ/733/50 : ONC mid-IR photometric monitoring (Morales-Calderon+, 2011)
J/A+A/593/A7 : NH and AV Towards YSOs in the ONC (Hasenberger+, 2016)
J/AJ/150/132 : JHK photometry of 1203 variables in ONC (Rice+, 2015)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 13 F13.10 deg RAdeg Right ascension (J2000)
15- 25 F11.8 deg DEdeg Declination (J2000)
29- 36 F8.5 mag Jmag HAWK-I J magnitude (1.25um)
38- 44 F7.5 mag e_Jmag rms uncertainty on Jmag
46- 53 F8.5 mag Hmag HAWK-I H magnitude (1.65um)
55- 61 F7.5 mag e_Hmag rms uncertainty on Hmag
63- 70 F8.5 mag Ksmag HAWK-I Ks magnitude (2.15um)
72- 78 F7.5 mag e_Ksmag rms uncertainty on Ksmag
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 27-Nov-2017