J/A+A/316/102 JHK Photometry in NGC 6334 (Tapia+, 1996)
The embedded stellar population in northern NGC 6334
Tapia M., Persi P., Roth M.
<Astron. Astrophys. 316, 102 (1996)>
=1996A&A...316..102T 1996A&A...316..102T (SIMBAD/NED BibCode)
ADC_Keywords: Photometry, infrared
Keywords: infrared: stars - stars: formation - clusters: NGC 6334 cluster -
ISM: NGC 6334
Abstract:
JHK imaging photometry is reported of an area of approximately 2'x3'
centred on the far infrared source NGC 6334 I with limiting magnitudes
J=18.3, H=17.8 and K=16.2. More than 224 sources were detected in
K-band, increasing by a factor of more than seven the number of
objects found in previous near-IR surveys. Most of the sources are
located in an area of about 3500 square arcsec centered around the
massive young stellar object Irs1, which ionizes the compact HII
region NGC 6334 F. The location of these sources and the analysis of
the colour-colour and colour-magnitude diagrams suggest the presence
of an embedded and young stellar cluster of size ∼70" (0.6pc), and
stellar density of about 1200pc-3. The star formation efficiency is
estimated to be SFE≃0.25. Only a few of the most luminous stars of
the cluster were found to show large near-IR excesses but this may be
due to the non-detection, at the shortest wavelength, of the majority
of the highly reddened cluster members. The extinction of the region
is very variable with a maximum of AV>70 in Irs2 while the average
is <AV≥∼40. Very close to the position of an H2O maser associated
with NGC 6334 I(N), a contracting core at an earlier evolutionary
stage, we found six very red sources, one of which is a small and
diffuse nebula seen only at 2.2µm. Finally, the older and developed
HII region NGC 6334 E was found to be probably ionized by a small
cluster of at least 12 B0-B0.5 ZAMS stars.
For a description of the JHK photometric system, see e.g. GCPD/09
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1 62 224 Coordinates and photometry of sources
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See also:
J/A+A/357/1020 : JHK photometry in NGC 6334 IV (Persi+, 2000)
Byte-by-byte Description of file: table1
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Bytes Format Units Label Explanations
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1- 3 I3 --- No [1/224] Identification number
5- 6 I2 h RAh Right ascension (B1950)
8- 9 I2 min RAm Right ascension (B1950)
11- 15 F5.2 s RAs Right Ascension (B1950)
17 A1 --- DE- Declination sign
18- 19 I2 deg DEd Declination (B1950)
21- 22 I2 arcmin DEm Declination (B1950)
24- 27 F4.1 arcsec DEs Declination (B1950)
29 A1 --- l_Jmag Limit flag on J magnitude
30- 34 F5.2 mag Jmag ? J magnitude
36 A1 --- l_Hmag Limit flag on H magnitude
37- 41 F5.2 mag Hmag ? H magnitude
43- 47 F5.2 mag Kmag K magnitude
49- 58 A10 --- Notes See note (1)
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Note (1): (1) Outside J and H images.
(2) Irs3.
(3) Near-IR excess. (St) Straw et al. (1989ApJS...69...99S 1989ApJS...69...99S)
(4) Irs1. Phot. of components, in Paper I (Persi et al.,
1996A&A...307..591P 1996A&A...307..591P)
(St) Straw et al. (1989ApJS...69...99S 1989ApJS...69...99S)
(*) Probable exciting star of HII region E.
(Neb.) Nebular object
(H2 Knot) Molecular hydrogen emission knot
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Acknowledgements: Mauricio Tapia
(End) Patricia Bauer [CDS] 15-Apr-1996