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J/A+A/???/??? Catalogue of bright YSO candidates in ISOGAL (Felli+, 2002)
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Young massive stars in the ISOGAL survey II The catalogue of bright YSO
candidates
Felli M., Testi L., Schuller F., Omont A.

=2002A&A...???..???F
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ADC_Keywords: Stars: formation - Infrared photometry
Keywords: Stars:formation - HII regions - Galaxy:structure - Infrared:star

Abstract:
The 7 and 15~$\mu$m observations of selected fields in the Galactic Plane
obtained with ISOCAM during the ISOGAL program offer an unique
possibility to search for previously unknown YSOs, undetected by
IRAS because of lower sensitivity or confusion problems. In a
previous paper (Felli et al.~2000) we established criteria of
general validity to select YSOs from the much larger population of
Post Main Sequence (Post-MS) stars present in the ISOGAL fields by
comparing radio and IR observations of five fields located at
l$\sim$+45$^{\circ}$. The selection was based primarily on the
position of the point sources in the [15] - [7]--[15] diagram, which
involves only ISOGAL data and allows to find possible YSOs using the
survey data alone. In the present work we revise the adopted
criteria by comparing radio-identified UC HII regions and ISOGAL
observations over a much larger region. The main indications of
the previous analysis are confirmed, but the criteria for selecting
YSO candidates had to be revised to select only bright objects, in
order to limit the contamination of the sample by Post-MS stars.
The revised criteria ([15]$\le$4.5, [7]--[15]$\ge$1.8) are then used
to extract YSO candidates from the ISOGAL Point Source Catalogue
in preparation. We select a total of 715 YSO candidates,
corresponding to $\sim$2\% of the sources with good detections at 7
and 15~$\mu$m. The results are presented in a table form that
provides an unique input list of small diameter, $\le 6$\arcsec,
Galactic YSO candidates. The global properties of the sample of
YSO candidates are briefly discussed.

Description:
Table of candidate YSOs extracted from the ISOGAL survey database.
For each source we report the ISOGAL name, the galactic coordinates
and the mid- and near-infrared photometry, based on the ISOGAL and
DENIS surveys. When found in the Becker et al. (1994, ApJS, 91, 347),
the name of the radio continuum counterpart is also reported.

File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 108 715 YSO candidates in the ISOGAL survey
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 24 A24 --- Name ISOGAL source name (based on J2000 coordinates)
26- 33 F8.4 deg Glon Galactic longitude
36- 42 F7.4 deg Glat Galactic latitude
44- 48 F5.2 mag [15] ISOGAL 15um magnitude
50- 54 F5.2 mag [7] ISOGAL 15um magnitude
56- 60 F5.2 mag Ks DENIS Ks magnitude, S=saturated, E=extended
62- 66 F5.2 mag J DENIS J magnitude, S=saturated, E=extended
68- 72 F5.2 mag I DENIS I magnitude, S=saturated, E=extended
74- 75 I2 --- Aid ISOGAL-DENIS association flag (1)
77- 78 I2 --- Sd DENIS YSO confidence flag (2)
80- 92 A13 --- Rname Radio source name (Becker et al. ApJS 91, 347)
94-107 A14 --- IGfield ISOGAL field
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Note (1): The ISOGAL-DENIS association flag is a measure of the reliability
of the association between the mid- and near-infrared source, a complete
discussion of this flag is given in (Schuller et al. 2002, in prep.).
The flag is set to "-1" if the ISOGAL field has not been covered by
the DENIS survey.
Note (2): The DENIS YSO confidence flag offer an additional confidence
criterion for the nature of the candidate. The value is "-1" if the
source is outside the region observed by DENIS. A complete description
of this flag is given in Sect.5 of the paper.
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(End) Leonardo Testi [INAF-Arcetri, Italy] 28-Jun-2002