Young massive stars in the ISOGAL survey
II. The catalogue of bright YSO candidates
by
M. Felli, L. Testi, F. Schuller, A. Omont
Abstract:
The 7 and 15 um 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~+45 deg. 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]<=4.5, [7]--[15]>=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 ~2% of the
sources with good detections at 7 and 15 um. The results are presented in
a table form that provides an unique input list of small diameter,
<=6", Galactic YSO candidates. The global properties of the sample of YSO
candidates are briefly discussed.
Mantained by:
Leonardo Testi