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La formation d'étoiles massives dans la Galaxie vue par le relevé infrarouge ISOGAL

Abstract : This thesis deals with the study of recent star formation in the Galaxy and is based on the ISOGAL infrared imaging survey, which contains about 400 observations of the Galactic Bulge and Disk at 7 or 15 microns. The critical data reduction and the use of a PSF fitting procedure to extract the point sources enabled the publication of a catalogue containing 100,000 sources. The bulk of these sources are interpreted as evolved stars in the RGB or AGB stage, but a few thousand of them are likey to be young stellar objects enshrouded in dust envelopes. In the inner Galactic Bulge, 300 ISOGAL sources are considered as forming stars, and more than 200 ISO or MSX bright sources are interpreted as M supergiant or massive AGB stars. A rough average star formation rate over the last million years in this central area of the Galaxy is derived from this sample of young stars. An approximate estimate for the past ~50 Myr is also inferred from the inventory of sources interpreted as M supergiants. Currently, about 700 YSO candidates are extracted from the complete ISOGAL catalogue. Outside the inner bulge, ~100 of them show all the features of enshrouded young stellar objects. The nature of the others is still uncertain and would be clarified by complementary observations. The nature of a large number of other sources, including faint ones that were only detected at 15 microns, is also uncertain.
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Contributor : Frederic Schuller <>
Submitted on : Wednesday, April 7, 2004 - 6:30:18 PM
Last modification on : Wednesday, December 9, 2020 - 3:05:26 PM
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  • HAL Id : tel-00003754, version 1


Frédéric Schuller. La formation d'étoiles massives dans la Galaxie vue par le relevé infrarouge ISOGAL. Astrophysique [astro-ph]. Université Pierre et Marie Curie - Paris VI, 2002. Français. ⟨tel-00003754⟩



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