High mass-loss AGB stars detected by MSX in the "intermediate" and "outer" Galactic bulge

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dc.creatorOjha, D. K.
dc.creatorTej, A.
dc.creatorSchultheis, M.
dc.creatorOmont, A.
dc.creatorSchuller, F.
dc.date2007-08-04
dc.date.accessioned2026-07-07T08:22:14Z
dc.date.available2026-07-07T08:22:14Z
dc.descriptionWe present a study of MSX point sources in the Galactic bulge (|l| < 3 deg, 1 deg < |b| < 5 deg), observed at A, C, D and E-band (8 to 21 micron), with a total area ~ 48 deg^2. We discuss the nature of the MSX sources (mostly AGB stars), their luminosities, the interstellar extinction, the mass-loss rate distribution and the total mass-loss rate in the bulge. The MIR data of MSX point sources have been combined with the NIR (J, H and Ks) data of 2MASS survey. The cross-identification was restricted to Ks-band detected sources with Ks <= 11 mag. However, for those bright MSX D-band sources ([D] < 4.0 mag), which do not satisfy this criteria, we have set no Ks-band magnitude cut off. The relation between Mdot and (Ks-[15])0 was used to derive the mass-loss rate of each MSX source in the bulge fields. Except for very few post-AGB stars, PNe and OH/IR stars, a large fraction of the detected sources at 15 micron (MSX D-band) are AGB stars well above the RGB tip. A number of them show an excess in ([A]-[D])0 and (Ks-[D])0 colours, characteristic of mass-loss. These colours, especially (Ks-[D])0, enable estimation of the mass-loss rates (Mdot) of the sources in the bulge fields which range from 10^{-7} to 10^{-4} Msun/yr. Taking into consideration the completeness of the mass-loss rate bins, we find that the contribution to the integrated mass-loss is probably dominated by mass-loss rates larger than 3x10^{-7} Msun/yr and is about 1.96 x 10^{-4} Msun/yr/deg^2 in the "intermediate" and "outer" bulge fields of sources with mass-loss rates, Mdot > 3x10^{-7} Msun/yr. The corresponding integrated mass-loss rate per unit stellar mass is 0.48x10^{-11} yr^{-1}. Apart from this, the various MIR and NIR CC and CM diagrams are discussed in the paper to study the nature of the stellar population in the MSX bulge fields.
dc.description18 pages, 18 figures: Accepted for the publication in MNRAS; Full resolution figures available at http://www.tifr.res.in/~ojha/bulge_mass-loss.ps
dc.identifierhttps://arxiv.org/abs/0708.0613
dc.identifierhttp://arxiv.org/abs/0708.0613
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/135583
dc.subjectAstrophysics
dc.titleHigh mass-loss AGB stars detected by MSX in the "intermediate" and "outer" Galactic bulge
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