Astronomy and Astrophysics – Astrophysics
Scientific paper
Jan 1997
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997stin...9720925b&link_type=abstract
Masters Thesis, AD-A320127; AFIT-96-137 Dept. of Physics
Astronomy and Astrophysics
Astrophysics
Dark Matter, Mass To Light Ratios, Massive Stars, Star Formation, Velocity Measurement, Dwarf Stars, Interstellar Matter, Astrophysics, Dwarf Galaxies, Supernovae, Ultraviolet Radiation, Hydrogen, Stellar Evolution, Neutron Stars
Scientific paper
High-precision velocity measurements of faint individual stars in the Galactic dwarf spheroidal galaxy Draco indicate that the mass-to-light ratio in this system may be as high as approximately 100. Various possible forms of dark matter have been proposed for this class of objects, but a more recent analysis based on the Projected Mass Estimator technique seems to suggest that the non-luminous mass is distributed and may trace the stellar population. Here, we examine in detail the possible contribution of H2 to the dark matter content of Draco and conclude that most of its mass may be in the form of approximately 10 to 100 M H2 clouds if the typical dust grain size is at least approximately 90 times larger (i.e., approx. greater than 48 microns) than in our galaxy. This may be consistent with the fact that the dominant dust destroying mechanisms (e.g., supernova shocks) that suppress the average grain size in the galactic plane are absent in typical dwarf spheroidals. Thus the absence of dynamical processes (such as supernova explosions) that would normally induce massive star formation (which is non-existent in Draco) may also account for the large grain size. The lack of any observed extinction in this system would be consistent with the very low areal covering fraction (approx. 0.1 - 1%) of the clouds. We show that the predicted H content in Draco is then below current 21 cm detection limits, and that even NICMOS on HST would be hard pressed to detect the prominent J and K band emission lines of excited H2.
No associations
LandOfFree
The Hydrogen Contribution to the Dark Matter in Draco does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Hydrogen Contribution to the Dark Matter in Draco, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Hydrogen Contribution to the Dark Matter in Draco will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1199134