Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-02-27
Astrophys.J. 644 (2006) L1-L4
Astronomy and Astrophysics
Astrophysics
4 Pages, 4 Figures, Submitted to ApJL, Printing in colour recommended
Scientific paper
10.1086/505489
Based on 19 high-resolution N-body/gas-dynamical galaxy formation simulations in the LCDM cosmology it is shown, that for a galaxy like the Milky Way, in addition to the baryonic mass of the galaxy itself, about 70% extra baryonic mass should reside around the galaxy (inside of the virial radius), chiefly in the form of hot gas. Averaging over the entire field galaxy population, this ``external'' component amounts to 64-85% of the baryonic mass of the population itself. These results are supported by the recent detection of very extended, soft X-ray emission from the halo of the quiescent, massive disk galaxy NGC 5746. Some of the hot gas may, by thermal instability, have condensed into mainly pressure supported, warm clouds, similar to the Galactic High Velocity Clouds (HVCs). Based on an ultra-high resolution cosmological test simulation of a Milky Way like galaxy (with a gas particle mass and gravity softening length of only 7600 h^-1 Msun and 83 h^-1 pc,respectively), it is argued, that the hot gas phase dominates over the warm gas phase, in the halo. Finally, an origin of HVCs as ``leftovers'' from filamentary, ``cold'' accretion events, mainly occurring early in the history of galaxies, is proposed.
No associations
LandOfFree
Where are the ``Missing'' Galactic Baryons? 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 Where are the ``Missing'' Galactic Baryons?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Where are the ``Missing'' Galactic Baryons? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-387537