Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-05-02
Astronomy and Astrophysics
Astrophysics
10 pages, 6 figures, ApJ Accepted. Some changes to technique
Scientific paper
10.1086/524374
Ongoing accretion onto galactic disks has been recently theorized to progress via the unstable cooling of the baryonic halo into condensed clouds. These clouds have been identified as analogous to the High-Velocity Clouds (HVCs) observed in HI in our Galaxy. Here we compare the distribution of HVCs observed around our own Galaxy and extra-planar gas around the Andromeda galaxy to these possible HVC analogs in a simulation of galaxy formation that naturally generates these condensed clouds. We find a very good correspondence between these observations and the simulation, in terms of number, angular size, velocity distribution, overall flux and flux distribution of the clouds. We show that condensed cloud accretion only accounts for ~ 0.2 M_solar / year of the current overall Galactic accretion in the simulations. We also find that the simulated halo clouds accelerate and become more massive as they fall toward the disk. The parameter space of the simulated clouds is consistent with all of the observed HVC complexes that have distance constraints, except the Magellanic Stream which is known to have a different origin. We also find that nearly half of these simulated halo clouds would be indistinguishable from lower-velocity gas and that this effect is strongest further from the disk of the galaxy, thus indicating a possible missing population of HVCs. These results indicate that the majority of HVCs are consistent with being infalling, condensed clouds that are a remnant of Galaxy formation.
Peek Joshua E. G.
Putman Mary E.
Sommer-Larsen Jesper
No associations
LandOfFree
Ongoing Galactic Accretion: Simulations and Observations of Condensed Gas in Hot Halos 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 Ongoing Galactic Accretion: Simulations and Observations of Condensed Gas in Hot Halos, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ongoing Galactic Accretion: Simulations and Observations of Condensed Gas in Hot Halos will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-496238