Astronomy and Astrophysics – Astrophysics
Scientific paper
1998-06-23
Astronomy and Astrophysics
Astrophysics
10 pages; Latex; 1 encapsulated PS figure. Invited talk, ESO/ATNF International Workshop "Looking Deep in the Southern Sky", D
Scientific paper
We discuss the sources which are likely to dominate the ionizing field throughout the Local Group. In terms of the limiting flux to produce detectable H-alpha emission (4-10 x 10**3 phot/cm**2/s), the four dominant galaxies (M31, Galaxy, M33, LMC) have spheres of influence which occupy a small fraction (<10%) of the Local Volume. There are at least two possible sources of ionization whose influence could be far more pervasive: (i) a cosmic background of ionizing photons; (ii) a pervasive warm plasma throughout the Local Group. The COBE FIRAS sky temperature measurements permit a wide variety of plasmas with detectable ionizing fields. It has been suggested (Blitz et al. 1996; Spergel et al. 1996; Sembach et al. 1995, 1998) that a substantial fraction of high velocity clouds are external to the Galaxy but within the Local Group. Deep H-alpha detections are the crucial test of these claims and, indeed, provide a test bed for the putative Local Group corona.
No associations
LandOfFree
The Metagalactic Ionizing Field in the Local Group 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 Metagalactic Ionizing Field in the Local Group, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Metagalactic Ionizing Field in the Local Group will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-655955