The Interstellar Medium of External Galaxies

This page contains html links to all of the articles used in Astronomy 208 in the discussion of the ISM in other galaxies on 12/10/98, and some others.


Outline of the Lecture on the ISM in External Galaxies, including Articles & Figures Used


The Extent of Galaxies

How far "out" does the ISM go?

Digel, S., De Geus, E. and Thaddeus, P. 1994, Molecular clouds in the extreme outer galaxy, ApJ, 422, 92-101.

Figure 1: Column density of H I at R=18 to 30 kpc in the Milky Way
Figure 4: Locations of Distant clouds in the Milky Way
High-Velocity Clouds

Danly, L., Albert, C.E. and Kuntz, K.D. 1993, A Determination of the Distance to the High-Velocity Cloud Complex M, ApjL, 416, L29.

Figure 1: H I spectra and uv-absorption spectra used in distance determination
The Magellanic Stream, "Bridges," & "Tails"

Wayte, S.R. 1989, The Magellanic Stream - New observations, Astronomical Society of Australia, Proceedings, 8, 195-203.

Figure 1: Global Distribution of H I in the Magellanic Stream
Figure 8: Distribution of Extreme- and High-Velocity Clouds associated with the Stream

The Origin of the Magellanic Stream, by Ben Moore & Marc Davis, 1996 (html document)

Discussion: HVC's & Galaxy Interactions
Intergalactic Gas: problem: normal (processed) abundances
Galactic Fountain: problem: some clouds too fast for MW potential
Tidal Bridges/Stripping/Tails: does this explain all HVCs?
Evidence of galaxy interaction/mergers: e.g. Cen A


Metallicity Variations

The Large Magellanic Cloud

Cohen, R.S., Dame, T.M., Garay, G., Montani, J., Rubio, M. and Thaddeus, P. 1988, A complete CO survey of the Large Magellanic Cloud, ApJL, 331, L95-L99.

Figure 1: CO map of the LMC
Figure 2: Luminosity-Linewidth Relation, showing lower metallicity than Milky Way
Optical Image of the LMC
Varitions with Galaxy Type

Richer, M.G. and McCall, M.L. 1995, Oxygen abundances in diffuse ellipticals and the metallicity-luminosity relations for dwarf galaxies, ApJ, 445, 642-659.


The 30 Doradus Region in the LMC

HST Data: Scowen, P.A. et al. 1998, Ionization Structure in the 30 Doradus Nebula as seen with Hubble Space Telescope Wide Field Planetary Camera 2, AJ, 116, 163. (source of handouts)

Models: Tenorio-Tagle, G. and Medina-Tanco, G.A. 1998, Star Clusters and the Structure of the ISM: Tunnels and Wakes in Giant Extragalactic H II Regions, ApJ, 503, 171.


Star-Formation and Magnetic Fields in External Galaxies

Rand, R.J., Kulkarni, S.R. and Rice, W. 1992, Star formation and the distribution of HI and infrared emission in M51, ApJ, 390, 66-78.

Figure 1: CO, H-alpha, H I and red continuum images of M51, compared

Scarrott, S.M., Ward-Thompson, D. and Warren-Smith, R.F. 1987, Evidence for a spiral magnetic field configuration in the galaxy M51, MNRAS, 224, 299-305.

Figure 3: Optical Polarization Map of M51
Magnetic Fields in External Galaxies
M51: a face-on spiral

Beck, R., Wielebinski, R. and Klein, U. 1987, The magnetic field in M51, A&A, 186, 95-98.

Figure: Polarization of Radio Synchrotron Emission in M51

Neininger, N. 1992, The magnetic field structure of M51, A&A, 263, 30-36.

Berkhuijsen, E.M. et al. 1997, Magnetic Fields in the Disk and Halo of M51, A&A, 318, 700.

Figure: Synchrotron Polarization Maps at Several Wavelengths (handed out).

NGC 4631: halo of an edge-on galaxy

Hummel, E., Beck, R. and Dahlem, M. 1991, The magnetic field structure in the radio halos of NGC 891 and NGC 4631, A&A, 248, 23-29.

Figure: Polarization of Radio Synchrotron Emission in NGC 4631


The Structure of the ISM in Dwarf/Irregular Galaxies

Puche, D., Westpfahl, D., Brinks, E. and Roy, J.-R. 1992, Holmberg II - A laboratory for studying the violent interstellar medium, AJ, 103, 1841-1858, 2115-2123. (This is the galaxy where the HI distribution, presumably created by SN shells, mimics spiral structure in extensive VLA maps.)

Figure 12: Location of the H I holes in Ho II
Plates: to see plates, enter plate number below at the bottom of the main article page.
Plate 107: Maps of HI integrated intensity in Ho II
Plate 109: H-alpha image of the central 5x5 arcmin of Ho II
 


Other interesting recent results on the ISM of other galaxies:

Rotation Curve of the Milky Way and Other Galaxies

Vallee, J.P. 1994, Galactic magnetism and the rotation curves of M31 and the Milky Way, ApJ, 437, 179-183.

Figure 1: Magnetic Field as a Function of Radial Distance in M31
Figure 2: Magnetic Field as a Function of Radial Distance in the Milky Way
Figures 3 & 4: Rotation Curves for M31 and the Milky Way, respectively


This page prepared by Alyssa A. Goodman.