1997/10/16 by Siow-Wang Lee, Siow‐Wang Lee, J. Irwin +1 · 1 citation
Mathematics · Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Barred spiral galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Halo #Interacting galaxy #Irregular galaxy #Mathematics #Physics #Scientific Research and Discoveries #Spiral (railway) #Spiral galaxy #astro-ph
paper · pdf · doi:10.1086/304840
Latex 23 pages including 13 postscript figures, to be published in the Nov. 20 issue of ApJ
arxiv created 1997/10/16 · openalex publication_date 1997/11/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The first detailed VLA mapping of the neutral hydrogen distribution in the isolated , edge-on spiral galaxy NGC 3044 is presented. Physical parameters such as M H I , M T , etc. determined for this galaxy are typical for galaxies of its morphological class (SBc). We have modeled the H I spectra in order to derive its global density and velocity distributions. An H I scale height of 420 h -1 pc is thus found. This can be compared to the impressive radio continuum halo, previously found to extend to 8 kpc above the midplane. The present study reveals an asymmetry in the H I distribution as well as numerous high-latitude H I structures at various galactocentric radii. The approaching (northwest) side of the galaxy is 14% less massive than the receding side and its rotation curve does not reach terminal velocity. The rotation curve of the receding (southeast) side, however, resembles that of a normal galaxy. Twelve high-latitude features were cataloged, of which four exhibit the signature of an expanding shell. There is some correlation of these features with features observed in the radio continuum from independent data. The most massive shell (feature 10) extends out to 6 h -1 kpc above the galactic disk. The radii and masses of these shells range from 1.2-2.0 h -1 kpc and 1.6 × 10 7 -5.5 × 10 7 h -2 M ☉ , respectively. We have investigated the possibility that the supershells could have been produced by external impacting clouds, but conclude that this scenario is unattractive, given the age of the shells, the isolation of the galaxy, and the lack of any observed features sufficiently massive to form the shells in the vicinity of the galaxy. Therefore, an internal origin is suggested. Since the implied input energies from supernovae are extremely high (e.g., from 1.4 × 10 53 -7.4 × 10 55 h -2 ergs, corresponding to 400-74,000 supernovae), we suggest that some additional energy (e.g., from magnetic fields) may be needed to produce the observed supershells.