Aperture synthesis study of neutral hydrogen in NGC 2403 and NGC 4236. II. Discussion

Journal Article · Tue May 01 04:00:00 EDT 1973 · Astron. Astrophys., v. 24, no. 3, pp. 411-419

OSTI ID:4366280

Shostak, G S

For both NGC 2403 and NGC 4236 the extert of their H I distributions, as defined by 20% contour levels, is coincident with their optical extent. Both distributions exhibit bright, unresolved lumps situated in regions of prominent H II emission. The rotational velocities in NGC 2403 reach a maximum at 9 kpc, thereafter remainlng relatively constant, thus suggesting that the bulk of this galaxy's mass lies outside its optical radius. NGC 4236, assumed to be a barred spiral, exhibits solid-body rotation over the length of the bar. Peculiar motions in NGC 2403 of ~l0 km s/sup -1/ are observed, and are consistent in position and amplitude with the nonlinear density-wave theory of spiral structure. Upper limits to the fractional H I masses of these objects are l0% (NGC 2403) and 9% (NGC 4236). (auth)

• Research Organization: California Inst. of Tech., Pasadena
• NSA Number: NSA-29-013590
• OSTI ID: 4366280
• Journal Information: Astron. Astrophys., v. 24, no. 3, pp. 411-419, Journal Name: Astron. Astrophys., v. 24, no. 3, pp. 411-419; ISSN AAEJA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

*GALAXIES-- H1 REGIONS
*H1 REGIONS-- DISTRIBUTION
ANGULAR MOMENTUM
H2 REGIONS
MASS
MOTION
N56500* --Physics (Astrophysics & Cosmology)--Galaxies