Accession Number:

AD0744679

Title:

Aperture Synthesis Study of Neutral Hydrogen in the Galaxies NGC 6946 and IC 342

Descriptive Note:

Corporate Author:

OWENS VALLEY RADIO OBSERVATORY PASADENA CA

Personal Author(s):

• Rogstad, D. H.
• Shostak, G. S.
• Rots, A. H.

Report Date:

1972-01-01

Pagination or Media Count:

33.0

Abstract:

Synthesis observations of netural hydrogen emission in the two spiral galaxies NGC 6946 and IC 342 are presented. The velocity resolution is 21 kms and the angular resolution is 2 and 4 min of arc for NGC 6946 and IC 342 respectively. Results are presented in the form of contour maps of the integral and mean velocity of the HI profile at each position in the galaxy, as well as a line profile for each galaxy as a whole. Both galaxies evidence a central depression in their HI distributions. The rotation curves have steep central gradients with rather constant velocities once the maximal velocity is reached. The HI mass for NGC 6946 is 21 billion solar mass units and for IC 342 is 15 billion solar mass units, assuming distances of 10.1 and 4.5 Mpc respectively. Other properties are summarized in the table.

Descriptors:

• *GALAXIES
• *EXTRATERRESTRIAL RADIO WAVES
• HYDROGEN
• MAPS
• RADIO ASTRONOMY
• MAPPING
• ASTRONOMY

Subject Categories:

• Astrophysics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE