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

Abstract

Synthesis observations of netural hydrogen emission in the two spiral galaxies NGC 6946 and IC 342 are presented. The velocity resolution is 21 km/s 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.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1972
Accession Number
AD0744679

Entities

People

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

Organizations

  • Owens Valley Radio Observatory

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Brightness
  • California
  • Catalogs
  • Depression
  • Emission
  • Flux Density
  • Frequency Shift
  • Hydrogen
  • Images
  • Intervals
  • Military Research
  • Observation
  • Observatories
  • Optical Images
  • Photographs
  • Radiation
  • Stratified Fluids

Fields of Study

  • Physics

Readers

  • Atmospheric Science/Meteorology
  • Materials Science (Mechanical Engineering).
  • Solar Physics