Upper limits to the H I content of the dwarf spheroidal galaxies.
Abstract
A search for 21-cm H I emission from the six dwarf spheroidal satellites of the Galaxy is described which was performed using a 91-m telescope with a sensitivity of 0.8 Jy/K and a beamwidth of 10 arcmin as well as a 43-m telescope with a sensitivity of 3.7 Jy/K and a beamwidth of 22 arcmin. The galaxies observed include Draco, Ursa Minor, Sculptor, Fornax, Leo I, and Leo II. None of the galaxies was detected, so upper limits for the H I contents are set, ranging from 68 solar masses in Draco to 11,000 solar masses in Leo II. The total amount of hydrogen lost from each galaxy is estimated on the assumptions that mass loss from evolved stars in the dwarf spheroidals is comparable to that from 1-solar-mass stars in the Galaxy and that this has been a steady process over the past billion years.
- Publication:
-
The Astronomical Journal
- Pub Date:
- April 1978
- DOI:
- 10.1086/112211
- Bibcode:
- 1978AJ.....83..360K
- Keywords:
-
- Galactic Radiation;
- Galactic Structure;
- Hydrogen Clouds;
- Interstellar Gas;
- Galactic Evolution;
- Hydrogen Atoms;
- Microwave Emission;
- Stellar Mass;
- Astrophysics;
- Dwarf Galaxies:Neutral Hydrogen