Planetary nebulae in Local Group galaxies. IX. Velocity modulated photographs of the center of M31.
Abstract
A sequence of velocity-modulated photographs made with a camera consisting of a temperature-tuned, 2.1 A (FWHM) O III forbidden line 5007 A interference filter, a two-stage cooled image intensifier, and a calibrating photomultiplier, was used to find and measure the radial velocities of 42 faint planetary nebulae in the center of M31. Of the 42, 19 are new identifications. After deriving a planetary-to-luminosity ratio (PLR) value of 69 + or - 9 for the luminosity corresponding to an integrated blue magnitude of 8.37, the PLR is combined with M31's integrated magnitude to estimate that there are approximately 2800 + or - 350 nebulae in the first 3 mag of M31's luminosity function, and 21,000 planetary nebulae within 8 mag of the brightest nebulae.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1982
- DOI:
- Bibcode:
- 1982ApJ...256..120L
- Keywords:
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- Andromeda Galaxy;
- Astronomical Photography;
- Galactic Clusters;
- Galactic Structure;
- Local Group (Astronomy);
- Planetary Nebulae;
- Radial Velocity;
- Velocity Modulation;
- Brightness;
- Interstellar Extinction;
- Luminosity;
- Magellanic Clouds;
- Star Distribution;
- Stellar Evolution;
- Astronomy