Galactic H alpha emission and the Cosmic Microwave Background
We present observations of Galactic H alpha emission along two declination bands where the South Pole cosmic microwave background experiment reports temperature fluctuations. The high spectral resolution of our Fabry-Perot system allows us to separate the Galactic signal from the much larger local s...
| Main Authors: | , , , , |
|---|---|
| Format: | Text |
| Language: | unknown |
| Published: |
arXiv
1998
|
| Subjects: | |
| Online Access: | https://dx.doi.org/10.48550/arxiv.astro-ph/9809189 https://arxiv.org/abs/astro-ph/9809189 |
| Summary: | We present observations of Galactic H alpha emission along two declination bands where the South Pole cosmic microwave background experiment reports temperature fluctuations. The high spectral resolution of our Fabry-Perot system allows us to separate the Galactic signal from the much larger local sources of H alpha emission, such as the Earth's geocorona. For the two bands (at declination -62 and -63 degrees), we find a total mean emission of about 1 Rayleigh with variations of about 0.3 R. The variations are within the estimated uncertainty of our total intensity determinations. For an ionized gas at T around 10**4 K, this corresponds to a maximum free-free brightness temperature of less than 10 microK at 30 GHz (K-band). Thus, unless there is a hot gas component with T around 10**6 K, our results imply that there is essentially no free-free contamination of the SP91 (Schuster et al. 1993) and SP94 (Gunderson et al.1995) data sets. : 12 LaTex pages, 4 figures, accepted by Astronomy and Astrophysics (submitted 15 may 1998 accepted 24 june 1998) |
|---|