The Low-Resolution DRAO Survey of H I Emission from the Galactic Plane. II.
Abstract
In 2000, a survey of H I line emission in the Galactic plane between Galactic longitudes l=72.2d and 149.0d, covering latitudes from b=-5.4d to 7.2d, made using the 26 m telescope at the Dominion Radio Astrophysical Observatory, was published as part of the Canadian Galactic Plane Survey project. The survey with the 26 m telescope has now been extended to cover longitudes from l=50.0d to 195.0d, between the same latitude limits. In addition, a region at higher Galactic latitudes (b=7.4d-24.0d) has been surveyed between longitudes l=96.4d and 120.2d. As in the initial survey, spectra were observed at 0.2d intervals of longitude and latitude (0.33 half-power beamwidths). (In an appendix, it is demonstrated that, when single-antenna data and interferometer data are to be combined, the single-antenna data must be sampled at an interval no greater than 0.5 times the half-power beamwidth of the single antenna. Coarser sampling will result in the introduction of spurious structure into the resulting images.) The spectral resolution is 1.32 km s-1, and the LSR velocity range is -260-161 km s-1. The spectra have been corrected for stray radiation and have an estimated Tb scaling accuracy of 1% and an estimated rms noise in one channel (0.8245 km s-1) of 0.25 K. Regions of suspected strong H I self-absorption have been identified using a statistic characterizing the ``complexity'' of the observed spectra. Comparison with spectra from the Leiden/Dwingeloo Survey supports the conclusion from our earlier paper that a small percentage (~1%-2%) of the spectra in the latter survey suffer from calibration errors exceeding 10%. A table of positions of the more discordant spectra is given.
- Publication:
-
The Astronomical Journal
- Pub Date:
- June 2005
- DOI:
- 10.1086/430213
- Bibcode:
- 2005AJ....129.2750H
- Keywords:
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- Galaxy: Kinematics and Dynamics;
- ISM: Atoms;
- Radio Lines: ISM;
- Surveys