An Accurate Galactic N H Map of the North Ecliptic Pole
Abstract
The Galactic HI column density was measured at 21 min angular resolution over an 8 deg x 9 deg region centered on the north ecliptic pole. Over the region NH varies smoothly between 3 x 1020 atoms/sq cm and 8 x 1020 atoms/sq cm; some structure is seen over most of the map on an 0.5 - 1 deg scale. There are other possible sources of interstellar opacity in this direction which may add an equivalent 1020/sq cm of HI. We evaluate the effect of uncertainties in the HI column density on implied X-ray fluxes of extragalactic objects.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- December 1994
- DOI:
- 10.1086/192105
- Bibcode:
- 1994ApJS...95..413E
- Keywords:
-
- Astronomical Maps;
- Galactic Structure;
- H I Regions;
- Interstellar Matter;
- Line Spectra;
- Molecular Clouds;
- Radio Astronomy;
- Radio Spectra;
- Abundance;
- Astronomical Spectroscopy;
- Ecliptic;
- Hydrogen;
- Astronomy;
- GALAXY: STRUCTURE;
- X-RAYS: GENERAL;
- ISM: ABUNDANCES;
- RADIO LINES: ISM