High-latitude reflection nebulosities illuminated by the galactic plane

Extended regions of faint nebulosity have been found at high galactic latitudes from a survey in progress with the Palomar 1 .2-m Schmidt telescope. The surface brightness of some of the nebulosities is as high as S B 25 maglL' in V, with many more at fainter levels. Some of the nebulosities are diffuse, while others are filamentary with widths on scales of 30 arcsec that extend in connective patterns over scales of degrees. Photographs of two particulalry bright examples at 1=187', b = -50' and 1=140', b = +40' are given. The second region contains the galaxies M8 1 and M82. Special plates taken in continuum radiation show the regions to be reflection nebulae. Calculations suggest that the source of the illumination at these high latitudes is the flux of the total galactic plane. This flux at any height h above the plane is equivalent to m = - 6.73 visual magnitudes, independent of h. If the same grains that scatter the galactic light also cause the extinction Am of the background objects in the line of sight, then a relation exists between observed surface brightness and Am Eq. (8). Application to the nebulosities in the field near M8 1 and M82 show agreement between the observations and the prediction that the scattered light is from the galactic disc. If true, observations of faint reflection nebulae in the galactic polar regions hold promise to provide new information on the polar extinction.