A Snowden is a unit of soft X-ray emissivity, equivalent to ROSAT counts .[1] These units were chosen by S. L. Snowden when working with the ROSAT mission to create the ROSAT All-Sky Survey in order to make the surface brightness values fit into a two byte integer.
References
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.