Filaments

Abstract

I would like to make a brief comment on some work that John Moody, Edwin Turner and I have done on filamentary structure in the Shane-Wirtanen galaxy counts. The picture of the Shane-Wirtanen galaxy counts to the 19th magnitude appears quite filamentary to the eye. The existence of such filaments is quite important theoretically, since filaments could easily be Zeldovich pancakes seen edge-on, and filamentary structure is expected in general when the perturbation spectrum is cut off at small scales. So if the filaments are real, they are telling us something quite important about the universe. The experience of the Martian “canals” reminds us, however, that the eye is very good at picking linear features in random data, and here we are dealing with a clumpy distribution where such effects may be enhanced.