Possibilities of Using Middle-Band Filters to Search for Polar Candidates

Abstract

We present a method for searching for polar candidates using mid-band filters. One of the spectral singularities of polars is the $HeII\lambda 4686$Å~ strong emission line. We selected the Edmund Optics filters with central wavelengths of 470, 540, and 656 nm and a transmission bandwidth of 10 nm. These filters cover the regions of the $HeII\lambda 4686$Å~ line, continuum, and the $H_{\alpha }$ line respectively. We constructed a color diagram based on the available spectra of polars and objects with a zero redshift from the SDSS archive. We show that most polars make a group with unique color indices. In practice, the method is implemented in SAO RAS at the Zeiss-1000 telescope with a new multi-mode photometer-polarimeter (MMPP). Approbation of the method with the known polars allowed us to develop two criteria to select candidates with an efficiency of up to 75\%.

10 pages, 5 figures, 2 tables