A Multifrequency Blazar catalog (Roma-BZCAT)

We present a general catalog of blazars based on an extensive review of literature data from multi-frequency surveys. Blazars are distinguished in BL Lacertae objects. Flat spectrum radio Quasars and Blazars of uncertain/transitional type. Each object is identified by a root name, coded as BZB, BZQ and BZU for the three subclasses respectively, and by its J2000 coordinates. This catalog is being built as a tool useful for the identification of the extragalactic sources that will be detected by the GLAST LAT experiment. An electronic version is available from the ASI Science Data Center web site. The list presently includes objects between R.A.= 0h and R.A.= 12h; the full sky is expected to be available by the end of 2007, approximately when GLAST will be fully operational.