StarWatch 2.0: RFI filter for SETI signals

We extend our system for radio astronomical monitoring by a cross-validation filter, separating near Earth radio frequency interference (RFI) from deep space signals. The filter searches for similar signals in a nearby frequency band, coming from a different spatial direction than the tested signal. The filter passes the signals which do not have such duplicates. We apply this technique to a database of SETI Institute (setilive.org), containing 1.5 millions of sky observations in a frequency range 0.5-11.2~GHz, where our primary selection identified 28 strong signals possessing extraterrestrial (ET) signature. Cross-validation allows to filter out 24 of those signals as satellite RFI. We present parameters for the remaining 4 signals and discuss statistical significance of these findings.