Allsky search of EXPLORER data

Allsky search of EXPLORER data




Bulletin No.2, 30th November, 2001




Kazik Borkowski started to write a web site for our all-sky search. Please visit it and send him your comments and suggestions.

There were a few breakdowns of the PCs during past month but they were quickly fixed.

I am trying to involve in our search some PCs that were recently acquired by my Institute. These are Pentium III 800MHz and there are four of them. I've installed our software and I hope to run our codes during the nights on those PCs.

I should mention that we are also running the codes on our computers at home. When we were away our sons Piotr (14 years old) and Szymon (15 years ald) were supervising the search. Let's thank them! My son finds that he can play COMMANDOS 2:Men of Courage (TM) while our code runs. So multitasking in Windows works!

I started to test the new version of the codes to verify the candidates. The verification procedure consists of several steps:

  • 1.Transformation from the linear parameters to astrophysical parameters: frequency, spin-down, declination, right ascension.
  • 2.Search over a small grid in astrophysical parameters followed by fine search using Nelder-Mead algorithm.
  • 3.Search over a small grid in astrophysical parameters in different 2-day stretch of data that does not overlap with the original one and the fine search.
  • 4.Search over a small grid in astrophysical parameters in a 4-day stretch of data that includes the 2-day original data and the fine search.

    The reults for our candidates of highest signal-to-noise ratio equal to 7.9 are as follows.

    For astrophysical parameters I get a signal-to-noise equal to 8.17 (2.5% false alarm probability). Very high but still lower than our threshold of 8.3 corresponding to 1% false alarm. There is no signal for different stretch of data (step 3 above). There is an event of low signal-to-noise of 6.86 for 4-day stretch of data (step 4 above) but its declination is markedly different from declination in the original 2-day data.

    So as far as I can tell this is not a real candidate. 

    

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|__________________________________________|

|         SEARCH PROGRESS REPORT           | 

|------------------------------------------|

|                                          |

|Percentage of the Northern Sky searched:  | 

|                                          |

|                                          |

|                 42.2%                    |

|                                          |

|                                          |

|Highest signal-to-noise of a candidate:   |

|                                          |

|                                          |

|                  7.9                     |

|                                          |

|__________________________________________|

    Keep on searching!

    All the best,

    Andrzej