What is the var_flg? "The probability is computed for a band only when there are at least 11 individual exposure measurements available. A value of "0" in a band indicates insufficient or inadequate data to make a determination of possible variability. Values of "1" through "9" indicate increasing probabilities of variation. Values of "1" through "4" are most likely not variables. Sources with values of "5" through "7" are likely flux variables, but are the most susceptible to false-positive variability. Var_flg values greater than "7" have the highest probability of being true flux variables in a band."
All sources (both point sources and extended) where var_flg had a value of 9 in any of the four bands were downloaded and these were cross referenced against the International Variable Star Index (VSX) using a search radius of 20 arc seconds. Of the 50081 entries 6835 were known variable stars within 20 arc sec of a VSX entry.
| Distance between WISE and VSX variable star result (arcsec) | Number of entries |
| 0 - 1 arcsec | 3450 (50.5%) |
| 1 - 2 arc sec | 912 (13.3%) |
| 2 - 3 arc sec | 548 (8.0%) |
| 3- 5 arc sec | 891 (13.0%) |
| 5 - 10 arc sec | 883 (12.9%) |
| 10 - 20 arc sec | 151 (2.2%) |
| Point Source | Not point source | |
| VSX variable star | 5726 | 1109 |
| Unidentified variable | 37923 | 5323 |
| Percentage identified | 15% | 21% |
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| Random sample of 32000 WISE objects |
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32000 of the unidentified variable objects |
All the identified VSX variable stars |
Spreadsheet 1 - variable WISE point-source objects also listed in VSX
Spreadsheet 2 - variable WISE non point-source objects also listed in VSX
Spreadsheet 3 - variable WISE point-source objects not listed in VSX
Spreadsheet 4 - variableWISE non point-source objects not listed in VSX
Over the last few years I have carried out many astronomical data mining or data analysis projects. Most remain unpublished and this series of papers aims to put them all into the public domain. I welcome constructive feedback from readers and encourage colleagues to take the work forward, perhaps as far as peer reviewed publication. I can be contacted by email. and this address is monitored daily.
Martin Piers Nicholson - Shropshire, United Kingdom.
This page was last updated on July 15th 2011.
