[vsnet-chat 1625] Re: FASTT-2 variables

[aah@nofs.navy.mil]

I've uploaded several .gif files to 
  http://ftp.nofs.navy.mil/pub/outgoing/aah/fastt1
of photometry on some of the FASTT-1 variables performed
by the GEA group in Spain.  Of the several dozen FASTT
variable candidates that they have observed, all show
variation; so maybe the list is as clean as I had hoped!
  Another example of the raw FASTT data quality is
given in figure 3 of the paper (henden.fig3.ps?), comparing
FASTT photometry to published R-band values for 3 variables.
  As for the number of variables waiting to be discovered:
the FASTT-1 survey found that only 5 percent of its variables
were known GCVS entries.  Since I put *very* stringent
restrictions on stars before they appeared in the main list,
only 0.24percent of all stars in the 16 SDSS zones (about
300 square degrees) were included; the usual results from
other surveys indicate that 1-2 percent of all stars are
easily found to be variable by simple CCD surveys.  If you
can go deep enough to reach all of the GSC stars (say, V=14.5),
then you should find 100-200K variables, with most of them
unknown.  As Brian said, ROTSE/LOTIS/BOOTES/LONEOS/etc.
all should have thousands of variables in their databases.
As Dan said, most of these will be unimportant to the visual
observer because they will be low amplitude.  I'm hoping
enough of them will be the fun guys -- CVs, double mode
pulsators, etc. -- to keep me happy for a while!
  BTW, the problem with most of the all-sky surveys currently
underway is that they are confusion-limited in the Milky Way
(big pixels).  They are also unfiltered, which means you
can discover variables, but the photometry is difficult to
use when comparing to other sources.  The TASS Mark III/IV
cameras are better in this regard since they use standard
filters (V&I).
Arne

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