AAVSO: Special Notice #8


The optical afterglow and underlying supernova for GRB060218
continues to brighten and has generated a lot of interest in the
scientific community. It is well positioned in the early evening
sky for professional and amateur monitoring. The latest
coordinates are:

R.A.: 03:21:39.71 Decl.: +16:52:02.1 J2000

Please observe with CCD V or Rc filters, and use long enough
exposures to be able to reach S/N=50 on the object, which should
be around V=16-19. Note that unfiltered observations are not
very useful for GRB afterglows, which usually require the
combination of observations from many different sources.

Rapid time series is not necessary, but if you can get multiple
images in a single filter with S/N=50, or a V/R pair per night,
that won't hurt.

A finding chart has been posted at this URL:

http://www.aavso.org/observing/programs/hen/grb060218.png

Field photometry will be posted to the AAVSO High Energy
Network and AAVSO Photometry discussion groups when it becomes
available.

The burst, which occurred at 03:34:30.97UT on 060218, was
detected by the Swift satellite. The optical afterglow was
discovered by its UVOT instrument (GCN 4775). Neil Gehrels
pointed out in GCN 4787 that this burst was a very unusual
event. The X-ray light curve can be seen at:
http://www.merate.mi.astro.it/~moretti/lc_060218.gif

Mirabal and collaborators (GCN 4792) measured a red shift of
z=0.0331, making it a very nearby GRB.  A host galaxy can be
seen on SDSS images. Soderberg and collaborators (GCN 4794)
report that there was an immediate detection of a radio source.

Probably most importantly, Masetti and collaborators (GCN 4803)
report that a supernova spectrum was emerging only 3 days after
the burst.

Most researchers now believe that the supernova (designated SN
2006aj, see IAUC 8674) is still rising to maximum.  It is
currently about 19th magnitude, but should increase to V=16-17
in the next week or two, well within the range of AAVSO
observers.

In GCN 4777, Cool et al. indicate that images, photometry and
astrometry are available at:
http://mizar.as.arizona.edu/~grb/public/GRB060218


This special notice was compiled by: A. Henden & A. Price
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