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Date: Mon, 29 Mar 93 22:03:26 PST
From: alex%bkyim.hepnet@Lbl.Gov (ALEX FILIPPENKO, UC BERKELEY, 510-642-1813)
Subject: Probable supernova in M81
3-29-93
Dear Nova and Supernova observers:
The object in M81 is almost certainly a supernova. My colleagues nearly
got a spectrum 20 minutes ago, but Lick got fogged in just as they were
about to start the exposure!! They hope the weather will clear soon.
Below is a message I sent to Brian Marsden and Dan Green not long ago.
If a Type Ia, the SN should rise to about mag 8 or 8.5; if Type II or
Ib/c, it might be somewhat fainter (9.5 or 10). I urge all of you to
observe it as much as possible. This is our best opportunity to observe
a bright supernova in over 20 years (since SN 1972E). Low- or moderate-
resolution spectroscopy with small telescopes during the upcoming bright
run will be invaluable, since most of the larger telescopes will be
equipped with IR equipment or high-dispersion spectrographs. Please
use a narrow slit (roughly 2") for good resolution and a wide slit
(roughly 8") to get good spectrophotometry. Those of you who can should
rotate your narrow slit to the parallactic angle, to preserve the
relative spectrophotometry, especially if you can't take another spectrum
through a wide slit.
Well-sampled light curves (UBVRIJHKLM) will also be needed. I am willing
to act as a coordinator of the ground-based optical spectra and photometry,
so feel free to send me data, questions, etc. All contributors of good data
will be included in subsequent data (plus some interpretation) papers.
Note that we also have an excellent chance to study the ISM in M81 and
the Galaxy with this object. Thus, high-dispersion spectra are welcome.
Moreover, this object could easily be studied with spectro-polarimeters.
Everyone is encouraged to join in on the observations! We should be
able to follow this thing for several years (depending on the type)
with modern equipment.
Cheers,
Alex Filippenko
alex@bkyast.berkeley.edu
42224::alex
510-642-1813 (phone)
510-642-3411 (fax)
****
Brian and Dan,
Here is some information for the IAU Circulars. This thing is jinxed.
We missed it in our recent images of M81 with the Leuschner Observatory
Supernova Search (it was off the field by roughly 10" in each case!).
Now here's another sob story: Just as my colleagues at Lick were about
to get a spectrum (they already had the star on the slit!), the fog rolled
in!! Even 1 minute would have given a spectral type. They think it will
clear up later on... Let's hope so. But for now, here's all I have.
Note that our approximate position (about 45" W and 160" S of the
nucleus) is way off from the 210" W, 200" S that is floating around
through the nova network. This cost the Palomar 5-m infrared observers
a lot of time --- and now they are fogged in, too.
Aaaargh!
Alex Filippenko
SUPERNOVA 1993xxx IN M81 (CHECK NAME!!)
(Discovery information...)
A. V. Filippenko, University of California at Berkeley, reports
that a CCD image of M81 obtained on March 30.1 UT by R. R. Treffers
and Y. Paik (also of Berkeley) with the 0.8-m reflector at Leuschner
Observatory confirms the presence of a new stellar object roughly
45" W and 160" S of the nucleus.
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