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IAUC 6422: 1996ai; QX Nor

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                                                  Circular No. 6422
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
Phone 617-495-7244/7440/7444 (for emergency use only)

SUPERNOVA 1996ai IN NGC 5005
     Claudio Bottari, Sava, Italy, reports his discovery on a CCD
image (+ ISIS deep-sky filter) obtained on June 16.86 UT of a
supernova of mag 14.5 located some 50" east-northeast of the center
of NGC 5005.  S. Nakano, Sumoto, Japan, relays a subsequent
unfiltered CCD observation by R. and Y. Kushida (Yatsugatake South
Base Observatory) on June 19.472, which confirms the presence of a
new star of mag 13.0 (near an apparent H II clump) that was not
present on a May 12 image (limiting mag 16.5), located at R.A. =
13h10m58s.13, Decl. = +37o03'35".4 (equinox 2000.0).
     P. Garnavich, P. Challis, and R. Kirshner, Center for
Astrophysics, communicate: "Spectra obtained by P. Challis with the
Multiple Mirror Telescope and by P. Berlind with the 1.5-m
Tillinghast telescope on June 20.3 UT show a red continuum with a
strong, broad absorption feature at 614.81 nm.  The spectra suggest
that SN 1996ai is an extremely obscured type-Ia supernova, a few
days before maximum light.  A deep Na I interstellar absorption
line is observed at 591.4 nm with an equivalent width of 0.23 nm.
The steep red continuum implies E(B-V) > 1.0 when compared with SN
1996X at a similar phase.  CCD images taken with the Whipple
Observatory 1.2-m telescope by J. Kleyna on June 20.3 show the
supernova 24" east and 4" north of the galaxy nucleus at V = 16.2
+/- 0.2."

     S. Wachter, E. W. Deutsch, J. D. Hughes, and B. Margon,
University of Washington; and A. Layden, McMaster University,
report: "Observations made with the Cerro Tololo 0.9-m telescope of
the transient x-ray source 4U 1608-52 since the recent x-ray
outburst (IAUC 6331, 6336) show that the faint optical counterpart
QX Nor (Grindlay and Liller 1978, Ap.J. 220, L127) has reappeared.
Data obtained in May and June show the object at I = 20, about 2
mag fainter than during the 1977 appearance.  However, these recent
observations are 2-3 months after the x-ray outburst, whereas the
1977 counterpart was observed only 1 month later; thus a similar
maximum optical brightness at both x-ray outbursts is plausible.
Even the faint current state is probably still significantly
brighter than the true quiescent magnitude of the counterpart,
which has not yet been established: a comparison of R images of the
field obtained this year with identical data last year, when there
is no optical detection (and presumably no x-ray activity), shows
that the object has brightened by at least 2 mag in that 1-yr
interval.  A search for short-term variability in about 10 nights
of data is underway."

                      (C) Copyright 1996 CBAT
1996 June 20                   (6422)            Daniel W. E. Green

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