Central Bureau for Astronomical Telegrams
IAUC 6094: 1994ab, 1994ac; GRS 1915+105 AND X-RAY N IN Sco
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Circular No. 6094
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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 TWX 710-320-6842 ASTROGRAM CAM
MARSDEN@CFA.HARVARD.EDU or GREEN@CFA.HARVARD.EDU (science)
SUPERNOVAE 1994ab, 1994ac
T. Matheson and A. V. Filippenko, University of California at
Berkeley, report that preliminary inspection of an uncalibrated CCD
spectrogram (range 420-700 nm, resolution 0.7 nm), obtained on Oct.
11 with the 3-m Shane reflector at Lick Observatory, suggests that
SN 1994ab (IAUC 6089) is of type Ia, roughly 1-2 months past maximum,
with a recession velocity of 10500 km/s. SN 1994ac (ibid.) is of
type II, dominated by H-alpha emission, with a recession velocity
of 5300 km/s.
GRS 1915+105 AND X-RAY NOVA IN SCORPIUS
F. Nagase, H. Inoue, T. Kotani, and Y. Ueda, on behalf of the
ASCA Team, communicate: "We observed the two x-ray novae GRS
1915+105 and GRO J1655-40 with ASCA on Sept. 27-28, with exposure
times of 20000 s each. Both sources were bright in the ASCA soft
x-ray band during the observations. Preliminary analyses reveal
that the superluminal x-ray transient source GRS 1915+105, which
was observed during Sept. 27.03-27.54 UT, showed an intensity
variation that was small within +/-10 percent of the average flux
over time scales from minutes to hours. The average flux in the
range 2-10 keV was 1.0 x 10E-8 erg cmE-2 sE-1 (or about 500 mCrab).
The GIS and SIS spectra in the range 1-10 keV can be roughly
represented by a power-law model with a photon index of about 2.2
and an absorption column density of 4.3 x 10E22 cmE-2, with
significant spectral softening at high energy. A weak edge-like
structure is visible around 7 keV; however, no conspicuous lines
are seen in the spectra.
The x-ray nova in Scorpius (GRO J1655-40) was again observed
with ASCA during Sept. 27.54-28.18. The intensity variation was
small during the observation (< +/-20 percent), in contrast with
the large intensity variation in the previous observation on Aug.
23 (IAUC 6063). The average flux in the range 2-10 keV was 7.7 x
10E-9 erg cmE-2 sE-1 (or about 400 mCrab). The GIS and SIS spectra
in the range 1-10 keV can be roughly represented by a power-law
spectrum with a photon index of about 2.0 and an interstellar
absorption column density of 4.4 x 10E21 cmE-2, with significant
spectral softening at high energy. A weak but significant
structure is seen around 6-7 keV."
1994 October 12 (6094) Daniel W. E. Green
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