Central Bureau for Astronomical Telegrams
IAUC 8042: 2003B NEAR NGC 1097; 2003A
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Circular No. 8042
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 2003B NEAR NGC 1097
R. Evans, Hazelbrook, N.S.W., reports his visual discovery of
an apparent supernova (mag about 15.0) on Jan. 5.5 UT with a 0.41-m
reflector at Frogrock, near Mudgee, N.S.W. Evans estimates the new
object to be 90" west and 175" north of the nucleus of NGC 1097
(R.A. = 2h46m.3, Decl. = -30o17', equinox 2000.0) in a faint
emission region visible on the European Southern Observatory B
Survey image (and he adds that SN 2003B is also located 40" due
east of the nearby small elliptical galaxy NGC 1097A); no star is
seen at this location on either the ESO B or J Survey. The new
object was confirmed visually by S. Quirk.
R. Kirshner and J. Silverman, Harvard-Smithsonian Center for
Astrophysics, obtained a spectrogram (range 400-900 nm) of SN 2003B
on Jan. 6.17 UT with the Clay 6.5-m telescope at Las Campanas
Observatory. The spectrum resembles that of a type-II supernova, <
2 weeks past maximum. A well-developed P-Cyg line at H-alpha has a
peak near the systemic velocity of NGC 1097, which is marked by a
narrow emission, presumably due to the H II region near the event.
The deepest absorption of the P-Cyg line at H-alpha is shifted
about 6300 km/s toward the blue.
A. V. Filippenko and R. Chornock, University of California,
Berkeley, write: "Inspection of CCD spectra (range 310-1000 nm)
obtained on Jan. 6 UT with the Keck I 10-m telescope (+ LRIS) shows
that SN 2003B is of type II, a few weeks past the explosion.
H-alpha exhibits a well-developed P-Cyg profile, with an absorption
minimum corresponding to an expansion velocity of 7000 km/s
(assuming the NED redshift of NGC 1097, 1275 km/s). The expansion
velocity measured from H-beta is 5600 km/s. Many Fe II and other
absorption lines are also visible. From our data, it is not
possible to determine whether the supernova is in NGC 1097 or
1097A, whose redshifts are nearly identical."
SUPERNOVA 2003A IN UGC 5904
Filippenko and Chornock also report that inspection of CCD
spectra, obtained as above on Jan. 6 UT, shows that SN 2003A (IAUC
8041) is of type Ib/c, probably a few weeks after maximum
brightness. Weak He I absorption lines are visible, but the
overall spectrum resembles that of type-Ic supernovae. The
redshift derived from a superposed H II region is about 7000 km/s.
The supernova is probably a member of the southern spiral galaxy in
the interacting pair UGC 5904, even though it appears projected
closer to the nucleus of the northern elliptical galaxy.
(C) Copyright 2003 CBAT
2003 January 6 (8042) Daniel W. E. Green
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