Central Bureau for Astronomical Telegrams
IAUC 7868: XTE J1118+480; 2002bs, 2002bv, 2002bx
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Circular No. 7868
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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XTE J1118+480
C. Zurita, J. Casares, and I. G. Martinez-Pais, Instituto de
Astrofisica de Canarias; and A. Piccioni, S. Bernabei, C. Bartolini,
and A. Guarnieri, Bologna University and Bologna Astronomical
Observatory, report: "New R-band CCD images of the halo blackhole
x-ray transient XTE J1118+480 (IAUC 7389, 7390) have been obtained
on Feb. 5 with the 2.5-m NOT telescope (Observatorio del Roque de
los Muchachos), on Feb. 22-24 with the 1-m OGS telescope
(Observatorio del Teide), and on Mar. 19 with the 1.52-m telescope
at Loiano (Osservatorio di Bologna). The system has declined 0.28
mag from its previous reported value (Zurita et al. 2002,
http://xxx.lanl.gov/abs/astro-ph/?0202438) to an average magnitude
R = 18.93 +/- 0.01. The current magnitude is consistent with pre-
outburst estimates (op.cit.), indicating that the transient has
probably reached true quiescence. Lightcurves are dominated by a
classical ellipsoidal modulation with night-to-night variations
that may be caused by residual superhump contribution (IAUC 7617).
The ellipsoidal modulation shows a peak-to-peak amplitude of about
0.26 mag (i.e., about 0.08 mag larger than previous determinations;
Zurita et al., op.cit.), as expected by the relative drop in
accretion disk brightness."
SUPERNOVAE 2002bs, 2002bv, 2002bx
T. Matheson, S. Jha, P. Challis, and R. Kirshner, Harvard-
Smithsonian Center for Astrophysics, report on spectra (range
370-750 nm) obtained by M. Calkins with the Mt. Hopkins 1.5-m
telescope (+ FAST spectrograph). A spectrum of SN 2002bs (cf. IAUC
7861), obtained on Apr. 3.32 UT, confirms it to be a type-Ia
supernova; adopting the NASA/IPAC Extragalactic Database (NED)
recession velocity of 2895 km/s for the host galaxy, the supernova
expansion velocity is about 9500 km/s for Si II (rest 635.5 nm).
The spectral-feature age of SN 2002bs (Riess et al. 1997, A.J. 114,
722) is 8 +/- 2 days after maximum. A spectrum of SN 2002bx (cf.
IAUC 7864), obtained on Apr. 3.15, shows it to be a type-II
supernova before maximum; the spectrum consists of a very blue
continuum with P-Cyg lines of hydrogen and helium. Adopting the
NED recession velocity of 2260 km/s for the host galaxy (IC 2461),
the expansion velocity derived from the minimum of the H-beta line
is 11 600 km/s. A spectrum of SN 2002bv (cf. IAUC 7864), obtained
on Apr. 3.13, shows it to be a type-IIn supernova; the spectrum
consists of a blue continuum with hydrogen lines consisting of
broad (FWZI about 5400 km/s) and narrow (FWHM about 350 km/s)
components.
(C) Copyright 2002 CBAT
2002 April 4 (7868) Daniel W. E. Green
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