Central Bureau for Astronomical Telegrams
IAUC 7795: 2001ij, 2001ik, 2001il, 2001im, 2001in; XTE J1550-564
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Circular No. 7795
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVAE 2001ij, 2001ik, 2001il, 2001im, 2001in
A. V. Filippenko and R. Chornock, University of California,
Berkeley, report on inspection of CCD spectra (range 330-1000 nm),
obtained on Jan. 17 UT with the Keck-I telescope, of the supernovae
reported on IAUC 7778: "SN 2001ij is of type II-P at redshift
0.038, with hydrogen Balmer and Fe II lines having P-Cyg profiles;
the object is still relatively bright. SN 2001ik is probably a
supernova at redshift 0.094; some broad undulations appear to be
present in its spectrum, which is heavily contaminated by light
from the host galaxy. SN 2001il is of type Ia, roughly 2 months
past maximum brightness, at redshift 0.208. SN 2001im, at redshift
0.075, may be of type IIb; He I lines appear to be present, along
with H-alpha absorption, but the spectrum is too noisy for
definitive classification. The putative host of SN 2001in is at
redshift 0.218, but the supernova is projected quite far from it.
Moreover, the spectrum of SN 2001in more closely resembles that of
a type-Ia supernova at redshift approximately 0.35. Accurate color
measurements near the time of discovery should help resolve this
discrepancy. The redshifts of the host galaxies are measured from
narrow emission lines."
XTE J1550-564
S. Corbel, Universite Paris 7 and CEA, Saclay; R. Fender,
University of Amsterdam; and A. Tzioumis, Australia Telescope
National Facility, report that Australia Telescope Compact Array
radio observations of XTE J1550-564, obtained on Jan. 17, confirm
the reappearance of radio emission associated with the recent
reactivation in x-rays (IAUC 7792), with flux densities of 2.4 +/-
0.1 and 2.5 +/- 0.1 mJy at 4.8 and 8.6 GHz, respectively. They
add: "This flat spectrum is as expected for a self-absorbed jet
in the low/hard x-ray state. We see also an unexpected additional
radio source, located at R.A. = 15h50m55s.97, Decl. = -56o28'33".5
(equinox 2000.0; uncertainty < 1"), > 20" west of the x-ray binary,
with preliminary flux densities of 4.2 +/- 0.1 mJy at 4.8 GHz and
2.4 +/- 0.1 mJy at 8.6 GHz -- consistent with an optically thin
synchrotron spectrum. Systematic uncertainties in the flux
densities of both sources may be larger than the formal errors, due
to the proximity of a bright supernova remnant. The new source was
not visible in images of the field in June 2000 or Feb. 2001, to a
limit of 0.27 mJy (3 sigma) at 8.6 GHz, so it is transient;
although the angular separation between it and XTE J1550-564 is
large, we cannot rule out an association with the x-ray binary,
although it may be an unrelated field source in coincidental
outburst, in which case it may be affecting the x-ray data."
(C) Copyright 2002 CBAT
2002 January 19 (7795) Daniel W. E. Green
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