Central Bureau for Astronomical Telegrams
IAUC 7792: XTE J1550-564; 2001id, 2001ih,, 2001ii; P/2001 Y1
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Circular No. 7792
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
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Phone 617-495-7440/7244/7444 (for emergency use only)
XTE J1550-564
J. Swank, E. Smith, and C. Markwardt, Goddard Space Flight
Center, report: "Rossi X-Ray Timing Explorer observations indicate
that XTE J1550-564 is again at a flux of 50-100 mCrab, which it
reached in 2001 Jan. for about 3 weeks. Since 2001 Oct., the ASM
has indicated intermittent levels of a few ASM counts/s. In a
pointed observation on 2002 Jan. 10.875 UT, the PCA confirmed a
level 60 mCrab, with a very hard spectrum (power-law index 1.4 +/-
0.2, cutoff 30-60 keV), corresponding to a 2-50-keV luminosity of
3 x 10**36 erg/s at 2500 pc. The spectrum includes Fe K-shell line
emission, possibly in a reflection component, and about 10 percent
of the luminosity is in a component attributable to a disk. High-
amplitude fluctuations (33-percent rms) are again present, with
characteristic times of 20-100 s (cf. IAUC 7575). Based on recent
behavior, a full outburst is not likely; nevertheless, additional
RXTE observations are scheduled and coordinated observations at
other wavelengths are encouraged."
C. Bailyn, Yale University, adds: "YALO observations on Jan.
12.319 and 13.337 UT yield V = 18.36 and 18.33, respectively.
These values are near the peak optical flux from the last two
outbursts of this source."
SUPERNOVAE 2001id, 2001ih, AND 2001ii
R. Chornock, W. D. Li, and A. V. Filippenko, University of
California, Berkeley, report that inspection of CCD spectra (range
330-1000 nm), obtained on Jan. 14 UT with the Shane 3-m reflector
at Lick Observatory, reveal that SN 2001id (IAUC 7770) is a normal
type-II supernova; hydrogen Balmer, Na I D, and Fe II lines are
present with P-Cyg profiles. SN 2001ii (IAUC 7776) is a supernova
of type Ic. SN 2001ih (IAUC 7776) is probably a type-IIb
supernova; although the spectrum is somewhat noisy, it is similar
to that of SN 1996cb, about 1-2 months past maximum light (Qiu et
al. 1999, A.J. 117, 736). Well-developed He I lines are present,
as well as an absorption line identified with H-alpha.
COMET P/2001 Y1 (HELIN-LAWRENCE)
Further to IAUC 7790, K. Sarneczky reports that his 300-s
unfiltered CCD images taken on Jan. 11.2 UT show a diffuse, 8" coma
and a faint, narrow, 13" tail in p.a. 283 deg.
(C) Copyright 2002 CBAT
2002 January 15 (7792) Daniel W. E. Green
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