Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 7729: 2001es; N IN M31; Cyg X-1

The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).

Read IAUC 7728  SEARCH Read IAUC 7730

View IAUC 7729 in .dvi or .ps format.
IAUC number

                                                  Circular No. 7729
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)

     W. D. Li, University of California at Berkeley, reports the
discovery by LOTOSS (cf. IAUC 7514) of an apparent supernova (mag
about 18.0) in unfiltered images taken with the Katzman Automatic
Imaging Telescope (KAIT) on Oct. 7.4 and 8.4 UT.  SN 2001es is
located at R.A. = 2h02m08s.27, Decl. = +19o05'27".5 (equinox
2000.0), which is 0".8 west and 2".5 north of the nucleus of a
galaxy that is itself located about 150" west and 84" north of the
nucleus of UGC 1518.  A KAIT image of the same field taken on Sept.
27.4 showed nothing at this position (limiting mag about 19.0).

     Li also reports the discovery of an apparent nova in M31 on
unfiltered KAIT images taken on Oct. 5.4 (mag about 17.5) and 6.4
UT (mag about 16.9).  The nova is located at R.A. = 0h43m03s.30,
Decl. = +41o12'11".3 (equinox 2000.0), which is about 213" east and
238" south of the nucleus of M31 (= NGC 224).  A KAIT image taken
on Oct. 1.4 showed nothing at this position (limiting mag about

     G. Pooley, Cavendish Laboratory, University of Cambridge,
communicates:  "Recent observations of Cygnus X-1 with the Ryle
Telescope show unusually low radio emission, with a mean flux
density of about 0.95 mJy at 15 GHz over the period Oct. 1-9.  For
the past five years, the source has usually been in a low/hard
x-ray state, with radio emission always present at the level 5-40
mJy.  The current lack of radio emission corresponds to a
transition to the high/soft x-ray state, as seen in the publicly
available RXTE monitoring data."
     M. P. Rupen, A. J. Mioduszewski, and V. Dhawan, National Radio
Astronomy Observatory, further report:  "Observations with the Very
Large Array on Oct. 3 confirm the Ryle results noted above, putting
even lower limits on the radio flux density, with no detections to
rms noise levels of 0.58, 0.17, 0.12, and 0.34 mJy/beam at 1.425,
4.860, 8.460, and 14.939 GHz, respectively.   Further observations
of this unusual radio/x-ray state at other wavelengths are strongly

                      (C) Copyright 2001 CBAT
2001 October 8                 (7729)            Daniel W. E. Green

Read IAUC 7728  SEARCH Read IAUC 7730

View IAUC 7729 in .dvi or .ps format.

Our Web policy. Index to the CBAT/MPC/ICQ pages.

Valid HTML 4.01!