Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 7266: V4334 Sgr; GRS 1758-258; C/1999 H1

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 7265 SEARCH Read IAUC 7267

View IAUC 7266 in .dvi or .ps format.
IAUC number 

                                                  Circular No. 7266
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)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)


V4334 SAGITTARII
     K. Hinkle and R. Joyce, Kitt Peak National Observatory (KPNO),
report infrared photometry of V4334 Sgr (cf. IAUC 6322) obtained on
two different instruments (TIFKAM on Sept. 1, observers Joyce and
A. Koekemoer; and the Phoenix spectrograph in imaging mode with
narrow-band filters on the other nights, observers Hinkle, C.
Kulesa, and J. Melendez) at the KPNO 2.1-m telescope:  Sept. 1.15
UT, J = 13.3, H = 9.9, K = 7.2; 18.09, [2230 nm] = 6.9; 19.10,
[1558 nm] = 10.5; 19.11, [1282 nm] = 13.0; 27.09, [3226 nm] = 4.2;
28.08, [4651 nm] = 2.5.  The photometry has an accuracy of better
than 0.2 mag.  V4334 Sgr is fainter at K than in April (cf. IAUC
7155) and has become redder.  The infrared photometry is consistent
with a 740-K blackbody.


GRS 1758-258
     D. M. Smith, University of California, Berkeley; W. A. Heindl,
University of California, San Diego; and J. H. Swank, Goddard Space
Flight Center, write:  "Weekly RXTE PCA monitoring of blackhole
candidate GRS 1758-258 shows that this persistent source, which has
been in a hard state since at least the beginning of 1996, has
since 1999 Feb. 19 entered a period of oscillation between hard
(power-law index 1.4-1.7, thermal disk component undetectable or <
10 percent of the 2-10-keV luminosity) and soft (index 2.0-2.3,
thermal disk > 20 percent) states.  The first cycles had only minor
spectral changes and a 1-month timescale.  The changes have become
gradually more extreme, and, since Sept. 12, have begun to occur on
scales < 1 week.  The state changes may modulate mass loss to the
radio jets.  Observations in the x-ray and infrared-to-radio bands
are strongly encouraged, frequent monitoring in particular."


COMET C/1999 H1 (LEE)
     Extension to ephemeris on IAUC 7251 (elements MPC 35814):

1999 TT     R. A. (2000) Decl.   Delta     r    Elong. Phase    m1
Sept.29     1 29.80   +55 19.3   0.828   1.625  125.0   30.3    8.7
Oct.  4     0 32.25   +49 27.6   0.837   1.697  134.6   24.8    8.9
      9    23 50.62   +42 22.5   0.877   1.768  140.8   20.9    9.2
     14    23 21.83   +35 16.0   0.944   1.838  142.4   19.3    9.5
     19    23 02.06   +28 50.9   1.036   1.908  139.8   19.7    9.9

                      (C) Copyright 1999 CBAT
1999 September 29              (7266)            Daniel W. E. Green

Read IAUC 7265 SEARCH Read IAUC 7267

View IAUC 7266 in .dvi or .ps format.

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

Valid HTML 4.01!