Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 6519: C/1995 O1; XTE J1856+053 AND GRO J1849-03

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 6518  SEARCH Read IAUC 6520

View IAUC 6519 in .dvi or .ps format.
IAUC number

                                                  Circular No. 6519
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
Phone 617-495-7244/7440/7444 (for emergency use only)

     C. M. Wright, Max-Planck-Institut fur Extraterrestrische Physik;
and C. H. Smith and T. Fujiyoshi, University College, Australian Defence
Force Academy, report observations on Aug. 2.5 and 3.4 UT with the
Anglo-Australian Telescope and the mid-infrared camera NIMPOL.
Although conditions were not photometric, estimated fluxes in a
5"-diameter aperture on Aug. 2.5 at 8.5, 11.5 and 12.5 microns
(1-micron-wide filters) were (in units of 10**-18 W cm-2 micron**-1),
4.4 +/- 0.2, 11.7 +/- 0.1 and 11.7 +/- 0.2, respectively.  Quoted
uncertainties are purely statistical, whilst absolute calibration is
approximately 30 percent.  The 8.5-12.5-micron color temperature is
187 +/- 10 K, well above the 147 K expected from a blackbody in
radiative equilibrium at 3.57 AU from the sun.  The silicate feature,
as judged from the 11.5-micron data, is a factor of 1.1 +/- 0.2 above
the 187-K continuum.  On Aug. 3.4 the 11.5-micron flux in a 5"-diameter
aperture was (in units as before) 6.6 +/- 0.1, suggesting that the comet
faded by at least 15 percent between the observations."

    Naked-eye magnitude estimates: Dec. 2.06 UT, 4.1 (A. Hale, Cloudcroft,
NM); 3.69, 3.8 (K. Hornoch, Lelekovice, Czech Republic); 4.06, 4.0 (Hale);
9.74, 4.2 (S. Garro, Orcieres-Merlette, France).

XTE J1856+053 AND GRO J1849-03
     D. Barret, J. E. Grindlay and P. F. Bloser, Harvard-Smithsonian
Center for Astrophysics (CfA); and B. A. Harmon, S. N. Zhang, C. A. Wilson,
C. R. Robinson and W. S. Paciesas, NASA Marshall Space Flight Center,
report for the BATSE Team: "As part of the galactic-plane survey for
faint x-ray transients (Grindlay et al. 1996, A.Ap. Suppl., in press),
the CfA BATSE Image Search (CBIS) system for automated analysis of
earth-occultation images (Barret et al. 1996, in preparation) was used
to scan sky images of the Aql-Sct-Ser region.  In a 20-50-keV image
integrated over Sept. 3-17 we found evidence of emission from the
recently-discovered x-ray transient XTE J1856+053 (IAUC 6504).  Also,
in images made for the Sept. 3-17 and 16-30 time periods,
CBIS reported weak emission from the recurrent transient GRO
J1849-03, consistent with the 241-day period reported by Zhang et al.
(IAUC 6150).  Analysis of the lightcurves for XTE J1856+053 and GRO
J1849-03 shows peak fluxes in the 20-100-keV band between 30 and
60 mCrab, with XTE J1856+053 peaking in BATSE data on Sept. 7-9,
preceding the ASM peak flux by about 8 days.  This behavior is
characteristic of low-mass-binary transients and could indicate the
presence of a black hole.  GRO J1849-03 has a very broad peak around
Sept. 19."

                      (C) Copyright 1996 CBAT
1996 December 9                (6519)              Brian G. Marsden

Read IAUC 6518  SEARCH Read IAUC 6520

View IAUC 6519 in .dvi or .ps format.

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

Valid HTML 4.01!